C++ module build: undefined symbol

I'm writing a Python C++ module to run C++ code from within my Python code.

In my module C++ file, I #include<myClass.h> and use the functions defined in myClass. When I build the module I get the following error:



Is it not enough to include the header file of the type I'm going to be using in my C++ module file. I'm not going to be calling any of these functions from my Python code so I don't see the need to add these functions to the methods table.

How can I include C++ GSL (Gnu Scientific Library) in this file also?