ViewVC Help

View File | Revision Log | Show Annotations | Download File

/cvs/AnyEvent/lib/AnyEvent.pm

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.90 by root, Fri Apr 25 14:24:29 2008 UTC vs.
Revision 1.166 by root, Tue Jul 8 23:10:20 2008 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - provide framework for multiple event loops
4		4
5	EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops
6		6
7	=head1 SYNOPSIS	7	=head1 SYNOPSIS
8		8
9	use AnyEvent;	9	use AnyEvent;
10		10
…		…
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	15	my $w = AnyEvent->timer (after => $seconds, cb => sub {
16	...	16	...
17	});	17	});
18		18
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	19	my $w = AnyEvent->condvar; # stores whether a condition was flagged
		20	$w->send; # wake up current and all future recv's
20	$w->wait; # enters "main loop" till $condvar gets ->broadcast	21	$w->recv; # enters "main loop" till $condvar gets ->send
21	$w->broadcast; # wake up current and all future wait's	22
		23	=head1 INTRODUCTION/TUTORIAL
		24
		25	This manpage is mainly a reference manual. If you are interested
		26	in a tutorial or some gentle introduction, have a look at the
		27	L<AnyEvent::Intro> manpage.
22		28
23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	29	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24		30
25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	31	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26	nowadays. So what is different about AnyEvent?	32	nowadays. So what is different about AnyEvent?
…		…
48	isn't itself. What's worse, all the potential users of your module are	54	isn't itself. What's worse, all the potential users of your module are
49	I<also> forced to use the same event loop you use.	55	I<also> forced to use the same event loop you use.
50		56
51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	57	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	58	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
53	with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if	59	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
54	your module uses one of those, every user of your module has to use it,	60	your module uses one of those, every user of your module has to use it,
55	too. But if your module uses AnyEvent, it works transparently with all	61	too. But if your module uses AnyEvent, it works transparently with all
56	event models it supports (including stuff like POE and IO::Async, as long	62	event models it supports (including stuff like POE and IO::Async, as long
57	as those use one of the supported event loops. It is trivial to add new	63	as those use one of the supported event loops. It is trivial to add new
58	event loops to AnyEvent, too, so it is future-proof).	64	event loops to AnyEvent, too, so it is future-proof).
59		65
60	In addition to being free of having to use I<the one and only true event	66	In addition to being free of having to use I<the one and only true event
61	model>, AnyEvent also is free of bloat and policy: with POE or similar	67	model>, AnyEvent also is free of bloat and policy: with POE or similar
62	modules, you get an enourmous amount of code and strict rules you have to	68	modules, you get an enormous amount of code and strict rules you have to
63	follow. AnyEvent, on the other hand, is lean and up to the point, by only	69	follow. AnyEvent, on the other hand, is lean and up to the point, by only
64	offering the functionality that is necessary, in as thin as a wrapper as	70	offering the functionality that is necessary, in as thin as a wrapper as
65	technically possible.	71	technically possible.
66		72
		73	Of course, AnyEvent comes with a big (and fully optional!) toolbox
		74	of useful functionality, such as an asynchronous DNS resolver, 100%
		75	non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
		76	such as Windows) and lots of real-world knowledge and workarounds for
		77	platform bugs and differences.
		78
67	Of course, if you want lots of policy (this can arguably be somewhat	79	Now, if you I<do want> lots of policy (this can arguably be somewhat
68	useful) and you want to force your users to use the one and only event	80	useful) and you want to force your users to use the one and only event
69	model, you should I<not> use this module.	81	model, you should I<not> use this module.
70
71		82
72	=head1 DESCRIPTION	83	=head1 DESCRIPTION
73		84
74	L<AnyEvent> provides an identical interface to multiple event loops. This	85	L<AnyEvent> provides an identical interface to multiple event loops. This
75	allows module authors to utilise an event loop without forcing module	86	allows module authors to utilise an event loop without forcing module
…		…
79	The interface itself is vaguely similar, but not identical to the L<Event>	90	The interface itself is vaguely similar, but not identical to the L<Event>
80	module.	91	module.
81		92
82	During the first call of any watcher-creation method, the module tries	93	During the first call of any watcher-creation method, the module tries
83	to detect the currently loaded event loop by probing whether one of the	94	to detect the currently loaded event loop by probing whether one of the
84	following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>,	95	following modules is already loaded: L<EV>,
85	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	96	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,
86	L<POE>. The first one found is used. If none are found, the module tries	97	L<POE>. The first one found is used. If none are found, the module tries
87	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	98	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl
88	adaptor should always succeed) in the order given. The first one that can	99	adaptor should always succeed) in the order given. The first one that can
89	be successfully loaded will be used. If, after this, still none could be	100	be successfully loaded will be used. If, after this, still none could be
…		…
103	starts using it, all bets are off. Maybe you should tell their authors to	114	starts using it, all bets are off. Maybe you should tell their authors to
104	use AnyEvent so their modules work together with others seamlessly...	115	use AnyEvent so their modules work together with others seamlessly...
105		116
106	The pure-perl implementation of AnyEvent is called	117	The pure-perl implementation of AnyEvent is called
107	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	118	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
108	explicitly.	119	explicitly and enjoy the high availability of that event loop :)
109		120
110	=head1 WATCHERS	121	=head1 WATCHERS
111		122
112	AnyEvent has the central concept of a I<watcher>, which is an object that	123	AnyEvent has the central concept of a I<watcher>, which is an object that
113	stores relevant data for each kind of event you are waiting for, such as	124	stores relevant data for each kind of event you are waiting for, such as
114	the callback to call, the filehandle to watch, etc.	125	the callback to call, the file handle to watch, etc.
115		126
116	These watchers are normal Perl objects with normal Perl lifetime. After	127	These watchers are normal Perl objects with normal Perl lifetime. After
117	creating a watcher it will immediately "watch" for events and invoke the	128	creating a watcher it will immediately "watch" for events and invoke the
118	callback when the event occurs (of course, only when the event model	129	callback when the event occurs (of course, only when the event model
119	is in control).	130	is in control).
…		…
127	Many watchers either are used with "recursion" (repeating timers for	138	Many watchers either are used with "recursion" (repeating timers for
128	example), or need to refer to their watcher object in other ways.	139	example), or need to refer to their watcher object in other ways.
129		140
130	An any way to achieve that is this pattern:	141	An any way to achieve that is this pattern:
131		142
132	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	143	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
133	# you can use $w here, for example to undef it	144	# you can use $w here, for example to undef it
134	undef $w;	145	undef $w;
135	});	146	});
136		147
137	Note that C<my $w; $w => combination. This is necessary because in Perl,	148	Note that C<my $w; $w => combination. This is necessary because in Perl,
138	my variables are only visible after the statement in which they are	149	my variables are only visible after the statement in which they are
139	declared.	150	declared.
140		151
141	=head2 I/O WATCHERS	152	=head2 I/O WATCHERS
142		153
143	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	154	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
144	with the following mandatory key-value pairs as arguments:	155	with the following mandatory key-value pairs as arguments:
145		156
146	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	157	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events
147	for events. C<poll> must be a string that is either C<r> or C<w>,	158	(AnyEvent might or might not keep a reference to this file handle). C<poll>
148	which creates a watcher waiting for "r"eadable or "w"ritable events,	159	must be a string that is either C<r> or C<w>, which creates a watcher
149	respectively. C<cb> is the callback to invoke each time the file handle	160	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the
150	becomes ready.	161	callback to invoke each time the file handle becomes ready.
151		162
152	Although the callback might get passed parameters, their value and	163	Although the callback might get passed parameters, their value and
153	presence is undefined and you cannot rely on them. Portable AnyEvent	164	presence is undefined and you cannot rely on them. Portable AnyEvent
154	callbacks cannot use arguments passed to I/O watcher callbacks.	165	callbacks cannot use arguments passed to I/O watcher callbacks.
155		166
…		…
159		170
160	Some event loops issue spurious readyness notifications, so you should	171	Some event loops issue spurious readyness notifications, so you should
161	always use non-blocking calls when reading/writing from/to your file	172	always use non-blocking calls when reading/writing from/to your file
162	handles.	173	handles.
