How do I expose erl_interface (Erlang's C library) through a DLL?

Question

I've been working non-stop for the last three days on a completely managed interface to Erlang. At this point, I've decided that there simply must be an easier way. I've got a little over 3000 lines and it's not even in a compilable state yet. To be honest, I'm getting lost in my own code.

So, I then remembered that Erlang has a C library called erl_interface. Unfortunately, it only comes as a .LIB file, which isn't usable via P/Invoke. I'm now investigating ways to expose the static library through a DLL.

I'd like to stay away from Visual C++, mostly because I'm not a C/C++ programmer by nature and I find it really difficult to configure. TinyC is my compiler of choice when working with anything in C.

How can I go about this?

I know I can link erl_interface to a DLL, but how can I expose the functions? Do I have to essentially wrap each and every one of them in my own exports? That probably won't be a problem, since I could write a script to generate the code from the header file. But is there an easier way that I just don't know about?

Also, please don't recommend OTP.NET. It's a nice library, but I'm looking to use this is a large project, so I'd like to keep it in-house.

Answer 1

So, your problem is one of turning a static lib into a dynamic one.

The least-effort solution would be to write a thin shim file in 'C', that just delegates to the files in the .lib e.g.

ReturnType my_method1(args...) {
  return real_method1(args...);
}
...

and build a DLL from that and the static lib.

Afterthought -- There is another approach you could take -- which is build the .lib into a C++/CLI assembly and do the transition/wrapping in that. It's what C++/CLi is there for, after all.

Answer 2

If you want some help with interfacing to Erlang with C, have a look at "EPAPI" (Erlang Port API) link text. You can of course browse the source code since it is hosted on Google Code. A DEBIAN repository is also available.