timer

import std::future::timer; · source

Sleep#

type struct Sleep {
    deadline: i64;
    id:       u64;
    rt:       Reactor*;

    static new(dur: Duration) -> Sleep;
    static until(deadline: Instant) -> Sleep;
    deadline_nanos(&this) -> i64;
    is_elapsed(&this) -> boolean;
}

The timer counterpart of an I/O future. Instead of asking the reactor to wake it when a descriptor becomes ready, it asks to be woken at a point on the monotonic clock. The reactor keeps those deadlines in a sorted chain and bounds its readiness wait by the earliest one, so a sleeping task costs no thread and no polling — the wait the reactor was already in simply ends sooner.

Deadlines are absolute, not durations: Sleep::new(dur) resolves dur against the clock once, at construction. A Sleep polled late, or polled many times, still completes at the instant it was created to complete at, and re-polling never extends it.

Dropping a Sleep disarms its registration. That is what makes it usable as the losing half of a select — the timer that did not win is dropped and its waker released immediately, rather than lingering until the deadline passes.

Trait implementations#

implement trait Future for struct Sleep

implement trait Drop for struct Sleep