LB_EVENT_MASK
event = (flags & LB_EVENT_MASK) - 1;
if ((le->le_mask & LB_EVENT_MASK) == 0)
le.le_mask = (eventtype & LB_EVENT_MASK) | (locktype & LB_LOCK_MASK);
(name->mask & LB_EVENT_MASK) != eventtype)
event = (mask & LB_EVENT_MASK) - 1;