Error when compiling shared object: C++ class definition not being detected

I'm trying to compile a shared library that will be used as a plugin to some testing software I am writing that will check the viability of navigational algorithms for a robot. The testing software loads a shared object containing the definition of an object representing an implementation of a navigation algorithm, as well as a factory method to generate said object. The software then uses this object to test the algorithm's viability under known conditions. In a nutshell, the software is going to give the algorithm a starting point and a reference to a representation of the course before handing over the reigns. But all this is beside the point.I'm trying to compile a shared library that wil