mentalboy@geocities.com
key_t ftok(char *pathname, char proj_id);
int semget(key_t key, int nsems, int flags);
int semctl(int semset_id, int sem_number, int command, union semun arg);
int semop(int semset_id, struct sembuf *semops, unsigned nsops);
int sem_init(sem_t *sem, int pshared, unsigned int value);
int sem_wait(sem_t *sem);
int sem_trywait(sem_t *sem);
int sem_post(sem_t *sem);
int sem_getvalue(sem_t *sem, int *valp);
int sem_destroy(sem_t *sem);