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Revision 1.296 by root, Tue Nov 17 01:19:49 2009 UTC vs.
Revision 1.410 by root, Fri Mar 1 06:03:21 2013 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 L<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) });
…		…
725	};	763	};
726	}	764	}
727		765
728	$cv->end;	766	$cv->end;
729		767
		768	...
		769
		770	my $results = $cv->recv;
		771
730	This code fragment supposedly pings a number of hosts and calls	772	This code fragment supposedly pings a number of hosts and calls
731	C<send> after results for all then have have been gathered - in any	773	C<send> after results for all then have have been gathered - in any
732	order. To achieve this, the code issues a call to C<begin> when it starts	774	order. To achieve this, the code issues a call to C<begin> when it starts
733	each ping request and calls C<end> when it has received some result for	775	each ping request and calls C<end> when it has received some result for
734	it. Since C<begin> and C<end> only maintain a counter, the order in which	776	it. Since C<begin> and C<end> only maintain a counter, the order in which
…		…
739	to be called once the counter reaches C<0>, and second, it ensures that	781	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	782	C<send> is called even when C<no> hosts are being pinged (the loop
741	doesn't execute once).	783	doesn't execute once).
742		784
743	This is the general pattern when you "fan out" into multiple (but	785	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	786	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	787	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,	788	subrequest you start, call C<begin> and for each subrequest you finish,
747	call C<end>.	789	call C<end>.
748		790
749	=back	791	=back
…		…
756	=over 4	798	=over 4
757		799
758	=item $cv->recv	800	=item $cv->recv
759		801
760	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	802	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
761	>> methods have been called on c<$cv>, while servicing other watchers	803	>> methods have been called on C<$cv>, while servicing other watchers
762	normally.	804	normally.
763		805
764	You can only wait once on a condition - additional calls are valid but	806	You can only wait once on a condition - additional calls are valid but
765	will return immediately.	807	will return immediately.
766		808
…		…
769		811
770	In list context, all parameters passed to C<send> will be returned,	812	In list context, all parameters passed to C<send> will be returned,
771	in scalar context only the first one will be returned.	813	in scalar context only the first one will be returned.
772		814
773	Note that doing a blocking wait in a callback is not supported by any	815	Note that doing a blocking wait in a callback is not supported by any
774	event loop, that is, recursive invocation of a blocking C<< ->recv	816	event loop, that is, recursive invocation of a blocking C<< ->recv >> is
775	>> is not allowed, and the C<recv> call will C<croak> if such a	817	not allowed and the C<recv> call will C<croak> if such a condition is
776	condition is detected. This condition can be slightly loosened by using	818	detected. This requirement can be dropped by relying on L<Coro::AnyEvent>
777	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from	819	, which allows you to do a blocking C<< ->recv >> from any thread
778	any thread that doesn't run the event loop itself.	820	that doesn't run the event loop itself. L<Coro::AnyEvent> is loaded
		821	automatically when L<Coro> is used with L<AnyEvent>, so code does not need
		822	to do anything special to take advantage of that: any code that would
		823	normally block your program because it calls C<recv>, be executed in an
		824	C<async> thread instead without blocking other threads.
779		825
780	Not all event models support a blocking wait - some die in that case	826	Not all event models support a blocking wait - some die in that case
781	(programs might want to do that to stay interactive), so I<if you are	827	(programs might want to do that to stay interactive), so I<if you are
782	using this from a module, never require a blocking wait>. Instead, let the	828	using this from a module, never require a blocking wait>. Instead, let the
783	caller decide whether the call will block or not (for example, by coupling	829	caller decide whether the call will block or not (for example, by coupling
784	condition variables with some kind of request results and supporting	830	condition variables with some kind of request results and supporting
785	callbacks so the caller knows that getting the result will not block,	831	callbacks so the caller knows that getting the result will not block,
786	while still supporting blocking waits if the caller so desires).	832	while still supporting blocking waits if the caller so desires).
787		833
788	You can ensure that C<< -recv >> never blocks by setting a callback and	834	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	835	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	836	time). This will work even when the event loop does not support blocking
791	waits otherwise.	837	waits otherwise.
