📄 pthread_barrier_wait.html
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta name="generator" content="HTML Tidy, see www.w3.org"><meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><link type="text/css" rel="stylesheet" href="style.css"><!-- Generated by The Open Group's rhtm tool v1.2.1 --><!-- Copyright (c) 2001-2003 The Open Group, All Rights Reserved --><title>pthread_barrier_wait</title></head><body bgcolor="white"><script type="text/javascript" language="JavaScript" src="../jscript/codes.js"></script><basefont size="3"> <a name="pthread_barrier_wait"></a> <a name="tag_03_508"></a><!-- pthread_barrier_wait --> <!--header start--><center><font size="2">The Open Group Base Specifications Issue 6<br>IEEE Std 1003.1, 2003 Edition<br>Copyright © 2001-2003 The IEEE and The Open Group, All Rights reserved.</font></center><!--header end--><hr size="2" noshade><h4><a name="tag_03_508_01"></a>NAME</h4><blockquote>pthread_barrier_wait - synchronize at a barrier (<b>ADVANCED REALTIME THREADS</b>)</blockquote><h4><a name="tag_03_508_02"></a>SYNOPSIS</h4><blockquote class="synopsis"><div class="box"><code><tt><sup>[<a href="javascript:open_code('THR BAR')">THR BAR</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> #include <<a href="../basedefs/pthread.h.html">pthread.h</a>><br><br> int pthread_barrier_wait(pthread_barrier_t *</tt><i>barrier</i><tt>); <img src="../images/opt-end.gif" alt="[Option End]" border="0"></tt></code></div><tt><br></tt></blockquote><h4><a name="tag_03_508_03"></a>DESCRIPTION</h4><blockquote><p>The <i>pthread_barrier_wait</i>() function shall synchronize participating threads at the barrier referenced by <i>barrier</i>.The calling thread shall block until the required number of threads have called <i>pthread_barrier_wait</i>() specifying thebarrier.</p><p>When the required number of threads have called <i>pthread_barrier_wait</i>() specifying the barrier, the constantPTHREAD_BARRIER_SERIAL_THREAD shall be returned to one unspecified thread and zero shall be returned to each of the remainingthreads. At this point, the barrier shall be reset to the state it had as a result of the most recent <a href="../functions/pthread_barrier_init.html"><i>pthread_barrier_init</i>()</a> function that referenced it.</p><p>The constant PTHREAD_BARRIER_SERIAL_THREAD is defined in <a href="../basedefs/pthread.h.html"><i><pthread.h></i></a> andits value shall be distinct from any other value returned by <i>pthread_barrier_wait</i>().</p><p>The results are undefined if this function is called with an uninitialized barrier.</p><p>If a signal is delivered to a thread blocked on a barrier, upon return from the signal handler the thread shall resume waitingat the barrier if the barrier wait has not completed (that is, if the required number of threads have not arrived at the barrierduring the execution of the signal handler); otherwise, the thread shall continue as normal from the completed barrier wait. Untilthe thread in the signal handler returns from it, it is unspecified whether other threads may proceed past the barrier once theyhave all reached it.</p><p>A thread that has blocked on a barrier shall not prevent any unblocked thread that is eligible to use the same processingresources from eventually making forward progress in its execution. Eligibility for processing resources shall be determined by thescheduling policy.</p></blockquote><h4><a name="tag_03_508_04"></a>RETURN VALUE</h4><blockquote><p>Upon successful completion, the <i>pthread_barrier_wait</i>() function shall return PTHREAD_BARRIER_SERIAL_THREAD for a single(arbitrary) thread synchronized at the barrier and zero for each of the other threads. Otherwise, an error number shall be returnedto indicate the error.</p></blockquote><h4><a name="tag_03_508_05"></a>ERRORS</h4><blockquote><p>The <i>pthread_barrier_wait</i>() function may fail if:</p><dl compact><dt>[EINVAL]</dt><dd>The value specified by <i>barrier</i> does not refer to an initialized barrier object.</dd></dl><p>This function shall not return an error code of [EINTR].</p></blockquote><hr><div class="box"><em>The following sections are informative.</em></div><h4><a name="tag_03_508_06"></a>EXAMPLES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_508_07"></a>APPLICATION USAGE</h4><blockquote><p>Applications using this function may be subject to priority inversion, as discussed in the Base Definitions volume ofIEEE Std 1003.1-2001, <a href="../basedefs/xbd_chap03.html#tag_03_285">Section 3.285, Priority Inversion</a>.</p><p>The <i>pthread_barrier_wait</i>() function is part of the Barriers option and need not be provided on all implementations.</p></blockquote><h4><a name="tag_03_508_08"></a>RATIONALE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_508_09"></a>FUTURE DIRECTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_508_10"></a>SEE ALSO</h4><blockquote><p><a href="pthread_barrier_destroy.html"><i>pthread_barrier_destroy</i>()</a> , the Base Definitions volume ofIEEE Std 1003.1-2001, <a href="../basedefs/pthread.h.html"><i><pthread.h></i></a></p></blockquote><h4><a name="tag_03_508_11"></a>CHANGE HISTORY</h4><blockquote><p>First released in Issue 6. Derived from IEEE Std 1003.1j-2000.</p><p>In the SYNOPSIS, the inclusion of <a href="../basedefs/sys/types.h.html"><i><sys/types.h></i></a> is no longerrequired.</p></blockquote><div class="box"><em>End of informative text.</em></div><hr><hr size="2" noshade><center><font size="2"><!--footer start-->UNIX ® is a registered Trademark of The Open Group.<br>POSIX ® is a registered Trademark of The IEEE.<br>[ <a href="../mindex.html">Main Index</a> | <a href="../basedefs/contents.html">XBD</a> | <a href="../utilities/contents.html">XCU</a> | <a href="../functions/contents.html">XSH</a> | <a href="../xrat/contents.html">XRAT</a>]</font></center><!--footer end--><hr size="2" noshade></body></html>⌨️ 快捷键说明
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