How to detect true Windows version?

Question

I know I can call the GetVersionEx Win32 API function to retrieve Windows version. In most cases returned value reflects the version of my Windows, but sometimes that is not so.

If a user runs my application under the compatibility layer, then GetVersionEx won't be reporting the real version but the version enforced by the compatibility layer. For example, if I'm running Vista and execute my program in "Windows NT 4" compatibility mode, GetVersionEx won't return version 6.0 but 4.0.

Is there a way to bypass this behaviour and get true Windows version?

Answer 1

How about obtaining the version of a system file?

The best file would be kernel32.dll, located in %WINDIR%\System32\kernel32.dll.

There are APIs to obtain the file version. eg: I'm using Windows XP -> "5.1.2600.5512 (xpsp.080413-2111)"

Answer 2

The best approach I know is to check if specific API is exported from some DLL. Each new Windows version adds new functions and by checking the existance of those functions one can tell which OS the application is running on. For example, Vista exports GetLocaleInfoEx from kernel32.dll while previous Windowses didn't.

To cut the long story short, here is one such list containing only exports from kernel32.dll.

> *function: implemented in*  
> GetLocaleInfoEx:       Vista  
> GetLargePageMinimum:   Vista, Server 2003  
GetDLLDirectory:         Vista, Server 2003, XP SP1  
GetNativeSystemInfo:     Vista, Server 2003, XP SP1, XP  
ReplaceFile:             Vista, Server 2003, XP SP1, XP, 2000  
OpenThread:              Vista, Server 2003, XP SP1, XP, 2000, ME  
GetThreadPriorityBoost:  Vista, Server 2003, XP SP1, XP, 2000,     NT 4  
IsDebuggerPresent:       Vista, Server 2003, XP SP1, XP, 2000, ME, NT 4, 98   
GetDiskFreeSpaceEx:      Vista, Server 2003, XP SP1, XP, 2000, ME, NT 4, 98, 95 OSR2  
ConnectNamedPipe:        Vista, Server 2003, XP SP1, XP, 2000,     NT 4,                 NT 3  
Beep:                    Vista, Server 2003, XP SP1, XP, 2000, ME,       98, 95 OSR2, 95  

Writing the function to determine the real OS version is simple; just proceed from newest OS to oldest and use GetProcAddress to check exported APIs. Implementing this in any language should be trivial.

The following code in Delphi was extracted from the free DSiWin32 library):

TDSiWindowsVersion = (wvUnknown, wvWin31, wvWin95, wvWin95OSR2, wvWin98,
  wvWin98SE, wvWinME, wvWin9x, wvWinNT3, wvWinNT4, wvWin2000, wvWinXP,
  wvWinNT, wvWinServer2003, wvWinVista);

function DSiGetWindowsVersion: TDSiWindowsVersion;
var
  versionInfo: TOSVersionInfo;
begin
  versionInfo.dwOSVersionInfoSize := SizeOf(versionInfo);
  GetVersionEx(versionInfo);
  Result := wvUnknown;
  case versionInfo.dwPlatformID of
    VER_PLATFORM_WIN32s: Result := wvWin31;
    VER_PLATFORM_WIN32_WINDOWS:
      case versionInfo.dwMinorVersion of
        0:
          if Trim(versionInfo.szCSDVersion[1]) = 'B' then
            Result := wvWin95OSR2
          else
            Result := wvWin95;
        10:
          if Trim(versionInfo.szCSDVersion[1]) = 'A' then
            Result := wvWin98SE
          else
            Result := wvWin98;
        90:
          if (versionInfo.dwBuildNumber = 73010104) then
             Result := wvWinME;
           else
             Result := wvWin9x;
      end; //case versionInfo.dwMinorVersion
    VER_PLATFORM_WIN32_NT:
      case versionInfo.dwMajorVersion of
        3: Result := wvWinNT3;
        4: Result := wvWinNT4;
        5:
          case versionInfo.dwMinorVersion of
            0: Result := wvWin2000;
            1: Result := wvWinXP;
            2: Result := wvWinServer2003;
            else Result := wvWinNT
          end; //case versionInfo.dwMinorVersion
        6: Result := wvWinVista;
      end; //case versionInfo.dwMajorVersion
    end; //versionInfo.dwPlatformID
end; { DSiGetWindowsVersion }

function DSiGetTrueWindowsVersion: TDSiWindowsVersion;

  function ExportsAPI(module: HMODULE; const apiName: string): boolean;
  begin
    Result := GetProcAddress(module, PChar(apiName)) <> nil;
  end; { ExportsAPI }

var
  hKernel32: HMODULE;

