How do I test an existing managed .NET .dll to see if its 32-bit or 64-bit?

Question

Known dead ends:

"dumpbin /header" doesn't work, it returns 32-bit for everything (its only looking at the native win32 headers).
Dependency Walker doesn't work, as its for native win32 .dll's.

score 10 · Accepted Answer · answered Mar 02 '11 at 12:29

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Start up Visual Studio 2008 Command Prompt, go to the folder your assembly is in type "corflags.exe assemblyName.dll" and you should get the following info back

Version   : v4.0.30319
CLR Header: 2.5
PE        : PE32
CorFlags  : 1
ILONLY    : 1
32BIT     : 0
Signed    : 0

answered Mar 02 '11 at 12:29

Iain

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For VS 2012, CorFlags shows 32BITREQ(UIRED) and 32BITPREF(ERRED). See http://blogs.microsoft.co.il/blogs/sasha/archive/2012/04/04/what-anycpu-really-means-as-of-net-4-5-and-visual-studio-11.aspx and http://msdn.microsoft.com/en-us/library/ms164699%28v=vs.110%29.aspx . – TrueWill May 22 '13 at 14:27

score 1 · Answer 2 · edited May 23 '17 at 11:51

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See How to determine if a .NET assembly was built for x86 or x64?

edited May 23 '17 at 11:51

Community

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answered Mar 02 '11 at 12:31

Contango

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This question also gives the answer, but it doesn't include the keywords "managed", "32-bit" or "64-bit", so its a bit difficult to quickly navigate to it. – Contango Mar 02 '11 at 12:41

How do I test an existing managed .NET .dll to see if its 32-bit or 64-bit?

2 Answers2