[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 1.72 by root, Thu Dec 20 07:12:57 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 = '2.0';
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";
		90
		91	@EV::Loop::Default::ISA = "EV::Loop";
80		92
81	=head1 BASIC INTERFACE	93	=head1 BASIC INTERFACE
82		94
83	=over 4	95	=over 4
84		96
85	=item $EV::DIED	97	=item $EV::DIED
86		98
87	Must contain a reference to a function that is called when a callback	99	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	100	throws an exception (with $@ containing the error). The default prints an
89	informative message and continues.	101	informative message and continues.
90		102
91	If this callback throws an exception it will be silently ignored.	103	If this callback throws an exception it will be silently ignored.
92		104
93	=item $time = EV::time	105	=item $time = EV::time
…		…
98		110
99	Returns the time the last event loop iteration has been started. This	111	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	112	is the time that (relative) timers are based on, and refering to it is
101	usually faster then calling EV::time.	113	usually faster then calling EV::time.
102		114
103	=item $method = EV::ev_method	115	=item $method = EV::method
104		116
105	Returns an integer describing the backend used by libev (EV::METHOD_SELECT	117	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
106	or EV::METHOD_EPOLL).	118	or EV::METHOD_EPOLL).
107		119
108	=item EV::loop [$flags]	120	=item EV::loop [$flags]
109		121
110	Begin checking for events and calling callbacks. It returns when a	122	Begin checking for events and calling callbacks. It returns when a
111	callback calls EV::loop_done.	123	callback calls EV::unloop.
112		124
113	The $flags argument can be one of the following:	125	The $flags argument can be one of the following:
114		126
115	0 as above	127	0 as above
116	EV::LOOP_ONESHOT block at most once (wait, but do not loop)	128	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
117	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)	129	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
118		130
119	=item EV::loop_done [$how]	131	=item EV::unloop [$how]
120		132
121	When called with no arguments or an argument of 1, makes the innermost	133	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
122	call to EV::loop return.	134	innermost call to EV::loop return.
123		135
124	When called with an agrument of 2, all calls to EV::loop will return as	136	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
125	fast as possible.	137	fast as possible.
126		138
127	=back	139	=item $count = EV::loop_count
128		140
		141	Return the number of times the event loop has polled for new
		142	events. Sometiems useful as a generation counter.
		143
		144	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		145
		146	This function rolls together an I/O and a timer watcher for a single
		147	one-shot event without the need for managing a watcher object.
		148
		149	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		150	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		151	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		152	you do not want to wait for some I/O event, specify C<undef> for
		153	C<$fh_or_undef> and C<0> for C<$events>).
		154
		155	If timeout is C<undef> or negative, then there will be no
		156	timeout. Otherwise a EV::timer with this value will be started.
		157
		158	When an error occurs or either the timeout or I/O watcher triggers, then
		159	the callback will be called with the received event set (in general
		160	you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>,
		161	C<EV::WRITE> and C<EV::TIMEOUT>).
		162
		163	EV::once doesn't return anything: the watchers stay active till either
		164	of them triggers, then they will be stopped and freed, and the callback
		165	invoked.
		166
		167	=item EV::feed_fd_event ($fd, $revents)
		168
		169	Feed an event on a file descriptor into EV. EV will react to this call as
		170	if the readyness notifications specified by C<$revents> (a combination of
		171	C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>.
		172
		173	=item EV::feed_signal_event ($signal)
		174
		175	Feed a signal event into EV. EV will react to this call as if the signal
		176	specified by C<$signal> had occured.
		177
		178	=back
		179
		180
129	=head2 WATCHER	181	=head2 WATCHER OBJECTS
130		182
131	A watcher is an object that gets created to record your interest in some	183	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	184	event. For instance, if you want to wait for STDIN to become readable, you
133	would create an EV::io watcher for that:	185	would create an EV::io watcher for that:
134		186
…		…
143	events.	195	events.
144		196
145	Each watcher type has its associated bit in revents, so you can use the	197	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	198	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,	199	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	200	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	201	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
150	uses EV::TIMEOUT).	202	uses EV::TIMEOUT).
151		203
152	In the rare case where one wants to create a watcher but not start it at	204	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	205	the same time, each constructor has a variant with a trailing C<_ns> in
…		…
159		211
160	Also, all methods changing some aspect of a watcher (->set, ->priority,	212	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,	213	->fh and so on) automatically stop and start it again if it is active,
162	which means pending events get lost.	214	which means pending events get lost.
