Name
sem_getvalue — get the value of a semaphore
Synopsis
#include <semaphore.h>
int
sem_getvalue( |
sem_t *sem, |
int *sval); |
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Note |
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DESCRIPTION
sem_getvalue() places the
current value of the semaphore pointed to sem into the integer pointed to
by sval.
If one or more processes or threads are blocked waiting to
lock the semaphore with sem_wait(3), POSIX.1-2001
permits two possibilities for the value returned in
sval: either 0 is
returned; or a negative number whose absolute value is the
count of the number of processes and threads currently
blocked in sem_wait(3). Linux adopts
the former behavior.
RETURN VALUE
sem_getvalue() returns 0 on
success; on error, −1 is returned and errno is set to indicate the error.
COLOPHON
This page is part of release 3.52 of the Linux man-pages project. A
description of the project, and information about reporting
bugs, can be found at
http://www.kernel.org/doc/man−pages/.
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