SEM_UNLINK(3P)                                      POSIX Programmer's Manual                                     SEM_UNLINK(3P)



PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (con-
       sult the corresponding Linux manual page for details of Linux behavior), or the  interface  may  not  be  implemented  on
       Linux.

NAME
       sem_unlink - remove a named semaphore (REALTIME)

SYNOPSIS
       #include <semaphore.h>

       int sem_unlink(const char *name);


DESCRIPTION
       The  sem_unlink()  function  shall  remove the semaphore named by the string name. If the semaphore named by name is cur-
       rently referenced by other processes, then sem_unlink() shall have no effect on the state of the  semaphore.  If  one  or
       more  processes  have the semaphore open when sem_unlink() is called, destruction of the semaphore is postponed until all
       references to the semaphore have been destroyed by calls to sem_close(), _exit(), or exec. Calls to sem_open() to  recre-
       ate  or reconnect to the semaphore refer to a new semaphore after sem_unlink() is called. The sem_unlink() call shall not
       block until all references have been destroyed; it shall return immediately.

RETURN VALUE
       Upon successful completion, the sem_unlink() function shall return a value of 0. Otherwise, the semaphore  shall  not  be
       changed and the function shall return a value of -1 and set errno to indicate the error.

ERRORS
       The sem_unlink() function shall fail if:

       EACCES Permission is denied to unlink the named semaphore.

       ENAMETOOLONG
              The length of the name argument exceeds {PATH_MAX} or a pathname component is longer than {NAME_MAX}.

       ENOENT The named semaphore does not exist.


       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       The sem_unlink() function is part of the Semaphores option and need not be available on all implementations.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       semctl(), semget(), semop(), sem_close(), sem_open(), the Base Definitions volume of IEEE Std 1003.1-2001, <semaphore.h>

COPYRIGHT
       Portions  of  this  text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for
       Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6,  Copy-
       right (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any
       discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open  Group
       Standard   is   the   referee   document.   The   original   Standard   can   be   obtained  online  at  http://www.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                SEM_UNLINK(3P)