C# Signature:

[DllImport("kernel32.dll")]
internal static extern void GetNativeSystemInfo(ref SYSTEM_INFO lpSystemInfo);

VB Signature:

Private Declare Sub GetNativeSystemInfo Lib "kernel32" (<MarshalAs(UnmanagedType.Struct)> ByRef lpSystemInfo As SYSTEM_INFO)

User-Defined Types:

SYSTEM_INFO

Alternative Unmanaged API:

GetSystemInfo

Notes:

This sample will determine is the os supports 64bit.

Tips & Tricks:

Please add some!

Sample Code:

    public enum Platform
    {
      X86,
      X64,
      IA64,
      Unknown
    }

    internal const ushort PROCESSOR_ARCHITECTURE_INTEL = 0;
    internal const ushort PROCESSOR_ARCHITECTURE_IA64 = 6;
    internal const ushort PROCESSOR_ARCHITECTURE_AMD64 = 9;
    internal const ushort PROCESSOR_ARCHITECTURE_UNKNOWN = 0xFFFF;

    [StructLayout(LayoutKind.Sequential)]
    internal struct SYSTEM_INFO
    {
      public ushort wProcessorArchitecture;
      public ushort wReserved;
      public uint dwPageSize;
      public IntPtr lpMinimumApplicationAddress;
      public IntPtr lpMaximumApplicationAddress;
      public UIntPtr dwActiveProcessorMask;
      public uint dwNumberOfProcessors;
      public uint dwProcessorType;
      public uint dwAllocationGranularity;
      public ushort wProcessorLevel;
      public ushort wProcessorRevision;
    };

    [DllImport("kernel32.dll")]
    internal static extern void GetNativeSystemInfo(ref SYSTEM_INFO lpSystemInfo);

    [DllImport("kernel32.dll")]
    internal static extern void GetSystemInfo(ref SYSTEM_INFO lpSystemInfo);

    public static Platform GetPlatform()
    {
      SYSTEM_INFO sysInfo = new SYSTEM_INFO();

      if(System.Environment.OSVersion.Version.Major > 5 ||
    (System.Environment.OSVersion.Version.Major == 5 && System.Environment.OSVersion.Version.Minor >= 1))
      {
    GetNativeSystemInfo(ref sysInfo);
      }
      else
      {
    GetSystemInfo(ref sysInfo);
      }

      switch(sysInfo.wProcessorArchitecture)
      {
    case PROCESSOR_ARCHITECTURE_IA64:
      return Platform.IA64;

    case PROCESSOR_ARCHITECTURE_AMD64:
      return Platform.X64;

    case PROCESSOR_ARCHITECTURE_INTEL:
      return Platform.X86;

    default:
      return Platform.Unknown;
      }
    }