163		174
164	Example:
165
166	# wait for readability of STDIN, then read a line and disable the watcher	175	Example: wait for readability of STDIN, then read a line and disable the
		176	watcher.
		177
167	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	178	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
168	chomp (my $input = <STDIN>);	179	chomp (my $input = <STDIN>);
169	warn "read: $input\n";	180	warn "read: $input\n";
170	undef $w;	181	undef $w;
171	});	182	});
…		…
181		192
182	Although the callback might get passed parameters, their value and	193	Although the callback might get passed parameters, their value and
183	presence is undefined and you cannot rely on them. Portable AnyEvent	194	presence is undefined and you cannot rely on them. Portable AnyEvent
184	callbacks cannot use arguments passed to time watcher callbacks.	195	callbacks cannot use arguments passed to time watcher callbacks.
185		196
186	The timer callback will be invoked at most once: if you want a repeating	197	The callback will normally be invoked once only. If you specify another
187	timer you have to create a new watcher (this is a limitation by both Tk	198	parameter, C<interval>, as a strictly positive number (> 0), then the
188	and Glib).	199	callback will be invoked regularly at that interval (in fractional
		200	seconds) after the first invocation. If C<interval> is specified with a
		201	false value, then it is treated as if it were missing.
189		202
190	Example:	203	The callback will be rescheduled before invoking the callback, but no
		204	attempt is done to avoid timer drift in most backends, so the interval is
		205	only approximate.
191		206
192	# fire an event after 7.7 seconds	207	Example: fire an event after 7.7 seconds.
		208
193	my $w = AnyEvent->timer (after => 7.7, cb => sub {	209	my $w = AnyEvent->timer (after => 7.7, cb => sub {
194	warn "timeout\n";	210	warn "timeout\n";
195	});	211	});
196		212
197	# to cancel the timer:	213	# to cancel the timer:
198	undef $w;	214	undef $w;
199		215
200	Example 2:
201
202	# fire an event after 0.5 seconds, then roughly every second	216	Example 2: fire an event after 0.5 seconds, then roughly every second.
203	my $w;
204		217
205	my $cb = sub {
206	# cancel the old timer while creating a new one
207	$w = AnyEvent->timer (after => 1, cb => $cb);	218	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		219	warn "timeout\n";
208	};	220	};
209
210	# start the "loop" by creating the first watcher
211	$w = AnyEvent->timer (after => 0.5, cb => $cb);
212		221
213	=head3 TIMING ISSUES	222	=head3 TIMING ISSUES
214		223
215	There are two ways to handle timers: based on real time (relative, "fire	224	There are two ways to handle timers: based on real time (relative, "fire
216	in 10 seconds") and based on wallclock time (absolute, "fire at 12	225	in 10 seconds") and based on wallclock time (absolute, "fire at 12
…		…
228	timers.	237	timers.
229		238
230	AnyEvent always prefers relative timers, if available, matching the	239	AnyEvent always prefers relative timers, if available, matching the
231	AnyEvent API.	240	AnyEvent API.
232		241
		242	AnyEvent has two additional methods that return the "current time":
		243
		244	=over 4
		245
		246	=item AnyEvent->time
		247
		248	This returns the "current wallclock time" as a fractional number of
		249	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
		250	return, and the result is guaranteed to be compatible with those).
		251
		252	It progresses independently of any event loop processing, i.e. each call
		253	will check the system clock, which usually gets updated frequently.
		254
		255	=item AnyEvent->now
		256
		257	This also returns the "current wallclock time", but unlike C<time>, above,
		258	this value might change only once per event loop iteration, depending on
		259	the event loop (most return the same time as C<time>, above). This is the
		260	time that AnyEvent's timers get scheduled against.
		261
		262	I<In almost all cases (in all cases if you don't care), this is the
		263	function to call when you want to know the current time.>
		264
		265	This function is also often faster then C<< AnyEvent->time >>, and
		266	thus the preferred method if you want some timestamp (for example,
		267	L<AnyEvent::Handle> uses this to update it's activity timeouts).
		268
		269	The rest of this section is only of relevance if you try to be very exact
		270	with your timing, you can skip it without bad conscience.
		271
		272	For a practical example of when these times differ, consider L<Event::Lib>
		273	and L<EV> and the following set-up:
		274
		275	The event loop is running and has just invoked one of your callback at
		276	time=500 (assume no other callbacks delay processing). In your callback,
		277	you wait a second by executing C<sleep 1> (blocking the process for a
		278	second) and then (at time=501) you create a relative timer that fires
		279	after three seconds.
		280
		281	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
		282	both return C<501>, because that is the current time, and the timer will
		283	be scheduled to fire at time=504 (C<501> + C<3>).
		284
		285	With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
		286	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
		287	last event processing phase started. With L<EV>, your timer gets scheduled
		288	to run at time=503 (C<500> + C<3>).
		289
		290	In one sense, L<Event::Lib> is more exact, as it uses the current time
		291	regardless of any delays introduced by event processing. However, most
		292	callbacks do not expect large delays in processing, so this causes a
		293	higher drift (and a lot more system calls to get the current time).
		294
		295	In another sense, L<EV> is more exact, as your timer will be scheduled at
		296	the same time, regardless of how long event processing actually took.
		297
		298	In either case, if you care (and in most cases, you don't), then you
		299	can get whatever behaviour you want with any event loop, by taking the
		300	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
		301	account.
		302
		303	=back
		304
233	=head2 SIGNAL WATCHERS	305	=head2 SIGNAL WATCHERS
234		306
235	You can watch for signals using a signal watcher, C<signal> is the signal	307	You can watch for signals using a signal watcher, C<signal> is the signal
236	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to	308	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to
237	be invoked whenever a signal occurs.	309	be invoked whenever a signal occurs.
238		310
239	Although the callback might get passed parameters, their value and	311	Although the callback might get passed parameters, their value and
240	presence is undefined and you cannot rely on them. Portable AnyEvent	312	presence is undefined and you cannot rely on them. Portable AnyEvent
241	callbacks cannot use arguments passed to signal watcher callbacks.	313	callbacks cannot use arguments passed to signal watcher callbacks.
242		314
243	Multiple signal occurances can be clumped together into one callback	315	Multiple signal occurrences can be clumped together into one callback
244	invocation, and callback invocation will be synchronous. synchronous means	316	invocation, and callback invocation will be synchronous. Synchronous means
245	that it might take a while until the signal gets handled by the process,	317	that it might take a while until the signal gets handled by the process,
246	but it is guarenteed not to interrupt any other callbacks.	318	but it is guaranteed not to interrupt any other callbacks.
247		319
248	The main advantage of using these watchers is that you can share a signal	320	The main advantage of using these watchers is that you can share a signal
249	between multiple watchers.	321	between multiple watchers.
250		322
251	This watcher might use C<%SIG>, so programs overwriting those signals	323	This watcher might use C<%SIG>, so programs overwriting those signals
…		…
278	AnyEvent program, you I<have> to create at least one watcher before you	350	AnyEvent program, you I<have> to create at least one watcher before you
279	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	351	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
280		352
281	Example: fork a process and wait for it	353	Example: fork a process and wait for it
282		354
283	my $done = AnyEvent->condvar;	355	my $done = AnyEvent->condvar;
284		356
285	AnyEvent::detect; # force event module to be initialised
286
287	my $pid = fork or exit 5;	357	my $pid = fork or exit 5;
288		358
289	my $w = AnyEvent->child (	359	my $w = AnyEvent->child (
290	pid => $pid,	360	pid => $pid,
291	cb => sub {	361	cb => sub {
292	my ($pid, $status) = @_;	362	my ($pid, $status) = @_;
293	warn "pid $pid exited with status $status";	363	warn "pid $pid exited with status $status";
294	$done->broadcast;	364	$done->send;
295	},	365	},
296	);	366	);
297		367
298	# do something else, then wait for process exit	368	# do something else, then wait for process exit
299	$done->wait;	369	$done->recv;
300		370
301	=head2 CONDITION VARIABLES	371	=head2 CONDITION VARIABLES
302		372
		373	If you are familiar with some event loops you will know that all of them
		374	require you to run some blocking "loop", "run" or similar function that
		375	will actively watch for new events and call your callbacks.
