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Revision 1.396 by root, Sat Mar 10 17:36:24 2012 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt,
		6	FLTK and POE are various supported event loops/environments.
6		7
7	=head1 SYNOPSIS	8	=head1 SYNOPSIS
8		9
9	use AnyEvent;	10	use AnyEvent;
10		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
		15	# file handle or descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub {	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
		17
		18	# one-shot or repeating timers
		19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
		20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
		21
		22	print AnyEvent->now; # prints current event loop time
		23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
		24
		25	# POSIX signal
		26	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
		27
		28	# child process exit
		29	my $w = AnyEvent->child (pid => $pid, cb => sub {
		30	my ($pid, $status) = @_;
12	...	31	...
13	});	32	});
14		33
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	34	# called when event loop idle (if applicable)
16	...	35	my $w = AnyEvent->idle (cb => sub { ... });
17	});
18		36
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	37	my $w = AnyEvent->condvar; # stores whether a condition was flagged
20	$w->send; # wake up current and all future recv's	38	$w->send; # wake up current and all future recv's
21	$w->recv; # enters "main loop" till $condvar gets ->send	39	$w->recv; # enters "main loop" till $condvar gets ->send
		40	# use a condvar in callback mode:
		41	$w->cb (sub { $_[0]->recv });
22		42
23	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
24		44
25	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
26	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
27	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
		48
		49	=head1 SUPPORT
		50
		51	An FAQ document is available as L<AnyEvent::FAQ>.
		52
		53	There also is a mailinglist for discussing all things AnyEvent, and an IRC
		54	channel, too.
		55
		56	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		57	Repository>, at L<http://anyevent.schmorp.de>, for more info.
28		58
29	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	59	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
30		60
31	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	61	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
32	nowadays. So what is different about AnyEvent?	62	nowadays. So what is different about AnyEvent?
…		…
48	module users into the same thing by forcing them to use the same event	78	module users into the same thing by forcing them to use the same event
49	model you use.	79	model you use.
50		80
51	For modules like POE or IO::Async (which is a total misnomer as it is	81	For modules like POE or IO::Async (which is a total misnomer as it is
52	actually doing all I/O I<synchronously>...), using them in your module is	82	actually doing all I/O I<synchronously>...), using them in your module is
53	like joining a cult: After you joined, you are dependent on them and you	83	like joining a cult: After you join, you are dependent on them and you
54	cannot use anything else, as they are simply incompatible to everything	84	cannot use anything else, as they are simply incompatible to everything
55	that isn't them. What's worse, all the potential users of your	85	that isn't them. What's worse, all the potential users of your
56	module are I<also> forced to use the same event loop you use.	86	module are I<also> forced to use the same event loop you use.
57		87
58	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	88	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
59	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	89	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
60	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if	90	with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module
61	your module uses one of those, every user of your module has to use it,	91	uses one of those, every user of your module has to use it, too. But if
62	too. But if your module uses AnyEvent, it works transparently with all	92	your module uses AnyEvent, it works transparently with all event models it
63	event models it supports (including stuff like IO::Async, as long as those	93	supports (including stuff like IO::Async, as long as those use one of the
64	use one of the supported event loops. It is trivial to add new event loops	94	supported event loops. It is easy to add new event loops to AnyEvent, too,
65	to AnyEvent, too, so it is future-proof).	95	so it is future-proof).
66		96
67	In addition to being free of having to use I<the one and only true event	97	In addition to being free of having to use I<the one and only true event
68	model>, AnyEvent also is free of bloat and policy: with POE or similar	98	model>, AnyEvent also is free of bloat and policy: with POE or similar
69	modules, you get an enormous amount of code and strict rules you have to	99	modules, you get an enormous amount of code and strict rules you have to
70	follow. AnyEvent, on the other hand, is lean and up to the point, by only	100	follow. AnyEvent, on the other hand, is lean and to the point, by only
71	offering the functionality that is necessary, in as thin as a wrapper as	101	offering the functionality that is necessary, in as thin as a wrapper as
72	technically possible.	102	technically possible.
73		103
74	Of course, AnyEvent comes with a big (and fully optional!) toolbox	104	Of course, AnyEvent comes with a big (and fully optional!) toolbox
75	of useful functionality, such as an asynchronous DNS resolver, 100%	105	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
81	useful) and you want to force your users to use the one and only event	111	useful) and you want to force your users to use the one and only event
82	model, you should I<not> use this module.	112	model, you should I<not> use this module.
83		113
84	=head1 DESCRIPTION	114	=head1 DESCRIPTION
85		115
86	L<AnyEvent> provides an identical interface to multiple event loops. This	116	L<AnyEvent> provides a uniform interface to various event loops. This
87	allows module authors to utilise an event loop without forcing module	117	allows module authors to use event loop functionality without forcing
88	users to use the same event loop (as only a single event loop can coexist	118	module users to use a specific event loop implementation (since more
89	peacefully at any one time).	119	than one event loop cannot coexist peacefully).
90		120
91	The interface itself is vaguely similar, but not identical to the L<Event>	121	The interface itself is vaguely similar, but not identical to the L<Event>
92	module.	122	module.
93		123
94	During the first call of any watcher-creation method, the module tries	124	During the first call of any watcher-creation method, the module tries
95	to detect the currently loaded event loop by probing whether one of the	125	to detect the currently loaded event loop by probing whether one of the
96	following modules is already loaded: L<EV>,	126	following modules is already loaded: L<EV>, L<AnyEvent::Loop>,
97	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	127	L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one
98	L<POE>. The first one found is used. If none are found, the module tries	128	found is used. If none are detected, the module tries to load the first
99	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	129	four modules in the order given; but note that if L<EV> is not
100	adaptor should always succeed) in the order given. The first one that can	130	available, the pure-perl L<AnyEvent::Loop> should always work, so
101	be successfully loaded will be used. If, after this, still none could be	131	the other two are not normally tried.
102	found, AnyEvent will fall back to a pure-perl event loop, which is not
103	very efficient, but should work everywhere.
104		132
105	Because AnyEvent first checks for modules that are already loaded, loading	133	Because AnyEvent first checks for modules that are already loaded, loading
106	an event model explicitly before first using AnyEvent will likely make	134	an event model explicitly before first using AnyEvent will likely make
107	that model the default. For example:	135	that model the default. For example:
108		136
…		…
110	use AnyEvent;	138	use AnyEvent;
111		139
112	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
113		141
114	The I<likely> means that, if any module loads another event model and	142	The I<likely> means that, if any module loads another event model and
115	starts using it, all bets are off. Maybe you should tell their authors to	143	starts using it, all bets are off - this case should be very rare though,
116	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
117		146
118	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called C<AnyEvent::Loop>. Like
119	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	148	other event modules you can load it explicitly and enjoy the high
120	explicitly and enjoy the high availability of that event loop :)	149	availability of that event loop :)
121		150
122	=head1 WATCHERS	151	=head1 WATCHERS
123		152
124	AnyEvent has the central concept of a I<watcher>, which is an object that	153	AnyEvent has the central concept of a I<watcher>, which is an object that
125	stores relevant data for each kind of event you are waiting for, such as	154	stores relevant data for each kind of event you are waiting for, such as
…		…
128	These watchers are normal Perl objects with normal Perl lifetime. After	157	These watchers are normal Perl objects with normal Perl lifetime. After
129	creating a watcher it will immediately "watch" for events and invoke the	158	creating a watcher it will immediately "watch" for events and invoke the
130	callback when the event occurs (of course, only when the event model	159	callback when the event occurs (of course, only when the event model
131	is in control).	160	is in control).
132		161
		162	Note that B<callbacks must not permanently change global variables>
		163	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
		164	callbacks must not C<die> >>. The former is good programming practice in
		165	Perl and the latter stems from the fact that exception handling differs
		166	widely between event loops.
		167
133	To disable the watcher you have to destroy it (e.g. by setting the	168	To disable a watcher you have to destroy it (e.g. by setting the
134	variable you store it in to C<undef> or otherwise deleting all references	169	variable you store it in to C<undef> or otherwise deleting all references
135	to it).	170	to it).
136		171
137	All watchers are created by calling a method on the C<AnyEvent> class.	172	All watchers are created by calling a method on the C<AnyEvent> class.
138		173
139	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
140	example), or need to refer to their watcher object in other ways.	175	example), or need to refer to their watcher object in other ways.
141		176
142	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
143		178
144	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
145	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
146	undef $w;	181	undef $w;
147	});	182	});
…		…
150	my variables are only visible after the statement in which they are	185	my variables are only visible after the statement in which they are
151	declared.	186	declared.
152		187
153	=head2 I/O WATCHERS	188	=head2 I/O WATCHERS
154		189
		190	$w = AnyEvent->io (
		191	fh => <filehandle_or_fileno>,
		192	poll => <"r" or "w">,
		193	cb => <callback>,
		194	);
		195
155	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	196	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
156	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
157		198
158	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events	199	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
159	(AnyEvent might or might not keep a reference to this file handle). C<poll>	200	for events (AnyEvent might or might not keep a reference to this file
		201	handle). Note that only file handles pointing to things for which
		202	non-blocking operation makes sense are allowed. This includes sockets,
		203	most character devices, pipes, fifos and so on, but not for example files
		204	or block devices.
		205
160	must be a string that is either C<r> or C<w>, which creates a watcher	206	C<poll> must be a string that is either C<r> or C<w>, which creates a
161	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the	207	watcher waiting for "r"eadable or "w"ritable events, respectively.
		208
162	callback to invoke each time the file handle becomes ready.	209	C<cb> is the callback to invoke each time the file handle becomes ready.
163		210
164	Although the callback might get passed parameters, their value and	211	Although the callback might get passed parameters, their value and
165	presence is undefined and you cannot rely on them. Portable AnyEvent	212	presence is undefined and you cannot rely on them. Portable AnyEvent
166	callbacks cannot use arguments passed to I/O watcher callbacks.	213	callbacks cannot use arguments passed to I/O watcher callbacks.
167		214
168	The I/O watcher might use the underlying file descriptor or a copy of it.	215	The I/O watcher might use the underlying file descriptor or a copy of it.
169	You must not close a file handle as long as any watcher is active on the	216	You must not close a file handle as long as any watcher is active on the
170	underlying file descriptor.	217	underlying file descriptor.
171		218
172	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
173	always use non-blocking calls when reading/writing from/to your file	220	always use non-blocking calls when reading/writing from/to your file
174	handles.	221	handles.
175		222
176	Example: wait for readability of STDIN, then read a line and disable the	223	Example: wait for readability of STDIN, then read a line and disable the
177	watcher.	224	watcher.
…		…
182	undef $w;	229	undef $w;
183	});	230	});
184		231
185	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
186		233
		234	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		235
		236	$w = AnyEvent->timer (
		237	after => <fractional_seconds>,
		238	interval => <fractional_seconds>,
		239	cb => <callback>,
		240	);
		241
187	You can create a time watcher by calling the C<< AnyEvent->timer >>	242	You can create a time watcher by calling the C<< AnyEvent->timer >>
188	method with the following mandatory arguments:	243	method with the following mandatory arguments:
189		244
190	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
191	supported) the callback should be invoked. C<cb> is the callback to invoke	246	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
193		248
194	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
195	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
196	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
197		252
198	The callback will normally be invoked once only. If you specify another	253	The callback will normally be invoked only once. If you specify another
199	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
200	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
201	seconds) after the first invocation. If C<interval> is specified with a	256	seconds) after the first invocation. If C<interval> is specified with a
202	false value, then it is treated as if it were missing.	257	false value, then it is treated as if it were not specified at all.
203		258
204	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
205	attempt is done to avoid timer drift in most backends, so the interval is	260	attempt is made to avoid timer drift in most backends, so the interval is
206	only approximate.	261	only approximate.
207		262
208	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
209		264
210	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
228		283
229	While most event loops expect timers to specified in a relative way, they	284	While most event loops expect timers to specified in a relative way, they
230	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
231	"jumps", for example, when ntp decides to set your clock backwards from	286	"jumps", for example, when ntp decides to set your clock backwards from
232	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to	287	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to
233	fire "after" a second might actually take six years to finally fire.	288	fire "after a second" might actually take six years to finally fire.
234		289
235	AnyEvent cannot compensate for this. The only event loop that is conscious	290	AnyEvent cannot compensate for this. The only event loop that is conscious
236	about these issues is L<EV>, which offers both relative (ev_timer, based	291	of these issues is L<EV>, which offers both relative (ev_timer, based
237	on true relative time) and absolute (ev_periodic, based on wallclock time)	292	on true relative time) and absolute (ev_periodic, based on wallclock time)
238	timers.	293	timers.
239		294
240	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
241	AnyEvent API.	296	AnyEvent API.
…		…
263	I<In almost all cases (in all cases if you don't care), this is the	318	I<In almost all cases (in all cases if you don't care), this is the
264	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
265		320
266	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
267	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
268	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
269		324
270	The rest of this section is only of relevance if you try to be very exact	325	The rest of this section is only of relevance if you try to be very exact
271	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
272		327
273	For a practical example of when these times differ, consider L<Event::Lib>	328	For a practical example of when these times differ, consider L<Event::Lib>
274	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
275		330
276	The event loop is running and has just invoked one of your callback at	331	The event loop is running and has just invoked one of your callbacks at
277	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
278	you wait a second by executing C<sleep 1> (blocking the process for a	333	you wait a second by executing C<sleep 1> (blocking the process for a
279	second) and then (at time=501) you create a relative timer that fires	334	second) and then (at time=501) you create a relative timer that fires
280	after three seconds.	335	after three seconds.
281		336
…		…
299	In either case, if you care (and in most cases, you don't), then you	354	In either case, if you care (and in most cases, you don't), then you
300	can get whatever behaviour you want with any event loop, by taking the	355	can get whatever behaviour you want with any event loop, by taking the
301	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	356	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
302	account.	357	account.
303		358
		359	=item AnyEvent->now_update
		360
		361	Some event loops (such as L<EV> or L<AnyEvent::Loop>) cache the current
		362	time for each loop iteration (see the discussion of L<< AnyEvent->now >>,
		363	above).
		364
		365	When a callback runs for a long time (or when the process sleeps), then
		366	this "current" time will differ substantially from the real time, which
		367	might affect timers and time-outs.
		368
		369	When this is the case, you can call this method, which will update the
		370	event loop's idea of "current time".
		371
		372	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		373	when mod_perl executes the script, then the event loop will have the wrong
		374	idea about the "current time" (being potentially far in the past, when the
		375	script ran the last time). In that case you should arrange a call to C<<
		376	AnyEvent->now_update >> each time the web server process wakes up again
		377	(e.g. at the start of your script, or in a handler).
