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Revision 1.395 by root, Tue Jan 31 19:03:16 2012 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - the DBI of event loop programming	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt,
6	and POE are various supported event loops/environments.	6	FLTK and POE are various supported event loops/environments.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
12	# file descriptor readable	15	# file handle or descriptor readable
13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14		17
15	# one-shot or repeating timers	18	# one-shot or repeating timers
16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
18		21
19	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
21		24
22	# POSIX signal	25	# POSIX signal
…		…
43	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
44	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
45		48
46	=head1 SUPPORT	49	=head1 SUPPORT
47		50
		51	An FAQ document is available as L<AnyEvent::FAQ>.
		52
48	There is a mailinglist for discussing all things AnyEvent, and an IRC	53	There also is a mailinglist for discussing all things AnyEvent, and an IRC
49	channel, too.	54	channel, too.
50		55
51	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software	56	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
52	Repository>, at L<http://anyevent.schmorp.de>, for more info.	57	Repository>, at L<http://anyevent.schmorp.de>, for more info.
53		58
…		…
73	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
74	model you use.	79	model you use.
75		80
76	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
77	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
78	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
79	cannot use anything else, as they are simply incompatible to everything	84	cannot use anything else, as they are simply incompatible to everything
80	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
81	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.
82		87
83	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	88	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
84	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
85	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
86	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
87	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
88	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
89	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,
90	to AnyEvent, too, so it is future-proof).	95	so it is future-proof).
91		96
92	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
93	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
94	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
95	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
96	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
97	technically possible.	102	technically possible.
98		103
99	Of course, AnyEvent comes with a big (and fully optional!) toolbox	104	Of course, AnyEvent comes with a big (and fully optional!) toolbox
100	of useful functionality, such as an asynchronous DNS resolver, 100%	105	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
106	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
107	model, you should I<not> use this module.	112	model, you should I<not> use this module.
108		113
109	=head1 DESCRIPTION	114	=head1 DESCRIPTION
110		115
111	L<AnyEvent> provides an identical interface to multiple event loops. This	116	L<AnyEvent> provides a uniform interface to various event loops. This
112	allows module authors to utilise an event loop without forcing module	117	allows module authors to use event loop functionality without forcing
113	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
114	peacefully at any one time).	119	than one event loop cannot coexist peacefully).
115		120
116	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>
117	module.	122	module.
118		123
119	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
120	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
121	following modules is already loaded: L<EV>,	126	following modules is already loaded: L<EV>, L<AnyEvent::Loop>,
122	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
123	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
124	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
125	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
126	be successfully loaded will be used. If, after this, still none could be	131	the other two are not normally tried.
127	found, AnyEvent will fall back to a pure-perl event loop, which is not
128	very efficient, but should work everywhere.
129		132
130	Because AnyEvent first checks for modules that are already loaded, loading	133	Because AnyEvent first checks for modules that are already loaded, loading
131	an event model explicitly before first using AnyEvent will likely make	134	an event model explicitly before first using AnyEvent will likely make
132	that model the default. For example:	135	that model the default. For example:
133		136
…		…
135	use AnyEvent;	138	use AnyEvent;
136		139
137	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
138		141
139	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
140	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,
141	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
142		146
143	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called C<AnyEvent::Loop>. Like
144	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
145	explicitly and enjoy the high availability of that event loop :)	149	availability of that event loop :)
146		150
147	=head1 WATCHERS	151	=head1 WATCHERS
148		152
149	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
150	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
…		…
155	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
156	is in control).	160	is in control).
157		161
158	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
159	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<<
160	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
161	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
162	widely between event loops.	166	widely between event loops.
163		167
164	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
165	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
166	to it).	170	to it).
167		171
168	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.
169		173
170	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
171	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.
172		176
173	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
174		178
175	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
176	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
177	undef $w;	181	undef $w;
178	});	182	});
…		…
210		214
211	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.
212	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
213	underlying file descriptor.	217	underlying file descriptor.
214		218
215	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
216	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
217	handles.	221	handles.
218		222
219	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
220	watcher.	224	watcher.
…		…
244		248
245	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
246	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
247	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
248		252
249	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
250	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
251	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
252	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
253	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.
254		258
255	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
256	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
257	only approximate.	261	only approximate.
258		262
259	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
260		264
261	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
279		283
280	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
281	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
282	"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
283	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
284	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.
285		289
286	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
287	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
288	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)
289	timers.	293	timers.
290		294
291	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
292	AnyEvent API.	296	AnyEvent API.
…		…
314	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
315	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
316		320
317	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
318	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
319	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
320		324
321	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
322	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
323		327
324	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>
325	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
326		330
327	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
328	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
329	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
330	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
331	after three seconds.	335	after three seconds.
332		336
…		…
352	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	356	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
353	account.	357	account.
354		358
355	=item AnyEvent->now_update	359	=item AnyEvent->now_update
356		360
357	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
358	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 >>,
359	AnyEvent->now >>, above).	363	above).
360		364
361	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
362	this "current" time will differ substantially from the real time, which	366	this "current" time will differ substantially from the real time, which
363	might affect timers and time-outs.	367	might affect timers and time-outs.
364		368
…		…
403		407
404	Example: exit on SIGINT	408	Example: exit on SIGINT
405		409
406	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
407		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling)
		421	or "unsafe" (asynchronous) - the former might delay signal delivery
		422	indefinitely, the latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
408	=head3 Signal Races, Delays and Workarounds	429	=head3 Signal Races, Delays and Workarounds
409		430
410	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching	431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support
411	callbacks to signals in a generic way, which is a pity, as you cannot	432	attaching callbacks to signals in a generic way, which is a pity,
412	do race-free signal handling in perl, requiring C libraries for	433	as you cannot do race-free signal handling in perl, requiring
413	this. AnyEvent will try to do it's best, which means in some cases,	434	C libraries for this. AnyEvent will try to do its best, which
414	signals will be delayed. The maximum time a signal might be delayed is	435	means in some cases, signals will be delayed. The maximum time
415	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This	436	a signal might be delayed is 10 seconds by default, but can
416	variable can be changed only before the first signal watcher is created,	437	be overriden via C<$ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY}> or
417	and should be left alone otherwise. This variable determines how often	438	C<$AnyEvent::MAX_SIGNAL_LATENCY> - see the Ö<ENVIRONMENT VARIABLES>
418	AnyEvent polls for signals (in case a wake-up was missed). Higher values	439	section for details.
419	will cause fewer spurious wake-ups, which is better for power and CPU
420	saving.
421		440
422	All these problems can be avoided by installing the optional	441	All these problems can be avoided by installing the optional
423	L<Async::Interrupt> module, which works with most event loops. It will not	442	L<Async::Interrupt> module, which works with most event loops. It will not
424	work with inherently broken event loops such as L<Event> or L<Event::Lib>	443	work with inherently broken event loops such as L<Event> or L<Event::Lib>
425	(and not with L<POE> currently, as POE does it's own workaround with	444	(and not with L<POE> currently). For those, you just have to suffer the
426	one-second latency). For those, you just have to suffer the delays.	445	delays.
427		446
428	=head2 CHILD PROCESS WATCHERS	447	=head2 CHILD PROCESS WATCHERS
429		448
430	$w = AnyEvent->child (pid => <process id>, cb => <callback>);	449	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
431		450
432	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.
433		452
434	The child process is specified by the C<pid> argument (one some backends,	453	The child process is specified by the C<pid> argument (on some backends,
435	using C<0> watches for any child process exit, on others this will	454	using C<0> watches for any child process exit, on others this will
436	croak). The watcher will be triggered only when the child process has	455	croak). The watcher will be triggered only when the child process has
437	finished and an exit status is available, not on any trace events	456	finished and an exit status is available, not on any trace events
438	(stopped/continued).	457	(stopped/continued).
439		458
…		…
461	thing in an AnyEvent program, you I<have> to create at least one	480	thing in an AnyEvent program, you I<have> to create at least one
462	watcher before you C<fork> the child (alternatively, you can call	481	watcher before you C<fork> the child (alternatively, you can call
463	C<AnyEvent::detect>).	482	C<AnyEvent::detect>).
464		483
465	As most event loops do not support waiting for child events, they will be	484	As most event loops do not support waiting for child events, they will be
466	emulated by AnyEvent in most cases, in which the latency and race problems	485	emulated by AnyEvent in most cases, in which case the latency and race
467	mentioned in the description of signal watchers apply.	486	problems mentioned in the description of signal watchers apply.
468		487
469	Example: fork a process and wait for it	488	Example: fork a process and wait for it
470		489
471	my $done = AnyEvent->condvar;	490	my $done = AnyEvent->condvar;
472		491
…		…
486		505
487	=head2 IDLE WATCHERS	506	=head2 IDLE WATCHERS
488		507
489	$w = AnyEvent->idle (cb => <callback>);	508	$w = AnyEvent->idle (cb => <callback>);
490		509
491	Sometimes there is a need to do something, but it is not so important	510	This will repeatedly invoke the callback after the process becomes idle,
492	to do it instantly, but only when there is nothing better to do. This	511	until either the watcher is destroyed or new events have been detected.
493	"nothing better to do" is usually defined to be "no other events need
494	attention by the event loop".
495		512
496	Idle watchers ideally get invoked when the event loop has nothing	513	Idle watchers are useful when there is a need to do something, but it
497	better to do, just before it would block the process to wait for new	514	is not so important (or wise) to do it instantly. The callback will be
498	events. Instead of blocking, the idle watcher is invoked.	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.
499		521
500	Most event loops unfortunately do not really support idle watchers (only	522	Unfortunately, most event loops do not really support idle watchers (only
501	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
502	will simply call the callback "from time to time".	524	will simply call the callback "from time to time".
503		525
504	Example: read lines from STDIN, but only process them when the	526	Example: read lines from STDIN, but only process them when the
505	program is otherwise idle:	527	program is otherwise idle:
…		…
533	will actively watch for new events and call your callbacks.	555	will actively watch for new events and call your callbacks.
