(let ((orig (uffi:get-slot-value *fvar-struct* 'fvar-struct 'i)))
(decf (uffi:get-slot-value *fvar-struct* 'fvar-struct 'i) 10)
(prog1
(let ((orig (uffi:get-slot-value *fvar-struct* 'fvar-struct 'i)))
(decf (uffi:get-slot-value *fvar-struct* 'fvar-struct 'i) 10)
(prog1