Channels

Channel functionality is limited in the standard library. For multiple-producer multiple-consumer channels and other concurrent utilities, check out the crossbeam crate.

Rust channels have two parts: a Sender<T> and a Receiver<T>. The two parts are connected via the channel, but you only see the end-points.

use std::sync::mpsc;

fn main() {
    let (tx, rx) = mpsc::channel();

    tx.send(10).unwrap();
    tx.send(20).unwrap();

    println!("Received: {:?}", rx.recv());
    println!("Received: {:?}", rx.recv());

    let tx2 = tx.clone();
    tx2.send(30).unwrap();
    println!("Received: {:?}", rx.recv());
}
  • mpsc stands for Multi-Producer, Single-Consumer. Sender and SyncSender implement Clone (so you can make multiple producers) but Receiver does not.
  • send() and recv() return Result. If they return Err, it means the counterpart Sender or Receiver is dropped and the channel is closed.