Process never exits after successfully receiving from MPSC channel

Question

Here\'s the code:

use std::thread;
use std::sync::mpsc;

fn main() {

    //spawn threads 
    let (tx, rx) = mpsc::chann         


        

Answer 1

tx in your main thread is not dropped until the end of the main function, and rx will not be closed until all senders have been dropped.

To fix this, you can manually drop it with drop(tx) after you have started all of your threads:

use std::thread;
use std::sync::mpsc;

fn main() {

    //spawn threads 
    let (tx, rx) = mpsc::channel();
    for mut i in 0 .. 10 {
        let txc = tx.clone();   //clone from the main sender
        thread::spawn( move || {            
            i += 20;
            println!("Sending: {}", i);
            txc.send(i).unwrap_or_else(|e| {
                eprintln!("{}", e);
            });
        });
    }

    // drop tx manually, to ensure that only senders in spawned threads are still in use
    drop(tx);

    for received in rx {
        println!("Received: {}", received);
    }

}