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

       sem_getvalue - get the value of a semaphore (REALTIME)

       #include <semaphore.h>

       int sem_getvalue(sem_t *restrict sem, int *restrict sval);

       The  sem_getvalue()  function shall update the location referenced by the sval argument to
       have the value of the semaphore referenced by sem without affecting the state of the sema-
       phore.  The  updated  value  represents	an  actual  semaphore value that occurred at some
       unspecified time during the call, but it need not be the actual	value  of  the	semaphore
       when it is returned to the calling process.

       If sem is locked, then the object to which sval points shall either be set to zero or to a
       negative number whose absolute value represents the number of processes	waiting  for  the
       semaphore at some unspecified time during the call.

       Upon successful completion, the sem_getvalue() function shall return a value of zero. Oth-
       erwise, it shall return a value of -1 and set errno to indicate the error.

       The sem_getvalue() function shall fail if:

       EINVAL The sem argument does not refer to a valid semaphore.

       The following sections are informative.


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



       semctl()  , semget() , semop() , sem_post() , sem_timedwait() , sem_trywait() , sem_wait()
       , the Base Definitions 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_GETVALUE(P)
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