Hello, i'am using the CFFI on 32-bit machines without any problem. Switching to a 64-bit platform breaks the loading of a lib. uname -a: Linux master 2.6.8-24-smp #1 SMP Wed Oct 6 09:16:23 UTC 2004 x86_64 x86_64 x86_64 GNU/Linux /etc/SuSE-release: SuSE Linux 9.2 (x86-64) VERSION = 9.2 sbcl: SBCL 0.9.11 library: libgslcblas.so.0 (libc6,x86-64) => /usr/lib/libgslcblas.so.0 libgslcblas.so (libc6,x86-64) => /usr/lib/libgslcblas.so libgsl.so.0 (libc6,x86-64) => /usr/lib/libgsl.so.0 libgsl.so (libc6,x86-64) => /usr/lib/libgsl.so ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; The small lisp prog: (defpackage :cffi-user (:use :common-lisp :cffi)) (in-package :cffi-user) (pushnew #P"/usr/local/lib/" *foreign-library-directories* :test #'equal) ; alternative 1 (define-foreign-library libgslcblas (:unix (:or "libgslcblas.so.0.0.0" "libgslcblas.so.0")) (t (:default "libgslcblas"))) ; alternative 2 (define-foreign-library libgslcblas (t (:default "libgslcblas"))) (use-foreign-library libgslcblas) <---the error happens here (define-foreign-library libgsl (:unix (:or "libgsl.so.0.9.0" "libgsl.so.0")) (t (:default "libgsl"))) (use-foreign-library libgsl) ;;;; (defcfun "gsl_sf_bessel_J0" :double (x :double)) (time (format t "~A~%" (gsl-sf-bessel-J0 5d0))) ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; END The error message: Unable to load foreign library: libgslcblas.so [Condition of type LOAD-FOREIGN-LIBRARY-ERROR] 0: (CFFI::HANDLE-LOAD-FOREIGN-LIBRARY-ERROR "libgslcblas.so" "Unable to load foreign library: ~A" "libgslcblas.so") It doesn't matter if i use alternative 1 or 2. Is it a general matter that CFFI cannot handle 64-bit libs ? Regards Heiko