increment a semaphore
#include <semaphore.h> int sem_post( sem_t *sem );
The sem_post() function increments the semaphore referenced by the sem argument. If any processes are currently blocked waiting for the semaphore, one of these processes will return successfully from its call to sem_wait.
The process to be unblocked is determined in accordance with the scheduling policies in effect for the blocked processes. The highest priority waiting process is unblocked, and if there's more than one highest priority process blocked waiting for the semaphore, the highest priority process that has been waiting the longest is unblocked.
|Signal handler||Yes, but modifies errno|
errno, sem_destroy(), sem_init(), sem_trywait(), sem_wait()