534		556
535	AnyEvent is slightly different: it expects somebody else to run the event	557	AnyEvent is slightly different: it expects somebody else to run the event
536	loop and 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).
537		559
538	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
539	because they represent a condition that must become true.	561	they represent a condition that must become true.
540		562
541	Now is probably a good time to look at the examples further below.	563	Now is probably a good time to look at the examples further below.
542		564
543	Condition variables can be created by calling the C<< AnyEvent->condvar	565	Condition variables can be created by calling the C<< AnyEvent->condvar
544	>> method, usually without arguments. The only argument pair allowed is	566	>> method, usually without arguments. The only argument pair allowed is
…		…
549	After creation, the condition variable is "false" until it becomes "true"	571	After creation, the condition variable is "false" until it becomes "true"
550	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
551	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<<
552	->send >> method).	574	->send >> method).
553		575
554	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
555	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:
556	in time where multiple outstanding events have been processed. And yet	578
557	another way to call them is transactions - each condition variable can be	579	=over 4
558	used to represent a transaction, which finishes at some point and delivers	580
559	a result. And yet some people know them as "futures" - a promise to	581	=item * Condition variables are like callbacks - you can call them (and pass them instead
560	compute/deliver something that you can wait for.	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
561		599
562	Condition variables are very useful to signal that something has finished,	600	Condition variables are very useful to signal that something has finished,
563	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,
564	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
565	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
…		…
578		616
579	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
580	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
581	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
582	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
583	it's C<new> method in your own C<new> method.	621	its C<new> method in your own C<new> method.
584		622
585	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
586	eventually calls C<< -> send >>, and the "consumer side", which waits	624	eventually calls C<< -> send >>, and the "consumer side", which waits
587	for the send to occur.	625	for the send to occur.
588		626
589	Example: wait for a timer.	627	Example: wait for a timer.
590		628
591	# wait till the result is ready	629	# condition: "wait till the timer is fired"
592	my $result_ready = AnyEvent->condvar;	630	my $timer_fired = AnyEvent->condvar;
593		631
594	# do something such as adding a timer	632	# create the timer - we could wait for, say
595	# or socket watcher the calls $result_ready->send	633	# a handle becomign ready, or even an
596	# when the "result" is ready.	634	# AnyEvent::HTTP request to finish, but
597	# in this case, we simply use a timer:	635	# in this case, we simply use a timer:
598	my $w = AnyEvent->timer (	636	my $w = AnyEvent->timer (
599	after => 1,	637	after => 1,
600	cb => sub { $result_ready->send },	638	cb => sub { $timer_fired->send },
601	);	639	);
602		640
603	# this "blocks" (while handling events) till the callback	641	# this "blocks" (while handling events) till the callback
604	# calls ->send	642	# calls ->send
605	$result_ready->recv;	643	$timer_fired->recv;
606		644
607	Example: wait for a timer, but take advantage of the fact that condition	645	Example: wait for a timer, but take advantage of the fact that condition
608	variables are also callable directly.	646	variables are also callable directly.
609		647
610	my $done = AnyEvent->condvar;	648	my $done = AnyEvent->condvar;
…		…
653	they were 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
654	C<send>.	692	C<send>.
655		693
656	=item $cv->croak ($error)	694	=item $cv->croak ($error)
657		695
658	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
659	C<Carp::croak> with the given error message/object/scalar.	697	C<Carp::croak> with the given error message/object/scalar.
660		698
661	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
662	user/consumer. Doing it this way instead of calling C<croak> directly	700	user/consumer. Doing it this way instead of calling C<croak> directly
663	delays the error detetcion, but has the overwhelmign advantage that it	701	delays the error detection, but has the overwhelming advantage that it
664	diagnoses the error at the place where the result is expected, and not	702	diagnoses the error at the place where the result is expected, and not
665	deep in some event clalback without connection to the actual code causing	703	deep in some event callback with no connection to the actual code causing
666	the problem.	704	the problem.
667		705
668	=item $cv->begin ([group callback])	706	=item $cv->begin ([group callback])
669		707
670	=item $cv->end	708	=item $cv->end
…		…
708	one call to C<begin>, so the condvar waits for all calls to C<end> before	746	one call to C<begin>, so the condvar waits for all calls to C<end> before
709	sending.	747	sending.
710		748
711	The ping example mentioned above is slightly more complicated, as the	749	The ping example mentioned above is slightly more complicated, as the
712	there are results to be passwd back, and the number of tasks that are	750	there are results to be passwd back, and the number of tasks that are
713	begung can potentially be zero:	751	begun can potentially be zero:
714		752
715	my $cv = AnyEvent->condvar;	753	my $cv = AnyEvent->condvar;
716		754
717	my %result;	755	my %result;
718	$cv->begin (sub { shift->send (\%result) });	756	$cv->begin (sub { shift->send (\%result) });
…		…
739	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
740	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
741	doesn't execute once).	779	doesn't execute once).
742		780
743	This is the general pattern when you "fan out" into multiple (but	781	This is the general pattern when you "fan out" into multiple (but
744	potentially none) subrequests: use an outer C<begin>/C<end> pair to set	782	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
745	the callback and ensure C<end> is called at least once, and then, for each	783	the callback and ensure C<end> is called at least once, and then, for each
746	subrequest you start, call C<begin> and for each subrequest you finish,	784	subrequest you start, call C<begin> and for each subrequest you finish,
747	call C<end>.	785	call C<end>.
748		786
749	=back	787	=back
…		…
756	=over 4	794	=over 4
757		795
758	=item $cv->recv	796	=item $cv->recv
759		797
760	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	798	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
761	>> methods have been called on c<$cv>, while servicing other watchers	799	>> methods have been called on C<$cv>, while servicing other watchers
762	normally.	800	normally.
763		801
764	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
765	will return immediately.	803	will return immediately.
766		804
…		…
783	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
784	condition variables with some kind of request results and supporting	822	condition variables with some kind of request results and supporting
785	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,
786	while still supporting blocking waits if the caller so desires).	824	while still supporting blocking waits if the caller so desires).
787		825
788	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
789	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
790	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
791	waits otherwise.	829	waits otherwise.
792		830
793	=item $bool = $cv->ready	831	=item $bool = $cv->ready
…		…
798	=item $cb = $cv->cb ($cb->($cv))	836	=item $cb = $cv->cb ($cb->($cv))
799		837
800	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
801	replaces it before doing so.	839	replaces it before doing so.
802		840
803	The callback will be called when the condition becomes (or already was)	841	The callback will be called when the condition becomes "true", i.e. when
804	"true", i.e. when C<send> or C<croak> are called (or were called), with	842	C<send> or C<croak> are called, with the only argument being the
805	the only argument being the condition variable itself. Calling C<recv>	843	condition variable itself. If the condition is already true, the
		844	callback is called immediately when it is set. Calling C<recv> inside
806	inside the callback or at any later time is guaranteed not to block.	845	the callback or at any later time is guaranteed not to block.
807		846
808	=back	847	=back
809		848
810	=head1 SUPPORTED EVENT LOOPS/BACKENDS	849	=head1 SUPPORTED EVENT LOOPS/BACKENDS
811		850
…		…
819	use. If EV is not installed, then AnyEvent will fall back to its own	858	use. If EV is not installed, then AnyEvent will fall back to its own
820	pure-perl implementation, which is available everywhere as it comes with	859	pure-perl implementation, which is available everywhere as it comes with
821	AnyEvent itself.	860	AnyEvent itself.
822		861
823	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	862	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
824	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	863	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
825		864
826	=item Backends that are transparently being picked up when they are used.	865	=item Backends that are transparently being picked up when they are used.
827		866
828	These will be used when they are currently loaded when the first watcher	867	These will be used if they are already loaded when the first watcher
829	is created, in which case it is assumed that the application is using	868	is created, in which case it is assumed that the application is using
830	them. This means that AnyEvent will automatically pick the right backend	869	them. This means that AnyEvent will automatically pick the right backend
831	when the main program loads an event module before anything starts to	870	when the main program loads an event module before anything starts to
832	create watchers. Nothing special needs to be done by the main program.	871	create watchers. Nothing special needs to be done by the main program.
833		872
…		…
835	AnyEvent::Impl::Glib based on Glib, slow but very stable.	874	AnyEvent::Impl::Glib based on Glib, slow but very stable.
836	AnyEvent::Impl::Tk based on Tk, very broken.	875	AnyEvent::Impl::Tk based on Tk, very broken.
837	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	876	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
838	AnyEvent::Impl::POE based on POE, very slow, some limitations.	877	AnyEvent::Impl::POE based on POE, very slow, some limitations.
839	AnyEvent::Impl::Irssi used when running within irssi.	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).
840		882
841	=item Backends with special needs.	883	=item Backends with special needs.
842		884
843	Qt requires the Qt::Application to be instantiated first, but will	885	Qt requires the Qt::Application to be instantiated first, but will
844	otherwise be picked up automatically. As long as the main program	886	otherwise be picked up automatically. As long as the main program
845	instantiates the application before any AnyEvent watchers are created,	887	instantiates the application before any AnyEvent watchers are created,
846	everything should just work.	888	everything should just work.
847		889
848	AnyEvent::Impl::Qt based on Qt.	890	AnyEvent::Impl::Qt based on Qt.
849		891
850	Support for IO::Async can only be partial, as it is too broken and
851	architecturally limited to even support the AnyEvent API. It also
852	is the only event loop that needs the loop to be set explicitly, so
853	it can only be used by a main program knowing about AnyEvent. See
854	L<AnyEvent::Impl::Async> for the gory details.
855
856	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
857
858	=item Event loops that are indirectly supported via other backends.	892	=item Event loops that are indirectly supported via other backends.
859		893
860	Some event loops can be supported via other modules:	894	Some event loops can be supported via other modules:
861		895
862	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.	896	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
…		…
887	Contains C<undef> until the first watcher is being created, before the	921	Contains C<undef> until the first watcher is being created, before the
888	backend has been autodetected.	922	backend has been autodetected.
