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

Comparing EV/EV.pm (file contents):
Revision 1.24 by root, Fri Nov 2 22:03:00 2007 UTC vs.
Revision 1.69 by root, Tue Dec 11 21:04:40 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	# CHILD/PID STATUS CHANGES
		39
38	my $w = EV::signal 3, sub {	40	my $w = EV::child 666, sub {
39	warn "sigquit received (this is GNU/Linux, right?)\n";	41	my ($w, $revents) = @_;
		42	my $status = $w->rstatus;
40	};	43	};
41		44
42	# CHILD/PID STATUS CHANGES	45	# STAT CHANGES
43		46	my $w = EV::stat "/etc/passwd", 10, sub {
44	my $w = EV::child 666, sub {
45	my ($w, $revents, $status) = @_;	47	my ($w, $revents) = @_;
		48	warn $w->path, " has changed somehow.\n";
46	};	49	};
47		50
48	# MAINLOOP	51	# MAINLOOP
49	EV::loop; # loop until EV::loop_done is called	52	EV::loop; # loop until EV::unloop is called or all watchers stop
50	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
51	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
52		55
53	=head1 DESCRIPTION	56	=head1 DESCRIPTION
54		57
55	This module provides an interface to libev	58	This module provides an interface to libev
56	(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.
57		65
58	=cut	66	=cut
59		67
60	package EV;	68	package EV;
61		69
62	use strict;	70	use strict;
63		71
64	BEGIN {	72	BEGIN {
65	our $VERSION = '0.1';	73	our $VERSION = '1.8';
66	use XSLoader;	74	use XSLoader;
67	XSLoader::load "EV", $VERSION;	75	XSLoader::load "EV", $VERSION;
68	}	76	}
69		77
70	@EV::Io::ISA =	78	@EV::IO::ISA =
71	@EV::Timer::ISA =	79	@EV::Timer::ISA =
72	@EV::Periodic::ISA =	80	@EV::Periodic::ISA =
73	@EV::Signal::ISA =	81	@EV::Signal::ISA =
		82	@EV::Child::ISA =
		83	@EV::Stat::ISA =
74	@EV::Idle::ISA =	84	@EV::Idle::ISA =
75	@EV::Prepare::ISA =	85	@EV::Prepare::ISA =
76	@EV::Check::ISA =	86	@EV::Check::ISA =
77	@EV::Child::ISA = "EV::Watcher";	87	@EV::Embed::ISA =
		88	@EV::Fork::ISA =
		89	"EV::Watcher";
78		90
79	=head1 BASIC INTERFACE	91	=head1 BASIC INTERFACE
80		92
81	=over 4	93	=over 4
82		94
83	=item $EV::DIED	95	=item $EV::DIED
84		96
85	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
86	throws an exception (with $@ containing thr error). The default prints an	98	throws an exception (with $@ containing the error). The default prints an
87	informative message and continues.	99	informative message and continues.
88		100
89	If this callback throws an exception it will be silently ignored.	101	If this callback throws an exception it will be silently ignored.
90		102
91	=item $time = EV::time	103	=item $time = EV::time
…		…
96		108
97	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
98	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
99	usually faster then calling EV::time.	111	usually faster then calling EV::time.
100		112
101	=item $method = EV::ev_method	113	=item $method = EV::method
102		114
103	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	115	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
104	or EV::METHOD_EPOLL).	116	or EV::METHOD_EPOLL).
105		117
106	=item EV::loop [$flags]	118	=item EV::loop [$flags]
107		119
108	Begin checking for events and calling callbacks. It returns when a	120	Begin checking for events and calling callbacks. It returns when a
109	callback calls EV::loop_done.	121	callback calls EV::unloop.
110		122
111	The $flags argument can be one of the following:	123	The $flags argument can be one of the following:
112		124
113	0 as above	125	0 as above
114	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	126	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
115	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	127	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
116		128
117	=item EV::loop_done [$how]	129	=item EV::unloop [$how]
118		130
119	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
120	call to EV::loop return.	132	innermost call to EV::loop return.
121		133
122	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
123	fast as possible.	135	fast as possible.
124		136
125	=back	137	=item $count = EV::loop_count
126		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
127	=head2 WATCHER	179	=head2 WATCHER OBJECTS
128		180
129	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
130	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
131	would create an EV::io watcher for that:	183	would create an EV::io watcher for that:
132		184
…		…
141	events.	193	events.
142		194
143	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
144	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
145	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,
146	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
147	(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
148	uses EV::TIMEOUT).	200	uses EV::TIMEOUT).
