mirror of https://github.com/mkerrisk/man-pages
133 lines
4.6 KiB
Plaintext
133 lines
4.6 KiB
Plaintext
.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
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.TH "PTHREAD_BARRIER_DESTROY" 3P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
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.\" pthread_barrier_destroy
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.SH NAME
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pthread_barrier_destroy, pthread_barrier_init \- destroy and initialize
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a barrier object (\fBADVANCED REALTIME
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THREADS\fP)
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.SH SYNOPSIS
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.LP
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\fB#include <pthread.h>
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.br
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.sp
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int pthread_barrier_destroy(pthread_barrier_t *\fP\fIbarrier\fP\fB);
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.br
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int pthread_barrier_init(pthread_barrier_t *restrict\fP \fIbarrier\fP\fB,
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.br
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\ \ \ \ \ \ const pthread_barrierattr_t *restrict\fP \fIattr\fP\fB,
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unsigned\fP \fIcount\fP\fB);
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\fP
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\fB
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.br
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\fP
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.SH DESCRIPTION
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.LP
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The \fIpthread_barrier_destroy\fP() function shall destroy the barrier
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referenced by \fIbarrier\fP and release any resources
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used by the barrier. The effect of subsequent use of the barrier is
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undefined until the barrier is reinitialized by another call to
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\fIpthread_barrier_init\fP(). An implementation may use this function
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to set \fIbarrier\fP to an invalid value. The results are
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undefined if \fIpthread_barrier_destroy\fP() is called when any thread
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is blocked on the barrier, or if this function is called
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with an uninitialized barrier.
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.LP
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The \fIpthread_barrier_init\fP() function shall allocate any resources
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required to use the barrier referenced by \fIbarrier\fP
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and shall initialize the barrier with attributes referenced by \fIattr\fP.
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If \fIattr\fP is NULL, the default barrier attributes
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shall be used; the effect is the same as passing the address of a
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default barrier attributes object. The results are undefined if
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\fIpthread_barrier_init\fP() is called when any thread is blocked
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on the barrier (that is, has not returned from the \fIpthread_barrier_wait\fP()
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call). The results are undefined if a barrier is used
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without first being initialized. The results are undefined if \fIpthread_barrier_init\fP()
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is called specifying an already
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initialized barrier.
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.LP
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The \fIcount\fP argument specifies the number of threads that must
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call \fIpthread_barrier_wait\fP() before any of them successfully
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return from the call.
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The value specified by \fIcount\fP must be greater than zero.
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.LP
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If the \fIpthread_barrier_init\fP() function fails, the barrier shall
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not be initialized and the contents of \fIbarrier\fP are
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undefined.
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.LP
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Only the object referenced by \fIbarrier\fP may be used for performing
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synchronization. The result of referring to copies of
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that object in calls to \fIpthread_barrier_destroy\fP() or \fIpthread_barrier_wait\fP()
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is undefined.
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.SH RETURN VALUE
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.LP
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Upon successful completion, these functions shall return zero; otherwise,
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an error number shall be returned to indicate the
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error.
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.SH ERRORS
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.LP
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The \fIpthread_barrier_destroy\fP() function may fail if:
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.TP 7
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.B EBUSY
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The implementation has detected an attempt to destroy a barrier while
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it is in use (for example, while being used in a \fIpthread_barrier_wait\fP()
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call) by another thread.
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.TP 7
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.B EINVAL
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The value specified by \fIbarrier\fP is invalid.
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.sp
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.LP
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The \fIpthread_barrier_init\fP() function shall fail if:
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.TP 7
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.B EAGAIN
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The system lacks the necessary resources to initialize another barrier.
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.TP 7
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.B EINVAL
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The value specified by \fIcount\fP is equal to zero.
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.TP 7
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.B ENOMEM
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Insufficient memory exists to initialize the barrier.
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.sp
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.LP
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The \fIpthread_barrier_init\fP() function may fail if:
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.TP 7
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.B EBUSY
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The implementation has detected an attempt to reinitialize a barrier
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while it is in use (for example, while being used in a \fIpthread_barrier_wait\fP()
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call) by another thread.
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.TP 7
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.B EINVAL
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The value specified by \fIattr\fP is invalid.
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.sp
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.LP
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These functions shall not return an error code of [EINTR].
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.LP
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\fIThe following sections are informative.\fP
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.SH EXAMPLES
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.LP
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None.
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.SH APPLICATION USAGE
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.LP
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The \fIpthread_barrier_destroy\fP() and \fIpthread_barrier_init\fP()
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functions are part of the Barriers option and need not be
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provided on all implementations.
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.SH RATIONALE
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.LP
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None.
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.SH FUTURE DIRECTIONS
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.LP
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None.
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.SH SEE ALSO
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.LP
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\fIpthread_barrier_wait\fP() , the Base Definitions volume of
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IEEE\ Std\ 1003.1-2001, \fI<pthread.h>\fP
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.SH COPYRIGHT
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Portions of this text are reprinted and reproduced in electronic form
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from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
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-- Portable Operating System Interface (POSIX), The Open Group Base
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Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
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Electrical and Electronics Engineers, Inc and The Open Group. In the
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event of any discrepancy between this version and the original IEEE and
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The Open Group Standard, the original IEEE and The Open Group Standard
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is the referee document. The original Standard can be obtained online at
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http://www.opengroup.org/unix/online.html .
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