889		923
890	Afterwards it contains the event model that is being used, which is the	924	Afterwards it contains the event model that is being used, which is the
891	name of the Perl class implementing the model. This class is usually one	925	name of the Perl class implementing the model. This class is usually one
892	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the	926	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
893	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it	927	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
894	will be C<urxvt::anyevent>).	928	will be C<urxvt::anyevent>).
895		929
896	=item AnyEvent::detect	930	=item AnyEvent::detect
897		931
898	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	932	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
899	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
900	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
901	runtime, and not e.g. while initialising of your module.	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).
902		940
903	If you need to do some initialisation before AnyEvent watchers are	941	If you need to do some initialisation before AnyEvent watchers are
904	created, use C<post_detect>.	942	created, use C<post_detect>.
905		943
906	=item $guard = AnyEvent::post_detect { BLOCK }	944	=item $guard = AnyEvent::post_detect { BLOCK }
907		945
908	Arranges for the code block to be executed as soon as the event model is	946	Arranges for the code block to be executed as soon as the event model is
909	autodetected (or immediately if this has already happened).	947	autodetected (or immediately if that has already happened).
910		948
911	The block will be executed I<after> the actual backend has been detected	949	The block will be executed I<after> the actual backend has been detected
912	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	950	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
913	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	951	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
914	other initialisations - see the sources of L<AnyEvent::Strict> or	952	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
923	that automatically removes the callback again when it is destroyed (or	961	that automatically removes the callback again when it is destroyed (or
924	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for	962	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
925	a case where this is useful.	963	a case where this is useful.
926		964
927	Example: Create a watcher for the IO::AIO module and store it in	965	Example: Create a watcher for the IO::AIO module and store it in
928	C<$WATCHER>. Only do so after the event loop is initialised, though.	966	C<$WATCHER>, but do so only do so after the event loop is initialised.
929		967
930	our WATCHER;	968	our WATCHER;
931		969
932	my $guard = AnyEvent::post_detect {	970	my $guard = AnyEvent::post_detect {
933	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);	971	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
…		…
941	$WATCHER ||= $guard;	979	$WATCHER ||= $guard;
942		980
943	=item @AnyEvent::post_detect	981	=item @AnyEvent::post_detect
944		982
945	If there are any code references in this array (you can C<push> to it	983	If there are any code references in this array (you can C<push> to it
946	before or after loading AnyEvent), then they will called directly after	984	before or after loading AnyEvent), then they will be called directly
947	the event loop has been chosen.	985	after the event loop has been chosen.
948		986
949	You should check C<$AnyEvent::MODEL> before adding to this array, though:	987	You should check C<$AnyEvent::MODEL> before adding to this array, though:
950	if it is defined then the event loop has already been detected, and the	988	if it is defined then the event loop has already been detected, and the
951	array will be ignored.	989	array will be ignored.
952		990
953	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	991	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
954	it,as it takes care of these details.	992	it, as it takes care of these details.
955		993
956	This variable is mainly useful for modules that can do something useful	994	This variable is mainly useful for modules that can do something useful
957	when AnyEvent is used and thus want to know when it is initialised, but do	995	when AnyEvent is used and thus want to know when it is initialised, but do
958	not need to even load it by default. This array provides the means to hook	996	not need to even load it by default. This array provides the means to hook
959	into AnyEvent passively, without loading it.	997	into AnyEvent passively, without loading it.
960		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.
		1069
961	=back	1070	=back
962		1071
963	=head1 WHAT TO DO IN A MODULE	1072	=head1 WHAT TO DO IN A MODULE
964		1073
965	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1074	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
975	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
976	events is to stay interactive.	1085	events is to stay interactive.
977		1086
978	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
979	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
980	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 >>
981	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).
982		1091
983	=head1 WHAT TO DO IN THE MAIN PROGRAM	1092	=head1 WHAT TO DO IN THE MAIN PROGRAM
984		1093
985	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
986	dictate which event model to use.	1095	dictate which event model to use.
987		1096
988	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
989	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
990	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.
991		1102
992	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
993	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
994	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
995	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
996	modules might create watchers when they are loaded, and AnyEvent will	1107	modules might create watchers when they are loaded, and AnyEvent will
997	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
998	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.
999		1110
1000	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
1001	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1112	C<AnyEvent::Loop> module, which gives you similar behaviour
1002	everywhere, but letting AnyEvent chose the model is generally better.	1113	everywhere, but letting AnyEvent chose the model is generally better.
1003		1114
1004	=head2 MAINLOOP EMULATION	1115	=head2 MAINLOOP EMULATION
1005		1116
1006	Sometimes (often for short test scripts, or even standalone programs who	1117	Sometimes (often for short test scripts, or even standalone programs who
…		…
1019		1130
1020		1131
1021	=head1 OTHER MODULES	1132	=head1 OTHER MODULES
1022		1133
1023	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
1024	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1135	AnyEvent as a client and can therefore be mixed easily with other
1025	modules and other event loops in the same program. Some of the modules	1136	AnyEvent modules and other event loops in the same program. Some of the
1026	come with AnyEvent, most are 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 :)
1027		1141
1028	=over 4	1142	=over 4
1029		1143
1030	=item L<AnyEvent::Util>	1144	=item L<AnyEvent::Util>
1031		1145
1032	Contains various utility functions that replace often-used but blocking	1146	Contains various utility functions that replace often-used blocking
1033	functions such as C<inet_aton> by event-/callback-based versions.	1147	functions such as C<inet_aton> with event/callback-based versions.
1034		1148
1035	=item L<AnyEvent::Socket>	1149	=item L<AnyEvent::Socket>
1036		1150
1037	Provides various utility functions for (internet protocol) sockets,	1151	Provides various utility functions for (internet protocol) sockets,
1038	addresses and name resolution. Also functions to create non-blocking tcp	1152	addresses and name resolution. Also functions to create non-blocking tcp
…		…
1040		1154
1041	=item L<AnyEvent::Handle>	1155	=item L<AnyEvent::Handle>
1042		1156
1043	Provide read and write buffers, manages watchers for reads and writes,	1157	Provide read and write buffers, manages watchers for reads and writes,
1044	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
1045	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1159	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1046		1160
1047	=item L<AnyEvent::DNS>	1161	=item L<AnyEvent::DNS>
1048		1162
1049	Provides rich asynchronous DNS resolver capabilities.	1163	Provides rich asynchronous DNS resolver capabilities.
1050		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
1051	=item L<AnyEvent::HTTP>	1171	=item L<AnyEvent::AIO>
1052		1172
1053	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
1054	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.
1055		1195
1056	=item L<AnyEvent::HTTPD>	1196	=item L<AnyEvent::HTTPD>
1057		1197
1058	Provides a simple web application server framework.	1198	A simple embedded webserver.
1059		1199
1060	=item L<AnyEvent::FastPing>	1200	=item L<AnyEvent::FastPing>
1061		1201
1062	The fastest ping in the west.	1202	The fastest ping in the west.
1063		1203
1064	=item L<AnyEvent::DBI>
1065
1066	Executes L<DBI> requests asynchronously in a proxy process.
1067
1068	=item L<AnyEvent::AIO>
1069
1070	Truly asynchronous I/O, should be in the toolbox of every event
1071	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1072	together.
1073
1074	=item L<AnyEvent::BDB>
1075
1076	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1077	L<BDB> and AnyEvent together.
1078
1079	=item L<AnyEvent::GPSD>
1080
1081	A non-blocking interface to gpsd, a daemon delivering GPS information.
1082
1083	=item L<AnyEvent::IRC>
1084
1085	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1086
1087	=item L<AnyEvent::XMPP>
1088
1089	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1090	Net::XMPP2>.
1091
1092	=item L<AnyEvent::IGS>
1093
1094	A non-blocking interface to the Internet Go Server protocol (used by
1095	L<App::IGS>).
1096
1097	=item L<Net::FCP>
1098
1099	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1100	of AnyEvent.
1101
1102	=item L<Event::ExecFlow>
1103
1104	High level API for event-based execution flow control.
1105
1106	=item L<Coro>	1204	=item L<Coro>
1107		1205
1108	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:
		1208
		1209	async {
		1210	Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
		1211	print "5 seconds later!\n";
		1212
		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	};
1109		1219
1110	=back	1220	=back
1111		1221
1112	=cut	1222	=cut
1113		1223
1114	package AnyEvent;	1224	package AnyEvent;
1115		1225
1116	# basically a tuned-down version of common::sense	1226	# basically a tuned-down version of common::sense
1117	sub common_sense {	1227	sub common_sense {
1118	# from common:.sense 1.0	1228	# from common:.sense 3.4
1119	${^WARNING_BITS} = "\xfc\x3f\xf3\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x03";	1229	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1120	# use strict vars subs	1230	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1121	$^H |= 0x00000600;	1231	$^H |= 0x00000600;
1122	}	1232	}
1123		1233
1124	BEGIN { AnyEvent::common_sense }	1234	BEGIN { AnyEvent::common_sense }
1125		1235
1126	use Carp ();	1236	use Carp ();
1127		1237
1128	our $VERSION = '5.21';	1238	our $VERSION = '6.14';
1129	our $MODEL;	1239	our $MODEL;
1130
1131	our $AUTOLOAD;
1132	our @ISA;	1240	our @ISA;
1133
1134	our @REGISTRY;	1241	our @REGISTRY;
1135
1136	our $VERBOSE;	1242	our $VERBOSE;
		1243	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
		1244	our $MAX_SIGNAL_LATENCY = $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} || 10; # executes after the BEGIN block below (tainting!)