		378
		379	Note that updating the time I<might> cause some events to be handled.
		380
304	=back	381	=back
305		382
306	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
307		386
308	You can watch for signals using a signal watcher, C<signal> is the signal	387	You can watch for signals using a signal watcher, C<signal> is the signal
309	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	388	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
310	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
311		390
…		…
317	invocation, and callback invocation will be synchronous. Synchronous means	396	invocation, and callback invocation will be synchronous. Synchronous means
318	that it might take a while until the signal gets handled by the process,	397	that it might take a while until the signal gets handled by the process,
319	but it is guaranteed not to interrupt any other callbacks.	398	but it is guaranteed not to interrupt any other callbacks.
320		399
321	The main advantage of using these watchers is that you can share a signal	400	The main advantage of using these watchers is that you can share a signal
322	between multiple watchers.	401	between multiple watchers, and AnyEvent will ensure that signals will not
		402	interrupt your program at bad times.
323		403
324	This watcher might use C<%SIG>, so programs overwriting those signals	404	This watcher might use C<%SIG> (depending on the event loop used),
325	directly will likely not work correctly.	405	so programs overwriting those signals directly will likely not work
		406	correctly.
326		407
327	Example: exit on SIGINT	408	Example: exit on SIGINT
328		409
329	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
330		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling)
		421	or "unsafe" (asynchronous) - the former might delay signal delivery
		422	indefinitely, the latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
		429	=head3 Signal Races, Delays and Workarounds
		430
		431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support
		432	attaching callbacks to signals in a generic way, which is a pity,
		433	as you cannot do race-free signal handling in perl, requiring
		434	C libraries for this. AnyEvent will try to do its best, which
		435	means in some cases, signals will be delayed. The maximum time
		436	a signal might be delayed is 10 seconds by default, but can
		437	be overriden via C<$ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY}> or
		438	C<$AnyEvent::MAX_SIGNAL_LATENCY> - see the L<ENVIRONMENT VARIABLES>
		439	section for details.
		440
		441	All these problems can be avoided by installing the optional
		442	L<Async::Interrupt> module, which works with most event loops. It will not
		443	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		444	(and not with L<POE> currently). For those, you just have to suffer the
		445	delays.
		446
331	=head2 CHILD PROCESS WATCHERS	447	=head2 CHILD PROCESS WATCHERS
332		448
		449	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		450
333	You can also watch on a child process exit and catch its exit status.	451	You can also watch for a child process exit and catch its exit status.
334		452
335	The child process is specified by the C<pid> argument (if set to C<0>, it	453	The child process is specified by the C<pid> argument (on some backends,
336	watches for any child process exit). The watcher will trigger as often	454	using C<0> watches for any child process exit, on others this will
337	as status change for the child are received. This works by installing a	455	croak). The watcher will be triggered only when the child process has
338	signal handler for C<SIGCHLD>. The callback will be called with the pid	456	finished and an exit status is available, not on any trace events
339	and exit status (as returned by waitpid), so unlike other watcher types,	457	(stopped/continued).
340	you I<can> rely on child watcher callback arguments.	458
		459	The callback will be called with the pid and exit status (as returned by
		460	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		461	callback arguments.
		462
		463	This watcher type works by installing a signal handler for C<SIGCHLD>,
		464	and since it cannot be shared, nothing else should use SIGCHLD or reap
		465	random child processes (waiting for specific child processes, e.g. inside
		466	C<system>, is just fine).
341		467
342	There is a slight catch to child watchers, however: you usually start them	468	There is a slight catch to child watchers, however: you usually start them
343	I<after> the child process was created, and this means the process could	469	I<after> the child process was created, and this means the process could
344	have exited already (and no SIGCHLD will be sent anymore).	470	have exited already (and no SIGCHLD will be sent anymore).
345		471
346	Not all event models handle this correctly (POE doesn't), but even for	472	Not all event models handle this correctly (neither POE nor IO::Async do,
		473	see their AnyEvent::Impl manpages for details), but even for event models
347	event models that I<do> handle this correctly, they usually need to be	474	that I<do> handle this correctly, they usually need to be loaded before
348	loaded before the process exits (i.e. before you fork in the first place).	475	the process exits (i.e. before you fork in the first place). AnyEvent's
		476	pure perl event loop handles all cases correctly regardless of when you
		477	start the watcher.
349		478
350	This means you cannot create a child watcher as the very first thing in an	479	This means you cannot create a child watcher as the very first
351	AnyEvent program, you I<have> to create at least one watcher before you	480	thing in an AnyEvent program, you I<have> to create at least one
352	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	481	watcher before you C<fork> the child (alternatively, you can call
		482	C<AnyEvent::detect>).
		483
		484	As most event loops do not support waiting for child events, they will be
		485	emulated by AnyEvent in most cases, in which case the latency and race
		486	problems mentioned in the description of signal watchers apply.
353		487
354	Example: fork a process and wait for it	488	Example: fork a process and wait for it
355		489
356	my $done = AnyEvent->condvar;	490	my $done = AnyEvent->condvar;
357		491
…		…
367	);	501	);
368		502
369	# do something else, then wait for process exit	503	# do something else, then wait for process exit
370	$done->recv;	504	$done->recv;
371		505
		506	=head2 IDLE WATCHERS
		507
		508	$w = AnyEvent->idle (cb => <callback>);
		509
		510	This will repeatedly invoke the callback after the process becomes idle,
		511	until either the watcher is destroyed or new events have been detected.
		512
		513	Idle watchers are useful when there is a need to do something, but it
		514	is not so important (or wise) to do it instantly. The callback will be
		515	invoked only when there is "nothing better to do", which is usually
		516	defined as "all outstanding events have been handled and no new events
		517	have been detected". That means that idle watchers ideally get invoked
		518	when the event loop has just polled for new events but none have been
		519	detected. Instead of blocking to wait for more events, the idle watchers
		520	will be invoked.
		521
		522	Unfortunately, most event loops do not really support idle watchers (only
		523	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		524	will simply call the callback "from time to time".
		525
		526	Example: read lines from STDIN, but only process them when the
		527	program is otherwise idle:
		528
		529	my @lines; # read data
		530	my $idle_w;
		531	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		532	push @lines, scalar <STDIN>;
		533
		534	# start an idle watcher, if not already done
		535	$idle_w ||= AnyEvent->idle (cb => sub {
		536	# handle only one line, when there are lines left
		537	if (my $line = shift @lines) {
		538	print "handled when idle: $line";
		539	} else {
		540	# otherwise disable the idle watcher again
		541	undef $idle_w;
		542	}
		543	});
		544	});
		545
372	=head2 CONDITION VARIABLES	546	=head2 CONDITION VARIABLES
		547
		548	$cv = AnyEvent->condvar;
		549
		550	$cv->send (<list>);
		551	my @res = $cv->recv;
373		552
374	If you are familiar with some event loops you will know that all of them	553	If you are familiar with some event loops you will know that all of them
375	require you to run some blocking "loop", "run" or similar function that	554	require you to run some blocking "loop", "run" or similar function that
376	will actively watch for new events and call your callbacks.	555	will actively watch for new events and call your callbacks.
377		556
378	AnyEvent is different, it expects somebody else to run the event loop and	557	AnyEvent is slightly different: it expects somebody else to run the event
379	will only block when necessary (usually when told by the user).	558	loop and will only block when necessary (usually when told by the user).
380		559
381	The instrument to do that is called a "condition variable", so called	560	The tool to do that is called a "condition variable", so called because
382	because they represent a condition that must become true.	561	they represent a condition that must become true.
		562
		563	Now is probably a good time to look at the examples further below.
383		564
384	Condition variables can be created by calling the C<< AnyEvent->condvar	565	Condition variables can be created by calling the C<< AnyEvent->condvar
385	>> method, usually without arguments. The only argument pair allowed is	566	>> method, usually without arguments. The only argument pair allowed is
386	C<cb>, which specifies a callback to be called when the condition variable	567	C<cb>, which specifies a callback to be called when the condition variable
387	becomes true.	568	becomes true, with the condition variable as the first argument (but not
		569	the results).
388		570
389	After creation, the condition variable is "false" until it becomes "true"	571	After creation, the condition variable is "false" until it becomes "true"
390	by calling the C<send> method (or calling the condition variable as if it	572	by calling the C<send> method (or calling the condition variable as if it
391	were a callback, read about the caveats in the description for the C<<	573	were a callback, read about the caveats in the description for the C<<
392	->send >> method).	574	->send >> method).
393		575
394	Condition variables are similar to callbacks, except that you can	576	Since condition variables are the most complex part of the AnyEvent API, here are
395	optionally wait for them. They can also be called merge points - points	577	some different mental models of what they are - pick the ones you can connect to:
396	in time where multiple outstanding events have been processed. And yet	578
397	another way to call them is transactions - each condition variable can be	579	=over 4
398	used to represent a transaction, which finishes at some point and delivers	580
399	a result.	581	=item * Condition variables are like callbacks - you can call them (and pass them instead
		582	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		583
		584	=item * Condition variables are signals - one side can emit or send them,
		585	the other side can wait for them, or install a handler that is called when
		586	the signal fires.
		587
		588	=item * Condition variables are like "Merge Points" - points in your program
		589	where you merge multiple independent results/control flows into one.
		590
		591	=item * Condition variables represent a transaction - functions that start
		592	some kind of transaction can return them, leaving the caller the choice
		593	between waiting in a blocking fashion, or setting a callback.
		594
		595	=item * Condition variables represent future values, or promises to deliver
		596	some result, long before the result is available.
		597
		598	=back
400		599
401	Condition variables are very useful to signal that something has finished,	600	Condition variables are very useful to signal that something has finished,
402	for example, if you write a module that does asynchronous http requests,	601	for example, if you write a module that does asynchronous http requests,
403	then a condition variable would be the ideal candidate to signal the	602	then a condition variable would be the ideal candidate to signal the
404	availability of results. The user can either act when the callback is	603	availability of results. The user can either act when the callback is
…		…
417		616
418	Condition variables are represented by hash refs in perl, and the keys	617	Condition variables are represented by hash refs in perl, and the keys
419	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing	618	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
420	easy (it is often useful to build your own transaction class on top of	619	easy (it is often useful to build your own transaction class on top of
421	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call	620	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
422	it's C<new> method in your own C<new> method.	621	its C<new> method in your own C<new> method.
423		622
424	There are two "sides" to a condition variable - the "producer side" which	623	There are two "sides" to a condition variable - the "producer side" which
425	eventually calls C<< -> send >>, and the "consumer side", which waits	624	eventually calls C<< -> send >>, and the "consumer side", which waits
426	for the send to occur.	625	for the send to occur.
427		626
428	Example: wait for a timer.	627	Example: wait for a timer.
429		628
430	# wait till the result is ready	629	# condition: "wait till the timer is fired"
431	my $result_ready = AnyEvent->condvar;	630	my $timer_fired = AnyEvent->condvar;
432		631
433	# do something such as adding a timer	632	# create the timer - we could wait for, say
434	# or socket watcher the calls $result_ready->send	633	# a handle becomign ready, or even an
435	# when the "result" is ready.	634	# AnyEvent::HTTP request to finish, but
436	# in this case, we simply use a timer:	635	# in this case, we simply use a timer:
437	my $w = AnyEvent->timer (	636	my $w = AnyEvent->timer (
438	after => 1,	637	after => 1,
439	cb => sub { $result_ready->send },	638	cb => sub { $timer_fired->send },
440	);	639	);
441		640
442	# this "blocks" (while handling events) till the callback	641	# this "blocks" (while handling events) till the callback
443	# calls send	642	# calls ->send
444	$result_ready->recv;	643	$timer_fired->recv;
445		644
446	Example: wait for a timer, but take advantage of the fact that	645	Example: wait for a timer, but take advantage of the fact that condition
447	condition variables are also code references.	646	variables are also callable directly.
448		647
449	my $done = AnyEvent->condvar;	648	my $done = AnyEvent->condvar;
450	my $delay = AnyEvent->timer (after => 5, cb => $done);	649	my $delay = AnyEvent->timer (after => 5, cb => $done);
451	$done->recv;	650	$done->recv;
		651
		652	Example: Imagine an API that returns a condvar and doesn't support
		653	callbacks. This is how you make a synchronous call, for example from
		654	the main program:
		655
		656	use AnyEvent::CouchDB;
		657
		658	...
		659
		660	my @info = $couchdb->info->recv;
		661
		662	And this is how you would just set a callback to be called whenever the
		663	results are available:
		664
		665	$couchdb->info->cb (sub {
		666	my @info = $_[0]->recv;
		667	});
452		668
453	=head3 METHODS FOR PRODUCERS	669	=head3 METHODS FOR PRODUCERS
454		670
455	These methods should only be used by the producing side, i.e. the	671	These methods should only be used by the producing side, i.e. the
456	code/module that eventually sends the signal. Note that it is also	672	code/module that eventually sends the signal. Note that it is also
…		…
469	immediately from within send.	685	immediately from within send.
470		686
471	Any arguments passed to the C<send> call will be returned by all	687	Any arguments passed to the C<send> call will be returned by all
472	future C<< ->recv >> calls.	688	future C<< ->recv >> calls.
473		689
474	Condition variables are overloaded so one can call them directly	690	Condition variables are overloaded so one can call them directly (as if
475	(as a code reference). Calling them directly is the same as calling	691	they were a code reference). Calling them directly is the same as calling
476	C<send>. Note, however, that many C-based event loops do not handle	692	C<send>.
477	overloading, so as tempting as it may be, passing a condition variable
478	instead of a callback does not work. Both the pure perl and EV loops
479	support overloading, however, as well as all functions that use perl to
480	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
481	example).
482		693
483	=item $cv->croak ($error)	694	=item $cv->croak ($error)
484		695
485	Similar to send, but causes all call's to C<< ->recv >> to invoke	696	Similar to send, but causes all calls to C<< ->recv >> to invoke
486	C<Carp::croak> with the given error message/object/scalar.	697	C<Carp::croak> with the given error message/object/scalar.
487		698
488	This can be used to signal any errors to the condition variable	699	This can be used to signal any errors to the condition variable
489	user/consumer.	700	user/consumer. Doing it this way instead of calling C<croak> directly
		701	delays the error detection, but has the overwhelming advantage that it
		702	diagnoses the error at the place where the result is expected, and not
		703	deep in some event callback with no connection to the actual code causing
		704	the problem.
490		705
491	=item $cv->begin ([group callback])	706	=item $cv->begin ([group callback])
492		707
493	=item $cv->end	708	=item $cv->end
494
495	These two methods are EXPERIMENTAL and MIGHT CHANGE.
496		709
497	These two methods can be used to combine many transactions/events into	710	These two methods can be used to combine many transactions/events into
498	one. For example, a function that pings many hosts in parallel might want	711	one. For example, a function that pings many hosts in parallel might want
499	to use a condition variable for the whole process.	712	to use a condition variable for the whole process.
