Re:This Week in Rust – Static linking, Win64
by portmanteaufu on Sunday December 01, 2013 @08:33PM
(#6830628)
I read about this in the mailing list, but never having relied on linked failure in the past I wasn't sure what the implications were. Could someone give an example of when this would've been used before and how you might accomplish the same in its absence?
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Re:This Week in Rust – Static linking, Win64
by eridius on Sunday December 01, 2013 @09:27PM
(#6831027)
With linked task failure, this program here would cause the main task to fail, which results in the entire program aborting (once all tasks have finished failing):
fn main() {
// we can't introduce synchronization for this example, so print repeatedly on the main task and check the output for ordering
do spawn {
fail!("child task failure");
}
for i in range(0u, 50) {
println!("print line {}", i);
}
}
If you want to reintroduce linked task failure with current master, you can do so explicitly using `std::task::TaskBuilder.future_result()`. It's a bit awkward though. And you can probably do better than what I have here, it's just a quick sample:
fn main() {
let mut builder = std::task::task();
let future = builder.future_result();
do builder.spawn() {
fail!("child task failure");
}
// check for failure before each of our prints
for i in range(0u, 50) {
if future.peek() && future.recv().is_err() {
fail!("parent task failing because of child failure");
}
println!("print line {}", i);
}
// and block on the result in the end
if future.try_recv().map_default(false, |r| r.is_err()) {
fail!("parent task failing because of child failure");
}
}