-extern Canvas::Handle open_canvas(const String &filename,String &errors);
-extern Canvas::Handle open_canvas_as(const String &filename,const String &as,String &errors);
+extern Canvas::Handle open_canvas(xmlpp::Element* node,String &errors,String &warnings);
+extern Canvas::Handle open_canvas(const String &filename,String &errors,String &warnings);
+extern Canvas::Handle open_canvas_as(const String &filename,const String &as,String &errors,String &warnings);