163		215
164	=head2 WATCHER TYPES	216	=head2 COMMON WATCHER METHODS
165		217
166	Now lets move to the existing watcher types and asociated methods.	218	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		219
173	=over 4	220	=over 4
174		221
175	=item $w->start	222	=item $w->start
176		223
…		…
180		227
181	=item $w->stop	228	=item $w->stop
182		229
183	Stop a watcher if it is active. Also clear any pending events (events that	230	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),	231	have been received but that didn't yet result in a callback invocation),
185	regardless of wether the watcher was active or not.	232	regardless of whether the watcher was active or not.
186		233
187	=item $bool = $w->is_active	234	=item $bool = $w->is_active
188		235
189	Returns true if the watcher is active, false otherwise.	236	Returns true if the watcher is active, false otherwise.
		237
		238	=item $current_data = $w->data
		239
		240	=item $old_data = $w->data ($new_data)
		241
		242	Queries a freely usable data scalar on the watcher and optionally changes
		243	it. This is a way to associate custom data with a watcher:
		244
		245	my $w = EV::timer 60, 0, sub {
		246	warn $_[0]->data;
		247	};
		248	$w->data ("print me!");
190		249
191	=item $current_cb = $w->cb	250	=item $current_cb = $w->cb
192		251
193	=item $old_cb = $w->cb ($new_cb)	252	=item $old_cb = $w->cb ($new_cb)
194		253
…		…
203	watchers with higher priority will be invoked first. The valid range of	262	watchers with higher priority will be invoked first. The valid range of
204	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default	263	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
205	-2). If the priority is outside this range it will automatically be	264	-2). If the priority is outside this range it will automatically be
206	normalised to the nearest valid priority.	265	normalised to the nearest valid priority.
207		266
208	The default priority of any newly-created weatcher is 0.	267	The default priority of any newly-created watcher is 0.
209		268
		269	Note that the priority semantics have not yet been fleshed out and are
		270	subject to almost certain change.
		271
210	=item $w->trigger ($revents)	272	=item $w->invoke ($revents)
211		273
212	Call the callback now with the given event mask.	274	Call the callback now with the given event mask.
213		275
		276	=item $w->feed_event ($revents)
		277
		278	Feed some events on this watcher into EV. EV will react to this call as if
		279	the watcher had received the given C<$revents> mask.
		280
		281	=item $revents = $w->clear_pending
		282
		283	If the watcher is pending, this function returns clears its pending status
		284	and returns its C<$revents> bitset (as if its callback was invoked). If the
		285	watcher isn't pending it does nothing and returns C<0>.
		286
		287	=item $previous_state = $w->keepalive ($bool)
		288
		289	Normally, C<EV::loop> will return when there are no active watchers
		290	(which is a "deadlock" because no progress can be made anymore). This is
		291	convinient because it allows you to start your watchers (and your jobs),
		292	call C<EV::loop> once and when it returns you know that all your jobs are
		293	finished (or they forgot to register some watchers for their task :).
		294
		295	Sometimes, however, this gets in your way, for example when you the module
		296	that calls C<EV::loop> (usually the main program) is not the same module
		297	as a long-living watcher (for example a DNS client module written by
		298	somebody else even). Then you might want any outstanding requests to be
		299	handled, but you would not want to keep C<EV::loop> from returning just
		300	because you happen to have this long-running UDP port watcher.
		301
		302	In this case you can clear the keepalive status, which means that even
		303	though your watcher is active, it won't keep C<EV::loop> from returning.
		304
		305	The initial value for keepalive is true (enabled), and you cna change it
		306	any time.
		307
		308	Example: Register an I/O watcher for some UDP socket but do not keep the
		309	event loop from running just because of that watcher.
		310
		311	my $udp_socket = ...
		312	my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... };
		313	$udp_watcher->keepalive (0);
		314
		315	=back
		316
		317
		318	=head2 WATCHER TYPES
		319
		320	Each of the following subsections describes a single watcher type.
		321
		322	=head3 I/O WATCHERS - is this file descriptor readable or writable?
		323
		324	=over 4
214		325
215	=item $w = EV::io $fileno_or_fh, $eventmask, $callback	326	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
216		327
217	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback	328	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
218		329
219	As long as the returned watcher object is alive, call the C<$callback>	330	As long as the returned watcher object is alive, call the C<$callback>
220	when the events specified in C<$eventmask>.	331	when at least one of events specified in C<$eventmask> occurs.
