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.
NAMEsem_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 ALSOsemctl(), 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)
