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Revision 1.100 by elmex, Sun Apr 27 19:15:43 2008 UTC vs.
Revision 1.167 by root, Tue Jul 8 23:44:51 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	#TODO#
72
73	Net::IRC3
74	AnyEvent::HTTPD
75	AnyEvent::DNS
76	IO::AnyEvent
77	Net::FPing
78	Net::XMPP2
79	Coro
80
81	AnyEvent::IRC
82	AnyEvent::HTTPD
83	AnyEvent::DNS
84	AnyEvent::Handle
85	AnyEvent::Socket
86	AnyEvent::FPing
87	AnyEvent::XMPP
88	AnyEvent::SNMP
89	Coro
90		82
91	=head1 DESCRIPTION	83	=head1 DESCRIPTION
92		84
93	L<AnyEvent> provides an identical interface to multiple event loops. This	85	L<AnyEvent> provides an identical interface to multiple event loops. This
94	allows module authors to utilise an event loop without forcing module	86	allows module authors to utilise an event loop without forcing module
…		…
98	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>
99	module.	91	module.
100		92
101	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
102	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
103	following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>,	95	following modules is already loaded: L<EV>,
104	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>,
105	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
106	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
107	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
108	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
…		…
122	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
123	use AnyEvent so their modules work together with others seamlessly...	115	use AnyEvent so their modules work together with others seamlessly...
124		116
125	The pure-perl implementation of AnyEvent is called	117	The pure-perl implementation of AnyEvent is called
126	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
127	explicitly.	119	explicitly and enjoy the high availability of that event loop :)
128		120
129	=head1 WATCHERS	121	=head1 WATCHERS
130		122
131	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
132	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
133	the callback to call, the filehandle to watch, etc.	125	the callback to call, the file handle to watch, etc.
134		126
135	These watchers are normal Perl objects with normal Perl lifetime. After	127	These watchers are normal Perl objects with normal Perl lifetime. After
136	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
137	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
138	is in control).	130	is in control).
…		…
146	Many watchers either are used with "recursion" (repeating timers for	138	Many watchers either are used with "recursion" (repeating timers for
147	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.
148		140
149	An any way to achieve that is this pattern:	141	An any way to achieve that is this pattern:
150		142
151	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	143	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
152	# you can use $w here, for example to undef it	144	# you can use $w here, for example to undef it
153	undef $w;	145	undef $w;
154	});	146	});
155		147
156	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,
157	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
158	declared.	150	declared.
159		151
160	=head2 I/O WATCHERS	152	=head2 I/O WATCHERS
161		153
162	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
163	with the following mandatory key-value pairs as arguments:	155	with the following mandatory key-value pairs as arguments:
164		156
165	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
166	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>
167	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
168	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
169	becomes ready.	161	callback to invoke each time the file handle becomes ready.
170		162
171	Although the callback might get passed parameters, their value and	163	Although the callback might get passed parameters, their value and
172	presence is undefined and you cannot rely on them. Portable AnyEvent	164	presence is undefined and you cannot rely on them. Portable AnyEvent
173	callbacks cannot use arguments passed to I/O watcher callbacks.	165	callbacks cannot use arguments passed to I/O watcher callbacks.
174		166
…		…
178		170
179	Some event loops issue spurious readyness notifications, so you should	171	Some event loops issue spurious readyness notifications, so you should
180	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
181	handles.	173	handles.
182		174
183	Example:
184
185	# 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
186	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	178	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
187	chomp (my $input = <STDIN>);	179	chomp (my $input = <STDIN>);
188	warn "read: $input\n";	180	warn "read: $input\n";
189	undef $w;	181	undef $w;
190	});	182	});
…		…
200		192
201	Although the callback might get passed parameters, their value and	193	Although the callback might get passed parameters, their value and
202	presence is undefined and you cannot rely on them. Portable AnyEvent	194	presence is undefined and you cannot rely on them. Portable AnyEvent
203	callbacks cannot use arguments passed to time watcher callbacks.	195	callbacks cannot use arguments passed to time watcher callbacks.
204		196
205	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
206	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
207	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.
208		202
209	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.
210		206
211	# fire an event after 7.7 seconds	207	Example: fire an event after 7.7 seconds.
		208
212	my $w = AnyEvent->timer (after => 7.7, cb => sub {	209	my $w = AnyEvent->timer (after => 7.7, cb => sub {
213	warn "timeout\n";	210	warn "timeout\n";
214	});	211	});
215		212
216	# to cancel the timer:	213	# to cancel the timer:
217	undef $w;	214	undef $w;
218		215
219	Example 2:
220
221	# 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.
222	my $w;
223		217
224	my $cb = sub {
225	# cancel the old timer while creating a new one
226	$w = AnyEvent->timer (after => 1, cb => $cb);	218	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		219	warn "timeout\n";
227	};	220	};
228
229	# start the "loop" by creating the first watcher
230	$w = AnyEvent->timer (after => 0.5, cb => $cb);
231		221
232	=head3 TIMING ISSUES	222	=head3 TIMING ISSUES
233		223
234	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
235	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
…		…
247	timers.	237	timers.