221		332
222	The $eventmask can be one or more of these constants ORed together:	333	The $eventmask can be one or more of these constants ORed together:
223		334
224	EV::READ wait until read() wouldn't block anymore	335	EV::READ wait until read() wouldn't block anymore
225	EV::WRITE wait until write() wouldn't block anymore	336	EV::WRITE wait until write() wouldn't block anymore
…		…
241		352
242	=item $old_eventmask = $w->events ($new_eventmask)	353	=item $old_eventmask = $w->events ($new_eventmask)
243		354
244	Returns the previously set event mask and optionally set a new one.	355	Returns the previously set event mask and optionally set a new one.
245		356
		357	=back
		358
		359
		360	=head3 TIMER WATCHERS - relative and optionally repeating timeouts
		361
		362	=over 4
246		363
247	=item $w = EV::timer $after, $repeat, $callback	364	=item $w = EV::timer $after, $repeat, $callback
248		365
249	=item $w = EV::timer_ns $after, $repeat, $callback	366	=item $w = EV::timer_ns $after, $repeat, $callback
250		367
251	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,	368	Calls the callback after C<$after> seconds (which may be fractional). If
252	the timer will be restarted (with the $repeat value as $after) after the	369	C<$repeat> is non-zero, the timer will be restarted (with the $repeat
253	callback returns.	370	value as $after) after the callback returns.
254		371
255	This means that the callback would be called roughly after C<$after>	372	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	373	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	374	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.	375	loop iteration, and might drift in other cases. If that isn't acceptable,
		376	look at EV::periodic, which can provide long-term stable timers.
259		377
260	The timer is based on a monotonic clock, that is if somebody is sitting	378	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	379	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.	380	clock, the timer will nevertheless run (roughly) the same time.
263		381
264	The C<timer_ns> variant doesn't start (activate) the newly created watcher.	382	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
265		383
266	=item $w->set ($after, $repeat)	384	=item $w->set ($after, $repeat)
267		385
268	Reconfigures the watcher, see the constructor above for details. Can be at	386	Reconfigures the watcher, see the constructor above for details. Can be called at
269	any time.	387	any time.
270		388
271	=item $w->again	389	=item $w->again
272		390
273	Similar to the C<start> method, but has special semantics for repeating timers:	391	Similar to the C<start> method, but has special semantics for repeating timers:
		392
		393	If the timer is active and non-repeating, it will be stopped.
274		394
275	If the timer is active and repeating, reset the timeout to occur	395	If the timer is active and repeating, reset the timeout to occur
276	C<$repeat> seconds after now.	396	C<$repeat> seconds after now.
277		397
278	If the timer is active and non-repeating, it will be stopped.
279
280	If the timer is in active and repeating, start it.	398	If the timer is inactive and repeating, start it using the repeat value.
281		399
282	Otherwise do nothing.	400	Otherwise do nothing.
283		401
284	This behaviour is useful when you have a timeout for some IO	402	This behaviour is useful when you have a timeout for some IO
285	operation. You create a timer object with the same value for C<$after> and	403	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	404	C<$repeat>, and then, in the read/write watcher, run the C<again> method
287	on the timeout.	405	on the timeout.
288		406
		407	=back
289		408
		409
		410	=head3 PERIODIC WATCHERS - to cron or not to cron?
		411
		412	=over 4
		413
290	=item $w = EV::periodic $at, $interval, $callback	414	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
291		415
292	=item $w = EV::periodic_ns $at, $interval, $callback	416	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
293		417
294	Similar to EV::timer, but the time is given as an absolute point in time	418	Similar to EV::timer, but is not based on relative timeouts but on
295	(C<$at>), plus an optional C<$interval>.	419	absolute times. Apart from creating "simple" timers that trigger "at" the
		420	specified time, it can also be used for non-drifting absolute timers and
		421	more complex, cron-like, setups that are not adversely affected by time
		422	jumps (i.e. when the system clock is changed by explicit date -s or other
		423	means such as ntpd). It is also the most complex watcher type in EV.
296		424
297	If the C<$interval> is zero, then the callback will be called at the time	425	It has three distinct "modes":
298	C<$at> if that is in the future, or as soon as possible if it is in the
299	past. It will not automatically repeat.
300		426
301	If the C<$interval> is nonzero, then the watcher will always be scheduled	427	=over 4
302	to time out at the next C<$at + N * $interval> time.