		376
		377	AnyEvent is different, it expects somebody else to run the event loop and
		378	will only block when necessary (usually when told by the user).
		379
		380	The instrument to do that is called a "condition variable", so called
		381	because they represent a condition that must become true.
		382
303	Condition variables can be created by calling the C<< AnyEvent->condvar >>	383	Condition variables can be created by calling the C<< AnyEvent->condvar
304	method without any arguments.	384	>> method, usually without arguments. The only argument pair allowed is
		385	C<cb>, which specifies a callback to be called when the condition variable
		386	becomes true.
305		387
306	A condition variable waits for a condition - precisely that the C<<	388	After creation, the condition variable is "false" until it becomes "true"
307	->broadcast >> method has been called.	389	by calling the C<send> method (or calling the condition variable as if it
		390	were a callback, read about the caveats in the description for the C<<
		391	->send >> method).
308		392
309	They are very useful to signal that a condition has been fulfilled, for	393	Condition variables are similar to callbacks, except that you can
		394	optionally wait for them. They can also be called merge points - points
		395	in time where multiple outstanding events have been processed. And yet
		396	another way to call them is transactions - each condition variable can be
		397	used to represent a transaction, which finishes at some point and delivers
		398	a result.
		399
		400	Condition variables are very useful to signal that something has finished,
310	example, if you write a module that does asynchronous http requests,	401	for example, if you write a module that does asynchronous http requests,
311	then a condition variable would be the ideal candidate to signal the	402	then a condition variable would be the ideal candidate to signal the
312	availability of results.	403	availability of results. The user can either act when the callback is
		404	called or can synchronously C<< ->recv >> for the results.
313		405
314	You can also use condition variables to block your main program until	406	You can also use them to simulate traditional event loops - for example,
315	an event occurs - for example, you could C<< ->wait >> in your main	407	you can block your main program until an event occurs - for example, you
316	program until the user clicks the Quit button in your app, which would C<<	408	could C<< ->recv >> in your main program until the user clicks the Quit
317	->broadcast >> the "quit" event.	409	button of your app, which would C<< ->send >> the "quit" event.
318		410
319	Note that condition variables recurse into the event loop - if you have	411	Note that condition variables recurse into the event loop - if you have
320	two pirces of code that call C<< ->wait >> in a round-robbin fashion, you	412	two pieces of code that call C<< ->recv >> in a round-robin fashion, you
321	lose. Therefore, condition variables are good to export to your caller, but	413	lose. Therefore, condition variables are good to export to your caller, but
322	you should avoid making a blocking wait yourself, at least in callbacks,	414	you should avoid making a blocking wait yourself, at least in callbacks,
323	as this asks for trouble.	415	as this asks for trouble.
324		416
325	This object has two methods:	417	Condition variables are represented by hash refs in perl, and the keys
		418	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
		419	easy (it is often useful to build your own transaction class on top of
		420	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
		421	it's C<new> method in your own C<new> method.
		422
		423	There are two "sides" to a condition variable - the "producer side" which
		424	eventually calls C<< -> send >>, and the "consumer side", which waits
		425	for the send to occur.
		426
		427	Example: wait for a timer.
		428
		429	# wait till the result is ready
		430	my $result_ready = AnyEvent->condvar;
		431
		432	# do something such as adding a timer
		433	# or socket watcher the calls $result_ready->send
		434	# when the "result" is ready.
		435	# in this case, we simply use a timer:
		436	my $w = AnyEvent->timer (
		437	after => 1,
		438	cb => sub { $result_ready->send },
		439	);
		440
		441	# this "blocks" (while handling events) till the callback
		442	# calls send
		443	$result_ready->recv;
		444
		445	Example: wait for a timer, but take advantage of the fact that
		446	condition variables are also code references.
		447
		448	my $done = AnyEvent->condvar;
		449	my $delay = AnyEvent->timer (after => 5, cb => $done);
		450	$done->recv;
		451
		452	=head3 METHODS FOR PRODUCERS
		453
		454	These methods should only be used by the producing side, i.e. the
		455	code/module that eventually sends the signal. Note that it is also
		456	the producer side which creates the condvar in most cases, but it isn't
		457	uncommon for the consumer to create it as well.
326		458
327	=over 4	459	=over 4
328		460
		461	=item $cv->send (...)
		462
		463	Flag the condition as ready - a running C<< ->recv >> and all further
		464	calls to C<recv> will (eventually) return after this method has been
		465	called. If nobody is waiting the send will be remembered.
		466
		467	If a callback has been set on the condition variable, it is called
		468	immediately from within send.
		469
		470	Any arguments passed to the C<send> call will be returned by all
		471	future C<< ->recv >> calls.
		472
		473	Condition variables are overloaded so one can call them directly
		474	(as a code reference). Calling them directly is the same as calling
		475	C<send>. Note, however, that many C-based event loops do not handle
		476	overloading, so as tempting as it may be, passing a condition variable
		477	instead of a callback does not work. Both the pure perl and EV loops
		478	support overloading, however, as well as all functions that use perl to
		479	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
		480	example).
		481
		482	=item $cv->croak ($error)
		483
		484	Similar to send, but causes all call's to C<< ->recv >> to invoke
		485	C<Carp::croak> with the given error message/object/scalar.
		486
		487	This can be used to signal any errors to the condition variable
		488	user/consumer.
		489
		490	=item $cv->begin ([group callback])
		491
329	=item $cv->wait	492	=item $cv->end
330		493
331	Wait (blocking if necessary) until the C<< ->broadcast >> method has been	494	These two methods are EXPERIMENTAL and MIGHT CHANGE.
		495
		496	These two methods can be used to combine many transactions/events into
		497	one. For example, a function that pings many hosts in parallel might want
		498	to use a condition variable for the whole process.
		499
		500	Every call to C<< ->begin >> will increment a counter, and every call to
		501	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
		502	>>, the (last) callback passed to C<begin> will be executed. That callback
		503	is I<supposed> to call C<< ->send >>, but that is not required. If no
		504	callback was set, C<send> will be called without any arguments.
		505
		506	Let's clarify this with the ping example:
		507
		508	my $cv = AnyEvent->condvar;
		509
		510	my %result;
		511	$cv->begin (sub { $cv->send (\%result) });
		512
		513	for my $host (@list_of_hosts) {
		514	$cv->begin;
		515	ping_host_then_call_callback $host, sub {
		516	$result{$host} = ...;
		517	$cv->end;
		518	};
		519	}
		520
		521	$cv->end;
		522
		523	This code fragment supposedly pings a number of hosts and calls
		524	C<send> after results for all then have have been gathered - in any
		525	order. To achieve this, the code issues a call to C<begin> when it starts
		526	each ping request and calls C<end> when it has received some result for
		527	it. Since C<begin> and C<end> only maintain a counter, the order in which
		528	results arrive is not relevant.
		529
		530	There is an additional bracketing call to C<begin> and C<end> outside the
		531	loop, which serves two important purposes: first, it sets the callback
		532	to be called once the counter reaches C<0>, and second, it ensures that
		533	C<send> is called even when C<no> hosts are being pinged (the loop
		534	doesn't execute once).
		535
		536	This is the general pattern when you "fan out" into multiple subrequests:
		537	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>
		538	is called at least once, and then, for each subrequest you start, call
		539	C<begin> and for each subrequest you finish, call C<end>.
		540
		541	=back
		542
		543	=head3 METHODS FOR CONSUMERS
		544
		545	These methods should only be used by the consuming side, i.e. the
		546	code awaits the condition.
		547
		548	=over 4
		549
		550	=item $cv->recv
		551
		552	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
332	called on c<$cv>, while servicing other watchers normally.	553	>> methods have been called on c<$cv>, while servicing other watchers
		554	normally.
333		555
334	You can only wait once on a condition - additional calls will return	556	You can only wait once on a condition - additional calls are valid but
335	immediately.	557	will return immediately.
