Async I/O and timers.
This crate provides two tools:
Async, an adapter for standard networking types (and many other types) to use in async programs.Timer, a future that expires at a point in time.
For concrete async networking types built on top of this crate, see async-net.
The first time Async or Timer is used, a thread named "async-io" will be spawned.
The purpose of this thread is to wait for I/O events reported by the operating system, and then
wake appropriate futures blocked on I/O or timers when they can be resumed.
To wait for the next I/O event, the "async-io" thread uses epoll on Linux/Android/illumos,
kqueue on macOS/iOS/BSD, event ports on illumos/Solaris, and IOCP on Windows. That
functionality is provided by the polling crate.
However, note that you can also process I/O events and wake futures on any thread using the
block_on() function. The "async-io" thread is therefore just a fallback mechanism
processing I/O events in case no other threads are.
Connect to example.com:80, or time out after 10 seconds.
use async_io::{Async, Timer};
use futures_lite::{future::FutureExt, io};
use std::net::{TcpStream, ToSocketAddrs};
use std::time::Duration;
let addr = "example.com:80".to_socket_addrs()?.next().unwrap();
let stream = Async::<TcpStream>::connect(addr).or(async {
Timer::after(Duration::from_secs(10)).await;
Err(io::ErrorKind::TimedOut.into())
})
.await?;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.