rust/src/test/run-pass/preempt.rs

// xfail-test
// This checks that preemption works.

fn starve_main(alive: chan<int>) {
    debug!{"signalling main"};
    alive <| 1;
    debug!{"starving main"};
    let i: int = 0;
    loop { i += 1; }
}

fn main() {
    let alive: port<int> = port();
    debug!{"main started"};
    let s: task = spawn starve_main(chan(alive));
    let i: int;
    debug!{"main waiting for alive signal"};
    alive |> i;
    debug!{"main got alive signal"};
    while i < 50 { debug!{"main iterated"}; i += 1; }
    debug!{"main completed"};
}