156 lines
5.8 KiB
HTML
156 lines
5.8 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<link type="text/css" rel="stylesheet" href="style.css"><!-- Generated by The Open Group's rhtm tool v1.2.1 -->
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<!-- Copyright (c) 2001 The Open Group, All Rights Reserved -->
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<title>ualarm</title>
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</head>
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<body bgcolor="white">
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<script type="text/javascript" language="JavaScript" src="../jscript/codes.js">
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<basefont size="3"> <a name="ualarm"></a> <a name="tag_03_796"></a><!-- ualarm -->
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<!--header start-->
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<center><font size="2">The Open Group Base Specifications Issue 6<br>
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IEEE Std 1003.1-2001<br>
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Copyright © 2001 The IEEE and The Open Group, All Rights reserved.</font></center>
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<!--header end-->
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<hr size="2" noshade>
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<h4><a name="tag_03_796_01"></a>NAME</h4>
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<blockquote>ualarm - set the interval timer</blockquote>
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<h4><a name="tag_03_796_02"></a>SYNOPSIS</h4>
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<blockquote class="synopsis">
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<div class="box"><code><tt><sup>[<a href="javascript:open_code('OB XSI')">OB XSI</a>]</sup> <img src="../images/opt-start.gif" alt=
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"[Option Start]" border="0"> #include <<a href="../basedefs/unistd.h.html">unistd.h</a>><br>
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<br>
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useconds_t ualarm(useconds_t</tt> <i>useconds</i><tt>, useconds_t</tt> <i>interval</i><tt>); <img src="../images/opt-end.gif" alt=
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"[Option End]" border="0"></tt></code></div>
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<tt><br>
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</tt></blockquote>
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<h4><a name="tag_03_796_03"></a>DESCRIPTION</h4>
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<blockquote>
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<p>The <i>ualarm</i>() function shall cause the SIGALRM signal to be generated for the calling process after the number of realtime
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microseconds specified by the <i>useconds</i> argument has elapsed. When the <i>interval</i> argument is non-zero, repeated timeout
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notification occurs with a period in microseconds specified by the <i>interval</i> argument. If the notification signal, SIGALRM,
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is not caught or ignored, the calling process is terminated.</p>
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<p>Implementations may place limitations on the granularity of timer values. For each interval timer, if the requested timer value
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requires a finer granularity than the implementation supports, the actual timer value shall be rounded up to the next supported
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value.</p>
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<p>Interactions between <i>ualarm</i>() and any of the following are unspecified:</p>
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<blockquote>
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<pre>
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<a href="../functions/alarm.html"><i>alarm</i>()</a>
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<a href="../functions/nanosleep.html"><i>nanosleep</i>()</a>
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<a href="../functions/setitimer.html"><i>setitimer</i>()</a>
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<a href="../functions/timer_create.html"><i>timer_create</i>()</a>
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<a href="../functions/timer_delete.html"><i>timer_delete</i>()</a>
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<a href="../functions/timer_getoverrun.html"><i>timer_getoverrun</i>()</a>
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<a href="../functions/timer_gettime.html"><i>timer_gettime</i>()</a>
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<a href="../functions/timer_settime.html"><i>timer_settime</i>()</a>
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<a href="../functions/sleep.html"><i>sleep</i>()</a>
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</pre>
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</blockquote>
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</blockquote>
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<h4><a name="tag_03_796_04"></a>RETURN VALUE</h4>
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<blockquote>
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<p>The <i>ualarm</i>() function shall return the number of microseconds remaining from the previous <i>ualarm</i>() call. If no
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timeouts are pending or if <i>ualarm</i>() has not previously been called, <i>ualarm</i>() shall return 0.</p>
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</blockquote>
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<h4><a name="tag_03_796_05"></a>ERRORS</h4>
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<blockquote>
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<p>No errors are defined.</p>
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</blockquote>
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<hr>
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<div class="box"><em>The following sections are informative.</em></div>
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<h4><a name="tag_03_796_06"></a>EXAMPLES</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_796_07"></a>APPLICATION USAGE</h4>
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<blockquote>
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<p>Applications are recommended to use <a href="../functions/nanosleep.html"><i>nanosleep</i>()</a> if the Timers option is
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supported, or <a href="../functions/setitimer.html"><i>setitimer</i>()</a>, <a href=
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"../functions/timer_create.html"><i>timer_create</i>()</a>, <a href="../functions/timer_delete.html"><i>timer_delete</i>()</a>, <a
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href="../functions/timer_getoverrun.html"><i>timer_getoverrun</i>()</a>, <a href=
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"../functions/timer_gettime.html"><i>timer_gettime</i>()</a>, or <a href=
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"../functions/timer_settime.html"><i>timer_settime</i>()</a> instead of this function.</p>
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</blockquote>
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<h4><a name="tag_03_796_08"></a>RATIONALE</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_796_09"></a>FUTURE DIRECTIONS</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_796_10"></a>SEE ALSO</h4>
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<blockquote>
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<p><a href="alarm.html"><i>alarm</i>()</a> , <a href="nanosleep.html"><i>nanosleep</i>()</a> , <a href=
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"setitimer.html"><i>setitimer</i>()</a> , <a href="sleep.html"><i>sleep</i>()</a> , <a href=
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"timer_create.html"><i>timer_create</i>()</a> , <a href="timer_delete.html"><i>timer_delete</i>()</a> , <a href=
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"timer_getoverrun.html"><i>timer_getoverrun</i>()</a> , the Base Definitions volume of IEEE Std 1003.1-2001, <a href=
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"../basedefs/unistd.h.html"><i><unistd.h></i></a></p>
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</blockquote>
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<h4><a name="tag_03_796_11"></a>CHANGE HISTORY</h4>
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<blockquote>
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<p>First released in Issue 4, Version 2.</p>
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</blockquote>
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<h4><a name="tag_03_796_12"></a>Issue 5</h4>
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<blockquote>
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<p>Moved from X/OPEN UNIX extension to BASE.</p>
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</blockquote>
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<h4><a name="tag_03_796_13"></a>Issue 6</h4>
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<blockquote>
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<p>This function is marked obsolescent.</p>
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</blockquote>
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<div class="box"><em>End of informative text.</em></div>
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UNIX ® is a registered Trademark of The Open Group.<br>
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POSIX ® is a registered Trademark of The IEEE.<br>
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