BufRead::read_line() doesn't work when timeout is set to 0

[Bktero]

Hello

I have a code like this:

let port = serialport::new(port_name, baud_rate)
    .timeout(Duration::from_millis(0)) // ----- NO TIMEOUT HERE
    .open()
    .expect("Error: ");

let mut port = BufReader::new(port);
let mut line_buffer = String::new();

match port.read_line(&mut line_buffer) {
    Ok(size) => println!("{} bytes read -> {:?}", size, line_buffer),
    Err(e) => eprintln!("Error while reading: {:?}", e),
}

It will never receive a line. Change the timeout to any value and the line will be received (apparently, when the timeout expires).

This behavior doesn't seem intuitive to me.

[Egor Starovoitov]

I believe it is necessary to avoid zero timeouts, perhaps it is worth adding a corresponding 'assert' into the '.timeout()'.

[Daniel]

Timeout means it immediately returns, and will never read a line.