How to Detect Windows 64-Bit Platform With .Net

How to detect Windows 64-bit platform with .NET?

UPDATE: As Joel Coehoorn and others suggest, starting at .NET Framework 4.0, you can just check Environment.Is64BitOperatingSystem.

IntPtr.Size won't return the correct value if running in 32-bit .NET Framework 2.0 on 64-bit Windows (it would return 32-bit).

As Microsoft's Raymond Chen describes, you have to first check if running in a 64-bit process (I think in .NET you can do so by checking IntPtr.Size), and if you are running in a 32-bit process, you still have to call the Win API function IsWow64Process. If this returns true, you are running in a 32-bit process on 64-bit Windows.

Microsoft's Raymond Chen:
How to detect programmatically whether you are running on 64-bit Windows

My solution:

static bool is64BitProcess = (IntPtr.Size == 8);
static bool is64BitOperatingSystem = is64BitProcess || InternalCheckIsWow64();

[DllImport("kernel32.dll", SetLastError = true, CallingConvention = CallingConvention.Winapi)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool IsWow64Process(
    [In] IntPtr hProcess,
    [Out] out bool wow64Process
);

public static bool InternalCheckIsWow64()
{
    if ((Environment.OSVersion.Version.Major == 5 && Environment.OSVersion.Version.Minor >= 1) ||
        Environment.OSVersion.Version.Major >= 6)
    {
        using (Process p = Process.GetCurrentProcess())
        {
            bool retVal;
            if (!IsWow64Process(p.Handle, out retVal))
            {
                return false;
            }
            return retVal;
        }
    }
    else
    {
        return false;
    }
}

How to determine if OS is 32 or 64 bit cross-platform on .NET Standard 1.5?

You can use System.Runtime.InteropServices.RuntimeInformation.OSArchitecture

How to check if OS is 32 Bit OS or 64 Bit

Environment.Is64BitOperatingSystem should do nicely.

Determines whether the current operating system is a 64-bit operating system.

The assumption being that a false signifies a 32bit environment.

If you want to find out if the process is 64bit (as you can run a 32bit process on a 64bit OS), use Environment.Is64BitProcess:

Determines whether the current process is a 64-bit process.

Both of these have been introduced in .NET 4.0.

How can my program determine if it is running on 32-bit or 64-bit Windows?

How to detect Windows 64 bit platform with .net? might be helpful.

How do I determine if a .NET application is 32 or 64 bit?

If you're trying to check whether or not a running application is running in 32-bit or 64-bit mode, open task manager and check whether or not it has an asterisk (*32) next to the name of the process.

EDIT (imported from answer by manna): As of Win8.1, the "bittyness" of a process is listed in a separate detail column labelled Platform. (Right click on any column header to expose the select columns menu.)

If you have a compiled dll and you want to check if it's compiled for 32-bit or 64-bit mode, do the following (from a related question). I would think that you want you dll to be compiled for AnyCPU.

Open Visual Studio Command Prompt and type "corflags [your assembly]". You'll get something like this:


c:\Program Files (x86)\Microsoft Visual Studio 9.0\VC>corflags "C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Data.dll"
    
Microsoft (R) .NET Framework CorFlags Conversion Tool. Version 3.5.21022.8 Copyright (c) Microsoft Corporation. All rights reserved.
    
Version : v2.0.50727
CLR Header: 2.5
PE : PE32
CorFlags : 24
ILONLY : 0
32BIT : 0
Signed : 1

You're looking at PE and 32BIT specifically.

AnyCpu:

PE: PE32
32BIT: 0

x86:

PE: PE32
32BIT: 1

x64:

PE: PE32+
32BIT: 0

.NET 2.0 Framework in C# check if 64bit os if so do this? if not do this? better answer?

