[ViewVC] Diff of: cvs/EV/EV.pm

Comparing EV/EV.pm (file contents):
Revision 1.29 by root, Tue Nov 6 17:20:42 2007 UTC vs.
Revision 1.64 by root, Sat Dec 8 02:55:13 2007 UTC

…		…
10		10
11	my $w = EV::timer 2, 0, sub {	11	my $w = EV::timer 2, 0, sub {
12	warn "is called after 2s";	12	warn "is called after 2s";
13	};	13	};
14		14
15	my $w = EV::timer 2, 1, sub {	15	my $w = EV::timer 2, 2, sub {
16	warn "is called roughly every 2s (repeat = 1)";	16	warn "is called roughly every 2s (repeat = 2)";
17	};	17	};
18		18
19	undef $w; # destroy event watcher again	19	undef $w; # destroy event watcher again
20		20
21	my $w = EV::periodic 0, 60, sub {	21	my $w = EV::periodic 0, 60, 0, sub {
22	warn "is called every minute, on the minute, exactly";	22	warn "is called every minute, on the minute, exactly";
23	};	23	};
24		24
25	# IO	25	# IO
26		26
27	my $w = EV::io *STDIN, EV::READ, sub {	27	my $w = EV::io *STDIN, EV::READ, sub {
28	my ($w, $revents) = @_; # all callbacks get the watcher object and event mask	28	my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
29	warn "stdin is readable, you entered: ", <STDIN>;	29	warn "stdin is readable, you entered: ", <STDIN>;
30	};	30	};
31		31
32	# SIGNALS	32	# SIGNALS
33		33
34	my $w = EV::signal 'QUIT', sub {	34	my $w = EV::signal 'QUIT', sub {
35	warn "sigquit received\n";	35	warn "sigquit received\n";
36	};	36	};
37		37
38	my $w = EV::signal 3, sub {
39	warn "sigquit received (this is GNU/Linux, right?)\n";
40	};
41
42	# CHILD/PID STATUS CHANGES	38	# CHILD/PID STATUS CHANGES
43		39
44	my $w = EV::child 666, sub {	40	my $w = EV::child 666, sub {
45	my ($w, $revents) = @_;	41	my ($w, $revents) = @_;
46	# my $pid = $w->rpid;
47	my $status = $w->rstatus;	42	my $status = $w->rstatus;
48	};	43	};
		44
		45	# STAT CHANGES
		46	my $w = EV::stat "/etc/passwd", 10, sub {
		47	my ($w, $revents) = @_;
		48	warn $w->path, " has changed somehow.\n";
		49	};
49		50
50	# MAINLOOP	51	# MAINLOOP
51	EV::loop; # loop until EV::loop_done is called	52	EV::loop; # loop until EV::unloop is called or all watchers stop
52	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled	53	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
53	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block	54	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
54		55
55	=head1 DESCRIPTION	56	=head1 DESCRIPTION
56		57
57	This module provides an interface to libev	58	This module provides an interface to libev
58	(L<http://software.schmorp.de/pkg/libev.html>).	59	(L<http://software.schmorp.de/pkg/libev.html>). While the documentation
		60	below is comprehensive, one might also consult the documentation of libev
		61	itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on
		62	watcher semantics or some discussion on the available backends, or how to
		63	force a specific backend with C<LIBEV_FLAGS>, or just about in any case
		64	because it has much more detailed information.
59		65
60	=cut	66	=cut
61		67
62	package EV;	68	package EV;
63		69
64	use strict;	70	use strict;
65		71
66	BEGIN {	72	BEGIN {
67	our $VERSION = '0.51';	73	our $VERSION = '1.8';
68	use XSLoader;	74	use XSLoader;
69	XSLoader::load "EV", $VERSION;	75	XSLoader::load "EV", $VERSION;
70	}	76	}
71		77
72	@EV::Io::ISA =	78	@EV::IO::ISA =
73	@EV::Timer::ISA =	79	@EV::Timer::ISA =
74	@EV::Periodic::ISA =	80	@EV::Periodic::ISA =
75	@EV::Signal::ISA =	81	@EV::Signal::ISA =
		82	@EV::Child::ISA =
		83	@EV::Stat::ISA =
76	@EV::Idle::ISA =	84	@EV::Idle::ISA =
77	@EV::Prepare::ISA =	85	@EV::Prepare::ISA =
78	@EV::Check::ISA =	86	@EV::Check::ISA =
79	@EV::Child::ISA = "EV::Watcher";	87	@EV::Embed::ISA =
		88	@EV::Fork::ISA =
		89	"EV::Watcher";
80		90
81	=head1 BASIC INTERFACE	91	=head1 BASIC INTERFACE
82		92
83	=over 4	93	=over 4
84		94
…		…
98		108
99	Returns the time the last event loop iteration has been started. This	109	Returns the time the last event loop iteration has been started. This
100	is the time that (relative) timers are based on, and refering to it is	110	is the time that (relative) timers are based on, and refering to it is
101	usually faster then calling EV::time.	111	usually faster then calling EV::time.
