Semaphores as Mutexes

semapohore->Init(1);

void Lock::Acquire()

{

semaphore->Down();

}

void Lock::Release()

{

semaphore->Up();

}

Semaphores must be initialized with a value representing the number of free resources: mutexes are a single-use resource.

Down() to acquire a resource; blocks if

no resource is available.

Up() to release a resource; wakes up one waiter, if any.

Mutexes are often called binary semaphores.

However, “real” mutexes have additional constraints on their use.

Up and Down are atomic.