[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 1.71 by root, Mon Dec 17 07:24:12 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 = '1.86';
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
85	=item $EV::DIED	95	=item $EV::DIED
86		96
87	Must contain a reference to a function that is called when a callback	97	Must contain a reference to a function that is called when a callback
88	throws an exception (with $@ containing thr error). The default prints an	98	throws an exception (with $@ containing the error). The default prints an
89	informative message and continues.	99	informative message and continues.
90		100
91	If this callback throws an exception it will be silently ignored.	101	If this callback throws an exception it will be silently ignored.
92		102
93	=item $time = EV::time	103	=item $time = EV::time
…		…
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	=item EV::feed_fd_event ($fd, $revents)
		166
		167	Feed an event on a file descriptor into EV. EV will react to this call as
		168	if the readyness notifications specified by C<$revents> (a combination of
		169	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		170
		171	=item EV::feed_signal_event ($signal)
		172
		173	Feed a signal event into EV. EV will react to this call as if the signal
		174	specified by C<$signal> had occured.
		175
		176	=back
		177
		178
129	=head2 WATCHER	179	=head2 WATCHER OBJECTS
130		180
131	A watcher is an object that gets created to record your interest in some	181	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	182	event. For instance, if you want to wait for STDIN to become readable, you
133	would create an EV::io watcher for that:	183	would create an EV::io watcher for that:
134		184
…		…
143	events.	193	events.
144		194
145	Each watcher type has its associated bit in revents, so you can use the	195	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	196	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,	197	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	198	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	199	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
150	uses EV::TIMEOUT).	200	uses EV::TIMEOUT).
151		201
152	In the rare case where one wants to create a watcher but not start it at	202	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	203	the same time, each constructor has a variant with a trailing C<_ns> in
…		…
159		209
160	Also, all methods changing some aspect of a watcher (->set, ->priority,	210	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,	211	->fh and so on) automatically stop and start it again if it is active,
162	which means pending events get lost.	212	which means pending events get lost.
163		213
164	=head2 WATCHER TYPES	214	=head2 COMMON WATCHER METHODS
165		215
166	Now lets move to the existing watcher types and asociated methods.	216	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		217
173	=over 4	218	=over 4
174		219
175	=item $w->start	220	=item $w->start
176		221
…		…
180		225
181	=item $w->stop	226	=item $w->stop
182		227
183	Stop a watcher if it is active. Also clear any pending events (events that	228	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),	229	have been received but that didn't yet result in a callback invocation),
185	regardless of wether the watcher was active or not.	230	regardless of whether the watcher was active or not.
186		231
187	=item $bool = $w->is_active	232	=item $bool = $w->is_active
188		233
189	Returns true if the watcher is active, false otherwise.	234	Returns true if the watcher is active, false otherwise.
		235
		236	=item $current_data = $w->data
		237
		238	=item $old_data = $w->data ($new_data)
		239
		240	Queries a freely usable data scalar on the watcher and optionally changes
		241	it. This is a way to associate custom data with a watcher:
		242
		243	my $w = EV::timer 60, 0, sub {
		244	warn $_[0]->data;
		245	};
		246	$w->data ("print me!");
190		247
191	=item $current_cb = $w->cb	248	=item $current_cb = $w->cb
192		249
193	=item $old_cb = $w->cb ($new_cb)	250	=item $old_cb = $w->cb ($new_cb)
194		251
…		…
203	watchers with higher priority will be invoked first. The valid range of	260	watchers with higher priority will be invoked first. The valid range of
204	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default	261	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
205	-2). If the priority is outside this range it will automatically be	262	-2). If the priority is outside this range it will automatically be
206	normalised to the nearest valid priority.	263	normalised to the nearest valid priority.
207		264
208	The default priority of any newly-created weatcher is 0.	265	The default priority of any newly-created watcher is 0.
209		266
		267	Note that the priority semantics have not yet been fleshed out and are
		268	subject to almost certain change.