248		238
249	AnyEvent always prefers relative timers, if available, matching the	239	AnyEvent always prefers relative timers, if available, matching the
250	AnyEvent API.	240	AnyEvent API.
251		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
252	=head2 SIGNAL WATCHERS	305	=head2 SIGNAL WATCHERS
253		306
254	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
255	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to	308	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
256	be invoked whenever a signal occurs.	309	callback to be invoked whenever a signal occurs.
257		310
258	Although the callback might get passed parameters, their value and	311	Although the callback might get passed parameters, their value and
259	presence is undefined and you cannot rely on them. Portable AnyEvent	312	presence is undefined and you cannot rely on them. Portable AnyEvent
260	callbacks cannot use arguments passed to signal watcher callbacks.	313	callbacks cannot use arguments passed to signal watcher callbacks.
261		314
262	Multiple signal occurances can be clumped together into one callback	315	Multiple signal occurrences can be clumped together into one callback
263	invocation, and callback invocation will be synchronous. synchronous means	316	invocation, and callback invocation will be synchronous. Synchronous means
264	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,
265	but it is guarenteed not to interrupt any other callbacks.	318	but it is guaranteed not to interrupt any other callbacks.
266		319
267	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
268	between multiple watchers.	321	between multiple watchers.
269		322
270	This watcher might use C<%SIG>, so programs overwriting those signals	323	This watcher might use C<%SIG>, so programs overwriting those signals
…		…
297	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
298	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	351	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
299		352
300	Example: fork a process and wait for it	353	Example: fork a process and wait for it
301		354
302	my $done = AnyEvent->condvar;	355	my $done = AnyEvent->condvar;
303		356
304	AnyEvent::detect; # force event module to be initialised
305
306	my $pid = fork or exit 5;	357	my $pid = fork or exit 5;
307		358
308	my $w = AnyEvent->child (	359	my $w = AnyEvent->child (
309	pid => $pid,	360	pid => $pid,
310	cb => sub {	361	cb => sub {
311	my ($pid, $status) = @_;	362	my ($pid, $status) = @_;
312	warn "pid $pid exited with status $status";	363	warn "pid $pid exited with status $status";
313	$done->broadcast;	364	$done->send;
314	},	365	},
315	);	366	);
316		367
317	# do something else, then wait for process exit	368	# do something else, then wait for process exit
318	$done->wait;	369	$done->recv;
319		370
320	=head2 CONDITION VARIABLES	371	=head2 CONDITION VARIABLES
321		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
322	Condition variables can be created by calling the C<< AnyEvent->condvar >>	383	Condition variables can be created by calling the C<< AnyEvent->condvar
323	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.
324		387
325	A condition variable waits for a condition - precisely that the C<<	388	After creation, the condition variable is "false" until it becomes "true"
326	->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).
327		392
328	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,
329	example, if you write a module that does asynchronous http requests,	401	for example, if you write a module that does asynchronous http requests,
330	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
331	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.
332		405
333	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,
334	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
335	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
336	->broadcast >> the "quit" event.	409	button of your app, which would C<< ->send >> the "quit" event.
337		410
338	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
339	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
340	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
341	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,
342	as this asks for trouble.	415	as this asks for trouble.
343		416
344	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.
345		458
346	=over 4	459	=over 4
347		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
348	=item $cv->wait	492	=item $cv->end
349		493
350	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 $cv->recv
		551
		552	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
351	called on c<$cv>, while servicing other watchers normally.	553	>> methods have been called on c<$cv>, while servicing other watchers
		554	normally.
352		555
353	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
354	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.
355		564
356	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
357	(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
358	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
359	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
360	condition variables with some kind of request results and supporting	569	condition variables with some kind of request results and supporting
361	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,
362	while still suppporting blocking waits if the caller so desires).	571	while still supporting blocking waits if the caller so desires).
363		572
364	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
365	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
366	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	575	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
367	can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and	576	can supply.
368	L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
369	from different coroutines, however).
370		577
371	=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).
372		583
373	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
374	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
375	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.
376		603
377	=back	604	=back
378
379	Example:
380
381	# wait till the result is ready
382	my $result_ready = AnyEvent->condvar;
383
384	# do something such as adding a timer
385	# or socket watcher the calls $result_ready->broadcast
386	# when the "result" is ready.
387	# in this case, we simply use a timer:
388	my $w = AnyEvent->timer (
389	after => 1,
390	cb => sub { $result_ready->broadcast },
391	);
392
393	# this "blocks" (while handling events) till the watcher
394	# calls broadcast
395	$result_ready->wait;
396		605
397	=head1 GLOBAL VARIABLES AND FUNCTIONS	606	=head1 GLOBAL VARIABLES AND FUNCTIONS
398		607
399	=over 4	608	=over 4
400		609
…		…
406	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	615	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
407	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	616	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
408		617
409	The known classes so far are:	618	The known classes so far are:
410		619
411	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
412	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
413	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).	620	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
414	AnyEvent::Impl::Event based on Event, second best choice.	621	AnyEvent::Impl::Event based on Event, second best choice.
		622	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
415	AnyEvent::Impl::Glib based on Glib, third-best choice.	623	AnyEvent::Impl::Glib based on Glib, third-best choice.
416	AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable.
417	AnyEvent::Impl::Tk based on Tk, very bad choice.	624	AnyEvent::Impl::Tk based on Tk, very bad choice.
418	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).	625	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
419	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	626	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
420	AnyEvent::Impl::POE based on POE, not generic enough for full support.	627	AnyEvent::Impl::POE based on POE, not generic enough for full support.
