Microsoft KB Archive/69895

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PRB: Activating Full-Screen DOS App from Icon in Enhanced Mode


The information in this article applies to:

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


In Microsoft Windows enhanced mode, when an application calls the OpenIcon or ShowWindows functions to activate a full-screen MS-DOS application from an icon, the activation fails. These functions perform as documented in real and standard mode.


To avoid this problem, simulate the result of an ALT+TAB key combination on the MS-DOS application icon: Send a WM_ACTIVATE message to the MS-DOS application, and then specify its handle in a call to ShowWindow function. For example:

   SendMessage(hDOSApp, WM_ACTIVATE, 1, MAKELONG(hDOSApp, TRUE));
   ShowWindow(hDOSApp, SW_SHOWNORMAL); 

When the application sends the WM_ACTIVATE message, wParam is set to 1 because the application is being invoked by simulating the keyboard. The high-order word of lParam is set to TRUE (non-zero) because the MS-DOS application is represented by an icon.

The method works in all three Windows modes for windowed and full- screen MS-DOS applications.

Additional query words: 3.00 3.10

Keywords :
Issue type :
Technology : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK300 kbWinSDK310

Last Reviewed: November 6, 1999
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