ZS_IS_OPEN
if (ZS_IS_OPEN(uap))
if (ZS_IS_OPEN(uap) && ZS_WANTS_MODEM_STATUS(uap)) {
if (!ZS_IS_OPEN(uap))
if (!ZS_IS_OPEN(uap_a)) {
if (!ZS_IS_OPEN(uap_b)) {
if (!(ZS_IS_OPEN(uap) || ZS_IS_CONS(uap)))