1 <?xml version="1.0" encoding="ISO-8859-1"?>
    2 <?xml-stylesheet type="text/xsl" href="jvmti.xsl"?>
    3 <!--
    4  Copyright (c) 2002, 2021, Oracle and/or its affiliates. All rights reserved.
    5  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
    6 
    7  This code is free software; you can redistribute it and/or modify it
    8  under the terms of the GNU General Public License version 2 only, as
    9  published by the Free Software Foundation.
   10 
   11  This code is distributed in the hope that it will be useful, but WITHOUT
   12  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   13  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   14  version 2 for more details (a copy is included in the LICENSE file that
   15  accompanied this code).
   16 
   17  You should have received a copy of the GNU General Public License version
   18  2 along with this work; if not, write to the Free Software Foundation,
   19  Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   20 
   21  Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   22  or visit www.oracle.com if you need additional information or have any
   23  questions.
   24 -->
   25 
   26 <!DOCTYPE specification [
   27    <!ELEMENT specification (title, intro*, functionsection, errorsection,
   28                             eventsection, datasection, issuessection, changehistory)>
   29    <!ATTLIST specification label CDATA #REQUIRED>
   30 
   31    <!ELEMENT title (#PCDATA|jvmti|tm)*>
   32    <!ATTLIST title subtitle CDATA #REQUIRED>
   33 
   34    <!ELEMENT intro ANY>
   35    <!ATTLIST intro id CDATA #IMPLIED
   36                    label CDATA "">
   37 
   38    <!ELEMENT functionsection (intro*, category*)>
   39    <!ATTLIST functionsection label CDATA #REQUIRED>
   40 
   41    <!ELEMENT category ((intro|typedef|uniontypedef|capabilitiestypedef)*,
   42                           (function|callback|elide)*)>
   43    <!ATTLIST category id CDATA #REQUIRED
   44                       label CDATA #REQUIRED>
   45 
   46    <!ELEMENT function (synopsis, typedef*, description?, origin,
   47                          (capabilities|eventcapabilities),
   48                          parameters, errors)>
   49    <!ATTLIST function id CDATA #REQUIRED
   50                       num CDATA #REQUIRED
   51                       phase (onload|onloadOnly|start|live|any) #IMPLIED
   52                       callbacksafe (safe|unsafe) #IMPLIED
   53                       impl CDATA #IMPLIED
   54                       hide CDATA #IMPLIED
   55                       jkernel (yes|no) #IMPLIED
   56                       since CDATA "1.0">
   57 
   58    <!ELEMENT callback ((jmethodID|jfieldID|jframeID|jrawMonitorID|jclass|jthread|jthreadGroup|jobject|
   59                         jvalue|enum|jint|jlong|jfloat|jdouble|jlocation|jboolean|char|uchar|size_t|void),
   60                         synopsis, description?, parameters)>
   61    <!ATTLIST callback id CDATA #REQUIRED
   62                       since CDATA "1.0">
   63 
   64    <!ELEMENT synopsis (#PCDATA|jvmti)*>
   65 
   66    <!ELEMENT typedef (description?, field*)>
   67    <!ATTLIST typedef id CDATA #REQUIRED
   68                      label CDATA #REQUIRED
   69                      since CDATA "1.0">
   70 
   71    <!ELEMENT uniontypedef (description?, field*)>
   72    <!ATTLIST uniontypedef id CDATA #REQUIRED
   73                      label CDATA #REQUIRED
   74                      since CDATA "1.0">
   75 
   76    <!ELEMENT field ((jmethodID|jfieldID|jframeID|jrawMonitorID|jclass|jthread|jthreadGroup|jobject|
   77                      jvalue|enum|jint|jlong|jfloat|jdouble|jlocation|jboolean|char|uchar|size_t|void|allocfieldbuf|inptr|inbuf|outbuf|vmbuf|ptrtype|struct),
   78                     description)>
   79    <!ATTLIST field id CDATA #REQUIRED>
   80 
   81    <!ELEMENT capabilitiestypedef (description?, capabilityfield*)>
   82    <!ATTLIST capabilitiestypedef id CDATA #REQUIRED
   83                      label CDATA #REQUIRED>
   84 
   85    <!ELEMENT capabilityfield (description)>
   86    <!ATTLIST capabilityfield id CDATA #REQUIRED
   87                    disp1 CDATA ""
   88                    disp2 CDATA ""
   89                    since CDATA "1.0">
   90 
   91    <!ELEMENT description ANY>
   92 
   93    <!ELEMENT capabilities (required*, capability*)>
   94 
   95    <!ELEMENT eventcapabilities EMPTY>
   96 
   97    <!ELEMENT required ANY>
   98    <!ATTLIST required id CDATA #REQUIRED>
   99 
  100    <!ELEMENT capability ANY>
  101    <!ATTLIST capability id CDATA #REQUIRED>
  102 
  103    <!ELEMENT parameters (param*)>
  104 
  105    <!ELEMENT param ((jmethodID|jfieldID|jframeID|jrawMonitorID|jclass|jthread|jthreadGroup|jobject|
  106                      jvalue|enum|jint|jlong|jfloat|jdouble|jlocation|jboolean|char|uchar|size_t|void|varargs|struct|ptrtype|
  107                      outptr|allocbuf|allocallocbuf|inptr|inbuf|outbuf|vmbuf|agentbuf),
  108                     description)>
  109    <!ATTLIST param id CDATA #REQUIRED>
  110 
  111    <!ELEMENT jmethodID EMPTY>
  112    <!ATTLIST jmethodID class  CDATA #IMPLIED
  113                        native CDATA #IMPLIED>
  114 
  115    <!ELEMENT jfieldID EMPTY>
  116    <!ATTLIST jfieldID class CDATA #IMPLIED>
  117 
  118    <!ELEMENT jclass EMPTY>
  119    <!ATTLIST jclass method CDATA #IMPLIED
  120                     field  CDATA #IMPLIED>
  121 
  122    <!ELEMENT jframeID EMPTY>
  123    <!ATTLIST jframeID thread CDATA #IMPLIED>
  124 
  125    <!ELEMENT jrawMonitorID EMPTY>
  126 
  127    <!ELEMENT jthread EMPTY>
  128    <!ATTLIST jthread started CDATA #IMPLIED
  129                      null CDATA #IMPLIED
  130                      frame CDATA #IMPLIED
  131                      impl CDATA #IMPLIED>
  132 
  133    <!ELEMENT varargs EMPTY>
  134 
  135    <!ELEMENT jthreadGroup EMPTY>
  136    <!ELEMENT jobject EMPTY>
  137    <!ELEMENT jvalue EMPTY>
  138    <!ELEMENT jchar EMPTY>
  139    <!ELEMENT jint EMPTY>
  140    <!ATTLIST jint min CDATA #IMPLIED>
  141    <!ELEMENT jlong EMPTY>
  142    <!ELEMENT jfloat EMPTY>
  143    <!ELEMENT jdouble EMPTY>
  144    <!ELEMENT jlocation EMPTY>
  145    <!ELEMENT jboolean EMPTY>
  146    <!ELEMENT char EMPTY>
  147    <!ELEMENT uchar EMPTY>
  148    <!ELEMENT size_t EMPTY>
  149    <!ELEMENT void EMPTY>
  150    <!ELEMENT enum (#PCDATA)*>
  151    <!ELEMENT struct (#PCDATA)*>
  152 
  153    <!ELEMENT nullok ANY>
  154 
  155    <!ELEMENT ptrtype     ((struct|jmethodID|jfieldID|jframeID|jrawMonitorID|jclass|jthread|
  156                                    jthreadGroup|jobject|jvalue), nullok?)>
  157 
  158    <!ELEMENT outptr     ((struct|jmethodID|jfieldID|jframeID|jrawMonitorID|jclass|jthread|
  159                                    jthreadGroup|jobject|jvalue|enum|jchar|jint|jlong|jfloat|jdouble|
  160                                    jlocation|jboolean|char|uchar|size_t|void), nullok?)>
  161 
  162    <!ELEMENT allocbuf   ((struct|jmethodID|jfieldID|jframeID|jrawMonitorID|jclass|jthread|
  163                                    jthreadGroup|jobject|jvalue|enum|jint|jlong|jfloat|jdouble|
  164                                    jlocation|jboolean|char|uchar|size_t|void), nullok?)>
  165    <!ATTLIST allocbuf incount CDATA #IMPLIED
  166                       outcount CDATA #IMPLIED>
  167 
  168    <!ELEMENT allocallocbuf   ((struct|jmethodID|jfieldID|jframeID|jrawMonitorID|jclass|jthread|
  169                                    jthreadGroup|jobject|jvalue|enum|jint|jlong|jfloat|jdouble|
  170                                    jlocation|jboolean|char|uchar|size_t|void), nullok?)>
  171    <!ATTLIST allocallocbuf incount CDATA #IMPLIED
  172                       outcount CDATA #IMPLIED>
  173 
  174    <!ELEMENT inptr      (struct, nullok?)>
  175 
  176    <!ELEMENT inbuf      ((struct|jmethodID|jfieldID|jframeID|jrawMonitorID|jclass|jthread|
  177                                    jthreadGroup|jobject|jvalue|enum|jint|jlong|jfloat|jdouble|
  178                                    jlocation|jboolean|char|uchar|size_t|void), nullok?)>
  179    <!ATTLIST inbuf    incount CDATA #IMPLIED>
  180 
  181    <!ELEMENT outbuf     ((struct|jmethodID|jfieldID|jframeID|jrawMonitorID|jclass|jthread|
  182                                    jthreadGroup|jobject|jvalue|enum|jint|jlong|jfloat|jdouble|
  183                                    jlocation|jboolean|char|uchar|size_t|void|outbuf), nullok?)>
  184    <!ATTLIST outbuf   incount CDATA #IMPLIED
  185                       outcount CDATA #IMPLIED>
  186 
  187    <!ELEMENT vmbuf      ((struct|jmethodID|jfieldID|jframeID|jrawMonitorID|jclass|jthread|
  188                                    jthreadGroup|jobject|jvalue|enum|jchar|jint|jlong|jfloat|jdouble|
  189                                    jlocation|jboolean|char|uchar|size_t|void), nullok?)>
  190    <!ATTLIST vmbuf    incount CDATA #IMPLIED
  191                       outcount CDATA #IMPLIED>
  192 
  193    <!ELEMENT agentbuf   ((struct|jmethodID|jfieldID|jframeID|jrawMonitorID|jclass|jthread|
  194                                    jthreadGroup|jobject|jvalue|enum|jint|jlong|jfloat|jdouble|
  195                                    jlocation|jboolean|char|uchar|size_t|void), nullok?)>
  196    <!ATTLIST agentbuf incount CDATA #IMPLIED
  197                       outcount CDATA #IMPLIED>
  198 
  199    <!ELEMENT allocfieldbuf   ((struct|jmethodID|jfieldID|jframeID|jrawMonitorID|jclass|jthread|
  200                                    jthreadGroup|jobject|jvalue|enum|jint|jlong|jfloat|jdouble|
  201                                    jlocation|jboolean|char|uchar|size_t|void))>
  202    <!ATTLIST allocfieldbuf outcount CDATA #IMPLIED>
  203 
  204    <!ELEMENT errors (error*)>
  205 
  206    <!ELEMENT error ANY>
  207    <!ATTLIST error id CDATA #REQUIRED>
  208 
  209    <!ELEMENT errorsection (intro*, errorcategory*)>
  210    <!ATTLIST errorsection label CDATA #REQUIRED>
  211 
  212    <!ELEMENT errorcategory (intro*, errorid*)>
  213    <!ATTLIST errorcategory id CDATA #REQUIRED
  214                            label CDATA #REQUIRED>
  215 
  216    <!ELEMENT errorid ANY>
  217    <!ATTLIST errorid id CDATA #REQUIRED
  218                      num CDATA #REQUIRED>
  219 
  220    <!ELEMENT datasection (intro*, basetypes*)>
  221 
  222    <!ELEMENT basetypes (intro*, basetype*)>
  223    <!ATTLIST basetypes id CDATA #REQUIRED
  224                        label CDATA #REQUIRED>
  225 
  226    <!ELEMENT basetype (definition?,description)>
  227    <!ATTLIST basetype id CDATA #REQUIRED
  228                       name CDATA #IMPLIED>
  229 
  230    <!ELEMENT definition (#PCDATA|jvmti)*>
  231 
  232    <!ELEMENT eventsection (intro*, (event|elide)*)>
  233    <!ATTLIST eventsection label CDATA #REQUIRED>
  234 
  235    <!ELEMENT event (description, origin, typedef*, capabilities, parameters)>
  236    <!ATTLIST event id CDATA #REQUIRED
  237                    label CDATA #REQUIRED
  238                    const CDATA #REQUIRED
  239                    num CDATA #REQUIRED
  240                    phase (onload|start|live|any) #IMPLIED
  241                    filtered (thread|global) #IMPLIED
  242                    since CDATA "1.0">
  243 
  244    <!ELEMENT issuessection (intro*)>
  245    <!ATTLIST issuessection label CDATA #REQUIRED>
  246 
  247    <!ELEMENT changehistory (intro*, change*)>
  248    <!ATTLIST changehistory update CDATA #REQUIRED
  249                            id CDATA #REQUIRED>
  250 
  251    <!ELEMENT change ANY>
  252    <!ATTLIST change date CDATA #REQUIRED
  253                     version CDATA #IMPLIED>
  254 
  255    <!ELEMENT functionlink (#PCDATA|jvmti|code|i|b)*>
  256    <!ATTLIST functionlink id CDATA #REQUIRED>
  257 
  258    <!ELEMENT datalink (#PCDATA|jvmti|code|i|b)*>
  259    <!ATTLIST datalink id CDATA #REQUIRED>
  260 
  261    <!ELEMENT typelink (#PCDATA|jvmti|code|i|b)*>
  262    <!ATTLIST typelink id CDATA #REQUIRED>
  263 
  264    <!ELEMENT fieldlink (#PCDATA|jvmti|code|i|b)*>
  265    <!ATTLIST fieldlink id CDATA #REQUIRED
  266                        struct CDATA #REQUIRED>
  267 
  268    <!ELEMENT paramlink (#PCDATA|jvmti|code|i|b)*>
  269    <!ATTLIST paramlink id CDATA #REQUIRED>
  270 
  271    <!ELEMENT eventlink (#PCDATA|jvmti|code|i|b)*>
  272    <!ATTLIST eventlink id CDATA #REQUIRED>
  273 
  274    <!ELEMENT errorlink (#PCDATA|jvmti|code|i|b|tm)*>
  275    <!ATTLIST errorlink id CDATA #REQUIRED>
  276 
  277    <!ELEMENT externallink (#PCDATA|jvmti|code|i|b|tm)*>
  278    <!ATTLIST externallink id CDATA #REQUIRED>
  279 
  280    <!ELEMENT vmspec EMPTY>
  281    <!ATTLIST vmspec chapter CDATA #IMPLIED>
  282 
  283    <!ELEMENT internallink (#PCDATA|jvmti|code|i|b)*>
  284    <!ATTLIST internallink id CDATA #REQUIRED>
  285 
  286    <!ELEMENT functionphaselist EMPTY>
  287    <!ATTLIST functionphaselist phase (onload|onloadOnly|start|live|any) #REQUIRED>
  288 
  289    <!ELEMENT eventphaselist EMPTY>
  290    <!ATTLIST eventphaselist phase (onload|start|live|any) #REQUIRED>
  291 
  292    <!ELEMENT issue ANY>
  293 
  294    <!ELEMENT rationale ANY>
  295 
  296    <!ELEMENT todo ANY>
  297 
  298    <!ELEMENT origin (#PCDATA)*>
  299 
  300    <!ELEMENT elide (intro|function|callback|event)*>
  301    <!ATTLIST elide why CDATA #IMPLIED>
  302 
  303    <!ELEMENT constants (constant*)>
  304    <!ATTLIST constants id CDATA #REQUIRED
  305                        label CDATA #REQUIRED
  306                        kind (enum|bits|const) #REQUIRED
  307                        since CDATA "1.0">
  308 
  309    <!ELEMENT constant ANY>
  310    <!ATTLIST constant id CDATA #REQUIRED
  311                       num CDATA #REQUIRED>
  312 
  313    <!ELEMENT tm (#PCDATA)>
  314 
  315    <!ELEMENT i (#PCDATA|jvmti|tm)*>
  316 
  317    <!ELEMENT b (#PCDATA|jvmti|code)*>
  318 
  319    <!ELEMENT code (#PCDATA|space)*>
  320 
  321    <!ELEMENT pre ANY>
  322 
  323    <!ELEMENT space EMPTY>
  324 
  325    <!ELEMENT jvmti EMPTY>
  326 
  327    <!ELEMENT example (#PCDATA|i)*>
  328 
  329    <!ELEMENT br EMPTY>
  330 
  331    <!ELEMENT p EMPTY>
  332 
  333    <!ELEMENT blockquote ANY>
  334 
  335    <!ELEMENT dl  (dt|dd)+>
  336 
  337    <!ELEMENT dd  ANY>
  338 
  339    <!ELEMENT dt  (#PCDATA|jvmti|code|i|b)*>
  340 
  341    <!ELEMENT table  (tr)+>
  342 
  343    <!ELEMENT tr  (td|th)*>
  344    <!ATTLIST tr class CDATA #IMPLIED>
  345 
  346    <!ELEMENT td  ANY>
  347    <!ATTLIST td class CDATA #IMPLIED>
  348 
  349    <!ELEMENT th  ANY>
  350    <!ATTLIST th class CDATA #IMPLIED
  351                 scope (col|row) #IMPLIED>
  352 
  353    <!ELEMENT ul  (li)+>
  354    <!ATTLIST ul type (disc|circle|square) "disc">
  355 
  356    <!ELEMENT li  ANY>
  357  ]>
  358 
  359 <specification label="JVM(TM) Tool Interface">
  360   <title subtitle="Version">
  361     <tm>JVM</tm> Tool Interface
  362   </title>
  363 
  364   <intro id="whatIs" label="What is the JVM Tool Interface?">
  365     The <tm>JVM</tm> Tool Interface (<jvmti/>)
  366     is a programming interface used by development and monitoring tools.
  367     It provides both a way to inspect the state and
  368     to control the execution of applications running in the
  369     <tm>Java</tm> virtual machine (VM).
  370     <p/>
  371     <jvmti/> is intended to provide a VM interface for the full breadth of tools
  372     that need access to VM state, including but not limited to: profiling,
  373     debugging, monitoring, thread analysis, and coverage analysis tools.
  374     <p/>
  375     <jvmti/> may not be available in all implementations of the <tm>Java</tm> virtual
  376     machine.
  377     <p/>
  378     <jvmti/> is a two-way interface.
  379     A client of <jvmti/>, hereafter called an <i>agent</i>,
  380     can be notified of
  381     interesting occurrences through <internallink id="EventSection">events</internallink>.
  382     <jvmti/>
  383     can query and control the application through many
  384     <internallink id="FunctionSection">functions</internallink>,
  385     either in response to events or
  386     independent of them.
  387     <p/>
  388     Agents run in the same process with and communicate directly with
  389     the virtual machine executing
  390     the application being examined.  This communication is
  391     through a native interface (<jvmti/>). The native in-process interface allows
  392     maximal control with minimal intrusion on the part of a tool.
  393     Typically, agents are relatively compact. They can be controlled
  394     by a separate process which implements the bulk of a tool's
  395     function without interfering with the target application's normal execution.
  396   </intro>
  397 
  398   <intro id="architecture" label="Architecture">
  399     Tools can be written directly to <jvmti/> or indirectly
  400     through higher level interfaces.
  401     The Java Platform Debugger Architecture includes <jvmti/>, but also
  402     contains higher-level, out-of-process debugger interfaces. The higher-level
  403     interfaces are more appropriate than <jvmti/> for many tools.
  404     For more information on the Java Platform Debugger Architecture,
  405     see the
  406     <externallink id="jpda/architecture.html">Java
  407       Platform Debugger Architecture website</externallink>.
  408   </intro>
  409 
  410   <intro id="writingAgents" label="Writing Agents">
  411     Agents can be written in any native language that supports C
  412     language calling conventions and C or C++
  413     definitions.
  414     <p/>
  415     The function, event, data type, and constant definitions needed for
  416     using <jvmti/> are defined in the include file <code>jvmti.h</code>.
  417     To use these definitions add the <tm>J2SE</tm> include directory
  418     to your include path and add
  419     <example>
  420 #include &lt;jvmti.h&gt;
  421     </example>
  422     to your source code.
  423   </intro>
  424 
  425   <intro id="deployingAgents" label="Deploying Agents">
  426     An agent is deployed in a platform specific manner but is typically the
  427     platform equivalent of a dynamic library. On the <tm>Windows</tm> operating
  428     system, for example, an agent library is a "Dynamic Linked Library" (DLL).
  429     On <tm>Linux</tm> Operating Environment, an agent library is a shared object
  430     (<code>.so</code> file).
  431     <p/>
  432 
  433     An agent may be started at VM startup by specifying the agent library
  434     name using a <internallink id="starting">command line option</internallink>.
  435     Some implementations may support a mechanism to <internallink id="onattach">
  436     start agents</internallink> in the live <functionlink id="GetPhase">phase</functionlink>.
  437     The details of how this is initiated are implementation specific.
  438   </intro>
  439 
  440     <intro id="entryPoint" label="Statically Linked Agents (since version 1.2.3)">
  441 
  442       A native JVMTI Agent may be <i>statically linked</i> with the VM.
  443       The manner in which the library and VM image are combined is
  444       implementation-dependent.
  445       An agent L whose image has been combined with the VM is defined as
  446       <i>statically linked</i> if and only if the agent exports a function
  447       called Agent_OnLoad_L.
  448 <p/>
  449       If a <i>statically linked</i> agent L exports a function called
  450       Agent_OnLoad_L and a function called Agent_OnLoad, the Agent_OnLoad
  451       function will be ignored.
  452       If an agent L is <i>statically linked</i>, an Agent_OnLoad_L
  453       function will be invoked with the same arguments and expected return
  454       value as specified for the Agent_OnLoad function.
  455       An agent L that is <i>statically linked</i> will prohibit an agent of
  456       the same name from being loaded dynamically.
  457 <p/>
  458       The VM will invoke the Agent_OnUnload_L function of the agent, if such
  459       a function is exported, at the same point during VM execution as it would
  460       have called the dynamic entry point Agent_OnUnLoad. A statically loaded
  461       agent cannot be unloaded. The Agent_OnUnload_L function will still be
  462       called to do any other agent shutdown related tasks.
  463       If a <i>statically linked</i> agent L exports a function called
  464       Agent_OnUnLoad_L and a function called Agent_OnUnLoad, the Agent_OnUnLoad
  465       function will be ignored.
  466 <p/>
  467       If an agent L is <i>statically linked</i>, an Agent_OnAttach_L function
  468       will be invoked with the same arguments and expected return value as
  469       specified for the Agent_OnAttach function.
  470       If a <i>statically linked</i> agent L exports a function called
  471       Agent_OnAttach_L and a function called Agent_OnAttach, the Agent_OnAttach
  472       function will be ignored.
  473 </intro>
  474 
  475   <intro id="starting" label="Agent Command Line Options">
  476     The term "command-line option" is used below to
  477     mean options supplied in the <code>JavaVMInitArgs</code> argument
  478     to the <code>JNI_CreateJavaVM</code> function of the JNI
  479     Invocation API.
  480     <p/>
  481     One of the two following
  482     command-line options is used on VM startup to
  483     properly load and run agents.
  484     These arguments identify the library containing
  485     the agent as well as an options
  486     string to be passed in at startup.
  487     <dl>
  488       <dt><code>-agentlib:</code><i>&lt;agent-lib-name&gt;</i><code>=</code><i>&lt;options&gt;</i></dt>
  489       <dd>
  490         The name following <code>-agentlib:</code> is the name of the
  491         library to load.  Lookup of the library, both its full name and location,
  492         proceeds in a platform-specific manner.
  493         Typically, the <i>&lt;agent-lib-name&gt;</i> is expanded to an
  494         operating system specific file name.
  495         The <i>&lt;options&gt;</i> will be passed to the agent on start-up.
  496         For example, if the option
  497         <code>-agentlib:foo=opt1,opt2</code> is specified, the VM will attempt to
  498         load the shared library <code>foo.dll</code> from the system <code>PATH</code>
  499         under <tm>Windows</tm> or <code>libfoo.so</code> from the
  500         <code>LD_LIBRARY_PATH</code> under <tm>Linux</tm>.
  501         If the agent library is statically linked into the executable
  502         then no actual loading takes place.
  503     <p/>
  504       </dd>
  505       <dt><code>-agentpath:</code><i>&lt;path-to-agent&gt;</i><code>=</code><i>&lt;options&gt;</i></dt>
  506       <dd>
  507         The path following <code>-agentpath:</code> is the absolute path from which
  508         to load the library.
  509         No library name expansion will occur.
  510         The <i>&lt;options&gt;</i> will be passed to the agent on start-up.
  511         For example, if the option
  512         <code>-agentpath:c:\myLibs\foo.dll=opt1,opt2</code> is specified, the VM will attempt to
  513         load the shared library <code>c:\myLibs\foo.dll</code>. If the agent
  514         library is statically linked into the executable
  515         then no actual loading takes place.
  516     <p/>
  517       </dd>
  518     </dl>
  519     For a dynamic shared library agent, the start-up routine
  520     <internallink id="onload"><code>Agent_OnLoad</code></internallink>
  521     in the library will be invoked. If the agent library is statically linked
  522     into the executable then the system will attempt to invoke the
  523     <code>Agent_OnLoad_&lt;agent-lib-name&gt;</code> entry point where
  524     &lt;agent-lib-name&gt; is the basename of the
  525     agent. In the above example <code>-agentpath:c:\myLibs\foo.dll=opt1,opt2</code>,
  526     the system will attempt to find and call the <code>Agent_OnLoad_foo</code> start-up routine.
  527     <p/>
  528     Libraries loaded with <code>-agentlib:</code> or <code>-agentpath:</code>
  529     will be searched for JNI native method implementations to facilitate the
  530     use of Java programming language code in tools, as is needed for
  531     <internallink id="bci">bytecode instrumentation</internallink>.
  532     <p/>
  533     The agent libraries will be searched after all other libraries have been
  534     searched (agents wishing to override or intercept the native method
  535     implementations of non-agent methods can use the
  536     <eventlink id="NativeMethodBind">NativeMethodBind event</eventlink>).
  537     <p/>
  538     These switches do the above and nothing more - they do not change the
  539     state of the VM or <jvmti/>.  No command line options are needed
  540     to enable <jvmti/>
  541     or aspects of <jvmti/>, this is handled programmatically
  542     by the use of
  543     <internallink id="capability">capabilities</internallink>.
  544   </intro>
  545 
  546   <intro id="startup" label="Agent Start-Up">
  547     The VM starts each agent by invoking a start-up function.
  548     If the agent is started in the <code>OnLoad</code>
  549     <functionlink id="GetPhase">phase</functionlink> the function
  550     <internallink id="onload"><code>Agent_OnLoad</code></internallink>
  551     or <internallink id="onload"><code>Agent_OnLoad_L</code></internallink>
  552     for statically linked agents will be invoked.
  553     If the agent is started in the live
  554     <functionlink id="GetPhase">phase</functionlink> the function
  555     <internallink id="onattach"><code>Agent_OnAttach</code></internallink>
  556     or <internallink id="onattach"><code>Agent_OnAttach_L</code></internallink>
  557     for statically linked agents will be invoked.
  558     Exactly one call to a start-up function is made per agent.
  559   </intro>
  560 
  561   <intro id="onload" label="Agent Start-Up (OnLoad phase)">
  562     If an agent is started during the <code>OnLoad</code> phase then its
  563     agent library must export a start-up function with the following prototype:
  564     <example>
  565 JNIEXPORT jint JNICALL
  566 Agent_OnLoad(JavaVM *vm, char *options, void *reserved)</example>
  567     Or for a statically linked agent named 'L':
  568     <example>
  569 JNIEXPORT jint JNICALL
  570 Agent_OnLoad_L(JavaVM *vm, char *options, void *reserved)</example>
  571 
  572     The VM will start the agent by calling this function.
  573     It will be called early enough in VM initialization that:
  574     <ul>
  575       <li><functionlink id="SetSystemProperty">system properties</functionlink>
  576         may be set before they have been used in the start-up of the VM</li>
  577       <li>the full set of
  578         <internallink id="capability">capabilities</internallink>
  579         is still available (note that capabilities that configure the VM
  580         may only be available at this time--see the
  581         <internallink id="capability">Capability function section</internallink>)</li>
  582       <li>no bytecodes have executed</li>
  583       <li>no classes have been loaded</li>
  584       <li>no objects have been created</li>
  585     </ul>
  586     <p/>
  587     The VM will call the <code>Agent_OnLoad</code> or
  588     <code>Agent_OnLoad_&lt;agent-lib-name&gt;</code> function with
  589     <i>&lt;options&gt;</i> as the second argument -
  590     that is, using the command-line option examples,
  591     <code>"opt1,opt2"</code> will be passed to the <code>char *options</code>
  592     argument of <code>Agent_OnLoad</code>.
  593     The <code>options</code> argument is encoded as a
  594     <internallink id="mUTF">modified UTF-8</internallink> string.
  595     If <i>=&lt;options&gt;</i> is not specified,
  596     a zero length string is passed to <code>options</code>.
  597     The lifespan of the <code>options</code> string is the
  598     <code>Agent_OnLoad</code> or <code>Agent_OnLoad_&lt;agent-lib-name&gt;</code>
  599     call.  If needed beyond this time the string or parts of the string must
  600     be copied.
  601     The period between when <code>Agent_OnLoad</code> is called and when it
  602     returns is called the <i>OnLoad phase</i>.
  603     Since the VM is not initialized during the OnLoad
  604     <functionlink id="GetPhase">phase</functionlink>,
  605     the set of allowed operations
  606     inside <code>Agent_OnLoad</code> is restricted (see the function descriptions for the
  607     functionality available at this time).
  608     The agent can safely process the options and set
  609     event callbacks with <functionlink id="SetEventCallbacks"></functionlink>. Once
  610     the VM initialization event is received
  611     (that is, the <eventlink id="VMInit">VMInit</eventlink>
  612     callback is invoked), the agent
  613     can complete its initialization.
  614     <rationale>
  615       Early startup is required so that agents can set the desired capabilities,
  616       many of which must be set before the VM is initialized.
  617       In JVMDI, the -Xdebug command-line option provided
  618       very coarse-grain control of capabilities.
  619       JVMPI implementations use various tricks to provide a single "JVMPI on" switch.
  620       No reasonable command-line
  621       option could provide the fine-grain of control required to balance needed capabilities vs
  622       performance impact.
  623       Early startup is also needed so that agents can control the execution
  624       environment - modifying the file system and system properties to install
  625       their functionality.
  626     </rationale>
  627     <p/>
  628     The return value from <code>Agent_OnLoad</code> or
  629     <code>Agent_OnLoad_&lt;agent-lib-name&gt;</code> is used to indicate an error.
  630     Any value other than zero indicates an error and causes termination of the VM.
  631   </intro>
  632 
  633   <intro id="onattach" label="Agent Start-Up (Live phase)">
  634     A VM may support a mechanism that allows agents to be started in the VM during the live
  635     <functionlink id="GetPhase">phase</functionlink>. The details of how this is supported,
  636     are implementation specific. For example, a tool may use some platform specific mechanism,
  637     or implementation specific API, to attach to the running VM, and request it start a given
  638     agent.
  639     <p/>
  640     If an agent is started during the live phase then its agent library
  641     must export a start-up function
  642     with the following prototype:
  643     <example>
  644 JNIEXPORT jint JNICALL
  645 Agent_OnAttach(JavaVM* vm, char *options, void *reserved)</example>
  646 Or for a statically linked agent named 'L':
  647     <example>
  648 JNIEXPORT jint JNICALL
  649 Agent_OnAttach_L(JavaVM* vm, char *options, void *reserved)</example>
  650 
  651     <p/>
  652     The VM will start the agent by calling this function.
  653     It will be called in the context of a thread
  654     that is attached to the VM. The first argument <i>&lt;vm&gt;</i> is the Java VM.
  655     The <i>&lt;options&gt;</i> argument is the startup options provided to the agent.
  656     <i>&lt;options&gt;</i> is encoded as a <internallink id="mUTF">modified UTF-8
  657     </internallink> string.
  658     If startup options were not provided, a zero length string is passed to
  659     <code>options</code>. The lifespan of the <code>options</code> string is the
  660     <code>Agent_OnAttach</code> or <code>Agent_OnAttach_&lt;agent-lib-name&gt;</code> call.
  661     If needed beyond this time the string or parts of the string must be copied.
  662     <p/>
  663     Note that some <internallink id="capability">capabilities</internallink>
  664     may not be available in the live phase.
  665     <p/>
  666     The <code>Agent_OnAttach</code> or <code>Agent_OnAttach_&lt;agent-lib-name
  667     &gt;</code> function initializes the agent and returns a value
  668     to the VM to indicate if an error occurred. Any value other than zero indicates an error.
  669     An error does not cause the VM to terminate. Instead the VM ignores the error, or takes
  670     some implementation specific action -- for example it might print an error to standard error,
  671     or record the error in a system log.
  672   </intro>
  673 
  674   <intro id="onunload" label="Agent Shutdown">
  675     The library may optionally export a
  676     shutdown function with the following prototype:
  677     <example>
  678 JNIEXPORT void JNICALL
  679 Agent_OnUnload(JavaVM *vm)</example>
  680     Or for a statically linked agent named 'L':
  681     <example>
  682 JNIEXPORT void JNICALL
  683 Agent_OnUnload_L(JavaVM *vm)</example>
  684 
  685     This function will be called by the VM when the library is about to be unloaded.
  686     The library will be unloaded (unless it is statically linked into the
  687     executable) and this function will be called if some platform specific
  688     mechanism causes the unload (an unload mechanism is not specified in this document)
  689     or the library is (in effect) unloaded by the termination of the VM.
  690     VM termination includes normal termination and VM failure, including start-up failure,
  691     but not, of course, uncontrolled shutdown. An implementation may also
  692     choose to not call this function if the <code>Agent_OnAttach</code>/
  693     <code>Agent_OnAttach_L</code> function reported an error (returned a non-zero value).
  694     Note the distinction between this function and the
  695     <eventlink id="VMDeath">VM Death event</eventlink>: for the VM Death event
  696     to be sent, the VM must have run at least to the point of initialization and a valid
  697     <jvmti/> environment must exist which has set a callback for VMDeath
  698     and enabled the event.
  699     None of these are required for <code>Agent_OnUnload</code> or
  700     <code>Agent_OnUnload_&lt;agent-lib-name&gt;</code> and this function
  701     is also called if the library is unloaded for other reasons.
  702     In the case that a VM Death event is sent, it will be sent before this
  703     function is called (assuming this function is called due to VM termination).
  704     This function can be used to clean-up resources allocated by the agent.
  705   </intro>
  706 
  707   <intro id="tooloptions" label="JAVA_TOOL_OPTIONS">
  708     Since the command-line cannot always be accessed or modified, for example in embedded VMs
  709     or simply VMs launched deep within scripts, a <code>JAVA_TOOL_OPTIONS</code> variable is
  710     provided so that agents may be launched in these cases.
  711     <p/>
  712     Platforms which support environment variables or other named strings, may support the
  713     <code>JAVA_TOOL_OPTIONS</code> variable.  This variable will be broken into options at white-space
  714     boundaries.  White-space characters include space, tab, carriage-return, new-line,
  715     vertical-tab, and form-feed.  Sequences of white-space characters are considered
  716     equivalent to a single white-space character.  No white-space is included in the options
  717     unless quoted.  Quoting is as follows:
  718     <ul>
  719         <li>All characters enclosed between a pair of single quote marks (''), except a single
  720         quote, are quoted.</li>
  721         <li>Double quote characters have no special meaning inside a pair of single quote marks.</li>
  722         <li>All characters enclosed between a pair of double quote marks (""), except a double
  723         quote, are quoted.</li>
  724         <li>Single quote characters have no special meaning inside a pair of double quote marks.</li>
  725         <li>A quoted part can start or end anywhere in the variable.</li>
  726         <li>White-space characters have no special meaning when quoted -- they are included in
  727         the option like any other character and do not mark white-space boundaries.</li>
  728         <li>The pair of quote marks is not included in the option.</li>
  729     </ul>
  730     <code>JNI_CreateJavaVM</code> (in the JNI Invocation API) will prepend these options to the options supplied
  731     in its <code>JavaVMInitArgs</code> argument. Platforms may disable this feature in cases where security is
  732     a concern; for example, the Reference Implementation disables this feature on Unix systems when
  733     the effective user or group ID differs from the real ID.
  734     This feature is intended to support the initialization of tools -- specifically including the
  735     launching of native or Java programming language agents.  Multiple tools may wish to use this
  736     feature, so the variable should not be overwritten, instead,  options should be appended to
  737     the variable.  Note that since the variable is processed at the time of the JNI Invocation
  738     API create VM call, options processed by a launcher (e.g., VM selection options) will not be handled.
  739   </intro>
  740 
  741   <intro id="environments" label="Environments">
  742     The <jvmti/> specification supports the use of multiple simultaneous
  743     <jvmti/> agents.
  744     Each agent has its own <jvmti/> environment.
  745     That is, the <jvmti/> state is
  746     separate for each agent - changes to one environment do not affect the
  747     others.  The state of a <jvmti/>
  748     environment includes:
  749     <ul>
  750       <li><functionlink id="SetEventCallbacks">the event callbacks</functionlink></li>
  751       <li><functionlink id="SetEventNotificationMode">the set of events which are enabled</functionlink></li>
  752       <li><internallink id="capability">the capabilities</internallink></li>
  753       <li><internallink id="memory">the memory allocation/deallocation hooks</internallink></li>
  754     </ul>
  755     Although their <jvmti/> state
  756     is separate, agents inspect and modify the shared state
  757     of the VM, they also share the native environment in which they execute.
  758     As such, an agent can perturb the results of other agents or cause them
  759     to fail.  It is the responsibility of the agent writer to specify the level
  760     of compatibility with other agents.  <jvmti/> implementations are not capable
  761     of preventing destructive interactions between agents. Techniques to reduce
  762     the likelihood of these occurrences are beyond the scope of this document.
  763     <p/>
  764     An agent creates a <jvmti/> environment
  765     by passing a <jvmti/> version
  766     as the interface ID to the JNI Invocation API function
  767     <externallink id="jni/invocation.html#getenv">
  768       <code>GetEnv</code></externallink>.
  769     See <internallink id="jvmtiEnvAccess">Accessing <jvmti/> Functions</internallink>
  770     for more details on the creation and use of
  771     <jvmti/> environments.
  772     Typically, <jvmti/> environments are created by calling <code>GetEnv</code> from
  773     <internallink id="onload"><code>Agent_OnLoad</code></internallink>.
  774   </intro>
  775 
  776   <intro id="bci" label="Bytecode Instrumentation">
  777     This interface does not include some events that one might expect in an interface with
  778     profiling support.  Some examples include full speed
  779     method enter and exit events.  The interface instead provides support for
  780     <i>bytecode instrumentation</i>, the ability to alter the Java virtual machine
  781     bytecode instructions which comprise the target program.  Typically, these alterations
  782     are to add "events" to the code of a method - for example, to add, at the beginning of a method,
  783     a call to <code>MyProfiler.methodEntered()</code>.
  784     Since the changes are purely additive, they do not modify application
  785     state or behavior.
  786     Because the inserted agent code is standard bytecodes, the VM can run at full speed,
  787     optimizing not only the target program but also the instrumentation.  If the
  788     instrumentation does not involve switching from bytecode execution, no expensive
  789     state transitions are needed.  The result is high performance events.
  790     This approach also provides complete control to the agent: instrumentation can be
  791     restricted to "interesting" portions of the code (e.g., the end user's code) and
  792     can be conditional.  Instrumentation can run entirely in Java programming language
  793     code or can call into the native agent.  Instrumentation can simply maintain
  794     counters or can statistically sample events.
  795     <p/>
  796     Instrumentation can be inserted in one of three ways:
  797     <ul>
  798       <li>
  799         Static Instrumentation: The class file is instrumented before it
  800         is loaded into the VM - for example, by creating a duplicate directory of
  801         <code>*.class</code> files which have been modified to add the instrumentation.
  802         This method is extremely awkward and, in general, an agent cannot know
  803         the origin of the class files which will be loaded.
  804       </li>
  805       <li>
  806         Load-Time Instrumentation: When a class file is loaded by the VM, the raw
  807         bytes of the class file are sent for instrumentation to the agent.
  808         The <eventlink id="ClassFileLoadHook"/>
  809         event, triggered by the class load,
  810         provides this functionality.  This mechanism provides efficient
  811         and complete access to one-time instrumentation.
  812       </li>
  813       <li>
  814         Dynamic Instrumentation: A class which is already loaded (and possibly
  815         even running) is modified.  This optional feature is provided by the
  816         <eventlink id="ClassFileLoadHook"/> event, triggered by calling the
  817         <functionlink id="RetransformClasses"/> function.
  818         Classes can be modified multiple times and can be returned to their
  819         original state.
  820         The mechanism allows instrumentation which changes during the
  821         course of execution.
  822       </li>
  823     </ul>
  824     <p/>
  825     The class modification functionality provided in this interface
  826     is intended to provide a mechanism for instrumentation
  827     (the <eventlink id="ClassFileLoadHook"/> event
  828     and the <functionlink id="RetransformClasses"/> function)
  829     and, during development, for fix-and-continue debugging
  830     (the <functionlink id="RedefineClasses"/> function).
  831     <p/>
  832     Care must be taken to avoid perturbing dependencies, especially when
  833     instrumenting core classes.  For example, an approach to getting notification
  834     of every object allocation is to instrument the constructor on
  835     <code>Object</code>.  Assuming that the constructor is initially
  836     empty, the constructor could be changed to:
  837     <example>
  838       public Object() {
  839         MyProfiler.allocationTracker(this);
  840       }
  841     </example>
  842     However, if this change was made using the
  843     <eventlink id="ClassFileLoadHook"/>
  844     event then this might impact a typical VM as follows:
  845     the first created object will call the constructor causing a class load of
  846     <code>MyProfiler</code>; which will then cause
  847     object creation, and since <code>MyProfiler</code> isn't loaded yet,
  848     infinite recursion; resulting in a stack overflow.  A refinement of this
  849     would be to delay invoking the tracking method until a safe time.  For
  850     example, <code>trackAllocations</code> could be set in the
  851     handler for the <code>VMInit</code> event.
  852     <example>
  853       static boolean trackAllocations = false;
  854 
  855       public Object() {
  856         if (trackAllocations) {
  857           MyProfiler.allocationTracker(this);
  858         }
  859       }
  860     </example>
  861     <p/>
  862     The <functionlink id="SetNativeMethodPrefix"/> allows native methods
  863     to be instrumented by the use of wrapper methods.
  864   </intro>
  865 
  866 <intro id="bcimodules" label="Bytecode Instrumentation of code in modules">
  867   Agents can use the functions <functionlink id="AddModuleReads"/>,
  868   <functionlink id="AddModuleExports"/>, <functionlink id="AddModuleOpens"/>,
  869   <functionlink id="AddModuleUses"/> and <functionlink id="AddModuleProvides"/>
  870   to update a module to expand the set of modules that it reads, the set of
  871   packages that it exports or opens to other modules, or the services that it
  872   uses and provides.
  873   <p/>
  874   As an aid to agents that deploy supporting classes on the search path of
  875   the bootstrap class loader, or the search path of the class loader that
  876   loads the main class, the Java virtual machine arranges for the module
  877   of classes transformed by the <eventlink id="ClassFileLoadHook"/> event to
  878   read the unnamed module of both class loaders.
  879 </intro>
  880 
  881   <intro id="mUTF" label="Modified UTF-8 String Encoding">
  882     <jvmti/> uses modified UTF-8 to encode character strings.
  883     This is the same encoding used by JNI.
  884     Modified UTF-8 differs
  885     from standard UTF-8 in the representation of supplementary characters
  886     and of the null character. See the
  887     <externallink id="jni/types.html#modified-utf-8-strings">
  888       Modified UTF-8 Strings</externallink>
  889     section of the JNI specification for details.
  890   </intro>
  891 
  892   <intro id="context" label="Specification Context">
  893     Since this interface provides access to the state of applications running in the
  894     Java virtual machine;
  895     terminology refers to the Java platform and not the native
  896     platform (unless stated otherwise).  For example:
  897     <ul>
  898       <li>"thread" means Java programming language thread.</li>
  899       <li>"stack frame" means Java virtual machine stack frame.</li>
  900       <li>"class" means Java programming language class.</li>
  901       <li>"heap" means Java virtual machine heap.</li>
  902       <li>"monitor" means Java programming language object monitor.</li>
  903     </ul>
  904     <p/>
  905     Sun, Sun Microsystems, the Sun logo, Java, and JVM
  906     are trademarks or registered trademarks of Oracle
  907     and/or its affiliates, in the U.S. and other countries.
  908   </intro>
  909 
  910 
  911 <functionsection label="Functions">
  912   <intro id="jvmtiEnvAccess" label="Accessing Functions">
  913     Native code accesses <jvmti/> features
  914     by calling <jvmti/> functions.
  915     Access to <jvmti/> functions is by use of an interface pointer
  916     in the same manner as
  917     <externallink id="jni/design.html">Java
  918       Native Interface (JNI) functions</externallink> are accessed.
  919     The <jvmti/> interface pointer is called the
  920     <i>environment pointer</i>.
  921     <p/>
  922     An environment pointer is a pointer to an environment and has
  923     the type <code>jvmtiEnv*</code>.
  924     An environment has information about its <jvmti/> connection.
  925     The first value in the environment is a pointer to the function table.
  926     The function table is an array of pointers to <jvmti/> functions.
  927     Every function pointer is at a predefined offset inside the
  928     array.
  929     <p/>
  930     When used from the C language:
  931     double indirection is used to access the functions;
  932     the environment pointer provides context and is the first
  933     parameter of each function call; for example:
  934     <example>
  935 jvmtiEnv *jvmti;
  936 ...
  937 jvmtiError err = (*jvmti)->GetLoadedClasses(jvmti, &amp;class_count, &amp;classes);
  938     </example>
  939     <p/>
  940     When used from the C++ language:
  941     functions are accessed as member functions of <code>jvmtiEnv</code>;
  942     the environment pointer is not passed to the function call; for example:
  943     <example>
  944 jvmtiEnv *jvmti;
  945 ...
  946 jvmtiError err = jvmti->GetLoadedClasses(&amp;class_count, &amp;classes);
  947     </example>
  948     Unless otherwise stated, all examples and declarations in this
  949     specification use the C language.
  950     <p/>
  951     A <jvmti/> environment can be obtained through the JNI Invocation API
  952     <code>GetEnv</code> function:
  953     <example>
  954 jvmtiEnv *jvmti;
  955 ...
  956 (*jvm)->GetEnv(jvm, &amp;jvmti, JVMTI_VERSION_1_0);
  957     </example>
  958     Each call to <code>GetEnv</code>
  959     creates a new <jvmti/> connection and thus
  960     a new <jvmti/> environment.
  961     The <code>version</code> argument of <code>GetEnv</code> must be
  962     a <jvmti/> version.
  963     The returned environment may have a different version than the
  964     requested version but the returned environment must be compatible.
  965     <code>GetEnv</code> will return <code>JNI_EVERSION</code> if a
  966     compatible version is not available, if <jvmti/> is not supported or
  967     <jvmti/> is not supported in the current VM configuration.
  968     Other interfaces may be added for creating <jvmti/> environments
  969     in specific contexts.
  970     Each environment has its own state (for example,
  971     <functionlink id="SetEventNotificationMode">desired events</functionlink>,
  972     <functionlink id="SetEventCallbacks">event handling functions</functionlink>, and
  973     <functionlink id="AddCapabilities">capabilities</functionlink>).
  974     An environment is released with
  975     <functionlink id="DisposeEnvironment"></functionlink>.
  976     Thus, unlike JNI which has one environment per thread, <jvmti/> environments work
  977     across threads and are created dynamically.
  978   </intro>
  979 
  980   <intro id="functionReturn" label="Function Return Values">
  981     <jvmti/> functions always return an
  982     <internallink id="ErrorSection">error code</internallink> via the
  983     <datalink id="jvmtiError"/> function return value.
  984     Some functions can return additional
  985     values through pointers provided by the calling function.
  986     In some cases, <jvmti/> functions allocate memory that your program must
  987     explicitly deallocate. This is indicated in the individual <jvmti/>
  988     function descriptions.  Empty lists, arrays, sequences, etc are
  989     returned as <code>NULL</code>.
  990     <p/>
  991     In the event that the <jvmti/> function encounters
  992     an error (any return value other than <code>JVMTI_ERROR_NONE</code>) the values
  993     of memory referenced by argument pointers is undefined, but no memory
  994     will have been allocated and no global references will have been allocated.
  995     If the error occurs because of invalid input, no action will have occurred.
  996   </intro>
  997 
  998 <intro id="refs" label="Managing JNI Object References">
  999     <jvmti/> functions identify objects with JNI references
 1000     (<datalink id="jobject"/> and <datalink id="jclass"/>)
 1001     and their derivatives
 1002     (<datalink id="jthread"/> and <datalink id="jthreadGroup"/>).
 1003     References passed to
 1004     <jvmti/> functions can be either global or local, but they must be
 1005     strong references. All references returned by <jvmti/> functions are
 1006     local references--these local references are created
 1007     during the <jvmti/> call.
 1008     Local references are a resource that must be managed (see the
 1009     <externallink id="jni/functions.html#local-references">
 1010       JNI Documentation</externallink>).
 1011     When threads return from native code all local references
 1012     are freed.  Note that some threads, including typical
 1013     agent threads, will never return from native code.
 1014     A thread is ensured the ability to create sixteen local
 1015     references without the need for any explicit management.
 1016     For threads executing a limited number of <jvmti/> calls before
 1017     returning from native code
 1018     (for example, threads processing events),
 1019     it may be determined that no explicit management
 1020     is needed.
 1021     However, long running agent threads will need explicit
 1022     local reference management--usually with the JNI functions
 1023     <code>PushLocalFrame</code> and <code>PopLocalFrame</code>.
 1024     Conversely, to preserve references beyond the
 1025     return from native code, they must be converted to global references.
 1026     These rules do not apply to <datalink id="jmethodID"/> and <datalink id="jfieldID"/>
 1027     as they are not <datalink id="jobject"/>s.
 1028 </intro>
 1029 
 1030     <intro id="prereqState" label="Prerequisite State for Calling Functions">
 1031       Unless the function explicitly states that the agent must bring
 1032       a thread or the VM to a particular state (for example, suspended),
 1033       the <jvmti/> implementation is responsible for bringing the VM to a
 1034       safe and consistent state for performing the function.
 1035     </intro>
 1036 
 1037     <intro id="functionsExceptions" label="Exceptions and Functions">
 1038       <jvmti/> functions never throw exceptions; error conditions are
 1039       communicated via the
 1040       <internallink id="functionReturn">function return value</internallink>.
 1041       Any existing exception state is preserved across a call to a
 1042       <jvmti/> function.
 1043       See the
 1044       <externallink
 1045         id="jni/design.html#java-exceptions"
 1046              >Java Exceptions</externallink>
 1047       section of the JNI specification for information on handling exceptions.
 1048     </intro>
 1049 
 1050   <category id="memory" label="Memory Management">
 1051     <intro>
 1052       These functions provide for the allocation and deallocation of
 1053       memory used by <jvmti/> functionality and can be used to provide
 1054       working memory for agents.
 1055       Memory managed by <jvmti/> is not compatible with other memory
 1056       allocation libraries and mechanisms.
 1057     </intro>
 1058 
 1059     <function id="Allocate" jkernel="yes" phase="any" callbacksafe="safe" impl="notrace" num="46">
 1060       <synopsis>Allocate</synopsis>
 1061       <description>
 1062         Allocate an area of memory through the <jvmti/> allocator.
 1063         The allocated
 1064         memory should be freed with <functionlink id="Deallocate"></functionlink>.
 1065       </description>
 1066       <origin>jvmdi</origin>
 1067       <capabilities>
 1068       </capabilities>
 1069       <parameters>
 1070         <param id="size">
 1071           <jlong/>
 1072           <description>
 1073             The number of bytes to allocate.
 1074             <rationale>
 1075               <code>jlong</code> is used for compatibility with JVMDI.
 1076             </rationale>
 1077           </description>
 1078         </param>
 1079         <param id="mem_ptr">
 1080           <allocbuf incount="size"><uchar/></allocbuf>
 1081           <description>
 1082             On return, a pointer to the beginning of the allocated memory.
 1083             If <code>size</code> is zero, <code>NULL</code> is returned.
 1084           </description>
 1085         </param>
 1086       </parameters>
 1087       <errors>
 1088         <error id="JVMTI_ERROR_OUT_OF_MEMORY">
 1089           Memory request cannot be honored.
 1090         </error>
 1091         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
 1092           <paramlink id="size"></paramlink> is less than zero.
 1093         </error>
 1094       </errors>
 1095     </function>
 1096 
 1097     <function id="Deallocate" jkernel="yes" phase="any" callbacksafe="safe" impl="notrace" num="47">
 1098       <synopsis>Deallocate</synopsis>
 1099       <description>
 1100         Deallocate <code>mem</code>  using the <jvmti/> allocator.
 1101         This function should
 1102         be used to deallocate any memory allocated and returned
 1103         by a <jvmti/> function
 1104         (including memory allocated with <functionlink id="Allocate"></functionlink>).
 1105         All allocated memory must be deallocated
 1106         or the memory cannot be reclaimed.
 1107       </description>
 1108       <origin>jvmdi</origin>
 1109       <capabilities>
 1110       </capabilities>
 1111       <parameters>
 1112         <param id="mem">
 1113           <outbuf>
 1114             <uchar/>
 1115             <nullok>the call is ignored</nullok>
 1116           </outbuf>
 1117           <description>
 1118             A pointer to the beginning of the allocated memory.
 1119             Please ignore "On return, the elements are set."
 1120               <todo>keep it from generating "On return, the elements are set"</todo>
 1121           </description>
 1122         </param>
 1123       </parameters>
 1124       <errors>
 1125       </errors>
 1126     </function>
 1127   </category>
 1128 
 1129   <category id="threadCategory" label="Thread">
 1130     <intro>
 1131     </intro>
 1132 
 1133     <function id="GetThreadState" num="17">
 1134       <synopsis>Get Thread State</synopsis>
 1135       <description>
 1136         Get the state of a thread.  The state of the thread is represented by the
 1137         answers to the hierarchical set of questions below:
 1138           <ul type="circle">
 1139             <li><i>Alive?</i>
 1140               <ul>
 1141                 <li>Not alive.
 1142                   <ul type="circle">
 1143                     <li><i>Why not alive?</i>
 1144                       <ul>
 1145                         <li>New.</li>
 1146                         <li>Terminated (<datalink
 1147                             id="JVMTI_THREAD_STATE_TERMINATED"><code>JVMTI_THREAD_STATE_TERMINATED</code></datalink>)</li>
 1148                       </ul>
 1149                     </li>
 1150                   </ul>
 1151                 </li>
 1152                 <li>Alive (<datalink
 1153                     id="JVMTI_THREAD_STATE_ALIVE"><code>JVMTI_THREAD_STATE_ALIVE</code></datalink>)
 1154                   <ul type="circle">
 1155                     <li><i>Suspended?</i>
 1156                       <ul>
 1157                         <li>Suspended (<datalink
 1158                             id="JVMTI_THREAD_STATE_SUSPENDED"><code>JVMTI_THREAD_STATE_SUSPENDED</code></datalink>)</li>
 1159                         <li>Not suspended</li>
 1160                       </ul>
 1161                     </li>
 1162                     <li><i>Interrupted?</i>
 1163                       <ul>
 1164                         <li>Interrupted (<datalink
 1165                             id="JVMTI_THREAD_STATE_INTERRUPTED"><code>JVMTI_THREAD_STATE_INTERRUPTED</code></datalink>)</li>
 1166                         <li>Not interrupted.</li>
 1167                       </ul>
 1168                     </li>
 1169                     <li><i>In native?</i>
 1170                       <ul>
 1171                         <li>In native code (<datalink
 1172                             id="JVMTI_THREAD_STATE_IN_NATIVE"><code>JVMTI_THREAD_STATE_IN_NATIVE</code></datalink>)</li>
 1173                         <li>In Java programming language code</li>
 1174                       </ul>
 1175                     </li>
 1176                     <li><i>What alive state?</i>
 1177                       <ul>
 1178                         <li>Runnable (<datalink
 1179                             id="JVMTI_THREAD_STATE_RUNNABLE"><code>JVMTI_THREAD_STATE_RUNNABLE</code></datalink>)</li>
 1180                         <li>Blocked (<datalink
 1181                             id="JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER"><code>JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER</code></datalink>)</li>
 1182                         <li>Waiting (<datalink
 1183                             id="JVMTI_THREAD_STATE_WAITING"><code>JVMTI_THREAD_STATE_WAITING</code></datalink>)
 1184                           <ul type="circle">
 1185                             <li><i>Timed wait?</i>
 1186                               <ul>
 1187                                 <li>Indefinite (<datalink
 1188                                     id="JVMTI_THREAD_STATE_WAITING_INDEFINITELY"><code>JVMTI_THREAD_STATE_WAITING_INDEFINITELY</code></datalink></li>
 1189                                 <li>Timed (<datalink
 1190                                     id="JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT"><code>JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT</code></datalink>)</li>
 1191                               </ul>
 1192                             </li>
 1193                             <li><i>Why waiting?</i>
 1194                               <ul>
 1195                                 <li>Object.wait (<datalink
 1196                                     id="JVMTI_THREAD_STATE_IN_OBJECT_WAIT"><code>JVMTI_THREAD_STATE_IN_OBJECT_WAIT</code></datalink>)</li>
 1197                                 <li>LockSupport.park (<datalink
 1198                                     id="JVMTI_THREAD_STATE_PARKED"><code>JVMTI_THREAD_STATE_PARKED</code></datalink>)</li>
 1199                                 <li>Sleeping (<datalink
 1200                                     id="JVMTI_THREAD_STATE_SLEEPING"><code>JVMTI_THREAD_STATE_SLEEPING</code></datalink>)</li>
 1201                               </ul>
 1202                             </li>
 1203                           </ul>
 1204                         </li>
 1205                       </ul>
 1206                     </li>
 1207                   </ul>
 1208                 </li>
 1209               </ul>
 1210             </li>
 1211           </ul>
 1212         <p/>
 1213         The answers are represented by the following bit vector.
 1214         <constants id="jvmtiThreadState" label="Thread State Flags" kind="bits">
 1215           <constant id="JVMTI_THREAD_STATE_ALIVE" num="0x0001">
 1216             Thread is alive. Zero if thread is new (not started) or terminated.
 1217           </constant>
 1218           <constant id="JVMTI_THREAD_STATE_TERMINATED" num="0x0002">
 1219             Thread has completed execution.
 1220           </constant>
 1221           <constant id="JVMTI_THREAD_STATE_RUNNABLE" num="0x0004">
 1222             Thread is runnable.
 1223           </constant>
 1224           <constant id="JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER" num="0x0400">
 1225             Thread is waiting to enter a synchronization block/method or,
 1226             after an <code>Object.wait()</code>, waiting to re-enter a
 1227             synchronization block/method.
 1228           </constant>
 1229           <constant id="JVMTI_THREAD_STATE_WAITING" num="0x0080">
 1230             Thread is waiting.
 1231           </constant>
 1232           <constant id="JVMTI_THREAD_STATE_WAITING_INDEFINITELY" num="0x0010">
 1233             Thread is waiting without a timeout.
 1234             For example, <code>Object.wait()</code>.
 1235           </constant>
 1236           <constant id="JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT" num="0x0020">
 1237             Thread is waiting with a maximum time to wait specified.
 1238             For example, <code>Object.wait(long)</code>.
 1239           </constant>
 1240           <constant id="JVMTI_THREAD_STATE_SLEEPING" num="0x0040">
 1241             Thread is sleeping -- <code>Thread.sleep(long)</code>.
 1242           </constant>
 1243           <constant id="JVMTI_THREAD_STATE_IN_OBJECT_WAIT" num="0x0100">
 1244             Thread is waiting on an object monitor -- <code>Object.wait</code>.
 1245           </constant>
 1246           <constant id="JVMTI_THREAD_STATE_PARKED" num="0x0200">
 1247             Thread is parked, for example: <code>LockSupport.park</code>,
 1248             <code>LockSupport.parkUtil</code> and <code>LockSupport.parkNanos</code>.
 1249           </constant>
 1250           <constant id="JVMTI_THREAD_STATE_SUSPENDED" num="0x100000">
 1251             Thread suspended.
 1252             <code>java.lang.Thread.suspend()</code>
 1253             or a <jvmti/> suspend function
 1254             (such as <functionlink id="SuspendThread"></functionlink>)
 1255             has been called on the thread. If this bit
 1256             is set, the other bits refer to the thread state before suspension.
 1257           </constant>
 1258           <constant id="JVMTI_THREAD_STATE_INTERRUPTED" num="0x200000">
 1259             Thread has been interrupted.
 1260           </constant>
 1261           <constant id="JVMTI_THREAD_STATE_IN_NATIVE" num="0x400000">
 1262             Thread is in native code--that is, a native method is running
 1263             which has not called back into the VM or Java programming
 1264             language code.
 1265             <p/>
 1266             This flag is not set when running VM compiled Java programming
 1267             language code nor is it set when running VM code or
 1268             VM support code. Native VM interface functions, such as JNI and
 1269             <jvmti/> functions, may be implemented as VM code.
 1270           </constant>
 1271           <constant id="JVMTI_THREAD_STATE_VENDOR_1" num="0x10000000">
 1272             Defined by VM vendor.
 1273           </constant>
 1274           <constant id="JVMTI_THREAD_STATE_VENDOR_2" num="0x20000000">
 1275             Defined by VM vendor.
 1276           </constant>
 1277           <constant id="JVMTI_THREAD_STATE_VENDOR_3" num="0x40000000">
 1278             Defined by VM vendor.
 1279           </constant>
 1280         </constants>
 1281         The following definitions are used to convert <jvmti/> thread state
 1282         to <code>java.lang.Thread.State</code> style states.
 1283         <constants id="jvmtiJavaLangThreadState" label="java.lang.Thread.State Conversion Masks" kind="bits">
 1284           <constant id="JVMTI_JAVA_LANG_THREAD_STATE_MASK"
 1285                      num="JVMTI_THREAD_STATE_TERMINATED | JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_RUNNABLE | JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER | JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_INDEFINITELY | JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT">
 1286             Mask the state with this before comparison
 1287           </constant>
 1288           <constant id="JVMTI_JAVA_LANG_THREAD_STATE_NEW"
 1289                      num="0">
 1290             <code>java.lang.Thread.State.NEW</code>
 1291           </constant>
 1292           <constant id="JVMTI_JAVA_LANG_THREAD_STATE_TERMINATED"
 1293                      num="JVMTI_THREAD_STATE_TERMINATED">
 1294             <code>java.lang.Thread.State.TERMINATED</code>
 1295           </constant>
 1296           <constant id="JVMTI_JAVA_LANG_THREAD_STATE_RUNNABLE"
 1297                      num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_RUNNABLE">
 1298             <code>java.lang.Thread.State.RUNNABLE</code>
 1299           </constant>
 1300           <constant id="JVMTI_JAVA_LANG_THREAD_STATE_BLOCKED"
 1301                      num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER">
 1302             <code>java.lang.Thread.State.BLOCKED</code>
 1303           </constant>
 1304           <constant id="JVMTI_JAVA_LANG_THREAD_STATE_WAITING"
 1305                      num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_INDEFINITELY">
 1306             <code>java.lang.Thread.State.WAITING</code>
 1307           </constant>
 1308           <constant id="JVMTI_JAVA_LANG_THREAD_STATE_TIMED_WAITING"
 1309                      num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT">
 1310             <code>java.lang.Thread.State.TIMED_WAITING</code>
 1311           </constant>
 1312         </constants>
 1313         <b>Rules</b>
 1314         <p/>
 1315         There can be no more than one answer to a question, although there can be no
 1316         answer (because the answer is unknown, does not apply, or none of the answers is
 1317         correct).  An answer is set only when the enclosing answers match.
 1318         That is, no more than one of
 1319           <ul type="circle">
 1320               <li><code>JVMTI_THREAD_STATE_RUNNABLE</code></li>
 1321               <li><code>JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER</code></li>
 1322               <li><code>JVMTI_THREAD_STATE_WAITING</code></li>
 1323           </ul>
 1324         can be set (a <tm>J2SE</tm> compliant implementation will always set
 1325         one of these if <code>JVMTI_THREAD_STATE_ALIVE</code> is set).
 1326         And if any of these are set, the enclosing answer
 1327         <code>JVMTI_THREAD_STATE_ALIVE</code> is set.
 1328         No more than one of
 1329           <ul type="circle">
 1330               <li><code>JVMTI_THREAD_STATE_WAITING_INDEFINITELY</code></li>
 1331               <li><code>JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT</code></li>
 1332           </ul>
 1333         can be set (a <tm>J2SE</tm> compliant implementation will always set
 1334         one of these if <code>JVMTI_THREAD_STATE_WAITING</code> is set).
 1335         And if either is set, the enclosing answers
 1336         <code>JVMTI_THREAD_STATE_ALIVE</code> and
 1337         <code>JVMTI_THREAD_STATE_WAITING</code> are set.
 1338         No more than one of
 1339           <ul type="circle">
 1340               <li><code>JVMTI_THREAD_STATE_IN_OBJECT_WAIT</code></li>
 1341               <li><code>JVMTI_THREAD_STATE_PARKED</code></li>
 1342               <li><code>JVMTI_THREAD_STATE_SLEEPING</code></li>
 1343           </ul>
 1344         can be set. And if any of these is set, the enclosing answers
 1345         <code>JVMTI_THREAD_STATE_ALIVE</code> and
 1346         <code>JVMTI_THREAD_STATE_WAITING</code> are set.
 1347         Also, if <code>JVMTI_THREAD_STATE_SLEEPING</code> is set,
 1348         then <code>JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT</code> is set.
 1349         If a state <i>A</i> is implemented using the mechanism of
 1350         state <i>B</i> then it is state <i>A</i> which
 1351         is returned by this function.
 1352         For example, if <code>Thread.sleep(long)</code>
 1353         is implemented using <code>Object.wait(long)</code>
 1354         then it is still <code>JVMTI_THREAD_STATE_SLEEPING</code>
 1355         which is returned.
 1356         More than one of
 1357           <ul type="circle">
 1358               <li><code>JVMTI_THREAD_STATE_SUSPENDED</code></li>
 1359               <li><code>JVMTI_THREAD_STATE_INTERRUPTED</code></li>
 1360               <li><code>JVMTI_THREAD_STATE_IN_NATIVE</code></li>
 1361           </ul>
 1362         can be set, but if any is set,
 1363         <code>JVMTI_THREAD_STATE_ALIVE</code> is set.
 1364         <p/>
 1365         And finally,
 1366         <code>JVMTI_THREAD_STATE_TERMINATED</code> cannot be set unless
 1367         <code>JVMTI_THREAD_STATE_ALIVE</code> is not set.
 1368         <p/>
 1369         The thread state representation is designed for extension in future versions
 1370         of the specification; thread state values should be used accordingly, that is
 1371         they should not be used as ordinals.
 1372         Most queries can be made by testing a single bit, if use in a switch statement is desired,
 1373         the state bits should be masked with the interesting bits.
 1374         All bits not defined above are reserved for future use.
 1375         A VM, compliant to the current specification, must set reserved bits to zero.
 1376         An agent should ignore reserved bits --
 1377         they should not be assumed to be zero and thus should not be included in comparisons.
 1378         <p/>
 1379         <b>Examples</b>
 1380         <p/>
 1381         Note that the values below exclude reserved and vendor bits.
 1382         <p/>
 1383         The state of a thread blocked at a <code>synchronized</code>-statement would be:
 1384         <example>
 1385             JVMTI_THREAD_STATE_ALIVE + JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER
 1386         </example>
 1387         The state of a thread which hasn't started yet would be:
 1388         <example>
 1389             0
 1390         </example>
 1391         The state of a thread at a <code>Object.wait(3000)</code> would be:
 1392         <example>
 1393             JVMTI_THREAD_STATE_ALIVE + JVMTI_THREAD_STATE_WAITING +
 1394                 JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT +
 1395                 JVMTI_THREAD_STATE_MONITOR_WAITING
 1396         </example>
 1397         The state of a thread suspended while runnable would be:
 1398         <example>
 1399             JVMTI_THREAD_STATE_ALIVE + JVMTI_THREAD_STATE_RUNNABLE + JVMTI_THREAD_STATE_SUSPENDED
 1400         </example>
 1401         <p/>
 1402         <b>Testing the State</b>
 1403         <p/>
 1404         In most cases, the thread state can be determined by testing the one bit corresponding
 1405         to that question.  For example, the code to test if a thread is sleeping:
 1406         <example>
 1407         jint state;
 1408         jvmtiError err;
 1409 
 1410         err = (*jvmti)-&gt;GetThreadState(jvmti, thread, &amp;state);
 1411         if (err == JVMTI_ERROR_NONE) {
 1412            if (state &amp; JVMTI_THREAD_STATE_SLEEPING) {  ...
 1413         </example>
 1414         <p/>
 1415         For waiting (that is, in <code>Object.wait</code>, parked, or sleeping) it would be:
 1416         <example>
 1417            if (state &amp; JVMTI_THREAD_STATE_WAITING) {  ...
 1418         </example>
 1419         For some states, more than one bit will need to be tested as is the case
 1420         when testing if a thread has not yet been started:
 1421         <example>
 1422            if ((state &amp; (JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_TERMINATED)) == 0)  {  ...
 1423         </example>
 1424         To distinguish timed from untimed <code>Object.wait</code>:
 1425         <example>
 1426            if (state &amp; JVMTI_THREAD_STATE_IN_OBJECT_WAIT)  {
 1427              if (state &amp; JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT)  {
 1428                printf("in Object.wait(long timeout)\n");
 1429              } else {
 1430                printf("in Object.wait()\n");
 1431              }
 1432            }
 1433         </example>
 1434         <p/>
 1435         <b>Relationship to <code>java.lang.Thread.State</code></b>
 1436         <p/>
 1437         The thread state represented by <code>java.lang.Thread.State</code>
 1438         returned from <code>java.lang.Thread.getState()</code> is a subset of the
 1439         information returned from this function.
 1440         The corresponding <code>java.lang.Thread.State</code> can be determined
 1441         by using the provided conversion masks.
 1442         For example, this returns the name of the <code>java.lang.Thread.State</code> thread state:
 1443         <example>
 1444             err = (*jvmti)-&gt;GetThreadState(jvmti, thread, &amp;state);
 1445             abortOnError(err);
 1446             switch (state &amp; JVMTI_JAVA_LANG_THREAD_STATE_MASK) {
 1447             case JVMTI_JAVA_LANG_THREAD_STATE_NEW:
 1448               return "NEW";
 1449             case JVMTI_JAVA_LANG_THREAD_STATE_TERMINATED:
 1450               return "TERMINATED";
 1451             case JVMTI_JAVA_LANG_THREAD_STATE_RUNNABLE:
 1452               return "RUNNABLE";
 1453             case JVMTI_JAVA_LANG_THREAD_STATE_BLOCKED:
 1454               return "BLOCKED";
 1455             case JVMTI_JAVA_LANG_THREAD_STATE_WAITING:
 1456               return "WAITING";
 1457             case JVMTI_JAVA_LANG_THREAD_STATE_TIMED_WAITING:
 1458               return "TIMED_WAITING";
 1459             }
 1460         </example>
 1461       </description>
 1462       <origin>new</origin>
 1463       <capabilities>
 1464       </capabilities>
 1465       <parameters>
 1466         <param id="thread">
 1467           <jthread null="current" started="maybe" impl="noconvert"/>
 1468             <description>
 1469               The thread to query.
 1470             </description>
 1471         </param>
 1472         <param id="thread_state_ptr">
 1473           <outptr><jint/></outptr>
 1474           <description>
 1475             On return, points to state flags,
 1476             as defined by the <internallink id="jvmtiThreadState">Thread State Flags</internallink>.
