anchor.diff:  ;;------------------------------------------------------------
   ;; newtoncorkscrewcallback
   
  -(defcallback %corkscrew-cb :void
  +(defcallback %corkscrew-cb :uint
       ((joint-ptr :pointer)
        (data (:pointer NewtonHingeSliderUpdateDesc)))
     (with-foreign-slots ((m-accel m-minFriction m-maxFriction m-timestep)
  
positive.code: ;;------------------------------------------------------------
  ;; newtonslidercallback
  
  (defcallback %slider-cb :void
      ((joint-ptr :pointer)
       (data (:pointer NewtonHingeSliderUpdateDesc)))
    (with-foreign-slots ((m-accel m-minFriction m-maxFriction m-timestep)
  
negative.code: ;;------------------------------------------------------------
  ;; newtonhingecallback
  
  (defcallback %hinge-cb :uint
      ((joint-ptr :pointer)
       (data (:pointer NewtonHingeSliderUpdateDesc)))
    (with-foreign-slots ((m-accel m-minFriction m-maxFriction m-timestep)
  