| lib.rs |
Thread parking and unparking.
A [`Parker`] is in either the notified or unnotified state. The [`park()`][`Parker::park()`] method blocks
the current thread until the [`Parker`] becomes notified and then puts it back into the unnotified
state. The [`unpark()`][`Unparker::unpark()`] method puts it into the notified state.
This API is similar to [`thread::park()`] and [`Thread::unpark()`] from the standard library.
The difference is that the state "token" managed by those functions is shared across an entire
thread, and anyone can call [`thread::current()`] to access it. If you use `park` and `unpark`,
but you also call a function that uses `park` and `unpark` internally, that function could
cause a deadlock by consuming a wakeup that was intended for you. The [`Parker`] object in this
crate avoids that problem by managing its own state, which isn't shared with unrelated callers.
[`thread::park()`]: https://doc.rust-lang.org/std/thread/fn.park.html
[`Thread::unpark()`]: https://doc.rust-lang.org/std/thread/struct.Thread.html#method.unpark
[`thread::current()`]: https://doc.rust-lang.org/std/thread/fn.current.html
# Examples
```
use std::thread;
use std::time::Duration;
use parking::Parker;
let p = Parker::new();
let u = p.unparker();
// Notify the parker.
u.unpark();
// Wakes up immediately because the parker is notified.
p.park();
thread::spawn(move || {
thread::sleep(Duration::from_millis(500));
u.unpark();
});
// Wakes up when `u.unpark()` notifies and then goes back into unnotified state.
p.park();
``` |
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