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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 (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 func-
       tion 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  con-
              tains  the  same semaphore name as was previously used in a suc-
              cessful 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()  func-
       tions 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 Electri-
       cal  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.ker-
       nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group                  2013                       SEM_UNLINK(3P)