opensem(2XNX)       (XENIX System Compatibility)       opensem(2XNX)


       NAME
             opensem - (XENIX) open a semaphore

       SYNOPSIS
             cc [flag . . . ] flag . . . -lx
             int opensem(char *sem_name);

       DESCRIPTION
             opensem opens a semaphore named by sem_name and returns the
             unique semaphore identification number sem_num used by waitsem
             and sigsem.  creatsem should always be called to initialize
             the semaphore before the first attempt to open it.

          Return Values
             opensem returns a value of -1 if an error occurs.  If the
             semaphore named does not exist, errno is set to ENOENT.  If
             the file specified is not a semaphore file (that is, a file
             previously created by a process using a call to creatsem),
             errno is set to ENOTNAM.  If the semaphore has become invalid
             due to inappropriate use, errno is set to ENAVAIL.

       REFERENCES
             creatsem(2XNX), sigsem(2XNX), waitsem(2XNX)

       NOTICES
             It is not advisable to open the same semaphore more than once.
             Although it is possible to do this, it may result in a
             deadlock.




















                           Copyright 1994 Novell, Inc.               Page 1