500		713
501	Every call to C<< ->begin >> will increment a counter, and every call to	714	Every call to C<< ->begin >> will increment a counter, and every call to
502	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	715	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
503	>>, the (last) callback passed to C<begin> will be executed. That callback	716	>>, the (last) callback passed to C<begin> will be executed, passing the
504	is I<supposed> to call C<< ->send >>, but that is not required. If no	717	condvar as first argument. That callback is I<supposed> to call C<< ->send
505	callback was set, C<send> will be called without any arguments.	718	>>, but that is not required. If no group callback was set, C<send> will
		719	be called without any arguments.
506		720
507	Let's clarify this with the ping example:	721	You can think of C<< $cv->send >> giving you an OR condition (one call
		722	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		723	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		724
		725	Let's start with a simple example: you have two I/O watchers (for example,
		726	STDOUT and STDERR for a program), and you want to wait for both streams to
		727	close before activating a condvar:
508		728
509	my $cv = AnyEvent->condvar;	729	my $cv = AnyEvent->condvar;
510		730
		731	$cv->begin; # first watcher
		732	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		733	defined sysread $fh1, my $buf, 4096
		734	or $cv->end;
		735	});
		736
		737	$cv->begin; # second watcher
		738	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		739	defined sysread $fh2, my $buf, 4096
		740	or $cv->end;
		741	});
		742
		743	$cv->recv;
		744
		745	This works because for every event source (EOF on file handle), there is
		746	one call to C<begin>, so the condvar waits for all calls to C<end> before
		747	sending.
		748
		749	The ping example mentioned above is slightly more complicated, as the
		750	there are results to be passwd back, and the number of tasks that are
		751	begun can potentially be zero:
		752
		753	my $cv = AnyEvent->condvar;
		754
511	my %result;	755	my %result;
512	$cv->begin (sub { $cv->send (\%result) });	756	$cv->begin (sub { shift->send (\%result) });
513		757
514	for my $host (@list_of_hosts) {	758	for my $host (@list_of_hosts) {
515	$cv->begin;	759	$cv->begin;
516	ping_host_then_call_callback $host, sub {	760	ping_host_then_call_callback $host, sub {
517	$result{$host} = ...;	761	$result{$host} = ...;
…		…
532	loop, which serves two important purposes: first, it sets the callback	776	loop, which serves two important purposes: first, it sets the callback
533	to be called once the counter reaches C<0>, and second, it ensures that	777	to be called once the counter reaches C<0>, and second, it ensures that
534	C<send> is called even when C<no> hosts are being pinged (the loop	778	C<send> is called even when C<no> hosts are being pinged (the loop
535	doesn't execute once).	779	doesn't execute once).
536		780
537	This is the general pattern when you "fan out" into multiple subrequests:	781	This is the general pattern when you "fan out" into multiple (but
538	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	782	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
539	is called at least once, and then, for each subrequest you start, call	783	the callback and ensure C<end> is called at least once, and then, for each
540	C<begin> and for each subrequest you finish, call C<end>.	784	subrequest you start, call C<begin> and for each subrequest you finish,
		785	call C<end>.
541		786
542	=back	787	=back
543		788
544	=head3 METHODS FOR CONSUMERS	789	=head3 METHODS FOR CONSUMERS
545		790
…		…
549	=over 4	794	=over 4
550		795
551	=item $cv->recv	796	=item $cv->recv
552		797
553	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	798	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
554	>> methods have been called on c<$cv>, while servicing other watchers	799	>> methods have been called on C<$cv>, while servicing other watchers
555	normally.	800	normally.
556		801
557	You can only wait once on a condition - additional calls are valid but	802	You can only wait once on a condition - additional calls are valid but
558	will return immediately.	803	will return immediately.
559		804
…		…
561	function will call C<croak>.	806	function will call C<croak>.
562		807
563	In list context, all parameters passed to C<send> will be returned,	808	In list context, all parameters passed to C<send> will be returned,
564	in scalar context only the first one will be returned.	809	in scalar context only the first one will be returned.
565		810
		811	Note that doing a blocking wait in a callback is not supported by any
		812	event loop, that is, recursive invocation of a blocking C<< ->recv
		813	>> is not allowed, and the C<recv> call will C<croak> if such a
		814	condition is detected. This condition can be slightly loosened by using
		815	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		816	any thread that doesn't run the event loop itself.
		817
566	Not all event models support a blocking wait - some die in that case	818	Not all event models support a blocking wait - some die in that case
567	(programs might want to do that to stay interactive), so I<if you are	819	(programs might want to do that to stay interactive), so I<if you are
568	using this from a module, never require a blocking wait>, but let the	820	using this from a module, never require a blocking wait>. Instead, let the
569	caller decide whether the call will block or not (for example, by coupling	821	caller decide whether the call will block or not (for example, by coupling
570	condition variables with some kind of request results and supporting	822	condition variables with some kind of request results and supporting
571	callbacks so the caller knows that getting the result will not block,	823	callbacks so the caller knows that getting the result will not block,
572	while still supporting blocking waits if the caller so desires).	824	while still supporting blocking waits if the caller so desires).
573		825
574	Another reason I<never> to C<< ->recv >> in a module is that you cannot
575	sensibly have two C<< ->recv >>'s in parallel, as that would require
576	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
577	can supply.
578
579	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
580	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
581	versions and also integrates coroutines into AnyEvent, making blocking
582	C<< ->recv >> calls perfectly safe as long as they are done from another
583	coroutine (one that doesn't run the event loop).
584
585	You can ensure that C<< -recv >> never blocks by setting a callback and	826	You can ensure that C<< ->recv >> never blocks by setting a callback and
586	only calling C<< ->recv >> from within that callback (or at a later	827	only calling C<< ->recv >> from within that callback (or at a later
587	time). This will work even when the event loop does not support blocking	828	time). This will work even when the event loop does not support blocking
588	waits otherwise.	829	waits otherwise.
589		830
590	=item $bool = $cv->ready	831	=item $bool = $cv->ready
591		832
592	Returns true when the condition is "true", i.e. whether C<send> or	833	Returns true when the condition is "true", i.e. whether C<send> or
593	C<croak> have been called.	834	C<croak> have been called.
594		835
595	=item $cb = $cv->cb ([new callback])	836	=item $cb = $cv->cb ($cb->($cv))
596		837
597	This is a mutator function that returns the callback set and optionally	838	This is a mutator function that returns the callback set and optionally
598	replaces it before doing so.	839	replaces it before doing so.
599		840
600	The callback will be called when the condition becomes "true", i.e. when	841	The callback will be called when the condition becomes "true", i.e. when
601	C<send> or C<croak> are called, with the only argument being the condition	842	C<send> or C<croak> are called, with the only argument being the
602	variable itself. Calling C<recv> inside the callback or at any later time	843	condition variable itself. If the condition is already true, the
603	is guaranteed not to block.	844	callback is called immediately when it is set. Calling C<recv> inside
		845	the callback or at any later time is guaranteed not to block.
604		846
605	=back	847	=back
606		848
		849	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		850
		851	The available backend classes are (every class has its own manpage):
		852
		853	=over 4
		854
		855	=item Backends that are autoprobed when no other event loop can be found.
		856
		857	EV is the preferred backend when no other event loop seems to be in
		858	use. If EV is not installed, then AnyEvent will fall back to its own
		859	pure-perl implementation, which is available everywhere as it comes with
		860	AnyEvent itself.
		861
		862	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		863	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
		864
		865	=item Backends that are transparently being picked up when they are used.
		866
		867	These will be used if they are already loaded when the first watcher
		868	is created, in which case it is assumed that the application is using
		869	them. This means that AnyEvent will automatically pick the right backend
		870	when the main program loads an event module before anything starts to
		871	create watchers. Nothing special needs to be done by the main program.
		872
		873	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		874	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		875	AnyEvent::Impl::Tk based on Tk, very broken.
		876	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		877	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		878	AnyEvent::Impl::Irssi used when running within irssi.
		879	AnyEvent::Impl::IOAsync based on IO::Async.
		880	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
		881	AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding).
		882
		883	=item Backends with special needs.
		884
		885	Qt requires the Qt::Application to be instantiated first, but will
		886	otherwise be picked up automatically. As long as the main program
		887	instantiates the application before any AnyEvent watchers are created,
		888	everything should just work.
		889
		890	AnyEvent::Impl::Qt based on Qt.
		891
		892	=item Event loops that are indirectly supported via other backends.
		893
		894	Some event loops can be supported via other modules:
		895
		896	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		897
		898	B<WxWidgets> has no support for watching file handles. However, you can
		899	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		900	polls 20 times per second, which was considered to be too horrible to even
		901	consider for AnyEvent.
		902
		903	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		904	backend, so it can be supported through POE.
		905
		906	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		907	load L<POE> when detecting them, in the hope that POE will pick them up,
		908	in which case everything will be automatic.
		909
		910	=back
		911
607	=head1 GLOBAL VARIABLES AND FUNCTIONS	912	=head1 GLOBAL VARIABLES AND FUNCTIONS
608		913
		914	These are not normally required to use AnyEvent, but can be useful to
		915	write AnyEvent extension modules.
		916
609	=over 4	917	=over 4
610		918
611	=item $AnyEvent::MODEL	919	=item $AnyEvent::MODEL
612		920
613	Contains C<undef> until the first watcher is being created. Then it	921	Contains C<undef> until the first watcher is being created, before the
		922	backend has been autodetected.
		923
614	contains the event model that is being used, which is the name of the	924	Afterwards it contains the event model that is being used, which is the
615	Perl class implementing the model. This class is usually one of the	925	name of the Perl class implementing the model. This class is usually one
616	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	926	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
617	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	927	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
618		928	will be C<urxvt::anyevent>).
619	The known classes so far are:
620
621	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
622	AnyEvent::Impl::Event based on Event, second best choice.
623	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
624	AnyEvent::Impl::Glib based on Glib, third-best choice.
625	AnyEvent::Impl::Tk based on Tk, very bad choice.
626	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
627	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
628	AnyEvent::Impl::POE based on POE, not generic enough for full support.
629
630	There is no support for WxWidgets, as WxWidgets has no support for
631	watching file handles. However, you can use WxWidgets through the
632	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
633	second, which was considered to be too horrible to even consider for
634	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
635	it's adaptor.
636
637	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
638	autodetecting them.
639		929
640	=item AnyEvent::detect	930	=item AnyEvent::detect
641		931
642	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	932	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
643	if necessary. You should only call this function right before you would	933	if necessary. You should only call this function right before you would
644	have created an AnyEvent watcher anyway, that is, as late as possible at	934	have created an AnyEvent watcher anyway, that is, as late as possible at
645	runtime.	935	runtime, and not e.g. during initialisation of your module.
		936
		937	The effect of calling this function is as if a watcher had been created
		938	(specifically, actions that happen "when the first watcher is created"
		939	happen when calling detetc as well).
		940
		941	If you need to do some initialisation before AnyEvent watchers are
		942	created, use C<post_detect>.
646		943
647	=item $guard = AnyEvent::post_detect { BLOCK }	944	=item $guard = AnyEvent::post_detect { BLOCK }
648		945
649	Arranges for the code block to be executed as soon as the event model is	946	Arranges for the code block to be executed as soon as the event model is
650	autodetected (or immediately if this has already happened).	947	autodetected (or immediately if that has already happened).
		948
		949	The block will be executed I<after> the actual backend has been detected
		950	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		951	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		952	other initialisations - see the sources of L<AnyEvent::Strict> or
		953	L<AnyEvent::AIO> to see how this is used.
		954
		955	The most common usage is to create some global watchers, without forcing
		956	event module detection too early, for example, L<AnyEvent::AIO> creates
		957	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		958	avoid autodetecting the event module at load time.
651		959
652	If called in scalar or list context, then it creates and returns an object	960	If called in scalar or list context, then it creates and returns an object
653	that automatically removes the callback again when it is destroyed. See	961	that automatically removes the callback again when it is destroyed (or
		962	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
654	L<Coro::BDB> for a case where this is useful.	963	a case where this is useful.
		964
		965	Example: Create a watcher for the IO::AIO module and store it in
		966	C<$WATCHER>, but do so only do so after the event loop is initialised.
		967
		968	our WATCHER;
		969
		970	my $guard = AnyEvent::post_detect {
		971	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		972	};
		973
		974	# the ||= is important in case post_detect immediately runs the block,
		975	# as to not clobber the newly-created watcher. assigning both watcher and
		976	# post_detect guard to the same variable has the advantage of users being
		977	# able to just C<undef $WATCHER> if the watcher causes them grief.
		978
		979	$WATCHER ||= $guard;
655		980
656	=item @AnyEvent::post_detect	981	=item @AnyEvent::post_detect
657		982
658	If there are any code references in this array (you can C<push> to it	983	If there are any code references in this array (you can C<push> to it
659	before or after loading AnyEvent), then they will called directly after	984	before or after loading AnyEvent), then they will be called directly
660	the event loop has been chosen.	985	after the event loop has been chosen.
661		986
662	You should check C<$AnyEvent::MODEL> before adding to this array, though:	987	You should check C<$AnyEvent::MODEL> before adding to this array, though:
663	if it contains a true value then the event loop has already been detected,	988	if it is defined then the event loop has already been detected, and the
664	and the array will be ignored.	989	array will be ignored.
665		990
666	Best use C<AnyEvent::post_detect { BLOCK }> instead.	991	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		992	it, as it takes care of these details.
		993
		994	This variable is mainly useful for modules that can do something useful
		995	when AnyEvent is used and thus want to know when it is initialised, but do
		996	not need to even load it by default. This array provides the means to hook
		997	into AnyEvent passively, without loading it.
		998
		999	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1000	together, you could put this into Coro (this is the actual code used by
		1001	Coro to accomplish this):
		1002
		1003	if (defined $AnyEvent::MODEL) {
		1004	# AnyEvent already initialised, so load Coro::AnyEvent
		1005	require Coro::AnyEvent;
		1006	} else {
		1007	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1008	# as soon as it is
		1009	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1010	}
		1011
		1012	=item AnyEvent::postpone { BLOCK }
		1013
		1014	Arranges for the block to be executed as soon as possible, but not before
		1015	the call itself returns. In practise, the block will be executed just
		1016	before the event loop polls for new events, or shortly afterwards.
		1017
		1018	This function never returns anything (to make the C<return postpone { ...
		1019	}> idiom more useful.
		1020
		1021	To understand the usefulness of this function, consider a function that
		1022	asynchronously does something for you and returns some transaction
		1023	object or guard to let you cancel the operation. For example,
		1024	C<AnyEvent::Socket::tcp_connect>:
		1025
		1026	# start a conenction attempt unless one is active
		1027	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1028	delete $self->{connect_guard};
		1029	...
