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>

COPYRIGHT

       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 .