102		112
103	=item $method = EV::ev_method	113	=item $method = EV::method
104		114
105	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	115	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
106	or EV::METHOD_EPOLL).	116	or EV::METHOD_EPOLL).
107		117
108	=item EV::loop [$flags]	118	=item EV::loop [$flags]
109		119
110	Begin checking for events and calling callbacks. It returns when a	120	Begin checking for events and calling callbacks. It returns when a
111	callback calls EV::loop_done.	121	callback calls EV::unloop.
112		122
113	The $flags argument can be one of the following:	123	The $flags argument can be one of the following:
114		124
115	0 as above	125	0 as above
116	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	126	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
117	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	127	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
118		128
119	=item EV::loop_done [$how]	129	=item EV::unloop [$how]
120		130
121	When called with no arguments or an argument of 1, makes the innermost	131	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
122	call to EV::loop return.	132	innermost call to EV::loop return.
123		133
124	When called with an agrument of 2, all calls to EV::loop will return as	134	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
125	fast as possible.	135	fast as possible.
126		136
127	=back	137	=item $count = EV::loop_count
128		138
		139	Return the number of times the event loop has polled for new
		140	events. Sometiems useful as a generation counter.
		141
		142	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		143
		144	This function rolls together an I/O and a timer watcher for a single
		145	one-shot event without the need for managing a watcher object.
		146
		147	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		148	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		149	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		150	you do not want to wait for some I/O event, specify C<undef> for
		151	C<$fh_or_undef> and C<0> for C<$events>).
		152
		153	If timeout is C<undef> or negative, then there will be no
		154	timeout. Otherwise a EV::timer with this value will be started.
		155
		156	When an error occurs or either the timeout or I/O watcher triggers, then
		157	the callback will be called with the received event set (in general
		158	you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>,
		159	C<EV::WRITE> and C<EV::TIMEOUT>).
		160
		161	EV::once doesn't return anything: the watchers stay active till either
		162	of them triggers, then they will be stopped and freed, and the callback
		163	invoked.
		164
		165	=back
		166
129	=head2 WATCHER	167	=head2 WATCHER OBJECTS
130		168
131	A watcher is an object that gets created to record your interest in some	169	A watcher is an object that gets created to record your interest in some
132	event. For instance, if you want to wait for STDIN to become readable, you	170	event. For instance, if you want to wait for STDIN to become readable, you
133	would create an EV::io watcher for that:	171	would create an EV::io watcher for that:
134		172
…		…
143	events.	181	events.
144		182
145	Each watcher type has its associated bit in revents, so you can use the	183	Each watcher type has its associated bit in revents, so you can use the
146	same callback for multiple watchers. The event mask is named after the	184	same callback for multiple watchers. The event mask is named after the
147	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,	185	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
148	EV::periodic sets EV::PERIODIC and so on, with the exception of IO events	186	EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events
149	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which	187	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
150	uses EV::TIMEOUT).	188	uses EV::TIMEOUT).
151		189
152	In the rare case where one wants to create a watcher but not start it at	190	In the rare case where one wants to create a watcher but not start it at
153	the same time, each constructor has a variant with a trailing C<_ns> in	191	the same time, each constructor has a variant with a trailing C<_ns> in
…		…
159		197
160	Also, all methods changing some aspect of a watcher (->set, ->priority,	198	Also, all methods changing some aspect of a watcher (->set, ->priority,
161	->fh and so on) automatically stop and start it again if it is active,	199	->fh and so on) automatically stop and start it again if it is active,
162	which means pending events get lost.	200	which means pending events get lost.
163		201
164	=head2 WATCHER TYPES	202	=head2 COMMON WATCHER METHODS
165		203
166	Now lets move to the existing watcher types and asociated methods.	204	This section lists methods common to all watchers.
