--- a/vapi/gobject-introspection-1.0.vapi
+++ b/vapi/gobject-introspection-1.0.vapi
@@ -39,7 +39,7 @@ namespace GI {
                [CCode (cname = "g_base_info_is_deprecated")]
                public bool is_deprecated ();
                [CCode (cname = "g_base_info_iterate_attributes")]
-               public bool iterate_attributes (GI.AttributeIter iterator, out unowned string name, out unowned string value);
+               public bool iterate_attributes (ref GI.AttributeIter iterator, out unowned string name, out unowned string value);
        }
        [CCode (cheader_filename = "girepository.h")]
        public class CallableInfo : GI.BaseInfo {

