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Revision 1.389 by root, Tue Oct 4 05:34:50 2011 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
11	# file descriptor readable	15	# file handle or descriptor readable
12	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
13		17
14	# one-shot or repeating timers	18	# one-shot or repeating timers
15	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
16	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
17		21
18	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
19	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
20		24
21	# POSIX signal	25	# POSIX signal
…		…
39	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
40		44
41	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
42	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
43	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.
44		58
45	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	59	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
46		60
47	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
48	nowadays. So what is different about AnyEvent?	62	nowadays. So what is different about AnyEvent?
…		…
64	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
65	model you use.	79	model you use.
66		80
67	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
68	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
69	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
70	cannot use anything else, as they are simply incompatible to everything	84	cannot use anything else, as they are simply incompatible to everything
71	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
72	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.
73		87
74	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	88	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
75	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
76	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
77	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
78	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
79	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
80	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,
81	to AnyEvent, too, so it is future-proof).	95	so it is future-proof).
82		96
83	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
84	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
85	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
86	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
87	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
88	technically possible.	102	technically possible.
89		103
90	Of course, AnyEvent comes with a big (and fully optional!) toolbox	104	Of course, AnyEvent comes with a big (and fully optional!) toolbox
91	of useful functionality, such as an asynchronous DNS resolver, 100%	105	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
97	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
98	model, you should I<not> use this module.	112	model, you should I<not> use this module.
99		113
100	=head1 DESCRIPTION	114	=head1 DESCRIPTION
101		115
102	L<AnyEvent> provides an identical interface to multiple event loops. This	116	L<AnyEvent> provides a uniform interface to various event loops. This
103	allows module authors to utilise an event loop without forcing module	117	allows module authors to use event loop functionality without forcing
104	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
105	peacefully at any one time).	119	than one event loop cannot coexist peacefully).
106		120
107	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>
108	module.	122	module.
109		123
110	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
111	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
112	following modules is already loaded: L<EV>,	126	following modules is already loaded: L<EV>, L<AnyEvent::Loop>,
113	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
114	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
115	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
116	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
117	be successfully loaded will be used. If, after this, still none could be	131	the other two are not normally tried.
118	found, AnyEvent will fall back to a pure-perl event loop, which is not
119	very efficient, but should work everywhere.
120		132
121	Because AnyEvent first checks for modules that are already loaded, loading	133	Because AnyEvent first checks for modules that are already loaded, loading
122	an event model explicitly before first using AnyEvent will likely make	134	an event model explicitly before first using AnyEvent will likely make
123	that model the default. For example:	135	that model the default. For example:
124		136
…		…
126	use AnyEvent;	138	use AnyEvent;
127		139
128	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
129		141
130	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
131	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,
132	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
133		146
134	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called C<AnyEvent::Loop>. Like
135	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
136	explicitly and enjoy the high availability of that event loop :)	149	availability of that event loop :)
137		150
138	=head1 WATCHERS	151	=head1 WATCHERS
139		152
140	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
141	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
…		…
146	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
147	is in control).	160	is in control).
148		161
149	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
150	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<	163	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
151	callbacks must not C<die> >>. The former is good programming practise in	164	callbacks must not C<die> >>. The former is good programming practice in
152	Perl and the latter stems from the fact that exception handling differs	165	Perl and the latter stems from the fact that exception handling differs
153	widely between event loops.	166	widely between event loops.
154		167
155	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
156	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
157	to it).	170	to it).
158		171
159	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.
160		173
161	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
162	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.
163		176
164	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
165		178
166	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
167	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
168	undef $w;	181	undef $w;
169	});	182	});
…		…
172	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
173	declared.	186	declared.
174		187
175	=head2 I/O WATCHERS	188	=head2 I/O WATCHERS
176		189
		190	$w = AnyEvent->io (
		191	fh => <filehandle_or_fileno>,
		192	poll => <"r" or "w">,
		193	cb => <callback>,
		194	);
		195
177	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
178	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
179		198
180	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch	199	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
181	for events (AnyEvent might or might not keep a reference to this file	200	for events (AnyEvent might or might not keep a reference to this file
182	handle). Note that only file handles pointing to things for which	201	handle). Note that only file handles pointing to things for which
183	non-blocking operation makes sense are allowed. This includes sockets,	202	non-blocking operation makes sense are allowed. This includes sockets,
184	most character devices, pipes, fifos and so on, but not for example files	203	most character devices, pipes, fifos and so on, but not for example files
185	or block devices.	204	or block devices.
…		…
195		214
196	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.
197	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
198	underlying file descriptor.	217	underlying file descriptor.
199		218
200	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
201	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
202	handles.	221	handles.
203		222
204	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
205	watcher.	224	watcher.
…		…
210	undef $w;	229	undef $w;
211	});	230	});
212		231
213	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
214		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
215	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 >>
216	method with the following mandatory arguments:	243	method with the following mandatory arguments:
217		244
218	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
219	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
…		…
221		248
222	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
223	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
224	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
225		252
226	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
227	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
228	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
229	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
230	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.
231		258
232	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
233	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
234	only approximate.	261	only approximate.
235		262
236	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
237		264
238	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
256		283
257	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
258	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
259	"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
260	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
261	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.
262		289
263	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
264	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
265	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)
266	timers.	293	timers.
267		294
268	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
269	AnyEvent API.	296	AnyEvent API.
…		…
291	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
292	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
293		320
294	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
295	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
296	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
297		324
298	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
299	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
300		327
301	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>
302	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
303		330
304	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
305	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
306	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
307	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
308	after three seconds.	335	after three seconds.
309		336
…		…
329	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	356	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
330	account.	357	account.
331		358
332	=item AnyEvent->now_update	359	=item AnyEvent->now_update
333		360
334	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache	361	Some event loops (such as L<EV> or L<AnyEvent::Loop>) cache the current
335	the current time for each loop iteration (see the discussion of L<<	362	time for each loop iteration (see the discussion of L<< AnyEvent->now >>,
336	AnyEvent->now >>, above).	363	above).
337		364
338	When a callback runs for a long time (or when the process sleeps), then	365	When a callback runs for a long time (or when the process sleeps), then
339	this "current" time will differ substantially from the real time, which	366	this "current" time will differ substantially from the real time, which
340	might affect timers and time-outs.	367	might affect timers and time-outs.
341		368
342	When this is the case, you can call this method, which will update the	369	When this is the case, you can call this method, which will update the
343	event loop's idea of "current time".	370	event loop's idea of "current time".
344		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
345	Note that updating the time I<might> cause some events to be handled.	379	Note that updating the time I<might> cause some events to be handled.
346		380
347	=back	381	=back
348		382
349	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
350		386
351	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
352	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
353	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
354		390
…		…
360	invocation, and callback invocation will be synchronous. Synchronous means	396	invocation, and callback invocation will be synchronous. Synchronous means
361	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,
362	but it is guaranteed not to interrupt any other callbacks.	398	but it is guaranteed not to interrupt any other callbacks.
363		399
364	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
365	between multiple watchers.	401	between multiple watchers, and AnyEvent will ensure that signals will not
		402	interrupt your program at bad times.
366		403
367	This watcher might use C<%SIG>, so programs overwriting those signals	404	This watcher might use C<%SIG> (depending on the event loop used),
368	directly will likely not work correctly.	405	so programs overwriting those signals directly will likely not work
		406	correctly.
369		407
370	Example: exit on SIGINT	408	Example: exit on SIGINT
371		409
372	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
373		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling)
		421	or "unsafe" (asynchronous) - the former might delay signal delivery
		422	indefinitely, the latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
		429	=head3 Signal Races, Delays and Workarounds
		430
		431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support
		432	attaching callbacks to signals in a generic way, which is a pity,
		433	as you cannot do race-free signal handling in perl, requiring
		434	C libraries for this. AnyEvent will try to do its best, which
		435	means in some cases, signals will be delayed. The maximum time
		436	a signal might be delayed is 10 seconds by default, but can
		437	be overriden via C<$ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY}> or
		438	C<$AnyEvent::MAX_SIGNAL_LATENCY> - see the Ö<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
374	=head2 CHILD PROCESS WATCHERS	447	=head2 CHILD PROCESS WATCHERS
375		448
		449	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		450
376	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.
377		452
378	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,
379	watches for any child process exit). The watcher will triggered only when	454	using C<0> watches for any child process exit, on others this will
380	the child process has finished and an exit status is available, not on	455	croak). The watcher will be triggered only when the child process has
381	any trace events (stopped/continued).	456	finished and an exit status is available, not on any trace events
		457	(stopped/continued).
382		458
383	The callback will be called with the pid and exit status (as returned by	459	The callback will be called with the pid and exit status (as returned by
384	waitpid), so unlike other watcher types, you I<can> rely on child watcher	460	waitpid), so unlike other watcher types, you I<can> rely on child watcher
385	callback arguments.	461	callback arguments.
386		462
…		…
391		467
392	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
393	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
394	have exited already (and no SIGCHLD will be sent anymore).	470	have exited already (and no SIGCHLD will be sent anymore).
395		471
396	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
397	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
398	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.
399		478
400	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
401	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
402	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.
403		487
404	Example: fork a process and wait for it	488	Example: fork a process and wait for it
405		489
406	my $done = AnyEvent->condvar;	490	my $done = AnyEvent->condvar;
407		491
…		…
419	# do something else, then wait for process exit	503	# do something else, then wait for process exit
420	$done->recv;	504	$done->recv;
421		505
422	=head2 IDLE WATCHERS	506	=head2 IDLE WATCHERS
423		507
424	Sometimes there is a need to do something, but it is not so important	508	$w = AnyEvent->idle (cb => <callback>);
425	to do it instantly, but only when there is nothing better to do. This
426	"nothing better to do" is usually defined to be "no other events need
427	attention by the event loop".
428		509
429	Idle watchers ideally get invoked when the event loop has nothing	510	This will repeatedly invoke the callback after the process becomes idle,
430	better to do, just before it would block the process to wait for new	511	until either the watcher is destroyed or new events have been detected.
431	events. Instead of blocking, the idle watcher is invoked.
432		512
433	Most event loops unfortunately do not really support idle watchers (only	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
434	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	523	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
435	will simply call the callback "from time to time".	524	will simply call the callback "from time to time".