149		201
150	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
151	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
…		…
157		209
158	Also, all methods changing some aspect of a watcher (->set, ->priority,	210	Also, all methods changing some aspect of a watcher (->set, ->priority,
159	->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,
160	which means pending events get lost.	212	which means pending events get lost.
161		213
162	=head2 WATCHER TYPES	214	=head2 COMMON WATCHER METHODS
163		215
164	Now lets move to the existing watcher types and asociated methods.	216	This section lists methods common to all watchers.
165
166	The following methods are available for all watchers. Then followes a
167	description of each watcher constructor (EV::io, EV::timer, EV::periodic,
168	EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by
169	any type-specific methods (if any).
170		217
171	=over 4	218	=over 4
172		219
173	=item $w->start	220	=item $w->start
174		221
…		…
178		225
179	=item $w->stop	226	=item $w->stop
180		227
181	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
182	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),
183	regardless of wether the watcher was active or not.	230	regardless of whether the watcher was active or not.
184		231
185	=item $bool = $w->is_active	232	=item $bool = $w->is_active
186		233
187	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!");
188		247
189	=item $current_cb = $w->cb	248	=item $current_cb = $w->cb
190		249
191	=item $old_cb = $w->cb ($new_cb)	250	=item $old_cb = $w->cb ($new_cb)
192		251
…		…
201	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
202	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default	261	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
203	-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
204	normalised to the nearest valid priority.	263	normalised to the nearest valid priority.
205		264
206	The default priority of any newly-created weatcher is 0.	265	The default priority of any newly-created watcher is 0.
207		266
		267	Note that the priority semantics have not yet been fleshed out and are
		268	subject to almost certain change.
		269
208	=item $w->trigger ($revents)	270	=item $w->invoke ($revents)
209		271
210	Call the callback now with the given event mask.	272	Call the callback now with the given event mask.
211		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
212		323
213	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	324	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
214		325
215	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	326	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
216		327
217	As long as the returned watcher object is alive, call the C<$callback>	328	As long as the returned watcher object is alive, call the C<$callback>
218	when the events specified in C<$eventmask>.	329	when at least one of events specified in C<$eventmask> occurs.
219		330
220	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:
221		332
222	EV::READ wait until read() wouldn't block anymore	333	EV::READ wait until read() wouldn't block anymore
223	EV::WRITE wait until write() wouldn't block anymore	334	EV::WRITE wait until write() wouldn't block anymore
…		…
239		350
240	=item $old_eventmask = $w->events ($new_eventmask)	351	=item $old_eventmask = $w->events ($new_eventmask)
241		352
242	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.
243		354
		355	=back
		356
		357
		358	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		359
		360	=over 4
244		361
245	=item $w = EV::timer $after, $repeat, $callback	362	=item $w = EV::timer $after, $repeat, $callback
246		363
247	=item $w = EV::timer_ns $after, $repeat, $callback	364	=item $w = EV::timer_ns $after, $repeat, $callback
248		365
249	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	366	Calls the callback after C<$after> seconds (which may be fractional). If
250	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
251	callback returns.	368	value as $after) after the callback returns.
252		369
253	This means that the callback would be called roughly after C<$after>	370	This means that the callback would be called roughly after C<$after>
254	seconds, and then every C<$repeat> seconds. "Roughly" because the time of	371	seconds, and then every C<$repeat> seconds. The timer does his best not
255	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
256	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.
257		375
258	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
259	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
260	clock, the timer will nevertheless run (roughly) the same time.	378	clock, the timer will nevertheless run (roughly) the same time.
261		379
262	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.
263		381
264	=item $w->set ($after, $repeat)	382	=item $w->set ($after, $repeat)
265		383
266	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
267	any time.	385	any time.
268		386
269	=item $w->again	387	=item $w->again
270		388
271	Similar to the C<start> method, but has special semantics for repeating timers:	389	Similar to the C<start> method, but has special semantics for repeating timers:
		390
		391	If the timer is active and non-repeating, it will be stopped.
272		392
273	If the timer is active and repeating, reset the timeout to occur	393	If the timer is active and repeating, reset the timeout to occur
274	C<$repeat> seconds after now.	394	C<$repeat> seconds after now.
275		395
276	If the timer is active and non-repeating, it will be stopped.
277
278	If the timer is in active and repeating, start it.	396	If the timer is inactive and repeating, start it using the repeat value.
