--- libev/ev.h	2007/10/31 07:24:17	1.5
+++ libev/ev.h	2007/10/31 09:23:18	1.6
@@ -13,25 +13,47 @@
 #define EV_IDLE    0x10
 #define EV_CHECK   0x20
 
+/* can be used to add custom fields to all watchers */
+#ifndef EV_COMMON
+# define EV_COMMON void *data
+#endif
+
+/*
+ * struct member types:
+ * private: you can look at them, but not change them, and they might not mean anything to you.
+ * ro: can be read anytime, but only changed when the watcher isn't active
+ * rw: can be read and modified anytime, even when the watcher is active
+ */
+
 /* shared by all watchers */
 #define EV_WATCHER(type)			\
   int active; /* private */			\
   int pending; /* private */			\
-  void *data; /* rw */				\
-  void (*cb)(struct type *, int revents) /* rw */ /* gets invoked with an eventmask */
+  EV_COMMON; /* rw */				\
+  void (*cb)(struct type *, int revents); /* rw */ /* gets invoked with an eventmask */
 
 #define EV_WATCHER_LIST(type)			\
   EV_WATCHER (type);				\
   struct type *next /* private */
 
-/* invoked at a specific time or after a specific time, repeatable */
+#define EV_WATCHER_TIME(type)			\
+  EV_WATCHER (type);				\
+  ev_tstamp at     /* private */
+
+/* invoked after a specific time, repeatable (based on monotonic clock) */
 struct ev_timer
 {
-  EV_WATCHER_LIST (ev_timer);
+  EV_WATCHER_TIME (ev_timer);
 
-  ev_tstamp at;     /* private */
   ev_tstamp repeat; /* rw */
-  unsigned char is_abs; /* ro */
+};
+
+/* invoked at some specific time, possibly repeating at regular intervals (based on UTC) */
+struct ev_periodic
+{
+  EV_WATCHER_TIME (ev_periodic);
+
+  ev_tstamp interval; /* rw */
 };
 
 /* invoked when fd is either EV_READable or EV_WRITEable */
@@ -83,31 +105,44 @@
 extern int ev_loop_done; /* set to 1 to break out of event loop */
 
 /* these may evaluate ev multiple times, and the other arguments at most once */
-#define evw_init(ev,cb_,data_)             do { (ev)->active = 0; (ev)->cb = (cb_); (ev)->data = (void *)data_; } while (0)
+/* either use evw_init + evXXX_set, or the evXXX_init macro, below, to first initialise a watcher */
+#define evw_init(ev,cb_)                   do { (ev)->active = 0; (ev)->cb = (cb_); } while (0)
 
 #define evio_set(ev,fd_,events_)           do { (ev)->fd = (fd_); (ev)->events = (events_); } while (0)
-#define evtimer_set_rel(ev,after_,repeat_) do { (ev)->at = (after_); (ev)->repeat = (repeat_); (ev)->is_abs = 0; } while (0)
-#define evtimer_set_abs(ev,at_,repeat_)    do { (ev)->at = (at_); (ev)->repeat = (repeat_); (ev)->is_abs = 1; } while (0)
+#define evtimer_set(ev,after_,repeat_)     do { (ev)->at = (after_); (ev)->repeat = (repeat_); } while (0)
+#define evperiodic_set(ev,at_,interval_)   do { (ev)->at = (at_); (ev)->interval = (interval_); } while (0)
 #define evsignal_set(ev,signum_)           do { (ev)->signum = (signum_); } while (0)
+#define evcheck_set(ev)                    /* nop, yes this is a serious in-joke */
+#define evidle_set(ev)                     /* nop, yes this is a serious in-joke */
+
+#define evio_init(ev,cb,fd,events)         do { evw_init ((ev), (cb)); evio_set ((ev),(fd),(events)); } while (0)
+#define evtimer_init(ev,cb,after,repeat)   do { evw_init ((ev), (cb)); evtimer_set ((ev),(after),(repeat)); } while (0)
+#define evperiodic_init(ev,cb,at,interval) do { evw_init ((ev), (cb)); evperiodic_set ((ev),(at),(interval)); } while (0)
+#define evsignal_init(ev,cb,signum)        do { evw_init ((ev), (cb)); evsignal_set ((ev), (signum)); } while (0)
+#define evcheck_init(ev,cb)                do { evw_init ((ev), (cb)); evcheck_set ((ev)); } while (0)
+#define evidle_init(ev,cb)                 do { evw_init ((ev), (cb)); evidle_set ((ev)); } while (0)
 
 #define ev_is_active(ev) (0 + (ev)->active) /* true when the watcher has been started */
 
 /* stopping (enabling, adding) a watcher does nothing if it is already running */
 /* stopping (disabling, deleting) a watcher does nothing unless its already running */
-void evio_start     (struct ev_io *w);
-void evio_stop      (struct ev_io *w);
+void evio_start       (struct ev_io *w);
+void evio_stop        (struct ev_io *w);
+
+void evtimer_start    (struct ev_timer *w);
+void evtimer_stop     (struct ev_timer *w);
 
-void evtimer_start  (struct ev_timer *w);
-void evtimer_stop   (struct ev_timer *w);
+void evperiodic_start (struct ev_periodic *w);
+void evperiodic_stop  (struct ev_periodic *w);
 
-void evsignal_start (struct ev_signal *w);
-void evsignal_stop  (struct ev_signal *w);
+void evsignal_start   (struct ev_signal *w);
+void evsignal_stop    (struct ev_signal *w);
 
-void evidle_start   (struct ev_idle *w);
-void evidle_stop    (struct ev_idle *w);
+void evidle_start     (struct ev_idle *w);
+void evidle_stop      (struct ev_idle *w);
 
-void evcheck_start  (struct ev_check *w);
-void evcheck_stop   (struct ev_check *w);
+void evcheck_start    (struct ev_check *w);
+void evcheck_stop     (struct ev_check *w);
 
 #endif