		269
210	=item $w->trigger ($revents)	270	=item $w->invoke ($revents)
211		271
212	Call the callback now with the given event mask.	272	Call the callback now with the given event mask.
213		273
		274	=item $w->feed_event ($revents)
		275
		276	Feed some events on this watcher into EV. EV will react to this call as if
		277	the watcher had received the given C<$revents> mask.
		278
		279	=item $revents = $w->clear_pending
		280
		281	If the watcher is pending, this function returns clears its pending status
		282	and returns its C<$revents> bitset (as if its callback was invoked). If the
		283	watcher isn't pending it does nothing and returns C<0>.
		284
		285	=item $previous_state = $w->keepalive ($bool)
		286
		287	Normally, C<EV::loop> will return when there are no active watchers
		288	(which is a "deadlock" because no progress can be made anymore). This is
		289	convinient because it allows you to start your watchers (and your jobs),
		290	call C<EV::loop> once and when it returns you know that all your jobs are
		291	finished (or they forgot to register some watchers for their task :).
		292
		293	Sometimes, however, this gets in your way, for example when you the module
		294	that calls C<EV::loop> (usually the main program) is not the same module
		295	as a long-living watcher (for example a DNS client module written by
		296	somebody else even). Then you might want any outstanding requests to be
		297	handled, but you would not want to keep C<EV::loop> from returning just
		298	because you happen to have this long-running UDP port watcher.
		299
		300	In this case you can clear the keepalive status, which means that even
		301	though your watcher is active, it won't keep C<EV::loop> from returning.
		302
		303	The initial value for keepalive is true (enabled), and you cna change it
		304	any time.
		305
		306	Example: Register an I/O watcher for some UDP socket but do not keep the
		307	event loop from running just because of that watcher.
		308
		309	my $udp_socket = ...
		310	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		311	$udp_watcher->keepalive (0);
		312
		313	=back
		314
		315
		316	=head2 WATCHER TYPES
		317
		318	Each of the following subsections describes a single watcher type.
		319
		320	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		321
		322	=over 4
214		323
215	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	324	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
216		325
217	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	326	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
218		327
219	As long as the returned watcher object is alive, call the C<$callback>	328	As long as the returned watcher object is alive, call the C<$callback>
220	when the events specified in C<$eventmask>.	329	when at least one of events specified in C<$eventmask> occurs.
221		330
222	The $eventmask can be one or more of these constants ORed together:	331	The $eventmask can be one or more of these constants ORed together:
223		332
224	EV::READ wait until read() wouldn't block anymore	333	EV::READ wait until read() wouldn't block anymore
225	EV::WRITE wait until write() wouldn't block anymore	334	EV::WRITE wait until write() wouldn't block anymore
…		…
241		350
242	=item $old_eventmask = $w->events ($new_eventmask)	351	=item $old_eventmask = $w->events ($new_eventmask)
243		352
244	Returns the previously set event mask and optionally set a new one.	353	Returns the previously set event mask and optionally set a new one.
245		354
		355	=back
		356
		357
		358	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		359
		360	=over 4
246		361
247	=item $w = EV::timer $after, $repeat, $callback	362	=item $w = EV::timer $after, $repeat, $callback
248		363
249	=item $w = EV::timer_ns $after, $repeat, $callback	364	=item $w = EV::timer_ns $after, $repeat, $callback
250		365
251	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	366	Calls the callback after C<$after> seconds (which may be fractional). If
252	the timer will be restarted (with the $repeat value as $after) after the	367	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
253	callback returns.	368	value as $after) after the callback returns.
254		369
255	This means that the callback would be called roughly after C<$after>	370	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	371	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	372	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.	373	loop iteration, and might drift in other cases. If that isn't acceptable,
		374	look at EV::periodic, which can provide long-term stable timers.
