diff --git a/include/irc.h b/include/irc.h
index b3829ff..f17d31c 100644
--- a/include/irc.h
+++ b/include/irc.h
@@ -254,14 +254,14 @@ extern	char	space_minus[];
 extern	char	dot[];
 extern	char	star[];
 extern	char	comma[];
-extern	char	nickname[];
+extern	char	nickname[NICKNAME_LEN + 1];
 extern	char	*ircrc_file;
 extern	char	*bircrc_file;
 extern	char	*LocalHostName;
-extern	char	hostname[];
-extern	char	userhost[];
-extern	char	realname[];
-extern	char	username[];
+extern	char	hostname[NAME_LEN + 1];
+extern	char	userhost[(NAME_LEN + 1) * 2];
+extern	char	realname[REALNAME_LEN + 1];
+extern	char	username[NAME_LEN + 1];
 extern	char	*send_umode;
 extern	char	*last_notify_nick;
 extern	int	away_set;