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<h3 class="section">8.12 <code>ALARM</code> — Execute a routine after a given delay</h3>
<p><a name="index-ALARM-387"></a><a name="index-delayed-execution-388"></a>
<dl>
<dt><em>Description</em>:<dd><code>ALARM(SECONDS, HANDLER [, STATUS])</code> causes external subroutine <var>HANDLER</var>
to be executed after a delay of <var>SECONDS</var> by using <code>alarm(2)</code> to
set up a signal and <code>signal(2)</code> to catch it. If <var>STATUS</var> is
supplied, it will be returned with the number of seconds remaining until
any previously scheduled alarm was due to be delivered, or zero if there
was no previously scheduled alarm.
<br><dt><em>Standard</em>:<dd>GNU extension
<br><dt><em>Class</em>:<dd>Subroutine
<br><dt><em>Syntax</em>:<dd><code>CALL ALARM(SECONDS, HANDLER [, STATUS])</code>
<br><dt><em>Arguments</em>:<dd>
<p><table summary=""><tr align="left"><td valign="top" width="15%"><var>SECONDS</var> </td><td valign="top" width="70%">The type of the argument shall be a scalar
<code>INTEGER</code>. It is <code>INTENT(IN)</code>.
<br></td></tr><tr align="left"><td valign="top" width="15%"><var>HANDLER</var> </td><td valign="top" width="70%">Signal handler (<code>INTEGER FUNCTION</code> or
<code>SUBROUTINE</code>) or dummy/global <code>INTEGER</code> scalar. The scalar
values may be either <code>SIG_IGN=1</code> to ignore the alarm generated
or <code>SIG_DFL=0</code> to set the default action. It is <code>INTENT(IN)</code>.
<br></td></tr><tr align="left"><td valign="top" width="15%"><var>STATUS</var> </td><td valign="top" width="70%">(Optional) <var>STATUS</var> shall be a scalar
variable of the default <code>INTEGER</code> kind. It is <code>INTENT(OUT)</code>.
<br></td></tr></table>
<br><dt><em>Example</em>:<dd>
<pre class="smallexample"> program test_alarm
external handler_print
integer i
call alarm (3, handler_print, i)
print *, i
call sleep(10)
end program test_alarm
</pre>
<p>This will cause the external routine <var>handler_print</var> to be called
after 3 seconds.
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