		1030	};
		1031
		1032	Imagine that this function could instantly call the callback, for
		1033	example, because it detects an obvious error such as a negative port
		1034	number. Invoking the callback before the function returns causes problems
		1035	however: the callback will be called and will try to delete the guard
		1036	object. But since the function hasn't returned yet, there is nothing to
		1037	delete. When the function eventually returns it will assign the guard
		1038	object to C<< $self->{connect_guard} >>, where it will likely never be
		1039	deleted, so the program thinks it is still trying to connect.
		1040
		1041	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1042	callback directly on error:
		1043
		1044	$cb->(undef), return # signal error to callback, BAD!
		1045	if $some_error_condition;
		1046
		1047	It should use C<postpone>:
		1048
		1049	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1050	if $some_error_condition;
		1051
		1052	=item AnyEvent::log $level, $msg[, @args]
		1053
		1054	Log the given C<$msg> at the given C<$level>.
		1055
		1056	If L<AnyEvent::Log> is not loaded then this function makes a simple test
		1057	to see whether the message will be logged. If the test succeeds it will
		1058	load AnyEvent::Log and call C<AnyEvent::Log::log> - consequently, look at
		1059	the L<AnyEvent::Log> documentation for details.
		1060
		1061	If the test fails it will simply return. Right now this happens when a
		1062	numerical loglevel is used and it is larger than the level specified via
		1063	C<$ENV{PERL_ANYEVENT_VERBOSE}>.
		1064
		1065	If you want to sprinkle loads of logging calls around your code, consider
		1066	creating a logger callback with the C<AnyEvent::Log::logger> function,
		1067	which can reduce typing, codesize and can reduce the logging overhead
		1068	enourmously.
667		1069
668	=back	1070	=back
669		1071
670	=head1 WHAT TO DO IN A MODULE	1072	=head1 WHAT TO DO IN A MODULE
671		1073
…		…
682	because it will stall the whole program, and the whole point of using	1084	because it will stall the whole program, and the whole point of using
683	events is to stay interactive.	1085	events is to stay interactive.
684		1086
685	It is fine, however, to call C<< ->recv >> when the user of your module	1087	It is fine, however, to call C<< ->recv >> when the user of your module
686	requests it (i.e. if you create a http request object ad have a method	1088	requests it (i.e. if you create a http request object ad have a method
687	called C<results> that returns the results, it should call C<< ->recv >>	1089	called C<results> that returns the results, it may call C<< ->recv >>
688	freely, as the user of your module knows what she is doing. always).	1090	freely, as the user of your module knows what she is doing. Always).
689		1091
690	=head1 WHAT TO DO IN THE MAIN PROGRAM	1092	=head1 WHAT TO DO IN THE MAIN PROGRAM
691		1093
692	There will always be a single main program - the only place that should	1094	There will always be a single main program - the only place that should
693	dictate which event model to use.	1095	dictate which event model to use.
694		1096
695	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1097	If the program is not event-based, it need not do anything special, even
696	do anything special (it does not need to be event-based) and let AnyEvent	1098	when it depends on a module that uses an AnyEvent. If the program itself
697	decide which implementation to chose if some module relies on it.	1099	uses AnyEvent, but does not care which event loop is used, all it needs
		1100	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1101	available loop implementation.
698		1102
699	If the main program relies on a specific event model - for example, in	1103	If the main program relies on a specific event model - for example, in
700	Gtk2 programs you have to rely on the Glib module - you should load the	1104	Gtk2 programs you have to rely on the Glib module - you should load the
701	event module before loading AnyEvent or any module that uses it: generally	1105	event module before loading AnyEvent or any module that uses it: generally
702	speaking, you should load it as early as possible. The reason is that	1106	speaking, you should load it as early as possible. The reason is that
703	modules might create watchers when they are loaded, and AnyEvent will	1107	modules might create watchers when they are loaded, and AnyEvent will
704	decide on the event model to use as soon as it creates watchers, and it	1108	decide on the event model to use as soon as it creates watchers, and it
705	might chose the wrong one unless you load the correct one yourself.	1109	might choose the wrong one unless you load the correct one yourself.
706		1110
707	You can chose to use a pure-perl implementation by loading the	1111	You can chose to use a pure-perl implementation by loading the
708	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1112	C<AnyEvent::Loop> module, which gives you similar behaviour
709	everywhere, but letting AnyEvent chose the model is generally better.	1113	everywhere, but letting AnyEvent chose the model is generally better.
710		1114
711	=head2 MAINLOOP EMULATION	1115	=head2 MAINLOOP EMULATION
712		1116
713	Sometimes (often for short test scripts, or even standalone programs who	1117	Sometimes (often for short test scripts, or even standalone programs who
…		…
726		1130
727		1131
728	=head1 OTHER MODULES	1132	=head1 OTHER MODULES
729		1133
730	The following is a non-exhaustive list of additional modules that use	1134	The following is a non-exhaustive list of additional modules that use
731	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1135	AnyEvent as a client and can therefore be mixed easily with other
732	in the same program. Some of the modules come with AnyEvent, some are	1136	AnyEvent modules and other event loops in the same program. Some of the
733	available via CPAN.	1137	modules come as part of AnyEvent, the others are available via CPAN (see
		1138	L<http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for
		1139	a longer non-exhaustive list), and the list is heavily biased towards
		1140	modules of the AnyEvent author himself :)
734		1141
735	=over 4	1142	=over 4
736		1143
737	=item L<AnyEvent::Util>	1144	=item L<AnyEvent::Util>
738		1145
739	Contains various utility functions that replace often-used but blocking	1146	Contains various utility functions that replace often-used blocking
740	functions such as C<inet_aton> by event-/callback-based versions.	1147	functions such as C<inet_aton> with event/callback-based versions.
741		1148
742	=item L<AnyEvent::Socket>	1149	=item L<AnyEvent::Socket>
743		1150
744	Provides various utility functions for (internet protocol) sockets,	1151	Provides various utility functions for (internet protocol) sockets,
745	addresses and name resolution. Also functions to create non-blocking tcp	1152	addresses and name resolution. Also functions to create non-blocking tcp
…		…
747		1154
748	=item L<AnyEvent::Handle>	1155	=item L<AnyEvent::Handle>
749		1156
750	Provide read and write buffers, manages watchers for reads and writes,	1157	Provide read and write buffers, manages watchers for reads and writes,
751	supports raw and formatted I/O, I/O queued and fully transparent and	1158	supports raw and formatted I/O, I/O queued and fully transparent and
752	non-blocking SSL/TLS.	1159	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
753		1160
754	=item L<AnyEvent::DNS>	1161	=item L<AnyEvent::DNS>
755		1162
756	Provides rich asynchronous DNS resolver capabilities.	1163	Provides rich asynchronous DNS resolver capabilities.
757		1164
		1165	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1166
		1167	Implement event-based interfaces to the protocols of the same name (for
		1168	the curious, IGS is the International Go Server and FCP is the Freenet
		1169	Client Protocol).
		1170
758	=item L<AnyEvent::HTTP>	1171	=item L<AnyEvent::AIO>
759		1172
760	A simple-to-use HTTP library that is capable of making a lot of concurrent	1173	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
761	HTTP requests.	1174	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1175	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1176	file I/O, and much more.
		1177
		1178	=item L<AnyEvent::Filesys::Notify>
		1179
		1180	AnyEvent is good for non-blocking stuff, but it can't detect file or
		1181	path changes (e.g. "watch this directory for new files", "watch this
		1182	file for changes"). The L<AnyEvent::Filesys::Notify> module promises to
		1183	do just that in a portbale fashion, supporting inotify on GNU/Linux and
		1184	some weird, without doubt broken, stuff on OS X to monitor files. It can
		1185	fall back to blocking scans at regular intervals transparently on other
		1186	platforms, so it's about as portable as it gets.
		1187
		1188	(I haven't used it myself, but I haven't heard anybody complaining about
		1189	it yet).
		1190
		1191	=item L<AnyEvent::DBI>
		1192
		1193	Executes L<DBI> requests asynchronously in a proxy process for you,
		1194	notifying you in an event-based way when the operation is finished.
762		1195
763	=item L<AnyEvent::HTTPD>	1196	=item L<AnyEvent::HTTPD>
764		1197
765	Provides a simple web application server framework.	1198	A simple embedded webserver.
766		1199
767	=item L<AnyEvent::FastPing>	1200	=item L<AnyEvent::FastPing>
768		1201
769	The fastest ping in the west.	1202	The fastest ping in the west.
770		1203
771	=item L<AnyEvent::DBI>
772
773	Executes L<DBI> requests asynchronously in a proxy process.
774
775	=item L<AnyEvent::AIO>
776
777	Truly asynchronous I/O, should be in the toolbox of every event
778	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
779	together.
780
781	=item L<AnyEvent::BDB>
782
783	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
784	L<BDB> and AnyEvent together.
785
786	=item L<AnyEvent::GPSD>
787
788	A non-blocking interface to gpsd, a daemon delivering GPS information.
789
790	=item L<AnyEvent::IGS>
791
792	A non-blocking interface to the Internet Go Server protocol (used by
793	L<App::IGS>).
794
795	=item L<Net::IRC3>
796
797	AnyEvent based IRC client module family.
798
799	=item L<Net::XMPP2>
800
801	AnyEvent based XMPP (Jabber protocol) module family.
802
803	=item L<Net::FCP>
804
805	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
806	of AnyEvent.
807
808	=item L<Event::ExecFlow>
809
810	High level API for event-based execution flow control.
811
812	=item L<Coro>	1204	=item L<Coro>
813		1205
814	Has special support for AnyEvent via L<Coro::AnyEvent>.	1206	Has special support for AnyEvent via L<Coro::AnyEvent>, which allows you
		1207	to simply invert the flow control - don't call us, we will call you:
815		1208
816	=item L<IO::Lambda>	1209	async {
		1210	Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
		1211	print "5 seconds later!\n";
817		1212
818	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	1213	Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
		1214	my $line = <STDIN>; # works for ttys
		1215
		1216	AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
		1217	my ($body, $hdr) = Coro::rouse_wait;
		1218	};
819		1219
820	=back	1220	=back
821		1221
822	=cut	1222	=cut
823		1223
824	package AnyEvent;	1224	package AnyEvent;
825		1225
826	no warnings;	1226	# basically a tuned-down version of common::sense
827	use strict;	1227	sub common_sense {
		1228	# from common:.sense 3.4
		1229	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
		1230	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1231	$^H |= 0x00000600;
		1232	}
828		1233
		1234	BEGIN { AnyEvent::common_sense }
		1235
829	use Carp;	1236	use Carp ();
830		1237
831	our $VERSION = 4.22;	1238	our $VERSION = '6.14';
832	our $MODEL;	1239	our $MODEL;
833
834	our $AUTOLOAD;
835	our @ISA;	1240	our @ISA;
836
837	our @REGISTRY;	1241	our @REGISTRY;
838		1242	our $VERBOSE;
839	our $WIN32;	1243	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
		1244	our $MAX_SIGNAL_LATENCY = $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} || 10; # executes after the BEGIN block below (tainting!)
840		1245
841	BEGIN {	1246	BEGIN {
842	my $win32 = ! ! ($^O =~ /mswin32/i);	1247	require "AnyEvent/constants.pl";
843	eval "sub WIN32(){ $win32 }";
844	}
845		1248
846	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1249	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
847		1250
848	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1251	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1252	if ${^TAINT};
849		1253
850	{	1254	$ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
		1255	for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
		1256
		1257	@ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
		1258	if ${^TAINT};
		1259
		1260	# $ENV{PERL_ANYEVENT_xxx} now valid
		1261
		1262	$VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 4;
		1263
851	my $idx;	1264	my $idx;
852	$PROTOCOL{$_} = ++$idx	1265	$PROTOCOL{$_} = ++$idx
853	for reverse split /\s*,\s*/,	1266	for reverse split /\s*,\s*/,
854	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1267	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
855	}	1268	}
856		1269
		1270	our @post_detect;
		1271
		1272	sub post_detect(&) {
		1273	my ($cb) = @_;
		1274
		1275	push @post_detect, $cb;
		1276
		1277	defined wantarray
		1278	? bless \$cb, "AnyEvent::Util::postdetect"
		1279	: ()
		1280	}
		1281
		1282	sub AnyEvent::Util::postdetect::DESTROY {
		1283	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1284	}
		1285
		1286	our $POSTPONE_W;
		1287	our @POSTPONE;
		1288
		1289	sub _postpone_exec {
		1290	undef $POSTPONE_W;
		1291
		1292	&{ shift @POSTPONE }
		1293	while @POSTPONE;
		1294	}
		1295
		1296	sub postpone(&) {
		1297	push @POSTPONE, shift;
		1298
		1299	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1300
		1301	()
		1302	}
		1303
		1304	sub log($$;@) {
		1305	# only load the big bloated module when we actually are about to log something
		1306	if ($_[0] <= ($VERBOSE || 1)) { # also catches non-numeric levels(!) and fatal
		1307	local ($!, $@);
		1308	require AnyEvent::Log; # among other things, sets $VERBOSE to 9
		1309	# AnyEvent::Log overwrites this function
		1310	goto &log;
		1311	}
		1312
		1313	0 # not logged
		1314	}
		1315
		1316	sub _logger($;$) {
		1317	my ($level, $renabled) = @_;
		1318
		1319	$$renabled = $level <= $VERBOSE;
		1320
		1321	my $logger = [(caller)[0], $level, $renabled];
		1322
		1323	$AnyEvent::Log::LOGGER{$logger+0} = $logger;
		1324
		1325	# return unless defined wantarray;
		1326	#
		1327	# require AnyEvent::Util;
		1328	# my $guard = AnyEvent::Util::guard (sub {
		1329	# # "clean up"
		1330	# delete $LOGGER{$logger+0};
		1331	# });
		1332	#
		1333	# sub {
		1334	# return 0 unless $$renabled;
		1335	#
		1336	# $guard if 0; # keep guard alive, but don't cause runtime overhead
		1337	# require AnyEvent::Log unless $AnyEvent::Log::VERSION;
		1338	# package AnyEvent::Log;
		1339	# _log ($logger->[0], $level, @_) # logger->[0] has been converted at load time
		1340	# }
		1341	}
		1342
		1343	if (length $ENV{PERL_ANYEVENT_LOG}) {
		1344	require AnyEvent::Log; # AnyEvent::Log does the thing for us
		1345	}
		1346
857	my @models = (	1347	our @models = (
858	[EV:: => AnyEvent::Impl::EV::],	1348	[EV:: => AnyEvent::Impl::EV::],
859	[Event:: => AnyEvent::Impl::Event::],
860	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1349	[AnyEvent::Loop:: => AnyEvent::Impl::Perl::],
861	# everything below here will not be autoprobed	1350	# everything below here will not (normally) be autoprobed
862	# as the pureperl backend should work everywhere	1351	# as the pure perl backend should work everywhere
863	# and is usually faster	1352	# and is usually faster
		1353	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package, so msut be near the top
		1354	[Event:: => AnyEvent::Impl::Event::], # slow, stable
		1355	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
		1356	# everything below here should not be autoloaded
		1357	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
864	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1358	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
865	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
866	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
867	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1359	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
868	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1360	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
869	[Wx:: => AnyEvent::Impl::POE::],	1361	[Wx:: => AnyEvent::Impl::POE::],
870	[Prima:: => AnyEvent::Impl::POE::],	1362	[Prima:: => AnyEvent::Impl::POE::],
		1363	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
		1364	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
		1365	[FLTK:: => AnyEvent::Impl::FLTK::],
871	);	1366	);
872		1367
873	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1368	our @isa_hook;
874		1369
875	our @post_detect;	1370	sub _isa_set {
		1371	my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
876		1372
		1373	@{"$pkg[$_-1]::ISA"} = $pkg[$_]
		1374	for 1 .. $#pkg;
		1375
		1376	grep $_ && $_->[1], @isa_hook
		1377	and AE::_reset ();
		1378	}
		1379
		1380	# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
		1381	sub _isa_hook($$;$) {
		1382	my ($i, $pkg, $reset_ae) = @_;
		1383
		1384	$isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
		1385
		1386	_isa_set;
		1387	}
		1388
		1389	# all autoloaded methods reserve the complete glob, not just the method slot.
