If you have followed this example from the beginning, the interface and its callbacks are now completely specified. Next, you can create a Common Lisp system which integrates the interface definition with the callback code.
(defsystem ib-test
(:package "CL-USER")
:members ("ib-callbacks" "ib-example"))
This form creates a system called
ib-test
that contains two members;
ib-example.lisp
(the file containing the interface definition) and
ib-callbacks.lisp
(the file containing the callback code).
ib-example.lisp
and
ib-callbacks.lisp
files, and call this file
defsys.lisp
.