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<a name="Entering-Debug-Mode"></a>
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Next: <a href="Leaving-Debug-Mode.html#Leaving-Debug-Mode" accesskey="n" rel="next">Leaving Debug Mode</a>, Up: <a href="Debugging.html#Debugging" accesskey="u" rel="up">Debugging</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>
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<a name="Entering-Debug-Mode-1"></a>
<h3 class="section">13.1 Entering Debug Mode</h3>
<p>There are two basic means of interrupting the execution of an Octave
script. These are breakpoints (see <a href="Breakpoints.html#Breakpoints">Breakpoints</a>), discussed in the next
section, and interruption based on some condition.
</p>
<p>Octave supports three means to stop execution based on the values set in
the functions <code>debug_on_interrupt</code>, <code>debug_on_warning</code>, and
<code>debug_on_error</code>.
</p>
<a name="XREFdebug_005fon_005finterrupt"></a><dl>
<dt><a name="index-debug_005fon_005finterrupt"></a><em><var>val</var> =</em> <strong>debug_on_interrupt</strong> <em>()</em></dt>
<dt><a name="index-debug_005fon_005finterrupt-1"></a><em><var>old_val</var> =</em> <strong>debug_on_interrupt</strong> <em>(<var>new_val</var>)</em></dt>
<dt><a name="index-debug_005fon_005finterrupt-2"></a><em></em> <strong>debug_on_interrupt</strong> <em>(<var>new_val</var>, "local")</em></dt>
<dd><p>Query or set the internal variable that controls whether Octave will try
to enter debugging mode when it receives an interrupt signal (typically
generated with <kbd>C-c</kbd>).
</p>
<p>If a second interrupt signal is received before reaching the debugging mode,
a normal interrupt will occur.
</p>
<p>When called from inside a function with the <code>"local"</code> option, the
variable is changed locally for the function and any subroutines it calls.
The original variable value is restored when exiting the function.
</p>
<p><strong>See also:</strong> <a href="#XREFdebug_005fon_005ferror">debug_on_error</a>, <a href="#XREFdebug_005fon_005fwarning">debug_on_warning</a>.
</p></dd></dl>
<a name="XREFdebug_005fon_005fwarning"></a><dl>
<dt><a name="index-debug_005fon_005fwarning"></a><em><var>val</var> =</em> <strong>debug_on_warning</strong> <em>()</em></dt>
<dt><a name="index-debug_005fon_005fwarning-1"></a><em><var>old_val</var> =</em> <strong>debug_on_warning</strong> <em>(<var>new_val</var>)</em></dt>
<dt><a name="index-debug_005fon_005fwarning-2"></a><em></em> <strong>debug_on_warning</strong> <em>(<var>new_val</var>, "local")</em></dt>
<dd><p>Query or set the internal variable that controls whether Octave will try
to enter the debugger when a warning is encountered.
</p>
<p>When called from inside a function with the <code>"local"</code> option, the
variable is changed locally for the function and any subroutines it calls.
The original variable value is restored when exiting the function.
</p>
<p><strong>See also:</strong> <a href="#XREFdebug_005fon_005ferror">debug_on_error</a>, <a href="#XREFdebug_005fon_005finterrupt">debug_on_interrupt</a>.
</p></dd></dl>
<a name="XREFdebug_005fon_005ferror"></a><dl>
<dt><a name="index-debug_005fon_005ferror"></a><em><var>val</var> =</em> <strong>debug_on_error</strong> <em>()</em></dt>
<dt><a name="index-debug_005fon_005ferror-1"></a><em><var>old_val</var> =</em> <strong>debug_on_error</strong> <em>(<var>new_val</var>)</em></dt>
<dt><a name="index-debug_005fon_005ferror-2"></a><em></em> <strong>debug_on_error</strong> <em>(<var>new_val</var>, "local")</em></dt>
<dd><p>Query or set the internal variable that controls whether Octave will try
to enter the debugger when an error is encountered.
</p>
<p>This will also inhibit printing of the normal traceback message (you will
only see the top-level error message).
</p>
<p>When called from inside a function with the <code>"local"</code> option, the
variable is changed locally for the function and any subroutines it calls.
The original variable value is restored when exiting the function.
</p>
<p><strong>See also:</strong> <a href="#XREFdebug_005fon_005fwarning">debug_on_warning</a>, <a href="#XREFdebug_005fon_005finterrupt">debug_on_interrupt</a>.
</p></dd></dl>
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