1137		1245
1138	BEGIN {	1246	BEGIN {
1139	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1247	require "AnyEvent/constants.pl";
		1248
1140	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1249	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1141		1250
1142	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1251	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1143	if ${^TAINT};	1252	if ${^TAINT};
1144		1253
1145	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1254	$ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
		1255	for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
1146		1256
1147	}	1257	@ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
		1258	if ${^TAINT};
1148		1259
1149	our $MAX_SIGNAL_LATENCY = 10;	1260	# $ENV{PERL_ANYEVENT_xxx} now valid
1150		1261
1151	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1262	$VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 4;
1152		1263
1153	{
1154	my $idx;	1264	my $idx;
1155	$PROTOCOL{$_} = ++$idx	1265	$PROTOCOL{$_} = ++$idx
1156	for reverse split /\s*,\s*/,	1266	for reverse split /\s*,\s*/,
1157	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1267	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1158	}	1268	}
1159		1269
		1270	our @post_detect;
		1271
		1272	sub post_detect(&) {
		1273	my ($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
1160	my @models = (	1347	our @models = (
1161	[EV:: => AnyEvent::Impl::EV:: , 1],	1348	[EV:: => AnyEvent::Impl::EV::],
1162	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],	1349	[AnyEvent::Loop:: => AnyEvent::Impl::Perl::],
1163	# everything below here will not (normally) be autoprobed	1350	# everything below here will not (normally) be autoprobed
1164	# as the pureperl backend should work everywhere	1351	# as the pure perl backend should work everywhere
1165	# 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
1166	[Event:: => AnyEvent::Impl::Event::, 1],	1354	[Event:: => AnyEvent::Impl::Event::], # slow, stable
1167	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers	1355	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
		1356	# everything below here should not be autoloaded
1168	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1357	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1169	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1170	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1358	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1171	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1359	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1172	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1360	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1173	[Wx:: => AnyEvent::Impl::POE::],	1361	[Wx:: => AnyEvent::Impl::POE::],
1174	[Prima:: => AnyEvent::Impl::POE::],	1362	[Prima:: => AnyEvent::Impl::POE::],
1175	# IO::Async is just too broken - we would need workarounds for its	1363	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1176	# byzantine signal and broken child handling, among others.	1364	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1177	# IO::Async is rather hard to detect, as it doesn't have any	1365	[FLTK:: => AnyEvent::Impl::FLTK::],
1178	# obvious default class.
1179	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1180	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1181	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1182	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1183	);	1366	);
1184		1367
1185	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, $reset_ae] : undef;
		1385
		1386	_isa_set;
		1387	}
		1388
		1389	# all autoloaded methods reserve the complete glob, not just the method slot.
		1390	# due to bugs in perls method cache implementation.
1186	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1391	our @methods = qw(io timer time now now_update signal child idle condvar);
1187		1392
1188	our @post_detect;
1189
1190	sub post_detect(&) {	1393	sub detect() {
1191	my ($cb) = @_;	1394	return $MODEL if $MODEL; # some programs keep references to detect
1192		1395
1193	if ($MODEL) {	1396	# IO::Async::Loop::AnyEvent is extremely evil, refuse to work with it
1194	$cb->();	1397	# the author knows about the problems and what it does to AnyEvent as a whole
		1398	# (and the ability of others to use AnyEvent), but simply wants to abuse AnyEvent
		1399	# anyway.
		1400	AnyEvent::log fatal => "AnyEvent: IO::Async::Loop::AnyEvent detected - that module is broken by\n"
		1401	. "design, abuses internals and breaks AnyEvent - will not continue."
		1402	if exists $INC{"IO/Async/Loop/AnyEvent.pm"};
1195		1403
1196	undef	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;
1197	} else {	1423	} else {
1198	push @post_detect, $cb;	1424	AnyEvent::log 4 => "unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1199		1425	}
1200	defined wantarray
1201	? bless \$cb, "AnyEvent::Util::postdetect"
1202	: ()
1203	}	1426	}
1204	}
1205		1427
1206	sub AnyEvent::Util::postdetect::DESTROY {	1428	# check for already loaded models
1207	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1208	}
1209
1210	sub detect() {
1211	unless ($MODEL) {	1429	unless ($MODEL) {
1212	local $SIG{__DIE__};	1430	for (@REGISTRY, @models) {
1213		1431	my ($package, $model) = @$_;
1214	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1432	if (${"$package\::VERSION"} > 0) {
1215	my $model = "AnyEvent::Impl::$1";
1216	if (eval "require $model") {	1433	if (eval "require $model") {
		1434	AnyEvent::log 7 => "autodetected model '$model', using it.";
1217	$MODEL = $model;	1435	$MODEL = $model;
1218	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1436	last;
1219	} else {	1437	} else {
1220	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1438	AnyEvent::log 8 => "detected event loop $package, but cannot load '$model', skipping: $@";
		1439	}
1221	}	1440	}
1222	}	1441	}
1223		1442
1224	# check for already loaded models
1225	unless ($MODEL) {	1443	unless ($MODEL) {
		1444	# try to autoload a model
1226	for (@REGISTRY, @models) {	1445	for (@REGISTRY, @models) {
1227	my ($package, $model) = @$_;	1446	my ($package, $model) = @$_;
		1447	if (
		1448	eval "require $package"
1228	if (${"$package\::VERSION"} > 0) {	1449	and ${"$package\::VERSION"} > 0
1229	if (eval "require $model") {	1450	and eval "require $model"
		1451	) {
		1452	AnyEvent::log 7 => "autoloaded model '$model', using it.";
1230	$MODEL = $model;	1453	$MODEL = $model;
1231	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1232	last;	1454	last;
1233	}
1234	}	1455	}
1235	}	1456	}
1236		1457
1237	unless ($MODEL) {
1238	# try to autoload a model
1239	for (@REGISTRY, @models) {
1240	my ($package, $model, $autoload) = @$_;
1241	if (
1242	$autoload
1243	and eval "require $package"
1244	and ${"$package\::VERSION"} > 0
1245	and eval "require $model"
1246	) {
1247	$MODEL = $model;
1248	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1249	last;
1250	}
1251	}
1252
1253	$MODEL	1458	$MODEL
1254	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1459	or AnyEvent::log fatal => "AnyEvent: backend autodetection failed - did you properly install AnyEvent?";
1255	}
1256	}	1460	}
1257
1258	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1259
1260	unshift @ISA, $MODEL;
1261
1262	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1263
1264	(shift @post_detect)->() while @post_detect;
1265	}	1461	}
1266		1462
		1463	# free memory only needed for probing
		1464	undef @models;
		1465	undef @REGISTRY;
		1466
		1467	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1468
		1469	# now nuke some methods that are overridden by the backend.
		1470	# SUPER usage is not allowed in these.
		1471	for (qw(time signal child idle)) {
		1472	undef &{"AnyEvent::Base::$_"}
		1473	if defined &{"$MODEL\::$_"};
		1474	}
		1475
		1476	_isa_set;
		1477
		1478	# we're officially open!
		1479
		1480	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1481	require AnyEvent::Strict;
		1482	}
		1483
		1484	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1485	require AnyEvent::Debug;
		1486	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1487	}
		1488
		1489	if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1490	require AnyEvent::Socket;
		1491	require AnyEvent::Debug;
		1492
		1493	my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
		1494	$shell =~ s/\$\$/$$/g;
		1495
		1496	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1497	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1498	}
		1499
		1500	# now the anyevent environment is set up as the user told us to, so
		1501	# call the actual user code - post detects
		1502
		1503	(shift @post_detect)->() while @post_detect;
		1504	undef @post_detect;
		1505
		1506	*post_detect = sub(&) {
		1507	shift->();
		1508
		1509	undef
		1510	};
		1511
1267	$MODEL	1512	$MODEL
1268	}	1513	}
1269		1514
1270	sub AUTOLOAD {	1515	for my $name (@methods) {
1271	(my $func = $AUTOLOAD) =~ s/.*://;	1516	*$name = sub {
1272		1517	detect;
1273	$method{$func}	1518	# we use goto because
1274	or Carp::croak "$func: not a valid method for AnyEvent objects";	1519	# a) it makes the thunk more transparent
1275		1520	# b) it allows us to delete the thunk later
1276	detect unless $MODEL;	1521	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1277		1522	};
1278	my $class = shift;
1279	$class->$func (@_);
1280	}	1523	}
1281		1524
1282	# utility function to dup a filehandle. this is used by many backends	1525	# utility function to dup a filehandle. this is used by many backends
1283	# to support binding more than one watcher per filehandle (they usually	1526	# to support binding more than one watcher per filehandle (they usually
1284	# allow only one watcher per fd, so we dup it to get a different one).	1527	# allow only one watcher per fd, so we dup it to get a different one).
…		…
1298		1541
1299	=head1 SIMPLIFIED AE API	1542	=head1 SIMPLIFIED AE API
1300		1543
1301	Starting with version 5.0, AnyEvent officially supports a second, much	1544	Starting with version 5.0, AnyEvent officially supports a second, much
1302	simpler, API that is designed to reduce the calling, typing and memory	1545	simpler, API that is designed to reduce the calling, typing and memory
1303	overhead.	1546	overhead by using function call syntax and a fixed number of parameters.
1304		1547
1305	See the L<AE> manpage for details.	1548	See the L<AE> manpage for details.
1306		1549
1307	=cut	1550	=cut
1308		1551
1309	package AE;	1552	package AE;
1310		1553
1311	our $VERSION = $AnyEvent::VERSION;	1554	our $VERSION = $AnyEvent::VERSION;
1312		1555
		1556	sub _reset() {
		1557	eval q{
		1558	# fall back to the main API by default - backends and AnyEvent::Base
		1559	# implementations can overwrite these.
