diff -r 567bb019e3e3 -r 7e817e7e631c gstreamer_core/gst/gstinterface.h
--- a/gstreamer_core/gst/gstinterface.h	Tue Aug 31 15:30:33 2010 +0300
+++ b/gstreamer_core/gst/gstinterface.h	Wed Sep 01 12:16:41 2010 +0100
@@ -32,8 +32,13 @@
 #define GST_IMPLEMENTS_INTERFACE(obj) \
   (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_IMPLEMENTS_INTERFACE, \
 				      GstImplementsInterface))
+#define GST_IMPLEMENTS_INTERFACE_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_IMPLEMENTS_INTERFACE, \
+			    GstImplementsInterfaceClass))
 #define GST_IS_IMPLEMENTS_INTERFACE(obj) \
   (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_IMPLEMENTS_INTERFACE))
+#define GST_IS_IMPLEMENTS_INTERFACE_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_IMPLEMENTS_INTERFACE))
 #define GST_IMPLEMENTS_INTERFACE_GET_CLASS(inst) \
   (G_TYPE_INSTANCE_GET_INTERFACE ((inst), GST_TYPE_IMPLEMENTS_INTERFACE, \
 				  GstImplementsInterfaceClass))