421		628
…		…
434	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	641	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
435	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
436	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
437	runtime.	644	runtime.
438		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
439	=back	667	=back
440		668
441	=head1 WHAT TO DO IN A MODULE	669	=head1 WHAT TO DO IN A MODULE
442		670
443	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
…		…
446	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
447	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
448	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
449	to load the event module first.	677	to load the event module first.
450		678
451	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
452	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
453	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
454	events is to stay interactive.	682	events is to stay interactive.
455		683
456	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
457	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
458	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 >>
459	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).
460		688
461	=head1 WHAT TO DO IN THE MAIN PROGRAM	689	=head1 WHAT TO DO IN THE MAIN PROGRAM
462		690
463	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
…		…
465		693
466	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
467	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
468	decide which implementation to chose if some module relies on it.	696	decide which implementation to chose if some module relies on it.
469		697
470	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
471	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
472	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
473	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
474	modules might create watchers when they are loaded, and AnyEvent will	702	modules might create watchers when they are loaded, and AnyEvent will
475	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
476	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.
477		705
478	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
479	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	707	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
480	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
481		726
482	=head1 OTHER MODULES	727	=head1 OTHER MODULES
483		728
484	L<AnyEvent> itself comes with useful utility modules:	729	The following is a non-exhaustive list of additional modules that use
485		730	AnyEvent and can therefore be mixed easily with other AnyEvent modules
486	To make it easier to do non-blocking IO the modules L<AnyEvent::Handle>	731	in the same program. Some of the modules come with AnyEvent, some are
487	and L<AnyEvent::Socket> are provided. L<AnyEvent::Handle> provides	732	available via CPAN.
488	read and write buffers and manages watchers for reads and writes.
489	L<AnyEvent::Socket> provides means to do non-blocking connects.
490
491	Aside from those there are these modules that support AnyEvent (and use it
492	for non-blocking IO):
493		733
494	=over 4	734	=over 4
495		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
496	=item L<AnyEvent::FastPing>	766	=item L<AnyEvent::FastPing>
497		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
498	=item L<Net::IRC3>	794	=item L<Net::IRC3>
499		795
		796	AnyEvent based IRC client module family.
		797
500	=item L<Net::XMPP2>	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.
501		818
502	=back	819	=back
503		820
504	=cut	821	=cut
505		822
…		…
508	no warnings;	825	no warnings;
509	use strict;	826	use strict;
510		827
511	use Carp;	828	use Carp;
512		829
513	our $VERSION = '3.3';	830	our $VERSION = 4.2;
514	our $MODEL;	831	our $MODEL;
515		832
516	our $AUTOLOAD;	833	our $AUTOLOAD;
517	our @ISA;	834	our @ISA;
518		835
		836	our @REGISTRY;
		837
		838	our $WIN32;
		839
		840	BEGIN {
		841	my $win32 = ! ! ($^O =~ /mswin32/i);
		842	eval "sub WIN32(){ $win32 }";
		843	}
		844
519	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	845	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
520		846
521	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	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
		854	}
522		855
523	my @models = (	856	my @models = (
524	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
525	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
526	[EV:: => AnyEvent::Impl::EV::],	857	[EV:: => AnyEvent::Impl::EV::],
527	[Event:: => AnyEvent::Impl::Event::],	858	[Event:: => AnyEvent::Impl::Event::],
528	[Glib:: => AnyEvent::Impl::Glib::],
529	[Tk:: => AnyEvent::Impl::Tk::],
530	[Wx:: => AnyEvent::Impl::POE::],
531	[Prima:: => AnyEvent::Impl::POE::],
532	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	859	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
533	# everything below here will not be autoprobed as the pureperl backend should work everywhere	860	# everything below here will not be autoprobed
		861	# as the pureperl backend should work everywhere
		862	# and is usually faster
		863	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		864	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
534	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	865	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
535	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	866	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
