Hi. I want to use the following C function:
;; void ClearBackground(Color color);
Color is C Struct:
;; typedef struct Color {
;; unsigned char r; // Color red value
;; unsigned char g; // Color green value
;; unsigned char b; // Color blue value
;; unsigned char a; // Color alpha value
;; } Color;
So I wrote:
(cffi:defcstruct %color
(r :uint8)
(g :uint8)
(b :uint8)
(a :uint8))
(defvar *%lightgray* (cffi:foreign-alloc '(:struct %color)))
(cffi:with-foreign-slots ((r g b a) *%lightgray* (:struct %color))
(setf (cffi:foreign-slot-value *%lightgray* '(:struct %color) 'r) 200)
(setf (cffi:foreign-slot-value *%lightgray* '(:struct %color) 'g) 200)
(setf (cffi:foreign-slot-value *%lightgray* '(:struct %color) 'b) 200)
(setf (cffi:foreign-slot-value *%lightgray* '(:struct %color) 'a) 255)
(format t "~s ~s ~s ~s" r g b a))
;; void ClearBackground(Color color);
(cffi:defcfun ("ClearBackground" %clear-background) :void
(color (:struct %color)))
(defun clear-background (color)
(%clear-background color))
But when i run
(clear-background *%lightgray*)
That does not work, I have already added my .asd file ":cffi-libffi" as
dependency.
What is the problem? If this issue has no solution, is there an alternate
way?
