Semaphores Synchronizing

#include <semaphore.h>
int sem_init(sem_t *sem, int pshared, unsigned int value);
int sem_wait(sem_t *sem);
int sem_post(sem_t *sem);
int sem_destroy(sem_t *sem);

• sem_init() initializes an unnamed semaphore at the address given by sem. The value argument specifies the initial value of the semaphore.

• sem_wait() decrements (locks) the semaphore pointed to by sem. If the semaphore value is zero, the call blocks until the semaphore becomes positive.

• sem_post() increments (unlocks) the semaphore pointed to by sem.

• sem_destroy() destroys the unnamed semaphore at the address given by sem.