c# - 当发出同步 I/O 调用时，当前线程 (C#) 的 ThreadState 是什么？

Question

以下是我的代码:

static int Main(string[] args)
{
    Thread current_thread = Thread.CurrentThread;

    new Thread(() => { var i = 0; while (++i > 0) { Thread.Sleep(100); Console.WriteLine("Thread: " + current_thread.ManagedThreadId + ", State: " + current_thread.ThreadState + ", I: " + i); } }).Start();

    while(true)
    {
        Console.WriteLine("Thread: " + Thread.CurrentThread.ManagedThreadId + ", State: " + Thread.CurrentThread.ThreadState);

        // creating a http request...
        // ...
        requst.GetResponseStream(); // this is the synchronous call 
    }
}

输出显示当前线程(主线程)的状态总是ThreadState.Running。那么，为什么，为什么不是 ThreadState.WaitSleepJoin？

GetResponseStream() 是同步的。在等待远程响应时，cpu 时间片可以(也应该)放弃给其他线程，对吗？ (如果我错了请纠正我)

非常感谢。

Answer 1

是的，它是 WaitSleepJoin。您的示例代码显然是不完整和错误的(例如，您没有启动新线程)，因此很难说出为什么您看不到正确的值。您是否总是为 GetResponseStream 创建新请求？

此代码显示了您的预期:

Thread current_thread = Thread.CurrentThread;

new Thread(() => 
{ 
  var i = 0; while (++i > 0) 
  { 
    if ((current_thread.ThreadState & System.Threading.ThreadState.WaitSleepJoin) > 0) 
      Console.WriteLine("Thread: " + current_thread.ManagedThreadId 
       + ", State: " + current_thread.ThreadState + ", I: " + i); 
  } 
}
).Start();

while(true)
{
    Console.WriteLine("Thread: " + Thread.CurrentThread.ManagedThreadId 
      + ", State: " + Thread.CurrentThread.ThreadState);

    var request = HttpWebRequest.CreateHttp("http://www.google.com/");

    using (var response = request.GetResponse())
    {
        using (var stream = response.GetResponseStream())
        {
            stream.Read(new byte[2048], 0, 2048);
        }
    } 
}

棘手的部分是它不会在 WaitSleepJoin 状态中花费大量时间。