		1560
1313	sub io($$$) {	1561	sub io($$$) {
1314	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])	1562	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1315	}	1563	}
1316		1564
1317	sub timer($$$) {	1565	sub timer($$$) {
1318	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])	1566	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1319	}	1567	}
1320		1568
1321	sub signal($$) {	1569	sub signal($$) {
1322	AnyEvent->signal (signal => $_[0], cb => $_[1])	1570	AnyEvent->signal (signal => $_[0], cb => $_[1])
1323	}	1571	}
1324		1572
1325	sub child($$) {	1573	sub child($$) {
1326	AnyEvent->child (pid => $_[0], cb => $_[1])	1574	AnyEvent->child (pid => $_[0], cb => $_[1])
1327	}	1575	}
1328		1576
1329	sub idle($) {	1577	sub idle($) {
1330	AnyEvent->idle (cb => $_[0])	1578	AnyEvent->idle (cb => $_[0]);
1331	}	1579	}
1332		1580
1333	sub cv(;&) {	1581	sub cv(;&) {
1334	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())	1582	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1335	}	1583	}
1336		1584
1337	sub now() {	1585	sub now() {
1338	AnyEvent->now	1586	AnyEvent->now
1339	}	1587	}
1340		1588
1341	sub now_update() {	1589	sub now_update() {
1342	AnyEvent->now_update	1590	AnyEvent->now_update
1343	}	1591	}
1344		1592
1345	sub time() {	1593	sub time() {
1346	AnyEvent->time	1594	AnyEvent->time
		1595	}
		1596
		1597	*postpone = \&AnyEvent::postpone;
		1598	*log = \&AnyEvent::log;
		1599	};
		1600	die if $@;
1347	}	1601	}
		1602
		1603	BEGIN { _reset }
1348		1604
1349	package AnyEvent::Base;	1605	package AnyEvent::Base;
1350		1606
1351	# default implementations for many methods	1607	# default implementations for many methods
1352		1608
1353	sub _time() {	1609	sub time {
		1610	eval q{ # poor man's autoloading {}
1354	# probe for availability of Time::HiRes	1611	# probe for availability of Time::HiRes
1355	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1612	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1356	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1613	*time = sub { Time::HiRes::time () };
1357	*_time = \&Time::HiRes::time;	1614	*AE::time = \& Time::HiRes::time ;
		1615	*now = \&time;
		1616	AnyEvent::log 8 => "AnyEvent: using Time::HiRes for sub-second timing accuracy.";
1358	# if (eval "use POSIX (); (POSIX::times())...	1617	# if (eval "use POSIX (); (POSIX::times())...
1359	} else {	1618	} else {
		1619	*time = sub { CORE::time };
		1620	*AE::time = sub (){ CORE::time };
		1621	*now = \&time;
1360	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1622	AnyEvent::log 3 => "using built-in time(), WARNING, no sub-second resolution!";
1361	*_time = sub { time }; # epic fail	1623	}
1362	}	1624	};
		1625	die if $@;
1363		1626
1364	&_time	1627	&time
1365	}	1628	}
1366		1629
1367	sub time { _time }	1630	*now = \&time;
1368	sub now { _time }
1369	sub now_update { }	1631	sub now_update { }
1370		1632
		1633	sub _poll {
		1634	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1635	}
		1636
1371	# default implementation for ->condvar	1637	# default implementation for ->condvar
		1638	# in fact, the default should not be overwritten
1372		1639
1373	sub condvar {	1640	sub condvar {
		1641	eval q{ # poor man's autoloading {}
		1642	*condvar = sub {
1374	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1643	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1644	};
		1645
		1646	*AE::cv = sub (;&) {
		1647	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1648	};
		1649	};
		1650	die if $@;
		1651
		1652	&condvar
1375	}	1653	}
1376		1654
1377	# default implementation for ->signal	1655	# default implementation for ->signal
1378		1656
1379	our $HAVE_ASYNC_INTERRUPT;	1657	our $HAVE_ASYNC_INTERRUPT;
…		…
1388		1666
1389	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1667	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1390	our (%SIG_ASY, %SIG_ASY_W);	1668	our (%SIG_ASY, %SIG_ASY_W);
1391	our ($SIG_COUNT, $SIG_TW);	1669	our ($SIG_COUNT, $SIG_TW);
1392		1670
1393	sub _signal_exec {
1394	$HAVE_ASYNC_INTERRUPT
1395	? $SIGPIPE_R->drain
1396	: sysread $SIGPIPE_R, (my $dummy), 9;
1397
1398	while (%SIG_EV) {
1399	for (keys %SIG_EV) {
1400	delete $SIG_EV{$_};
1401	$_->() for values %{ $SIG_CB{$_} || {} };
1402	}
1403	}
1404	}
1405
1406	# install a dummy wakeup watcher to reduce signal catching latency	1671	# install a dummy wakeup watcher to reduce signal catching latency
		1672	# used by Impls
1407	sub _sig_add() {	1673	sub _sig_add() {
1408	unless ($SIG_COUNT++) {	1674	unless ($SIG_COUNT++) {
1409	# try to align timer on a full-second boundary, if possible	1675	# try to align timer on a full-second boundary, if possible
1410	my $NOW = AE::now;	1676	my $NOW = AE::now;
1411		1677
…		…
1421	undef $SIG_TW	1687	undef $SIG_TW
1422	unless --$SIG_COUNT;	1688	unless --$SIG_COUNT;
1423	}	1689	}
1424		1690
1425	our $_sig_name_init; $_sig_name_init = sub {	1691	our $_sig_name_init; $_sig_name_init = sub {
1426	eval q{ # poor man's autoloading	1692	eval q{ # poor man's autoloading {}
1427	undef $_sig_name_init;	1693	undef $_sig_name_init;
1428		1694
1429	if (_have_async_interrupt) {	1695	if (_have_async_interrupt) {
1430	*sig2num = \&Async::Interrupt::sig2num;	1696	*sig2num = \&Async::Interrupt::sig2num;
1431	*sig2name = \&Async::Interrupt::sig2name;	1697	*sig2name = \&Async::Interrupt::sig2name;
…		…
1455		1721
1456	sub signal {	1722	sub signal {
1457	eval q{ # poor man's autoloading {}	1723	eval q{ # poor man's autoloading {}
1458	# probe for availability of Async::Interrupt	1724	# probe for availability of Async::Interrupt
1459	if (_have_async_interrupt) {	1725	if (_have_async_interrupt) {
1460	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;	1726	AnyEvent::log 8 => "using Async::Interrupt for race-free signal handling.";
1461		1727
1462	$SIGPIPE_R = new Async::Interrupt::EventPipe;	1728	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1463	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;	1729	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1464		1730
1465	} else {	1731	} else {
1466	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;	1732	AnyEvent::log 8 => "using emulated perl signal handling with latency timer.";
1467
1468	require Fcntl;
1469		1733
1470	if (AnyEvent::WIN32) {	1734	if (AnyEvent::WIN32) {
1471	require AnyEvent::Util;	1735	require AnyEvent::Util;
1472		1736
1473	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();	1737	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1474	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;	1738	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1475	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case	1739	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1476	} else {	1740	} else {
1477	pipe $SIGPIPE_R, $SIGPIPE_W;	1741	pipe $SIGPIPE_R, $SIGPIPE_W;
1478	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1742	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1479	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1743	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1480		1744
1481	# not strictly required, as $^F is normally 2, but let's make sure...	1745	# not strictly required, as $^F is normally 2, but let's make sure...
1482	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1746	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1483	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1747	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1484	}	1748	}
1485		1749
1486	$SIGPIPE_R	1750	$SIGPIPE_R
1487	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1751	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1488		1752
1489	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;	1753	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1490	}	1754	}
1491		1755
1492	*signal = sub {	1756	*signal = $HAVE_ASYNC_INTERRUPT
		1757	? sub {
1493	my (undef, %arg) = @_;	1758	my (undef, %arg) = @_;
1494		1759
1495	my $signal = uc $arg{signal}
1496	or Carp::croak "required option 'signal' is missing";
1497
1498	if ($HAVE_ASYNC_INTERRUPT) {
1499	# async::interrupt	1760	# async::interrupt
1500
1501	$signal = sig2num $signal;	1761	my $signal = sig2num $arg{signal};
1502	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1762	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1503		1763
1504	$SIG_ASY{$signal} ||= new Async::Interrupt	1764	$SIG_ASY{$signal} ||= new Async::Interrupt
1505	cb => sub { undef $SIG_EV{$signal} },	1765	cb => sub { undef $SIG_EV{$signal} },
1506	signal => $signal,	1766	signal => $signal,
1507	pipe => [$SIGPIPE_R->filenos],	1767	pipe => [$SIGPIPE_R->filenos],
1508	pipe_autodrain => 0,	1768	pipe_autodrain => 0,
1509	;	1769	;
1510		1770
1511	} else {	1771	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1772	}
		1773	: sub {
		1774	my (undef, %arg) = @_;
		1775
1512	# pure perl	1776	# pure perl
1513
1514	# AE::Util has been loaded in signal
1515	$signal = sig2name $signal;	1777	my $signal = sig2name $arg{signal};
1516	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1778	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1517		1779
1518	$SIG{$signal} ||= sub {	1780	$SIG{$signal} ||= sub {
1519	local $!;	1781	local $!;
1520	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1782	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1521	undef $SIG_EV{$signal};	1783	undef $SIG_EV{$signal};
1522	};	1784	};
1523		1785
1524	# can't do signal processing without introducing races in pure perl,	1786	# can't do signal processing without introducing races in pure perl,
1525	# so limit the signal latency.	1787	# so limit the signal latency.
1526	_sig_add;	1788	_sig_add;
1527	}
1528		1789
1529	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1790	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1791	}
1530	};	1792	;
1531		1793
1532	*AnyEvent::Base::signal::DESTROY = sub {	1794	*AnyEvent::Base::signal::DESTROY = sub {
1533	my ($signal, $cb) = @{$_[0]};	1795	my ($signal, $cb) = @{$_[0]};
1534		1796
1535	_sig_del;	1797	_sig_del;
…		…
1542	# print weird messages, or just unconditionally exit	1804	# print weird messages, or just unconditionally exit
1543	# instead of getting the default action.	1805	# instead of getting the default action.
