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<h4 class="subsection">24.2.7 Miscellaneous Signals</h4>

<p>These signals are used for various other purposes.  In general, they
will not affect your program unless it explicitly uses them for something.

<!-- signal.h -->
<!-- POSIX.1 -->
<div class="defun">
&mdash; Macro: int <b>SIGUSR1</b><var><a name="index-SIGUSR1-2894"></a></var><br>
<blockquote><!-- signal.h -->
     <!-- POSIX.1 -->
   &mdash; Macro: int <b>SIGUSR2</b><var><a name="index-SIGUSR2-2895"></a></var><br>
<blockquote><p><a name="index-user-signals-2896"></a>The <code>SIGUSR1</code> and <code>SIGUSR2</code> signals are set aside for you to
use any way you want.  They're useful for simple interprocess
communication, if you write a signal handler for them in the program
that receives the signal.

        <p>There is an example showing the use of <code>SIGUSR1</code> and <code>SIGUSR2</code>
in <a href="Signaling-Another-Process.html#Signaling-Another-Process">Signaling Another Process</a>.

        <p>The default action is to terminate the process. 
</p></blockquote></div>

<!-- signal.h -->
<!-- BSD -->
<div class="defun">
&mdash; Macro: int <b>SIGWINCH</b><var><a name="index-SIGWINCH-2897"></a></var><br>
<blockquote><p>Window size change.  This is generated on some systems (including GNU)
when the terminal driver's record of the number of rows and columns on
the screen is changed.  The default action is to ignore it.

        <p>If a program does full-screen display, it should handle <code>SIGWINCH</code>. 
When the signal arrives, it should fetch the new screen size and
reformat its display accordingly. 
</p></blockquote></div>

<!-- signal.h -->
<!-- BSD -->
<div class="defun">
&mdash; Macro: int <b>SIGINFO</b><var><a name="index-SIGINFO-2898"></a></var><br>
<blockquote><p>Information request.  In 4.4 BSD and the GNU system, this signal is sent
to all the processes in the foreground process group of the controlling
terminal when the user types the STATUS character in canonical mode;
see <a href="Signal-Characters.html#Signal-Characters">Signal Characters</a>.

        <p>If the process is the leader of the process group, the default action is
to print some status information about the system and what the process
is doing.  Otherwise the default is to do nothing. 
</p></blockquote></div>

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