[Cffi-devel] What is the proper way to do GC in CFFI

I have Lisp functions that wrap C wrappers for C++ functions that contain a new operator. The C wrappers have to stay the same I can't change those but I was advised to update my method of GC.

Here are the C wrappers:

Mat* cv_create_Mat() {     return new Mat(); }

void cv_delete_Mat(void* ptr) {     delete (~Mat*)ptr; }

Here are the Lisp wrappers for them:

(defcfun ("cv_create_Mat" mat) (:pointer mat)   "MAT constructor")

(defcfun ("cv_delete_Mat" del-mat) :void   (ptr :pointer))

In a loop, as below, I would normally after calling a MAT function, delete it when I'm done with it manually with DEL-MAT, but I heard there was a better way by actually entering in the DEL-MAT function into Lisps natural GC methods so it would know when it comes across a function with a new it should call delete to get rid of it when it know i'm done with it.. The thing is I could use help to get started.  Hopefully a concrete example of how to do this so I don't have to call DEL-MAT manually

(dotimes (n 1000) (setf m (mat)) (del-mat m))