SetTimer在无窗口和有窗口线程的使用 . .

今天犯了一个粗心的错误,在无窗口线程中,SetTimer中设置计时器ID,而WM_TIMER消息响应函数中得到的计时器ID却不是之前设置的计时器ID.

 

  1. // 111902.cpp : Defines the entry point for the console application.   
  2. //   
  3. //#include "stdafx.h"   
  4. #include "stdio.h"   
  5. #include "windows.h"   
  6. BOOL DispatchThreadMessage(MSG* pMsg);  
  7. VOID CALLBACK OnTimerProc(HWND hwnd,UINT uMsg,UINT_PTR idEvent,DWORD dwTime);  
  8. int main(int argc, char* argv[])  
  9. {  
  10.     printf("Hello World!\n");  
  11.     ::SetTimer(NULL,45,1000,OnTimerProc);  
  12.     MSG msg;  
  13.     while (GetMessage(&msg, 0, 0, 0) > 0)  
  14.     {  
  15.         if (msg.hwnd == NULL && DispatchThreadMessage(&msg))  
  16.             continue;  
  17.         TranslateMessage(&msg);  
  18.         DispatchMessage(&msg);  
  19.     }  
  20.     return 0;  
  21. }  
  22.   
  23. BOOL DispatchThreadMessage(MSG* pMsg)  
  24. {  
  25.     if(pMsg->message == 0x0113)  
  26.     {  
  27.         printf("DispatchThreadMessage: %6d\n",pMsg->wParam);  
  28.         return false;         
  29.     }  
  30.     return false;  
  31. }   
  32. VOID CALLBACK OnTimerProc(HWND hwnd,UINT uMsg,UINT_PTR idEvent,DWORD dwTime)  
  33. {  
  34.     printf("OnTimerProc: %6d\n",idEvent);  
  35. }  

 

 

对应计时器ID的输出的是一个随机数字.

 

原来在msdn中

nIDEvent
[in] Specifies a nonzero timer identifier. If the hWnd parameter is NULL, and the nIDEvent does not match an existing timer then it is ignored and a new timer ID is generated. If the hWnd parameter is not NULL and the window specified by hWnd already has a timer with the value nIDEvent , then the existing timer is replaced by the new timer. When SetTimer replaces a timer, the timer is reset. Therefore, a message will be sent after the current time-out value elapses, but the previously set time-out value is ignored. If the call is not intended to replace an existing timer, nIDEvent should be 0 if the hWnd is NULL.

注:只有当hWnd参数为非空时,计时器的ID为设置的 nIDEvent,  否则系统为你自动生成一个计时器ID,可由返回时值获取.

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