PTHREAD_BARRIER_DESTROY(3P) POSIX Programmer's Manual PTHREAD_BARRIER_DESTROY(3P)
PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond-
ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.
NAME
pthread_barrier_destroy, pthread_barrier_init -- destroy and initialize a barrier object
SYNOPSIS
#include <pthread.h>
int pthread_barrier_destroy(pthread_barrier_t *barrier);
int pthread_barrier_init(pthread_barrier_t *restrict barrier,
const pthread_barrierattr_t *restrict attr, unsigned count);
DESCRIPTION
The pthread_barrier_destroy() function shall destroy the barrier referenced by barrier 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 pthread_barrier_init(). An
implementation may use this function to set barrier to an invalid value. The results are undefined if pthread_barrier_destroy() is called
when any thread is blocked on the barrier, or if this function is called with an uninitialized barrier.
The pthread_barrier_init() function shall allocate any resources required to use the barrier referenced by barrier and shall initialize the
barrier with attributes referenced by attr. If attr is NULL, the default barrier attributes shall be used; the effect is the same as pass-
ing the address of a default barrier attributes object. The results are undefined if pthread_barrier_init() is called when any thread is
blocked on the barrier (that is, has not returned from the pthread_barrier_wait() call). The results are undefined if a barrier is used
without first being initialized. The results are undefined if pthread_barrier_init() is called specifying an already initialized barrier.
The count argument specifies the number of threads that must call pthread_barrier_wait() before any of them successfully return from the
call. The value specified by count must be greater than zero.
If the pthread_barrier_init() function fails, the barrier shall not be initialized and the contents of barrier are undefined.
Only the object referenced by barrier may be used for performing synchronization. The result of referring to copies of that object in calls
to pthread_barrier_destroy() or pthread_barrier_wait() is undefined.
RETURN VALUE
Upon successful completion, these functions shall return zero; otherwise, an error number shall be returned to indicate the error.
ERRORS
The pthread_barrier_init() function shall fail if:
EAGAIN The system lacks the necessary resources to initialize another barrier.
EINVAL The value specified by count is equal to zero.
ENOMEM Insufficient memory exists to initialize the barrier.
These functions shall not return an error code of [EINTR].
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
If an implementation detects that the value specified by the barrier argument to pthread_barrier_destroy() does not refer to an initialized
barrier object, it is recommended that the function should fail and report an [EINVAL] error.
If an implementation detects that the value specified by the attr argument to pthread_barrier_init() does not refer to an initialized bar-
rier attributes object, it is recommended that the function should fail and report an [EINVAL] error.
If an implementation detects that the value specified by the barrier argument to pthread_barrier_destroy() or pthread_barrier_init() refers
to a barrier that is in use (for example, in a pthread_barrier_wait() call) by another thread, or detects that the value specified by the
barrier argument to pthread_barrier_init() refers to an already initialized barrier object, it is recommended that the function should fail
and report an [EBUSY] error.
FUTURE DIRECTIONS
None.
SEE ALSO
pthread_barrier_wait()
The Base Definitions volume of POSIX.1-2008, <pthread.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition, Standard for Information Technol-
ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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 Stan-
dard is the referee document. The original Standard can be obtained online at http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source
files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE
/The Open Group 2013 PTHREAD_BARRIER_DESTROY(3P)