Rust的并发编程以安全著称。本文介绍标准库的线程和通道，以及async/await异步编程。 ## 标准库线程 ```rust use std::thread; use std::time::Duration; fn main() { let handle = thread::spawn(|| { for i in 1..10 { println!("spawned thread: {}", i); thread::sleep(Duration::from_millis(1)); } }); for i in 1..5 { println!("main thread: {}", i); thread::sleep(Duration::from_millis(1)); } handle.join().unwrap(); } ``` ## 通道（Channel） ```rust use std::sync::mpsc; use std::thread; fn main() { let (tx, rx) = mpsc::channel(); thread::spawn(move || { let vals = vec![ String::from("hi"), String::from("from"), String::from("the"), String::from("thread"), ]; for val in vals { tx.send(val).unwrap(); } }); for received in rx { println!("Got: {}", received); } } ``` ## async/await ```rust use tokio; #[tokio::main] async fn main() { let handle = tokio::spawn(async { println!("hello from tokio task"); 42 }); let result = handle.await.unwrap(); println!("Result: {}", result); } ``` ## Send与Sync - Send：值可以安全地转移到另一个线程 - Sync：值可以安全地被多个线程引用 大多数类型自动实现这两个trait。Rc不实现Send（用Arc替代），RefCell不实现Sync（用Mutex替代）。 Rust的类型系统在编译期就防止了数据竞争，这是其他语言难以做到的。