All the global symbols of the Freecell Solver modules are prefixed with fc_solve_ prefix. (See this post to the fc-solve-discuss mailing list about why we converted away from freecell_solver_. Some macros supplied to the user are prefixed with the fcs_ prefix for convenience. The API functions in turn are prefixed with freecell_solver_user_, in order to not break compatibility with older versions of the library.