279		397
280	Otherwise do nothing.	398	Otherwise do nothing.
281		399
282	This behaviour is useful when you have a timeout for some IO	400	This behaviour is useful when you have a timeout for some IO
283	operation. You create a timer object with the same value for C<$after> and	401	operation. You create a timer object with the same value for C<$after> and
284	C<$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
285	on the timeout.	403	on the timeout.
286		404
		405	=back
287		406
		407
		408	=head3 PERIODIC WATCHERS - to cron or not to cron?
		409
		410	=over 4
		411
288	=item $w = EV::periodic $at, $interval, $callback	412	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
289		413
290	=item $w = EV::periodic_ns $at, $interval, $callback	414	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
291		415
292	Similar to EV::timer, but the time is given as an absolute point in time	416	Similar to EV::timer, but is not based on relative timeouts but on
293	(C<$at>), plus an optional C<$interval>.	417	absolute times. Apart from creating "simple" timers that trigger "at" the
		418	specified time, it can also be used for non-drifting absolute timers and
		419	more complex, cron-like, setups that are not adversely affected by time
		420	jumps (i.e. when the system clock is changed by explicit date -s or other
		421	means such as ntpd). It is also the most complex watcher type in EV.
294		422
295	If the C<$interval> is zero, then the callback will be called at the time	423	It has three distinct "modes":
296	C<$at> if that is in the future, or as soon as possible if it is in the
297	past. It will not automatically repeat.
298		424
299	If the C<$interval> is nonzero, then the watcher will always be scheduled	425	=over 4
300	to time out at the next C<$at + N * $interval> time.
301		426
302	This can be used to schedule a callback to run at very regular intervals,	427	=item * absolute timer ($interval = $reschedule_cb = 0)
303	as long as the processing time is less then the interval (otherwise	428
304	obviously events will be skipped).	429	This time simply fires at the wallclock time C<$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 $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		444
		445	That doesn't mean there will always be 3600 seconds in between triggers,
		446	but only that the the clalback will be called when the system time shows a
		447	full hour (UTC).
305		448
306	Another way to think about it (for the mathematically inclined) is that	449	Another way to think about it (for the mathematically inclined) is that
307	EV::periodic will try to run the callback at the next possible time where	450	EV::periodic will try to run the callback in this mode at the next
308	C<$time = $at (mod $interval)>, regardless of any time jumps.	451	possible time where C<$time = $at (mod $interval)>, regardless of any time
		452	jumps.
309		453
310	This periodic timer is based on "wallclock time", that is, if the clock	454	=item * manual reschedule mode ($reschedule_cb = coderef)
311	changes (C<ntp>, C<date -s> etc.), then the timer will nevertheless run at	455
312	the specified time. This means it will never drift (it might jitter, but	456	In this mode $interval and $at are both being ignored. Instead, each
313	it will not drift).	457	time the periodic watcher gets scheduled, the reschedule callback
		458	($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
314		487
315	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.
316		489
317	=item $w->set ($at, $interval)	490	=item $w->set ($at, $interval, $reschedule_cb)
318		491
319	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
320	any time.	493	any time.
321		494
		495	=item $w->again
		496
		497	Simply stops and starts the watcher again.
		498
		499	=back
		500
		501
		502	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		503
		504	=over 4
322		505
323	=item $w = EV::signal $signal, $callback	506	=item $w = EV::signal $signal, $callback
324		507
325	=item $w = EV::signal_ns $signal, $callback	508	=item $w = EV::signal_ns $signal, $callback
326		509
327	Call the callback when $signal is received (the signal can be specified	510	Call the callback when $signal is received (the signal can be specified by
328	by number or by name, just as with kill or %SIG).	511	number or by name, just as with C<kill> or C<%SIG>).
329		512
330	EV will grab the signal for the process (the kernel only allows one	513	EV will grab the signal for the process (the kernel only allows one
331	component to receive a signal at a time) when you start a signal watcher,	514	component to receive a signal at a time) when you start a signal watcher,
332	and removes it again when you stop it. Perl does the same when you	515	and removes it again when you stop it. Perl does the same when you
333	add/remove callbacks to %SIG, so watch out.	516	add/remove callbacks to C<%SIG>, so watch out.
334		517
335	You can have as many signal watchers per signal as you want.	518	You can have as many signal watchers per signal as you want.
336		519
337	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	520	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
338		521
339	=item $w->set ($signal)	522	=item $w->set ($signal)
340		523
341	Reconfigures the watcher, see the constructor above for details. Can be at	524	Reconfigures the watcher, see the constructor above for details. Can be
342	any time.	525	called at any time.
