diff --git a/calmwm.c b/calmwm.c
index 7fc749b..c146223 100644
--- a/calmwm.c
+++ b/calmwm.c
@@ -220,7 +220,7 @@ sighdlr(int sig)
 	errno = save_errno;
 }
 
-void
+__dead void
 usage(void)
 {
 	extern char	*__progname;
diff --git a/calmwm.h b/calmwm.h
index b51b409..78e5fb0 100644
--- a/calmwm.h
+++ b/calmwm.h
@@ -21,6 +21,14 @@
 #ifndef _CALMWM_H_
 #define _CALMWM_H_
 
+#ifndef __dead
+#ifdef __GNUC__
+#define __dead __attribute__((noreturn))
+#else
+#define __dead
+#endif
+#endif
+
 #include <sys/param.h>
 #include <stdio.h>
 #include "queue.h"
@@ -401,7 +409,7 @@ enum {
 extern Atom				 cwmh[CWMH_NITEMS];
 extern Atom				 ewmh[EWMH_NITEMS];
 
-void			 usage(void);
+__dead void		 usage(void);
 
 void			 client_applysizehints(struct client_ctx *);
 void			 client_config(struct client_ctx *);