here is the scenario: (defpackage :lispverse (:use :common-lisp :cffi)) (in-package :lispverse) (define-foreign-library libverse (:unix (:or "/home/deepfire/source/% EXTRN/uni-verse/=src/verse/libverse.so")) (t (:default "libverse"))) (use-foreign-library libverse) (let ((foreign-ptr (foreign-symbol-pointer "verse_send_connect_accept" :code))) (format t "foreign-ptr contents: ") (dotimes (i 16) (format t "~2,'0X " (the (unsigned-byte 8) (mem-ref foreign-ptr :uint8 i)))) (format t "~%")) This code gives different printouts on CLISP/CMUCL/SBCL backends: CLISP: foreign-ptr contents: 55 89 E5 83 EC 28 8B 45 0C 89 44 24 04 8D 45 F8 CMUCL: foreign-ptr contents: E9 26 AE C3 F9 90 00 00 00 00 00 00 00 00 00 00 SBCL: foreign-ptr contents: E9 CE A2 A1 47 90 00 00 00 00 00 00 00 00 00 00 This amounts to foreign-symbol-pointer finding different things on different lisps, in the same shared library. The CLISP way appears to be correct, according to objdump: 0001a43b <verse_send_connect_accept>: 1a43b: 55 push %ebp 1a43c: 89 e5 mov %esp,%ebp 1a43e: 83 ec 28 sub $0x28,%esp 1a441: 8b 45 0c mov 0xc(%ebp),%eax 1a444: 89 44 24 04 mov %eax,0x4(%esp) 1a448: 8d 45 f8 lea 0xfffffff8(%ebp),%eax 1a44b: 89 04 24 mov %eax,(%esp) ... libverse.so is attached. regards, Samium Gromoff