 1477           </description>
 1478         </param>
 1479       </parameters>
 1480       <errors>
 1481       </errors>
 1482     </function>
 1483 
 1484     <function id="GetCurrentThread" phase="start" num="18" since="1.1">
 1485       <synopsis>Get Current Thread</synopsis>
 1486       <description>
 1487         Get the current thread.
 1488         The current thread is the Java programming language thread which has called the function.
 1489         The function may return <code>NULL</code> in the start phase if the
 1490         <internallink id="jvmtiCapabilities.can_generate_early_vmstart">
 1491         <code>can_generate_early_vmstart</code></internallink> capability is enabled
 1492         and the <code>java.lang.Thread</code> class has not been initialized yet.
 1493         <p/>
 1494         Note that most <jvmti/> functions that take a thread
 1495         as an argument will accept <code>NULL</code> to mean
 1496         the current thread.
 1497       </description>
 1498       <origin>new</origin>
 1499       <capabilities>
 1500       </capabilities>
 1501       <parameters>
 1502         <param id="thread_ptr">
 1503           <outptr><jthread/></outptr>
 1504           <description>
 1505              On return, points to the current thread, or <code>NULL</code>.
 1506           </description>
 1507         </param>
 1508       </parameters>
 1509       <errors>
 1510       </errors>
 1511     </function>
 1512 
 1513     <function id="GetAllThreads" num="4">
 1514       <synopsis>Get All Threads</synopsis>
 1515       <description>
 1516         Get all live threads.
 1517         The threads are Java programming language threads;
 1518         that is, threads that are attached to the VM.
 1519         A thread is live if <code>java.lang.Thread.isAlive()</code>
 1520         would return <code>true</code>, that is, the thread has
 1521         been started and has not yet died.
 1522         The universe of threads is determined by the context of the <jvmti/>
 1523         environment, which typically is all threads attached to the VM.
 1524         Note that this includes <jvmti/> agent threads
 1525         (see <functionlink id="RunAgentThread"/>).
 1526       </description>
 1527       <origin>jvmdi</origin>
 1528       <capabilities>
 1529       </capabilities>
 1530       <parameters>
 1531         <param id="threads_count_ptr">
 1532           <outptr><jint/></outptr>
 1533           <description>
 1534             On return, points to the number of running threads.
 1535           </description>
 1536         </param>
 1537         <param id="threads_ptr">
 1538           <allocbuf outcount="threads_count_ptr"><jthread/></allocbuf>
 1539             <description>
 1540               On return, points to an array of references, one
 1541               for each running thread.
 1542             </description>
 1543         </param>
 1544       </parameters>
 1545       <errors>
 1546       </errors>
 1547     </function>
 1548 
 1549     <function id="SuspendThread" num="5">
 1550       <synopsis>Suspend Thread</synopsis>
 1551       <description>
 1552         Suspend the specified thread. If the calling thread is specified,
 1553         this function will not return until some other thread calls
 1554         <functionlink id="ResumeThread"></functionlink>.
 1555         If the thread is currently suspended, this function
 1556         does nothing and returns an error.
 1557       </description>
 1558       <origin>jvmdi</origin>
 1559       <capabilities>
 1560         <required id="can_suspend"></required>
 1561       </capabilities>
 1562       <parameters>
 1563         <param id="thread">
 1564           <jthread null="current"/>
 1565             <description>
 1566               The thread to suspend.
 1567             </description>
 1568         </param>
 1569       </parameters>
 1570       <errors>
 1571         <error id="JVMTI_ERROR_THREAD_SUSPENDED">
 1572           Thread already suspended.
 1573         </error>
 1574       </errors>
 1575     </function>
 1576 
 1577     <elide>
 1578     <function id="SuspendAllThreads" num="101">
 1579       <synopsis>Suspend All Threads</synopsis>
 1580       <description>
 1581         <issue>
 1582             There has been no explicit call for this function, and it will
 1583             thus be removed if there is no interest.
 1584         </issue>
 1585         Suspend all live threads except:
 1586         <ul>
 1587           <li>already suspended threads</li>
 1588           <li>those listed in <paramlink id="except_list"></paramlink></li>
 1589           <li>certain system (non application) threads, as determined
 1590             by the VM implementation</li>
 1591         </ul>
 1592         The threads are Java programming language threads;
 1593         native threads which are not attached to the VM are not
 1594         Java programming language threads.
 1595         A thread is live if <code>java.lang.Thread.isAlive()</code>
 1596         would return <code>true</code>, that is, the thread has
 1597         been started and has not yet died.
 1598         The universe of threads is determined
 1599         by the context of the <jvmti/>
 1600         environment, which, typically, is all threads attached to the VM,
 1601         except critical VM internal threads and <jvmti/> agent threads
 1602         (see <functionlink id="RunAgentThread"/>).
 1603         <p/>
 1604         If the calling thread is specified,
 1605         all other threads are suspended first then the caller thread is suspended -
 1606         this function will not return until some other thread calls
 1607         <functionlink id="ResumeThread"></functionlink>.
 1608         <p/>
 1609         The list of actually
 1610         suspended threads is returned in
 1611         <paramlink id="suspended_list_ptr"></paramlink>.
 1612         Suspension is as defined in <functionlink id="SuspendThread"></functionlink>.
 1613         <functionlink id="ResumeThreadList"></functionlink>
 1614         can be used to resume the suspended threads.
 1615       </description>
 1616       <origin>new</origin>
 1617       <capabilities>
 1618         <required id="can_suspend"></required>
 1619       </capabilities>
 1620       <parameters>
 1621         <param id="except_count">
 1622           <jint min="0"/>
 1623           <description>
 1624             The number of threads in the list of threads not to be suspended.
 1625           </description>
 1626         </param>
 1627         <param id="except_list">
 1628             <inbuf incount="except_count">
 1629               <jthread/>
 1630               <nullok>not an error if <code>except_count == 0</code></nullok>
 1631             </inbuf>
 1632             <description>
 1633               The list of threads not to be suspended.
 1634             </description>
 1635         </param>
 1636         <param id="suspended_count_ptr">
 1637           <outptr><jint/></outptr>
 1638           <description>
 1639             On return, points to the number of threads suspended by this call.
 1640           </description>
 1641         </param>
 1642         <param id="suspended_list_ptr">
 1643           <allocbuf outcount="suspended_count_ptr"><jthread/></allocbuf>
 1644             <description>
 1645               On return, points to an array of references, one
 1646               for each thread suspended.
 1647             </description>
 1648         </param>
 1649       </parameters>
 1650       <errors>
 1651         <error id="JVMTI_ERROR_INVALID_THREAD">
 1652           A thread in <paramlink id="except_list"></paramlink> was invalid.
 1653         </error>
 1654         <error id="JVMTI_ERROR_NULL_POINTER">
 1655           Both <paramlink id="except_list"></paramlink> was <code>NULL</code>
 1656           and <paramlink id="except_count"></paramlink> was non-zero.
 1657         </error>
 1658       </errors>
 1659     </function>
 1660     </elide>
 1661 
 1662     <function id="SuspendThreadList" num="92">
 1663       <synopsis>Suspend Thread List</synopsis>
 1664       <description>
 1665         Suspend the <paramlink id="request_count"></paramlink>
 1666         threads specified in the
 1667         <paramlink id="request_list"></paramlink> array.
 1668         Threads may be resumed with
 1669         <functionlink id="ResumeThreadList"></functionlink> or
 1670         <functionlink id="ResumeThread"></functionlink>.
 1671         If the calling thread is specified in the
 1672         <paramlink id="request_list"></paramlink> array, this function will
 1673         not return until some other thread resumes it.
 1674         Errors encountered in the suspension of a thread
 1675         are returned in the <paramlink id="results"></paramlink>
 1676         array, <b>not</b> in the return value of this function.
 1677         Threads that are currently suspended do not change state.
 1678       </description>
 1679       <origin>jvmdi</origin>
 1680       <capabilities>
 1681         <required id="can_suspend"></required>
 1682       </capabilities>
 1683       <parameters>
 1684         <param id="request_count">
 1685           <jint min="0"/>
 1686           <description>
 1687             The number of threads to suspend.
 1688           </description>
 1689         </param>
 1690         <param id="request_list">
 1691           <inbuf incount="request_count"><jthread/></inbuf>
 1692             <description>
 1693               The list of threads to suspend.
 1694             </description>
 1695         </param>
 1696         <param id="results">
 1697           <outbuf incount="request_count"><enum>jvmtiError</enum></outbuf>
 1698           <description>
 1699             An agent supplied array of
 1700             <paramlink id="request_count"></paramlink> elements.
 1701             On return, filled with the error code for
 1702             the suspend of the corresponding thread.
 1703             The error code will be
 1704             <errorlink id="JVMTI_ERROR_NONE"></errorlink>
 1705             if the thread was suspended by this call.
 1706             Possible error codes are those specified
 1707             for <functionlink id="SuspendThread"></functionlink>.
 1708           </description>
 1709         </param>
 1710       </parameters>
 1711       <errors>
 1712       </errors>
 1713     </function>
 1714 
 1715     <function id="ResumeThread" num="6">
 1716       <synopsis>Resume Thread</synopsis>
 1717       <description>
 1718         Resume a suspended thread.
 1719         Any threads currently suspended through
 1720         a <jvmti/> suspend function (eg.
 1721         <functionlink id="SuspendThread"></functionlink>)
 1722         or <code>java.lang.Thread.suspend()</code>
 1723         will resume execution;
 1724         all other threads are unaffected.
 1725       </description>
 1726       <origin>jvmdi</origin>
 1727       <capabilities>
 1728         <required id="can_suspend"></required>
 1729       </capabilities>
 1730       <parameters>
 1731         <param id="thread">
 1732           <jthread/>
 1733             <description>
 1734               The thread to resume.
 1735             </description>
 1736         </param>
 1737       </parameters>
 1738       <errors>
 1739         <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
 1740           Thread was not suspended.
 1741         </error>
 1742         <error id="JVMTI_ERROR_INVALID_TYPESTATE">
 1743           The state of the thread has been modified, and is now inconsistent.
 1744         </error>
 1745       </errors>
 1746     </function>
 1747 
 1748     <function id="ResumeThreadList" num="93">
 1749       <synopsis>Resume Thread List</synopsis>
 1750       <description>
 1751         Resume the <paramlink id="request_count"></paramlink>
 1752         threads specified in the
 1753         <paramlink id="request_list"></paramlink> array.
 1754         Any thread suspended through
 1755         a <jvmti/> suspend function (eg.
 1756         <functionlink id="SuspendThreadList"></functionlink>)
 1757         or <code>java.lang.Thread.suspend()</code>
 1758         will resume execution.
 1759       </description>
 1760       <origin>jvmdi</origin>
 1761       <capabilities>
 1762         <required id="can_suspend"></required>
 1763       </capabilities>
 1764       <parameters>
 1765         <param id="request_count">
 1766           <jint min="0"/>
 1767           <description>
 1768             The number of threads to resume.
 1769           </description>
 1770         </param>
 1771         <param id="request_list">
 1772           <inbuf incount="request_count"><jthread/></inbuf>
 1773             <description>
 1774               The threads to resume.
 1775             </description>
 1776         </param>
 1777         <param id="results">
 1778           <outbuf incount="request_count"><enum>jvmtiError</enum></outbuf>
 1779           <description>
 1780             An agent supplied array of
 1781             <paramlink id="request_count"></paramlink> elements.
 1782             On return, filled with the error code for
 1783             the resume of the corresponding thread.
 1784             The error code will be
 1785             <errorlink id="JVMTI_ERROR_NONE"></errorlink>
 1786             if the thread was suspended by this call.
 1787             Possible error codes are those specified
 1788             for <functionlink id="ResumeThread"></functionlink>.
 1789           </description>
 1790         </param>
 1791       </parameters>
 1792       <errors>
 1793       </errors>
 1794     </function>
 1795 
 1796     <function id="StopThread" num="7">
 1797       <synopsis>Stop Thread</synopsis>
 1798       <description>
 1799         Send the specified asynchronous exception to the specified thread.
 1800         Normally, this function is used to kill the specified thread with an
 1801         instance of the exception <code>ThreadDeath</code>, similar to
 1802         <code>java.lang.Thread.stop</code>.
 1803       </description>
 1804       <origin>jvmdi</origin>
 1805       <capabilities>
 1806         <required id="can_signal_thread"></required>
 1807       </capabilities>
 1808       <parameters>
 1809         <param id="thread">
 1810           <jthread/>
 1811             <description>
 1812               The thread to stop.
 1813             </description>
 1814         </param>
 1815         <param id="exception">
 1816           <jobject/>
 1817             <description>
 1818               The asynchronous exception object.
 1819             </description>
 1820         </param>
 1821       </parameters>
 1822       <errors>
 1823       </errors>
 1824     </function>
 1825 
 1826     <function id="InterruptThread" num="8">
 1827       <synopsis>Interrupt Thread</synopsis>
 1828       <description>
 1829         Interrupt the specified thread
 1830         (similar to <code>java.lang.Thread.interrupt</code>).
 1831       </description>
 1832       <origin>jvmdi</origin>
 1833       <capabilities>
 1834         <required id="can_signal_thread"></required>
 1835       </capabilities>
 1836       <parameters>
 1837         <param id="thread">
 1838           <jthread impl="noconvert"/>
 1839             <description>
 1840               The thread to interrupt.
 1841             </description>
 1842         </param>
 1843       </parameters>
 1844       <errors>
 1845       </errors>
 1846     </function>
 1847 
 1848     <function id="GetThreadInfo" num="9">
 1849       <synopsis>Get Thread Info</synopsis>
 1850       <typedef id="jvmtiThreadInfo" label="Thread information structure">
 1851         <field id="name">
 1852           <allocfieldbuf><char/></allocfieldbuf>
 1853           <description>
 1854             The thread name, encoded as a
 1855             <internallink id="mUTF">modified UTF-8</internallink> string.
 1856           </description>
 1857         </field>
 1858         <field id="priority">
 1859           <jint/>
 1860           <description>
 1861             The thread priority.  See the thread priority constants:
 1862             <datalink id="jvmtiThreadPriority"></datalink>.
 1863           </description>
 1864         </field>
 1865         <field id="is_daemon">
 1866           <jboolean/>
 1867           <description>
 1868             Is this a daemon thread?
 1869           </description>
 1870         </field>
 1871         <field id="thread_group">
 1872           <jthreadGroup/>
 1873           <description>
 1874             The thread group to which this thread belongs.
 1875             <code>NULL</code> if the thread has died.
 1876           </description>
 1877         </field>
 1878         <field id="context_class_loader">
 1879           <jobject/>
 1880             <description>
 1881               The context class loader associated with this thread.
 1882             </description>
 1883         </field>
 1884       </typedef>
 1885       <description>
 1886         Get thread information. The fields of the <datalink id="jvmtiThreadInfo"/> structure
 1887         are filled in with details of the specified thread.
 1888       </description>
 1889       <origin>jvmdi</origin>
 1890       <capabilities>
 1891       </capabilities>
 1892       <parameters>
 1893         <param id="thread">
 1894           <jthread null="current" impl="noconvert" started="maybe"/>
 1895             <description>
 1896               The thread to query.
 1897             </description>
 1898         </param>
 1899         <param id="info_ptr">
 1900           <outptr><struct>jvmtiThreadInfo</struct></outptr>
 1901           <description>
 1902             On return, filled with information describing the specified thread.
 1903           </description>
 1904         </param>
 1905       </parameters>
 1906       <errors>
 1907       </errors>
 1908     </function>
 1909 
 1910     <function id="GetOwnedMonitorInfo" num="10">
 1911       <synopsis>Get Owned Monitor Info</synopsis>
 1912       <description>
 1913         Get information about the monitors owned by the
 1914         specified thread.
 1915       </description>
 1916       <origin>jvmdiClone</origin>
 1917       <capabilities>
 1918         <required id="can_get_owned_monitor_info"></required>
 1919       </capabilities>
 1920       <parameters>
 1921         <param id="thread">
 1922           <jthread null="current"/>
 1923             <description>
 1924               The thread to query.
 1925             </description>
 1926         </param>
 1927         <param id="owned_monitor_count_ptr">
 1928           <outptr><jint/></outptr>
 1929           <description>
 1930             The number of monitors returned.
 1931           </description>
 1932         </param>
 1933         <param id="owned_monitors_ptr">
 1934           <allocbuf outcount="owned_monitor_count_ptr"><jobject/></allocbuf>
 1935             <description>
 1936               The array of owned monitors.
 1937             </description>
 1938         </param>
 1939       </parameters>
 1940       <errors>
 1941       </errors>
 1942     </function>
 1943 
 1944     <function id="GetOwnedMonitorStackDepthInfo" num="153" since="1.1">
 1945       <synopsis>Get Owned Monitor Stack Depth Info</synopsis>
 1946       <typedef id="jvmtiMonitorStackDepthInfo"
 1947                label="Monitor stack depth information structure">
 1948         <field id="monitor">
 1949           <jobject/>
 1950             <description>
 1951               The owned monitor.
 1952             </description>
 1953         </field>
 1954         <field id="stack_depth">
 1955           <jint/>
 1956           <description>
 1957             The stack depth.  Corresponds to the stack depth used in the
 1958             <internallink id="stack">Stack Frame functions</internallink>.
 1959             That is, zero is the current frame, one is the frame which
 1960             called the current frame. And it is negative one if the
 1961             implementation cannot determine the stack depth (e.g., for
 1962             monitors acquired by JNI <code>MonitorEnter</code>).
 1963           </description>
 1964         </field>
 1965       </typedef>
 1966       <description>
 1967         Get information about the monitors owned by the
 1968         specified thread and the depth of the stack frame which locked them.
 1969       </description>
 1970       <origin>new</origin>
 1971       <capabilities>
 1972         <required id="can_get_owned_monitor_stack_depth_info"></required>
 1973       </capabilities>
 1974       <parameters>
 1975         <param id="thread">
 1976           <jthread null="current"/>
 1977             <description>
 1978               The thread to query.
 1979             </description>
 1980         </param>
 1981         <param id="monitor_info_count_ptr">
 1982           <outptr><jint/></outptr>
 1983           <description>
 1984             The number of monitors returned.
 1985           </description>
 1986         </param>
 1987         <param id="monitor_info_ptr">
 1988           <allocbuf outcount="monitor_info_count_ptr">
 1989             <struct>jvmtiMonitorStackDepthInfo</struct>
 1990           </allocbuf>
 1991           <description>
 1992             The array of owned monitor depth information.
 1993           </description>
 1994         </param>
 1995       </parameters>
 1996       <errors>
 1997       </errors>
 1998     </function>
 1999 
 2000     <function id="GetCurrentContendedMonitor" num="11">
 2001       <synopsis>Get Current Contended Monitor</synopsis>
 2002       <description>
 2003         Get the object, if any, whose monitor the specified thread is waiting to
 2004         enter or waiting to regain through <code>java.lang.Object.wait</code>.
 2005       </description>
 2006       <origin>jvmdi</origin>
 2007       <capabilities>
 2008         <required id="can_get_current_contended_monitor"></required>
 2009       </capabilities>
 2010       <parameters>
 2011         <param id="thread">
 2012           <jthread null="current"/>
 2013             <description>
 2014               The thread to query.
 2015             </description>
 2016         </param>
 2017         <param id="monitor_ptr">
 2018           <outptr><jobject/></outptr>
 2019             <description>
 2020               On return, filled with the current contended monitor, or
 2021               NULL if there is none.
 2022             </description>
 2023         </param>
 2024       </parameters>
 2025       <errors>
 2026       </errors>
 2027     </function>
 2028 
 2029     <callback id="jvmtiStartFunction">
 2030       <void/>
 2031       <synopsis>Agent Start Function</synopsis>
 2032       <description>
 2033         Agent supplied callback function.
 2034         This function is the entry point for an agent thread
 2035         started with
 2036         <functionlink id="RunAgentThread"></functionlink>.
 2037       </description>
 2038       <parameters>
 2039           <param id="jvmti_env">
 2040             <outptr>
 2041               <struct>jvmtiEnv</struct>
 2042             </outptr>
 2043             <description>
 2044               The <jvmti/> environment.
 2045             </description>
 2046           </param>
 2047           <param id="jni_env">
 2048             <outptr>
 2049               <struct>JNIEnv</struct>
 2050             </outptr>
 2051             <description>
 2052               The JNI environment.
 2053             </description>
 2054           </param>
 2055           <param id="arg">
 2056             <outptr>
 2057               <void/>
 2058             </outptr>
 2059               <description>
 2060                 The <code>arg</code> parameter passed to
 2061                 <functionlink id="RunAgentThread"></functionlink>.
 2062               </description>
 2063           </param>
 2064       </parameters>
 2065     </callback>
 2066 
 2067     <function id="RunAgentThread" num="12">
 2068       <synopsis>Run Agent Thread</synopsis>
 2069       <description>
 2070         Starts the execution of an agent thread. with the specified native function.
 2071         The parameter <paramlink id="arg"></paramlink> is forwarded on to the
 2072         <functionlink id="jvmtiStartFunction">start function</functionlink>
 2073         (specified with <paramlink id="proc"></paramlink>) as its single argument.
 2074         This function allows the creation of agent threads
 2075         for handling communication with another process or for handling events
 2076         without the need to load a special subclass of <code>java.lang.Thread</code> or
 2077         implementer of <code>java.lang.Runnable</code>.
 2078         Instead, the created thread can run entirely in native code.
 2079         However, the created thread does require a newly created instance
 2080         of <code>java.lang.Thread</code> (referenced by the argument <code>thread</code>) to
 2081         which it will be associated.
 2082         The thread object can be created with JNI calls.
 2083         <p/>
 2084         The following common thread priorities are provided for your convenience:
 2085         <constants id="jvmtiThreadPriority" label="Thread Priority Constants" kind="const">
 2086           <constant id="JVMTI_THREAD_MIN_PRIORITY" num="1">
 2087             Minimum possible thread priority
 2088           </constant>
 2089           <constant id="JVMTI_THREAD_NORM_PRIORITY" num="5">
 2090             Normal thread priority
 2091           </constant>
 2092           <constant id="JVMTI_THREAD_MAX_PRIORITY" num="10">
 2093             Maximum possible thread priority
 2094           </constant>
 2095         </constants>
 2096         <p/>
 2097         The new thread is started as a daemon thread with the specified
 2098         <paramlink id="priority"></paramlink>.
 2099         If enabled, a <eventlink id="ThreadStart"/> event will be sent.
 2100         <p/>
 2101         Since the thread has been started, the thread will be live when this function
 2102         returns, unless the thread has died immediately.
 2103         <p/>
 2104         The thread group of the thread is ignored -- specifically, the thread is not
 2105         added to the thread group and the thread is not seen on queries of the thread
 2106         group at either the Java programming language or <jvmti/> levels.
 2107         <p/>
 2108         The thread is not visible to Java programming language queries but is
 2109         included in <jvmti/> queries (for example,
 2110         <functionlink id="GetAllThreads"/> and
 2111         <functionlink id="GetAllStackTraces"/>).
 2112         <p/>
 2113         Upon execution of <code>proc</code>, the new thread will be attached to the
 2114         VM -- see the JNI documentation on
 2115         <externallink id="jni/invocation.html#attaching-to-the-vm"
 2116                       >Attaching to the VM</externallink>.
 2117       </description>
 2118       <origin>jvmdiClone</origin>
 2119       <capabilities>
 2120       </capabilities>
 2121       <parameters>
 2122         <param id="thread">
 2123           <jthread impl="noconvert" started="no"/>
 2124             <description>
 2125               The thread to run.
 2126             </description>
 2127         </param>
 2128         <param id="proc">
 2129           <ptrtype>
 2130             <struct>jvmtiStartFunction</struct>
 2131           </ptrtype>
 2132           <description>
 2133             The start function.
 2134           </description>
 2135         </param>
 2136         <param id="arg">
 2137           <inbuf>
 2138             <void/>
 2139             <nullok><code>NULL</code> is passed to the start function</nullok>
 2140           </inbuf>
 2141           <description>
 2142             The argument to the start function.
 2143           </description>
 2144         </param>
 2145         <param id="priority">
 2146           <jint/>
 2147           <description>
 2148             The priority of the started thread. Any thread
 2149             priority allowed by <code>java.lang.Thread.setPriority</code> can be used including
 2150             those in <datalink id="jvmtiThreadPriority"></datalink>.
 2151           </description>
 2152         </param>
 2153       </parameters>
 2154       <errors>
 2155         <error id="JVMTI_ERROR_INVALID_PRIORITY">
 2156             <paramlink id="priority"/> is less than
 2157             <datalink id="JVMTI_THREAD_MIN_PRIORITY"/>
 2158               or greater than
 2159             <datalink id="JVMTI_THREAD_MAX_PRIORITY"/>
 2160         </error>
 2161       </errors>
 2162     </function>
 2163 
 2164     <function id="SetThreadLocalStorage" jkernel="yes" impl="notrace" phase="start" num="103">
 2165       <synopsis>Set Thread Local Storage</synopsis>
 2166       <description>
 2167         The VM stores a pointer value associated with each environment-thread
 2168         pair. This pointer value is called <i>thread-local storage</i>.
 2169         This value is <code>NULL</code> unless set with this function.
 2170         Agents can allocate memory in which they store thread specific
 2171         information. By setting thread-local storage it can then be
 2172         accessed with
 2173         <functionlink id="GetThreadLocalStorage"></functionlink>.
 2174         <p/>
 2175         This function is called by the agent to set the value of the <jvmti/>
 2176         thread-local storage. <jvmti/> supplies to the agent a pointer-size
 2177         thread-local storage that can be used to record per-thread
 2178         information.
 2179       </description>
 2180       <origin>jvmpi</origin>
 2181       <capabilities>
 2182       </capabilities>
 2183       <parameters>
 2184         <param id="thread">
 2185           <jthread null="current"/>
 2186             <description>
 2187               Store to this thread.
 2188             </description>
 2189         </param>
 2190         <param id="data">
 2191           <inbuf>
 2192             <void/>
 2193             <nullok>value is set to <code>NULL</code></nullok>
 2194           </inbuf>
 2195           <description>
 2196             The value to be entered into the thread-local storage.
 2197           </description>
 2198         </param>
 2199       </parameters>
 2200       <errors>
 2201       </errors>
 2202     </function>
 2203 
 2204     <function id="GetThreadLocalStorage" jkernel="yes" impl="innative notrace" phase="start" num="102">
 2205       <synopsis>Get Thread Local Storage</synopsis>
 2206       <description>
 2207         Called by the agent to get the value of the <jvmti/> thread-local
 2208         storage.
 2209       </description>
 2210       <origin>jvmpi</origin>
 2211       <capabilities>
 2212       </capabilities>
 2213       <parameters>
 2214         <param id="thread">
 2215           <jthread null="current" impl="noconvert"/>
 2216             <description>
 2217               Retrieve from this thread.
 2218             </description>
 2219         </param>
 2220         <param id="data_ptr">
 2221           <agentbuf><void/></agentbuf>
 2222           <description>
 2223             Pointer through which the value of the thread local
 2224             storage is returned.
 2225             If thread-local storage has not been set with
 2226             <functionlink id="SetThreadLocalStorage"></functionlink> the returned
 2227             pointer is <code>NULL</code>.
 2228           </description>
 2229         </param>
 2230       </parameters>
 2231       <errors>
 2232       </errors>
 2233     </function>
 2234 
 2235   </category>
 2236 
 2237   <category id="thread_groups" label="Thread Group">
 2238     <intro>
 2239     </intro>
 2240 
 2241     <function id="GetTopThreadGroups" num="13">
 2242       <synopsis>Get Top Thread Groups</synopsis>
 2243       <description>
 2244         Return all top-level (parentless) thread groups in the VM.
 2245       </description>
 2246       <origin>jvmdi</origin>
 2247       <capabilities>
 2248       </capabilities>
 2249       <parameters>
 2250         <param id="group_count_ptr">
 2251           <outptr><jint/></outptr>
 2252           <description>
 2253             On return, points to the number of top-level thread groups.
 2254           </description>
 2255         </param>
 2256         <param id="groups_ptr">
 2257           <allocbuf outcount="group_count_ptr"><jthreadGroup/></allocbuf>
 2258             <description>
 2259               On return, refers to a pointer to the top-level thread group array.
 2260             </description>
 2261         </param>
 2262       </parameters>
 2263       <errors>
 2264       </errors>
 2265     </function>
 2266 
 2267     <function id="GetThreadGroupInfo" num="14">
 2268       <synopsis>Get Thread Group Info</synopsis>
 2269       <typedef id="jvmtiThreadGroupInfo" label="Thread group information structure">
 2270         <field id="parent">
 2271           <jthreadGroup/>
 2272           <description>
 2273             The parent thread group.
 2274           </description>
 2275         </field>
 2276         <field id="name">
 2277           <allocfieldbuf><char/></allocfieldbuf>
 2278           <description>
 2279             The thread group's name, encoded as a
 2280             <internallink id="mUTF">modified UTF-8</internallink> string.
 2281           </description>
 2282         </field>
 2283         <field id="max_priority">
 2284           <jint/>
 2285           <description>
 2286             The maximum priority for this thread group.
 2287           </description>
 2288         </field>
 2289         <field id="is_daemon">
 2290           <jboolean/>
 2291           <description>
 2292             Is this a daemon thread group?
 2293           </description>
 2294         </field>
 2295       </typedef>
 2296       <description>
 2297         Get information about the thread group. The fields of the
 2298         <functionlink id="jvmtiThreadGroupInfo"></functionlink> structure
 2299         are filled in with details of the specified thread group.
 2300       </description>
 2301       <origin>jvmdi</origin>
 2302       <capabilities>
 2303       </capabilities>
 2304       <parameters>
 2305         <param id="group">
 2306           <jthreadGroup/>
 2307           <description>
 2308             The thread group to query.
 2309           </description>
 2310         </param>
 2311         <param id="info_ptr">
 2312           <outptr><struct>jvmtiThreadGroupInfo</struct></outptr>
 2313           <description>
 2314             On return, filled with information describing the specified
 2315             thread group.
 2316           </description>
 2317         </param>
 2318       </parameters>
 2319       <errors>
 2320       </errors>
 2321     </function>
 2322 
 2323     <function id="GetThreadGroupChildren" num="15">
 2324       <synopsis>Get Thread Group Children</synopsis>
 2325       <description>
 2326         Get the live threads and active subgroups in this thread group.
 2327       </description>
 2328       <origin>jvmdi</origin>
 2329       <capabilities>
 2330       </capabilities>
 2331       <parameters>
 2332         <param id="group">
 2333           <jthreadGroup/>
 2334           <description>
 2335             The group to query.
 2336           </description>
 2337         </param>
 2338         <param id="thread_count_ptr">
 2339           <outptr><jint/></outptr>
 2340           <description>
 2341             On return, points to the number of live threads in this thread group.
 2342           </description>
 2343         </param>
 2344         <param id="threads_ptr">
 2345           <allocbuf outcount="thread_count_ptr"><jthread/></allocbuf>
 2346             <description>
 2347               On return, points to an array of the live threads in this thread group.
 2348             </description>
 2349         </param>
 2350         <param id="group_count_ptr">
 2351           <outptr><jint/></outptr>
 2352           <description>
 2353             On return, points to the number of active child thread groups
 2354           </description>
 2355         </param>
 2356         <param id="groups_ptr">
 2357           <allocbuf outcount="group_count_ptr"><jthreadGroup/></allocbuf>
 2358             <description>
 2359               On return, points to an array of the active child thread groups.
 2360             </description>
 2361         </param>
 2362       </parameters>
 2363       <errors>
 2364       </errors>
 2365     </function>
 2366   </category>
 2367 
 2368   <category id="stack" label="Stack Frame">
 2369     <intro>
 2370         These functions provide information about the stack of a thread.
 2371         Stack frames are referenced by depth.
 2372         The frame at depth zero is the current frame.
 2373         <p/>
 2374         Stack frames are as described in
 2375         <vmspec chapter="3.6"/>,
 2376         That is, they correspond to method
 2377         invocations (including native methods) but do not correspond to platform native or
 2378         VM internal frames.
 2379         <p/>
 2380         A <jvmti/> implementation may use method invocations to launch a thread and
 2381         the corresponding frames may be included in the stack as presented by these functions --
 2382         that is, there may be frames shown
 2383         deeper than <code>main()</code> and <code>run()</code>.
 2384         However this presentation must be consistent across all <jvmti/> functionality which
 2385         uses stack frames or stack depth.
 2386     </intro>
 2387 
 2388       <typedef id="jvmtiFrameInfo" label="Stack frame information structure">
 2389         <description>
 2390           Information about a stack frame is returned in this structure.
 2391         </description>
 2392         <field id="method">
 2393           <jmethodID/>
 2394             <description>
 2395               The method executing in this frame.
 2396             </description>
 2397         </field>
 2398         <field id="location">
 2399           <jlocation/>
 2400           <description>
 2401             The index of the instruction executing in this frame.
 2402             <code>-1</code> if the frame is executing a native method.
 2403           </description>
 2404         </field>
 2405       </typedef>
 2406 
 2407       <typedef id="jvmtiStackInfo" label="Stack information structure">
 2408         <description>
 2409           Information about a set of stack frames is returned in this structure.
 2410         </description>
 2411         <field id="thread">
 2412           <jthread/>
 2413           <description>
 2414             On return, the thread traced.
 2415           </description>
 2416         </field>
 2417         <field id="state">
 2418           <jint/>
 2419           <description>
 2420             On return, the thread state. See <functionlink id="GetThreadState"></functionlink>.
 2421           </description>
 2422         </field>
 2423         <field id="frame_buffer">
 2424           <outbuf incount="max_frame_count">
 2425             <struct>jvmtiFrameInfo</struct>
 2426           </outbuf>
 2427             <description>
 2428               On return, this agent allocated buffer is filled
 2429               with stack frame information.
 2430             </description>
 2431         </field>
 2432         <field id="frame_count">
 2433           <jint/>
 2434           <description>
 2435             On return, the number of records filled into
 2436             <code>frame_buffer</code>.
 2437             This will be
 2438             min(<code>max_frame_count</code>, <i>stackDepth</i>).
 2439           </description>
 2440         </field>
 2441       </typedef>
 2442 
 2443     <function id="GetStackTrace" num="104">
 2444       <synopsis>Get Stack Trace</synopsis>
 2445       <description>
 2446         Get information about the stack of a thread.
 2447         If <paramlink id="max_frame_count"></paramlink> is less than the depth of the stack,
 2448         the <paramlink id="max_frame_count"></paramlink> topmost frames are returned,
 2449         otherwise the entire stack is returned.
 2450         The topmost frames, those most recently invoked, are at the beginning of the returned buffer.
 2451         <p/>
 2452         The following example causes up to five of the topmost frames
 2453         to be returned and (if there are any frames) the currently
 2454         executing method name to be printed.
 2455         <example>
 2456 jvmtiFrameInfo frames[5];
 2457 jint count;
 2458 jvmtiError err;
 2459 
 2460 err = (*jvmti)-&gt;GetStackTrace(jvmti, aThread, 0, 5,
 2461                                frames, &amp;count);
 2462 if (err == JVMTI_ERROR_NONE &amp;&amp; count &gt;= 1) {
 2463    char *methodName;
 2464    err = (*jvmti)-&gt;GetMethodName(jvmti, frames[0].method,
 2465                        &amp;methodName, NULL, NULL);
 2466    if (err == JVMTI_ERROR_NONE) {
 2467       printf("Executing method: %s", methodName);
 2468    }
 2469 }
 2470         </example>
 2471         <todo>
 2472           check example code.
 2473         </todo>
 2474         <p/>
 2475         The <paramlink id="thread"></paramlink> need not be suspended
 2476         to call this function.
 2477         <p/>
 2478         The <functionlink id="GetLineNumberTable"></functionlink>
 2479         function can be used to map locations to line numbers. Note that
 2480         this mapping can be done lazily.
 2481       </description>
 2482       <origin>jvmpi</origin>
 2483       <capabilities>
 2484       </capabilities>
 2485       <parameters>
 2486         <param id="thread">
 2487           <jthread null="current"/>
 2488             <description>
 2489               Fetch the stack trace of this thread.
 2490             </description>
 2491         </param>
 2492         <param id="start_depth">
 2493           <jint/>
 2494           <description>
 2495             Begin retrieving frames at this depth.
 2496             If non-negative, count from the current frame,
 2497             the first frame retrieved is at depth <code>start_depth</code>.
 2498             For example, if zero, start from the current frame; if one, start from the
 2499             caller of the current frame; if two, start from the caller of the
 2500             caller of the current frame; and so on.
 2501             If negative, count from below the oldest frame,
 2502             the first frame retrieved is at depth <i>stackDepth</i><code> + start_depth</code>,
 2503             where <i>stackDepth</i> is the count of frames on the stack.
 2504             For example, if negative one, only the oldest frame is retrieved;
 2505             if negative two, start from the frame called by the oldest frame.
 2506           </description>
 2507         </param>
 2508         <param id="max_frame_count">
 2509           <jint min="0"/>
 2510           <description>
 2511             The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve.
 2512           </description>
 2513         </param>
 2514         <param id="frame_buffer">
 2515           <outbuf incount="max_frame_count" outcount="count_ptr">
 2516             <struct>jvmtiFrameInfo</struct>
 2517           </outbuf>
 2518             <description>
 2519               On return, this agent allocated buffer is filled
 2520               with stack frame information.
 2521             </description>
 2522         </param>
 2523         <param id="count_ptr">
 2524           <outptr><jint/></outptr>
 2525           <description>
 2526             On return, points to the number of records filled in.
 2527             For non-negative <code>start_depth</code>, this will be
 2528             min(<code>max_frame_count</code>, <i>stackDepth</i><code> - start_depth</code>).
 2529             For negative <code>start_depth</code>, this will be
 2530             min(<code>max_frame_count</code>, <code>-start_depth</code>).
 2531           </description>
 2532         </param>
 2533       </parameters>
 2534       <errors>
 2535         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
 2536           <paramlink id="start_depth"/> is positive and greater than or equal to <i>stackDepth</i>.
 2537           Or <paramlink id="start_depth"/> is negative and less than <i>-stackDepth</i>.
 2538         </error>
 2539       </errors>
 2540     </function>
 2541 
 2542 
 2543     <function id="GetAllStackTraces" num="100">
 2544       <synopsis>Get All Stack Traces</synopsis>
 2545       <description>
 2546         Get information about the stacks of all live threads
 2547         (including <internallink id="RunAgentThread">agent threads</internallink>).
 2548         If <paramlink id="max_frame_count"/> is less than the depth of a stack,
 2549         the <paramlink id="max_frame_count"/> topmost frames are returned for that thread,
 2550         otherwise the entire stack is returned.
 2551         The topmost frames, those most recently invoked, are at the beginning of the returned buffer.
 2552         <p/>
 2553         All stacks are collected simultaneously, that is, no changes will occur to the
 2554         thread state or stacks between the sampling of one thread and the next.
 2555         The threads need not be suspended.
 2556 
 2557         <example>
 2558 jvmtiStackInfo *stack_info;
 2559 jint thread_count;
 2560 int ti;
 2561 jvmtiError err;
 2562 
 2563 err = (*jvmti)-&gt;GetAllStackTraces(jvmti, MAX_FRAMES, &amp;stack_info, &amp;thread_count);
 2564 if (err != JVMTI_ERROR_NONE) {
 2565    ...
 2566 }
 2567 for (ti = 0; ti &lt; thread_count; ++ti) {
 2568    jvmtiStackInfo *infop = &amp;stack_info[ti];
 2569    jthread thread = infop-&gt;thread;
 2570    jint state = infop-&gt;state;
 2571    jvmtiFrameInfo *frames = infop-&gt;frame_buffer;
 2572    int fi;
 2573 
 2574    myThreadAndStatePrinter(thread, state);
 2575    for (fi = 0; fi &lt; infop-&gt;frame_count; fi++) {
 2576       myFramePrinter(frames[fi].method, frames[fi].location);
 2577    }
 2578 }
 2579 /* this one Deallocate call frees all data allocated by GetAllStackTraces */
 2580 err = (*jvmti)-&gt;Deallocate(jvmti, stack_info);
 2581         </example>
 2582         <todo>
 2583           check example code.
 2584         </todo>
 2585 
 2586       </description>
 2587       <origin>new</origin>
 2588       <capabilities>
 2589       </capabilities>
 2590       <parameters>
 2591         <param id="max_frame_count">
 2592           <jint min="0"/>
 2593           <description>
 2594             The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve per thread.
 2595           </description>
 2596         </param>
 2597         <param id="stack_info_ptr">
 2598           <allocbuf>
 2599             <struct>jvmtiStackInfo</struct>
 2600           </allocbuf>
 2601             <description>
 2602               On return, this buffer is filled
 2603               with stack information for each thread.
 2604               The number of <datalink id="jvmtiStackInfo"/> records is determined
 2605               by <paramlink id="thread_count_ptr"/>.
 2606               <p/>
 2607               Note that this buffer is allocated to include the <datalink id="jvmtiFrameInfo"/>
 2608               buffers pointed to by <datalink id="jvmtiStackInfo.frame_buffer"/>.
 2609               These buffers must not be separately deallocated.
 2610             </description>
 2611         </param>
 2612         <param id="thread_count_ptr">
 2613           <outptr><jint/></outptr>
 2614           <description>
 2615             The number of threads traced.
 2616           </description>
 2617         </param>
 2618       </parameters>
 2619       <errors>
 2620       </errors>
 2621     </function>
 2622 
 2623     <function id="GetThreadListStackTraces" num="101">
 2624       <synopsis>Get Thread List Stack Traces</synopsis>
 2625       <description>
 2626         Get information about the stacks of the supplied threads.
 2627         If <paramlink id="max_frame_count"/> is less than the depth of a stack,
 2628         the <paramlink id="max_frame_count"/> topmost frames are returned for that thread,
 2629         otherwise the entire stack is returned.
 2630         The topmost frames, those most recently invoked, are at the beginning of the returned buffer.
 2631         <p/>
 2632         All stacks are collected simultaneously, that is, no changes will occur to the
 2633         thread state or stacks between the sampling one thread and the next.
 2634         The threads need not be suspended.
 2635         <p/>
 2636         If a thread has not yet started or terminates before the stack information is collected,
 2637         a zero length stack (<datalink id="jvmtiStackInfo.frame_count"/> will be zero)
 2638         will be returned and the thread <datalink id="jvmtiStackInfo.state"/> can be checked.
 2639         <p/>
 2640         See the example for the similar function
 2641         <functionlink id="GetAllStackTraces"/>.
 2642       </description>
 2643       <origin>new</origin>
 2644       <capabilities>
 2645       </capabilities>
 2646       <parameters>
 2647         <param id="thread_count">
 2648           <jint min="0"/>
 2649           <description>
 2650             The number of threads to trace.
 2651           </description>
 2652         </param>
 2653         <param id="thread_list">
 2654           <inbuf incount="thread_count"><jthread/></inbuf>
 2655             <description>
 2656               The list of threads to trace.
 2657             </description>
 2658         </param>
 2659         <param id="max_frame_count">
 2660           <jint min="0"/>
 2661           <description>
 2662             The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve per thread.
 2663           </description>
 2664         </param>
 2665         <param id="stack_info_ptr">
 2666           <allocbuf outcount="thread_count">
 2667             <struct>jvmtiStackInfo</struct>
 2668           </allocbuf>
 2669             <description>
 2670               On return, this buffer is filled
 2671               with stack information for each thread.
 2672               The number of <datalink id="jvmtiStackInfo"/> records is determined
 2673               by <paramlink id="thread_count"/>.
 2674               <p/>
 2675               Note that this buffer is allocated to include the <datalink id="jvmtiFrameInfo"/>
 2676               buffers pointed to by <datalink id="jvmtiStackInfo.frame_buffer"/>.
 2677               These buffers must not be separately deallocated.
 2678             </description>
 2679         </param>
 2680       </parameters>
 2681       <errors>
 2682         <error id="JVMTI_ERROR_INVALID_THREAD">
 2683           An element in <paramlink id="thread_list"/> is not a thread object.
 2684         </error>
 2685       </errors>
 2686     </function>
 2687 
 2688     <elide>
 2689     <function id="AsyncGetStackTrace" num="1000">
 2690       <synopsis>Get Stack Trace--Asynchronous</synopsis>
 2691       <description>
 2692         Get information about the entire stack of a thread (or a sub-section of it).
 2693         This is the asynchronous version of <functionlink id="GetStackTrace"></functionlink>
 2694         and is reentrant and safe to call
 2695         from asynchronous signal handlers.
 2696         The stack trace is returned only for the calling thread.
 2697         <p/>
 2698         The <functionlink id="GetLineNumberTable"></functionlink>
 2699         function can be used to map locations to line numbers. Note that
 2700         this mapping can be done lazily.
 2701       </description>
 2702       <origin>jvmpi</origin>
 2703       <capabilities>
 2704         <required id="can_get_async_stack_trace"></required>
 2705         <capability id="can_show_JVM_spec_async_frames">
 2706           If <code>false</code>,
 2707           <paramlink id="use_java_stack"></paramlink>
 2708           must be <code>false</code>.
 2709         </capability>
 2710       </capabilities>
 2711       <parameters>
 2712         <param id="use_java_stack">
 2713           <jboolean/>
 2714           <description>
 2715             Return the stack showing <vmspec/>
 2716             model of the stack;
 2717             otherwise, show the internal representation of the stack with
 2718             inlined and optimized methods missing.  If the virtual machine
 2719             is using the <i>Java Virtual Machine Specification</i> stack model
 2720             internally, this flag is ignored.
 2721           </description>
 2722         </param>
 2723         <param id="max_count">
 2724           <jint min="0"/>
 2725           <description>
 2726             The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve.
 2727             Retrieve this many unless the stack depth is less than <code>max_count</code>.
 2728           </description>
 2729         </param>
 2730         <param id="frame_buffer">
 2731           <outbuf incount="max_count" outcount="count_ptr">
 2732             <struct>jvmtiFrameInfo</struct>
 2733             <nullok>this information is not returned</nullok>
 2734           </outbuf>
 2735             <description>
 2736               The agent passes in a buffer
 2737               large enough to hold <code>max_count</code> records of
 2738               <datalink id="jvmtiFrameInfo"></datalink>.  This buffer must be
 2739               pre-allocated by the agent.
 2740             </description>
 2741         </param>
 2742         <param id="count_ptr">
 2743           <outptr><jint/></outptr>
 2744           <description>
 2745             On return, points to the number of records filled in..
 2746           </description>
 2747         </param>
 2748       </parameters>
 2749       <errors>
 2750         <error id="JVMTI_ERROR_UNATTACHED_THREAD">
 2751           The thread being used to call this function is not attached
 2752           to the virtual machine.  Calls must be made from attached threads.
 2753         </error>
 2754       </errors>
 2755     </function>
 2756     </elide>
 2757 
 2758     <function id="GetFrameCount" num="16">
 2759       <synopsis>Get Frame Count</synopsis>
 2760       <description>
 2761         Get the number of frames currently in the specified thread's call stack.
 2762         <p/>
 2763         If this function is called for a thread actively executing bytecodes (for example,
 2764         not the current thread and not suspended), the information returned is transient.
 2765       </description>
 2766       <origin>jvmdi</origin>
 2767       <capabilities>
 2768       </capabilities>
 2769       <parameters>
 2770         <param id="thread">
 2771           <jthread null="current"/>
 2772             <description>
 2773               The thread to query.
 2774             </description>
 2775         </param>
 2776         <param id="count_ptr">
 2777           <outptr><jint/></outptr>
 2778           <description>
 2779             On return, points to the number of frames in the call stack.
 2780           </description>
 2781         </param>
 2782       </parameters>
 2783       <errors>
 2784       </errors>
 2785     </function>
 2786 
 2787     <function id="PopFrame" num="80">
 2788       <synopsis>Pop Frame</synopsis>
 2789       <description>
 2790         Pop the current frame of <code>thread</code>'s stack.
 2791         Popping a frame takes you to the previous frame.
 2792         When the thread is resumed, the execution
 2793         state of the thread is reset to the state
 2794         immediately before the called method was invoked.
 2795         That is (using <vmspec/> terminology):
 2796           <ul>
 2797             <li>the current frame is discarded as the previous frame becomes the current one</li>
 2798             <li>the operand stack is restored--the argument values are added back
 2799               and if the invoke was not <code>invokestatic</code>,
 2800               <code>objectref</code> is added back as well</li>
 2801             <li>the Java virtual machine PC is restored to the opcode
 2802               of the invoke instruction</li>
 2803           </ul>
 2804         Note however, that any changes to the arguments, which
 2805         occurred in the called method, remain;
 2806         when execution continues, the first instruction to
 2807         execute will be the invoke.
 2808         <p/>
 2809         Between calling <code>PopFrame</code> and resuming the
 2810         thread the state of the stack is undefined.
 2811         To pop frames beyond the first,
 2812         these three steps must be repeated:
 2813         <ul>
 2814           <li>suspend the thread via an event (step, breakpoint, ...)</li>
 2815           <li>call <code>PopFrame</code></li>
 2816           <li>resume the thread</li>
 2817         </ul>
 2818         <p/>
 2819         A lock acquired by calling the called method
 2820         (if it is a <code>synchronized</code>  method)
 2821         and locks acquired by entering <code>synchronized</code>
 2822         blocks within the called method are released.
 2823         Note: this does not apply to native locks or
 2824         <code>java.util.concurrent.locks</code> locks.
 2825         <p/>
 2826         Finally blocks are not executed.
 2827         <p/>
 2828         Changes to global state are not addressed and thus remain changed.
 2829         <p/>
 2830         The specified thread must be suspended or must be the current thread.
 2831         <p/>
 2832         Both the called method and calling method must be non-native Java programming
 2833         language methods.
 2834         <p/>
 2835         No <jvmti/> events are generated by this function.
 2836       </description>
 2837       <origin>jvmdi</origin>
 2838       <capabilities>
 2839         <required id="can_pop_frame"></required>
 2840       </capabilities>
 2841       <parameters>
 2842         <param id="thread">
 2843           <jthread/>
 2844             <description>
 2845               The thread whose current frame is to be popped.
 2846             </description>
 2847         </param>
 2848       </parameters>
 2849       <errors>
 2850         <error id="JVMTI_ERROR_OPAQUE_FRAME">
 2851           Called or calling method is a native method.
 2852           The implementation is unable to pop this frame.
 2853         </error>
 2854         <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
 2855           Thread was not suspended and was not the current thread.
 2856         </error>
 2857         <error id="JVMTI_ERROR_NO_MORE_FRAMES">
 2858           There are less than two stack frames on the call stack.
 2859         </error>
 2860       </errors>
 2861     </function>
 2862 
 2863     <function id="GetFrameLocation" num="19">
 2864       <synopsis>Get Frame Location</synopsis>
 2865       <description>
 2866         <p/>
 2867         For a Java programming language frame, return the location of the instruction
 2868         currently executing.
 2869       </description>
 2870       <origin>jvmdiClone</origin>
 2871       <capabilities>
 2872       </capabilities>
 2873       <parameters>
 2874         <param id="thread">
 2875           <jthread null="current" frame="frame"/>
 2876           <description>
 2877             The thread of the frame to query.
 2878           </description>
 2879         </param>
 2880         <param id="depth">
 2881           <jframeID thread="thread"/>
 2882           <description>
 2883             The depth of the frame to query.
 2884           </description>
 2885         </param>
 2886         <param id="method_ptr">
 2887           <outptr><jmethodID/></outptr>
 2888             <description>
 2889               On return, points to the method for the current location.
 2890             </description>
 2891         </param>
 2892         <param id="location_ptr">
 2893           <outptr><jlocation/></outptr>
 2894           <description>
 2895             On return, points to the index of the currently
 2896             executing instruction.
 2897             Is set to <code>-1</code> if the frame is executing
 2898             a native method.
 2899           </description>
 2900         </param>
 2901       </parameters>
 2902       <errors>
 2903       </errors>
 2904     </function>
 2905 
 2906     <function id="NotifyFramePop" num="20">
 2907       <synopsis>Notify Frame Pop</synopsis>
 2908       <description>
 2909         When the frame that is currently at <paramlink id="depth"></paramlink>
 2910         is popped from the stack, generate a
 2911         <eventlink id="FramePop"></eventlink> event.  See the
 2912         <eventlink id="FramePop"></eventlink> event for details.
 2913         Only frames corresponding to non-native Java programming language
 2914         methods can receive notification.
 2915         <p/>
 2916         The specified thread must be suspended or must be the current thread.
 2917       </description>
 2918       <origin>jvmdi</origin>
 2919       <capabilities>
 2920         <required id="can_generate_frame_pop_events"></required>
 2921       </capabilities>
 2922       <parameters>
 2923         <param id="thread">
 2924           <jthread null="current" frame="depth"/>
 2925           <description>
 2926             The thread of the frame for which the frame pop event will be generated.
 2927           </description>
 2928         </param>
 2929         <param id="depth">
 2930           <jframeID thread="thread"/>
 2931           <description>
 2932             The depth of the frame for which the frame pop event will be generated.
 2933           </description>
 2934         </param>
 2935       </parameters>
 2936       <errors>
 2937         <error id="JVMTI_ERROR_OPAQUE_FRAME">
 2938           The frame at <code>depth</code> is executing a
 2939           native method.
 2940         </error>
 2941         <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
 2942           Thread was not suspended and was not the current thread.
 2943         </error>
 2944       </errors>
 2945     </function>
 2946 
 2947   </category>
 2948 
 2949   <category id="ForceEarlyReturn" label="Force Early Return">
 2950     <intro>
 2951       These functions allow an agent to force a method
 2952       to return at any point during its execution.
 2953       The method which will return early is referred to as the <i>called method</i>.
 2954       The called method is the current method
 2955       (as defined by
 2956       <vmspec chapter="3.6"/>)
 2957       for the specified thread at
 2958       the time the function is called.
 2959       <p/>
 2960       The specified thread must be suspended or must be the current thread.
 2961       The return occurs when execution of Java programming
 2962       language code is resumed on this thread.
 2963       Between calling one of these functions and resumption
 2964       of thread execution, the state of the stack is undefined.
 2965       <p/>
 2966       No further instructions are executed in the called method.
 2967       Specifically, finally blocks are not executed.
 2968       Note: this can cause inconsistent states in the application.
 2969       <p/>
 2970       A lock acquired by calling the called method
 2971       (if it is a <code>synchronized</code>  method)
 2972       and locks acquired by entering <code>synchronized</code>
 2973       blocks within the called method are released.
 2974       Note: this does not apply to native locks or
 2975       <code>java.util.concurrent.locks</code> locks.
 2976       <p/>
 2977       Events, such as <eventlink id="MethodExit"></eventlink>,
 2978       are generated as they would be in a normal return.
 2979       <p/>
 2980       The called method must be a non-native Java programming
 2981       language method.
 2982       Forcing return on a thread with only one frame on the
 2983       stack causes the thread to exit when resumed.
 2984     </intro>
 2985 
 2986     <function id="ForceEarlyReturnObject" num="81" since="1.1">
 2987       <synopsis>Force Early Return - Object</synopsis>
 2988       <description>
 2989         This function can be used to return from a method whose
 2990         result type is <code>Object</code>
 2991         or a subclass of <code>Object</code>.
 2992       </description>
 2993       <origin>new</origin>
 2994       <capabilities>
 2995         <required id="can_force_early_return"></required>
 2996       </capabilities>
 2997       <parameters>
 2998         <param id="thread">
 2999           <jthread null="current"/>
 3000           <description>
 3001             The thread whose current frame is to return early.
 3002           </description>
 3003         </param>
 3004         <param id="value">
 3005           <jobject/>
 3006           <description>
 3007             The return value for the called frame.
 3008             An object or <code>NULL</code>.
 3009           </description>
 3010         </param>
 3011       </parameters>
 3012       <errors>
 3013         <error id="JVMTI_ERROR_OPAQUE_FRAME">
 3014           Attempted to return early from a frame
 3015           corresponding to a native method.
 3016           Or the implementation is unable to provide
 3017           this functionality on this frame.
 3018         </error>
 3019         <error id="JVMTI_ERROR_TYPE_MISMATCH">
 3020           The result type of the called method is not
 3021           <code>Object</code> or a subclass of <code>Object</code>.
 3022         </error>
 3023         <error id="JVMTI_ERROR_TYPE_MISMATCH">
 3024           The supplied <paramlink id="value"/> is not compatible with the
 3025           result type of the called method.
 3026         </error>
 3027         <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
 3028           Thread was not suspended and was not the current thread.
 3029         </error>
 3030         <error id="JVMTI_ERROR_NO_MORE_FRAMES">
 3031           There are no more frames on the call stack.
 3032         </error>
 3033       </errors>
 3034     </function>
 3035 
 3036     <function id="ForceEarlyReturnInt" num="82" since="1.1">
 3037       <synopsis>Force Early Return - Int</synopsis>
 3038       <description>
 3039         This function can be used to return from a method whose
 3040         result type is <code>int</code>, <code>short</code>,
 3041         <code>char</code>, <code>byte</code>, or
 3042         <code>boolean</code>.
 3043       </description>
 3044       <origin>new</origin>
 3045       <capabilities>
 3046         <required id="can_force_early_return"></required>
 3047       </capabilities>
 3048       <parameters>
 3049         <param id="thread">
 3050           <jthread null="current"/>
 3051           <description>
 3052             The thread whose current frame is to return early.
 3053           </description>
 3054         </param>
 3055         <param id="value">
 3056           <jint/>
 3057           <description>
 3058             The return value for the called frame.
 3059           </description>
 3060         </param>
 3061       </parameters>
 3062       <errors>
 3063         <error id="JVMTI_ERROR_OPAQUE_FRAME">
 3064           Attempted to return early from a frame
 3065           corresponding to a native method.
 3066           Or the implementation is unable to provide
 3067           this functionality on this frame.
 3068         </error>
 3069         <error id="JVMTI_ERROR_TYPE_MISMATCH">
 3070           The result type of the called method is not
 3071           <code>int</code>, <code>short</code>,
 3072           <code>char</code>, <code>byte</code>, or
 3073           <code>boolean</code>.
 3074         </error>
 3075         <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
 3076           Thread was not suspended and was not the current thread.
 3077         </error>
 3078         <error id="JVMTI_ERROR_NO_MORE_FRAMES">
 3079           There are no frames on the call stack.
 3080         </error>
 3081       </errors>
 3082     </function>
 3083 
 3084     <function id="ForceEarlyReturnLong" num="83" since="1.1">
 3085       <synopsis>Force Early Return - Long</synopsis>
 3086       <description>
 3087         This function can be used to return from a method whose
 3088         result type is <code>long</code>.
 3089       </description>
 3090       <origin>new</origin>
 3091       <capabilities>
 3092         <required id="can_force_early_return"></required>
 3093       </capabilities>
 3094       <parameters>
 3095         <param id="thread">
 3096           <jthread null="current"/>
 3097           <description>
 3098             The thread whose current frame is to return early.
 3099           </description>
 3100         </param>
 3101         <param id="value">
 3102           <jlong/>
 3103           <description>
 3104             The return value for the called frame.
 3105           </description>
 3106         </param>
 3107       </parameters>
 3108       <errors>
 3109         <error id="JVMTI_ERROR_OPAQUE_FRAME">
 3110           Attempted to return early from a frame
 3111           corresponding to a native method.
 3112           Or the implementation is unable to provide
 3113           this functionality on this frame.
 3114         </error>
 3115         <error id="JVMTI_ERROR_TYPE_MISMATCH">
 3116           The result type of the called method is not <code>long</code>.
 3117         </error>
 3118         <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
 3119           Thread was not suspended and was not the current thread.
 3120         </error>
 3121         <error id="JVMTI_ERROR_NO_MORE_FRAMES">
 3122           There are no frames on the call stack.
 3123         </error>
 3124       </errors>
 3125     </function>
 3126 
 3127     <function id="ForceEarlyReturnFloat" num="84" since="1.1">
 3128       <synopsis>Force Early Return - Float</synopsis>
 3129       <description>
 3130         This function can be used to return from a method whose
 3131         result type is <code>float</code>.
 3132       </description>
 3133       <origin>new</origin>
 3134       <capabilities>
 3135         <required id="can_force_early_return"></required>
 3136       </capabilities>
 3137       <parameters>
 3138         <param id="thread">
 3139           <jthread null="current"/>
 3140           <description>
 3141             The thread whose current frame is to return early.
 3142           </description>
 3143         </param>
 3144         <param id="value">
 3145           <jfloat/>
 3146           <description>
 3147             The return value for the called frame.
 3148           </description>
 3149         </param>
 3150       </parameters>
 3151       <errors>
 3152         <error id="JVMTI_ERROR_OPAQUE_FRAME">
 3153           Attempted to return early from a frame
 3154           corresponding to a native method.
 3155           Or the implementation is unable to provide
 3156           this functionality on this frame.
 3157         </error>
 3158         <error id="JVMTI_ERROR_TYPE_MISMATCH">
 3159           The result type of the called method is not <code>float</code>.
 3160         </error>
 3161         <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
 3162           Thread was not suspended and was not the current thread.
 3163         </error>
 3164         <error id="JVMTI_ERROR_NO_MORE_FRAMES">
 3165           There are no frames on the call stack.
 3166         </error>
 3167       </errors>
 3168     </function>
 3169 
 3170     <function id="ForceEarlyReturnDouble" num="85" since="1.1">
 3171       <synopsis>Force Early Return - Double</synopsis>
 3172       <description>
 3173         This function can be used to return from a method whose
 3174         result type is <code>double</code>.
 3175       </description>
 3176       <origin>new</origin>
 3177       <capabilities>
 3178         <required id="can_force_early_return"></required>
 3179       </capabilities>
 3180       <parameters>
 3181         <param id="thread">
 3182           <jthread null="current"/>
 3183           <description>
 3184             The thread whose current frame is to return early.
 3185           </description>
 3186         </param>
 3187         <param id="value">
 3188           <jdouble/>
 3189           <description>
 3190             The return value for the called frame.
 3191           </description>
 3192         </param>
 3193       </parameters>
 3194       <errors>
 3195         <error id="JVMTI_ERROR_OPAQUE_FRAME">
 3196           Attempted to return early from a frame corresponding to a native method.
 3197           Or the implementation is unable to provide this functionality on this frame.
 3198         </error>
 3199         <error id="JVMTI_ERROR_TYPE_MISMATCH">
 3200           The result type of the called method is not <code>double</code>.
 3201         </error>
 3202         <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
 3203           Thread was not suspended and was not the current thread.
 3204         </error>
 3205         <error id="JVMTI_ERROR_NO_MORE_FRAMES">
 3206           There are no frames on the call stack.
 3207         </error>
 3208       </errors>
 3209     </function>
 3210 
 3211     <function id="ForceEarlyReturnVoid" num="86" since="1.1">
 3212       <synopsis>Force Early Return - Void</synopsis>
 3213       <description>
 3214         This function can be used to return from a method with no result type.
 3215         That is, the called method must be declared <code>void</code>.
 3216       </description>
 3217       <origin>new</origin>
 3218       <capabilities>
 3219         <required id="can_force_early_return"></required>
 3220       </capabilities>
 3221       <parameters>
 3222         <param id="thread">
 3223           <jthread null="current"/>
 3224           <description>
 3225             The thread whose current frame is to return early.
 3226           </description>
 3227         </param>
 3228       </parameters>
 3229       <errors>
 3230         <error id="JVMTI_ERROR_OPAQUE_FRAME">
 3231           Attempted to return early from a frame
 3232           corresponding to a native method.
 3233           Or the implementation is unable to provide
 3234           this functionality on this frame.
 3235         </error>
 3236         <error id="JVMTI_ERROR_TYPE_MISMATCH">
 3237           The called method has a result type.
 3238         </error>
 3239         <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
 3240           Thread was not suspended and was not the current thread.
 3241         </error>
 3242         <error id="JVMTI_ERROR_NO_MORE_FRAMES">
 3243           There are no frames on the call stack.
 3244         </error>
 3245       </errors>
 3246     </function>
 3247 
 3248   </category>
 3249 
 3250   <category id="Heap" label="Heap">
 3251     <intro>
 3252       These functions are used to analyze the heap.
 3253       Functionality includes the ability to view the objects in the
 3254       heap and to tag these objects.
 3255     </intro>
 3256 
 3257     <intro id="objectTags" label="Object Tags">
 3258       A <i>tag</i> is a value associated with an object.
 3259       Tags are explicitly set by the agent using the
 3260       <functionlink id="SetTag"></functionlink> function or by
 3261       callback functions such as <functionlink id="jvmtiHeapIterationCallback"/>.
 3262       <p/>
 3263       Tags are local to the environment; that is, the tags of one
 3264       environment are not visible in another.
 3265       <p/>
 3266       Tags are <code>jlong</code> values which can be used
 3267       simply to mark an object or to store a pointer to more detailed
 3268       information.  Objects which have not been tagged have a
 3269       tag of zero.
 3270       Setting a tag to zero makes the object untagged.
 3271     </intro>
 3272 
 3273     <intro id="heapCallbacks" label="Heap Callback Functions">
 3274         Heap functions which iterate through the heap and recursively
 3275         follow object references use agent supplied callback functions
 3276         to deliver the information.
 3277         <p/>
 3278         These heap callback functions must adhere to the following restrictions --
 3279         These callbacks must not use JNI functions.
 3280         These callbacks must not use <jvmti/> functions except
 3281         <i>callback safe</i> functions which
 3282         specifically allow such use (see the raw monitor, memory management,
 3283         and environment local storage functions).
 3284         <p/>
 3285         An implementation may invoke a callback on an internal thread or
 3286         the thread which called the iteration function.
 3287         Heap callbacks are single threaded -- no more than one callback will
 3288         be invoked at a time.
 3289         <p/>
 3290         The Heap Filter Flags can be used to prevent reporting
 3291         based on the tag status of an object or its class.
 3292         If no flags are set (the <code>jint</code> is zero), objects
 3293         will not be filtered out.
 3294 
 3295         <constants id="jvmtiHeapFilter" label="Heap Filter Flags" kind="bits">
 3296           <constant id="JVMTI_HEAP_FILTER_TAGGED" num="0x4">
 3297             Filter out tagged objects. Objects which are tagged are not included.
 3298           </constant>
 3299           <constant id="JVMTI_HEAP_FILTER_UNTAGGED" num="0x8">
 3300             Filter out untagged objects. Objects which are not tagged are not included.
 3301           </constant>
 3302           <constant id="JVMTI_HEAP_FILTER_CLASS_TAGGED" num="0x10">
 3303             Filter out objects with tagged classes. Objects whose class is tagged are not included.
 3304           </constant>
 3305           <constant id="JVMTI_HEAP_FILTER_CLASS_UNTAGGED" num="0x20">
 3306             Filter out objects with untagged classes. Objects whose class is not tagged are not included.
 3307           </constant>
 3308         </constants>
 3309 
 3310         <p/>
 3311         The Heap Visit Control Flags are returned by the heap callbacks
 3312         and can be used to abort the iteration.  For the
 3313         <functionlink id="jvmtiHeapReferenceCallback">Heap
 3314         Reference Callback</functionlink>, it can also be used
 3315         to prune the graph of traversed references
 3316         (<code>JVMTI_VISIT_OBJECTS</code> is not set).
 3317 
 3318         <constants id="jvmtiHeapVisitControl"
 3319                    label="Heap Visit Control Flags"
 3320                    kind="bits"
 3321                    since="1.1">
 3322           <constant id="JVMTI_VISIT_OBJECTS" num="0x100">
 3323             If we are visiting an object and if this callback
 3324             was initiated by <functionlink id="FollowReferences"/>,
 3325             traverse the references of this object.
 3326             Otherwise ignored.
 3327           </constant>
 3328           <constant id="JVMTI_VISIT_ABORT" num="0x8000">
 3329             Abort the iteration.  Ignore all other bits.
 3330           </constant>
 3331         </constants>
 3332 
 3333         <p/>
 3334         The Heap Reference Enumeration is provided by the
 3335         <functionlink id="jvmtiHeapReferenceCallback">Heap
 3336         Reference Callback</functionlink> and
 3337         <functionlink id="jvmtiPrimitiveFieldCallback">Primitive Field
 3338         Callback</functionlink> to
 3339         describe the kind of reference
 3340         being reported.
 3341 
 3342         <constants id="jvmtiHeapReferenceKind"
 3343                    label="Heap Reference Enumeration"
 3344                    kind="enum"
 3345                    since="1.1">
 3346           <constant id="JVMTI_HEAP_REFERENCE_CLASS" num="1">
 3347             Reference from an object to its class.
 3348           </constant>
 3349           <constant id="JVMTI_HEAP_REFERENCE_FIELD" num="2">
 3350             Reference from an object to the value of one of its instance fields.
 3351           </constant>
 3352           <constant id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT" num="3">
 3353             Reference from an array to one of its elements.
 3354           </constant>
 3355           <constant id="JVMTI_HEAP_REFERENCE_CLASS_LOADER" num="4">
 3356             Reference from a class to its class loader.
 3357           </constant>
 3358           <constant id="JVMTI_HEAP_REFERENCE_SIGNERS" num="5">
 3359             Reference from a class to its signers array.
 3360           </constant>
 3361           <constant id="JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN" num="6">
 3362             Reference from a class to its protection domain.
 3363           </constant>
 3364           <constant id="JVMTI_HEAP_REFERENCE_INTERFACE" num="7">
 3365             Reference from a class to one of its interfaces.
 3366             Note: interfaces are defined via a constant pool reference,
 3367             so the referenced interfaces may also be reported with a
 3368             <code>JVMTI_HEAP_REFERENCE_CONSTANT_POOL</code> reference kind.
 3369           </constant>
 3370           <constant id="JVMTI_HEAP_REFERENCE_STATIC_FIELD" num="8">
 3371             Reference from a class to the value of one of its static fields.
 3372           </constant>
 3373           <constant id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL" num="9">
 3374             Reference from a class to a resolved entry in the constant pool.
 3375           </constant>
 3376           <constant id="JVMTI_HEAP_REFERENCE_SUPERCLASS" num="10">
 3377             Reference from a class to its superclass.
 3378             A callback is not sent if the superclass is <code>java.lang.Object</code>.
 3379             Note: loaded classes define superclasses via a constant pool
 3380             reference, so the referenced superclass may also be reported with
 3381             a <code>JVMTI_HEAP_REFERENCE_CONSTANT_POOL</code> reference kind.
 3382           </constant>
 3383           <constant id="JVMTI_HEAP_REFERENCE_JNI_GLOBAL" num="21">
 3384             Heap root reference: JNI global reference.
 3385           </constant>
 3386           <constant id="JVMTI_HEAP_REFERENCE_SYSTEM_CLASS" num="22">
 3387             Heap root reference: System class.
 3388           </constant>
 3389           <constant id="JVMTI_HEAP_REFERENCE_MONITOR" num="23">
 3390             Heap root reference: monitor.
 3391           </constant>
 3392           <constant id="JVMTI_HEAP_REFERENCE_STACK_LOCAL" num="24">
 3393             Heap root reference: local variable on the stack.
 3394           </constant>
 3395           <constant id="JVMTI_HEAP_REFERENCE_JNI_LOCAL" num="25">
 3396             Heap root reference: JNI local reference.
 3397           </constant>
 3398           <constant id="JVMTI_HEAP_REFERENCE_THREAD" num="26">
 3399             Heap root reference: Thread.
 3400           </constant>
 3401           <constant id="JVMTI_HEAP_REFERENCE_OTHER" num="27">
 3402             Heap root reference: other heap root reference.
 3403           </constant>
 3404         </constants>
 3405 
 3406         <p/>
 3407         Definitions for the single character type descriptors of
 3408         primitive types.
