sem_close(2) — DG/UX 5.4R3.00



sem_close(2)                   DG/UX 5.4R3.00                   sem_close(2)


NAME
       semclose - close access to a named semaphore

SYNOPSIS
       #include <semaphore.h>

       int semclose (*sem)
            semt  *sem;

   where:
       sem    A valid semaphore address returned by a prior semopen(2)
              call.

DESCRIPTION
       Use semclose(2) to indicate that your process is finished using a
       semaphore.

       After making this call, your process cannot again access the
       semaphore indicated by sem without first calling semopen(2).

       Whenever a process calls exit(2) or exec(2), an implicit semclose(2)
       is made on all its named semaphores.

       This call closes but does not remove or affect the state of a
       semaphore.  However, if a process calls semunlink(2) to remove a
       semaphore, the removal takes place as soon as the last of the
       processes attached to the semaphore calls semclose(2), exit(2), or
       exec(2).

   Note
        * This routine is based on POSIX realtime extension document P1003.4
          draft 14. It is therefore subject to change.

        * Compilation of a source file using this routine requires that
          feature macro _POSIX4_DRAFT_SOURCE be defined.  This feature macro
          is not enabled by any other feature macro, nor does it enable any
          other feature macro.

        * The compiled routine must be linked to library librte.a.

RETURN VALUE
       If successful, semclose returns 0. If unsuccessful, it returns -1
       and sets ERRNO to:

        EINVAL sem is not a valid named semaphore.

SEE ALSO
       semopen(2), semwait(2), semtrywait(2), sempost(2), semunlink(2),
       semdestroy(2).








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