include "lock.m";
lock := load Lock Lock->PATH;
Semaphore: adt {
	c: chan of int;
	obtain: fn(s: self ref Semaphore);
	release: fn(s: self ref Semaphore);
	new: fn(): ref Semaphore;
};
init: fn();

Semaphore.new()

Creates and returns a reference to a new Semaphore (lock).

s.obtain()

Obtains exclusive access to the lock s. It will block until it can do so.

s.release()

Releases access to the lock s and allows processes waiting on it to proceed.