bionic (3) sem_close.3posix.gz

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

       The Base Definitions volume of POSIX.1‐2008, <semaphore.h>


       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 Electrical 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.kernel.org/doc/man-pages/reporting_bugs.html .