begin { DSiGetTrueWindowsVersion }
  hKernel32 := GetModuleHandle('kernel32');
  Win32Check(hKernel32 <> 0);
  if ExportsAPI(hKernel32, 'GetLocaleInfoEx') then
    Result := wvWinVista
  else if ExportsAPI(hKernel32, 'GetLargePageMinimum') then
    Result := wvWinServer2003
  else if ExportsAPI(hKernel32, 'GetNativeSystemInfo') then
    Result := wvWinXP
  else if ExportsAPI(hKernel32, 'ReplaceFile') then
    Result := wvWin2000
  else if ExportsAPI(hKernel32, 'OpenThread') then
    Result := wvWinME
  else if ExportsAPI(hKernel32, 'GetThreadPriorityBoost') then
    Result := wvWinNT4
  else if ExportsAPI(hKernel32, 'IsDebuggerPresent') then  //is also in NT4!
    Result := wvWin98
  else if ExportsAPI(hKernel32, 'GetDiskFreeSpaceEx') then  //is also in NT4!
    Result := wvWin95OSR2
  else if ExportsAPI(hKernel32, 'ConnectNamedPipe') then
    Result := wvWinNT3
  else if ExportsAPI(hKernel32, 'Beep') then
    Result := wvWin95
  else // we have no idea
    Result := DSiGetWindowsVersion;
end; { DSiGetTrueWindowsVersion }

--- updated 2009-10-09

It turns out that it gets very hard to do an "undocumented" OS detection on Vista SP1 and higher. A look at the API changes shows that all Windows 2008 functions are also implemented in Vista SP1 and that all Windows 7 functions are also implemented in Windows 2008 R2. Too bad :(

--- end of update

FWIW, this is a problem I encountered in practice. We (the company I work for) have a program that was not really Vista-ready when Vista was released (and some weeks after that ...). It was not working under the compatibility layer either. (Some DirectX problems. Don't ask.)

We didn't want too-smart-for-their-own-good users to run this app on Vista at all - compatibility mode or not - so I had to find a solution (a guy smarter than me pointed me into right direction; the stuff above is not my brainchild). Now I'm posting it for your pleasure and to help all poor souls that will have to solve this problem in the future. Google, please index this article!

If you have a better solution (or an upgrade and/or fix for mine), please post an answer here ...

Answer 3

real version store on PEB block of process information.

Sample for Win32 app (Delphi Code)

unit RealWindowsVerUnit;

interface

uses
  Windows;

var
  //Real version Windows
  Win32MajorVersionReal: Integer;
  Win32MinorVersionReal: Integer;

implementation

type
  PPEB=^PEB;
  PEB = record
    InheritedAddressSpace: Boolean;
    ReadImageFileExecOptions: Boolean;
    BeingDebugged: Boolean;
    Spare: Boolean;
    Mutant: Cardinal;
    ImageBaseAddress: Pointer;
    LoaderData: Pointer;
    ProcessParameters: Pointer; //PRTL_USER_PROCESS_PARAMETERS;
    SubSystemData: Pointer;
    ProcessHeap: Pointer;
    FastPebLock: Pointer;
    FastPebLockRoutine: Pointer;
    FastPebUnlockRoutine: Pointer;
    EnvironmentUpdateCount: Cardinal;
    KernelCallbackTable: PPointer;
    EventLogSection: Pointer;
    EventLog: Pointer;
    FreeList: Pointer; //PPEB_FREE_BLOCK;
    TlsExpansionCounter: Cardinal;
    TlsBitmap: Pointer;
    TlsBitmapBits: array[0..1] of Cardinal;
    ReadOnlySharedMemoryBase: Pointer;
    ReadOnlySharedMemoryHeap: Pointer;
    ReadOnlyStaticServerData: PPointer;
    AnsiCodePageData: Pointer;
    OemCodePageData: Pointer;
    UnicodeCaseTableData: Pointer;
    NumberOfProcessors: Cardinal;
    NtGlobalFlag: Cardinal;
    Spare2: array[0..3] of Byte;
    CriticalSectionTimeout: LARGE_INTEGER;
    HeapSegmentReserve: Cardinal;
    HeapSegmentCommit: Cardinal;
    HeapDeCommitTotalFreeThreshold: Cardinal;
    HeapDeCommitFreeBlockThreshold: Cardinal;
    NumberOfHeaps: Cardinal;
    MaximumNumberOfHeaps: Cardinal;
    ProcessHeaps: Pointer;
    GdiSharedHandleTable: Pointer;
    ProcessStarterHelper: Pointer;
    GdiDCAttributeList: Pointer;
    LoaderLock: Pointer;
    OSMajorVersion: Cardinal;
    OSMinorVersion: Cardinal;
    OSBuildNumber: Cardinal;
    OSPlatformId: Cardinal;
    ImageSubSystem: Cardinal;
    ImageSubSystemMajorVersion: Cardinal;
    ImageSubSystemMinorVersion: Cardinal;
    GdiHandleBuffer: array [0..33] of Cardinal;
    PostProcessInitRoutine: Cardinal;
    TlsExpansionBitmap: Cardinal;
    TlsExpansionBitmapBits: array [0..127] of Byte;
    SessionId: Cardinal;
  end;

