`ev_timer` - relative and optionally recurring timeouts

Timer watchers are simple relative timers that generate an event after a given time, and optionally repeating in regular intervals after that.

The timers are based on real time, that is, if you register an event that @@ -499,7 +499,7 @@ value), or reset the running timer to the repeat value.

example: Imagine you have a tcp connection and you want a so-called idle timeout, that is, you want to be called when there have been, say, 60 seconds of inactivity on the socket. The easiest way to do this is to -configure an ev_timer with after=repeat=60 and calling ev_timer_again each +configure an ev_timer with after=repeat=60 and calling ev_timer_again each time you successfully read or write some data. If you go into an idle state where you do not expect data to travel on the socket, you can stop the timer, and again will automatically restart it if need be.

@@ -507,16 +507,16 @@ the timer, and again will automatically restart it if need be.

ev_periodic - to cron or not to cron it

`ev_periodic` - to cron or not to cron it

Periodic watchers are also timers of a kind, but they are very versatile (and unfortunately a bit complex).

Unlike ev_timer's, they are not based on real time (or relative time) +

Unlike ev_timer's, they are not based on real time (or relative time) but on wallclock time (absolute time). You can tell a periodic watcher to trigger "at" some specific point in time. For example, if you tell a periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now () + 10.>) and then reset your system clock to the last year, then it will -take a year to trigger the event (unlike an ev_timer, which would trigger +take a year to trigger the event (unlike an ev_timer, which would trigger roughly 10 seconds later and of course not if you reset your system time again).

They can also be used to implement vastly more complex timers, such as @@ -555,7 +555,7 @@ but only that the the callback will be called when the system time shows a full hour (UTC), or more correct, when the system time is evenly divisible by 3600.

Another way to think about it (for the mathematically inclined) is that -ev_periodic will try to run the callback in this mode at the next possible +ev_periodic will try to run the callback in this mode at the next possible time where time = at (mod interval), regardless of any time jumps.

* manual reschedule mode (reschedule_cb = callback)

@@ -597,8 +597,8 @@ program when the crontabs have changed).

ev_signal - signal me when a signal gets signalled

`ev_signal` - signal me when a signal gets signalled

Signal watchers will trigger an event when the process receives a specific signal one or more times. Even though signals are very asynchronous, libev will try it's best to deliver signals synchronously, i.e. as part of the @@ -619,8 +619,8 @@ of the SIGxxx constants).

ev_child - wait for pid status changes

`ev_child` - wait for pid status changes

Child watchers trigger when your process receives a SIGCHLD in response to some child status changes (most typically when a child of yours dies).

@@ -636,8 +636,8 @@ contains the pid of the process causing the status change.

ev_idle - when you've got nothing better to do

`ev_idle` - when you've got nothing better to do

Idle watchers trigger events when there are no other I/O or timer (or periodic) events pending. That is, as long as your process is busy handling sockets or timeouts it will not be called. But when your process @@ -668,8 +668,8 @@ watchers afterwards.

could be used, for example, to track variable changes, implement your own watchers, integrate net-snmp or a coroutine library and lots more.

This is done by examining in each prepare call which file descriptors need -to be watched by the other library, registering ev_io watchers for them -and starting an ev_timer watcher for any timeouts (many libraries provide +to be watched by the other library, registering ev_io watchers for them +and starting an ev_timer watcher for any timeouts (many libraries provide just this functionality). Then, in the check watcher you check for any events that occured (by making your callbacks set soem flags for example) and call back into the library.

@@ -700,14 +700,14 @@ watchers. This is useful if you want to wait for a single event on an fd or timeout without havign to allocate/configure/start/stop/free one or more watchers yourself.

If fd is less than 0, then no I/O watcher will be started and events is -ignored. Otherwise, an ev_io watcher for the given fd and events set +ignored. Otherwise, an ev_io watcher for the given fd and events set will be craeted and started.

If timeout is less than 0, then no timeout watcher will be -started. Otherwise an ev_timer watcher with after = timeout (and repeat +started. Otherwise an ev_timer watcher with after = timeout (and repeat = 0) will be started.

The callback has the type void (*cb)(int revents, void *arg) and -gets passed an events set (normally a combination of EV_ERROR, EV_READ, -EV_WRITE or EV_TIMEOUT) and the arg value passed to ev_once:

+gets passed an events set (normally a combination of EV_ERROR, EV_READ, +EV_WRITE or EV_TIMEOUT) and the arg value passed to ev_once:

  static void stdin_ready (int revents, void *arg)
   {
     if (revents & EV_TIMEOUT)
diff --git a/ev.pod b/ev.pod
index 5d79c5d..62a8299 100644
--- a/ev.pod
+++ b/ev.pod
@@ -406,7 +406,7 @@ have been omitted....
 This section describes each watcher in detail, but will not repeat
 information given in the last section.
 
-=head2 C - is my file descriptor readable or writable
+=head2 C - is this file descriptor readable or writable
 
 I/O watchers check whether a file descriptor is readable or writable
 in each iteration of the event loop (This behaviour is called
@@ -546,7 +546,7 @@ time:
 
 This doesn't mean there will always be 3600 seconds in between triggers,
 but only that the the callback will be called when the system time shows a
-full hour (UTC), or more correct, when the system time is evenly divisible
+full hour (UTC), or more correctly, when the system time is evenly divisible
 by 3600.
 
 Another way to think about it (for the mathematically inclined) is that
@@ -561,8 +561,11 @@ reschedule callback will be called with the watcher as first, and the
 current time as second argument.
 
 NOTE: I. If you need
-to stop it, return 1e30 (or so, fudge fudge) and stop it afterwards.
+periodic watcher, ever, or make any event loop modifications>. If you need
+to stop it, return C (or so, fudge fudge) and stop it afterwards.
+
+Also, I< value >>. Not even C itself will be ok.
 
 Its prototype is c, e.g.:

struct ev_io - is my file descriptor readable or writable

`ev_io` - is my file descriptor readable or writable

struct ev_timer - relative and optionally recurring timeouts