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| <a name="Skipping-Over-Functions-and-Files"></a> |
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| <h3 class="section">5.3 Skipping Over Functions and Files</h3> |
| |
| <p><a name="index-skipping-over-functions-and-files-376"></a> |
| The program you are debugging may contain some functions which are |
| uninteresting to debug. The <code>skip</code> command lets you tell <span class="sc">gdb</span> to |
| skip a function, all functions in a file or a particular function in |
| a particular file when stepping. |
| |
| <p>For example, consider the following C function: |
| |
| <pre class="smallexample"> 101 int func() |
| 102 { |
| 103 foo(boring()); |
| 104 bar(boring()); |
| 105 } |
| </pre> |
| <p class="noindent">Suppose you wish to step into the functions <code>foo</code> and <code>bar</code>, but you |
| are not interested in stepping through <code>boring</code>. If you run <code>step</code> |
| at line 103, you'll enter <code>boring()</code>, but if you run <code>next</code>, you'll |
| step over both <code>foo</code> and <code>boring</code>! |
| |
| <p>One solution is to <code>step</code> into <code>boring</code> and use the <code>finish</code> |
| command to immediately exit it. But this can become tedious if <code>boring</code> |
| is called from many places. |
| |
| <p>A more flexible solution is to execute <kbd>skip boring</kbd>. This instructs |
| <span class="sc">gdb</span> never to step into <code>boring</code>. Now when you execute |
| <code>step</code> at line 103, you'll step over <code>boring</code> and directly into |
| <code>foo</code>. |
| |
| <p>Functions may be skipped by providing either a function name, linespec |
| (see <a href="Specify-Location.html#Specify-Location">Specify Location</a>), regular expression that matches the function's |
| name, file name or a <code>glob</code>-style pattern that matches the file name. |
| |
| <p>On Posix systems the form of the regular expression is |
| “Extended Regular Expressions”. See for example ‘<samp><span class="samp">man 7 regex</span></samp>’ |
| on <span class="sc">gnu</span>/Linux systems. On non-Posix systems the form of the regular |
| expression is whatever is provided by the <code>regcomp</code> function of |
| the underlying system. |
| See for example ‘<samp><span class="samp">man 7 glob</span></samp>’ on <span class="sc">gnu</span>/Linux systems for a |
| description of <code>glob</code>-style patterns. |
| |
| |
| <a name="index-skip-377"></a> |
| <dl><dt><code>skip </code><span class="roman">[</span><var>options</var><span class="roman">]</span><dd>The basic form of the <code>skip</code> command takes zero or more options |
| that specify what to skip. |
| The <var>options</var> argument is any useful combination of the following: |
| |
| <dl> |
| <dt><code>-file </code><var>file</var><dt><code>-fi </code><var>file</var><dd>Functions in <var>file</var> will be skipped over when stepping. |
| |
| <br><dt><code>-gfile </code><var>file-glob-pattern</var><dt><code>-gfi </code><var>file-glob-pattern</var><dd><a name="index-skipping-over-files-via-glob_002dstyle-patterns-378"></a>Functions in files matching <var>file-glob-pattern</var> will be skipped |
| over when stepping. |
| |
| <pre class="smallexample"> (gdb) skip -gfi utils/*.c |
| </pre> |
| <br><dt><code>-function </code><var>linespec</var><dt><code>-fu </code><var>linespec</var><dd>Functions named by <var>linespec</var> or the function containing the line |
| named by <var>linespec</var> will be skipped over when stepping. |
| See <a href="Specify-Location.html#Specify-Location">Specify Location</a>. |
| |
| <br><dt><code>-rfunction </code><var>regexp</var><dt><code>-rfu </code><var>regexp</var><dd><a name="index-skipping-over-functions-via-regular-expressions-379"></a>Functions whose name matches <var>regexp</var> will be skipped over when stepping. |
| |
| <p>This form is useful for complex function names. |
| For example, there is generally no need to step into C<tt>++</tt> <code>std::string</code> |
| constructors or destructors. Plus with C<tt>++</tt> templates it can be hard to |
| write out the full name of the function, and often it doesn't matter what |
| the template arguments are. Specifying the function to be skipped as a |
| regular expression makes this easier. |
| |
| <pre class="smallexample"> (gdb) skip -rfu ^std::(allocator|basic_string)<.*>::~?\1 *\( |