436		525
437	Example: read lines from STDIN, but only process them when the	526	Example: read lines from STDIN, but only process them when the
438	program is otherwise idle:	527	program is otherwise idle:
…		…
454	});	543	});
455	});	544	});
456		545
457	=head2 CONDITION VARIABLES	546	=head2 CONDITION VARIABLES
458		547
		548	$cv = AnyEvent->condvar;
		549
		550	$cv->send (<list>);
		551	my @res = $cv->recv;
		552
459	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
460	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
461	will actively watch for new events and call your callbacks.	555	will actively watch for new events and call your callbacks.
462		556
463	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
464	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).
465		559
466	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
467	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.
468		564
469	Condition variables can be created by calling the C<< AnyEvent->condvar	565	Condition variables can be created by calling the C<< AnyEvent->condvar
470	>> method, usually without arguments. The only argument pair allowed is	566	>> method, usually without arguments. The only argument pair allowed is
471
472	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
473	becomes true, with the condition variable as the first argument (but not	568	becomes true, with the condition variable as the first argument (but not
474	the results).	569	the results).
475		570
476	After creation, the condition variable is "false" until it becomes "true"	571	After creation, the condition variable is "false" until it becomes "true"
477	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
478	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<<
479	->send >> method).	574	->send >> method).
480		575
481	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
482	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:
483	in time where multiple outstanding events have been processed. And yet	578
484	another way to call them is transactions - each condition variable can be	579	=over 4
485	used to represent a transaction, which finishes at some point and delivers	580
486	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
487		599
488	Condition variables are very useful to signal that something has finished,	600	Condition variables are very useful to signal that something has finished,
489	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,
490	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
491	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
…		…
504		616
505	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
506	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
507	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
508	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
509	it's C<new> method in your own C<new> method.	621	its C<new> method in your own C<new> method.
510		622
511	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
512	eventually calls C<< -> send >>, and the "consumer side", which waits	624	eventually calls C<< -> send >>, and the "consumer side", which waits
513	for the send to occur.	625	for the send to occur.
514		626
515	Example: wait for a timer.	627	Example: wait for a timer.
516		628
517	# wait till the result is ready	629	# condition: "wait till the timer is fired"
518	my $result_ready = AnyEvent->condvar;	630	my $timer_fired = AnyEvent->condvar;
519		631
520	# do something such as adding a timer	632	# create the timer - we could wait for, say
521	# or socket watcher the calls $result_ready->send	633	# a handle becomign ready, or even an
522	# when the "result" is ready.	634	# AnyEvent::HTTP request to finish, but
523	# in this case, we simply use a timer:	635	# in this case, we simply use a timer:
524	my $w = AnyEvent->timer (	636	my $w = AnyEvent->timer (
525	after => 1,	637	after => 1,
526	cb => sub { $result_ready->send },	638	cb => sub { $timer_fired->send },
527	);	639	);
528		640
529	# this "blocks" (while handling events) till the callback	641	# this "blocks" (while handling events) till the callback
530	# calls send	642	# calls ->send
531	$result_ready->recv;	643	$timer_fired->recv;
532		644
533	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
534	condition variables are also code references.	646	variables are also callable directly.
535		647
536	my $done = AnyEvent->condvar;	648	my $done = AnyEvent->condvar;
537	my $delay = AnyEvent->timer (after => 5, cb => $done);	649	my $delay = AnyEvent->timer (after => 5, cb => $done);
538	$done->recv;	650	$done->recv;
539		651
…		…
545		657
546	...	658	...
547		659
548	my @info = $couchdb->info->recv;	660	my @info = $couchdb->info->recv;
549		661
550	And this is how you would just ste a callback to be called whenever the	662	And this is how you would just set a callback to be called whenever the
551	results are available:	663	results are available:
552		664
553	$couchdb->info->cb (sub {	665	$couchdb->info->cb (sub {
554	my @info = $_[0]->recv;	666	my @info = $_[0]->recv;
555	});	667	});
…		…
573	immediately from within send.	685	immediately from within send.
574		686
575	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
576	future C<< ->recv >> calls.	688	future C<< ->recv >> calls.
577		689
578	Condition variables are overloaded so one can call them directly	690	Condition variables are overloaded so one can call them directly (as if
579	(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
580	C<send>. Note, however, that many C-based event loops do not handle	692	C<send>.
581	overloading, so as tempting as it may be, passing a condition variable
582	instead of a callback does not work. Both the pure perl and EV loops
583	support overloading, however, as well as all functions that use perl to
584	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
585	example).
586		693
587	=item $cv->croak ($error)	694	=item $cv->croak ($error)
588		695
589	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
590	C<Carp::croak> with the given error message/object/scalar.	697	C<Carp::croak> with the given error message/object/scalar.
591		698
592	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
593	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.
594		705
595	=item $cv->begin ([group callback])	706	=item $cv->begin ([group callback])
596		707
597	=item $cv->end	708	=item $cv->end
598
599	These two methods are EXPERIMENTAL and MIGHT CHANGE.
600		709
601	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
602	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
603	to use a condition variable for the whole process.	712	to use a condition variable for the whole process.
604		713
605	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
606	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
607	>>, 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
608	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
609	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.
610		720
611	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:
612		728
613	my $cv = AnyEvent->condvar;	729	my $cv = AnyEvent->condvar;
614		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
615	my %result;	755	my %result;
616	$cv->begin (sub { $cv->send (\%result) });	756	$cv->begin (sub { shift->send (\%result) });
617		757
618	for my $host (@list_of_hosts) {	758	for my $host (@list_of_hosts) {
619	$cv->begin;	759	$cv->begin;
620	ping_host_then_call_callback $host, sub {	760	ping_host_then_call_callback $host, sub {
621	$result{$host} = ...;	761	$result{$host} = ...;
…		…
636	loop, which serves two important purposes: first, it sets the callback	776	loop, which serves two important purposes: first, it sets the callback
637	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
638	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
639	doesn't execute once).	779	doesn't execute once).
640		780
641	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
642	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
643	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
644	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>.
645		786
646	=back	787	=back
647		788
648	=head3 METHODS FOR CONSUMERS	789	=head3 METHODS FOR CONSUMERS
649		790
…		…
653	=over 4	794	=over 4
654		795
655	=item $cv->recv	796	=item $cv->recv
656		797
657	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	798	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
658	>> methods have been called on c<$cv>, while servicing other watchers	799	>> methods have been called on C<$cv>, while servicing other watchers
659	normally.	800	normally.
660		801
661	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
662	will return immediately.	803	will return immediately.
663		804
…		…
665	function will call C<croak>.	806	function will call C<croak>.
666		807
667	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,
668	in scalar context only the first one will be returned.	809	in scalar context only the first one will be returned.
669		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
670	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
671	(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
672	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
673	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
674	condition variables with some kind of request results and supporting	822	condition variables with some kind of request results and supporting
675	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,
676	while still supporting blocking waits if the caller so desires).	824	while still supporting blocking waits if the caller so desires).
677		825
678	Another reason I<never> to C<< ->recv >> in a module is that you cannot
679	sensibly have two C<< ->recv >>'s in parallel, as that would require
680	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
681	can supply.
682
683	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
684	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
685	versions and also integrates coroutines into AnyEvent, making blocking
686	C<< ->recv >> calls perfectly safe as long as they are done from another
687	coroutine (one that doesn't run the event loop).
688
689	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
690	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
691	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
692	waits otherwise.	829	waits otherwise.
693		830
694	=item $bool = $cv->ready	831	=item $bool = $cv->ready
…		…
700		837
701	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
702	replaces it before doing so.	839	replaces it before doing so.
703		840
704	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
705	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
706	variable itself. Calling C<recv> inside the callback or at any later time	843	condition variable itself. If the condition is already true, the
707	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.
708		846
709	=back	847	=back
710		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
711	=head1 GLOBAL VARIABLES AND FUNCTIONS	912	=head1 GLOBAL VARIABLES AND FUNCTIONS
712		913
		914	These are not normally required to use AnyEvent, but can be useful to
		915	write AnyEvent extension modules.
		916
713	=over 4	917	=over 4
714		918
715	=item $AnyEvent::MODEL	919	=item $AnyEvent::MODEL
716		920
717	Contains C<undef> until the first watcher is being created. Then it	921	Contains C<undef> until the first watcher is being created, before the
		922	backend has been autodetected.
		923
718	contains the event model that is being used, which is the name of the	924	Afterwards it contains the event model that is being used, which is the
719	Perl class implementing the model. This class is usually one of the	925	name of the Perl class implementing the model. This class is usually one
720	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	926	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
721	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	927	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
722		928	will be C<urxvt::anyevent>).
723	The known classes so far are:
724
725	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
726	AnyEvent::Impl::Event based on Event, second best choice.
727	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
728	AnyEvent::Impl::Glib based on Glib, third-best choice.
729	AnyEvent::Impl::Tk based on Tk, very bad choice.
730	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
731	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
732	AnyEvent::Impl::POE based on POE, not generic enough for full support.
733
734	There is no support for WxWidgets, as WxWidgets has no support for
735	watching file handles. However, you can use WxWidgets through the
736	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
737	second, which was considered to be too horrible to even consider for
738	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
739	it's adaptor.
740
741	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
742	autodetecting them.
743		929
744	=item AnyEvent::detect	930	=item AnyEvent::detect
745		931
746	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	932	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
747	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
748	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
749	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>.
750		943
751	=item $guard = AnyEvent::post_detect { BLOCK }	944	=item $guard = AnyEvent::post_detect { BLOCK }
752		945
753	Arranges for the code block to be executed as soon as the event model is	946	Arranges for the code block to be executed as soon as the event model is
754	autodetected (or immediately if this has already happened).	947	autodetected (or immediately if that has already happened).
		948
		949	The block will be executed I<after> the actual backend has been detected
		950	(C<$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.
755		959
756	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
757	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
758	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 ||= $guard;
759		980
760	=item @AnyEvent::post_detect	981	=item @AnyEvent::post_detect
761		982
762	If there are any code references in this array (you can C<push> to it	983	If there are any code references in this array (you can C<push> to it
763	before or after loading AnyEvent), then they will called directly after	984	before or after loading AnyEvent), then they will be called directly
764	the event loop has been chosen.	985	after the event loop has been chosen.
765		986
766	You should check C<$AnyEvent::MODEL> before adding to this array, though:	987	You should check C<$AnyEvent::MODEL> before adding to this array, though:
767	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
768	and the array will be ignored.	989	array will be ignored.
769		990
770	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.
771		1069
772	=back	1070	=back
773		1071
774	=head1 WHAT TO DO IN A MODULE	1072	=head1 WHAT TO DO IN A MODULE
775		1073
…		…
786	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
787	events is to stay interactive.	1085	events is to stay interactive.
