===================================================================
RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/cvs/diff3.c,v
retrieving revision 1.64
retrieving revision 1.65
diff -u -r1.64 -r1.65
--- src/usr.bin/cvs/diff3.c	2020/06/26 07:28:47	1.64
+++ src/usr.bin/cvs/diff3.c	2021/04/13 14:20:23	1.65
@@ -1,4 +1,4 @@
-/*	$OpenBSD: diff3.c,v 1.64 2020/06/26 07:28:47 stsp Exp $	*/
+/*	$OpenBSD: diff3.c,v 1.65 2021/04/13 14:20:23 stsp Exp $	*/
 
 /*
  * Copyright (C) Caldera International Inc.  2001-2002.
@@ -743,6 +743,8 @@
 		do {
 			c = getc(fp[0]);
 			d = getc(fp[1]);
+			if (c == -1 && d == -1)
+				break;
 			if (c == -1 || d== -1)
 				return (-1);
 			nchar++;