Question

I have a C++/CLI DLL that uses some managed code (written in C#). I want to export a pure C function from the DLL – it will be called from unmanaged code using LoadLibrary and GetProcAddress.

In the exported function I just need to create an instance and call one method of a C# class. So I tried this:

extern "C" __declspec( dllexport ) int __stdcall DoWork(
       const wchar_t* Param1,
       int Param2,
       void* Param3)
{
    WorkerNamespace::ManagedClass1 worker;
    return worker.DoWork( gcnew String(Param1), Param2, IntPtr( Param3 ) );
}

It compiles fine but when I do a dumpbin CompiledDll.dll /exports there are no exported functions.

I tried adding #pragma unmanaged before the function declaration but then I get errors for using managed types inside the body.

If I replace the body of the function with an empty stub (just return 1;) and with #pragma unmanaged, the function still doesn’t show up in dumpbin. So what am I doing wrong? How do I export a C function from a C++/CLI Class Library project?

Answer 1

Must have been a configuration issue. I created a new project using the Empty project template, changed

Configuration Type to Dynamic Library (.dll)

Common Language Runtime Support to Common Language Runtime Support (/clr)

in General Configuration and added a reference to System.Core and my C# assembly in Common Properties and it works now.

I also added a .DEF file to handle name mangling (the def file’s name should, of course, be set in Linker -> Input -> Module Definition file).

LIBRARY
EXPORTS
DoWork

Hope that helps someone else.