343		526
344	=item $current_signum = $w->signal	527	=item $current_signum = $w->signal
345		528
346	=item $old_signum = $w->signal ($new_signal)	529	=item $old_signum = $w->signal ($new_signal)
347		530
348	Returns the previously set signal (always as a number not name) and	531	Returns the previously set signal (always as a number not name) and
349	optionally set a new one.	532	optionally set a new one.
350		533
		534	=back
		535
		536
		537	=head3 CHILD WATCHERS - watch out for process status changes
		538
		539	=over 4
351		540
352	=item $w = EV::child $pid, $callback	541	=item $w = EV::child $pid, $callback
353		542
354	=item $w = EV::child_ns $pid, $callback	543	=item $w = EV::child_ns $pid, $callback
355		544
356	Call the callback when a status change for pid C<$pid> (or any pid	545	Call the callback when a status change for pid C<$pid> (or any pid if
357	if C<$pid> is 0) has been received. More precisely: when the process	546	C<$pid> is 0) has been received. More precisely: when the process receives
358	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all	547	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
359	changed/zombie children and call the callback.	548	changed/zombie children and call the callback.
360		549
361	Unlike all other callbacks, this callback will be called with an	550	It is valid (and fully supported) to install a child watcher after a child
362	additional third argument which is the exit status. See the C<waitpid>	551	has exited but before the event loop has started its next iteration (for
363	function for details.	552	example, first you C<fork>, then the new child process might exit, and
		553	only then do you install a child watcher in the parent for the new pid).
364		554
		555	You can access both exit (or tracing) status and pid by using the
		556	C<rstatus> and C<rpid> methods on the watcher object.
		557
365	You can have as many pid watchers per pid as you want.	558	You can have as many pid watchers per pid as you want, they will all be
		559	called.
366		560
367	The C<child_ns> variant doesn't start (activate) the newly created watcher.	561	The C<child_ns> variant doesn't start (activate) the newly created watcher.
368		562
369	=item $w->set ($pid)	563	=item $w->set ($pid)
370		564
371	Reconfigures the watcher, see the constructor above for details. Can be at	565	Reconfigures the watcher, see the constructor above for details. Can be called at
372	any time.	566	any time.
373		567
374	=item $current_pid = $w->pid	568	=item $current_pid = $w->pid
375		569
376	=item $old_pid = $w->pid ($new_pid)	570	=item $old_pid = $w->pid ($new_pid)
377		571
378	Returns the previously set process id and optionally set a new one.	572	Returns the previously set process id and optionally set a new one.
379		573
		574	=item $exit_status = $w->rstatus
		575
		576	Return the exit/wait status (as returned by waitpid, see the waitpid entry
		577	in perlfunc).
		578
		579	=item $pid = $w->rpid
		580
		581	Return the pid of the awaited child (useful when you have installed a
		582	watcher for all pids).
		583
		584	=back
		585
		586
		587	=head3 STAT WATCHERS - did the file attributes just change?
		588
		589	=over 4
		590
		591	=item $w = EV::stat $path, $interval, $callback
		592
		593	=item $w = EV::stat_ns $path, $interval, $callback
		594
		595	Call the callback when a file status change has been detected on
		596	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		597	to "path does not exist" is a status change like any other.
		598
		599	The C<$interval> is a recommended polling interval for systems where
		600	OS-supported change notifications don't exist or are not supported. If
		601	you use C<0> then an unspecified default is used (which is highly
		602	recommended!), which is to be expected to be around five seconds usually.
		603
		604	This watcher type is not meant for massive numbers of stat watchers,
		605	as even with OS-supported change notifications, this can be
		606	resource-intensive.
		607
		608	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		609
		610	=item ... = $w->stat
		611
		612	This call is very similar to the perl C<stat> built-in: It stats (using
		613	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		614	well as EV's idea of the current stat values) to the values found.
		615
		616	In scalar context, a boolean is return indicating success or failure of
		617	the stat. In list context, the same 13-value list as with stat is returned
		618	(except that the blksize and blocks fields are not reliable).
		619
		620	In the case of an error, errno is set to C<ENOENT> (regardless of the
		621	actual error value) and the C<nlink> value is forced to zero (if the stat
		622	was successful then nlink is guaranteed to be non-zero).
		623
		624	See also the next two entries for more info.
		625
		626	=item ... = $w->attr
		627
		628	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		629	the values most recently detected by EV. See the next entry for more info.
