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PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
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PTHREAD_...RYWRLOCK(3P) POSIX Programmer's Manual PTHREAD_...RYWRLOCK(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_trywrlock, pthread_rwlock_wrlock — lock a read-
write lock object for writing
#include <pthread.h>
int pthread_rwlock_trywrlock(pthread_rwlock_t *rwlock);
int pthread_rwlock_wrlock(pthread_rwlock_t *rwlock);
The pthread_rwlock_trywrlock() function shall apply a write lock
like the pthread_rwlock_wrlock() function, with the exception that
the function shall fail if any thread currently holds rwlock (for
reading or writing).
The pthread_rwlock_wrlock() function shall apply a write lock to
the read-write lock referenced by rwlock. The calling thread
shall acquire the write lock if no thread (reader or writer) holds
the read-write lock rwlock. Otherwise, if another thread holds
the read-write lock rwlock, the calling thread shall block until
it can acquire the lock. If a deadlock condition occurs or the
calling thread already owns the read-write lock for writing or
reading, the call shall either deadlock or return [EDEADLK].
Results are undefined if any of these functions are called with an
uninitialized read-write lock.
If a signal is delivered to a thread waiting for a read-write lock
for writing, upon return from the signal handler the thread
resumes waiting for the read-write lock for writing as if it was
not interrupted.
The pthread_rwlock_trywrlock() function shall return zero if the
lock for writing on the read-write lock object referenced by
rwlock is acquired. Otherwise, an error number shall be returned
to indicate the error.
If successful, the pthread_rwlock_wrlock() function shall return
zero; otherwise, an error number shall be returned to indicate the
error.
The pthread_rwlock_trywrlock() function shall fail if:
EBUSY The read-write lock could not be acquired for writing
because it was already locked for reading or writing.
The pthread_rwlock_wrlock() function may fail if:
EDEADLK
A deadlock condition was detected or the current thread
already owns the read-write lock for writing or reading.
These functions shall not return an error code of [EINTR].
The following sections are informative.
None.
Applications using these functions may be subject to priority
inversion, as discussed in the Base Definitions volume of
POSIX.1‐2017, Section 3.291, Priority Inversion.
If an implementation detects that the value specified by the
rwlock argument to pthread_rwlock_trywrlock() or
pthread_rwlock_wrlock() does not refer to an initialized read-
write lock object, it is recommended that the function should fail
and report an [EINVAL] error.
None.
pthread_rwlock_destroy(3p), pthread_rwlock_rdlock(3p),
pthread_rwlock_timedrdlock(3p), pthread_rwlock_timedwrlock(3p),
pthread_rwlock_unlock(3p)
The Base Definitions volume of POSIX.1‐2017, Section 3.291,
Priority Inversion, Section 4.12, Memory Synchronization,
pthread.h(0p)
Portions of this text are reprinted and reproduced in electronic
form from IEEE Std 1003.1-2017, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The
Open Group Base Specifications Issue 7, 2018 Edition, Copyright
(C) 2018 by the Institute of Electrical and Electronics Engineers,
Inc and The Open Group. 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.opengroup.org/unix/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 2017 PTHREAD_...RYWRLOCK(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_unlock(3p), pthread_rwlock_wrlock(3p)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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