diff --git a/runtime/doc/usr_41.txt b/runtime/doc/usr_41.txt
index 80b7e38..11f035b 100644
--- a/runtime/doc/usr_41.txt
+++ b/runtime/doc/usr_41.txt
@@ -835,6 +835,7 @@
 	screencol()		get screen column of the cursor
 	screenrow()		get screen row of the cursor
 	screenpos()		screen row and col of a text character
+	virtcol2col()		byte index of a text character on screen
 	getcurpos()		get position of the cursor
 	getpos()		get position of cursor, mark, etc.
 	setpos()		set position of cursor, mark, etc.