windows - 了解MsgWaitForMultipleObjects

我有一个主要的gui线程，我希望对用户操作保持响应，例如，移动对话框，调整大小等，同时我有一个后台线程来执行某些任务。过去，我在等待后台线程完成的同时使用带有超时的WaitForSingleObject来处理gui事件。最近，我读到有关MsgWaitForMultipleObjects的文章，该文章似乎正在解决我的清理问题。

有人可以告诉我以下代码中的错误以及我在哪里出错吗？当我单击该按钮以启动线程时，gui没有响应。我制作了一个对话框应用程序，该应用程序具有在主ui线程上播放的avi。我有一个按钮来启动线程，并使用MsgWaitForMultipleObjects等待线程句柄，但允许处理所有消息，最终在线程完成/发出信号时中断。

谢谢。

UINT MyThreadProc( LPVOID pParam )
{
    ThreadData* pObject = (ThreadData*)pParam;

    if (pObject == NULL ||
        !pObject->IsKindOf(RUNTIME_CLASS(ThreadData)))
    return 1;

    // Do some processing.
    int x = 0;
    while (x++ < 5000)
    {
        for (int i=0; i<50000; i++)
            double sum = sqrt((double)i+1) * sqrt((double)i+2);
    }

    return 0;
}

按钮处理程序

void Cmsgwait_demoDlg::OnBnClickedBtnStartThread()
{
    m_pThreadData = new ThreadData;
    CWinThread* pWorkThread = AfxBeginThread(MyThreadProc, m_pThreadData);

    m_status.SetWindowText("Status: Waiting for thread to complete.");

    HANDLE handles[] = { pWorkThread->m_hThread };
    DWORD ret = 0;

    do
    {
        ret = MsgWaitForMultipleObjects(1, handles, FALSE, INFINITE, QS_ALLINPUT);
        if (ret == WAIT_OBJECT_0)
        {
            m_status.SetWindowText("Status: Thread completed.");
        }
        else if (WAIT_IO_COMPLETION)
        {
            m_status.SetWindowText("Status: User mode APC queued.");
        }
        else if (WAIT_FAILED)
        {
            m_status.SetWindowText("Status: Wait failed");
        }
    }
    while (ret != WAIT_OBJECT_0 && ret != WAIT_FAILED);
}

最佳答案

您不处理UI线程的传入消息，请使用look at Raymond's blog(另请参见here)作为示例。

  while (true) {
    switch (MsgWaitForMultipleObjects(1, &h,
                         FALSE, INFINITE, QS_ALLINPUT)) {
    case WAIT_OBJECT_0:
      DoSomethingWith(h); // event has been signalled
      break;
    case WAIT_OBJECT_0+1:
      // we have a message - peek and dispatch it
      while (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)) {
        // TODO:  must handle WM_QUIT; see Raymond's blog for details
        TranslateMessage(&msg);
        DispatchMessage(&msg);
      }
      break;
    default:
      return FALSE; // unexpected failure
    }
  }

关于windows - 了解MsgWaitForMultipleObjects，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/1461378/