SEM_POST(2) System Calls Manual SEM_POST(2)

sem_postunlock a semaphore

#include <semaphore.h>

sem_post(sem_t *sem);

The semaphore referenced by sem is unlocked, the value of the semaphore is incremented, and all threads which are waiting on the semaphore are awakened.

() is reentrant with respect to signals and may be called from within a signal hanlder.

If successful, () will return 0. Otherwise, -1 is returned and errno is set.

sem_post() succeeds unless:

sem is not a valid semaphore descriptor.

sem_open(2), sem_trywait(2), sem_wait(2), semctl(2), semget(2), semop(2)

sem_post() is specified in the POSIX Realtime Extension (1003.1b-1993/1003.1i-1995).

June 8, 2000 Darwin