167
168	The following methods are available for all watchers. Then followes a
169	description of each watcher constructor (EV::io, EV::timer, EV::periodic,
170	EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by
171	any type-specific methods (if any).
172		205
173	=over 4	206	=over 4
174		207
175	=item $w->start	208	=item $w->start
176		209
…		…
180		213
181	=item $w->stop	214	=item $w->stop
182		215
183	Stop a watcher if it is active. Also clear any pending events (events that	216	Stop a watcher if it is active. Also clear any pending events (events that
184	have been received but that didn't yet result in a callback invocation),	217	have been received but that didn't yet result in a callback invocation),
185	regardless of wether the watcher was active or not.	218	regardless of whether the watcher was active or not.
186		219
187	=item $bool = $w->is_active	220	=item $bool = $w->is_active
188		221
189	Returns true if the watcher is active, false otherwise.	222	Returns true if the watcher is active, false otherwise.
		223
		224	=item $current_data = $w->data
		225
		226	=item $old_data = $w->data ($new_data)
		227
		228	Queries a freely usable data scalar on the watcher and optionally changes
		229	it. This is a way to associate custom data with a watcher:
		230
		231	my $w = EV::timer 60, 0, sub {
		232	warn $_[0]->data;
		233	};
		234	$w->data ("print me!");
190		235
191	=item $current_cb = $w->cb	236	=item $current_cb = $w->cb
192		237
193	=item $old_cb = $w->cb ($new_cb)	238	=item $old_cb = $w->cb ($new_cb)
194		239
…		…
203	watchers with higher priority will be invoked first. The valid range of	248	watchers with higher priority will be invoked first. The valid range of
204	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default	249	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
205	-2). If the priority is outside this range it will automatically be	250	-2). If the priority is outside this range it will automatically be
206	normalised to the nearest valid priority.	251	normalised to the nearest valid priority.
207		252
208	The default priority of any newly-created weatcher is 0.	253	The default priority of any newly-created watcher is 0.
		254
		255	Note that the priority semantics have not yet been fleshed out and are
		256	subject to almost certain change.
209		257
210	=item $w->trigger ($revents)	258	=item $w->trigger ($revents)
211		259
212	Call the callback now with the given event mask.	260	Call the callback now with the given event mask.
213		261
		262	=item $previous_state = $w->keepalive ($bool)
		263
		264	Normally, C<EV::loop> will return when there are no active watchers
		265	(which is a "deadlock" because no progress can be made anymore). This is
		266	convinient because it allows you to start your watchers (and your jobs),
		267	call C<EV::loop> once and when it returns you know that all your jobs are
		268	finished (or they forgot to register some watchers for their task :).
		269
		270	Sometimes, however, this gets in your way, for example when you the module
		271	that calls C<EV::loop> (usually the main program) is not the same module
		272	as a long-living watcher (for example a DNS client module written by
		273	somebody else even). Then you might want any outstanding requests to be
		274	handled, but you would not want to keep C<EV::loop> from returning just
		275	because you happen to have this long-running UDP port watcher.
		276
		277	In this case you can clear the keepalive status, which means that even
		278	though your watcher is active, it won't keep C<EV::loop> from returning.
		279
		280	The initial value for keepalive is true (enabled), and you cna change it
		281	any time.
		282
		283	Example: Register an I/O watcher for some UDP socket but do not keep the
		284	event loop from running just because of that watcher.
		285
		286	my $udp_socket = ...
		287	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		288	$udp_watcher->keepalive (0);
		289
		290	=back
		291
		292
		293	=head2 WATCHER TYPES
		294
		295	Each of the following subsections describes a single watcher type.
		296
		297	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		298
		299	=over 4
214		300
215	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	301	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
216		302
217	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	303	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
218		304
219	As long as the returned watcher object is alive, call the C<$callback>	305	As long as the returned watcher object is alive, call the C<$callback>
220	when the events specified in C<$eventmask>.	306	when at least one of events specified in C<$eventmask> occurs.
221		307
222	The $eventmask can be one or more of these constants ORed together:	308	The $eventmask can be one or more of these constants ORed together:
223		309
224	EV::READ wait until read() wouldn't block anymore	310	EV::READ wait until read() wouldn't block anymore
225	EV::WRITE wait until write() wouldn't block anymore	311	EV::WRITE wait until write() wouldn't block anymore
…		…
241		327
242	=item $old_eventmask = $w->events ($new_eventmask)	328	=item $old_eventmask = $w->events ($new_eventmask)
243		329
244	Returns the previously set event mask and optionally set a new one.	330	Returns the previously set event mask and optionally set a new one.