| </pre> |
| <p>If you want to skip every templated C<tt>++</tt> constructor and destructor |
| in the <code>std</code> namespace you can do: |
| |
| <pre class="smallexample"> (gdb) skip -rfu ^std::([a-zA-z0-9_]+)<.*>::~?\1 *\( |
| </pre> |
| </dl> |
| |
| <p>If no options are specified, the function you're currently debugging |
| will be skipped. |
| |
| <p><a name="index-skip-function-380"></a><br><dt><code>skip function </code><span class="roman">[</span><var>linespec</var><span class="roman">]</span><dd>After running this command, the function named by <var>linespec</var> or the |
| function containing the line named by <var>linespec</var> will be skipped over when |
| stepping. See <a href="Specify-Location.html#Specify-Location">Specify Location</a>. |
| |
| <p>If you do not specify <var>linespec</var>, the function you're currently debugging |
| will be skipped. |
| |
| <p>(If you have a function called <code>file</code> that you want to skip, use |
| <kbd>skip function file</kbd>.) |
| |
| <p><a name="index-skip-file-381"></a><br><dt><code>skip file </code><span class="roman">[</span><var>filename</var><span class="roman">]</span><dd>After running this command, any function whose source lives in <var>filename</var> |
| will be skipped over when stepping. |
| |
| <pre class="smallexample"> (gdb) skip file boring.c |
| File boring.c will be skipped when stepping. |
| </pre> |
| <p>If you do not specify <var>filename</var>, functions whose source lives in the file |
| you're currently debugging will be skipped. |
| </dl> |
| |
| <p>Skips can be listed, deleted, disabled, and enabled, much like breakpoints. |
| These are the commands for managing your list of skips: |
| |
| |
| <a name="index-info-skip-382"></a> |
| <dl><dt><code>info skip </code><span class="roman">[</span><var>range</var><span class="roman">]</span><dd>Print details about the specified skip(s). If <var>range</var> is not specified, |
| print a table with details about all functions and files marked for skipping. |
| <code>info skip</code> prints the following information about each skip: |
| |
| <dl> |
| <dt><em>Identifier</em><dd>A number identifying this skip. |
| <br><dt><em>Enabled or Disabled</em><dd>Enabled skips are marked with ‘<samp><span class="samp">y</span></samp>’. |
| Disabled skips are marked with ‘<samp><span class="samp">n</span></samp>’. |
| <br><dt><em>Glob</em><dd>If the file name is a ‘<samp><span class="samp">glob</span></samp>’ pattern this is ‘<samp><span class="samp">y</span></samp>’. |
| Otherwise it is ‘<samp><span class="samp">n</span></samp>’. |
| <br><dt><em>File</em><dd>The name or ‘<samp><span class="samp">glob</span></samp>’ pattern of the file to be skipped. |
| If no file is specified this is ‘<samp><span class="samp"><none></span></samp>’. |
| <br><dt><em>RE</em><dd>If the function name is a ‘<samp><span class="samp">regular expression</span></samp>’ this is ‘<samp><span class="samp">y</span></samp>’. |
| Otherwise it is ‘<samp><span class="samp">n</span></samp>’. |
| <br><dt><em>Function</em><dd>The name or regular expression of the function to skip. |
| If no function is specified this is ‘<samp><span class="samp"><none></span></samp>’. |
| </dl> |
| |
| <p><a name="index-skip-delete-383"></a><br><dt><code>skip delete </code><span class="roman">[</span><var>range</var><span class="roman">]</span><dd>Delete the specified skip(s). If <var>range</var> is not specified, delete all |
| skips. |
| |
| <p><a name="index-skip-enable-384"></a><br><dt><code>skip enable </code><span class="roman">[</span><var>range</var><span class="roman">]</span><dd>Enable the specified skip(s). If <var>range</var> is not specified, enable all |
| skips. |
| |
| <p><a name="index-skip-disable-385"></a><br><dt><code>skip disable </code><span class="roman">[</span><var>range</var><span class="roman">]</span><dd>Disable the specified skip(s). If <var>range</var> is not specified, disable all |
| skips. |
| |
| <p><a name="index-set-debug-skip-386"></a><br><dt><code>set debug skip </code><span class="roman">[</span><code>on|off</code><span class="roman">]</span><dd>Set whether to print the debug output about skipping files and functions. |
| |
| <p><a name="index-show-debug-skip-387"></a><br><dt><code>show debug skip</code><dd>Show whether the debug output about skipping files and functions is printed. |
| |
| </dl> |
| |
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