You can use Reflector to look how it is implemented in FW 4.0:

[DllImport("kernel32.dll", CharSet=CharSet.Ansi, SetLastError=true, ExactSpelling=true)]
private static extern IntPtr GetProcAddress(IntPtr hModule, string methodName);

[ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail), DllImport("kernel32.dll", CharSet=CharSet.Auto, SetLastError=true)]
private static extern IntPtr GetModuleHandle(string moduleName);

[DllImport("kernel32.dll", CharSet=CharSet.Auto, SetLastError=true)]
internal static extern IntPtr GetCurrentProcess();

[SecurityCritical]
internal static bool DoesWin32MethodExist(string moduleName, string methodName)
{
   IntPtr moduleHandle = GetModuleHandle(moduleName);
   if (moduleHandle == IntPtr.Zero)
   {
       return false;
   }
   return (GetProcAddress(moduleHandle, methodName) != IntPtr.Zero);
}

[return: MarshalAs(UnmanagedType.Bool)]
[DllImport("kernel32.dll", SetLastError=true)]
internal static extern bool IsWow64Process([In] IntPtr hSourceProcessHandle, [MarshalAs(UnmanagedType.Bool)] out bool isWow64);

[SecuritySafeCritical]
public static bool get_Is64BitOperatingSystem()
{
    bool flag;
    return (IntPtr.Size == 8) ||
        ((DoesWin32MethodExist("kernel32.dll", "IsWow64Process") &&
        IsWow64Process(GetCurrentProcess(), out flag)) && flag);
}

It checks if IsWow64Process() function exists, and calls it.

Update: added all functions used by get_Is64BitOperatingSystem()

Update2: fixed for 64-bit process

How can I determine if a .NET assembly was built for x86 or x64?

Look at System.Reflection.AssemblyName.GetAssemblyName(string assemblyFile).

You can examine assembly metadata from the returned AssemblyName instance:

Using PowerShell:


[36] C:\> [reflection.assemblyname]::GetAssemblyName("${pwd}\Microsoft.GLEE.dll") | fl

Name                  : Microsoft.GLEE
Version               : 1.0.0.0
CultureInfo           :
CodeBase              : file:///C:/projects/powershell/BuildAnalyzer/...
EscapedCodeBase       : file:///C:/projects/powershell/BuildAnalyzer/...
ProcessorArchitecture : MSIL
Flags                 : PublicKey
HashAlgorithm         : SHA1
VersionCompatibility  : SameMachine
KeyPair               :
FullName              : Microsoft.GLEE, Version=1.0.0.0, Culture=neut...

Here, ProcessorArchitecture identifies the target platform.

Amd64: A 64-bit processor based on the x64 architecture.
Arm: An ARM processor.
IA64: A 64-bit Intel Itanium processor only.
MSIL: Neutral with respect to processor and bits-per-word.
X86: A 32-bit Intel processor, either native or in the Windows on Windows environment on a 64-bit platform (WoW64).
None: An unknown or unspecified combination of processor and bits-per-word.

I'm using PowerShell in this example to call the method.

How can I detect in code if my solution is x86 or x64?

You can use Environment.Is64BitProcess to determine if the current process is a 64 or 32 bit process.

How to determine programmatically whether a particular process is 32-bit or 64-bit

One of the more interesting ways I've seen is this:

if (IntPtr.Size == 4)
{
    // 32-bit
}
else if (IntPtr.Size == 8)
{
    // 64-bit
}
else
{
    // The future is now!
}

To find out if OTHER processes are running in the 64-bit emulator (WOW64), use this code:

namespace Is64Bit
{
    using System;
    using System.ComponentModel;
    using System.Diagnostics;
    using System.Runtime.InteropServices;

    internal static class Program
    {
        private static void Main()
        {
            foreach (var p in Process.GetProcesses())
            {
                try
                {
                    Console.WriteLine(p.ProcessName + " is " + (p.IsWin64Emulator() ? string.Empty : "not ") + "32-bit");
                }
                catch (Win32Exception ex)
                {
                    if (ex.NativeErrorCode != 0x00000005)
                    {
                        throw;
                    }
                }
            }

            Console.ReadLine();
        }

        private static bool IsWin64Emulator(this Process process)
        {
            if ((Environment.OSVersion.Version.Major > 5)
                || ((Environment.OSVersion.Version.Major == 5) && (Environment.OSVersion.Version.Minor >= 1)))
            {
                bool retVal;

                return NativeMethods.IsWow64Process(process.Handle, out retVal) && retVal;
            }

            return false; // not on 64-bit Windows Emulator
        }
    }

    internal static class NativeMethods
    {
        [DllImport("kernel32.dll", SetLastError = true, CallingConvention = CallingConvention.Winapi)]
        [return: MarshalAs(UnmanagedType.Bool)]
        internal static extern bool IsWow64Process([In] IntPtr process, [Out] out bool wow64Process);
    }
}

How to Detect Windows 64-Bit Platform With .Net