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(* From Patrick M Doane *)
(* This example demonstrates an important property of Unixqueue:
the queues are thread-safe. Even better, one can add event from
one thread into a running Unixqueue that is being executed by
a different thread. This "event injection" will interrupt the
queue if it is waiting, and makes it consider the additional event.
*)
let esys = Unixqueue.create_unix_event_system()
let after timeout f =
let group = Unixqueue.new_group esys in
Unixqueue.once esys group timeout f
;;
let m = Mutex.create();;
let c = Condition.create();;
(* Unixqueue.run should not be called before any event handlers are
* registered; it would return immediately. The condition variable
* is used to wait until the first handler is added to the queue.
*)
let queue_it () =
print_endline "queue_it started"; flush stdout;
after 4.0 (fun () -> print_endline "4 seconds"; flush stdout);
Mutex.lock m;
Condition.signal c;
Mutex.unlock m;
Thread.delay 1.0;
print_endline "1 second"; flush stdout;
(* The following is an event injection from a different thread: *)
after 1.0 (fun () -> print_endline "2 seconds"; flush stdout);
print_endline "queue_it finishes"; flush stdout;
;;
let run_it () =
print_endline "run_it started"; flush stdout;
Condition.wait c m;
print_endline "run_it executes event system"; flush stdout;
Unixqueue.run esys;
print_endline "run_it finishes"; flush stdout;
;;
Mutex.lock m;;
let t1 = Thread.create queue_it ();;
let t2 = Thread.create run_it ();;
Thread.join t1;
Thread.join t2
|
