SEM_CLOSE(3P) POSIX Programmer's Manual SEM_CLOSE(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_close — close a named semaphore
SYNOPSIS
#include <semaphore.h>
int sem_close(sem_t *sem);
DESCRIPTION
The sem_close() function shall indicate that the calling process is
finished using the named semaphore indicated by sem. The effects of
calling sem_close() for an unnamed semaphore (one created by
sem_init()) are undefined. The sem_close() function shall deallocate
(that is, make available for reuse by a subsequent sem_open() by this
process) any system resources allocated by the system for use by this
process for this semaphore. The effect of subsequent use of the sema‐
phore indicated by sem by this process is undefined. If the semaphore
has not been removed with a successful call to sem_unlink(), then
sem_close() has no effect on the state of the semaphore. If the
sem_unlink() function has been successfully invoked for name after the
most recent call to sem_open() with O_CREAT for this semaphore, then
when all processes that have opened the semaphore close it, the sema‐
phore is no longer accessible.
RETURN VALUE
Upon successful completion, a value of zero shall be returned. Other‐
wise, a value of −1 shall be returned and errno set to indicate the
error.
ERRORS
The sem_close() function may fail if:
EINVAL The sem argument is not a valid semaphore descriptor.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSOsemctl(), semget(), semop(), sem_init(), sem_open(), sem_unlink()
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_CLOSE(3P)