1544	undef $SIG{$signal}	1806	undef $SIG{$signal}
1545	unless keys %{ $SIG_CB{$signal} };	1807	unless keys %{ $SIG_CB{$signal} };
1546	};	1808	};
		1809
		1810	*_signal_exec = sub {
		1811	$HAVE_ASYNC_INTERRUPT
		1812	? $SIGPIPE_R->drain
		1813	: sysread $SIGPIPE_R, (my $dummy), 9;
		1814
		1815	while (%SIG_EV) {
		1816	for (keys %SIG_EV) {
		1817	delete $SIG_EV{$_};
		1818	&$_ for values %{ $SIG_CB{$_} || {} };
		1819	}
		1820	}
		1821	};
1547	};	1822	};
1548	die if $@;	1823	die if $@;
		1824
1549	&signal	1825	&signal
1550	}	1826	}
1551		1827
1552	# default implementation for ->child	1828	# default implementation for ->child
1553		1829
1554	our %PID_CB;	1830	our %PID_CB;
1555	our $CHLD_W;	1831	our $CHLD_W;
1556	our $CHLD_DELAY_W;	1832	our $CHLD_DELAY_W;
1557	our $WNOHANG;
1558		1833
		1834	# used by many Impl's
1559	sub _emit_childstatus($$) {	1835	sub _emit_childstatus($$) {
1560	my (undef, $rpid, $rstatus) = @_;	1836	my (undef, $rpid, $rstatus) = @_;
1561		1837
1562	$_->($rpid, $rstatus)	1838	$_->($rpid, $rstatus)
1563	for values %{ $PID_CB{$rpid} || {} },	1839	for values %{ $PID_CB{$rpid} || {} },
1564	values %{ $PID_CB{0} || {} };	1840	values %{ $PID_CB{0} || {} };
1565	}	1841	}
1566		1842
1567	sub _sigchld {
1568	my $pid;
1569
1570	AnyEvent->_emit_childstatus ($pid, $?)
1571	while ($pid = waitpid -1, $WNOHANG) > 0;
1572	}
1573
1574	sub child {	1843	sub child {
		1844	eval q{ # poor man's autoloading {}
		1845	*_sigchld = sub {
		1846	my $pid;
		1847
		1848	AnyEvent->_emit_childstatus ($pid, $?)
		1849	while ($pid = waitpid -1, WNOHANG) > 0;
		1850	};
		1851
		1852	*child = sub {
1575	my (undef, %arg) = @_;	1853	my (undef, %arg) = @_;
1576		1854
1577	defined (my $pid = $arg{pid} + 0)	1855	my $pid = $arg{pid};
1578	or Carp::croak "required option 'pid' is missing";	1856	my $cb = $arg{cb};
1579		1857
1580	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1858	$PID_CB{$pid}{$cb+0} = $cb;
1581		1859
1582	# WNOHANG is almost cetrainly 1 everywhere
1583	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1584	? 1
1585	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1586
1587	unless ($CHLD_W) {	1860	unless ($CHLD_W) {
1588	$CHLD_W = AE::signal CHLD => \&_sigchld;	1861	$CHLD_W = AE::signal CHLD => \&_sigchld;
1589	# child could be a zombie already, so make at least one round	1862	# child could be a zombie already, so make at least one round
1590	&_sigchld;	1863	&_sigchld;
1591	}	1864	}
1592		1865
1593	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1866	bless [$pid, $cb+0], "AnyEvent::Base::child"
1594	}	1867	};
1595		1868
1596	sub AnyEvent::Base::child::DESTROY {	1869	*AnyEvent::Base::child::DESTROY = sub {
1597	my ($pid, $cb) = @{$_[0]};	1870	my ($pid, $icb) = @{$_[0]};
1598		1871
1599	delete $PID_CB{$pid}{$cb};	1872	delete $PID_CB{$pid}{$icb};
1600	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1873	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1601		1874
1602	undef $CHLD_W unless keys %PID_CB;	1875	undef $CHLD_W unless keys %PID_CB;
		1876	};
		1877	};
		1878	die if $@;
		1879
		1880	&child
1603	}	1881	}
1604		1882
1605	# idle emulation is done by simply using a timer, regardless	1883	# idle emulation is done by simply using a timer, regardless
1606	# of whether the process is idle or not, and not letting	1884	# of whether the process is idle or not, and not letting
1607	# the callback use more than 50% of the time.	1885	# the callback use more than 50% of the time.
1608	sub idle {	1886	sub idle {
		1887	eval q{ # poor man's autoloading {}
		1888	*idle = sub {
1609	my (undef, %arg) = @_;	1889	my (undef, %arg) = @_;
1610		1890
1611	my ($cb, $w, $rcb) = $arg{cb};	1891	my ($cb, $w, $rcb) = $arg{cb};
1612		1892
1613	$rcb = sub {	1893	$rcb = sub {
1614	if ($cb) {	1894	if ($cb) {
1615	$w = _time;	1895	$w = AE::time;
1616	&$cb;	1896	&$cb;
1617	$w = _time - $w;	1897	$w = AE::time - $w;
1618		1898
1619	# never use more then 50% of the time for the idle watcher,	1899	# never use more then 50% of the time for the idle watcher,
1620	# within some limits	1900	# within some limits
1621	$w = 0.0001 if $w < 0.0001;	1901	$w = 0.0001 if $w < 0.0001;
1622	$w = 5 if $w > 5;	1902	$w = 5 if $w > 5;
1623		1903
1624	$w = AE::timer $w, 0, $rcb;	1904	$w = AE::timer $w, 0, $rcb;
1625	} else {	1905	} else {
1626	# clean up...	1906	# clean up...
1627	undef $w;	1907	undef $w;
1628	undef $rcb;	1908	undef $rcb;
		1909	}
		1910	};
		1911
		1912	$w = AE::timer 0.05, 0, $rcb;
		1913
		1914	bless \\$cb, "AnyEvent::Base::idle"
1629	}	1915	};
		1916
		1917	*AnyEvent::Base::idle::DESTROY = sub {
		1918	undef $${$_[0]};
		1919	};
1630	};	1920	};
		1921	die if $@;
1631		1922
1632	$w = AE::timer 0.05, 0, $rcb;	1923	&idle
1633
1634	bless \\$cb, "AnyEvent::Base::idle"
1635	}
1636
1637	sub AnyEvent::Base::idle::DESTROY {
1638	undef $${$_[0]};
1639	}	1924	}
1640		1925
1641	package AnyEvent::CondVar;	1926	package AnyEvent::CondVar;
1642		1927
1643	our @ISA = AnyEvent::CondVar::Base::;	1928	our @ISA = AnyEvent::CondVar::Base::;
		1929
		1930	# only to be used for subclassing
		1931	sub new {
		1932	my $class = shift;
		1933	bless AnyEvent->condvar (@_), $class
		1934	}
1644		1935
1645	package AnyEvent::CondVar::Base;	1936	package AnyEvent::CondVar::Base;
1646		1937
1647	#use overload	1938	#use overload
1648	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1939	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
…		…
1658		1949
1659	sub _send {	1950	sub _send {
1660	# nop	1951	# nop
1661	}	1952	}
1662		1953
		1954	sub _wait {
		1955	AnyEvent->_poll until $_[0]{_ae_sent};
		1956	}
		1957
1663	sub send {	1958	sub send {
1664	my $cv = shift;	1959	my $cv = shift;
1665	$cv->{_ae_sent} = [@_];	1960	$cv->{_ae_sent} = [@_];
1666	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};	1961	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1667	$cv->_send;	1962	$cv->_send;
…		…
1674		1969
1675	sub ready {	1970	sub ready {
1676	$_[0]{_ae_sent}	1971	$_[0]{_ae_sent}
1677	}	1972	}
1678		1973
1679	sub _wait {
1680	$WAITING
1681	and !$_[0]{_ae_sent}
1682	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1683
1684	local $WAITING = 1;
1685	AnyEvent->one_event while !$_[0]{_ae_sent};
1686	}
1687
1688	sub recv {	1974	sub recv {
		1975	unless ($_[0]{_ae_sent}) {
		1976	$WAITING
		1977	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1978
		1979	local $WAITING = 1;
1689	$_[0]->_wait;	1980	$_[0]->_wait;
		1981	}
1690		1982
1691	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1983	$_[0]{_ae_croak}
1692	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1984	and Carp::croak $_[0]{_ae_croak};
		1985
		1986	wantarray
		1987	? @{ $_[0]{_ae_sent} }
		1988	: $_[0]{_ae_sent}[0]
1693	}	1989	}
1694		1990
1695	sub cb {	1991	sub cb {
1696	my $cv = shift;	1992	my $cv = shift;
1697		1993
…		…
1713	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	2009	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1714	}	2010	}
1715		2011
1716	# undocumented/compatibility with pre-3.4	2012	# undocumented/compatibility with pre-3.4
1717	*broadcast = \&send;	2013	*broadcast = \&send;
1718	*wait = \&_wait;	2014	*wait = \&recv;
1719		2015
1720	=head1 ERROR AND EXCEPTION HANDLING	2016	=head1 ERROR AND EXCEPTION HANDLING
1721		2017
1722	In general, AnyEvent does not do any error handling - it relies on the	2018	In general, AnyEvent does not do any error handling - it relies on the
1723	caller to do that if required. The L<AnyEvent::Strict> module (see also	2019	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1735	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and	2031	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1736	so on.	2032	so on.
1737		2033
1738	=head1 ENVIRONMENT VARIABLES	2034	=head1 ENVIRONMENT VARIABLES
1739		2035
1740	The following environment variables are used by this module or its	2036	AnyEvent supports a number of environment variables that tune the
1741	submodules.	2037	runtime behaviour. They are usually evaluated when AnyEvent is
		2038	loaded, initialised, or a submodule that uses them is loaded. Many of
		2039	them also cause AnyEvent to load additional modules - for example,
		2040	C<PERL_ANYEVENT_DEBUG_WRAP> causes the L<AnyEvent::Debug> module to be
		2041	loaded.
1742		2042
1743	Note that AnyEvent will remove I<all> environment variables starting with	2043	All the environment variables documented here start with
1744	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is	2044	C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
1745	enabled.	2045	namespace. Other modules are encouraged (but by no means required) to use
		2046	C<PERL_ANYEVENT_SUBMODULE> if they have registered the AnyEvent::Submodule
		2047	namespace on CPAN, for any submodule. For example, L<AnyEvent::HTTP> could
		2048	be expected to use C<PERL_ANYEVENT_HTTP_PROXY> (it should not access env
		2049	variables starting with C<AE_>, see below).
