On Sat, 13 Oct 2007 11:35:40 +0200 "Felip Alàez Nadal" <[EMAIL PROTECTED]> wrote:
> Hello: > > I have a problem with cffi and I don't know if I'm doing something wrong or > if It's a bug. > > ... > > plus a functional interface to create Rect objects: > > Rect app_new_rect(int x , int y , int w , int h ) ; > Hi, it looks like this functions returns Rects by value. If section 13 of the CFFI manual is still up-to-date passing structs by value is not supported by CFFI. > > When I had that problem, I tried to write a Lisp-only function to create > Rect objects , to not use app_new_rect at all. I wrote the next function: > > (defun rect ( x y width height ) > > (cffi:with-foreign-object ( ptr 'rect ) > > (setf (cffi:foreign-slot-value ptr 'rect 'x ) x ) > > (setf (cffi:foreign-slot-value ptr 'rect 'y ) y ) > > (setf (cffi:foreign-slot-value ptr 'rect 'width ) width ) > > (setf (cffi:foreign-slot-value ptr 'rect 'height ) height ) > > ptr > > ) > > ) > The ptr you create in with-foreign-object is only valid in the scope of with-foreign-object, so you shouldn't return it outside like that. Sincerely, Mikael Lax _______________________________________________ cffi-devel mailing list cffi-devel@common-lisp.net http://common-lisp.net/cgi-bin/mailman/listinfo/cffi-devel