788		1086
789	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
790	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
791	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 >>
792	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).
793		1091
794	=head1 WHAT TO DO IN THE MAIN PROGRAM	1092	=head1 WHAT TO DO IN THE MAIN PROGRAM
795		1093
796	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
797	dictate which event model to use.	1095	dictate which event model to use.
798		1096
799	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
800	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
801	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.
802		1102
803	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
804	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
805	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
806	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
807	modules might create watchers when they are loaded, and AnyEvent will	1107	modules might create watchers when they are loaded, and AnyEvent will
808	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
809	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.
810		1110
811	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
812	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1112	C<AnyEvent::Loop> module, which gives you similar behaviour
813	everywhere, but letting AnyEvent chose the model is generally better.	1113	everywhere, but letting AnyEvent chose the model is generally better.
814		1114
815	=head2 MAINLOOP EMULATION	1115	=head2 MAINLOOP EMULATION
816		1116
817	Sometimes (often for short test scripts, or even standalone programs who	1117	Sometimes (often for short test scripts, or even standalone programs who
…		…
830		1130
831		1131
832	=head1 OTHER MODULES	1132	=head1 OTHER MODULES
833		1133
834	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
835	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1135	AnyEvent as a client and can therefore be mixed easily with other
836	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
837	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 :)
838		1141
839	=over 4	1142	=over 4
840		1143
841	=item L<AnyEvent::Util>	1144	=item L<AnyEvent::Util>
842		1145
843	Contains various utility functions that replace often-used but blocking	1146	Contains various utility functions that replace often-used blocking
844	functions such as C<inet_aton> by event-/callback-based versions.	1147	functions such as C<inet_aton> with event/callback-based versions.
845		1148
846	=item L<AnyEvent::Socket>	1149	=item L<AnyEvent::Socket>
847		1150
848	Provides various utility functions for (internet protocol) sockets,	1151	Provides various utility functions for (internet protocol) sockets,
849	addresses and name resolution. Also functions to create non-blocking tcp	1152	addresses and name resolution. Also functions to create non-blocking tcp
…		…
851		1154
852	=item L<AnyEvent::Handle>	1155	=item L<AnyEvent::Handle>
853		1156
854	Provide read and write buffers, manages watchers for reads and writes,	1157	Provide read and write buffers, manages watchers for reads and writes,
855	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
856	non-blocking SSL/TLS.	1159	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
857		1160
858	=item L<AnyEvent::DNS>	1161	=item L<AnyEvent::DNS>
859		1162
860	Provides rich asynchronous DNS resolver capabilities.	1163	Provides rich asynchronous DNS resolver capabilities.
861		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
862	=item L<AnyEvent::HTTP>	1171	=item L<AnyEvent::AIO>
863		1172
864	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
865	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.
866		1195
867	=item L<AnyEvent::HTTPD>	1196	=item L<AnyEvent::HTTPD>
868		1197
869	Provides a simple web application server framework.	1198	A simple embedded webserver.
870		1199
871	=item L<AnyEvent::FastPing>	1200	=item L<AnyEvent::FastPing>
872		1201
873	The fastest ping in the west.	1202	The fastest ping in the west.
874		1203
875	=item L<AnyEvent::DBI>
876
877	Executes L<DBI> requests asynchronously in a proxy process.
878
879	=item L<AnyEvent::AIO>
880
881	Truly asynchronous I/O, should be in the toolbox of every event
882	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
883	together.
884
885	=item L<AnyEvent::BDB>
886
887	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
888	L<BDB> and AnyEvent together.
889
890	=item L<AnyEvent::GPSD>
891
892	A non-blocking interface to gpsd, a daemon delivering GPS information.
893
894	=item L<AnyEvent::IGS>
895
896	A non-blocking interface to the Internet Go Server protocol (used by
897	L<App::IGS>).
898
899	=item L<AnyEvent::IRC>
900
901	AnyEvent based IRC client module family (replacing the older Net::IRC3).
902
903	=item L<Net::XMPP2>
904
905	AnyEvent based XMPP (Jabber protocol) module family.
906
907	=item L<Net::FCP>
908
909	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
910	of AnyEvent.
911
912	=item L<Event::ExecFlow>
913
914	High level API for event-based execution flow control.
915
916	=item L<Coro>	1204	=item L<Coro>
917		1205
918	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:
919		1208
920	=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";
921		1212
922	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	};
923		1219
924	=back	1220	=back
925		1221
926	=cut	1222	=cut
927		1223
928	package AnyEvent;	1224	package AnyEvent;
929		1225
930	no warnings;	1226	# basically a tuned-down version of common::sense
931	use strict qw(vars subs);	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	}
932		1233
		1234	BEGIN { AnyEvent::common_sense }
		1235
933	use Carp;	1236	use Carp ();
934		1237
935	our $VERSION = 4.4;	1238	our $VERSION = '6.02';
936	our $MODEL;	1239	our $MODEL;
937
938	our $AUTOLOAD;
939	our @ISA;	1240	our @ISA;
940
941	our @REGISTRY;	1241	our @REGISTRY;
942		1242	our $VERBOSE;
943	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!)
944		1245
945	BEGIN {	1246	BEGIN {
946	my $win32 = ! ! ($^O =~ /mswin32/i);	1247	require "AnyEvent/constants.pl";
947	eval "sub WIN32(){ $win32 }";
948	}
949		1248
950	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1249	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
951		1250
952	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1251	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1252	if ${^TAINT};
953		1253
954	{	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
955	my $idx;	1264	my $idx;
956	$PROTOCOL{$_} = ++$idx	1265	$PROTOCOL{$_} = ++$idx
957	for reverse split /\s*,\s*/,	1266	for reverse split /\s*,\s*/,
958	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1267	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
959	}	1268	}
960		1269
		1270	our @post_detect;
		1271
		1272	sub post_detect(&) {
		1273	my ($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
961	my @models = (	1347	our @models = (
962	[EV:: => AnyEvent::Impl::EV::],	1348	[EV:: => AnyEvent::Impl::EV::],
963	[Event:: => AnyEvent::Impl::Event::],
964	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1349	[AnyEvent::Loop:: => AnyEvent::Impl::Perl::],
965	# everything below here will not be autoprobed	1350	# everything below here will not (normally) be autoprobed
966	# as the pureperl backend should work everywhere	1351	# as the pure perl backend should work everywhere
967	# 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
968	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1358	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
969	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
970	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
971	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1359	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
972	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1360	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
973	[Wx:: => AnyEvent::Impl::POE::],	1361	[Wx:: => AnyEvent::Impl::POE::],
974	[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::],
975	);	1366	);
976		1367
977	our %method = map +($_ => 1),	1368	our @isa_hook;
		1369
		1370	sub _isa_set {
		1371	my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
		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, $reset_ae] : undef;
		1385
		1386	_isa_set;
		1387	}
		1388
		1389	# all autoloaded methods reserve the complete glob, not just the method slot.
		1390	# due to bugs in perls method cache implementation.
978	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1391	our @methods = qw(io timer time now now_update signal child idle condvar);
979		1392
980	our @post_detect;
981
982	sub post_detect(&) {	1393	sub detect() {
983	my ($cb) = @_;	1394	return $MODEL if $MODEL; # some programs keep references to detect
984		1395
985	if ($MODEL) {	1396	# IO::Async::Loop::AnyEvent is extremely evil, refuse to work with it
986	$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 - this module is broken by design,\n"
		1401	. "abuses internals and breaks AnyEvent, will not continue."
		1402	if exists $INC{"IO/Async/Loop/AnyEvent.pm"};
987		1403
988	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;
989	} else {	1423	} else {
990	push @post_detect, $cb;	1424	AnyEvent::log 4 => "unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
991		1425	}
992	defined wantarray
993	? bless \$cb, "AnyEvent::Util::postdetect"
994	: ()
995	}	1426	}
996	}
997		1427
998	sub AnyEvent::Util::postdetect::DESTROY {	1428	# check for already loaded models
999	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1000	}
1001
1002	sub detect() {
1003	unless ($MODEL) {	1429	unless ($MODEL) {
1004	no strict 'refs';	1430	for (@REGISTRY, @models) {
1005	local $SIG{__DIE__};	1431	my ($package, $model) = @$_;
1006		1432	if (${"$package\::VERSION"} > 0) {
1007	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1008	my $model = "AnyEvent::Impl::$1";
1009	if (eval "require $model") {	1433	if (eval "require $model") {
		1434	AnyEvent::log 7 => "autodetected model '$model', using it.";
1010	$MODEL = $model;	1435	$MODEL = $model;
1011	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1436	last;
1012	} else {	1437	}
1013	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;
1014	}	1438	}
1015	}	1439	}
1016		1440
1017	# check for already loaded models
1018	unless ($MODEL) {	1441	unless ($MODEL) {
		1442	# try to autoload a model
1019	for (@REGISTRY, @models) {	1443	for (@REGISTRY, @models) {
1020	my ($package, $model) = @$_;	1444	my ($package, $model) = @$_;
		1445	if (
		1446	eval "require $package"
1021	if (${"$package\::VERSION"} > 0) {	1447	and ${"$package\::VERSION"} > 0
1022	if (eval "require $model") {	1448	and eval "require $model"
		1449	) {
		1450	AnyEvent::log 7 => "autoloaded model '$model', using it.";
1023	$MODEL = $model;	1451	$MODEL = $model;
1024	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;
1025	last;	1452	last;
1026	}
1027	}	1453	}
1028	}	1454	}
1029		1455
1030	unless ($MODEL) {
1031	# try to load a model
1032
1033	for (@REGISTRY, @models) {
1034	my ($package, $model) = @$_;
1035	if (eval "require $package"
1036	and ${"$package\::VERSION"} > 0
1037	and eval "require $model") {
1038	$MODEL = $model;
1039	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1040	last;
1041	}
1042	}
1043
1044	$MODEL	1456	$MODEL
1045	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1457	or AnyEvent::log fatal => "AnyEvent: backend autodetection failed - did you properly install AnyEvent?";
1046	}
1047	}	1458	}
1048
1049	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1050
1051	unshift @ISA, $MODEL;
1052
1053	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1054
1055	(shift @post_detect)->() while @post_detect;
1056	}	1459	}
1057		1460
		1461	# free memory only needed for probing
		1462	undef @models;
		1463	undef @REGISTRY;
		1464
		1465	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1466
		1467	# now nuke some methods that are overridden by the backend.
		1468	# SUPER usage is not allowed in these.
