Timer facilities should have a sleep_until method

[mstewartgallus]

A sleep_until method for periodic timing without drifting is needed. In many cases this is much better to use than the sleep function. The Ada Ravenscar profile even forbids the use of the delay facility because it is so less predictable, and often leads to broken code. Currently, there is a periodic method one can use but for more complicated cases one would still need the sleep_until function.

Sample usage of the hypothetical sleep_until:

fn periodic(t : Timer) {
     let mut next_tick = time::precise_time_ns() / 100_000;
     loop {
          // .... Tick code

          next_tick += 100;
          timer.sleep_until(next_tick);
     }
}

Wikipedia example of delay causing clock drift http://en.wikibooks.org/wiki/Ada_Style_Guide/Concurrency#Delay_Statements

[thestinger]

Rust's timers won't be very precise anyway, due to the scheduling model. I think real-time use cases are better suited by an alternate standard library profile.

[steveklabnik]

Triage: timers are no longer in the standard library at all. Closing.