ev_cb_
#define ev_cb(ev) (memmove (&ev_cb_ (ev), &((ev_watcher *)(ev))->cb, sizeof (ev_cb_ (ev))), (ev)->cb)
# define ev_set_cb(ev,cb_) (ev_cb_ (ev) = (cb_), memmove (&((ev_watcher *)(ev))->cb, &ev_cb_ (ev), sizeof (ev_cb_ (ev))))
