I am encountering some problems with trying to upgrade my old cffi code to the new version from quicklisp. If I use the old code, I get lots of warnings about my structs, that I should use either (:struct ...) or (:pointer (:struct ...)) However whateer I try, I do not seem to get it to work, and I am starting to think there is some issue between me and the new cffi. The main issue is a nested struct definition like this: ``` (defcstruct timeval (time %time) (offset :int)) (defcstruct (git-signature) (name :string) (email :string) (time (:struct timeval))) ``` With type definitions ``` (define-foreign-type time-type () nil (:actual-type :int64) (:simple-parser %time)) (define-foreign-type git-signature-type () nil (:actual-type :pointer) (:simple-parser %git-signature)) ``` I encounter problems when I am trying to update the `translate-to-foreign` for the `git-signature-type`. The implementation boils down to: ``` (defmethod translate-to-foreign ((value list) (type git-signature-type)) (let ((signature (foreign-alloc '(:struct git-signature)))) (with-foreign-slots ((name email time) signature (:struct git-signature)) (setf name (getf value :name (getenv "USER"))) (setf email (getf value :email (default-email))) (with-foreign-slots ((time offset) time (:struct timeval)) (let ((time-to-set (getf value :time (local-time:now)))) (setf time time-to-set) (setf offset (/ (local-time:timestamp-subtimezone time-to-set local-time:*default-timezone*) 60))))) signature) ``` The problem is in the inner `with-foreign-slots ((time offset)...`. The error I get is: ; Evaluation aborted on #<TYPE-ERROR expected-type: SYSTEM-AREA-POINTER datum: (CL-GIT::OFFSET 0 TIME @1970-01-01T01:00:03.000000+01:00)>. The reason is, as far as I can tell, that in the code: (with-foreign-slots ((time offset) time (:struct timeval)) ... the value of `time` is already a plist (due to the outer with-foreign-slots), and the inner with-foreign-slots expects a pointer. So what is the best way of fixing this? I can fix this by replacing the inner `with-foreign-slots` by ``` (with-foreign-slots ((time offset) (foreign-slot-pointer signature '(:struct git-signature) 'time) (:struct timeval)) ``` which seems a bit long. An additional question is, when to use (:struct ...) and when to use (:pointer (:struct ..))) I did expect that I needed to use (:pointer (:struct ..)) in the toplevel `with-foreign-slots`, because the argument is actually a pointer to the struct. But that did not work. As you can tell, I am a bit confused. Hope that someone can give some hints to clear my head. Kind regards, Wim Oudshoorn.