diff --git a/src/structs.h b/src/structs.h
index b3b3f6a..47a0050 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -802,8 +802,8 @@
 #define ML_ALLOCATED	0x10	// ml_line_ptr is an allocated copy
     int		ml_flags;
 
-    colnr_T	ml_line_len;	// length of the cached line + textproperties, including NUL
-    colnr_T	ml_line_textlen;// length of the cached line, including NUL
+    colnr_T	ml_line_len;	// length of the cached line + NUL + text properties
+    colnr_T	ml_line_textlen;// length of the cached line + NUL, 0 if not known yet
     linenr_T	ml_line_lnum;	// line number of cached line, 0 if not valid
     char_u	*ml_line_ptr;	// pointer to cached line