303		428
304	This can be used to schedule a callback to run at very regular intervals,	429	=item * absolute timer ($interval = $reschedule_cb = 0)
305	as long as the processing time is less then the interval (otherwise	430
306	obviously events will be skipped).	431	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		432	will not adjust when a time jump occurs, that is, if it is to be run
		433	at January 1st 2011 then it will run when the system time reaches or
		434	surpasses this time.
		435
		436	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)
		437
		438	In this mode the watcher will always be scheduled to time out at the
		439	next C<$at + N * $interval> time (for some integer N) and then repeat,
		440	regardless of any time jumps.
		441
		442	This can be used to create timers that do not drift with respect to system
		443	time:
		444
		445	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		446
		447	That doesn't mean there will always be 3600 seconds in between triggers,
		448	but only that the the clalback will be called when the system time shows a
		449	full hour (UTC).
307		450
308	Another way to think about it (for the mathematically inclined) is that	451	Another way to think about it (for the mathematically inclined) is that
309	EV::periodic will try to run the callback at the next possible time where	452	EV::periodic will try to run the callback in this mode at the next
310	C<$time = $at (mod $interval)>, regardless of any time jumps.	453	possible time where C<$time = $at (mod $interval)>, regardless of any time
		454	jumps.
311		455
312	This periodic timer is based on "wallclock time", that is, if the clock	456	=item * manual reschedule mode ($reschedule_cb = coderef)
313	changes (C<ntp>, C<date -s> etc.), then the timer will nevertheless run at	457
314	the specified time. This means it will never drift (it might jitter, but	458	In this mode $interval and $at are both being ignored. Instead, each
315	it will not drift).	459	time the periodic watcher gets scheduled, the reschedule callback
		460	($reschedule_cb) will be called with the watcher as first, and the current
		461	time as second argument.
		462
		463	I<This callback MUST NOT stop or destroy this or any other periodic
		464	watcher, ever>. If you need to stop it, return 1e30 and stop it
		465	afterwards.
		466
		467	It must return the next time to trigger, based on the passed time value
		468	(that is, the lowest time value larger than to the second argument). It
		469	will usually be called just before the callback will be triggered, but
		470	might be called at other times, too.
		471
		472	This can be used to create very complex timers, such as a timer that
		473	triggers on each midnight, local time (actually 24 hours after the last
		474	midnight, to keep the example simple. If you know a way to do it correctly
		475	in about the same space (without requiring elaborate modules), drop me a
		476	note :):
		477
		478	my $daily = EV::periodic 0, 0, sub {
		479	my ($w, $now) = @_;
		480
		481	use Time::Local ();
		482	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		483	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		484	}, sub {
		485	print "it's midnight or likely shortly after, now\n";
		486	};
		487
		488	=back
316		489
317	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.	490	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
318		491
319	=item $w->set ($at, $interval)	492	=item $w->set ($at, $interval, $reschedule_cb)
320		493
321	Reconfigures the watcher, see the constructor above for details. Can be at	494	Reconfigures the watcher, see the constructor above for details. Can be called at
322	any time.	495	any time.
323		496
		497	=item $w->again
		498
		499	Simply stops and starts the watcher again.
		500
		501	=item $time = $w->at
		502
		503	Return the time that the watcher is expected to trigger next.
		504
		505	=back
		506
		507
		508	=head3 SIGNAL WATCHERS - signal me when a signal gets signalled!
		509
		510	=over 4
324		511
325	=item $w = EV::signal $signal, $callback	512	=item $w = EV::signal $signal, $callback
326		513
327	=item $w = EV::signal_ns $signal, $callback	514	=item $w = EV::signal_ns $signal, $callback
328		515
329	Call the callback when $signal is received (the signal can be specified	516	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).	517	number or by name, just as with C<kill> or C<%SIG>).
331		518
332	EV will grab the signal for the process (the kernel only allows one	519	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,	520	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	521	and removes it again when you stop it. Perl does the same when you
335	add/remove callbacks to %SIG, so watch out.	522	add/remove callbacks to C<%SIG>, so watch out.
336		523
337	You can have as many signal watchers per signal as you want.	524	You can have as many signal watchers per signal as you want.
338		525
339	The C<signal_ns> variant doesn't start (activate) the newly created watcher.	526	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
340		527
341	=item $w->set ($signal)	528	=item $w->set ($signal)
342		529
343	Reconfigures the watcher, see the constructor above for details. Can be at	530	Reconfigures the watcher, see the constructor above for details. Can be
344	any time.	531	called at any time.