		1390	# due to bugs in perls method cache implementation.
		1391	our @methods = qw(io timer time now now_update signal child idle condvar);
		1392
877	sub post_detect(&) {	1393	sub detect() {
878	my ($cb) = @_;	1394	return $MODEL if $MODEL; # some programs keep references to detect
879		1395
880	if ($MODEL) {	1396	# IO::Async::Loop::AnyEvent is extremely evil, refuse to work with it
881	$cb->();	1397	# the author knows about the problems and what it does to AnyEvent as a whole
		1398	# (and the ability of others to use AnyEvent), but simply wants to abuse AnyEvent
		1399	# anyway.
		1400	AnyEvent::log fatal => "AnyEvent: IO::Async::Loop::AnyEvent detected - that module is broken by\n"
		1401	. "design, abuses internals and breaks AnyEvent - will not continue."
		1402	if exists $INC{"IO/Async/Loop/AnyEvent.pm"};
882		1403
883	1	1404	local $!; # for good measure
		1405	local $SIG{__DIE__}; # we use eval
		1406
		1407	# free some memory
		1408	*detect = sub () { $MODEL };
		1409	# undef &func doesn't correctly update the method cache. grmbl.
		1410	# so we delete the whole glob. grmbl.
		1411	# otoh, perl doesn't let me undef an active usb, but it lets me free
		1412	# a glob with an active sub. hrm. i hope it works, but perl is
		1413	# usually buggy in this department. sigh.
		1414	delete @{"AnyEvent::"}{@methods};
		1415	undef @methods;
		1416
		1417	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1418	my $model = $1;
		1419	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1420	if (eval "require $model") {
		1421	AnyEvent::log 7 => "loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.";
		1422	$MODEL = $model;
884	} else {	1423	} else {
885	push @post_detect, $cb;	1424	AnyEvent::log 4 => "unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
886		1425	}
887	defined wantarray
888	? bless \$cb, "AnyEvent::Util::PostDetect"
889	: ()
890	}	1426	}
891	}
892		1427
893	sub AnyEvent::Util::PostDetect::DESTROY {	1428	# check for already loaded models
894	@post_detect = grep $_ != ${$_[0]}, @post_detect;
895	}
896
897	sub detect() {
898	unless ($MODEL) {	1429	unless ($MODEL) {
899	no strict 'refs';	1430	for (@REGISTRY, @models) {
900	local $SIG{__DIE__};	1431	my ($package, $model) = @$_;
901		1432	if (${"$package\::VERSION"} > 0) {
902	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
903	my $model = "AnyEvent::Impl::$1";
904	if (eval "require $model") {	1433	if (eval "require $model") {
		1434	AnyEvent::log 7 => "autodetected model '$model', using it.";
905	$MODEL = $model;	1435	$MODEL = $model;
906	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1436	last;
907	} else {	1437	} else {
908	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1438	AnyEvent::log 8 => "detected event loop $package, but cannot load '$model', skipping: $@";
		1439	}
909	}	1440	}
910	}	1441	}
911		1442
912	# check for already loaded models
913	unless ($MODEL) {	1443	unless ($MODEL) {
		1444	# try to autoload a model
914	for (@REGISTRY, @models) {	1445	for (@REGISTRY, @models) {
915	my ($package, $model) = @$_;	1446	my ($package, $model) = @$_;
		1447	if (
		1448	eval "require $package"
916	if (${"$package\::VERSION"} > 0) {	1449	and ${"$package\::VERSION"} > 0
917	if (eval "require $model") {	1450	and eval "require $model"
		1451	) {
		1452	AnyEvent::log 7 => "autoloaded model '$model', using it.";
918	$MODEL = $model;	1453	$MODEL = $model;
919	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;
920	last;	1454	last;
921	}
922	}	1455	}
923	}	1456	}
924		1457
925	unless ($MODEL) {
926	# try to load a model
927
928	for (@REGISTRY, @models) {
929	my ($package, $model) = @$_;
930	if (eval "require $package"
931	and ${"$package\::VERSION"} > 0
932	and eval "require $model") {
933	$MODEL = $model;
934	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
935	last;
936	}
937	}
938
939	$MODEL	1458	$MODEL
940	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1459	or AnyEvent::log fatal => "AnyEvent: backend autodetection failed - did you properly install AnyEvent?";
941	}
942	}	1460	}
943
944	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
945
946	unshift @ISA, $MODEL;
947
948	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
949
950	(shift @post_detect)->() while @post_detect;
951	}	1461	}
952		1462
		1463	# free memory only needed for probing
		1464	undef @models;
		1465	undef @REGISTRY;
		1466
		1467	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1468
		1469	# now nuke some methods that are overridden by the backend.
		1470	# SUPER usage is not allowed in these.
		1471	for (qw(time signal child idle)) {
		1472	undef &{"AnyEvent::Base::$_"}
		1473	if defined &{"$MODEL\::$_"};
		1474	}
		1475
		1476	_isa_set;
		1477
		1478	# we're officially open!
		1479
		1480	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1481	require AnyEvent::Strict;
		1482	}
		1483
		1484	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1485	require AnyEvent::Debug;
		1486	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1487	}
		1488
		1489	if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1490	require AnyEvent::Socket;
		1491	require AnyEvent::Debug;
		1492
		1493	my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
		1494	$shell =~ s/\$\$/$$/g;
		1495
		1496	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1497	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1498	}
		1499
		1500	# now the anyevent environment is set up as the user told us to, so
		1501	# call the actual user code - post detects
		1502
		1503	(shift @post_detect)->() while @post_detect;
		1504	undef @post_detect;
		1505
		1506	*post_detect = sub(&) {
		1507	shift->();
		1508
		1509	undef
		1510	};
		1511
953	$MODEL	1512	$MODEL
954	}	1513	}
955		1514
956	sub AUTOLOAD {	1515	for my $name (@methods) {
957	(my $func = $AUTOLOAD) =~ s/.*://;	1516	*$name = sub {
958		1517	detect;
959	$method{$func}	1518	# we use goto because
960	or croak "$func: not a valid method for AnyEvent objects";	1519	# a) it makes the thunk more transparent
961		1520	# b) it allows us to delete the thunk later
962	detect unless $MODEL;	1521	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
963		1522	};
964	my $class = shift;
965	$class->$func (@_);
966	}	1523	}
967		1524
968	# utility function to dup a filehandle. this is used by many backends	1525	# utility function to dup a filehandle. this is used by many backends
969	# to support binding more than one watcher per filehandle (they usually	1526	# to support binding more than one watcher per filehandle (they usually
970	# allow only one watcher per fd, so we dup it to get a different one).	1527	# allow only one watcher per fd, so we dup it to get a different one).
971	sub _dupfh($$$$) {	1528	sub _dupfh($$;$$) {
972	my ($poll, $fh, $r, $w) = @_;	1529	my ($poll, $fh, $r, $w) = @_;
973		1530
974	require Fcntl;
975
976	# cygwin requires the fh mode to be matching, unix doesn't	1531	# cygwin requires the fh mode to be matching, unix doesn't
977	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1532	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
978	: $poll eq "w" ? ($w, ">")
979	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
980		1533
981	open my $fh2, "$mode&" . fileno $fh	1534	open my $fh2, $mode, $fh
982	or die "cannot dup() filehandle: $!";	1535	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
983		1536
984	# we assume CLOEXEC is already set by perl in all important cases	1537	# we assume CLOEXEC is already set by perl in all important cases
985		1538
986	($fh2, $rw)	1539	($fh2, $rw)
987	}	1540	}
988		1541
		1542	=head1 SIMPLIFIED AE API
		1543
		1544	Starting with version 5.0, AnyEvent officially supports a second, much
		1545	simpler, API that is designed to reduce the calling, typing and memory
		1546	overhead by using function call syntax and a fixed number of parameters.
		1547
		1548	See the L<AE> manpage for details.
		1549
		1550	=cut
		1551
		1552	package AE;
		1553
		1554	our $VERSION = $AnyEvent::VERSION;
		1555
		1556	sub _reset() {
		1557	eval q{
		1558	# fall back to the main API by default - backends and AnyEvent::Base
		1559	# implementations can overwrite these.
		1560
		1561	sub io($$$) {
		1562	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1563	}
		1564
		1565	sub timer($$$) {
		1566	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1567	}
		1568
		1569	sub signal($$) {
		1570	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1571	}
		1572
		1573	sub child($$) {
		1574	AnyEvent->child (pid => $_[0], cb => $_[1])
		1575	}
		1576
		1577	sub idle($) {
		1578	AnyEvent->idle (cb => $_[0]);
		1579	}
		1580
		1581	sub cv(;&) {
		1582	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1583	}
		1584
		1585	sub now() {
		1586	AnyEvent->now
		1587	}
		1588
		1589	sub now_update() {
		1590	AnyEvent->now_update
		1591	}
		1592
		1593	sub time() {
		1594	AnyEvent->time
		1595	}
		1596
		1597	*postpone = \&AnyEvent::postpone;
		1598	*log = \&AnyEvent::log;
		1599	};
		1600	die if $@;
		1601	}
		1602
		1603	BEGIN { _reset }
		1604
989	package AnyEvent::Base;	1605	package AnyEvent::Base;
990		1606
991	# default implementation for now and time	1607	# default implementations for many methods
992		1608
993	use Time::HiRes ();	1609	sub time {
		1610	eval q{ # poor man's autoloading {}
		1611	# probe for availability of Time::HiRes
		1612	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1613	*time = sub { Time::HiRes::time () };
		1614	*AE::time = \& Time::HiRes::time ;
		1615	*now = \&time;
		1616	AnyEvent::log 8 => "AnyEvent: using Time::HiRes for sub-second timing accuracy.";
		1617	# if (eval "use POSIX (); (POSIX::times())...
		1618	} else {
		1619	*time = sub { CORE::time };
		1620	*AE::time = sub (){ CORE::time };
		1621	*now = \&time;
		1622	AnyEvent::log 3 => "using built-in time(), WARNING, no sub-second resolution!";
		1623	}
		1624	};
		1625	die if $@;
994		1626
995	sub time { Time::HiRes::time }	1627	&time
996	sub now { Time::HiRes::time }	1628	}
		1629
		1630	*now = \&time;
		1631	sub now_update { }
		1632
		1633	sub _poll {
		1634	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1635	}
997		1636
998	# default implementation for ->condvar	1637	# default implementation for ->condvar
		1638	# in fact, the default should not be overwritten
999		1639
1000	sub condvar {	1640	sub condvar {
		1641	eval q{ # poor man's autoloading {}
		1642	*condvar = sub {
1001	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1643	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1644	};
		1645
		1646	*AE::cv = sub (;&) {
		1647	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1648	};
		1649	};
		1650	die if $@;
		1651
		1652	&condvar
1002	}	1653	}
1003		1654
1004	# default implementation for ->signal	1655	# default implementation for ->signal
1005		1656
1006	our %SIG_CB;	1657	our $HAVE_ASYNC_INTERRUPT;
		1658
		1659	sub _have_async_interrupt() {
		1660	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1661	&& eval "use Async::Interrupt 1.02 (); 1")
		1662	unless defined $HAVE_ASYNC_INTERRUPT;
		1663
		1664	$HAVE_ASYNC_INTERRUPT
		1665	}
		1666
		1667	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1668	our (%SIG_ASY, %SIG_ASY_W);
		1669	our ($SIG_COUNT, $SIG_TW);
		1670
		1671	# install a dummy wakeup watcher to reduce signal catching latency
		1672	# used by Impls
		1673	sub _sig_add() {
		1674	unless ($SIG_COUNT++) {
		1675	# try to align timer on a full-second boundary, if possible
		1676	my $NOW = AE::now;
		1677
		1678	$SIG_TW = AE::timer
		1679	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1680	$MAX_SIGNAL_LATENCY,
		1681	sub { } # just for the PERL_ASYNC_CHECK
		1682	;
		1683	}
		1684	}
		1685
		1686	sub _sig_del {
		1687	undef $SIG_TW
		1688	unless --$SIG_COUNT;
		1689	}
		1690
		1691	our $_sig_name_init; $_sig_name_init = sub {
		1692	eval q{ # poor man's autoloading {}
		1693	undef $_sig_name_init;
		1694
		1695	if (_have_async_interrupt) {
		1696	*sig2num = \&Async::Interrupt::sig2num;
		1697	*sig2name = \&Async::Interrupt::sig2name;
		1698	} else {
		1699	require Config;
		1700
		1701	my %signame2num;
		1702	@signame2num{ split ' ', $Config::Config{sig_name} }
		1703	= split ' ', $Config::Config{sig_num};
		1704
		1705	my @signum2name;
		1706	@signum2name[values %signame2num] = keys %signame2num;
		1707
		1708	*sig2num = sub($) {
		1709	$_[0] > 0 ? shift : $signame2num{+shift}
		1710	};
		1711	*sig2name = sub ($) {
		1712	$_[0] > 0 ? $signum2name[+shift] : shift
		1713	};
		1714	}
		1715	};
		1716	die if $@;
		1717	};
		1718
		1719	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1720	sub sig2name($) { &$_sig_name_init; &sig2name }
1007		1721
1008	sub signal {	1722	sub signal {
		1723	eval q{ # poor man's autoloading {}
		1724	# probe for availability of Async::Interrupt
		1725	if (_have_async_interrupt) {
		1726	AnyEvent::log 8 => "using Async::Interrupt for race-free signal handling.";
		1727
		1728	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1729	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
		1730
		1731	} else {
		1732	AnyEvent::log 8 => "using emulated perl signal handling with latency timer.";
		1733
		1734	if (AnyEvent::WIN32) {
		1735	require AnyEvent::Util;
		1736
		1737	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1738	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1739	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1740	} else {
		1741	pipe $SIGPIPE_R, $SIGPIPE_W;
		1742	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
		1743	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1744
		1745	# not strictly required, as $^F is normally 2, but let's make sure...
