multithreading - 防止应用程序在所有线程完成之前关闭

Question

这就是我得到的:

extern crate time;

use std::thread;

fn main() {

    let start = time::get_time();
    println!("Starting application");
    do_stuff();
    println!("Total {:?}", time::get_time() - start);

}

fn do_stuff() {

    for i in 0..4i32 {
        thread::spawn(move || {
            thread::sleep_ms(1);
            println!("doing stuff {:?}", i);
        });
    }

}

出于某种原因，我不熟悉应用程序不等待函数 do_stuff() 中的线程完成并关闭。所以这是我得到的输出:

Starting application
Total Duration { secs: 0, nanos: 808482 }

而不是像

Starting application
doing stuff 1
doing stuff 2
doing stuff 3
doing stuff 4
Total Duration { secs: 0, nanos: 808482 }

即使线程未返回任何内容，我如何让应用程序等待线程完成？

Answer 1

spawn 函数返回一个JoinHandle。您可以将所有句柄收集到一个向量中，然后对它们调用 join:

extern crate time;

use std::thread;

fn main() {

    let start = time::get_time();
    println!("Starting application");
    do_stuff();
    println!("Total {:?}", time::get_time() - start);
}

fn do_stuff() {
    let handles: Vec<_> = (0..4).map(|i| {
        thread::spawn(move || {
            thread::sleep_ms(1);
            println!("doing stuff {:?}", i);
        })
    }).collect();

    for h in handles {
        h.join().unwrap();
    }
}