//Get PEB block current win32 process
function GetPDB: PPEB; stdcall;
asm
  MOV EAX, DWORD PTR FS:[30h]
end;

initialization
  //Detect true windows wersion
  Win32MajorVersionReal := GetPDB^.OSMajorVersion;
  Win32MinorVersionReal := GetPDB^.OSMinorVersion;
end.

Answer 4

Note: Gabr is asking about an approach that can bypass the limitations of GetVersionEx. JCL code uses GetVersionEx, and is thus subject to compatibility layer. This information is for people who don't need to bypass the compatibility layer, only.

Using the Jedi JCL, you can add unit JclSysInfo, and call function GetWindowsVersion. It returns an enumerated type TWindowsVersion.

Currently JCL contains all shipped windows versions, and gets changed each time Microsoft ships a new version of Windows in a box:

  TWindowsVersion =
   (wvUnknown, wvWin95, wvWin95OSR2, wvWin98, wvWin98SE, wvWinME,
    wvWinNT31, wvWinNT35, wvWinNT351, wvWinNT4, wvWin2000, wvWinXP,
    wvWin2003, wvWinXP64, wvWin2003R2, wvWinVista, wvWinServer2008,
    wvWin7, wvWinServer2008R2);

If you want to know if you're running 64-bit windows 7 instead of 32-bit, then call JclSysInfo.IsWindows64.

Note that JCL allso handles Editions, like Pro, Ultimate, etc. For that call GetWindowsEdition, and it returns one of these:

TWindowsEdition =
   (weUnknown, weWinXPHome, weWinXPPro, weWinXPHomeN, weWinXPProN, weWinXPHomeK,
    weWinXPProK, weWinXPHomeKN, weWinXPProKN, weWinXPStarter, weWinXPMediaCenter,
    weWinXPTablet, weWinVistaStarter, weWinVistaHomeBasic, weWinVistaHomeBasicN,
    weWinVistaHomePremium, weWinVistaBusiness, weWinVistaBusinessN,
    weWinVistaEnterprise, weWinVistaUltimate, weWin7Starter, weWin7HomeBasic,
    weWin7HomePremium, weWin7Professional, weWin7Enterprise, weWin7Ultimate);

For historical interest, you can check the NT-level edition too with the NtProductType function, it returns:

 TNtProductType =       (ptUnknown, ptWorkStation, ptServer, ptAdvancedServer,        
        ptPersonal, ptProfessional, ptDatacenterServer, 
        ptEnterprise, ptWebEdition);

Note that "N editions" are detected above. That's an EU (Europe) version of Windows, created due to EU anti-trust regulations. That's a pretty fine gradation of detection inside the JCL.

Here's a sample function that will help you detect Vista, and do something special when on Vista.

function IsSupported:Boolean;
begin
  case GetWindowsVersion of
     wvVista:  result := false; 
    else
      result := true;
  end;
end;

Note that if you want to do "greater than" checking, then you should just use other techniques. Also note that version checking can often be a source of future breakage. I have usually chosen to warn users and continue, so that my binary code doesn't become the actual source of breakage in the future.

Recently I tried to install an app, and the installer checked my drive free space, and would not install, because I had more than 2 gigabytes of free space. The 32 bit integer signed value in the installer became negative, breaking the installer. I had to install it into a VM to get it to work. Adding "smart code" often makes your app "stupider". Be wary.

Incidentally, I found that from the command line, you can run WMIC.exe, and type path Win32_OperatingSystem (The "Select * from Win32_OperatingSystem" didn't work for me). In future perhaps JCL could be extended to use the WMI information.

