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SEM_CLOSE(P)			    POSIX Programmer's Manual			     SEM_CLOSE(P)

       sem_close - close a named semaphore (REALTIME)

       #include <semaphore.h>

       int sem_close(sem_t *sem);

       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  sema-
       phore (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  suc-
       cessfully  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.

       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.

       The sem_close() function shall fail if:

       EINVAL The sem argument is not a valid semaphore descriptor.

       The following sections are informative.


       The sem_close() function is part of the Semaphores option and need not be available on all



       semctl()  , semget() , semop() , sem_init() , sem_open() , sem_unlink() , the Base Defini-
       tions volume of IEEE Std 1003.1-2001, <semaphore.h>

       Portions of this text are reprinted and	reproduced  in	electronic  form  from	IEEE  Std
       1003.1,	2003  Edition,	Standard  for Information Technology -- Portable Operating System
       Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003  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 orig-
       inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group			       2003				     SEM_CLOSE(P)
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