|
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)
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.
pthread_rwlock_unlock — unlock a read-write lock object
#include <pthread.h>
int pthread_rwlock_unlock(pthread_rwlock_t *rwlock);
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.
If successful, the pthread_rwlock_unlock() function shall return
zero; otherwise, an error number shall be returned to indicate the
error.
The pthread_rwlock_unlock() function shall not return an error code
of [EINTR].
The following sections are informative.
None.
None.
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.
None.
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)
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)