sigsem(2XNX)        (XENIX System Compatibility)        sigsem(2XNX)


       NAME
             sigsem - (XENIX) signal a process waiting on a semaphore

       SYNOPSIS
             cc [flag . . . ] flag . . . -lx
             int sigsem(int sem_num);

       DESCRIPTION
             sigsem signals a process that is waiting on the semaphore
             sem_num that it may proceed and use the resource governed by
             the semaphore.  sigsem is used in conjunction with waitsem to
             allow synchronization of processes wishing to access a
             resource.  One or more processes may waitsem on the given
             semaphore and will be put to sleep until the process which
             currently has access to the resource issues a sigsem call.  If
             there are any waiting processes, sigsem causes the process
             which is next in line on the semaphore's queue to be
             rescheduled for execution.  The semaphore's queue is organized
             in First In, First Out (FIFO) order.

          Return Values
             sigsem returns the value (int) -1 if an error occurs.  If
             sem_num does not refer to a semaphore type file, errno is set
             to ENOTNAM.  If sem_num has not been previously opened by
             opensem, errno is set to EBADF.  If the process issuing a
             sigsem call is not the current ``owner'' of the semaphore
             (that is, if the process has not issued a waitsem call before
             the sigsem), errno is set to ENAVAIL.

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

















                           Copyright 1994 Novell, Inc.               Page 1