259		375
260	The timer is based on a monotonic clock, that is if somebody is sitting	376	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	377	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.	378	clock, the timer will nevertheless run (roughly) the same time.
263		379
264	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	380	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
265		381
266	=item $w->set ($after, $repeat)	382	=item $w->set ($after, $repeat)
267		383
268	Reconfigures the watcher, see the constructor above for details. Can be at	384	Reconfigures the watcher, see the constructor above for details. Can be called at
269	any time.	385	any time.
270		386
271	=item $w->again	387	=item $w->again
272		388
273	Similar to the C<start> method, but has special semantics for repeating timers:	389	Similar to the C<start> method, but has special semantics for repeating timers:
		390
		391	If the timer is active and non-repeating, it will be stopped.
274		392
275	If the timer is active and repeating, reset the timeout to occur	393	If the timer is active and repeating, reset the timeout to occur
276	C<$repeat> seconds after now.	394	C<$repeat> seconds after now.
277		395
278	If the timer is active and non-repeating, it will be stopped.
279
280	If the timer is in active and repeating, start it.	396	If the timer is inactive and repeating, start it using the repeat value.
281		397
282	Otherwise do nothing.	398	Otherwise do nothing.
283		399
284	This behaviour is useful when you have a timeout for some IO	400	This behaviour is useful when you have a timeout for some IO
285	operation. You create a timer object with the same value for C<$after> and	401	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	402	C<$repeat>, and then, in the read/write watcher, run the C<again> method
287	on the timeout.	403	on the timeout.
288		404
		405	=back
289		406
		407
		408	=head3 PERIODIC WATCHERS - to cron or not to cron?
		409
		410	=over 4
		411
290	=item $w = EV::periodic $at, $interval, $callback	412	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
291		413
292	=item $w = EV::periodic_ns $at, $interval, $callback	414	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
293		415
294	Similar to EV::timer, but the time is given as an absolute point in time	416	Similar to EV::timer, but is not based on relative timeouts but on
295	(C<$at>), plus an optional C<$interval>.	417	absolute times. Apart from creating "simple" timers that trigger "at" the
		418	specified time, it can also be used for non-drifting absolute timers and
		419	more complex, cron-like, setups that are not adversely affected by time
		420	jumps (i.e. when the system clock is changed by explicit date -s or other
		421	means such as ntpd). It is also the most complex watcher type in EV.
296		422
297	If the C<$interval> is zero, then the callback will be called at the time	423	It has three distinct "modes":
298	C<$at> if that is in the future, or as soon as possible if it is in the
299	past. It will not automatically repeat.
300		424
301	If the C<$interval> is nonzero, then the watcher will always be scheduled	425	=over 4
302	to time out at the next C<$at + N * $interval> time.
303		426
304	This can be used to schedule a callback to run at very regular intervals,	427	=item * absolute timer ($interval = $reschedule_cb = 0)
305	as long as the processing time is less then the interval (otherwise	428
306	obviously events will be skipped).	429	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		430	will not adjust when a time jump occurs, that is, if it is to be run
		431	at January 1st 2011 then it will run when the system time reaches or
		432	surpasses this time.
		433
		434	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)
		435
		436	In this mode the watcher will always be scheduled to time out at the
		437	next C<$at + N * $interval> time (for some integer N) and then repeat,
		438	regardless of any time jumps.
		439
		440	This can be used to create timers that do not drift with respect to system
		441	time:
		442
		443	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		444
		445	That doesn't mean there will always be 3600 seconds in between triggers,
		446	but only that the the clalback will be called when the system time shows a
		447	full hour (UTC).
307		448
308	Another way to think about it (for the mathematically inclined) is that	449	Another way to think about it (for the mathematically inclined) is that
309	EV::periodic will try to run the callback at the next possible time where	450	EV::periodic will try to run the callback in this mode at the next
310	C<$time = $at (mod $interval)>, regardless of any time jumps.	451	possible time where C<$time = $at (mod $interval)>, regardless of any time
		452	jumps.
