FatalExit 0x0001 Possible If WM_CTLCOLOR Used Improperly

The information in this article applies to:

• Microsoft Windows Software Development Kit (SDK) for Windows versions 3.1 and 3.0

SUMMARY

An application can change the colors of a dialog box by creating a brush of the desired color and processing the WM_CTLCOLOR message to return a handle to the brush. If the brush is not a stock object, the application should create the brush before the dialog box is displayed and store its handle in a global or static variable. Do not use the following code in a dialog box procedure:

   case WM_CTLCOLOR:  // Create green edit fields
      if (HIWORD(lParam) == CTLCOLOR_EDIT)
         return CreateSolidBrush(RGB(0, 255, 0));
      break;

MORE INFORMATION

To avoid this error, modify the application to call the CreateSolidBrush function once, either outside the application's message loop or during the processing of the WM_CREATE message. Store the returned brush handle in a global or static variable. An advantage of this method is that the brush can be used in any part of the application without consuming any additional system resources.

The following code provides a skeleton for the WinMain procedure and for the dialog procedure to implement this method:

// WinMain

WinMain (...) {

   // Register window class and create window

   hBrushGreen = CreateSolidBrush(RGB(0, 255, 0));

   while (GetMessage(...))
     {
     TranslateMessage(...);
     DispatchMessage(...);
     }

   DeleteObject(hBrushGreen);
   return msg.wparam;

// Dialog box procedure
   case WM_CTLCOLOR: // Green edit fields
      if (HIWORD(lParam) == CTLCOLOR_EDIT)
         return hBrushGreen;
      break;