.net - Is this DLL managed or unmanaged?

Question

I hold before you a DLL. Using only the Win32 SDK, can you tell me if this DLL is a .NET assembly?

Why? Our application loads plugins in the form of DLLs. We are trying to extend the definition of these plugins to allow for .NET assemblies but the interface will be different and thus the loader will need to know if the DLL is managed or unmanaged before loading it.

Answer 1

To determine whether a DLL (or EXE) is managed or unmanaged, use dumpbin.exe with the /dependents switch. If you see mscoree.dll in the output, then the assembly is a managed assembly.

For example, for a managed DLL that I created in Visual Studio 2010, I get the following output:

Dump of file <MANAGED_DLL>.dll

File Type: DLL

  Image has the following dependencies:

    mscoree.dll

  Summary

        2000 .reloc
        2000 .rsrc
        2000 .sdata
       12000 .text

dumpbin.exe is delivered as part of the Visual Studio Tools. To run it, a convenient way to do so is via the Visual Studio Command Prompt. For example, from my Windows 7 machine running Visual Studio 2010, I find the Visual Studio Command Prompt in the Windows Start Menu at:

Microsoft Visual Studio 2010 => Visual Studio Tools => Visual Studio Command Prompt (2010)

Then, within the Visual Studio Command Prompt just enter:

dumpbin /dependents DLL_OF_INTEREST.DLL

or

dumpbin /dependents EXE_OF_INTEREST.EXE

---

As an alternative, you can use the corflags.exe utility that is also included with Visual Studio Tools. Running it from the Visual Studio Command Prompt on an unmanaged assembly:

corflags UNMANAGED.DLL

..you'll get:

corflags : error CF008 : The specified file does not have a valid managed header

...whereas on a managed assembly, you'll get something like:

Version   : v2.0.50727
CLR Header: 2.5
PE        : PE32
CorFlags  : 1
ILONLY    : 1
32BIT     : 0
Signed    : 0

---

Related:

• How to determine if a .NET assembly was built for x86 or x64?, and
• How can I detect the type of a dll? (COM, .NET, WIN32).