345		532
346	=item $current_signum = $w->signal	533	=item $current_signum = $w->signal
347		534
348	=item $old_signum = $w->signal ($new_signal)	535	=item $old_signum = $w->signal ($new_signal)
349		536
350	Returns the previously set signal (always as a number not name) and	537	Returns the previously set signal (always as a number not name) and
351	optionally set a new one.	538	optionally set a new one.
352		539
		540	=back
		541
		542
		543	=head3 CHILD WATCHERS - watch out for process status changes
		544
		545	=over 4
353		546
354	=item $w = EV::child $pid, $callback	547	=item $w = EV::child $pid, $callback
355		548
356	=item $w = EV::child_ns $pid, $callback	549	=item $w = EV::child_ns $pid, $callback
357		550
358	Call the callback when a status change for pid C<$pid> (or any pid	551	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	552	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	553	a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all
361	changed/zombie children and call the callback.	554	changed/zombie children and call the callback.
362		555
363	You can access both status and pid by using the C<rstatus> and C<rpid>	556	It is valid (and fully supported) to install a child watcher after a child
364	methods on the watcher object.	557	has exited but before the event loop has started its next iteration (for
		558	example, first you C<fork>, then the new child process might exit, and
		559	only then do you install a child watcher in the parent for the new pid).
365		560
		561	You can access both exit (or tracing) status and pid by using the
		562	C<rstatus> and C<rpid> methods on the watcher object.
		563
366	You can have as many pid watchers per pid as you want.	564	You can have as many pid watchers per pid as you want, they will all be
		565	called.
367		566
368	The C<child_ns> variant doesn't start (activate) the newly created watcher.	567	The C<child_ns> variant doesn't start (activate) the newly created watcher.
369		568
370	=item $w->set ($pid)	569	=item $w->set ($pid)
371		570
372	Reconfigures the watcher, see the constructor above for details. Can be at	571	Reconfigures the watcher, see the constructor above for details. Can be called at
373	any time.	572	any time.
374		573
375	=item $current_pid = $w->pid	574	=item $current_pid = $w->pid
376		575
377	=item $old_pid = $w->pid ($new_pid)	576	=item $old_pid = $w->pid ($new_pid)
…		…
386	=item $pid = $w->rpid	585	=item $pid = $w->rpid
387		586
388	Return the pid of the awaited child (useful when you have installed a	587	Return the pid of the awaited child (useful when you have installed a
389	watcher for all pids).	588	watcher for all pids).
390		589
		590	=back
		591
		592
		593	=head3 STAT WATCHERS - did the file attributes just change?
		594
		595	=over 4
		596
		597	=item $w = EV::stat $path, $interval, $callback
		598
		599	=item $w = EV::stat_ns $path, $interval, $callback
		600
		601	Call the callback when a file status change has been detected on
		602	C<$path>. The C<$path> does not need to exist, changing from "path exists"
		603	to "path does not exist" is a status change like any other.
		604
		605	The C<$interval> is a recommended polling interval for systems where
		606	OS-supported change notifications don't exist or are not supported. If
		607	you use C<0> then an unspecified default is used (which is highly
		608	recommended!), which is to be expected to be around five seconds usually.
		609
		610	This watcher type is not meant for massive numbers of stat watchers,
		611	as even with OS-supported change notifications, this can be
		612	resource-intensive.
		613
		614	The C<stat_ns> variant doesn't start (activate) the newly created watcher.
		615
		616	=item ... = $w->stat
		617
		618	This call is very similar to the perl C<stat> built-in: It stats (using
		619	C<lstat>) the path specified in the watcher and sets perls stat cache (as
		620	well as EV's idea of the current stat values) to the values found.
		621
		622	In scalar context, a boolean is return indicating success or failure of
		623	the stat. In list context, the same 13-value list as with stat is returned
		624	(except that the blksize and blocks fields are not reliable).
		625
		626	In the case of an error, errno is set to C<ENOENT> (regardless of the
		627	actual error value) and the C<nlink> value is forced to zero (if the stat
		628	was successful then nlink is guaranteed to be non-zero).
		629
		630	See also the next two entries for more info.
		631
		632	=item ... = $w->attr
		633
		634	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		635	the values most recently detected by EV. See the next entry for more info.
