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

PTHREAD_RWLOCK_UNLOCK(3P) POSIX Programmer's ManualPTHREAD_RWLOCK_UNLOCK(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_rwlock_unlock — unlock a read-write lock object

SYNOPSIS         top

       #include <pthread.h>

       int pthread_rwlock_unlock(pthread_rwlock_t *rwlock);

DESCRIPTION         top

       The pthread_rwlock_unlock() function shall release a lock held on the
       read-write lock object referenced by rwlock.  Results are undefined
       if the read-write lock rwlock is not held by the calling thread.

       If this function is called to release a read lock from the read-write
       lock object and there are other read locks currently held on this
       read-write lock object, the read-write lock object remains in the
       read locked state. If this function releases the last read lock for
       this read-write lock object, the read-write lock object shall be put
       in the unlocked state with no owners.

       If this function is called to release a write lock for this read-
       write lock object, the read-write lock object shall be put in the
       unlocked state.

       If there are threads blocked on the lock when it becomes available,
       the scheduling policy shall determine which thread(s) shall acquire
       the lock.  If the Thread Execution Scheduling option is supported,
       when threads executing with the scheduling policies SCHED_FIFO,
       SCHED_RR, or SCHED_SPORADIC are waiting on the lock, they shall
       acquire the lock in priority order when the lock becomes available.
       For equal priority threads, write locks shall take precedence over
       read locks.  If the Thread Execution Scheduling option is not
       supported, it is implementation-defined whether write locks take
       precedence over read locks.

       Results are undefined if this function is called with an
       uninitialized read-write lock.

RETURN VALUE         top

       If successful, the pthread_rwlock_unlock() function shall return
       zero; otherwise, an error number shall be returned to indicate the
       error.

ERRORS         top

       The pthread_rwlock_unlock() function shall not return an error code
       of [EINTR].

       The following sections are informative.

EXAMPLES         top

       None.

APPLICATION USAGE         top

       None.

RATIONALE         top

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

       If an implementation detects that the value specified by the rwlock
       argument to pthread_rwlock_unlock() refers to a read-write lock
       object for which the current thread does not hold a lock, it is
       recommended that the function should fail and report an [EPERM]
       error.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       pthread_rwlock_destroy(3p), pthread_rwlock_rdlock(3p),
       pthread_rwlock_timedrdlock(3p), pthread_rwlock_timedwrlock(3p),
       pthread_rwlock_trywrlock(3p)

       The  Base  Definitions  volume  of POSIX.1‐2008, 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_RWLOCK_UNLOCK(3P)

Pages that refer to this page: pthread.h(0p)pthread_rwlock_destroy(3p)pthread_rwlock_rdlock(3p)pthread_rwlock_timedrdlock(3p)pthread_rwlock_timedwrlock(3p)pthread_rwlock_trywrlock(3p)