--- modules/FvwmAuto/FvwmAuto.c.orig
+++ modules/FvwmAuto/FvwmAuto.c
@@ -340,6 +340,8 @@ main(int argc, char **argv)
 	{
 		len = max(len, strlen(leave_fn));
 	}
+	/* add space for newline and trailing 0 */
+	len += 2;
 	if (do_pass_id)
 	{
 		len += 32;