245		331
		332	=back
		333
		334
		335	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		336
		337	=over 4
246		338
247	=item $w = EV::timer $after, $repeat, $callback	339	=item $w = EV::timer $after, $repeat, $callback
248		340
249	=item $w = EV::timer_ns $after, $repeat, $callback	341	=item $w = EV::timer_ns $after, $repeat, $callback
250		342
251	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	343	Calls the callback after C<$after> seconds (which may be fractional). If
252	the timer will be restarted (with the $repeat value as $after) after the	344	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
253	callback returns.	345	value as $after) after the callback returns.
254		346
255	This means that the callback would be called roughly after C<$after>	347	This means that the callback would be called roughly after C<$after>
256	seconds, and then every C<$repeat> seconds. "Roughly" because the time of	348	seconds, and then every C<$repeat> seconds. The timer does his best not
257	callback processing is not taken into account, so the timer will slowly	349	to drift, but it will not invoke the timer more often then once per event
258	drift. If that isn't acceptable, look at EV::periodic.	350	loop iteration, and might drift in other cases. If that isn't acceptable,
		351	look at EV::periodic, which can provide long-term stable timers.
259		352
260	The timer is based on a monotonic clock, that is if somebody is sitting	353	The timer is based on a monotonic clock, that is, if somebody is sitting
261	in front of the machine while the timer is running and changes the system	354	in front of the machine while the timer is running and changes the system
262	clock, the timer will nevertheless run (roughly) the same time.	355	clock, the timer will nevertheless run (roughly) the same time.
263		356
264	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	357	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
265		358
266	=item $w->set ($after, $repeat)	359	=item $w->set ($after, $repeat)
267		360
268	Reconfigures the watcher, see the constructor above for details. Can be at	361	Reconfigures the watcher, see the constructor above for details. Can be called at
269	any time.	362	any time.
270		363
271	=item $w->again	364	=item $w->again
272		365
273	Similar to the C<start> method, but has special semantics for repeating timers:	366	Similar to the C<start> method, but has special semantics for repeating timers:
		367
		368	If the timer is active and non-repeating, it will be stopped.
274		369
275	If the timer is active and repeating, reset the timeout to occur	370	If the timer is active and repeating, reset the timeout to occur
276	C<$repeat> seconds after now.	371	C<$repeat> seconds after now.
277		372
278	If the timer is active and non-repeating, it will be stopped.
279
280	If the timer is in active and repeating, start it.	373	If the timer is inactive and repeating, start it using the repeat value.
281		374
282	Otherwise do nothing.	375	Otherwise do nothing.
283		376
284	This behaviour is useful when you have a timeout for some IO	377	This behaviour is useful when you have a timeout for some IO
285	operation. You create a timer object with the same value for C<$after> and	378	operation. You create a timer object with the same value for C<$after> and
286	C<$repeat>, and then, in the read/write watcher, run the C<again> method	379	C<$repeat>, and then, in the read/write watcher, run the C<again> method
287	on the timeout.	380	on the timeout.
288		381
		382	=back
289		383
		384
		385	=head3 PERIODIC WATCHERS - to cron or not to cron?
		386
		387	=over 4
		388
290	=item $w = EV::periodic $at, $interval, $callback	389	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
291		390
292	=item $w = EV::periodic_ns $at, $interval, $callback	391	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
293		392
294	Similar to EV::timer, but the time is given as an absolute point in time	393	Similar to EV::timer, but is not based on relative timeouts but on
295	(C<$at>), plus an optional C<$interval>.	394	absolute times. Apart from creating "simple" timers that trigger "at" the
		395	specified time, it can also be used for non-drifting absolute timers and
		396	more complex, cron-like, setups that are not adversely affected by time
		397	jumps (i.e. when the system clock is changed by explicit date -s or other
		398	means such as ntpd). It is also the most complex watcher type in EV.
296		399
297	If the C<$interval> is zero, then the callback will be called at the time	400	It has three distinct "modes":
298	C<$at> if that is in the future, or as soon as possible if it is in the
299	past. It will not automatically repeat.
300		401
301	If the C<$interval> is nonzero, then the watcher will always be scheduled	402	=over 4
302	to time out at the next C<$at + N * $interval> time.
