如何在非Windows线程构建定时器回掉？

Question

MFC程序，自己创建了一个线程A，非Windows线程。

现在需要实现一个定时器，由线程A启动，回调函数被调用时做一些处理。

现在用SetTimer/KillTimer组合，发现回掉函数没有执行，后来查询一下，似乎SetTimer/KillTimer回向线程发送一个WM_TIMER消息，因此必须是Window线程，必须有消息队列。但是线程A是普通线程，没有线程队列，收不到WM_TIMER消息。

后来想用等待时钟，WaitTimer。用CreateWaitableTimer/SetWaitableTimer，设置回掉函数。发现还是没法触发回掉函数。

自己写了一个列子，在main主函数中调用SleepEx（INFINITE,  TRUE); 的话，回掉函数可以调用。

如果把SleepEx替换成Sleep的话，回调函数就没触发。搞不懂什么原因，似乎SleepEx把线程状态置为阻塞？

我的线程A是一个主工作线程，不能阻塞或者SleepEx睡眠等待。这种情况下，如何利用异步回调函数？

#define UNICODE 1
#define _UNICODE 1
#pragma comment(lib, "user32.lib")

#include <windows.h>
#include <stdio.h>
#include <tchar.h>

#define _SECOND 10000000

typedef struct _MYDATA {
   TCHAR *szText;
   DWORD dwValue;
} MYDATA;

VOID CALLBACK TimerAPCProc(
   LPVOID lpArg,               // Data value
   DWORD dwTimerLowValue,      // Timer low value
   DWORD dwTimerHighValue )    // Timer high value

{
   // Formal parameters not used in this example.
   UNREFERENCED_PARAMETER(dwTimerLowValue);
   UNREFERENCED_PARAMETER(dwTimerHighValue);

   MYDATA *pMyData = (MYDATA *)lpArg;

   _tprintf( TEXT("Message: %s\nValue: %d\n\n"), pMyData->szText,
          pMyData->dwValue );
   MessageBeep(0);

}

int main( void ) 
{
   HANDLE          hTimer;
   BOOL            bSuccess;
   __int64         qwDueTime;
   LARGE_INTEGER   liDueTime;
   MYDATA          MyData;

   MyData.szText = TEXT("This is my data");
   MyData.dwValue = 100;

   hTimer = CreateWaitableTimer(
           NULL,                   // Default security attributes
           FALSE,                  // Create auto-reset timer
           TEXT("MyTimer"));       // Name of waitable timer
   if (hTimer != NULL)
   {
      __try 
      {
         // Create an integer that will be used to signal the timer 
         // 5 seconds from now.
         qwDueTime = -5 * _SECOND;

         // Copy the relative time into a LARGE_INTEGER.
         liDueTime.LowPart  = (DWORD) ( qwDueTime & 0xFFFFFFFF );
         liDueTime.HighPart = (LONG)  ( qwDueTime >> 32 );

         bSuccess = SetWaitableTimer(
            hTimer,           // Handle to the timer object
            &liDueTime,       // When timer will become signaled
            2000,             // Periodic timer interval of 2 seconds
            TimerAPCProc,     // Completion routine
            &MyData,          // Argument to the completion routine
            FALSE );          // Do not restore a suspended system

         if ( bSuccess ) 
         {
            for ( ; MyData.dwValue < 1000; MyData.dwValue += 100 ) 
            {
               SleepEx(
                  INFINITE,     // Wait forever
                  TRUE );       // Put thread in an alertable state
            }

         } 
         else 
         {
            printf("SetWaitableTimer failed with error %d\n", GetLastError());
         }

      } 
      __finally 
      {
         CloseHandle( hTimer );
      }
   } 
   else 
   {
      printf("CreateWaitableTimer failed with error %d\n", GetLastError());
   }

   return 0;
}

Answer 1

其实在工作线程中您可以设置消息循环SetTimer/KillTimer就可以正常工作了。

#include <Windows.h>
#include <iostream>
#include <process.h>
using namespace std;

VOID CALLBACK TimerProc(
	_In_ HWND     hwnd,
	_In_ UINT     uMsg,
	_In_ UINT_PTR idEvent,
	_In_ DWORD    dwTime
)
{
	static size_t nCount = 0;
	cout << nCount++  << " : Timeout" << endl;
}

unsigned __stdcall ThreadProc(void* lParam)
{
	SetTimer(NULL, 1, 1000, TimerProc);
	MSG msg;
	while (GetMessage(&msg, NULL, 0, 0))
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}
	KillTimer(NULL, 1);
	return 0;
}

int main()
{
	HANDLE hThread = (HANDLE)_beginthreadex(NULL, 0, ThreadProc, NULL, 0, NULL);
	WaitForSingleObject(hThread, INFINITE);
	CloseHandle(hThread);

    return 0;
}

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Visual C++ enthusiast, like network programming and driver development. At present is being engaged in the WinCE/Windows Mobile platform embedded development.

Answer 2

如果不想在工作线程中设置消息循环也可以，用内核对象来做WaitForSingleObject的操作也可以达到SetTimer的效果。

// 线程函数中
unsigned __stdcall ThreadProc(void* lParam)
{
	while (WAIT_TIMEOUT == WaitForSingleObject(hEvent, dwTimeout))
	{
		// TODO:
	}
	return 0;
}

---

Visual C++ enthusiast, like network programming and driver development. At present is being engaged in the WinCE/Windows Mobile platform embedded development.

Answer 3

DWORD WINAPI SleepEx(
  _In_ DWORD dwMilliseconds,
  _In_ BOOL  bAlertable
);

这个与SleepEx的第二个参数bAlertable有关，如果将其设置为FALSE，您看看回调函数还能正常响应吗？将第二个参数设置为FALSE，实际就与Sleep调用一样了。
详细说明请参考MSDN文档。

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Visual C++ enthusiast, like network programming and driver development. At present is being engaged in the WinCE/Windows Mobile platform embedded development.