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PTHREAD_RWLOCK_WRLO... FreeBSD Library Functions Manual	PTHREAD_RWLOCK_WRLO...

NAME
     pthread_rwlock_wrlock, pthread_rwlock_trywrlock --	acquire	a read/write
     lock for writing

LIBRARY
     Reentrant C Library (libc_r, -lc_r)

SYNOPSIS
     #include <pthread.h>

     int
     pthread_rwlock_wrlock(pthread_rwlock_t *lock);

     int
     pthread_rwlock_trywrlock(pthread_rwlock_t *lock);

DESCRIPTION
     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
     obtained.

     The results are undefined if the calling thread already holds the lock at
     the time the call is made.

IMPLEMENTATION NOTES
     To	prevent	writer starvation, writers are favored over readers.

RETURN VALUES
     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.

SEE ALSO
     pthread_rwlock_init(3), pthread_rwlock_rdlock(3),
     pthread_rwlock_tryrdlock(3), pthread_rwlock_unlock(3)

STANDARDS
     The pthread_rwlock_wrlock() and pthread_rwlock_trywrlock()	functions are
     expected to conform to Version 2 of the Single UNIX Specification
     (``SUSv2'').

ERRORS
     The pthread_rwlock_trywrlock() function will fail if:

     [EBUSY]		The calling thread is not able to acquire the lock
			without	blocking.

     The pthread_rwlock_wrlock() and pthread_rwlock_trywrlock()	functions may
     fail if:

     [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).

HISTORY
     The pthread_rwlock_wrlock() function first	appeared in FreeBSD 3.0.

FreeBSD	10.1			August 4, 1998			  FreeBSD 10.1

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | IMPLEMENTATION NOTES | RETURN VALUES | SEE ALSO | STANDARDS | ERRORS | HISTORY

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