-typedef gpointer (*VikLayerFuncCopyItem) (VikLayer *, gint, gpointer);
-typedef gboolean (*VikLayerFuncPasteItem) (VikLayer *, gint, gpointer);
+/* item manipulation */
+typedef void (*VikLayerFuncDeleteItem) (VikLayer *, gint, gpointer);
+ /* layer, subtype, pointer to sub-item */
+typedef void (*VikLayerFuncCopyItem) (VikLayer *, gint, gpointer, guint8 **, guint *);
+ /* layer, subtype, pointer to sub-item, return pointer, return len */
+typedef gboolean (*VikLayerFuncPasteItem) (VikLayer *, gint, guint8 *, guint);