536	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	867	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
		868	[Wx:: => AnyEvent::Impl::POE::],
		869	[Prima:: => AnyEvent::Impl::POE::],
537	);	870	);
538		871
539	our %method = map +($_ => 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	}
540		895
541	sub detect() {	896	sub detect() {
542	unless ($MODEL) {	897	unless ($MODEL) {
543	no strict 'refs';	898	no strict 'refs';
		899	local $SIG{__DIE__};
544		900
545	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	901	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
546	my $model = "AnyEvent::Impl::$1";	902	my $model = "AnyEvent::Impl::$1";
547	if (eval "require $model") {	903	if (eval "require $model") {
548	$MODEL = $model;	904	$MODEL = $model;
…		…
578	last;	934	last;
579	}	935	}
580	}	936	}
581		937
582	$MODEL	938	$MODEL
583	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.";
584	}	940	}
585	}	941	}
586		942
587	unshift @ISA, $MODEL;
588	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	943	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		944
		945	if ($ENV{PERL_ANYEVENT_STRICT}) {
		946	unshift @AnyEvent::Base::Strict::ISA, $MODEL;
		947	unshift @ISA, AnyEvent::Base::Strict::
		948	} else {
		949	unshift @ISA, $MODEL;
		950	}
		951
		952	(shift @post_detect)->() while @post_detect;
589	}	953	}
590		954
591	$MODEL	955	$MODEL
592	}	956	}
593		957
…		…
603	$class->$func (@_);	967	$class->$func (@_);
604	}	968	}
605		969
606	package AnyEvent::Base;	970	package AnyEvent::Base;
607		971
		972	# default implementation for now and time
		973
		974	use Time::HiRes ();
		975
		976	sub time { Time::HiRes::time }
		977	sub now { Time::HiRes::time }
		978
608	# default implementation for ->condvar, ->wait, ->broadcast	979	# default implementation for ->condvar
609		980
610	sub condvar {	981	sub condvar {
611	bless \my $flag, "AnyEvent::Base::CondVar"	982	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
612	}
613
614	sub AnyEvent::Base::CondVar::broadcast {
615	${$_[0]}++;
616	}
617
618	sub AnyEvent::Base::CondVar::wait {
619	AnyEvent->one_event while !${$_[0]};
620	}	983	}
621		984
622	# default implementation for ->signal	985	# default implementation for ->signal
623		986
624	our %SIG_CB;	987	our %SIG_CB;
…		…
640	sub AnyEvent::Base::Signal::DESTROY {	1003	sub AnyEvent::Base::Signal::DESTROY {
641	my ($signal, $cb) = @{$_[0]};	1004	my ($signal, $cb) = @{$_[0]};
642		1005
643	delete $SIG_CB{$signal}{$cb};	1006	delete $SIG_CB{$signal}{$cb};
644		1007
645	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1008	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
646	}	1009	}
647		1010
648	# default implementation for ->child	1011	# default implementation for ->child
649		1012
650	our %PID_CB;	1013	our %PID_CB;
…		…
677	or Carp::croak "required option 'pid' is missing";	1040	or Carp::croak "required option 'pid' is missing";
678		1041
679	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1042	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
680		1043
681	unless ($WNOHANG) {	1044	unless ($WNOHANG) {
682	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1;	1045	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
683	}	1046	}
684		1047
685	unless ($CHLD_W) {	1048	unless ($CHLD_W) {
686	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1049	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
687	# child could be a zombie already, so make at least one round	1050	# child could be a zombie already, so make at least one round
…		…
696		1059
697	delete $PID_CB{$pid}{$cb};	1060	delete $PID_CB{$pid}{$cb};
698	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1061	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
699		1062
700	undef $CHLD_W unless keys %PID_CB;	1063	undef $CHLD_W unless keys %PID_CB;
		1064	}
		1065
		1066	package AnyEvent::CondVar;
		1067
		1068	our @ISA = AnyEvent::CondVar::Base::;
		1069
		1070	package AnyEvent::CondVar::Base;
		1071
		1072	use overload
		1073	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		1074	fallback => 1;
		1075
		1076	sub _send {
		1077	# nop
		1078	}
		1079
		1080	sub send {
		1081	my $cv = shift;
		1082	$cv->{_ae_sent} = [@_];
		1083	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		1084	$cv->_send;
		1085	}
		1086
		1087	sub croak {
		1088	$_[0]{_ae_croak} = $_[1];
		1089	$_[0]->send;
		1090	}
		1091
		1092	sub ready {
		1093	$_[0]{_ae_sent}
		1094	}
		1095
		1096	sub _wait {
		1097	AnyEvent->one_event while !$_[0]{_ae_sent};
		1098	}
		1099
		1100	sub recv {
		1101	$_[0]->_wait;
		1102
		1103	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		1104	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		1105	}
		1106
		1107	sub cb {
		1108	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		1109	$_[0]{_ae_cb}
		1110	}
		1111
		1112	sub begin {
		1113	++$_[0]{_ae_counter};
		1114	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		1115	}
		1116
		1117	sub end {
		1118	return if --$_[0]{_ae_counter};
		1119	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
		1120	}
		1121
		1122	# undocumented/compatibility with pre-3.4
		1123	*broadcast = \&send;
		1124	*wait = \&_wait;
		1125
		1126	package AnyEvent::Base::Strict;
		1127
		1128	use Carp qw(croak);
		1129
		1130	# supply checks for argument validity for many functions
		1131
		1132	sub io {
		1133	my $class = shift;
		1134	my %arg = @_;
		1135
		1136	ref $arg{cb}
