multithreading - 了解 Rust channel 。 `send` 如何工作？

Question

我正在阅读 this example关于线程通信:

use std::sync::mpsc::{Sender, Receiver};
use std::sync::mpsc;
use std::thread;

static NTHREADS: i32 = 3;

fn main() {
    // Channels have two endpoints: the `Sender<T>` and the `Receiver<T>`,
    // where `T` is the type of the message to be transferred
    // (type annotation is superfluous)
    let (tx, rx): (Sender<i32>, Receiver<i32>) = mpsc::channel();
    let mut children = Vec::new();

    for id in 0..NTHREADS {
        // The sender endpoint can be copied
        let thread_tx = tx.clone();

        // Each thread will send its id via the channel
        let child = thread::spawn(move || {
            // The thread takes ownership over `thread_tx`
            // Each thread queues a message in the channel
            thread_tx.send(id).unwrap();

            // Sending is a non-blocking operation, the thread will continue
            // immediately after sending its message
            println!("thread {} finished", id);
        });

        children.push(child);
    }

    // Here, all the messages are collected
    let mut ids = Vec::with_capacity(NTHREADS as usize);
    for _ in 0..NTHREADS {
        // The `recv` method picks a message from the channel
        // `recv` will block the current thread if there are no messages available
        ids.push(rx.recv());
    }

    // Wait for the threads to complete any remaining work
    for child in children {
        child.join().expect("oops! the child thread panicked");
    }

    // Show the order in which the messages were sent
    println!("{:?}", ids);
}

我对这两行有问题:

thread_tx.send(id).unwrap();
println!("thread {} finished", id);

怎么样 send工作？它发送副本？这是我仍然可以使用 id 的唯一方法在 send 中使用后，不是吗？

如果我是正确的，那么如何以非复制模式发送？我可以以“自己的方式”发送，即发送功能现在拥有它，但我无法再次使用它。我也可以借用的方式发送，作为引用，但除非另一个线程释放它，否则我无法再次使用它。

Answer 1

How does send work? It sends a copy? That's the only way I can still use id after using it in send, isn't it?

发送发送你给它的任何东西。这里它发送一个副本，因为 id是 i32，即 Copy ，但它本质上并不关心，

The documentation of the Copy trait has some explanations .还有 this old answer它提供了一个较短(但不那么广泛)的解释。