PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

PTHREAD_BARRIER_WAIT(3P)  POSIX Programmer's Manual PTHREAD_BARRIER_WAIT(3P)

PROLOG         top

       This manual page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior), or
       the interface may not be implemented on Linux.

NAME         top

       pthread_barrier_wait — synchronize at a barrier

SYNOPSIS         top

       #include <pthread.h>

       int pthread_barrier_wait(pthread_barrier_t *barrier);

DESCRIPTION         top

       The pthread_barrier_wait() function shall synchronize participating
       threads at the barrier referenced by barrier.  The calling thread
       shall block until the required number of threads have called
       pthread_barrier_wait() specifying the barrier.

       When the required number of threads have called
       pthread_barrier_wait() specifying the barrier, the constant
       PTHREAD_BARRIER_SERIAL_THREAD 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 pthread_barrier_init() function that
       referenced it.

       The constant PTHREAD_BARRIER_SERIAL_THREAD is defined in <pthread.h>
       and its value shall be distinct from any other value returned by
       pthread_barrier_wait().

       The results are undefined if this function is called with an
       uninitialized barrier.

       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.

       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.

RETURN VALUE         top

       Upon successful completion, the pthread_barrier_wait() function shall
       return PTHREAD_BARRIER_SERIAL_THREAD 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.

ERRORS         top

       This function shall not return an error code of [EINTR].

       The following sections are informative.

EXAMPLES         top

       None.

APPLICATION USAGE         top

       Applications using this function may be subject to priority
       inversion, as discussed in the Base Definitions volume of
       POSIX.1‐2008, Section 3.287, Priority Inversion.

RATIONALE         top

       If an implementation detects that the value specified by the barrier
       argument to pthread_barrier_wait() does not refer to an initialized
       barrier object, it is recommended that the function should fail and
       report an [EINVAL] error.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       pthread_barrier_destroy(3p)

       The Base Definitions volume of POSIX.1‐2008, Section 3.287, Priority
       Inversion, Section 4.11, Memory Synchronization, pthread.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information
       Technology -- 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 Standard 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_WAIT(3P)