https://kaisery.github.io/trpl-zh-cn/ch16-01-threads.html
use std::thread; use std::time::Duration; fn main() { thread::spawn(|| { for i in 1..10 { println!("hi number {} from the spawned thread!", i); thread::sleep(Duration::from_millis(1)); } }); for i in 1..5 { println!("hi number {} from the main thread!", i); thread::sleep(Duration::from_millis(1)); } }
Compiling hello_world v0.1.0 (/data2/rust/thread) Finished dev [unoptimized + debuginfo] target(s) in 0.59s [root@bogon thread]# cargo run Finished dev [unoptimized + debuginfo] target(s) in 0.01s Running `target/debug/hello_world` hi number 1 from the main thread! hi number 1 from the spawned thread! hi number 2 from the main thread! hi number 2 from the spawned thread! hi number 3 from the main thread! hi number 3 from the spawned thread! hi number 4 from the main thread! hi number 4 from the spawned thread!
use std::thread; use std::time::Duration; fn main() { let handle = thread::spawn(|| { for i in 1..10 { println!("hi number {} from the spawned thread!", i); thread::sleep(Duration::from_millis(1)); } }); for i in 1..5 { println!("hi number {} from the main thread!", i); thread::sleep(Duration::from_millis(1)); } handle.join().unwrap(); }
[root@bogon thread1]# cargo build Compiling hello_world v0.1.0 (/data2/rust/thread1) Finished dev [unoptimized + debuginfo] target(s) in 0.58s [root@bogon thread1]# cargo run Finished dev [unoptimized + debuginfo] target(s) in 0.01s Running `target/debug/hello_world` hi number 1 from the main thread! hi number 1 from the spawned thread! hi number 2 from the main thread! hi number 2 from the spawned thread! hi number 3 from the main thread! hi number 3 from the spawned thread! hi number 4 from the main thread! hi number 4 from the spawned thread! hi number 5 from the spawned thread! hi number 6 from the spawned thread! hi number 7 from the spawned thread! hi number 8 from the spawned thread! hi number 9 from the spawned thread!
这两个线程仍然会交替执行，不过主线程会由于 handle.join() 调用会等待直到新建线程执行完毕。
不过让我们看看将 handle.join() 移动到 main 中 for 循环之前会发生什么，如下：
文件名: src/main.rs
use std::thread;
use std::time::Duration;
fn main() {
let handle = thread::spawn(|| {
for i in 1..10 {
println!("hi number {} from the spawned thread!", i);
thread::sleep(Duration::from_millis(1));
}
});
handle.join().unwrap();
for i in 1..5 {
println!("hi number {} from the main thread!", i);
thread::sleep(Duration::from_millis(1));
}
}
主线程会等待直到新建线程执行完毕之后才开始执行 for 循环，所以输出将不会交替出现，如下所示：
hi number 1 from the spawned thread!
hi number 2 from the spawned thread!
hi number 3 from the spawned thread!
hi number 4 from the spawned thread!
hi number 5 from the spawned thread!
hi number 6 from the spawned thread!
hi number 7 from the spawned thread!
hi number 8 from the spawned thread!
hi number 9 from the spawned thread!
hi number 1 from the main thread!
hi number 2 from the main thread!
hi number 3 from the main thread!
hi number 4 from the main thread!
诸如将 join 放置于何处这样的小细节，会影响线程是否同时运行。