anchor.diff:    ((domain :allocation :alien :type quark :reader gerror-domain)
      (code :allocation :alien :type int :reader gerror-code)
      (message :allocation :alien :type string :reader gerror-message))
  -  (:metaclass struct-class))
  +  (:metaclass struct-class)
  +  (:ref gerror-copy)
  +  (:unref gerror-free))
   
   (defbinding (%gerror-copy "g_error_copy") () pointer
     (location pointer))
   
   (defbinding (%gerror-free "g_error_free") () nil
     (location pointer))
  -
  -(defmethod reference-foreign ((class (eql (find-class 'gerror))) location)
  -  (declare (ignore class))
  -  (%gerror-copy location))
  -
  -(defmethod unreference-foreign ((class (eql (find-class 'gerror))) location)
  -  (declare (ignore class))
  -  (%gerror-free location))
  -
   
   (define-condition glib-error (error)
     ((code :initarg :domain :reader gerror-code)
  
positive.code: 
  (deftype gerror-signal () 'gerror)
  
  (define-type-method from-alien-form ((type gerror-signal) gerror)
    (declare (ignore type))
    `(let ((gerror ,(from-alien-form 'gerror gerror)))
       (when gerror
         (signal-gerror gerror))))
  
  
negative.code:     (funcall (if fatal-p #'error #'warn) condition
       :domain domain :message message)))
  
  #-clisp
  (setf 
   #+cmu(alien:extern-alien "log_handler" alien:system-area-pointer) 
   #+sbcl(sb-alien:extern-alien "log_handler" sb-alien:system-area-pointer)
   (callback-address log-handler))
  
  
  #?(pkg-exists-p "glib-2.0" :atleast-version "2.6.0")
  (progn
    ;; Unfortunately this will only work as long as we don't abort to
    ;; toplevel from within the log handler. If we do that, the next
    ;; invocation of g_log will be handled as a recursion and cause an
    ;; abort (SIGABORT being signaled). To make things even worse, SBCL
    ;; doesn't handle SIGABRT at all.
    (defbinding %log-set-default-handler (nil) pointer
      (log-handler callback)
      (nil null))
    (%log-set-default-handler))
  