303		403
304	This can be used to schedule a callback to run at very regular intervals,	404	=item * absolute timer ($interval = $reschedule_cb = 0)
305	as long as the processing time is less then the interval (otherwise	405
306	obviously events will be skipped).	406	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		407	will not adjust when a time jump occurs, that is, if it is to be run
		408	at January 1st 2011 then it will run when the system time reaches or
		409	surpasses this time.
		410
		411	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)
		412
		413	In this mode the watcher will always be scheduled to time out at the
		414	next C<$at + N * $interval> time (for some integer N) and then repeat,
		415	regardless of any time jumps.
		416
		417	This can be used to create timers that do not drift with respect to system
		418	time:
		419
		420	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		421
		422	That doesn't mean there will always be 3600 seconds in between triggers,
		423	but only that the the clalback will be called when the system time shows a
		424	full hour (UTC).
307		425
308	Another way to think about it (for the mathematically inclined) is that	426	Another way to think about it (for the mathematically inclined) is that
309	EV::periodic will try to run the callback at the next possible time where	427	EV::periodic will try to run the callback in this mode at the next
310	C<$time = $at (mod $interval)>, regardless of any time jumps.	428	possible time where C<$time = $at (mod $interval)>, regardless of any time
		429	jumps.
311		430
312	This periodic timer is based on "wallclock time", that is, if the clock	431	=item * manual reschedule mode ($reschedule_cb = coderef)
313	changes (C<ntp>, C<date -s> etc.), then the timer will nevertheless run at	432
314	the specified time. This means it will never drift (it might jitter, but	433	In this mode $interval and $at are both being ignored. Instead, each
315	it will not drift).	434	time the periodic watcher gets scheduled, the reschedule callback
		435	($reschedule_cb) will be called with the watcher as first, and the current
		436	time as second argument.
		437
		438	I<This callback MUST NOT stop or destroy this or any other periodic
		439	watcher, ever>. If you need to stop it, return 1e30 and stop it
		440	afterwards.
		441
		442	It must return the next time to trigger, based on the passed time value
		443	(that is, the lowest time value larger than to the second argument). It
		444	will usually be called just before the callback will be triggered, but
		445	might be called at other times, too.
		446
		447	This can be used to create very complex timers, such as a timer that
		448	triggers on each midnight, local time (actually 24 hours after the last
		449	midnight, to keep the example simple. If you know a way to do it correctly
		450	in about the same space (without requiring elaborate modules), drop me a
		451	note :):
		452
		453	my $daily = EV::periodic 0, 0, sub {
		454	my ($w, $now) = @_;
		455
		456	use Time::Local ();
		457	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		458	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		459	}, sub {
		460	print "it's midnight or likely shortly after, now\n";
		461	};
		462
		463	=back
316		464
317	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	465	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
318		466
319	=item $w->set ($at, $interval)	467	=item $w->set ($at, $interval, $reschedule_cb)
320		468
321	Reconfigures the watcher, see the constructor above for details. Can be at	469	Reconfigures the watcher, see the constructor above for details. Can be called at
322	any time.	470	any time.
323		471
		472	=item $w->again
		473
		474	Simply stops and starts the watcher again.
		475
		476	=back
		477
		478
		479	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		480
		481	=over 4
324		482
325	=item $w = EV::signal $signal, $callback	483	=item $w = EV::signal $signal, $callback
326		484
327	=item $w = EV::signal_ns $signal, $callback	485	=item $w = EV::signal_ns $signal, $callback
328		486
329	Call the callback when $signal is received (the signal can be specified	487	Call the callback when $signal is received (the signal can be specified by
330	by number or by name, just as with kill or %SIG).	488	number or by name, just as with C<kill> or C<%SIG>).
331		489
332	EV will grab the signal for the process (the kernel only allows one	490	EV will grab the signal for the process (the kernel only allows one
333	component to receive a signal at a time) when you start a signal watcher,	491	component to receive a signal at a time) when you start a signal watcher,
334	and removes it again when you stop it. Perl does the same when you	492	and removes it again when you stop it. Perl does the same when you
335	add/remove callbacks to %SIG, so watch out.	493	add/remove callbacks to C<%SIG>, so watch out.
336		494
337	You can have as many signal watchers per signal as you want.	495	You can have as many signal watchers per signal as you want.
338		496
339	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	497	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
340		498
341	=item $w->set ($signal)	499	=item $w->set ($signal)
342		500
343	Reconfigures the watcher, see the constructor above for details. Can be at	501	Reconfigures the watcher, see the constructor above for details. Can be
344	any time.	502	called at any time.
