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<title>Command Settings (Debugging with GDB)</title>

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<a name="Command-Settings"></a>
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<hr>
<a name="Command-Settings-1"></a>
<h3 class="section">3.2 Command Settings</h3>
<a name="index-default-behavior-of-commands_002c-changing"></a>
<a name="index-default-settings_002c-changing"></a>

<p>Many commands change their behavior according to command-specific
variables or settings.  These settings can be changed with the
<code>set</code> subcommands.  For example, the <code>print</code> command
(see <a href="Data.html#Data">Examining Data</a>) prints arrays differently depending on
settings changeable with the commands <code>set print elements
NUMBER-OF-ELEMENTS</code> and <code>set print array-indexes</code>, among others.
</p>
<p>You can change these settings to your preference in the gdbinit files
loaded at <small>GDB</small> startup.  See <a href="Startup.html#Startup">Startup</a>.
</p>
<p>The settings can also be changed interactively during the debugging
session.  For example, to change the limit of array elements to print,
you can do the following:
</p><div class="smallexample">
<pre class="smallexample">(GDB) set print elements 10
(GDB) print some_array
$1 = {0, 10, 20, 30, 40, 50, 60, 70, 80, 90...}
</pre></div>

<p>The above <code>set print elements 10</code> command changes the number of
elements to print from the default of 200 to 10.  If you only intend
this limit of 10 to be used for printing <code>some_array</code>, then you
must restore the limit back to 200, with <code>set print elements
200</code>.
</p>
<p>Some commands allow overriding settings with command options.  For
example, the <code>print</code> command supports a number of options that
allow overriding relevant global print settings as set by <code>set
print</code> subcommands.  See <a href="Data.html#print-options">print options</a>.  The example above could be
rewritten as:
</p><div class="smallexample">
<pre class="smallexample">(GDB) print -elements 10 -- some_array
$1 = {0, 10, 20, 30, 40, 50, 60, 70, 80, 90...}
</pre></div>

<p>Alternatively, you can use the <code>with</code> command to change a setting
temporarily, for the duration of a command invocation.
</p>
<dl compact="compact">
<dd><a name="index-with-command"></a>
<a name="index-w-_0028with_0029"></a>
<a name="index-settings"></a>
<a name="index-temporarily-change-settings"></a>
</dd>
<dt><code>with <var>setting</var> [<var>value</var>] [-- <var>command</var>]</code></dt>
<dt><code>w <var>setting</var> [<var>value</var>] [-- <var>command</var>]</code></dt>
<dd><p>Temporarily set <var>setting</var> to <var>value</var> for the duration of
<var>command</var>.
</p>
<p><var>setting</var> is any setting you can change with the <code>set</code>
subcommands.  <var>value</var> is the value to assign to <code>setting</code>
while running <code>command</code>.
</p>
<p>If no <var>command</var> is provided, the last command executed is
repeated.
</p>
<p>If a <var>command</var> is provided, it must be preceded by a double dash
(<code>--</code>) separator.  This is required because some settings accept
free-form arguments, such as expressions or filenames.
</p>
<p>For example, the command
</p><div class="smallexample">
<pre class="smallexample">(GDB) with print array on -- print some_array
</pre></div>
<p>is equivalent to the following 3 commands:
</p><div class="smallexample">
<pre class="smallexample">(GDB) set print array on
(GDB) print some_array
(GDB) set print array off
</pre></div>

<p>The <code>with</code> command is particularly useful when you want to
override a setting while running user-defined commands, or commands
defined in Python or Guile.  See <a href="Extending-GDB.html#Extending-GDB">Extending GDB</a>.
</p>
<div class="smallexample">
<pre class="smallexample">(GDB) with print pretty on -- my_complex_command
</pre></div>

<p>To change several settings for the same command, you can nest
<code>with</code> commands.  For example, <code>with language ada -- with
print elements 10</code> temporarily changes the language to Ada and sets a
limit of 10 elements to print for arrays and strings.
</p>
</dd>
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