Q75338: Determining Windows Version, Mode from MS-DOS App

Article: Q75338
Product(s): Microsoft Windows Software Development Kit
Version(s): WINDOWS:3.1
Operating System(s): 
Keyword(s): kb16bitonly
Last Modified: 06-NOV-1999

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The information in this article applies to:

- Microsoft Windows Software Development Kit (SDK) 3.1 
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SUMMARY
=======

The following assembly language code fragment can be used in an MS-DOS- based
application to determine if it is running in a Windows MS-DOS window, and if so,
which version and mode of Windows is running.

  test_win proc near

  ; check for Windows 3.1

      mov     ax,160ah                ; WIN31CHECK
      int     2fh                     ; check if running under Win 3.1.
      or      ax,ax
      jz      RunningUnderWin31       ; can check if running in standard
                                      ; or enhanced mode

  ; check for Windows 3.0 enhanced mode

      mov     ax,1600h                ; WIN386CHECK
      int     2fh
      test    al,7fh
      jnz     RunningUnderWin30Enh    ; enhanced mode

  ; check for 3.0 WINOLDAP

      mov     ax,4680h                ; IS_WINOLDAP_ACTIVE
      int     2fh
      or      ax,ax                   ; running under 3.0 derivative?
      jnz     NotRunningUnderWin

  ; rule out MS-DOS 5.0 task switcher

      mov     ax,4b02h                ; detect switcher
      push    bx
      push    es
      push    di
      xor     bx,bx
      mov     di,bx
      mov     es,bx
      int     2fh
      pop     di
      pop     es
      pop     bx
      or      ax,ax
      jz      NotRunningUnderWin      ; MS-DOS 5.0 task switcher found

  ; check for standard mode Windows 3.0

      mov     ax,1605h                ; PMODE_START
      int     2fh
      cmp     cx,-1
      jz      RunningUnderWin30Std

  ; check for real mode Windows 3.0

      mov     ax,1606h                ; PMODE_STOP
      int     2fh                     ; in case someone is counting
      ; Real mode Windows 3.0 is running
      jmp     NotRunningUnderWin

RunningUnderWin30Std:

      ; Standard mode Windows 3.0 is running
      jmp     NotRunningUnderWin

RunningUnderWin31:

      ; At this point: CX == 3 means Windows 3.1 enhanced mode
      ;                CX == 2 means Windows 3.1 standard mode
      jmp     NotRunningUnderWin

RunningUnderWin30Enh:

      ; Enhanced mode Windows 3.0 is running

NotRunningUnderWin:

          ret

  test_win endp

MORE INFORMATION
================

Applications for Windows should use the GetWinFlags() function to determine
which version of Windows is running. For more information, please see the
following article in the Microsoft Knowledge Base:

  Q131371 Determining System Version from a Windows-Based Application

Additional query words: 3.10

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Keywords          : kb16bitonly 
Technology        : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK310
Version           : WINDOWS:3.1

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