sunos man page for sem_getvalue

sem_getvalue(3RT)					    Realtime Library Functions						 sem_getvalue(3RT)

NAME
       sem_getvalue - get the value of a semaphore

SYNOPSIS
       cc [ flag... ] file... -lrt [ library... ]
       #include <semaphore.h>

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

DESCRIPTION
       The sem_getvalue() function updates the location referenced by the sval argument to have the value of the semaphore referenced by sem with-
       out affecting the state of the semaphore. 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 value returned by sem_getvalue() is either zero or a negative number whose absolute value represents the number
       of processes waiting for the semaphore at some unspecified time during the call.

       The value set in sval may be 0 or positive. If sval is 0, there may be other processes (or LWPs or threads) waiting for the  semaphore;	if
       sval is positive, no process is waiting.

RETURN VALUES
       Upon successful completion, sem_getvalue() returns 0. Otherwise, it returns -1 and sets errno to indicate the error.

ERRORS
       The  sem_getvalue() function will fail if:

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

       ENOSYS	       The sem_getvalue() function is not supported by the system.

ATTRIBUTES
       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+

SEE ALSO
       semctl(2), semget(2), semop(2), sem_post(3RT), sem_wait(3RT), attributes(5), standards(5)

SunOS 5.10							    1 Nov 2003							 sem_getvalue(3RT)