		1469	for (qw(time signal child idle)) {
		1470	undef &{"AnyEvent::Base::$_"}
		1471	if defined &{"$MODEL\::$_"};
		1472	}
		1473
		1474	_isa_set;
		1475
		1476	# we're officially open!
		1477
		1478	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1479	require AnyEvent::Strict;
		1480	}
		1481
		1482	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1483	require AnyEvent::Debug;
		1484	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1485	}
		1486
		1487	if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1488	require AnyEvent::Socket;
		1489	require AnyEvent::Debug;
		1490
		1491	my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
		1492	$shell =~ s/\$\$/$$/g;
		1493
		1494	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1495	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1496	}
		1497
		1498	# now the anyevent environment is set up as the user told us to, so
		1499	# call the actual user code - post detects
		1500
		1501	(shift @post_detect)->() while @post_detect;
		1502	undef @post_detect;
		1503
		1504	*post_detect = sub(&) {
		1505	shift->();
		1506
		1507	undef
		1508	};
		1509
1058	$MODEL	1510	$MODEL
1059	}	1511	}
1060		1512
1061	sub AUTOLOAD {	1513	for my $name (@methods) {
1062	(my $func = $AUTOLOAD) =~ s/.*://;	1514	*$name = sub {
1063		1515	detect;
1064	$method{$func}	1516	# we use goto because
1065	or croak "$func: not a valid method for AnyEvent objects";	1517	# a) it makes the thunk more transparent
1066		1518	# b) it allows us to delete the thunk later
1067	detect unless $MODEL;	1519	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1068		1520	};
1069	my $class = shift;
1070	$class->$func (@_);
1071	}	1521	}
1072		1522
1073	# utility function to dup a filehandle. this is used by many backends	1523	# utility function to dup a filehandle. this is used by many backends
1074	# to support binding more than one watcher per filehandle (they usually	1524	# to support binding more than one watcher per filehandle (they usually
1075	# allow only one watcher per fd, so we dup it to get a different one).	1525	# allow only one watcher per fd, so we dup it to get a different one).
1076	sub _dupfh($$$$) {	1526	sub _dupfh($$;$$) {
1077	my ($poll, $fh, $r, $w) = @_;	1527	my ($poll, $fh, $r, $w) = @_;
1078		1528
1079	# cygwin requires the fh mode to be matching, unix doesn't	1529	# cygwin requires the fh mode to be matching, unix doesn't
1080	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1530	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1081	: $poll eq "w" ? ($w, ">")
1082	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1083		1531
1084	open my $fh2, "$mode&" . fileno $fh	1532	open my $fh2, $mode, $fh
1085	or die "cannot dup() filehandle: $!,";	1533	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1086		1534
1087	# we assume CLOEXEC is already set by perl in all important cases	1535	# we assume CLOEXEC is already set by perl in all important cases
1088		1536
1089	($fh2, $rw)	1537	($fh2, $rw)
1090	}	1538	}
1091		1539
		1540	=head1 SIMPLIFIED AE API
		1541
		1542	Starting with version 5.0, AnyEvent officially supports a second, much
		1543	simpler, API that is designed to reduce the calling, typing and memory
		1544	overhead by using function call syntax and a fixed number of parameters.
		1545
		1546	See the L<AE> manpage for details.
		1547
		1548	=cut
		1549
		1550	package AE;
		1551
		1552	our $VERSION = $AnyEvent::VERSION;
		1553
		1554	sub _reset() {
		1555	eval q{
		1556	# fall back to the main API by default - backends and AnyEvent::Base
		1557	# implementations can overwrite these.
		1558
		1559	sub io($$$) {
		1560	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1561	}
		1562
		1563	sub timer($$$) {
		1564	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1565	}
		1566
		1567	sub signal($$) {
		1568	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1569	}
		1570
		1571	sub child($$) {
		1572	AnyEvent->child (pid => $_[0], cb => $_[1])
		1573	}
		1574
		1575	sub idle($) {
		1576	AnyEvent->idle (cb => $_[0]);
		1577	}
		1578
		1579	sub cv(;&) {
		1580	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1581	}
		1582
		1583	sub now() {
		1584	AnyEvent->now
		1585	}
		1586
		1587	sub now_update() {
		1588	AnyEvent->now_update
		1589	}
		1590
		1591	sub time() {
		1592	AnyEvent->time
		1593	}
		1594
		1595	*postpone = \&AnyEvent::postpone;
		1596	*log = \&AnyEvent::log;
		1597	};
		1598	die if $@;
		1599	}
		1600
		1601	BEGIN { _reset }
		1602
1092	package AnyEvent::Base;	1603	package AnyEvent::Base;
1093		1604
1094	# default implementations for many methods	1605	# default implementations for many methods
1095		1606
1096	BEGIN {	1607	sub time {
		1608	eval q{ # poor man's autoloading {}
		1609	# probe for availability of Time::HiRes
1097	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1610	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1611	*time = sub { Time::HiRes::time () };
1098	*_time = \&Time::HiRes::time;	1612	*AE::time = \& Time::HiRes::time ;
		1613	*now = \&time;
		1614	AnyEvent::log 8 => "AnyEvent: using Time::HiRes for sub-second timing accuracy.";
1099	# if (eval "use POSIX (); (POSIX::times())...	1615	# if (eval "use POSIX (); (POSIX::times())...
1100	} else {	1616	} else {
1101	*_time = sub { time }; # epic fail	1617	*time = sub { CORE::time };
		1618	*AE::time = sub (){ CORE::time };
		1619	*now = \&time;
		1620	AnyEvent::log 3 => "using built-in time(), WARNING, no sub-second resolution!";
		1621	}
		1622	};
		1623	die if $@;
		1624
		1625	&time
		1626	}
		1627
		1628	*now = \&time;
		1629	sub now_update { }
		1630
		1631	sub _poll {
		1632	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1633	}
		1634
		1635	# default implementation for ->condvar
		1636	# in fact, the default should not be overwritten
		1637
		1638	sub condvar {
		1639	eval q{ # poor man's autoloading {}
		1640	*condvar = sub {
		1641	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1642	};
		1643
		1644	*AE::cv = sub (;&) {
		1645	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1646	};
		1647	};
		1648	die if $@;
		1649
		1650	&condvar
		1651	}
		1652
		1653	# default implementation for ->signal
		1654
		1655	our $HAVE_ASYNC_INTERRUPT;
		1656
		1657	sub _have_async_interrupt() {
		1658	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1659	&& eval "use Async::Interrupt 1.02 (); 1")
		1660	unless defined $HAVE_ASYNC_INTERRUPT;
		1661
		1662	$HAVE_ASYNC_INTERRUPT
		1663	}
		1664
		1665	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1666	our (%SIG_ASY, %SIG_ASY_W);
		1667	our ($SIG_COUNT, $SIG_TW);
		1668
		1669	# install a dummy wakeup watcher to reduce signal catching latency
		1670	# used by Impls
		1671	sub _sig_add() {
		1672	unless ($SIG_COUNT++) {
		1673	# try to align timer on a full-second boundary, if possible
		1674	my $NOW = AE::now;
		1675
		1676	$SIG_TW = AE::timer
		1677	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1678	$MAX_SIGNAL_LATENCY,
		1679	sub { } # just for the PERL_ASYNC_CHECK
		1680	;
1102	}	1681	}
1103	}	1682	}
1104		1683
1105	sub time { _time }	1684	sub _sig_del {
1106	sub now { _time }	1685	undef $SIG_TW
1107	sub now_update { }	1686	unless --$SIG_COUNT;
1108
1109	# default implementation for ->condvar
1110
1111	sub condvar {
1112	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1113	}	1687	}
1114		1688
1115	# default implementation for ->signal	1689	our $_sig_name_init; $_sig_name_init = sub {
		1690	eval q{ # poor man's autoloading {}
		1691	undef $_sig_name_init;
1116		1692
1117	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1693	if (_have_async_interrupt) {
		1694	*sig2num = \&Async::Interrupt::sig2num;
		1695	*sig2name = \&Async::Interrupt::sig2name;
		1696	} else {
		1697	require Config;
1118		1698
1119	sub _signal_exec {	1699	my %signame2num;
1120	sysread $SIGPIPE_R, my $dummy, 4;	1700	@signame2num{ split ' ', $Config::Config{sig_name} }
		1701	= split ' ', $Config::Config{sig_num};
1121		1702
1122	while (%SIG_EV) {	1703	my @signum2name;
1123	for (keys %SIG_EV) {	1704	@signum2name[values %signame2num] = keys %signame2num;
1124	delete $SIG_EV{$_};	1705
1125	$_->() for values %{ $SIG_CB{$_} || {} };	1706	*sig2num = sub($) {
		1707	$_[0] > 0 ? shift : $signame2num{+shift}
		1708	};
		1709	*sig2name = sub ($) {
		1710	$_[0] > 0 ? $signum2name[+shift] : shift
		1711	};
1126	}	1712	}
1127	}	1713	};
1128	}	1714	die if $@;
		1715	};
		1716
		1717	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1718	sub sig2name($) { &$_sig_name_init; &sig2name }
1129		1719
1130	sub signal {	1720	sub signal {
1131	my (undef, %arg) = @_;	1721	eval q{ # poor man's autoloading {}
		1722	# probe for availability of Async::Interrupt
		1723	if (_have_async_interrupt) {
		1724	AnyEvent::log 8 => "using Async::Interrupt for race-free signal handling.";
1132		1725
1133	unless ($SIGPIPE_R) {	1726	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1134	require Fcntl;	1727	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1135		1728
1136	if (AnyEvent::WIN32) {
1137	require AnyEvent::Util;
1138
1139	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1140	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1141	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1142	} else {	1729	} else {
		1730	AnyEvent::log 8 => "using emulated perl signal handling with latency timer.";
		1731
		1732	if (AnyEvent::WIN32) {
		1733	require AnyEvent::Util;
		1734
		1735	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1736	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1737	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1738	} else {
1143	pipe $SIGPIPE_R, $SIGPIPE_W;	1739	pipe $SIGPIPE_R, $SIGPIPE_W;
1144	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1740	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1145	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1741	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1742
		1743	# not strictly required, as $^F is normally 2, but let's make sure...
