rw_trywrlock(3synch)
rw_trywrlock --
conditionally acquire a reader-writer lock in write mode
Synopsis
cc [options] -Kthread file
#include <synch.h>
int rw_trywrlock(rwlock_t *lock);
Description
rw_trywrlock makes a single attempt to acquire the
reader-writer lock pointed to by lock in write mode;
it does not block the caller
if the lock is unavailable.
A reader-writer lock can be held by any number of readers
at one time,
but only one writer at a time can hold the lock.
If the lock is free,
rw_trywrlock acquires the lock in write mode
and the caller proceeds.
If the lock is currently held,
rw_trywrlock immediately returns EBUSY to the caller,
without acquiring the lock.
lock must previously have been initialized
(see rwlock_init).
Usage
rw_trywrlock is used when the caller does not want to block
if the lock is unavailable.
Return values
rw_trywrlock returns zero for success
and an error number for failure.
Parameters
lock-
pointer to the reader-writer lock to be acquired
Errors
If any of the following conditions occurs,
rw_trywrlock fails and returns the corresponding value:
EBUSY-
the reader-writer lock pointed to by lock cannot be acquired
If the following condition is detected,
rw_trywrlock returns the corresponding value:
EINVAL-
invalid argument specified
For consistency, locks acquired with rw_trywrlock should be released
with rw_unlock.
References
Intro(3synch),
rwlock(3synch),
rwlock_destroy(3synch),
rwlock_init(3synch),
rw_rdlock(3synch),
rw_tryrdlock(3synch),
rw_unlock(3synch),
rw_wrlock(3synch)
© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 25 April 2004