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sem_close(3p) — Linux manual page

SEM_CLOSE(3P)           POSIX Programmer's ManualSEM_CLOSE(3P)

PROLOG        top

       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        top

       sem_close — close a named semaphore

SYNOPSIS        top

       #include <semaphore.h>       int sem_close(sem_t *sem);

DESCRIPTION        top

       Thesem_close() function shall indicate that the calling process       is finished using the named semaphore indicated bysem.  The       effects of callingsem_close() for an unnamed semaphore (one       created bysem_init()) are undefined. Thesem_close() function       shall deallocate (that is, make available for reuse by a       subsequentsem_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       bysem 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 tosem_unlink(), thensem_close() has no effect on       the state of the semaphore. If thesem_unlink() function has been       successfully invoked forname after the most recent call tosem_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        top

       Upon successful completion, a value of zero shall be returned.       Otherwise, a value of -1 shall be returned anderrno set to       indicate the error.

ERRORS        top

       Thesem_close() function may fail if:EINVALThesem argument is not a valid semaphore descriptor.The following sections are informative.

EXAMPLES        top

       None.

APPLICATION USAGE        top

       None.

RATIONALE        top

       None.

FUTURE DIRECTIONS        top

       None.

SEE ALSO        top

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        top

       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 athttp://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, seehttps://www.kernel.org/doc/man-pages/reporting_bugs.html .IEEE/The Open Group                2017SEM_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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