		558
		559	If an error condition has been set by calling C<< ->croak >>, then this
		560	function will call C<croak>.
		561
		562	In list context, all parameters passed to C<send> will be returned,
		563	in scalar context only the first one will be returned.
336		564
337	Not all event models support a blocking wait - some die in that case	565	Not all event models support a blocking wait - some die in that case
338	(programs might want to do that to stay interactive), so I<if you are	566	(programs might want to do that to stay interactive), so I<if you are
339	using this from a module, never require a blocking wait>, but let the	567	using this from a module, never require a blocking wait>, but let the
340	caller decide whether the call will block or not (for example, by coupling	568	caller decide whether the call will block or not (for example, by coupling
341	condition variables with some kind of request results and supporting	569	condition variables with some kind of request results and supporting
342	callbacks so the caller knows that getting the result will not block,	570	callbacks so the caller knows that getting the result will not block,
343	while still suppporting blocking waits if the caller so desires).	571	while still supporting blocking waits if the caller so desires).
344		572
345	Another reason I<never> to C<< ->wait >> in a module is that you cannot	573	Another reason I<never> to C<< ->recv >> in a module is that you cannot
346	sensibly have two C<< ->wait >>'s in parallel, as that would require	574	sensibly have two C<< ->recv >>'s in parallel, as that would require
347	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	575	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
348	can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and	576	can supply.
349	L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
350	from different coroutines, however).
351		577
352	=item $cv->broadcast	578	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
		579	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
		580	versions and also integrates coroutines into AnyEvent, making blocking
		581	C<< ->recv >> calls perfectly safe as long as they are done from another
		582	coroutine (one that doesn't run the event loop).
353		583
354	Flag the condition as ready - a running C<< ->wait >> and all further	584	You can ensure that C<< -recv >> never blocks by setting a callback and
355	calls to C<wait> will (eventually) return after this method has been	585	only calling C<< ->recv >> from within that callback (or at a later
356	called. If nobody is waiting the broadcast will be remembered..	586	time). This will work even when the event loop does not support blocking
		587	waits otherwise.
		588
		589	=item $bool = $cv->ready
		590
		591	Returns true when the condition is "true", i.e. whether C<send> or
		592	C<croak> have been called.
		593
		594	=item $cb = $cv->cb ([new callback])
		595
		596	This is a mutator function that returns the callback set and optionally
		597	replaces it before doing so.
		598
		599	The callback will be called when the condition becomes "true", i.e. when
		600	C<send> or C<croak> are called, with the only argument being the condition
		601	variable itself. Calling C<recv> inside the callback or at any later time
		602	is guaranteed not to block.
357		603
358	=back	604	=back
359
360	Example:
361
362	# wait till the result is ready
363	my $result_ready = AnyEvent->condvar;
364
365	# do something such as adding a timer
366	# or socket watcher the calls $result_ready->broadcast
367	# when the "result" is ready.
368	# in this case, we simply use a timer:
369	my $w = AnyEvent->timer (
370	after => 1,
371	cb => sub { $result_ready->broadcast },
372	);
373
374	# this "blocks" (while handling events) till the watcher
375	# calls broadcast
376	$result_ready->wait;
377		605
378	=head1 GLOBAL VARIABLES AND FUNCTIONS	606	=head1 GLOBAL VARIABLES AND FUNCTIONS
379		607
380	=over 4	608	=over 4
381		609
…		…
387	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	615	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
388	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	616	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
389		617
390	The known classes so far are:	618	The known classes so far are:
391		619
392	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
393	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
394	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).	620	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
395	AnyEvent::Impl::Event based on Event, second best choice.	621	AnyEvent::Impl::Event based on Event, second best choice.
		622	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
396	AnyEvent::Impl::Glib based on Glib, third-best choice.	623	AnyEvent::Impl::Glib based on Glib, third-best choice.
397	AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable.
398	AnyEvent::Impl::Tk based on Tk, very bad choice.	624	AnyEvent::Impl::Tk based on Tk, very bad choice.
399	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).	625	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
400	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	626	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
401	AnyEvent::Impl::POE based on POE, not generic enough for full support.	627	AnyEvent::Impl::POE based on POE, not generic enough for full support.
402		628
…		…
415	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	641	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
416	if necessary. You should only call this function right before you would	642	if necessary. You should only call this function right before you would
417	have created an AnyEvent watcher anyway, that is, as late as possible at	643	have created an AnyEvent watcher anyway, that is, as late as possible at
418	runtime.	644	runtime.
419		645
		646	=item $guard = AnyEvent::post_detect { BLOCK }
		647
		648	Arranges for the code block to be executed as soon as the event model is
		649	autodetected (or immediately if this has already happened).
		650
		651	If called in scalar or list context, then it creates and returns an object
		652	that automatically removes the callback again when it is destroyed. See
		653	L<Coro::BDB> for a case where this is useful.
		654
		655	=item @AnyEvent::post_detect
		656
		657	If there are any code references in this array (you can C<push> to it
		658	before or after loading AnyEvent), then they will called directly after
		659	the event loop has been chosen.
		660
		661	You should check C<$AnyEvent::MODEL> before adding to this array, though:
		662	if it contains a true value then the event loop has already been detected,
		663	and the array will be ignored.
		664
		665	Best use C<AnyEvent::post_detect { BLOCK }> instead.
		666
420	=back	667	=back
421		668
422	=head1 WHAT TO DO IN A MODULE	669	=head1 WHAT TO DO IN A MODULE
423		670
424	As a module author, you should C<use AnyEvent> and call AnyEvent methods	671	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
427	Be careful when you create watchers in the module body - AnyEvent will	674	Be careful when you create watchers in the module body - AnyEvent will
428	decide which event module to use as soon as the first method is called, so	675	decide which event module to use as soon as the first method is called, so
429	by calling AnyEvent in your module body you force the user of your module	676	by calling AnyEvent in your module body you force the user of your module
430	to load the event module first.	677	to load the event module first.
431		678
432	Never call C<< ->wait >> on a condition variable unless you I<know> that	679	Never call C<< ->recv >> on a condition variable unless you I<know> that
433	the C<< ->broadcast >> method has been called on it already. This is	680	the C<< ->send >> method has been called on it already. This is
434	because it will stall the whole program, and the whole point of using	681	because it will stall the whole program, and the whole point of using
435	events is to stay interactive.	682	events is to stay interactive.
436		683
437	It is fine, however, to call C<< ->wait >> when the user of your module	684	It is fine, however, to call C<< ->recv >> when the user of your module
438	requests it (i.e. if you create a http request object ad have a method	685	requests it (i.e. if you create a http request object ad have a method
439	called C<results> that returns the results, it should call C<< ->wait >>	686	called C<results> that returns the results, it should call C<< ->recv >>
440	freely, as the user of your module knows what she is doing. always).	687	freely, as the user of your module knows what she is doing. always).
441		688
442	=head1 WHAT TO DO IN THE MAIN PROGRAM	689	=head1 WHAT TO DO IN THE MAIN PROGRAM
443		690
444	There will always be a single main program - the only place that should	691	There will always be a single main program - the only place that should
…		…
446		693
447	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	694	If it doesn't care, it can just "use AnyEvent" and use it itself, or not
448	do anything special (it does not need to be event-based) and let AnyEvent	695	do anything special (it does not need to be event-based) and let AnyEvent
449	decide which implementation to chose if some module relies on it.	696	decide which implementation to chose if some module relies on it.
450		697
451	If the main program relies on a specific event model. For example, in	698	If the main program relies on a specific event model - for example, in
452	Gtk2 programs you have to rely on the Glib module. You should load the	699	Gtk2 programs you have to rely on the Glib module - you should load the
453	event module before loading AnyEvent or any module that uses it: generally	700	event module before loading AnyEvent or any module that uses it: generally
454	speaking, you should load it as early as possible. The reason is that	701	speaking, you should load it as early as possible. The reason is that
455	modules might create watchers when they are loaded, and AnyEvent will	702	modules might create watchers when they are loaded, and AnyEvent will
456	decide on the event model to use as soon as it creates watchers, and it	703	decide on the event model to use as soon as it creates watchers, and it
457	might chose the wrong one unless you load the correct one yourself.	704	might chose the wrong one unless you load the correct one yourself.