		636
		637	=item ... = $w->prev
		638
		639	Just like C<< $w->stat >>, but without the initial stat'ing: this returns
		640	the previous set of values, before the change.
		641
		642	That is, when the watcher callback is invoked, C<< $w->prev >> will be set
		643	to the values found I<before> a change was detected, while C<< $w->attr >>
		644	returns the values found leading to the change detection. The difference (if any)
		645	between C<prev> and C<attr> is what triggered the callback.
		646
		647	If you did something to the filesystem object and do not want to trigger
		648	yet another change, you can call C<stat> to update EV's idea of what the
		649	current attributes are.
		650
		651	=item $w->set ($path, $interval)
		652
		653	Reconfigures the watcher, see the constructor above for details. Can be
		654	called at any time.
		655
		656	=item $current_path = $w->path
		657
		658	=item $old_path = $w->path ($new_path)
		659
		660	Returns the previously set path and optionally set a new one.
		661
		662	=item $current_interval = $w->interval
		663
		664	=item $old_interval = $w->interval ($new_interval)
		665
		666	Returns the previously set interval and optionally set a new one. Can be
		667	used to query the actual interval used.
		668
		669	=back
		670
		671
		672	=head3 IDLE WATCHERS - when you've got nothing better to do...
		673
		674	=over 4
391		675
392	=item $w = EV::idle $callback	676	=item $w = EV::idle $callback
393		677
394	=item $w = EV::idle_ns $callback	678	=item $w = EV::idle_ns $callback
395		679
396	Call the callback when there are no pending io, timer/periodic, signal or	680	Call the callback when there are no other pending watchers of the same or
397	child events, i.e. when the process is idle.	681	higher priority (excluding check, prepare and other idle watchers of the
		682	same or lower priority, of course). They are called idle watchers because
		683	when the watcher is the highest priority pending event in the process, the
		684	process is considered to be idle at that priority.
		685
		686	If you want a watcher that is only ever called when I<no> other events are
		687	outstanding you have to set the priority to C<EV::MINPRI>.
398		688
399	The process will not block as long as any idle watchers are active, and	689	The process will not block as long as any idle watchers are active, and
400	they will be called repeatedly until stopped.	690	they will be called repeatedly until stopped.
401		691
		692	For example, if you have idle watchers at priority C<0> and C<1>, and
		693	an I/O watcher at priority C<0>, then the idle watcher at priority C<1>
		694	and the I/O watcher will always run when ready. Only when the idle watcher
		695	at priority C<1> is stopped and the I/O watcher at priority C<0> is not
		696	pending with the C<0>-priority idle watcher be invoked.
		697
402	The C<idle_ns> variant doesn't start (activate) the newly created watcher.	698	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
403		699
		700	=back
		701
		702
		703	=head3 PREPARE WATCHERS - customise your event loop!
		704
		705	=over 4
404		706
405	=item $w = EV::prepare $callback	707	=item $w = EV::prepare $callback
406		708
407	=item $w = EV::prepare_ns $callback	709	=item $w = EV::prepare_ns $callback
408		710
…		…
411		713
412	See the EV::check watcher, below, for explanations and an example.	714	See the EV::check watcher, below, for explanations and an example.
413		715
414	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.	716	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
415		717
		718	=back
		719
		720
		721	=head3 CHECK WATCHERS - customise your event loop even more!
		722
		723	=over 4
416		724
417	=item $w = EV::check $callback	725	=item $w = EV::check $callback
418		726
419	=item $w = EV::check_ns $callback	727	=item $w = EV::check_ns $callback
420		728
…		…
432	# do nothing unless active	740	# do nothing unless active
433	$dispatcher->{_event_queue_h}	741	$dispatcher->{_event_queue_h}
434	or return;	742	or return;
435		743
436	# make the dispatcher handle any outstanding stuff	744	# make the dispatcher handle any outstanding stuff
		745	... not shown
437		746
438	# create an IO watcher for each and every socket	747	# create an I/O watcher for each and every socket
439	@snmp_watcher = (	748	@snmp_watcher = (
440	(map { EV::io $_, EV::READ, sub { } }	749	(map { EV::io $_, EV::READ, sub { } }
441	keys %{ $dispatcher->{_descriptors} }),	750	keys %{ $dispatcher->{_descriptors} }),
		751
		752	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		753	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		754	0, sub { },
442	);	755	);
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	};	756	};
448		757
449	The callbacks are irrelevant, the only purpose of those watchers is	758	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	759	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	760	one of those events occurs (socket readable, or timer timed out). The
452	clean up:	761	corresponding EV::check watcher will then clean up:
453		762
454	our $snmp_check = EV::check sub {	763	our $snmp_check = EV::check sub {
455	# destroy all watchers	764	# destroy all watchers
456	@snmp_watcher = ();	765	@snmp_watcher = ();
457		766
458	# make the dispatcher handle any new stuff	767	# make the dispatcher handle any new stuff
		768	... not shown
459	};	769	};
460		770
461	The callbacks of the created watchers will not be called as the watchers	771	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	772	are destroyed before this cna happen (remember EV::check gets called
463	first).	773	first).
