_lwp_mutex_trylock(2)                          _lwp_mutex_trylock(2)


       NAME
             _lwp_mutex_trylock - conditionally lock a mutex

       SYNOPSIS
             #include <synch.h>
             int _lwp_mutex_trylock(lwp_mutex_t *mutex);

          Parameters
             mutex pointer to mutex to be locked

       DESCRIPTION
             _lwp_mutex_trylock, is used to conditionally apply a mutual
             exclusion lock (mutex) on behalf of the calling lightweight
             process (LWP).  The parameter mutex points to the mutex on
             which the lock is to be applied.

             The mutex must previously have been initialized.  A
             lwp_mutex_t object filled with zeros (for example, by static
             initialization) is a valid unlocked setting.  If the mutex is
             already locked upon entry, the operation immediately returns
             to the caller without acquiring the lock.

          Return Values
             _lwp_mutex_trylock returns zero on success and an error number
             for failure, as described below.

          Errors
             If any of the following conditions is detected,
             _lwp_mutex_trylock fails and returns the corresponding value:

             EINVAL   The mutual exclusion variable pointed to by mutex is
                      invalid.

             EFAULT   The mutex parameter points to an illegal address.
                      (This error may not be detected; a SIGSEGV signal may
                      be posted to the faulting LWP if an illegal address
                      is used.)

             If any of the following conditions occur, _lwp_mutex_trylock
             fails and returns the corresponding value:

             EBUSY The parameter mutex points to a locked mutex.

       USAGE
             _lwp_mutex_trylock is used when the caller does not want to
             block.


                           Copyright 1994 Novell, Inc.               Page 1

      _lwp_mutex_trylock(2)                          _lwp_mutex_trylock(2)


            For consistency, mutexes acquired with _lwp_mutex_trylock
            should be released with _lwp_mutex_unlock.

      REFERENCES
            _lwp_mutex_lock(2), _lwp_mutex_unlock(2),
            mutex_destroy(3synch), mutex_init(3synch), mutex_lock(3synch),
            mutex_trylock(3synch), mutex_unlock(3synch)

      NOTICES
            Lightweight processes (LWPs) are internal interfaces and are
            subject to change.  Their use should be avoided.





































                          Copyright 1994 Novell, Inc.               Page 2