Answer 5

The following works for me in Windows 10 without the Windows 10 GUID listed in the application manifest:

uses
  System.SysUtils, Winapi.Windows;

type
  NET_API_STATUS = DWORD;

  _SERVER_INFO_101 = record
    sv101_platform_id: DWORD;
    sv101_name: LPWSTR;
    sv101_version_major: DWORD;
    sv101_version_minor: DWORD;
    sv101_type: DWORD;
    sv101_comment: LPWSTR;
  end;
  SERVER_INFO_101 = _SERVER_INFO_101;
  PSERVER_INFO_101 = ^SERVER_INFO_101;
  LPSERVER_INFO_101 = PSERVER_INFO_101;

const
  MAJOR_VERSION_MASK = $0F;

function NetServerGetInfo(servername: LPWSTR; level: DWORD; var bufptr): NET_API_STATUS; stdcall; external 'Netapi32.dll';
function NetApiBufferFree(Buffer: LPVOID): NET_API_STATUS; stdcall; external 'Netapi32.dll';

type
  pfnRtlGetVersion = function(var RTL_OSVERSIONINFOEXW): LONG; stdcall;
var
  Buffer: PSERVER_INFO_101;
  ver: RTL_OSVERSIONINFOEXW;
  RtlGetVersion: pfnRtlGetVersion;
begin
  Buffer := nil;

  // Win32MajorVersion and Win32MinorVersion are populated from GetVersionEx()...
  ShowMessage(Format('GetVersionEx: %d.%d', [Win32MajorVersion, Win32MinorVersion])); // shows 6.2, as expected per GetVersionEx() documentation

  @RtlGetVersion := GetProcAddress(GetModuleHandle('ntdll.dll'), 'RtlGetVersion');
  if Assigned(RtlGetVersion) then
  begin
    ZeroMemory(@ver, SizeOf(ver));
    ver.dwOSVersionInfoSize := SizeOf(ver);

    if RtlGetVersion(ver) = 0 then
      ShowMessage(Format('RtlGetVersion: %d.%d', [ver.dwMajorVersion, ver.dwMinorVersion])); // shows 10.0
  end;

  if NetServerGetInfo(nil, 101, Buffer) = NO_ERROR then
  try
    ShowMessage(Format('NetServerGetInfo: %d.%d', [Buffer.sv101_version_major and MAJOR_VERSION_MASK, Buffer.sv101_version_minor])); // shows 10.0
  finally
    NetApiBufferFree(Buffer);
  end;
end.

Update: NetWkstaGetInfo() would probably also work, similar to 'NetServerGetInfo()`, but I have not try it yet.

Answer 6

WMI QUery:

"Select * from Win32_OperatingSystem"

EDIT: Actually better would be:

"Select Version from Win32_OperatingSystem"

You could implement this in Delphi like so:

function OperatingSystemDisplayName: string;

  function GetWMIObject(const objectName: string): IDispatch;
  var
    chEaten: Integer;
    BindCtx: IBindCtx;
    Moniker: IMoniker;
  begin
    OleCheck(CreateBindCtx(0, bindCtx));
    OleCheck(MkParseDisplayName(BindCtx, PChar(objectName), chEaten, Moniker));
    OleCheck(Moniker.BindToObject(BindCtx, nil, IDispatch, Result));
  end;

  function VarToString(const Value: OleVariant): string;
  begin
    if VarIsStr(Value) then begin
      Result := Trim(Value);
    end else begin
      Result := '';
    end;
  end;

  function FullVersionString(const Item: OleVariant): string;
  var
    Caption, ServicePack, Version, Architecture: string;
  begin
    Caption := VarToString(Item.Caption);
    ServicePack := VarToString(Item.CSDVersion);
    Version := VarToString(Item.Version);
    Architecture := ArchitectureDisplayName(SystemArchitecture);
    Result := Caption;
    if ServicePack <> '' then begin
      Result := Result + ' ' + ServicePack;
    end;
    Result := Result + ', version ' + Version + ', ' + Architecture;
  end;

var
  objWMIService: OleVariant;
  colItems: OleVariant;
  Item: OleVariant;
  oEnum: IEnumvariant;
  iValue: LongWord;

begin
  Try
    objWMIService := GetWMIObject('winmgmts:\\localhost\root\cimv2');
    colItems := objWMIService.ExecQuery('SELECT Caption, CSDVersion, Version FROM Win32_OperatingSystem', 'WQL', 0);
    oEnum := IUnknown(colItems._NewEnum) as IEnumVariant;
    if oEnum.Next(1, Item, iValue)=0 then begin
      Result := FullVersionString(Item);
      exit;
    end;
  Except
    // yes, I know this is nasty, but come what may I want to use the fallback code below should the WMI code fail
  End;

  (* Fallback, relies on the deprecated function GetVersionEx, reports erroneous values
     when manifest does not contain supportedOS matching the executing system *)
  Result := TOSVersion.ToString;
end;