PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of this interface
       may differ (consult 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

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  currently 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 recreate 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.

       ENOENT The named semaphore does not exist.

       The sem_unlink() function may fail if:

       ENAMETOOLONG
              The length of the name argument exceeds {_POSIX_PATH_MAX} on systems that do not support  the  XSI
              option  or  exceeds  {_XOPEN_PATH_MAX}  on XSI systems, or has a pathname component that is longer
              than  {_POSIX_NAME_MAX}  on  systems  that  do  not  support  the  XSI  option  or   longer   than
              {_XOPEN_NAME_MAX}  on  XSI systems.  A call to sem_unlink() with a name argument that contains the
              same semaphore name as was previously used in a successful  sem_open()  call  shall  not  give  an
              [ENAMETOOLONG] error.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       A  future  version  might  require the sem_open() and sem_unlink() functions to have semantics similar to
       normal file system operations.

SEE ALSO

       semctl(), semget(), semop(), sem_close(), sem_open()

       The Base Definitions volume of POSIX.1‐2008, <semaphore.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition,
       Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open  Group  Base
       Specifications  Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc
       and The Open Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/online.html .

       Any typographical or formatting errors that appear in this page are most likely to have  been  introduced
       during   the   conversion  of  the  source  files  to  man  page  format.  To  report  such  errors,  see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                                   2013                                    SEM_UNLINK(3POSIX)