dropwait.rs

use std::sync::mpsc;
use std::{thread, time};

struct Guard {
    tx: mpsc::SyncSender<bool>,
}

impl Drop for Guard {
    fn drop(&mut self) {
        println!("in drop about to send");
        self.tx.send(true);
        println!("in drop send finished");
    }
}

fn main() {
    let (tx, rx) = mpsc::sync_channel::<bool>(0);
    let guard = Guard { tx };
    thread::spawn(move || {
        println!("thread sleeping");
        thread::sleep(time::Duration::from_secs(5));
        println!("thread sleep finished, dropping guard");
        drop(guard);
    });
    println!("main thread about to wait");
    rx.recv();
    println!("main thread finished");
}