		1137	or croak "AnyEvent->io called with illegal cb argument '$arg{cb}'";
		1138	delete $arg{cb};
		1139
		1140	fileno $arg{fh}
		1141	or croak "AnyEvent->io called with illegal fh argument '$arg{fh}'";
		1142	delete $arg{fh};
		1143
		1144	$arg{poll} =~ /^[rw]$/
		1145	or croak "AnyEvent->io called with illegal poll argument '$arg{poll}'";
		1146	delete $arg{poll};
		1147
		1148	croak "AnyEvent->io called with unsupported parameter(s) " . join ", ", keys %arg
		1149	if keys %arg;
		1150
		1151	$class->SUPER::io (@_)
		1152	}
		1153
		1154	sub timer {
		1155	my $class = shift;
		1156	my %arg = @_;
		1157
		1158	ref $arg{cb}
		1159	or croak "AnyEvent->timer called with illegal cb argument '$arg{cb}'";
		1160	delete $arg{cb};
		1161
		1162	exists $arg{after}
		1163	or croak "AnyEvent->timer called without mandatory 'after' parameter";
		1164	delete $arg{after};
		1165
		1166	$arg{interval} > 0 || !$arg{interval}
		1167	or croak "AnyEvent->timer called with illegal interval argument '$arg{interval}'";
		1168	delete $arg{interval};
		1169
		1170	croak "AnyEvent->timer called with unsupported parameter(s) " . join ", ", keys %arg
		1171	if keys %arg;
		1172
		1173	$class->SUPER::timer (@_)
		1174	}
		1175
		1176	sub signal {
		1177	my $class = shift;
		1178	my %arg = @_;
		1179
		1180	ref $arg{cb}
		1181	or croak "AnyEvent->signal called with illegal cb argument '$arg{cb}'";
		1182	delete $arg{cb};
		1183
		1184	eval "require POSIX; defined &POSIX::SIG$arg{signal}"
		1185	or croak "AnyEvent->signal called with illegal signal name '$arg{signal}'";
		1186	delete $arg{signal};
		1187
		1188	croak "AnyEvent->signal called with unsupported parameter(s) " . join ", ", keys %arg
		1189	if keys %arg;
		1190
		1191	$class->SUPER::signal (@_)
		1192	}
		1193
		1194	sub child {
		1195	my $class = shift;
		1196	my %arg = @_;
		1197
		1198	ref $arg{cb}
		1199	or croak "AnyEvent->signal called with illegal cb argument '$arg{cb}'";
		1200	delete $arg{cb};
		1201
		1202	$arg{pid} =~ /^-?\d+$/
		1203	or croak "AnyEvent->signal called with illegal pid value '$arg{pid}'";
		1204	delete $arg{pid};
		1205
		1206	croak "AnyEvent->signal called with unsupported parameter(s) " . join ", ", keys %arg
		1207	if keys %arg;
		1208
		1209	$class->SUPER::child (@_)
		1210	}
		1211
		1212	sub condvar {
		1213	my $class = shift;
		1214	my %arg = @_;
		1215
		1216	!exists $arg{cb} or ref $arg{cb}
		1217	or croak "AnyEvent->condvar called with illegal cb argument '$arg{cb}'";
		1218	delete $arg{cb};
		1219
		1220	croak "AnyEvent->condvar called with unsupported parameter(s) " . join ", ", keys %arg
		1221	if keys %arg;
		1222
		1223	$class->SUPER::condvar (@_)
		1224	}
		1225
		1226	sub time {
		1227	my $class = shift;
		1228
		1229	@_
		1230	and croak "AnyEvent->time wrongly called with paramaters";
		1231
		1232	$class->SUPER::time (@_)
		1233	}
		1234
		1235	sub now {
		1236	my $class = shift;
		1237
		1238	@_
		1239	and croak "AnyEvent->now wrongly called with paramaters";
		1240
		1241	$class->SUPER::now (@_)
701	}	1242	}
702		1243
703	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1244	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
704		1245
705	This is an advanced topic that you do not normally need to use AnyEvent in	1246	This is an advanced topic that you do not normally need to use AnyEvent in
…		…
760	C<PERL_ANYEVENT_MODEL>.	1301	C<PERL_ANYEVENT_MODEL>.
761		1302
762	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1303	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
763	model it chooses.	1304	model it chooses.
764		1305
		1306	=item C<PERL_ANYEVENT_STRICT>
		1307
		1308	AnyEvent does not do much argument checking by default, as thorough
		1309	argument checking is very costly. Setting this variable to a true value
		1310	will cause AnyEvent to thoroughly check the arguments passed to most
		1311	method calls and croaks if it finds any problems. In other words, enables
		1312	"strict" mode. Unlike C<use strict> it is definitely recommended ot keep
		1313	it off in production.
		1314
765	=item C<PERL_ANYEVENT_MODEL>	1315	=item C<PERL_ANYEVENT_MODEL>
766		1316
767	This can be used to specify the event model to be used by AnyEvent, before	1317	This can be used to specify the event model to be used by AnyEvent, before
768	autodetection and -probing kicks in. It must be a string consisting	1318	auto detection and -probing kicks in. It must be a string consisting
769	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1319	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
770	and the resulting module name is loaded and if the load was successful,	1320	and the resulting module name is loaded and if the load was successful,
771	used as event model. If it fails to load AnyEvent will proceed with	1321	used as event model. If it fails to load AnyEvent will proceed with
772	autodetection and -probing.	1322	auto detection and -probing.
773		1323
774	This functionality might change in future versions.	1324	This functionality might change in future versions.
775		1325
776	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1326	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
777	could start your program like this:	1327	could start your program like this:
778		1328
779	PERL_ANYEVENT_MODEL=Perl perl ...	1329	PERL_ANYEVENT_MODEL=Perl perl ...
		1330
		1331	=item C<PERL_ANYEVENT_PROTOCOLS>
		1332
		1333	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1334	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1335	of auto probing).
