Private Structure OSVERSIONINFO

    Dim dwOSVersionInfoSize As Integer

    Private Declare Function GetVersionEx Lib "kernel32" Alias "GetVersionExA" (ByRef lpVersionInformation As OSVERSIONINFO) As Integer

    Dim o As OSVERSIONINFO

    o.dwOSVersionInfoSize = Len(o)

    Dim o As OSVERSIONINFO

    o.dwOSVersionInfoSize = Len(o)

public static extern int CeGetVersionEx(ref CEOSVERSIONINFO ceosver);

CEOSVERSIONINFO

public struct CEOSVERSIONINFO

    public UInt32 dwOSVersionInfoSize;

Public Structure CEOSVERSIONINFO

    Public dwOSVersionInfoSize As UInt32

struct OSVERSIONINFOEX {

   public int dwOSVersionInfoSize;  

  struct OSVERSIONINFOEX

    public uint dwOSVersionInfoSize;

Structure OSVERSIONINFOEX

   Public dwOSVersionInfoSize As Integer

End Structure 'OSVERSIONINFOEX

struct OSVERSIONINFOEX {

   public int dwOSVersionInfoSize;  

Structure OSVERSIONINFOEX

   Public dwOSVersionInfoSize As Integer

End Structure 'OSVERSIONINFOEX

private static extern bool GetVersionEx(ref OSVERSIONINFOEX osvi);

private struct OSVERSIONINFOEX

    public uint dwOSVersionInfoSize;

    (ByRef lpVersionInformation As OSVERSIONINFOEX) As Boolean

    Structure OSVERSIONINFOEX

    Public dwOSVersionInfoSize As Integer

    End Structure 'OSVERSIONINFOEX

    Dim osv As New OSVERSIONINFOEX

    osv.dwOSVersionInfoSize = Marshal.SizeOf(osv)

    Dim osv As New OSVERSIONINFOEX

    osv.dwOSVersionInfoSize = Marshal.SizeOf(osv)

don't forget to set the dwOSVersionInfoSize  

OSVERSIONINFOEX osVersionInfo = new OSVERSIONINFOEX();

osVersionInfo.dwOSVersionInfoSize = Marshal.SizeOf(osVersionInfo); // don't forget this line, please!

GetVersionEx(ref osVersionInfo);

   Private Declare Ansi Function GetVersionEx Lib "kernel32" Alias "GetVersionExA" (ByRef i As OSVERSIONINFO) As Boolean

   Public Structure OSVERSIONINFO

       Public dwOSVersionInfoSize As Integer

// This must be used if OSVERSIONINFO is defined as a struct or Class - The previous [In,Out] parameter defined for

static extern bool GetVersionEx( ref OSVERSIONINFO osvi );  

' This must be used if OSVERSIONINFO is defined as a struct

Private Shared Function GetVersionEx(ByRef osvi As OSVERSIONINFO) As Boolean

' This must be used if OSVERSIONINFO is defined as a class

Private Shared Function GetVersionEx(<[In](), Out()> ByVal osvi As OSVERSIONINFO) As Boolean

OSVERSIONINFO

If you forget to set the OSVersionInfoSize field of the OSVERSIONINFO struct, the function will return false. GetLastError() will return:

Using the OSVERSIONINFO class and corresponding signature:

Console.WriteLine( "\nPassing OSVERSIONINFO as class" );

OSVERSIONINFO osvi = new OSVERSIONINFO();

osvi.OSVersionInfoSize = Marshal.SizeOf( osvi );

Console.WriteLine( "Class size:    {0}", osvi.OSVersionInfoSize );

Using the OSVERSIONINFO struct and corresponding signature:

Console.WriteLine( "\nPassing OSVERSIONINFO as struct" );

OSVERSIONINFO osvi2 = new OSVERSIONINFO();

osvi2.OSVersionInfoSize = Marshal.SizeOf(ref typeof(OSVERSIONINFO) );

Console.WriteLine( "Struct size:   {0}", osvi2.OSVersionInfoSize );

// This must be used if OSVERSIONINFO is defined as a struct or Class - The previous [In,Out] parameter defined for

static extern bool GetVersionEx( ref OSVERSIONINFO osvi );  

' This must be used if OSVERSIONINFO is defined as a struct

Private Shared Function GetVersionEx(ByRef osvi As OSVERSIONINFO) As Boolean

' This must be used if OSVERSIONINFO is defined as a class

Private Shared Function GetVersionEx(<[In](), Out()> ByVal osvi As OSVERSIONINFO) As Boolean

OSVERSIONINFO

If you forget to set the OSVersionInfoSize field of the OSVERSIONINFO struct, the function will return false. GetLastError() will return:

Using the OSVERSIONINFO class and corresponding signature:

Console.WriteLine( "\nPassing OSVERSIONINFO as class" );

OSVERSIONINFO osvi = new OSVERSIONINFO();

osvi.OSVersionInfoSize = Marshal.SizeOf( osvi );

Console.WriteLine( "Class size:    {0}", osvi.OSVersionInfoSize );

Using the OSVERSIONINFO struct and corresponding signature:

Console.WriteLine( "\nPassing OSVERSIONINFO as struct" );

OSVERSIONINFO osvi2 = new OSVERSIONINFO();

osvi2.OSVersionInfoSize = Marshal.SizeOf(ref typeof(OSVERSIONINFO) );

Console.WriteLine( "Struct size:   {0}", osvi2.OSVersionInfoSize );

    Dim osv As New OSVERSIONINFOEX

    osv.dwOSVersionInfoSize = Marshal.SizeOf(osv)

    Dim osv As New OSVERSIONINFOEX

    osv.dwOSVersionInfoSize = Marshal.SizeOf(osv)

static extern bool VerifyVersionInfo([In] ref OSVERSIONINFOEX lpVersionInfo,

private struct OSVERSIONINFOEX

   public uint dwOSVersionInfoSize;