ife = lookup_interface(ifname);
ife = lookup_interface(ifname,1);
static int if_print(char *ifname){    int res;     if (!ifname) {	res = for_all_interfaces(do_if_print, &opt_a);    } else {	struct interface *ife;	ife = lookup_interface(ifname);	res = do_if_fetch(ife); 	if (res >= 0) 	    ife_print(ife);    }    return res; }