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Next:&nbsp;<a rel="next" accesskey="n" href="Pause-Problems.html#Pause-Problems">Pause Problems</a>,
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<h4 class="subsection">24.8.1 Using <code>pause</code></h4>

<p>The simple way to wait until a signal arrives is to call <code>pause</code>. 
Please read about its disadvantages, in the following section, before
you use it.

<!-- unistd.h -->
<!-- POSIX.1 -->
<div class="defun">
&mdash; Function: int <b>pause</b> ()<var><a name="index-pause-2981"></a></var><br>
<blockquote><p>The <code>pause</code> function suspends program execution until a signal
arrives whose action is either to execute a handler function, or to
terminate the process.

        <p>If the signal causes a handler function to be executed, then
<code>pause</code> returns.  This is considered an unsuccessful return (since
&ldquo;successful&rdquo; behavior would be to suspend the program forever), so the
return value is <code>-1</code>.  Even if you specify that other primitives
should resume when a system handler returns (see <a href="Interrupted-Primitives.html#Interrupted-Primitives">Interrupted Primitives</a>), this has no effect on <code>pause</code>; it always fails when a
signal is handled.

        <p>The following <code>errno</code> error conditions are defined for this function:

          <dl>
<dt><code>EINTR</code><dd>The function was interrupted by delivery of a signal. 
</dl>

        <p>If the signal causes program termination, <code>pause</code> doesn't return
(obviously).

        <p>This function is a cancellation point in multithreaded programs.  This
is a problem if the thread allocates some resources (like memory, file
descriptors, semaphores or whatever) at the time <code>pause</code> is
called.  If the thread gets cancelled these resources stay allocated
until the program ends.  To avoid this calls to <code>pause</code> should be
protected using cancellation handlers. 
<!-- ref pthread_cleanup_push / pthread_cleanup_pop -->

        <p>The <code>pause</code> function is declared in  <samp><span class="file">unistd.h</span></samp>. 
</p></blockquote></div>

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