diff --git a/src/structs.h b/src/structs.h
index 36b0870..a95e1ba 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -327,7 +327,8 @@
     visualinfo_T uh_visual;	/* Visual areas before undo/after redo */
 #endif
     time_t	uh_time;	/* timestamp when the change was made */
-    long_u	uh_save_nr;	/* counter for last time saved */
+    long	uh_save_nr;	/* set when the file was saved after the
+				   changes in this block */
 #ifdef U_DEBUG
     int		uh_magic;	/* magic number to check allocation */
 #endif
@@ -1371,9 +1372,10 @@
     int		b_u_numhead;	/* current number of headers */
     int		b_u_synced;	/* entry lists are synced */
     long	b_u_seq_last;	/* last used undo sequence number */
+    long	b_u_save_nr_last; /* counter for last file write */
     long	b_u_seq_cur;	/* hu_seq of header below which we are now */
     time_t	b_u_time_cur;	/* uh_time of header below which we are now */
-    long_u	b_u_last_save_nr; /* counter for last file write */
+    long	b_u_save_nr_cur; /* file write nr after which we are now */
 
     /*
      * variables for "U" command in undo.c