 3409 
 3410         <constants id="jvmtiPrimitiveType"
 3411                    label="Primitive Type Enumeration"
 3412                    kind="enum"
 3413                    since="1.1">
 3414           <constant id="JVMTI_PRIMITIVE_TYPE_BOOLEAN" num="90">
 3415             'Z' - Java programming language <code>boolean</code> - JNI <code>jboolean</code>
 3416           </constant>
 3417           <constant id="JVMTI_PRIMITIVE_TYPE_BYTE" num="66">
 3418             'B' - Java programming language <code>byte</code> - JNI <code>jbyte</code>
 3419           </constant>
 3420           <constant id="JVMTI_PRIMITIVE_TYPE_CHAR" num="67">
 3421             'C' - Java programming language <code>char</code> - JNI <code>jchar</code>
 3422           </constant>
 3423           <constant id="JVMTI_PRIMITIVE_TYPE_SHORT" num="83">
 3424             'S' - Java programming language <code>short</code> - JNI <code>jshort</code>
 3425           </constant>
 3426           <constant id="JVMTI_PRIMITIVE_TYPE_INT" num="73">
 3427             'I' - Java programming language <code>int</code> - JNI <code>jint</code>
 3428           </constant>
 3429           <constant id="JVMTI_PRIMITIVE_TYPE_LONG" num="74">
 3430             'J' - Java programming language <code>long</code> - JNI <code>jlong</code>
 3431           </constant>
 3432           <constant id="JVMTI_PRIMITIVE_TYPE_FLOAT" num="70">
 3433             'F' - Java programming language <code>float</code> - JNI <code>jfloat</code>
 3434           </constant>
 3435           <constant id="JVMTI_PRIMITIVE_TYPE_DOUBLE" num="68">
 3436             'D' - Java programming language <code>double</code> - JNI <code>jdouble</code>
 3437           </constant>
 3438         </constants>
 3439     </intro>
 3440 
 3441       <typedef id="jvmtiHeapReferenceInfoField"
 3442                label="Reference information structure for Field references"
 3443                since="1.1">
 3444         <description>
 3445           Reference information returned for
 3446           <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/> and
 3447           <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/> references.
 3448         </description>
 3449         <field id="index">
 3450           <jint/>
 3451           <description>
 3452             For <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/>, the
 3453             referrer object is not a class or an interface.
 3454             In this case, <code>index</code> is the index of the field
 3455             in the class of the referrer object.
 3456             This class is referred to below as <i>C</i>.
 3457             <p/>
 3458             For <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/>,
 3459             the referrer object is a class (referred to below as <i>C</i>)
 3460             or an interface (referred to below as <i>I</i>).
 3461             In this case, <code>index</code> is the index of the field in
 3462             that class or interface.
 3463             <p/>
 3464             If the referrer object is not an interface, then the field
 3465             indices are determined as follows:
 3466             <ul>
 3467               <li>make a list of all the fields in <i>C</i> and its
 3468                   superclasses, starting with all the fields in
 3469                   <code>java.lang.Object</code> and ending with all the
 3470                   fields in <i>C</i>.</li>
 3471               <li>Within this list, put
 3472                   the fields for a given class in the order returned by
 3473                   <functionlink id="GetClassFields"/>.</li>
 3474               <li>Assign the fields in this list indices
 3475                   <i>n</i>, <i>n</i>+1, ..., in order, where <i>n</i>
 3476                   is the count of the fields in all the interfaces
 3477                   implemented by <i>C</i>.
 3478                   Note that <i>C</i> implements all interfaces
 3479                   directly implemented by its superclasses; as well
 3480                   as all superinterfaces of these interfaces.</li>
 3481             </ul>
 3482             If the referrer object is an interface, then the field
 3483             indices are determined as follows:
 3484             <ul>
 3485               <li>make a list of the fields directly declared in
 3486                   <i>I</i>.</li>
 3487               <li>Within this list, put
 3488                   the fields in the order returned by
 3489                   <functionlink id="GetClassFields"/>.</li>
 3490               <li>Assign the fields in this list indices
 3491                   <i>n</i>, <i>n</i>+1, ..., in order, where <i>n</i>
 3492                   is the count of the fields in all the superinterfaces
 3493                   of <i>I</i>.</li>
 3494             </ul>
 3495             All fields are included in this computation, regardless of
 3496             field modifier (static, public, private, etc).
 3497             <p/>
 3498             For example, given the following classes and interfaces:
 3499             <example>
 3500 interface I0 {
 3501     int p = 0;
 3502 }
 3503 
 3504 interface I1 extends I0 {
 3505     int x = 1;
 3506 }
 3507 
 3508 interface I2 extends I0 {
 3509     int y = 2;
 3510 }
 3511 
 3512 class C1 implements I1 {
 3513     public static int a = 3;
 3514     private int b = 4;
 3515 }
 3516 
 3517 class C2 extends C1 implements I2 {
 3518     static int q = 5;
 3519     final int r = 6;
 3520 }
 3521             </example>
 3522             Assume that <functionlink id="GetClassFields"/> called on
 3523             <code>C1</code> returns the fields of <code>C1</code> in the
 3524             order: a, b; and that the fields of <code>C2</code> are
 3525             returned in the order: q, r.
 3526             An instance of class <code>C1</code> will have the
 3527             following field indices:
 3528             <blockquote><table>
 3529               <tr class="bgLight">
 3530                 <th class="centered" scope="col">Field</th>
 3531                 <th class="centered" scope="col">Index</th>
 3532                 <th scope="col">Description</th>
 3533               </tr>
 3534               <tr>
 3535                 <th class="centered" scope="row">
 3536                   a
 3537                 </th>
 3538                 <td class="centered">
 3539                   2
 3540                 </td>
 3541                 <td>
 3542                   The count of the fields in the interfaces
 3543                   implemented by <code>C1</code> is two (<i>n</i>=2):
 3544                   <code>p</code> of <code>I0</code>
 3545                   and <code>x</code> of <code>I1</code>.
 3546                 </td>
 3547               </tr>
 3548               <tr>
 3549                 <th class="centered" scope="row">
 3550                   b
 3551                 </th>
 3552                 <td class="centered">
 3553                   3
 3554                 </td>
 3555                 <td>
 3556                   the subsequent index.
 3557                 </td>
 3558               </tr>
 3559             </table></blockquote>
 3560             The class <code>C1</code> will have the same field indices.
 3561             <p/>
 3562             An instance of class <code>C2</code> will have the
 3563             following field indices:
 3564             <blockquote><table>
 3565               <tr class="bgLight">
 3566                 <th class="centered" scope="col">Field</th>
 3567                 <th class="centered" scope="col">Index</th>
 3568                 <th scope="col">Description</th>
 3569               </tr>
 3570               <tr>
 3571                 <th class="centered" scope="row">
 3572                   a
 3573                 </th>
 3574                 <td class="centered">
 3575                   3
 3576                 </td>
 3577                 <td>
 3578                   The count of the fields in the interfaces
 3579                   implemented by <code>C2</code> is three (<i>n</i>=3):
 3580                   <code>p</code> of <code>I0</code>,
 3581                   <code>x</code> of <code>I1</code> and <code>y</code> of <code>I2</code>
 3582                   (an interface of <code>C2</code>).  Note that the field <code>p</code>
 3583                   of <code>I0</code> is only included once.
 3584                 </td>
 3585               </tr>
 3586               <tr>
 3587                 <th class="centered" scope="row">
 3588                   b
 3589                 </th>
 3590                 <td class="centered">
 3591                   4
 3592                 </td>
 3593                 <td>
 3594                   the subsequent index to "a".
 3595                 </td>
 3596               </tr>
 3597               <tr>
 3598                 <th class="centered" scope="row">
 3599                   q
 3600                 </th>
 3601                 <td class="centered">
 3602                   5
 3603                 </td>
 3604                 <td>
 3605                   the subsequent index to "b".
 3606                 </td>
 3607               </tr>
 3608               <tr>
 3609                 <th class="centered" scope="row">
 3610                   r
 3611                 </th>
 3612                 <td class="centered">
 3613                   6
 3614                 </td>
 3615                 <td>
 3616                   the subsequent index to "q".
 3617                 </td>
 3618               </tr>
 3619             </table></blockquote>
 3620             The class <code>C2</code> will have the same field indices.
 3621             Note that a field may have a different index depending on the
 3622             object that is viewing it -- for example field "a" above.
 3623             Note also: not all field indices may be visible from the
 3624             callbacks, but all indices are shown for illustrative purposes.
 3625             <p/>
 3626             The interface <code>I1</code> will have the
 3627             following field indices:
 3628             <blockquote><table>
 3629               <tr class="bgLight">
 3630                 <th class="centered" scope="col">Field</th>
 3631                 <th class="centered" scope="col">Index</th>
 3632                 <th scope="col">Description</th>
 3633               </tr>
 3634               <tr>
 3635                 <th class="centered" scope="row">
 3636                   x
 3637                 </th>
 3638                 <td class="centered">
 3639                   1
 3640                 </td>
 3641                 <td>
 3642                   The count of the fields in the superinterfaces
 3643                   of <code>I1</code> is one (<i>n</i>=1):
 3644                   <code>p</code> of <code>I0</code>.
 3645                 </td>
 3646               </tr>
 3647             </table></blockquote>
 3648           </description>
 3649         </field>
 3650       </typedef>
 3651 
 3652       <typedef id="jvmtiHeapReferenceInfoArray"
 3653                label="Reference information structure for Array references"
 3654                since="1.1">
 3655         <description>
 3656           Reference information returned for
 3657          <datalink id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT"/> references.
 3658         </description>
 3659         <field id="index">
 3660           <jint/>
 3661           <description>
 3662             The array index.
 3663           </description>
 3664         </field>
 3665       </typedef>
 3666 
 3667       <typedef id="jvmtiHeapReferenceInfoConstantPool"
 3668                label="Reference information structure for Constant Pool references"
 3669                since="1.1">
 3670         <description>
 3671           Reference information returned for
 3672           <datalink id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL"/> references.
 3673         </description>
 3674         <field id="index">
 3675           <jint/>
 3676           <description>
 3677             The index into the constant pool of the class. See the description in
 3678       <vmspec chapter="4.4"/>.
 3679           </description>
 3680         </field>
 3681       </typedef>
 3682 
 3683       <typedef id="jvmtiHeapReferenceInfoStackLocal"
 3684                label="Reference information structure for Local Variable references"
 3685                since="1.1">
 3686         <description>
 3687           Reference information returned for
 3688           <datalink id="JVMTI_HEAP_REFERENCE_STACK_LOCAL"/> references.
 3689         </description>
 3690         <field id="thread_tag">
 3691           <jlong/>
 3692           <description>
 3693             The tag of the thread corresponding to this stack, zero if not tagged.
 3694           </description>
 3695         </field>
 3696         <field id="thread_id">
 3697           <jlong/>
 3698           <description>
 3699             The unique thread ID of the thread corresponding to this stack.
 3700           </description>
 3701         </field>
 3702         <field id="depth">
 3703           <jint/>
 3704           <description>
 3705             The depth of the frame.
 3706           </description>
 3707         </field>
 3708         <field id="method">
 3709           <jmethodID/>
 3710           <description>
 3711             The method executing in this frame.
 3712           </description>
 3713         </field>
 3714         <field id="location">
 3715           <jlocation/>
 3716           <description>
 3717             The currently executing location in this frame.
 3718           </description>
 3719         </field>
 3720         <field id="slot">
 3721           <jint/>
 3722           <description>
 3723             The slot number of the local variable.
 3724           </description>
 3725         </field>
 3726       </typedef>
 3727 
 3728       <typedef id="jvmtiHeapReferenceInfoJniLocal"
 3729                label="Reference information structure for JNI local references"
 3730                since="1.1">
 3731         <description>
 3732           Reference information returned for
 3733           <datalink id="JVMTI_HEAP_REFERENCE_JNI_LOCAL"/> references.
 3734         </description>
 3735         <field id="thread_tag">
 3736           <jlong/>
 3737           <description>
 3738             The tag of the thread corresponding to this stack, zero if not tagged.
 3739           </description>
 3740         </field>
 3741         <field id="thread_id">
 3742           <jlong/>
 3743           <description>
 3744             The unique thread ID of the thread corresponding to this stack.
 3745           </description>
 3746         </field>
 3747         <field id="depth">
 3748           <jint/>
 3749           <description>
 3750             The depth of the frame.
 3751           </description>
 3752         </field>
 3753         <field id="method">
 3754           <jmethodID/>
 3755           <description>
 3756             The method executing in this frame.
 3757           </description>
 3758         </field>
 3759       </typedef>
 3760 
 3761       <typedef id="jvmtiHeapReferenceInfoReserved"
 3762                label="Reference information structure for Other references"
 3763                since="1.1">
 3764         <description>
 3765           Reference information returned for other references.
 3766         </description>
 3767         <field id="reserved1">
 3768           <jlong/>
 3769           <description>
 3770             reserved for future use.
 3771           </description>
 3772         </field>
 3773         <field id="reserved2">
 3774           <jlong/>
 3775           <description>
 3776             reserved for future use.
 3777           </description>
 3778         </field>
 3779         <field id="reserved3">
 3780           <jlong/>
 3781           <description>
 3782             reserved for future use.
 3783           </description>
 3784         </field>
 3785         <field id="reserved4">
 3786           <jlong/>
 3787           <description>
 3788             reserved for future use.
 3789           </description>
 3790         </field>
 3791         <field id="reserved5">
 3792           <jlong/>
 3793           <description>
 3794             reserved for future use.
 3795           </description>
 3796         </field>
 3797         <field id="reserved6">
 3798           <jlong/>
 3799           <description>
 3800             reserved for future use.
 3801           </description>
 3802         </field>
 3803         <field id="reserved7">
 3804           <jlong/>
 3805           <description>
 3806             reserved for future use.
 3807           </description>
 3808         </field>
 3809         <field id="reserved8">
 3810           <jlong/>
 3811           <description>
 3812             reserved for future use.
 3813           </description>
 3814         </field>
 3815       </typedef>
 3816 
 3817       <uniontypedef id="jvmtiHeapReferenceInfo"
 3818                label="Reference information structure"
 3819                since="1.1">
 3820         <description>
 3821           The information returned about referrers.
 3822           Represented as a union of the various kinds of reference information.
 3823         </description>
 3824         <field id="field">
 3825           <struct>jvmtiHeapReferenceInfoField</struct>
 3826           <description>
 3827             The referrer information for
 3828             <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/>
 3829             and <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/> references.
 3830           </description>
 3831         </field>
 3832         <field id="array">
 3833           <struct>jvmtiHeapReferenceInfoArray</struct>
 3834           <description>
 3835             The referrer information for
 3836             For <datalink id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT"/> references.
 3837           </description>
 3838         </field>
 3839         <field id="constant_pool">
 3840           <struct>jvmtiHeapReferenceInfoConstantPool</struct>
 3841           <description>
 3842             The referrer information for
 3843             For <datalink id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL"/> references.
 3844           </description>
 3845         </field>
 3846         <field id="stack_local">
 3847           <struct>jvmtiHeapReferenceInfoStackLocal</struct>
 3848           <description>
 3849             The referrer information for
 3850             For <datalink id="JVMTI_HEAP_REFERENCE_STACK_LOCAL"/> references.
 3851           </description>
 3852         </field>
 3853         <field id="jni_local">
 3854           <struct>jvmtiHeapReferenceInfoJniLocal</struct>
 3855           <description>
 3856             The referrer information for
 3857             For <datalink id="JVMTI_HEAP_REFERENCE_JNI_LOCAL"/> references.
 3858           </description>
 3859         </field>
 3860         <field id="other">
 3861           <struct>jvmtiHeapReferenceInfoReserved</struct>
 3862           <description>
 3863             reserved for future use.
 3864           </description>
 3865         </field>
 3866       </uniontypedef>
 3867 
 3868       <typedef id="jvmtiHeapCallbacks"
 3869                label="Heap callback function structure"
 3870                since="1.1">
 3871         <field id="heap_iteration_callback">
 3872           <ptrtype>
 3873             <struct>jvmtiHeapIterationCallback</struct>
 3874           </ptrtype>
 3875           <description>
 3876             The callback to be called to describe an
 3877             object in the heap. Used by the
 3878             <functionlink id="IterateThroughHeap"/> function, ignored by the
 3879             <functionlink id="FollowReferences"/> function.
 3880           </description>
 3881         </field>
 3882         <field id="heap_reference_callback">
 3883           <ptrtype>
 3884             <struct>jvmtiHeapReferenceCallback</struct>
 3885           </ptrtype>
 3886           <description>
 3887             The callback to be called to describe an
 3888             object reference.  Used by the
 3889             <functionlink id="FollowReferences"/> function, ignored by the
 3890             <functionlink id="IterateThroughHeap"/> function.
 3891           </description>
 3892         </field>
 3893         <field id="primitive_field_callback">
 3894           <ptrtype>
 3895             <struct>jvmtiPrimitiveFieldCallback</struct>
 3896           </ptrtype>
 3897           <description>
 3898             The callback to be called to describe a
 3899             primitive field.
 3900           </description>
 3901         </field>
 3902         <field id="array_primitive_value_callback">
 3903           <ptrtype>
 3904             <struct>jvmtiArrayPrimitiveValueCallback</struct>
 3905           </ptrtype>
 3906           <description>
 3907             The callback to be called to describe an
 3908             array of primitive values.
 3909           </description>
 3910         </field>
 3911         <field id="string_primitive_value_callback">
 3912           <ptrtype>
 3913             <struct>jvmtiStringPrimitiveValueCallback</struct>
 3914           </ptrtype>
 3915           <description>
 3916             The callback to be called to describe a String value.
 3917           </description>
 3918         </field>
 3919         <field id="reserved5">
 3920           <ptrtype>
 3921             <struct>jvmtiReservedCallback</struct>
 3922           </ptrtype>
 3923           <description>
 3924             Reserved for future use..
 3925           </description>
 3926         </field>
 3927         <field id="reserved6">
 3928           <ptrtype>
 3929             <struct>jvmtiReservedCallback</struct>
 3930           </ptrtype>
 3931           <description>
 3932             Reserved for future use..
 3933           </description>
 3934         </field>
 3935         <field id="reserved7">
 3936           <ptrtype>
 3937             <struct>jvmtiReservedCallback</struct>
 3938           </ptrtype>
 3939           <description>
 3940             Reserved for future use..
 3941           </description>
 3942         </field>
 3943         <field id="reserved8">
 3944           <ptrtype>
 3945             <struct>jvmtiReservedCallback</struct>
 3946           </ptrtype>
 3947           <description>
 3948             Reserved for future use..
 3949           </description>
 3950         </field>
 3951         <field id="reserved9">
 3952           <ptrtype>
 3953             <struct>jvmtiReservedCallback</struct>
 3954           </ptrtype>
 3955           <description>
 3956             Reserved for future use..
 3957           </description>
 3958         </field>
 3959         <field id="reserved10">
 3960           <ptrtype>
 3961             <struct>jvmtiReservedCallback</struct>
 3962           </ptrtype>
 3963           <description>
 3964             Reserved for future use..
 3965           </description>
 3966         </field>
 3967         <field id="reserved11">
 3968           <ptrtype>
 3969             <struct>jvmtiReservedCallback</struct>
 3970           </ptrtype>
 3971           <description>
 3972             Reserved for future use..
 3973           </description>
 3974         </field>
 3975         <field id="reserved12">
 3976           <ptrtype>
 3977             <struct>jvmtiReservedCallback</struct>
 3978           </ptrtype>
 3979           <description>
 3980             Reserved for future use..
 3981           </description>
 3982         </field>
 3983         <field id="reserved13">
 3984           <ptrtype>
 3985             <struct>jvmtiReservedCallback</struct>
 3986           </ptrtype>
 3987           <description>
 3988             Reserved for future use..
 3989           </description>
 3990         </field>
 3991         <field id="reserved14">
 3992           <ptrtype>
 3993             <struct>jvmtiReservedCallback</struct>
 3994           </ptrtype>
 3995           <description>
 3996             Reserved for future use..
 3997           </description>
 3998         </field>
 3999         <field id="reserved15">
 4000           <ptrtype>
 4001             <struct>jvmtiReservedCallback</struct>
 4002           </ptrtype>
 4003           <description>
 4004             Reserved for future use..
 4005           </description>
 4006         </field>
 4007       </typedef>
 4008 
 4009 
 4010     <intro>
 4011       <rationale>
 4012         The heap dumping functionality (below) uses a callback
 4013         for each object.  While it would seem that a buffered approach
 4014         would provide better throughput, tests do
 4015         not show this to be the case--possibly due to locality of
 4016         memory reference or array access overhead.
 4017       </rationale>
 4018 
 4019       <issue>
 4020         Still under investigation as to if java.lang.ref references
 4021         are reported as a different type of reference.
 4022       </issue>
 4023 
 4024       <issue>
 4025         Should or can an indication of the cost or relative cost of
 4026         these operations be included?
 4027       </issue>
 4028 
 4029     </intro>
 4030 
 4031     <callback id="jvmtiHeapIterationCallback" since="1.1">
 4032       <jint/>
 4033       <synopsis>Heap Iteration Callback</synopsis>
 4034       <description>
 4035         Agent supplied callback function.
 4036         Describes (but does not pass in) an object in the heap.
 4037         <p/>
 4038         This function should return a bit vector of the desired
 4039         <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
 4040         This will determine if the entire iteration should be aborted
 4041         (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
 4042         <p/>
 4043         See the <internallink id="heapCallbacks">heap callback
 4044         function restrictions</internallink>.
 4045       </description>
 4046       <parameters>
 4047         <param id="class_tag">
 4048           <jlong/>
 4049           <description>
 4050             The tag of the class of object (zero if the class is not tagged).
 4051             If the object represents a runtime class,
 4052             the <code>class_tag</code> is the tag
 4053             associated with <code>java.lang.Class</code>
 4054             (zero if <code>java.lang.Class</code> is not tagged).
 4055           </description>
 4056         </param>
 4057         <param id="size">
 4058           <jlong/>
 4059           <description>
 4060             Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
 4061           </description>
 4062         </param>
 4063         <param id="tag_ptr">
 4064           <outptr><jlong/></outptr>
 4065           <description>
 4066             The object tag value, or zero if the object is not tagged.
 4067             To set the tag value to be associated with the object
 4068             the agent sets the <code>jlong</code> pointed to by the parameter.
 4069           </description>
 4070         </param>
 4071         <param id="length">
 4072           <jint/>
 4073           <description>
 4074             If this object is an array, the length of the array. Otherwise negative one (-1).
 4075           </description>
 4076         </param>
 4077         <param id="user_data">
 4078           <outptr><void/></outptr>
 4079           <description>
 4080             The user supplied data that was passed into the iteration function.
 4081           </description>
 4082         </param>
 4083       </parameters>
 4084     </callback>
 4085 
 4086     <callback id="jvmtiHeapReferenceCallback" since="1.1">
 4087       <jint/>
 4088       <synopsis>Heap Reference Callback</synopsis>
 4089       <description>
 4090         Agent supplied callback function.
 4091         Describes a reference from an object or the VM (the referrer) to another object
 4092         (the referree) or a heap root to a referree.
 4093         <p/>
 4094         This function should return a bit vector of the desired
 4095         <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
 4096         This will determine if the objects referenced by the referree
 4097         should be visited or if the entire iteration should be aborted.
 4098         <p/>
 4099         See the <internallink id="heapCallbacks">heap callback
 4100         function restrictions</internallink>.
 4101       </description>
 4102       <parameters>
 4103         <param id="reference_kind">
 4104           <enum>jvmtiHeapReferenceKind</enum>
 4105           <description>
 4106             The kind of reference.
 4107           </description>
 4108         </param>
 4109         <param id="reference_info">
 4110           <inptr>
 4111             <struct>jvmtiHeapReferenceInfo</struct>
 4112           </inptr>
 4113           <description>
 4114             Details about the reference.
 4115             Set when the <datalink id="jvmtiHeapReferenceCallback.reference_kind">reference_kind</datalink> is
 4116             <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/>,
 4117             <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/>,
 4118             <datalink id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT"/>,
 4119             <datalink id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL"/>,
 4120             <datalink id="JVMTI_HEAP_REFERENCE_STACK_LOCAL"/>,
 4121             or <datalink id="JVMTI_HEAP_REFERENCE_JNI_LOCAL"/>.
 4122             Otherwise <code>NULL</code>.
 4123           </description>
 4124         </param>
 4125         <param id="class_tag">
 4126           <jlong/>
 4127           <description>
 4128             The tag of the class of referree object (zero if the class is not tagged).
 4129             If the referree object represents a runtime class,
 4130             the <code>class_tag</code> is the tag
 4131             associated with <code>java.lang.Class</code>
 4132             (zero if <code>java.lang.Class</code> is not tagged).
 4133           </description>
 4134         </param>
 4135         <param id="referrer_class_tag">
 4136           <jlong/>
 4137           <description>
 4138             The tag of the class of the referrer object (zero if the class is not tagged
 4139             or the referree is a heap root). If the referrer object represents a runtime
 4140             class, the <code>referrer_class_tag</code> is the tag associated with
 4141             the <code>java.lang.Class</code>
 4142             (zero if <code>java.lang.Class</code> is not tagged).
 4143           </description>
 4144         </param>
 4145         <param id="size">
 4146           <jlong/>
 4147           <description>
 4148             Size of the referree object (in bytes).
 4149             See <functionlink id="GetObjectSize"/>.
 4150           </description>
 4151         </param>
 4152         <param id="tag_ptr">
 4153           <outptr><jlong/></outptr>
 4154           <description>
 4155             Points to the referree object tag value, or zero if the object is not
 4156             tagged.
 4157             To set the tag value to be associated with the object
 4158             the agent sets the <code>jlong</code> pointed to by the parameter.
 4159           </description>
 4160         </param>
 4161         <param id="referrer_tag_ptr">
 4162           <outptr><jlong/></outptr>
 4163           <description>
 4164             Points to the tag of the referrer object, or
 4165             points to the zero if the referrer
 4166             object is not tagged.
 4167             <code>NULL</code> if the referrer in not an object (that is,
 4168             this callback is reporting a heap root).
 4169             To set the tag value to be associated with the referrer object
 4170             the agent sets the <code>jlong</code> pointed to by the parameter.
 4171             If this callback is reporting a reference from an object to itself,
 4172             <code>referrer_tag_ptr == tag_ptr</code>.
 4173           </description>
 4174         </param>
 4175         <param id="length">
 4176           <jint/>
 4177           <description>
 4178             If this object is an array, the length of the array. Otherwise negative one (-1).
 4179           </description>
 4180         </param>
 4181         <param id="user_data">
 4182           <outptr><void/></outptr>
 4183           <description>
 4184             The user supplied data that was passed into the iteration function.
 4185           </description>
 4186         </param>
 4187       </parameters>
 4188     </callback>
 4189 
 4190     <callback id="jvmtiPrimitiveFieldCallback" since="1.1">
 4191       <jint/>
 4192       <synopsis>Primitive Field Callback</synopsis>
 4193       <description>
 4194         Agent supplied callback function which
 4195         describes a primitive field of an object (<i>the object</i>).
 4196         A primitive field is a field whose type is a primitive type.
 4197         This callback will describe a static field if the object is a class,
 4198         and otherwise will describe an instance field.
 4199         <p/>
 4200         This function should return a bit vector of the desired
 4201         <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
 4202         This will determine if the entire iteration should be aborted
 4203         (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
 4204         <p/>
 4205         See the <internallink id="heapCallbacks">heap callback
 4206         function restrictions</internallink>.
 4207       </description>
 4208       <parameters>
 4209         <param id="kind">
 4210           <enum>jvmtiHeapReferenceKind</enum>
 4211           <description>
 4212             The kind of field -- instance or static (<datalink id="JVMTI_HEAP_REFERENCE_FIELD"/> or
 4213             <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/>).
 4214           </description>
 4215         </param>
 4216         <param id="info">
 4217           <inptr>
 4218             <struct>jvmtiHeapReferenceInfo</struct>
 4219           </inptr>
 4220           <description>
 4221             Which field (the field index).
 4222           </description>
 4223         </param>
 4224         <param id="object_class_tag">
 4225           <jlong/>
 4226           <description>
 4227             The tag of the class of the object (zero if the class is not tagged).
 4228             If the object represents a runtime class, the
 4229             <code>object_class_tag</code> is the tag
 4230             associated with <code>java.lang.Class</code>
 4231             (zero if <code>java.lang.Class</code> is not tagged).
 4232           </description>
 4233         </param>
 4234         <param id="object_tag_ptr">
 4235           <outptr><jlong/></outptr>
 4236           <description>
 4237             Points to the tag of the object, or zero if the object is not
 4238             tagged.
 4239             To set the tag value to be associated with the object
 4240             the agent sets the <code>jlong</code> pointed to by the parameter.
 4241           </description>
 4242         </param>
 4243         <param id="value">
 4244           <jvalue/>
 4245           <description>
 4246             The value of the field.
 4247           </description>
 4248         </param>
 4249         <param id="value_type">
 4250           <enum>jvmtiPrimitiveType</enum>
 4251           <description>
 4252             The type of the field.
 4253           </description>
 4254         </param>
 4255         <param id="user_data">
 4256           <outptr><void/></outptr>
 4257           <description>
 4258             The user supplied data that was passed into the iteration function.
 4259           </description>
 4260         </param>
 4261       </parameters>
 4262     </callback>
 4263 
 4264     <callback id="jvmtiArrayPrimitiveValueCallback" since="1.1">
 4265       <jint/>
 4266       <synopsis>Array Primitive Value Callback</synopsis>
 4267       <description>
 4268         Agent supplied callback function.
 4269         Describes the values in an array of a primitive type.
 4270         <p/>
 4271         This function should return a bit vector of the desired
 4272         <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
 4273         This will determine if the entire iteration should be aborted
 4274         (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
 4275         <p/>
 4276         See the <internallink id="heapCallbacks">heap callback
 4277         function restrictions</internallink>.
 4278       </description>
 4279       <parameters>
 4280         <param id="class_tag">
 4281           <jlong/>
 4282           <description>
 4283             The tag of the class of the array object (zero if the class is not tagged).
 4284           </description>
 4285         </param>
 4286         <param id="size">
 4287           <jlong/>
 4288           <description>
 4289             Size of the array (in bytes).
 4290             See <functionlink id="GetObjectSize"/>.
 4291           </description>
 4292         </param>
 4293         <param id="tag_ptr">
 4294           <outptr><jlong/></outptr>
 4295           <description>
 4296             Points to the tag of the array object, or zero if the object is not
 4297             tagged.
 4298             To set the tag value to be associated with the object
 4299             the agent sets the <code>jlong</code> pointed to by the parameter.
 4300           </description>
 4301         </param>
 4302         <param id="element_count">
 4303           <jint/>
 4304           <description>
 4305             The length of the primitive array.
 4306           </description>
 4307         </param>
 4308         <param id="element_type">
 4309           <enum>jvmtiPrimitiveType</enum>
 4310           <description>
 4311             The type of the elements of the array.
 4312           </description>
 4313         </param>
 4314         <param id="elements">
 4315           <vmbuf><void/></vmbuf>
 4316           <description>
 4317             The elements of the array in a packed array of <code>element_count</code>
 4318             items of <code>element_type</code> size each.
 4319           </description>
 4320         </param>
 4321         <param id="user_data">
 4322           <outptr><void/></outptr>
 4323           <description>
 4324             The user supplied data that was passed into the iteration function.
 4325           </description>
 4326         </param>
 4327       </parameters>
 4328     </callback>
 4329 
 4330     <callback id="jvmtiStringPrimitiveValueCallback" since="1.1">
 4331       <jint/>
 4332       <synopsis>String Primitive Value Callback</synopsis>
 4333       <description>
 4334         Agent supplied callback function.
 4335         Describes the value of a java.lang.String.
 4336         <p/>
 4337         This function should return a bit vector of the desired
 4338         <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
 4339         This will determine if the entire iteration should be aborted
 4340         (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
 4341         <p/>
 4342         See the <internallink id="heapCallbacks">heap callback
 4343         function restrictions</internallink>.
 4344       </description>
 4345       <parameters>
 4346         <param id="class_tag">
 4347           <jlong/>
 4348           <description>
 4349             The tag of the class of the String class (zero if the class is not tagged).
 4350             <issue>Is this needed?</issue>
 4351           </description>
 4352         </param>
 4353         <param id="size">
 4354           <jlong/>
 4355           <description>
 4356             Size of the string (in bytes).
 4357             See <functionlink id="GetObjectSize"/>.
 4358           </description>
 4359         </param>
 4360         <param id="tag_ptr">
 4361           <outptr><jlong/></outptr>
 4362           <description>
 4363             Points to the tag of the String object, or zero if the object is not
 4364             tagged.
 4365             To set the tag value to be associated with the object
 4366             the agent sets the <code>jlong</code> pointed to by the parameter.
 4367           </description>
 4368         </param>
 4369         <param id="value">
 4370           <vmbuf><jchar/></vmbuf>
 4371           <description>
 4372             The value of the String, encoded as a Unicode string.
 4373           </description>
 4374         </param>
 4375         <param id="value_length">
 4376           <jint/>
 4377           <description>
 4378             The length of the string.
 4379             The length is equal to the number of 16-bit Unicode
 4380             characters in the string.
 4381           </description>
 4382         </param>
 4383         <param id="user_data">
 4384           <outptr><void/></outptr>
 4385           <description>
 4386             The user supplied data that was passed into the iteration function.
 4387           </description>
 4388         </param>
 4389       </parameters>
 4390     </callback>
 4391 
 4392 
 4393     <callback id="jvmtiReservedCallback" since="1.1">
 4394       <jint/>
 4395       <synopsis>reserved for future use Callback</synopsis>
 4396       <description>
 4397         Placeholder -- reserved for future use.
 4398       </description>
 4399       <parameters>
 4400       </parameters>
 4401     </callback>
 4402 
 4403     <function id="FollowReferences" num="115" since="1.1">
 4404       <synopsis>Follow References</synopsis>
 4405       <description>
 4406         This function initiates a traversal over the objects that are
 4407         directly and indirectly reachable from the specified object or,
 4408         if <code>initial_object</code> is not specified, all objects
 4409         reachable from the heap roots.
 4410         The heap root are the set of system classes,
 4411         JNI globals, references from thread stacks, and other objects used as roots
 4412         for the purposes of garbage collection.
 4413         <p/>
 4414         This function operates by traversing the reference graph.
 4415         Let <i>A</i>, <i>B</i>, ... represent objects.
 4416         When a reference from <i>A</i> to <i>B</i> is traversed,
 4417         when a reference from a heap root to <i>B</i> is traversed,
 4418         or when <i>B</i> is specified as the <paramlink id="initial_object"/>,
 4419         then <i>B</i> is said to be <i>visited</i>.
 4420         A reference from <i>A</i> to <i>B</i> is not traversed until <i>A</i>
 4421         is visited.
 4422         References are reported in the same order that the references are traversed.
 4423         Object references are reported by invoking the agent supplied
 4424         callback function <functionlink id="jvmtiHeapReferenceCallback"/>.
 4425         In a reference from <i>A</i> to <i>B</i>, <i>A</i> is known
 4426         as the <i>referrer</i> and <i>B</i> as the <i>referree</i>.
 4427         The callback is invoked exactly once for each reference from a referrer;
 4428         this is true even if there are reference cycles or multiple paths to
 4429         the referrer.
 4430         There may be more than one reference between a referrer and a referree,
 4431         each reference is reported.
 4432         These references may be distinguished by examining the
 4433         <datalink
 4434          id="jvmtiHeapReferenceCallback.reference_kind"><code>reference_kind</code></datalink>
 4435          and
 4436         <datalink
 4437          id="jvmtiHeapReferenceCallback.reference_info"><code>reference_info</code></datalink>
 4438         parameters of the <functionlink id="jvmtiHeapReferenceCallback"/> callback.
 4439         <p/>
 4440         This function reports a Java programming language view of object references,
 4441         not a virtual machine implementation view. The following object references
 4442         are reported when they are non-null:
 4443         <ul>
 4444           <li>Instance objects report references to each non-primitive instance fields
 4445               (including inherited fields).</li>
 4446           <li>Instance objects report a reference to the object type (class).</li>
 4447           <li>Classes report a reference to the superclass and directly
 4448               implemented/extended interfaces.</li>
 4449           <li>Classes report a reference to the class loader, protection domain,
 4450               signers, and resolved entries in the constant pool.</li>
 4451           <li>Classes report a reference to each directly declared non-primitive
 4452               static field.</li>
 4453           <li>Arrays report a reference to the array type (class) and each
 4454               array element.</li>
 4455           <li>Primitive arrays report a reference to the array type.</li>
 4456         </ul>
 4457         <p/>
 4458         This function can also be used to examine primitive (non-object) values.
 4459         The primitive value of an array or String
 4460         is reported after the object has been visited;
 4461         it is reported by invoking the agent supplied callback function
 4462         <functionlink id="jvmtiArrayPrimitiveValueCallback"/> or
 4463         <functionlink id="jvmtiStringPrimitiveValueCallback"/>.
 4464         A primitive field
 4465         is reported after the object with that field is visited;
 4466         it is reported by invoking the agent supplied callback function
 4467         <functionlink id="jvmtiPrimitiveFieldCallback"/>.
 4468         <p/>
 4469         Whether a callback is provided or is <code>NULL</code> only determines
 4470         whether the callback will be invoked, it does not influence
 4471         which objects are visited nor does it influence whether other callbacks
 4472         will be invoked.
 4473         However, the
 4474         <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>
 4475         returned by <functionlink id="jvmtiHeapReferenceCallback"/>
 4476         do determine if the objects referenced by the
 4477         current object as visited.
 4478         The <datalink id="jvmtiHeapFilter">heap filter flags</datalink>
 4479         and <paramlink id="klass"/> provided as parameters to this function
 4480         do not control which objects are visited but they do control which
 4481         objects and primitive values are reported by the callbacks.
 4482         For example, if the only callback that was set is
 4483         <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/> and <code>klass</code>
 4484         is set to the array of bytes class, then only arrays of byte will be
 4485         reported.
 4486         The table below summarizes this:
 4487         <p/>
 4488         <table>
 4489           <tr class="bgLight">
 4490             <th/>
 4491             <th class="centered" scope="col">Controls objects visited</th>
 4492             <th class="centered" scope="col">Controls objects reported</th>
 4493             <th class="centered" scope="col">Controls primitives reported</th>
 4494           </tr>
 4495           <tr>
 4496             <th scope="row">
 4497               the
 4498               <datalink id="jvmtiHeapVisitControl">Heap Visit Control Flags</datalink>
 4499               returned by <functionlink id="jvmtiHeapReferenceCallback"/>
 4500             </th>
 4501             <td class="centered">
 4502               <b>Yes</b>
 4503             </td>
 4504             <td class="centered">
 4505               <b>Yes</b>, since visits are controlled
 4506             </td>
 4507             <td class="centered">
 4508               <b>Yes</b>, since visits are controlled
 4509             </td>
 4510           </tr>
 4511           <tr>
 4512             <th scope="row">
 4513               <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/>
 4514               in <paramlink id="callbacks"/> set
 4515             </th>
 4516             <td class="centered">
 4517               No
 4518             </td>
 4519             <td class="centered">
 4520               <b>Yes</b>
 4521             </td>
 4522             <td class="centered">
 4523               No
 4524             </td>
 4525           </tr>
 4526           <tr>
 4527             <th scope="row">
 4528               <paramlink id="heap_filter"/>
 4529             </th>
 4530             <td class="centered">
 4531               No
 4532             </td>
 4533             <td class="centered">
 4534               <b>Yes</b>
 4535             </td>
 4536             <td class="centered">
 4537               <b>Yes</b>
 4538             </td>
 4539           </tr>
 4540           <tr>
 4541             <th scope="row">
 4542               <paramlink id="klass"/>
 4543             </th>
 4544             <td class="centered">
 4545               No
 4546             </td>
 4547             <td class="centered">
 4548               <b>Yes</b>
 4549             </td>
 4550             <td class="centered">
 4551               <b>Yes</b>
 4552             </td>
 4553           </tr>
 4554         </table>
 4555         <p/>
 4556         During the execution of this function the state of the heap
 4557         does not change: no objects are allocated, no objects are
 4558         garbage collected, and the state of objects (including
 4559         held values) does not change.
 4560         As a result, threads executing Java
 4561         programming language code, threads attempting to resume the
 4562         execution of Java programming language code, and threads
 4563         attempting to execute JNI functions are typically stalled.
 4564       </description>
 4565       <origin>new</origin>
 4566       <capabilities>
 4567         <required id="can_tag_objects"></required>
 4568       </capabilities>
 4569       <parameters>
 4570         <param id="heap_filter">
 4571           <jint/>
 4572           <description>
 4573             This bit vector of
 4574             <datalink id="jvmtiHeapFilter">heap filter flags</datalink>.
 4575             restricts the objects for which the callback function is called.
 4576             This applies to both the object and primitive callbacks.
 4577           </description>
 4578         </param>
 4579         <param id="klass">
 4580           <ptrtype>
 4581             <jclass/>
 4582             <nullok>callbacks are not limited to instances of a particular
 4583                     class</nullok>
 4584           </ptrtype>
 4585           <description>
 4586             Callbacks are only reported when the object is an instance of
 4587             this class.
 4588             Objects which are instances of a subclass of <code>klass</code>
 4589             are not reported.
 4590             If <code>klass</code> is an interface, no objects are reported.
 4591             This applies to both the object and primitive callbacks.
 4592           </description>
 4593         </param>
 4594         <param id="initial_object">
 4595           <ptrtype>
 4596             <jobject/>
 4597             <nullok>references are followed from the heap roots</nullok>
 4598           </ptrtype>
 4599           <description>
 4600             The object to follow
 4601           </description>
 4602         </param>
 4603         <param id="callbacks">
 4604           <inptr>
 4605             <struct>jvmtiHeapCallbacks</struct>
 4606           </inptr>
 4607           <description>
 4608             Structure defining the set of callback functions.
 4609           </description>
 4610         </param>
 4611         <param id="user_data">
 4612           <inbuf>
 4613             <void/>
 4614             <nullok><code>NULL</code> is passed as the user supplied data</nullok>
 4615           </inbuf>
 4616           <description>
 4617             User supplied data to be passed to the callback.
 4618           </description>
 4619         </param>
 4620       </parameters>
 4621       <errors>
 4622         <error id="JVMTI_ERROR_INVALID_CLASS">
 4623           <paramlink id="klass"/> is not a valid class.
 4624         </error>
 4625         <error id="JVMTI_ERROR_INVALID_OBJECT">
 4626           <paramlink id="initial_object"/> is not a valid object.
 4627         </error>
 4628       </errors>
 4629     </function>
 4630 
 4631 
 4632     <function id="IterateThroughHeap" num="116" since="1.1">
 4633       <synopsis>Iterate Through Heap</synopsis>
 4634       <description>
 4635         Initiate an iteration over all objects in the heap.
 4636         This includes both reachable and
 4637         unreachable objects. Objects are visited in no particular order.
 4638         <p/>
 4639         Heap objects are reported by invoking the agent supplied
 4640         callback function <functionlink id="jvmtiHeapIterationCallback"/>.
 4641         References between objects are not reported.
 4642         If only reachable objects are desired, or if object reference information
 4643         is needed, use <functionlink id="FollowReferences"/>.
 4644         <p/>
 4645         This function can also be used to examine primitive (non-object) values.
 4646         The primitive value of an array or String
 4647         is reported after the object has been visited;
 4648         it is reported by invoking the agent supplied callback function
 4649         <functionlink id="jvmtiArrayPrimitiveValueCallback"/> or
 4650         <functionlink id="jvmtiStringPrimitiveValueCallback"/>.
 4651         A primitive field
 4652         is reported after the object with that field is visited;
 4653         it is reported by invoking the agent supplied
 4654         callback function
 4655         <functionlink id="jvmtiPrimitiveFieldCallback"/>.
 4656         <p/>
 4657         Unless the iteration is aborted by the
 4658         <datalink id="jvmtiHeapVisitControl">Heap Visit Control Flags</datalink>
 4659         returned by a callback, all objects in the heap are visited.
 4660         Whether a callback is provided or is <code>NULL</code> only determines
 4661         whether the callback will be invoked, it does not influence
 4662         which objects are visited nor does it influence whether other callbacks
 4663         will be invoked.
 4664         The <datalink id="jvmtiHeapFilter">heap filter flags</datalink>
 4665         and <paramlink id="klass"/> provided as parameters to this function
 4666         do not control which objects are visited but they do control which
 4667         objects and primitive values are reported by the callbacks.
 4668         For example, if the only callback that was set is
 4669         <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/> and <code>klass</code>
 4670         is set to the array of bytes class, then only arrays of byte will be
 4671         reported. The table below summarizes this (contrast this with
 4672         <functionlink id="FollowReferences"/>):
 4673         <p/>
 4674         <table>
 4675           <tr class="bgLight">
 4676             <th/>
 4677             <th class="centered" scope="col">Controls objects visited</th>
 4678             <th class="centered" scope="col">Controls objects reported</th>
 4679             <th class="centered" scope="col">Controls primitives reported</th>
 4680           </tr>
 4681           <tr>
 4682             <th scope="row">
 4683               the
 4684               <datalink id="jvmtiHeapVisitControl">Heap Visit Control Flags</datalink>
 4685               returned by <functionlink id="jvmtiHeapIterationCallback"/>
 4686             </th>
 4687             <td class="centered">
 4688               No<br/>(unless they abort the iteration)
 4689             </td>
 4690             <td class="centered">
 4691               No<br/>(unless they abort the iteration)
 4692             </td>
 4693             <td class="centered">
 4694               No<br/>(unless they abort the iteration)
 4695             </td>
 4696           </tr>
 4697           <tr>
 4698             <th scope="row">
 4699               <fieldlink id="array_primitive_value_callback" struct="jvmtiHeapCallbacks"/>
 4700               in <paramlink id="callbacks"/> set
 4701             </th>
 4702             <td class="centered">
 4703               No
 4704             </td>
 4705             <td class="centered">
 4706               <b>Yes</b>
 4707             </td>
 4708             <td class="centered">
 4709               No
 4710             </td>
 4711           </tr>
 4712           <tr>
 4713             <th scope="row">
 4714               <paramlink id="heap_filter"/>
 4715             </th>
 4716             <td class="centered">
 4717               No
 4718             </td>
 4719             <td class="centered">
 4720               <b>Yes</b>
 4721             </td>
 4722             <td class="centered">
 4723               <b>Yes</b>
 4724             </td>
 4725           </tr>
 4726           <tr>
 4727             <th scope="row">
 4728               <paramlink id="klass"/>
 4729             </th>
 4730             <td class="centered">
 4731               No
 4732             </td>
 4733             <td class="centered">
 4734               <b>Yes</b>
 4735             </td>
 4736             <td class="centered">
 4737               <b>Yes</b>
 4738             </td>
 4739           </tr>
 4740         </table>
 4741         <p/>
 4742         During the execution of this function the state of the heap
 4743         does not change: no objects are allocated, no objects are
 4744         garbage collected, and the state of objects (including
 4745         held values) does not change.
 4746         As a result, threads executing Java
 4747         programming language code, threads attempting to resume the
 4748         execution of Java programming language code, and threads
 4749         attempting to execute JNI functions are typically stalled.
 4750       </description>
 4751       <origin>new</origin>
 4752       <capabilities>
 4753         <required id="can_tag_objects"></required>
 4754       </capabilities>
 4755       <parameters>
 4756         <param id="heap_filter">
 4757           <jint/>
 4758           <description>
 4759             This bit vector of
 4760             <datalink id="jvmtiHeapFilter">heap filter flags</datalink>.
 4761             restricts the objects for which the callback function is called.
 4762             This applies to both the object and primitive callbacks.
 4763           </description>
 4764         </param>
 4765         <param id="klass">
 4766           <ptrtype>
 4767             <jclass/>
 4768             <nullok>callbacks are not limited to instances of a particular class</nullok>
 4769           </ptrtype>
 4770           <description>
 4771             Callbacks are only reported when the object is an instance of
 4772             this class.
 4773             Objects which are instances of a subclass of <code>klass</code>
 4774             are not reported.
 4775             If <code>klass</code> is an interface, no objects are reported.
 4776             This applies to both the object and primitive callbacks.
 4777           </description>
 4778         </param>
 4779         <param id="callbacks">
 4780           <inptr>
 4781             <struct>jvmtiHeapCallbacks</struct>
 4782           </inptr>
 4783           <description>
 4784             Structure defining the set callback functions.
 4785           </description>
 4786         </param>
 4787         <param id="user_data">
 4788           <inbuf>
 4789             <void/>
 4790             <nullok><code>NULL</code> is passed as the user supplied data</nullok>
 4791           </inbuf>
 4792           <description>
 4793             User supplied data to be passed to the callback.
 4794           </description>
 4795         </param>
 4796       </parameters>
 4797       <errors>
 4798         <error id="JVMTI_ERROR_INVALID_CLASS">
 4799           <paramlink id="klass"/> is not a valid class.
 4800         </error>
 4801       </errors>
 4802     </function>
 4803 
 4804     <function id="GetTag" phase="start" num="106">
 4805       <synopsis>Get Tag</synopsis>
 4806       <description>
 4807         Retrieve the tag associated with an object.
 4808         The tag is a long value typically used to store a
 4809         unique identifier or pointer to object information.
 4810         The tag is set with
 4811         <functionlink id="SetTag"></functionlink>.
 4812         Objects for which no tags have been set return a
 4813         tag value of zero.
 4814       </description>
 4815       <origin>new</origin>
 4816       <capabilities>
 4817         <required id="can_tag_objects"></required>
 4818       </capabilities>
 4819       <parameters>
 4820         <param id="object">
 4821           <jobject/>
 4822             <description>
 4823               The object whose tag is to be retrieved.
 4824             </description>
 4825         </param>
 4826         <param id="tag_ptr">
 4827           <outptr><jlong/></outptr>
 4828           <description>
 4829             On return, the referenced long is set to the value
 4830             of the tag.
 4831           </description>
 4832         </param>
 4833       </parameters>
 4834       <errors>
 4835       </errors>
 4836     </function>
 4837 
 4838     <function id="SetTag" phase="start" num="107">
 4839       <synopsis>Set Tag</synopsis>
 4840       <description>
 4841         Set the tag associated with an object.
 4842         The tag is a long value typically used to store a
 4843         unique identifier or pointer to object information.
 4844         The tag is visible with
 4845         <functionlink id="GetTag"></functionlink>.
 4846       </description>
 4847       <origin>new</origin>
 4848       <capabilities>
 4849         <required id="can_tag_objects"></required>
 4850       </capabilities>
 4851       <parameters>
 4852         <param id="object">
 4853           <jobject/>
 4854             <description>
 4855               The object whose tag is to be set.
 4856             </description>
 4857         </param>
 4858         <param id="tag">
 4859           <jlong/>
 4860           <description>
 4861             The new value of the tag.
 4862           </description>
 4863         </param>
 4864       </parameters>
 4865       <errors>
 4866       </errors>
 4867     </function>
 4868 
 4869     <function id="GetObjectsWithTags" num="114">
 4870       <synopsis>Get Objects With Tags</synopsis>
 4871       <description>
 4872         Return objects in the heap with the specified tags.
 4873         The format is parallel arrays of objects and tags.
 4874       </description>
 4875       <origin>new</origin>
 4876       <capabilities>
 4877         <required id="can_tag_objects"></required>
 4878       </capabilities>
 4879       <parameters>
 4880         <param id="tag_count">
 4881           <jint min="0"/>
 4882             <description>
 4883               Number of tags to scan for.
 4884             </description>
 4885         </param>
 4886         <param id="tags">
 4887           <inbuf incount="tag_count">
 4888             <jlong/>
 4889           </inbuf>
 4890             <description>
 4891               Scan for objects with these tags.
 4892               Zero is not permitted in this array.
 4893             </description>
 4894         </param>
 4895         <param id="count_ptr">
 4896           <outptr>
 4897             <jint/>
 4898           </outptr>
 4899             <description>
 4900               Return the number of objects with any of the tags
 4901               in <paramlink id="tags"/>.
 4902             </description>
 4903         </param>
 4904         <param id="object_result_ptr">
 4905           <allocbuf outcount="count_ptr">
 4906             <jobject/>
 4907             <nullok>this information is not returned</nullok>
 4908           </allocbuf>
 4909             <description>
 4910               Returns the array of objects with any of the tags
 4911               in <paramlink id="tags"/>.
 4912             </description>
 4913         </param>
 4914         <param id="tag_result_ptr">
 4915           <allocbuf outcount="count_ptr">
 4916             <jlong/>
 4917             <nullok>this information is not returned</nullok>
 4918           </allocbuf>
 4919             <description>
 4920               For each object in <paramlink id="object_result_ptr"/>,
 4921               return the tag at the corresponding index.
 4922             </description>
 4923         </param>
 4924       </parameters>
 4925       <errors>
 4926         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
 4927           Zero is present in <paramlink id="tags"></paramlink>.
 4928         </error>
 4929       </errors>
 4930     </function>
 4931 
 4932     <function id="ForceGarbageCollection" num="108">
 4933       <synopsis>Force Garbage Collection</synopsis>
 4934       <description>
 4935         Force the VM to perform a garbage collection.
 4936         The garbage collection is as complete as possible.
 4937         This function does not cause finalizers to be run.
 4938         This function does not return until the garbage collection
 4939         is finished.
 4940         <p/>
 4941         Although garbage collection is as complete
 4942         as possible there is no guarantee that all
 4943         <eventlink id="ObjectFree"/>
 4944         events will have been
 4945         sent by the time that this function
 4946         returns. In particular, an object may be
 4947         prevented from being freed because it
 4948         is awaiting finalization.
 4949       </description>
 4950       <origin>new</origin>
 4951       <capabilities>
 4952       </capabilities>
 4953       <parameters>
 4954       </parameters>
 4955       <errors>
 4956       </errors>
 4957     </function>
 4958 
 4959 
 4960   </category>
 4961 
 4962   <category id="Heap_1_0" label="Heap (1.0)">
 4963     <intro>
 4964       <b>
 4965         These functions and data types were introduced in the original
 4966         <jvmti/> version 1.0. They are deprecated and will be changed 
 4967         to return an error in a future release. They were superseded in
 4968         <jvmti/> version 1.2 (Java SE 6) by more 
 4969       </b>
 4970       <internallink id="Heap"><b>powerful and flexible versions</b></internallink>
 4971       <b>
 4972         which:
 4973       </b>
 4974       <ul>
 4975         <li>
 4976           <b>
 4977             Allow access to primitive values (the value of Strings, arrays,
 4978             and primitive fields)
 4979           </b>
 4980         </li>
 4981         <li>
 4982           <b>
 4983             Allow the tag of the referrer to be set, thus enabling more
 4984             efficient localized reference graph building
 4985           </b>
 4986         </li>
 4987         <li>
 4988           <b>
 4989             Provide more extensive filtering abilities
 4990           </b>
 4991         </li>
 4992         <li>
 4993           <b>
 4994             Are extensible, allowing their abilities to grow in future versions of <jvmti/>
 4995           </b>
 4996         </li>
 4997       </ul>
 4998       <p/>
 4999       <b>Please use the </b>
 5000       <internallink id="Heap"><b>current Heap functions</b></internallink>.
 5001         <p/>
 5002         <constants id="jvmtiHeapObjectFilter" label="Heap Object Filter Enumeration" kind="enum">
 5003           <constant id="JVMTI_HEAP_OBJECT_TAGGED" num="1">
 5004             Tagged objects only.
 5005           </constant>
 5006           <constant id="JVMTI_HEAP_OBJECT_UNTAGGED" num="2">
 5007             Untagged objects only.
 5008           </constant>
 5009           <constant id="JVMTI_HEAP_OBJECT_EITHER" num="3">
 5010             Either tagged or untagged objects.
 5011           </constant>
 5012         </constants>
 5013 
 5014         <constants id="jvmtiHeapRootKind" label="Heap Root Kind Enumeration" kind="enum">
 5015           <constant id="JVMTI_HEAP_ROOT_JNI_GLOBAL" num="1">
 5016             JNI global reference.
 5017           </constant>
 5018           <constant id="JVMTI_HEAP_ROOT_SYSTEM_CLASS" num="2">
 5019             System class.
 5020           </constant>
 5021           <constant id="JVMTI_HEAP_ROOT_MONITOR" num="3">
 5022             Monitor.
 5023           </constant>
 5024           <constant id="JVMTI_HEAP_ROOT_STACK_LOCAL" num="4">
 5025             Stack local.
 5026           </constant>
 5027           <constant id="JVMTI_HEAP_ROOT_JNI_LOCAL" num="5">
 5028             JNI local reference.
 5029           </constant>
 5030           <constant id="JVMTI_HEAP_ROOT_THREAD" num="6">
 5031             Thread.
 5032           </constant>
 5033           <constant id="JVMTI_HEAP_ROOT_OTHER" num="7">
 5034             Other.
 5035           </constant>
 5036         </constants>
 5037 
 5038         <constants id="jvmtiObjectReferenceKind" label="Object Reference Enumeration" kind="enum">
 5039           <constant id="JVMTI_REFERENCE_CLASS" num="1">
 5040             Reference from an object to its class.
 5041           </constant>
 5042           <constant id="JVMTI_REFERENCE_FIELD" num="2">
 5043             Reference from an object to the value of one of its instance fields.
 5044             For references of this kind the <code>referrer_index</code>
 5045             parameter to the <internallink id="jvmtiObjectReferenceCallback">
 5046             jvmtiObjectReferenceCallback</internallink> is the index of the
 5047             the instance field. The index is based on the order of all the
 5048             object's fields. This includes all fields of the directly declared
 5049             static and instance fields in the class, and includes all fields (both
 5050             public and private) fields declared in superclasses and superinterfaces.
 5051             The index is thus calculated by summing the index of the field in the directly
 5052             declared class (see <functionlink id="GetClassFields"/>), with the total
 5053             number of fields (both public and private) declared in all superclasses
 5054             and superinterfaces. The index starts at zero.
 5055           </constant>
 5056           <constant id="JVMTI_REFERENCE_ARRAY_ELEMENT" num="3">
 5057             Reference from an array to one of its elements.
 5058             For references of this kind the <code>referrer_index</code>
 5059             parameter to the <internallink id="jvmtiObjectReferenceCallback">
 5060             jvmtiObjectReferenceCallback</internallink> is the array index.
 5061           </constant>
 5062           <constant id="JVMTI_REFERENCE_CLASS_LOADER" num="4">
 5063             Reference from a class to its class loader.
 5064           </constant>
 5065           <constant id="JVMTI_REFERENCE_SIGNERS" num="5">
 5066             Reference from a class to its signers array.
 5067           </constant>
 5068           <constant id="JVMTI_REFERENCE_PROTECTION_DOMAIN" num="6">
 5069             Reference from a class to its protection domain.
 5070           </constant>
 5071           <constant id="JVMTI_REFERENCE_INTERFACE" num="7">
 5072             Reference from a class to one of its interfaces.
 5073           </constant>
 5074           <constant id="JVMTI_REFERENCE_STATIC_FIELD" num="8">
 5075             Reference from a class to the value of one of its static fields.
 5076             For references of this kind the <code>referrer_index</code>
 5077             parameter to the <internallink id="jvmtiObjectReferenceCallback">
 5078             jvmtiObjectReferenceCallback</internallink> is the index of the
 5079             the static field. The index is based on the order of all the
 5080             object's fields. This includes all fields of the directly declared
 5081             static and instance fields in the class, and includes all fields (both
 5082             public and private) fields declared in superclasses and superinterfaces.
 5083             The index is thus calculated by summing the index of the field in the directly
 5084             declared class (see <functionlink id="GetClassFields"/>), with the total
 5085             number of fields (both public and private) declared in all superclasses
 5086             and superinterfaces. The index starts at zero.
 5087             Note: this definition differs from that in the <jvmti/> 1.0 Specification.
 5088             <rationale>No known implementations used the 1.0 definition.</rationale>
 5089           </constant>
 5090           <constant id="JVMTI_REFERENCE_CONSTANT_POOL" num="9">
 5091             Reference from a class to a resolved entry in the constant pool.
 5092             For references of this kind the <code>referrer_index</code>
 5093             parameter to the <internallink id="jvmtiObjectReferenceCallback">
 5094             jvmtiObjectReferenceCallback</internallink> is the index into
 5095             constant pool table of the class, starting at 1. See
 5096             <vmspec chapter="4.4"/>.
 5097           </constant>
 5098         </constants>
 5099 
 5100         <constants id="jvmtiIterationControl" label="Iteration Control Enumeration" kind="enum">
 5101           <constant id="JVMTI_ITERATION_CONTINUE" num="1">
 5102             Continue the iteration.
 5103             If this is a reference iteration, follow the references of this object.
 5104           </constant>
 5105           <constant id="JVMTI_ITERATION_IGNORE" num="2">
 5106             Continue the iteration.
 5107             If this is a reference iteration, ignore the references of this object.
 5108           </constant>
 5109           <constant id="JVMTI_ITERATION_ABORT" num="0">
 5110             Abort the iteration.
 5111           </constant>
 5112         </constants>
 5113     </intro>
 5114 
 5115     <callback id="jvmtiHeapObjectCallback">
 5116       <enum>jvmtiIterationControl</enum>
 5117       <synopsis>Heap Object Callback</synopsis>
 5118       <description>
 5119         Agent supplied callback function.
 5120         Describes (but does not pass in) an object in the heap.
 5121         <p/>
 5122         Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
 5123         or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
 5124         <p/>
 5125         See the <internallink id="heapCallbacks">heap callback
 5126         function restrictions</internallink>.
 5127       </description>
 5128       <parameters>
 5129         <param id="class_tag">
 5130           <jlong/>
 5131           <description>
 5132             The tag of the class of object (zero if the class is not tagged).
 5133             If the object represents a runtime class,
 5134             the <code>class_tag</code> is the tag
 5135             associated with <code>java.lang.Class</code>
 5136             (zero if <code>java.lang.Class</code> is not tagged).
 5137           </description>
 5138         </param>
 5139         <param id="size">
 5140           <jlong/>
 5141           <description>
 5142             Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
 5143           </description>
 5144         </param>
 5145         <param id="tag_ptr">
 5146           <outptr><jlong/></outptr>
 5147           <description>
 5148             The object tag value, or zero if the object is not tagged.
 5149             To set the tag value to be associated with the object
 5150             the agent sets the <code>jlong</code> pointed to by the parameter.
 5151           </description>
 5152         </param>
 5153         <param id="user_data">
 5154           <outptr><void/></outptr>
 5155           <description>
 5156             The user supplied data that was passed into the iteration function.
 5157           </description>
 5158         </param>
 5159       </parameters>
 5160     </callback>
 5161 
 5162     <callback id="jvmtiHeapRootCallback">
 5163       <enum>jvmtiIterationControl</enum>
 5164       <synopsis>Heap Root Object Callback</synopsis>
 5165       <description>
 5166         Agent supplied callback function.
 5167         Describes (but does not pass in) an object that is a root for the purposes
 5168         of garbage collection.
 5169         <p/>
 5170         Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
 5171         <code>JVMTI_ITERATION_IGNORE</code> to continue iteration without pursuing
 5172         references from referree object or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
 5173         <p/>
 5174         See the <internallink id="heapCallbacks">heap callback
 5175         function restrictions</internallink>.
 5176       </description>
 5177       <parameters>
 5178         <param id="root_kind">
 5179           <enum>jvmtiHeapRootKind</enum>
 5180           <description>
 5181             The kind of heap root.
 5182           </description>
 5183         </param>
 5184         <param id="class_tag">
 5185           <jlong/>
 5186           <description>
 5187             The tag of the class of object (zero if the class is not tagged).
 5188             If the object represents a runtime class, the <code>class_tag</code> is the tag
 5189             associated with <code>java.lang.Class</code>
 5190             (zero if <code>java.lang.Class</code> is not tagged).
 5191           </description>
 5192         </param>
 5193         <param id="size">
 5194           <jlong/>
 5195           <description>
 5196             Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
 5197           </description>
 5198         </param>
 5199         <param id="tag_ptr">
 5200           <outptr><jlong/></outptr>
 5201           <description>
 5202             The object tag value, or zero if the object is not tagged.
 5203             To set the tag value to be associated with the object
 5204             the agent sets the <code>jlong</code> pointed to by the parameter.
 5205           </description>
 5206         </param>
 5207         <param id="user_data">
 5208           <outptr><void/></outptr>
 5209           <description>
 5210             The user supplied data that was passed into the iteration function.
 5211           </description>
 5212         </param>
 5213       </parameters>
 5214     </callback>
 5215 
 5216     <callback id="jvmtiStackReferenceCallback">
 5217       <enum>jvmtiIterationControl</enum>
 5218       <synopsis>Stack Reference Object Callback</synopsis>
 5219       <description>
 5220         Agent supplied callback function.
 5221         Describes (but does not pass in) an object on the stack that is a root for
 5222         the purposes of garbage collection.
 5223         <p/>
 5224         Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
 5225         <code>JVMTI_ITERATION_IGNORE</code> to continue iteration without pursuing
 5226         references from referree object or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
 5227         <p/>
 5228         See the <internallink id="heapCallbacks">heap callback
 5229         function restrictions</internallink>.
 5230       </description>
 5231       <parameters>
 5232         <param id="root_kind">
 5233           <enum>jvmtiHeapRootKind</enum>
 5234           <description>
 5235             The kind of root (either <code>JVMTI_HEAP_ROOT_STACK_LOCAL</code> or
 5236             <code>JVMTI_HEAP_ROOT_JNI_LOCAL</code>).
 5237           </description>
 5238         </param>
 5239         <param id="class_tag">
 5240           <jlong/>
 5241           <description>
 5242            The tag of the class of object (zero if the class is not tagged).
 5243            If the object represents a runtime class, the  <code>class_tag</code> is the tag
 5244            associated with <code>java.lang.Class</code>
 5245            (zero if <code>java.lang.Class</code> is not tagged).
 5246           </description>
 5247         </param>
 5248         <param id="size">
 5249           <jlong/>
 5250           <description>
 5251             Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
 5252           </description>
 5253         </param>
 5254         <param id="tag_ptr">
 5255           <outptr><jlong/></outptr>
 5256           <description>
 5257             The object tag value, or zero if the object is not tagged.
 5258             To set the tag value to be associated with the object
 5259             the agent sets the <code>jlong</code> pointed to by the parameter.
 5260           </description>
 5261         </param>
 5262         <param id="thread_tag">
 5263           <jlong/>
 5264           <description>
 5265             The tag of the thread corresponding to this stack, zero if not tagged.
 5266           </description>
 5267         </param>
 5268         <param id="depth">
 5269           <jint/>
 5270           <description>
 5271             The depth of the frame.
 5272           </description>
 5273         </param>
 5274         <param id="method">
 5275           <jmethodID/>
 5276           <description>
 5277             The method executing in this frame.
 5278           </description>
 5279         </param>
 5280         <param id="slot">
 5281           <jint/>
 5282           <description>
 5283             The slot number.
 5284           </description>
 5285         </param>
 5286         <param id="user_data">
 5287           <outptr><void/></outptr>
 5288           <description>
 5289             The user supplied data that was passed into the iteration function.
 5290           </description>
 5291         </param>
 5292       </parameters>
 5293     </callback>
 5294 
 5295     <callback id="jvmtiObjectReferenceCallback">
 5296       <enum>jvmtiIterationControl</enum>
 5297       <synopsis>Object Reference Callback</synopsis>
 5298       <description>
 5299         Agent supplied callback function.
 5300         Describes a reference from an object (the referrer) to another object
 5301         (the referree).
 5302         <p/>
 5303         Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
 5304         <code>JVMTI_ITERATION_IGNORE</code> to continue iteration without pursuing
 5305         references from referree object or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
 5306         <p/>
 5307         See the <internallink id="heapCallbacks">heap callback
 5308         function restrictions</internallink>.
 5309       </description>
 5310       <parameters>
 5311         <param id="reference_kind">
 5312           <enum>jvmtiObjectReferenceKind</enum>
 5313           <description>
 5314             The type of reference.
 5315           </description>
 5316         </param>
 5317         <param id="class_tag">
 5318           <jlong/>
 5319           <description>
 5320             The tag of the class of referree object (zero if the class is not tagged).
 5321             If the referree object represents a runtime class,
 5322             the  <code>class_tag</code> is the tag
 5323             associated with <code>java.lang.Class</code>
 5324             (zero if <code>java.lang.Class</code> is not tagged).
 5325           </description>
 5326         </param>
 5327         <param id="size">
 5328           <jlong/>
 5329           <description>
 5330             Size of the referree object (in bytes).
 5331             See <functionlink id="GetObjectSize"/>.
 5332           </description>
 5333         </param>
 5334         <param id="tag_ptr">
 5335           <outptr><jlong/></outptr>
 5336           <description>
 5337             The referree object tag value, or zero if the object is not
 5338             tagged.
 5339             To set the tag value to be associated with the object
 5340             the agent sets the <code>jlong</code> pointed to by the parameter.
 5341           </description>
 5342         </param>
 5343         <param id="referrer_tag">
 5344           <jlong/>
 5345           <description>
 5346             The tag of the referrer object, or zero if the referrer
 5347             object is not tagged.
 5348           </description>
 5349         </param>
 5350         <param id="referrer_index">
 5351           <jint/>
 5352           <description>
 5353             For references of type <code>JVMTI_REFERENCE_FIELD</code> or
 5354             <code>JVMTI_REFERENCE_STATIC_FIELD</code> the index
 5355             of the field in the referrer object. The index is based on the
 5356             order of all the object's fields - see <internallink
 5357             id="JVMTI_REFERENCE_FIELD">JVMTI_REFERENCE_FIELD</internallink>
 5358             or <internallink
 5359             id="JVMTI_REFERENCE_STATIC_FIELD">JVMTI_REFERENCE_STATIC_FIELD
 5360             </internallink> for further description.
 5361             <p/>
 5362             For references of type <code>JVMTI_REFERENCE_ARRAY_ELEMENT</code>
 5363             the array index - see <internallink id="JVMTI_REFERENCE_ARRAY_ELEMENT">
 5364             JVMTI_REFERENCE_ARRAY_ELEMENT</internallink> for further description.
 5365             <p/>
 5366             For references of type <code>JVMTI_REFERENCE_CONSTANT_POOL</code>
 5367             the index into the constant pool of the class - see
 5368             <internallink id="JVMTI_REFERENCE_CONSTANT_POOL">
 5369             JVMTI_REFERENCE_CONSTANT_POOL</internallink> for further
 5370             description.
 5371             <p/>
 5372             For references of other kinds the <code>referrer_index</code> is
 5373             <code>-1</code>.
 5374           </description>
 5375         </param>
 5376         <param id="user_data">
 5377           <outptr><void/></outptr>
 5378           <description>
 5379             The user supplied data that was passed into the iteration function.
 5380           </description>
 5381         </param>
 5382       </parameters>
 5383     </callback>
 5384 
 5385     <function id="IterateOverObjectsReachableFromObject" num="109">
 5386       <synopsis>Iterate Over Objects Reachable From Object</synopsis>
 5387       <description>
 5388         This function iterates over all objects that are directly
 5389         and indirectly reachable from the specified object.
 5390         For each object <i>A</i> (known
 5391         as the referrer) with a reference to object <i>B</i> the specified
 5392         callback function is called to describe the object reference.
 5393         The callback is called exactly once for each reference from a referrer;
 5394         this is true even if there are reference cycles or multiple paths to
 5395         the referrer.
 5396         There may be more than one reference between a referrer and a referree,
 5397         These may be distinguished by the
 5398         <datalink id="jvmtiObjectReferenceCallback.reference_kind"></datalink> and
 5399         <datalink id="jvmtiObjectReferenceCallback.referrer_index"></datalink>.
 5400         The callback for an object will always occur after the callback for
 5401         its referrer.
 5402         <p/>
 5403         See <functionlink id="FollowReferences"/> for the object
 5404         references which are reported.
 5405         <p/>
 5406         During the execution of this function the state of the heap
 5407         does not change: no objects are allocated, no objects are
 5408         garbage collected, and the state of objects (including
 5409         held values) does not change.
 5410         As a result, threads executing Java
 5411         programming language code, threads attempting to resume the
 5412         execution of Java programming language code, and threads
 5413         attempting to execute JNI functions are typically stalled.
 5414       </description>
 5415       <origin>new</origin>
 5416       <capabilities>
 5417         <required id="can_tag_objects"></required>
 5418       </capabilities>
 5419       <parameters>
 5420         <param id="object">
 5421           <jobject/>
 5422             <description>
 5423               The object
 5424             </description>
 5425         </param>
 5426         <param id="object_reference_callback">
 5427           <ptrtype>
 5428             <struct>jvmtiObjectReferenceCallback</struct>
 5429           </ptrtype>
 5430             <description>
 5431               The callback to be called to describe each
 5432               object reference.
