kevent
int kevent(int kq, const struct kevent *changelist, int nchanges,
struct kevent *eventlist, int nevents,
*(kevp_) = (struct kevent){ \
struct kevent *kevp = (kevp_); \
const struct kevent *changelist, int nchanges,
struct kevent *eventlist, int nevents,
struct kevent kv;
n = kevent(kq, &kv, 1, &kv, 1, &timeout);