sem_close(3p) — Linux manual page

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.

NAME

       sem_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 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.

RETURN VALUE

       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.

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 ALSO

       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)

COPYRIGHT

       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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