311		453
312	This periodic timer is based on "wallclock time", that is, if the clock	454	=item * manual reschedule mode ($reschedule_cb = coderef)
313	changes (C<ntp>, C<date -s> etc.), then the timer will nevertheless run at	455
314	the specified time. This means it will never drift (it might jitter, but	456	In this mode $interval and $at are both being ignored. Instead, each
315	it will not drift).	457	time the periodic watcher gets scheduled, the reschedule callback
		458	($reschedule_cb) will be called with the watcher as first, and the current
		459	time as second argument.
		460
		461	I<This callback MUST NOT stop or destroy this or any other periodic
		462	watcher, ever>. If you need to stop it, return 1e30 and stop it
		463	afterwards.
		464
		465	It must return the next time to trigger, based on the passed time value
		466	(that is, the lowest time value larger than to the second argument). It
		467	will usually be called just before the callback will be triggered, but
		468	might be called at other times, too.
		469
		470	This can be used to create very complex timers, such as a timer that
		471	triggers on each midnight, local time (actually 24 hours after the last
		472	midnight, to keep the example simple. If you know a way to do it correctly
		473	in about the same space (without requiring elaborate modules), drop me a
		474	note :):
		475
		476	my $daily = EV::periodic 0, 0, sub {
		477	my ($w, $now) = @_;
		478
		479	use Time::Local ();
		480	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		481	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		482	}, sub {
		483	print "it's midnight or likely shortly after, now\n";
		484	};
		485
		486	=back
316		487
317	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	488	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
318		489
319	=item $w->set ($at, $interval)	490	=item $w->set ($at, $interval, $reschedule_cb)
320		491
321	Reconfigures the watcher, see the constructor above for details. Can be at	492	Reconfigures the watcher, see the constructor above for details. Can be called at
322	any time.	493	any time.
323		494
		495	=item $w->again
		496
		497	Simply stops and starts the watcher again.
		498
		499	=item $time = $w->at
		500
		501	Return the time that the watcher is expected to trigger next.
		502
		503	=back
		504
		505
		506	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		507
		508	=over 4
324		509
325	=item $w = EV::signal $signal, $callback	510	=item $w = EV::signal $signal, $callback
326		511
327	=item $w = EV::signal_ns $signal, $callback	512	=item $w = EV::signal_ns $signal, $callback
328		513
329	Call the callback when $signal is received (the signal can be specified	514	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).	515	number or by name, just as with C<kill> or C<%SIG>).
331		516
332	EV will grab the signal for the process (the kernel only allows one	517	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,	518	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	519	and removes it again when you stop it. Perl does the same when you
335	add/remove callbacks to %SIG, so watch out.	520	add/remove callbacks to C<%SIG>, so watch out.
336		521
337	You can have as many signal watchers per signal as you want.	522	You can have as many signal watchers per signal as you want.
338		523
339	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	524	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
340		525
341	=item $w->set ($signal)	526	=item $w->set ($signal)
342		527
343	Reconfigures the watcher, see the constructor above for details. Can be at	528	Reconfigures the watcher, see the constructor above for details. Can be
344	any time.	529	called at any time.
345		530
346	=item $current_signum = $w->signal	531	=item $current_signum = $w->signal
347		532
348	=item $old_signum = $w->signal ($new_signal)	533	=item $old_signum = $w->signal ($new_signal)
349		534
350	Returns the previously set signal (always as a number not name) and	535	Returns the previously set signal (always as a number not name) and
351	optionally set a new one.	536	optionally set a new one.
352		537
		538	=back
		539
		540
		541	=head3 CHILD WATCHERS - watch out for process status changes
		542
		543	=over 4
353		544
354	=item $w = EV::child $pid, $callback	545	=item $w = EV::child $pid, $callback
355		546
356	=item $w = EV::child_ns $pid, $callback	547	=item $w = EV::child_ns $pid, $callback
357		548
358	Call the callback when a status change for pid C<$pid> (or any pid	549	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	550	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	551	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
361	changed/zombie children and call the callback.	552	changed/zombie children and call the callback.
