Happy new year! On 64-bit Allegro, run (cffi:defcfun strerror :string (errnum :int)) (strerror 1) and you will probably get Received signal number 4 (Illegal instruction) [Condition of type EXCL:SYNCHRONOUS-OPERATING-SYSTEM-SIGNAL] at least if the returned pointer is more than 32-bits. The problem is that without this patch, cffi-allegro.lisp does not support 64-bit pointers. Does the patch address the problem properly? It seems to work for us. The use of :unsigned-nat instead of :unsigned-long is recommended by Franz because on Windows 64-bit :unsigned-long is still 32-bits. --- a/addons/cffi_0.10.3/src/cffi-allegro.lisp +++ b/addons/cffi_0.10.3/src/cffi-allegro.lisp @@ -135,7 +135,7 @@ SIZE-VAR is supplied, it will be bound to SIZE during BODY." ;; stack allocation pattern `(let ((,size-var ,size)) (declare (ignorable ,size-var)) - (ff:with-stack-fobject (,var '(:array :char ,size)) + (ff:with-stack-fobject (,var '(:array :char ,size) :allocation :foreign-static-gc) (let ((,var (ff:fslot-address ,var))) ;; (excl::stack-allocated-p var) => T ,@body)))) @@ -263,12 +263,12 @@ SIZE-VAR is supplied, it will be bound to SIZE during BODY." :unsigned-long) 'integer) (:float 'single-float) (:double 'double-float) - (:foreign-address :foreign-address) + (:foreign-address 'integer) (:void 'null)))) (defun foreign-allegro-type (type) (if (eq type :foreign-address) - nil + :unsigned-nat type)) (defun allegro-type-pair (type)