Suppose the Lisp variable
point3
is bound to a FLI pointer as in Creating pointers. To make a copy of the pointer it is not sufficient to do the following:
(setq point4 point3)
This simply sets
point4
to contain the same pointer object as
point3
. Thus if the pointer is changed using
point3
, a similar change is observed when looking in
point4
. To create a distinct copy of the pointer object you should use copy-pointer, which returns a new pointer object with the same address and type as the old one, as the following example shows.
(setq point5 (fli:copy-pointer point3))