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