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PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
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SEM_CLOSE(3P) POSIX Programmer's Manual SEM_CLOSE(3P)
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.
sem_close — close a named semaphore
#include <semaphore.h>
int sem_close(sem_t *sem);
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 semaphore indicated
by sem by this process is undefined. If any threads in the calling
process are currently blocked on the semaphore, the behavior 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 semaphore
is no longer accessible.
Upon successful completion, a value of zero shall be returned.
Otherwise, a value of -1 shall be returned and errno set to
indicate the error.
The sem_close() function may fail if:
EINVAL The sem argument is not a valid semaphore descriptor.
The following sections are informative.
None.
None.
None.
None.
semctl(3p), semget(3p), semop(3p), sem_init(3p), sem_open(3p),
sem_unlink(3p)
The Base Definitions volume of POSIX.1‐2017, semaphore.h(0p)
Portions of this text are reprinted and reproduced in electronic
form from IEEE Std 1003.1-2017, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The
Open Group Base Specifications Issue 7, 2018 Edition, Copyright
(C) 2018 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.opengroup.org/unix/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 2017 SEM_CLOSE(3P)
Pages that refer to this page: semaphore.h(0p), _Exit(3p), semctl(3p), semget(3p), semop(3p), sem_open(3p), sem_unlink(3p)
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HTML rendering created 2025-02-02 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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