Microsoft KB Archive/75338

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Determining Windows Version, Mode from MS-DOS App

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Q75338

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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

Keywords : kb16bitonly

Issue type :

Technology : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK310