AS_ALL_EVENT
error = as_add_callback(as, umem_lock_undo, p, AS_ALL_EVENT,
if ((cb_func == NULL) || ((events & AS_ALL_EVENT) == 0))
cb->ascb_events &= ~AS_ALL_EVENT;
while (as->a_callbacks && as_do_callbacks(as, AS_ALL_EVENT, 0, 0))