使用 await 命名 Mutex [英] Named Mutex with await

问题描述

因此我不能在 async 中使用线程仿射锁 - 在运行多个进程时如何保护我的资源?

Hence I can't use thread-affine locks with async - how can I guard my resources when running multiple processes?

例如我有两个进程使用下面的任务:

For example I've two processes that use a Task below:

 public async Task<bool> MutexWithAsync()
 {
     using (Mutex myMutex = new Mutex(false, "My mutex Name"))
     {
         try
         {
             myMutex.WaitOne();
             await DoSomething();
             return true;
         }
         catch { return false; }
         finally { myMutex.ReleaseMutex(); }
     }
 }

如果 Mutex 保护的方法是同步的，那么上面的代码可以工作，但是使用 async 我会得到:

If the method guarded by a Mutex is synchronous then above code will work but with async I will get:

从未同步的代码块调用对象同步方法.

Object synchronization method was called from an unsynchronized block of code.

那么 Named Mutex 对异步代码没用吗?

So is Named Mutex useless with asynchronous code?

推荐答案

您必须确保在某个线程上一致地访问互斥锁.您可以通过多种方式做到这一点:

You must ensure that mutex is being accessed consistently on a certain thread. You could do that in a number of ways:

1. 不要在持有互斥锁的临界区使用 await
2. 在只有一个线程的 TaskScheduler 上调用互斥锁

1. Do not use await in the critical section during which you hold the mutex
2. Invoke the mutex calls on a TaskScheduler that only has a single thread

可能看起来像这样:

await Task.Factory.StartNew(() => mutex.WaitOne(), myCustomTaskScheduler);

或者，您使用同步代码并将所有内容移至线程池.如果您只能访问 DoSomething 的异步版本，请考虑仅对其结果调用 Task.Wait.在这里，您会遇到一点点效率低下的问题.应该没问题.

Or, you use synchronous code and move everything to the thread-pool. If you only have access to an async version of DoSomething, consider just calling Task.Wait on its result. You'll suffer a minor inefficiency here. Probably fine.

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