<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <!-- Copyright (C) 1988-2019 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with the Invariant Sections being "Free Software" and "Free Software Needs Free Documentation", with the Front-Cover Texts being "A GNU Manual," and with the Back-Cover Texts as in (a) below. (a) The FSF's Back-Cover Text is: "You are free to copy and modify this GNU Manual. Buying copies from GNU Press supports the FSF in developing GNU and promoting software freedom." --> <!-- Created by GNU Texinfo 6.4, http://www.gnu.org/software/texinfo/ --> <head> <title>GDB/MI Support Commands (Debugging with GDB)</title> <meta name="description" content="GDB/MI Support Commands (Debugging with GDB)"> <meta name="keywords" content="GDB/MI Support Commands (Debugging with GDB)"> <meta name="resource-type" content="document"> <meta name="distribution" content="global"> <meta name="Generator" content="makeinfo"> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <link href="index.html#Top" rel="start" title="Top"> <link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index"> <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> <link href="GDB_002fMI.html#GDB_002fMI" rel="up" title="GDB/MI"> <link href="GDB_002fMI-Miscellaneous-Commands.html#GDB_002fMI-Miscellaneous-Commands" rel="next" title="GDB/MI Miscellaneous Commands"> <link href="GDB_002fMI-Ada-Exceptions-Commands.html#GDB_002fMI-Ada-Exceptions-Commands" rel="prev" title="GDB/MI Ada Exceptions Commands"> <style type="text/css"> <!-- a.summary-letter {text-decoration: none} blockquote.indentedblock {margin-right: 0em} blockquote.smallindentedblock {margin-right: 0em; font-size: smaller} blockquote.smallquotation {font-size: smaller} div.display {margin-left: 3.2em} div.example {margin-left: 3.2em} div.lisp {margin-left: 3.2em} div.smalldisplay {margin-left: 3.2em} div.smallexample {margin-left: 3.2em} div.smalllisp {margin-left: 3.2em} kbd {font-style: oblique} pre.display {font-family: inherit} pre.format {font-family: inherit} pre.menu-comment {font-family: serif} pre.menu-preformatted {font-family: serif} pre.smalldisplay {font-family: inherit; font-size: smaller} pre.smallexample {font-size: smaller} pre.smallformat {font-family: inherit; font-size: smaller} pre.smalllisp {font-size: smaller} span.nolinebreak {white-space: nowrap} span.roman {font-family: initial; font-weight: normal} span.sansserif {font-family: sans-serif; font-weight: normal} ul.no-bullet {list-style: none} --> </style> </head> <body lang="en"> <a name="GDB_002fMI-Support-Commands"></a> <div class="header"> <p> Next: <a href="GDB_002fMI-Miscellaneous-Commands.html#GDB_002fMI-Miscellaneous-Commands" accesskey="n" rel="next">GDB/MI Miscellaneous Commands</a>, Previous: <a href="GDB_002fMI-Ada-Exceptions-Commands.html#GDB_002fMI-Ada-Exceptions-Commands" accesskey="p" rel="prev">GDB/MI Ada Exceptions Commands</a>, Up: <a href="GDB_002fMI.html#GDB_002fMI" accesskey="u" rel="up">GDB/MI</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p> </div> <hr> <a name="GDB_002fMI-Support-Commands-1"></a> <h3 class="section">27.23 <small>GDB/MI</small> Support Commands</h3> <p>Since new commands and features get regularly added to <small>GDB/MI</small>, some commands are available to help front-ends query the debugger about support for these capabilities. Similarly, it is also possible to query <small>GDB</small> about target support of certain features. </p> <a name="The-_002dinfo_002dgdb_002dmi_002dcommand-Command"></a> <h4 class="subheading">The <code>-info-gdb-mi-command</code> Command</h4> <a name="index-_002dinfo_002dgdb_002dmi_002dcommand"></a> <a name="index-_002dinfo_002dgdb_002dmi_002dcommand-1"></a> <a