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SEM_GETVALUE(3)	       FreeBSD Library Functions Manual	       SEM_GETVALUE(3)

NAME
     sem_getvalue -- get the value of a	semaphore

LIBRARY
     Standard C	Library	(libc, -lc)

SYNOPSIS
     #include <semaphore.h>

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

DESCRIPTION
     The sem_getvalue()	function sets the variable pointed to by sval to the
     current value of the semaphore pointed to by sem, as of the time that the
     call to sem_getvalue() is actually	run.

RETURN VALUES
     The sem_getvalue()	function returns the value 0 if	successful; otherwise
     the value -1 is returned and the global variable errno is set to indicate
     the error.

ERRORS
     The sem_getvalue()	function will fail if:

     [EINVAL]		The sem	argument points	to an invalid semaphore.

SEE ALSO
     sem_post(3), sem_trywait(3), sem_wait(3), sem(4)

STANDARDS
     The sem_getvalue()	function conforms to ISO/IEC 9945-1:1996
     (``POSIX.1'').

     The value of the semaphore	is never negative, even	if there are threads
     blocked on	the semaphore.	POSIX is somewhat ambiguous in its wording
     with regard to what the value of the semaphore should be if there are
     blocked waiting threads, but this behavior	is conformant, given the word-
     ing of the	specification.

FreeBSD	9.3		       February	15, 2000		   FreeBSD 9.3

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | SEE ALSO | STANDARDS

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