		1744	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1745	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1746	}
		1747
		1748	$SIGPIPE_R
		1749	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1750
		1751	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1146	}	1752	}
1147		1753
1148	$SIGPIPE_R	1754	*signal = $HAVE_ASYNC_INTERRUPT
1149	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1755	? sub {
		1756	my (undef, %arg) = @_;
1150		1757
1151	# not strictly required, as $^F is normally 2, but let's make sure...	1758	# async::interrupt
1152	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1153	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1154
1155	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1156	}
1157
1158	my $signal = uc $arg{signal}	1759	my $signal = sig2num $arg{signal};
1159	or Carp::croak "required option 'signal' is missing";
1160
1161	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1760	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1761
		1762	$SIG_ASY{$signal} ||= new Async::Interrupt
		1763	cb => sub { undef $SIG_EV{$signal} },
		1764	signal => $signal,
		1765	pipe => [$SIGPIPE_R->filenos],
		1766	pipe_autodrain => 0,
		1767	;
		1768
		1769	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1770	}
		1771	: sub {
		1772	my (undef, %arg) = @_;
		1773
		1774	# pure perl
		1775	my $signal = sig2name $arg{signal};
		1776	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1777
1162	$SIG{$signal} ||= sub {	1778	$SIG{$signal} ||= sub {
1163	local $!;	1779	local $!;
1164	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1780	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1165	undef $SIG_EV{$signal};	1781	undef $SIG_EV{$signal};
		1782	};
		1783
		1784	# can't do signal processing without introducing races in pure perl,
		1785	# so limit the signal latency.
		1786	_sig_add;
		1787
		1788	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1789	}
		1790	;
		1791
		1792	*AnyEvent::Base::signal::DESTROY = sub {
		1793	my ($signal, $cb) = @{$_[0]};
		1794
		1795	_sig_del;
		1796
		1797	delete $SIG_CB{$signal}{$cb};
		1798
		1799	$HAVE_ASYNC_INTERRUPT
		1800	? delete $SIG_ASY{$signal}
		1801	: # delete doesn't work with older perls - they then
		1802	# print weird messages, or just unconditionally exit
		1803	# instead of getting the default action.
		1804	undef $SIG{$signal}
		1805	unless keys %{ $SIG_CB{$signal} };
		1806	};
		1807
		1808	*_signal_exec = sub {
		1809	$HAVE_ASYNC_INTERRUPT
		1810	? $SIGPIPE_R->drain
		1811	: sysread $SIGPIPE_R, (my $dummy), 9;
		1812
		1813	while (%SIG_EV) {
		1814	for (keys %SIG_EV) {
		1815	delete $SIG_EV{$_};
		1816	&$_ for values %{ $SIG_CB{$_} || {} };
		1817	}
		1818	}
		1819	};
1166	};	1820	};
		1821	die if $@;
1167		1822
1168	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1823	&signal
1169	}
1170
1171	sub AnyEvent::Base::signal::DESTROY {
1172	my ($signal, $cb) = @{$_[0]};
1173
1174	delete $SIG_CB{$signal}{$cb};
1175
1176	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1177	}	1824	}
1178		1825
1179	# default implementation for ->child	1826	# default implementation for ->child
1180		1827
1181	our %PID_CB;	1828	our %PID_CB;
1182	our $CHLD_W;	1829	our $CHLD_W;
1183	our $CHLD_DELAY_W;	1830	our $CHLD_DELAY_W;
1184	our $PID_IDLE;
1185	our $WNOHANG;
1186		1831
1187	sub _child_wait {	1832	# used by many Impl's
1188	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1833	sub _emit_childstatus($$) {
		1834	my (undef, $rpid, $rstatus) = @_;
		1835
		1836	$_->($rpid, $rstatus)
1189	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1837	for values %{ $PID_CB{$rpid} || {} },
1190	(values %{ $PID_CB{0} || {} });	1838	values %{ $PID_CB{0} || {} };
1191	}
1192
1193	undef $PID_IDLE;
1194	}
1195
1196	sub _sigchld {
1197	# make sure we deliver these changes "synchronous" with the event loop.
1198	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
1199	undef $CHLD_DELAY_W;
1200	&_child_wait;
1201	});
1202	}	1839	}
1203		1840
1204	sub child {	1841	sub child {
		1842	eval q{ # poor man's autoloading {}
		1843	*_sigchld = sub {
		1844	my $pid;
		1845
		1846	AnyEvent->_emit_childstatus ($pid, $?)
		1847	while ($pid = waitpid -1, WNOHANG) > 0;
		1848	};
		1849
		1850	*child = sub {
1205	my (undef, %arg) = @_;	1851	my (undef, %arg) = @_;
1206		1852
1207	defined (my $pid = $arg{pid} + 0)	1853	my $pid = $arg{pid};
1208	or Carp::croak "required option 'pid' is missing";	1854	my $cb = $arg{cb};
1209		1855
1210	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1856	$PID_CB{$pid}{$cb+0} = $cb;
1211		1857
1212	unless ($WNOHANG) {
1213	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1214	}
1215
1216	unless ($CHLD_W) {	1858	unless ($CHLD_W) {
1217	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1859	$CHLD_W = AE::signal CHLD => \&_sigchld;
1218	# child could be a zombie already, so make at least one round	1860	# child could be a zombie already, so make at least one round
1219	&_sigchld;	1861	&_sigchld;
1220	}	1862	}
1221		1863
1222	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1864	bless [$pid, $cb+0], "AnyEvent::Base::child"
1223	}	1865	};
1224		1866
1225	sub AnyEvent::Base::child::DESTROY {	1867	*AnyEvent::Base::child::DESTROY = sub {
1226	my ($pid, $cb) = @{$_[0]};	1868	my ($pid, $icb) = @{$_[0]};
1227		1869
1228	delete $PID_CB{$pid}{$cb};	1870	delete $PID_CB{$pid}{$icb};
1229	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1871	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1230		1872
1231	undef $CHLD_W unless keys %PID_CB;	1873	undef $CHLD_W unless keys %PID_CB;
		1874	};
		1875	};
		1876	die if $@;
		1877
		1878	&child
1232	}	1879	}
1233		1880
1234	# idle emulation is done by simply using a timer, regardless	1881	# idle emulation is done by simply using a timer, regardless
1235	# of whether the proces sis idle or not, and not letting	1882	# of whether the process is idle or not, and not letting
1236	# the callback use more than 50% of the time.	1883	# the callback use more than 50% of the time.
1237	sub idle {	1884	sub idle {
		1885	eval q{ # poor man's autoloading {}
		1886	*idle = sub {
1238	my (undef, %arg) = @_;	1887	my (undef, %arg) = @_;
1239		1888
1240	my ($cb, $w, $rcb) = $arg{cb};	1889	my ($cb, $w, $rcb) = $arg{cb};
1241		1890
1242	$rcb = sub {	1891	$rcb = sub {
1243	if ($cb) {	1892	if ($cb) {
1244	$w = _time;	1893	$w = AE::time;
1245	&$cb;	1894	&$cb;
1246	$w = _time - $w;	1895	$w = AE::time - $w;
1247		1896
1248	# never use more then 50% of the time for the idle watcher,	1897	# never use more then 50% of the time for the idle watcher,
1249	# within some limits	1898	# within some limits
1250	$w = 0.0001 if $w < 0.0001;	1899	$w = 0.0001 if $w < 0.0001;
1251	$w = 5 if $w > 5;	1900	$w = 5 if $w > 5;
1252		1901
1253	$w = AnyEvent->timer (after => $w, cb => $rcb);	1902	$w = AE::timer $w, 0, $rcb;
1254	} else {	1903	} else {
1255	# clean up...	1904	# clean up...
1256	undef $w;	1905	undef $w;
1257	undef $rcb;	1906	undef $rcb;
		1907	}
		1908	};
		1909
		1910	$w = AE::timer 0.05, 0, $rcb;
		1911
		1912	bless \\$cb, "AnyEvent::Base::idle"
1258	}	1913	};
		1914
		1915	*AnyEvent::Base::idle::DESTROY = sub {
		1916	undef $${$_[0]};
		1917	};
1259	};	1918	};
		1919	die if $@;
1260		1920
1261	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1921	&idle
1262
1263	bless \\$cb, "AnyEvent::Base::idle"
1264	}
1265
1266	sub AnyEvent::Base::idle::DESTROY {
1267	undef $${$_[0]};
1268	}	1922	}
1269		1923
1270	package AnyEvent::CondVar;	1924	package AnyEvent::CondVar;
1271		1925
1272	our @ISA = AnyEvent::CondVar::Base::;	1926	our @ISA = AnyEvent::CondVar::Base::;
1273		1927
		1928	# only to be used for subclassing
		1929	sub new {
		1930	my $class = shift;
		1931	bless AnyEvent->condvar (@_), $class
		1932	}
		1933
1274	package AnyEvent::CondVar::Base;	1934	package AnyEvent::CondVar::Base;
1275		1935
1276	use overload	1936	#use overload
1277	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1937	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1278	fallback => 1;	1938	# fallback => 1;
		1939
		1940	# save 300+ kilobytes by dirtily hardcoding overloading
		1941	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1942	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1943	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1944	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1945
		1946	our $WAITING;
1279		1947
1280	sub _send {	1948	sub _send {
1281	# nop	1949	# nop
		1950	}
		1951
		1952	sub _wait {
		1953	AnyEvent->_poll until $_[0]{_ae_sent};
1282	}	1954	}
1283		1955
1284	sub send {	1956	sub send {
1285	my $cv = shift;	1957	my $cv = shift;
1286	$cv->{_ae_sent} = [@_];	1958	$cv->{_ae_sent} = [@_];
…		…
1295		1967
1296	sub ready {	1968	sub ready {
1297	$_[0]{_ae_sent}	1969	$_[0]{_ae_sent}
1298	}	1970	}
1299		1971
1300	sub _wait {
1301	AnyEvent->one_event while !$_[0]{_ae_sent};
1302	}
1303
1304	sub recv {	1972	sub recv {
		1973	unless ($_[0]{_ae_sent}) {
		1974	$WAITING
		1975	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1976
		1977	local $WAITING = 1;
1305	$_[0]->_wait;	1978	$_[0]->_wait;
		1979	}
1306		1980
1307	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1981	$_[0]{_ae_croak}
1308	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1982	and Carp::croak $_[0]{_ae_croak};
		1983
		1984	wantarray
		1985	? @{ $_[0]{_ae_sent} }
		1986	: $_[0]{_ae_sent}[0]
1309	}	1987	}
1310		1988
1311	sub cb {	1989	sub cb {
1312	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1990	my $cv = shift;
		1991
		1992	@_
		1993	and $cv->{_ae_cb} = shift
		1994	and $cv->{_ae_sent}
		1995	and (delete $cv->{_ae_cb})->($cv);
		1996
1313	$_[0]{_ae_cb}	1997	$cv->{_ae_cb}
1314	}	1998	}
1315		1999
1316	sub begin {	2000	sub begin {
1317	++$_[0]{_ae_counter};	2001	++$_[0]{_ae_counter};
1318	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	2002	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1323	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	2007	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1324	}	2008	}
1325		2009
1326	# undocumented/compatibility with pre-3.4	2010	# undocumented/compatibility with pre-3.4
1327	*broadcast = \&send;	2011	*broadcast = \&send;
1328	*wait = \&_wait;	2012	*wait = \&recv;
1329		2013
1330	=head1 ERROR AND EXCEPTION HANDLING	2014	=head1 ERROR AND EXCEPTION HANDLING
1331		2015
1332	In general, AnyEvent does not do any error handling - it relies on the	2016	In general, AnyEvent does not do any error handling - it relies on the
1333	caller to do that if required. The L<AnyEvent::Strict> module (see also	2017	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1345	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and	2029	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1346	so on.	2030	so on.
