diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index 6a5ec1b..661876b 100644
--- a/runtime/doc/builtin.txt
+++ b/runtime/doc/builtin.txt
@@ -713,7 +713,8 @@
 utf16idx({string}, {idx} [, {countcc} [, {charidx}]])
 				Number	UTF-16 index of byte {idx} in {string}
 values({dict})			List	values in {dict}
-virtcol({expr} [, {list}])	Number or List
+virtcol({expr} [, {list} [, {winid}])
+				Number or List
 					screen column of cursor or mark
 virtcol2col({winid}, {lnum}, {col})
 				Number  byte index of a character on screen
@@ -10283,7 +10284,7 @@
 		Can also be used as a |method|: >
 			mydict->values()
 
-virtcol({expr} [, {list}])				*virtcol()*
+virtcol({expr} [, {list} [, {winid}]])			*virtcol()*
 		The result is a Number, which is the screen column of the file
 		position given with {expr}.  That is, the last screen position
 		occupied by the character at that position, when the screen
@@ -10315,10 +10316,13 @@
 			    returns the cursor position.  Differs from |'<| in
 			    that it's updated right away.
 
-		If {list} is present and non-zero then virtcol() returns a List
-		with the first and last screen position occupied by the
+		If {list} is present and non-zero then virtcol() returns a
+		List with the first and last screen position occupied by the
 		character.
 
+		With the optional {winid} argument the values are obtained for
+		that window instead of the current window.
+
 		Note that only marks in the current file can be used.
 		Examples: >
 			" With text "foo^Lbar" and cursor on the "^L":
@@ -10330,7 +10334,7 @@
 			" With text "	  there", with 't at 'h':
 
 			virtcol("'t")	" returns 6
-<		The first column is 1.  0 is returned for an error.
+<		The first column is 1.  0 or [0, 0] is returned for an error.
 		A more advanced example that echoes the maximum length of
 		all lines: >
 		    echo max(map(range(1, line('$')), "virtcol([v:val, '$'])"))