 5433             </description>
 5434         </param>
 5435         <param id="user_data">
 5436           <inbuf>
 5437             <void/>
 5438             <nullok><code>NULL</code> is passed as the user supplied data</nullok>
 5439           </inbuf>
 5440           <description>
 5441             User supplied data to be passed to the callback.
 5442           </description>
 5443         </param>
 5444       </parameters>
 5445       <errors>
 5446       </errors>
 5447     </function>
 5448 
 5449     <function id="IterateOverReachableObjects" num="110">
 5450       <synopsis>Iterate Over Reachable Objects</synopsis>
 5451       <description>
 5452         This function iterates over the root objects and all objects that
 5453         are directly and indirectly reachable from the root objects.
 5454         The root objects comprise the set of system classes,
 5455         JNI globals, references from thread stacks, and other objects used as roots
 5456         for the purposes of garbage collection.
 5457         <p/>
 5458         For each root the <paramlink id="heap_root_callback"></paramlink>
 5459         or <paramlink id="stack_ref_callback"></paramlink> callback is called.
 5460         An object can be a root object for more than one reason and in that case
 5461         the appropriate callback is called for each reason.
 5462         <p/>
 5463         For each object reference the <paramlink id="object_ref_callback"></paramlink>
 5464         callback function is called to describe the object reference.
 5465         The callback is called exactly once for each reference from a referrer;
 5466         this is true even if there are reference cycles or multiple paths to
 5467         the referrer.
 5468         There may be more than one reference between a referrer and a referree,
 5469         These may be distinguished by the
 5470         <datalink id="jvmtiObjectReferenceCallback.reference_kind"></datalink> and
 5471         <datalink id="jvmtiObjectReferenceCallback.referrer_index"></datalink>.
 5472         The callback for an object will always occur after the callback for
 5473         its referrer.
 5474         <p/>
 5475         See <functionlink id="FollowReferences"/> for the object
 5476         references which are reported.
 5477         <p/>
 5478         Roots are always reported to the profiler before any object references
 5479         are reported. In other words, the <paramlink id="object_ref_callback"></paramlink>
 5480         callback will not be called until the appropriate callback has been called
 5481         for all roots. If the <paramlink id="object_ref_callback"></paramlink> callback is
 5482         specified as <code>NULL</code> then this function returns after
 5483         reporting the root objects to the profiler.
 5484         <p/>
 5485         During the execution of this function the state of the heap
 5486         does not change: no objects are allocated, no objects are
 5487         garbage collected, and the state of objects (including
 5488         held values) does not change.
 5489         As a result, threads executing Java
 5490         programming language code, threads attempting to resume the
 5491         execution of Java programming language code, and threads
 5492         attempting to execute JNI functions are typically stalled.
 5493       </description>
 5494       <origin>new</origin>
 5495       <capabilities>
 5496         <required id="can_tag_objects"></required>
 5497       </capabilities>
 5498       <parameters>
 5499         <param id="heap_root_callback">
 5500           <ptrtype>
 5501             <struct>jvmtiHeapRootCallback</struct>
 5502             <nullok>do not report heap roots</nullok>
 5503           </ptrtype>
 5504             <description>
 5505               The callback function to be called for each heap root of type
 5506               <code>JVMTI_HEAP_ROOT_JNI_GLOBAL</code>,
 5507               <code>JVMTI_HEAP_ROOT_SYSTEM_CLASS</code>,
 5508               <code>JVMTI_HEAP_ROOT_MONITOR</code>,
 5509               <code>JVMTI_HEAP_ROOT_THREAD</code>, or
 5510               <code>JVMTI_HEAP_ROOT_OTHER</code>.
 5511             </description>
 5512         </param>
 5513         <param id="stack_ref_callback">
 5514           <ptrtype>
 5515             <struct>jvmtiStackReferenceCallback</struct>
 5516             <nullok>do not report stack references</nullok>
 5517           </ptrtype>
 5518             <description>
 5519               The callback function to be called for each heap root of
 5520               <code>JVMTI_HEAP_ROOT_STACK_LOCAL</code> or
 5521               <code>JVMTI_HEAP_ROOT_JNI_LOCAL</code>.
 5522             </description>
 5523         </param>
 5524         <param id="object_ref_callback">
 5525           <ptrtype>
 5526             <struct>jvmtiObjectReferenceCallback</struct>
 5527             <nullok>do not follow references from the root objects</nullok>
 5528           </ptrtype>
 5529             <description>
 5530               The callback function to be called for each object reference.
 5531             </description>
 5532         </param>
 5533         <param id="user_data">
 5534           <inbuf>
 5535             <void/>
 5536             <nullok><code>NULL</code> is passed as the user supplied data</nullok>
 5537           </inbuf>
 5538           <description>
 5539             User supplied data to be passed to the callback.
 5540           </description>
 5541         </param>
 5542       </parameters>
 5543       <errors>
 5544       </errors>
 5545     </function>
 5546 
 5547     <function id="IterateOverHeap" num="111">
 5548       <synopsis>Iterate Over Heap</synopsis>
 5549       <description>
 5550         Iterate over all objects in the heap. This includes both reachable and
 5551         unreachable objects.
 5552         <p/>
 5553         The <paramlink id="object_filter"></paramlink> parameter indicates the
 5554         objects for which the callback function is called. If this parameter
 5555         is <code>JVMTI_HEAP_OBJECT_TAGGED</code> then the callback will only be
 5556         called for every object that is tagged. If the parameter is
 5557         <code>JVMTI_HEAP_OBJECT_UNTAGGED</code> then the callback will only be
 5558         for objects that are not tagged. If the parameter
 5559         is <code>JVMTI_HEAP_OBJECT_EITHER</code> then the callback will be
 5560         called for every object in the heap, irrespective of whether it is
 5561         tagged or not.
 5562         <p/>
 5563         During the execution of this function the state of the heap
 5564         does not change: no objects are allocated, no objects are
 5565         garbage collected, and the state of objects (including
 5566         held values) does not change.
 5567         As a result, threads executing Java
 5568         programming language code, threads attempting to resume the
 5569         execution of Java programming language code, and threads
 5570         attempting to execute JNI functions are typically stalled.
 5571       </description>
 5572       <origin>new</origin>
 5573       <capabilities>
 5574         <required id="can_tag_objects"></required>
 5575       </capabilities>
 5576       <parameters>
 5577         <param id="object_filter">
 5578           <enum>jvmtiHeapObjectFilter</enum>
 5579           <description>
 5580             Indicates the objects for which the callback function is called.
 5581           </description>
 5582         </param>
 5583         <param id="heap_object_callback">
 5584           <ptrtype>
 5585             <struct>jvmtiHeapObjectCallback</struct>
 5586           </ptrtype>
 5587             <description>
 5588               The iterator function to be called for each
 5589               object matching the <paramlink id="object_filter"/>.
 5590             </description>
 5591         </param>
 5592         <param id="user_data">
 5593           <inbuf>
 5594             <void/>
 5595             <nullok><code>NULL</code> is passed as the user supplied data</nullok>
 5596           </inbuf>
 5597           <description>
 5598             User supplied data to be passed to the callback.
 5599           </description>
 5600         </param>
 5601       </parameters>
 5602       <errors>
 5603       </errors>
 5604     </function>
 5605 
 5606     <function id="IterateOverInstancesOfClass" num="112">
 5607       <synopsis>Iterate Over Instances Of Class</synopsis>
 5608       <description>
 5609         Iterate over all objects in the heap that are instances of the specified class.
 5610         This includes direct instances of the specified class and
 5611         instances of all subclasses of the specified class.
 5612         This includes both reachable and unreachable objects.
 5613         <p/>
 5614         The <paramlink id="object_filter"></paramlink> parameter indicates the
 5615         objects for which the callback function is called. If this parameter
 5616         is <code>JVMTI_HEAP_OBJECT_TAGGED</code> then the callback will only be
 5617         called for every object that is tagged. If the parameter is
 5618         <code>JVMTI_HEAP_OBJECT_UNTAGGED</code> then the callback will only be
 5619         called for objects that are not tagged. If the parameter
 5620         is <code>JVMTI_HEAP_OBJECT_EITHER</code> then the callback will be
 5621         called for every object in the heap, irrespective of whether it is
 5622         tagged or not.
 5623         <p/>
 5624         During the execution of this function the state of the heap
 5625         does not change: no objects are allocated, no objects are
 5626         garbage collected, and the state of objects (including
 5627         held values) does not change.
 5628         As a result, threads executing Java
 5629         programming language code, threads attempting to resume the
 5630         execution of Java programming language code, and threads
 5631         attempting to execute JNI functions are typically stalled.
 5632       </description>
 5633       <origin>new</origin>
 5634       <capabilities>
 5635         <required id="can_tag_objects"></required>
 5636       </capabilities>
 5637       <parameters>
 5638         <param id="klass">
 5639           <jclass/>
 5640             <description>
 5641               Iterate over objects of this class only.
 5642             </description>
 5643         </param>
 5644         <param id="object_filter">
 5645           <enum>jvmtiHeapObjectFilter</enum>
 5646           <description>
 5647             Indicates the objects for which the callback function is called.
 5648           </description>
 5649         </param>
 5650         <param id="heap_object_callback">
 5651           <ptrtype>
 5652             <struct>jvmtiHeapObjectCallback</struct>
 5653           </ptrtype>
 5654             <description>
 5655               The iterator function to be called for each
 5656               <paramlink id="klass"/> instance matching
 5657               the <paramlink id="object_filter"/>.
 5658             </description>
 5659         </param>
 5660         <param id="user_data">
 5661           <inbuf>
 5662             <void/>
 5663             <nullok><code>NULL</code> is passed as the user supplied data</nullok>
 5664           </inbuf>
 5665           <description>
 5666             User supplied data to be passed to the callback.
 5667           </description>
 5668         </param>
 5669       </parameters>
 5670       <errors>
 5671       </errors>
 5672     </function>
 5673 
 5674   </category>
 5675 
 5676   <category id="local" label="Local Variable">
 5677 
 5678     <intro>
 5679       These functions are used to retrieve or set the value of a local variable.
 5680       The variable is identified by the depth of the frame containing its
 5681       value and the variable's slot number within that frame.
 5682       The mapping of variables to
 5683       slot numbers can be obtained with the function
 5684       <functionlink id="GetLocalVariableTable"></functionlink>.
 5685     </intro>
 5686 
 5687     <function id="GetLocalObject" num="21">
 5688       <synopsis>Get Local Variable - Object</synopsis>
 5689       <description>
 5690         This function can be used to retrieve the value of a local
 5691         variable whose type is <code>Object</code> or a subclass of <code>Object</code>.
 5692       </description>
 5693       <origin>jvmdi</origin>
 5694       <capabilities>
 5695         <required id="can_access_local_variables"></required>
 5696       </capabilities>
 5697       <parameters>
 5698         <param id="thread">
 5699           <jthread null="current" frame="frame"/>
 5700           <description>
 5701             The thread of the frame containing the variable's value.
 5702           </description>
 5703         </param>
 5704         <param id="depth">
 5705           <jframeID thread="thread"/>
 5706           <description>
 5707             The depth of the frame containing the variable's value.
 5708           </description>
 5709         </param>
 5710         <param id="slot">
 5711           <jint/>
 5712           <description>
 5713             The variable's slot number.
 5714           </description>
 5715         </param>
 5716         <param id="value_ptr">
 5717           <outptr><jobject/></outptr>
 5718             <description>
 5719               On return, points to the variable's value.
 5720             </description>
 5721         </param>
 5722       </parameters>
 5723       <errors>
 5724         <error id="JVMTI_ERROR_INVALID_SLOT">
 5725           Invalid <code>slot</code>.
 5726         </error>
 5727         <error id="JVMTI_ERROR_TYPE_MISMATCH">
 5728           The variable type is not
 5729           <code>Object</code> or a subclass of <code>Object</code>.
 5730         </error>
 5731         <error id="JVMTI_ERROR_OPAQUE_FRAME">
 5732           Not a visible frame
 5733         </error>
 5734       </errors>
 5735     </function>
 5736 
 5737     <function id="GetLocalInstance" num="155" since="1.2">
 5738       <synopsis>Get Local Instance</synopsis>
 5739       <description>
 5740         This function can be used to retrieve the value of the local object
 5741         variable at slot 0 (the "<code>this</code>" object) from non-static
 5742         frames.  This function can retrieve the "<code>this</code>" object from
 5743         native method frames, whereas <code>GetLocalObject()</code> would
 5744         return <code>JVMTI_ERROR_OPAQUE_FRAME</code> in those cases.
 5745       </description>
 5746       <origin>new</origin>
 5747       <capabilities>
 5748         <required id="can_access_local_variables"></required>
 5749       </capabilities>
 5750       <parameters>
 5751         <param id="thread">
 5752           <jthread null="current" frame="frame"/>
 5753           <description>
 5754             The thread of the frame containing the variable's value.
 5755           </description>
 5756         </param>
 5757         <param id="depth">
 5758           <jframeID thread="thread"/>
 5759           <description>
 5760             The depth of the frame containing the variable's value.
 5761           </description>
 5762         </param>
 5763         <param id="value_ptr">
 5764           <outptr><jobject/></outptr>
 5765             <description>
 5766               On return, points to the variable's value.
 5767             </description>
 5768         </param>
 5769       </parameters>
 5770       <errors>
 5771         <error id="JVMTI_ERROR_INVALID_SLOT">
 5772           If the specified frame is a static method frame.
 5773         </error>
 5774       </errors>
 5775     </function>
 5776     <function id="GetLocalInt" num="22">
 5777       <synopsis>Get Local Variable - Int</synopsis>
 5778       <description>
 5779         This function can be used to retrieve the value of a local
 5780         variable whose type is <code>int</code>,
 5781         <code>short</code>, <code>char</code>, <code>byte</code>, or
 5782         <code>boolean</code>.
 5783       </description>
 5784       <origin>jvmdi</origin>
 5785       <capabilities>
 5786         <required id="can_access_local_variables"></required>
 5787       </capabilities>
 5788       <parameters>
 5789         <param id="thread">
 5790           <jthread null="current" frame="frame"/>
 5791           <description>
 5792             The thread of the frame containing the variable's value.
 5793           </description>
 5794         </param>
 5795         <param id="depth">
 5796           <jframeID thread="thread"/>
 5797           <description>
 5798             The depth of the frame containing the variable's value.
 5799           </description>
 5800         </param>
 5801         <param id="slot">
 5802           <jint/>
 5803           <description>
 5804             The variable's slot number.
 5805           </description>
 5806         </param>
 5807         <param id="value_ptr">
 5808           <outptr><jint/></outptr>
 5809           <description>
 5810             On return, points to the variable's value.
 5811           </description>
 5812         </param>
 5813       </parameters>
 5814       <errors>
 5815         <error id="JVMTI_ERROR_INVALID_SLOT">
 5816           Invalid <code>slot</code>.
 5817         </error>
 5818         <error id="JVMTI_ERROR_TYPE_MISMATCH">
 5819           The variable type is not
 5820           <code>int</code>, <code>short</code>,
 5821           <code>char</code>, <code>byte</code>, or
 5822           <code>boolean</code>.
 5823         </error>
 5824         <error id="JVMTI_ERROR_OPAQUE_FRAME">
 5825           Not a visible frame
 5826         </error>
 5827       </errors>
 5828     </function>
 5829 
 5830     <function id="GetLocalLong" num="23">
 5831       <synopsis>Get Local Variable - Long</synopsis>
 5832       <description>
 5833         This function can be used to retrieve the value of a local
 5834         variable whose type is <code>long</code>.
 5835       </description>
 5836       <origin>jvmdi</origin>
 5837       <capabilities>
 5838         <required id="can_access_local_variables"></required>
 5839       </capabilities>
 5840       <parameters>
 5841         <param id="thread">
 5842           <jthread null="current" frame="frame"/>
 5843           <description>
 5844             The thread of the frame containing the variable's value.
 5845           </description>
 5846         </param>
 5847         <param id="depth">
 5848           <jframeID thread="thread"/>
 5849           <description>
 5850             The depth of the frame containing the variable's value.
 5851           </description>
 5852         </param>
 5853         <param id="slot">
 5854           <jint/>
 5855           <description>
 5856             The variable's slot number.
 5857           </description>
 5858         </param>
 5859         <param id="value_ptr">
 5860           <outptr><jlong/></outptr>
 5861           <description>
 5862             On return, points to the variable's value.
 5863           </description>
 5864         </param>
 5865       </parameters>
 5866       <errors>
 5867         <error id="JVMTI_ERROR_INVALID_SLOT">
 5868           Invalid <code>slot</code>.
 5869         </error>
 5870         <error id="JVMTI_ERROR_TYPE_MISMATCH">
 5871           The variable type is not <code>long</code>.
 5872         </error>
 5873         <error id="JVMTI_ERROR_OPAQUE_FRAME">
 5874           Not a visible frame
 5875         </error>
 5876       </errors>
 5877     </function>
 5878 
 5879     <function id="GetLocalFloat" num="24">
 5880       <synopsis>Get Local Variable - Float</synopsis>
 5881       <description>
 5882         This function can be used to retrieve the value of a local
 5883         variable whose type is <code>float</code>.
 5884       </description>
 5885       <origin>jvmdi</origin>
 5886       <capabilities>
 5887         <required id="can_access_local_variables"></required>
 5888       </capabilities>
 5889       <parameters>
 5890         <param id="thread">
 5891           <jthread null="current" frame="frame"/>
 5892           <description>
 5893             The thread of the frame containing the variable's value.
 5894           </description>
 5895         </param>
 5896         <param id="depth">
 5897           <jframeID thread="thread"/>
 5898           <description>
 5899             The depth of the frame containing the variable's value.
 5900           </description>
 5901         </param>
 5902         <param id="slot">
 5903           <jint/>
 5904           <description>
 5905             The variable's slot number.
 5906           </description>
 5907         </param>
 5908         <param id="value_ptr">
 5909           <outptr><jfloat/></outptr>
 5910           <description>
 5911             On return, points to the variable's value.
 5912           </description>
 5913         </param>
 5914       </parameters>
 5915       <errors>
 5916         <error id="JVMTI_ERROR_INVALID_SLOT">
 5917           Invalid <code>slot</code>.
 5918         </error>
 5919         <error id="JVMTI_ERROR_TYPE_MISMATCH">
 5920           The variable type is not <code>float</code>.
 5921         </error>
 5922         <error id="JVMTI_ERROR_OPAQUE_FRAME">
 5923           Not a visible frame
 5924         </error>
 5925       </errors>
 5926     </function>
 5927 
 5928     <function id="GetLocalDouble" num="25">
 5929       <synopsis>Get Local Variable - Double</synopsis>
 5930       <description>
 5931         This function can be used to retrieve the value of a local
 5932         variable whose type is <code>long</code>.
 5933       </description>
 5934       <origin>jvmdi</origin>
 5935       <capabilities>
 5936         <required id="can_access_local_variables"></required>
 5937       </capabilities>
 5938       <parameters>
 5939         <param id="thread">
 5940           <jthread null="current" frame="frame"/>
 5941           <description>
 5942             The thread of the frame containing the variable's value.
 5943           </description>
 5944         </param>
 5945         <param id="depth">
 5946           <jframeID thread="thread"/>
 5947           <description>
 5948             The depth of the frame containing the variable's value.
 5949           </description>
 5950         </param>
 5951         <param id="slot">
 5952           <jint/>
 5953           <description>
 5954             The variable's slot number.
 5955           </description>
 5956         </param>
 5957         <param id="value_ptr">
 5958           <outptr><jdouble/></outptr>
 5959           <description>
 5960             On return, points to the variable's value.
 5961           </description>
 5962         </param>
 5963       </parameters>
 5964       <errors>
 5965         <error id="JVMTI_ERROR_INVALID_SLOT">
 5966           Invalid <code>slot</code>.
 5967         </error>
 5968         <error id="JVMTI_ERROR_TYPE_MISMATCH">
 5969           The variable type is not <code>double</code>.
 5970         </error>
 5971         <error id="JVMTI_ERROR_OPAQUE_FRAME">
 5972           Not a visible frame
 5973         </error>
 5974       </errors>
 5975     </function>
 5976 
 5977     <function id="SetLocalObject" num="26">
 5978       <synopsis>Set Local Variable - Object</synopsis>
 5979       <description>
 5980         This function can be used to set the value of a local
 5981         variable whose type is <code>Object</code> or a subclass of <code>Object</code>.
 5982       </description>
 5983       <origin>jvmdi</origin>
 5984       <capabilities>
 5985         <required id="can_access_local_variables"></required>
 5986       </capabilities>
 5987       <parameters>
 5988         <param id="thread">
 5989           <jthread null="current" frame="frame"/>
 5990           <description>
 5991             The thread of the frame containing the variable's value.
 5992           </description>
 5993         </param>
 5994         <param id="depth">
 5995           <jframeID thread="thread"/>
 5996           <description>
 5997             The depth of the frame containing the variable's value.
 5998           </description>
 5999         </param>
 6000         <param id="slot">
 6001           <jint/>
 6002           <description>
 6003             The variable's slot number.
 6004           </description>
 6005         </param>
 6006         <param id="value">
 6007           <jobject/>
 6008             <description>
 6009               The new value for the variable.
 6010             </description>
 6011         </param>
 6012       </parameters>
 6013       <errors>
 6014         <error id="JVMTI_ERROR_INVALID_SLOT">
 6015           Invalid <code>slot</code>.
 6016         </error>
 6017         <error id="JVMTI_ERROR_TYPE_MISMATCH">
 6018           The variable type is not
 6019           <code>Object</code> or a subclass of <code>Object</code>.
 6020         </error>
 6021         <error id="JVMTI_ERROR_TYPE_MISMATCH">
 6022           The supplied <paramlink id="value"/> is not compatible
 6023           with the variable type.
 6024         </error>
 6025         <error id="JVMTI_ERROR_OPAQUE_FRAME">
 6026           Not a visible frame
 6027         </error>
 6028       </errors>
 6029     </function>
 6030 
 6031     <function id="SetLocalInt" num="27">
 6032       <synopsis>Set Local Variable - Int</synopsis>
 6033       <description>
 6034         This function can be used to set the value of a local
 6035         variable whose type is <code>int</code>,
 6036         <code>short</code>, <code>char</code>, <code>byte</code>, or
 6037         <code>boolean</code>.
 6038       </description>
 6039       <origin>jvmdi</origin>
 6040       <capabilities>
 6041         <required id="can_access_local_variables"></required>
 6042       </capabilities>
 6043       <parameters>
 6044         <param id="thread">
 6045           <jthread null="current" frame="frame"/>
 6046           <description>
 6047             The thread of the frame containing the variable's value.
 6048           </description>
 6049         </param>
 6050         <param id="depth">
 6051           <jframeID thread="thread"/>
 6052           <description>
 6053             The depth of the frame containing the variable's value.
 6054           </description>
 6055         </param>
 6056         <param id="slot">
 6057           <jint/>
 6058           <description>
 6059             The variable's slot number.
 6060           </description>
 6061         </param>
 6062         <param id="value">
 6063           <jint/>
 6064           <description>
 6065             The new value for the variable.
 6066           </description>
 6067         </param>
 6068       </parameters>
 6069       <errors>
 6070         <error id="JVMTI_ERROR_INVALID_SLOT">
 6071           Invalid <code>slot</code>.
 6072         </error>
 6073         <error id="JVMTI_ERROR_TYPE_MISMATCH">
 6074           The variable type is not
 6075           <code>int</code>, <code>short</code>,
 6076           <code>char</code>, <code>byte</code>, or
 6077           <code>boolean</code>.
 6078         </error>
 6079         <error id="JVMTI_ERROR_OPAQUE_FRAME">
 6080           Not a visible frame
 6081         </error>
 6082       </errors>
 6083     </function>
 6084 
 6085     <function id="SetLocalLong" num="28">
 6086       <synopsis>Set Local Variable - Long</synopsis>
 6087       <description>
 6088         This function can be used to set the value of a local
 6089         variable whose type is <code>long</code>.
 6090       </description>
 6091       <origin>jvmdi</origin>
 6092       <capabilities>
 6093         <required id="can_access_local_variables"></required>
 6094       </capabilities>
 6095       <parameters>
 6096         <param id="thread">
 6097           <jthread null="current" frame="frame"/>
 6098           <description>
 6099             The thread of the frame containing the variable's value.
 6100           </description>
 6101         </param>
 6102         <param id="depth">
 6103           <jframeID thread="thread"/>
 6104           <description>
 6105             The depth of the frame containing the variable's value.
 6106           </description>
 6107         </param>
 6108         <param id="slot">
 6109           <jint/>
 6110           <description>
 6111             The variable's slot number.
 6112           </description>
 6113         </param>
 6114         <param id="value">
 6115           <jlong/>
 6116           <description>
 6117             The new value for the variable.
 6118           </description>
 6119         </param>
 6120       </parameters>
 6121       <errors>
 6122         <error id="JVMTI_ERROR_INVALID_SLOT">
 6123           Invalid <code>slot</code>.
 6124         </error>
 6125         <error id="JVMTI_ERROR_TYPE_MISMATCH">
 6126           The variable type is not <code>long</code>.
 6127         </error>
 6128         <error id="JVMTI_ERROR_OPAQUE_FRAME">
 6129           Not a visible frame
 6130         </error>
 6131       </errors>
 6132     </function>
 6133 
 6134     <function id="SetLocalFloat" num="29">
 6135       <synopsis>Set Local Variable - Float</synopsis>
 6136       <description>
 6137         This function can be used to set the value of a local
 6138         variable whose type is <code>float</code>.
 6139       </description>
 6140       <origin>jvmdi</origin>
 6141       <capabilities>
 6142         <required id="can_access_local_variables"></required>
 6143       </capabilities>
 6144       <parameters>
 6145         <param id="thread">
 6146           <jthread null="current" frame="frame"/>
 6147           <description>
 6148             The thread of the frame containing the variable's value.
 6149           </description>
 6150         </param>
 6151         <param id="depth">
 6152           <jframeID thread="thread"/>
 6153           <description>
 6154             The depth of the frame containing the variable's value.
 6155           </description>
 6156         </param>
 6157         <param id="slot">
 6158           <jint/>
 6159           <description>
 6160             The variable's slot number.
 6161           </description>
 6162         </param>
 6163         <param id="value">
 6164           <jfloat/>
 6165           <description>
 6166             The new value for the variable.
 6167           </description>
 6168         </param>
 6169       </parameters>
 6170       <errors>
 6171         <error id="JVMTI_ERROR_INVALID_SLOT">
 6172           Invalid <code>slot</code>.
 6173         </error>
 6174         <error id="JVMTI_ERROR_TYPE_MISMATCH">
 6175           The variable type is not <code>float</code>.
 6176         </error>
 6177         <error id="JVMTI_ERROR_OPAQUE_FRAME">
 6178           Not a visible frame
 6179         </error>
 6180       </errors>
 6181     </function>
 6182 
 6183     <function id="SetLocalDouble" num="30">
 6184       <synopsis>Set Local Variable - Double</synopsis>
 6185       <description>
 6186         This function can be used to set the value of a local
 6187         variable whose type is <code>double</code>.
 6188       </description>
 6189       <origin>jvmdi</origin>
 6190       <capabilities>
 6191         <required id="can_access_local_variables"></required>
 6192       </capabilities>
 6193       <parameters>
 6194         <param id="thread">
 6195           <jthread null="current" frame="frame"/>
 6196           <description>
 6197             The thread of the frame containing the variable's value.
 6198           </description>
 6199         </param>
 6200         <param id="depth">
 6201           <jframeID thread="thread"/>
 6202           <description>
 6203             The depth of the frame containing the variable's value.
 6204           </description>
 6205         </param>
 6206         <param id="slot">
 6207           <jint/>
 6208           <description>
 6209             The variable's slot number.
 6210           </description>
 6211         </param>
 6212         <param id="value">
 6213           <jdouble/>
 6214           <description>
 6215             The new value for the variable.
 6216           </description>
 6217         </param>
 6218       </parameters>
 6219       <errors>
 6220         <error id="JVMTI_ERROR_INVALID_SLOT">
 6221           Invalid <code>slot</code>.
 6222         </error>
 6223         <error id="JVMTI_ERROR_TYPE_MISMATCH">
 6224           The variable type is not <code>double</code>.
 6225         </error>
 6226         <error id="JVMTI_ERROR_OPAQUE_FRAME">
 6227           Not a visible frame
 6228         </error>
 6229       </errors>
 6230     </function>
 6231   </category>
 6232 
 6233   <category id="breakpointCategory" label="Breakpoint">
 6234 
 6235     <intro>
 6236     </intro>
 6237 
 6238     <function id="SetBreakpoint" num="38">
 6239       <synopsis>Set Breakpoint</synopsis>
 6240       <description>
 6241         Set a breakpoint at the instruction indicated by
 6242         <code>method</code> and <code>location</code>.
 6243         An instruction can only have one breakpoint.
 6244         <p/>
 6245         Whenever the designated instruction is about to be executed, a
 6246         <eventlink id="Breakpoint"></eventlink> event is generated.
 6247       </description>
 6248       <origin>jvmdi</origin>
 6249       <capabilities>
 6250         <required id="can_generate_breakpoint_events"></required>
 6251       </capabilities>
 6252       <parameters>
 6253         <param id="klass">
 6254           <jclass method="method"/>
 6255             <description>
 6256               The class in which to set the breakpoint
 6257             </description>
 6258         </param>
 6259         <param id="method">
 6260           <jmethodID class="klass"/>
 6261             <description>
 6262               The method in which to set the breakpoint
 6263             </description>
 6264         </param>
 6265         <param id="location">
 6266           <jlocation/>
 6267           <description>
 6268             the index of the instruction at which to set the breakpoint
 6269 
 6270           </description>
 6271         </param>
 6272       </parameters>
 6273       <errors>
 6274         <error id="JVMTI_ERROR_DUPLICATE">
 6275           The designated bytecode already has a breakpoint.
 6276         </error>
 6277       </errors>
 6278     </function>
 6279 
 6280     <function id="ClearBreakpoint" num="39">
 6281       <synopsis>Clear Breakpoint</synopsis>
 6282       <description>
 6283         Clear the breakpoint at the bytecode indicated by
 6284         <code>method</code> and <code>location</code>.
 6285       </description>
 6286       <origin>jvmdi</origin>
 6287       <capabilities>
 6288         <required id="can_generate_breakpoint_events"></required>
 6289       </capabilities>
 6290       <parameters>
 6291         <param id="klass">
 6292           <jclass method="method"/>
 6293             <description>
 6294               The class in which to clear the breakpoint
 6295             </description>
 6296         </param>
 6297         <param id="method">
 6298           <jmethodID class="klass"/>
 6299             <description>
 6300               The method in which to clear the breakpoint
 6301             </description>
 6302         </param>
 6303         <param id="location">
 6304           <jlocation/>
 6305           <description>
 6306             the index of the instruction at which to clear the breakpoint
 6307           </description>
 6308         </param>
 6309       </parameters>
 6310       <errors>
 6311         <error id="JVMTI_ERROR_NOT_FOUND">
 6312           There's no breakpoint at the designated bytecode.
 6313         </error>
 6314       </errors>
 6315     </function>
 6316 
 6317   </category>
 6318 
 6319   <category id="fieldWatch" label="Watched Field">
 6320 
 6321     <intro>
 6322     </intro>
 6323 
 6324     <function id="SetFieldAccessWatch" num="41">
 6325       <synopsis>Set Field Access Watch</synopsis>
 6326       <description>
 6327         Generate a <eventlink id="FieldAccess"></eventlink> event
 6328         when the field specified
 6329         by <code>klass</code> and
 6330         <code>field</code> is about to be accessed.
 6331         An event will be generated for each access of the field
 6332         until it is canceled with
 6333         <functionlink id="ClearFieldAccessWatch"></functionlink>.
 6334         Field accesses from Java programming language code or from JNI code are watched,
 6335         fields modified by other means are not watched.
 6336         Note that <jvmti/> users should be aware that their own field accesses
 6337         will trigger the watch.
 6338         A field can only have one field access watch set.
 6339         Modification of a field is not considered an access--use
 6340         <functionlink id="SetFieldModificationWatch"></functionlink>
 6341         to monitor modifications.
 6342       </description>
 6343       <origin>jvmdi</origin>
 6344       <capabilities>
 6345         <required id="can_generate_field_access_events"></required>
 6346       </capabilities>
 6347       <parameters>
 6348         <param id="klass">
 6349           <jclass field="field"/>
 6350             <description>
 6351               The class containing the field to watch
 6352             </description>
 6353         </param>
 6354         <param id="field">
 6355           <jfieldID class="klass"/>
 6356             <description>
 6357               The field to watch
 6358 
 6359             </description>
 6360         </param>
 6361       </parameters>
 6362       <errors>
 6363         <error id="JVMTI_ERROR_DUPLICATE">
 6364           The designated field is already being watched for accesses.
 6365         </error>
 6366       </errors>
 6367     </function>
 6368 
 6369     <function id="ClearFieldAccessWatch" num="42">
 6370       <synopsis>Clear Field Access Watch</synopsis>
 6371       <description>
 6372         Cancel a field access watch previously set by
 6373         <functionlink id="SetFieldAccessWatch"></functionlink>, on the
 6374         field specified
 6375         by <code>klass</code> and
 6376         <code>field</code>.
 6377       </description>
 6378       <origin>jvmdi</origin>
 6379       <capabilities>
 6380         <required id="can_generate_field_access_events"></required>
 6381       </capabilities>
 6382       <parameters>
 6383         <param id="klass">
 6384           <jclass field="field"/>
 6385             <description>
 6386               The class containing the field to watch
 6387             </description>
 6388         </param>
 6389         <param id="field">
 6390           <jfieldID class="klass"/>
 6391             <description>
 6392               The field to watch
 6393 
 6394             </description>
 6395         </param>
 6396       </parameters>
 6397       <errors>
 6398         <error id="JVMTI_ERROR_NOT_FOUND">
 6399           The designated field is not being watched for accesses.
 6400         </error>
 6401       </errors>
 6402     </function>
 6403 
 6404     <function id="SetFieldModificationWatch" num="43">
 6405       <synopsis>Set Field Modification Watch</synopsis>
 6406       <description>
 6407         Generate a <eventlink id="FieldModification"></eventlink> event
 6408         when the field specified
 6409         by <code>klass</code> and
 6410         <code>field</code> is about to be modified.
 6411         An event will be generated for each modification of the field
 6412         until it is canceled with
 6413         <functionlink id="ClearFieldModificationWatch"></functionlink>.
 6414         Field modifications from Java programming language code or from JNI code are watched,
 6415         fields modified by other means are not watched.
 6416         Note that <jvmti/> users should be aware that their own field modifications
 6417         will trigger the watch.
 6418         A field can only have one field modification watch set.
 6419       </description>
 6420       <origin>jvmdi</origin>
 6421       <capabilities>
 6422         <required id="can_generate_field_modification_events"></required>
 6423       </capabilities>
 6424       <parameters>
 6425         <param id="klass">
 6426           <jclass field="field"/>
 6427             <description>
 6428               The class containing the field to watch
 6429             </description>
 6430         </param>
 6431         <param id="field">
 6432           <jfieldID class="klass"/>
 6433             <description>
 6434               The field to watch
 6435 
 6436             </description>
 6437         </param>
 6438       </parameters>
 6439       <errors>
 6440         <error id="JVMTI_ERROR_DUPLICATE">
 6441           The designated field is already being watched for modifications.
 6442         </error>
 6443       </errors>
 6444     </function>
 6445 
 6446     <function id="ClearFieldModificationWatch" num="44">
 6447       <synopsis>Clear Field Modification Watch</synopsis>
 6448       <description>
 6449 
 6450         Cancel a field modification watch previously set by
 6451         <functionlink id="SetFieldModificationWatch"></functionlink>, on the
 6452         field specified
 6453         by <code>klass</code> and
 6454         <code>field</code>.
 6455       </description>
 6456       <origin>jvmdi</origin>
 6457       <capabilities>
 6458         <required id="can_generate_field_modification_events"></required>
 6459       </capabilities>
 6460       <parameters>
 6461         <param id="klass">
 6462           <jclass field="field"/>
 6463             <description>
 6464               The class containing the field to watch
 6465             </description>
 6466         </param>
 6467         <param id="field">
 6468           <jfieldID class="klass"/>
 6469             <description>
 6470               The field to watch
 6471 
 6472             </description>
 6473         </param>
 6474       </parameters>
 6475       <errors>
 6476         <error id="JVMTI_ERROR_NOT_FOUND">
 6477           The designated field is not being watched for modifications.
 6478         </error>
 6479       </errors>
 6480     </function>
 6481   </category>
 6482 
 6483   <category id="module" label="Module">
 6484 
 6485     <intro>
 6486     </intro>
 6487 
 6488     <function id="GetAllModules" num="3" since="9">
 6489       <synopsis>Get All Modules</synopsis>
 6490       <description>
 6491         Return an array of all modules loaded in the virtual machine.
 6492         The array includes the unnamed module for each class loader.
 6493         The number of modules in the array is returned via
 6494         <code>module_count_ptr</code>, and the array itself via
 6495         <code>modules_ptr</code>.
 6496         <p/>
 6497       </description>
 6498       <origin>new</origin>
 6499       <capabilities>
 6500       </capabilities>
 6501       <parameters>
 6502         <param id="module_count_ptr">
 6503           <outptr><jint/></outptr>
 6504           <description>
 6505             On return, points to the number of returned modules.
 6506           </description>
 6507         </param>
 6508         <param id="modules_ptr">
 6509           <allocbuf outcount="module_count_ptr"><jobject/></allocbuf>
 6510             <description>
 6511               On return, points to an array of references, one
 6512               for each module.
 6513             </description>
 6514         </param>
 6515       </parameters>
 6516       <errors>
 6517       </errors>
 6518     </function>
 6519 
 6520     <function id="GetNamedModule" num="40" since="9">
 6521       <synopsis>Get Named Module</synopsis>
 6522       <description>
 6523         Return the <code>java.lang.Module</code> object for a named
 6524         module defined to a class loader that contains a given package.
 6525         The module is returned via <code>module_ptr</code>.
 6526         <p/>
 6527         If a named module is defined to the class loader and it
 6528         contains the package then that named module is returned,
 6529         otherwise <code>NULL</code> is returned.
 6530         <p/>
 6531       </description>
 6532       <origin>new</origin>
 6533       <capabilities>
 6534       </capabilities>
 6535       <parameters>
 6536         <param id="class_loader">
 6537           <ptrtype>
 6538             <jobject/>
 6539             <nullok>the bootstrap loader is assumed</nullok>
 6540           </ptrtype>
 6541           <description>
 6542             A class loader.
 6543             If the <code>class_loader</code> is not <code>NULL</code>
 6544             or a subclass of <code>java.lang.ClassLoader</code>
 6545             this function returns
 6546             <errorlink id="JVMTI_ERROR_ILLEGAL_ARGUMENT"></errorlink>.
 6547           </description>
 6548         </param>
 6549         <param id="package_name">
 6550           <inbuf><char/></inbuf>
 6551           <description>
 6552             The name of the package, encoded as a
 6553             <internallink id="mUTF">modified UTF-8</internallink> string.
 6554             The package name is in internal form (JVMS 4.2.1);
 6555             identifiers are separated by forward slashes rather than periods.
 6556           </description>
 6557         </param>
 6558         <param id="module_ptr">
 6559           <outptr><jobject/></outptr>
 6560           <description>
 6561             On return, points to a <code>java.lang.Module</code> object
 6562             or points to <code>NULL</code>.
 6563           </description>
 6564         </param>
 6565       </parameters>
 6566       <errors>
 6567         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
 6568           If class loader is not <code>NULL</code> and is not a class loader object.
 6569         </error>
 6570       </errors>
 6571     </function>
 6572 
 6573     <function id="AddModuleReads" num="94" since="9">
 6574       <synopsis>Add Module Reads</synopsis>
 6575       <description>
 6576          Update a module to read another module. This function is a no-op
 6577          when <paramlink id="module"></paramlink> is an unnamed module.
 6578          This function facilitates the instrumentation of code
 6579          in named modules where that instrumentation requires
 6580          expanding the set of modules that a module reads.
 6581       </description>
 6582       <origin>new</origin>
 6583       <capabilities>
 6584       </capabilities>
 6585       <parameters>
 6586         <param id="module">
 6587           <ptrtype><jobject/></ptrtype>
 6588           <description>
 6589             The module to update.
 6590           </description>
 6591         </param>
 6592         <param id="to_module">
 6593           <ptrtype><jobject/></ptrtype>
 6594           <description>
 6595             The additional module to read.
 6596           </description>
 6597         </param>
 6598       </parameters>
 6599       <errors>
 6600         <error id="JVMTI_ERROR_INVALID_MODULE">
 6601           If <paramlink id="module"></paramlink> is not a module object.
 6602         </error>
 6603         <error id="JVMTI_ERROR_INVALID_MODULE">
 6604           If <paramlink id="to_module"></paramlink> is not a module object.
 6605         </error>
 6606         <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
 6607           if the module cannot be modified.
 6608           See <functionlink id="IsModifiableModule"/>.
 6609         </error>
 6610       </errors>
 6611     </function>
 6612 
 6613     <function id="AddModuleExports" num="95" since="9">
 6614       <synopsis>Add Module Exports</synopsis>
 6615       <description>
 6616          Update a module to export a package to another module.
 6617          This function is a no-op when <paramlink id="module"></paramlink>
 6618          is an unnamed module or an open module.
 6619          This function facilitates the instrumentation of code
 6620          in named modules where that instrumentation requires
 6621          expanding the set of packages that a module exports.
 6622       </description>
 6623       <origin>new</origin>
 6624       <capabilities>
 6625       </capabilities>
 6626       <parameters>
 6627         <param id="module">
 6628           <ptrtype><jobject/></ptrtype>
 6629           <description>
 6630             The module to update.
 6631           </description>
 6632         </param>
 6633         <param id="pkg_name">
 6634           <inbuf><char/></inbuf>
 6635           <description>
 6636             The exported package name.
 6637           </description>
 6638         </param>
 6639         <param id="to_module">
 6640           <ptrtype><jobject/></ptrtype>
 6641           <description>
 6642             The module the package is exported to.
 6643             If the <code>to_module</code> is not a subclass of
 6644             <code>java.lang.Module</code> this function returns
 6645             <errorlink id="JVMTI_ERROR_INVALID_MODULE"></errorlink>.
 6646           </description>
 6647         </param>
 6648       </parameters>
 6649       <errors>
 6650         <error id="JVMTI_ERROR_INVALID_MODULE">
 6651           If <paramlink id="module"></paramlink> is not a module object.
 6652         </error>
 6653         <error id="JVMTI_ERROR_INVALID_MODULE">
 6654           If <paramlink id="to_module"></paramlink> is not a module object.
 6655         </error>
 6656         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
 6657           If the package <paramlink id="pkg_name"></paramlink>
 6658           does not belong to the module.
 6659         </error>
 6660         <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
 6661           if the module cannot be modified.
 6662           See <functionlink id="IsModifiableModule"/>.
 6663         </error>
 6664       </errors>
 6665     </function>
 6666 
 6667     <function id="AddModuleOpens" num="96" since="9">
 6668       <synopsis>Add Module Opens</synopsis>
 6669       <description>
 6670          Update a module to open a package to another module.
 6671          This function is a no-op when <paramlink id="module"></paramlink>
 6672          is an unnamed module or an open module.
 6673          This function facilitates the instrumentation of code
 6674          in modules where that instrumentation requires
 6675          expanding the set of packages that a module opens to
 6676          other modules.
 6677       </description>
 6678       <origin>new</origin>
 6679       <capabilities>
 6680       </capabilities>
 6681       <parameters>
 6682         <param id="module">
 6683           <ptrtype><jobject/></ptrtype>
 6684           <description>
 6685             The module to update.
 6686           </description>
 6687         </param>
 6688         <param id="pkg_name">
 6689           <inbuf><char/></inbuf>
 6690           <description>
 6691             The package name of the package to open.
 6692           </description>
 6693         </param>
 6694         <param id="to_module">
 6695           <ptrtype><jobject/></ptrtype>
 6696           <description>
 6697             The module with the package to open.
 6698             If the <code>to_module</code> is not a subclass of
 6699             <code>java.lang.Module</code> this function returns
 6700             <errorlink id="JVMTI_ERROR_INVALID_MODULE"></errorlink>.
 6701           </description>
 6702         </param>
 6703       </parameters>
 6704       <errors>
 6705         <error id="JVMTI_ERROR_INVALID_MODULE">
 6706           If <paramlink id="module"></paramlink> is not a module object.
 6707         </error>
 6708         <error id="JVMTI_ERROR_INVALID_MODULE">
 6709           If <paramlink id="to_module"></paramlink> is not a module object.
 6710         </error>
 6711         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
 6712           If the package <paramlink id="pkg_name"></paramlink>
 6713           does not belong to the module.
 6714         </error>
 6715         <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
 6716           if the module cannot be modified.
 6717           See <functionlink id="IsModifiableModule"/>.
 6718         </error>
 6719       </errors>
 6720     </function>
 6721 
 6722     <function id="AddModuleUses" num="97" since="9">
 6723       <synopsis>Add Module Uses</synopsis>
 6724       <description>
 6725          Updates a module to add a service to the set of services that
 6726          a module uses. This function is a no-op when the module
 6727          is an unnamed module.
 6728          This function facilitates the instrumentation of code
 6729          in named modules where that instrumentation requires
 6730          expanding the set of services that a module is using.
 6731       </description>
 6732       <origin>new</origin>
 6733       <capabilities>
 6734       </capabilities>
 6735       <parameters>
 6736         <param id="module">
 6737           <ptrtype><jobject/></ptrtype>
 6738           <description>
 6739             The module to update.
 6740           </description>
 6741         </param>
 6742         <param id="service">
 6743           <ptrtype><jclass/></ptrtype>
 6744           <description>
 6745             The service to use.
 6746           </description>
 6747         </param>
 6748       </parameters>
 6749       <errors>
 6750         <error id="JVMTI_ERROR_INVALID_MODULE">
 6751           If <paramlink id="module"></paramlink> is not a module object.
 6752         </error>
 6753         <error id="JVMTI_ERROR_INVALID_CLASS">
 6754           If <paramlink id="service"></paramlink> is not a class object.
 6755         </error>
 6756         <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
 6757           if the module cannot be modified.
 6758           See <functionlink id="IsModifiableModule"/>.
 6759         </error>
 6760       </errors>
 6761     </function>
 6762 
 6763     <function id="AddModuleProvides" num="98" since="9">
 6764       <synopsis>Add Module Provides</synopsis>
 6765       <description>
 6766          Updates a module to add a service to the set of services that
 6767          a module provides. This function is a no-op when the module
 6768          is an unnamed module.
 6769          This function facilitates the instrumentation of code
 6770          in named modules where that instrumentation requires
 6771          changes to the services that are provided.
 6772       </description>
 6773       <origin>new</origin>
 6774       <capabilities>
 6775       </capabilities>
 6776       <parameters>
 6777         <param id="module">
 6778           <ptrtype><jobject/></ptrtype>
 6779           <description>
 6780             The module to update.
 6781           </description>
 6782         </param>
 6783         <param id="service">
 6784           <ptrtype><jclass/></ptrtype>
 6785           <description>
 6786             The service to provide.
 6787           </description>
 6788         </param>
 6789         <param id="impl_class">
 6790           <ptrtype><jclass/></ptrtype>
 6791           <description>
 6792             The implementation class for the provided service.
 6793           </description>
 6794         </param>
 6795       </parameters>
 6796       <errors>
 6797         <error id="JVMTI_ERROR_INVALID_MODULE">
 6798           If <paramlink id="module"></paramlink> is not a module object.
 6799         </error>
 6800         <error id="JVMTI_ERROR_INVALID_CLASS">
 6801           If <paramlink id="service"></paramlink> is not a class object.
 6802         </error>
 6803         <error id="JVMTI_ERROR_INVALID_CLASS">
 6804           If <paramlink id="impl_class"></paramlink> is not a class object.
 6805         </error>
 6806         <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
 6807           if the module cannot be modified.
 6808           See <functionlink id="IsModifiableModule"/>.
 6809         </error>
 6810       </errors>
 6811     </function>
 6812 
 6813     <function id="IsModifiableModule" num="99" since="9">
 6814       <synopsis>Is Modifiable Module</synopsis>
 6815       <description>
 6816         Determines whether a module is modifiable.
 6817         If a module is modifiable then this module can be updated with
 6818         <functionlink id="AddModuleReads"/>, <functionlink id="AddModuleExports"/>,
 6819         <functionlink id="AddModuleOpens"/>, <functionlink id="AddModuleUses"/>,
 6820         and <functionlink id="AddModuleProvides"/>. If a module is not modifiable
 6821         then the module can not be updated with these functions. The result of
 6822         this function is always <code>JNI_TRUE</code> when called to determine
 6823         if an unnamed module is modifiable.
 6824       </description>
 6825       <origin>new</origin>
 6826       <capabilities>
 6827       </capabilities>
 6828       <parameters>
 6829         <param id="module">
 6830           <ptrtype><jobject/></ptrtype>
 6831           <description>
 6832             The module to query.
 6833           </description>
 6834         </param>
 6835         <param id="is_modifiable_module_ptr">
 6836           <outptr><jboolean/></outptr>
 6837           <description>
 6838             On return, points to the boolean result of this function.
 6839           </description>
 6840         </param>
 6841       </parameters>
 6842       <errors>
 6843         <error id="JVMTI_ERROR_INVALID_MODULE">
 6844           If <paramlink id="module"></paramlink> is not a module object.
 6845         </error>
 6846       </errors>
 6847     </function>
 6848 
 6849   </category>
 6850 
 6851   <category id="class" label="Class">
 6852     <function id="GetLoadedClasses" jkernel="yes" num="78">
 6853       <synopsis>Get Loaded Classes</synopsis>
 6854       <description>
 6855         Return an array of all classes loaded in the virtual machine.
 6856         The number of classes in the array is returned via
 6857         <code>class_count_ptr</code>, and the array itself via
 6858         <code>classes_ptr</code>.
 6859         <p/>
 6860         A class or interface creation can be triggered by one of the following:
 6861         <ul>
 6862         <li>By loading and deriving a class from a <code>class</code> file representation
 6863             using a class loader (see <vmspec chapter="5.3"/>).</li>
 6864         <li>By invoking <externallink id="../api/java.base/java/lang/invoke/MethodHandles.Lookup.html#defineHiddenClass(byte[],boolean,java.lang.invoke.MethodHandles.Lookup.ClassOption...)">Lookup::defineHiddenClass</externallink>
 6865             that creates a hidden class or interface from a <code>class</code> file representation.</li>
 6866         <li>By invoking methods in certain Java SE Platform APIs such as reflection.</li>
 6867          </ul>
 6868         <p/>
 6869         An array class is created directly by the Java virtual machine.  The creation
 6870         can be triggered by using class loaders or by invoking methods in certain
 6871         Java SE Platform APIs such as reflection.
 6872         <p/>
 6873         The returned list includes all classes and interfaces, including
 6874         <externallink id="../api/java.base/java/lang/Class.html#isHidden()">
 6875         hidden classes or interfaces</externallink>,
 6876         and also array classes of all types
 6877         (including arrays of primitive types).
 6878         Primitive classes (for example, <code>java.lang.Integer.TYPE</code>) are
 6879         <i>not</i> included in the returned list.
 6880       </description>
 6881       <origin>jvmdi</origin>
 6882       <capabilities>
 6883       </capabilities>
 6884       <parameters>
 6885         <param id="class_count_ptr">
 6886           <outptr><jint/></outptr>
 6887           <description>
 6888             On return, points to the number of classes.
 6889           </description>
 6890         </param>
 6891         <param id="classes_ptr">
 6892           <allocbuf outcount="class_count_ptr"><jclass/></allocbuf>
 6893             <description>
 6894               On return, points to an array of references, one
 6895               for each class.
 6896             </description>
 6897         </param>
 6898       </parameters>
 6899       <errors>
 6900       </errors>
 6901     </function>
 6902 
 6903     <function id="GetClassLoaderClasses" jkernel="yes" num="79">
 6904       <synopsis>Get Classloader Classes</synopsis>
 6905       <description>
 6906         Returns an array of all classes which this class loader
 6907         can find by name via
 6908         <externallink id="../api/java.base/java/lang/ClassLoader.html#loadClass(java.lang.String,boolean)">ClassLoader::loadClass</externallink>,
 6909         <externallink id="../api/java.base/java/lang/Class.html#forName(java.lang.String,boolean,java.lang.ClassLoader)">Class::forName</externallink> and bytecode linkage.
 6910         That is, all classes for which <code>initiating_loader</code>
 6911         has been recorded as an initiating loader.
 6912         Each class in the returned array was created by this class loader,
 6913         either by defining it directly or by delegation to another class loader.
 6914         See <vmspec chapter="5.3"/>.
 6915         <p/>
 6916         The returned list does not include
 6917         <externallink id="../api/java.base/java/lang/Class.html#isHidden()">hidden
 6918         classes or interfaces</externallink> or array classes whose
 6919         element type is a hidden class or interface as they cannot be discovered
 6920         by any class loader.
 6921         <p/>
 6922         The number of classes in the array is returned via
 6923         <code>class_count_ptr</code>, and the array itself via
 6924         <code>classes_ptr</code>.
 6925         <p/>
 6926         See <externallink id="../api/java.base/java/lang/invoke/MethodHandles.Lookup.html#defineHiddenClass(byte[],boolean,java.lang.invoke.MethodHandles.Lookup.ClassOption...)">Lookup::defineHiddenClass</externallink>.
 6927       </description>
 6928       <origin>jvmdi</origin>
 6929       <capabilities>
 6930       </capabilities>
 6931       <parameters>
 6932         <param id="initiating_loader">
 6933           <ptrtype>
 6934             <jobject/>
 6935             <nullok>the classes initiated by the bootstrap loader will be returned</nullok>
 6936           </ptrtype>
 6937             <description>
 6938               An initiating class loader.
 6939             </description>
 6940         </param>
 6941         <param id="class_count_ptr">
 6942           <outptr><jint/></outptr>
 6943           <description>
 6944             On return, points to the number of classes.
 6945           </description>
 6946         </param>
 6947         <param id="classes_ptr">
 6948           <allocbuf outcount="class_count_ptr"><jclass/></allocbuf>
 6949             <description>
 6950               On return, points to an array of references, one
 6951               for each class.
 6952             </description>
 6953         </param>
 6954       </parameters>
 6955       <errors>
 6956       </errors>
 6957     </function>
 6958 
 6959     <function id="GetClassSignature" phase="start" num="48">
 6960       <synopsis>Get Class Signature</synopsis>
 6961       <description>
 6962         Return the name and the generic signature of the class indicated by <code>klass</code>.
 6963         <p/>
 6964         If the class is a class or interface, then:
 6965         <ul>
 6966         <li>If the class or interface is not <externallink id="../api/java.base/java/lang/Class.html#isHidden()">hidden</externallink>,
 6967           then the returned name is the <externallink id="jni/types.html#type-signatures">
 6968           JNI type signature</externallink>.
 6969           For example, java.util.List is "Ljava/util/List;"
 6970         </li>
 6971         <li>If the class or interface is <externallink id="../api/java.base/java/lang/Class.html#isHidden()">hidden</externallink>,
 6972           then the returned name is a string of the form:
 6973           <code>"L" + N + "." +  S + ";"</code>
 6974           where <code>N</code> is the binary name encoded in internal form (JVMS 4.2.1)
 6975           indicated by the <code>class</code> file passed to
 6976           <externallink id="../api/java.base/java/lang/invoke/MethodHandles.Lookup.html#defineHiddenClass(byte[],boolean,java.lang.invoke.MethodHandles.Lookup.ClassOption...)">Lookup::defineHiddenClass</externallink>,
 6977           and <code>S</code> is an unqualified name.
 6978           The returned name is not a type descriptor and does not conform to JVMS 4.3.2.
 6979           For example, com.foo.Foo/AnySuffix is "Lcom/foo/Foo.AnySuffix;"
 6980         </li>
 6981         </ul>
 6982         <p/>
 6983         If the class indicated by <code>klass</code> represents an array class, then
 6984         the returned name is a string consisting of one or more "<code>[</code>" characters
 6985         representing the depth of the array nesting, followed by the class signature
 6986         of the element type.  For example the class signature of java.lang.String[] is
 6987         "[Ljava/lang/String;" and that of int[] is "[I".
 6988         <p/>
 6989         If the class indicated by <code>klass</code> represents primitive type or <code>void</code>,
 6990         then the returned name is the <externallink id="jni/types.html#type-signatures">
 6991         type signature character of the corresponding primitive type</externallink>.
 6992         For example, java.lang.Integer.TYPE is "I".
 6993       </description>
 6994       <origin>jvmdiClone</origin>
 6995       <capabilities>
 6996       </capabilities>
 6997       <parameters>
 6998         <param id="klass">
 6999           <jclass/>
 7000             <description>
 7001               The class to query.
 7002             </description>
 7003         </param>
 7004         <param id="signature_ptr">
 7005           <allocbuf>
 7006             <char/>
 7007             <nullok>the signature is not returned</nullok>
 7008           </allocbuf>
 7009           <description>
 7010             On return, points to the JNI type signature of the class, encoded as a
 7011             <internallink id="mUTF">modified UTF-8</internallink> string.
 7012           </description>
 7013         </param>
 7014         <param id="generic_ptr">
 7015           <allocbuf>
 7016             <char/>
 7017             <nullok>the generic signature is not returned</nullok>
 7018           </allocbuf>
 7019           <description>
 7020             On return, points to the generic signature of the class, encoded as a
 7021             <internallink id="mUTF">modified UTF-8</internallink> string.
 7022             If there is no generic signature attribute for the class, then,
 7023             on return, points to <code>NULL</code>.
 7024           </description>
 7025         </param>
 7026       </parameters>
 7027       <errors>
 7028       </errors>
 7029     </function>
 7030 
 7031     <function id="GetClassStatus" phase="start" num="49">
 7032       <synopsis>Get Class Status</synopsis>
 7033       <description>
 7034         Get the status of the class. Zero or more of the following bits can be
 7035         set.
 7036         <constants id="jvmtiClassStatus" label="Class Status Flags" kind="bits">
 7037           <constant id="JVMTI_CLASS_STATUS_VERIFIED" num="1">
 7038             Class bytecodes have been verified
 7039           </constant>
 7040           <constant id="JVMTI_CLASS_STATUS_PREPARED" num="2">
 7041             Class preparation is complete
 7042           </constant>
 7043           <constant id="JVMTI_CLASS_STATUS_INITIALIZED" num="4">
 7044             Class initialization is complete. Static initializer has been run.
 7045           </constant>
 7046           <constant id="JVMTI_CLASS_STATUS_ERROR" num="8">
 7047             Error during initialization makes class unusable
 7048           </constant>
 7049           <constant id="JVMTI_CLASS_STATUS_ARRAY" num="16">
 7050             Class is an array.  If set, all other bits are zero.
 7051           </constant>
 7052           <constant id="JVMTI_CLASS_STATUS_PRIMITIVE" num="32">
 7053             Class is a primitive class (for example, <code>java.lang.Integer.TYPE</code>).
 7054             If set, all other bits are zero.
 7055           </constant>
 7056         </constants>
 7057       </description>
 7058       <origin>jvmdi</origin>
 7059       <capabilities>
 7060       </capabilities>
 7061       <parameters>
 7062         <param id="klass">
 7063           <jclass/>
 7064             <description>
 7065               The class to query.
 7066             </description>
 7067         </param>
 7068         <param id="status_ptr">
 7069           <outptr><jint/></outptr>
 7070           <description>
 7071             On return, points to the current state of this class as one or
 7072             more of the <internallink id="jvmtiClassStatus">class status flags</internallink>.
 7073           </description>
 7074         </param>
 7075       </parameters>
 7076       <errors>
 7077       </errors>
 7078     </function>
 7079 
 7080     <function id="GetSourceFileName" phase="start" num="50">
 7081       <synopsis>Get Source File Name</synopsis>
 7082       <description>
 7083         For the class indicated by <code>klass</code>, return the source file
 7084         name via <code>source_name_ptr</code>. The returned string
 7085         is a file name only and never contains a directory name.
 7086         <p/>
 7087         For primitive classes (for example, <code>java.lang.Integer.TYPE</code>)
 7088         and for arrays this function returns
 7089         <errorlink id="JVMTI_ERROR_ABSENT_INFORMATION"></errorlink>.
 7090       </description>
 7091       <origin>jvmdi</origin>
 7092       <capabilities>
 7093         <required id="can_get_source_file_name"></required>
 7094       </capabilities>
 7095       <parameters>
 7096         <param id="klass">
 7097           <jclass/>
 7098             <description>
 7099               The class to query.
 7100             </description>
 7101         </param>
 7102         <param id="source_name_ptr">
 7103           <allocbuf><char/></allocbuf>
 7104           <description>
 7105             On return, points to the class's source file name, encoded as a
 7106             <internallink id="mUTF">modified UTF-8</internallink> string.
 7107           </description>
 7108         </param>
 7109       </parameters>
 7110       <errors>
 7111         <error id="JVMTI_ERROR_ABSENT_INFORMATION">
 7112           Class information does not include a source file name. This includes
 7113           cases where the class is an array class or primitive class.
 7114         </error>
 7115       </errors>
 7116     </function>
 7117 
 7118     <function id="GetClassModifiers" phase="start" num="51">
 7119       <synopsis>Get Class Modifiers</synopsis>
 7120       <description>
 7121         For the class indicated by <code>klass</code>, return the access
 7122         flags
 7123         via <code>modifiers_ptr</code>.
 7124         Access flags are defined in <vmspec chapter="4"/>.
 7125         <p/>
 7126         If the class is an array class, then its public, private, and protected
 7127         modifiers are the same as those of its component type. For arrays of
 7128         primitives, this component type is represented by one of the primitive
 7129         classes (for example, <code>java.lang.Integer.TYPE</code>).
 7130         <p/>
 7131         If the class is a primitive class, its public modifier is always true,
 7132         and its protected and private modifiers are always false.
 7133         <p/>
 7134         If the class is an array class or a primitive class then its final
 7135         modifier is always true and its interface modifier is always false.
 7136         The values of its other modifiers are not determined by this specification.
 7137 
 7138       </description>
 7139       <origin>jvmdi</origin>
 7140       <capabilities>
 7141       </capabilities>
 7142       <parameters>
 7143         <param id="klass">
 7144           <jclass/>
 7145             <description>
 7146               The class to query.
 7147             </description>
 7148         </param>
 7149         <param id="modifiers_ptr">
 7150           <outptr><jint/></outptr>
 7151           <description>
 7152             On return, points to the current access flags of this class.
 7153 
 7154           </description>
 7155         </param>
 7156       </parameters>
 7157       <errors>
 7158       </errors>
 7159     </function>
 7160 
 7161     <function id="GetClassMethods" phase="start" num="52">
 7162       <synopsis>Get Class Methods</synopsis>
 7163       <description>
 7164         For the class indicated by <code>klass</code>, return a count of
 7165         methods via <code>method_count_ptr</code> and a list of
 7166         method IDs via <code>methods_ptr</code>. The method list contains
 7167         constructors and static initializers as well as true methods.
 7168         Only directly declared methods are returned (not inherited methods).
 7169         An empty method list is returned for array classes and primitive classes
 7170         (for example, <code>java.lang.Integer.TYPE</code>).
 7171       </description>
 7172       <origin>jvmdi</origin>
 7173       <capabilities>
 7174         <capability id="can_maintain_original_method_order"/>
 7175       </capabilities>
 7176       <parameters>
 7177         <param id="klass">
 7178           <jclass/>
 7179             <description>
 7180               The class to query.
 7181             </description>
 7182         </param>
 7183         <param id="method_count_ptr">
 7184           <outptr><jint/></outptr>
 7185           <description>
 7186             On return, points to the number of methods declared in this class.
 7187           </description>
 7188         </param>
 7189         <param id="methods_ptr">
 7190           <allocbuf outcount="method_count_ptr"><jmethodID class="klass"/></allocbuf>
 7191             <description>
 7192               On return, points to the method ID array.
 7193             </description>
 7194         </param>
 7195       </parameters>
 7196       <errors>
 7197         <error id="JVMTI_ERROR_CLASS_NOT_PREPARED">
 7198           <paramlink id="klass"></paramlink> is not prepared.
 7199         </error>
 7200       </errors>
 7201     </function>
 7202 
 7203     <function id="GetClassFields" phase="start" num="53">
 7204       <synopsis>Get Class Fields</synopsis>
 7205       <description>
 7206         For the class indicated by <code>klass</code>, return a count of fields
 7207         via <code>field_count_ptr</code> and a list of field IDs via
 7208         <code>fields_ptr</code>.
 7209         Only directly declared fields are returned (not inherited fields).
 7210         Fields are returned in the order they occur in the class file.
 7211         An empty field list is returned for array classes and primitive classes
 7212         (for example, <code>java.lang.Integer.TYPE</code>).
 7213         Use JNI to determine the length of an array.
 7214       </description>
 7215       <origin>jvmdi</origin>
 7216       <capabilities>
 7217       </capabilities>
 7218       <parameters>
 7219         <param id="klass">
 7220           <jclass/>
 7221             <description>
 7222               The class to query.
 7223             </description>
 7224         </param>
 7225         <param id="field_count_ptr">
 7226           <outptr><jint/></outptr>
 7227           <description>
 7228             On return, points to the number of fields declared in this class.
 7229           </description>
 7230         </param>
 7231         <param id="fields_ptr">
 7232           <allocbuf outcount="field_count_ptr"><jfieldID/></allocbuf>
 7233             <description>
 7234               On return, points to the field ID array.
 7235             </description>
 7236         </param>
 7237       </parameters>
 7238       <errors>
 7239         <error id="JVMTI_ERROR_CLASS_NOT_PREPARED">
 7240           <paramlink id="klass"></paramlink> is not prepared.
 7241         </error>
 7242       </errors>
 7243     </function>
 7244 
 7245     <function id="GetImplementedInterfaces" phase="start" num="54">
 7246       <synopsis>Get Implemented Interfaces</synopsis>
 7247       <description>
 7248         Return the direct super-interfaces of this class. For a class, this
 7249         function returns the interfaces declared in its <code>implements</code>
 7250         clause. For an interface, this function returns the interfaces declared in
 7251         its <code>extends</code> clause.
 7252         An empty interface list is returned for array classes and primitive classes
 7253         (for example, <code>java.lang.Integer.TYPE</code>).
 7254       </description>
 7255       <origin>jvmdi</origin>
 7256       <capabilities>
 7257       </capabilities>
 7258       <parameters>
 7259         <param id="klass">
 7260           <jclass/>
 7261             <description>
 7262               The class to query.
 7263             </description>
 7264         </param>
 7265         <param id="interface_count_ptr">
 7266           <outptr><jint/></outptr>
 7267           <description>
 7268             On return, points to the number of interfaces.
 7269           </description>
 7270         </param>
 7271         <param id="interfaces_ptr">
 7272           <allocbuf outcount="interface_count_ptr"><jclass/></allocbuf>
 7273             <description>
 7274               On return, points to the interface array.
 7275             </description>
 7276         </param>
 7277       </parameters>
 7278       <errors>
 7279         <error id="JVMTI_ERROR_CLASS_NOT_PREPARED">
 7280           <paramlink id="klass"></paramlink> is not prepared.
 7281         </error>
 7282       </errors>
 7283     </function>
 7284 
 7285     <function id="GetClassVersionNumbers" phase="start" num="145" since="1.1">
 7286       <synopsis>Get Class Version Numbers</synopsis>
 7287       <description>
 7288         For the class indicated by <code>klass</code>,
 7289         return the minor and major version numbers,
 7290         as defined in
 7291         <vmspec chapter="4"/>.
 7292       </description>
 7293       <origin>new</origin>
 7294       <capabilities>
 7295       </capabilities>
 7296       <parameters>
 7297         <param id="klass">
 7298           <jclass/>
 7299             <description>
 7300               The class to query.
 7301             </description>
 7302         </param>
 7303         <param id="minor_version_ptr">
 7304           <outptr><jint/></outptr>
 7305           <description>
 7306             On return, points to the value of the
 7307             <code>minor_version</code> item of the
 7308             Class File Format.
 7309             Note: to be consistent with the Class File Format,
 7310             the minor version number is the first parameter.
 7311           </description>
 7312         </param>
 7313         <param id="major_version_ptr">
 7314           <outptr><jint/></outptr>
 7315           <description>
 7316             On return, points to the value of the
 7317             <code>major_version</code> item of the
 7318             Class File Format.
 7319           </description>
 7320         </param>
 7321       </parameters>
 7322       <errors>
 7323         <error id="JVMTI_ERROR_ABSENT_INFORMATION">
 7324           The class is a primitive or array class.
 7325         </error>
 7326       </errors>
 7327     </function>
 7328 
 7329     <function id="GetConstantPool" phase="start" num="146" since="1.1">
 7330       <synopsis>Get Constant Pool</synopsis>
 7331       <description>
 7332         For the class indicated by <code>klass</code>,
 7333         return the raw bytes of the constant pool in the format of the
 7334         <code>constant_pool</code> item of
 7335         <vmspec chapter="4"/>.
 7336         The format of the constant pool may differ between versions
 7337         of the Class File Format, so, the
 7338         <functionlink id="GetClassVersionNumbers">minor and major
 7339         class version numbers</functionlink> should be checked for
 7340         compatibility.
 7341         <p/>
 7342         The returned constant pool might not have the same layout or
 7343         contents as the constant pool in the defining class file.
 7344         The constant pool returned by GetConstantPool() may have
 7345         more or fewer entries than the defining constant pool.
 7346         Entries may be in a different order.
 7347         The constant pool returned by GetConstantPool() will match the
 7348         constant pool used by
 7349         <functionlink id="GetBytecodes">GetBytecodes()</functionlink>.
 7350         That is, the bytecodes returned by GetBytecodes() will have
 7351         constant pool indices which refer to constant pool entries returned
 7352         by GetConstantPool().
 7353         Note that since <functionlink id="RetransformClasses"/>
 7354         and <functionlink id="RedefineClasses"/> can change
 7355         the constant pool, the constant pool returned by this function
 7356         can change accordingly.  Thus, the correspondence between
 7357         GetConstantPool() and GetBytecodes() does not hold if there
 7358         is an intervening class retransformation or redefinition.
 7359         The value of a constant pool entry used by a given bytecode will
 7360         match that of the defining class file (even if the indices don't match).
 7361         Constant pool entries which are not used directly or indirectly by
 7362         bytecodes (for example,  UTF-8 strings associated with annotations) are
 7363         not  required to exist in the returned constant pool.
 7364       </description>
 7365       <origin>new</origin>
 7366       <capabilities>
 7367         <required id="can_get_constant_pool"></required>
 7368       </capabilities>
 7369       <parameters>
 7370         <param id="klass">
 7371           <jclass/>
 7372             <description>
 7373               The class to query.
 7374             </description>
 7375         </param>
 7376         <param id="constant_pool_count_ptr">
 7377           <outptr><jint/></outptr>
 7378           <description>
 7379             On return, points to the number of entries
 7380             in the constant pool table plus one.
 7381             This corresponds to the <code>constant_pool_count</code>
 7382             item of the Class File Format.
 7383           </description>
 7384         </param>
 7385         <param id="constant_pool_byte_count_ptr">
 7386           <outptr><jint/></outptr>
 7387           <description>
 7388             On return, points to the number of bytes
 7389             in the returned raw constant pool.
 7390           </description>
 7391         </param>
 7392         <param id="constant_pool_bytes_ptr">
 7393           <allocbuf outcount="constant_pool_byte_count_ptr"><uchar/></allocbuf>
 7394             <description>
 7395               On return, points to the raw constant pool, that is the bytes
 7396               defined by the <code>constant_pool</code> item of the
 7397               Class File Format
 7398             </description>
 7399         </param>
 7400       </parameters>
 7401       <errors>
 7402         <error id="JVMTI_ERROR_ABSENT_INFORMATION">
 7403           The class is a primitive or array class.
 7404         </error>
 7405       </errors>
 7406     </function>
 7407 
 7408     <function id="IsInterface" phase="start" num="55">
 7409       <synopsis>Is Interface</synopsis>
 7410       <description>
 7411         Determines whether a class object reference represents an interface.
 7412         The <code>jboolean</code> result is
 7413         <code>JNI_TRUE</code> if the "class" is actually an interface,
 7414         <code>JNI_FALSE</code> otherwise.