458		705
459	You can chose to use a rather inefficient pure-perl implementation by	706	You can chose to use a pure-perl implementation by loading the
460	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	707	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
461	behaviour everywhere, but letting AnyEvent chose is generally better.	708	everywhere, but letting AnyEvent chose the model is generally better.
		709
		710	=head2 MAINLOOP EMULATION
		711
		712	Sometimes (often for short test scripts, or even standalone programs who
		713	only want to use AnyEvent), you do not want to run a specific event loop.
		714
		715	In that case, you can use a condition variable like this:
		716
		717	AnyEvent->condvar->recv;
		718
		719	This has the effect of entering the event loop and looping forever.
		720
		721	Note that usually your program has some exit condition, in which case
		722	it is better to use the "traditional" approach of storing a condition
		723	variable somewhere, waiting for it, and sending it when the program should
		724	exit cleanly.
		725
		726
		727	=head1 OTHER MODULES
		728
		729	The following is a non-exhaustive list of additional modules that use
		730	AnyEvent and can therefore be mixed easily with other AnyEvent modules
		731	in the same program. Some of the modules come with AnyEvent, some are
		732	available via CPAN.
		733
		734	=over 4
		735
		736	=item L<AnyEvent::Util>
		737
		738	Contains various utility functions that replace often-used but blocking
		739	functions such as C<inet_aton> by event-/callback-based versions.
		740
		741	=item L<AnyEvent::Socket>
		742
		743	Provides various utility functions for (internet protocol) sockets,
		744	addresses and name resolution. Also functions to create non-blocking tcp
		745	connections or tcp servers, with IPv6 and SRV record support and more.
		746
		747	=item L<AnyEvent::Handle>
		748
		749	Provide read and write buffers, manages watchers for reads and writes,
		750	supports raw and formatted I/O, I/O queued and fully transparent and
		751	non-blocking SSL/TLS.
		752
		753	=item L<AnyEvent::DNS>
		754
		755	Provides rich asynchronous DNS resolver capabilities.
		756
		757	=item L<AnyEvent::HTTP>
		758
		759	A simple-to-use HTTP library that is capable of making a lot of concurrent
		760	HTTP requests.
		761
		762	=item L<AnyEvent::HTTPD>
		763
		764	Provides a simple web application server framework.
		765
		766	=item L<AnyEvent::FastPing>
		767
		768	The fastest ping in the west.
		769
		770	=item L<AnyEvent::DBI>
		771
		772	Executes L<DBI> requests asynchronously in a proxy process.
		773
		774	=item L<AnyEvent::AIO>
		775
		776	Truly asynchronous I/O, should be in the toolbox of every event
		777	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		778	together.
		779
		780	=item L<AnyEvent::BDB>
		781
		782	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		783	L<BDB> and AnyEvent together.
		784
		785	=item L<AnyEvent::GPSD>
		786
		787	A non-blocking interface to gpsd, a daemon delivering GPS information.
		788
		789	=item L<AnyEvent::IGS>
		790
		791	A non-blocking interface to the Internet Go Server protocol (used by
		792	L<App::IGS>).
		793
		794	=item L<Net::IRC3>
		795
		796	AnyEvent based IRC client module family.
		797
		798	=item L<Net::XMPP2>
		799
		800	AnyEvent based XMPP (Jabber protocol) module family.
		801
		802	=item L<Net::FCP>
		803
		804	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
		805	of AnyEvent.
		806
		807	=item L<Event::ExecFlow>
		808
		809	High level API for event-based execution flow control.
		810
		811	=item L<Coro>
		812
		813	Has special support for AnyEvent via L<Coro::AnyEvent>.
		814
		815	=item L<IO::Lambda>
		816
		817	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
		818
		819	=back
462		820
463	=cut	821	=cut
464		822
465	package AnyEvent;	823	package AnyEvent;
466		824
467	no warnings;	825	no warnings;
468	use strict;	826	use strict;
469		827
470	use Carp;	828	use Carp;
471		829
472	our $VERSION = '3.3';	830	our $VERSION = 4.2;
473	our $MODEL;	831	our $MODEL;
474		832
475	our $AUTOLOAD;	833	our $AUTOLOAD;
476	our @ISA;	834	our @ISA;
477		835
		836	our @REGISTRY;
		837
		838	our $WIN32;
		839
		840	BEGIN {
		841	my $win32 = ! ! ($^O =~ /mswin32/i);
		842	eval "sub WIN32(){ $win32 }";
		843	}
		844
478	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	845	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
479		846
480	our @REGISTRY;	847	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
		848
		849	{
		850	my $idx;
		851	$PROTOCOL{$_} = ++$idx
		852	for reverse split /\s*,\s*/,
		853	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
		854	}
481		855
482	my @models = (	856	my @models = (
483	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
484	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
485	[EV:: => AnyEvent::Impl::EV::],	857	[EV:: => AnyEvent::Impl::EV::],
486	[Event:: => AnyEvent::Impl::Event::],	858	[Event:: => AnyEvent::Impl::Event::],
487	[Glib:: => AnyEvent::Impl::Glib::],
488	[Tk:: => AnyEvent::Impl::Tk::],
489	[Wx:: => AnyEvent::Impl::POE::],
490	[Prima:: => AnyEvent::Impl::POE::],
491	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	859	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
492	# everything below here will not be autoprobed as the pureperl backend should work everywhere	860	# everything below here will not be autoprobed
		861	# as the pureperl backend should work everywhere
		862	# and is usually faster
		863	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		864	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
493	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	865	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
494	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	866	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
495	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	867	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
		868	[Wx:: => AnyEvent::Impl::POE::],
		869	[Prima:: => AnyEvent::Impl::POE::],
496	);	870	);
497		871
498	our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY);	872	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
		873
		874	our @post_detect;
		875
		876	sub post_detect(&) {
		877	my ($cb) = @_;
		878
		879	if ($MODEL) {
		880	$cb->();
		881
		882	1
		883	} else {
		884	push @post_detect, $cb;
		885
		886	defined wantarray
		887	? bless \$cb, "AnyEvent::Util::PostDetect"
		888	: ()
		889	}
		890	}
		891
		892	sub AnyEvent::Util::PostDetect::DESTROY {
		893	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		894	}
499		895
500	sub detect() {	896	sub detect() {
501	unless ($MODEL) {	897	unless ($MODEL) {
502	no strict 'refs';	898	no strict 'refs';
		899	local $SIG{__DIE__};
503		900
504	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	901	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
505	my $model = "AnyEvent::Impl::$1";	902	my $model = "AnyEvent::Impl::$1";
506	if (eval "require $model") {	903	if (eval "require $model") {
507	$MODEL = $model;	904	$MODEL = $model;
…		…
537	last;	934	last;
538	}	935	}
539	}	936	}
540		937
541	$MODEL	938	$MODEL
542	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib.";	939	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
543	}	940	}
544	}	941	}
545		942
546	unshift @ISA, $MODEL;	943	unshift @ISA, $MODEL;
547	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	944	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		945
		946	(shift @post_detect)->() while @post_detect;
548	}	947	}
549		948
550	$MODEL	949	$MODEL
551	}	950	}
552		951
…		…
562	$class->$func (@_);	961	$class->$func (@_);
563	}	962	}
564		963
565	package AnyEvent::Base;	964	package AnyEvent::Base;
566		965
		966	# default implementation for now and time
		967
		968	use Time::HiRes ();
		969
		970	sub time { Time::HiRes::time }
		971	sub now { Time::HiRes::time }
		972
567	# default implementation for ->condvar, ->wait, ->broadcast	973	# default implementation for ->condvar
568		974
569	sub condvar {	975	sub condvar {
570	bless \my $flag, "AnyEvent::Base::CondVar"	976	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
571	}
572
573	sub AnyEvent::Base::CondVar::broadcast {
574	${$_[0]}++;
575	}
576
577	sub AnyEvent::Base::CondVar::wait {
578	AnyEvent->one_event while !${$_[0]};
579	}	977	}
580		978
581	# default implementation for ->signal	979	# default implementation for ->signal
582		980
583	our %SIG_CB;	981	our %SIG_CB;
…		…
599	sub AnyEvent::Base::Signal::DESTROY {	997	sub AnyEvent::Base::Signal::DESTROY {
600	my ($signal, $cb) = @{$_[0]};	998	my ($signal, $cb) = @{$_[0]};
601		999
602	delete $SIG_CB{$signal}{$cb};	1000	delete $SIG_CB{$signal}{$cb};
603		1001
604	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1002	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
605	}	1003	}
606		1004
607	# default implementation for ->child	1005	# default implementation for ->child
608		1006
609	our %PID_CB;	1007	our %PID_CB;
…		…
636	or Carp::croak "required option 'pid' is missing";	1034	or Carp::croak "required option 'pid' is missing";
637		1035
