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