MS-DOS-Based Application Characteristics Under Windows

The information in this article applies to:

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

SUMMARY

This article discusses the mechanism that the Microsoft Windows graphical environment uses to run an MS-DOS (non-Windows) application.

MORE INFORMATION

In the Window environment, each MS-DOS-based application runs has a Windows-based application to act as its agent. When the MS-DOS-based application is running in a window under enhanced mode Windows, and the MS- DOS-based application makes a call to the display hardware, the agent intercepts the call and places the character into its window. To the MS-DOS-based application, the agent acts as a virtual copy of the display hardware.

NOTE: The Windows agent does not manage the display; it simply renders the MS-DOS-based application's display into a window.

To determine if an application is an MS-DOS-based application, check the application's name to see if it matches the name of the MS-DOS-based application agent. The module name of the MS-DOS-based application agent is WINOLDAP. The following code fragment performs this check:

   BOOL IsThisWOAWindow(HWND hWnd)
   {
      BOOL IsWOA;
      HANDLE hModWOA;

      IsWOA = FALSE;
      if (hModWOA = GetModuleHandle("WINOLDAP"))
         {
         if (hModWOA == (HANDLE)(GetClassWord(hWnd, GCW_HMODULE)))
            {
            IsWOA = TRUE;
            }
         }
      return IsWOA;
   }