sem_post
NAME
sem_post - unlock a semaphore
SYNOPSIS
#include <semaphore.h> I int sem_post(sem_t * sem );
DESCRIPTION
R sem_post ()
increments (unlocks) the semaphore pointed to by
R sem .
If the semaphore's value consequently becomes greater than zero,
then another process or thread blocked in a
sem_wait(3)
call will be woken up and proceed to lock the semaphore.
RETURN VALUE
R sem_post ()
returns 0 on success;
on error, the value of the semaphore is left unchanged,
-1 is returned, and
errno
is set to indicate the error.
ERRORS
EINVAL
sem
is not a valid semaphore.
CONFORMING TO
POSIX.1-2001.
NOTES
R sem_post ()
is async-signal-safe:
it may be safely called within a signal handler.
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