362		553
363	You can access both status and pid by using the C<rstatus> and C<rpid>	554	It is valid (and fully supported) to install a child watcher after a child
364	methods on the watcher object.	555	has exited but before the event loop has started its next iteration (for
		556	example, first you C<fork>, then the new child process might exit, and
		557	only then do you install a child watcher in the parent for the new pid).
365		558
		559	You can access both exit (or tracing) status and pid by using the
		560	C<rstatus> and C<rpid> methods on the watcher object.
		561
366	You can have as many pid watchers per pid as you want.	562	You can have as many pid watchers per pid as you want, they will all be
		563	called.
367		564
368	The C<child_ns> variant doesn't start (activate) the newly created watcher.	565	The C<child_ns> variant doesn't start (activate) the newly created watcher.
369		566
370	=item $w->set ($pid)	567	=item $w->set ($pid)
371		568
372	Reconfigures the watcher, see the constructor above for details. Can be at	569	Reconfigures the watcher, see the constructor above for details. Can be called at
373	any time.	570	any time.
374		571
375	=item $current_pid = $w->pid	572	=item $current_pid = $w->pid
376		573
377	=item $old_pid = $w->pid ($new_pid)	574	=item $old_pid = $w->pid ($new_pid)
…		…
386	=item $pid = $w->rpid	583	=item $pid = $w->rpid
387		584
388	Return the pid of the awaited child (useful when you have installed a	585	Return the pid of the awaited child (useful when you have installed a
389	watcher for all pids).	586	watcher for all pids).
390		587
		588	=back
		589
		590
		591	=head3 STAT WATCHERS - did the file attributes just change?
		592
		593	=over 4
		594
		595	=item $w = EV::stat $path, $interval, $callback
		596
		597	=item $w = EV::stat_ns $path, $interval, $callback
		598
		599	Call the callback when a file status change has been detected on
		600	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		601	to "path does not exist" is a status change like any other.
		602
		603	The C<$interval> is a recommended polling interval for systems where
		604	OS-supported change notifications don't exist or are not supported. If
		605	you use C<0> then an unspecified default is used (which is highly
		606	recommended!), which is to be expected to be around five seconds usually.
		607
		608	This watcher type is not meant for massive numbers of stat watchers,
		609	as even with OS-supported change notifications, this can be
		610	resource-intensive.
		611
		612	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		613
		614	=item ... = $w->stat
		615
		616	This call is very similar to the perl C<stat> built-in: It stats (using
		617	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		618	well as EV's idea of the current stat values) to the values found.
		619
		620	In scalar context, a boolean is return indicating success or failure of
		621	the stat. In list context, the same 13-value list as with stat is returned
		622	(except that the blksize and blocks fields are not reliable).
		623
		624	In the case of an error, errno is set to C<ENOENT> (regardless of the
		625	actual error value) and the C<nlink> value is forced to zero (if the stat
		626	was successful then nlink is guaranteed to be non-zero).
		627
		628	See also the next two entries for more info.
		629
		630	=item ... = $w->attr
		631
		632	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		633	the values most recently detected by EV. See the next entry for more info.
		634
		635	=item ... = $w->prev
		636
		637	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		638	the previous set of values, before the change.
		639
		640	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		641	to the values found I<before> a change was detected, while C<< $w->attr >>
		642	returns the values found leading to the change detection. The difference (if any)
		643	between C<prev> and C<attr> is what triggered the callback.
		644
		645	If you did something to the filesystem object and do not want to trigger
		646	yet another change, you can call C<stat> to update EV's idea of what the
		647	current attributes are.
