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<h3 class="section">13.4 Debug Mode</h3>
<p>There are two additional support functions that allow the user to
interrogate where in the execution of a script Octave entered the debug
mode and to print the code in the script surrounding the point where
Octave entered debug mode.
<!-- dbwhere src/debug.cc -->
<p><a name="doc_002ddbwhere"></a>
<div class="defun">
— Loadable Function: <b>dbwhere</b> ()<var><a name="index-dbwhere-850"></a></var><br>
<blockquote><p>In debugging mode, report the current file and line number where
execution is stopped.
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<p class="noindent"><strong>See also:</strong> <a href="doc_002ddbstatus.html#doc_002ddbstatus">dbstatus</a>, <a href="doc_002ddbcont.html#doc_002ddbcont">dbcont</a>, <a href="doc_002ddbstep.html#doc_002ddbstep">dbstep</a>, <a href="doc_002ddbup.html#doc_002ddbup">dbup</a>.
</p></blockquote></div>
<!-- dbtype src/debug.cc -->
<p><a name="doc_002ddbtype"></a>
<div class="defun">
— Loadable Function: <b>dbtype</b> ()<var><a name="index-dbtype-851"></a></var><br>
— Loadable Function: <b>dbtype</b> (<var>"startl:endl"</var>)<var><a name="index-dbtype-852"></a></var><br>
— Loadable Function: <b>dbtype</b> (<var>"func"</var>)<var><a name="index-dbtype-853"></a></var><br>
— Loadable Function: <b>dbtype</b> (<var>"func", "startl:endl"</var>)<var><a name="index-dbtype-854"></a></var><br>
<blockquote><p>When in debugging mode and called with no arguments, list the script file
being debugged with line numbers. An optional range specification,
specified as a string, can be used to list only a portion of the file.
<p>When called with the name of a function, list that script file
with line numbers.
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<p class="noindent"><strong>See also:</strong> <a href="doc_002ddbstatus.html#doc_002ddbstatus">dbstatus</a>, <a href="doc_002ddbstop.html#doc_002ddbstop">dbstop</a>.
</p></blockquote></div>
<p>You may also use <code>isdebugmode</code> to determine whether the debugger is
currently active.
<!-- isdebugmode src/debug.cc -->
<p><a name="doc_002disdebugmode"></a>
<div class="defun">
— Loadable Function: <b>isdebugmode</b> ()<var><a name="index-isdebugmode-855"></a></var><br>
<blockquote><p>Return true if in debugging mode, otherwise false.
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<p class="noindent"><strong>See also:</strong> <a href="doc_002ddbwhere.html#doc_002ddbwhere">dbwhere</a>, <a href="doc_002ddbstack.html#doc_002ddbstack">dbstack</a>, <a href="doc_002ddbstatus.html#doc_002ddbstatus">dbstatus</a>.
</p></blockquote></div>
<p>Debug mode also allows single line stepping through a function using
the commands <code>dbstep</code>.
<!-- dbstep src/debug.cc -->
<p><a name="doc_002ddbstep"></a>
<div class="defun">
— Command: <b>dbstep</b><var><a name="index-dbstep-856"></a></var><br>
— Command: <b>dbstep</b><var> n<a name="index-dbstep-857"></a></var><br>
— Command: <b>dbstep</b><var> in<a name="index-dbstep-858"></a></var><br>
— Command: <b>dbstep</b><var> out<a name="index-dbstep-859"></a></var><br>
— Command: <b>dbnext</b><var> <small class="dots">...</small><a name="index-dbnext-860"></a></var><br>
<blockquote><p>In debugging mode, execute the next <var>n</var> lines of code.
If <var>n</var> is omitted, execute the next single line of code.
If the next line of code is itself defined in terms of an m-file remain in
the existing function.
<p>Using <code>dbstep in</code> will cause execution of the next line to step into
any m-files defined on the next line. Using <code>dbstep out</code> will cause
execution to continue until the current function returns.
<p><code>dbnext</code> is an alias for <code>dbstep</code>.
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<p class="noindent"><strong>See also:</strong> <a href="doc_002ddbcont.html#doc_002ddbcont">dbcont</a>, <a href="doc_002ddbquit.html#doc_002ddbquit">dbquit</a>.
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