# event-listener
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Notify async tasks or threads.
This is a synchronization primitive similar to [eventcounts] invented by Dmitry Vyukov.
You can use this crate to turn non-blocking data structures into async or blocking data
structures. See a [simple mutex] implementation that exposes an async and a blocking interface
for acquiring locks.
[eventcounts]: http://www.1024cores.net/home/lock-free-algorithms/eventcounts
[simple mutex]: ./examples/mutex.rs
## Examples
Wait until another thread sets a boolean flag:
```rust
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::Arc;
use std::thread;
use std::time::Duration;
use event_listener::Event;
let flag = Arc::new(AtomicBool::new(false));
let event = Arc::new(Event::new());
// Spawn a thread that will set the flag after 1 second.
thread::spawn({
let flag = flag.clone();
let event = event.clone();
move || {
// Wait for a second.
thread::sleep(Duration::from_secs(1));
// Set the flag.
flag.store(true, Ordering::SeqCst);
// Notify all listeners that the flag has been set.
event.notify(usize::MAX);
}
});
// Wait until the flag is set.
loop {
// Check the flag.
if flag.load(Ordering::SeqCst) {
break;
}
// Start listening for events.
let listener = event.listen();
// Check the flag again after creating the listener.
if flag.load(Ordering::SeqCst) {
break;
}
// Wait for a notification and continue the loop.
listener.wait();
}
```
## License
Licensed under either of
* Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
* MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
at your option.
#### Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in the work by you, as defined in the Apache-2.0 license, shall be
dual licensed as above, without any additional terms or conditions.