		1336
		1337	Must be set to a comma-separated list of protocols or address families,
		1338	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1339	used, and preference will be given to protocols mentioned earlier in the
		1340	list.
		1341
		1342	This variable can effectively be used for denial-of-service attacks
		1343	against local programs (e.g. when setuid), although the impact is likely
		1344	small, as the program has to handle connection errors already-
		1345
		1346	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1347	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1348	- only support IPv4, never try to resolve or contact IPv6
		1349	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1350	IPv6, but prefer IPv6 over IPv4.
		1351
		1352	=item C<PERL_ANYEVENT_EDNS0>
		1353
		1354	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1355	for DNS. This extension is generally useful to reduce DNS traffic, but
		1356	some (broken) firewalls drop such DNS packets, which is why it is off by
		1357	default.
		1358
		1359	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1360	EDNS0 in its DNS requests.
		1361
		1362	=item C<PERL_ANYEVENT_MAX_FORKS>
		1363
		1364	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1365	will create in parallel.
780		1366
781	=back	1367	=back
782		1368
783	=head1 EXAMPLE PROGRAM	1369	=head1 EXAMPLE PROGRAM
784		1370
…		…
795	poll => 'r',	1381	poll => 'r',
796	cb => sub {	1382	cb => sub {
797	warn "io event <$_[0]>\n"; # will always output <r>	1383	warn "io event <$_[0]>\n"; # will always output <r>
798	chomp (my $input = <STDIN>); # read a line	1384	chomp (my $input = <STDIN>); # read a line
799	warn "read: $input\n"; # output what has been read	1385	warn "read: $input\n"; # output what has been read
800	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1386	$cv->send if $input =~ /^q/i; # quit program if /^q/i
801	},	1387	},
802	);	1388	);
803		1389
804	my $time_watcher; # can only be used once	1390	my $time_watcher; # can only be used once
805		1391
…		…
810	});	1396	});
811	}	1397	}
812		1398
813	new_timer; # create first timer	1399	new_timer; # create first timer
814		1400
815	$cv->wait; # wait until user enters /^q/i	1401	$cv->recv; # wait until user enters /^q/i
816		1402
817	=head1 REAL-WORLD EXAMPLE	1403	=head1 REAL-WORLD EXAMPLE
818		1404
819	Consider the L<Net::FCP> module. It features (among others) the following	1405	Consider the L<Net::FCP> module. It features (among others) the following
820	API calls, which are to freenet what HTTP GET requests are to http:	1406	API calls, which are to freenet what HTTP GET requests are to http:
…		…
870	syswrite $txn->{fh}, $txn->{request}	1456	syswrite $txn->{fh}, $txn->{request}
871	or die "connection or write error";	1457	or die "connection or write error";
872	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1458	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
873		1459
874	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1460	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
875	result and signals any possible waiters that the request ahs finished:	1461	result and signals any possible waiters that the request has finished:
876		1462
877	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1463	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
878		1464
879	if (end-of-file or data complete) {	1465	if (end-of-file or data complete) {
880	$txn->{result} = $txn->{buf};	1466	$txn->{result} = $txn->{buf};
881	$txn->{finished}->broadcast;	1467	$txn->{finished}->send;
882	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1468	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
883	}	1469	}
884		1470
885	The C<result> method, finally, just waits for the finished signal (if the	1471	The C<result> method, finally, just waits for the finished signal (if the
886	request was already finished, it doesn't wait, of course, and returns the	1472	request was already finished, it doesn't wait, of course, and returns the
887	data:	1473	data:
888		1474
889	$txn->{finished}->wait;	1475	$txn->{finished}->recv;
890	return $txn->{result};	1476	return $txn->{result};
891		1477
892	The actual code goes further and collects all errors (C<die>s, exceptions)	1478	The actual code goes further and collects all errors (C<die>s, exceptions)
893	that occured during request processing. The C<result> method detects	1479	that occurred during request processing. The C<result> method detects
894	whether an exception as thrown (it is stored inside the $txn object)	1480	whether an exception as thrown (it is stored inside the $txn object)
895	and just throws the exception, which means connection errors and other	1481	and just throws the exception, which means connection errors and other
896	problems get reported tot he code that tries to use the result, not in a	1482	problems get reported tot he code that tries to use the result, not in a
897	random callback.	1483	random callback.
898		1484
…		…
929		1515
930	my $quit = AnyEvent->condvar;	1516	my $quit = AnyEvent->condvar;
931		1517
932	$fcp->txn_client_get ($url)->cb (sub {	1518	$fcp->txn_client_get ($url)->cb (sub {
933	...	1519	...
934	$quit->broadcast;	1520	$quit->send;
935	});	1521	});
936		1522
937	$quit->wait;	1523	$quit->recv;
938		1524
939		1525
940	=head1 BENCHMARKS	1526	=head1 BENCHMARKS
941		1527
942	To give you an idea of the performance and overheads that AnyEvent adds	1528	To give you an idea of the performance and overheads that AnyEvent adds
…		…
944	of various event loops I prepared some benchmarks.	1530	of various event loops I prepared some benchmarks.
