diff --git a/src/globals.h b/src/globals.h
index 6f2a1a5..786c850 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -32,15 +32,17 @@
  * The characters that are currently on the screen are kept in ScreenLines[].
  * It is a single block of characters, the size of the screen plus one line.
  * The attributes for those characters are kept in ScreenAttrs[].
+ * The byte offset in the line is kept in ScreenCols[].
  *
  * "LineOffset[n]" is the offset from ScreenLines[] for the start of line 'n'.
- * The same value is used for ScreenLinesUC[] and ScreenAttrs[].
+ * The same value is used for ScreenLinesUC[], ScreenAttrs[] and ScreenCols[].
  *
  * Note: before the screen is initialized and when out of memory these can be
  * NULL.
  */
 EXTERN schar_T	*ScreenLines INIT(= NULL);
 EXTERN sattr_T	*ScreenAttrs INIT(= NULL);
+EXTERN colnr_T  *ScreenCols INIT(= NULL);
 EXTERN unsigned	*LineOffset INIT(= NULL);
 EXTERN char_u	*LineWraps INIT(= NULL);	// line wraps to next line
 
@@ -62,7 +64,7 @@
 EXTERN schar_T	*ScreenLines2 INIT(= NULL);
 
 /*
- * Buffer for one screen line (characters and attributes).
+ * One screen line to be displayed.  Points into ScreenLines.
  */
 EXTERN schar_T	*current_ScreenLine INIT(= NULL);