345		503
346	=item $current_signum = $w->signal	504	=item $current_signum = $w->signal
347		505
348	=item $old_signum = $w->signal ($new_signal)	506	=item $old_signum = $w->signal ($new_signal)
349		507
350	Returns the previously set signal (always as a number not name) and	508	Returns the previously set signal (always as a number not name) and
351	optionally set a new one.	509	optionally set a new one.
352		510
		511	=back
		512
		513
		514	=head3 CHILD WATCHERS - watch out for process status changes
		515
		516	=over 4
353		517
354	=item $w = EV::child $pid, $callback	518	=item $w = EV::child $pid, $callback
355		519
356	=item $w = EV::child_ns $pid, $callback	520	=item $w = EV::child_ns $pid, $callback
357		521
358	Call the callback when a status change for pid C<$pid> (or any pid	522	Call the callback when a status change for pid C<$pid> (or any pid if
359	if C<$pid> is 0) has been received. More precisely: when the process	523	C<$pid> is 0) has been received. More precisely: when the process receives
360	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all	524	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
361	changed/zombie children and call the callback.	525	changed/zombie children and call the callback.
362		526
363	You can access both status and pid by using the C<rstatus> and C<rpid>	527	It is valid (and fully supported) to install a child watcher after a child
364	methods on the watcher object.	528	has exited but before the event loop has started its next iteration (for
		529	example, first you C<fork>, then the new child process might exit, and
		530	only then do you install a child watcher in the parent for the new pid).
365		531
		532	You can access both exit (or tracing) status and pid by using the
		533	C<rstatus> and C<rpid> methods on the watcher object.
		534
366	You can have as many pid watchers per pid as you want.	535	You can have as many pid watchers per pid as you want, they will all be
		536	called.
367		537
368	The C<child_ns> variant doesn't start (activate) the newly created watcher.	538	The C<child_ns> variant doesn't start (activate) the newly created watcher.
369		539
370	=item $w->set ($pid)	540	=item $w->set ($pid)
371		541
372	Reconfigures the watcher, see the constructor above for details. Can be at	542	Reconfigures the watcher, see the constructor above for details. Can be called at
373	any time.	543	any time.
374		544
375	=item $current_pid = $w->pid	545	=item $current_pid = $w->pid
376		546
377	=item $old_pid = $w->pid ($new_pid)	547	=item $old_pid = $w->pid ($new_pid)
…		…
386	=item $pid = $w->rpid	556	=item $pid = $w->rpid
387		557
388	Return the pid of the awaited child (useful when you have installed a	558	Return the pid of the awaited child (useful when you have installed a
389	watcher for all pids).	559	watcher for all pids).
390		560
		561	=back
		562
		563
		564	=head3 STAT WATCHERS - did the file attributes just change?
		565
		566	=over 4
		567
		568	=item $w = EV::stat $path, $interval, $callback
		569
		570	=item $w = EV::stat_ns $path, $interval, $callback
		571
		572	Call the callback when a file status change has been detected on
		573	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		574	to "path does not exist" is a status change like any other.
		575
		576	The C<$interval> is a recommended polling interval for systems where
		577	OS-supported change notifications don't exist or are not supported. If
		578	you use C<0> then an unspecified default is used (which is highly
		579	recommended!), which is to be expected to be around five seconds usually.
		580
		581	This watcher type is not meant for massive numbers of stat watchers,
		582	as even with OS-supported change notifications, this can be
		583	resource-intensive.
		584
		585	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		586
		587	=item ... = $w->stat
		588
		589	This call is very similar to the perl C<stat> built-in: It stats (using
		590	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		591	well as EV's idea of the current stat values) to the values found.
		592
		593	In scalar context, a boolean is return indicating success or failure of
		594	the stat. In list context, the same 13-value list as with stat is returned
		595	(except that the blksize and blocks fields are not reliable).
		596
		597	In the case of an error, errno is set to C<ENOENT> (regardless of the
		598	actual error value) and the C<nlink> value is forced to zero (if the stat
		599	was successful then nlink is guaranteed to be non-zero).
		600
		601	See also the next two entries for more info.
		602
		603	=item ... = $w->attr
		604
		605	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		606	the values most recently detected by EV. See the next entry for more info.
		607
		608	=item ... = $w->prev
		609
		610	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		611	the previous set of values, before the change.
