Asynchronous signal handling.

This crate provides the Signals type, which can be used to listen for POSIX signals asynchronously. It can be seen as an asynchronous version of signal_hook::iterator::Signals.

On unix, this crate uses the signal_hook_registry crate to register a listener for each signal. That listener will then send a message through a Unix socket to the Signals type, which will receive it and notify the user. Asynchronous notification is done through the async-io crate.

Note that the internal pipe has a limited capacity. Once it has reached capacity, additional signals will be dropped.

On Windows, a different implementation that only supports SIGINT is used. This implementation uses a channel to notify the user.

use async_signal::{Signal, Signals};
use futures_lite::prelude::*;
use signal_hook::low_level;

// Register the signals we want to receive.
let mut signals = Signals::new([
    Signal::Term,
    Signal::Quit,
    Signal::Int,
])?;

// Wait for a signal to be received.
while let Some(signal) = signals.next().await {
    // Print the signal.
    eprintln!("Received signal {:?}", signal);

    // After printing it, do whatever the signal was supposed to do in the first place.
    low_level::emulate_default_handler(signal.unwrap() as i32).unwrap();
}

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

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.