		648
		649	=item $w->set ($path, $interval)
		650
		651	Reconfigures the watcher, see the constructor above for details. Can be
		652	called at any time.
		653
		654	=item $current_path = $w->path
		655
		656	=item $old_path = $w->path ($new_path)
		657
		658	Returns the previously set path and optionally set a new one.
		659
		660	=item $current_interval = $w->interval
		661
		662	=item $old_interval = $w->interval ($new_interval)
		663
		664	Returns the previously set interval and optionally set a new one. Can be
		665	used to query the actual interval used.
		666
		667	=back
		668
		669
		670	=head3 IDLE WATCHERS - when you've got nothing better to do...
		671
		672	=over 4
391		673
392	=item $w = EV::idle $callback	674	=item $w = EV::idle $callback
393		675
394	=item $w = EV::idle_ns $callback	676	=item $w = EV::idle_ns $callback
395		677
396	Call the callback when there are no pending io, timer/periodic, signal or	678	Call the callback when there are no other pending watchers of the same or
397	child events, i.e. when the process is idle.	679	higher priority (excluding check, prepare and other idle watchers of the
		680	same or lower priority, of course). They are called idle watchers because
		681	when the watcher is the highest priority pending event in the process, the
		682	process is considered to be idle at that priority.
		683
		684	If you want a watcher that is only ever called when I<no> other events are
		685	outstanding you have to set the priority to C<EV::MINPRI>.
398		686
399	The process will not block as long as any idle watchers are active, and	687	The process will not block as long as any idle watchers are active, and
400	they will be called repeatedly until stopped.	688	they will be called repeatedly until stopped.
401		689
		690	For example, if you have idle watchers at priority C<0> and C<1>, and
		691	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		692	and the I/O watcher will always run when ready. Only when the idle watcher
		693	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		694	pending with the C<0>-priority idle watcher be invoked.
		695
402	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	696	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
403		697
		698	=back
		699
		700
		701	=head3 PREPARE WATCHERS - customise your event loop!
		702
		703	=over 4
404		704
405	=item $w = EV::prepare $callback	705	=item $w = EV::prepare $callback
406		706
407	=item $w = EV::prepare_ns $callback	707	=item $w = EV::prepare_ns $callback
408		708
…		…
411		711
412	See the EV::check watcher, below, for explanations and an example.	712	See the EV::check watcher, below, for explanations and an example.
413		713
414	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	714	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
415		715
		716	=back
		717
		718
		719	=head3 CHECK WATCHERS - customise your event loop even more!
		720
		721	=over 4
416		722
417	=item $w = EV::check $callback	723	=item $w = EV::check $callback
418		724
419	=item $w = EV::check_ns $callback	725	=item $w = EV::check_ns $callback
420		726
…		…
432	# do nothing unless active	738	# do nothing unless active
433	$dispatcher->{_event_queue_h}	739	$dispatcher->{_event_queue_h}
434	or return;	740	or return;
435		741
436	# make the dispatcher handle any outstanding stuff	742	# make the dispatcher handle any outstanding stuff
		743	... not shown
437		744
438	# create an IO watcher for each and every socket	745	# create an I/O watcher for each and every socket
439	@snmp_watcher = (	746	@snmp_watcher = (
440	(map { EV::io $_, EV::READ, sub { } }	747	(map { EV::io $_, EV::READ, sub { } }
441	keys %{ $dispatcher->{_descriptors} }),	748	keys %{ $dispatcher->{_descriptors} }),
		749
		750	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		751	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		752	0, sub { },
442	);	753	);
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	};	754	};
448		755
449	The callbacks are irrelevant, the only purpose of those watchers is	756	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	757	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	758	one of those events occurs (socket readable, or timer timed out). The
452	clean up:	759	corresponding EV::check watcher will then clean up:
453		760
454	our $snmp_check = EV::check sub {	761	our $snmp_check = EV::check sub {
455	# destroy all watchers	762	# destroy all watchers
456	@snmp_watcher = ();	763	@snmp_watcher = ();
457		764
458	# make the dispatcher handle any new stuff	765	# make the dispatcher handle any new stuff
		766	... not shown
459	};	767	};
460		768
461	The callbacks of the created watchers will not be called as the watchers	769	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	770	are destroyed before this cna happen (remember EV::check gets called
463	first).	771	first).
