Hi again, here's another easy to add thing to add (which I already suggested month ago, I could submit a patch instead, but I haven't updated cffi recently): o provide and export a type declaration name for people who wish to add :type information to structs, slots or bindings. E.g. for CLISP: (deftype cffi-pointer (or ffi:foreign-address null)) ;also ffi:foreign-variable? ffi:foreign-function? Regards, Jörg Höhle.