 7415       </description>
 7416       <origin>jvmdi</origin>
 7417       <capabilities>
 7418       </capabilities>
 7419       <parameters>
 7420         <param id="klass">
 7421           <jclass/>
 7422             <description>
 7423               The class to query.
 7424             </description>
 7425         </param>
 7426         <param id="is_interface_ptr">
 7427           <outptr><jboolean/></outptr>
 7428           <description>
 7429             On return, points to the boolean result of this function.
 7430 
 7431           </description>
 7432         </param>
 7433       </parameters>
 7434       <errors>
 7435       </errors>
 7436     </function>
 7437 
 7438     <function id="IsArrayClass" phase="start" num="56">
 7439       <synopsis>Is Array Class</synopsis>
 7440       <description>
 7441         Determines whether a class object reference represents an array.
 7442         The <code>jboolean</code> result is
 7443         <code>JNI_TRUE</code> if the class is an array,
 7444         <code>JNI_FALSE</code> otherwise.
 7445       </description>
 7446       <origin>jvmdi</origin>
 7447       <capabilities>
 7448       </capabilities>
 7449       <parameters>
 7450         <param id="klass">
 7451           <jclass/>
 7452             <description>
 7453               The class to query.
 7454             </description>
 7455         </param>
 7456         <param id="is_array_class_ptr">
 7457           <outptr><jboolean/></outptr>
 7458           <description>
 7459             On return, points to the boolean result of this function.
 7460 
 7461           </description>
 7462         </param>
 7463       </parameters>
 7464       <errors>
 7465       </errors>
 7466     </function>
 7467 
 7468     <function id="IsModifiableClass" jkernel="yes" phase="start" num="45" since="1.1">
 7469       <synopsis>Is Modifiable Class</synopsis>
 7470       <description>
 7471         Determines whether a class is modifiable.
 7472         If a class is modifiable (<paramlink id="is_modifiable_class_ptr"/>
 7473         returns <code>JNI_TRUE</code>) the class can be
 7474         redefined with <functionlink id="RedefineClasses"/> (assuming
 7475         the agent possesses the
 7476         <fieldlink id="can_redefine_classes" struct="jvmtiCapabilities"/>
 7477         capability) or
 7478         retransformed with <functionlink id="RetransformClasses"/> (assuming
 7479         the agent possesses the
 7480         <fieldlink id="can_retransform_classes" struct="jvmtiCapabilities"/>
 7481         capability).
 7482         If a class is not modifiable (<paramlink id="is_modifiable_class_ptr"/>
 7483         returns <code>JNI_FALSE</code>) the class can be neither
 7484         redefined nor retransformed.
 7485         <p/>
 7486         Primitive classes (for example, <code>java.lang.Integer.TYPE</code>),
 7487         array classes, and some implementation defined classes are never modifiable.
 7488         <p/>
 7489       </description>
 7490       <origin>new</origin>
 7491       <capabilities>
 7492         <capability id="can_redefine_any_class">
 7493           If possessed then all classes (except primitive, array, and some implementation defined
 7494           classes) are modifiable with <functionlink id="RedefineClasses"/>.
 7495         </capability>
 7496         <capability id="can_retransform_any_class">
 7497           If possessed then all classes (except primitive, array, and some implementation defined
 7498           classes) are modifiable with <functionlink id="RetransformClasses"/>.
 7499         </capability>
 7500         <capability id="can_redefine_classes">
 7501           No effect on the result of the function.
 7502           But must additionally be possessed to modify the class with
 7503           <functionlink id="RedefineClasses"/>.
 7504         </capability>
 7505         <capability id="can_retransform_classes">
 7506           No effect on the result of the function.
 7507           But must additionally be possessed to modify the class with
 7508           <functionlink id="RetransformClasses"/>.
 7509         </capability>
 7510       </capabilities>
 7511       <parameters>
 7512         <param id="klass">
 7513           <jclass/>
 7514             <description>
 7515               The class to query.
 7516             </description>
 7517         </param>
 7518         <param id="is_modifiable_class_ptr">
 7519           <outptr><jboolean/></outptr>
 7520           <description>
 7521             On return, points to the boolean result of this function.
 7522           </description>
 7523         </param>
 7524       </parameters>
 7525       <errors>
 7526       </errors>
 7527     </function>
 7528 
 7529     <function id="GetClassLoader" phase="start" num="57">
 7530       <synopsis>Get Class Loader</synopsis>
 7531       <description>
 7532         For the class indicated by <code>klass</code>, return via
 7533         <code>classloader_ptr</code> a reference to the class loader for the
 7534         class.
 7535       </description>
 7536       <origin>jvmdi</origin>
 7537       <capabilities>
 7538       </capabilities>
 7539       <parameters>
 7540         <param id="klass">
 7541           <jclass/>
 7542             <description>
 7543               The class to query.
 7544             </description>
 7545         </param>
 7546         <param id="classloader_ptr">
 7547           <outptr><jobject/></outptr>
 7548             <description>
 7549               On return, points to the class loader that loaded
 7550               this class.
 7551               If the class was not created by a class loader
 7552               or if the class loader is the bootstrap class loader,
 7553               points to <code>NULL</code>.
 7554             </description>
 7555         </param>
 7556       </parameters>
 7557       <errors>
 7558       </errors>
 7559 
 7560     </function>
 7561 
 7562     <function id="GetSourceDebugExtension" phase="start" num="90">
 7563       <synopsis>Get Source Debug Extension</synopsis>
 7564       <description>
 7565         For the class indicated by <code>klass</code>, return the debug
 7566         extension via <code>source_debug_extension_ptr</code>.
 7567         The returned string
 7568         contains exactly the debug extension information present in the
 7569         class file of <code>klass</code>.
 7570       </description>
 7571       <origin>jvmdi</origin>
 7572       <capabilities>
 7573         <required id="can_get_source_debug_extension"></required>
 7574       </capabilities>
 7575       <parameters>
 7576         <param id="klass">
 7577           <jclass/>
 7578             <description>
 7579               The class to query.
 7580             </description>
 7581         </param>
 7582         <param id="source_debug_extension_ptr">
 7583           <allocbuf><char/></allocbuf>
 7584           <description>
 7585             On return, points to the class's debug extension, encoded as a
 7586             <internallink id="mUTF">modified UTF-8</internallink> string.
 7587           </description>
 7588         </param>
 7589       </parameters>
 7590       <errors>
 7591         <error id="JVMTI_ERROR_ABSENT_INFORMATION">
 7592           Class information does not include a debug extension.
 7593         </error>
 7594       </errors>
 7595     </function>
 7596 
 7597     <function id="RetransformClasses" jkernel="yes" num="152" since="1.1">
 7598       <synopsis>Retransform Classes</synopsis>
 7599       <description>
 7600         This function facilitates the
 7601         <internallink id="bci">bytecode instrumentation</internallink>
 7602         of already loaded classes.
 7603         To replace the class definition without reference to the existing
 7604         bytecodes, as one might do when recompiling from source for
 7605         fix-and-continue debugging, <functionlink id="RedefineClasses"/>
 7606         function should be used instead.
 7607         <p/>
 7608         When classes are initially loaded or when they are
 7609         <functionlink id="RedefineClasses">redefined</functionlink>,
 7610         the initial class file bytes can be transformed with the
 7611         <eventlink id="ClassFileLoadHook"/> event.
 7612         This function reruns the transformation process
 7613         (whether or not a transformation has previously occurred).
 7614         This retransformation follows these steps:
 7615         <ul>
 7616           <li>starting from the initial class file bytes
 7617           </li>
 7618           <li>for each <fieldlink id="can_retransform_classes"
 7619                      struct="jvmtiCapabilities">retransformation
 7620                                                 incapable</fieldlink>
 7621             agent which received a
 7622             <code>ClassFileLoadHook</code> event during the previous
 7623             load or redefine, the bytes it returned
 7624             (via the <code>new_class_data</code> parameter)
 7625             are reused as the output of the transformation;
 7626             note that this is equivalent to reapplying
 7627             the previous transformation, unaltered. except that
 7628             the <code>ClassFileLoadHook</code> event
 7629             is <b>not</b> sent to these agents
 7630           </li>
 7631           <li>for each <fieldlink id="can_retransform_classes"
 7632                      struct="jvmtiCapabilities">retransformation
 7633                                                 capable</fieldlink>
 7634             agent, the <code>ClassFileLoadHook</code> event is sent,
 7635             allowing a new transformation to be applied
 7636           </li>
 7637           <li>the transformed class file bytes are installed as the new
 7638             definition of the class
 7639           </li>
 7640         </ul>
 7641         See the <eventlink id="ClassFileLoadHook"/> event for more details.
 7642         <p/>
 7643         The initial class file bytes represent the bytes passed to
 7644         <code>ClassLoader.defineClass</code>
 7645         or <code>RedefineClasses</code> (before any transformations
 7646         were applied), however they may not exactly match them.
 7647         The constant pool may differ in ways described in
 7648         <functionlink id="GetConstantPool"/>.
 7649         Constant pool indices in the bytecodes of methods will correspond.
 7650         Some attributes may not be present.
 7651         Where order is not meaningful, for example the order of methods,
 7652         order may not be preserved.
 7653         <p/>
 7654         Retransformation can cause new versions of methods to be installed.
 7655         Old method versions may become
 7656         <internallink id="obsoleteMethods">obsolete</internallink>
 7657         The new method version will be used on new invokes.
 7658         If a method has active stack frames, those active frames continue to
 7659         run the bytecodes of the original method version.
 7660         <p/>
 7661         This function does not cause any initialization except that which
 7662         would occur under the customary JVM semantics.
 7663         In other words, retransforming a class does not cause its initializers to be
 7664         run. The values of static fields will remain as they were
 7665         prior to the call.
 7666         <p/>
 7667         Threads need not be suspended.
 7668         <p/>
 7669         All breakpoints in the class are cleared.
 7670         <p/>
 7671         All attributes are updated.
 7672         <p/>
 7673         Instances of the retransformed class are not affected -- fields retain their
 7674         previous values.
 7675         <functionlink id="GetTag">Tags</functionlink> on the instances are
 7676         also unaffected.
 7677         <p/>
 7678         In response to this call, no events other than the
 7679         <eventlink id="ClassFileLoadHook"/> event
 7680         will be sent.
 7681         <p/>
 7682         The retransformation may change method bodies, the constant pool and attributes
 7683         (unless explicitly prohibited).
 7684         The retransformation must not add, remove or rename fields or methods, change the
 7685         signatures of methods, change modifiers, or change inheritance.
 7686         The retransformation must not change the <code>NestHost</code>,
 7687         <code>NestMembers</code>, <code>Record</code>, or <code>PermittedSubclasses</code>
 7688         attributes.
 7689         These restrictions may be lifted in future versions.
 7690         See the error return description below for information on error codes
 7691         returned if an unsupported retransformation is attempted.
 7692         The class file bytes are not verified or installed until they have passed
 7693         through the chain of <eventlink id="ClassFileLoadHook"/> events, thus the
 7694         returned error code reflects the result of the transformations.
 7695         If any error code is returned other than <code>JVMTI_ERROR_NONE</code>,
 7696         none of the classes to be retransformed will have a new definition installed.
 7697         When this function returns (with the error code of <code>JVMTI_ERROR_NONE</code>)
 7698         all of the classes to be retransformed will have their new definitions installed.
 7699       </description>
 7700       <origin>new</origin>
 7701       <capabilities>
 7702         <required id="can_retransform_classes"></required>
 7703         <capability id="can_retransform_any_class"></capability>
 7704       </capabilities>
 7705       <parameters>
 7706         <param id="class_count">
 7707           <jint min="0"/>
 7708           <description>
 7709             The number of classes to be retransformed.
 7710           </description>
 7711         </param>
 7712         <param id="classes">
 7713           <inbuf incount="class_count"><jclass/></inbuf>
 7714           <description>
 7715             The array of classes to be retransformed.
 7716           </description>
 7717         </param>
 7718       </parameters>
 7719       <errors>
 7720         <error id="JVMTI_ERROR_UNMODIFIABLE_CLASS">
 7721           One of the <paramlink id="classes"/> cannot be modified.
 7722           See <functionlink id="IsModifiableClass"/>.
 7723         </error>
 7724         <error id="JVMTI_ERROR_INVALID_CLASS">
 7725           One of the <paramlink id="classes"/> is not a valid class.
 7726         </error>
 7727         <error id="JVMTI_ERROR_UNSUPPORTED_VERSION">
 7728           A retransformed class file has a version number not supported by this VM.
 7729         </error>
 7730         <error id="JVMTI_ERROR_INVALID_CLASS_FORMAT">
 7731           A retransformed class file is malformed (The VM would return a <code>ClassFormatError</code>).
 7732         </error>
 7733         <error id="JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION">
 7734           The retransformed class file definitions would lead to a circular definition
 7735           (the VM would return a <code>ClassCircularityError</code>).
 7736         </error>
 7737         <error id="JVMTI_ERROR_FAILS_VERIFICATION">
 7738           The retransformed class file bytes fail verification.
 7739         </error>
 7740         <error id="JVMTI_ERROR_NAMES_DONT_MATCH">
 7741           The class name defined in a retransformed class file is
 7742           different from the name in the old class object.
 7743         </error>
 7744         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED">
 7745           A retransformed class file would require adding a method.
 7746         </error>
 7747         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED">
 7748           A retransformed class file changes a field.
 7749         </error>
 7750         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED">
 7751           A direct superclass is different for a retransformed class file,
 7752           or the set of directly implemented
 7753           interfaces is different.
 7754         </error>
 7755         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED">
 7756           A retransformed class file does not declare a method
 7757           declared in the old class version.
 7758         </error>
 7759         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED">
 7760           A retransformed class file has unsupported differences in class attributes.
 7761         </error>
 7762         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED">
 7763           A retransformed class file has different class modifiers.
 7764         </error>
 7765         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED">
 7766           A method in the retransformed class file has different modifiers
 7767           than its counterpart in the old class version.
 7768         </error>
 7769       </errors>
 7770     </function>
 7771 
 7772     <function id="RedefineClasses" jkernel="yes" num="87">
 7773       <synopsis>Redefine Classes</synopsis>
 7774       <typedef id="jvmtiClassDefinition" label="Class redefinition description">
 7775         <field id="klass">
 7776           <jclass/>
 7777             <description>
 7778               Class object for this class
 7779             </description>
 7780         </field>
 7781         <field id="class_byte_count">
 7782           <jint/>
 7783           <description>
 7784             Number of bytes defining class (below)
 7785           </description>
 7786         </field>
 7787         <field id="class_bytes">
 7788           <inbuf incount="class_byte_count"><uchar/></inbuf>
 7789           <description>
 7790             Bytes defining class (in <vmspec chapter="4"/>)
 7791           </description>
 7792         </field>
 7793       </typedef>
 7794       <description>
 7795         All classes given are redefined according to the definitions
 7796         supplied.
 7797         This function is used to replace the definition of a class
 7798         with a new definition, as might be needed in fix-and-continue
 7799         debugging.
 7800         Where the existing class file bytes are to be transformed, for
 7801         example in
 7802         <internallink id="bci">bytecode instrumentation</internallink>,
 7803         <functionlink id="RetransformClasses"/> should be used.
 7804         <p/>
 7805         Redefinition can cause new versions of methods to be installed.
 7806         Old method versions may become
 7807         <internallink id="obsoleteMethods">obsolete</internallink>
 7808         The new method version will be used on new invokes.
 7809         If a method has active stack frames, those active frames continue to
 7810         run the bytecodes of the original method version.
 7811         If resetting of stack frames is desired, use
 7812         <functionlink id="PopFrame"></functionlink>
 7813         to pop frames with obsolete method versions.
 7814         <p/>
 7815         This function does not cause any initialization except that which
 7816         would occur under the customary JVM semantics.
 7817         In other words, redefining a class does not cause its initializers to be
 7818         run. The values of static fields will remain as they were
 7819         prior to the call.
 7820         <p/>
 7821         Threads need not be suspended.
 7822         <p/>
 7823         All breakpoints in the class are cleared.
 7824         <p/>
 7825         All attributes are updated.
 7826         <p/>
 7827         Instances of the redefined class are not affected -- fields retain their
 7828         previous values.
 7829         <functionlink id="GetTag">Tags</functionlink> on the instances are
 7830         also unaffected.
 7831         <p/>
 7832         In response to this call, the <jvmti/> event
 7833         <eventlink id="ClassFileLoadHook">Class File Load Hook</eventlink>
 7834         will be sent (if enabled), but no other <jvmti/> events will be sent.
 7835         <p/>
 7836         The redefinition may change method bodies, the constant pool and attributes
 7837         (unless explicitly prohibited).
 7838         The redefinition must not add, remove or rename fields or methods, change the
 7839         signatures of methods, change modifiers, or change inheritance.
 7840         The redefinition must not change the <code>NestHost</code>,
 7841         <code>NestMembers</code>, <code>Record</code>, or <code>PermittedSubclasses</code>
 7842         attributes.
 7843         These restrictions may be lifted in future versions.
 7844         See the error return description below for information on error codes
 7845         returned if an unsupported redefinition is attempted.
 7846         The class file bytes are not verified or installed until they have passed
 7847         through the chain of <eventlink id="ClassFileLoadHook"/> events, thus the
 7848         returned error code reflects the result of the transformations applied
 7849         to the bytes passed into <paramlink id="class_definitions"/>.
 7850         If any error code is returned other than <code>JVMTI_ERROR_NONE</code>,
 7851         none of the classes to be redefined will have a new definition installed.
 7852         When this function returns (with the error code of <code>JVMTI_ERROR_NONE</code>)
 7853         all of the classes to be redefined will have their new definitions installed.
 7854       </description>
 7855       <origin>jvmdi</origin>
 7856       <capabilities>
 7857         <required id="can_redefine_classes"></required>
 7858         <capability id="can_redefine_any_class"></capability>
 7859       </capabilities>
 7860       <parameters>
 7861         <param id="class_count">
 7862           <jint min="0"/>
 7863           <description>
 7864             The number of classes specified in <code>class_definitions</code>
 7865           </description>
 7866         </param>
 7867         <param id="class_definitions">
 7868           <inbuf incount="class_count"><struct>jvmtiClassDefinition</struct></inbuf>
 7869           <description>
 7870             The array of new class definitions
 7871           </description>
 7872         </param>
 7873       </parameters>
 7874       <errors>
 7875         <error id="JVMTI_ERROR_NULL_POINTER">
 7876           One of <code>class_bytes</code> is <code>NULL</code>.
 7877         </error>
 7878         <error id="JVMTI_ERROR_UNMODIFIABLE_CLASS">
 7879           An element of <code>class_definitions</code> cannot be modified.
 7880           See <functionlink id="IsModifiableClass"/>.
 7881         </error>
 7882         <error id="JVMTI_ERROR_INVALID_CLASS">
 7883           An element of <code>class_definitions</code> is not a valid class.
 7884         </error>
 7885         <error id="JVMTI_ERROR_UNSUPPORTED_VERSION">
 7886           A new class file has a version number not supported by this VM.
 7887         </error>
 7888         <error id="JVMTI_ERROR_INVALID_CLASS_FORMAT">
 7889           A new class file is malformed (The VM would return a <code>ClassFormatError</code>).
 7890         </error>
 7891         <error id="JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION">
 7892           The new class file definitions would lead to a circular definition
 7893           (the VM would return a <code>ClassCircularityError</code>).
 7894         </error>
 7895         <error id="JVMTI_ERROR_FAILS_VERIFICATION">
 7896           The class bytes fail verification.
 7897         </error>
 7898         <error id="JVMTI_ERROR_NAMES_DONT_MATCH">
 7899           The class name defined in a new class file is
 7900           different from the name in the old class object.
 7901         </error>
 7902         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED">
 7903           A new class file would require adding a method.
 7904         </error>
 7905         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED">
 7906           A new class version changes a field.
 7907         </error>
 7908         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED">
 7909           A direct superclass is different for a new class
 7910           version, or the set of directly implemented
 7911           interfaces is different.
 7912         </error>
 7913         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED">
 7914           A new class version does not declare a method
 7915           declared in the old class version.
 7916         </error>
 7917         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED">
 7918           A new class version has unsupported differences in class attributes.
 7919         </error>
 7920         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED">
 7921           A new class version has different modifiers.
 7922         </error>
 7923         <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED">
 7924           A method in the new class version has different modifiers
 7925           than its counterpart in the old class version.
 7926         </error>
 7927         <error id="JVMTI_ERROR_UNMODIFIABLE_MODULE">
 7928           A module cannot be modified.
 7929           See <functionlink id="IsModifiableModule"/>.
 7930         </error>
 7931       </errors>
 7932     </function>
 7933 
 7934   </category>
 7935 
 7936   <category id="object" label="Object">
 7937 
 7938     <function id="GetObjectSize" jkernel="yes" phase="start" num="154">
 7939       <synopsis>Get Object Size</synopsis>
 7940       <description>
 7941         For the object indicated by <code>object</code>,
 7942         return via <code>size_ptr</code> the size of the object.
 7943         This size is an implementation-specific approximation of
 7944         the amount of storage consumed by this object.
 7945         It may include some or all of the object's overhead, and thus
 7946         is useful for comparison within an implementation but not
 7947         between implementations.
 7948         The estimate may change during a single invocation of the JVM.
 7949       </description>
 7950       <origin>new</origin>
 7951       <capabilities>
 7952       </capabilities>
 7953       <parameters>
 7954         <param id="object">
 7955           <jobject/>
 7956             <description>
 7957               The object to query.
 7958             </description>
 7959         </param>
 7960         <param id="size_ptr">
 7961           <outptr><jlong/></outptr>
 7962           <description>
 7963             On return, points to the object's size in bytes.
 7964           </description>
 7965         </param>
 7966       </parameters>
 7967       <errors>
 7968       </errors>
 7969     </function>
 7970 
 7971     <function id="GetObjectHashCode" phase="start" num="58">
 7972       <synopsis>Get Object Hash Code</synopsis>
 7973       <description>
 7974         For the object indicated by <code>object</code>,
 7975         return via <code>hash_code_ptr</code> a hash code.
 7976         This hash code could be used to maintain a hash table of object references,
 7977         however, on some implementations this can cause significant performance
 7978         impacts--in most cases
 7979         <internallink id="Heap">tags</internallink>
 7980         will be a more efficient means of associating information with objects.
 7981         This function guarantees
 7982         the same hash code value for a particular object throughout its life
 7983       </description>
 7984       <origin>jvmdi</origin>
 7985       <capabilities>
 7986       </capabilities>
 7987       <parameters>
 7988         <param id="object">
 7989           <jobject/>
 7990             <description>
 7991               The object to query.
 7992             </description>
 7993         </param>
 7994         <param id="hash_code_ptr">
 7995           <outptr><jint/></outptr>
 7996           <description>
 7997             On return, points to the object's hash code.
 7998           </description>
 7999         </param>
 8000       </parameters>
 8001       <errors>
 8002       </errors>
 8003     </function>
 8004 
 8005     <function id="GetObjectMonitorUsage" num="59">
 8006       <synopsis>Get Object Monitor Usage</synopsis>
 8007       <typedef id="jvmtiMonitorUsage" label="Object monitor usage information">
 8008         <field id="owner">
 8009           <jthread/>
 8010             <description>
 8011               The thread owning this monitor, or <code>NULL</code> if unused
 8012             </description>
 8013         </field>
 8014         <field id="entry_count">
 8015           <jint/>
 8016           <description>
 8017             The number of times the owning thread has entered the monitor
 8018           </description>
 8019         </field>
 8020         <field id="waiter_count">
 8021           <jint/>
 8022           <description>
 8023             The number of threads waiting to own this monitor
 8024           </description>
 8025         </field>
 8026         <field id="waiters">
 8027           <allocfieldbuf><jthread/></allocfieldbuf>
 8028             <description>
 8029               The <code>waiter_count</code> waiting threads
 8030             </description>
 8031         </field>
 8032         <field id="notify_waiter_count">
 8033           <jint/>
 8034           <description>
 8035             The number of threads waiting to be notified by this monitor
 8036           </description>
 8037         </field>
 8038         <field id="notify_waiters">
 8039           <allocfieldbuf><jthread/></allocfieldbuf>
 8040             <description>
 8041               The <code>notify_waiter_count</code> threads waiting to be notified
 8042             </description>
 8043         </field>
 8044       </typedef>
 8045       <description>
 8046         Get information about the object's monitor.
 8047         The fields of the <functionlink id="jvmtiMonitorUsage"></functionlink> structure
 8048         are filled in with information about usage of the monitor.
 8049           <todo>
 8050             Decide and then clarify suspend requirements.
 8051           </todo>
 8052       </description>
 8053       <origin>jvmdi</origin>
 8054       <capabilities>
 8055         <required id="can_get_monitor_info"></required>
 8056       </capabilities>
 8057       <parameters>
 8058         <param id="object">
 8059           <jobject/>
 8060             <description>
 8061               The object to query.
 8062             </description>
 8063         </param>
 8064         <param id="info_ptr">
 8065           <outptr><struct>jvmtiMonitorUsage</struct></outptr>
 8066           <description>
 8067             On return, filled with monitor information for the
 8068             specified object.
 8069           </description>
 8070         </param>
 8071       </parameters>
 8072       <errors>
 8073       </errors>
 8074     </function>
 8075 
 8076     <elide>
 8077     <function id="GetObjectMonitors" num="116">
 8078       <synopsis>Get Object Monitors</synopsis>
 8079       <description>
 8080         Return the list of object monitors.
 8081         <p/>
 8082         Note: details about each monitor can be examined with
 8083         <functionlink id="GetObjectMonitorUsage"></functionlink>.
 8084       </description>
 8085       <origin>new</origin>
 8086       <capabilities>
 8087         <required id="can_get_monitor_info"></required>
 8088       </capabilities>
 8089       <parameters>
 8090         <param id="monitorCnt">
 8091           <outptr><jint/></outptr>
 8092           <description>
 8093             On return, pointer to the number
 8094             of monitors returned in <code>monitors_ptr</code>.
 8095           </description>
 8096         </param>
 8097         <param id="monitors_ptr">
 8098           <allocbuf outcount="monitorCnt"><jobject/></allocbuf>
 8099             <description>
 8100               On return, pointer to the monitor list.
 8101             </description>
 8102         </param>
 8103       </parameters>
 8104       <errors>
 8105       </errors>
 8106     </function>
 8107     </elide>
 8108 
 8109   </category>
 8110 
 8111   <category id="fieldCategory" label="Field">
 8112 
 8113     <intro>
 8114     </intro>
 8115 
 8116     <function id="GetFieldName" phase="start" num="60">
 8117       <synopsis>Get Field Name (and Signature)</synopsis>
 8118       <description>
 8119         For the field indicated by <paramlink id="klass"/> and <paramlink id="field"/>,
 8120         return the field name via <paramlink id="name_ptr"/> and field signature via
 8121         <paramlink id="signature_ptr"/>.
 8122         <p/>
 8123         Field signatures are defined in the
 8124         <externallink id="jni/index.html">JNI Specification</externallink>
 8125         and are referred to as <code>field descriptors</code> in
 8126         <vmspec chapter="4.3.2"/>.
 8127       </description>
 8128       <origin>jvmdiClone</origin>
 8129       <capabilities>
 8130       </capabilities>
 8131       <parameters>
 8132         <param id="klass">
 8133           <jclass field="field"/>
 8134             <description>
 8135               The class of the field to query.
 8136             </description>
 8137         </param>
 8138         <param id="field">
 8139           <jfieldID class="klass"/>
 8140             <description>
 8141               The field to query.
 8142             </description>
 8143         </param>
 8144         <param id="name_ptr">
 8145           <allocbuf>
 8146             <char/>
 8147             <nullok>the name is not returned</nullok>
 8148           </allocbuf>
 8149           <description>
 8150             On return, points to the field name, encoded as a
 8151             <internallink id="mUTF">modified UTF-8</internallink> string.
 8152           </description>
 8153         </param>
 8154         <param id="signature_ptr">
 8155           <allocbuf>
 8156             <char/>
 8157             <nullok>the signature is not returned</nullok>
 8158           </allocbuf>
 8159           <description>
 8160             On return, points to the field signature, encoded as a
 8161             <internallink id="mUTF">modified UTF-8</internallink> string.
 8162           </description>
 8163         </param>
 8164         <param id="generic_ptr">
 8165           <allocbuf>
 8166             <char/>
 8167             <nullok>the generic signature is not returned</nullok>
 8168           </allocbuf>
 8169           <description>
 8170             On return, points to the generic signature of the field, encoded as a
 8171             <internallink id="mUTF">modified UTF-8</internallink> string.
 8172             If there is no generic signature attribute for the field, then,
 8173             on return, points to <code>NULL</code>.
 8174           </description>
 8175         </param>
 8176       </parameters>
 8177       <errors>
 8178       </errors>
 8179     </function>
 8180 
 8181     <function id="GetFieldDeclaringClass" phase="start" num="61">
 8182       <synopsis>Get Field Declaring Class</synopsis>
 8183       <description>
 8184         For the field indicated by <code>klass</code> and <code>field</code>
 8185         return the class that defined it via <code>declaring_class_ptr</code>.
 8186         The declaring class will either be <code>klass</code>, a superclass, or
 8187         an implemented interface.
 8188       </description>
 8189       <origin>jvmdi</origin>
 8190       <capabilities>
 8191       </capabilities>
 8192       <parameters>
 8193         <param id="klass">
 8194           <jclass field="field"/>
 8195             <description>
 8196               The class to query.
 8197             </description>
 8198         </param>
 8199         <param id="field">
 8200           <jfieldID class="klass"/>
 8201             <description>
 8202               The field to query.
 8203             </description>
 8204         </param>
 8205         <param id="declaring_class_ptr">
 8206           <outptr><jclass/></outptr>
 8207             <description>
 8208               On return, points to the declaring class
 8209             </description>
 8210         </param>
 8211       </parameters>
 8212       <errors>
 8213       </errors>
 8214     </function>
 8215 
 8216     <function id="GetFieldModifiers" phase="start" num="62">
 8217       <synopsis>Get Field Modifiers</synopsis>
 8218       <description>
 8219         For the field indicated by <code>klass</code> and <code>field</code>
 8220         return the access flags via <code>modifiers_ptr</code>.
 8221         Access flags are defined in <vmspec chapter="4"/>.
 8222       </description>
 8223       <origin>jvmdi</origin>
 8224       <capabilities>
 8225       </capabilities>
 8226       <parameters>
 8227         <param id="klass">
 8228           <jclass field="field"/>
 8229             <description>
 8230               The class to query.
 8231             </description>
 8232         </param>
 8233         <param id="field">
 8234           <jfieldID class="klass"/>
 8235             <description>
 8236               The field to query.
 8237             </description>
 8238         </param>
 8239         <param id="modifiers_ptr">
 8240           <outptr><jint/></outptr>
 8241           <description>
 8242             On return, points to the access flags.
 8243           </description>
 8244         </param>
 8245       </parameters>
 8246       <errors>
 8247       </errors>
 8248     </function>
 8249 
 8250     <function id="IsFieldSynthetic" phase="start" num="63">
 8251       <synopsis>Is Field Synthetic</synopsis>
 8252       <description>
 8253         For the field indicated by <code>klass</code> and <code>field</code>, return a
 8254         value indicating whether the field is synthetic via <code>is_synthetic_ptr</code>.
 8255         Synthetic fields are generated by the compiler but not present in the
 8256         original source code.
 8257       </description>
 8258       <origin>jvmdi</origin>
 8259       <capabilities>
 8260         <required id="can_get_synthetic_attribute"></required>
 8261       </capabilities>
 8262       <parameters>
 8263         <param id="klass">
 8264           <jclass field="field"/>
 8265             <description>
 8266               The class of the field to query.
 8267             </description>
 8268         </param>
 8269         <param id="field">
 8270           <jfieldID class="klass"/>
 8271             <description>
 8272               The field to query.
 8273             </description>
 8274         </param>
 8275         <param id="is_synthetic_ptr">
 8276           <outptr><jboolean/></outptr>
 8277           <description>
 8278             On return, points to the boolean result of this function.
 8279           </description>
 8280         </param>
 8281       </parameters>
 8282       <errors>
 8283       </errors>
 8284     </function>
 8285 
 8286   </category>
 8287 
 8288   <category id="method" label="Method">
 8289 
 8290     <intro>
 8291       These functions provide information about a method (represented as a
 8292       <typelink id="jmethodID"/>) and set how methods are processed.
 8293     </intro>
 8294 
 8295     <intro id="obsoleteMethods" label="Obsolete Methods">
 8296       The functions <functionlink id="RetransformClasses"/> and
 8297       <functionlink id="RedefineClasses"/> can cause new versions
 8298       of methods to be installed.
 8299       An original version of a method is considered equivalent
 8300       to the new version if:
 8301       <ul>
 8302         <li>their bytecodes are the same except for indices into the
 8303           constant pool and </li>
 8304         <li>the referenced constants are equal.</li>
 8305       </ul>
 8306       An original method version which is not equivalent to the
 8307       new method version is called obsolete and is assigned a new method ID;
 8308       the original method ID now refers to the new method version.
 8309       A method ID can be tested for obsolescence with
 8310       <functionlink id="IsMethodObsolete"/>.
 8311     </intro>
 8312 
 8313     <function id="GetMethodName" phase="start" num="64">
 8314       <synopsis>Get Method Name (and Signature)</synopsis>
 8315       <description>
 8316         For the method indicated by <code>method</code>,
 8317         return the method name via <code>name_ptr</code> and method signature via
 8318         <code>signature_ptr</code>.
 8319         <p/>
 8320         Method signatures are defined in the
 8321         <externallink id="jni/index.html">JNI Specification</externallink>
 8322         and are referred to as <code>method descriptors</code> in
 8323         <vmspec chapter="4.3.3"/>.
 8324         Note this is different
 8325         than method signatures as defined in the <i>Java Language Specification</i>.
 8326       </description>
 8327       <origin>jvmdiClone</origin>
 8328       <capabilities>
 8329       </capabilities>
 8330       <parameters>
 8331         <param id="method">
 8332           <jmethodID/>
 8333             <description>
 8334               The method to query.
 8335             </description>
 8336         </param>
 8337         <param id="name_ptr">
 8338           <allocbuf>
 8339             <char/>
 8340             <nullok>the name is not returned</nullok>
 8341           </allocbuf>
 8342           <description>
 8343             On return, points to the method name, encoded as a
 8344             <internallink id="mUTF">modified UTF-8</internallink> string.
 8345           </description>
 8346         </param>
 8347         <param id="signature_ptr">
 8348           <allocbuf>
 8349             <char/>
 8350             <nullok>the signature is not returned</nullok>
 8351           </allocbuf>
 8352           <description>
 8353             On return, points to the method signature, encoded as a
 8354             <internallink id="mUTF">modified UTF-8</internallink> string.
 8355           </description>
 8356         </param>
 8357         <param id="generic_ptr">
 8358           <allocbuf>
 8359             <char/>
 8360             <nullok>the generic signature is not returned</nullok>
 8361           </allocbuf>
 8362           <description>
 8363             On return, points to the generic signature of the method, encoded as a
 8364             <internallink id="mUTF">modified UTF-8</internallink> string.
 8365             If there is no generic signature attribute for the method, then,
 8366             on return, points to <code>NULL</code>.
 8367           </description>
 8368         </param>
 8369       </parameters>
 8370       <errors>
 8371       </errors>
 8372     </function>
 8373 
 8374     <function id="GetMethodDeclaringClass" phase="start" num="65">
 8375       <synopsis>Get Method Declaring Class</synopsis>
 8376       <description>
 8377         For the method indicated by <code>method</code>,
 8378         return the class that defined it via <code>declaring_class_ptr</code>.
 8379       </description>
 8380       <origin>jvmdi</origin>
 8381       <capabilities>
 8382       </capabilities>
 8383       <parameters>
 8384         <param id="klass">
 8385           <jclass method="method"/>
 8386             <description>
 8387               The class to query.
 8388             </description>
 8389         </param>
 8390         <param id="method">
 8391           <jmethodID class="klass"/>
 8392             <description>
 8393               The method to query.
 8394             </description>
 8395         </param>
 8396         <param id="declaring_class_ptr">
 8397           <outptr><jclass/></outptr>
 8398             <description>
 8399               On return, points to the declaring class
 8400             </description>
 8401         </param>
 8402       </parameters>
 8403       <errors>
 8404       </errors>
 8405     </function>
 8406 
 8407     <function id="GetMethodModifiers" phase="start" num="66">
 8408       <synopsis>Get Method Modifiers</synopsis>
 8409       <description>
 8410         For the method indicated by <code>method</code>,
 8411         return the access flags via <code>modifiers_ptr</code>.
 8412         Access flags are defined in <vmspec chapter="4"/>.
 8413       </description>
 8414       <origin>jvmdi</origin>
 8415       <capabilities>
 8416       </capabilities>
 8417       <parameters>
 8418         <param id="klass">
 8419           <jclass method="method"/>
 8420             <description>
 8421               The class to query.
 8422             </description>
 8423         </param>
 8424         <param id="method">
 8425           <jmethodID class="klass"/>
 8426             <description>
 8427               The method to query.
 8428             </description>
 8429         </param>
 8430         <param id="modifiers_ptr">
 8431           <outptr><jint/></outptr>
 8432           <description>
 8433             On return, points to the access flags.
 8434           </description>
 8435         </param>
 8436       </parameters>
 8437       <errors>
 8438       </errors>
 8439     </function>
 8440 
 8441     <function id="GetMaxLocals" phase="start" num="68">
 8442       <synopsis>Get Max Locals</synopsis>
 8443       <description>
 8444           For the method indicated by <code>method</code>,
 8445           return the number of local variable slots used by the method,
 8446           including the local variables used to pass parameters to the
 8447           method on its invocation.
 8448           <p/>
 8449           See <code>max_locals</code> in <vmspec chapter="4.7.3"/>.
 8450       </description>
 8451       <origin>jvmdi</origin>
 8452       <capabilities>
 8453       </capabilities>
 8454       <parameters>
 8455         <param id="klass">
 8456           <jclass method="method"/>
 8457             <description>
 8458               The class to query.
 8459             </description>
 8460         </param>
 8461         <param id="method">
 8462           <jmethodID class="klass" native="error"/>
 8463             <description>
 8464               The method to query.
 8465             </description>
 8466         </param>
 8467         <param id="max_ptr">
 8468           <outptr><jint/></outptr>
 8469           <description>
 8470             On return, points to the maximum number of local slots
 8471           </description>
 8472         </param>
 8473       </parameters>
 8474       <errors>
 8475       </errors>
 8476     </function>
 8477 
 8478     <function id="GetArgumentsSize" phase="start" num="69">
 8479       <synopsis>Get Arguments Size</synopsis>
 8480       <description>
 8481         For the method indicated by <code>method</code>,
 8482         return via <code>max_ptr</code> the number of local variable slots used
 8483         by the method's arguments.
 8484         Note that two-word arguments use two slots.
 8485       </description>
 8486       <origin>jvmdi</origin>
 8487       <capabilities>
 8488       </capabilities>
 8489       <parameters>
 8490         <param id="klass">
 8491           <jclass method="method"/>
 8492             <description>
 8493               The class to query.
 8494             </description>
 8495         </param>
 8496         <param id="method">
 8497           <jmethodID class="klass" native="error"/>
 8498             <description>
 8499               The method to query.
 8500             </description>
 8501         </param>
 8502         <param id="size_ptr">
 8503           <outptr><jint/></outptr>
 8504           <description>
 8505             On return, points to the number of argument slots
 8506           </description>
 8507         </param>
 8508       </parameters>
 8509       <errors>
 8510       </errors>
 8511     </function>
 8512 
 8513     <function id="GetLineNumberTable" phase="start" num="70">
 8514       <synopsis>Get Line Number Table</synopsis>
 8515       <typedef id="jvmtiLineNumberEntry" label="Line number table entry">
 8516         <field id="start_location">
 8517           <jlocation/>
 8518           <description>
 8519             the <datalink id="jlocation"></datalink> where the line begins
 8520           </description>
 8521         </field>
 8522         <field id="line_number">
 8523           <jint/>
 8524           <description>
 8525             the line number
 8526           </description>
 8527         </field>
 8528       </typedef>
 8529       <description>
 8530         For the method indicated by <code>method</code>,
 8531         return a table of source line number entries. The size of the table is
 8532         returned via <code>entry_count_ptr</code> and the table itself is
 8533         returned via <code>table_ptr</code>.
 8534       </description>
 8535       <origin>jvmdi</origin>
 8536       <capabilities>
 8537         <required id="can_get_line_numbers"></required>
 8538       </capabilities>
 8539       <parameters>
 8540         <param id="klass">
 8541           <jclass method="method"/>
 8542             <description>
 8543               The class to query.
 8544             </description>
 8545         </param>
 8546         <param id="method">
 8547           <jmethodID class="klass" native="error"/>
 8548             <description>
 8549               The method to query.
 8550             </description>
 8551         </param>
 8552         <param id="entry_count_ptr">
 8553           <outptr><jint/></outptr>
 8554           <description>
 8555             On return, points to the number of entries in the table
 8556           </description>
 8557         </param>
 8558         <param id="table_ptr">
 8559           <allocbuf outcount="entry_count_ptr"><struct>jvmtiLineNumberEntry</struct></allocbuf>
 8560           <description>
 8561             On return, points to the line number table pointer.
 8562           </description>
 8563         </param>
 8564       </parameters>
 8565       <errors>
 8566         <error id="JVMTI_ERROR_ABSENT_INFORMATION">
 8567           Class information does not include line numbers.
 8568         </error>
 8569       </errors>
 8570     </function>
 8571 
 8572     <function id="GetMethodLocation" phase="start" num="71">
 8573       <synopsis>Get Method Location</synopsis>
 8574       <description>
 8575         For the method indicated by <code>method</code>,
 8576         return the beginning and ending addresses through
 8577         <code>start_location_ptr</code> and <code>end_location_ptr</code>. In a
 8578         conventional bytecode indexing scheme,
 8579         <code>start_location_ptr</code> will always point to zero
 8580         and <code>end_location_ptr</code>
 8581         will always point to the bytecode count minus one.
 8582       </description>
 8583       <origin>jvmdi</origin>
 8584       <capabilities>
 8585       </capabilities>
 8586       <parameters>
 8587         <param id="klass">
 8588           <jclass method="method"/>
 8589             <description>
 8590               The class to query.
 8591             </description>
 8592         </param>
 8593         <param id="method">
 8594           <jmethodID class="klass" native="error"/>
 8595             <description>
 8596               The method to query.
 8597             </description>
 8598         </param>
 8599         <param id="start_location_ptr">
 8600           <outptr><jlocation/></outptr>
 8601           <description>
 8602             On return, points to the first location, or
 8603             <code>-1</code> if location information is not available.
 8604             If the information is available and
 8605             <functionlink id="GetJLocationFormat"></functionlink>
 8606             returns <datalink id="JVMTI_JLOCATION_JVMBCI"></datalink>
 8607             then this will always be zero.
 8608           </description>
 8609         </param>
 8610         <param id="end_location_ptr">
 8611           <outptr><jlocation/></outptr>
 8612           <description>
 8613             On return, points to the last location,
 8614             or <code>-1</code> if location information is not available.
 8615           </description>
 8616         </param>
 8617       </parameters>
 8618       <errors>
 8619         <error id="JVMTI_ERROR_ABSENT_INFORMATION">
 8620           Class information does not include method sizes.
 8621         </error>
 8622       </errors>
 8623     </function>
 8624 
 8625     <function id="GetLocalVariableTable" num="72">
 8626       <synopsis>Get Local Variable Table</synopsis>
 8627       <typedef id="jvmtiLocalVariableEntry" label="Local variable table entry">
 8628         <field id="start_location">
 8629           <jlocation/>
 8630           <description>
 8631             The code array index where the local variable is first valid
 8632             (that is, where it must have a value).
 8633           </description>
 8634         </field>
 8635         <field id="length">
 8636           <jint/>
 8637           <description>
 8638             The length of the valid section for this local variable.
 8639             The last code array index where the local variable is valid
 8640             is <code>start_location + length</code>.
 8641           </description>
 8642         </field>
 8643         <field id="name">
 8644           <allocfieldbuf><char/></allocfieldbuf>
 8645           <description>
 8646             The local variable name, encoded as a
 8647             <internallink id="mUTF">modified UTF-8</internallink> string.
 8648           </description>
 8649         </field>
 8650         <field id="signature">
 8651           <allocfieldbuf><char/></allocfieldbuf>
 8652           <description>
 8653             The local variable's type signature, encoded as a
 8654             <internallink id="mUTF">modified UTF-8</internallink> string.
 8655             The signature format is the same as that defined in
 8656             <vmspec chapter="4.3.2"/>.
 8657           </description>
 8658         </field>
 8659         <field id="generic_signature">
 8660           <allocfieldbuf><char/></allocfieldbuf>
 8661           <description>
 8662             The local variable's generic signature, encoded as a
 8663             <internallink id="mUTF">modified UTF-8</internallink> string.
 8664             The value of this field will be <code>NULL</code> for any local
 8665             variable which does not have a generic type.
 8666           </description>
 8667         </field>
 8668         <field id="slot">
 8669           <jint/>
 8670           <description>
 8671             The local variable's slot.  See <internallink id="local">Local Variables</internallink>.
 8672           </description>
 8673         </field>
 8674       </typedef>
 8675       <description>
 8676         Return local variable information.
 8677       </description>
 8678       <origin>jvmdiClone</origin>
 8679       <capabilities>
 8680         <required id="can_access_local_variables"></required>
 8681       </capabilities>
 8682       <parameters>
 8683         <param id="method">
 8684           <jmethodID native="error"/>
 8685             <description>
 8686               The method to query.
 8687             </description>
 8688         </param>
 8689         <param id="entry_count_ptr">
 8690           <outptr><jint/></outptr>
 8691           <description>
 8692             On return, points to the number of entries in the table
 8693           </description>
 8694         </param>
 8695         <param id="table_ptr">
 8696           <allocbuf outcount="entry_count_ptr"><struct>jvmtiLocalVariableEntry</struct></allocbuf>
 8697           <description>
 8698             On return, points to an array of local variable table entries.
 8699           </description>
 8700         </param>
 8701       </parameters>
 8702       <errors>
 8703         <error id="JVMTI_ERROR_ABSENT_INFORMATION">
 8704           Class information does not include local variable
 8705           information.
 8706         </error>
 8707       </errors>
 8708     </function>
 8709 
 8710     <function id="GetBytecodes" phase="start" num="75">
 8711       <synopsis>Get Bytecodes</synopsis>
 8712       <description>
 8713         For the method indicated by <code>method</code>,
 8714         return the bytecodes that implement the method. The number of
 8715         bytecodes is returned via <code>bytecode_count_ptr</code>. The bytecodes
 8716         themselves are returned via <code>bytecodes_ptr</code>.
 8717       </description>
 8718       <origin>jvmdi</origin>
 8719       <capabilities>
 8720         <required id="can_get_bytecodes"></required>
 8721       </capabilities>
 8722       <parameters>
 8723         <param id="klass">
 8724           <jclass method="method"/>
 8725             <description>
 8726               The class to query.
 8727             </description>
 8728         </param>
 8729         <param id="method">
 8730           <jmethodID class="klass" native="error"/>
 8731             <description>
 8732               The method to query.
 8733             </description>
 8734         </param>
 8735         <param id="bytecode_count_ptr">
 8736           <outptr><jint/></outptr>
 8737           <description>
 8738             On return, points to the length of the bytecode array
 8739           </description>
 8740         </param>
 8741         <param id="bytecodes_ptr">
 8742           <allocbuf outcount="bytecode_count_ptr"><uchar/></allocbuf>
 8743           <description>
 8744             On return, points to the pointer to the bytecode array
 8745           </description>
 8746         </param>
 8747       </parameters>
 8748       <errors>
 8749       </errors>
 8750     </function>
 8751 
 8752     <function id="IsMethodNative" phase="start" num="76">
 8753       <synopsis>Is Method Native</synopsis>
 8754       <description>
 8755         For the method indicated by <code>method</code>, return a
 8756         value indicating whether the method is native via <code>is_native_ptr</code>
 8757       </description>
 8758       <origin>jvmdi</origin>
 8759       <capabilities>
 8760       </capabilities>
 8761       <parameters>
 8762         <param id="klass">
 8763           <jclass method="method"/>
 8764             <description>
 8765               The class to query.
 8766             </description>
 8767         </param>
 8768         <param id="method">
 8769           <jmethodID class="klass"/>
 8770             <description>
 8771               The method to query.
 8772             </description>
 8773         </param>
 8774         <param id="is_native_ptr">
 8775           <outptr><jboolean/></outptr>
 8776           <description>
 8777             On return, points to the boolean result of this function.
 8778           </description>
 8779         </param>
 8780       </parameters>
 8781       <errors>
 8782       </errors>
 8783     </function>
 8784 
 8785     <function id="IsMethodSynthetic" phase="start" num="77">
 8786       <synopsis>Is Method Synthetic</synopsis>
 8787       <description>
 8788         For the method indicated by <code>method</code>, return a
 8789         value indicating whether the method is synthetic via <code>is_synthetic_ptr</code>.
 8790         Synthetic methods are generated by the compiler but not present in the
 8791         original source code.
 8792       </description>
 8793       <origin>jvmdi</origin>
 8794       <capabilities>
 8795         <required id="can_get_synthetic_attribute"></required>
 8796       </capabilities>
 8797       <parameters>
 8798         <param id="klass">
 8799           <jclass method="method"/>
 8800             <description>
 8801               The class to query.
 8802             </description>
 8803         </param>
 8804         <param id="method">
 8805           <jmethodID class="klass"/>
 8806             <description>
 8807               The method to query.
 8808             </description>
 8809         </param>
 8810         <param id="is_synthetic_ptr">
 8811           <outptr><jboolean/></outptr>
 8812           <description>
 8813             On return, points to the boolean result of this function.
 8814           </description>
 8815         </param>
 8816       </parameters>
 8817       <errors>
 8818       </errors>
 8819     </function>
 8820 
 8821     <function id="IsMethodObsolete" phase="start" num="91">
 8822       <synopsis>Is Method Obsolete</synopsis>
 8823       <description>
 8824         Determine if a method ID refers to an
 8825         <internallink id="obsoleteMethods">obsolete</internallink>
 8826         method version.
 8827       </description>
 8828       <origin>jvmdi</origin>
 8829       <capabilities>
 8830       </capabilities>
 8831       <parameters>
 8832         <param id="klass">
 8833           <jclass method="method"/>
 8834             <description>
 8835               The class to query.
 8836             </description>
 8837         </param>
 8838         <param id="method">
 8839           <jmethodID class="klass"/>
 8840             <description>
 8841               The method ID to query.
 8842             </description>
 8843         </param>
 8844         <param id="is_obsolete_ptr">
 8845           <outptr><jboolean/></outptr>
 8846           <description>
 8847             On return, points to the boolean result of this function.
 8848           </description>
 8849         </param>
 8850       </parameters>
 8851       <errors>
 8852       </errors>
 8853     </function>
 8854 
 8855     <function id="SetNativeMethodPrefix" jkernel="yes" phase="any" num="73" since="1.1">
 8856       <synopsis>Set Native Method Prefix</synopsis>
 8857       <description>
 8858         This function modifies the failure handling of
 8859         native method resolution by allowing retry
 8860         with a prefix applied to the name.
 8861         When used with the
 8862         <eventlink id="ClassFileLoadHook">ClassFileLoadHook
 8863         event</eventlink>, it enables native methods to be
 8864         <internallink id="bci">instrumented</internallink>.
 8865         <p/>
 8866         Since native methods cannot be directly instrumented
 8867         (they have no bytecodes), they must be wrapped with
 8868         a non-native method which can be instrumented.
 8869         For example, if we had:
 8870         <example>
 8871 native boolean foo(int x);</example>
 8872         <p/>
 8873         We could transform the class file (with the
 8874         ClassFileLoadHook event) so that this becomes:
 8875         <example>
 8876 boolean foo(int x) {
 8877   <i>... record entry to foo ...</i>
 8878   return wrapped_foo(x);
 8879 }
 8880 
 8881 native boolean wrapped_foo(int x);</example>
 8882         <p/>
 8883         Where foo becomes a wrapper for the actual native method
 8884         with the appended prefix "wrapped_".  Note that
 8885         "wrapped_" would be a poor choice of prefix since it
 8886         might conceivably form the name of an existing method
 8887         thus something like "$$$MyAgentWrapped$$$_" would be
 8888         better but would make these examples less readable.
 8889         <p/>
 8890         The wrapper will allow data to be collected on the native
 8891         method call, but now the problem becomes linking up the
 8892         wrapped method with the native implementation.
 8893         That is, the method <code>wrapped_foo</code> needs to be
 8894         resolved to the native implementation of <code>foo</code>,
 8895         which might be:
 8896         <example>
 8897 Java_somePackage_someClass_foo(JNIEnv* env, jint x)</example>
 8898         <p/>
 8899         This function allows the prefix to be specified and the
 8900         proper resolution to occur.
 8901         Specifically, when the standard resolution fails, the
 8902         resolution is retried taking the prefix into consideration.
 8903         There are two ways that resolution occurs, explicit
 8904         resolution with the JNI function <code>RegisterNatives</code>
 8905         and the normal automatic resolution.  For
 8906         <code>RegisterNatives</code>, the VM will attempt this
 8907         association:
 8908         <example>
 8909 method(foo) -> nativeImplementation(foo)</example>
 8910         <p/>
 8911         When this fails, the resolution will be retried with
 8912         the specified prefix prepended to the method name,
 8913         yielding the correct resolution:
 8914         <example>
 8915 method(wrapped_foo) -> nativeImplementation(foo)</example>
 8916         <p/>
 8917         For automatic resolution, the VM will attempt:
 8918         <example>
 8919 method(wrapped_foo) -> nativeImplementation(wrapped_foo)</example>
 8920         <p/>
 8921         When this fails, the resolution will be retried with
 8922         the specified prefix deleted from the implementation name,
 8923         yielding the correct resolution:
 8924         <example>
 8925 method(wrapped_foo) -> nativeImplementation(foo)</example>
 8926         <p/>
 8927         Note that since the prefix is only used when standard
 8928         resolution fails, native methods can be wrapped selectively.
 8929         <p/>
 8930         Since each <jvmti/> environment is independent and
 8931         can do its own transformation of the bytecodes, more
 8932         than one layer of wrappers may be applied. Thus each
 8933         environment needs its own prefix.  Since transformations
 8934         are applied in order, the prefixes, if applied, will
 8935         be applied in the same order.
 8936         The order of transformation application is described in
 8937         the <eventlink id="ClassFileLoadHook"/> event.
 8938         Thus if three environments applied
 8939         wrappers, <code>foo</code> might become
 8940         <code>$env3_$env2_$env1_foo</code>.  But if, say,
 8941         the second environment did not apply a wrapper to
 8942         <code>foo</code> it would be just
 8943         <code>$env3_$env1_foo</code>.  To be able to
 8944         efficiently determine the sequence of prefixes,
 8945         an intermediate prefix is only applied if its non-native
 8946         wrapper exists.  Thus, in the last example, even though
 8947         <code>$env1_foo</code> is not a native method, the
 8948         <code>$env1_</code> prefix is applied since
 8949         <code>$env1_foo</code> exists.
 8950         <p/>
 8951         Since the prefixes are used at resolution time
 8952         and since resolution may be arbitrarily delayed, a
 8953         native method prefix must remain set as long as there
 8954         are corresponding prefixed native methods.
 8955       </description>
 8956       <origin>new</origin>
 8957       <capabilities>
 8958         <required id="can_set_native_method_prefix"></required>
 8959       </capabilities>
 8960       <parameters>
 8961         <param id="prefix">
 8962           <inbuf>
 8963             <char/>
 8964             <nullok>
 8965               any existing prefix in this environment is cancelled
 8966             </nullok>
 8967           </inbuf>
 8968           <description>
 8969             The prefix to apply, encoded as a
 8970             <internallink id="mUTF">modified UTF-8</internallink> string.
 8971           </description>
 8972         </param>
 8973       </parameters>
 8974       <errors>
 8975       </errors>
 8976     </function>
 8977 
 8978     <function id="SetNativeMethodPrefixes" jkernel="yes" phase="any" num="74" since="1.1">
 8979       <synopsis>Set Native Method Prefixes</synopsis>
 8980       <description>
 8981          For a normal agent, <functionlink id="SetNativeMethodPrefix"/>
 8982          will provide all needed native method prefixing.
 8983          For a meta-agent that performs multiple independent class
 8984          file transformations (for example as a proxy for another
 8985          layer of agents) this function allows each transformation
 8986          to have its own prefix.
 8987          The prefixes are applied in the order supplied and are
 8988          processed in the same manner as described for the
 8989          application of prefixes from multiple <jvmti/> environments
 8990          in <functionlink id="SetNativeMethodPrefix"/>.
 8991          <p/>
 8992          Any previous prefixes are replaced.  Thus, calling this
 8993          function with a <paramlink id="prefix_count"/> of <code>0</code>
 8994          disables prefixing in this environment.
 8995          <p/>
 8996          <functionlink id="SetNativeMethodPrefix"/> and this function
 8997          are the two ways to set the prefixes.
 8998          Calling <code>SetNativeMethodPrefix</code> with
 8999          a prefix is the same as calling this function with
 9000          <paramlink id="prefix_count"/> of <code>1</code>.
 9001          Calling <code>SetNativeMethodPrefix</code> with
 9002          <code>NULL</code> is the same as calling this function with
 9003          <paramlink id="prefix_count"/> of <code>0</code>.
 9004       </description>
 9005       <origin>new</origin>
 9006       <capabilities>
 9007         <required id="can_set_native_method_prefix"></required>
 9008       </capabilities>
 9009       <parameters>
 9010         <param id="prefix_count">
 9011           <jint min="0"/>
 9012             <description>
 9013               The number of prefixes to apply.
 9014             </description>
 9015         </param>
 9016         <param id="prefixes">
 9017           <agentbuf>
 9018             <char/>
 9019           </agentbuf>
 9020           <description>
 9021             The prefixes to apply for this environment, each encoded as a
 9022             <internallink id="mUTF">modified UTF-8</internallink> string.
 9023           </description>
 9024         </param>
 9025       </parameters>
 9026       <errors>
 9027       </errors>
 9028     </function>
 9029 
 9030   </category>
 9031 
 9032   <category id="RawMonitors" label="Raw Monitor">
 9033 
 9034     <function id="CreateRawMonitor" phase="onload" callbacksafe="safe" num="31">
 9035       <synopsis>Create Raw Monitor</synopsis>
 9036       <description>
 9037         Create a raw monitor.
 9038       </description>
 9039       <origin>jvmdi</origin>
 9040       <capabilities>
 9041       </capabilities>
 9042       <parameters>
 9043         <param id="name">
 9044           <inbuf><char/></inbuf>
 9045           <description>
 9046             A name to identify the monitor, encoded as a
 9047             <internallink id="mUTF">modified UTF-8</internallink> string.
 9048           </description>
 9049         </param>
 9050         <param id="monitor_ptr">
 9051           <outptr><jrawMonitorID/></outptr>
 9052           <description>
 9053             On return, points to the created monitor.
 9054           </description>
 9055         </param>
 9056       </parameters>
 9057       <errors>
 9058       </errors>
 9059     </function>
 9060 
 9061     <function id="DestroyRawMonitor" phase="onload" callbacksafe="safe" num="32">
 9062       <synopsis>Destroy Raw Monitor</synopsis>
 9063       <description>
 9064         Destroy the raw monitor.
 9065         If the monitor being destroyed has been entered by this thread, it will be
 9066         exited before it is destroyed.
 9067         If the monitor being destroyed has been entered by another thread,
 9068         an error will be returned and the monitor will not be destroyed.
 9069       </description>
 9070       <origin>jvmdi</origin>
 9071       <capabilities>
 9072       </capabilities>
 9073       <parameters>
 9074         <param id="monitor">
 9075           <jrawMonitorID/>
 9076           <description>
 9077             The monitor
 9078           </description>
 9079         </param>
 9080       </parameters>
 9081       <errors>
 9082         <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
 9083           Not monitor owner
 9084         </error>
 9085       </errors>
 9086     </function>
 9087 
 9088     <function id="RawMonitorEnter" phase="any" callbacksafe="safe" impl="innative notrace" num="33">
 9089       <synopsis>Raw Monitor Enter</synopsis>
 9090       <description>
 9091         Gain exclusive ownership of a raw monitor.
 9092         The same thread may enter a monitor more then once.
 9093         The thread must
 9094         <functionlink id="RawMonitorExit">exit</functionlink>
 9095         the monitor the same number of times as it is entered.
 9096         If a monitor is entered during <code>OnLoad</code> (before attached threads exist)
 9097         and has not exited when attached threads come into existence, the enter
 9098         is considered to have occurred on the main thread.
 9099       </description>
 9100       <origin>jvmdi</origin>
 9101       <capabilities>
 9102       </capabilities>
 9103       <parameters>
 9104         <param id="monitor">
 9105           <jrawMonitorID/>
 9106           <description>
 9107             The monitor
 9108           </description>
 9109         </param>
 9110       </parameters>
 9111       <errors>
 9112       </errors>
 9113     </function>
 9114 
 9115     <function id="RawMonitorExit" phase="any" callbacksafe="safe" impl="innative notrace" num="34">
 9116       <synopsis>Raw Monitor Exit</synopsis>
 9117       <description>
 9118         Release exclusive ownership of a raw monitor.
 9119       </description>
 9120       <origin>jvmdi</origin>
 9121       <capabilities>
 9122       </capabilities>
 9123       <parameters>
 9124         <param id="monitor">
 9125           <jrawMonitorID/>
 9126           <description>
 9127             The monitor
 9128           </description>
 9129         </param>
 9130       </parameters>
 9131       <errors>
 9132         <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
 9133           Not monitor owner
 9134         </error>
 9135       </errors>
 9136     </function>
 9137 
 9138     <function id="RawMonitorWait" phase="any" callbacksafe="safe" impl="innative notrace" num="35">
 9139       <synopsis>Raw Monitor Wait</synopsis>
 9140       <description>
 9141         Wait for notification of the raw monitor.
 9142         <p/>
 9143         Causes the current thread to wait until either another thread calls
 9144         <functionlink id="RawMonitorNotify"/> or
 9145         <functionlink id="RawMonitorNotifyAll"/>
 9146         for the specified raw monitor, or the specified
 9147         <paramlink id="millis">timeout</paramlink>
 9148         has elapsed.
 9149       </description>
 9150       <origin>jvmdi</origin>
 9151       <capabilities>
 9152       </capabilities>
 9153       <parameters>
 9154         <param id="monitor">
 9155           <jrawMonitorID/>
 9156           <description>
 9157             The monitor
 9158           </description>
 9159         </param>
 9160         <param id="millis">
 9161           <jlong/>
 9162           <description>
 9163             The timeout, in milliseconds.  If the timeout is
 9164             zero, then real time is not taken into consideration
 9165             and the thread simply waits until notified.
 9166           </description>
 9167         </param>
 9168       </parameters>
 9169       <errors>
 9170         <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
 9171           Not monitor owner
 9172         </error>
 9173         <error id="JVMTI_ERROR_INTERRUPT">
 9174           Wait was interrupted, try again
 9175         </error>
 9176       </errors>
 9177     </function>
 9178 
 9179     <function id="RawMonitorNotify" phase="any" callbacksafe="safe" impl="notrace" num="36">
 9180       <synopsis>Raw Monitor Notify</synopsis>
 9181       <description>
 9182         Notify a single thread waiting on the raw monitor.
 9183       </description>
 9184       <origin>jvmdi</origin>
 9185       <capabilities>
 9186       </capabilities>
 9187       <parameters>
 9188         <param id="monitor">
 9189           <jrawMonitorID/>
 9190           <description>
 9191             The monitor
 9192           </description>
 9193         </param>
 9194       </parameters>
 9195       <errors>
 9196         <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
 9197           Not monitor owner
 9198         </error>
 9199       </errors>
 9200     </function>
 9201 
 9202     <function id="RawMonitorNotifyAll" phase="any" callbacksafe="safe" impl="notrace" num="37">
 9203       <synopsis>Raw Monitor Notify All</synopsis>
 9204       <description>
 9205         Notify all threads waiting on the raw monitor.
 9206       </description>
 9207       <origin>jvmdi</origin>
 9208       <capabilities>
 9209       </capabilities>
 9210       <parameters>
 9211         <param id="monitor">
 9212           <jrawMonitorID/>
 9213           <description>
 9214             The monitor
 9215           </description>
 9216         </param>
 9217       </parameters>
 9218       <errors>
 9219         <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
 9220           Not monitor owner
 9221         </error>
 9222       </errors>
 9223     </function>
 9224 
 9225    <elide>
 9226     <function id="GetRawMonitorUse" num="118">
 9227       <synopsis>Get Raw Monitor Use</synopsis>
 9228       <description>
 9229         The fields of the <functionlink id="jvmtiMonitorUsage"></functionlink> structure
 9230         are filled in with information about usage of the raw monitor.
 9231       </description>
 9232       <origin>new</origin>
 9233       <capabilities>
 9234         <required id="can_get_raw_monitor_usage"></required>
 9235       </capabilities>
 9236       <parameters>
 9237         <param id="monitor">
 9238           <jrawMonitorID/>
 9239           <description>
 9240             the raw monitor to query.
 9241           </description>
 9242         </param>
 9243         <param id="info_ptr">
 9244           <outptr><struct>jvmtiMonitorUsage</struct></outptr>
 9245           <description>
 9246             On return, filled with monitor information for the
 9247             specified raw monitor.
 9248           </description>
 9249         </param>
 9250       </parameters>
 9251       <errors>
 9252       </errors>
 9253     </function>
 9254 
 9255     <function id="GetRawMonitors" num="119">
 9256       <synopsis>Get Raw Monitors</synopsis>
 9257       <description>
 9258         Return the list of raw monitors.
 9259         <p/>
 9260         Note: details about each monitor can be examined with
 9261         <functionlink id="GetRawMonitorUse"></functionlink>.
 9262       </description>
 9263       <origin>new</origin>
 9264       <capabilities>
 9265         <required id="can_get_raw_monitor_usage"></required>
 9266       </capabilities>
 9267       <parameters>
 9268         <param id="monitorCnt">
 9269           <outptr><jint/></outptr>
 9270           <description>
 9271             On return, pointer to the number
 9272             of monitors returned in <code>monitors_ptr</code>.
 9273           </description>
 9274         </param>
 9275         <param id="monitors_ptr">
 9276           <allocbuf outcount="monitorCnt"><jrawMonitorID/></allocbuf>
 9277           <description>
 9278             On return, pointer to the monitor list.
 9279           </description>
 9280         </param>
 9281       </parameters>
 9282       <errors>
 9283       </errors>
 9284     </function>
 9285     </elide>
 9286   </category>
 9287 
 9288   <category id="jniIntercept" label="JNI Function Interception">
 9289 
 9290     <intro>
 9291       Provides the ability to intercept and resend
 9292       Java Native Interface (JNI) function calls
 9293       by manipulating the JNI function table.
 9294       See <externallink id="jni/functions.html">JNI
 9295         Functions</externallink> in the <i>Java Native Interface Specification</i>.
 9296       <p/>
 9297       The following example illustrates intercepting the
 9298       <code>NewGlobalRef</code> JNI call in order to count reference
 9299       creation.
 9300       <example>
 9301 JNIEnv original_jni_Functions;
 9302 JNIEnv redirected_jni_Functions;
 9303 int my_global_ref_count = 0;
 9304 
 9305 jobject
 9306 MyNewGlobalRef(JNIEnv *jni_env, jobject lobj) {
 9307    ++my_global_ref_count;
 9308    return originalJNIFunctions-&gt;NewGlobalRef(env, lobj);
 9309 }
 9310 
 9311 void
 9312 myInit() {
 9313    jvmtiError err;
 9314 
 9315    err = (*jvmti_env)-&gt;GetJNIFunctionTable(jvmti_env, &amp;original_jni_Functions);
 9316    if (err != JVMTI_ERROR_NONE) {
 9317       die();
 9318    }
 9319    err = (*jvmti_env)-&gt;GetJNIFunctionTable(jvmti_env, &amp;redirected_jni_Functions);
 9320    if (err != JVMTI_ERROR_NONE) {
 9321       die();
 9322    }
 9323    redirectedJNIFunctions-&gt;NewGlobalRef = MyNewGlobalRef;
 9324       err = (*jvmti_env)-&gt;SetJNIFunctionTable(jvmti_env, redirected_jni_Functions);
 9325    if (err != JVMTI_ERROR_NONE) {
 9326       die();
 9327    }
 9328 }
 9329       </example>
 9330       Sometime after <code>myInit</code> is called the user's JNI
 9331       code is executed which makes the call to create a new global
 9332       reference.  Instead of going to the normal JNI implementation
 9333       the call goes to <code>myNewGlobalRef</code>.  Note that a
 9334       copy of the original function table is kept so that the normal
 9335       JNI function can be called after the data is collected.
 9336       Note also that any JNI functions which are not overwritten
 9337       will behave normally.
 9338       <todo>
 9339         check that the example compiles and executes.
 9340       </todo>
 9341     </intro>
 9342 
 9343     <function id="SetJNIFunctionTable" phase="start" num="120">
 9344       <synopsis>Set JNI Function Table</synopsis>
 9345       <description>
 9346         Set the JNI function table
 9347         in all current and future JNI environments.
 9348         As a result, all future JNI calls are directed to the specified functions.
 9349         Use <functionlink id="GetJNIFunctionTable"></functionlink> to get the
 9350         function table to pass to this function.
 9351         For this function to take effect the the updated table entries must be
 9352         used by the JNI clients.
 9353         Since the table is defined <code>const</code> some compilers may optimize
 9354         away the access to the table, thus preventing this function from taking
 9355         effect.
 9356         The table is copied--changes to the local copy of the
 9357         table have no effect.
 9358         This function affects only the function table, all other aspects of the environment are
 9359         unaffected.
 9360         See the examples <internallink id="jniIntercept">above</internallink>.
 9361       </description>
 9362       <origin>new</origin>
 9363       <capabilities>
 9364       </capabilities>
 9365       <parameters>
 9366         <param id="function_table">
 9367           <inptr>
 9368             <struct>jniNativeInterface</struct>
 9369           </inptr>
 9370           <description>
 9371             Points to the new JNI function table.
 9372           </description>
 9373         </param>
 9374       </parameters>
 9375       <errors>
 9376       </errors>
 9377     </function>
 9378 
 9379     <function id="GetJNIFunctionTable" phase="start" num="121">
 9380       <synopsis>Get JNI Function Table</synopsis>
 9381       <description>
 9382         Get the JNI function table.
 9383         The JNI function table is copied into allocated memory.
 9384         If <functionlink id="SetJNIFunctionTable"></functionlink>
 9385         has been called, the modified (not the original) function
 9386         table is returned.
 9387         Only the function table is copied, no other aspects of the environment
 9388         are copied.
 9389         See the examples <internallink id="jniIntercept">above</internallink>.
 9390       </description>
 9391       <origin>new</origin>
 9392       <capabilities>
 9393       </capabilities>
 9394       <parameters>
 9395         <param id="function_table">
 9396           <allocbuf>
 9397             <struct>jniNativeInterface</struct>
 9398           </allocbuf>
 9399           <description>
 9400             On return, <code>*function_table</code>
 9401             points a newly allocated copy of the JNI function table.
 9402           </description>
 9403         </param>
 9404       </parameters>
 9405       <errors>
 9406       </errors>
 9407     </function>
 9408 
 9409   </category>
 9410 
 9411   <category id="eventManagement" label="Event Management">
 9412 
 9413     <function id="SetEventCallbacks" jkernel="yes" phase="onload" num="122">
 9414       <synopsis>Set Event Callbacks</synopsis>
 9415       <description>
 9416         Set the functions to be called for each event.
 9417         The callbacks are specified by supplying a replacement function table.
 9418         The function table is copied--changes to the local copy of the
 9419         table have no effect.