		612
		613	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		614	to the values found I<before> a change was detected, while C<< $w->attr >>
		615	returns the values found leading to the change detection. The difference (if any)
		616	between C<prev> and C<attr> is what triggered the callback.
		617
		618	If you did something to the filesystem object and do not want to trigger
		619	yet another change, you can call C<stat> to update EV's idea of what the
		620	current attributes are.
		621
		622	=item $w->set ($path, $interval)
		623
		624	Reconfigures the watcher, see the constructor above for details. Can be
		625	called at any time.
		626
		627	=item $current_path = $w->path
		628
		629	=item $old_path = $w->path ($new_path)
		630
		631	Returns the previously set path and optionally set a new one.
		632
		633	=item $current_interval = $w->interval
		634
		635	=item $old_interval = $w->interval ($new_interval)
		636
		637	Returns the previously set interval and optionally set a new one. Can be
		638	used to query the actual interval used.
		639
		640	=back
		641
		642
		643	=head3 IDLE WATCHERS - when you've got nothing better to do...
		644
		645	=over 4
391		646
392	=item $w = EV::idle $callback	647	=item $w = EV::idle $callback
393		648
394	=item $w = EV::idle_ns $callback	649	=item $w = EV::idle_ns $callback
395		650
396	Call the callback when there are no pending io, timer/periodic, signal or	651	Call the callback when there are no other pending watchers of the same or
397	child events, i.e. when the process is idle.	652	higher priority (excluding check, prepare and other idle watchers of the
		653	same or lower priority, of course). They are called idle watchers because
		654	when the watcher is the highest priority pending event in the process, the
		655	process is considered to be idle at that priority.
		656
		657	If you want a watcher that is only ever called when I<no> other events are
		658	outstanding you have to set the priority to C<EV::MINPRI>.
398		659
399	The process will not block as long as any idle watchers are active, and	660	The process will not block as long as any idle watchers are active, and
400	they will be called repeatedly until stopped.	661	they will be called repeatedly until stopped.
401		662
		663	For example, if you have idle watchers at priority C<0> and C<1>, and
		664	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		665	and the I/O watcher will always run when ready. Only when the idle watcher
		666	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		667	pending with the C<0>-priority idle watcher be invoked.
		668
402	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	669	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
403		670
		671	=back
		672
		673
		674	=head3 PREPARE WATCHERS - customise your event loop!
		675
		676	=over 4
404		677
405	=item $w = EV::prepare $callback	678	=item $w = EV::prepare $callback
406		679
407	=item $w = EV::prepare_ns $callback	680	=item $w = EV::prepare_ns $callback
408		681
…		…
411		684
412	See the EV::check watcher, below, for explanations and an example.	685	See the EV::check watcher, below, for explanations and an example.
413		686
414	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	687	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
415		688
		689	=back
		690
		691
		692	=head3 CHECK WATCHERS - customise your event loop even more!
		693
		694	=over 4
416		695
417	=item $w = EV::check $callback	696	=item $w = EV::check $callback
418		697
419	=item $w = EV::check_ns $callback	698	=item $w = EV::check_ns $callback
420		699
…		…
432	# do nothing unless active	711	# do nothing unless active
433	$dispatcher->{_event_queue_h}	712	$dispatcher->{_event_queue_h}
434	or return;	713	or return;
435		714
436	# make the dispatcher handle any outstanding stuff	715	# make the dispatcher handle any outstanding stuff
		716	... not shown
437		717
438	# create an IO watcher for each and every socket	718	# create an I/O watcher for each and every socket
439	@snmp_watcher = (	719	@snmp_watcher = (
440	(map { EV::io $_, EV::READ, sub { } }	720	(map { EV::io $_, EV::READ, sub { } }
441	keys %{ $dispatcher->{_descriptors} }),	721	keys %{ $dispatcher->{_descriptors} }),
		722
		723	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		724	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		725	0, sub { },
442	);	726	);
443
444	# if there are any timeouts, also create a timer
445	push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { }
446	if $event->[Net::SNMP::Dispatcher::_ACTIVE];
447	};	727	};
448		728
449	The callbacks are irrelevant, the only purpose of those watchers is	729	The callbacks are irrelevant (and are not even being called), the
450	to wake up the process as soon as one of those events occurs (socket	730	only purpose of those watchers is to wake up the process as soon as
451	readable, or timer timed out). The corresponding EV::check watcher will then	731	one of those events occurs (socket readable, or timer timed out). The
452	clean up:	732	corresponding EV::check watcher will then clean up:
453		733
454	our $snmp_check = EV::check sub {	734	our $snmp_check = EV::check sub {
455	# destroy all watchers	735	# destroy all watchers
456	@snmp_watcher = ();	736	@snmp_watcher = ();
457		737
458	# make the dispatcher handle any new stuff	738	# make the dispatcher handle any new stuff
		739	... not shown
459	};	740	};
460		741
461	The callbacks of the created watchers will not be called as the watchers	742	The callbacks of the created watchers will not be called as the watchers
462	are destroyed before this cna happen (remember EV::check gets called	743	are destroyed before this cna happen (remember EV::check gets called
463	first).	744	first).
