diff -u -p a/notice/notice.c b/notice/notice.c
--- a/notice/notice.c
+++ b/notice/notice.c
@@ -137,14 +137,14 @@ parse_opt (int key, char *arg, struct ar
 	/* Open the file.  */
 	file = file_name_lookup (arg, 0, 0);
 	if (file == MACH_PORT_NULL)
-	  error (1, errno, "Could not open %s", arg);
+	  argp_error(state, arg);
 
 	/* Create the notification port.  */
 	err = ports_create_port (class, bucket,
 				 sizeof (struct notice_handle) + strlen (arg),
 				 &notice);
 	if (err)
-	  error (1, err, "Could not allocate port");
+	  argp_error(state, "Could not allocate port");
 	/* Record the file name and the changes we are interested in.  */
 	strcpy (notice->name, arg);
 	notice->changes = changes;
@@ -153,7 +153,7 @@ parse_opt (int key, char *arg, struct ar
 	err = file_notice_changes (file, ports_get_right (notice),
 				   MACH_MSG_TYPE_MAKE_SEND);
 	if (err)
-	  error (1, err, "Noticing changes not possible for %s", arg);
+	  argp_error(state, arg);
 	break;
       }