How to know no message in WindowProc callback function?

[cedricvictor]

Dear all: I use two global variables UINT g_PreUsedSize and g_CurUsedSize in WindowProc callback function. When I touch on my device, I will get WM_INPUT message continuous in WindowProc callback function, and get a result->active_touch_count, and set it to g_CurUsedSize. When I did not touch on my device, I wanna set 0 to g_CurUsedSize.

LRESULT CALLBACK WindowProc (HWND window_handle, UINT message, WPARAM w_param, LPARAM l_param)
{
LRESULT result (0);

switch (message)
{
case WM_DESTROY:
PostQuitMessage (0);
break;

  case WM\_SIZE:
     {
        switch (w\_param)
        {
           case SIZE\_MAXIMIZED:
           case SIZE\_RESTORED:
           {
               window\_width = (float)(LOWORD (l\_param));
               window\_height = (float)(HIWORD (l\_param));
           }
           break;
        }
     }
     break;

    case WM\_INPUT:
    {		
        UINT data\_size (0);
        GetRawInputData ((HRAWINPUT)l\_param, RID\_INPUT,NULL, &data\_size, sizeof (RAWINPUTHEADER));
        
        vector data;
        data.resize (data\_size);

        if (GetRawInputData ((HRAWINPUT)l\_param, RID\_INPUT, &data \[0\], &data\_size, sizeof(RAWINPUTHEADER)) != data\_size)
        {
            OutputDebugString(TEXT("GetRawInputData does not return correct size !\\n")); 
            break;
        }
          
        RAWINPUT\* raw = (RAWINPUT\*)(&data \[0\]);
       
        if (raw->header.dwType == RIM\_TYPEHID) 
        {
            RID\_DEVICE\_INFO device\_info;
       UINT info\_size = sizeof(RIDI\_DEVICEINFO);
       GetRawInputDeviceInfo ( raw->header.hDevice, RIDI\_DEVICEINFO, (LPVOID)&device\_info, &info\_size);
			   
       if(device\_info.hid.dwVendorId = 0x0457)
       {
 	           DigitizerData\* result = (DigitizerData\*)(raw->data.hid.bRawData);
				
                g\_CurUsedSize = result->active\_touch\_count;	
			
     	           BOOL bGot = FALSE;

	  if(g\_CurUsedSize <= 5)
	  {
	      if(g\_PreUsedSize <  g\_CurUsedSize)
	      {
	        PlaySound(TEXT("C:\\\\default.wav"),NULL, SND\_FILENAME|SND\_ASYNC );
              }
          }
	  bGot = TRUE;
       }
   }

   if(bGot)
   {
          g\_PreUsedSize =  g\_CurUsedSize;
   }
     }				 
 }
 result = DefWindowProc (window\_handle, message, w\_param, l\_param);

}

[Lost User]

cedricvictor wrote:

How do I know my device send no data in WindowProc, if I did not touch?

You cannot test for something not happening, only for things that do happen. You could use a flag in your WindowProc, which starts as false and gets set to true if you receive a touch input. At the end of the routine if the flag is still false then set your value to zero.