 9420         This is an atomic action, all callbacks are set at once.
 9421         No events are sent before this function is called.
 9422         When an entry is <code>NULL</code> or when the event is beyond
 9423         <paramlink id="size_of_callbacks"></paramlink> no event is sent.
 9424         Details on events are
 9425         described <internallink id="EventSection">later</internallink> in this document.
 9426         An event must be enabled and have a callback in order to be
 9427         sent--the order in which this function and
 9428         <functionlink id="SetEventNotificationMode"></functionlink>
 9429         are called does not affect the result.
 9430       </description>
 9431       <origin>new</origin>
 9432       <capabilities>
 9433       </capabilities>
 9434       <parameters>
 9435         <param id="callbacks">
 9436           <inptr>
 9437             <struct>jvmtiEventCallbacks</struct>
 9438             <nullok>remove the existing callbacks</nullok>
 9439           </inptr>
 9440           <description>
 9441             The new event callbacks.
 9442           </description>
 9443         </param>
 9444         <param id="size_of_callbacks">
 9445           <jint min="0"/>
 9446           <description>
 9447             <code>sizeof(jvmtiEventCallbacks)</code>--for version
 9448             compatibility.
 9449           </description>
 9450         </param>
 9451       </parameters>
 9452       <errors>
 9453       </errors>
 9454     </function>
 9455 
 9456     <function id="SetEventNotificationMode" jkernel="yes" phase="onload" num="2">
 9457       <synopsis>Set Event Notification Mode</synopsis>
 9458       <description>
 9459         Control the generation of events.
 9460         <constants id="jvmtiEventMode" label="Event Enable/Disable" kind="enum">
 9461           <constant id="JVMTI_ENABLE" num="1">
 9462             If <paramlink id="mode"></paramlink> is <code>JVMTI_ENABLE</code>,
 9463             the event <paramlink id="event_type"></paramlink> will be enabled
 9464           </constant>
 9465           <constant id="JVMTI_DISABLE" num="0">
 9466             If <paramlink id="mode"></paramlink> is <code>JVMTI_DISABLE</code>,
 9467             the event <paramlink id="event_type"></paramlink> will be disabled
 9468           </constant>
 9469         </constants>
 9470         If <code>event_thread</code> is <code>NULL</code>,
 9471         the event is enabled or disabled globally; otherwise, it is
 9472         enabled or disabled for a particular thread.
 9473         An event is generated for
 9474         a particular thread if it is enabled either at the thread or global
 9475         levels.
 9476         <p/>
 9477         See <internallink id="EventIndex">below</internallink> for information on specific events.
 9478         <p/>
 9479         The following events cannot be controlled at the thread
 9480         level through this function.
 9481         <ul>
 9482           <li><eventlink id="VMInit"></eventlink></li>
 9483           <li><eventlink id="VMStart"></eventlink></li>
 9484           <li><eventlink id="VMDeath"></eventlink></li>
 9485           <li><eventlink id="ThreadStart"></eventlink></li>
 9486           <li><eventlink id="CompiledMethodLoad"></eventlink></li>
 9487           <li><eventlink id="CompiledMethodUnload"></eventlink></li>
 9488           <li><eventlink id="DynamicCodeGenerated"></eventlink></li>
 9489           <li><eventlink id="DataDumpRequest"></eventlink></li>
 9490         </ul>
 9491         <p/>
 9492         Initially, no events are enabled at either the thread level
 9493         or the global level.
 9494         <p/>
 9495         Any needed capabilities (see Event Enabling Capabilities below) must be possessed
 9496         before calling this function.
 9497         <p/>
 9498         Details on events are
 9499         described <internallink id="EventSection">below</internallink>.
 9500       </description>
 9501       <origin>jvmdiClone</origin>
 9502       <eventcapabilities></eventcapabilities>
 9503       <parameters>
 9504         <param id="mode">
 9505           <enum>jvmtiEventMode</enum>
 9506           <description>
 9507             <code>JVMTI_ENABLE</code> or <code>JVMTI_DISABLE</code>
 9508           </description>
 9509         </param>
 9510         <param id="event_type">
 9511           <enum>jvmtiEvent</enum>
 9512           <description>
 9513             the event to control
 9514           </description>
 9515         </param>
 9516         <param id="event_thread">
 9517           <ptrtype>
 9518             <jthread impl="noconvert"/>
 9519             <nullok>event is controlled at the global level</nullok>
 9520           </ptrtype>
 9521             <description>
 9522               The thread to control
 9523             </description>
 9524         </param>
 9525         <param id="...">
 9526           <varargs/>
 9527             <description>
 9528               for future expansion
 9529             </description>
 9530         </param>
 9531       </parameters>
 9532       <errors>
 9533         <error id="JVMTI_ERROR_INVALID_THREAD">
 9534           <paramlink id="event_thread"/> is non-<code>NULL</code> and is not a valid thread.
 9535         </error>
 9536         <error id="JVMTI_ERROR_THREAD_NOT_ALIVE">
 9537           <paramlink id="event_thread"/> is non-<code>NULL</code> and is not live (has not been started or is now dead).
 9538         </error>
 9539         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
 9540           thread level control was attempted on events which do not
 9541           permit thread level control.
 9542         </error>
 9543         <error id="JVMTI_ERROR_MUST_POSSESS_CAPABILITY">
 9544           The Required Event Enabling Capability is not possessed.
 9545         </error>
 9546       </errors>
 9547     </function>
 9548 
 9549     <function id="GenerateEvents" num="123">
 9550       <synopsis>Generate Events</synopsis>
 9551       <description>
 9552         Generate events to represent the current state of the VM.
 9553         For example, if <paramlink id="event_type"/> is
 9554         <code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code>,
 9555         a <eventlink id="CompiledMethodLoad"></eventlink> event will be
 9556         sent for each currently compiled method.
 9557         Methods that were loaded and now have been unloaded are not sent.
 9558         The history of what events have previously been sent does not
 9559         effect what events are sent by this function--for example,
 9560         all currently compiled methods
 9561         will be sent each time this function is called.
 9562         <p/>
 9563         This function is useful when
 9564         events may have been missed due to the agent attaching after program
 9565         execution begins; this function generates the missed events.
 9566         <p/>
 9567         Attempts to execute Java programming language code or
 9568         JNI functions may be paused until this function returns -
 9569         so neither should be called from the thread sending the event.
 9570         This function returns only after the missed events have been
 9571         sent, processed and have returned.
 9572         The event may be sent on a different thread than the thread
 9573         on which the event occurred.
 9574         The callback for the event must be set with
 9575         <functionlink id="SetEventCallbacks"></functionlink>
 9576         and the event must be enabled with
 9577         <functionlink id="SetEventNotificationMode"></functionlink>
 9578         or the events will not occur.
 9579         If the VM no longer has the information to generate some or
 9580         all of the requested events, the events are simply not sent -
 9581         no error is returned.
 9582         <p/>
 9583         Only the following events are supported:
 9584         <ul>
 9585           <li><eventlink id="CompiledMethodLoad"></eventlink></li>
 9586           <li><eventlink id="DynamicCodeGenerated"></eventlink></li>
 9587         </ul>
 9588       </description>
 9589       <origin>new</origin>
 9590       <capabilities>
 9591         <capability id="can_generate_compiled_method_load_events"></capability>
 9592       </capabilities>
 9593       <parameters>
 9594         <param id="event_type">
 9595           <enum>jvmtiEvent</enum>
 9596           <description>
 9597             The type of event to generate.  Must be one of these:
 9598             <ul>
 9599               <li><eventlink id="CompiledMethodLoad"><code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code></eventlink></li>
 9600               <li><eventlink id="DynamicCodeGenerated"><code>JVMTI_EVENT_DYNAMIC_CODE_GENERATED</code></eventlink></li>
 9601             </ul>
 9602           </description>
 9603         </param>
 9604       </parameters>
 9605       <errors>
 9606         <error id="JVMTI_ERROR_MUST_POSSESS_CAPABILITY">
 9607           <paramlink id="event_type"/> is
 9608           <eventlink id="CompiledMethodLoad"><code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code></eventlink>
 9609           and <fieldlink id="can_generate_compiled_method_load_events" struct="jvmtiCapabilities"></fieldlink>
 9610           is <code>false</code>.
 9611         </error>
 9612         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
 9613           <paramlink id="event_type"/> is other than
 9614           <eventlink id="CompiledMethodLoad"><code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code></eventlink>
 9615           or <eventlink id="DynamicCodeGenerated"><code>JVMTI_EVENT_DYNAMIC_CODE_GENERATED</code></eventlink>.
 9616         </error>
 9617       </errors>
 9618     </function>
 9619 
 9620   </category>
 9621 
 9622     <category id="extension" label="Extension Mechanism">
 9623 
 9624       <intro>
 9625         These functions
 9626         allow a <jvmti/> implementation to provide functions and events
 9627         beyond those defined in this specification.
 9628         <p/>
 9629         Both extension functions and extension events have parameters
 9630         each of which has a 'type' and 'kind' chosen from the following tables:
 9631 
 9632         <constants id="jvmtiParamTypes" label="Extension Function/Event Parameter Types" kind="enum">
 9633           <constant id="JVMTI_TYPE_JBYTE" num="101">
 9634             Java programming language primitive type - <code>byte</code>.
 9635             JNI type <code>jbyte</code>.
 9636           </constant>
 9637           <constant id="JVMTI_TYPE_JCHAR" num="102">
 9638             Java programming language primitive type - <code>char</code>.
 9639             JNI type <code>jchar</code>.
 9640           </constant>
 9641           <constant id="JVMTI_TYPE_JSHORT" num="103">
 9642             Java programming language primitive type - <code>short</code>.
 9643             JNI type <code>jshort</code>.
 9644           </constant>
 9645           <constant id="JVMTI_TYPE_JINT" num="104">
 9646             Java programming language primitive type - <code>int</code>.
 9647             JNI type <datalink id="jint"></datalink>.
 9648           </constant>
 9649           <constant id="JVMTI_TYPE_JLONG" num="105">
 9650             Java programming language primitive type - <code>long</code>.
 9651             JNI type <datalink id="jlong"></datalink>.
 9652           </constant>
 9653           <constant id="JVMTI_TYPE_JFLOAT" num="106">
 9654             Java programming language primitive type - <code>float</code>.
 9655             JNI type <datalink id="jfloat"></datalink>.
 9656           </constant>
 9657           <constant id="JVMTI_TYPE_JDOUBLE" num="107">
 9658             Java programming language primitive type - <code>double</code>.
 9659             JNI type <datalink id="jdouble"></datalink>.
 9660           </constant>
 9661           <constant id="JVMTI_TYPE_JBOOLEAN" num="108">
 9662             Java programming language primitive type - <code>boolean</code>.
 9663             JNI type <datalink id="jboolean"></datalink>.
 9664           </constant>
 9665           <constant id="JVMTI_TYPE_JOBJECT" num="109">
 9666             Java programming language object type - <code>java.lang.Object</code>.
 9667             JNI type <datalink id="jobject"></datalink>.
 9668             Returned values are JNI local references and must be managed.
 9669           </constant>
 9670           <constant id="JVMTI_TYPE_JTHREAD" num="110">
 9671             Java programming language object type - <code>java.lang.Thread</code>.
 9672             <jvmti/> type <datalink id="jthread"></datalink>.
 9673             Returned values are JNI local references and must be managed.
 9674           </constant>
 9675           <constant id="JVMTI_TYPE_JCLASS" num="111">
 9676             Java programming language object type - <code>java.lang.Class</code>.
 9677             JNI type <datalink id="jclass"></datalink>.
 9678             Returned values are JNI local references and must be managed.
 9679           </constant>
 9680           <constant id="JVMTI_TYPE_JVALUE" num="112">
 9681             Union of all Java programming language primitive and object types -
 9682             JNI type <datalink id="jvalue"></datalink>.
 9683             Returned values which represent object types are JNI local references and must be managed.
 9684           </constant>
 9685           <constant id="JVMTI_TYPE_JFIELDID" num="113">
 9686             Java programming language field identifier -
 9687             JNI type <datalink id="jfieldID"></datalink>.
 9688           </constant>
 9689           <constant id="JVMTI_TYPE_JMETHODID" num="114">
 9690             Java programming language method identifier -
 9691             JNI type <datalink id="jmethodID"></datalink>.
 9692           </constant>
 9693           <constant id="JVMTI_TYPE_CCHAR" num="115">
 9694             C programming language type - <code>char</code>.
 9695           </constant>
 9696           <constant id="JVMTI_TYPE_CVOID" num="116">
 9697             C programming language type - <code>void</code>.
 9698           </constant>
 9699           <constant id="JVMTI_TYPE_JNIENV" num="117">
 9700             JNI environment - <code>JNIEnv</code>.
 9701             Should be used with the correct <datalink id="jvmtiParamKind"/> to make it a pointer type.
 9702           </constant>
 9703         </constants>
 9704 
 9705         <constants id="jvmtiParamKind" label="Extension Function/Event Parameter Kinds" kind="enum">
 9706           <constant id="JVMTI_KIND_IN" num="91">
 9707             Ingoing argument - <code>foo</code>.
 9708           </constant>
 9709           <constant id="JVMTI_KIND_IN_PTR" num="92">
 9710             Ingoing pointer argument - <code>const foo*</code>.
 9711           </constant>
 9712           <constant id="JVMTI_KIND_IN_BUF" num="93">
 9713             Ingoing array argument - <code>const foo*</code>.
 9714           </constant>
 9715           <constant id="JVMTI_KIND_ALLOC_BUF" num="94">
 9716             Outgoing allocated array argument -  <code>foo**</code>.
 9717             Free with <code>Deallocate</code>.
 9718           </constant>
 9719           <constant id="JVMTI_KIND_ALLOC_ALLOC_BUF" num="95">
 9720             Outgoing allocated array of allocated arrays argument - <code>foo***</code>.
 9721             Free with <code>Deallocate</code>.
 9722           </constant>
 9723           <constant id="JVMTI_KIND_OUT" num="96">
 9724             Outgoing argument - <code>foo*</code>.
 9725           </constant>
 9726           <constant id="JVMTI_KIND_OUT_BUF" num="97">
 9727             Outgoing array argument (pre-allocated by agent) - <code>foo*</code>.
 9728             Do not <code>Deallocate</code>.
 9729           </constant>
 9730         </constants>
 9731 
 9732       </intro>
 9733 
 9734       <typedef id="jvmtiParamInfo" label="Extension Function/Event Parameter Info">
 9735         <field id="name">
 9736           <allocfieldbuf><char/></allocfieldbuf>
 9737             <description>
 9738               The parameter name, encoded as a
 9739               <internallink id="mUTF">modified UTF-8</internallink> string
 9740             </description>
 9741         </field>
 9742         <field id="kind">
 9743           <enum>jvmtiParamKind</enum>
 9744           <description>
 9745             The kind of the parameter - type modifiers
 9746           </description>
 9747         </field>
 9748         <field id="base_type">
 9749           <enum>jvmtiParamTypes</enum>
 9750           <description>
 9751             The base type of the parameter -  modified by <code>kind</code>
 9752           </description>
 9753         </field>
 9754         <field id="null_ok">
 9755           <jboolean/>
 9756             <description>
 9757               Is a <code>NULL</code> argument permitted? Applies only to pointer and object types.
 9758             </description>
 9759         </field>
 9760       </typedef>
 9761 
 9762       <callback id="jvmtiExtensionFunction">
 9763         <enum>jvmtiError</enum>
 9764           <synopsis>Extension Function</synopsis>
 9765         <description>
 9766           This is the implementation-specific extension function.
 9767         </description>
 9768         <parameters>
 9769           <param id="jvmti_env">
 9770             <outptr>
 9771               <struct>jvmtiEnv</struct>
 9772             </outptr>
 9773             <description>
 9774               The <jvmti/> environment is the only fixed parameter for extension functions.
 9775             </description>
 9776           </param>
 9777           <param id="...">
 9778             <varargs/>
 9779               <description>
 9780                 The extension function-specific parameters
 9781               </description>
 9782           </param>
 9783         </parameters>
 9784       </callback>
 9785 
 9786       <function id="GetExtensionFunctions" phase="onload" num="124">
 9787         <synopsis>Get Extension Functions</synopsis>
 9788 
 9789         <typedef id="jvmtiExtensionFunctionInfo" label="Extension Function Info">
 9790           <field id="func">
 9791             <ptrtype>
 9792               <struct>jvmtiExtensionFunction</struct>
 9793             </ptrtype>
 9794             <description>
 9795               The actual function to call
 9796             </description>
 9797           </field>
 9798           <field id="id">
 9799             <allocfieldbuf><char/></allocfieldbuf>
 9800               <description>
 9801                 The identifier for the extension function, encoded as a
 9802                 <internallink id="mUTF">modified UTF-8</internallink> string.
 9803                 Uses package name conventions.
 9804                 For example, <code>com.sun.hotspot.bar</code>
 9805               </description>
 9806           </field>
 9807           <field id="short_description">
 9808             <allocfieldbuf><char/></allocfieldbuf>
 9809               <description>
 9810                 A one sentence description of the function, encoded as a
 9811                 <internallink id="mUTF">modified UTF-8</internallink> string.
 9812               </description>
 9813           </field>
 9814           <field id="param_count">
 9815             <jint/>
 9816               <description>
 9817                 The number of parameters excluding <code>jvmtiEnv *jvmti_env</code>
 9818               </description>
 9819           </field>
 9820           <field id="params">
 9821             <allocfieldbuf outcount="param_count">
 9822               <struct>jvmtiParamInfo</struct>
 9823             </allocfieldbuf>
 9824             <description>
 9825               Array of
 9826               <fieldlink id="param_count" struct="jvmtiExtensionFunctionInfo"></fieldlink>
 9827               parameters (<code>jvmtiEnv *jvmti_env</code> excluded)
 9828             </description>
 9829           </field>
 9830           <field id="error_count">
 9831             <jint/>
 9832               <description>
 9833                 The number of possible error returns (excluding universal errors)
 9834               </description>
 9835           </field>
 9836           <field id="errors">
 9837             <allocfieldbuf outcount="error_count">
 9838               <enum>jvmtiError</enum>
 9839             </allocfieldbuf>
 9840             <description>
 9841               Array of <fieldlink id="error_count" struct="jvmtiExtensionFunctionInfo"></fieldlink>
 9842               possible errors
 9843             </description>
 9844           </field>
 9845         </typedef>
 9846 
 9847         <description>
 9848           Returns the set of extension functions.
 9849         </description>
 9850         <origin>new</origin>
 9851         <capabilities>
 9852         </capabilities>
 9853         <parameters>
 9854           <param id="extension_count_ptr">
 9855             <outptr><jint/></outptr>
 9856               <description>
 9857                 On return, points to the number of extension functions
 9858               </description>
 9859           </param>
 9860           <param id="extensions">
 9861             <allocbuf outcount="extension_count_ptr"><struct>jvmtiExtensionFunctionInfo</struct></allocbuf>
 9862             <description>
 9863               Returns an array of extension function info, one per function
 9864             </description>
 9865           </param>
 9866         </parameters>
 9867         <errors>
 9868         </errors>
 9869       </function>
 9870 
 9871       <function id="GetExtensionEvents" phase="onload" num="125">
 9872         <synopsis>Get Extension Events</synopsis>
 9873 
 9874         <typedef id="jvmtiExtensionEventInfo" label="Extension Event Info">
 9875           <field id="extension_event_index">
 9876             <jint/>
 9877             <description>
 9878               The identifying index of the event
 9879             </description>
 9880           </field>
 9881           <field id="id">
 9882             <allocfieldbuf><char/></allocfieldbuf>
 9883               <description>
 9884                 The identifier for the extension event, encoded as a
 9885                 <internallink id="mUTF">modified UTF-8</internallink> string.
 9886                 Uses package name conventions.
 9887                 For example, <code>com.sun.hotspot.bar</code>
 9888               </description>
 9889           </field>
 9890           <field id="short_description">
 9891             <allocfieldbuf><char/></allocfieldbuf>
 9892               <description>
 9893                 A one sentence description of the event, encoded as a
 9894                 <internallink id="mUTF">modified UTF-8</internallink> string.
 9895               </description>
 9896           </field>
 9897           <field id="param_count">
 9898             <jint/>
 9899               <description>
 9900                 The number of parameters excluding <code>jvmtiEnv *jvmti_env</code>
 9901               </description>
 9902           </field>
 9903           <field id="params">
 9904             <allocfieldbuf outcount="param_count">
 9905               <struct>jvmtiParamInfo</struct>
 9906             </allocfieldbuf>
 9907             <description>
 9908               Array of
 9909               <fieldlink id="param_count" struct="jvmtiExtensionEventInfo"></fieldlink>
 9910               parameters (<code>jvmtiEnv *jvmti_env</code> excluded)
 9911             </description>
 9912           </field>
 9913         </typedef>
 9914 
 9915         <description>
 9916           Returns the set of extension events.
 9917         </description>
 9918         <origin>new</origin>
 9919         <capabilities>
 9920         </capabilities>
 9921         <parameters>
 9922           <param id="extension_count_ptr">
 9923             <outptr><jint/></outptr>
 9924               <description>
 9925                 On return, points to the number of extension events
 9926               </description>
 9927           </param>
 9928           <param id="extensions">
 9929             <allocbuf outcount="extension_count_ptr"><struct>jvmtiExtensionEventInfo</struct></allocbuf>
 9930             <description>
 9931               Returns an array of extension event info, one per event
 9932             </description>
 9933           </param>
 9934         </parameters>
 9935         <errors>
 9936         </errors>
 9937       </function>
 9938 
 9939       <callback id="jvmtiExtensionEvent">
 9940         <void/>
 9941           <synopsis>Extension Event</synopsis>
 9942         <description>
 9943           This is the implementation-specific event.
 9944           The event handler is set with
 9945           <functionlink id="SetExtensionEventCallback"/>.
 9946           <p/>
 9947           Event handlers for extension events must be declared varargs to match this definition.
 9948           Failure to do so could result in calling convention mismatch and undefined behavior
 9949           on some platforms.
 9950           <p/>
 9951           For example, if the <code>jvmtiParamInfo</code>
 9952           returned by <functionlink id="GetExtensionEvents"/> indicates that
 9953           there is a <code>jint</code> parameter, the event handler should be
 9954           declared:
 9955 <example>
 9956     void JNICALL myHandler(jvmtiEnv* jvmti_env, ...)
 9957 </example>
 9958           Note the terminal "<code>...</code>" which indicates varargs.
 9959           The <code>jint</code> argument inside <code>myHandler</code> needs to be extracted using
 9960           the <code>va_*</code> syntax of the C programming language.
 9961         </description>
 9962         <parameters>
 9963           <param id="jvmti_env">
 9964             <outptr>
 9965               <struct>jvmtiEnv</struct>
 9966             </outptr>
 9967             <description>
 9968               The <jvmti/> environment is the only fixed parameter for extension events.
 9969             </description>
 9970           </param>
 9971           <param id="...">
 9972             <varargs/>
 9973               <description>
 9974                 The extension event-specific parameters
 9975               </description>
 9976           </param>
 9977         </parameters>
 9978       </callback>
 9979 
 9980       <function id="SetExtensionEventCallback" phase="onload" num="126">
 9981         <synopsis>Set Extension Event Callback</synopsis>
 9982 
 9983         <description>
 9984           Sets the callback function for an extension event and
 9985           enables the event. Or, if the callback is <code>NULL</code>, disables
 9986           the event.  Note that unlike standard events, setting
 9987           the callback and enabling the event are a single operation.
 9988         </description>
 9989         <origin>new</origin>
 9990         <capabilities>
 9991         </capabilities>
 9992         <parameters>
 9993           <param id="extension_event_index">
 9994             <jint/>
 9995               <description>
 9996                 Identifies which callback to set.
 9997                 This index is the
 9998                 <fieldlink id="extension_event_index" struct="jvmtiExtensionEventInfo"></fieldlink>
 9999                 field of
10000                 <datalink id="jvmtiExtensionEventInfo"/>.
10001               </description>
10002           </param>
10003           <param id="callback">
10004             <ptrtype>
10005               <struct>jvmtiExtensionEvent</struct>
10006               <nullok>disable the event</nullok>
10007             </ptrtype>
10008             <description>
10009               If <code>callback</code> is non-<code>NULL</code>,
10010               set <code>callback</code> to be the event callback function
10011               and enable the event.
10012             </description>
10013           </param>
10014         </parameters>
10015         <errors>
10016         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
10017             <paramlink id="extension_event_index"/> is not an
10018             <fieldlink id="extension_event_index"
10019                        struct="jvmtiExtensionEventInfo"/>
10020             returned by
10021             <functionlink id="GetExtensionEvents"/>
10022         </error>
10023         </errors>
10024       </function>
10025 
10026     </category>
10027 
10028   <category id="capability" label="Capability">
10029 
10030     <intro>
10031       The capabilities functions allow you to change the
10032       functionality available to <jvmti/>--that is,
10033       which <jvmti/>
10034       functions can be called, what events can be generated,
10035       and what functionality these events and functions can
10036       provide.
10037       <p/>
10038         The "Capabilities" section of each function and event describe which
10039         capabilities, if any, they are associated with. "Required Functionality"
10040         means it is available for use and no capabilities must be added to use it.
10041         "Optional Functionality" means the agent must possess the capability
10042         before it can be used.
10043         To possess a capability, the agent must
10044         <functionlink id="AddCapabilities">add the capability</functionlink>.
10045         "Optional Features" describe capabilities which,
10046         if added, extend the feature set.
10047         <p/>
10048         The potentially available capabilities of each <jvmti/> implementation are different.
10049         Depending on the implementation, a capability:
10050         <ul>
10051           <li>may never be added</li>
10052           <li>may be added in either the <code>OnLoad</code> or live phase in any environment</li>
10053           <li>may be added only during the <code>OnLoad</code> phase</li>
10054           <li>may be possessed by only one environment at a time</li>
10055           <li>may be possessed by only one environment at a time,
10056               and only during the <code>OnLoad</code> phase</li>
10057           <li>and so on ...</li>
10058         </ul>
10059       Frequently, the addition of a capability may incur a cost in execution speed, start up
10060       time, and/or memory footprint.  Note that the overhead of using a capability
10061       is completely different than the overhead of possessing a capability.
10062       Take single stepping as an example. When single stepping is on (that
10063       is, when the event is enabled and thus actively sending events)
10064       the overhead of sending and processing an event
10065       on each instruction is huge in any implementation.
10066       However, the overhead of possessing the capability may be small or large,
10067       depending on the implementation.  Also, when and if a capability is potentially
10068       available depends on the implementation.  Some examples:
10069       <ul>
10070         <li>One VM might perform all execution by compiling bytecodes into
10071           native code and be unable to generate single step instructions.
10072           In this implementation the capability can not be added.</li>
10073         <li>Another VM may be able to switch execution to a single stepping
10074           interpreter at any time.  In this implementation, having the capability has no
10075           overhead and could be added at any time.</li>
10076         <li>Yet another VM might be able to choose a bytecode compiling or single stepping capable interpreted
10077           execution engine at start up, but be unable to switch between them.
10078           In this implementation the capability would need to be added
10079           during the <code>OnLoad</code> phase (before bytecode
10080           execution begins) and would have a large impact on execution speed
10081           even if single stepping was never used.</li>
10082         <li>Still another VM might be able to add an "is single stepping on" check
10083           into compiled bytecodes or a generated interpreter.  Again in this implementation
10084           the capability would need to be added during the <code>OnLoad</code> phase but the overhead (a test
10085           and branch on each instruction) would be considerably less.</li>
10086       </ul>
10087       <p/>
10088       Each <jvmti/> <internallink id="environments">environment</internallink>
10089       has its own set of capabilities.
10090       Initially, that set is empty.
10091       Any desired capability must be added.
10092       If possible, capabilities should be added during the <code>OnLoad</code> phase.  For most
10093       virtual machines certain capabilities require special set up for
10094       the virtual machine and this set up must happen
10095       during the <code>OnLoad</code> phase, before the virtual machine begins execution.
10096       Once a capability is added, it can
10097       only be removed if explicitly relinquished by the environment.
10098       <p/>
10099       The agent can,
10100       <functionlink id="GetPotentialCapabilities">determine what
10101         capabilities this VM can potentially provide</functionlink>,
10102       <functionlink id="AddCapabilities">add the capabilities
10103         to be used</functionlink>,
10104       <functionlink id="RelinquishCapabilities">release capabilities
10105         which are no longer needed</functionlink>, and
10106       <functionlink id="GetCapabilities">examine the currently available
10107         capabilities</functionlink>.
10108     </intro>
10109 
10110     <intro id="capabilityExamples" label="Capability Examples">
10111       For example, a freshly started agent (in the <code>OnLoad</code> function)
10112       wants to enable all possible capabilities.
10113       Note that, in general, this is not advisable as the agent may suffer
10114       a performance penalty for functionality it is not using.
10115       The code might look like this in C:
10116       <example>
10117         jvmtiCapabilities capa;
10118         jvmtiError err;
10119 
10120         err = (*jvmti)-&gt;GetPotentialCapabilities(jvmti, &amp;capa);
10121         if (err == JVMTI_ERROR_NONE) {
10122            err = (*jvmti)-&gt;AddCapabilities(jvmti, &amp;capa);
10123       </example>
10124       For example, if an  agent wants to check if it can get
10125       the bytecodes of a method (that is, it wants to check
10126       if it previously added this capability and has not
10127       relinquished it), the code might
10128       look like this in C:
10129       <example>
10130         jvmtiCapabilities capa;
10131         jvmtiError err;
10132 
10133         err = (*jvmti)-&gt;GetCapabilities(jvmti, &amp;capa);
10134         if (err == JVMTI_ERROR_NONE) {
10135            if (capa.can_get_bytecodes) { ... } }
10136       </example>
10137     </intro>
10138 
10139     <capabilitiestypedef id="jvmtiCapabilities" label="The Capabilities Structure">
10140       <description>
10141         The functions in this category use this capabilities structure
10142         which contains boolean flags corresponding to each capability:
10143       </description>
10144       <capabilityfield id="can_tag_objects">
10145         <description>
10146           Can set and get tags, as described in the
10147           <internallink id="Heap">Heap category</internallink>.
10148         </description>
10149       </capabilityfield>
10150       <capabilityfield id="can_generate_field_modification_events">
10151         <description>
10152           Can set watchpoints on field modification -
10153           <functionlink id="SetFieldModificationWatch"></functionlink>
10154         </description>
10155       </capabilityfield>
10156       <capabilityfield id="can_generate_field_access_events">
10157         <description>
10158           Can set watchpoints on field access -
10159           <functionlink id="SetFieldAccessWatch"></functionlink>
10160         </description>
10161       </capabilityfield>
10162       <capabilityfield id="can_get_bytecodes">
10163         <description>
10164           Can get bytecodes of a method <functionlink id="GetBytecodes"></functionlink>
10165         </description>
10166       </capabilityfield>
10167       <capabilityfield id="can_get_synthetic_attribute">
10168         <description>
10169           Can test if a field or method is synthetic -
10170           <functionlink id="IsFieldSynthetic"></functionlink> and
10171           <functionlink id="IsMethodSynthetic"></functionlink>
10172         </description>
10173       </capabilityfield>
10174       <capabilityfield id="can_get_owned_monitor_info">
10175         <description>
10176           Can get information about ownership of monitors -
10177           <functionlink id="GetOwnedMonitorInfo"></functionlink>
10178         </description>
10179       </capabilityfield>
10180       <capabilityfield id="can_get_current_contended_monitor">
10181         <description>
10182           Can <functionlink id="GetCurrentContendedMonitor"></functionlink>
10183         </description>
10184       </capabilityfield>
10185       <capabilityfield id="can_get_monitor_info">
10186       <description>
10187         Can <functionlink id="GetObjectMonitorUsage"></functionlink>
10188       </description>
10189       </capabilityfield>
10190       <capabilityfield id="can_pop_frame">
10191         <description>
10192           Can pop frames off the stack - <functionlink id="PopFrame"></functionlink>
10193         </description>
10194       </capabilityfield>
10195       <capabilityfield id="can_redefine_classes">
10196         <description>
10197           Can redefine classes with <functionlink id="RedefineClasses"/>.
10198         </description>
10199       </capabilityfield>
10200       <capabilityfield id="can_signal_thread">
10201         <description>
10202           Can send stop or interrupt to threads
10203         </description>
10204       </capabilityfield>
10205       <capabilityfield id="can_get_source_file_name">
10206         <description>
10207           Can get the source file name of a class
10208         </description>
10209       </capabilityfield>
10210       <capabilityfield id="can_get_line_numbers">
10211         <description>
10212           Can get the line number table of a method
10213         </description>
10214       </capabilityfield>
10215       <capabilityfield id="can_get_source_debug_extension">
10216         <description>
10217           Can get the source debug extension of a class
10218         </description>
10219       </capabilityfield>
10220       <capabilityfield id="can_access_local_variables">
10221         <description>
10222           Can set and get local variables
10223         </description>
10224       </capabilityfield>
10225       <capabilityfield id="can_maintain_original_method_order">
10226         <description>
10227           Can return methods in the order they occur in the class file
10228         </description>
10229       </capabilityfield>
10230       <capabilityfield id="can_generate_single_step_events">
10231         <description>
10232           Can get <eventlink id="SingleStep">single step</eventlink> events
10233         </description>
10234       </capabilityfield>
10235       <capabilityfield id="can_generate_exception_events">
10236         <description>
10237           Can get <eventlink id="Exception">exception thrown</eventlink> and
10238             <eventlink id="ExceptionCatch">exception catch</eventlink> events
10239         </description>
10240       </capabilityfield>
10241       <capabilityfield id="can_generate_frame_pop_events">
10242         <description>
10243           Can <functionlink id="NotifyFramePop">set</functionlink> and thus get
10244             <eventlink id="FramePop"></eventlink> events
10245         </description>
10246       </capabilityfield>
10247       <capabilityfield id="can_generate_breakpoint_events">
10248         <description>
10249           Can <functionlink id="SetBreakpoint">set</functionlink> and thus get
10250             <eventlink id="Breakpoint"></eventlink> events
10251         </description>
10252       </capabilityfield>
10253       <capabilityfield id="can_suspend">
10254         <description>
10255           Can suspend and resume threads
10256         </description>
10257       </capabilityfield>
10258       <capabilityfield id="can_redefine_any_class">
10259         <description>
10260           <functionlink id="RedefineClasses"/> can be called on any modifiable class.
10261           See <functionlink id="IsModifiableClass"/>.
10262           (<fieldlink id="can_redefine_classes" struct="jvmtiCapabilities"/>
10263           must also be set)
10264         </description>
10265       </capabilityfield>
10266       <capabilityfield id="can_get_current_thread_cpu_time">
10267         <description>
10268           Can <functionlink id="GetCurrentThreadCpuTime">get</functionlink>
10269           current thread CPU time
10270         </description>
10271       </capabilityfield>
10272       <capabilityfield id="can_get_thread_cpu_time">
10273         <description>
10274           Can <functionlink id="GetThreadCpuTime">get</functionlink>
10275           thread CPU time
10276         </description>
10277       </capabilityfield>
10278       <capabilityfield id="can_generate_method_entry_events"
10279                        disp1="can_generate" disp2="_method_entry_events"
10280                        >
10281         <description>
10282           Can generate method entry events on entering a method
10283         </description>
10284       </capabilityfield>
10285       <capabilityfield id="can_generate_method_exit_events"
10286                        disp1="can_generate" disp2="_method_exit_events"
10287                        >
10288         <description>
10289           Can generate method exit events on leaving a method
10290         </description>
10291       </capabilityfield>
10292       <capabilityfield id="can_generate_all_class_hook_events"
10293                        disp1="can_generate" disp2="_all_class_hook_events"
10294                        >
10295         <description>
10296           Can generate ClassFileLoadHook events for every loaded class.
10297         </description>
10298       </capabilityfield>
10299       <capabilityfield id="can_generate_compiled_method_load_events"
10300                        disp1="can_generate" disp2="_compiled_method_load_events"
10301                        >
10302         <description>
10303           Can generate events when a method is compiled or unloaded
10304         </description>
10305       </capabilityfield>
10306       <capabilityfield id="can_generate_monitor_events"
10307                        disp1="can_generate" disp2="_monitor_events"
10308                        >
10309         <description>
10310           Can generate events on monitor activity
10311         </description>
10312       </capabilityfield>
10313       <capabilityfield id="can_generate_vm_object_alloc_events"
10314                        disp1="can_generate" disp2="_vm_object_alloc_events"
10315                        >
10316         <description>
10317           Can generate events on VM allocation of an object
10318         </description>
10319       </capabilityfield>
10320       <capabilityfield id="can_generate_native_method_bind_events"
10321                        disp1="can_generate" disp2="_native_method_bind_events"
10322                        >
10323         <description>
10324           Can generate events when a native method is bound to its
10325           implementation
10326         </description>
10327       </capabilityfield>
10328       <capabilityfield id="can_generate_garbage_collection_events"
10329                        disp1="can_generate" disp2="_garbage_collection_events"
10330                        >
10331         <description>
10332           Can generate events when garbage collection begins or ends
10333         </description>
10334       </capabilityfield>
10335       <capabilityfield id="can_generate_object_free_events"
10336                        disp1="can_generate" disp2="_object_free_events"
10337                        >
10338         <description>
10339           Can generate events when the garbage collector frees an object
10340         </description>
10341       </capabilityfield>
10342       <capabilityfield id="can_force_early_return" since="1.1">
10343         <description>
10344           Can return early from a method, as described in the
10345           <internallink id="ForceEarlyReturn">Force Early Return category</internallink>.
10346         </description>
10347       </capabilityfield>
10348       <capabilityfield id="can_get_owned_monitor_stack_depth_info" since="1.1">
10349         <description>
10350           Can get information about owned monitors with stack depth -
10351           <functionlink id="GetOwnedMonitorStackDepthInfo"></functionlink>
10352         </description>
10353       </capabilityfield>
10354       <capabilityfield id="can_get_constant_pool" since="1.1">
10355         <description>
10356           Can get the constant pool of a class -
10357           <functionlink id="GetConstantPool"></functionlink>
10358         </description>
10359       </capabilityfield>
10360       <capabilityfield id="can_set_native_method_prefix" since="1.1">
10361         <description>
10362           Can set prefix to be applied when native method cannot be resolved -
10363           <functionlink id="SetNativeMethodPrefix"/> and
10364           <functionlink id="SetNativeMethodPrefixes"/>
10365         </description>
10366       </capabilityfield>
10367       <capabilityfield id="can_retransform_classes" since="1.1">
10368         <description>
10369           Can retransform classes with <functionlink id="RetransformClasses"/>.
10370           In addition to the restrictions imposed by the specific
10371           implementation on this capability (see the
10372           <internallink id="capability">Capability</internallink> section),
10373           this capability must be set before the
10374           <eventlink id="ClassFileLoadHook"/> event is enabled for the
10375           first time in this environment.
10376           An environment that possesses this capability at the time that
10377           <code>ClassFileLoadHook</code> is enabled for the first time is
10378           said to be <i>retransformation capable</i>.
10379           An environment that does not possess this capability at the time that
10380           <code>ClassFileLoadHook</code> is enabled for the first time is
10381           said to be <i>retransformation incapable</i>.
10382         </description>
10383       </capabilityfield>
10384       <capabilityfield id="can_retransform_any_class" since="1.1">
10385         <description>
10386           <functionlink id="RetransformClasses"/> can be called on any modifiable class.
10387           See <functionlink id="IsModifiableClass"/>.
10388           (<fieldlink id="can_retransform_classes" struct="jvmtiCapabilities"/>
10389           must also be set)
10390         </description>
10391       </capabilityfield>
10392       <capabilityfield id="can_generate_resource_exhaustion_heap_events" since="1.1">
10393         <description>
10394           Can generate events when the VM is unable to allocate memory from
10395           the <tm>Java</tm> platform heap.
10396           See <eventlink id="ResourceExhausted"/>.
10397         </description>
10398       </capabilityfield>
10399       <capabilityfield id="can_generate_resource_exhaustion_threads_events" since="1.1">
10400         <description>
10401           Can generate events when the VM is unable to create a thread.
10402           See <eventlink id="ResourceExhausted"/>.
10403         </description>
10404       </capabilityfield>
10405       <capabilityfield id="can_generate_early_vmstart" since="9">
10406         <description>
10407           Can generate the <code>VMStart</code> event early.
10408           See <eventlink id="VMStart"/>.
10409         </description>
10410       </capabilityfield>
10411       <capabilityfield id="can_generate_early_class_hook_events" since="9">
10412         <description>
10413           Can generate the <eventlink id="ClassFileLoadHook"/> events
10414           in the primordial phase. If this capability and
10415           <internallink id="jvmtiCapabilities.can_generate_all_class_hook_events">
10416           <code>can_generate_all_class_hook_events</code></internallink>
10417           are enabled then the <eventlink id="ClassFileLoadHook"/> events
10418           can be posted for classes loaded in the primordial phase.
10419           See <eventlink id="ClassFileLoadHook"/>.
10420         </description>
10421       </capabilityfield>
10422       <capabilityfield id="can_generate_sampled_object_alloc_events" since="11">
10423         <description>
10424           Can generate sampled allocation events.
10425           If this capability is enabled then the heap sampling method
10426           <functionlink id="SetHeapSamplingInterval"></functionlink> can be
10427           called and <eventlink id="SampledObjectAlloc"></eventlink> events can be generated.
10428         </description>
10429       </capabilityfield>
10430     </capabilitiestypedef>
10431 
10432     <function id="GetPotentialCapabilities" jkernel="yes" phase="onload" num="140">
10433       <synopsis>Get Potential Capabilities</synopsis>
10434       <description>
10435         Returns via <paramlink id="capabilities_ptr"></paramlink> the <jvmti/>
10436         features that can potentially be possessed by this environment
10437         at this time.
10438         The returned capabilities differ from the complete set of capabilities
10439         implemented by the VM in two cases: another environment possesses
10440         capabilities that can only be possessed by one environment, or the
10441         current <functionlink id="GetPhase">phase</functionlink> is live,
10442         and certain capabilities can only be added during the <code>OnLoad</code> phase.
10443         The <functionlink id="AddCapabilities"></functionlink> function
10444         may be used to set any or all or these capabilities.
10445         Currently possessed capabilities are included.
10446         <p/>
10447         Typically this function is used in the <code>OnLoad</code> function.
10448         Some virtual machines may allow a limited set of capabilities to be
10449         added in the live phase.
10450         In this case, the set of potentially available capabilities
10451         will likely differ from the <code>OnLoad</code> phase set.
10452         <p/>
10453         See the
10454         <internallink id="capabilityExamples">Capability Examples</internallink>.
10455       </description>
10456       <origin>new</origin>
10457       <capabilities>
10458       </capabilities>
10459       <parameters>
10460         <param id="capabilities_ptr">
10461           <outptr><struct>jvmtiCapabilities</struct></outptr>
10462           <description>
10463             On return, points to the <jvmti/> capabilities that may be added.
10464           </description>
10465         </param>
10466       </parameters>
10467       <errors>
10468       </errors>
10469     </function>
10470 
10471     <elide>
10472     <function id="EstimateCostOfCapabilities" phase="onload" num="141">
10473       <synopsis>Estimate Cost Of Capabilities</synopsis>
10474       <description>
10475         <issue>There is strong opposition to this function.  The concern is
10476           that it would be difficult or impossible to provide meaningful
10477           numbers, as the amount of impact is conditional on many factors
10478           that a single number could not represent.  There is doubt that
10479           conditional implementations would be used or are even a good idea.
10480           The thought is that release documentation for the implementation
10481           would be the best means of exposing this information.
10482           Unless new arguments are presented, I intend to remove this
10483           function in the next revision.
10484         </issue>
10485         <p/>
10486         Return via the <paramlink id="time_impact_ptr"></paramlink> and
10487         <paramlink id="space_impact_ptr"></paramlink> an estimate of the impact
10488         of adding the capabilities pointed to by
10489         <paramlink id="capabilities_ptr"></paramlink>.
10490         The returned estimates are in percentage of additional overhead, thus
10491         a time impact of 100 mean the application might run
10492         at half the speed.
10493         The estimates are very rough approximations and are not guaranteed.
10494         Note also, that the estimates are of the impact of having the
10495         capability available--when and if it is used the impact may be
10496         much greater.
10497         Estimates can be for a single capability or for a set of
10498         capabilities.  Note that the costs are not necessarily additive,
10499         adding support for one capability might make another available
10500         for free or conversely having two capabilities at once may
10501         have multiplicative impact.
10502         Estimates are relative to the current set of capabilities -
10503         that is, how much more impact given the currently possessed capabilities.
10504         <p/>
10505         Typically this function is used in the OnLoad function,
10506         some virtual machines may allow a limited set of capabilities to be
10507         added in the live phase.
10508         In this case, the set of potentially available capabilities
10509         will likely differ from the OnLoad phase set.
10510         <p/>
10511         See the
10512         <internallink id="capabilityExamples">Capability Examples</internallink>.
10513       </description>
10514       <origin>new</origin>
10515       <capabilities>
10516       </capabilities>
10517       <parameters>
10518         <param id="capabilities_ptr">
10519           <inptr><struct>jvmtiCapabilities</struct></inptr>
10520           <description>
10521             points to the <jvmti/> capabilities to evaluate.
10522           </description>
10523         </param>
10524         <param id="time_impact_ptr">
10525           <outptr><jint/></outptr>
10526           <description>
10527             On return, points to the estimated percentage increase in
10528             run time if this capability was added.
10529           </description>
10530         </param>
10531         <param id="space_impact_ptr">
10532           <outptr><jint/></outptr>
10533           <description>
10534             On return, points to the estimated percentage increase in
10535             memory space used if this capability was added.
10536           </description>
10537         </param>
10538       </parameters>
10539       <errors>
10540         <error id="JVMTI_ERROR_NOT_AVAILABLE">
10541           The desired capabilities are not even potentially available.
10542         </error>
10543       </errors>
10544     </function>
10545     </elide>
10546 
10547     <function id="AddCapabilities" jkernel="yes" phase="onload" num="142">
10548       <synopsis>Add Capabilities</synopsis>
10549       <description>
10550         Set new capabilities by adding the capabilities
10551         whose values are set to one (<code>1</code>) in
10552         <code>*</code><paramlink id="capabilities_ptr"></paramlink>.
10553         All previous capabilities are retained.
10554         Typically this function is used in the <code>OnLoad</code> function.
10555         Some virtual machines may allow a limited set of capabilities to be
10556         added in the live phase.
10557         <p/>
10558         See the
10559         <internallink id="capabilityExamples">Capability Examples</internallink>.
10560       </description>
10561       <origin>new</origin>
10562       <capabilities>
10563       </capabilities>
10564       <parameters>
10565         <param id="capabilities_ptr">
10566           <inptr><struct>jvmtiCapabilities</struct></inptr>
10567           <description>
10568             Points to the <jvmti/> capabilities to add.
10569           </description>
10570         </param>
10571       </parameters>
10572       <errors>
10573         <error id="JVMTI_ERROR_NOT_AVAILABLE">
10574           The desired capabilities are not even potentially available.
10575         </error>
10576       </errors>
10577     </function>
10578 
10579 
10580     <function id="RelinquishCapabilities" phase="onload" num="143">
10581       <synopsis>Relinquish Capabilities</synopsis>
10582       <description>
10583         Relinquish the capabilities
10584         whose values are set to one (<code>1</code>) in
10585         <code>*</code><paramlink id="capabilities_ptr"></paramlink>.
10586         Some implementations may allow only one environment to have a capability
10587         (see the <internallink id="capability">capability introduction</internallink>).
10588         This function releases capabilities
10589         so that they may be used by other agents.
10590         All other capabilities are retained.
10591         The capability will no longer be present in <functionlink id="GetCapabilities"></functionlink>.
10592         Attempting to relinquish a capability that the agent does not possess is not an error.
10593           <issue>
10594             It is possible for the agent to be actively using capabilities
10595             which are being relinquished.  For example, a thread is currently
10596             suspended and can_suspend is being relinquished or an event is currently
10597             enabled and can_generate_whatever is being relinquished.
10598             There are three possible ways we could spec this:
10599             <ul>
10600               <li>relinquish automatically releases them</li>
10601               <li>relinquish checks and returns some error code if held</li>
10602               <li>it is the agent's responsibility and it is not checked</li>
10603             </ul>
10604             One of these should be chosen.
10605           </issue>
10606       </description>
10607       <origin>new</origin>
10608       <capabilities>
10609       </capabilities>
10610       <parameters>
10611         <param id="capabilities_ptr">
10612           <inptr><struct>jvmtiCapabilities</struct></inptr>
10613           <description>
10614             Points to the <jvmti/> capabilities to relinquish.
10615           </description>
10616         </param>
10617       </parameters>
10618       <errors>
10619       </errors>
10620     </function>
10621 
10622 
10623 
10624     <function id="GetCapabilities" jkernel="yes" phase="any" num="89">
10625       <synopsis>Get Capabilities</synopsis>
10626         <description>
10627           Returns via <paramlink id="capabilities_ptr"></paramlink> the optional <jvmti/>
10628           features which this environment currently possesses.
10629           Each possessed capability is indicated by a one (<code>1</code>) in the
10630           corresponding field of the <internallink id="jvmtiCapabilities">capabilities
10631           structure</internallink>.
10632           An environment does not possess a capability unless it has been successfully added with
10633           <functionlink id="AddCapabilities"/>.
10634           An environment only loses possession of a capability if it has been relinquished with
10635           <functionlink id="RelinquishCapabilities"/>. Thus, this function returns the net result
10636           of the <code>AddCapabilities</code> and <code>RelinquishCapabilities</code> calls which
10637           have been made.
10638           <p/>
10639           See the
10640           <internallink id="capabilityExamples">Capability Examples</internallink>.
10641         </description>
10642       <origin>jvmdiClone</origin>
10643       <capabilities>
10644       </capabilities>
10645       <parameters>
10646         <param id="capabilities_ptr">
10647           <outptr><struct>jvmtiCapabilities</struct></outptr>
10648           <description>
10649             On return, points to the <jvmti/> capabilities.
10650           </description>
10651         </param>
10652       </parameters>
10653       <errors>
10654       </errors>
10655     </function>
10656 
10657   </category>
10658 
10659 
10660   <category id="timers" label="Timers">
10661 
10662       <intro>
10663         These functions provide timing information.
10664         The resolution at which the time is updated is not specified.
10665         They provides nanosecond precision, but not necessarily nanosecond accuracy.
10666         Details about the timers, such as their maximum values, can be accessed with
10667         the timer information functions.
10668       </intro>
10669 
10670       <typedef id="jvmtiTimerInfo" label="Timer Info">
10671         <description>
10672           The information function for each timer returns this data structure.
10673         </description>
10674         <field id="max_value">
10675           <jlong/>
10676             <description>
10677               The maximum value the timer can reach.
10678               After this value is reached the timer wraps back to zero.
10679               This is an unsigned value.  If tested or printed as a jlong (signed value)
10680               it may appear to be a negative number.
10681             </description>
10682         </field>
10683         <field id="may_skip_forward">
10684           <jboolean/>
10685           <description>
10686             If true, the timer can be externally adjusted and as a result skip forward.
10687             If false, the timer value will never increase faster than real time.
10688           </description>
10689         </field>
10690         <field id="may_skip_backward">
10691           <jboolean/>
10692           <description>
10693             If true, the timer can be externally adjusted and as a result skip backward.
10694             If false, the timer value will be monotonically increasing.
10695           </description>
10696         </field>
10697         <field id="kind">
10698           <enum>jvmtiTimerKind</enum>
10699           <description>
10700             The kind of timer.
10701             On a platform that does not distinguish between user and system time, <datalink
10702                  id="JVMTI_TIMER_TOTAL_CPU"><code>JVMTI_TIMER_TOTAL_CPU</code></datalink>
10703             is returned.
10704           </description>
10705         </field>
10706         <field id="reserved1">
10707           <jlong/>
10708             <description>
10709               Reserved for future use.
10710             </description>
10711         </field>
10712         <field id="reserved2">
10713           <jlong/>
10714             <description>
10715               Reserved for future use.
10716             </description>
10717         </field>
10718       </typedef>
10719 
10720       <intro>
10721         Where the timer kind is --
10722 
10723         <constants id="jvmtiTimerKind" label="Timer Kinds" kind="enum">
10724           <constant id="JVMTI_TIMER_USER_CPU" num="30">
10725             CPU time that a thread is in user mode.
10726           </constant>
10727           <constant id="JVMTI_TIMER_TOTAL_CPU" num="31">
10728             CPU time that a thread is in user or system mode.
10729           </constant>
10730           <constant id="JVMTI_TIMER_ELAPSED" num="32">
10731             Elapsed time.
10732           </constant>
10733         </constants>
10734       </intro>
10735 
10736     <function id="GetCurrentThreadCpuTimerInfo" callbacksafe="safe"  impl="innative notrace" phase="start" num="134">
10737       <synopsis>Get Current Thread CPU Timer Information</synopsis>
10738       <description>
10739         Get information about the
10740         <functionlink id="GetCurrentThreadCpuTime"/> timer.
10741         The fields of the <datalink id="jvmtiTimerInfo"/> structure
10742         are filled in with details about the timer.
10743         This information is specific to the platform and the implementation of
10744         <functionlink id="GetCurrentThreadCpuTime"/> and thus
10745         does not vary by thread nor does it vary
10746         during a particular invocation of the VM.
10747         <p/>
10748         Note that the implementations of <functionlink id="GetCurrentThreadCpuTime"/>
10749         and <functionlink id="GetThreadCpuTime"/> may differ, and thus the values
10750         returned by <code>GetCurrentThreadCpuTimerInfo</code>
10751         and <functionlink id="GetThreadCpuTimerInfo"/>
10752         may differ -- see <functionlink id="GetCurrentThreadCpuTime"/> for more information.
10753       </description>
10754       <origin>new</origin>
10755       <capabilities>
10756         <required id="can_get_current_thread_cpu_time">
10757             Can get current thread CPU time.
10758         </required>
10759       </capabilities>
10760       <parameters>
10761         <param id="info_ptr">
10762           <outptr><struct>jvmtiTimerInfo</struct></outptr>
10763           <description>
10764             On return, filled with information describing the time
10765             returned by <functionlink id="GetCurrentThreadCpuTime"/>.
10766           </description>
10767         </param>
10768       </parameters>
10769       <errors>
10770       </errors>
10771     </function>
10772 
10773     <function id="GetCurrentThreadCpuTime" callbacksafe="safe" impl="innative notrace" phase="start" num="135">
10774       <synopsis>Get Current Thread CPU Time</synopsis>
10775       <description>
10776             Return the CPU time utilized by the current thread.
10777             <p/>
10778             Note that the <functionlink id="GetThreadCpuTime"/>
10779             function provides CPU time for any thread, including
10780             the current thread. <code>GetCurrentThreadCpuTime</code>
10781             exists to support platforms which cannot
10782             supply CPU time for threads other than the current
10783             thread or which have more accurate information for
10784             the current thread (see
10785             <functionlink id="GetCurrentThreadCpuTimerInfo"/> vs
10786             <functionlink id="GetThreadCpuTimerInfo"/>).
10787             On many platforms this call will be equivalent to:
10788 <example>
10789   GetThreadCpuTime(env, NULL, nanos_ptr)
10790 </example>
10791       </description>
10792       <origin>new</origin>
10793       <capabilities>
10794         <required id="can_get_current_thread_cpu_time">
10795             Can get current thread CPU time.
10796             <p/>
10797             If this capability is enabled after threads have started,
10798             the implementation may choose any time up
10799             to and including the time that the capability is enabled
10800             as the point where CPU time collection starts.
10801             <p/>
10802             This capability must be potentially available on any
10803             platform where
10804             <internallink id="jvmtiCapabilities.can_get_thread_cpu_time"><code>can_get_thread_cpu_time</code></internallink>
10805             is potentially available.
10806         </required>
10807       </capabilities>
10808       <parameters>
10809         <param id="nanos_ptr">
10810           <outptr><jlong/></outptr>
10811           <description>
10812             On return, points to the CPU time used by this thread
10813             in nanoseconds.
10814             This is an unsigned value.  If tested or printed as a jlong (signed value)
10815             it may appear to be a negative number.
10816           </description>
10817         </param>
10818       </parameters>
10819       <errors>
10820       </errors>
10821     </function>
10822 
10823     <function id="GetThreadCpuTimerInfo" num="136">
10824       <synopsis>Get Thread CPU Timer Information</synopsis>
10825       <description>
10826         Get information about the
10827         <functionlink id="GetThreadCpuTime"/> timer.
10828         The fields of the <datalink id="jvmtiTimerInfo"/> structure
10829         are filled in with details about the timer.
10830         This information is specific to the platform and the implementation of
10831         <functionlink id="GetThreadCpuTime"/> and thus
10832         does not vary by thread nor does it vary
10833         during a particular invocation of the VM.
10834         <p/>
10835         Note that the implementations of <functionlink id="GetCurrentThreadCpuTime"/>
10836         and <functionlink id="GetThreadCpuTime"/> may differ, and thus the values
10837         returned by <functionlink id="GetCurrentThreadCpuTimerInfo"/>
10838         and <code>GetThreadCpuTimerInfo</code>
10839         may differ -- see <functionlink id="GetCurrentThreadCpuTime"/> for more information.
10840       </description>
10841       <origin>new</origin>
10842       <capabilities>
10843         <required id="can_get_thread_cpu_time">
10844             Can get thread CPU time.
10845         </required>
10846       </capabilities>
10847       <parameters>
10848         <param id="info_ptr">
10849           <outptr><struct>jvmtiTimerInfo</struct></outptr>
10850           <description>
10851             On return, filled with information describing the time
10852             returned by <functionlink id="GetThreadCpuTime"/>.
10853           </description>
10854         </param>
10855       </parameters>
10856       <errors>
10857       </errors>
10858     </function>
10859 
10860     <function id="GetThreadCpuTime" num="137">
10861       <synopsis>Get Thread CPU Time</synopsis>
10862       <description>
10863           Return the CPU time utilized by the specified thread.
10864           <p/>
10865           Get information about this timer with
10866           <functionlink id="GetThreadCpuTimerInfo"/>.
10867       </description>
10868       <origin>new</origin>
10869       <capabilities>
10870         <required id="can_get_thread_cpu_time">
10871             Can get thread CPU time.
10872             <p/>
10873             If this capability is enabled after threads have started,
10874             the implementation may choose any time up
10875             to and including the time that the capability is enabled
10876             as the point where CPU time collection starts.
10877         </required>
10878       </capabilities>
10879       <parameters>
10880         <param id="thread">
10881           <jthread null="current"/>
10882             <description>
10883               The thread to query.
10884             </description>
10885         </param>
10886         <param id="nanos_ptr">
10887           <outptr><jlong/></outptr>
10888           <description>
10889             On return, points to the CPU time used by the specified thread
10890             in nanoseconds.
10891             This is an unsigned value.  If tested or printed as a jlong (signed value)
10892             it may appear to be a negative number.
10893           </description>
10894         </param>
10895       </parameters>
10896       <errors>
10897       </errors>
10898     </function>
10899 
10900     <function id="GetTimerInfo" phase="any" callbacksafe="safe" num="138">
10901       <synopsis>Get Timer Information</synopsis>
10902       <description>
10903         Get information about the
10904         <functionlink id="GetTime"/> timer.
10905         The fields of the <datalink id="jvmtiTimerInfo"/> structure
10906         are filled in with details about the timer.
10907         This information will not change during a particular invocation of the VM.
10908       </description>
10909       <origin>new</origin>
10910       <capabilities>
10911       </capabilities>
10912       <parameters>
10913         <param id="info_ptr">
10914           <outptr><struct>jvmtiTimerInfo</struct></outptr>
10915           <description>
10916             On return, filled with information describing the time
10917             returned by <functionlink id="GetTime"/>.
10918           </description>
10919         </param>
10920       </parameters>
10921       <errors>
10922       </errors>
10923     </function>
10924 
10925     <function id="GetTime" phase="any" callbacksafe="safe" num="139">
10926       <synopsis>Get Time</synopsis>
10927       <description>
10928           Return the current value of the system timer, in nanoseconds.
10929           <p/>
10930           The value returned represents nanoseconds since some fixed but
10931           arbitrary time (perhaps in the future, so values may be
10932           negative).  This function provides nanosecond precision, but not
10933           necessarily nanosecond accuracy. No guarantees are made about
10934           how frequently values change.
10935           <p/>
10936           Get information about this timer with
10937           <functionlink id="GetTimerInfo"/>.
10938       </description>
10939       <origin>new</origin>
10940       <capabilities>
10941       </capabilities>
10942       <parameters>
10943         <param id="nanos_ptr">
10944           <outptr><jlong/></outptr>
10945           <description>
10946             On return, points to the time in nanoseconds.
10947             This is an unsigned value.  If tested or printed as a jlong (signed value)
10948             it may appear to be a negative number.
10949           </description>
10950         </param>
10951       </parameters>
10952       <errors>
10953       </errors>
10954     </function>
10955 
10956     <function id="GetAvailableProcessors" phase="any" num="144">
10957       <synopsis>Get Available Processors</synopsis>
10958       <description>
10959           Returns the number of processors available to the Java virtual machine.
10960           <p/>
10961           This value may change during a particular invocation of the virtual machine.
10962           Applications that are sensitive to the number of available processors should
10963           therefore occasionally poll this property.
10964       </description>
10965       <origin>new</origin>
10966       <capabilities>
10967       </capabilities>
10968       <parameters>
10969         <param id="processor_count_ptr">
10970           <outptr><jint/></outptr>
10971           <description>
10972             On return, points to the maximum number of processors available to the
10973             virtual machine; never smaller than one.
10974           </description>
10975         </param>
10976       </parameters>
10977       <errors>
10978       </errors>
10979     </function>
10980 
10981   </category>
10982 
10983 
10984   <category id="classLoaderSearch" label="Class Loader Search">
10985 
10986     <intro>
10987       These functions allow the agent to add to the locations that a class loader searches for a class.
10988       This is useful for installing instrumentation under the correct class loader.
10989     </intro>
10990 
10991     <function id="AddToBootstrapClassLoaderSearch" jkernel="yes" phase="onload" num="149">
10992       <synopsis>Add To Bootstrap Class Loader Search</synopsis>
10993       <description>
10994           This function can be used to cause instrumentation classes to be defined by the
10995           bootstrap class loader. See <vmspec chapter="5.3.1"/>.
10996           After the bootstrap
10997           class loader unsuccessfully searches for a class, the specified platform-dependent
10998           search path <paramlink id="segment"/> will be searched as well. Only one segment may be specified in
10999           the <paramlink id="segment"/>. This function may be called multiple times to add multiple segments,
11000           the segments will be searched in the order that this function was called.
11001           <p/>
11002           In the <code>OnLoad</code> phase the function may be used to specify any platform-dependent
11003           search path segment to be searched after the bootstrap class loader unsuccessfully searches
11004           for a class. The segment is typically a directory or JAR file.
11005           <p/>
11006           In the live phase the <paramlink id="segment"/> may be used to specify any platform-dependent
11007           path to a <externallink id="jar/jar.html">
11008           JAR file</externallink>. The agent should take care that the JAR file does not
11009           contain any classes or resources other than those to be defined by the bootstrap
11010           class loader for the purposes of instrumentation.
11011           <p/>
11012           <vmspec/> specifies that a subsequent attempt to resolve a symbolic
11013           reference that the Java virtual machine has previously unsuccessfully attempted
11014           to resolve always fails with the same error that was thrown as a result of the
11015           initial resolution attempt. Consequently, if the JAR file contains an entry
11016           that corresponds to a class for which the Java virtual machine has
11017           unsuccessfully attempted to resolve a reference, then subsequent attempts to
11018           resolve that reference will fail with the same error as the initial attempt.
11019       </description>
11020       <origin>new</origin>
11021       <capabilities>
11022       </capabilities>
11023       <parameters>
11024         <param id="segment">
11025           <inbuf><char/></inbuf>
11026           <description>
11027             The platform-dependent search path segment, encoded as a
11028             <internallink id="mUTF">modified UTF-8</internallink> string.
11029           </description>
11030         </param>
11031       </parameters>
11032       <errors>
11033         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
11034           <paramlink id="segment"/> is an invalid path. In the live phase, anything other than an
11035            existing JAR file is an invalid path.
11036         </error>
11037       </errors>
11038     </function>
11039 
11040     <function id="AddToSystemClassLoaderSearch" jkernel="yes" phase="onload" num="151" since="1.1">
11041       <synopsis>Add To System Class Loader Search</synopsis>
11042       <description>
11043           This function can be used to cause instrumentation classes to be
11044           defined by the system class loader. See <vmspec chapter="5.3.2"/>.
11045           After the class loader unsuccessfully searches for a class, the specified platform-dependent search
11046           path <paramlink id="segment"/> will be searched as well. Only one segment may be specified in the
11047           <paramlink id="segment"/>. This function may be called multiple times to add multiple segments, the
11048           segments will be searched in the order that this function was called.
11049           <p/>
11050           In the <code>OnLoad</code> phase the function may be used to specify any platform-dependent
11051           search path segment to be searched after the system class loader unsuccessfully searches
11052           for a class. The segment is typically a directory or JAR file.
11053           <p/>
11054           In the live phase the <paramlink id="segment"/> is a platform-dependent path to a
11055           <externallink id="jar/jar.html">JAR file</externallink> to be
11056           searched after the system class loader unsuccessfully searches for a class. The agent should
11057           take care that the JAR file does not contain any classes or resources other than those to be
11058           defined by the system class loader for the purposes of instrumentation.
11059           <p/>
11060           In the live phase the system class loader supports adding a JAR file to be searched if
11061           the system class loader implements a method name <code>appendToClassPathForInstrumentation</code>
11062           which takes a single parameter of type <code>java.lang.String</code>. The method is not required
11063           to have <code>public</code> access.
11064           <p/>
11065           <vmspec/> specifies that a subsequent attempt to resolve a symbolic
11066           reference that the Java virtual machine has previously unsuccessfully attempted
11067           to resolve always fails with the same error that was thrown as a result of the
11068           initial resolution attempt. Consequently, if the JAR file contains an entry
11069           that corresponds to a class for which the Java virtual machine has
11070           unsuccessfully attempted to resolve a reference, then subsequent attempts to
11071           resolve that reference will fail with the same error as the initial attempt.
11072       </description>
11073       <origin>new</origin>
11074       <capabilities>
11075       </capabilities>
11076       <parameters>
11077         <param id="segment">
11078           <inbuf><char/></inbuf>
11079           <description>
11080             The platform-dependent search path segment, encoded as a
11081             <internallink id="mUTF">modified UTF-8</internallink> string.
11082           </description>
11083         </param>
11084       </parameters>
11085       <errors>
11086         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
11087           <paramlink id="segment"/> is an invalid path. In the live phase, anything other than an
11088            existing JAR file is an invalid path.
11089         </error>
11090         <error id="JVMTI_ERROR_CLASS_LOADER_UNSUPPORTED">
11091           Operation not supported by the system class loader.
11092         </error>
11093       </errors>
11094     </function>
11095 
11096   </category>
11097 
11098 
11099   <category id="props" label="System Properties">
11100 
11101     <intro>
11102       These functions get and set system properties.
11103     </intro>
11104 
11105     <function id="GetSystemProperties" phase="onload" num="130">
11106       <synopsis>Get System Properties</synopsis>
11107       <description>
11108         The list of VM system property keys which may be used with
11109         <functionlink id="GetSystemProperty"/> is returned.
11110         It is strongly recommended that virtual machines provide the
11111         following property keys:
11112         <ul>
11113           <li><code>java.vm.vendor</code></li>
11114           <li><code>java.vm.version</code></li>
11115           <li><code>java.vm.name</code></li>
11116           <li><code>java.vm.info</code></li>
11117           <li><code>java.library.path</code></li>
11118           <li><code>java.class.path</code></li>
11119         </ul>
11120         Provides access to system properties defined by and used
11121         by the VM.
11122         Properties set on the command-line are included.
11123         This allows getting and setting of these properties
11124         before the VM even begins executing bytecodes.
11125         Since this is a VM view of system properties, the set of available
11126         properties will usually be different than that
11127         in <code>java.lang.System.getProperties</code>.
11128         JNI method invocation may be used to access
11129         <code>java.lang.System.getProperties</code>.
11130         <p/>
11131         The set of properties may grow during execution.
11132       </description>
11133       <origin>new</origin>
11134       <capabilities>
11135       </capabilities>
11136       <parameters>
11137         <param id="count_ptr">
11138           <outptr><jint/></outptr>
11139           <description>
11140             On return, points to the number of property keys returned.
11141           </description>
11142         </param>
11143         <param id="property_ptr">
11144           <allocallocbuf outcount="count_ptr"><char/></allocallocbuf>
11145           <description>
11146             On return, points to an array of property keys, encoded as
11147             <internallink id="mUTF">modified UTF-8</internallink> strings.
11148           </description>
11149         </param>
11150       </parameters>
11151       <errors>
11152       </errors>
11153     </function>
11154 
11155     <function id="GetSystemProperty" phase="onload" num="131">
11156       <synopsis>Get System Property</synopsis>
11157       <description>
11158         Return a VM system property value given the property key.
11159         <p/>
11160         The function <functionlink id="GetSystemProperties"/>
11161         returns the set of property keys which may be used.
11162         The properties which can be retrieved may grow during
11163         execution.
11164         <p/>
11165         Since this is a VM view of system properties, the values
11166         of properties may differ from that returned by
11167         <code>java.lang.System.getProperty(String)</code>.
11168         A typical VM might copy the values of the VM system
11169         properties into the <code>Properties</code> held by
11170         <code>java.lang.System</code> during the initialization
11171         of that class. Thereafter any changes to the VM system
11172         properties (with <functionlink id="SetSystemProperty"/>)
11173         or the <code>java.lang.System</code> system properties
11174         (with <code>java.lang.System.setProperty(String,String)</code>)
11175         would cause the values to diverge.
11176         JNI method invocation may be used to access
11177         <code>java.lang.System.getProperty(String)</code>.
11178       </description>
11179       <origin>new</origin>
11180       <capabilities>
11181       </capabilities>
11182       <parameters>
11183         <param id="property">
11184           <inbuf><char/></inbuf>
11185           <description>
11186             The key of the property to retrieve, encoded as a
11187             <internallink id="mUTF">modified UTF-8</internallink> string.
11188           </description>
11189         </param>
11190         <param id="value_ptr">
11191           <allocbuf><char/></allocbuf>
11192           <description>
11193             On return, points to the property value, encoded as a
11194             <internallink id="mUTF">modified UTF-8</internallink> string.
11195           </description>
11196         </param>
11197       </parameters>
11198       <errors>
11199         <error id="JVMTI_ERROR_NOT_AVAILABLE">
11200           This property is not available.
11201           Use <functionlink id="GetSystemProperties"/> to find available properties.
11202         </error>
11203       </errors>
11204     </function>
11205 
11206     <function id="SetSystemProperty" phase="onloadOnly" num="132">
11207       <synopsis>Set System Property</synopsis>
11208       <description>
11209         Set a VM system property value.
11210         <p/>
11211         The function <functionlink id="GetSystemProperties"/>
11212         returns the set of property keys, some of these may be settable.
11213         See <functionlink id="GetSystemProperty"/>.
11214       </description>
11215       <origin>new</origin>
11216       <capabilities>
11217       </capabilities>
11218       <parameters>
11219         <param id="property">
11220           <inbuf><char/></inbuf>
11221           <description>
11222             The key of the property, encoded as a
11223             <internallink id="mUTF">modified UTF-8</internallink> string.
11224           </description>
11225         </param>
11226         <param id="value_ptr">
11227           <inbuf>
11228             <char/>
11229             <nullok>
11230               do not set the value, but return <errorlink id="JVMTI_ERROR_NOT_AVAILABLE"/>
11231               if the property is not writeable
11232             </nullok>
11233           </inbuf>
11234           <description>
11235             The property value to set, encoded as a
11236             <internallink id="mUTF">modified UTF-8</internallink> string.