		1746	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1747	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1748	}
		1749
		1750	$SIGPIPE_R
		1751	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1752
		1753	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
		1754	}
		1755
		1756	*signal = $HAVE_ASYNC_INTERRUPT
		1757	? sub {
1009	my (undef, %arg) = @_;	1758	my (undef, %arg) = @_;
1010		1759
		1760	# async::interrupt
1011	my $signal = uc $arg{signal}	1761	my $signal = sig2num $arg{signal};
1012	or Carp::croak "required option 'signal' is missing";
1013
1014	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1762	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1763
		1764	$SIG_ASY{$signal} ||= new Async::Interrupt
		1765	cb => sub { undef $SIG_EV{$signal} },
		1766	signal => $signal,
		1767	pipe => [$SIGPIPE_R->filenos],
		1768	pipe_autodrain => 0,
		1769	;
		1770
		1771	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1772	}
		1773	: sub {
		1774	my (undef, %arg) = @_;
		1775
		1776	# pure perl
		1777	my $signal = sig2name $arg{signal};
		1778	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1779
1015	$SIG{$signal} ||= sub {	1780	$SIG{$signal} ||= sub {
		1781	local $!;
		1782	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1783	undef $SIG_EV{$signal};
		1784	};
		1785
		1786	# can't do signal processing without introducing races in pure perl,
		1787	# so limit the signal latency.
		1788	_sig_add;
		1789
		1790	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1791	}
		1792	;
		1793
		1794	*AnyEvent::Base::signal::DESTROY = sub {
		1795	my ($signal, $cb) = @{$_[0]};
		1796
		1797	_sig_del;
		1798
		1799	delete $SIG_CB{$signal}{$cb};
		1800
		1801	$HAVE_ASYNC_INTERRUPT
		1802	? delete $SIG_ASY{$signal}
		1803	: # delete doesn't work with older perls - they then
		1804	# print weird messages, or just unconditionally exit
		1805	# instead of getting the default action.
		1806	undef $SIG{$signal}
		1807	unless keys %{ $SIG_CB{$signal} };
		1808	};
		1809
		1810	*_signal_exec = sub {
		1811	$HAVE_ASYNC_INTERRUPT
		1812	? $SIGPIPE_R->drain
		1813	: sysread $SIGPIPE_R, (my $dummy), 9;
		1814
		1815	while (%SIG_EV) {
		1816	for (keys %SIG_EV) {
		1817	delete $SIG_EV{$_};
1016	$_->() for values %{ $SIG_CB{$signal} || {} };	1818	&$_ for values %{ $SIG_CB{$_} || {} };
		1819	}
		1820	}
		1821	};
1017	};	1822	};
		1823	die if $@;
1018		1824
1019	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1825	&signal
1020	}
1021
1022	sub AnyEvent::Base::Signal::DESTROY {
1023	my ($signal, $cb) = @{$_[0]};
1024
1025	delete $SIG_CB{$signal}{$cb};
1026
1027	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1028	}	1826	}
1029		1827
1030	# default implementation for ->child	1828	# default implementation for ->child
1031		1829
1032	our %PID_CB;	1830	our %PID_CB;
1033	our $CHLD_W;	1831	our $CHLD_W;
1034	our $CHLD_DELAY_W;	1832	our $CHLD_DELAY_W;
1035	our $PID_IDLE;
1036	our $WNOHANG;
1037		1833
1038	sub _child_wait {	1834	# used by many Impl's
1039	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1835	sub _emit_childstatus($$) {
		1836	my (undef, $rpid, $rstatus) = @_;
		1837
		1838	$_->($rpid, $rstatus)
1040	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1839	for values %{ $PID_CB{$rpid} || {} },
1041	(values %{ $PID_CB{0} || {} });	1840	values %{ $PID_CB{0} || {} };
1042	}
1043
1044	undef $PID_IDLE;
1045	}
1046
1047	sub _sigchld {
1048	# make sure we deliver these changes "synchronous" with the event loop.
1049	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
1050	undef $CHLD_DELAY_W;
1051	&_child_wait;
1052	});
1053	}	1841	}
1054		1842
1055	sub child {	1843	sub child {
		1844	eval q{ # poor man's autoloading {}
		1845	*_sigchld = sub {
		1846	my $pid;
		1847
		1848	AnyEvent->_emit_childstatus ($pid, $?)
		1849	while ($pid = waitpid -1, WNOHANG) > 0;
		1850	};
		1851
		1852	*child = sub {
1056	my (undef, %arg) = @_;	1853	my (undef, %arg) = @_;
1057		1854
1058	defined (my $pid = $arg{pid} + 0)	1855	my $pid = $arg{pid};
1059	or Carp::croak "required option 'pid' is missing";	1856	my $cb = $arg{cb};
1060		1857
1061	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1858	$PID_CB{$pid}{$cb+0} = $cb;
1062		1859
1063	unless ($WNOHANG) {
1064	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1065	}
1066
1067	unless ($CHLD_W) {	1860	unless ($CHLD_W) {
1068	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1861	$CHLD_W = AE::signal CHLD => \&_sigchld;
1069	# child could be a zombie already, so make at least one round	1862	# child could be a zombie already, so make at least one round
1070	&_sigchld;	1863	&_sigchld;
1071	}	1864	}
1072		1865
1073	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1866	bless [$pid, $cb+0], "AnyEvent::Base::child"
1074	}	1867	};
1075		1868
1076	sub AnyEvent::Base::Child::DESTROY {	1869	*AnyEvent::Base::child::DESTROY = sub {
1077	my ($pid, $cb) = @{$_[0]};	1870	my ($pid, $icb) = @{$_[0]};
1078		1871
1079	delete $PID_CB{$pid}{$cb};	1872	delete $PID_CB{$pid}{$icb};
1080	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1873	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1081		1874
1082	undef $CHLD_W unless keys %PID_CB;	1875	undef $CHLD_W unless keys %PID_CB;
		1876	};
		1877	};
		1878	die if $@;
		1879
		1880	&child
		1881	}
		1882
		1883	# idle emulation is done by simply using a timer, regardless
		1884	# of whether the process is idle or not, and not letting
		1885	# the callback use more than 50% of the time.
		1886	sub idle {
		1887	eval q{ # poor man's autoloading {}
		1888	*idle = sub {
		1889	my (undef, %arg) = @_;
		1890
		1891	my ($cb, $w, $rcb) = $arg{cb};
		1892
		1893	$rcb = sub {
		1894	if ($cb) {
		1895	$w = AE::time;
		1896	&$cb;
		1897	$w = AE::time - $w;
		1898
		1899	# never use more then 50% of the time for the idle watcher,
		1900	# within some limits
		1901	$w = 0.0001 if $w < 0.0001;
		1902	$w = 5 if $w > 5;
		1903
		1904	$w = AE::timer $w, 0, $rcb;
		1905	} else {
		1906	# clean up...
		1907	undef $w;
		1908	undef $rcb;
		1909	}
		1910	};
		1911
		1912	$w = AE::timer 0.05, 0, $rcb;
		1913
		1914	bless \\$cb, "AnyEvent::Base::idle"
		1915	};
		1916
		1917	*AnyEvent::Base::idle::DESTROY = sub {
		1918	undef $${$_[0]};
		1919	};
		1920	};
		1921	die if $@;
		1922
		1923	&idle
1083	}	1924	}
1084		1925
1085	package AnyEvent::CondVar;	1926	package AnyEvent::CondVar;
1086		1927
1087	our @ISA = AnyEvent::CondVar::Base::;	1928	our @ISA = AnyEvent::CondVar::Base::;
1088		1929
		1930	# only to be used for subclassing
		1931	sub new {
		1932	my $class = shift;
		1933	bless AnyEvent->condvar (@_), $class
		1934	}
		1935
1089	package AnyEvent::CondVar::Base;	1936	package AnyEvent::CondVar::Base;
1090		1937
1091	use overload	1938	#use overload
1092	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1939	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1093	fallback => 1;	1940	# fallback => 1;
		1941
		1942	# save 300+ kilobytes by dirtily hardcoding overloading
		1943	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1944	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1945	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1946	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1947
		1948	our $WAITING;
1094		1949
1095	sub _send {	1950	sub _send {
1096	# nop	1951	# nop
		1952	}
		1953
		1954	sub _wait {
		1955	AnyEvent->_poll until $_[0]{_ae_sent};
1097	}	1956	}
1098		1957
1099	sub send {	1958	sub send {
1100	my $cv = shift;	1959	my $cv = shift;
1101	$cv->{_ae_sent} = [@_];	1960	$cv->{_ae_sent} = [@_];
…		…
1110		1969
1111	sub ready {	1970	sub ready {
1112	$_[0]{_ae_sent}	1971	$_[0]{_ae_sent}
1113	}	1972	}
1114		1973
1115	sub _wait {
1116	AnyEvent->one_event while !$_[0]{_ae_sent};
1117	}
1118
1119	sub recv {	1974	sub recv {
		1975	unless ($_[0]{_ae_sent}) {
		1976	$WAITING
		1977	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1978
		1979	local $WAITING = 1;
1120	$_[0]->_wait;	1980	$_[0]->_wait;
		1981	}
1121		1982
1122	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1983	$_[0]{_ae_croak}
1123	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1984	and Carp::croak $_[0]{_ae_croak};
		1985
		1986	wantarray
		1987	? @{ $_[0]{_ae_sent} }
		1988	: $_[0]{_ae_sent}[0]
1124	}	1989	}
1125		1990
1126	sub cb {	1991	sub cb {
1127	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1992	my $cv = shift;
		1993
		1994	@_
		1995	and $cv->{_ae_cb} = shift
		1996	and $cv->{_ae_sent}
		1997	and (delete $cv->{_ae_cb})->($cv);
		1998
1128	$_[0]{_ae_cb}	1999	$cv->{_ae_cb}
1129	}	2000	}
1130		2001
1131	sub begin {	2002	sub begin {
1132	++$_[0]{_ae_counter};	2003	++$_[0]{_ae_counter};
1133	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	2004	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1138	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	2009	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1139	}	2010	}
1140		2011
1141	# undocumented/compatibility with pre-3.4	2012	# undocumented/compatibility with pre-3.4
1142	*broadcast = \&send;	2013	*broadcast = \&send;
1143	*wait = \&_wait;	2014	*wait = \&recv;
		2015
		2016	=head1 ERROR AND EXCEPTION HANDLING
		2017
		2018	In general, AnyEvent does not do any error handling - it relies on the
		2019	caller to do that if required. The L<AnyEvent::Strict> module (see also
		2020	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		2021	checking of all AnyEvent methods, however, which is highly useful during
		2022	development.
		2023
		2024	As for exception handling (i.e. runtime errors and exceptions thrown while
		2025	executing a callback), this is not only highly event-loop specific, but
		2026	also not in any way wrapped by this module, as this is the job of the main
		2027	program.
		2028
		2029	The pure perl event loop simply re-throws the exception (usually
		2030	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		2031	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		2032	so on.
		2033
		2034	=head1 ENVIRONMENT VARIABLES
		2035
		2036	AnyEvent supports a number of environment variables that tune the
		2037	runtime behaviour. They are usually evaluated when AnyEvent is
		2038	loaded, initialised, or a submodule that uses them is loaded. Many of
		2039	them also cause AnyEvent to load additional modules - for example,
		2040	C<PERL_ANYEVENT_DEBUG_WRAP> causes the L<AnyEvent::Debug> module to be
		2041	loaded.
		2042
		2043	All the environment variables documented here start with
		2044	C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
		2045	namespace. Other modules are encouraged (but by no means required) to use
		2046	C<PERL_ANYEVENT_SUBMODULE> if they have registered the AnyEvent::Submodule
		2047	namespace on CPAN, for any submodule. For example, L<AnyEvent::HTTP> could
		2048	be expected to use C<PERL_ANYEVENT_HTTP_PROXY> (it should not access env
		2049	variables starting with C<AE_>, see below).
		2050
		2051	All variables can also be set via the C<AE_> prefix, that is, instead
		2052	of setting C<PERL_ANYEVENT_VERBOSE> you can also set C<AE_VERBOSE>. In
		2053	case there is a clash btween anyevent and another program that uses
		2054	C<AE_something> you can set the corresponding C<PERL_ANYEVENT_something>
		2055	variable to the empty string, as those variables take precedence.
		2056
		2057	When AnyEvent is first loaded, it copies all C<AE_xxx> env variables
		2058	to their C<PERL_ANYEVENT_xxx> counterpart unless that variable already
		2059	exists. If taint mode is on, then AnyEvent will remove I<all> environment
		2060	variables starting with C<PERL_ANYEVENT_> from C<%ENV> (or replace them
		2061	with C<undef> or the empty string, if the corresaponding C<AE_> variable
		2062	is set).
		2063
		2064	The exact algorithm is currently:
		2065
		2066	1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
		2067	2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
		2068	3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
		2069
		2070	This ensures that child processes will not see the C<AE_> variables.
		2071
		2072	The following environment variables are currently known to AnyEvent:
		2073
		2074	=over 4
		2075
		2076	=item C<PERL_ANYEVENT_VERBOSE>
		2077
		2078	By default, AnyEvent will only log messages with loglevel C<3>
		2079	(C<critical>) or higher (see L<AnyEvent::Log>). You can set this
		2080	environment variable to a numerical loglevel to make AnyEvent more (or
		2081	less) talkative.
		2082
		2083	If you want to do more than just set the global logging level
		2084	you should have a look at C<PERL_ANYEVENT_LOG>, which allows much more
		2085	complex specifications.
		2086
		2087	When set to C<0> (C<off>), then no messages whatsoever will be logged with
		2088	the default logging settings.
		2089
		2090	When set to C<5> or higher (C<warn>), causes AnyEvent to warn about
		2091	unexpected conditions, such as not being able to load the event model
		2092	specified by C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an
		2093	exception - this is the minimum recommended level.
		2094
		2095	When set to C<7> or higher (info), cause AnyEvent to report which event model it
		2096	chooses.