638	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1036	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
639		1037
640	unless ($WNOHANG) {	1038	unless ($WNOHANG) {
641	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1;	1039	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
642	}	1040	}
643		1041
644	unless ($CHLD_W) {	1042	unless ($CHLD_W) {
645	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1043	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
646	# child could be a zombie already, so make at least one round	1044	# child could be a zombie already, so make at least one round
…		…
656	delete $PID_CB{$pid}{$cb};	1054	delete $PID_CB{$pid}{$cb};
657	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1055	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
658		1056
659	undef $CHLD_W unless keys %PID_CB;	1057	undef $CHLD_W unless keys %PID_CB;
660	}	1058	}
		1059
		1060	package AnyEvent::CondVar;
		1061
		1062	our @ISA = AnyEvent::CondVar::Base::;
		1063
		1064	package AnyEvent::CondVar::Base;
		1065
		1066	use overload
		1067	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		1068	fallback => 1;
		1069
		1070	sub _send {
		1071	# nop
		1072	}
		1073
		1074	sub send {
		1075	my $cv = shift;
		1076	$cv->{_ae_sent} = [@_];
		1077	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		1078	$cv->_send;
		1079	}
		1080
		1081	sub croak {
		1082	$_[0]{_ae_croak} = $_[1];
		1083	$_[0]->send;
		1084	}
		1085
		1086	sub ready {
		1087	$_[0]{_ae_sent}
		1088	}
		1089
		1090	sub _wait {
		1091	AnyEvent->one_event while !$_[0]{_ae_sent};
		1092	}
		1093
		1094	sub recv {
		1095	$_[0]->_wait;
		1096
		1097	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		1098	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		1099	}
		1100
		1101	sub cb {
		1102	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		1103	$_[0]{_ae_cb}
		1104	}
		1105
		1106	sub begin {
		1107	++$_[0]{_ae_counter};
		1108	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		1109	}
		1110
		1111	sub end {
		1112	return if --$_[0]{_ae_counter};
		1113	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
		1114	}
		1115
		1116	# undocumented/compatibility with pre-3.4
		1117	*broadcast = \&send;
		1118	*wait = \&_wait;
661		1119
662	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1120	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
663		1121
664	This is an advanced topic that you do not normally need to use AnyEvent in	1122	This is an advanced topic that you do not normally need to use AnyEvent in
665	a module. This section is only of use to event loop authors who want to	1123	a module. This section is only of use to event loop authors who want to
…		…
722	model it chooses.	1180	model it chooses.
723		1181
724	=item C<PERL_ANYEVENT_MODEL>	1182	=item C<PERL_ANYEVENT_MODEL>
725		1183
726	This can be used to specify the event model to be used by AnyEvent, before	1184	This can be used to specify the event model to be used by AnyEvent, before
727	autodetection and -probing kicks in. It must be a string consisting	1185	auto detection and -probing kicks in. It must be a string consisting
728	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1186	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
729	and the resulting module name is loaded and if the load was successful,	1187	and the resulting module name is loaded and if the load was successful,
730	used as event model. If it fails to load AnyEvent will proceed with	1188	used as event model. If it fails to load AnyEvent will proceed with
731	autodetection and -probing.	1189	auto detection and -probing.
732		1190
733	This functionality might change in future versions.	1191	This functionality might change in future versions.
734		1192
735	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1193	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
736	could start your program like this:	1194	could start your program like this:
737		1195
738	PERL_ANYEVENT_MODEL=Perl perl ...	1196	PERL_ANYEVENT_MODEL=Perl perl ...
		1197
		1198	=item C<PERL_ANYEVENT_PROTOCOLS>
		1199
		1200	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1201	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1202	of auto probing).
		1203
		1204	Must be set to a comma-separated list of protocols or address families,
		1205	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1206	used, and preference will be given to protocols mentioned earlier in the
		1207	list.
		1208
		1209	This variable can effectively be used for denial-of-service attacks
		1210	against local programs (e.g. when setuid), although the impact is likely
		1211	small, as the program has to handle connection errors already-
		1212
		1213	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1214	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1215	- only support IPv4, never try to resolve or contact IPv6
		1216	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1217	IPv6, but prefer IPv6 over IPv4.
		1218
		1219	=item C<PERL_ANYEVENT_EDNS0>
		1220
		1221	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1222	for DNS. This extension is generally useful to reduce DNS traffic, but
		1223	some (broken) firewalls drop such DNS packets, which is why it is off by
		1224	default.
		1225
		1226	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1227	EDNS0 in its DNS requests.
		1228
		1229	=item C<PERL_ANYEVENT_MAX_FORKS>
		1230
		1231	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1232	will create in parallel.
739		1233
740	=back	1234	=back
741		1235
742	=head1 EXAMPLE PROGRAM	1236	=head1 EXAMPLE PROGRAM
743		1237
…		…
754	poll => 'r',	1248	poll => 'r',
755	cb => sub {	1249	cb => sub {
756	warn "io event <$_[0]>\n"; # will always output <r>	1250	warn "io event <$_[0]>\n"; # will always output <r>
757	chomp (my $input = <STDIN>); # read a line	1251	chomp (my $input = <STDIN>); # read a line
758	warn "read: $input\n"; # output what has been read	1252	warn "read: $input\n"; # output what has been read
759	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1253	$cv->send if $input =~ /^q/i; # quit program if /^q/i
760	},	1254	},
761	);	1255	);
762		1256
763	my $time_watcher; # can only be used once	1257	my $time_watcher; # can only be used once
764		1258
…		…
769	});	1263	});
770	}	1264	}
771		1265
772	new_timer; # create first timer	1266	new_timer; # create first timer
773		1267
774	$cv->wait; # wait until user enters /^q/i	1268	$cv->recv; # wait until user enters /^q/i
775		1269
776	=head1 REAL-WORLD EXAMPLE	1270	=head1 REAL-WORLD EXAMPLE
777		1271
778	Consider the L<Net::FCP> module. It features (among others) the following	1272	Consider the L<Net::FCP> module. It features (among others) the following
779	API calls, which are to freenet what HTTP GET requests are to http:	1273	API calls, which are to freenet what HTTP GET requests are to http:
…		…
829	syswrite $txn->{fh}, $txn->{request}	1323	syswrite $txn->{fh}, $txn->{request}
830	or die "connection or write error";	1324	or die "connection or write error";
831	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1325	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
832		1326
833	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1327	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
834	result and signals any possible waiters that the request ahs finished:	1328	result and signals any possible waiters that the request has finished:
835		1329
836	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1330	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
837		1331
838	if (end-of-file or data complete) {	1332	if (end-of-file or data complete) {
839	$txn->{result} = $txn->{buf};	1333	$txn->{result} = $txn->{buf};
840	$txn->{finished}->broadcast;	1334	$txn->{finished}->send;
841	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1335	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
842	}	1336	}
843		1337
844	The C<result> method, finally, just waits for the finished signal (if the	1338	The C<result> method, finally, just waits for the finished signal (if the
845	request was already finished, it doesn't wait, of course, and returns the	1339	request was already finished, it doesn't wait, of course, and returns the
846	data:	1340	data:
847		1341
848	$txn->{finished}->wait;	1342	$txn->{finished}->recv;
849	return $txn->{result};	1343	return $txn->{result};
850		1344
851	The actual code goes further and collects all errors (C<die>s, exceptions)	1345	The actual code goes further and collects all errors (C<die>s, exceptions)
852	that occured during request processing. The C<result> method detects	1346	that occurred during request processing. The C<result> method detects
853	whether an exception as thrown (it is stored inside the $txn object)	1347	whether an exception as thrown (it is stored inside the $txn object)
854	and just throws the exception, which means connection errors and other	1348	and just throws the exception, which means connection errors and other
855	problems get reported tot he code that tries to use the result, not in a	1349	problems get reported tot he code that tries to use the result, not in a
856	random callback.	1350	random callback.
