CodeUtility
Making your developer's life easier!
Important Rust Topics

Rust Channels: mpsc

Send messages from one thread to another instead of sharing memory.

  • Advanced
  • 2 min read
  • 1 runnable example
What you'll learn
  • mpsc::channel
  • send and receive
  • How a channel closes
Run code →
Producer to main
  1. 1sender.sendproducer thread
  2. 2channelstep 1, step 2, step 3
  3. 3for message in receivermain thread

A one-way pipe between threads

A channel is a one-way pipe between threads. One side sends values and the other receives them, so threads can work together without sharing memory.

channel returns a sender and a receiver. The producer thread owns the sender and sends three messages. When the thread ends, the sender is dropped and the channel closes, which ends the for loop over the receiver.

Key points

  1. channel() returns a sender and a receiver.
  2. The receiver can be used in a for loop.
  3. Dropping the sender closes the channel.

Runnable Rust example

Rust
Run code →
main.rs
use std::sync::mpsc;
use std::thread;

fn main() {
    let (sender, receiver) = mpsc::channel();

    let producer = thread::spawn(move || {
        for step in 1..=3 {
            sender.send(format!("step {step} done")).unwrap();
        }
    }); // sender is dropped here, which closes the channel

    for message in receiver {
        println!("received: {message}");
    }
    producer.join().unwrap();
    println!("all messages received");
}
Get a Run button for this example Result of running the code
received: step 1 done
received: step 2 done
received: step 3 done
all messages received

Practice

Open the example in the online compiler, change a value or add a line, and predict the output before you run it. Then break the code on purpose and read the compiler's message.

Finished this lesson?

Mark it as learned to track your progress.

Next: Shared State with Arc and Mutex →

Practice with a challenge

Use what this lesson covers to solve a real problem. Each challenge runs in your browser with instant tests and an AI review.

All challenges