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161 lines
6.6 KiB
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<HTML>
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<HEAD>
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<META HTTP-EQUIV="CONTENT-TYPE" CONTENT="text/html; charset=utf-8">
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<TITLE>"PTHREAD_BARRIER_WAIT"(P) manual page</TITLE>
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<META NAME="GENERATOR" CONTENT="OpenOffice.org 2.0 (Linux)">
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<META NAME="CREATED" CONTENT="20050504;11484200">
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<META NAME="CHANGEDBY" CONTENT="Ross Johnson">
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<META NAME="CHANGED" CONTENT="20060408;9504600">
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<!-- manual page source format generated by PolyglotMan v3.2, -->
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<!-- available at http://polyglotman.sourceforge.net/ -->
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</HEAD>
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<BODY LANG="en-GB" BGCOLOR="#ffffff" DIR="LTR">
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<H4>POSIX Threads for Windows – REFERENCE - <A HREF="http://sources.redhat.com/pthreads-win32">Pthreads-w32</A></H4>
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<P><A HREF="index.html">Reference Index</A></P>
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<P><A HREF="#toc">Table of Contents</A></P>
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<H2><A HREF="#toc0" NAME="sect0">Name</A></H2>
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<P>pthread_barrier_wait - synchronize at a barrier (<B>ADVANCED
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REALTIME THREADS</B>)
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</P>
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<H2><A HREF="#toc1" NAME="sect1">Synopsis</A></H2>
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<P><B>#include <pthread.h> </B>
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</P>
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<P><B>int pthread_barrier_wait(pthread_barrier_t *</B><I>barrier</I><B>);
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</B>
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</P>
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<H2><A HREF="#toc2" NAME="sect2">Description</A></H2>
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<P>The <B>pthread_barrier_wait</B> function shall synchronize
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participating threads at the barrier referenced by <I>barrier</I>.
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The calling thread shall block until the required number of threads
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have called <B>pthread_barrier_wait</B> specifying the barrier.
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</P>
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<P>When the required number of threads have called
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<B>pthread_barrier_wait</B> specifying the barrier, the constant
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<B>PTHREAD_BARRIER_SERIAL_THREAD</B> shall be returned to one
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unspecified thread and zero shall be returned to each of the
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remaining threads. At this point, the barrier shall be reset to the
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state it had as a result of the most recent <A HREF="pthread_barrier_init.html"><B>pthread_barrier_init</B>(3)</A>
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function that referenced it.
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</P>
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<P>The constant <B>PTHREAD_BARRIER_SERIAL_THREAD</B> is defined in
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<I><pthread.h></I> and its value shall be distinct from any
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other value returned by <B>pthread_barrier_wait</B> .
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</P>
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<P>The results are undefined if this function is called with an
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uninitialized barrier.
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</P>
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<P>If a signal is delivered to a thread blocked on a barrier, upon
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return from the signal handler the thread shall resume waiting at the
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barrier if the barrier wait has not completed (that is, if the
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required number of threads have not arrived at the barrier during the
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execution of the signal handler); otherwise, the thread shall
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continue as normal from the completed barrier wait. Until the thread
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in the signal handler returns from it, it is unspecified whether
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other threads may proceed past the barrier once they have all reached
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it.
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</P>
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<P>A thread that has blocked on a barrier shall not prevent any
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unblocked thread that is eligible to use the same processing
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resources from eventually making forward progress in its execution.
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Eligibility for processing resources shall be determined by the
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scheduling policy.
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</P>
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<H2><A HREF="#toc3" NAME="sect3">Return Value</A></H2>
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<P>Upon successful completion, the <B>pthread_barrier_wait</B>
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function shall return <B>PTHREAD_BARRIER_SERIAL_THREAD</B> for a
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single (arbitrary) thread synchronized at the barrier and zero for
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each of the other threads. Otherwise, an error number shall be
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returned to indicate the error.
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</P>
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<H2><A HREF="#toc4" NAME="sect4">Errors</A></H2>
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<P>The <B>pthread_barrier_wait</B> function may fail if:
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</P>
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<DL>
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<DT><B>EINVAL</B>
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</DT><DD STYLE="margin-bottom: 0.5cm">
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The value specified by <I>barrier</I> does not refer to an
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initialized barrier object.
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</DD></DL>
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<P>
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This function shall not return an error code of [EINTR].
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</P>
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<P><I>The following sections are informative.</I>
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</P>
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<H2><A HREF="#toc5" NAME="sect5">Examples</A></H2>
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<P>None.
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</P>
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<H2><A HREF="#toc6" NAME="sect6">Application Usage</A></H2>
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<P>Applications using this function may be subject to priority
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inversion, as discussed in the Base Definitions volume of
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IEEE Std 1003.1-2001, Section 3.285, Priority Inversion.
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</P>
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<P>The <B>pthread_barrier_wait</B> function is part of the Barriers
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option and need not be provided on all implementations.
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</P>
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<P><B>Pthreads-w32</B> defines <B>_POSIX_BARRIERS</B> to indicate
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that this routine is implemented and may be used.</P>
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<H2><A HREF="#toc7" NAME="sect7">Rationale</A></H2>
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<P>None.
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</P>
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<H2><A HREF="#toc8" NAME="sect8">Future Directions</A></H2>
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<P>None.
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</P>
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<H2><A HREF="#toc11" NAME="sect11">Known Bugs</A></H2>
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<DL>
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None.</DL>
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<H2>
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<A HREF="#toc9" NAME="sect9">See Also</A></H2>
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<P><A HREF="pthread_barrier_init.html"><B>pthread_barrier_destroy</B>(3)</A>,
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<A HREF="pthread_barrier_init.html"><B>pthread_barrier_init(3)</B></A>,
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the Base Definitions volume of IEEE Std 1003.1-2001,
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<I><pthread.h></I>
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</P>
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<H2><A HREF="#toc10" NAME="sect10">Copyright</A></H2>
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<P>Portions of this text are reprinted and reproduced in electronic
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form from IEEE Std 1003.1, 2003 Edition, Standard for Information
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Technology -- Portable Operating System Interface (POSIX), The Open
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Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the
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Institute of Electrical and Electronics Engineers, Inc and The Open
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Group. In the event of any discrepancy between this version and the
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original IEEE and The Open Group Standard, the original IEEE and The
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Open Group Standard is the referee document. The original Standard
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can be obtained online at <A HREF="http://www.opengroup.org/unix/online.html">http://www.opengroup.org/unix/online.html</A>
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.
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</P>
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<P>Modified by Ross Johnson for use with <A HREF="http://sources.redhat.com/pthreads-win32">Pthreads-w32</A>.</P>
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<HR>
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<P><A NAME="toc"></A><B>Table of Contents</B></P>
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<UL>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect0" NAME="toc0">Name</A>
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</P>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect1" NAME="toc1">Synopsis</A>
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</P>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect2" NAME="toc2">Description</A>
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</P>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect3" NAME="toc3">Return
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Value</A>
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</P>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect4" NAME="toc4">Errors</A>
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</P>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect5" NAME="toc5">Examples</A>
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</P>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect6" NAME="toc6">Application
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Usage</A>
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</P>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect7" NAME="toc7">Rationale</A>
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</P>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect8" NAME="toc8">Future
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Directions</A>
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</P>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect11" NAME="toc11">Known
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Bugs</A>
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</P>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect9" NAME="toc9">See
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Also</A>
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</P>
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<LI><P><A HREF="#sect10" NAME="toc10">Copyright</A>
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</P>
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</UL>
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</BODY>
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</HTML>
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