Just as a follow-up, I determined there are more issues regarding compatibility with C++, which is why I could not get a pointer returned on gretl_model_get_matrix. It's not as simple as just using extern "C" {} when compiling the headers as I first thought. It's only regarding specific gretl features, though.

I'll experiment with some compilers when I have more time. Obviously, anyone attempting to use gretl libraries directly from a c++ program should be parallel testing against the app to ensure you are getting the expected results on a case-by-case basis. Overall though I have had decent success adapting it, thanks again.

Joel