_lwp_sema_trywait(2)                            _lwp_sema_trywait(2)


       NAME
             _lwp_sema_trywait - conditionally acquire the semaphore

       SYNOPSIS
             #include <synch.h>
             int _lwp_sema_trywait(_lwp_sema_t *sema);

          Parameters
             sema

       DESCRIPTION
             _lwp_sema_trywait makes a single attempt to acquire the
             semaphore sema, but does not block in the case of a failure.

          sema Parameter
             sema must have been previously initialized, either by
             _lwp_sema_init or statically (see _lwp_sema_init).

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

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

             EBUSY    The semaphore is in the locked state.

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

       REFERENCES
             _lwp_sema_init(2), _lwp_sema_post(2), _lwp_sema_wait(2),
             sema_destroy(3synch), sema_init(3synch), sema_post(3synch),
             sema_trywait(3synch), sema_wait(3synch)

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







                           Copyright 1994 Novell, Inc.               Page 1