-typedef gboolean (*GstIteratorFoldFunction) (gpointer item, GValue *ret, gpointer user_data);
-
-/**
- * GstCopyFunction:
- * @object: The object to copy
- *
- * A function to create a copy of some object or
- * increase its reference count.
- *
- * Returns: a copy of the object or the same object with increased reference count
- *
- * Since: 0.10.25
- */
-typedef gpointer (*GstCopyFunction) (gpointer object);
+typedef gboolean (*GstIteratorFoldFunction) (const GValue * item, GValue * ret, gpointer user_data);