C++/CLI lib with 1 function to be statically linked with native C++

Question

I would like to accomplish a simple task: I want to produce a C++/CLI lib that calls some .NET routines, and exposes 1 static method that I can call from purely native C++ app. I want to statically link to that lib from my native app. The signature of the method that the native C++ app would call should be

void (unsigned char* data, int length, _TCHAR* args[])

I am pretty new to C++/CLI and C++ in general. So, can you please help me and answer these questions:

1. For my tiny C++/CLI project, I assume the type needs to be class library with lib as output, targeting vc9 runtime (so that I can be sure it is available on end users PCs). Am I correct in this assumption?

2. Can you provide an example of the outline of the method with that signature I will need to write in my C++/CLI project. In particular how should I do conversion to CLR types properly (ie byte[], int32, and string)? And how do I decorate that method with something like "extern "C" __declspec(dllexport)" to make this method callable from my native C++ app?

3. How would I separate the code between cpp and h files in C++/CLI properly?

4. Finally how would I actually call it from my native app once I add lib reference?

Thank you.

Answer 1

1. Class library: correct, but you'll also need to change your project's configuration type from Dynamic Library to Static Library. I'm not sure what you mean by 'targeting vc9 runtime' – you need to target the same runtime as the native code that will be using your static library.

2. Since this is a static library, no __declspec(dllexport) is needed. If you want to know how to do conversion to .NET types, you'll need to post what your code is actually doing. In general, you'll want Marshal::Copy to copy a C-array into a .NET array, and marshal_as<> to copy C-strings into .NET strings, but there's still the question as to whether that data is intended to be mutable and needs to be marshaled back to native types before returning...

3. The exact same as in C++ – declaration in a header, definition in a source file.

4. The exact same as any other function – #include the header containing the declaration and call the function.