792		838
793	=item $bool = $cv->ready	839	=item $bool = $cv->ready
…		…
798	=item $cb = $cv->cb ($cb->($cv))	844	=item $cb = $cv->cb ($cb->($cv))
799		845
800	This is a mutator function that returns the callback set and optionally	846	This is a mutator function that returns the callback set and optionally
801	replaces it before doing so.	847	replaces it before doing so.
802		848
803	The callback will be called when the condition becomes (or already was)	849	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	850	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>	851	condition variable itself. If the condition is already true, the
		852	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.	853	the callback or at any later time is guaranteed not to block.
807		854
808	=back	855	=back
809		856
810	=head1 SUPPORTED EVENT LOOPS/BACKENDS	857	=head1 SUPPORTED EVENT LOOPS/BACKENDS
811		858
…		…
819	use. If EV is not installed, then AnyEvent will fall back to its own	866	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	867	pure-perl implementation, which is available everywhere as it comes with
821	AnyEvent itself.	868	AnyEvent itself.
822		869
823	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	870	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
824	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	871	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
825		872
826	=item Backends that are transparently being picked up when they are used.	873	=item Backends that are transparently being picked up when they are used.
827		874
828	These will be used when they are currently loaded when the first watcher	875	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	876	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	877	them. This means that AnyEvent will automatically pick the right backend
831	when the main program loads an event module before anything starts to	878	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.	879	create watchers. Nothing special needs to be done by the main program.
833		880
…		…
835	AnyEvent::Impl::Glib based on Glib, slow but very stable.	882	AnyEvent::Impl::Glib based on Glib, slow but very stable.
836	AnyEvent::Impl::Tk based on Tk, very broken.	883	AnyEvent::Impl::Tk based on Tk, very broken.
837	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	884	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
838	AnyEvent::Impl::POE based on POE, very slow, some limitations.	885	AnyEvent::Impl::POE based on POE, very slow, some limitations.
839	AnyEvent::Impl::Irssi used when running within irssi.	886	AnyEvent::Impl::Irssi used when running within irssi.
		887	AnyEvent::Impl::IOAsync based on IO::Async.
		888	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
		889	AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding).
840		890
841	=item Backends with special needs.	891	=item Backends with special needs.
842		892
843	Qt requires the Qt::Application to be instantiated first, but will	893	Qt requires the Qt::Application to be instantiated first, but will
844	otherwise be picked up automatically. As long as the main program	894	otherwise be picked up automatically. As long as the main program
845	instantiates the application before any AnyEvent watchers are created,	895	instantiates the application before any AnyEvent watchers are created,
846	everything should just work.	896	everything should just work.
847		897
848	AnyEvent::Impl::Qt based on Qt.	898	AnyEvent::Impl::Qt based on Qt.
849		899
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.	900	=item Event loops that are indirectly supported via other backends.
859		901
860	Some event loops can be supported via other modules:	902	Some event loops can be supported via other modules:
861		903
862	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.	904	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	929	Contains C<undef> until the first watcher is being created, before the
888	backend has been autodetected.	930	backend has been autodetected.
889		931
890	Afterwards it contains the event model that is being used, which is the	932	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	933	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	934	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	935	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
894	will be C<urxvt::anyevent>).	936	will be C<urxvt::anyevent>).
895		937
896	=item AnyEvent::detect	938	=item AnyEvent::detect
897		939
898	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	940	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
899	if necessary. You should only call this function right before you would	941	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	942	have created an AnyEvent watcher anyway, that is, as late as possible at
901	runtime, and not e.g. while initialising of your module.	943	runtime, and not e.g. during initialisation of your module.
		944
		945	The effect of calling this function is as if a watcher had been created
		946	(specifically, actions that happen "when the first watcher is created"
		947	happen when calling detetc as well).
902		948
903	If you need to do some initialisation before AnyEvent watchers are	949	If you need to do some initialisation before AnyEvent watchers are
904	created, use C<post_detect>.	950	created, use C<post_detect>.
905		951
906	=item $guard = AnyEvent::post_detect { BLOCK }	952	=item $guard = AnyEvent::post_detect { BLOCK }
907		953
908	Arranges for the code block to be executed as soon as the event model is	954	Arranges for the code block to be executed as soon as the event model is
909	autodetected (or immediately if this has already happened).	955	autodetected (or immediately if that has already happened).