		630
		631	=item ... = $w->prev
		632
		633	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		634	the previous set of values, before the change.
		635
		636	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		637	to the values found I<before> a change was detected, while C<< $w->attr >>
		638	returns the values found leading to the change detection. The difference (if any)
		639	between C<prev> and C<attr> is what triggered the callback.
		640
		641	If you did something to the filesystem object and do not want to trigger
		642	yet another change, you can call C<stat> to update EV's idea of what the
		643	current attributes are.
		644
		645	=item $w->set ($path, $interval)
		646
		647	Reconfigures the watcher, see the constructor above for details. Can be
		648	called at any time.
		649
		650	=item $current_path = $w->path
		651
		652	=item $old_path = $w->path ($new_path)
		653
		654	Returns the previously set path and optionally set a new one.
		655
		656	=item $current_interval = $w->interval
		657
		658	=item $old_interval = $w->interval ($new_interval)
		659
		660	Returns the previously set interval and optionally set a new one. Can be
		661	used to query the actual interval used.
		662
		663	=back
		664
		665
		666	=head3 IDLE WATCHERS - when you've got nothing better to do...
		667
		668	=over 4
380		669
381	=item $w = EV::idle $callback	670	=item $w = EV::idle $callback
382		671
383	=item $w = EV::idle_ns $callback	672	=item $w = EV::idle_ns $callback
384		673
385	Call the callback when there are no pending io, timer/periodic, signal or	674	Call the callback when there are no other pending watchers of the same or
386	child events, i.e. when the process is idle.	675	higher priority (excluding check, prepare and other idle watchers of the
		676	same or lower priority, of course). They are called idle watchers because
		677	when the watcher is the highest priority pending event in the process, the
		678	process is considered to be idle at that priority.
		679
		680	If you want a watcher that is only ever called when I<no> other events are
		681	outstanding you have to set the priority to C<EV::MINPRI>.
387		682
388	The process will not block as long as any idle watchers are active, and	683	The process will not block as long as any idle watchers are active, and
389	they will be called repeatedly until stopped.	684	they will be called repeatedly until stopped.
390		685
		686	For example, if you have idle watchers at priority C<0> and C<1>, and
		687	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		688	and the I/O watcher will always run when ready. Only when the idle watcher
		689	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		690	pending with the C<0>-priority idle watcher be invoked.
		691
391	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	692	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
392		693
		694	=back
		695
		696
		697	=head3 PREPARE WATCHERS - customise your event loop!
		698
		699	=over 4
393		700
394	=item $w = EV::prepare $callback	701	=item $w = EV::prepare $callback
395		702
396	=item $w = EV::prepare_ns $callback	703	=item $w = EV::prepare_ns $callback
397		704
…		…
400		707
401	See the EV::check watcher, below, for explanations and an example.	708	See the EV::check watcher, below, for explanations and an example.
402		709
403	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	710	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
404		711
		712	=back
		713
		714
		715	=head3 CHECK WATCHERS - customise your event loop even more!
		716
		717	=over 4
405		718
406	=item $w = EV::check $callback	719	=item $w = EV::check $callback
407		720
408	=item $w = EV::check_ns $callback	721	=item $w = EV::check_ns $callback
409		722
…		…
421	# do nothing unless active	734	# do nothing unless active
422	$dispatcher->{_event_queue_h}	735	$dispatcher->{_event_queue_h}
423	or return;	736	or return;
424		737
425	# make the dispatcher handle any outstanding stuff	738	# make the dispatcher handle any outstanding stuff
		739	... not shown
426		740
427	# create an IO watcher for each and every socket	741	# create an I/O watcher for each and every socket
428	@snmp_watcher = (	742	@snmp_watcher = (
429	(map { EV::io $_, EV::READ, sub { } }	743	(map { EV::io $_, EV::READ, sub { } }
430	keys %{ $dispatcher->{_descriptors} }),	744	keys %{ $dispatcher->{_descriptors} }),
		745
		746	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		747	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		748	0, sub { },
431	);	749	);
432
433	# if there are any timeouts, also create a timer
434	push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { }
435	if $event->[Net::SNMP::Dispatcher::_ACTIVE];
436	};	750	};
437		751
438	The callbacks are irrelevant, the only purpose of those watchers is	752	The callbacks are irrelevant (and are not even being called), the
439	to wake up the process as soon as one of those events occurs (socket	753	only purpose of those watchers is to wake up the process as soon as
440	readable, or timer timed out). The corresponding EV::check watcher will then	754	one of those events occurs (socket readable, or timer timed out). The
441	clean up:	755	corresponding EV::check watcher will then clean up:
442		756
443	our $snmp_check = EV::check sub {	757	our $snmp_check = EV::check sub {
444	# destroy all watchers	758	# destroy all watchers
445	@snmp_watcher = ();	759	@snmp_watcher = ();
446		760
447	# make the dispatcher handle any new stuff	761	# make the dispatcher handle any new stuff
		762	... not shown
448	};	763	};
449		764
450	The callbacks of the created watchers will not be called as the watchers	765	The callbacks of the created watchers will not be called as the watchers
451	are destroyed before this cna happen (remember EV::check gets called	766	are destroyed before this cna happen (remember EV::check gets called
452	first).	767	first).
