diff --git a/lib/libutil/libutil.h b/lib/libutil/libutil.h
index 1bb4b9fd564..18fb83ff98c 100644
--- a/lib/libutil/libutil.h
+++ b/lib/libutil/libutil.h
@@ -47,7 +47,7 @@ struct in_addr;
 __BEGIN_DECLS
 void	login __P((struct utmp *_ut));
 int	login_tty __P((int _fd));
-int	logout __P((char *_line));
+int	logout __P((const char *_line));
 void	logwtmp __P((const char *_line, const char *_name, const char *_host));
 void	trimdomain __P((char *_fullhost, int _hostsize));
 int	openpty __P((int *_amaster, int *_aslave, char *_name,
diff --git a/lib/libutil/logout.c b/lib/libutil/logout.c
index 5b9a821b60d..c0bd85983f1 100644
--- a/lib/libutil/logout.c
+++ b/lib/libutil/logout.c
@@ -54,9 +54,9 @@ typedef struct utmp UTMP;
 
 int
 logout(line)
-	register char *line;
+	const char *line;
 {
-	register int fd;
+	int fd;
 	UTMP ut;
 	int rval;