464		745
465	The C<check_ns> variant doesn't start (activate) the newly created watcher.	746	The C<check_ns> variant doesn't start (activate) the newly created watcher.
466		747
467	=back	748	=back
468		749
		750
		751	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		752
		753	Fork watchers are called when a C<fork ()> was detected. The invocation
		754	is done before the event loop blocks next and before C<check> watchers
		755	are being called, and only in the child after the fork.
		756
		757	=over 4
		758
		759	=item $w = EV::fork $callback
		760
		761	=item $w = EV::fork_ns $callback
		762
		763	Call the callback before the event loop is resumed in the child process
		764	after a fork.
		765
		766	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		767
		768	=back
		769
		770
		771	=head1 PERL SIGNALS
		772
		773	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		774	with EV is as the same as any other C library: Perl-signals will only be
		775	handled when Perl runs, which means your signal handler might be invoked
		776	only the next time an event callback is invoked.
		777
		778	The solution is to use EV signal watchers (see C<EV::signal>), which will
		779	ensure proper operations with regards to other event watchers.
		780
		781	If you cannot do this for whatever reason, you can also force a watcher
		782	to be called on every event loop iteration by installing a C<EV::check>
		783	watcher:
		784
		785	my $async_check = EV::check sub { };
		786
		787	This ensures that perl shortly gets into control for a short time, and
		788	also ensures slower overall operation.
		789
469	=head1 THREADS	790	=head1 THREADS
470		791
471	Threads are not supported by this in any way. Perl pseudo-threads is evil	792	Threads are not supported by this module in any way. Perl pseudo-threads
472	stuff and must die.	793	is evil stuff and must die. As soon as Perl gains real threads I will work
		794	on thread support for it.
		795
		796	=head1 FORK
		797
		798	Most of the "improved" event delivering mechanisms of modern operating
		799	systems have quite a few problems with fork(2) (to put it bluntly: it is
		800	not supported and usually destructive). Libev makes it possible to work
		801	around this by having a function that recreates the kernel state after
		802	fork in the child.
		803
		804	On non-win32 platforms, this module requires the pthread_atfork
		805	functionality to do this automatically for you. This function is quite
		806	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		807	negligible, because everything the function currently does is set a flag
		808	that is checked only when the event loop gets used the next time, so when
		809	you do fork but not use EV, the overhead is minimal.
		810
		811	On win32, there is no notion of fork so all this doesn't apply, of course.
473		812
474	=cut	813	=cut
475		814
476	our $DIED = sub {	815	our $DIED = sub {
477	warn "EV: error in callback (ignoring): $@";	816	warn "EV: error in callback (ignoring): $@";
478	};	817	};
479		818
480	default_loop	819	default_loop
481	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';	820	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';
482		821
483	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
484
485	1;	822	1;
486		823
487	=head1 SEE ALSO	824	=head1 SEE ALSO
488		825
489	L<EV::DNS>, L<EV::AnyEvent>.	826	L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as
		827	event loop), L<Coro::EV> (efficient coroutines with EV).
490		828
491	=head1 AUTHOR	829	=head1 AUTHOR
492		830
493	Marc Lehmann <schmorp@schmorp.de>	831	Marc Lehmann <schmorp@schmorp.de>
494	http://home.schmorp.de/	832	http://home.schmorp.de/

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Comparing EV/EV.pm (file contents): Revision 1.29 by root, Tue Nov 6 17:20:42 2007 UTC vs. Revision 1.64 by root, Sat Dec 8 02:55:13 2007 UTC

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Revision 1.29 by root, Tue Nov 6 17:20:42 2007 UTC vs.
Revision 1.64 by root, Sat Dec 8 02:55:13 2007 UTC