[clisp-list] Understanding FFI - Values in Lisp to C

[Berlin B. <ber...@gm...>]

I am working on a small lisp library using FFI, simple question, I am
having trouble getting values that have been loaded in lisp and then
getting them out to a C environment.  For example, here is a
struct(basically a win32 struct) and then I place a variables instance
in a function in let ... but I keep getting clisp 'foreign-values
errors' that say I cant convert from lisp to a foreign-value.

;;;
;;; Author: Berlin Brown
;;;
;;; Date: 12/14/2004
;;;
;;; $Id$
;;;
;;;
;;; Note: FFI:C-PTR is a keyword denoting a pointer of type x
;;;
(defpackage #:widget-toolkit-test
 (:use #:common-lisp #:ffi)
 (:export #:run-test-suite))

;;; define this package
(in-package #:widget-toolkit-test)

(eval-when (compile) (setq FFI:*OUTPUT-C-FUNCTIONS* t))
(default-foreign-language :stdc)

;;;
;;; Member Functions ///
;;;

;;;
;;; Test WNDPROC
;;;
(defun test-wndproc (hwnd message wparam lparam)
 (declare (type ffi:c-pointer hwnd))
 (declare (type ffi:uint message))
 (declare (type ffi:long lparam))
 ;;; return ;;;
 (let ((lresult -1))
   (declare (type long lresult))
   lresult))

;;;
;;; WNDCLASSEX
;;; note: typedef CONST CHAR *LPCCH,*PCSTR,*LPCSTR;
;;;
;;; typedef WORD *PWORD,*LPWORD, whenever you
;;; see PWORD = WORD*
;;;
;;;
;;; invalid: (b (c-pointer (c-function
;;; invalid:   (:arguments (v int))) d))
;;;
(def-c-struct test-wndclassex
 (cbSize uint)
 (style uint)
 (lpfnWndProc
  (c-function (:arguments
               (hwnd ffi:c-pointer)
               (message ffi:uint)
               (lparam ffi:uint))
              (:language :stdc)
              (:return-type ffi:long)))
 (cbClsExtra int)
 (cbWndExtra int)
 (hInstance c-pointer)
 (hIcon c-pointer)
 (hCursor c-pointer)
 (hbrBackground c-pointer)
 (lpszMenuName c-string)
 (lpszClassName c-string)
 (hIconSm c-pointer))

;;;
;;; DLLIMPORT unsigned int WidgetSizeofWND();
;;; DLLIMPORT void* WidgetDefaultIcon();
;;; DLLIMPORT void* WidgetDefaultCursor();
;;; DLLIMPORT void* WidgetDefaultBrush();
;;;
;;; Default Widget Create Handles:
;;;
(def-call-out widget-testpointer
 (:name "TestPointer")
 (:arguments (lisp-wndclass-ptr (c-ptr test-wndclassex)))
 (:return-type)
 (:library "WidgetToolkit.dll"))

(def-call-out widget-sizeof-wnd
 (:name "WidgetSizeofWND")
 (:arguments)
 (:return-type ffi:c-pointer)
 (:library "WidgetToolkit.dll"))

(def-call-out widget-defaulticon
 (:name "WidgetDefaultIcon")
 (:arguments)
 (:return-type ffi:c-pointer)
 (:library "WidgetToolkit.dll"))

(def-call-out widget-defaultcursor
 (:name "WidgetDefaultCursor")
 (:arguments)
 (:return-type ffi:c-pointer)
 (:library "WidgetToolkit.dll"))

(def-call-out widget-defaultbrush
 (:name "WidgetDefaultBrush")
 (:arguments)
 (:return-type ffi:c-pointer)
 (:library "WidgetToolkit.dll"))

;;;
;;; Run the set of tests
;;;
(defun run-test-suite ()
 (print "/// test suite begin .....")
 (let ((wnd
        (make-test-wndclassex
         :cbSize (widget-sizeof-wnd)
         :style 0
         :lpfnWndProc #'test-wndproc
         :cbClsExtra 0
         :cbWndExtra 0
         :hInstance nil
         :hIcon (widget-defaulticon)
         :hCursor (widget-defaultcursor)
         :hbrBackground (widget-defaultbrush)
         :lpszMenuName "NONE"
         :lpszClassName "gClassName"
         :hIconSm (widget-defaulticon)
        )))
   ;;(print (slot-value wnd 'cbSize))
   ;;(print (slot-value wnd 'hIcon))
   (def-c-var aa (
                  :type (c-ptr test-wndclassex)))
   ;;(widget-testpointer aa)
   ;;;(ffi:c-var-address wnd)

;;;
;;; Problem Area here!!!!!!!!!!!!!!!!!!!!!!!!!!!1111

   )
 ;;; Exit
 (print "..... test suite end ///"))

(provide "widget-toolkit-test")

;;;
;;; End of File
;;;