mutex_trylock(SYNCH)

mutex_trylock -- conditionally lock a mutex

Synopsis

   cc [options] -Kthread file
   
   #include <synch.h>
   

   int mutex_trylock(mutex_t *mutex);

Description

mutex_trylock attempts once to lock the mutual exclusion lock (mutex) pointed to by mutex.

Parameters

mutex: pointer to mutex to be locked

If mutex is available, mutex_trylock will return successfully with mutex locked. If mutex is already locked, mutex_trylock immediately returns EBUSY to the caller without acquiring mutex or blocking.

mutex must previously have been initialized, either by mutex_init, or statically (see mutex_init(SYNCH)).

Usage

mutex_trylock is used when the caller does not want to block.

Mutexes acquired with mutex_trylock should be released with mutex_unlock.

Return values

mutex_trylock returns zero for success and an error number for failure.

Errors

If the following condition occurs, mutex_trylock returns the corresponding value:

EBUSY: mutex is already locked

If the following condition is detected, mutex_trylock fails and returns the corresponding value:

EINVAL: invalid argument specified

References

Intro(SYNCH), mutex(SYNCH), mutex_destroy(SYNCH), mutex_init(SYNCH), mutex_lock(SYNCH), mutex_unlock(SYNCH)