11237           </description>
11238         </param>
11239       </parameters>
11240       <errors>
11241         <error id="JVMTI_ERROR_NOT_AVAILABLE">
11242           This property is not available or is not writeable.
11243         </error>
11244       </errors>
11245     </function>
11246 
11247   </category>
11248 
11249   <category id="general" label="General">
11250 
11251     <intro>
11252     </intro>
11253 
11254     <function id="GetPhase" jkernel="yes" phase="any" num="133">
11255       <synopsis>Get Phase</synopsis>
11256       <description>
11257           Return the current phase of VM execution.
11258           The phases proceed in sequence:
11259           <constants id="jvmtiPhase" label="Phases of execution" kind="enum">
11260             <constant id="JVMTI_PHASE_ONLOAD" num="1">
11261               <code>OnLoad</code> phase: while in the
11262               <internallink id="onload"><code>Agent_OnLoad</code></internallink>
11263               or, for statically linked agents, the <internallink id="onload">
11264               <code>Agent_OnLoad_&lt;agent-lib-name&gt;
11265               </code></internallink> function.
11266             </constant>
11267             <constant id="JVMTI_PHASE_PRIMORDIAL" num="2">
11268               Primordial phase: between return from <code>Agent_OnLoad</code>
11269               or <code>Agent_OnLoad_&lt;agent-lib-name&gt;</code> and the
11270               <code>VMStart</code> event.
11271             </constant>
11272             <constant id="JVMTI_PHASE_START" num="6">
11273               Start phase: when the <eventlink id="VMStart"><code>VMStart</code></eventlink> event
11274               is sent and until the <code>VMInit</code> event is sent.
11275             </constant>
11276             <constant id="JVMTI_PHASE_LIVE" num="4">
11277               Live phase: when the <eventlink id="VMInit"><code>VMInit</code></eventlink> event is sent
11278               and until the <eventlink id="VMDeath"></eventlink> event returns.
11279             </constant>
11280             <constant id="JVMTI_PHASE_DEAD" num="8">
11281               Dead phase: after the <eventlink id="VMDeath"></eventlink> event returns or after
11282               start-up failure.
11283             </constant>
11284           </constants>
11285           In the case of start-up failure the VM will proceed directly to the dead
11286           phase skipping intermediate phases and neither a <code>VMInit</code> nor
11287           <code>VMDeath</code> event will be sent.
11288           <p/>
11289           Most <jvmti/> functions operate only in the live phase.
11290           The following functions operate in either the <code>OnLoad</code> or live phases:
11291           <functionphaselist phase="onload"/>
11292           The following functions operate in only the <code>OnLoad</code> phase:
11293           <functionphaselist phase="onloadOnly"/>
11294           The following functions operate in the start or live phases:
11295           <functionphaselist phase="start"/>
11296           The following functions operate in any phase:
11297           <functionphaselist phase="any"/>
11298           JNI functions (except the Invocation API) must only be used in the start or live phases.
11299           <p/>
11300           Most <jvmti/> events are sent only in the live phase.
11301           The following events operate in others phases:
11302           <eventphaselist phase="start"/>
11303           <eventphaselist phase="any"/>
11304       </description>
11305       <origin>new</origin>
11306       <capabilities>
11307       </capabilities>
11308       <parameters>
11309         <param id="phase_ptr">
11310           <outptr><enum>jvmtiPhase</enum></outptr>
11311           <description>
11312             On return, points to the phase.
11313           </description>
11314         </param>
11315       </parameters>
11316       <errors>
11317       </errors>
11318     </function>
11319 
11320     <function id="DisposeEnvironment" jkernel="yes" phase="any" num="127">
11321       <synopsis>Dispose Environment</synopsis>
11322       <description>
11323         Shutdown a <jvmti/> connection created with JNI <code>GetEnv</code>
11324         (see <internallink id="environments"><jvmti/> Environments</internallink>).
11325         Dispose of any resources held by the environment.
11326         <issue>
11327             What resources are reclaimed? What is undone?
11328             Breakpoints,watchpoints removed?
11329         </issue>
11330         Threads suspended by this environment are not resumed by this call,
11331         this must be done explicitly by the agent.
11332         Memory allocated by this environment via calls to <jvmti/> functions
11333         is not released, this can be done explicitly by the agent
11334         by calling <functionlink id="Deallocate"/>.
11335         Raw monitors created by this environment are not destroyed,
11336         this can be done explicitly by the agent
11337         by calling <functionlink id="DestroyRawMonitor"/>.
11338         The state of threads waiting on raw monitors created by this environment
11339         are not affected.
11340         <p/>
11341         Any <functionlink id="SetNativeMethodPrefix">native method
11342         prefixes</functionlink> for this environment will be unset;
11343         the agent must remove any prefixed native methods before
11344         dispose is called.
11345         <p/>
11346         Any <internallink id="capability">capabilities</internallink>
11347         held by this environment are relinquished.
11348         <p/>
11349         Events enabled by this environment will no longer be sent, however
11350         event handlers currently running will continue to run.  Caution must
11351         be exercised in the design of event handlers whose environment may
11352         be disposed and thus become invalid during their execution.
11353         <p/>
11354         This environment may not be used after this call.
11355         This call returns to the caller.
11356       </description>
11357       <origin>new</origin>
11358       <capabilities>
11359       </capabilities>
11360       <parameters>
11361       </parameters>
11362       <errors>
11363       </errors>
11364     </function>
11365 
11366     <function id="SetEnvironmentLocalStorage" jkernel="yes" phase="any" callbacksafe="safe" impl="innative notrace" num="148">
11367       <synopsis>Set Environment Local Storage</synopsis>
11368       <description>
11369         The VM stores a pointer value associated with each environment.
11370         This pointer value is called <i>environment-local storage</i>.
11371         This value is <code>NULL</code> unless set with this function.
11372         Agents can allocate memory in which they store environment specific
11373         information. By setting environment-local storage it can then be
11374         accessed with
11375         <functionlink id="GetEnvironmentLocalStorage"></functionlink>.
11376         <p/>
11377         Called by the agent to set the value of the <jvmti/>
11378         environment-local storage. <jvmti/> supplies to the agent a pointer-size
11379         environment-local storage that can be used to record per-environment
11380         information.
11381       </description>
11382       <origin>new</origin>
11383       <capabilities>
11384       </capabilities>
11385       <parameters>
11386         <param id="data">
11387           <inbuf>
11388             <void/>
11389             <nullok>value is set to <code>NULL</code></nullok>
11390           </inbuf>
11391           <description>
11392             The value to be entered into the environment-local storage.
11393           </description>
11394         </param>
11395       </parameters>
11396       <errors>
11397       </errors>
11398     </function>
11399 
11400     <function id="GetEnvironmentLocalStorage" jkernel="yes" phase="any" callbacksafe="safe" impl="innative notrace" num="147">
11401       <synopsis>Get Environment Local Storage</synopsis>
11402       <description>
11403         Called by the agent to get the value of the <jvmti/> environment-local
11404         storage.
11405       </description>
11406       <origin>new</origin>
11407       <capabilities>
11408       </capabilities>
11409       <parameters>
11410         <param id="data_ptr">
11411           <agentbuf><void/></agentbuf>
11412           <description>
11413             Pointer through which the value of the environment local
11414             storage is returned.
11415             If environment-local storage has not been set with
11416             <functionlink id="SetEnvironmentLocalStorage"></functionlink> returned
11417             pointer is <code>NULL</code>.
11418           </description>
11419         </param>
11420       </parameters>
11421       <errors>
11422       </errors>
11423     </function>
11424 
11425     <function id="GetVersionNumber" jkernel="yes" phase="any" num="88">
11426       <synopsis>Get Version Number</synopsis>
11427       <description>
11428         Return the <jvmti/> version via <code>version_ptr</code>.
11429         The return value is the version identifier.
11430         The version identifier includes major, minor and micro
11431         version as well as the interface type.
11432         <constants id="jvmtiVersionInterfaceTypes" label="Version Interface Types" kind="bits">
11433           <constant id="JVMTI_VERSION_INTERFACE_JNI" num="0x00000000">
11434             Value of <code>JVMTI_VERSION_MASK_INTERFACE_TYPE</code> for JNI.
11435           </constant>
11436           <constant id="JVMTI_VERSION_INTERFACE_JVMTI" num="0x30000000">
11437             Value of <code>JVMTI_VERSION_MASK_INTERFACE_TYPE</code> for <jvmti/>.
11438           </constant>
11439         </constants>
11440         <constants id="jvmtiVersionMasks" label="Version Masks" kind="bits">
11441           <constant id="JVMTI_VERSION_MASK_INTERFACE_TYPE" num="0x70000000">
11442             Mask to extract interface type.
11443             The value of the version returned by this function masked with
11444             <code>JVMTI_VERSION_MASK_INTERFACE_TYPE</code> is always
11445             <code>JVMTI_VERSION_INTERFACE_JVMTI</code>
11446             since this is a <jvmti/> function.
11447           </constant>
11448           <constant id="JVMTI_VERSION_MASK_MAJOR" num="0x0FFF0000">
11449             Mask to extract major version number.
11450           </constant>
11451           <constant id="JVMTI_VERSION_MASK_MINOR" num="0x0000FF00">
11452             Mask to extract minor version number.
11453           </constant>
11454           <constant id="JVMTI_VERSION_MASK_MICRO" num="0x000000FF">
11455             Mask to extract micro version number.
11456           </constant>
11457         </constants>
11458         <constants id="jvmtiVersionShifts" label="Version Shifts" kind="bits">
11459           <constant id="JVMTI_VERSION_SHIFT_MAJOR" num="16">
11460             Shift to extract major version number.
11461           </constant>
11462           <constant id="JVMTI_VERSION_SHIFT_MINOR" num="8">
11463             Shift to extract minor version number.
11464           </constant>
11465           <constant id="JVMTI_VERSION_SHIFT_MICRO" num="0">
11466             Shift to extract micro version number.
11467           </constant>
11468         </constants>
11469       </description>
11470       <origin>jvmdi</origin>
11471       <capabilities>
11472       </capabilities>
11473       <parameters>
11474         <param id="version_ptr">
11475           <outptr><jint/></outptr>
11476           <description>
11477             On return, points to the <jvmti/> version.
11478           </description>
11479         </param>
11480       </parameters>
11481       <errors>
11482       </errors>
11483     </function>
11484 
11485 
11486     <function id="GetErrorName" phase="any" num="128">
11487       <synopsis>Get Error Name</synopsis>
11488       <description>
11489         Return the symbolic name for an
11490           <internallink id="ErrorSection">error code</internallink>.
11491         <p/>
11492         For example
11493         <code>GetErrorName(env, JVMTI_ERROR_NONE, &amp;err_name)</code>
11494         would return in <code>err_name</code> the string
11495         <code>"JVMTI_ERROR_NONE"</code>.
11496       </description>
11497       <origin>new</origin>
11498       <capabilities>
11499       </capabilities>
11500       <parameters>
11501         <param id="error">
11502           <enum>jvmtiError</enum>
11503           <description>
11504             The error code.
11505           </description>
11506         </param>
11507         <param id="name_ptr">
11508           <allocbuf><char/></allocbuf>
11509           <description>
11510             On return, points to the error name.
11511             The name is encoded as a
11512             <internallink id="mUTF">modified UTF-8</internallink> string,
11513             but is restricted to the ASCII subset.
11514           </description>
11515         </param>
11516       </parameters>
11517       <errors>
11518       </errors>
11519     </function>
11520 
11521     <function id="SetVerboseFlag" phase="any" num="150">
11522       <synopsis>Set Verbose Flag</synopsis>
11523       <description>
11524         <constants id="jvmtiVerboseFlag" label="Verbose Flag Enumeration" kind="enum">
11525           <constant id="JVMTI_VERBOSE_OTHER" num="0">
11526             Verbose output other than the below.
11527           </constant>
11528           <constant id="JVMTI_VERBOSE_GC" num="1">
11529             Verbose garbage collector output, like that specified with <code>-verbose:gc</code>.
11530           </constant>
11531           <constant id="JVMTI_VERBOSE_CLASS" num="2">
11532             Verbose class loading output, like that specified with <code>-verbose:class</code>.
11533           </constant>
11534           <constant id="JVMTI_VERBOSE_JNI" num="4">
11535             Verbose JNI output, like that specified with <code>-verbose:jni</code>.
11536           </constant>
11537         </constants>
11538         Control verbose output.
11539         This is the output which typically is sent to <code>stderr</code>.
11540       </description>
11541       <origin>new</origin>
11542       <capabilities>
11543       </capabilities>
11544       <parameters>
11545         <param id="flag">
11546           <enum>jvmtiVerboseFlag</enum>
11547           <description>
11548             Which verbose flag to set.
11549           </description>
11550         </param>
11551         <param id="value">
11552           <jboolean/>
11553           <description>
11554             New value of the flag.
11555           </description>
11556         </param>
11557       </parameters>
11558       <errors>
11559       </errors>
11560     </function>
11561 
11562 
11563     <function id="GetJLocationFormat" phase="any" num="129">
11564       <synopsis>Get JLocation Format</synopsis>
11565       <description>
11566         Although the greatest functionality is achieved with location information
11567         referencing the virtual machine bytecode index, the definition of
11568         <code>jlocation</code> has intentionally been left unconstrained to allow VM
11569         implementations that do not have this information.
11570         <p/>
11571         This function describes the representation of <code>jlocation</code> used in this VM.
11572         If the returned format is <datalink id="JVMTI_JLOCATION_JVMBCI"></datalink>,
11573         <code>jlocation</code>s can
11574         be used as in indices into the array returned by
11575         <functionlink id="GetBytecodes"></functionlink>.
11576         <constants id="jvmtiJlocationFormat" label="JLocation Format Enumeration" kind="enum">
11577           <constant id="JVMTI_JLOCATION_JVMBCI" num="1">
11578             <code>jlocation</code> values represent virtual machine
11579             bytecode indices--that is, offsets into the
11580             virtual machine code for a method.
11581           </constant>
11582           <constant id="JVMTI_JLOCATION_MACHINEPC" num="2">
11583             <code>jlocation</code> values represent native machine
11584             program counter values.
11585           </constant>
11586           <constant id="JVMTI_JLOCATION_OTHER" num="0">
11587             <code>jlocation</code> values have some other representation.
11588           </constant>
11589         </constants>
11590       </description>
11591       <origin>new</origin>
11592       <capabilities>
11593       </capabilities>
11594       <parameters>
11595         <param id="format_ptr">
11596           <outptr><enum>jvmtiJlocationFormat</enum></outptr>
11597           <description>
11598             On return, points to the format identifier for <code>jlocation</code> values.
11599           </description>
11600         </param>
11601       </parameters>
11602       <errors>
11603       </errors>
11604     </function>
11605 
11606   </category>
11607 
11608   <category id="heap_monitoring" label="Heap Monitoring">
11609     <function id="SetHeapSamplingInterval" phase="onload" num="156" since="11">
11610       <synopsis>Set Heap Sampling Interval</synopsis>
11611       <description>
11612         Generate a <eventlink id="SampledObjectAlloc"/> event when objects are allocated.
11613         Each thread keeps a counter of bytes allocated. The event will only be generated
11614         when that counter exceeds an average of <paramlink id="sampling_interval"></paramlink>
11615         since the last sample.
11616         <p/>
11617         Setting <paramlink id="sampling_interval"></paramlink> to 0 will cause an event to be
11618         generated by each allocation supported by the system once the new interval is taken into account.
11619         <p/>
11620         Note that updating the new sampling interval might take various number of allocations
11621         to provoke internal data structure updates.  Therefore it is important to
11622         consider the sampling interval as an average. This includes the interval 0, where events
11623         might not be generated straight away for each allocation.
11624       </description>
11625       <origin>new</origin>
11626       <capabilities>
11627         <required id="can_generate_sampled_object_alloc_events"></required>
11628       </capabilities>
11629       <parameters>
11630         <param id="sampling_interval">
11631           <jint/>
11632           <description>
11633             The sampling interval in bytes. The sampler uses a statistical approach to
11634             generate an event, on average, once for every <paramlink id="sampling_interval"/> bytes of
11635             memory allocated by a given thread.
11636             <p/>
11637             Once the new sampling interval is taken into account, 0 as a sampling interval will generate
11638             a sample for every allocation.
11639             <p/>
11640             Note: The overhead of this feature is directly correlated with the sampling interval.
11641             A high sampling interval, such as 1024 bytes, will incur a high overhead.
11642             A lower interval, such as 1024KB, will have a much lower overhead.  Sampling should only
11643             be used with an understanding that it may impact performance.
11644           </description>
11645         </param>
11646       </parameters>
11647       <errors>
11648         <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
11649           <paramlink id="sampling_interval"></paramlink> is less than zero.
11650         </error>
11651       </errors>
11652     </function>
11653   </category>
11654 
11655 </functionsection>
11656 
11657 <errorsection label="Error Reference">
11658   <intro>
11659     Every <jvmti/> function returns a <b><code>jvmtiError</code></b> error code.
11660     <p/>
11661     It is the responsibility of the agent to call <jvmti/> functions with
11662     valid parameters and in the proper context (calling thread is attached,
11663     phase is correct, etc.).
11664     Detecting some error conditions may be difficult, inefficient, or
11665     impossible for an implementation.
11666     The errors listed in
11667     <internallink id="reqerrors">Function Specific Required Errors</internallink>
11668     must be detected by the implementation.
11669     All other errors represent the recommended response to the error
11670     condition.
11671   </intro>
11672 
11673   <errorcategory id="universal-error" label="Universal Errors">
11674     <intro>
11675       The following errors may be returned by any function
11676     </intro>
11677 
11678     <errorid id="JVMTI_ERROR_NONE" num="0">
11679       No error has occurred.  This is the error code that is returned
11680       on successful completion of the function.
11681     </errorid>
11682     <errorid id="JVMTI_ERROR_NULL_POINTER" num="100">
11683       Pointer is unexpectedly <code>NULL</code>.
11684     </errorid>
11685     <errorid id="JVMTI_ERROR_OUT_OF_MEMORY" num="110">
11686       The function attempted to allocate memory and no more memory was
11687       available for allocation.
11688     </errorid>
11689     <errorid id="JVMTI_ERROR_ACCESS_DENIED" num="111">
11690       The desired functionality has not been enabled in this virtual machine.
11691     </errorid>
11692     <errorid id="JVMTI_ERROR_UNATTACHED_THREAD" num="115">
11693       The thread being used to call this function is not attached
11694       to the virtual machine.  Calls must be made from attached threads.
11695       See <code>AttachCurrentThread</code> in the JNI invocation API.
11696     </errorid>
11697     <errorid id="JVMTI_ERROR_INVALID_ENVIRONMENT" num="116">
11698       The <jvmti/> environment provided is no longer connected or is
11699       not an environment.
11700     </errorid>
11701     <errorid id="JVMTI_ERROR_WRONG_PHASE" num="112">
11702       The desired functionality is not available in the current
11703         <functionlink id="GetPhase">phase</functionlink>.
11704       Always returned if the virtual machine has completed running.
11705     </errorid>
11706     <errorid id="JVMTI_ERROR_INTERNAL" num="113">
11707       An unexpected internal error has occurred.
11708     </errorid>
11709   </errorcategory>
11710 
11711   <errorcategory id="reqerrors" label="Function Specific Required Errors">
11712     <intro>
11713       The following errors are returned by some <jvmti/> functions and must
11714       be returned by the implementation when the condition occurs.
11715     </intro>
11716 
11717     <errorid id="JVMTI_ERROR_INVALID_PRIORITY" num="12">
11718       Invalid priority.
11719     </errorid>
11720     <errorid id="JVMTI_ERROR_THREAD_NOT_SUSPENDED" num="13">
11721       Thread was not suspended.
11722     </errorid>
11723     <errorid id="JVMTI_ERROR_THREAD_SUSPENDED" num="14">
11724       Thread already suspended.
11725     </errorid>
11726     <errorid id="JVMTI_ERROR_THREAD_NOT_ALIVE" num="15">
11727       This operation requires the thread to be alive--that is,
11728       it must be started and not yet have died.
11729     </errorid>
11730     <errorid id="JVMTI_ERROR_CLASS_NOT_PREPARED" num="22">
11731       The class has been loaded but not yet prepared.
11732     </errorid>
11733     <errorid id="JVMTI_ERROR_NO_MORE_FRAMES" num="31">
11734       There are no Java programming language or JNI stack frames at the specified depth.
11735     </errorid>
11736     <errorid id="JVMTI_ERROR_OPAQUE_FRAME" num="32">
11737       Information about the frame is not available (e.g. for native frames).
11738     </errorid>
11739     <errorid id="JVMTI_ERROR_DUPLICATE" num="40">
11740       Item already set.
11741     </errorid>
11742     <errorid id="JVMTI_ERROR_NOT_FOUND" num="41">
11743       Desired element (e.g. field or breakpoint) not found
11744     </errorid>
11745     <errorid id="JVMTI_ERROR_NOT_MONITOR_OWNER" num="51">
11746       This thread doesn't own the raw monitor.
11747     </errorid>
11748     <errorid id="JVMTI_ERROR_INTERRUPT" num="52">
11749       The call has been interrupted before completion.
11750     </errorid>
11751     <errorid id="JVMTI_ERROR_UNMODIFIABLE_CLASS" num="79">
11752       The class cannot be modified.
11753     </errorid>
11754     <errorid id="JVMTI_ERROR_UNMODIFIABLE_MODULE" num="80">
11755       The module cannot be modified.
11756     </errorid>
11757     <errorid id="JVMTI_ERROR_NOT_AVAILABLE" num="98">
11758       The functionality is not available in this virtual machine.
11759     </errorid>
11760     <errorid id="JVMTI_ERROR_ABSENT_INFORMATION" num="101">
11761       The requested information is not available.
11762     </errorid>
11763     <errorid id="JVMTI_ERROR_INVALID_EVENT_TYPE" num="102">
11764       The specified event type ID is not recognized.
11765     </errorid>
11766     <errorid id="JVMTI_ERROR_NATIVE_METHOD" num="104">
11767       The requested information is not available for native method.
11768     </errorid>
11769     <errorid id="JVMTI_ERROR_CLASS_LOADER_UNSUPPORTED" num="106">
11770       The class loader does not support this operation.
11771     </errorid>
11772   </errorcategory>
11773 
11774   <errorcategory id="function-specific-errors" label="Function Specific Agent Errors">
11775     <intro>
11776       The following errors are returned by some <jvmti/> functions.
11777       They are returned in the event of invalid parameters passed by the
11778       agent or usage in an invalid context.
11779       An implementation is not required to detect these errors.
11780     </intro>
11781 
11782     <errorid id="JVMTI_ERROR_INVALID_THREAD" num="10">
11783       The passed thread is not a valid thread.
11784     </errorid>
11785     <errorid id="JVMTI_ERROR_INVALID_FIELDID" num="25">
11786       Invalid field.
11787     </errorid>
11788     <errorid id="JVMTI_ERROR_INVALID_MODULE" num="26">
11789       Invalid module.
11790     </errorid>
11791     <errorid id="JVMTI_ERROR_INVALID_METHODID" num="23">
11792       Invalid method.
11793     </errorid>
11794     <errorid id="JVMTI_ERROR_INVALID_LOCATION" num="24">
11795       Invalid location.
11796     </errorid>
11797     <errorid id="JVMTI_ERROR_INVALID_OBJECT" num="20">
11798       Invalid object.
11799     </errorid>
11800     <errorid id="JVMTI_ERROR_INVALID_CLASS" num="21">
11801       Invalid class.
11802     </errorid>
11803     <errorid id="JVMTI_ERROR_TYPE_MISMATCH" num="34">
11804       The variable is not an appropriate type for the function used.
11805     </errorid>
11806     <errorid id="JVMTI_ERROR_INVALID_SLOT" num="35">
11807       Invalid slot.
11808     </errorid>
11809     <errorid id="JVMTI_ERROR_MUST_POSSESS_CAPABILITY" num="99">
11810       The capability being used is false in this environment.
11811     </errorid>
11812     <errorid id="JVMTI_ERROR_INVALID_THREAD_GROUP" num="11">
11813       Thread group invalid.
11814     </errorid>
11815     <errorid id="JVMTI_ERROR_INVALID_MONITOR" num="50">
11816       Invalid raw monitor.
11817     </errorid>
11818     <errorid id="JVMTI_ERROR_ILLEGAL_ARGUMENT" num="103">
11819       Illegal argument.
11820     </errorid>
11821     <errorid id="JVMTI_ERROR_INVALID_TYPESTATE" num="65">
11822       The state of the thread has been modified, and is now inconsistent.
11823     </errorid>
11824     <errorid id="JVMTI_ERROR_UNSUPPORTED_VERSION" num="68">
11825       A new class file has a version number not supported by this VM.
11826     </errorid>
11827     <errorid id="JVMTI_ERROR_INVALID_CLASS_FORMAT" num="60">
11828       A new class file is malformed (the VM would return a <code>ClassFormatError</code>).
11829     </errorid>
11830     <errorid id="JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION" num="61">
11831       The new class file definitions would lead to a circular
11832       definition (the VM would return a <code>ClassCircularityError</code>).
11833     </errorid>
11834     <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED" num="63">
11835       A new class file would require adding a method.
11836     </errorid>
11837     <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED" num="64">
11838       A new class version changes a field.
11839     </errorid>
11840     <errorid id="JVMTI_ERROR_FAILS_VERIFICATION" num="62">
11841       The class bytes fail verification.
11842     </errorid>
11843     <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED" num="66">
11844       A direct superclass is different for the new class
11845       version, or the set of directly implemented
11846       interfaces is different.
11847     </errorid>
11848     <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED" num="67">
11849       A new class version does not declare a method
11850       declared in the old class version.
11851     </errorid>
11852     <errorid id="JVMTI_ERROR_NAMES_DONT_MATCH" num="69">
11853       The class name defined in the new class file is
11854       different from the name in the old class object.
11855     </errorid>
11856     <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED" num="70">
11857       A new class version has different modifiers.
11858     </errorid>
11859     <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED" num="71">
11860       A method in the new class version has different modifiers
11861       than its counterpart in the old class version.
11862     </errorid>
11863     <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED" num="72">
11864       A new class version has unsupported differences in class attributes.
11865     </errorid>
11866   </errorcategory>
11867 </errorsection>
11868 
11869 <eventsection label="Events">
11870   <intro label="Handling Events" id="eventIntro">
11871     Agents can be informed of many events that occur in application
11872     programs.
11873     <p/>
11874     To handle events, designate a set of callback functions with
11875     <functionlink id="SetEventCallbacks"></functionlink>.
11876     For each event the corresponding callback function will be
11877     called.
11878     Arguments to the callback function provide additional
11879     information about the event.
11880     <p/>
11881     The callback function is usually called from within an application
11882     thread. The <jvmti/> implementation does not
11883     queue events in any way. This means
11884     that event callback functions must be written
11885     carefully. Here are some general guidelines. See
11886     the individual event descriptions for further
11887     suggestions.
11888     <p/>
11889     <ul>
11890       <li>Any exception thrown during the execution of an event callback can
11891         overwrite any current pending exception in the current application thread.
11892         Care must be taken to preserve a pending exception
11893         when an event callback makes a JNI call that might generate an exception.
11894       </li>
11895       <li>Event callback functions must be re-entrant. The <jvmti/> implementation does
11896         not queue events. If an agent needs to process events one at a time, it
11897         can use a raw monitor inside the
11898         event callback functions to serialize event processing.
11899       </li>
11900       <li>Event callback functions that execute JNI's FindClass function to load
11901         classes need to note that FindClass locates the class loader associated
11902         with the current native method. For the purposes of class loading, an
11903         event callback that includes a JNI environment as a parameter to the
11904         callback will treated as if it is a native call, where the native method
11905         is in the class of the event thread's current frame.
11906       </li>
11907     </ul>
11908     <p/>
11909     Some <jvmti/> events identify objects with JNI references.
11910     All references
11911     in <jvmti/> events are JNI local references and will become invalid
11912     after the event callback returns.
11913     Unless stated otherwise, memory referenced by pointers sent in event
11914     callbacks may not be referenced after the event callback returns.
11915     <p/>
11916     Except where stated otherwise, events are delivered on the thread
11917     that caused the event.
11918     Events are sent at the time they occur.
11919     The specification for each event includes the set of
11920     <functionlink id="GetPhase">phases</functionlink> in which it can be sent;
11921     if an event triggering activity occurs during another phase, no event
11922     is sent.
11923     <p/>
11924     A thread that generates an event does not change its execution status
11925     (for example, the event does not cause the thread to be suspended).
11926     If an agent wishes the event to result in suspension, then the agent
11927     is responsible for explicitly suspending the thread with
11928     <functionlink id="SuspendThread"></functionlink>.
11929     <p/>
11930     If an event is enabled in multiple environments, the event will be sent
11931     to each agent in the order that the environments were created.
11932   </intro>
11933 
11934   <intro label="Enabling Events" id="enablingevents">
11935     All events are initially disabled.  In order to receive any
11936     event:
11937       <ul>
11938         <li>
11939           If the event requires a capability, that capability must
11940           be added with
11941           <functionlink id="AddCapabilities"></functionlink>.
11942         </li>
11943         <li>
11944           A callback for the event must be set with
11945           <functionlink id="SetEventCallbacks"></functionlink>.
11946         </li>
11947         <li>
11948           The event must be enabled with
11949           <functionlink id="SetEventNotificationMode"></functionlink>.
11950         </li>
11951       </ul>
11952   </intro>
11953 
11954   <intro label="Multiple Co-located Events" id="eventorder">
11955     In many situations it is possible for multiple events to occur
11956     at the same location in one thread. When this happens, all the events
11957     are reported through the event callbacks in the order specified in this section.
11958     <p/>
11959     If the current location is at the entry point of a method, the
11960     <eventlink id="MethodEntry"></eventlink> event is reported before
11961     any other event at the current location in the same thread.
11962     <p/>
11963     If an exception catch has been detected at the current location,
11964     either because it is the beginning of a catch clause or a native method
11965     that cleared a pending exception has returned, the
11966     <code>exceptionCatch</code> event is reported before
11967     any other event at the current location in the same thread.
11968     <p/>
11969     If a <code>singleStep</code> event or
11970     <code>breakpoint</code> event is triggered at the
11971     current location, the event is defined to occur
11972     immediately before the code at the current location is executed.
11973     These events are reported before any events which are triggered
11974     by the execution of code at the current location in the same
11975     thread (specifically:
11976     <code>exception</code>,
11977     <code>fieldAccess</code>, and
11978     <code>fieldModification</code>).
11979     If both a step and breakpoint event are triggered for the same thread and
11980     location, the step event is reported before the breakpoint event.
11981     <p/>
11982     If the current location is the exit point of a method (that is, the last
11983     location before returning to the caller), the
11984     <eventlink id="MethodExit"></eventlink> event and
11985     the <eventlink id="FramePop"></eventlink> event (if requested)
11986     are reported after all other events at the current location in the same
11987     thread. There is no specified ordering of these two events
11988     with respect to each other.
11989     <p/>
11990     Co-located events can be triggered during the processing of some other
11991     event by the agent at the same location in the same thread.
11992     If such an event, of type <i>y</i>, is triggered during the processing of
11993     an event of type <i>x</i>, and if <i>x</i>
11994     precedes <i>y</i> in the ordering specified above, the co-located event
11995     <i>y</i> is reported for the current thread and location. If <i>x</i> does not precede
11996     <i>y</i>, <i>y</i> is not reported for the current thread and location.
11997     For example, if a breakpoint is set at the current location
11998     during the processing of <eventlink id="SingleStep"></eventlink>,
11999     that breakpoint will be reported before the thread moves off the current
12000     location.
12001     <p/>The following events are never considered to be co-located with
12002     other events.
12003     <ul>
12004       <li><eventlink id="VMStart"></eventlink></li>
12005       <li><eventlink id="VMInit"></eventlink></li>
12006       <li><eventlink id="VMDeath"></eventlink></li>
12007       <li><eventlink id="ThreadStart"></eventlink></li>
12008       <li><eventlink id="ThreadEnd"></eventlink></li>
12009       <li><eventlink id="ClassLoad"></eventlink></li>
12010       <li><eventlink id="ClassPrepare"></eventlink></li>
12011     </ul>
12012   </intro>
12013 
12014   <intro label="Event Callbacks" id="jvmtiEventCallbacks">
12015       The event callback structure below is used to specify the handler function
12016       for events.  It is set with the
12017       <functionlink id="SetEventCallbacks"></functionlink> function.
12018   </intro>
12019 
12020   <event label="Single Step"
12021          id="SingleStep" const="JVMTI_EVENT_SINGLE_STEP" filtered="thread" num="60">
12022     <description>
12023       Single step events allow the agent to trace thread execution
12024       at the finest granularity allowed by the VM. A single step event is
12025       generated whenever a thread reaches a new location.
12026       Typically, single step events represent the completion of one VM
12027       instruction as defined in <vmspec/>. However, some implementations
12028       may define locations differently. In any case the
12029       <code>method</code> and <code>location</code>
12030       parameters  uniquely identify the current location and allow
12031       the mapping to source file and line number when that information is
12032       available.
12033       <p/>
12034       No single step events are generated from within native methods.
12035     </description>
12036     <origin>jvmdi</origin>
12037     <capabilities>
12038       <required id="can_generate_single_step_events"></required>
12039     </capabilities>
12040     <parameters>
12041       <param id="jni_env">
12042         <outptr>
12043           <struct>JNIEnv</struct>
12044         </outptr>
12045           <description>
12046             The JNI environment of the event (current) thread
12047           </description>
12048       </param>
12049       <param id="thread">
12050         <jthread/>
12051           <description>
12052             Thread about to execution a new instruction
12053           </description>
12054       </param>
12055       <param id="klass">
12056         <jclass method="method"/>
12057           <description>
12058             Class of the method about to execute a new instruction
12059           </description>
12060       </param>
12061       <param id="method">
12062         <jmethodID class="klass"/>
12063           <description>
12064             Method about to execute a new instruction
12065           </description>
12066       </param>
12067       <param id="location">
12068         <jlocation/>
12069         <description>
12070           Location of the new instruction
12071         </description>
12072       </param>
12073     </parameters>
12074   </event>
12075 
12076   <event label="Breakpoint"
12077          id="Breakpoint" const="JVMTI_EVENT_BREAKPOINT" filtered="thread" num="62">
12078     <description>
12079       Breakpoint events are generated whenever a thread reaches a location
12080       designated as a breakpoint with <functionlink id="SetBreakpoint"></functionlink>.
12081       The <code>method</code> and <code>location</code>
12082       parameters uniquely identify the current location and allow
12083       the mapping to source file and line number when that information is
12084       available.
12085     </description>
12086     <origin>jvmdi</origin>
12087     <capabilities>
12088       <required id="can_generate_breakpoint_events"></required>
12089     </capabilities>
12090     <parameters>
12091       <param id="jni_env">
12092         <outptr>
12093           <struct>JNIEnv</struct>
12094         </outptr>
12095           <description>
12096             The JNI environment of the event (current) thread.
12097           </description>
12098       </param>
12099       <param id="thread">
12100         <jthread/>
12101           <description>
12102             Thread that hit the breakpoint
12103           </description>
12104       </param>
12105       <param id="klass">
12106         <jclass method="method"/>
12107           <description>
12108             Class of the method that hit the breakpoint
12109           </description>
12110       </param>
12111       <param id="method">
12112         <jmethodID class="klass"/>
12113           <description>
12114             Method that hit the breakpoint
12115           </description>
12116       </param>
12117       <param id="location">
12118         <jlocation/>
12119         <description>
12120           location of the breakpoint
12121         </description>
12122       </param>
12123     </parameters>
12124   </event>
12125 
12126   <event label="Field Access"
12127          id="FieldAccess" const="JVMTI_EVENT_FIELD_ACCESS" filtered="thread" num="63">
12128     <description>
12129       Field access events are generated whenever a thread accesses
12130       a field that was designated as a watchpoint
12131       with <functionlink id="SetFieldAccessWatch"></functionlink>.
12132       The <code>method</code> and <code>location</code>
12133       parameters uniquely identify the current location and allow
12134       the mapping to source file and line number when that information is
12135       available.
12136     </description>
12137     <origin>jvmdi</origin>
12138     <capabilities>
12139       <required id="can_generate_field_access_events"></required>
12140     </capabilities>
12141     <parameters>
12142       <param id="jni_env">
12143         <outptr>
12144           <struct>JNIEnv</struct>
12145         </outptr>
12146           <description>
12147             The JNI environment of the event (current) thread
12148           </description>
12149       </param>
12150       <param id="thread">
12151         <jthread/>
12152           <description>
12153             Thread accessing the field
12154           </description>
12155       </param>
12156       <param id="klass">
12157         <jclass method="method"/>
12158           <description>
12159             Class of the method where the access is occurring
12160           </description>
12161       </param>
12162       <param id="method">
12163         <jmethodID class="klass"/>
12164           <description>
12165             Method where the access is occurring
12166           </description>
12167       </param>
12168       <param id="location">
12169         <jlocation/>
12170         <description>
12171           Location where the access is occurring
12172         </description>
12173       </param>
12174       <param id="field_klass">
12175         <jclass field="field"/>
12176           <description>
12177             Class of the field being accessed
12178           </description>
12179       </param>
12180       <param id="object">
12181         <jobject/>
12182           <description>
12183             Object with the field being accessed if the field is an
12184             instance field; <code>NULL</code> otherwise
12185           </description>
12186       </param>
12187       <param id="field">
12188         <jfieldID class="field_klass"/>
12189           <description>
12190             Field being accessed
12191           </description>
12192       </param>
12193     </parameters>
12194   </event>
12195 
12196   <event label="Field Modification"
12197          id="FieldModification" const="JVMTI_EVENT_FIELD_MODIFICATION" filtered="thread" num="64">
12198     <description>
12199       Field modification events are generated whenever a thread modifies
12200       a field that was designated as a watchpoint
12201       with <functionlink id="SetFieldModificationWatch"></functionlink>.
12202       The <code>method</code> and <code>location</code>
12203       parameters uniquely identify the current location and allow
12204       the mapping to source file and line number when that information is
12205       available.
12206     </description>
12207     <origin>jvmdi</origin>
12208     <capabilities>
12209       <required id="can_generate_field_modification_events"></required>
12210     </capabilities>
12211     <parameters>
12212       <param id="jni_env">
12213         <outptr>
12214           <struct>JNIEnv</struct>
12215         </outptr>
12216           <description>
12217             The JNI environment of the event (current) thread
12218           </description>
12219       </param>
12220       <param id="thread">
12221         <jthread/>
12222           <description>
12223             Thread modifying the field
12224           </description>
12225       </param>
12226       <param id="klass">
12227         <jclass method="method"/>
12228           <description>
12229             Class of the method where the modification is occurring
12230           </description>
12231       </param>
12232       <param id="method">
12233         <jmethodID class="klass"/>
12234           <description>
12235             Method where the modification is occurring
12236           </description>
12237       </param>
12238       <param id="location">
12239         <jlocation/>
12240         <description>
12241           Location where the modification is occurring
12242         </description>
12243       </param>
12244       <param id="field_klass">
12245         <jclass field="field"/>
12246           <description>
12247             Class of the field being modified
12248           </description>
12249       </param>
12250       <param id="object">
12251         <jobject/>
12252           <description>
12253             Object with the field being modified if the field is an
12254             instance field; <code>NULL</code> otherwise
12255           </description>
12256       </param>
12257       <param id="field">
12258         <jfieldID class="field_klass"/>
12259           <description>
12260             Field being modified
12261           </description>
12262       </param>
12263       <param id="signature_type">
12264         <char/>
12265         <description>
12266           Signature type of the new value
12267         </description>
12268       </param>
12269       <param id="new_value">
12270         <jvalue/>
12271         <description>
12272           The new value
12273         </description>
12274       </param>
12275     </parameters>
12276   </event>
12277 
12278   <event label="Frame Pop"
12279          id="FramePop" const="JVMTI_EVENT_FRAME_POP" filtered="thread" num="61">
12280     <description>
12281       Frame pop events are generated upon exit from a single method
12282       in a single frame as specified
12283       in a call to <functionlink id="NotifyFramePop"></functionlink>.
12284       This is true whether termination is caused by
12285       executing its return instruction
12286       or by throwing an exception to its caller
12287       (see <paramlink id="was_popped_by_exception"></paramlink>).
12288       However, frame pops caused by the <functionlink id="PopFrame"/>
12289       function are not reported.
12290       <p/>
12291       The location reported by <functionlink id="GetFrameLocation"></functionlink>
12292       for the depth 0 identifies the executable location in the returning method,
12293       immediately prior to the return.
12294     </description>
12295     <origin>jvmdi</origin>
12296     <capabilities>
12297       <required id="can_generate_frame_pop_events"></required>
12298     </capabilities>
12299     <parameters>
12300       <param id="jni_env">
12301         <outptr>
12302           <struct>JNIEnv</struct>
12303         </outptr>
12304           <description>
12305             The JNI environment of the event (current) thread
12306           </description>
12307       </param>
12308       <param id="thread">
12309         <jthread/>
12310           <description>
12311             Thread that is popping the frame
12312           </description>
12313       </param>
12314       <param id="klass">
12315         <jclass method="method"/>
12316           <description>
12317             Class of the method being popped
12318           </description>
12319       </param>
12320       <param id="method">
12321         <jmethodID class="klass"/>
12322           <description>
12323             Method being popped
12324           </description>
12325       </param>
12326       <param id="was_popped_by_exception">
12327         <jboolean/>
12328         <description>
12329           True if frame was popped by a thrown exception.
12330           False if method exited through its return instruction.
12331         </description>
12332       </param>
12333     </parameters>
12334   </event>
12335 
12336   <event label="Method Entry"
12337          id="MethodEntry" const="JVMTI_EVENT_METHOD_ENTRY" filtered="thread" num="65">
12338     <description>
12339       Method entry events are generated upon entry of Java
12340       programming language methods (including native methods).
12341       <p/>
12342       The location reported by <functionlink id="GetFrameLocation"></functionlink>
12343       for the depth 0 identifies the initial executable location in the method.
12344       <p/>
12345       Enabling method
12346       entry or exit events will significantly degrade performance on many platforms and is thus
12347       not advised for performance critical usage (such as profiling).
12348       <internallink id="bci">Bytecode instrumentation</internallink> should be
12349       used in these cases.
12350     </description>
12351     <origin>jvmdi</origin>
12352     <capabilities>
12353       <required id="can_generate_method_entry_events"></required>
12354     </capabilities>
12355     <parameters>
12356       <param id="jni_env">
12357         <outptr>
12358           <struct>JNIEnv</struct>
12359         </outptr>
12360           <description>
12361             The JNI environment of the event (current) thread
12362           </description>
12363       </param>
12364       <param id="thread">
12365         <jthread/>
12366           <description>
12367             Thread entering the method
12368           </description>
12369       </param>
12370       <param id="klass">
12371         <jclass method="method"/>
12372           <description>
12373             Class of the method being entered
12374           </description>
12375       </param>
12376       <param id="method">
12377         <jmethodID class="klass"/>
12378           <description>
12379             Method being entered
12380           </description>
12381       </param>
12382     </parameters>
12383   </event>
12384 
12385   <event label="Method Exit"
12386          id="MethodExit" const="JVMTI_EVENT_METHOD_EXIT" filtered="thread" num="66">
12387     <description>
12388       Method exit events are generated upon exit from Java
12389       programming language methods (including native methods).
12390       This is true whether termination is caused by
12391       executing its return instruction
12392       or by throwing an exception to its caller
12393       (see <paramlink id="was_popped_by_exception"></paramlink>).
12394       <p/>
12395       The location reported by <functionlink id="GetFrameLocation"></functionlink>
12396       for the depth 0 identifies the executable location in the returning method
12397       immediately prior to the return.
12398       <p/>
12399         Enabling method
12400         entry or exit events will significantly degrade performance on many platforms and is thus
12401         not advised for performance critical usage (such as profiling).
12402         <internallink id="bci">Bytecode instrumentation</internallink> should be
12403         used in these cases.
12404     </description>
12405     <origin>jvmdi</origin>
12406     <capabilities>
12407       <required id="can_generate_method_exit_events"></required>
12408     </capabilities>
12409     <parameters>
12410       <param id="jni_env">
12411         <outptr>
12412           <struct>JNIEnv</struct>
12413         </outptr>
12414           <description>
12415             The JNI environment of the event (current) thread
12416           </description>
12417       </param>
12418       <param id="thread">
12419         <jthread/>
12420           <description>
12421             Thread exiting the method
12422           </description>
12423       </param>
12424       <param id="klass">
12425         <jclass method="method"/>
12426           <description>
12427             Class of the method being exited
12428           </description>
12429       </param>
12430       <param id="method">
12431         <jmethodID class="klass"/>
12432           <description>
12433             Method being exited
12434           </description>
12435       </param>
12436       <param id="was_popped_by_exception">
12437         <jboolean/>
12438         <description>
12439           True if frame was popped by a thrown exception.
12440           False if method exited through its return instruction.
12441         </description>
12442       </param>
12443       <param id="return_value">
12444         <jvalue/>
12445         <description>
12446           The return value of the method being exited.
12447           Undefined and should not be used if
12448           <paramlink id="was_popped_by_exception"></paramlink>
12449           is true.
12450         </description>
12451       </param>
12452     </parameters>
12453   </event>
12454 
12455   <event label="Native Method Bind" phase="any"
12456          id="NativeMethodBind" const="JVMTI_EVENT_NATIVE_METHOD_BIND" num="67">
12457     <description>
12458       A Native Method Bind event is sent when a VM binds a
12459       Java programming language native method
12460       to the address of a function that implements the native method.
12461       This will occur when the native method is called for the first time
12462       and also occurs when the JNI function <code>RegisterNatives</code> is called.
12463       This event allows the bind to be redirected to an agent-specified
12464       proxy function.
12465       This event is not sent when the native method is unbound.
12466       Typically, this proxy function will need to be specific to a
12467       particular method or, to handle the general case, automatically
12468       generated assembly code, since after instrumentation code is
12469       executed the function at the original binding
12470       address will usually be invoked.
12471       The original binding can be restored or the redirection changed
12472       by use of the JNI function <code>RegisterNatives</code>.
12473       Some events may be sent during the primordial phase, JNI and
12474       most of <jvmti/> cannot be used at this time but the method and
12475       address can be saved for use later.
12476     </description>
12477     <origin>new</origin>
12478     <capabilities>
12479       <required id="can_generate_native_method_bind_events"></required>
12480     </capabilities>
12481     <parameters>
12482       <param id="jni_env">
12483         <outptr>
12484           <struct>JNIEnv</struct>
12485         </outptr>
12486           <description>
12487             The JNI environment of the event (current) thread
12488             Will be <code>NULL</code> if sent during the primordial
12489             <functionlink id="GetPhase">phase</functionlink>.
12490           </description>
12491       </param>
12492       <param id="thread">
12493         <jthread/>
12494           <description>
12495             Thread requesting the bind
12496           </description>
12497       </param>
12498       <param id="klass">
12499         <jclass method="method"/>
12500           <description>
12501             Class of the method being bound
12502           </description>
12503       </param>
12504       <param id="method">
12505         <jmethodID class="klass"/>
12506           <description>
12507             Native method being bound
12508           </description>
12509       </param>
12510       <param id="address">
12511         <outptr><void/></outptr>
12512         <description>
12513           The address the VM is about to bind to--that is, the
12514           address of the implementation of the native method
12515         </description>
12516       </param>
12517       <param id="new_address_ptr">
12518         <agentbuf><void/></agentbuf>
12519         <description>
12520           if the referenced address is changed (that is, if
12521           <code>*new_address_ptr</code> is set), the binding
12522           will instead be made to the supplied address.
12523         </description>
12524       </param>
12525     </parameters>
12526   </event>
12527 
12528   <event label="Exception"
12529          id="Exception" const="JVMTI_EVENT_EXCEPTION" filtered="thread" num="58">
12530     <description>
12531       Exception events are generated whenever an exception is first detected
12532       in a Java programming language method.
12533       Where "exception" means any <code>java.lang.Throwable</code>.
12534       The exception may have been thrown by a Java programming language or native
12535       method, but in the case of native methods, the event is not generated
12536       until the exception is first seen by a Java programming language method. If an exception is
12537       set and cleared in a native method (and thus is never visible to Java programming language code),
12538       no exception event is generated.
12539       <p/>
12540       The <code>method</code> and <code>location</code>
12541       parameters  uniquely identify the current location
12542       (where the exception was detected) and allow
12543       the mapping to source file and line number when that information is
12544       available. The <code>exception</code> field identifies the thrown
12545       exception object. The <code>catch_method</code>
12546       and <code>catch_location</code> identify the location of the catch clause,
12547       if any, that handles the thrown exception. If there is no such catch clause,
12548       each field is set to 0. There is no guarantee that the thread will ever
12549       reach this catch clause. If there are native methods on the call stack
12550       between the throw location and the catch clause, the exception may
12551       be reset by one of those native methods.
12552       Similarly, exceptions that are reported as uncaught (<code>catch_klass</code>
12553       et al. set to 0) may in fact be caught by native code.
12554       Agents can check for these occurrences by monitoring
12555       <eventlink id="ExceptionCatch"></eventlink> events.
12556       Note that finally clauses are implemented as catch and re-throw. Therefore they
12557       will be reported in the catch location.
12558     </description>
12559     <origin>jvmdi</origin>
12560     <capabilities>
12561       <required id="can_generate_exception_events"></required>
12562     </capabilities>
12563     <parameters>
12564       <param id="jni_env">
12565         <outptr>
12566           <struct>JNIEnv</struct>
12567         </outptr>
12568           <description>
12569             The JNI environment of the event (current) thread
12570           </description>
12571       </param>
12572       <param id="thread">
12573         <jthread/>
12574           <description>
12575             Thread generating the exception
12576           </description>
12577       </param>
12578       <param id="klass">
12579         <jclass method="method"/>
12580           <description>
12581             Class generating the exception
12582           </description>
12583       </param>
12584       <param id="method">
12585         <jmethodID class="klass"/>
12586           <description>
12587             Method generating the exception
12588           </description>
12589       </param>
12590       <param id="location">
12591         <jlocation/>
12592         <description>
12593           Location where exception occurred
12594         </description>
12595       </param>
12596       <param id="exception">
12597         <jobject/>
12598           <description>
12599             The exception being thrown
12600           </description>
12601       </param>
12602       <param id="catch_klass">
12603         <jclass method="catch_method"/>
12604           <description>
12605             Class that will catch the exception, or <code>NULL</code> if no known catch
12606           </description>
12607       </param>
12608       <param id="catch_method">
12609         <jmethodID class="catch_klass"/>
12610           <description>
12611             Method that will catch the exception, or <code>NULL</code> if no known catch
12612           </description>
12613       </param>
12614       <param id="catch_location">
12615         <jlocation/>
12616         <description>
12617           location which will catch the exception or zero if no known catch
12618         </description>
12619       </param>
12620     </parameters>
12621   </event>
12622 
12623   <event label="Exception Catch"
12624          id="ExceptionCatch" const="JVMTI_EVENT_EXCEPTION_CATCH" filtered="thread" num="59">
12625     <description>
12626       Exception catch events are generated whenever a thrown exception is caught.
12627       Where "exception" means any <code>java.lang.Throwable</code>.
12628       If the exception is caught in a Java programming language method, the event is generated
12629       when the catch clause is reached. If the exception is caught in a native
12630       method, the event is generated as soon as control is returned to a Java programming language
12631       method. Exception catch events are generated for any exception for which
12632       a throw was detected in a Java programming language method.
12633       Note that finally clauses are implemented as catch and re-throw. Therefore they
12634       will generate exception catch events.
12635       <p/>
12636       The <code>method</code> and <code>location</code>
12637       parameters uniquely identify the current location
12638       and allow the mapping to source file and line number when that information is
12639       available. For exceptions caught in a Java programming language method, the
12640       <code>exception</code> object identifies the exception object. Exceptions
12641       caught in native methods are not necessarily available by the time the
12642       exception catch is reported, so the <code>exception</code> field is set
12643       to <code>NULL</code>.
12644     </description>
12645     <origin>jvmdi</origin>
12646     <capabilities>
12647       <required id="can_generate_exception_events"></required>
12648     </capabilities>
12649     <parameters>
12650       <param id="jni_env">
12651         <outptr>
12652           <struct>JNIEnv</struct>
12653         </outptr>
12654           <description>
12655             The JNI environment of the event (current) thread
12656           </description>
12657       </param>
12658       <param id="thread">
12659         <jthread/>
12660           <description>
12661             Thread catching the exception
12662           </description>
12663       </param>
12664       <param id="klass">
12665         <jclass method="method"/>
12666           <description>
12667             Class catching the exception
12668           </description>
12669       </param>
12670       <param id="method">
12671         <jmethodID class="klass"/>
12672           <description>
12673             Method catching the exception
12674           </description>
12675       </param>
12676       <param id="location">
12677         <jlocation/>
12678         <description>
12679           Location where exception is being caught
12680         </description>
12681       </param>
12682       <param id="exception">
12683         <jobject/>
12684           <description>
12685             Exception being caught
12686           </description>
12687       </param>
12688     </parameters>
12689   </event>
12690 
12691   <event label="Thread Start"
12692          id="ThreadStart" const="JVMTI_EVENT_THREAD_START" num="52" phase="start">
12693     <description>
12694       Thread start events are generated by a new thread before its initial
12695       method executes.
12696       <p/>
12697       A thread may be listed in the array returned by
12698       <functionlink id="GetAllThreads"></functionlink>
12699       before its thread start event is generated.
12700       It is possible for other events to be generated
12701       on a thread before its thread start event.
12702       <p/>
12703       The event is sent on the newly started <paramlink id="thread"></paramlink>.
12704     </description>
12705     <origin>jvmdi</origin>
12706     <capabilities>
12707     </capabilities>
12708     <parameters>
12709       <param id="jni_env">
12710         <outptr>
12711           <struct>JNIEnv</struct>
12712         </outptr>
12713           <description>
12714             The JNI environment of the event (current) thread.
12715           </description>
12716       </param>
12717       <param id="thread">
12718         <jthread/>
12719           <description>
12720             Thread starting
12721           </description>
12722       </param>
12723     </parameters>
12724   </event>
12725 
12726   <event label="Thread End"
12727          id="ThreadEnd" const="JVMTI_EVENT_THREAD_END" filtered="thread" num="53" phase="start">
12728     <description>
12729       Thread end events are generated by a terminating thread
12730       after its initial method has finished execution.
12731       <p/>
12732       A thread may be listed in the array returned by
12733       <functionlink id="GetAllThreads"></functionlink>
12734       after its thread end event is generated.
12735       No events are generated on a thread
12736       after its thread end event.
12737       <p/>
12738       The event is sent on the dying <paramlink id="thread"></paramlink>.
12739     </description>
12740     <origin>jvmdi</origin>
12741     <capabilities>
12742     </capabilities>
12743     <parameters>
12744       <param id="jni_env">
12745         <outptr>
12746           <struct>JNIEnv</struct>
12747         </outptr>
12748           <description>
12749             The JNI environment of the event (current) thread.
12750           </description>
12751       </param>
12752       <param id="thread">
12753         <jthread/>
12754           <description>
12755             Thread ending
12756           </description>
12757       </param>
12758     </parameters>
12759   </event>
12760 
12761   <event label="Class Load"
12762          id="ClassLoad" const="JVMTI_EVENT_CLASS_LOAD" filtered="thread" phase="start" num="55">
12763     <description>
12764       A class load event is generated
12765       <functionlink id="GetLoadedClasses">when a class or interface is created.</functionlink>.
12766       <p/>
12767       Array class creation does not generate a class load event.
12768       The creation of a primitive class (for example, java.lang.Integer.TYPE)
12769       does not generate a class load event.
12770       <p/>
12771       The order of class load events generated by a particular thread is guaranteed
12772       to match the order of class loading within that thread.
12773       <p/>
12774       This event is sent at an early stage in loading the class. As
12775       a result the class should be used carefully.  Note, for example,
12776       that methods and fields are not yet loaded, so queries for methods,
12777       fields, subclasses, and so on will not give correct results.
12778       See "Loading of Classes and Interfaces" in the <i>Java Language
12779       Specification</i>.  For most
12780       purposes the <eventlink id="ClassPrepare"></eventlink> event will
12781       be more useful.
12782     </description>
12783     <origin>jvmdi</origin>
12784     <capabilities>
12785     </capabilities>
12786     <parameters>
12787       <param id="jni_env">
12788         <outptr>
12789           <struct>JNIEnv</struct>
12790         </outptr>
12791           <description>
12792             The JNI environment of the event (current) thread
12793           </description>
12794       </param>
12795       <param id="thread">
12796         <jthread/>
12797           <description>
12798             Thread loading the class
12799           </description>
12800       </param>
12801       <param id="klass">
12802         <jclass/>
12803           <description>
12804             Class being loaded
12805           </description>
12806       </param>
12807     </parameters>
12808   </event>
12809 
12810   <elide>
12811   <event label="Class Unload"
12812          id="ClassUnload" const="JVMTI_EVENT_CLASS_UNLOAD" num="57">
12813     <description>
12814       A class unload event is generated when the class is about to be unloaded.
12815       Class unload events take place during garbage collection and must be
12816       handled extremely carefully. The garbage collector holds many locks
12817       and has suspended all other threads, so the event handler cannot depend
12818       on the ability to acquire any locks. The class unload event handler should
12819       do as little as possible, perhaps by queuing information to be processed
12820       later.  In particular, the <code>jclass</code> should be used only in
12821       the JNI function <code>isSameObject</code> or in the following <jvmti/> functions:
12822       <ul>
12823         <li><functionlink id="GetClassSignature"></functionlink></li>
12824         <li><functionlink id="GetSourceFileName"></functionlink></li>
12825         <li><functionlink id="IsInterface"></functionlink></li>
12826         <li><functionlink id="IsArrayClass"></functionlink></li>
12827       </ul>
12828     </description>
12829     <origin>jvmdi</origin>
12830     <capabilities>
12831     </capabilities>
12832     <parameters>
12833       <param id="jni_env">
12834         <outptr>
12835           <struct>JNIEnv</struct>
12836         </outptr>
12837           <description>
12838             The JNI environment of the event (current) thread
12839           </description>
12840       </param>
12841       <param id="thread">
12842         <jthread/>
12843           <description>
12844             Thread generating the class unload
12845           </description>
12846       </param>
12847       <param id="klass">
12848         <jclass/>
12849           <description>
12850             Class being unloaded
12851           </description>
12852       </param>
12853     </parameters>
12854   </event>
12855   </elide>
12856 
12857   <event label="Class Prepare"
12858          id="ClassPrepare" const="JVMTI_EVENT_CLASS_PREPARE" filtered="thread" phase="start" num="56">
12859     <description>
12860       A class prepare event is generated when class preparation is complete.
12861       At this point, class fields, methods, and implemented interfaces are
12862       available, and no code from the class has been executed. Since array
12863       classes never have fields or methods, class prepare events are not
12864       generated for them. Class prepare events are not generated for
12865       primitive classes (for example, <code>java.lang.Integer.TYPE</code>).
12866     </description>
12867     <origin>jvmdi</origin>
12868     <capabilities>
12869     </capabilities>
12870     <parameters>
12871       <param id="jni_env">
12872         <outptr>
12873           <struct>JNIEnv</struct>
12874         </outptr>
12875           <description>
12876             The JNI environment of the event (current) thread
12877           </description>
12878       </param>
12879       <param id="thread">
12880         <jthread/>
12881           <description>
12882             Thread generating the class prepare
12883           </description>
12884       </param>
12885       <param id="klass">
12886         <jclass/>
12887           <description>
12888             Class being prepared
12889           </description>
12890       </param>
12891     </parameters>
12892   </event>
12893 
12894   <event label="Class File Load Hook" phase="any"
12895          id="ClassFileLoadHook" const="JVMTI_EVENT_CLASS_FILE_LOAD_HOOK" num="54">
12896     <description>
12897       This event is sent when the VM obtains class file data,
12898       but before it constructs
12899       the in-memory representation for that class.
12900       This event is also sent when the class is being modified by the
12901       <functionlink id="RetransformClasses"/> function or
12902       the <functionlink id="RedefineClasses"/> function,
12903       called in any <jvmti/> environment.
12904       The agent can instrument
12905       the existing class file data sent by the VM to include profiling/debugging hooks.
12906       See the description of
12907       <internallink id="bci">bytecode instrumentation</internallink>
12908       for usage information.
12909       <p/>
12910     When the capabilities
12911     <internallink id="jvmtiCapabilities.can_generate_early_class_hook_events">
12912     <code>can_generate_early_class_hook_events</code></internallink> and
12913     <internallink id="jvmtiCapabilities.can_generate_all_class_hook_events">
12914     <code>can_generate_all_class_hook_events</code></internallink>
12915     are enabled then this event may be sent in the primordial phase.
12916     Otherwise, this event may be sent before the VM is initialized (the start
12917     <functionlink id="GetPhase">phase</functionlink>).
12918     Some classes might not be compatible
12919     with the function (eg. ROMized classes or implementation defined classes) and this event will
12920     not be generated for these classes.
12921     <p/>
12922     The agent must allocate the space for the modified
12923     class file data buffer
12924     using the memory allocation function
12925     <functionlink id="Allocate"></functionlink> because the
12926     VM is responsible for freeing the new class file data buffer
12927     using <functionlink id="Deallocate"></functionlink>.
12928     <p/>
12929     If the agent wishes to modify the class file, it must set
12930     <code>new_class_data</code> to point
12931     to the newly instrumented class file data buffer and set
12932     <code>new_class_data_len</code> to the length of that
12933     buffer before returning
12934     from this call.  If no modification is desired, the agent simply
12935     does not set <code>new_class_data</code>.  If multiple agents
12936     have enabled this event the results are chained. That is, if
12937     <code>new_class_data</code> has been set, it becomes the
12938     <code>class_data</code> for the next agent.
12939     <p/>
12940     When handling a class load in the live phase, then the
12941     <functionlink id="GetNamedModule"></functionlink>
12942     function can be used to map class loader and a package name to a module.
12943     When a class is being redefined or retransformed then
12944     <code>class_being_redefined</code> is non <code>NULL</code> and so
12945     the JNI <code>GetModule</code> function can also be used
12946     to obtain the Module.
12947     <p/>
12948     The order that this event is sent to each environment differs
12949     from other events.
12950     This event is sent to environments in the following order:
12951     <ul>
12952       <li><fieldlink id="can_retransform_classes"
12953                      struct="jvmtiCapabilities">retransformation
12954                                                 incapable</fieldlink>
12955           environments, in the
12956           order in which they were created
12957       </li>
12958       <li><fieldlink id="can_retransform_classes"
12959                      struct="jvmtiCapabilities">retransformation
12960                                                 capable</fieldlink>
12961           environments, in the
12962           order in which they were created
12963       </li>
12964     </ul>
12965     When triggered by <functionlink id="RetransformClasses"/>,
12966     this event is sent only to <fieldlink id="can_retransform_classes"
12967                      struct="jvmtiCapabilities">retransformation
12968                                                 capable</fieldlink>
12969     environments.
12970   </description>
12971   <origin>jvmpi</origin>
12972     <capabilities>
12973       <capability id="can_generate_all_class_hook_events"></capability>
12974       <capability id="can_generate_early_class_hook_events"></capability>
12975     </capabilities>
12976     <parameters>
12977       <param id="jni_env">
12978         <outptr>
12979           <struct>JNIEnv</struct>
12980         </outptr>
12981           <description>
12982             The JNI environment of the event (current) thread.
12983           </description>
12984       </param>
12985       <param id="class_being_redefined">
12986         <jclass/>
12987         <description>
12988           The class being
12989           <functionlink id="RedefineClasses">redefined</functionlink> or
12990           <functionlink id="RetransformClasses">retransformed</functionlink>.
12991           <code>NULL</code> if sent by class load.
12992         </description>
12993       </param>
12994       <param id="loader">
12995         <jobject/>
12996           <description>
12997             The class loader loading the class.
12998             <code>NULL</code> if the bootstrap class loader.
12999           </description>
13000       </param>
13001       <param id="name">
13002         <vmbuf><char/></vmbuf>
13003         <description>
13004             Name of class being loaded as a VM internal qualified name
13005             (for example, "java/util/List"), encoded as a
13006             <internallink id="mUTF">modified UTF-8</internallink> string.
13007             Note: if the class is defined with a <code>NULL</code> name or
13008             without a name specified, <code>name</code> will be <code>NULL</code>.
13009         </description>
13010       </param>
13011       <param id="protection_domain">
13012         <jobject/>
13013         <description>
13014           The <code>ProtectionDomain</code> of the class.
13015         </description>
13016       </param>
13017       <param id="class_data_len">
13018         <jint/>
13019         <description>
13020           Length of current class file data buffer.
13021         </description>
13022       </param>
13023       <param id="class_data">
13024         <vmbuf><uchar/></vmbuf>
13025         <description>
13026           Pointer to the current class file data buffer.
13027         </description>
13028       </param>
13029       <param id="new_class_data_len">
13030         <outptr><jint/></outptr>
13031         <description>
13032           Pointer to the length of the new class file data buffer.
13033         </description>
13034       </param>
13035       <param id="new_class_data">
13036         <agentbuf incount="new_class_data_len"><uchar/></agentbuf>
13037         <description>
13038           Pointer to the pointer to the instrumented class file data buffer.
13039         </description>
13040       </param>
13041     </parameters>
13042   </event>
13043 
13044   <event label="VM Start Event"
13045          id="VMStart" const="JVMTI_EVENT_VM_START" num="57" phase="start">
13046     <description>
13047       The VM start event signals the start of the VM.
13048       At this time JNI is live but the VM is not yet fully initialized.
13049       Once this event is generated, the agent is free to call any JNI function.
13050       This event signals the beginning of the start phase,
13051       <jvmti/> functions permitted in the start phase may be called.
13052       <p/>
13053       The timing of this event may depend on whether the agent has added the
13054       <internallink id="jvmtiCapabilities.can_generate_early_vmstart">
13055       <code>can_generate_early_vmstart</code></internallink> capability or not.
13056       If the capability has been added then the VM posts the event as early
13057       as possible. The VM is capable of executing bytecode but it may not have
13058       initialized to the point where it can load classes in modules other than
13059       <code>java.base</code>, or even arbitrary classes in <code>java.base</code>.
13060       Agents that do load-time instrumentation in this
13061       phase must take great care when instrumenting code that potentially
13062       executes in this phase. Extreme care should also be taken with JNI
13063       <code>FindClass</code> as it may not be possible to load classes and attempts
13064       to do so may result in unpredictable behavior, maybe even stability issues
13065       on some VM implementations.
13066       If the capability has not been added then the VM delays posting this
13067       event until it is capable of loading classes in modules other than
13068       <code>java.base</code> or the VM has completed its initialization.
13069       Agents that create more than one JVM TI environment, where the
13070       capability is added to some but not all environments, may observe the
13071       start phase beginning earlier in the JVM TI environments that possess
13072       the capability.
13073       <p/>
13074       In the case of VM start-up failure, this event will not be sent.
13075     </description>
13076     <origin>jvmdi</origin>
13077     <capabilities>
13078     </capabilities>
13079     <parameters>
13080       <param id="jni_env">
13081         <outptr>
13082           <struct>JNIEnv</struct>
13083         </outptr>
13084           <description>
13085             The JNI environment of the event (current) thread.
13086           </description>
13087       </param>
13088     </parameters>
13089   </event>
13090 
13091   <event label="VM Initialization Event"
13092          id="VMInit" const="JVMTI_EVENT_VM_INIT" num="50">
13093     <description>
13094       The VM initialization event signals the completion of VM initialization. Once
13095       this event is generated, the agent is free to call any JNI or <jvmti/>
13096       function. The VM initialization event can be preceded by or can be concurrent
13097       with other events, but
13098       the preceding events should be handled carefully, if at all, because the
13099       VM has not completed its initialization. The thread start event for the
13100       main application thread is guaranteed not to occur until after the
13101       handler for the VM initialization event returns.
13102       <p/>
13103       In the case of VM start-up failure, this event will not be sent.
13104     </description>
13105     <origin>jvmdi</origin>
13106     <capabilities>
13107     </capabilities>
13108     <parameters>
13109       <param id="jni_env">
13110         <outptr>
13111           <struct>JNIEnv</struct>
13112         </outptr>
13113           <description>
13114             The JNI environment of the event (current) thread.
13115           </description>
13116       </param>
13117       <param id="thread">
13118         <jthread/>
13119           <description>
13120             The initial thread
13121           </description>
13122       </param>
13123     </parameters>
13124   </event>
13125 
13126   <event label="VM Death Event"
13127          id="VMDeath" const="JVMTI_EVENT_VM_DEATH" num="51">
13128     <description>
13129       The VM death event notifies the agent of the termination of the VM.
13130       No events will occur after the VMDeath event.
13131       <p/>
13132       In the case of VM start-up failure, this event will not be sent.
13133       Note that <internallink id="onunload">Agent_OnUnload</internallink>
13134       will still be called in these cases.
13135     </description>
13136     <origin>jvmdi</origin>
13137     <capabilities>
13138     </capabilities>
13139     <parameters>
13140       <param id="jni_env">
13141         <outptr>
13142           <struct>JNIEnv</struct>
13143         </outptr>
13144           <description>
13145             The JNI environment of the event (current) thread
13146           </description>
13147       </param>
13148     </parameters>
13149   </event>
13150 
13151   <event label="Compiled Method Load" phase="start"
13152          id="CompiledMethodLoad" const="JVMTI_EVENT_COMPILED_METHOD_LOAD" num="68">
13153     <description>
13154       Sent when a method is compiled and loaded into memory by the VM.
13155       If it is unloaded, the <eventlink id="CompiledMethodUnload"/> event is sent.
13156       If it is moved, the <eventlink id="CompiledMethodUnload"/> event is sent,
13157       followed by a new <code>CompiledMethodLoad</code> event.
13158       Note that a single method may have multiple compiled forms, and that
13159       this event will be sent for each form.
13160       Note also that several methods may be inlined into a single
13161       address range, and that this event will be sent for each method.
13162       <p/>
13163       These events can be sent after their initial occurrence with
13164       <functionlink id="GenerateEvents"></functionlink>.
13165     </description>
13166     <origin>jvmpi</origin>
13167     <typedef id="jvmtiAddrLocationMap" label="Native address to location entry">
13168       <field id="start_address">
13169         <vmbuf><void/></vmbuf>
13170         <description>
13171           Starting native address of code corresponding to a location
13172         </description>
13173       </field>
13174       <field id="location">
13175         <jlocation/>
13176         <description>
13177           Corresponding location. See
13178           <functionlink id="GetJLocationFormat"></functionlink>
13179           for the meaning of location.
13180         </description>
13181       </field>
13182     </typedef>
13183     <capabilities>
13184       <required id="can_generate_compiled_method_load_events"></required>
13185     </capabilities>
13186     <parameters>
13187       <param id="klass">
13188         <jclass method="method"/>
13189           <description>
13190             Class of the method being compiled and loaded
13191           </description>
13192       </param>
13193       <param id="method">
13194         <jmethodID class="klass"/>
13195           <description>
13196             Method being compiled and loaded
13197           </description>
13198       </param>
13199       <param id="code_size">
13200         <jint/>
13201         <description>
13202           Size of compiled code
13203         </description>
13204       </param>
13205       <param id="code_addr">
13206         <vmbuf><void/></vmbuf>
13207         <description>
13208           Address where compiled method code is loaded
13209         </description>
13210       </param>
13211       <param id="map_length">
13212         <jint/>
13213         <description>
13214           Number of <typelink id="jvmtiAddrLocationMap"></typelink>
13215           entries in the address map.
13216           Zero if mapping information cannot be supplied.
13217         </description>
13218       </param>
13219       <param id="map">
13220         <vmbuf><struct>jvmtiAddrLocationMap</struct></vmbuf>
13221         <description>
13222           Map from native addresses to location.
13223           The native address range of each entry is from
13224           <fieldlink id="start_address" struct="jvmtiAddrLocationMap"></fieldlink>
13225           to <code>start_address-1</code> of the next entry.
13226           <code>NULL</code> if mapping information cannot be supplied.
13227         </description>
13228       </param>
13229       <param id="compile_info">
13230         <vmbuf><void/></vmbuf>
13231         <description>
13232           VM-specific compilation information.
13233           The referenced compile information is managed by the VM
13234           and must not depend on the agent for collection.
13235           A VM implementation defines the content and lifetime
13236           of the information.