453		768
454	The C<check_ns> variant doesn't start (activate) the newly created watcher.	769	The C<check_ns> variant doesn't start (activate) the newly created watcher.
455		770
456	=back	771	=back
457		772
		773
		774	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		775
		776	Fork watchers are called when a C<fork ()> was detected. The invocation
		777	is done before the event loop blocks next and before C<check> watchers
		778	are being called, and only in the child after the fork.
		779
		780	=over 4
		781
		782	=item $w = EV::fork $callback
		783
		784	=item $w = EV::fork_ns $callback
		785
		786	Call the callback before the event loop is resumed in the child process
		787	after a fork.
		788
		789	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		790
		791	=back
		792
		793
		794	=head1 PERL SIGNALS
		795
		796	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		797	with EV is as the same as any other C library: Perl-signals will only be
		798	handled when Perl runs, which means your signal handler might be invoked
		799	only the next time an event callback is invoked.
		800
		801	The solution is to use EV signal watchers (see C<EV::signal>), which will
		802	ensure proper operations with regards to other event watchers.
		803
		804	If you cannot do this for whatever reason, you can also force a watcher
		805	to be called on every event loop iteration by installing a C<EV::check>
		806	watcher:
		807
		808	my $async_check = EV::check sub { };
		809
		810	This ensures that perl shortly gets into control for a short time, and
		811	also ensures slower overall operation.
		812
458	=head1 THREADS	813	=head1 THREADS
459		814
460	Threads are not supported by this in any way. Perl pseudo-threads is evil	815	Threads are not supported by this module in any way. Perl pseudo-threads
461	stuff and must die.	816	is evil stuff and must die. As soon as Perl gains real threads I will work
		817	on thread support for it.
		818
		819	=head1 FORK
		820
		821	Most of the "improved" event delivering mechanisms of modern operating
		822	systems have quite a few problems with fork(2) (to put it bluntly: it is
		823	not supported and usually destructive). Libev makes it possible to work
		824	around this by having a function that recreates the kernel state after
		825	fork in the child.
		826
		827	On non-win32 platforms, this module requires the pthread_atfork
		828	functionality to do this automatically for you. This function is quite
		829	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		830	negligible, because everything the function currently does is set a flag
		831	that is checked only when the event loop gets used the next time, so when
		832	you do fork but not use EV, the overhead is minimal.
		833
		834	On win32, there is no notion of fork so all this doesn't apply, of course.
462		835
463	=cut	836	=cut
464		837
465	our $DIED = sub {	838	our $DIED = sub {
466	warn "EV: error in callback (ignoring): $@";	839	warn "EV: error in callback (ignoring): $@";
467	};	840	};
468		841
469	init;	842	default_loop
470		843	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
471	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
472		844
473	1;	845	1;
474		846
475	=head1 SEE ALSO	847	=head1 SEE ALSO
476		848
477	L<EV::DNS>, L<EV::AnyEvent>.	849	L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as
		850	event loop), L<Coro::EV> (efficient coroutines with EV).
478		851
479	=head1 AUTHOR	852	=head1 AUTHOR
480		853
481	Marc Lehmann <schmorp@schmorp.de>	854	Marc Lehmann <schmorp@schmorp.de>
482	http://home.schmorp.de/	855	http://home.schmorp.de/

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Comparing EV/EV.pm (file contents): Revision 1.24 by root, Fri Nov 2 22:03:00 2007 UTC vs. Revision 1.69 by root, Tue Dec 11 21:04:40 2007 UTC

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Revision 1.24 by root, Fri Nov 2 22:03:00 2007 UTC vs.
Revision 1.69 by root, Tue Dec 11 21:04:40 2007 UTC