scoped-threads.rs

fn main() {
    let x = String::from("foo");
    
    // this does not work because it uses the special `'static` lifetime.
    // which means _the entire program_. The main thread could finish and this
    // thread could still be running! In that case the reference to x would be invalid.
    // we can make this work by passing `move` in front of the closure,
    // effectively copying `x` into the closure's environment.
    
    // let normal = std::thread::spawn(|| dbg!(&x));
    // normal.join();
    
    // this works because it adopts the lifetime of `main`.
    let scoped = crossbeam::thread::scope(|s| {
        let child = s.spawn(|_| dbg!(&x));
        child.join()
    });
    dbg!(&scoped);
}