%% ---
%%  Excerpted from "Programming Erlang",
%%  published by The Pragmatic Bookshelf.
%%  Copyrights apply to this code. It may not be used to create training material, 
%%  courses, books, articles, and the like. Contact us if you are in doubt.
%%  We make no guarantees that this code is fit for any purpose. 
%%  Visit http://www.pragmaticprogrammer.com/titles/jaerlang for more book information.
%%---
-module(stimer).
-export([start/2, cancel/1]).

% After Time milliseconds have elapsed, executes the function Fun
% (the result is not communicated back, so Fun is only useful for its
% side effects).
start(Time, Fun) -> spawn(fun() -> timer(Time, Fun) end).

cancel(Pid) -> Pid ! cancel.

timer(Time, Fun) ->
    receive
	cancel ->
	    void
    after Time ->
	    Fun()
    end.