Comparison of Semaphores & Monitors:

Monitors               | Semaphore
-----------------------|----------------
locks                  | Binary Semaphore
condition variable     | See below
L.lock();              |
while(!cond)           | sem.down(); // don't surround with a lock!
	cv.wait.(L);   |
L.unlock();            |

What if cond doesn't map well to testing an integer? Well...

// semaphore code

semaphore mutex(1);
queue<semaphore*> waitingSems;

...

// moral equivalent of "wait"
mutex.down();				// L.lock();
while(!cond) {				// while(!cond) { 
	semaphore s(0);			// wait
	waitingSems.push(&s);		// ...
	mutex.up();			// ...
	s.down();
	mutex.down();
}
<critical section>			// same
mutex.up();				// L.unlock();

// moral equivalent of "signal"
mutex.down();
<critical section>
while (!waitingSems.empty()) {
	waitingSems.front()->up();
	waitingSems.pop();
}
mutex.up();