rx</span>.<span class='ident'>recv</span>().<span class='ident'>is_err</span>());</pre>

<p>Synchronous channels:</p>
<span class='rusttest'>fn main() {
    use std::thread;
    use std::sync::mpsc::sync_channel;
    
    let (tx, rx) = sync_channel::&lt;i32&gt;(0);
    thread::spawn(move|| {
        // This will wait for the parent thread to start receiving
        tx.send(53).unwrap();
    });
    rx.recv().unwrap();
    
}</span><pre class='rust rust-example-rendered'>
<span class='kw'>use</span> <span c