DragonFly On-Line Manual Pages
PTHREAD_RWLOCK_WRLOCK(3) DragonFly Library Functions Manual
pthread_rwlock_wrlock, pthread_rwlock_trywrlock - acquire a read/write
lock for writing
POSIX Threads Library (libpthread, -lpthread)
The pthread_rwlock_wrlock() function blocks until a write lock can be
acquired against lock. The pthread_rwlock_trywrlock() function performs
the same action, but does not block if the lock cannot be immediately
The results are undefined if the calling thread already holds the lock at
the time the call is made.
To prevent writer starvation, writers are favored over readers.
If successful, the pthread_rwlock_wrlock() and pthread_rwlock_trywrlock()
functions will return zero. Otherwise an error number will be returned
to indicate the error.
The pthread_rwlock_trywrlock() function will fail if:
[EBUSY] The calling thread is not able to acquire the lock
The pthread_rwlock_wrlock() and pthread_rwlock_trywrlock() functions may
[EDEADLK] The calling thread already owns the read/write lock
(for reading or writing).
[EINVAL] The value specified by lock is invalid.
[ENOMEM] Insufficient memory exists to initialize the lock
(applies to statically initialized locks only).
The pthread_rwlock_wrlock() and pthread_rwlock_trywrlock() functions are
expected to conform to Version 2 of the Single UNIX Specification
The pthread_rwlock_wrlock() function first appeared in FreeBSD 3.0.
DragonFly 5.9-DEVELOPMENT July 10, 2009 DragonFly 5.9-DEVELOPMENT