+/* convinience function, wait for a single event, without registering an event watcher */
+/* if timeout is < 0, do wait indefinitely */
+void ev_once (EV_P_ int fd, int events, ev_tstamp timeout, void (*cb)(int revents, void *arg), void *arg);
+#endif
+
+/* these may evaluate ev multiple times, and the other arguments at most once */
+/* either use ev_watcher_init + ev_TYPE_set, or the ev_TYPE_init macro, below, to first initialise a watcher */
+#define ev_watcher_init(ev,cb_) do { \
+ ((struct ev_watcher *)(void *)(ev))->active = \
+ ((struct ev_watcher *)(void *)(ev))->pending = \
+ ((struct ev_watcher *)(void *)(ev))->priority = 0; \
+ (ev)->cb = (cb_); \
+} while (0)
+
+#define ev_io_set(ev,fd_,events_) do { (ev)->fd = (fd_); (ev)->events = (events_); } while (0)
+#define ev_timer_set(ev,after_,repeat_) do { (ev)->at = (after_); (ev)->repeat = (repeat_); } while (0)
+#define ev_periodic_set(ev,at_,interval_) do { (ev)->at = (at_); (ev)->interval = (interval_); } while (0)
+#define ev_signal_set(ev,signum_) do { (ev)->signum = (signum_); } while (0)
+#define ev_idle_set(ev) /* nop, yes, this is a serious in-joke */
+#define ev_prepare_set(ev) /* nop, yes, this is a serious in-joke */
+#define ev_check_set(ev) /* nop, yes, this is a serious in-joke */
+#define ev_child_set(ev,pid_) do { (ev)->pid = (pid_); } while (0)
+
+#define ev_io_init(ev,cb,fd,events) do { ev_watcher_init ((ev), (cb)); ev_io_set ((ev),(fd),(events)); } while (0)
+#define ev_timer_init(ev,cb,after,repeat) do { ev_watcher_init ((ev), (cb)); ev_timer_set ((ev),(after),(repeat)); } while (0)
+#define ev_periodic_init(ev,cb,at,interval) do { ev_watcher_init ((ev), (cb)); ev_periodic_set ((ev),(at),(interval)); } while (0)
+#define ev_signal_init(ev,cb,signum) do { ev_watcher_init ((ev), (cb)); ev_signal_set ((ev), (signum)); } while (0)
+#define ev_idle_init(ev,cb) do { ev_watcher_init ((ev), (cb)); ev_idle_set ((ev)); } while (0)
+#define ev_prepare_init(ev,cb) do { ev_watcher_init ((ev), (cb)); ev_prepare_set ((ev)); } while (0)
+#define ev_check_init(ev,cb) do { ev_watcher_init ((ev), (cb)); ev_check_set ((ev)); } while (0)
+#define ev_child_init(ev,cb,pid) do { ev_watcher_init ((ev), (cb)); ev_child_set ((ev),(pid)); } while (0)
+
+#define ev_is_pending(ev) (0 + ((struct ev_watcher *)(void *)(ev))->pending) /* ro, true when watcher is waiting for callback invocation */
+#define ev_is_active(ev) (0 + ((struct ev_watcher *)(void *)(ev))->active) /* ro, true when the watcher has been started */
+
+#define ev_priority(ev) ((struct ev_watcher *)(void *)(ev))->priority /* rw */
+#define ev_cb(ev) (ev)->cb /* rw */
+#define ev_set_priority(ev,pri) ev_priority (ev) = (pri)
+#define ev_set_cb(ev,cb_) ev_cb (ev) = (cb_)