464		774
465	The C<check_ns> variant doesn't start (activate) the newly created watcher.	775	The C<check_ns> variant doesn't start (activate) the newly created watcher.
466		776
467	=back	777	=back
468		778
		779
		780	=head3 FORK WATCHERS - the audacity to resume the event loop after a fork
		781
		782	Fork watchers are called when a C<fork ()> was detected. The invocation
		783	is done before the event loop blocks next and before C<check> watchers
		784	are being called, and only in the child after the fork.
		785
		786	=over 4
		787
		788	=item $w = EV::fork $callback
		789
		790	=item $w = EV::fork_ns $callback
		791
		792	Call the callback before the event loop is resumed in the child process
		793	after a fork.
		794
		795	The C<fork_ns> variant doesn't start (activate) the newly created watcher.
		796
		797	=back
		798
		799
		800	=head1 PERL SIGNALS
		801
		802	While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour
		803	with EV is as the same as any other C library: Perl-signals will only be
		804	handled when Perl runs, which means your signal handler might be invoked
		805	only the next time an event callback is invoked.
		806
		807	The solution is to use EV signal watchers (see C<EV::signal>), which will
		808	ensure proper operations with regards to other event watchers.
		809
		810	If you cannot do this for whatever reason, you can also force a watcher
		811	to be called on every event loop iteration by installing a C<EV::check>
		812	watcher:
		813
		814	my $async_check = EV::check sub { };
		815
		816	This ensures that perl shortly gets into control for a short time, and
		817	also ensures slower overall operation.
		818
469	=head1 THREADS	819	=head1 THREADS
470		820
471	Threads are not supported by this in any way. Perl pseudo-threads is evil	821	Threads are not supported by this module in any way. Perl pseudo-threads
472	stuff and must die.	822	is evil stuff and must die. As soon as Perl gains real threads I will work
		823	on thread support for it.
		824
		825	=head1 FORK
		826
		827	Most of the "improved" event delivering mechanisms of modern operating
		828	systems have quite a few problems with fork(2) (to put it bluntly: it is
		829	not supported and usually destructive). Libev makes it possible to work
		830	around this by having a function that recreates the kernel state after
		831	fork in the child.
		832
		833	On non-win32 platforms, this module requires the pthread_atfork
		834	functionality to do this automatically for you. This function is quite
		835	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		836	negligible, because everything the function currently does is set a flag
		837	that is checked only when the event loop gets used the next time, so when
		838	you do fork but not use EV, the overhead is minimal.
		839
		840	On win32, there is no notion of fork so all this doesn't apply, of course.
473		841
474	=cut	842	=cut
475		843
476	our $DIED = sub {	844	our $DIED = sub {
477	warn "EV: error in callback (ignoring): $@";	845	warn "EV: error in callback (ignoring): $@";
478	};	846	};
479		847
480	default_loop	848	default_loop
481	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';	849	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?';
482
483	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
484		850
485	1;	851	1;
486		852
487	=head1 SEE ALSO	853	=head1 SEE ALSO
488		854
489	L<EV::DNS>, L<EV::AnyEvent>.	855	L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as
		856	event loop), L<Coro::EV> (efficient coroutines with EV).
490		857
491	=head1 AUTHOR	858	=head1 AUTHOR
492		859
493	Marc Lehmann <schmorp@schmorp.de>	860	Marc Lehmann <schmorp@schmorp.de>
494	http://home.schmorp.de/	861	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 1.72 by root, Thu Dec 20 07:12:57 2007 UTC

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Revision 1.29 by root, Tue Nov 6 17:20:42 2007 UTC vs.
Revision 1.72 by root, Thu Dec 20 07:12:57 2007 UTC