<!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_DESTROY"(P) manual page</TITLE> <META NAME="GENERATOR" CONTENT="OpenOffice.org 1.1.3 (Linux)"> <META NAME="CREATED" CONTENT="20050504;11372800"> <META NAME="CHANGED" CONTENT="20050505;18164500"> <!-- 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_destroy, pthread_barrier_init - destroy and initialize a barrier object (<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_destroy(pthread_barrier_t *</B><I>barrier</I><B>); <BR>int pthread_barrier_init(pthread_barrier_t *restrict</B> <I>barrier</I><B>, const pthread_barrierattr_t *restrict</B> <I>attr</I><B>, unsigned</B> <I>count</I><B>); </B> </P> <H2><A HREF="#toc2" NAME="sect2">Description</A></H2> <P>The <B>pthread_barrier_destroy</B> function shall destroy the barrier referenced by <I>barrier</I> and release any resources used by the barrier. The effect of subsequent use of the barrier is undefined until the barrier is reinitialized by another call to <B>pthread_barrier_init</B> . An implementation may use this function to set <I>barrier</I> to an invalid value. The results are undefined if <B>pthread_barrier_destroy</B> is called when any thread is blocked on the barrier, or if this function is called with an uninitialized barrier. </P> <P>The <B>pthread_barrier_init</B> function shall allocate any resources required to use the barrier referenced by <I>barrier</I> and shall initialize the barrier with attributes referenced by <I>attr</I>. If <I>attr</I> is NULL, the default barrier attributes shall be used; the effect is the same as passing the address of a default barrier attributes object. The results are undefined if <B>pthread_barrier_init</B> is called when any thread is blocked on the barrier (that is, has not returned from the <A HREF="pthread_barrier_wait.html"><B>pthread_barrier_wait</B>(3)</A> call). The results are undefined if a barrier is used without first being initialized. The results are undefined if <B>pthread_barrier_init</B> is called specifying an already initialized barrier. </P> <P>The <I>count</I> argument specifies the number of threads that must call <A HREF="pthread_barrier_wait.html"><B>pthread_barrier_wait</B>(3)</A> before any of them successfully return from the call. The value specified by <I>count</I> must be greater than zero. </P> <P>If the <B>pthread_barrier_init</B> function fails, the barrier shall not be initialized and the contents of <I>barrier</I> are undefined. </P> <P>Only the object referenced by <I>barrier</I> may be used for performing synchronization. The result of referring to copies of that object in calls to <B>pthread_barrier_destroy</B> <B>or</B> <A HREF="pthread_barrier_wait.html"><B>pthread_barrier_wait</B>(3)</A> is undefined.</P> <H2><A HREF="#toc3" NAME="sect3">Return Value</A></H2> <P>Upon successful completion, these functions shall return zero; 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_destroy</B><SPAN STYLE="font-weight: medium"> function may fail if:</SPAN> </P> <DL> <DT><B>EBUSY</B> </DT><DD> The implementation has detected an attempt to destroy a barrier while it is in use (for example, while being used in a <A HREF="pthread_barrier_wait.html"><B>pthread_barrier_wait</B>(3)</A> call) by another thread. </DD><DT> <B>EINVAL</B> </DT><DD STYLE="margin-bottom: 0.5cm"> The value specified by <I>barrier</I> is invalid. </DD></DL> <P> The <B>pthread_barrier_init</B> function shall fail if: </P> <DL> <DT><B>EAGAIN</B> </DT><DD> The system lacks the necessary resources to initialize another barrier. </DD><DT> <B>EINVAL</B> </DT><DD> The value specified by <I>count</I> is equal to zero. </DD><DT> <B>ENOMEM</B> </DT><DD STYLE="margin-bottom: 0.5cm"> Insufficient memory exists to initialize the barrier. </DD></DL> <P> The <B>pthread_barrier_init</B> function may fail if: </P> <DL> <DT><B>EBUSY</B> </DT><DD> The implementation has detected an attempt to reinitialize a barrier while it is in use (for example, while being used in a <A HREF="pthread_barrier_wait.html"><B>pthread_barrier_wait</B>(3)</A> call) by another thread. </DD><DT> <B>EINVAL</B> </DT><DD STYLE="margin-bottom: 0.5cm"> The value specified by <I>attr</I> is invalid. </DD></DL> <P> These functions 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>The <B>pthread_barrier_destroy</B> and <B>pthread_barrier_init</B> functions are 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 these routines are 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="#toc9" NAME="sect9">See Also</A></H2> <P><A HREF="pthread_barrier_wait.html"><B>pthread_barrier_wait</B>(3)</A> <B>,</B> 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="#sect9" NAME="toc9">See Also</A> </P> <LI><P><A HREF="#sect10" NAME="toc10">Copyright</A> </P> </UL> </BODY> </HTML>