SEM_POST(3) Linux Programmers Manual SEM_POST(3)
sem_post - unlock a semaphore
int sem_post(sem_t *sem);
Link with -lrt or -pthread.
sem_post() increments (unlocks) the semaphore pointed to by sem. If
the semaphores 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.
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
EINVAL sem is not a valid semaphore.
sem_post() is async-signal-safe: it may be safely called within a sig
sem_getvalue(3), sem_wait(3), sem_overview(7)
This page is part of release 3.05 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/.
Linux 2008-05-29 SEM_POST(3)