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<h3 class="section">5.9 Unwind-protect</h3>
<p><a name="index-Unwind_002dprotect-8"></a>
Octave supports a limited form of exception handling modeled after the
unwind-protect form of Lisp. The general form of an
<code>unwind_protect</code> block looks like this:
<pre class="example"> unwind_protect
<var>body</var>
unwind_protect_cleanup
<var>cleanup</var>
end_unwind_protect
</pre>
<p class="noindent">Where <var>body</var> and <var>cleanup</var> are both optional and may contain any
Octave expressions or commands. The statements in <var>cleanup</var> are
guaranteed to be executed regardless of how control exits <var>body</var>.
<p>The <code>unwind_protect</code> statement is often used to reliably restore
the values of global variables that need to be temporarily changed.
<p><span class="sc">Matlab</span> can be made to do something similar with their
<code>OnCleanUp</code> function that was introduced in 2008a. Octave also has
<code>onCleanup</code> since version 3.4.0.
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