#lang racket (require ffi/unsafe ffi/vector rackunit) (define lib (ffi-lib "reader.dylib")) (define-struct info (a b c)) (define my-info (make-info 12 13 14)) (define info-holder (malloc-immobile-cell my-info)) (define info-holder-ptr (ptr-ref info-holder _racket)) (define find-elements (get-ffi-obj "findElements" lib (_fun _racket _racket -> _ulong))) (eq? info-holder-ptr my-info) (find-elements info-holder-ptr info-holder)