There's always been a fight over an optimal way to detect bitness of an OS. Most of the time, getting system information is considered to be solved using interop services or P/Invoke. For this, the methodology followed is as shown below:
public enum Platform
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;
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;
internal static extern void GetNativeSystemInfo(ref SYSTEM_INFO lpSystemInfo);
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))
Actually there's a simple way to do that in C#. C# provides a very useful struct
64-Bit Vs 32-Bit w.r.t Pointer
We all know that the size of an Pointer
on a 32-bit
compiled program is 4-Bytes. The size changes on a 64-Bit compiled program and becomes 8-bytes.
Then why not compare the size of Integer. Pointer is nothing but an Integer and
IntPtr serves the same for us in C#.
The following example shows the simple usage of
(UPDATE: As Win64 follows LLP64 Model (For more informarion on LLP64 model please follow Technet Article
]) as corrected by codeproject member Ajay Vijayvargiya
if(IntPtr.size == 4)
Previous code checks whether the program is running in 32-bit or 64-bit mode. This doesn't inform OS bitness.
If using C++/Win32:
IntPtr is not available in C++. Rather
sizeof(int) does the same.
BOOL bIs64Bit = FALSE;
bIs64Bit = TRUE;
typedef BOOL (WINAPI *LPFNISWOW64PROCESS) (HANDLE, PBOOL);
LPFNISWOW64PROCESS pfnIsWow64Process = (LPFNISWOW64PROCESS)GetProcAddress(GetModuleHandle(_T("kernel32")), "IsWow64Process");
There's one more distinctive feature a 64-Bit OS supports: "Virtualization".
Virtualization (Windows Vista and 7 x64 Platform only)
Virtualization technologies are used by Windows Vista and 7 x64 platform only. These act like virtual machines just like VMWare or similar apps. The advantage here is to run legacy apps such s 32-bit apps. Running 32-Bit apps on 64-Bit OS becomes difficult without virtualization as such applications are usually not written to co-exist within a single execution environment.
64-Bit applications are never run virtualized, nor do 32 or 64-Bit services and drivers. Virtualization becomes active when running legacy 32-bit interactive apps under WOW64.
So if the OS supports virtualization, then it got to be 64-Bit.
You can use the following code to check whether the app is running as virtualized:
[DllImport("advapi32.dll", EntryPoint = "GetTokenInformation",
SetLastError = true)]
static extern bool GetTokenInformationNative(
ref int TokenInformation,
out int ReturnLength);
public bool IsVirtualized(IntPtr token)
bool virtualized = false;
int len = 4;
int info = 0;
if (!GetTokenInformationNative(token, 24, ref info, len, out
string s = "Win32 error " +
throw new Exception(s);
if(info != 0)
virtualized = true;
Thanks to Luc Pattyn
] and Ajay Vijayvargiya
] to point out the errors.