		2050
		2051	All variables can also be set via the C<AE_> prefix, that is, instead
		2052	of setting C<PERL_ANYEVENT_VERBOSE> you can also set C<AE_VERBOSE>. In
		2053	case there is a clash btween anyevent and another program that uses
		2054	C<AE_something> you can set the corresponding C<PERL_ANYEVENT_something>
		2055	variable to the empty string, as those variables take precedence.
		2056
		2057	When AnyEvent is first loaded, it copies all C<AE_xxx> env variables
		2058	to their C<PERL_ANYEVENT_xxx> counterpart unless that variable already
		2059	exists. If taint mode is on, then AnyEvent will remove I<all> environment
		2060	variables starting with C<PERL_ANYEVENT_> from C<%ENV> (or replace them
		2061	with C<undef> or the empty string, if the corresaponding C<AE_> variable
		2062	is set).
		2063
		2064	The exact algorithm is currently:
		2065
		2066	1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
		2067	2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
		2068	3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
		2069
		2070	This ensures that child processes will not see the C<AE_> variables.
		2071
		2072	The following environment variables are currently known to AnyEvent:
1746		2073
1747	=over 4	2074	=over 4
1748		2075
1749	=item C<PERL_ANYEVENT_VERBOSE>	2076	=item C<PERL_ANYEVENT_VERBOSE>
1750		2077
1751	By default, AnyEvent will be completely silent except in fatal	2078	By default, AnyEvent will only log messages with loglevel C<3>
1752	conditions. You can set this environment variable to make AnyEvent more	2079	(C<critical>) or higher (see L<AnyEvent::Log>). You can set this
		2080	environment variable to a numerical loglevel to make AnyEvent more (or
1753	talkative.	2081	less) talkative.
1754		2082
		2083	If you want to do more than just set the global logging level
		2084	you should have a look at C<PERL_ANYEVENT_LOG>, which allows much more
		2085	complex specifications.
		2086
		2087	When set to C<0> (C<off>), then no messages whatsoever will be logged with
		2088	the default logging settings.
		2089
1755	When set to C<1> or higher, causes AnyEvent to warn about unexpected	2090	When set to C<5> or higher (C<warn>), causes AnyEvent to warn about
1756	conditions, such as not being able to load the event model specified by	2091	unexpected conditions, such as not being able to load the event model
1757	C<PERL_ANYEVENT_MODEL>.	2092	specified by C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an
		2093	exception - this is the minimum recommended level.
1758		2094
1759	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	2095	When set to C<7> or higher (info), cause AnyEvent to report which event model it
1760	model it chooses.	2096	chooses.
1761		2097
1762	When set to C<8> or higher, then AnyEvent will report extra information on	2098	When set to C<8> or higher (debug), then AnyEvent will report extra information on
1763	which optional modules it loads and how it implements certain features.	2099	which optional modules it loads and how it implements certain features.
		2100
		2101	=item C<PERL_ANYEVENT_LOG>
		2102
		2103	Accepts rather complex logging specifications. For example, you could log
		2104	all C<debug> messages of some module to stderr, warnings and above to
		2105	stderr, and errors and above to syslog, with:
		2106
		2107	PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
		2108
		2109	For the rather extensive details, see L<AnyEvent::Log>.
		2110
		2111	This variable is evaluated when AnyEvent (or L<AnyEvent::Log>) is loaded,
		2112	so will take effect even before AnyEvent has initialised itself.
		2113
		2114	Note that specifying this environment variable causes the L<AnyEvent::Log>
		2115	module to be loaded, while C<PERL_ANYEVENT_VERBOSE> does not, so only
		2116	using the latter saves a few hundred kB of memory until the first message
		2117	is being logged.
1764		2118
1765	=item C<PERL_ANYEVENT_STRICT>	2119	=item C<PERL_ANYEVENT_STRICT>
1766		2120
1767	AnyEvent does not do much argument checking by default, as thorough	2121	AnyEvent does not do much argument checking by default, as thorough
1768	argument checking is very costly. Setting this variable to a true value	2122	argument checking is very costly. Setting this variable to a true value
…		…
1770	check the arguments passed to most method calls. If it finds any problems,	2124	check the arguments passed to most method calls. If it finds any problems,
1771	it will croak.	2125	it will croak.
1772		2126
1773	In other words, enables "strict" mode.	2127	In other words, enables "strict" mode.
1774		2128
1775	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	2129	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1776	>>, it is definitely recommended to keep it off in production. Keeping	2130	>>, it is definitely recommended to keep it off in production. Keeping
1777	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	2131	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1778	can be very useful, however.	2132	can be very useful, however.
1779		2133
		2134	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		2135
		2136	If this env variable is nonempty, then its contents will be interpreted by
		2137	C<AnyEvent::Socket::parse_hostport> and C<AnyEvent::Debug::shell> (after
		2138	replacing every occurance of C<$$> by the process pid). The shell object
		2139	is saved in C<$AnyEvent::Debug::SHELL>.
		2140
		2141	This happens when the first watcher is created.
		2142
		2143	For example, to bind a debug shell on a unix domain socket in
		2144	F<< /tmp/debug<pid>.sock >>, you could use this:
		2145
		2146	PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
		2147	# connect with e.g.: socat readline /tmp/debug123.sock
		2148
		2149	Or to bind to tcp port 4545 on localhost:
		2150
		2151	PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog
		2152	# connect with e.g.: telnet localhost 4545
		2153
		2154	Note that creating sockets in F</tmp> or on localhost is very unsafe on
		2155	multiuser systems.
		2156
		2157	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		2158
		2159	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		2160	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
		2161
1780	=item C<PERL_ANYEVENT_MODEL>	2162	=item C<PERL_ANYEVENT_MODEL>
1781		2163
1782	This can be used to specify the event model to be used by AnyEvent, before	2164	This can be used to specify the event model to be used by AnyEvent, before
1783	auto detection and -probing kicks in. It must be a string consisting	2165	auto detection and -probing kicks in.
1784	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	2166
		2167	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		2168	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1785	and the resulting module name is loaded and if the load was successful,	2169	resulting module name is loaded and - if the load was successful - used as
1786	used as event model. If it fails to load AnyEvent will proceed with	2170	event model backend. If it fails to load then AnyEvent will proceed with
1787	auto detection and -probing.	2171	auto detection and -probing.
1788		2172
1789	This functionality might change in future versions.	2173	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		2174	nothing gets prepended and the module name is used as-is (hint: C<::> at
		2175	the end of a string designates a module name and quotes it appropriately).
1790		2176
1791	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	2177	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1792	could start your program like this:	2178	could start your program like this:
1793		2179
1794	PERL_ANYEVENT_MODEL=Perl perl ...	2180	PERL_ANYEVENT_MODEL=Perl perl ...
1795		2181
1796	=item C<PERL_ANYEVENT_PROTOCOLS>	2182	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
1812	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>	2198	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1813	- only support IPv4, never try to resolve or contact IPv6	2199	- only support IPv4, never try to resolve or contact IPv6
1814	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or	2200	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1815	IPv6, but prefer IPv6 over IPv4.	2201	IPv6, but prefer IPv6 over IPv4.
1816		2202
		2203	=item C<PERL_ANYEVENT_HOSTS>
		2204
		2205	This variable, if specified, overrides the F</etc/hosts> file used by
		2206	L<AnyEvent::Socket>C<::resolve_sockaddr>, i.e. hosts aliases will be read
		2207	from that file instead.
		2208
1817	=item C<PERL_ANYEVENT_EDNS0>	2209	=item C<PERL_ANYEVENT_EDNS0>
1818		2210
1819	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension	2211	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension for
1820	for DNS. This extension is generally useful to reduce DNS traffic, but	2212	DNS. This extension is generally useful to reduce DNS traffic, especially
1821	some (broken) firewalls drop such DNS packets, which is why it is off by	2213	when DNSSEC is involved, but some (broken) firewalls drop such DNS
1822	default.	2214	packets, which is why it is off by default.
1823		2215
1824	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce	2216	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1825	EDNS0 in its DNS requests.	2217	EDNS0 in its DNS requests.
1826		2218
1827	=item C<PERL_ANYEVENT_MAX_FORKS>	2219	=item C<PERL_ANYEVENT_MAX_FORKS>
…		…
1833		2225
1834	The default value for the C<max_outstanding> parameter for the default DNS	2226	The default value for the C<max_outstanding> parameter for the default DNS
1835	resolver - this is the maximum number of parallel DNS requests that are	2227	resolver - this is the maximum number of parallel DNS requests that are
1836	sent to the DNS server.	2228	sent to the DNS server.
1837		2229
		2230	=item C<PERL_ANYEVENT_MAX_SIGNAL_LATENCY>
		2231
		2232	Perl has inherently racy signal handling (you can basically choose between
		2233	losing signals and memory corruption) - pure perl event loops (including
		2234	C<AnyEvent::Loop>, when C<Async::Interrupt> isn't available) therefore
		2235	have to poll regularly to avoid losing signals.
		2236
		2237	Some event loops are racy, but don't poll regularly, and some event loops
		2238	are written in C but are still racy. For those event loops, AnyEvent
		2239	installs a timer that regularly wakes up the event loop.
		2240
		2241	By default, the interval for this timer is C<10> seconds, but you can
		2242	override this delay with this environment variable (or by setting
		2243	the C<$AnyEvent::MAX_SIGNAL_LATENCY> variable before creating signal
		2244	watchers).
		2245
		2246	Lower values increase CPU (and energy) usage, higher values can introduce
		2247	long delays when reaping children or waiting for signals.
		2248
		2249	The L<AnyEvent::Async> module, if available, will be used to avoid this
		2250	polling (with most event loops).
