gistfile1.cl

(defmacro with-double-ptr ((inner outer c-type) &body body)
  "Creates a pointer INNER (ostensibly of type C-TYPE) which is addressed by OUTER.  Only OUTER is deallocated.
This is intended for use with functions which set take a pointer to a pointer and set the inner pointer's value to the address of some C-TYPE.  Note that no typechecking is done."
  `(let ((,inner (make-pointer 0)))
     (with-foreign-object (,outer '(:pointer ,c-type))
       (setf (mem-ref ,outer :pointer) ,inner)
       ,@body)))

(defmacro with-double-ptr-wfo ((inner outer c-type) &body body)
  "Creates a pointer INNER (ostensibly of type C-TYPE) which is addressed by OUTER."
  `(with-foreign-objects ((,inner ',c-type)
                          (,outer '(:pointer ,c-type)))
     (setf (mem-ref ,outer :pointer) ,inner)
     ,@body))