Thank you for all your work and the time to answer my questions.
Liam Healy lnp@healy.washington.dc.us writes:
Willem,
Thanks for the report.
My thinking is that with-foreign-slots is intended to expose the value (and not the pointer), and therefore, expands to foreign-slot-value, so the behavior you're seeing is correct. Your fix to your code is the correct way to access the pointer. I think with-foreign-slots is provided as a convenient shortcut to get all the values; since it doesn't do what you need, you need to use the actual access form (foreign-slot-pointer in your case).
Ah, ok, I am a bit struggling to convert the old way to the new way. It probably has nothing to do with (with-foreign-slots ...), but just my mis understanding and trying to quickly convert old code to new.
For your second question: if the argument is actually a pointer to the structure, :pointer is the right thing to use. Are you sure it is a pointer argument? Check the .h file where it is defined.
Liam
Ah, I do not have an issue with passing it to the c library. What I meant was that in my mind the following confused me:
(let ((c-oid (foreing-alloc '(:struct git-oid)))) ;;; I think of c-oid, conceptually as type ;;; (:pointer (:struct git-oid)) ;;;; later:
(foreign-slot-pointer c-oid '(:struct git-oid) 'id) ;;; I thought that because c-oid is of type ;;; (:pointer (:struct git-oid)) ;;; I thought I needed to put here ;;; '(:pointer (:struct git-oid)) instead of ;;; '(:struct git-oid)
Does this make sense?
Now I have a small additional question.
I have a struct like:
(defcstruct (git-index-time :class index-time-struct) ....)
Now the (translate-from-foreign value (type index-time-struct)) works if I use as type:
(:struct git-index-time)
So everyting works. However, if I do:
(defctype struct-index-time (:struct git-index-time))
And use as type:
struct-index-time
The `translate-from-foreign` is not called and I end up with untranslated values.
I thought that (defctype ...) worked as a typedef and naively expected the type translation to still work.
Is this as expected?
I probably should use (define-parse-method ...) to get the behaviour as I expect. Hm, some more digging to do.
Kind regards, Wim Oudshoorn.