13237         </description>
13238       </param>
13239     </parameters>
13240   </event>
13241 
13242   <event label="Compiled Method Unload" phase="start"
13243          id="CompiledMethodUnload" const="JVMTI_EVENT_COMPILED_METHOD_UNLOAD" num="69">
13244     <description>
13245       Sent when a compiled method is unloaded from memory.
13246       This event might not be sent on the thread which performed the unload.
13247       This event may be sent sometime after the unload occurs, but
13248       will be sent before the memory is reused
13249       by a newly generated compiled method. This event may be sent after
13250       the class is unloaded.
13251     </description>
13252     <origin>jvmpi</origin>
13253     <capabilities>
13254       <required id="can_generate_compiled_method_load_events"></required>
13255     </capabilities>
13256     <parameters>
13257       <param id="klass">
13258         <jclass method="method"/>
13259           <description>
13260             Class of the compiled method being unloaded.
13261           </description>
13262       </param>
13263       <param id="method">
13264         <jmethodID class="klass"/>
13265           <description>
13266             Compiled method being unloaded.
13267             For identification of the compiled method only -- the class
13268             may be unloaded and therefore the method should not be used
13269             as an argument to further JNI or <jvmti/> functions.
13270           </description>
13271       </param>
13272       <param id="code_addr">
13273         <vmbuf><void/></vmbuf>
13274         <description>
13275           Address where compiled method code was loaded.
13276           For identification of the compiled method only --
13277           the space may have been reclaimed.
13278         </description>
13279       </param>
13280     </parameters>
13281   </event>
13282 
13283   <event label="Dynamic Code Generated" phase="any"
13284          id="DynamicCodeGenerated" const="JVMTI_EVENT_DYNAMIC_CODE_GENERATED" num="70">
13285     <description>
13286       Sent when a component of the virtual machine is generated dynamically.
13287       This does not correspond to Java programming language code that is
13288       compiled--see <eventlink id="CompiledMethodLoad"></eventlink>.
13289       This is for native code--for example, an interpreter that is generated
13290       differently depending on command-line options.
13291       <p/>
13292       Note that this event has no controlling capability.
13293       If a VM cannot generate these events, it simply does not send any.
13294       <p/>
13295       These events can be sent after their initial occurrence with
13296       <functionlink id="GenerateEvents"></functionlink>.
13297     </description>
13298     <origin>jvmpi</origin>
13299     <capabilities>
13300     </capabilities>
13301     <parameters>
13302       <param id="name">
13303         <vmbuf><char/></vmbuf>
13304         <description>
13305           Name of the code, encoded as a
13306           <internallink id="mUTF">modified UTF-8</internallink> string.
13307           Intended for display to an end-user.
13308           The name might not be unique.
13309         </description>
13310       </param>
13311       <param id="address">
13312         <vmbuf><void/></vmbuf>
13313         <description>
13314           Native address of the code
13315         </description>
13316       </param>
13317       <param id="length">
13318         <jint/>
13319         <description>
13320           Length in bytes of the code
13321         </description>
13322       </param>
13323     </parameters>
13324   </event>
13325 
13326   <event label="Data Dump Request"
13327          id="DataDumpRequest" const="JVMTI_EVENT_DATA_DUMP_REQUEST" num="71">
13328     <description>
13329       Sent by the VM to request the agent to dump its data.  This
13330       is just a hint and the agent need not react to this event.
13331       This is useful for processing command-line signals from users.  For
13332       example, in the Java 2 SDK a CTRL-Break on Win32 and a CTRL-\ on Linux
13333       causes the VM to send this event to the agent.
13334     </description>
13335     <origin>jvmpi</origin>
13336     <capabilities>
13337     </capabilities>
13338     <parameters>
13339     </parameters>
13340   </event>
13341 
13342   <event label="Monitor Contended Enter"
13343          id="MonitorContendedEnter" const="JVMTI_EVENT_MONITOR_CONTENDED_ENTER" filtered="thread" num="75">
13344     <description>
13345       Sent when a thread is attempting to enter a Java programming language
13346       monitor already acquired by another thread.
13347     </description>
13348     <origin>jvmpi</origin>
13349     <capabilities>
13350       <required id="can_generate_monitor_events"></required>
13351     </capabilities>
13352     <parameters>
13353       <param id="jni_env">
13354         <outptr>
13355           <struct>JNIEnv</struct>
13356         </outptr>
13357           <description>
13358             The JNI environment of the event (current) thread
13359           </description>
13360       </param>
13361       <param id="thread">
13362         <jthread/>
13363           <description>
13364             JNI local reference to the thread
13365             attempting to enter the monitor
13366           </description>
13367       </param>
13368       <param id="object">
13369         <jobject/>
13370           <description>
13371             JNI local reference to the monitor
13372           </description>
13373       </param>
13374     </parameters>
13375   </event>
13376 
13377   <event label="Monitor Contended Entered"
13378          id="MonitorContendedEntered" const="JVMTI_EVENT_MONITOR_CONTENDED_ENTERED" filtered="thread" num="76">
13379     <description>
13380       Sent when a thread enters a Java programming language
13381       monitor after waiting for it to be released by another thread.
13382     </description>
13383     <origin>jvmpi</origin>
13384     <capabilities>
13385       <required id="can_generate_monitor_events"></required>
13386     </capabilities>
13387     <parameters>
13388       <param id="jni_env">
13389         <outptr>
13390           <struct>JNIEnv</struct>
13391         </outptr>
13392           <description>
13393             The JNI environment of the event (current) thread
13394           </description>
13395       </param>
13396       <param id="thread">
13397         <jthread/>
13398           <description>
13399             JNI local reference to the thread entering
13400             the monitor
13401           </description>
13402       </param>
13403       <param id="object">
13404         <jobject/>
13405           <description>
13406             JNI local reference to the monitor
13407           </description>
13408       </param>
13409     </parameters>
13410   </event>
13411 
13412   <event label="Monitor Wait"
13413          id="MonitorWait" const="JVMTI_EVENT_MONITOR_WAIT" filtered="thread" num="73">
13414     <description>
13415       Sent when a thread is about to wait on an object.
13416     </description>
13417     <origin>jvmpi</origin>
13418     <capabilities>
13419       <required id="can_generate_monitor_events"></required>
13420     </capabilities>
13421     <parameters>
13422       <param id="jni_env">
13423         <outptr>
13424           <struct>JNIEnv</struct>
13425         </outptr>
13426           <description>
13427             The JNI environment of the event (current) thread
13428           </description>
13429       </param>
13430       <param id="thread">
13431         <jthread/>
13432           <description>
13433             JNI local reference to the thread about to wait
13434           </description>
13435       </param>
13436       <param id="object">
13437         <jobject/>
13438           <description>
13439             JNI local reference to the monitor
13440           </description>
13441       </param>
13442       <param id="timeout">
13443         <jlong/>
13444         <description>
13445           The number of milliseconds the thread will wait
13446         </description>
13447       </param>
13448     </parameters>
13449   </event>
13450 
13451   <event label="Monitor Waited"
13452          id="MonitorWaited" const="JVMTI_EVENT_MONITOR_WAITED" filtered="thread" num="74">
13453     <description>
13454       Sent when a thread finishes waiting on an object.
13455     </description>
13456     <origin>jvmpi</origin>
13457     <capabilities>
13458       <required id="can_generate_monitor_events"></required>
13459     </capabilities>
13460     <parameters>
13461       <param id="jni_env">
13462         <outptr>
13463           <struct>JNIEnv</struct>
13464         </outptr>
13465           <description>
13466             The JNI environment of the event (current) thread
13467           </description>
13468       </param>
13469       <param id="thread">
13470         <jthread/>
13471           <description>
13472             JNI local reference to the thread that was finished waiting
13473           </description>
13474       </param>
13475       <param id="object">
13476         <jobject/>
13477           <description>
13478             JNI local reference to the monitor.
13479           </description>
13480       </param>
13481       <param id="timed_out">
13482         <jboolean/>
13483         <description>
13484           True if the monitor timed out
13485         </description>
13486       </param>
13487     </parameters>
13488   </event>
13489 
13490   <event label="Resource Exhausted"
13491          id="ResourceExhausted" const="JVMTI_EVENT_RESOURCE_EXHAUSTED" num="80"
13492          since="1.1">
13493     <description>
13494       Sent when a VM resource needed by a running application has been exhausted.
13495       Except as required by the optional capabilities, the set of resources
13496       which report exhaustion is implementation dependent.
13497       <p/>
13498       The following bit flags define the properties of the resource exhaustion:
13499       <constants id="jvmtiResourceExhaustionFlags"
13500                  label="Resource Exhaustion Flags"
13501                  kind="bits"
13502                  since="1.1">
13503         <constant id="JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR" num="0x0001">
13504           After this event returns, the VM will throw a
13505           <code>java.lang.OutOfMemoryError</code>.
13506         </constant>
13507         <constant id="JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP" num="0x0002">
13508           The VM was unable to allocate memory from the <tm>Java</tm>
13509           platform <i>heap</i>.
13510           The <i>heap</i> is the runtime
13511           data area from which memory for all class instances and
13512           arrays are allocated.
13513         </constant>
13514         <constant id="JVMTI_RESOURCE_EXHAUSTED_THREADS" num="0x0004">
13515           The VM was unable to create a thread.
13516         </constant>
13517       </constants>
13518     </description>
13519     <origin>new</origin>
13520     <capabilities>
13521       <capability id="can_generate_resource_exhaustion_heap_events">
13522         Can generate events when the VM is unable to allocate memory from the
13523         <internallink id="JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP">heap</internallink>.
13524       </capability>
13525       <capability id="can_generate_resource_exhaustion_threads_events">
13526         Can generate events when the VM is unable to
13527         <internallink id="JVMTI_RESOURCE_EXHAUSTED_THREADS">create
13528         a thread</internallink>.
13529       </capability>
13530     </capabilities>
13531     <parameters>
13532       <param id="jni_env">
13533         <outptr>
13534           <struct>JNIEnv</struct>
13535         </outptr>
13536           <description>
13537             The JNI environment of the event (current) thread
13538           </description>
13539       </param>
13540       <param id="flags">
13541         <jint/>
13542         <description>
13543           Flags defining the properties of the of resource exhaustion
13544           as specified by the
13545           <internallink id="jvmtiResourceExhaustionFlags">Resource
13546           Exhaustion Flags</internallink>.
13547           </description>
13548         </param>
13549       <param id="reserved">
13550         <vmbuf><void/></vmbuf>
13551         <description>
13552           Reserved.
13553         </description>
13554       </param>
13555       <param id="description">
13556         <vmbuf><char/></vmbuf>
13557         <description>
13558           Description of the resource exhaustion, encoded as a
13559           <internallink id="mUTF">modified UTF-8</internallink> string.
13560         </description>
13561       </param>
13562     </parameters>
13563   </event>
13564 
13565   <event label="VM Object Allocation"
13566          id="VMObjectAlloc" const="JVMTI_EVENT_VM_OBJECT_ALLOC" num="84">
13567     <description>
13568       Sent when a method causes the virtual machine to directly allocate an
13569       Object visible to Java programming language code.
13570       Generally object allocation should be detected by instrumenting
13571       the bytecodes of allocating methods.
13572       Object allocation generated in native code by JNI function
13573       calls should be detected using
13574       <internallink id="jniIntercept">JNI function interception</internallink>.
13575       Some methods might not have associated bytecodes and are not
13576       native methods, they instead are executed directly by the
13577       VM. These methods should send this event.
13578       Virtual machines which are incapable of bytecode instrumentation
13579       for some or all of their methods can send this event.
13580 
13581       Note that the <internallink
13582       id="SampledObjectAlloc">SampledObjectAlloc</internallink>
13583       event is triggered on all Java object allocations, including those
13584       caused by bytecode method execution, JNI method execution, and
13585       directly by VM methods.
13586       <p/>
13587       Typical examples where this event might be sent:
13588       <ul>
13589         <li>Reflection -- for example, <code>java.lang.Class.newInstance()</code></li>
13590         <li>Methods not represented by bytecodes -- for example, VM intrinsics and
13591             J2ME preloaded classes</li>
13592       </ul>
13593       Cases where this event would not be generated:
13594       <ul>
13595         <li>Allocation due to bytecodes -- for example, the <code>new</code>
13596             and <code>newarray</code> VM instructions</li>
13597         <li>Allocation due to JNI function calls -- for example,
13598             <code>AllocObject</code></li>
13599         <li>Allocations during VM initialization</li>
13600         <li>VM internal objects</li>
13601       </ul>
13602     </description>
13603     <origin>new</origin>
13604     <capabilities>
13605       <required id="can_generate_vm_object_alloc_events"></required>
13606     </capabilities>
13607     <parameters>
13608       <param id="jni_env">
13609         <outptr>
13610           <struct>JNIEnv</struct>
13611         </outptr>
13612           <description>
13613             The JNI environment of the event (current) thread
13614           </description>
13615       </param>
13616       <param id="thread">
13617         <jthread/>
13618           <description>
13619             Thread allocating the object.
13620           </description>
13621       </param>
13622       <param id="object">
13623         <jobject/>
13624           <description>
13625             JNI local reference to the object that was allocated.
13626           </description>
13627       </param>
13628       <param id="object_klass">
13629         <jclass/>
13630           <description>
13631             JNI local reference to the class of the object.
13632           </description>
13633       </param>
13634       <param id="size">
13635         <jlong/>
13636         <description>
13637             Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
13638         </description>
13639       </param>
13640     </parameters>
13641   </event>
13642 
13643   <event label="Sampled Object Allocation"
13644     id="SampledObjectAlloc" const="JVMTI_EVENT_SAMPLED_OBJECT_ALLOC" filtered="thread" num="86" since="11">
13645     <description>
13646       Sent when an allocated object is sampled.
13647       By default, the sampling interval is set to 512KB. The sampling is semi-random to avoid
13648       pattern-based bias and provides an approximate overall average interval over long periods of
13649       sampling.
13650       <p/>
13651       Each thread tracks how many bytes it has allocated since it sent the last event.
13652       When the number of bytes exceeds the sampling interval, it will send another event.
13653       This implies that, on average, one object will be sampled every time a thread has
13654       allocated 512KB bytes since the last sample.
13655       <p/>
13656       Note that the sampler is pseudo-random: it will not sample every 512KB precisely.
13657       The goal of this is to ensure high quality sampling even if allocation is
13658       happening in a fixed pattern (i.e., the same set of objects are being allocated
13659       every 512KB).
13660       <p/>
13661       If another sampling interval is required, the user can call
13662       <functionlink id="SetHeapSamplingInterval"></functionlink> with a strictly positive integer value,
13663       representing the new sampling interval.
13664       <p/>
13665       This event is sent once the sampled allocation has been performed.  It provides the object, stack trace
13666       of the allocation, the thread allocating, the size of allocation, and the object's class.
13667       <p/>
13668       A typical use case of this system is to determine where heap allocations originate.
13669       In conjunction with weak references and the function
13670       <functionlink id="GetStackTrace"></functionlink>, a user can track which objects were allocated from which
13671       stack trace, and which are still live during the execution of the program.
13672     </description>
13673     <origin>new</origin>
13674     <capabilities>
13675       <required id="can_generate_sampled_object_alloc_events"></required>
13676     </capabilities>
13677     <parameters>
13678       <param id="jni_env">
13679         <outptr>
13680           <struct>JNIEnv</struct>
13681         </outptr>
13682         <description>
13683           The JNI environment of the event (current) thread.
13684         </description>
13685       </param>
13686       <param id="thread">
13687         <jthread/>
13688         <description>
13689           Thread allocating the object.
13690         </description>
13691       </param>
13692       <param id="object">
13693         <jobject/>
13694         <description>
13695           JNI local reference to the object that was allocated.
13696         </description>
13697       </param>
13698       <param id="object_klass">
13699         <jclass/>
13700         <description>
13701           JNI local reference to the class of the object
13702         </description>
13703       </param>
13704       <param id="size">
13705         <jlong/>
13706         <description>
13707           Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
13708         </description>
13709       </param>
13710     </parameters>
13711   </event>
13712 
13713   <event label="Object Free"
13714         id="ObjectFree" const="JVMTI_EVENT_OBJECT_FREE" num="83">
13715     <description>
13716       An Object Free event is sent when the garbage collector frees an object.
13717       Events are only sent for tagged objects--see
13718       <internallink id="Heap">heap functions</internallink>.
13719       <p/>
13720       The event handler must not use JNI functions and
13721       must not use <jvmti/> functions except those which
13722       specifically allow such use (see the raw monitor, memory management,
13723       and environment local storage functions).
13724     </description>
13725     <origin>new</origin>
13726     <capabilities>
13727       <required id="can_generate_object_free_events"></required>
13728     </capabilities>
13729     <parameters>
13730       <param id="tag">
13731         <jlong/>
13732         <description>
13733           The freed object's tag
13734         </description>
13735       </param>
13736     </parameters>
13737   </event>
13738 
13739   <event label="Garbage Collection Start"
13740          id="GarbageCollectionStart" const="JVMTI_EVENT_GARBAGE_COLLECTION_START" num="81">
13741     <description>
13742       A Garbage Collection Start event is sent when a
13743       garbage collection pause begins.
13744       Only stop-the-world collections are reported--that is, collections during
13745       which all threads cease to modify the state of the Java virtual machine.
13746       This means that some collectors will never generate these events.
13747       This event is sent while the VM is still stopped, thus
13748       the event handler must not use JNI functions and
13749       must not use <jvmti/> functions except those which
13750       specifically allow such use (see the raw monitor, memory management,
13751       and environment local storage functions).
13752       <p/>
13753       This event is always sent as a matched pair with
13754       <eventlink id="GarbageCollectionFinish"/>
13755       (assuming both events are enabled) and no garbage collection
13756       events will occur between them.
13757     </description>
13758     <origin>new</origin>
13759     <capabilities>
13760       <required id="can_generate_garbage_collection_events"></required>
13761     </capabilities>
13762     <parameters>
13763     </parameters>
13764   </event>
13765 
13766   <event label="Garbage Collection Finish"
13767          id="GarbageCollectionFinish" const="JVMTI_EVENT_GARBAGE_COLLECTION_FINISH" num="82">
13768     <description>
13769       A Garbage Collection Finish event is sent when a
13770       garbage collection pause ends.
13771       This event is sent while the VM is still stopped, thus
13772       the event handler must not use JNI functions and
13773       must not use <jvmti/> functions except those which
13774       specifically allow such use (see the raw monitor, memory management,
13775       and environment local storage functions).
13776       <p/>
13777       Some agents may need to do post garbage collection operations that
13778       require the use of the disallowed <jvmti/> or JNI functions. For these
13779       cases an agent thread can be created which waits on a raw monitor,
13780       and the handler for the Garbage Collection Finish event simply
13781       notifies the raw monitor
13782       <p/>
13783       This event is always sent as a matched pair with
13784       <eventlink id="GarbageCollectionStart"/> (assuming both events are enabled).
13785       <issue>
13786         The most important use of this event is to provide timing information,
13787         and thus additional information is not required.  However,
13788         information about the collection which is "free" should be included -
13789         what that information is needs to be determined.
13790       </issue>
13791     </description>
13792     <origin>new</origin>
13793     <capabilities>
13794       <required id="can_generate_garbage_collection_events"></required>
13795     </capabilities>
13796     <parameters>
13797     </parameters>
13798   </event>
13799 
13800   <elide>
13801   <event label="Verbose Output" phase="any"
13802          id="VerboseOutput" const="JVMTI_EVENT_VERBOSE_OUTPUT" num="85">
13803     <description>
13804       Send verbose messages as strings.
13805         <issue>
13806           This format is extremely fragile, as it can change with each
13807           platform, collector and version.  Alternatives include:
13808           <ul>
13809             <li>building off Java programming language M and M APIs</li>
13810             <li>XML</li>
13811             <li>key/value pairs</li>
13812             <li>removing it</li>
13813           </ul>
13814         </issue>
13815         <issue>
13816           Though this seemed trivial to implement.
13817           In the RI it appears this will be quite complex.
13818         </issue>
13819     </description>
13820     <origin>new</origin>
13821     <capabilities>
13822     </capabilities>
13823     <parameters>
13824       <param id="flag">
13825         <enum>jvmtiVerboseFlag</enum>
13826         <description>
13827           Which verbose output is being sent.
13828         </description>
13829       </param>
13830       <param id="message">
13831         <vmbuf><char/></vmbuf>
13832         <description>
13833           Message text, encoded as a
13834           <internallink id="mUTF">modified UTF-8</internallink> string.
13835         </description>
13836       </param>
13837     </parameters>
13838   </event>
13839   </elide>
13840 
13841 </eventsection>
13842 
13843 <datasection>
13844   <intro>
13845     <jvmti/> extends the data types defined by JNI.
13846   </intro>
13847   <basetypes id="jniTypes" label="JNI Types Used in the JVM Tool Interface">
13848     <basetype id="jboolean">
13849       <description>
13850         Holds a Java programming language <code>boolean</code>.
13851         Unsigned 8 bits.
13852       </description>
13853     </basetype>
13854     <basetype id="jchar">
13855       <description>
13856         Holds a Java programming language <code>char</code>.
13857         Unsigned 16 bits.
13858       </description>
13859     </basetype>
13860     <basetype id="jint">
13861       <description>
13862         Holds a Java programming language <code>int</code>.
13863         Signed 32 bits.
13864       </description>
13865     </basetype>
13866     <basetype id="jlong">
13867       <description>
13868         Holds a Java programming language <code>long</code>.
13869         Signed 64 bits.
13870       </description>
13871     </basetype>
13872     <basetype id="jfloat">
13873       <description>
13874         Holds a Java programming language <code>float</code>.
13875         32 bits.
13876       </description>
13877     </basetype>
13878     <basetype id="jdouble">
13879       <description>
13880         Holds a Java programming language <code>double</code>.
13881         64 bits.
13882       </description>
13883     </basetype>
13884     <basetype id="jobject">
13885       <description>
13886         Holds a Java programming language object.
13887       </description>
13888     </basetype>
13889     <basetype id="jclass">
13890       <description>
13891         Holds a Java programming language class.
13892       </description>
13893     </basetype>
13894     <basetype id="jvalue">
13895       <description>
13896         Is a union of all primitive types and <code>jobject</code>.  Thus, holds any Java
13897         programming language value.
13898       </description>
13899     </basetype>
13900     <basetype id="jfieldID">
13901       <description>
13902         Identifies a Java programming language field.
13903         <code>jfieldID</code>s returned by <jvmti/> functions and events may be
13904         safely stored.
13905       </description>
13906     </basetype>
13907     <basetype id="jmethodID">
13908       <description>
13909         Identifies a Java programming language method, initializer, or constructor.
13910         <code>jmethodID</code>s returned by <jvmti/> functions and events may be
13911         safely stored.  However, if the class is unloaded, they become invalid
13912         and must not be used.
13913       </description>
13914     </basetype>
13915     <basetype id="JNIEnv">
13916       <description>
13917         Pointer to the JNI function table.  Pointer to this (<code>JNIEnv *</code>)
13918         is a JNI environment.
13919       </description>
13920     </basetype>
13921   </basetypes>
13922 
13923   <basetypes id="jvmtiTypes" label="JVM Tool Interface Base Types">
13924     <basetype id="jvmtiEnv">
13925       <description>
13926         The <jvmti/> <internallink id="environments">environment</internallink> pointer.
13927         See the <internallink id="FunctionSection">Function Section</internallink>.
13928         <code>jvmtiEnv</code> points to the
13929         <internallink id="FunctionTable">function table</internallink> pointer.
13930       </description>
13931     </basetype>
13932     <basetype id="jthread">
13933       <definition>typedef jobject jthread;</definition>
13934       <description>
13935         Subtype of <datalink id="jobject"></datalink> that holds a thread.
13936       </description>
13937     </basetype>
13938     <basetype id="jthreadGroup">
13939       <definition>typedef jobject jthreadGroup;</definition>
13940       <description>
13941         Subtype of <datalink id="jobject"></datalink> that holds a thread group.
13942       </description>
13943     </basetype>
13944     <basetype id="jlocation">
13945       <definition>typedef jlong jlocation;</definition>
13946       <description>
13947         A 64 bit value, representing a monotonically increasing
13948         executable position within a method.
13949         <code>-1</code> indicates a native method.
13950         See <functionlink id="GetJLocationFormat"></functionlink> for the format on a
13951         given VM.
13952       </description>
13953     </basetype>
13954     <basetype id="jrawMonitorID">
13955       <definition>struct _jrawMonitorID;
13956 typedef struct _jrawMonitorID *jrawMonitorID;</definition>
13957       <description>
13958         A raw monitor.
13959       </description>
13960     </basetype>
13961     <basetype id="jvmtiError">
13962       <description>
13963         Holds an error return code.
13964         See the <internallink id="ErrorSection">Error section</internallink> for possible values.
13965         <example>
13966 typedef enum {
13967     JVMTI_ERROR_NONE = 0,
13968     JVMTI_ERROR_INVALID_THREAD = 10,
13969       ...
13970 } jvmtiError;
13971 </example>
13972       </description>
13973     </basetype>
13974     <basetype id="jvmtiEvent">
13975       <description>
13976         An identifier for an event type.
13977         See the <internallink id="EventSection">Event section</internallink> for possible values.
13978         It is guaranteed that future versions of this specification will
13979         never assign zero as an event type identifier.
13980 <example>
13981 typedef enum {
13982     JVMTI_EVENT_SINGLE_STEP = 1,
13983     JVMTI_EVENT_BREAKPOINT = 2,
13984       ...
13985 } jvmtiEvent;
13986 </example>
13987       </description>
13988     </basetype>
13989     <basetype id="jvmtiEventCallbacks" name="eventCallbacks">
13990       <description>
13991         The callbacks used for events.
13992 <example>
13993 typedef struct {
13994     jvmtiEventVMInit VMInit;
13995     jvmtiEventVMDeath VMDeath;
13996       ...
13997 } jvmtiEventCallbacks;
13998 </example>
13999         See <internallink id="jvmtiEventCallbacks">event callbacks</internallink>
14000         for the complete structure.
14001         <p/>
14002         Where, for example, the VM initialization callback is defined:
14003 <example>
14004 typedef void (JNICALL *jvmtiEventVMInit)
14005     (jvmtiEnv *jvmti_env,
14006      JNIEnv* jni_env,
14007      jthread thread);
14008 </example>
14009         See the individual events for the callback function definition.
14010       </description>
14011     </basetype>
14012     <basetype id="jniNativeInterface">
14013       <definition>typedef struct JNINativeInterface_ jniNativeInterface;</definition>
14014       <description>
14015         Typedef for the JNI function table <code>JNINativeInterface</code>
14016         defined in the
14017         <externallink id="jni/functions.html#interface-function-table">
14018           JNI Specification</externallink>.
14019         The JNI reference implementation defines this with an underscore.
14020       </description>
14021     </basetype>
14022   </basetypes>
14023 
14024 </datasection>
14025 
14026 <issuessection label="Issues">
14027   <intro id="suspendRequired" label="Resolved Issue: Suspend - Required or Automatic">
14028     JVMDI requires that the agent suspend threads before calling
14029     certain sensitive functions.  JVMPI requires garbage collection to be
14030     disabled before calling certain sensitive functions.
14031     It was suggested that rather than have this requirement, that
14032     VM place itself in a suitable state before performing an
14033     operation.  This makes considerable sense since each VM
14034     knows its requirements and can most easily arrange a
14035     safe state.
14036     <p/>
14037     The ability to externally suspend/resume threads will, of
14038     course, remain.  The ability to enable/disable garbage collection will not.
14039     <p/>
14040     This issue is resolved--suspend will not
14041     be required.  The spec has been updated to reflect this.
14042   </intro>
14043 
14044   <intro id="stackSampling" label="Resolved Issue: Call Stack Sampling">
14045     There are a variety of approaches to sampling call stacks.
14046     The biggest bifurcation is between VM controlled and agent
14047     controlled.
14048     <p/>
14049     This issue is resolved--agent controlled
14050     sampling will be the approach.
14051   </intro>
14052 
14053   <intro id="threadRepresentation" label="Resolved Issue: Thread Representation">
14054     JVMDI represents threads as jthread.  JVMPI primarily
14055     uses JNIEnv* to represent threads.
14056     <p/>
14057     The Expert Group has chosen jthread as the representation
14058     for threads in <jvmti/>.
14059     JNIEnv* is sent by
14060     events since it is needed to JNI functions.  JNIEnv, per the
14061     JNI spec, are not supposed to be used outside their thread.
14062   </intro>
14063 
14064   <intro id="design" label="Resolved Issue: Method Representation">
14065     The JNI spec allows an implementation to depend on jclass/jmethodID
14066     pairs, rather than simply a jmethodID, to reference a method.
14067     JVMDI, for consistency, choose the same representation.
14068     JVMPI, however, specifies that a jmethodID alone maps to a
14069     method.  Both of the Sun <tm>J2SE</tm> virtual machines (Classic and <tm>HotSpot</tm>) store
14070     pointers in jmethodIDs, and as a result, a jmethodID is sufficient.
14071     In fact, any JVM implementation that supports JVMPI must have
14072     such a representation.
14073     <jvmti/> will use jmethodID as a unique representation of a method
14074     (no jclass is used).
14075     There should be efficiency gains, particularly in
14076     functionality like stack dumping, to this representation.
14077     <p/>
14078     Note that fields were not used in JVMPI and that the access profile
14079     of fields differs from methods--for implementation efficiency
14080     reasons, a jclass/jfieldID pair will still be needed for field
14081     reference.
14082   </intro>
14083 
14084   <intro id="localReferenceIssue" label="Resolved Issue: Local References">
14085     Functions return local references.
14086   </intro>
14087 
14088   <intro id="frameRep" label="Resolved Issue: Representation of frames">
14089     In JVMDI, a frame ID is used to represent a frame.  Problem with this
14090     is that a VM must track when a frame becomes invalid, a far better
14091     approach, and the one used in <jvmti/>, is to reference frames by depth.
14092   </intro>
14093 
14094   <intro id="requiredCapabilities" label="Issue: Required Capabilities">
14095     Currently, having a required capabilities means that the functionality
14096     is optional.   Capabilities are useful even for required functionality
14097     since they can inform the VM is needed set-up.  Thus, there should be
14098     a set of capabilities that a conformant implementation must provide
14099     (if requested during Agent_OnLoad).
14100   </intro>
14101 
14102   <intro id="taghint" label="Proposal: add tag hint function">
14103     A hint of the percentage of objects that will be tagged would
14104     help the VM pick a good implementation.
14105   </intro>
14106 
14107   <intro id="moreMonitorQueries" label="Request: More Monitor Quires">
14108   How difficult or easy would be to extend the monitor_info category to include
14109     <pre>
14110   - current number of monitors
14111   - enumeration of monitors
14112   - enumeration of threads waiting on a given monitor
14113     </pre>
14114   The reason for my question is the fact that current get_monitor_info support
14115   requires the agent to specify a given thread to get the info which is probably
14116   OK in the profiling/debugging space, while in the monitoring space the agent
14117   could be watching the monitor list and then decide which thread to ask for
14118   the info. You might ask why is this important for monitoring .... I think it
14119   can aid in the detection/prediction of application contention caused by hot-locks.
14120   </intro>
14121 </issuessection>
14122 
14123 <changehistory id="ChangeHistory" update="09/05/07">
14124   <intro>
14125     The <jvmti/> specification is an evolving document with major, minor,
14126     and micro version numbers.
14127     A released version of the specification is uniquely identified
14128     by its major and minor version.
14129     The functions, events, and capabilities in this specification
14130     indicate a "Since" value which is the major and minor version in
14131     which it was introduced.
14132     The version of the specification implemented by the VM can
14133     be retrieved at runtime with the <functionlink id="GetVersionNumber"/>
14134     function.
14135   </intro>
14136   <change date="14 Nov 2002">
14137     Converted to XML document.
14138   </change>
14139   <change date="14 Nov 2002">
14140     Elided heap dump functions (for now) since what was there
14141     was wrong.
14142   </change>
14143   <change date="18 Nov 2002">
14144     Added detail throughout.
14145   </change>
14146   <change date="18 Nov 2002">
14147     Changed JVMTI_THREAD_STATUS_RUNNING to JVMTI_THREAD_STATUS_RUNNABLE.
14148   </change>
14149   <change date="19 Nov 2002">
14150     Added AsyncGetStackTrace.
14151   </change>
14152   <change date="19 Nov 2002">
14153     Added jframeID return to GetStackTrace.
14154   </change>
14155   <change date="19 Nov 2002">
14156     Elided GetCurrentFrame and GetCallingFrame functions (for now) since what was there
14157     since they are redundant with GetStackTrace.
14158   </change>
14159   <change date="19 Nov 2002">
14160     Elided ClearAllBreakpoints since it has always been redundant.
14161   </change>
14162   <change date="19 Nov 2002">
14163     Added GetSystemProperties.
14164   </change>
14165   <change date="19 Nov 2002">
14166     Changed the thread local storage functions to use jthread.
14167   </change>
14168   <change date="20 Nov 2002">
14169     Added GetJLocationFormat.
14170   </change>
14171   <change date="22 Nov 2002">
14172     Added events and introductory text.
14173   </change>
14174   <change date="22 Nov 2002">
14175     Cross reference type and constant definitions.
14176   </change>
14177   <change date="24 Nov 2002">
14178     Added DTD.
14179   </change>
14180   <change date="24 Nov 2002">
14181     Added capabilities function section.
14182   </change>
14183   <change date="29 Nov 2002">
14184     Assign capabilities to each function and event.
14185   </change>
14186   <change date="29 Nov 2002">
14187     Add <internallink id="jniIntercept">JNI interception functions</internallink>.
14188   </change>
14189   <change date="30 Nov 2002">
14190     Auto generate SetEventNotificationMode capabilities.
14191   </change>
14192   <change date="30 Nov 2002">
14193     Add <eventlink id="VMObjectAlloc"></eventlink> event.
14194   </change>
14195   <change date="30 Nov 2002">
14196     Add <eventlink id="DynamicCodeGenerated"></eventlink> event.
14197   </change>
14198   <change date="30 Nov 2002">
14199     Add const to declarations.
14200   </change>
14201   <change date="30 Nov 2002">
14202     Change method exit and frame pop to send on exception.
14203   </change>
14204   <change date="1 Dec 2002">
14205     Add ForceGarbageCollection.
14206   </change>
14207   <change date="2 Dec 2002">
14208     Redo Xrun section; clarify GetStackTrace and add example;
14209     Fix width problems; use "agent" consistently.
14210   </change>
14211   <change date="8 Dec 2002">
14212     Remove previous start-up intro.
14213     Add <internallink id="environments"><jvmti/> Environments</internallink>
14214     section.
14215   </change>
14216   <change date="8 Dec 2002">
14217     Add <functionlink id="DisposeEnvironment"></functionlink>.
14218   </change>
14219   <change date="9 Dec 2002">
14220     Numerous minor updates.
14221   </change>
14222   <change date="15 Dec 2002">
14223     Add heap profiling functions added:
14224     get/set annotation, iterate live objects/heap.
14225     Add heap profiling functions place holder added:
14226     heap roots.
14227     Heap profiling event added: object free.
14228     Heap profiling event redesigned: vm object allocation.
14229     Heap profiling event placeholders added: garbage collection start/finish.
14230     Native method bind event added.
14231   </change>
14232   <change date="19 Dec 2002">
14233     Revamp suspend/resume functions.
14234     Add origin information with jvmdi tag.
14235     Misc fixes.
14236   </change>
14237   <change date="24 Dec 2002">
14238     Add semantics to types.
14239   </change>
14240   <change date="27 Dec 2002">
14241     Add local reference section.
14242     Autogenerate parameter descriptions from types.
14243   </change>
14244   <change date="28 Dec 2002">
14245     Document that RunAgentThread sends threadStart.
14246   </change>
14247   <change date="29 Dec 2002">
14248     Remove redundant local ref and dealloc warning.
14249     Convert GetRawMonitorName to allocated buffer.
14250     Add GenerateEvents.
14251   </change>
14252   <change date="30 Dec 2002">
14253     Make raw monitors a type and rename to "jrawMonitorID".
14254   </change>
14255   <change date="1 Jan 2003">
14256     Include origin information.
14257     Clean-up JVMDI issue references.
14258     Remove Deallocate warnings which are now automatically generated.
14259   </change>
14260   <change date="2 Jan 2003">
14261     Fix representation issues for jthread.
14262   </change>
14263   <change date="3 Jan 2003">
14264     Make capabilities buffered out to 64 bits - and do it automatically.
14265   </change>
14266   <change date="4 Jan 2003">
14267     Make constants which are enumeration into enum types.
14268     Parameters now of enum type.
14269     Clean-up and index type section.
14270     Replace remaining datadef entities with callback.
14271   </change>
14272   <change date="7 Jan 2003">
14273     Correct GenerateEvents description.
14274     More internal semantics work.
14275   </change>
14276   <change date="9 Jan 2003">
14277     Replace previous GetSystemProperties with two functions
14278     which use allocated information instead fixed.
14279     Add SetSystemProperty.
14280     More internal semantics work.
14281   </change>
14282   <change date="12 Jan 2003">
14283     Add varargs to end of SetEventNotificationMode.
14284   </change>
14285   <change date="20 Jan 2003">
14286     Finish fixing spec to reflect that alloc sizes are jlong.
14287   </change>
14288   <change date="22 Jan 2003">
14289     Allow NULL as RunAgentThread arg.
14290   </change>
14291   <change date="22 Jan 2003">
14292     Fixed names to standardized naming convention
14293     Removed AsyncGetStackTrace.
14294   </change>
14295   <change date="29 Jan 2003">
14296     Since we are using jthread, removed GetThread.
14297   </change>
14298   <change date="31 Jan 2003">
14299     Change GetFieldName to allow NULLs like GetMethodName.
14300   </change>
14301   <change date="29 Feb 2003" version="v40">
14302       Rewrite the introductory text, adding sections on
14303       start-up, environments and bytecode instrumentation.
14304       Change the command line arguments per EG discussions.
14305       Add an introduction to the capabilities section.
14306       Add the extension mechanism category and functions.
14307       Mark for deletion, but clarified anyhow, SuspendAllThreads.
14308       Rename IterateOverLiveObjects to IterateOverReachableObjects and
14309       change the text accordingly.
14310       Clarify IterateOverHeap.
14311       Clarify CompiledMethodLoad.
14312       Discuss prerequisite state for Calling Functions.
14313       Clarify SetAllocationHooks.
14314       Added issues ("To be resolved:") through-out.
14315       And so on...
14316   </change>
14317   <change date="6 Mar 2003" version="v41">
14318       Remove struct from the call to GetOwnedMonitorInfo.
14319       Automatically generate most error documentation, remove
14320       (rather broken) hand written error doc.
14321       Better describe capability use (empty initial set).
14322       Add min value to jint params.
14323       Remove the capability can_access_thread_local_storage.
14324       Rename error JVMTI_ERROR_NOT_IMPLEMENTED to JVMTI_ERROR_MUST_POSSESS_CAPABILITY;
14325       same for *NOT_IMPLEMENTED.
14326       Description fixes.
14327   </change>
14328   <change date="8 Mar 2003" version="v42">
14329       Rename GetClassSignature to GetClassName.
14330       Rename IterateOverClassObjects to IterateOverInstancesOfClass.
14331       Remove GetMaxStack (operand stack isn't used in <jvmti/>).
14332       Description fixes: define launch-time, remove native frame pop
14333       from PopFrame, and assorted clarifications.
14334   </change>
14335   <change date="8 Mar 2003" version="v43">
14336       Fix minor editing problem.
14337   </change>
14338   <change date="10 Mar 2003" version="v44">
14339       Add phase information.
14340       Remap (compact) event numbers.
14341   </change>
14342   <change date="11 Mar 2003" version="v45">
14343       More phase information - allow "any".
14344       Elide raw monitor queries and events.
14345       Minor description fixes.
14346   </change>
14347   <change date="12 Mar 2003" version="v46">
14348       Add GetPhase.
14349       Use "phase" through document.
14350       Elide GetRawMonitorName.
14351       Elide GetObjectMonitors.
14352   </change>
14353   <change date="12 Mar 2003" version="v47">
14354       Fixes from link, XML, and spell checking.
14355       Auto-generate the callback structure.
14356   </change>
14357   <change date="13 Mar 2003" version="v48">
14358       One character XML fix.
14359   </change>
14360   <change date="13 Mar 2003" version="v49">
14361       Change function parameter names to be consistent with
14362       event parameters (fooBarBaz becomes foo_bar_baz).
14363   </change>
14364   <change date="14 Mar 2003" version="v50">
14365       Fix broken link.  Fix thread markers.
14366   </change>
14367   <change date="14 Mar 2003" version="v51">
14368       Change constants so they are under 128 to workaround
14369       compiler problems.
14370   </change>
14371   <change date="23 Mar 2003" version="v52">
14372       Overhaul capabilities.  Separate GetStackTrace into
14373       GetStackTrace and GetStackFrames.
14374   </change>
14375   <change date="8 Apr 2003" version="v54">
14376       Use depth instead of jframeID to reference frames.
14377       Remove the now irrelevant GetCurrentFrame, GetCallerFrame and GetStackFrames.
14378       Remove frame arg from events.
14379   </change>
14380   <change date="9 Apr 2003" version="v55">
14381       Remove GetObjectWithAnnotation since tests show bufferred approach more efficient.
14382       Add missing annotation_count to GetObjectsWithAnnotations
14383   </change>
14384   <change date="10 Apr 2003" version="v56">
14385       Remove confusing parenthetical statement in GetObjectsWithAnnotations
14386   </change>
14387   <change date="13 Apr 2003" version="v58">
14388       Replace jclass/jmethodID representation of method with simply jmethodID;
14389       Pass JvmtiEnv* as first arg of every event; remove JNIEnv* where inappropriate.
14390       Replace can_access_frames with can_access_local_variables; remove from purely stack access.
14391       Use can_get_synthetic_attribute; fix description.
14392       Clarify that zero length arrays must be deallocated.
14393       Clarify RelinquishCapabilities.
14394       Generalize JVMTI_ERROR_VM_DEAD to JVMTI_ERROR_WRONG_PHASE.
14395   </change>
14396   <change date="27 Apr 2003" version="v59">
14397       Remove lingering indirect references to OBSOLETE_METHOD_ID.
14398   </change>
14399   <change date="4 May 2003" version="v60">
14400       Allow DestroyRawMonitor during OnLoad.
14401   </change>
14402   <change date="7 May 2003" version="v61">
14403       Added not monitor owner error return to DestroyRawMonitor.
14404   </change>
14405   <change date="13 May 2003" version="v62">
14406       Clarify semantics of raw monitors.
14407       Change flags on <code>GetThreadStatus</code>.
14408       <code>GetClassLoader</code> return NULL for the bootstrap class loader.
14409       Add <code>GetClassName</code> issue.
14410       Define local variable signature.
14411       Disallow zero in annotations array of <code>GetObjectsWithAnnotations</code>.
14412       Remove over specification in <code>GetObjectsWithAnnotations</code>.
14413       Elide <code>SetAllocationHooks</code>.
14414       Elide <code>SuspendAllThreads</code>.
14415   </change>
14416   <change date="14 May 2003" version="v63">
14417       Define the data type <code>jvmtiEventCallbacks</code>.
14418       Zero length allocations return NULL.
14419       Keep SetAllocationHooks in JVMDI, but remove from <jvmti/>.
14420       Add JVMTI_THREAD_STATUS_FLAG_INTERRUPTED.
14421   </change>
14422   <change date="15 May 2003" version="v64">
14423       Better wording, per review.
14424   </change>
14425   <change date="15 May 2003" version="v65">
14426       First Alpha.
14427       Make jmethodID and jfieldID unique, jclass not used.
14428   </change>
14429   <change date="27 May 2003" version="v66">
14430       Fix minor XSLT errors.
14431   </change>
14432   <change date="13 June 2003" version="v67">
14433       Undo making jfieldID unique (jmethodID still is).
14434   </change>
14435   <change date="17 June 2003" version="v68">
14436       Changes per June 11th Expert Group meeting --
14437       Overhaul Heap functionality: single callback,
14438       remove GetHeapRoots, add reachable iterators,
14439       and rename "annotation" to "tag".
14440       NULL thread parameter on most functions is current
14441       thread.
14442       Add timers.
14443       Remove ForceExit.
14444       Add GetEnvironmentLocalStorage.
14445       Add verbose flag and event.
14446       Add AddToBootstrapClassLoaderSearch.
14447       Update ClassFileLoadHook.
14448   </change>
14449   <change date="18 June 2003" version="v69">
14450       Clean up issues sections.
14451       Rename GetClassName back to GetClassSignature and
14452       fix description.
14453       Add generic signature to GetClassSignature,
14454       GetFieldSignature, GetMethodSignature, and
14455       GetLocalVariableTable.
14456       Elide EstimateCostOfCapabilities.
14457       Clarify that the system property functions operate
14458       on the VM view of system properties.
14459       Clarify Agent_OnLoad.
14460       Remove "const" from JNIEnv* in events.
14461       Add metadata accessors.
14462   </change>
14463   <change date="18 June 2003" version="v70">
14464       Add start_depth to GetStackTrace.
14465       Move system properties to a new category.
14466       Add GetObjectSize.
14467       Remove "X" from command line flags.
14468       XML, HTML, and spell check corrections.
14469   </change>
14470   <change date="19 June 2003" version="v71">
14471       Fix JVMTI_HEAP_ROOT_THREAD to be 6.
14472       Make each synopsis match the function name.
14473       Fix unclear wording.
14474   </change>
14475   <change date="26 June 2003" version="v72">
14476       SetThreadLocalStorage and SetEnvironmentLocalStorage should allow value
14477       to be set to NULL.
14478       NotifyFramePop, GetFrameLocationm and all the local variable operations
14479       needed to have their wording about frames fixed.
14480       Grammar and clarity need to be fixed throughout.
14481       Capitalization and puntuation need to be consistent.
14482       Need micro version number and masks for accessing major, minor, and micro.
14483       The error code lists should indicate which must be returned by
14484       an implementation.
14485       The command line properties should be visible in the properties functions.
14486       Disallow popping from the current thread.
14487       Allow implementations to return opaque frame error when they cannot pop.
14488       The NativeMethodBind event should be sent during any phase.
14489       The DynamicCodeGenerated event should be sent during any phase.
14490       The following functions should be allowed to operate before VMInit:
14491         Set/GetEnvironmentLocalStorage
14492         GetMethodDeclaringClass
14493         GetClassSignature
14494         GetClassModifiers
14495         IsInterface
14496         IsArrayClass
14497         GetMethodName
14498         GetMethodModifiers
14499         GetMaxLocals
14500         GetArgumentsSize
14501         GetLineNumberTable
14502         GetMethodLocation
14503         IsMethodNative
14504         IsMethodSynthetic.
14505       Other changes (to XSL):
14506       Argument description should show asterisk after not before pointers.
14507       NotifyFramePop, GetFrameLocationm and all the local variable operations
14508       should hsve the NO_MORE_FRAMES error added.
14509       Not alive threads should have a different error return than invalid thread.
14510   </change>
14511   <change date="7 July 2003" version="v73">
14512       VerboseOutput event was missing message parameter.
14513       Minor fix-ups.
14514   </change>
14515   <change date="14 July 2003" version="v74">
14516       Technical Publications Department corrections.
14517       Allow thread and environment local storage to be set to NULL.
14518   </change>
14519   <change date="23 July 2003" version="v75">
14520       Use new Agent_OnLoad rather than overloaded JVM_OnLoad.
14521       Add JNICALL to callbacks (XSL).
14522       Document JNICALL requirement for both events and callbacks (XSL).
14523       Restrict RedefineClasses to methods and attributes.
14524       Elide the VerboseOutput event.
14525       VMObjectAlloc: restrict when event is sent and remove method parameter.
14526       Finish loose ends from Tech Pubs edit.
14527   </change>
14528   <change date="24 July 2003" version="v76">
14529       Change ClassFileLoadHook event to send the class instead of a boolean of redefine.
14530   </change>
14531   <change date="24 July 2003" version="v77">
14532       XML fixes.
14533       Minor text clarifications and corrections.
14534   </change>
14535   <change date="24 July 2003" version="v78">
14536       Remove GetExceptionHandlerTable and GetThrownExceptions from <jvmti/>.
14537       Clarify that stack frames are JVM Spec frames.
14538       Split can_get_source_info into can_get_source_file_name, can_get_line_numbers,
14539       and can_get_source_debug_extension.
14540       PopFrame cannot have a native calling method.
14541       Removed incorrect statement in GetClassloaderClasses
14542       (see <vmspec chapter="4.4"/>).
14543   </change>
14544   <change date="24 July 2003" version="v79">
14545       XML and text fixes.
14546       Move stack frame description into Stack Frame category.
14547   </change>
14548   <change date="26 July 2003" version="v80">
14549       Allow NULL (means bootstrap loader) for GetClassloaderClasses.
14550       Add new heap reference kinds for references from classes.
14551       Add timer information struct and query functions.
14552       Add AvailableProcessors.
14553       Rename GetOtherThreadCpuTime to GetThreadCpuTime.
14554       Explicitly add JVMTI_ERROR_INVALID_THREAD and JVMTI_ERROR_THREAD_NOT_ALIVE
14555       to SetEventNotification mode.
14556       Add initial thread to the VM_INIT event.
14557       Remove platform assumptions from AddToBootstrapClassLoaderSearch.
14558   </change>
14559   <change date="26 July 2003" version="v81">
14560       Grammar and clarity changes per review.
14561   </change>
14562   <change date="27 July 2003" version="v82">
14563       More grammar and clarity changes per review.
14564       Add Agent_OnUnload.
14565   </change>
14566   <change date="28 July 2003" version="v83">
14567       Change return type of Agent_OnUnload to void.
14568   </change>
14569   <change date="28 July 2003" version="v84">
14570       Rename JVMTI_REFERENCE_ARRAY to JVMTI_REFERENCE_ARRAY_ELEMENT.
14571   </change>
14572   <change date="28 July 2003" version="v85">
14573       Steal java.lang.Runtime.availableProcessors() wording for
14574       AvailableProcessors().
14575       Guarantee that zero will never be an event ID.
14576       Remove some issues which are no longer issues.
14577       Per review, rename and more completely document the timer
14578       information functions.
14579   </change>
14580   <change date="29 July 2003" version="v86">
14581       Non-spec visible change to XML controlled implementation:
14582         SetThreadLocalStorage must run in VM mode.
14583   </change>
14584   <change date="5 August 2003" version="0.1.87">
14585       Add GetErrorName.
14586       Add varargs warning to jvmtiExtensionEvent.
14587       Remove "const" on the jvmtiEnv* of jvmtiExtensionEvent.
14588       Remove unused can_get_exception_info capability.
14589       Pass jvmtiEnv* and JNIEnv* to the jvmtiStartFunction.
14590       Fix jvmtiExtensionFunctionInfo.func declared type.
14591       Extension function returns error code.
14592       Use new version numbering.
14593   </change>
14594   <change date="5 August 2003" version="0.2.88">
14595       Remove the ClassUnload event.
14596   </change>
14597   <change date="8 August 2003" version="0.2.89">
14598       Heap reference iterator callbacks return an enum that
14599       allows outgoing object references to be ignored.
14600       Allow JNIEnv as a param type to extension events/functions.
14601   </change>
14602   <change date="15 August 2003" version="0.2.90">
14603       Fix a typo.
14604   </change>
14605   <change date="2 September 2003" version="0.2.91">
14606       Remove all metadata functions: GetClassMetadata,
14607       GetFieldMetadata, and GetMethodMetadata.
14608   </change>
14609   <change date="1 October 2003" version="0.2.92">
14610       Mark the functions Allocate. Deallocate, RawMonitor*,
14611       SetEnvironmentLocalStorage, and GetEnvironmentLocalStorage
14612       as safe for use in heap callbacks and GC events.
14613   </change>
14614   <change date="24 November 2003" version="0.2.93">
14615       Add pass through opaque user data pointer to heap iterate
14616       functions and callbacks.
14617       In the CompiledMethodUnload event, send the code address.
14618       Add GarbageCollectionOccurred event.
14619       Add constant pool reference kind.
14620       Mark the functions CreateRawMonitor and DestroyRawMonitor
14621       as safe for use in heap callbacks and GC events.
14622       Clarify: VMDeath, GetCurrentThreadCpuTimerInfo,
14623       GetThreadCpuTimerInfo, IterateOverReachableObjects,
14624       IterateOverObjectsReachableFromObject, GetTime and
14625       JVMTI_ERROR_NULL_POINTER.
14626       Add missing errors to: GenerateEvents and
14627       AddToBootstrapClassLoaderSearch.
14628       Fix description of ClassFileLoadHook name parameter.
14629       In heap callbacks and GC/ObjectFree events, specify
14630       that only explicitly allowed functions can be called.
14631       Allow GetCurrentThreadCpuTimerInfo, GetCurrentThreadCpuTime,
14632       GetTimerInfo, and GetTime during callback.
14633       Allow calling SetTag/GetTag during the onload phase.
14634       SetEventNotificationMode, add: error attempted inappropriate
14635       thread level control.
14636       Remove jvmtiExceptionHandlerEntry.
14637       Fix handling of native methods on the stack --
14638       location_ptr param of GetFrameLocation, remove
14639       JVMTI_ERROR_OPAQUE_FRAME from GetFrameLocation,
14640       jvmtiFrameInfo.location, and jlocation.
14641       Remove typo (from JVMPI) implying that the MonitorWaited
14642       event is sent on sleep.
14643   </change>
14644   <change date="25 November 2003" version="0.2.94">
14645       Clarifications and typos.
14646   </change>
14647   <change date="3 December 2003" version="0.2.95">
14648       Allow NULL user_data in heap iterators.
14649   </change>
14650   <change date="28 January 2004" version="0.2.97">
14651       Add GetThreadState, deprecate GetThreadStatus.
14652   </change>
14653   <change date="29 January 2004" version="0.2.98">
14654       INVALID_SLOT and TYPE_MISMATCH errors should be optional.
14655   </change>
14656   <change date="12 February 2004" version="0.2.102">
14657       Remove MonitorContendedExit.
14658       Added JNIEnv parameter to VMObjectAlloc.
14659       Clarified definition of class_tag and referrer_index
14660       parameters to heap callbacks.
14661   </change>
14662   <change date="16 Febuary 2004" version="0.2.103">
14663       Document JAVA_TOOL_OPTIONS.
14664   </change>
14665   <change date="17 Febuary 2004" version="0.2.105">
14666       Divide start phase into primordial and start.
14667       Add VMStart event
14668       Change phase associations of functions and events.
14669   </change>
14670   <change date="18 Febuary 2004" version="0.3.6">
14671       Elide deprecated GetThreadStatus.
14672       Bump minor version, subtract 100 from micro version
14673   </change>
14674   <change date="18 Febuary 2004" version="0.3.7">
14675       Document that timer nanosecond values are unsigned.
14676       Clarify text having to do with native methods.
14677   </change>
14678   <change date="19 Febuary 2004" version="0.3.8">
14679       Fix typos.
14680       Remove elided deprecated GetThreadStatus.
14681   </change>
14682   <change date="23 Febuary 2004" version="0.3.9">
14683       Require NotifyFramePop to act on suspended threads.
14684   </change>
14685   <change date="24 Febuary 2004" version="0.3.10">
14686       Add capabilities
14687         (<internallink id="jvmtiCapabilities.can_redefine_any_class"
14688          ><code>can_redefine_any_class</code></internallink>
14689       and
14690          <internallink id="jvmtiCapabilities.can_generate_all_class_hook_events"
14691          ><code>can_generate_all_class_hook_events</code></internallink>)
14692       and an error (<errorlink id="JVMTI_ERROR_UNMODIFIABLE_CLASS"></errorlink>)
14693       which allow some classes to be unmodifiable.
14694   </change>
14695   <change date="28 Febuary 2004" version="0.3.11">
14696       Add JVMTI_ERROR_MUST_POSSESS_CAPABILITY to SetEventNotificationMode.
14697   </change>
14698   <change date="8 March 2004" version="0.3.12">
14699       Clarified CompiledMethodUnload so that it is clear the event
14700       may be posted after the class has been unloaded.
14701   </change>
14702   <change date="5 March 2004" version="0.3.13">
14703       Change the size parameter of VMObjectAlloc to jlong to match GetObjectSize.
14704   </change>
14705   <change date="13 March 2004" version="0.3.14">
14706       Added guideline for the use of the JNI FindClass function in event
14707       callback functions.
14708   </change>
14709   <change date="15 March 2004" version="0.3.15">
14710       Add GetAllStackTraces and GetThreadListStackTraces.
14711   </change>
14712   <change date="19 March 2004" version="0.3.16">
14713       ClassLoad and ClassPrepare events can be posted during start phase.
14714   </change>
14715   <change date="25 March 2004" version="0.3.17">
14716       Add JVMTI_ERROR_NATIVE_METHOD to GetLineNumberTable, GetLocalVariableTable,
14717       GetMaxLocals, GetArgumentsSize, GetMethodLocation, GetBytecodes.
14718   </change>
14719   <change date="29 March 2004" version="0.3.18">
14720       Return the timer kind in the timer information structure.
14721   </change>
14722   <change date="31 March 2004" version="0.3.19">
14723       Spec clarifications:
14724       JVMTI_THREAD_STATE_IN_NATIVE might not include JNI or <jvmti/>.
14725       ForceGarbageCollection does not run finalizers.
14726       The context of the specification is the Java platform.
14727       Warn about early instrumentation.
14728   </change>
14729   <change date="1 April 2004" version="0.3.20">
14730       Refinements to the above clarifications and
14731       Clarify that an error returned by Agent_OnLoad terminates the VM.
14732   </change>
14733   <change date="1 April 2004" version="0.3.21">
14734       Array class creation does not generate a class load event.
14735   </change>
14736   <change date="7 April 2004" version="0.3.22">
14737       Align thread state hierarchy more closely with java.lang.Thread.State.
14738   </change>
14739   <change date="12 April 2004" version="0.3.23">
14740       Clarify the documentation of thread state.
14741   </change>
14742   <change date="19 April 2004" version="0.3.24">
14743       Remove GarbageCollectionOccurred event -- can be done by agent.
14744   </change>
14745   <change date="22 April 2004" version="0.3.25">
14746       Define "command-line option".
14747   </change>
14748   <change date="29 April 2004" version="0.3.26">
14749       Describe the intended use of bytecode instrumentation.
14750       Fix description of extension event first parameter.
14751   </change>
14752   <change date="30 April 2004" version="0.3.27">
14753       Clarification and typos.
14754   </change>
14755   <change date="18 May 2004" version="0.3.28">
14756       Remove DataDumpRequest event.
14757   </change>
14758   <change date="18 May 2004" version="0.3.29">
14759       Clarify RawMonitorWait with zero timeout.
14760       Clarify thread state after RunAgentThread.
14761   </change>
14762   <change date="24 May 2004" version="0.3.30">
14763       Clean-up: fix bad/old links, etc.
14764   </change>
14765   <change date="30 May 2004" version="0.3.31">
14766       Clarifications including:
14767       All character strings are modified UTF-8.
14768       Agent thread visibiity.
14769       Meaning of obsolete method version.
14770       Thread invoking heap callbacks,
14771   </change>
14772   <change date="1 June 2004" version="1.0.32">
14773       Bump major.minor version numbers to "1.0".
14774   </change>
14775   <change date="2 June 2004" version="1.0.33">
14776       Clarify interaction between ForceGarbageCollection
14777       and ObjectFree.
14778   </change>
14779   <change date="6 June 2004" version="1.0.34">
14780       Restrict AddToBootstrapClassLoaderSearch and
14781       SetSystemProperty to the OnLoad phase only.
14782   </change>
14783   <change date="11 June 2004" version="1.0.35">
14784       Fix typo in SetTag.
14785   </change>
14786   <change date="18 June 2004" version="1.0.36">
14787       Fix trademarks.
14788       Add missing parameter in example GetThreadState usage.
14789   </change>
14790   <change date="4 August 2004" version="1.0.37">
14791       Copyright updates.
14792   </change>
14793   <change date="5 November 2004" version="1.0.38">
14794       Add missing function table layout.
14795       Add missing description of C++ member function format of functions.
14796       Clarify that name in CFLH can be NULL.
14797       Released as part of <tm>J2SE</tm> 5.0.
14798   </change>
14799   <change date="24 April 2005" version="1.1.47">
14800       Bump major.minor version numbers to "1.1".
14801       Add ForceEarlyReturn* functions.
14802       Add GetOwnedMonitorStackDepthInfo function.
14803       Add GetCurrentThread function.
14804       Add "since" version marker.
14805       Add AddToSystemClassLoaderSearch.
14806       Allow AddToBootstrapClassLoaderSearch be used in live phase.
14807       Fix historic rubbish in the descriptions of the heap_object_callback
14808       parameter of IterateOverHeap and IterateOverInstancesOfClass functions;
14809       disallow NULL for this parameter.
14810       Clarify, correct and make consistent: wording about current thread,
14811       opaque frames and insufficient number of frames in PopFrame.
14812       Consistently use "current frame" rather than "topmost".
14813       Clarify the JVMTI_ERROR_TYPE_MISMATCH errors in GetLocal* and SetLocal*
14814       by making them compatible with those in ForceEarlyReturn*.
14815       Many other clarifications and wording clean ups.
14816   </change>
14817   <change date="25 April 2005" version="1.1.48">
14818       Add GetConstantPool.
14819       Switch references to the first edition of the VM Spec, to the seconds edition.
14820   </change>
14821   <change date="26 April 2005" version="1.1.49">
14822       Clarify minor/major version order in GetConstantPool.
14823   </change>
14824   <change date="26 April 2005" version="1.1.50">
14825       Add SetNativeMethodPrefix and SetNativeMethodPrefixes.
14826       Reassign GetOwnedMonitorStackDepthInfo to position 153.
14827       Break out Class Loader Search in its own documentation category.
14828       Deal with overly long lines in XML source.
14829   </change>
14830   <change date="29 April 2005" version="1.1.51">
14831       Allow agents be started in the live phase.
14832       Added paragraph about deploying agents.
14833   </change>
14834   <change date="30 April 2005" version="1.1.52">
14835       Add specification description to SetNativeMethodPrefix(es).
14836       Better define the conditions on GetConstantPool.
14837   </change>
14838   <change date="30 April 2005" version="1.1.53">
14839       Break out the GetClassVersionNumber function from GetConstantPool.
14840       Clean-up the references to the VM Spec.
14841   </change>
14842   <change date="1 May 2005" version="1.1.54">
14843       Allow SetNativeMethodPrefix(es) in any phase.
14844       Add clarifications about the impact of redefinition on GetConstantPool.
14845   </change>
14846   <change date="2 May 2005" version="1.1.56">
14847       Various clarifications to SetNativeMethodPrefix(es).
14848   </change>
14849   <change date="2 May 2005" version="1.1.57">
14850       Add missing performance warning to the method entry event.
14851   </change>
14852   <change date="5 May 2005" version="1.1.58">
14853       Remove internal JVMDI support.
14854   </change>
14855   <change date="8 May 2005" version="1.1.59">
14856       Add <functionlink id="RetransformClasses"/>.
14857       Revamp the bytecode instrumentation documentation.
14858       Change <functionlink id="IsMethodObsolete"/> to no longer
14859       require the can_redefine_classes capability.
14860   </change>
14861   <change date="11 May 2005" version="1.1.63">
14862       Clarifications for retransformation.
14863   </change>
14864   <change date="11 May 2005" version="1.1.64">
14865       Clarifications for retransformation, per review.
14866       Lock "retransformation (in)capable" at class load enable time.
14867   </change>
14868   <change date="4 June 2005" version="1.1.67">
14869       Add new heap functionity which supports reporting primitive values,
14870       allows setting the referrer tag, and has more powerful filtering:
14871       FollowReferences, IterateThroughHeap, and their associated
14872       callbacks, structs, enums, and constants.
14873   </change>
14874   <change date="4 June 2005" version="1.1.68">
14875       Clarification.
14876   </change>
14877   <change date="6 June 2005" version="1.1.69">
14878       FollowReferences, IterateThroughHeap: Put callbacks in a struct;
14879       Add missing error codes; reduce bits in the visit control flags.
14880   </change>
14881   <change date="14 June 2005" version="1.1.70">
14882       More on new heap functionity: spec clean-up per review.
14883   </change>
14884   <change date="15 June 2005" version="1.1.71">
14885       More on new heap functionity: Rename old heap section to Heap (1.0).
14886   </change>
14887   <change date="21 June 2005" version="1.1.72">
14888       Fix typos.
14889   </change>
14890   <change date="27 June 2005" version="1.1.73">
14891       Make referrer info structure a union.
14892   </change>
14893   <change date="9 September 2005" version="1.1.74">
14894       In new heap functions:
14895       Add missing superclass reference kind.
14896       Use a single scheme for computing field indexes.
14897       Remove outdated references to struct based referrer info.
14898   </change>
14899   <change date="12 September 2005" version="1.1.75">
14900       Don't callback during FollowReferences on frivolous java.lang.Object superclass.
14901   </change>
14902   <change date="13 September 2005" version="1.1.76">
14903       In string primitive callback, length now Unicode length.
14904       In array and string primitive callbacks, value now "const".
14905       Note possible compiler impacts on setting JNI function table.
14906   </change>
14907   <change date="13 September 2005" version="1.1.77">
14908       GetClassVersionNumbers() and GetConstantPool() should return
14909       error on array or primitive class.
14910   </change>
14911   <change date="14 September 2005" version="1.1.78">
14912       Grammar fixes.
14913   </change>
14914   <change date="26 September 2005" version="1.1.79">
14915       Add IsModifiableClass query.
14916   </change>
14917   <change date="9 February 2006" version="1.1.81">
14918       Add referrer_class_tag parameter to jvmtiHeapReferenceCallback.
14919   </change>
14920   <change date="13 February 2006" version="1.1.82">
14921       Doc fixes: update can_redefine_any_class to include retransform.
14922       Clarify that exception events cover all Throwables.
14923       In GetStackTrace, no test is done for start_depth too big if start_depth is zero,
14924       Clarify fields reported in Primitive Field Callback -- static vs instance.
14925       Repair confusing names of heap types, including callback names.
14926       Require consistent usage of stack depth in the face of thread launch methods.
14927       Note incompatibility of <jvmti/> memory management with other systems.
14928   </change>
14929   <change date="14 February 2006" version="1.1.85">
14930       Fix typos and missing renames.
14931   </change>
14932   <change date="13 March 2006" version="1.1.86">
14933       Clarify that jmethodIDs and jfieldIDs can be saved.
14934       Clarify that Iterate Over Instances Of Class includes subclasses.
14935   </change>
14936   <change date="14 March 2006" version="1.1.87">
14937       Better phrasing.
14938   </change>
14939   <change date="16 March 2006" version="1.1.88">
14940       Match the referrer_index for static fields in Object Reference Callback
14941       with the Reference Implementation (and all other known implementations);
14942       that is, make it match the definition for instance fields.
14943       In GetThreadListStackTraces, add JVMTI_ERROR_INVALID_THREAD to cover
14944       an invalid thread in the list; and specify that not started threads
14945       return empty stacks.
14946   </change>
14947   <change date="17 March 2006" version="1.1.89">
14948       Typo.
14949   </change>
14950   <change date="25 March 2006" version="1.1.90">
14951       Typo.
14952   </change>
14953   <change date="6 April 2006" version="1.1.91">
14954       Remove restrictions on AddToBootstrapClassLoaderSearch and
14955       AddToSystemClassLoaderSearch.
14956   </change>
14957   <change date="1 May 2006" version="1.1.93">
14958       Changed spec to return -1 for monitor stack depth for the
14959       implementation which can not determine stack depth.
14960   </change>
14961   <change date="3 May 2006" version="1.1.94">
14962       Corrections for readability and accuracy courtesy of Alan Pratt of IBM.
14963       List the object relationships reported in FollowReferences.
14964   </change>
14965   <change date="5 May 2006" version="1.1.95">
14966       Clarify the object relationships reported in FollowReferences.
14967   </change>
14968   <change date="28 June 2006" version="1.1.98">
14969       Clarify DisposeEnvironment; add warning.
14970       Fix typos in SetLocalXXX "retrieve" => "set".
14971       Clarify that native method prefixes must remain set while used.
14972       Clarify that exactly one Agent_OnXXX is called per agent.
14973       Clarify that library loading is independent from start-up.
14974       Remove ambiguous reference to Agent_OnLoad in the Agent_OnUnload spec.
14975   </change>
14976   <change date="31 July 2006" version="1.1.99">
14977       Clarify the interaction between functions and exceptions.
14978       Clarify and give examples of field indices.
14979       Remove confusing "That is" sentence from MonitorWait and MonitorWaited events.
14980       Update links to point to Java 6.
14981   </change>
14982   <change date="6 August 2006" version="1.1.102">
14983       Add ResourceExhaustedEvent.
14984   </change>
14985   <change date="11 October 2012" version="1.2.2">
14986       Fixed the "HTTP" and "Missing Anchor" errors reported by the LinkCheck tool.
14987   </change>
14988   <change date="19 June 2013" version="1.2.3">
14989       Added support for statically linked agents.
14990   </change>
14991   <change date="13 October 2016" version="9.0.0">
14992       Support for modules:
14993        - The majorversion is 9 now
14994        - The ClassFileLoadHook events are not sent during the primordial phase anymore.
14995        - Allow CompiledMethodLoad events at start phase
14996        - Add new capabilities:
14997           - can_generate_early_vmstart
14998           - can_generate_early_class_hook_events
14999        - Add new functions:
15000           - GetAllModules
15001           - AddModuleReads, AddModuleExports, AddModuleOpens, AddModuleUses, AddModuleProvides
15002           - IsModifiableModule
15003       Clarified can_redefine_any_classes, can_retransform_any_classes and IsModifiableClass API to
15004       disallow some implementation defined classes.
15005   </change>
15006   <change date="12 February 2017" version="9.0.0">
15007       Minor update for GetCurrentThread function:
15008        - The function may return NULL in the start phase if the
15009          can_generate_early_vmstart capability is enabled.
15010   </change>
15011   <change date="7 February 2018" version="11.0.0">
15012       Minor update for new class file NestHost and NestMembers attributes:
15013         - Specify that RedefineClasses and RetransformClasses are not allowed
15014           to change the class file NestHost and NestMembers attributes.
15015         - Add new error JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_ATTRIBUTE_CHANGED
15016           that can be returned by RedefineClasses and RetransformClasses.
15017   </change>
15018   <change date="20 May 2019" version="13.0.0">
15019       Minor spec update for the capability "can_redefine_any_class".
15020       It now says:
15021        "RedefineClasses can be called on any modifiable class. See IsModifiableClass.
15022        (can_redefine_classes must also be set)"
15023   </change>
15024   <change date="5 June 2019" version="13.0.0">
15025       Minor PopFrame spec update:
15026         - The specified thread must be suspended or must be the current thread.
15027           (It was not allowed to be the current thread before.)
15028   </change>
15029   <change date="10 October 2019" version="14.0.0">
15030       Minor update for new class file Record attribute:
15031         - Specify that RedefineClasses and RetransformClasses are not allowed
15032           to change the class file Record attribute.
15033   </change>
15034   <change date="13 May 2020" version="15.0.0">
15035       Minor update for new class file PermittedSubclasses attribute:
15036         - Specify that RedefineClasses and RetransformClasses are not allowed
15037           to change the class file PermittedSubclasses attribute.
15038   </change>
15039   <change date="15 January 2021" version="17.0.0">
15040       Minor clarification in the section "Agent Shutdown" that says the
15041       implementation may choose to not call the Agent_OnUnload function
15042       if the Agent_OnAttach/Agent_OnAttach_L function reported an error. 
15043   </change>
15044   <change date="8 June 2021" version="17.0.0">
15045       Minor update to deprecate Heap functions 1.0.
15046   </change>
15047 </changehistory>
15048 
15049 </specification>
15050 <!-- Keep this comment at the end of the file
15051 Local variables:
15052 mode: sgml
15053 sgml-omittag:t
15054 sgml-shorttag:t
15055 sgml-namecase-general:t
15056 sgml-general-insert-case:lower
15057 sgml-minimize-attributes:nil
15058 sgml-always-quote-attributes:t
15059 sgml-indent-step:2
15060 sgml-indent-data:t
15061 sgml-parent-document:nil
15062 sgml-exposed-tags:nil
15063 sgml-local-catalogs:nil
15064 sgml-local-ecat-files:nil
15065 End:
15066 -->