-static void print_attr_string(netdissect_options *, register u_char *, u_int, u_short );
-static void print_attr_num(netdissect_options *, register u_char *, u_int, u_short );
-static void print_vendor_attr(netdissect_options *, register u_char *, u_int, u_short );
-static void print_attr_address(netdissect_options *, register u_char *, u_int, u_short);
-static void print_attr_time(netdissect_options *, register u_char *, u_int, u_short);
-static void print_attr_strange(netdissect_options *, register u_char *, u_int, u_short);
+static void print_attr_string(netdissect_options *, register const u_char *, u_int, u_short );
+static void print_attr_num(netdissect_options *, register const u_char *, u_int, u_short );
+static void print_vendor_attr(netdissect_options *, register const u_char *, u_int, u_short );
+static void print_attr_address(netdissect_options *, register const u_char *, u_int, u_short);
+static void print_attr_time(netdissect_options *, register const u_char *, u_int, u_short);
+static void print_attr_strange(netdissect_options *, register const u_char *, u_int, u_short);