Getting Windows OS version programmatically

Question

I am trying to fetch Windows version with C# on my Windows 10 machine.

I always get those values (with C#\C++):

Major: 6

Minor: 2

Which is Windows 8 OS, accordingly to MSDN

C# code:

var major = OperatingSystem.Version.Major
var minor  = OperatingSystem.Version.Minor

C++ code

void print_os_info()
{
    //http://stackoverflow.com/questions/1963992/check-windows-version
    OSVERSIONINFOW info;
    ZeroMemory(&info, sizeof(OSVERSIONINFOW));
    info.dwOSVersionInfoSize = sizeof(OSVERSIONINFOW);

    LPOSVERSIONINFOW lp_info = &info;
    GetVersionEx(lp_info);

    printf("Windows version: %u.%u\n", info.dwMajorVersion, info.dwMinorVersion);
}

Windows 10 suppose to be with those:

Major: 10

Minor: 0*

• (When I am taking a dump file from running process I can see that the OS version of that file is set to 10.0)

built by: 10.0.10586.0 (th2_release.151029-1700)

What am I missing here?

Answer 1

As the accepted answer is only for C#, here is a solution for C++.

It uses the RtlGetVersion in the ntdll.dll that uses the same structure as GetVersionEx (name is different, but the elements are the same) and gives you the correct version. As this function is normally used for driver development, the function is declared in the DDK and not in the SDK. So I used a dynamic solution to call the function. Please be aware that the ntdll.dll is loaded and released in every call. So if you need the function more often, keep the library loaded.

The structure pOSversion is pointing to must be initialized like for GetVersionEx.

BOOL GetTrueWindowsVersion(OSVERSIONINFOEX* pOSversion)
{
   // Function pointer to driver function
   NTSTATUS (WINAPI *pRtlGetVersion)(
      PRTL_OSVERSIONINFOW lpVersionInformation) = NULL;

   // load the System-DLL
   HINSTANCE hNTdllDll = LoadLibrary("ntdll.dll");

   // successfully loaded?
   if (hNTdllDll != NULL)
   {
      // get the function pointer to RtlGetVersion
      pRtlGetVersion = (NTSTATUS (WINAPI *)(PRTL_OSVERSIONINFOW))
            GetProcAddress (hNTdllDll, "RtlGetVersion");

      // if successfull then read the function
      if (pRtlGetVersion != NULL)
         pRtlGetVersion((PRTL_OSVERSIONINFOW)pOSversion);

      // free the library
      FreeLibrary(hNTdllDll);
   } // if (hNTdllDll != NULL)

   // if function failed, use fallback to old version
   if (pRtlGetVersion == NULL)
      GetVersionEx((OSVERSIONINFO*)pOSversion);

   // always true ...
   return (TRUE);
} // GetTrueWindowsVersion