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Asynchronous signal handling

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async-signal

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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.

Implementation

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.

Examples

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

// Register the signals we want to receive.
let 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();
}

License

Licensed under either of

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.