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PTHREAD_RWLOCK_TIM... DragonFly Library Functions Manual PTHREAD_RWLOCK_TIM...
pthread_rwlock_timedrdlock -- acquire a read-write lock for reading or
give up after a specified period
POSIX Threads Library (libpthread, -lpthread)
pthread_rwlock_timedrdlock(pthread_rwlock_t * restrict rwlock,
const struct timespec * restrict abs_timeout);
This function acquires a read lock on the read-write lock rwlock.
However, if the lock cannot be acquired without waiting for another
thread to unlock the lock, this wait shall be terminated when abs_timeout
A thread may hold multiple concurrent read locks. The
pthread_rwlock_unlock(3) function must be called once for each lock
If the thread should be interrupted by a signal, the
pthread_rwlock_timedrdlock() function will be automatically restarted
after the thread returns from the signal handler.
The calling thread may deadlock if at the time the call is made it holds
a write lock on rwlock. The results are undefined if this function is
called with an uninitialized read-write lock.
To prevent writer starvation, writers are favored over readers.
If successful, the pthread_rwlock_timedrdlock() function will return
zero. Otherwise, an error number will be returned to indicate the error.
This function shall not return an error code of EINTR.
The pthread_rwlock_timedrdlock() function will fail if:
[ETIMEDOUT] The lock could not be acquired before the specified
The pthread_rwlock_timedrdlock() function may fail if:
[EAGAIN] The read lock could not be acquired because the
maximum number of read locks for rwlock would be
[EDEADLK] The calling thread already holds a write lock on
[EINVAL] The value specified by rwlock does not refer to an
initialized read-write lock object, or the abs_timeout
nanosecond value is less than zero or greater than or
equal to 1 billion.
The pthread_rwlock_timedrdlock() function is expected to conform to
ISO/IEC 9945-1:1996 (``POSIX.1'').
The pthread_rwlock_timedrdlock() function first appeared in FreeBSD 5.2.
DragonFly 5.1 February 22, 2018 DragonFly 5.1