rb_if_indextoname  727 ext/socket/option.c         rb_if_indextoname(" ", " ifindex:", s.imr_ifindex, ifbuf, sizeof(ifbuf));
rb_if_indextoname  783 ext/socket/option.c         rb_if_indextoname(" ", " ", ifindex, ifbuf, sizeof(ifbuf));
rb_if_indextoname  805 ext/socket/option.c         rb_if_indextoname(" ", " interface:", s.ipv6mr_interface, ifbuf, sizeof(ifbuf));