diff --git a/src/indent.h b/src/indent.h
index ec6dcaeadf0..9f0c7613ec4 100644
--- a/src/indent.h
+++ b/src/indent.h
@@ -32,3 +32,15 @@ struct position *vmotion ();
 
 /* Value of point when current_column was called */
 extern int last_known_column_point;
+
+/* Functions for dealing with the column cache.  */
+
+/* Return true iff the display table DISPTAB specifies the same widths
+   for characters as WIDTHTAB.  We use this to decide when to
+   invalidate the buffer's column_cache.  */
+extern int disptab_matches_widthtab ( /* struct Lisp_Vector *disptab,
+                                         struct Lisp_Vector *widthtab */ );
+
+/* Recompute BUF's width table, using the display table DISPTAB.  */
+extern void recompute_width_table ( /* struct buffer *buf,
+                                       struct Lisp_Vector *disptab */ );