		2097
		2098	When set to C<8> or higher (debug), then AnyEvent will report extra information on
		2099	which optional modules it loads and how it implements certain features.
		2100
		2101	=item C<PERL_ANYEVENT_LOG>
		2102
		2103	Accepts rather complex logging specifications. For example, you could log
		2104	all C<debug> messages of some module to stderr, warnings and above to
		2105	stderr, and errors and above to syslog, with:
		2106
		2107	PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
		2108
		2109	For the rather extensive details, see L<AnyEvent::Log>.
		2110
		2111	This variable is evaluated when AnyEvent (or L<AnyEvent::Log>) is loaded,
		2112	so will take effect even before AnyEvent has initialised itself.
		2113
		2114	Note that specifying this environment variable causes the L<AnyEvent::Log>
		2115	module to be loaded, while C<PERL_ANYEVENT_VERBOSE> does not, so only
		2116	using the latter saves a few hundred kB of memory until the first message
		2117	is being logged.
		2118
		2119	=item C<PERL_ANYEVENT_STRICT>
		2120
		2121	AnyEvent does not do much argument checking by default, as thorough
		2122	argument checking is very costly. Setting this variable to a true value
		2123	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		2124	check the arguments passed to most method calls. If it finds any problems,
		2125	it will croak.
		2126
		2127	In other words, enables "strict" mode.
		2128
		2129	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
		2130	>>, it is definitely recommended to keep it off in production. Keeping
		2131	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		2132	can be very useful, however.
		2133
		2134	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		2135
		2136	If this env variable is nonempty, then its contents will be interpreted by
		2137	C<AnyEvent::Socket::parse_hostport> and C<AnyEvent::Debug::shell> (after
		2138	replacing every occurance of C<$$> by the process pid). The shell object
		2139	is saved in C<$AnyEvent::Debug::SHELL>.
		2140
		2141	This happens when the first watcher is created.
		2142
		2143	For example, to bind a debug shell on a unix domain socket in
		2144	F<< /tmp/debug<pid>.sock >>, you could use this:
		2145
		2146	PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
		2147	# connect with e.g.: socat readline /tmp/debug123.sock
		2148
		2149	Or to bind to tcp port 4545 on localhost:
		2150
		2151	PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog
		2152	# connect with e.g.: telnet localhost 4545
		2153
		2154	Note that creating sockets in F</tmp> or on localhost is very unsafe on
		2155	multiuser systems.
		2156
		2157	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		2158
		2159	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		2160	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
		2161
		2162	=item C<PERL_ANYEVENT_MODEL>
		2163
		2164	This can be used to specify the event model to be used by AnyEvent, before
		2165	auto detection and -probing kicks in.
		2166
		2167	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		2168	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
		2169	resulting module name is loaded and - if the load was successful - used as
		2170	event model backend. If it fails to load then AnyEvent will proceed with
		2171	auto detection and -probing.
		2172
		2173	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		2174	nothing gets prepended and the module name is used as-is (hint: C<::> at
		2175	the end of a string designates a module name and quotes it appropriately).
		2176
		2177	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
		2178	could start your program like this:
		2179
		2180	PERL_ANYEVENT_MODEL=Perl perl ...
		2181
		2182	=item C<PERL_ANYEVENT_PROTOCOLS>
		2183
		2184	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		2185	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		2186	of auto probing).
		2187
		2188	Must be set to a comma-separated list of protocols or address families,
		2189	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		2190	used, and preference will be given to protocols mentioned earlier in the
		2191	list.
		2192
		2193	This variable can effectively be used for denial-of-service attacks
		2194	against local programs (e.g. when setuid), although the impact is likely
		2195	small, as the program has to handle conenction and other failures anyways.
		2196
		2197	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		2198	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		2199	- only support IPv4, never try to resolve or contact IPv6
		2200	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		2201	IPv6, but prefer IPv6 over IPv4.
		2202
		2203	=item C<PERL_ANYEVENT_HOSTS>
		2204
		2205	This variable, if specified, overrides the F</etc/hosts> file used by
		2206	L<AnyEvent::Socket>C<::resolve_sockaddr>, i.e. hosts aliases will be read
		2207	from that file instead.
		2208
		2209	=item C<PERL_ANYEVENT_EDNS0>
		2210
		2211	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension for
		2212	DNS. This extension is generally useful to reduce DNS traffic, especially
		2213	when DNSSEC is involved, but some (broken) firewalls drop such DNS
		2214	packets, which is why it is off by default.
		2215
		2216	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		2217	EDNS0 in its DNS requests.
		2218
		2219	=item C<PERL_ANYEVENT_MAX_FORKS>
		2220
		2221	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		2222	will create in parallel.
		2223
		2224	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		2225
		2226	The default value for the C<max_outstanding> parameter for the default DNS
		2227	resolver - this is the maximum number of parallel DNS requests that are
		2228	sent to the DNS server.
		2229
		2230	=item C<PERL_ANYEVENT_MAX_SIGNAL_LATENCY>
		2231
		2232	Perl has inherently racy signal handling (you can basically choose between
		2233	losing signals and memory corruption) - pure perl event loops (including
		2234	C<AnyEvent::Loop>, when C<Async::Interrupt> isn't available) therefore
		2235	have to poll regularly to avoid losing signals.
		2236
		2237	Some event loops are racy, but don't poll regularly, and some event loops
		2238	are written in C but are still racy. For those event loops, AnyEvent
		2239	installs a timer that regularly wakes up the event loop.
		2240
		2241	By default, the interval for this timer is C<10> seconds, but you can
		2242	override this delay with this environment variable (or by setting
		2243	the C<$AnyEvent::MAX_SIGNAL_LATENCY> variable before creating signal
		2244	watchers).
		2245
		2246	Lower values increase CPU (and energy) usage, higher values can introduce
		2247	long delays when reaping children or waiting for signals.
		2248
		2249	The L<AnyEvent::Async> module, if available, will be used to avoid this
		2250	polling (with most event loops).
		2251
		2252	=item C<PERL_ANYEVENT_RESOLV_CONF>
		2253
		2254	The absolute path to a F<resolv.conf>-style file to use instead of
		2255	F</etc/resolv.conf> (or the OS-specific configuration) in the default
		2256	resolver, or the empty string to select the default configuration.
		2257
		2258	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		2259
		2260	When neither C<ca_file> nor C<ca_path> was specified during
		2261	L<AnyEvent::TLS> context creation, and either of these environment
		2262	variables are nonempty, they will be used to specify CA certificate
		2263	locations instead of a system-dependent default.
		2264
		2265	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		2266
		2267	When these are set to C<1>, then the respective modules are not
		2268	loaded. Mostly good for testing AnyEvent itself.
		2269
		2270	=back
1144		2271
1145	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	2272	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1146		2273
1147	This is an advanced topic that you do not normally need to use AnyEvent in	2274	This is an advanced topic that you do not normally need to use AnyEvent in
1148	a module. This section is only of use to event loop authors who want to	2275	a module. This section is only of use to event loop authors who want to
…		…
1182		2309
1183	I<rxvt-unicode> also cheats a bit by not providing blocking access to	2310	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1184	condition variables: code blocking while waiting for a condition will	2311	condition variables: code blocking while waiting for a condition will
1185	C<die>. This still works with most modules/usages, and blocking calls must	2312	C<die>. This still works with most modules/usages, and blocking calls must
1186	not be done in an interactive application, so it makes sense.	2313	not be done in an interactive application, so it makes sense.
1187
1188	=head1 ENVIRONMENT VARIABLES
1189
1190	The following environment variables are used by this module:
1191
1192	=over 4
1193
1194	=item C<PERL_ANYEVENT_VERBOSE>
1195
1196	By default, AnyEvent will be completely silent except in fatal
1197	conditions. You can set this environment variable to make AnyEvent more
1198	talkative.
1199
1200	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1201	conditions, such as not being able to load the event model specified by
1202	C<PERL_ANYEVENT_MODEL>.
1203
1204	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1205	model it chooses.
1206
1207	=item C<PERL_ANYEVENT_STRICT>
1208
1209	AnyEvent does not do much argument checking by default, as thorough
1210	argument checking is very costly. Setting this variable to a true value
1211	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1212	check the arguments passed to most method calls. If it finds any problems
1213	it will croak.
1214
1215	In other words, enables "strict" mode.
1216
1217	Unlike C<use strict> it is definitely recommended ot keep it off in
1218	production.
1219
1220	=item C<PERL_ANYEVENT_MODEL>
1221
1222	This can be used to specify the event model to be used by AnyEvent, before
1223	auto detection and -probing kicks in. It must be a string consisting
1224	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1225	and the resulting module name is loaded and if the load was successful,
1226	used as event model. If it fails to load AnyEvent will proceed with
1227	auto detection and -probing.
1228
1229	This functionality might change in future versions.
1230
1231	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1232	could start your program like this:
1233
1234	PERL_ANYEVENT_MODEL=Perl perl ...
1235
1236	=item C<PERL_ANYEVENT_PROTOCOLS>
1237
1238	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1239	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1240	of auto probing).
1241
1242	Must be set to a comma-separated list of protocols or address families,
1243	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1244	used, and preference will be given to protocols mentioned earlier in the
1245	list.
1246
1247	This variable can effectively be used for denial-of-service attacks
1248	against local programs (e.g. when setuid), although the impact is likely
1249	small, as the program has to handle connection errors already-
1250
1251	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1252	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1253	- only support IPv4, never try to resolve or contact IPv6
1254	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1255	IPv6, but prefer IPv6 over IPv4.
1256
1257	=item C<PERL_ANYEVENT_EDNS0>
1258
1259	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1260	for DNS. This extension is generally useful to reduce DNS traffic, but
1261	some (broken) firewalls drop such DNS packets, which is why it is off by
1262	default.
1263
1264	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1265	EDNS0 in its DNS requests.
1266
1267	=item C<PERL_ANYEVENT_MAX_FORKS>
1268
1269	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1270	will create in parallel.
1271
1272	=back
1273		2314
1274	=head1 EXAMPLE PROGRAM	2315	=head1 EXAMPLE PROGRAM
1275		2316
1276	The following program uses an I/O watcher to read data from STDIN, a timer	2317	The following program uses an I/O watcher to read data from STDIN, a timer
1277	to display a message once per second, and a condition variable to quit the	2318	to display a message once per second, and a condition variable to quit the
…		…
1290	warn "read: $input\n"; # output what has been read	2331	warn "read: $input\n"; # output what has been read
1291	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2332	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1292	},	2333	},
1293	);	2334	);
1294		2335
1295	my $time_watcher; # can only be used once
1296
1297	sub new_timer {
1298	$timer = AnyEvent->timer (after => 1, cb => sub {	2336	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1299	warn "timeout\n"; # print 'timeout' about every second	2337	warn "timeout\n"; # print 'timeout' at most every second
1300	&new_timer; # and restart the time
1301	});	2338	});
1302	}
1303
1304	new_timer; # create first timer
1305		2339
1306	$cv->recv; # wait until user enters /^q/i	2340	$cv->recv; # wait until user enters /^q/i
1307		2341
1308	=head1 REAL-WORLD EXAMPLE	2342	=head1 REAL-WORLD EXAMPLE
1309		2343
…		…
1382		2416
1383	The actual code goes further and collects all errors (C<die>s, exceptions)	2417	The actual code goes further and collects all errors (C<die>s, exceptions)
1384	that occurred during request processing. The C<result> method detects	2418	that occurred during request processing. The C<result> method detects
1385	whether an exception as thrown (it is stored inside the $txn object)	2419	whether an exception as thrown (it is stored inside the $txn object)
1386	and just throws the exception, which means connection errors and other	2420	and just throws the exception, which means connection errors and other
1387	problems get reported tot he code that tries to use the result, not in a	2421	problems get reported to the code that tries to use the result, not in a
1388	random callback.	2422	random callback.
1389		2423
1390	All of this enables the following usage styles:	2424	All of this enables the following usage styles:
1391		2425
1392	1. Blocking:	2426	1. Blocking:
…		…
1440	through AnyEvent. The benchmark creates a lot of timers (with a zero	2474	through AnyEvent. The benchmark creates a lot of timers (with a zero
1441	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2475	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1442	which it is), lets them fire exactly once and destroys them again.	2476	which it is), lets them fire exactly once and destroys them again.
1443		2477
1444	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2478	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1445	distribution.	2479	distribution. It uses the L<AE> interface, which makes a real difference
		2480	for the EV and Perl backends only.
1446		2481
1447	=head3 Explanation of the columns	2482	=head3 Explanation of the columns
1448		2483
1449	I<watcher> is the number of event watchers created/destroyed. Since	2484	I<watcher> is the number of event watchers created/destroyed. Since
1450	different event models feature vastly different performances, each event	2485	different event models feature vastly different performances, each event
…		…
1471	watcher.	2506	watcher.
1472		2507
1473	=head3 Results	2508	=head3 Results
1474		2509
1475	name watchers bytes create invoke destroy comment	2510	name watchers bytes create invoke destroy comment
1476	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	2511	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1477	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	2512	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1478	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	2513	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1479	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	2514	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1480	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	2515	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1481	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	2516	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2517	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2518	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1482	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	2519	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1483	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	2520	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1484	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	2521	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1485	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	2522	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1486		2523
1487	=head3 Discussion	2524	=head3 Discussion
1488		2525
1489	The benchmark does I<not> measure scalability of the event loop very	2526	The benchmark does I<not> measure scalability of the event loop very
1490	well. For example, a select-based event loop (such as the pure perl one)	2527	well. For example, a select-based event loop (such as the pure perl one)
…		…
1502	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2539	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1503	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2540	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1504	cycles with POE.	2541	cycles with POE.
1505		2542
1506	C<EV> is the sole leader regarding speed and memory use, which are both	2543	C<EV> is the sole leader regarding speed and memory use, which are both
1507	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2544	maximal/minimal, respectively. When using the L<AE> API there is zero
		2545	overhead (when going through the AnyEvent API create is about 5-6 times
		2546	slower, with other times being equal, so still uses far less memory than
1508	far less memory than any other event loop and is still faster than Event	2547	any other event loop and is still faster than Event natively).
1509	natively.
1510		2548
1511	The pure perl implementation is hit in a few sweet spots (both the	2549	The pure perl implementation is hit in a few sweet spots (both the
1512	constant timeout and the use of a single fd hit optimisations in the perl	2550	constant timeout and the use of a single fd hit optimisations in the perl
1513	interpreter and the backend itself). Nevertheless this shows that it	2551	interpreter and the backend itself). Nevertheless this shows that it
1514	adds very little overhead in itself. Like any select-based backend its	2552	adds very little overhead in itself. Like any select-based backend its
1515	performance becomes really bad with lots of file descriptors (and few of	2553	performance becomes really bad with lots of file descriptors (and few of
1516	them active), of course, but this was not subject of this benchmark.	2554	them active), of course, but this was not subject of this benchmark.
