Visual Studio 2010 C++/CLI in Static Library Mode: could not find assembly 'mscorlib.dll'

Question

I am working on a C++/CLI project with VS 2012 in Dynamic Library (.dll) and x64 mode.

If I switch the mode to Static Library, I get the error below.

Er

Answer 1

If I switch the mode to Static Library

This is not the typical error you get when you try to build a static library with /clr in effect. I'd have to assume you've been tinkering with project settings to get rid of the inscrutable linker errors you get when you try to do this.

Core issue is that the C++/CLI build system doesn't support static libraries that contain MSIL. Managed code doesn't use a linker, binding happens at runtime. Which makes the essential difference between static libraries and DLLs disappear. So Microsoft decided to not support it because it didn't make much sense to implement it. Unfortunately they don't yell loud enough when you try to do it anyway, the linker errors you get don't give enough of a hint what you did wrong. Workarounds, like merging with ILMerge don't work either, it cannot deal with mixed-mode assemblies. Merging the native code sections and their associated relocation table entries is very untrivial.

Keep in mind that it is fine to link native static libraries. A typical C++/CLI project has only the ref class wrappers that need to be built with /clr in effect. You can glue any amount of native code from libraries into the final assembly.

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I'm forced to theorize about the actual compile error, too many programmers get this error for another reason that doesn't have anything to do with building static libraries and they are harassing me in the comments.

Do beware that targeting a different version of .NET than the one you have installed on your machine is quite a hazardous affair, particularly so if you want to target 4.0 and you have 4.5.x installed. The key element in your .vcxproj file is the . This will be missing if you started the project targeting an old .NET version, you have to insert it yourself. The IDE also doesn't support changing it if it is present, again edit by hand.

Which is enough to coax MSBuild into generating the proper compile command. You can verify if that panned-out well, look in the *.tlog subdirectory of the Debug build directory for your project. The cl.command.1.tlog file shows the options that were passed to the compiler. It should contain:

/AI"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.0"
/FU"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.0\mscorlib.dll"

Note the subdirectory, very important that it matches your intended .NET target. v4.0 in this example. And very, very important that it does not point to c:\windows\microsoft.net, the legacy location for reference assemblies.