This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface

       None.

       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(3POSIX)

       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.

       The sem_close() function may fail if:

       EINVAL The sem argument is not a valid semaphore descriptor.

       Thefollowingsectionsareinformative.

       None.

       None.

       sem_close — close a named semaphore

       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.

       None.

       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.

semctl(), semget(), semop(), sem_init(), sem_open(), sem_unlink()

       The Base Definitions volume of POSIX.1‐2017, <semaphore.h>

       #include <semaphore.h>

       int sem_close(sem_t *sem);