1517		2555
1518	The C<Event> module has a relatively high setup and callback invocation	2556	The C<Event> module has a relatively high setup and callback invocation
1519	cost, but overall scores in on the third place.	2557	cost, but overall scores in on the third place.
		2558
		2559	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2560	when using its pure perl backend.
1520		2561
1521	C<Glib>'s memory usage is quite a bit higher, but it features a	2562	C<Glib>'s memory usage is quite a bit higher, but it features a
1522	faster callback invocation and overall ends up in the same class as	2563	faster callback invocation and overall ends up in the same class as
1523	C<Event>. However, Glib scales extremely badly, doubling the number of	2564	C<Event>. However, Glib scales extremely badly, doubling the number of
1524	watchers increases the processing time by more than a factor of four,	2565	watchers increases the processing time by more than a factor of four,
…		…
1559	(even when used without AnyEvent), but most event loops have acceptable	2600	(even when used without AnyEvent), but most event loops have acceptable
1560	performance with or without AnyEvent.	2601	performance with or without AnyEvent.
1561		2602
1562	=item * The overhead AnyEvent adds is usually much smaller than the overhead of	2603	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
1563	the actual event loop, only with extremely fast event loops such as EV	2604	the actual event loop, only with extremely fast event loops such as EV
1564	adds AnyEvent significant overhead.	2605	does AnyEvent add significant overhead.
1565		2606
1566	=item * You should avoid POE like the plague if you want performance or	2607	=item * You should avoid POE like the plague if you want performance or
1567	reasonable memory usage.	2608	reasonable memory usage.
1568		2609
1569	=back	2610	=back
…		…
1585	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2626	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1586	(1%) are active. This mirrors the activity of large servers with many	2627	(1%) are active. This mirrors the activity of large servers with many
1587	connections, most of which are idle at any one point in time.	2628	connections, most of which are idle at any one point in time.
1588		2629
1589	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2630	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1590	distribution.	2631	distribution. It uses the L<AE> interface, which makes a real difference
		2632	for the EV and Perl backends only.
1591		2633
1592	=head3 Explanation of the columns	2634	=head3 Explanation of the columns
1593		2635
1594	I<sockets> is the number of sockets, and twice the number of "servers" (as	2636	I<sockets> is the number of sockets, and twice the number of "servers" (as
1595	each server has a read and write socket end).	2637	each server has a read and write socket end).
…		…
1602	it to another server. This includes deleting the old timeout and creating	2644	it to another server. This includes deleting the old timeout and creating
1603	a new one that moves the timeout into the future.	2645	a new one that moves the timeout into the future.
1604		2646
1605	=head3 Results	2647	=head3 Results
1606		2648
1607	name sockets create request	2649	name sockets create request
1608	EV 20000 69.01 11.16	2650	EV 20000 62.66 7.99
1609	Perl 20000 73.32 35.87	2651	Perl 20000 68.32 32.64
1610	Event 20000 212.62 257.32	2652	IOAsync 20000 174.06 101.15 epoll
1611	Glib 20000 651.16 1896.30	2653	IOAsync 20000 174.67 610.84 poll
		2654	Event 20000 202.69 242.91
		2655	Glib 20000 557.01 1689.52
1612	POE 20000 349.67 12317.24 uses POE::Loop::Event	2656	POE 20000 341.54 12086.32 uses POE::Loop::Event
1613		2657
1614	=head3 Discussion	2658	=head3 Discussion
1615		2659
1616	This benchmark I<does> measure scalability and overall performance of the	2660	This benchmark I<does> measure scalability and overall performance of the
1617	particular event loop.	2661	particular event loop.
…		…
1619	EV is again fastest. Since it is using epoll on my system, the setup time	2663	EV is again fastest. Since it is using epoll on my system, the setup time
1620	is relatively high, though.	2664	is relatively high, though.
1621		2665
1622	Perl surprisingly comes second. It is much faster than the C-based event	2666	Perl surprisingly comes second. It is much faster than the C-based event
1623	loops Event and Glib.	2667	loops Event and Glib.
		2668
		2669	IO::Async performs very well when using its epoll backend, and still quite
		2670	good compared to Glib when using its pure perl backend.
1624		2671
1625	Event suffers from high setup time as well (look at its code and you will	2672	Event suffers from high setup time as well (look at its code and you will
1626	understand why). Callback invocation also has a high overhead compared to	2673	understand why). Callback invocation also has a high overhead compared to
1627	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2674	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1628	uses select or poll in basically all documented configurations.	2675	uses select or poll in basically all documented configurations.
…		…
1691	=item * C-based event loops perform very well with small number of	2738	=item * C-based event loops perform very well with small number of
1692	watchers, as the management overhead dominates.	2739	watchers, as the management overhead dominates.
1693		2740
1694	=back	2741	=back
1695		2742
		2743	=head2 THE IO::Lambda BENCHMARK
		2744
		2745	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2746	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2747	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2748	shouldn't come as a surprise to anybody). As such, the benchmark is
		2749	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2750	very optimal. But how would AnyEvent compare when used without the extra
		2751	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2752
		2753	The benchmark itself creates an echo-server, and then, for 500 times,
		2754	connects to the echo server, sends a line, waits for the reply, and then
		2755	creates the next connection. This is a rather bad benchmark, as it doesn't
		2756	test the efficiency of the framework or much non-blocking I/O, but it is a
		2757	benchmark nevertheless.
		2758
		2759	name runtime
		2760	Lambda/select 0.330 sec
		2761	+ optimized 0.122 sec
		2762	Lambda/AnyEvent 0.327 sec
		2763	+ optimized 0.138 sec
		2764	Raw sockets/select 0.077 sec
		2765	POE/select, components 0.662 sec
		2766	POE/select, raw sockets 0.226 sec
		2767	POE/select, optimized 0.404 sec
		2768
		2769	AnyEvent/select/nb 0.085 sec
		2770	AnyEvent/EV/nb 0.068 sec
		2771	+state machine 0.134 sec
		2772
		2773	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2774	benchmarks actually make blocking connects and use 100% blocking I/O,
		2775	defeating the purpose of an event-based solution. All of the newly
		2776	written AnyEvent benchmarks use 100% non-blocking connects (using
		2777	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2778	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2779	generally require a lot more bookkeeping and event handling than blocking
		2780	connects (which involve a single syscall only).
		2781
		2782	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2783	offers similar expressive power as POE and IO::Lambda, using conventional
		2784	Perl syntax. This means that both the echo server and the client are 100%
		2785	non-blocking, further placing it at a disadvantage.
		2786
		2787	As you can see, the AnyEvent + EV combination even beats the
		2788	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2789	backend easily beats IO::Lambda and POE.
		2790
		2791	And even the 100% non-blocking version written using the high-level (and
		2792	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2793	higher level ("unoptimised") abstractions by a large margin, even though
		2794	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
		2795
		2796	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2797	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2798	part of the IO::Lambda distribution and were used without any changes.
		2799
		2800
		2801	=head1 SIGNALS
		2802
		2803	AnyEvent currently installs handlers for these signals:
		2804
		2805	=over 4
		2806
		2807	=item SIGCHLD
		2808
		2809	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		2810	emulation for event loops that do not support them natively. Also, some
		2811	event loops install a similar handler.
		2812
		2813	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2814	AnyEvent will reset it to default, to avoid losing child exit statuses.
		2815
		2816	=item SIGPIPE
		2817
		2818	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		2819	when AnyEvent gets loaded.
		2820
		2821	The rationale for this is that AnyEvent users usually do not really depend
		2822	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		2823	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		2824	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		2825	some random socket.
		2826
		2827	The rationale for installing a no-op handler as opposed to ignoring it is
		2828	that this way, the handler will be restored to defaults on exec.
		2829
		2830	Feel free to install your own handler, or reset it to defaults.
		2831
		2832	=back
		2833
		2834	=cut
		2835
		2836	undef $SIG{CHLD}
		2837	if $SIG{CHLD} eq 'IGNORE';
		2838
		2839	$SIG{PIPE} = sub { }
		2840	unless defined $SIG{PIPE};
		2841
		2842	=head1 RECOMMENDED/OPTIONAL MODULES
		2843
		2844	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2845	its built-in modules) are required to use it.
		2846
		2847	That does not mean that AnyEvent won't take advantage of some additional
		2848	modules if they are installed.
		2849
		2850	This section explains which additional modules will be used, and how they
		2851	affect AnyEvent's operation.
		2852
		2853	=over 4
		2854
		2855	=item L<Async::Interrupt>
		2856
		2857	This slightly arcane module is used to implement fast signal handling: To
		2858	my knowledge, there is no way to do completely race-free and quick
		2859	signal handling in pure perl. To ensure that signals still get
		2860	delivered, AnyEvent will start an interval timer to wake up perl (and
		2861	catch the signals) with some delay (default is 10 seconds, look for
		2862	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2863
		2864	If this module is available, then it will be used to implement signal
		2865	catching, which means that signals will not be delayed, and the event loop
		2866	will not be interrupted regularly, which is more efficient (and good for
		2867	battery life on laptops).
		2868
		2869	This affects not just the pure-perl event loop, but also other event loops
		2870	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2871
		2872	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2873	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2874	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2875	does nothing for those backends.
		2876
		2877	=item L<EV>
		2878
		2879	This module isn't really "optional", as it is simply one of the backend
		2880	event loops that AnyEvent can use. However, it is simply the best event
		2881	loop available in terms of features, speed and stability: It supports
		2882	the AnyEvent API optimally, implements all the watcher types in XS, does
		2883	automatic timer adjustments even when no monotonic clock is available,
		2884	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2885	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2886	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2887
		2888	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2889	then this module will do nothing for you.
		2890
		2891	=item L<Guard>
		2892
		2893	The guard module, when used, will be used to implement
		2894	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2895	lot less memory), but otherwise doesn't affect guard operation much. It is
		2896	purely used for performance.
		2897
		2898	=item L<JSON> and L<JSON::XS>
		2899
		2900	One of these modules is required when you want to read or write JSON data
		2901	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2902	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2903
		2904	=item L<Net::SSLeay>
		2905
		2906	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2907	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2908	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2909
		2910	=item L<Time::HiRes>
		2911
		2912	This module is part of perl since release 5.008. It will be used when the
		2913	chosen event library does not come with a timing source of its own. The
		2914	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
		2915	try to use a monotonic clock for timing stability.
		2916
		2917	=back
		2918
1696		2919
1697	=head1 FORK	2920	=head1 FORK
1698		2921
1699	Most event libraries are not fork-safe. The ones who are usually are	2922	Most event libraries are not fork-safe. The ones who are usually are
1700	because they rely on inefficient but fork-safe C<select> or C<poll>	2923	because they rely on inefficient but fork-safe C<select> or C<poll> calls
1701	calls. Only L<EV> is fully fork-aware.	2924	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2925	are usually badly thought-out hacks that are incompatible with fork in
		2926	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2927	continue event-processing in both parent and child (or both, if you know
		2928	what you are doing).
		2929
		2930	This means that, in general, you cannot fork and do event processing in
		2931	the child if the event library was initialised before the fork (which
		2932	usually happens when the first AnyEvent watcher is created, or the library
		2933	is loaded).
1702		2934
1703	If you have to fork, you must either do so I<before> creating your first	2935	If you have to fork, you must either do so I<before> creating your first
1704	watcher OR you must not use AnyEvent at all in the child.	2936	watcher OR you must not use AnyEvent at all in the child OR you must do
		2937	something completely out of the scope of AnyEvent.
		2938
		2939	The problem of doing event processing in the parent I<and> the child
		2940	is much more complicated: even for backends that I<are> fork-aware or
		2941	fork-safe, their behaviour is not usually what you want: fork clones all
		2942	watchers, that means all timers, I/O watchers etc. are active in both
		2943	parent and child, which is almost never what you want. USing C<exec>
		2944	to start worker children from some kind of manage rprocess is usually
		2945	preferred, because it is much easier and cleaner, at the expense of having
		2946	to have another binary.
1705		2947
1706		2948
1707	=head1 SECURITY CONSIDERATIONS	2949	=head1 SECURITY CONSIDERATIONS
1708		2950
1709	AnyEvent can be forced to load any event model via	2951	AnyEvent can be forced to load any event model via
…		…
1721	use AnyEvent;	2963	use AnyEvent;
1722		2964
1723	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2965	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1724	be used to probe what backend is used and gain other information (which is	2966	be used to probe what backend is used and gain other information (which is
1725	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2967	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1726	$ENV{PERL_ANYEGENT_STRICT}.	2968	$ENV{PERL_ANYEVENT_STRICT}.
		2969
		2970	Note that AnyEvent will remove I<all> environment variables starting with
		2971	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2972	enabled.
1727		2973
1728		2974
1729	=head1 BUGS	2975	=head1 BUGS
1730		2976
1731	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2977	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1732	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2978	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1733	and check wether the leaks still show up. (Perl 5.10.0 has other annoying	2979	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1734	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as	2980	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1735	pronounced).	2981	pronounced).
1736		2982
1737		2983
1738	=head1 SEE ALSO	2984	=head1 SEE ALSO
1739		2985
1740	Utility functions: L<AnyEvent::Util>.	2986	Tutorial/Introduction: L<AnyEvent::Intro>.
1741		2987
1742	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2988	FAQ: L<AnyEvent::FAQ>.
1743	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2989
		2990	Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
		2991	(simply logging).
		2992
		2993	Development/Debugging: L<AnyEvent::Strict> (stricter checking),
		2994	L<AnyEvent::Debug> (interactive shell, watcher tracing).
		2995
		2996	Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
		2997	L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
		2998	L<Qt>, L<POE>, L<FLTK>.
1744		2999
1745	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	3000	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1746	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	3001	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1747	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	3002	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
		3003	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
1748	L<AnyEvent::Impl::POE>.	3004	L<AnyEvent::Impl::FLTK>.
1749		3005
1750	Non-blocking file handles, sockets, TCP clients and	3006	Non-blocking handles, pipes, stream sockets, TCP clients and
1751	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	3007	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1752		3008
1753	Asynchronous DNS: L<AnyEvent::DNS>.	3009	Asynchronous DNS: L<AnyEvent::DNS>.
1754		3010
1755	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	3011	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
1756		3012
1757	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	3013	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
		3014	L<AnyEvent::HTTP>.
1758		3015
1759		3016
1760	=head1 AUTHOR	3017	=head1 AUTHOR
1761		3018
1762	Marc Lehmann <schmorp@schmorp.de>	3019	Marc Lehmann <schmorp@schmorp.de>

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