1347		2031
1348	=head1 ENVIRONMENT VARIABLES	2032	=head1 ENVIRONMENT VARIABLES
1349		2033
1350	The following environment variables are used by this module or its	2034	AnyEvent supports a number of environment variables that tune the
1351	submodules:	2035	runtime behaviour. They are usually evaluated when AnyEvent is
		2036	loaded, initialised, or a submodule that uses them is loaded. Many of
		2037	them also cause AnyEvent to load additional modules - for example,
		2038	C<PERL_ANYEVENT_DEBUG_WRAP> causes the L<AnyEvent::Debug> module to be
		2039	loaded.
		2040
		2041	All the environment variables documented here start with
		2042	C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
		2043	namespace. Other modules are encouraged (but by no means required) to use
		2044	C<PERL_ANYEVENT_SUBMODULE> if they have registered the AnyEvent::Submodule
		2045	namespace on CPAN, for any submodule. For example, L<AnyEvent::HTTP> could
		2046	be expected to use C<PERL_ANYEVENT_HTTP_PROXY> (it should not access env
		2047	variables starting with C<AE_>, see below).
		2048
		2049	All variables can also be set via the C<AE_> prefix, that is, instead
		2050	of setting C<PERL_ANYEVENT_VERBOSE> you can also set C<AE_VERBOSE>. In
		2051	case there is a clash btween anyevent and another program that uses
		2052	C<AE_something> you can set the corresponding C<PERL_ANYEVENT_something>
		2053	variable to the empty string, as those variables take precedence.
		2054
		2055	When AnyEvent is first loaded, it copies all C<AE_xxx> env variables
		2056	to their C<PERL_ANYEVENT_xxx> counterpart unless that variable already
		2057	exists. If taint mode is on, then AnyEvent will remove I<all> environment
		2058	variables starting with C<PERL_ANYEVENT_> from C<%ENV> (or replace them
		2059	with C<undef> or the empty string, if the corresaponding C<AE_> variable
		2060	is set).
		2061
		2062	The exact algorithm is currently:
		2063
		2064	1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
		2065	2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
		2066	3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
		2067
		2068	This ensures that child processes will not see the C<AE_> variables.
		2069
		2070	The following environment variables are currently known to AnyEvent:
1352		2071
1353	=over 4	2072	=over 4
1354		2073
1355	=item C<PERL_ANYEVENT_VERBOSE>	2074	=item C<PERL_ANYEVENT_VERBOSE>
1356		2075
1357	By default, AnyEvent will be completely silent except in fatal	2076	By default, AnyEvent will only log messages with loglevel C<3>
1358	conditions. You can set this environment variable to make AnyEvent more	2077	(C<critical>) or higher (see L<AnyEvent::Log>). You can set this
		2078	environment variable to a numerical loglevel to make AnyEvent more (or
1359	talkative.	2079	less) talkative.
1360		2080
		2081	If you want to do more than just set the global logging level
		2082	you should have a look at C<PERL_ANYEVENT_LOG>, which allows much more
		2083	complex specifications.
		2084
		2085	When set to C<0> (C<off>), then no messages whatsoever will be logged with
		2086	the default logging settings.
		2087
1361	When set to C<1> or higher, causes AnyEvent to warn about unexpected	2088	When set to C<5> or higher (C<warn>), causes AnyEvent to warn about
1362	conditions, such as not being able to load the event model specified by	2089	unexpected conditions, such as not being able to load the event model
1363	C<PERL_ANYEVENT_MODEL>.	2090	specified by C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an
		2091	exception - this is the minimum recommended level.
1364		2092
1365	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	2093	When set to C<7> or higher (info), cause AnyEvent to report which event model it
1366	model it chooses.	2094	chooses.
		2095
		2096	When set to C<8> or higher (debug), then AnyEvent will report extra information on
		2097	which optional modules it loads and how it implements certain features.
		2098
		2099	=item C<PERL_ANYEVENT_LOG>
		2100
		2101	Accepts rather complex logging specifications. For example, you could log
		2102	all C<debug> messages of some module to stderr, warnings and above to
		2103	stderr, and errors and above to syslog, with:
		2104
		2105	PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
		2106
		2107	For the rather extensive details, see L<AnyEvent::Log>.
		2108
		2109	This variable is evaluated when AnyEvent (or L<AnyEvent::Log>) is loaded,
		2110	so will take effect even before AnyEvent has initialised itself.
		2111
		2112	Note that specifying this environment variable causes the L<AnyEvent::Log>
		2113	module to be loaded, while C<PERL_ANYEVENT_VERBOSE> does not, so only
		2114	using the latter saves a few hundred kB of memory until the first message
		2115	is being logged.
1367		2116
1368	=item C<PERL_ANYEVENT_STRICT>	2117	=item C<PERL_ANYEVENT_STRICT>
1369		2118
1370	AnyEvent does not do much argument checking by default, as thorough	2119	AnyEvent does not do much argument checking by default, as thorough
1371	argument checking is very costly. Setting this variable to a true value	2120	argument checking is very costly. Setting this variable to a true value
1372	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	2121	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1373	check the arguments passed to most method calls. If it finds any problems	2122	check the arguments passed to most method calls. If it finds any problems,
1374	it will croak.	2123	it will croak.
1375		2124
1376	In other words, enables "strict" mode.	2125	In other words, enables "strict" mode.
1377		2126
1378	Unlike C<use strict>, it is definitely recommended ot keep it off in	2127	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1379	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	2128	>>, it is definitely recommended to keep it off in production. Keeping
1380	developing programs can be very useful, however.	2129	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		2130	can be very useful, however.
		2131
		2132	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		2133
		2134	If this env variable is nonempty, then its contents will be interpreted by
		2135	C<AnyEvent::Socket::parse_hostport> and C<AnyEvent::Debug::shell> (after
		2136	replacing every occurance of C<$$> by the process pid). The shell object
		2137	is saved in C<$AnyEvent::Debug::SHELL>.
		2138
		2139	This happens when the first watcher is created.
		2140
		2141	For example, to bind a debug shell on a unix domain socket in
		2142	F<< /tmp/debug<pid>.sock >>, you could use this:
		2143
		2144	PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
		2145	# connect with e.g.: socat readline /tmp/debug123.sock
		2146
		2147	Or to bind to tcp port 4545 on localhost:
		2148
		2149	PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog
		2150	# connect with e.g.: telnet localhost 4545
		2151
		2152	Note that creating sockets in F</tmp> or on localhost is very unsafe on
		2153	multiuser systems.
		2154
		2155	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		2156
		2157	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		2158	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
1381		2159
1382	=item C<PERL_ANYEVENT_MODEL>	2160	=item C<PERL_ANYEVENT_MODEL>
1383		2161
1384	This can be used to specify the event model to be used by AnyEvent, before	2162	This can be used to specify the event model to be used by AnyEvent, before
1385	auto detection and -probing kicks in. It must be a string consisting	2163	auto detection and -probing kicks in.
1386	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	2164
		2165	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		2166	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1387	and the resulting module name is loaded and if the load was successful,	2167	resulting module name is loaded and - if the load was successful - used as
1388	used as event model. If it fails to load AnyEvent will proceed with	2168	event model backend. If it fails to load then AnyEvent will proceed with
1389	auto detection and -probing.	2169	auto detection and -probing.
1390		2170
1391	This functionality might change in future versions.	2171	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		2172	nothing gets prepended and the module name is used as-is (hint: C<::> at
		2173	the end of a string designates a module name and quotes it appropriately).
1392		2174
1393	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	2175	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1394	could start your program like this:	2176	could start your program like this:
1395		2177
1396	PERL_ANYEVENT_MODEL=Perl perl ...	2178	PERL_ANYEVENT_MODEL=Perl perl ...
1397		2179
1398	=item C<PERL_ANYEVENT_PROTOCOLS>	2180	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
1414	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>	2196	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1415	- only support IPv4, never try to resolve or contact IPv6	2197	- only support IPv4, never try to resolve or contact IPv6
1416	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or	2198	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1417	IPv6, but prefer IPv6 over IPv4.	2199	IPv6, but prefer IPv6 over IPv4.
1418		2200
		2201	=item C<PERL_ANYEVENT_HOSTS>
		2202
		2203	This variable, if specified, overrides the F</etc/hosts> file used by
		2204	L<AnyEvent::Socket>C<::resolve_sockaddr>, i.e. hosts aliases will be read
		2205	from that file instead.
		2206
1419	=item C<PERL_ANYEVENT_EDNS0>	2207	=item C<PERL_ANYEVENT_EDNS0>
1420		2208
1421	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension	2209	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension for
1422	for DNS. This extension is generally useful to reduce DNS traffic, but	2210	DNS. This extension is generally useful to reduce DNS traffic, especially
1423	some (broken) firewalls drop such DNS packets, which is why it is off by	2211	when DNSSEC is involved, but some (broken) firewalls drop such DNS
1424	default.	2212	packets, which is why it is off by default.
1425		2213
1426	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce	2214	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1427	EDNS0 in its DNS requests.	2215	EDNS0 in its DNS requests.
1428		2216
1429	=item C<PERL_ANYEVENT_MAX_FORKS>	2217	=item C<PERL_ANYEVENT_MAX_FORKS>
1430		2218
1431	The maximum number of child processes that C<AnyEvent::Util::fork_call>	2219	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1432	will create in parallel.	2220	will create in parallel.
		2221
		2222	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		2223
		2224	The default value for the C<max_outstanding> parameter for the default DNS
		2225	resolver - this is the maximum number of parallel DNS requests that are
		2226	sent to the DNS server.