464		772
465	The C<check_ns> variant doesn't start (activate) the newly created watcher.	773	The C<check_ns> variant doesn't start (activate) the newly created watcher.
466		774
467	=back	775	=back
468		776
		777
		778	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		779
		780	Fork watchers are called when a C<fork ()> was detected. The invocation
		781	is done before the event loop blocks next and before C<check> watchers
		782	are being called, and only in the child after the fork.
		783
		784	=over 4
		785
		786	=item $w = EV::fork $callback
		787
		788	=item $w = EV::fork_ns $callback
		789
		790	Call the callback before the event loop is resumed in the child process
		791	after a fork.
		792
		793	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		794
		795	=back
		796
		797
		798	=head1 PERL SIGNALS
		799
		800	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		801	with EV is as the same as any other C library: Perl-signals will only be
		802	handled when Perl runs, which means your signal handler might be invoked
		803	only the next time an event callback is invoked.
		804
		805	The solution is to use EV signal watchers (see C<EV::signal>), which will
		806	ensure proper operations with regards to other event watchers.
		807
		808	If you cannot do this for whatever reason, you can also force a watcher
		809	to be called on every event loop iteration by installing a C<EV::check>
		810	watcher:
		811
		812	my $async_check = EV::check sub { };
		813
		814	This ensures that perl shortly gets into control for a short time, and
		815	also ensures slower overall operation.
		816
469	=head1 THREADS	817	=head1 THREADS
470		818
471	Threads are not supported by this in any way. Perl pseudo-threads is evil	819	Threads are not supported by this module in any way. Perl pseudo-threads
472	stuff and must die.	820	is evil stuff and must die. As soon as Perl gains real threads I will work
		821	on thread support for it.
		822
		823	=head1 FORK
		824
		825	Most of the "improved" event delivering mechanisms of modern operating
		826	systems have quite a few problems with fork(2) (to put it bluntly: it is
		827	not supported and usually destructive). Libev makes it possible to work
		828	around this by having a function that recreates the kernel state after
		829	fork in the child.
		830
		831	On non-win32 platforms, this module requires the pthread_atfork
		832	functionality to do this automatically for you. This function is quite
		833	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		834	negligible, because everything the function currently does is set a flag
		835	that is checked only when the event loop gets used the next time, so when
		836	you do fork but not use EV, the overhead is minimal.
		837
		838	On win32, there is no notion of fork so all this doesn't apply, of course.
473		839
474	=cut	840	=cut
475		841
476	our $DIED = sub {	842	our $DIED = sub {
477	warn "EV: error in callback (ignoring): $@";	843	warn "EV: error in callback (ignoring): $@";
478	};	844	};
479		845
480	default_loop	846	default_loop
481	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';	847	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
482
483	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
484		848
485	1;	849	1;
486		850
487	=head1 SEE ALSO	851	=head1 SEE ALSO
488		852
489	L<EV::DNS>, L<EV::AnyEvent>.	853	L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as
		854	event loop), L<Coro::EV> (efficient coroutines with EV).
490		855
491	=head1 AUTHOR	856	=head1 AUTHOR
492		857
493	Marc Lehmann <schmorp@schmorp.de>	858	Marc Lehmann <schmorp@schmorp.de>
494	http://home.schmorp.de/	859	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 1.71 by root, Mon Dec 17 07:24:12 2007 UTC

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Revision 1.29 by root, Tue Nov 6 17:20:42 2007 UTC vs.
Revision 1.71 by root, Mon Dec 17 07:24:12 2007 UTC