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| <h3 class="section">3.3 Getting Help</h3> |
| |
| <p><a name="index-online-documentation-83"></a><a name="index-help-84"></a> |
| You can always ask <span class="sc">gdb</span> itself for information on its commands, |
| using the command <code>help</code>. |
| |
| |
| <a name="index-h-_0040r_007b_0028_0040code_007bhelp_007d_0029_007d-85"></a> |
| <dl><dt><code>help</code><dt><code>h</code><dd>You can use <code>help</code> (abbreviated <code>h</code>) with no arguments to |
| display a short list of named classes of commands: |
| |
| <pre class="smallexample"> (gdb) help |
| List of classes of commands: |
| |
| aliases -- Aliases of other commands |
| breakpoints -- Making program stop at certain points |
| data -- Examining data |
| files -- Specifying and examining files |
| internals -- Maintenance commands |
| obscure -- Obscure features |
| running -- Running the program |
| stack -- Examining the stack |
| status -- Status inquiries |
| support -- Support facilities |
| tracepoints -- Tracing of program execution without |
| stopping the program |
| user-defined -- User-defined commands |
| |
| Type "help" followed by a class name for a list of |
| commands in that class. |
| Type "help" followed by command name for full |
| documentation. |
| Command name abbreviations are allowed if unambiguous. |
| (gdb) |
| </pre> |
| <!-- the above line break eliminates huge line overfull... --> |
| <br><dt><code>help </code><var>class</var><dd>Using one of the general help classes as an argument, you can get a |
| list of the individual commands in that class. For example, here is the |
| help display for the class <code>status</code>: |
| |
| <pre class="smallexample"> (gdb) help status |
| Status inquiries. |
| |
| List of commands: |
| |
| <!-- Line break in "show" line falsifies real output, but needed --> |
| <!-- to fit in smallbook page size. --> |
| info -- Generic command for showing things |
| about the program being debugged |
| show -- Generic command for showing things |
| about the debugger |
| |
| Type "help" followed by command name for full |
| documentation. |
| Command name abbreviations are allowed if unambiguous. |
| (gdb) |
| </pre> |
| <br><dt><code>help </code><var>command</var><dd>With a command name as <code>help</code> argument, <span class="sc">gdb</span> displays a |
| short paragraph on how to use that command. |
| |
| <p><a name="index-apropos-86"></a><br><dt><code>apropos </code><var>args</var><dd>The <code>apropos</code> command searches through all of the <span class="sc">gdb</span> |
| commands, and their documentation, for the regular expression specified in |
| <var>args</var>. It prints out all matches found. For example: |
| |
| <pre class="smallexample"> apropos reload |
| </pre> |
| <p class="noindent">results in: |
| |
| <pre class="smallexample"> <!-- @group --> |
| set symbol-reloading -- Set dynamic symbol table reloading |
| multiple times in one run |
| show symbol-reloading -- Show dynamic symbol table reloading |
| multiple times in one run |
| <!-- @end group --> |
| </pre> |
| <p><a name="index-complete-87"></a><br><dt><code>complete </code><var>args</var><dd>The <code>complete </code><var>args</var> command lists all the possible completions |
| for the beginning of a command. Use <var>args</var> to specify the beginning of the |
| command you want completed. For example: |
| |
| <pre class="smallexample"> complete i |
| </pre> |
| <p class="noindent">results in: |
| |
| <pre class="smallexample"> if |
| ignore |
| info |
| inspect |
| </pre> |
| <p class="noindent">This is intended for use by <span class="sc">gnu</span> Emacs. |
| </dl> |
| |
| <p>In addition to <code>help</code>, you can use the <span class="sc">gdb</span> commands <code>info</code> |
| and <code>show</code> to inquire about the state of your program, or the state |
| of <span class="sc">gdb</span> itself. Each command supports many topics of inquiry; this |
| manual introduces each of them in the appropriate context. The listings |
| under <code>info</code> and under <code>show</code> in the Index point to |
| all the sub-commands. See <a href="GDB-Index.html#GDB-Index">GDB Index</a>. |
| |
| <!-- @group --> |
| |
| <a name="index-info-88"></a> |
| <a name="index-i-_0040r_007b_0028_0040code_007binfo_007d_0029_007d-89"></a> |
| <dl><dt><code>info</code><dd>This command (abbreviated <code>i</code>) is for describing the state of your |
| program. For example, you can show the arguments passed to a function |
| with <code>info args</code>, list the registers currently in use with <code>info |
| registers</code>, or list the breakpoints you have set with <code>info breakpoints</code>. |
| You can get a complete list of the <code>info</code> sub-commands with |
| <code>help info</code><!-- /@w -->. |
| |
| <p><a name="index-set-90"></a><br><dt><code>set</code><dd>You can assign the result of an expression to an environment variable with |
| <code>set</code>. For example, you can set the <span class="sc">gdb</span> prompt to a $-sign with |
| <code>set prompt $</code>. |
| |
| <p><a name="index-show-91"></a><br><dt><code>show</code><dd>In contrast to <code>info</code>, <code>show</code> is for describing the state of |
| <span class="sc">gdb</span> itself. |
| You can change most of the things you can <code>show</code>, by using the |
| related command <code>set</code>; for example, you can control what number |
| system is used for displays with <code>set radix</code>, or simply inquire |
| which is currently in use with <code>show radix</code>. |
| |
| <p><a name="index-info-set-92"></a>To display all the settable parameters and their current |
| values, you can use <code>show</code> with no arguments; you may also use |
| <code>info set</code>. Both commands produce the same display. |
| <!-- FIXME: "info set" violates the rule that "info" is for state of --> |
| <!-- FIXME...program. Ck w/ GNU: "info set" to be called something else, --> |
| <!-- FIXME...or change desc of rule-eg "state of prog and debugging session"? --> |
| </dl> |
| <!-- @end group --> |
| |
| <p>Here are three miscellaneous <code>show</code> subcommands, all of which are |
| exceptional in lacking corresponding <code>set</code> commands: |
| |
| |
| <a name="index-show-version-93"></a> |
| <a name="index-g_t_0040value_007bGDBN_007d-version-number-94"></a> |
| <dl><dt><code>show version</code><dd>Show what version of <span class="sc">gdb</span> is running. You should include this |
| information in <span class="sc">gdb</span> bug-reports. If multiple versions of |
| <span class="sc">gdb</span> are in use at your site, you may need to determine which |
| version of <span class="sc">gdb</span> you are running; as <span class="sc">gdb</span> evolves, new |
| commands are introduced, and old ones may wither away. Also, many |
| system vendors ship variant versions of <span class="sc">gdb</span>, and there are |
| variant versions of <span class="sc">gdb</span> in <span class="sc">gnu</span>/Linux distributions as well. |
| The version number is the same as the one announced when you start |
| <span class="sc">gdb</span>. |
| |
| <p><a name="index-show-copying-95"></a><a name="index-info-copying-96"></a><a name="index-display-_0040value_007bGDBN_007d-copyright-97"></a><br><dt><code>show copying</code><dt><code>info copying</code><dd>Display information about permission for copying <span class="sc">gdb</span>. |
| |
| <p><a name="index-show-warranty-98"></a><a name="index-info-warranty-99"></a><br><dt><code>show warranty</code><dt><code>info warranty</code><dd>Display the <span class="sc">gnu</span> “NO WARRANTY” statement, or a warranty, |
| if your version of <span class="sc">gdb</span> comes with one. |
| |
| </dl> |
| |
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| |