945		1531
946	=head2 BENCHMARKING ANYEVENT OVERHEAD	1532	=head2 BENCHMARKING ANYEVENT OVERHEAD
947		1533
948	Here is a benchmark of various supported event models used natively and	1534	Here is a benchmark of various supported event models used natively and
949	through anyevent. The benchmark creates a lot of timers (with a zero	1535	through AnyEvent. The benchmark creates a lot of timers (with a zero
950	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	1536	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
951	which it is), lets them fire exactly once and destroys them again.	1537	which it is), lets them fire exactly once and destroys them again.
952		1538
953	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1539	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
954	distribution.	1540	distribution.
…		…
971	all watchers, to avoid adding memory overhead. That means closure creation	1557	all watchers, to avoid adding memory overhead. That means closure creation
972	and memory usage is not included in the figures.	1558	and memory usage is not included in the figures.
973		1559
974	I<invoke> is the time, in microseconds, used to invoke a simple	1560	I<invoke> is the time, in microseconds, used to invoke a simple
975	callback. The callback simply counts down a Perl variable and after it was	1561	callback. The callback simply counts down a Perl variable and after it was
976	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1562	invoked "watcher" times, it would C<< ->send >> a condvar once to
977	signal the end of this phase.	1563	signal the end of this phase.
978		1564
979	I<destroy> is the time, in microseconds, that it takes to destroy a single	1565	I<destroy> is the time, in microseconds, that it takes to destroy a single
980	watcher.	1566	watcher.
981		1567
…		…
1041	file descriptor is dup()ed for each watcher. This shows that the dup()	1627	file descriptor is dup()ed for each watcher. This shows that the dup()
1042	employed by some adaptors is not a big performance issue (it does incur a	1628	employed by some adaptors is not a big performance issue (it does incur a
1043	hidden memory cost inside the kernel which is not reflected in the figures	1629	hidden memory cost inside the kernel which is not reflected in the figures
1044	above).	1630	above).
1045		1631
1046	C<POE>, regardless of underlying event loop (whether using its pure	1632	C<POE>, regardless of underlying event loop (whether using its pure perl
1047	perl select-based backend or the Event module, the POE-EV backend	1633	select-based backend or the Event module, the POE-EV backend couldn't
1048	couldn't be tested because it wasn't working) shows abysmal performance	1634	be tested because it wasn't working) shows abysmal performance and
1049	and memory usage: Watchers use almost 30 times as much memory as	1635	memory usage with AnyEvent: Watchers use almost 30 times as much memory
1050	EV watchers, and 10 times as much memory as Event (the high memory	1636	as EV watchers, and 10 times as much memory as Event (the high memory
1051	requirements are caused by requiring a session for each watcher). Watcher	1637	requirements are caused by requiring a session for each watcher). Watcher
1052	invocation speed is almost 900 times slower than with AnyEvent's pure perl	1638	invocation speed is almost 900 times slower than with AnyEvent's pure perl
		1639	implementation.
		1640
1053	implementation. The design of the POE adaptor class in AnyEvent can not	1641	The design of the POE adaptor class in AnyEvent can not really account
1054	really account for this, as session creation overhead is small compared	1642	for the performance issues, though, as session creation overhead is
1055	to execution of the state machine, which is coded pretty optimally within	1643	small compared to execution of the state machine, which is coded pretty
1056	L<AnyEvent::Impl::POE>. POE simply seems to be abysmally slow.	1644	optimally within L<AnyEvent::Impl::POE> (and while everybody agrees that
		1645	using multiple sessions is not a good approach, especially regarding
		1646	memory usage, even the author of POE could not come up with a faster
		1647	design).
1057		1648
1058	=head3 Summary	1649	=head3 Summary
1059		1650
1060	=over 4	1651	=over 4
1061		1652
…		…
1072		1663
1073	=back	1664	=back
1074		1665
1075	=head2 BENCHMARKING THE LARGE SERVER CASE	1666	=head2 BENCHMARKING THE LARGE SERVER CASE
1076		1667
1077	This benchmark atcually benchmarks the event loop itself. It works by	1668	This benchmark actually benchmarks the event loop itself. It works by
1078	creating a number of "servers": each server consists of a socketpair, a	1669	creating a number of "servers": each server consists of a socket pair, a
1079	timeout watcher that gets reset on activity (but never fires), and an I/O	1670	timeout watcher that gets reset on activity (but never fires), and an I/O
1080	watcher waiting for input on one side of the socket. Each time the socket	1671	watcher waiting for input on one side of the socket. Each time the socket
1081	watcher reads a byte it will write that byte to a random other "server".	1672	watcher reads a byte it will write that byte to a random other "server".
1082		1673
1083	The effect is that there will be a lot of I/O watchers, only part of which	1674	The effect is that there will be a lot of I/O watchers, only part of which
1084	are active at any one point (so there is a constant number of active	1675	are active at any one point (so there is a constant number of active
1085	fds for each loop iterstaion, but which fds these are is random). The	1676	fds for each loop iteration, but which fds these are is random). The
1086	timeout is reset each time something is read because that reflects how	1677	timeout is reset each time something is read because that reflects how
1087	most timeouts work (and puts extra pressure on the event loops).	1678	most timeouts work (and puts extra pressure on the event loops).
