Pointers and Boxes

C++ prototype:

 
   /* a wxWindow method */
   void ClientToScreen(int *x, int *y); 

Scheme use:

 
   (let ([x-box (box 10)]
         [y-box (box 10)])
      (send my-wind client-to-screen x-box y-box)
      (let ([x (unbox x-box)]
            [y (unbox y-box)])
         ...)))