857		1351
…		…
888		1382
889	my $quit = AnyEvent->condvar;	1383	my $quit = AnyEvent->condvar;
890		1384
891	$fcp->txn_client_get ($url)->cb (sub {	1385	$fcp->txn_client_get ($url)->cb (sub {
892	...	1386	...
893	$quit->broadcast;	1387	$quit->send;
894	});	1388	});
895		1389
896	$quit->wait;	1390	$quit->recv;
897		1391
898		1392
899	=head1 BENCHMARK	1393	=head1 BENCHMARKS
900		1394
901	To give you an idea of the performance and overheads that AnyEvent adds	1395	To give you an idea of the performance and overheads that AnyEvent adds
902	over the event loops themselves (and to give you an impression of the	1396	over the event loops themselves and to give you an impression of the speed
903	speed of various event loops), here is a benchmark of various supported	1397	of various event loops I prepared some benchmarks.
904	event models natively and with anyevent. The benchmark creates a lot of	1398
905	timers (with a zero timeout) and I/O watchers (watching STDOUT, a pty, to	1399	=head2 BENCHMARKING ANYEVENT OVERHEAD
		1400
		1401	Here is a benchmark of various supported event models used natively and
		1402	through AnyEvent. The benchmark creates a lot of timers (with a zero
		1403	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
906	become writable, which it is), lets them fire exactly once and destroys	1404	which it is), lets them fire exactly once and destroys them again.
907	them again.
908		1405
909	Rewriting the benchmark to use many different sockets instead of using	1406	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
910	the same filehandle for all I/O watchers results in a much longer runtime	1407	distribution.
911	(socket creation is expensive), but qualitatively the same figures, so it
912	was not used.
913		1408
914	=head2 Explanation of the columns	1409	=head3 Explanation of the columns
915		1410
916	I<watcher> is the number of event watchers created/destroyed. Since	1411	I<watcher> is the number of event watchers created/destroyed. Since
917	different event models feature vastly different performances, each event	1412	different event models feature vastly different performances, each event
918	loop was given a number of watchers so that overall runtime is acceptable	1413	loop was given a number of watchers so that overall runtime is acceptable
919	and similar between tested event loop (and keep them from crashing): Glib	1414	and similar between tested event loop (and keep them from crashing): Glib
…		…
929	all watchers, to avoid adding memory overhead. That means closure creation	1424	all watchers, to avoid adding memory overhead. That means closure creation
930	and memory usage is not included in the figures.	1425	and memory usage is not included in the figures.
931		1426
932	I<invoke> is the time, in microseconds, used to invoke a simple	1427	I<invoke> is the time, in microseconds, used to invoke a simple
933	callback. The callback simply counts down a Perl variable and after it was	1428	callback. The callback simply counts down a Perl variable and after it was
934	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1429	invoked "watcher" times, it would C<< ->send >> a condvar once to
935	signal the end of this phase.	1430	signal the end of this phase.
936		1431
937	I<destroy> is the time, in microseconds, that it takes to destroy a single	1432	I<destroy> is the time, in microseconds, that it takes to destroy a single
938	watcher.	1433	watcher.
939		1434
940	=head2 Results	1435	=head3 Results
941		1436
942	name watchers bytes create invoke destroy comment	1437	name watchers bytes create invoke destroy comment
943	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1438	EV/EV 400000 244 0.56 0.46 0.31 EV native interface
944	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1439	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers
945	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1440	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal
946	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1441	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation
947	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1442	Event/Event 16000 516 31.88 31.30 0.85 Event native interface
948	Event/Any 16000 936 39.17 33.63 1.43 Event + AnyEvent watchers	1443	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers
949	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1444	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour
950	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1445	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers
951	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1446	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event
952	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1447	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select
953		1448
954	=head2 Discussion	1449	=head3 Discussion
955		1450
956	The benchmark does I<not> measure scalability of the event loop very	1451	The benchmark does I<not> measure scalability of the event loop very
957	well. For example, a select-based event loop (such as the pure perl one)	1452	well. For example, a select-based event loop (such as the pure perl one)
958	can never compete with an event loop that uses epoll when the number of	1453	can never compete with an event loop that uses epoll when the number of
959	file descriptors grows high. In this benchmark, all events become ready at	1454	file descriptors grows high. In this benchmark, all events become ready at
960	the same time, so select/poll-based implementations get an unnatural speed	1455	the same time, so select/poll-based implementations get an unnatural speed
961	boost.	1456	boost.
		1457
		1458	Also, note that the number of watchers usually has a nonlinear effect on
		1459	overall speed, that is, creating twice as many watchers doesn't take twice
		1460	the time - usually it takes longer. This puts event loops tested with a
		1461	higher number of watchers at a disadvantage.
		1462
		1463	To put the range of results into perspective, consider that on the
		1464	benchmark machine, handling an event takes roughly 1600 CPU cycles with
		1465	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
		1466	cycles with POE.
962		1467
963	C<EV> is the sole leader regarding speed and memory use, which are both	1468	C<EV> is the sole leader regarding speed and memory use, which are both
964	maximal/minimal, respectively. Even when going through AnyEvent, it uses	1469	maximal/minimal, respectively. Even when going through AnyEvent, it uses
965	far less memory than any other event loop and is still faster than Event	1470	far less memory than any other event loop and is still faster than Event
966	natively.	1471	natively.
…		…
989	file descriptor is dup()ed for each watcher. This shows that the dup()	1494	file descriptor is dup()ed for each watcher. This shows that the dup()
990	employed by some adaptors is not a big performance issue (it does incur a	1495	employed by some adaptors is not a big performance issue (it does incur a
991	hidden memory cost inside the kernel which is not reflected in the figures	1496	hidden memory cost inside the kernel which is not reflected in the figures
992	above).	1497	above).
993		1498
994	C<POE>, regardless of underlying event loop (whether using its pure	1499	C<POE>, regardless of underlying event loop (whether using its pure perl
995	perl select-based backend or the Event module, the POE-EV backend	1500	select-based backend or the Event module, the POE-EV backend couldn't
996	couldn't be tested because it wasn't working) shows abysmal performance	1501	be tested because it wasn't working) shows abysmal performance and
997	and memory usage: Watchers use almost 30 times as much memory as	1502	memory usage with AnyEvent: Watchers use almost 30 times as much memory
998	EV watchers, and 10 times as much memory as Event (the high memory	1503	as EV watchers, and 10 times as much memory as Event (the high memory
999	requirements are caused by requiring a session for each watcher). Watcher	1504	requirements are caused by requiring a session for each watcher). Watcher
1000	invocation speed is almost 900 times slower than with AnyEvent's pure perl	1505	invocation speed is almost 900 times slower than with AnyEvent's pure perl
		1506	implementation.
		1507
1001	implementation. The design of the POE adaptor class in AnyEvent can not	1508	The design of the POE adaptor class in AnyEvent can not really account
1002	really account for this, as session creation overhead is small compared	1509	for the performance issues, though, as session creation overhead is
1003	to execution of the state machine, which is coded pretty optimally within	1510	small compared to execution of the state machine, which is coded pretty
1004	L<AnyEvent::Impl::POE>. POE simply seems to be abysmally slow.	1511	optimally within L<AnyEvent::Impl::POE> (and while everybody agrees that
		1512	using multiple sessions is not a good approach, especially regarding
		1513	memory usage, even the author of POE could not come up with a faster
		1514	design).