name="Synopsis-94"></a> <h4 class="subsubheading">Synopsis</h4> <div class="smallexample"> <pre class="smallexample"> -info-gdb-mi-command <var>cmd_name</var> </pre></div> <p>Query support for the <small>GDB/MI</small> command named <var>cmd_name</var>. </p> <p>Note that the dash (<code>-</code>) starting all <small>GDB/MI</small> commands is technically not part of the command name (see <a href="GDB_002fMI-Input-Syntax.html#GDB_002fMI-Input-Syntax">GDB/MI Input Syntax</a>), and thus should be omitted in <var>cmd_name</var>. However, for ease of use, this command also accepts the form with the leading dash. </p> <a name="GDB-Command-76"></a> <h4 class="subsubheading"><small>GDB</small> Command</h4> <p>There is no corresponding <small>GDB</small> command. </p> <a name="Result-8"></a> <h4 class="subsubheading">Result</h4> <p>The result is a tuple. There is currently only one field: </p> <dl compact="compact"> <dt>‘<samp>exists</samp>’</dt> <dd><p>This field is equal to <code>"true"</code> if the <small>GDB/MI</small> command exists, <code>"false"</code> otherwise. </p> </dd> </dl> <a name="Example-76"></a> <h4 class="subsubheading">Example</h4> <p>Here is an example where the <small>GDB/MI</small> command does not exist: </p> <div class="smallexample"> <pre class="smallexample">-info-gdb-mi-command unsupported-command ^done,command={exists="false"} </pre></div> <p>And here is an example where the <small>GDB/MI</small> command is known to the debugger: </p> <div class="smallexample"> <pre class="smallexample">-info-gdb-mi-command symbol-list-lines ^done,command={exists="true"} </pre></div> <a name="The-_002dlist_002dfeatures-Command"></a> <h4 class="subheading">The <code>-list-features</code> Command</h4> <a name="index-_002dlist_002dfeatures"></a> <a name="index-supported-GDB_002fMI-features_002c-list"></a> <p>Returns a list of particular features of the MI protocol that this version of gdb implements. A feature can be a command, or a new field in an output of some command, or even an important bugfix. While a frontend can sometimes detect presence of a feature at runtime, it is easier to perform detection at debugger startup. </p> <p>The command returns a list of strings, with each string naming an available feature. Each returned string is just a name, it does not have any internal structure. The list of possible feature names is given below. </p> <p>Example output: </p> <div class="smallexample"> <pre class="smallexample">(gdb) -list-features ^done,result=["feature1","feature2"] </pre></div> <p>The current list of features is: </p> <dl compact="compact"> <dt>‘<samp>frozen-varobjs</samp>’ <a name="index-frozen_002dvarobjs"></a> </dt> <dd><p>Indicates support for the <code>-var-set-frozen</code> command, as well as possible presense of the <code>frozen</code> field in the output of <code>-varobj-create</code>. </p></dd> <dt>‘<samp>pending-breakpoints</samp>’ <a name="index-pending_002dbreakpoints"></a> </dt> <dd><p>Indicates support for the <samp>-f</samp> option to the <code>-break-insert</code> command. </p></dd> <dt>‘<samp>python</samp>’ <a name="index-python"></a> </dt> <dd><p>Indicates Python scripting support, Python-based pretty-printing commands, and possible presence of the ‘<samp>display_hint</samp>’ field in the output of <code>-var-list-children</code> </p></dd> <dt>‘<samp>thread-info</samp>’ <a name="index-thread_002dinfo"></a> </dt> <dd><p>Indicates support for the <code>-thread-info</code> command. </p></dd> <dt>‘<samp>data-read-memory-bytes</samp>’ <a name="index-data_002dread_002dmemory_002dbytes"></a> </dt> <dd><p>Indicates support for the <code>-data-read-memory-bytes</code> and the <code>-data-write-memory-bytes</code> commands. </p></dd> <dt>‘<samp>breakpoint-notifications</samp>’ <a name="index-breakpoint_002dnotifications"></a> </dt> <dd><p>Indicates that changes to breakpoints and breakpoints created via the CLI will be announced via async records. </p></dd> <dt>‘<samp>ada-task-info</samp>’ <a name="index-ada_002dtask_002dinfo"></a> </dt> <dd><p>Indicates support for the <code>-ada-task-info</code> command. </p></dd> <dt>‘<samp>language-option</samp>’ <a name="index-language_002doption"></a> </dt> <dd><p>Indicates that all <small>GDB/MI</small> commands accept the <samp>--language</samp> option (see <a href="Context-management.html#Context-management">Context management</a>). </p></dd> <dt>‘<samp>info-gdb-mi-command</samp>’ <a name="index-info_002dgdb_002dmi_002dcommand"></a> </dt> <dd><p>Indicates support for the <code>-info-gdb-mi-command</code> command. </p></dd> <dt>‘<samp>undefined-command-error-code</samp>’ <a name="index-undefined_002dcommand_002derror_002dcode"></a> </dt> <dd><p>Indicates support for the "undefined-command" error code in error result records, produced when trying to execute an undefined <small>GDB/MI</small> command (see <a href="GDB_002fMI-Result-Records.html#GDB_002fMI-Result-Records">GDB/MI Result Records</a>). </p></dd> <dt>‘<samp>exec-run-start-option</samp>’ <a name="index-exec_002drun_002dstart_002doption"></a> </dt> <dd><p>Indicates that the <code>-exec-run</code> command supports the <samp>--start</samp> option (see <a href="GDB_002fMI-Program-Execution.html#GDB_002fMI-Program-Execution">GDB/MI Program Execution</a>). </p></dd> <dt>‘<samp>data-disassemble-a-option</samp>’ <a name="index-data_002ddisassemble_002da_002doption"></a> </dt> <dd><p>Indicates that the <code>-data-disassemble</code> command supports the <samp>-a</samp> option (see <a href="GDB_002fMI-Data-Manipulation.html#GDB_002fMI-Data-Manipulation">GDB/MI Data Manipulation</a>). </p></dd> </dl> <a name="The-_002dlist_002dtarget_002dfeatures-Command"></a> <h4 class="subheading">The <code>-list-target-features</code> Command</h4> <a name="index-_002dlist_002dtarget_002dfeatures"></a> <p>Returns a list of particular features that are supported by the target. Those features affect the permitted MI commands, but unlike the features reported by the <code>-list-features</code> command, the features depend on which target GDB is using at the moment. Whenever a target can change, due to commands such as <code>-target-select</code>, <code>-target-attach</code> or <code>-exec-run</code>, the list of target features may change, and the frontend should obtain it again. Example output: </p> <div class="smallexample"> <pre class="smallexample">(gdb) -list-target-features ^done,result=["async"] </pre></div> <p>The current list of features is: </p> <dl compact="compact"> <dt>‘<samp>async</samp>’</dt> <dd><p>Indicates that the target is capable of asynchronous command execution, which means that <small>GDB</small> will accept further commands while the target is running. </p> </dd> <dt>‘<samp>reverse</samp>’</dt> <dd><p>Indicates that the target is capable of reverse execution. See <a href="Reverse-Execution.html#Reverse-Execution">Reverse Execution</a>, for more information. </p> </dd> </dl> <hr> <div class="header"> <p> Next: <a href="GDB_002fMI-Miscellaneous-Commands.html#GDB_002fMI-Miscellaneous-Commands" accesskey="n" rel="next">GDB/MI Miscellaneous Commands</a>, Previous: <a href="GDB_002fMI-Ada-Exceptions-Commands.html#GDB_002fMI-Ada-Exceptions-Commands" accesskey="p" rel="prev">GDB/MI Ada Exceptions Commands</a>, Up: <a href="GDB_002fMI.html#GDB_002fMI" accesskey="u" rel="up">GDB/MI</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p> </div> </body> </html>