tis_write_trylock(3) [osf1 man page]

tis_write_trylock(3)					     Library Functions Manual					      tis_write_trylock(3)

NAME

       tis_write_trylock - Attempts to acquire the specified read-write lock for write access.

LIBRARY

       Standard C Library (libc.so, libc.a)

SYNOPSIS

       #include <tis.h>

       int   tis_write_trylock(
			      tis_rwlock_t   *lock);

STANDARDS

       None

PARAMETERS

       Address of the read-write lock to be acquired for write access.

DESCRIPTION

       This routine attempts to acquire a read-write lock for write access.  The routine attempts to immediately acquire the lock.  If the lock is
       acquired, zero (0) is returned.	If the lock is held by another thread (for either read or write access), [EBUSY] is returned and the call-
       ing thread does not wait for the write-access lock to be acquired.

       Note that it is a coding error to attempt to acquire the lock for write access if the lock is already held by the calling thread. (However,
       this routine returns [EBUSY] anyway, because no ownership error-checking takes place.)

RETURN VALUES

       If an error condition occurs, this routine returns an integer value indicating the type of error.  Possible return values are  as  follows:
       Successful completion; the lock is acquired for write access.  The lock was not acquired for write access, as it is already held by another
       thread.

ERRORS

       None

RELATED INFORMATION

       Functions:  tis_read_lock(3),  tis_read_trylock(3),  tis_read_unlock(3),  tis_rwlock_destroy(3),   tis_rwlock_init(3),	tis_write_lock(3),
       tis_write_unlock(3)

       Manuals: Guide to DECthreads and Programmer's Guide delim off

															      tis_write_trylock(3)

pthread_rwlock_unlock(3)				     Library Functions Manual					  pthread_rwlock_unlock(3)

NAME

       pthread_rwlock_unlock - Unlock a read-write lock.

LIBRARY

       DECthreads POSIX 1003.1c Library (libpthread.so)

SYNOPSIS

       #include <pthread.h>

       int   pthread_rwlock_unlock(
			     pthread_rwlock_t	      *rwlock);

PARAMETERS

       Address of the read-write lock to be unlocked.

DESCRIPTION

       This  routine  releases a lock acquisition held on the read-write lock object referenced by rwlock.  Results are undefined if rwlock is not
       held by the calling thread.

       If this routine is called to release a lock for read access on rwlock and the calling thread also currently  holds  other  locks  for  read
       access on rwlock, the read-write lock object remains in the read locked state.  If this routine releases the calling thread's last lock for
       read access on rwlock, the calling thread is not longer one of the owners of the lock object.

       If this routine is called to release a lock for write access on rwlock, the lock object is put in the unlocked state with no owners.

       If a call to this routine results in the read-write lock object becoming unlocked and there are multiple thread	waiting  to  acquire  that
       lock  for  write  access,  DECthreads  uses the scheduling policy of those waiting threads to determine which thread next acquires the lock
       object for write access. If there are multiple thread waiting to acquire the read-write lock object for read access,  DECthreads  uses  the
       scheduling  policy  of  those waiting threads to determine the order in which those threads acquire the lock for read access.  If there are
       multiple threads waiting to acquire the read-write lock object for both read and write access, it is unspecified whether a  thread  waiting
       for read access or for write access next acquires the lock object.

       If the read-write lock object referenced by rwlock is not initialized, the results of calling this routine are undefined.

RETURN VALUES

       If  an  error condition occurs, this routine returns an integer value indicating the type of error.  Possible return values are as follows:
       Successful completion.  The values specified by rwlock does not refer to an initialized read-write lock object.	The  current  thread  does
       not hold the read-write lock object.

ERRORS

       None

RELATED INFORMATION

       Functions: pthread_rwlock_init(3), pthread_rwlock_rdlock(3), pthread_rwlock_wrlock(3), pthread_rwlockattr_init(3)

       Manuals: Guide to DECthreads and Programmer's Guide

       delim off

															  pthread_rwlock_unlock(3)