1005		1515
1006	=head2 Summary	1516	=head3 Summary
1007		1517
1008	=over 4	1518	=over 4
1009		1519
1010	=item * Using EV through AnyEvent is faster than any other event loop	1520	=item * Using EV through AnyEvent is faster than any other event loop
1011	(even when used without AnyEvent), but most event loops have acceptable	1521	(even when used without AnyEvent), but most event loops have acceptable
…		…
1018	=item * You should avoid POE like the plague if you want performance or	1528	=item * You should avoid POE like the plague if you want performance or
1019	reasonable memory usage.	1529	reasonable memory usage.
1020		1530
1021	=back	1531	=back
1022		1532
		1533	=head2 BENCHMARKING THE LARGE SERVER CASE
		1534
		1535	This benchmark actually benchmarks the event loop itself. It works by
		1536	creating a number of "servers": each server consists of a socket pair, a
		1537	timeout watcher that gets reset on activity (but never fires), and an I/O
		1538	watcher waiting for input on one side of the socket. Each time the socket
		1539	watcher reads a byte it will write that byte to a random other "server".
		1540
		1541	The effect is that there will be a lot of I/O watchers, only part of which
		1542	are active at any one point (so there is a constant number of active
		1543	fds for each loop iteration, but which fds these are is random). The
		1544	timeout is reset each time something is read because that reflects how
		1545	most timeouts work (and puts extra pressure on the event loops).
		1546
		1547	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
		1548	(1%) are active. This mirrors the activity of large servers with many
		1549	connections, most of which are idle at any one point in time.
		1550
		1551	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
		1552	distribution.
		1553
		1554	=head3 Explanation of the columns
		1555
		1556	I<sockets> is the number of sockets, and twice the number of "servers" (as
		1557	each server has a read and write socket end).
		1558
		1559	I<create> is the time it takes to create a socket pair (which is
		1560	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
		1561
		1562	I<request>, the most important value, is the time it takes to handle a
		1563	single "request", that is, reading the token from the pipe and forwarding
		1564	it to another server. This includes deleting the old timeout and creating
		1565	a new one that moves the timeout into the future.
		1566
		1567	=head3 Results
		1568
		1569	name sockets create request
		1570	EV 20000 69.01 11.16
		1571	Perl 20000 73.32 35.87
		1572	Event 20000 212.62 257.32
		1573	Glib 20000 651.16 1896.30
		1574	POE 20000 349.67 12317.24 uses POE::Loop::Event
		1575
		1576	=head3 Discussion
		1577
		1578	This benchmark I<does> measure scalability and overall performance of the
		1579	particular event loop.
		1580
		1581	EV is again fastest. Since it is using epoll on my system, the setup time
		1582	is relatively high, though.
		1583
		1584	Perl surprisingly comes second. It is much faster than the C-based event
		1585	loops Event and Glib.
		1586
		1587	Event suffers from high setup time as well (look at its code and you will
		1588	understand why). Callback invocation also has a high overhead compared to
		1589	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
		1590	uses select or poll in basically all documented configurations.
		1591
		1592	Glib is hit hard by its quadratic behaviour w.r.t. many watchers. It
		1593	clearly fails to perform with many filehandles or in busy servers.
		1594
		1595	POE is still completely out of the picture, taking over 1000 times as long
		1596	as EV, and over 100 times as long as the Perl implementation, even though
		1597	it uses a C-based event loop in this case.
		1598
		1599	=head3 Summary
		1600
		1601	=over 4
		1602
		1603	=item * The pure perl implementation performs extremely well.
		1604
		1605	=item * Avoid Glib or POE in large projects where performance matters.
		1606
		1607	=back
		1608
		1609	=head2 BENCHMARKING SMALL SERVERS
		1610
		1611	While event loops should scale (and select-based ones do not...) even to
		1612	large servers, most programs we (or I :) actually write have only a few
		1613	I/O watchers.
		1614
		1615	In this benchmark, I use the same benchmark program as in the large server
		1616	case, but it uses only eight "servers", of which three are active at any
		1617	one time. This should reflect performance for a small server relatively
		1618	well.
		1619
		1620	The columns are identical to the previous table.
		1621
		1622	=head3 Results
		1623
		1624	name sockets create request
		1625	EV 16 20.00 6.54
		1626	Perl 16 25.75 12.62
		1627	Event 16 81.27 35.86
		1628	Glib 16 32.63 15.48
		1629	POE 16 261.87 276.28 uses POE::Loop::Event
		1630
		1631	=head3 Discussion
		1632
		1633	The benchmark tries to test the performance of a typical small
		1634	server. While knowing how various event loops perform is interesting, keep
		1635	in mind that their overhead in this case is usually not as important, due
		1636	to the small absolute number of watchers (that is, you need efficiency and
		1637	speed most when you have lots of watchers, not when you only have a few of
		1638	them).
		1639
		1640	EV is again fastest.
		1641
		1642	Perl again comes second. It is noticeably faster than the C-based event
		1643	loops Event and Glib, although the difference is too small to really
		1644	matter.
		1645
		1646	POE also performs much better in this case, but is is still far behind the
		1647	others.
		1648
		1649	=head3 Summary
		1650
		1651	=over 4
		1652
		1653	=item * C-based event loops perform very well with small number of
		1654	watchers, as the management overhead dominates.
		1655
		1656	=back
		1657
1023		1658
1024	=head1 FORK	1659	=head1 FORK
1025		1660
1026	Most event libraries are not fork-safe. The ones who are usually are	1661	Most event libraries are not fork-safe. The ones who are usually are
1027	because they are so inefficient. Only L<EV> is fully fork-aware.	1662	because they rely on inefficient but fork-safe C<select> or C<poll>
		1663	calls. Only L<EV> is fully fork-aware.
1028		1664
1029	If you have to fork, you must either do so I<before> creating your first	1665	If you have to fork, you must either do so I<before> creating your first
1030	watcher OR you must not use AnyEvent at all in the child.	1666	watcher OR you must not use AnyEvent at all in the child.
1031		1667
1032		1668
…		…
1040	specified in the variable.	1676	specified in the variable.
1041		1677
1042	You can make AnyEvent completely ignore this variable by deleting it	1678	You can make AnyEvent completely ignore this variable by deleting it
1043	before the first watcher gets created, e.g. with a C<BEGIN> block:	1679	before the first watcher gets created, e.g. with a C<BEGIN> block:
1044		1680
1045	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1681	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1046		1682
1047	use AnyEvent;	1683	use AnyEvent;
		1684
		1685	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
		1686	be used to probe what backend is used and gain other information (which is
		1687	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
		1688
		1689
		1690	=head1 BUGS
		1691
		1692	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		1693	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		1694	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		1695	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as
		1696	pronounced).
1048		1697
1049		1698
1050	=head1 SEE ALSO	1699	=head1 SEE ALSO
1051		1700
1052	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,	1701	Utility functions: L<AnyEvent::Util>.
1053	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,	1702
		1703	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1054	L<Event::Lib>, L<Qt>, L<POE>.	1704	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1055		1705
1056	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,	1706	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1057	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,	1707	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1058	L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>,	1708	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1059	L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>.	1709	L<AnyEvent::Impl::POE>.
1060		1710
		1711	Non-blocking file handles, sockets, TCP clients and
		1712	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1713
		1714	Asynchronous DNS: L<AnyEvent::DNS>.
		1715
		1716	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
		1717
1061	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1718	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1062		1719
1063		1720
1064	=head1 AUTHOR	1721	=head1 AUTHOR
1065		1722
1066	Marc Lehmann <schmorp@schmorp.de>	1723	Marc Lehmann <schmorp@schmorp.de>
1067	http://home.schmorp.de/	1724	http://home.schmorp.de/
1068		1725
1069	=cut	1726	=cut
1070		1727
1071	1	1728	1
1072		1729

Diff Legend

–	Removed lines
+	Added lines
<	Changed lines
>	Changed lines