Unbounded Channels

You get an unbounded and asynchronous channel with mpsc::channel():

use std::sync::mpsc;
use std::thread;
use std::time::Duration;

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

    thread::spawn(move || {
        let thread_id = thread::current().id();
        for i in 0..10 {
            tx.send(format!("Message {i}")).unwrap();
            println!("{thread_id:?}: sent Message {i}");
        }
        println!("{thread_id:?}: done");
    });
    thread::sleep(Duration::from_millis(100));

    for msg in rx.iter() {
        println!("Main: got {msg}");
    }
}
This slide should take about 2 minutes.
  • An unbounded channel will allocate as much space as is necessary to store pending messages. The send() method will not block the calling thread.
  • A call to send() will abort with an error (that is why it returns Result) if the channel is closed. A channel is closed when the receiver is dropped.