diff --git a/sbin/dump/dump.h b/sbin/dump/dump.h
index b41ffda95f98..c1b1302ebf0a 100644
--- a/sbin/dump/dump.h
+++ b/sbin/dump/dump.h
@@ -96,10 +96,10 @@ int	tp_bshift;	/* log2(TP_BSIZE) */
 /* operator interface functions */
 void	broadcast __P((char *message));
 void	lastdump __P((int arg));	/* int should be char */
-void	msg __P((const char *fmt, ...));
-void	msgtail __P((const char *fmt, ...));
+void	msg __P((const char *fmt, ...)) __printflike(1, 2);
+void	msgtail __P((const char *fmt, ...)) __printflike(1, 2);
 int	query __P((char *question));
-void	quit __P((const char *fmt, ...));
+void	quit __P((const char *fmt, ...)) __printflike(1, 2);
 void	set_operators __P((void));
 void	timeest __P((void));
 time_t	unctime __P((char *str));