		2227
		2228	=item C<PERL_ANYEVENT_MAX_SIGNAL_LATENCY>
		2229
		2230	Perl has inherently racy signal handling (you can basically choose between
		2231	losing signals and memory corruption) - pure perl event loops (including
		2232	C<AnyEvent::Loop>, when C<Async::Interrupt> isn't available) therefore
		2233	have to poll regularly to avoid losing signals.
		2234
		2235	Some event loops are racy, but don't poll regularly, and some event loops
		2236	are written in C but are still racy. For those event loops, AnyEvent
		2237	installs a timer that regularly wakes up the event loop.
		2238
		2239	By default, the interval for this timer is C<10> seconds, but you can
		2240	override this delay with this environment variable (or by setting
		2241	the C<$AnyEvent::MAX_SIGNAL_LATENCY> variable before creating signal
		2242	watchers).
		2243
		2244	Lower values increase CPU (and energy) usage, higher values can introduce
		2245	long delays when reaping children or waiting for signals.
		2246
		2247	The L<AnyEvent::Async> module, if available, will be used to avoid this
		2248	polling (with most event loops).
		2249
		2250	=item C<PERL_ANYEVENT_RESOLV_CONF>
		2251
		2252	The absolute path to a F<resolv.conf>-style file to use instead of
		2253	F</etc/resolv.conf> (or the OS-specific configuration) in the default
		2254	resolver, or the empty string to select the default configuration.
		2255
		2256	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		2257
		2258	When neither C<ca_file> nor C<ca_path> was specified during
		2259	L<AnyEvent::TLS> context creation, and either of these environment
		2260	variables are nonempty, they will be used to specify CA certificate
		2261	locations instead of a system-dependent default.
		2262
		2263	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		2264
		2265	When these are set to C<1>, then the respective modules are not
		2266	loaded. Mostly good for testing AnyEvent itself.
1433		2267
1434	=back	2268	=back
1435		2269
1436	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	2270	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1437		2271
…		…
1495	warn "read: $input\n"; # output what has been read	2329	warn "read: $input\n"; # output what has been read
1496	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2330	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1497	},	2331	},
1498	);	2332	);
1499		2333
1500	my $time_watcher; # can only be used once
1501
1502	sub new_timer {
1503	$timer = AnyEvent->timer (after => 1, cb => sub {	2334	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1504	warn "timeout\n"; # print 'timeout' about every second	2335	warn "timeout\n"; # print 'timeout' at most every second
1505	&new_timer; # and restart the time
1506	});	2336	});
1507	}
1508
1509	new_timer; # create first timer
1510		2337
1511	$cv->recv; # wait until user enters /^q/i	2338	$cv->recv; # wait until user enters /^q/i
1512		2339
1513	=head1 REAL-WORLD EXAMPLE	2340	=head1 REAL-WORLD EXAMPLE
1514		2341
…		…
1587		2414
1588	The actual code goes further and collects all errors (C<die>s, exceptions)	2415	The actual code goes further and collects all errors (C<die>s, exceptions)
1589	that occurred during request processing. The C<result> method detects	2416	that occurred during request processing. The C<result> method detects
1590	whether an exception as thrown (it is stored inside the $txn object)	2417	whether an exception as thrown (it is stored inside the $txn object)
1591	and just throws the exception, which means connection errors and other	2418	and just throws the exception, which means connection errors and other
1592	problems get reported tot he code that tries to use the result, not in a	2419	problems get reported to the code that tries to use the result, not in a
1593	random callback.	2420	random callback.
1594		2421
1595	All of this enables the following usage styles:	2422	All of this enables the following usage styles:
1596		2423
1597	1. Blocking:	2424	1. Blocking:
…		…
1645	through AnyEvent. The benchmark creates a lot of timers (with a zero	2472	through AnyEvent. The benchmark creates a lot of timers (with a zero
1646	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2473	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1647	which it is), lets them fire exactly once and destroys them again.	2474	which it is), lets them fire exactly once and destroys them again.
1648		2475
1649	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2476	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1650	distribution.	2477	distribution. It uses the L<AE> interface, which makes a real difference
		2478	for the EV and Perl backends only.
1651		2479
1652	=head3 Explanation of the columns	2480	=head3 Explanation of the columns
1653		2481
1654	I<watcher> is the number of event watchers created/destroyed. Since	2482	I<watcher> is the number of event watchers created/destroyed. Since
1655	different event models feature vastly different performances, each event	2483	different event models feature vastly different performances, each event
…		…
1676	watcher.	2504	watcher.
1677		2505
1678	=head3 Results	2506	=head3 Results
1679		2507
1680	name watchers bytes create invoke destroy comment	2508	name watchers bytes create invoke destroy comment
1681	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2509	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1682	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2510	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1683	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2511	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1684	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2512	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1685	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2513	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1686	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2514	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2515	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2516	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1687	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2517	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1688	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2518	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1689	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2519	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1690	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2520	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1691		2521
1692	=head3 Discussion	2522	=head3 Discussion
1693		2523
1694	The benchmark does I<not> measure scalability of the event loop very	2524	The benchmark does I<not> measure scalability of the event loop very
1695	well. For example, a select-based event loop (such as the pure perl one)	2525	well. For example, a select-based event loop (such as the pure perl one)
…		…
1707	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2537	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1708	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2538	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1709	cycles with POE.	2539	cycles with POE.
1710		2540
1711	C<EV> is the sole leader regarding speed and memory use, which are both	2541	C<EV> is the sole leader regarding speed and memory use, which are both
1712	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2542	maximal/minimal, respectively. When using the L<AE> API there is zero
		2543	overhead (when going through the AnyEvent API create is about 5-6 times
		2544	slower, with other times being equal, so still uses far less memory than
1713	far less memory than any other event loop and is still faster than Event	2545	any other event loop and is still faster than Event natively).
1714	natively.
1715		2546
1716	The pure perl implementation is hit in a few sweet spots (both the	2547	The pure perl implementation is hit in a few sweet spots (both the
1717	constant timeout and the use of a single fd hit optimisations in the perl	2548	constant timeout and the use of a single fd hit optimisations in the perl
1718	interpreter and the backend itself). Nevertheless this shows that it	2549	interpreter and the backend itself). Nevertheless this shows that it
1719	adds very little overhead in itself. Like any select-based backend its	2550	adds very little overhead in itself. Like any select-based backend its
1720	performance becomes really bad with lots of file descriptors (and few of	2551	performance becomes really bad with lots of file descriptors (and few of
1721	them active), of course, but this was not subject of this benchmark.	2552	them active), of course, but this was not subject of this benchmark.
1722		2553
1723	The C<Event> module has a relatively high setup and callback invocation	2554	The C<Event> module has a relatively high setup and callback invocation
1724	cost, but overall scores in on the third place.	2555	cost, but overall scores in on the third place.
		2556
		2557	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2558	when using its pure perl backend.
1725		2559
1726	C<Glib>'s memory usage is quite a bit higher, but it features a	2560	C<Glib>'s memory usage is quite a bit higher, but it features a
1727	faster callback invocation and overall ends up in the same class as	2561	faster callback invocation and overall ends up in the same class as
1728	C<Event>. However, Glib scales extremely badly, doubling the number of	2562	C<Event>. However, Glib scales extremely badly, doubling the number of
1729	watchers increases the processing time by more than a factor of four,	2563	watchers increases the processing time by more than a factor of four,
…		…
1764	(even when used without AnyEvent), but most event loops have acceptable	2598	(even when used without AnyEvent), but most event loops have acceptable
1765	performance with or without AnyEvent.	2599	performance with or without AnyEvent.
1766		2600
1767	=item * The overhead AnyEvent adds is usually much smaller than the overhead of	2601	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
1768	the actual event loop, only with extremely fast event loops such as EV	2602	the actual event loop, only with extremely fast event loops such as EV
1769	adds AnyEvent significant overhead.	2603	does AnyEvent add significant overhead.
1770		2604
1771	=item * You should avoid POE like the plague if you want performance or	2605	=item * You should avoid POE like the plague if you want performance or
1772	reasonable memory usage.	2606	reasonable memory usage.
1773		2607
1774	=back	2608	=back
…		…
1790	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2624	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1791	(1%) are active. This mirrors the activity of large servers with many	2625	(1%) are active. This mirrors the activity of large servers with many
1792	connections, most of which are idle at any one point in time.	2626	connections, most of which are idle at any one point in time.
1793		2627
1794	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2628	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1795	distribution.	2629	distribution. It uses the L<AE> interface, which makes a real difference
		2630	for the EV and Perl backends only.
1796		2631
1797	=head3 Explanation of the columns	2632	=head3 Explanation of the columns
1798		2633
1799	I<sockets> is the number of sockets, and twice the number of "servers" (as	2634	I<sockets> is the number of sockets, and twice the number of "servers" (as
1800	each server has a read and write socket end).	2635	each server has a read and write socket end).
…		…
1807	it to another server. This includes deleting the old timeout and creating	2642	it to another server. This includes deleting the old timeout and creating
1808	a new one that moves the timeout into the future.	2643	a new one that moves the timeout into the future.
1809		2644
1810	=head3 Results	2645	=head3 Results
1811		2646
1812	name sockets create request	2647	name sockets create request
1813	EV 20000 69.01 11.16	2648	EV 20000 62.66 7.99
1814	Perl 20000 73.32 35.87	2649	Perl 20000 68.32 32.64
1815	Event 20000 212.62 257.32	2650	IOAsync 20000 174.06 101.15 epoll
1816	Glib 20000 651.16 1896.30	2651	IOAsync 20000 174.67 610.84 poll
		2652	Event 20000 202.69 242.91
		2653	Glib 20000 557.01 1689.52
1817	POE 20000 349.67 12317.24 uses POE::Loop::Event	2654	POE 20000 341.54 12086.32 uses POE::Loop::Event
1818		2655
1819	=head3 Discussion	2656	=head3 Discussion
1820		2657
1821	This benchmark I<does> measure scalability and overall performance of the	2658	This benchmark I<does> measure scalability and overall performance of the
1822	particular event loop.	2659	particular event loop.
…		…
1824	EV is again fastest. Since it is using epoll on my system, the setup time	2661	EV is again fastest. Since it is using epoll on my system, the setup time
1825	is relatively high, though.	2662	is relatively high, though.
1826		2663
1827	Perl surprisingly comes second. It is much faster than the C-based event	2664	Perl surprisingly comes second. It is much faster than the C-based event
1828	loops Event and Glib.	2665	loops Event and Glib.
		2666
		2667	IO::Async performs very well when using its epoll backend, and still quite
		2668	good compared to Glib when using its pure perl backend.
