How can I determine the Windows version from a VB 6 app?

Question

I want to detect any Windows versions from 95 to Win 7.

I also would like to display if the OS is 32-bit or 64-bit.

That's it; it's that simple. :) What code could I use to do this from within a VB 6 application?

Answer 1

Update: For code that correctly detects Windows 8.1 and Windows 10, see this answer.

The code below still works fine for older versions of Windows, but it will report anything newer than Windows 8 as being Windows 8.

The "bitness" testing code shown at the bottom (to see if the OS is 32-bit or 64-bit still works, even on Windows 10.

The following code will return a string value indicating the current version of Windows. Basically, all it's doing is getting the system version numbers from Windows using the GetVersionEx API function, and then matching those up to the known versions of Windows.

(Note that some things are not detected perfectly. For example, a 64-bit version of Windows XP would likely be reported as Server 2003. Code to determine whether the user is running Windows Vista or Server 2008, for example, has also not been written. But you can take this and tweak it as desired.)

Option Explicit

Private Declare Function GetVersionEx Lib "kernel32" Alias "GetVersionExA" _
    (lpVersionInformation As OSVERSIONINFO) As Long

Private Type OSVERSIONINFO
  OSVSize         As Long
  dwVerMajor      As Long
  dwVerMinor      As Long
  dwBuildNumber   As Long
  PlatformID      As Long
  szCSDVersion    As String * 128
End Type

Private Const VER_PLATFORM_WIN32s = 0
Private Const VER_PLATFORM_WIN32_WINDOWS = 1
Private Const VER_PLATFORM_WIN32_NT = 2

' Returns the version of Windows that the user is running
Public Function GetWindowsVersion() As String
    Dim osv As OSVERSIONINFO
    osv.OSVSize = Len(osv)

    If GetVersionEx(osv) = 1 Then
        Select Case osv.PlatformID
            Case VER_PLATFORM_WIN32s
                GetWindowsVersion = "Win32s on Windows 3.1"
            Case VER_PLATFORM_WIN32_NT
                GetWindowsVersion = "Windows NT"
                
                Select Case osv.dwVerMajor
                    Case 3
                        GetWindowsVersion = "Windows NT 3.5"
                    Case 4
                        GetWindowsVersion = "Windows NT 4.0"
                    Case 5
                        Select Case osv.dwVerMinor
                            Case 0
                                GetWindowsVersion = "Windows 2000"
                            Case 1
                                GetWindowsVersion = "Windows XP"
                            Case 2
                                GetWindowsVersion = "Windows Server 2003"
                        End Select
                    Case 6
                        Select Case osv.dwVerMinor
                            Case 0
                                GetWindowsVersion = "Windows Vista/Server 2008"
                            Case 1
                                GetWindowsVersion = "Windows 7/Server 2008 R2"
                            Case 2
                                GetWindowsVersion = "Windows 8/Server 2012"
                            Case 3
                                GetWindowsVersion = "Windows 8.1/Server 2012 R2"
                        End Select
                End Select
        
            Case VER_PLATFORM_WIN32_WINDOWS:
                Select Case osv.dwVerMinor
                    Case 0
                        GetWindowsVersion = "Windows 95"
                    Case 90
                        GetWindowsVersion = "Windows Me"
                    Case Else
                        GetWindowsVersion = "Windows 98"
                End Select
        End Select
    Else
        GetWindowsVersion = "Unable to identify your version of Windows."
    End If
End Function

Additionally, if you don't need to target the earliest versions of Windows, you can get more information by passing the OSVERSIONINFOEX structure instead. I just wrote that code in C++, and the documentation is surprisingly easy to follow.

---

Determining if the host OS is 32-bit or 64-bit from a VB 6 executable is a little trickier. The reason is because VB 6 can't compile 64-bit applications. Everything you write in VB 6 will run as a 32-bit application. And 32-bit applications run on 64-bit versions of Windows in the Windows-on-Windows (WOW64) subsystem. They will always report the current version of Windows as 32-bit, because that's what they see.

We can work around this by initially assuming that the host OS is 32-bit, and attempting to prove this wrong. Here's some sample code:

Private Declare Function GetProcAddress Lib "kernel32" _
    (ByVal hModule As Long, ByVal lpProcName As String) As Long
    
Private Declare Function GetModuleHandle Lib "kernel32" _
    Alias "GetModuleHandleA" (ByVal lpModuleName As String) As Long
    
Private Declare Function GetCurrentProcess Lib "kernel32" () As Long

Private Declare Function IsWow64Process Lib "kernel32" _
    (ByVal hProc As Long, ByRef bWow64Process As Boolean) As Long

Public Function IsHost64Bit() As Boolean
    Dim handle As Long
    Dim is64Bit As Boolean

    ' Assume initially that this is not a WOW64 process
    is64Bit = False

    ' Then try to prove that wrong by attempting to load the
    ' IsWow64Process function dynamically
    handle = GetProcAddress(GetModuleHandle("kernel32"), "IsWow64Process")

    ' The function exists, so call it
    If handle <> 0 Then
        IsWow64Process GetCurrentProcess(), is64Bit
    End If

    ' Return the value
    IsHost64Bit = is64Bit
End Function