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

Question

Here's my question. What is the best way to determine what bit architecture your app is running on?

What I am looking to do: On a 64 bit server I want my app to read 64 bit datasources (stored in reg key Software\Wow6432Node\ODBC\ODBC.INI\ODBC Data Sources) and if its 32 bit I want to read 32 bit datasources, (i.e. Read from Software\ODBC\ODBC.INI\ODBC Data Sources).

I might be missing the point, but I don't want to care what mode my app is running in. I simply want to know if the OS is 32 or 64 bit.

[System.Environment.OSVersion.Platform doesn't seem to be cutting it for me. Its returning Win32NT on my local xp machine and on a win2k8 64 bit server (even when all my projects are set to target 'any cpu')]

Duplicate of http://stackoverflow.com/questions/266082/how-do-i-tell-if-my-application-is-running-as-a-32-or-64-bit-application — Redwood, May 19 '10 at 16:28

score 4 · Answer 1 · answered May 19 '10 at 15:20

4

You shouldn't even worry about this, normally. The system automatically redirects registry queries to Software\Wow6432Node when running a 32-bit app on a 64-bit platform.

answered May 19 '10 at 15:20

JSBձոգչ

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To make your app run as 32-bit regardless of the platform, change the exe platform to "x86 only". It will still run on x64 platforms and be automatically redirected to the Wow6432Node keys. – Stephen Cleary May 19 '10 at 15:22

score 4 · Answer 2 · answered May 19 '10 at 15:20

4

Try the property Environment.Is64BitOperatingSystem. This is a new one added in .Net 4.0 specifically for the purpose of checking the type of the operating system.

answered May 19 '10 at 15:20

JaredPar

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Thanks but I should have mentioned I'm restricted to .net 2.0 – user48408 May 19 '10 at 15:39

score 4 · Answer 3 · answered May 19 '10 at 15:47

4

Simple, safe, framework version agnostic solution without going to the registry:

Console.WriteLine(
    "Is 64-bit? {0}",
    (
        System.Runtime.InteropServices.Marshal.SizeOf(typeof(IntPtr)) == sizeof(Int64)
            ? "Yes" 
            : "No"
    )
);

answered May 19 '10 at 15:47

Nathan Ernst

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Yes but if its running in 32 bit mode on a 64 bit machine the above would return false no? – user48408 May 20 '10 at 14:19

score 2 · Answer 4 · answered May 19 '10 at 15:20

2

You should not read Wow6432Node directly. Use RegistryView to specify a 32-bit view when running as a 64-bit app.

answered May 19 '10 at 15:20

Stephen Cleary

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Unfortunately `RegistryView` available only from .NET 4.0. – Regent May 19 '10 at 15:33

score 1 · Accepted Answer · edited May 23 '17 at 12:26

1

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

edited May 23 '17 at 12:26

Community

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1

answered May 19 '10 at 15:32

Regent

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I used this thanks. Thanks everyone else for their help also. – user48408 May 20 '10 at 15:18

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

5 Answers5