I have a bunch or C wrappers for C++ OpenCV code I'm writing and I was hoping someone could show me how the best way would be in CFFI to write theses functions.  They're from a C++ class the OpenCV Point_ class defined here http://docs.opencv.org/modules/core/doc/basic_structures.html?highlight=assi... Here are the functions below. So far I'm making the top 2 functions point0 and point2 use the same name "point" with this function: (defun point (&optional (x nil) (y nil))        (cond ((eq (or x y) nil)           (point0))          ((and x y)           (point2 x y))          (t nil)))   but I also have functions  to retrieve the x and y coordinates of a point that belong to the same class. I call those point-x and point-y..I was hoping someone could write me up the best way on how to use these Point_ class wrappers . Is it with defclass or define-foreign-type or am I already doing a good job? I could use this info in making all my other class wrappers correctly. ;; Point* cv_create_Point(int x, int y)  (defcfun ("cv_create_Point" point0) (:pointer point)   "Point constructor")     ;; Point* cv_create_Point(int x, int y)  (defcfun ("cv_create_Point2" point2) (:pointer point)   "Point constructor"   (x :int)   (y :int))   ;; _Tp x, y ;; int cv_Point_getX(Point* self)  (defcfun ("cv_Point_getX" point-x) :int    "Retrieves X coordinate of a point"   (self (:pointer point)))     ;; _Tp x, y ;; int cv_Point_getY(Point* self) (defcfun ("cv_Point_getY" point-y) :int    "Retrieves y coordinate of a point"   (self (:pointer point)))