1088		1679
1089	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1680	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1090	(1%) are active. This mirrors the activity of large servers with many	1681	(1%) are active. This mirrors the activity of large servers with many
1091	connections, most of which are idle at any one point in time.	1682	connections, most of which are idle at any one point in time.
1092		1683
1093	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1684	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1094	distribution.	1685	distribution.
…		…
1096	=head3 Explanation of the columns	1687	=head3 Explanation of the columns
1097		1688
1098	I<sockets> is the number of sockets, and twice the number of "servers" (as	1689	I<sockets> is the number of sockets, and twice the number of "servers" (as
1099	each server has a read and write socket end).	1690	each server has a read and write socket end).
1100		1691
1101	I<create> is the time it takes to create a socketpair (which is	1692	I<create> is the time it takes to create a socket pair (which is
1102	nontrivial) and two watchers: an I/O watcher and a timeout watcher.	1693	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1103		1694
1104	I<request>, the most important value, is the time it takes to handle a	1695	I<request>, the most important value, is the time it takes to handle a
1105	single "request", that is, reading the token from the pipe and forwarding	1696	single "request", that is, reading the token from the pipe and forwarding
1106	it to another server. This includes deleting the old timeout and creating	1697	it to another server. This includes deleting the old timeout and creating
…		…
1140		1731
1141	=head3 Summary	1732	=head3 Summary
1142		1733
1143	=over 4	1734	=over 4
1144		1735
1145	=item * The pure perl implementation performs extremely well, considering	1736	=item * The pure perl implementation performs extremely well.
1146	that it uses select.
1147		1737
1148	=item * Avoid Glib or POE in large projects where performance matters.	1738	=item * Avoid Glib or POE in large projects where performance matters.
1149		1739
1150	=back	1740	=back
1151		1741
…		…
1180	speed most when you have lots of watchers, not when you only have a few of	1770	speed most when you have lots of watchers, not when you only have a few of
1181	them).	1771	them).
1182		1772
1183	EV is again fastest.	1773	EV is again fastest.
1184		1774
1185	The C-based event loops Event and Glib come in second this time, as the	1775	Perl again comes second. It is noticeably faster than the C-based event
1186	overhead of running an iteration is much smaller in C than in Perl (little	1776	loops Event and Glib, although the difference is too small to really
1187	code to execute in the inner loop, and perl's function calling overhead is	1777	matter.
1188	high, and updating all the data structures is costly).
1189
1190	The pure perl event loop is much slower, but still competitive.
1191		1778
1192	POE also performs much better in this case, but is is still far behind the	1779	POE also performs much better in this case, but is is still far behind the
1193	others.	1780	others.
1194		1781
1195	=head3 Summary	1782	=head3 Summary
…		…
1203		1790
1204		1791
1205	=head1 FORK	1792	=head1 FORK
1206		1793
1207	Most event libraries are not fork-safe. The ones who are usually are	1794	Most event libraries are not fork-safe. The ones who are usually are
1208	because they are so inefficient. Only L<EV> is fully fork-aware.	1795	because they rely on inefficient but fork-safe C<select> or C<poll>
		1796	calls. Only L<EV> is fully fork-aware.
1209		1797
1210	If you have to fork, you must either do so I<before> creating your first	1798	If you have to fork, you must either do so I<before> creating your first
1211	watcher OR you must not use AnyEvent at all in the child.	1799	watcher OR you must not use AnyEvent at all in the child.
1212		1800
1213		1801
…		…
1221	specified in the variable.	1809	specified in the variable.
1222		1810
1223	You can make AnyEvent completely ignore this variable by deleting it	1811	You can make AnyEvent completely ignore this variable by deleting it
1224	before the first watcher gets created, e.g. with a C<BEGIN> block:	1812	before the first watcher gets created, e.g. with a C<BEGIN> block:
1225		1813
1226	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1814	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1227		1815
1228	use AnyEvent;	1816	use AnyEvent;
		1817
		1818	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
		1819	be used to probe what backend is used and gain other information (which is
		1820	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1821	$ENV{PERL_ANYEGENT_STRICT}.
		1822
		1823
		1824	=head1 BUGS
		1825
		1826	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		1827	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		1828	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		1829	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as
		1830	pronounced).
1229		1831
1230		1832
1231	=head1 SEE ALSO	1833	=head1 SEE ALSO
1232		1834
1233	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,	1835	Utility functions: L<AnyEvent::Util>.
1234	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,	1836
		1837	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1235	L<Event::Lib>, L<Qt>, L<POE>.	1838	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1236		1839
1237	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,	1840	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1238	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,	1841	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1239	L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>,	1842	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1240	L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>.	1843	L<AnyEvent::Impl::POE>.
1241		1844
		1845	Non-blocking file handles, sockets, TCP clients and
		1846	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1847
		1848	Asynchronous DNS: L<AnyEvent::DNS>.
		1849
		1850	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
		1851
1242	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1852	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1243		1853
1244		1854
1245	=head1 AUTHOR	1855	=head1 AUTHOR
1246		1856
1247	Marc Lehmann <schmorp@schmorp.de>	1857	Marc Lehmann <schmorp@schmorp.de>
1248	http://home.schmorp.de/	1858	http://home.schmorp.de/
1249		1859
1250	=cut	1860	=cut
1251		1861
1252	1	1862	1
1253		1863

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