diff --git a/mkpasswd.c b/mkpasswd.c
index 8066c81..5b31ddc 100644
--- a/mkpasswd.c
+++ b/mkpasswd.c
@@ -124,7 +124,7 @@ static const struct crypt_method methods[] = {
 
 void generate_salt(char *const buf, const unsigned int len);
 void *get_random_bytes(const unsigned int len);
-void display_help(int error);
+void NORETURN display_help(int error);
 void display_version(void);
 void display_methods(void);
 
@@ -438,7 +438,7 @@ void generate_salt(char *const buf, const unsigned int len)
 
 #endif /* RANDOM_DEVICE || HAVE_ARC4RANDOM_BUF */
 
-void display_help(int error)
+void NORETURN display_help(int error)
 {
     fprintf((EXIT_SUCCESS == error) ? stdout : stderr,
 	    _("Usage: mkpasswd [OPTIONS]... [PASSWORD [SALT]]\n"
diff --git a/utils.c b/utils.c
index e29749e..4ade650 100644
--- a/utils.c
+++ b/utils.c
@@ -73,7 +73,7 @@ char **merge_args(char *args, char *argv[], int *argc)
 }
 
 /* Error routines */
-void err_sys(const char *fmt, ...)
+void NORETURN err_sys(const char *fmt, ...)
 {
     va_list ap;
 
@@ -84,7 +84,7 @@ void err_sys(const char *fmt, ...)
     exit(2);
 }
 
-void err_quit(const char *fmt, ...)
+void NORETURN err_quit(const char *fmt, ...)
 {
     va_list ap;
 
diff --git a/utils.h b/utils.h
index 4523266..3266324 100644
--- a/utils.h
+++ b/utils.h
@@ -54,7 +54,7 @@
 void *do_nofail(void *ptr, const char *file, const int line);
 char **merge_args(char *args, char *argv[], int *argc);
 
-void err_quit(const char *fmt, ...) NORETURN;
-void err_sys(const char *fmt, ...) NORETURN;
+void NORETURN err_quit(const char *fmt, ...);
+void NORETURN err_sys(const char *fmt, ...);
 
 #endif
diff --git a/whois.c b/whois.c
index 897a7ed..adcf5e7 100644
--- a/whois.c
+++ b/whois.c
@@ -1051,13 +1051,13 @@ int connect_with_timeout(int fd, const struct sockaddr *addr,
     return 0;
 }
 
-void alarm_handler(int signum)
+void NORETURN alarm_handler(int signum)
 {
     close(sockfd);
     err_quit(_("Timeout."));
 }
 
-void sighandler(int signum)
+void NORETURN sighandler(int signum)
 {
     close(sockfd);
     err_quit(_("Interrupted by signal %d..."), signum);
@@ -1379,7 +1379,7 @@ int isasciidigit(const char c) {
 
 /* http://www.ripe.net/ripe/docs/databaseref-manual.html */
 
-void usage(int error)
+void NORETURN usage(int error)
 {
     fprintf((EXIT_SUCCESS == error) ? stdout : stderr, _(
 "Usage: whois [OPTION]... OBJECT...\n\n"
diff --git a/whois.h b/whois.h
index b384152..a33a241 100644
--- a/whois.h
+++ b/whois.h
@@ -1,3 +1,5 @@
+#include "utils.h"
+
 /* 6bone referto: extension */
 #define REFERTO_FORMAT	"%% referto: whois -h %255s -p %15s %1021[^\n\r]"
 
@@ -21,9 +23,9 @@ char *query_crsnic(const int, const char *);
 char *query_afilias(const int, const char *);
 int openconn(const char *, const char *);
 int connect_with_timeout(int, const struct sockaddr *, socklen_t, int);
-void usage(int error);
-void alarm_handler(int);
-void sighandler(int);
+void NORETURN usage(int error);
+void NORETURN alarm_handler(int);
+void NORETURN sighandler(int);
 int japanese_locale(void);
 unsigned long myinet_aton(const char *);
 unsigned long asn32_to_long(const char *);