X-Git-Url: https://git.llucax.com/software/libev.git/blobdiff_plain/8314a2bcfca6fbd1d9fcac78400d7c381b2c01ff..c585a019b5590e9c5b01a77fc81088d551c99da9:/ev.html diff --git a/ev.html b/ev.html index abaebaa..6fc304d 100644 --- a/ev.html +++ b/ev.html @@ -6,7 +6,7 @@ - +
@@ -26,12 +26,12 @@ev_io
- is this file descriptor readable or writableev_timer
- relative and optionally recurring timeoutsev_periodic
- to cron or not to cron itev_signal
- signal me when a signal gets signalledev_child
- wait for pid status changesev_idle
- when you've got nothing better to doIt supports the following flags:
EVFLAG_AUTO
The default flags value. Use this if you have no clue (it's the right thing, believe me).
EVFLAG_NOENV
If this flag bit is ored into the flag value (or the program runs setuid or setgid) then libev will not look at the environment variable @@ -177,12 +177,12 @@ override the flags completely if it is found in the environment. This is useful to try out specific backends to test their performance, or to work around bugs.
EVMETHOD_SELECT
(portable select backend)EVMETHOD_POLL
(poll backend, available everywhere except on windows)EVMETHOD_EPOLL
(linux only)EVMETHOD_KQUEUE
(some bsds only)EVMETHOD_DEVPOLL
(solaris 8 only)EVMETHOD_PORT
(solaris 10 only)If one or more of these are ored into the flags value, then only these backends will be tried (in the reverse order as given here). If one are @@ -290,7 +290,7 @@ libraries. Just remember to unref after start and ref before stop.
A watcher is a structure that you create and register to record your interest in some event. For instance, if you want to wait for STDIN to -become readable, you would create an ev_io watcher for that:
+become readable, you would create anev_io
watcher for that:
static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) { ev_io_stop (w); @@ -335,44 +335,44 @@ third argument. (you can receive multiple events at the same time). The possible bit masks are:
EV_READ
EV_WRITE
The file descriptor in the ev_io watcher has become readable and/or +
The file descriptor in the ev_io
watcher has become readable and/or
writable.
EV_TIMEOUT
The ev_timer watcher has timed out.
+The ev_timer
watcher has timed out.
EV_PERIODIC
The ev_periodic watcher has timed out.
+The ev_periodic
watcher has timed out.
EV_SIGNAL
The signal specified in the ev_signal watcher has been received by a thread.
+The signal specified in the ev_signal
watcher has been received by a thread.
EV_CHILD
The pid specified in the ev_child watcher has received a status change.
+The pid specified in the ev_child
watcher has received a status change.
EV_IDLE
The ev_idle watcher has determined that you have nothing better to do.
+The ev_idle
watcher has determined that you have nothing better to do.
EV_PREPARE
EV_CHECK
All ev_prepare watchers are invoked just before ev_loop
starts
-to gather new events, and all ev_check watchers are invoked just after
+
All ev_prepare
watchers are invoked just before ev_loop
starts
+to gather new events, and all ev_check
watchers are invoked just after
ev_loop
has gathered them, but before it invokes any callbacks for any
received events. Callbacks of both watcher types can start and stop as
many watchers as they want, and all of them will be taken into account
-(for example, a ev_prepare watcher might start an idle watcher to keep
+(for example, a ev_prepare
watcher might start an idle watcher to keep
ev_loop
from blocking).
EV_ERROR
An unspecified error has occured, the watcher has been stopped. This might happen because the watcher could not be properly started because libev @@ -428,8 +428,8 @@ have been omitted....
information given in the last section.ev_io
- is this file descriptor readable or writableI/O watchers check whether a file descriptor is readable or writable in each iteration of the event loop (This behaviour is called level-triggering because you keep receiving events as long as the @@ -450,15 +450,15 @@ EVMETHOD_POLL).
Configures an ev_io watcher. The fd is the file descriptor to rceeive +
Configures an ev_io
watcher. The fd is the file descriptor to rceeive
events for and events is either EV_READ
, EV_WRITE
or EV_READ |
EV_WRITE
to receive the given events.
ev_timer
- relative and optionally recurring timeoutsTimer 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 anev_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 itPeriodic 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.
ev_signal
- signal me when a signal gets signalledSignal 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 changesChild watchers trigger when your process receives a SIGCHLD in response to some child status changes (most typically when a child of yours dies).
ev_idle
- when you've got nothing better to doIdle 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.
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
:
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)