anchor.diff:  ;; TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
   ;; SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
   
  -;; $Id: gcallback.lisp,v 1.45 2007-06-25 13:49:05 espen Exp $
  +;; $Id: gcallback.lisp,v 1.46 2007-08-20 11:15:13 espen Exp $
   
   (in-package "GLIB")
   
  
positive.code: 	  (disconnect () :report "Disconnect and exit signal handler"
  	    (when (signal-handler-is-connected-p instance handler-id)
  	      (signal-handler-disconnect instance handler-id))
  	    (values nil t))))
        (when (signal-handler-is-connected-p instance handler-id)
  	(signal-handler-unblock instance handler-id))))
  
  (defun invoke-callback (callback-id return-type &rest args)
    (restart-case (apply (find-user-data callback-id) args)
  
negative.code: (defun register-callback-function (function)
    (check-type function (or null symbol function))
    (register-user-data function))
  
  (deftype user-callback () '(or function symbol))
  
  (define-type-method alien-type ((type user-callback))
    (declare (ignore type))
    (alien-type 'pointer-data))
  
  (define-type-method to-alien-form ((type user-callback) func &optional copy-p)
    (declare (ignore type copy-p))
    `(register-callback-function ,func))
  
  
  ;; Callback marshaller for regular signal handlers
  (define-callback signal-handler-marshal nil
  