1829		2669
1830	Event suffers from high setup time as well (look at its code and you will	2670	Event suffers from high setup time as well (look at its code and you will
1831	understand why). Callback invocation also has a high overhead compared to	2671	understand why). Callback invocation also has a high overhead compared to
1832	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2672	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1833	uses select or poll in basically all documented configurations.	2673	uses select or poll in basically all documented configurations.
…		…
1896	=item * C-based event loops perform very well with small number of	2736	=item * C-based event loops perform very well with small number of
1897	watchers, as the management overhead dominates.	2737	watchers, as the management overhead dominates.
1898		2738
1899	=back	2739	=back
1900		2740
		2741	=head2 THE IO::Lambda BENCHMARK
		2742
		2743	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2744	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2745	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2746	shouldn't come as a surprise to anybody). As such, the benchmark is
		2747	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2748	very optimal. But how would AnyEvent compare when used without the extra
		2749	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2750
		2751	The benchmark itself creates an echo-server, and then, for 500 times,
		2752	connects to the echo server, sends a line, waits for the reply, and then
		2753	creates the next connection. This is a rather bad benchmark, as it doesn't
		2754	test the efficiency of the framework or much non-blocking I/O, but it is a
		2755	benchmark nevertheless.
		2756
		2757	name runtime
		2758	Lambda/select 0.330 sec
		2759	+ optimized 0.122 sec
		2760	Lambda/AnyEvent 0.327 sec
		2761	+ optimized 0.138 sec
		2762	Raw sockets/select 0.077 sec
		2763	POE/select, components 0.662 sec
		2764	POE/select, raw sockets 0.226 sec
		2765	POE/select, optimized 0.404 sec
		2766
		2767	AnyEvent/select/nb 0.085 sec
		2768	AnyEvent/EV/nb 0.068 sec
		2769	+state machine 0.134 sec
		2770
		2771	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2772	benchmarks actually make blocking connects and use 100% blocking I/O,
		2773	defeating the purpose of an event-based solution. All of the newly
		2774	written AnyEvent benchmarks use 100% non-blocking connects (using
		2775	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2776	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2777	generally require a lot more bookkeeping and event handling than blocking
		2778	connects (which involve a single syscall only).
		2779
		2780	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2781	offers similar expressive power as POE and IO::Lambda, using conventional
		2782	Perl syntax. This means that both the echo server and the client are 100%
		2783	non-blocking, further placing it at a disadvantage.
		2784
		2785	As you can see, the AnyEvent + EV combination even beats the
		2786	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2787	backend easily beats IO::Lambda and POE.
		2788
		2789	And even the 100% non-blocking version written using the high-level (and
		2790	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2791	higher level ("unoptimised") abstractions by a large margin, even though
		2792	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
		2793
		2794	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2795	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2796	part of the IO::Lambda distribution and were used without any changes.
		2797
1901		2798
1902	=head1 SIGNALS	2799	=head1 SIGNALS
1903		2800
1904	AnyEvent currently installs handlers for these signals:	2801	AnyEvent currently installs handlers for these signals:
1905		2802
…		…
1908	=item SIGCHLD	2805	=item SIGCHLD
1909		2806
1910	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2807	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1911	emulation for event loops that do not support them natively. Also, some	2808	emulation for event loops that do not support them natively. Also, some
1912	event loops install a similar handler.	2809	event loops install a similar handler.
		2810
		2811	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2812	AnyEvent will reset it to default, to avoid losing child exit statuses.
1913		2813
1914	=item SIGPIPE	2814	=item SIGPIPE
1915		2815
1916	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2816	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1917	when AnyEvent gets loaded.	2817	when AnyEvent gets loaded.
…		…
1929		2829
1930	=back	2830	=back
1931		2831
1932	=cut	2832	=cut
1933		2833
		2834	undef $SIG{CHLD}
		2835	if $SIG{CHLD} eq 'IGNORE';
		2836
1934	$SIG{PIPE} = sub { }	2837	$SIG{PIPE} = sub { }
1935	unless defined $SIG{PIPE};	2838	unless defined $SIG{PIPE};
1936		2839
		2840	=head1 RECOMMENDED/OPTIONAL MODULES
		2841
		2842	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2843	its built-in modules) are required to use it.
		2844
		2845	That does not mean that AnyEvent won't take advantage of some additional
		2846	modules if they are installed.
		2847
		2848	This section explains which additional modules will be used, and how they
		2849	affect AnyEvent's operation.
		2850
		2851	=over 4
		2852
		2853	=item L<Async::Interrupt>
		2854
		2855	This slightly arcane module is used to implement fast signal handling: To
		2856	my knowledge, there is no way to do completely race-free and quick
		2857	signal handling in pure perl. To ensure that signals still get
		2858	delivered, AnyEvent will start an interval timer to wake up perl (and
		2859	catch the signals) with some delay (default is 10 seconds, look for
		2860	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2861
		2862	If this module is available, then it will be used to implement signal
		2863	catching, which means that signals will not be delayed, and the event loop
		2864	will not be interrupted regularly, which is more efficient (and good for
		2865	battery life on laptops).
		2866
		2867	This affects not just the pure-perl event loop, but also other event loops
		2868	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2869
		2870	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2871	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2872	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2873	does nothing for those backends.
		2874
		2875	=item L<EV>
		2876
		2877	This module isn't really "optional", as it is simply one of the backend
		2878	event loops that AnyEvent can use. However, it is simply the best event
		2879	loop available in terms of features, speed and stability: It supports
		2880	the AnyEvent API optimally, implements all the watcher types in XS, does
		2881	automatic timer adjustments even when no monotonic clock is available,
		2882	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2883	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2884	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2885
		2886	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2887	then this module will do nothing for you.
		2888
		2889	=item L<Guard>
		2890
		2891	The guard module, when used, will be used to implement
		2892	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2893	lot less memory), but otherwise doesn't affect guard operation much. It is
		2894	purely used for performance.
		2895
		2896	=item L<JSON> and L<JSON::XS>
		2897
		2898	One of these modules is required when you want to read or write JSON data
		2899	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2900	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2901
		2902	=item L<Net::SSLeay>
		2903
		2904	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2905	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2906	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2907
		2908	=item L<Time::HiRes>
		2909
		2910	This module is part of perl since release 5.008. It will be used when the
		2911	chosen event library does not come with a timing source of its own. The
		2912	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
		2913	try to use a monotonic clock for timing stability.
		2914
		2915	=back
		2916
1937		2917
1938	=head1 FORK	2918	=head1 FORK
1939		2919
1940	Most event libraries are not fork-safe. The ones who are usually are	2920	Most event libraries are not fork-safe. The ones who are usually are
1941	because they rely on inefficient but fork-safe C<select> or C<poll>	2921	because they rely on inefficient but fork-safe C<select> or C<poll> calls
1942	calls. Only L<EV> is fully fork-aware.	2922	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2923	are usually badly thought-out hacks that are incompatible with fork in
		2924	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2925	continue event-processing in both parent and child (or both, if you know
		2926	what you are doing).
		2927
		2928	This means that, in general, you cannot fork and do event processing in
		2929	the child if the event library was initialised before the fork (which
		2930	usually happens when the first AnyEvent watcher is created, or the library
		2931	is loaded).
1943		2932
1944	If you have to fork, you must either do so I<before> creating your first	2933	If you have to fork, you must either do so I<before> creating your first
1945	watcher OR you must not use AnyEvent at all in the child.	2934	watcher OR you must not use AnyEvent at all in the child OR you must do
		2935	something completely out of the scope of AnyEvent.
		2936
		2937	The problem of doing event processing in the parent I<and> the child
		2938	is much more complicated: even for backends that I<are> fork-aware or
		2939	fork-safe, their behaviour is not usually what you want: fork clones all
		2940	watchers, that means all timers, I/O watchers etc. are active in both
		2941	parent and child, which is almost never what you want. USing C<exec>
		2942	to start worker children from some kind of manage rprocess is usually
		2943	preferred, because it is much easier and cleaner, at the expense of having
		2944	to have another binary.
1946		2945
1947		2946
1948	=head1 SECURITY CONSIDERATIONS	2947	=head1 SECURITY CONSIDERATIONS
1949		2948
1950	AnyEvent can be forced to load any event model via	2949	AnyEvent can be forced to load any event model via
…		…
1962	use AnyEvent;	2961	use AnyEvent;
1963		2962
1964	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2963	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1965	be used to probe what backend is used and gain other information (which is	2964	be used to probe what backend is used and gain other information (which is
1966	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2965	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1967	$ENV{PERL_ANYEGENT_STRICT}.	2966	$ENV{PERL_ANYEVENT_STRICT}.
		2967
		2968	Note that AnyEvent will remove I<all> environment variables starting with
		2969	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2970	enabled.
1968		2971
1969		2972
1970	=head1 BUGS	2973	=head1 BUGS
1971		2974
1972	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2975	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
…		…
1976	pronounced).	2979	pronounced).
1977		2980
1978		2981
1979	=head1 SEE ALSO	2982	=head1 SEE ALSO
1980		2983
1981	Utility functions: L<AnyEvent::Util>.	2984	Tutorial/Introduction: L<AnyEvent::Intro>.
1982		2985
1983	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2986	FAQ: L<AnyEvent::FAQ>.
1984	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2987
		2988	Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
		2989	(simply logging).
		2990
		2991	Development/Debugging: L<AnyEvent::Strict> (stricter checking),
		2992	L<AnyEvent::Debug> (interactive shell, watcher tracing).
		2993
		2994	Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
		2995	L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
		2996	L<Qt>, L<POE>, L<FLTK>.
1985		2997
1986	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2998	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1987	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2999	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1988	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	3000	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
		3001	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
1989	L<AnyEvent::Impl::POE>.	3002	L<AnyEvent::Impl::FLTK>.
1990		3003
1991	Non-blocking file handles, sockets, TCP clients and	3004	Non-blocking handles, pipes, stream sockets, TCP clients and
1992	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	3005	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1993		3006
1994	Asynchronous DNS: L<AnyEvent::DNS>.	3007	Asynchronous DNS: L<AnyEvent::DNS>.
1995		3008
1996	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	3009	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
1997		3010
1998	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	3011	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
		3012	L<AnyEvent::HTTP>.
1999		3013
2000		3014
2001	=head1 AUTHOR	3015	=head1 AUTHOR
2002		3016
2003	Marc Lehmann <schmorp@schmorp.de>	3017	Marc Lehmann <schmorp@schmorp.de>

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