multithreading - rust tokio::spawn 在 mutexguard 之后等待

Question

锁定互斥锁后我无法放置异步函数。示例 2 有效，而示例 1 则有效。这是为什么。我已经处理掉了 temp，为什么它会导致问题

let temp = Arc::new(Mutex::new(0));
tokio::spawn(async move {
        let temp = temp.lock().unwrap();
        drop(temp);
        async_func().await
    });

tokio::spawn(async move {
        async_func().await;
        let temp = temp.lock().unwrap();
        drop(temp);
    });

future cannot be sent between threads safely future created by async block is not `Send` Help: within `impl futures_util::Future<Output = ()>`, the trait `std::marker::Send` is not implemented for `std::sync::MutexGuard<'_, i32>` Note: future is not `Send` as this value is used across an await Note: required by a bound in `tokio::spawn

Answer 1

您可以使用 block 代替drop。

let handle = tokio::spawn(async move {
    {
        let temp = temp.lock().unwrap();
    }
    async_func().await
});

这是一个错误( 57478 、 87309 )，因此 drop 版本将在 97331 时运行。已合并。