		2251
1838	=item C<PERL_ANYEVENT_RESOLV_CONF>	2252	=item C<PERL_ANYEVENT_RESOLV_CONF>
1839		2253
1840	The file to use instead of F</etc/resolv.conf> (or OS-specific	2254	The absolute path to a F<resolv.conf>-style file to use instead of
1841	configuration) in the default resolver. When set to the empty string, no	2255	F</etc/resolv.conf> (or the OS-specific configuration) in the default
1842	default config will be used.	2256	resolver, or the empty string to select the default configuration.
1843		2257
1844	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.	2258	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1845		2259
1846	When neither C<ca_file> nor C<ca_path> was specified during	2260	When neither C<ca_file> nor C<ca_path> was specified during
1847	L<AnyEvent::TLS> context creation, and either of these environment	2261	L<AnyEvent::TLS> context creation, and either of these environment
1848	variables exist, they will be used to specify CA certificate locations	2262	variables are nonempty, they will be used to specify CA certificate
1849	instead of a system-dependent default.	2263	locations instead of a system-dependent default.
1850		2264
1851	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>	2265	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1852		2266
1853	When these are set to C<1>, then the respective modules are not	2267	When these are set to C<1>, then the respective modules are not
1854	loaded. Mostly good for testing AnyEvent itself.	2268	loaded. Mostly good for testing AnyEvent itself.
…		…
2002		2416
2003	The actual code goes further and collects all errors (C<die>s, exceptions)	2417	The actual code goes further and collects all errors (C<die>s, exceptions)
2004	that occurred during request processing. The C<result> method detects	2418	that occurred during request processing. The C<result> method detects
2005	whether an exception as thrown (it is stored inside the $txn object)	2419	whether an exception as thrown (it is stored inside the $txn object)
2006	and just throws the exception, which means connection errors and other	2420	and just throws the exception, which means connection errors and other
2007	problems get reported tot he code that tries to use the result, not in a	2421	problems get reported to the code that tries to use the result, not in a
2008	random callback.	2422	random callback.
2009		2423
2010	All of this enables the following usage styles:	2424	All of this enables the following usage styles:
2011		2425
2012	1. Blocking:	2426	1. Blocking:
…		…
2186	(even when used without AnyEvent), but most event loops have acceptable	2600	(even when used without AnyEvent), but most event loops have acceptable
2187	performance with or without AnyEvent.	2601	performance with or without AnyEvent.
2188		2602
2189	=item * The overhead AnyEvent adds is usually much smaller than the overhead of	2603	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
2190	the actual event loop, only with extremely fast event loops such as EV	2604	the actual event loop, only with extremely fast event loops such as EV
2191	adds AnyEvent significant overhead.	2605	does AnyEvent add significant overhead.
2192		2606
2193	=item * You should avoid POE like the plague if you want performance or	2607	=item * You should avoid POE like the plague if you want performance or
2194	reasonable memory usage.	2608	reasonable memory usage.
2195		2609
2196	=back	2610	=back
…		…
2426	unless defined $SIG{PIPE};	2840	unless defined $SIG{PIPE};
2427		2841
2428	=head1 RECOMMENDED/OPTIONAL MODULES	2842	=head1 RECOMMENDED/OPTIONAL MODULES
2429		2843
2430	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2844	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2431	it's built-in modules) are required to use it.	2845	its built-in modules) are required to use it.
2432		2846
2433	That does not mean that AnyEvent won't take advantage of some additional	2847	That does not mean that AnyEvent won't take advantage of some additional
2434	modules if they are installed.	2848	modules if they are installed.
2435		2849
2436	This section epxlains which additional modules will be used, and how they	2850	This section explains which additional modules will be used, and how they
2437	affect AnyEvent's operetion.	2851	affect AnyEvent's operation.
2438		2852
2439	=over 4	2853	=over 4
2440		2854
2441	=item L<Async::Interrupt>	2855	=item L<Async::Interrupt>
2442		2856
…		…
2447	catch the signals) with some delay (default is 10 seconds, look for	2861	catch the signals) with some delay (default is 10 seconds, look for
2448	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2862	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2449		2863
2450	If this module is available, then it will be used to implement signal	2864	If this module is available, then it will be used to implement signal
2451	catching, which means that signals will not be delayed, and the event loop	2865	catching, which means that signals will not be delayed, and the event loop
2452	will not be interrupted regularly, which is more efficient (And good for	2866	will not be interrupted regularly, which is more efficient (and good for
2453	battery life on laptops).	2867	battery life on laptops).
2454		2868
2455	This affects not just the pure-perl event loop, but also other event loops	2869	This affects not just the pure-perl event loop, but also other event loops
2456	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2870	that have no signal handling on their own (e.g. Glib, Tk, Qt).
2457		2871
…		…
2469	automatic timer adjustments even when no monotonic clock is available,	2883	automatic timer adjustments even when no monotonic clock is available,
2470	can take avdantage of advanced kernel interfaces such as C<epoll> and	2884	can take avdantage of advanced kernel interfaces such as C<epoll> and
2471	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2885	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2472	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2886	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2473		2887
		2888	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2889	then this module will do nothing for you.
		2890
2474	=item L<Guard>	2891	=item L<Guard>
2475		2892
2476	The guard module, when used, will be used to implement	2893	The guard module, when used, will be used to implement
2477	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2894	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2478	lot less memory), but otherwise doesn't affect guard operation much. It is	2895	lot less memory), but otherwise doesn't affect guard operation much. It is
2479	purely used for performance.	2896	purely used for performance.
2480		2897
2481	=item L<JSON> and L<JSON::XS>	2898	=item L<JSON> and L<JSON::XS>
2482		2899
2483	One of these modules is required when you want to read or write JSON data	2900	One of these modules is required when you want to read or write JSON data
2484	via L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2901	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2485	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.	2902	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2486
2487	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2488	installed.
2489		2903
2490	=item L<Net::SSLeay>	2904	=item L<Net::SSLeay>
2491		2905
2492	Implementing TLS/SSL in Perl is certainly interesting, but not very	2906	Implementing TLS/SSL in Perl is certainly interesting, but not very
2493	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2907	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2494	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2908	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2495		2909
2496	=item L<Time::HiRes>	2910	=item L<Time::HiRes>
2497		2911
2498	This module is part of perl since release 5.008. It will be used when the	2912	This module is part of perl since release 5.008. It will be used when the
2499	chosen event library does not come with a timing source on it's own. The	2913	chosen event library does not come with a timing source of its own. The
2500	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2914	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2501	try to use a monotonic clock for timing stability.	2915	try to use a monotonic clock for timing stability.
2502		2916
2503	=back	2917	=back
2504		2918
2505		2919
2506	=head1 FORK	2920	=head1 FORK
2507		2921
2508	Most event libraries are not fork-safe. The ones who are usually are	2922	Most event libraries are not fork-safe. The ones who are usually are
2509	because they rely on inefficient but fork-safe C<select> or C<poll>	2923	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2510	calls. Only L<EV> is fully fork-aware.	2924	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2925	are usually badly thought-out hacks that are incompatible with fork in
		2926	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2927	continue event-processing in both parent and child (or both, if you know
		2928	what you are doing).
		2929
		2930	This means that, in general, you cannot fork and do event processing in
		2931	the child if the event library was initialised before the fork (which
		2932	usually happens when the first AnyEvent watcher is created, or the library
		2933	is loaded).
2511		2934
2512	If you have to fork, you must either do so I<before> creating your first	2935	If you have to fork, you must either do so I<before> creating your first
2513	watcher OR you must not use AnyEvent at all in the child OR you must do	2936	watcher OR you must not use AnyEvent at all in the child OR you must do
2514	something completely out of the scope of AnyEvent.	2937	something completely out of the scope of AnyEvent.
		2938
		2939	The problem of doing event processing in the parent I<and> the child
		2940	is much more complicated: even for backends that I<are> fork-aware or
		2941	fork-safe, their behaviour is not usually what you want: fork clones all
		2942	watchers, that means all timers, I/O watchers etc. are active in both
		2943	parent and child, which is almost never what you want. USing C<exec>
		2944	to start worker children from some kind of manage rprocess is usually
		2945	preferred, because it is much easier and cleaner, at the expense of having
		2946	to have another binary.
2515		2947
2516		2948
2517	=head1 SECURITY CONSIDERATIONS	2949	=head1 SECURITY CONSIDERATIONS
2518		2950
2519	AnyEvent can be forced to load any event model via	2951	AnyEvent can be forced to load any event model via
…		…
2549	pronounced).	2981	pronounced).
2550		2982
2551		2983
2552	=head1 SEE ALSO	2984	=head1 SEE ALSO
2553		2985
2554	Utility functions: L<AnyEvent::Util>.	2986	Tutorial/Introduction: L<AnyEvent::Intro>.
2555		2987
2556	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2988	FAQ: L<AnyEvent::FAQ>.
2557	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2989
		2990	Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
		2991	(simply logging).
		2992
		2993	Development/Debugging: L<AnyEvent::Strict> (stricter checking),
		2994	L<AnyEvent::Debug> (interactive shell, watcher tracing).
		2995
		2996	Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
		2997	L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
		2998	L<Qt>, L<POE>, L<FLTK>.
2558		2999
2559	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	3000	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2560	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	3001	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2561	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	3002	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2562	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.	3003	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
		3004	L<AnyEvent::Impl::FLTK>.
2563		3005
2564	Non-blocking file handles, sockets, TCP clients and	3006	Non-blocking handles, pipes, stream sockets, TCP clients and
2565	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	3007	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2566		3008
2567	Asynchronous DNS: L<AnyEvent::DNS>.	3009	Asynchronous DNS: L<AnyEvent::DNS>.
2568		3010
2569	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	3011	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2570	L<Coro::Event>,
2571		3012
2572	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	3013	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2573	L<AnyEvent::HTTP>.	3014	L<AnyEvent::HTTP>.
2574		3015
2575		3016
2576	=head1 AUTHOR	3017	=head1 AUTHOR
2577		3018

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