910		956
911	The block will be executed I<after> the actual backend has been detected	957	The block will be executed I<after> the actual backend has been detected
912	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	958	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
913	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	959	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
914	other initialisations - see the sources of L<AnyEvent::Strict> or	960	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
923	that automatically removes the callback again when it is destroyed (or	969	that automatically removes the callback again when it is destroyed (or
924	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for	970	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
925	a case where this is useful.	971	a case where this is useful.
926		972
927	Example: Create a watcher for the IO::AIO module and store it in	973	Example: Create a watcher for the IO::AIO module and store it in
928	C<$WATCHER>. Only do so after the event loop is initialised, though.	974	C<$WATCHER>, but do so only do so after the event loop is initialised.
929		975
930	our WATCHER;	976	our WATCHER;
931		977
932	my $guard = AnyEvent::post_detect {	978	my $guard = AnyEvent::post_detect {
933	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);	979	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
…		…
941	$WATCHER ||= $guard;	987	$WATCHER ||= $guard;
942		988
943	=item @AnyEvent::post_detect	989	=item @AnyEvent::post_detect
944		990
945	If there are any code references in this array (you can C<push> to it	991	If there are any code references in this array (you can C<push> to it
946	before or after loading AnyEvent), then they will called directly after	992	before or after loading AnyEvent), then they will be called directly
947	the event loop has been chosen.	993	after the event loop has been chosen.
948		994
949	You should check C<$AnyEvent::MODEL> before adding to this array, though:	995	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	996	if it is defined then the event loop has already been detected, and the
951	array will be ignored.	997	array will be ignored.
952		998
953	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	999	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
954	it,as it takes care of these details.	1000	it, as it takes care of these details.
955		1001
956	This variable is mainly useful for modules that can do something useful	1002	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	1003	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	1004	not need to even load it by default. This array provides the means to hook
959	into AnyEvent passively, without loading it.	1005	into AnyEvent passively, without loading it.
960		1006
		1007	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1008	together, you could put this into Coro (this is the actual code used by
		1009	Coro to accomplish this):
		1010
		1011	if (defined $AnyEvent::MODEL) {
		1012	# AnyEvent already initialised, so load Coro::AnyEvent
		1013	require Coro::AnyEvent;
		1014	} else {
		1015	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1016	# as soon as it is
		1017	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1018	}
		1019
		1020	=item AnyEvent::postpone { BLOCK }
		1021
		1022	Arranges for the block to be executed as soon as possible, but not before
		1023	the call itself returns. In practise, the block will be executed just
		1024	before the event loop polls for new events, or shortly afterwards.
		1025
		1026	This function never returns anything (to make the C<return postpone { ...
		1027	}> idiom more useful.
		1028
		1029	To understand the usefulness of this function, consider a function that
		1030	asynchronously does something for you and returns some transaction
		1031	object or guard to let you cancel the operation. For example,
		1032	C<AnyEvent::Socket::tcp_connect>:
		1033
		1034	# start a conenction attempt unless one is active
		1035	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1036	delete $self->{connect_guard};
		1037	...
		1038	};
		1039
		1040	Imagine that this function could instantly call the callback, for
		1041	example, because it detects an obvious error such as a negative port
		1042	number. Invoking the callback before the function returns causes problems
		1043	however: the callback will be called and will try to delete the guard
		1044	object. But since the function hasn't returned yet, there is nothing to
		1045	delete. When the function eventually returns it will assign the guard
		1046	object to C<< $self->{connect_guard} >>, where it will likely never be
		1047	deleted, so the program thinks it is still trying to connect.
		1048
		1049	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1050	callback directly on error:
		1051
		1052	$cb->(undef), return # signal error to callback, BAD!
		1053	if $some_error_condition;
		1054
		1055	It should use C<postpone>:
		1056
		1057	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1058	if $some_error_condition;
		1059
		1060	=item AnyEvent::log $level, $msg[, @args]
		1061
		1062	Log the given C<$msg> at the given C<$level>.
		1063
		1064	If L<AnyEvent::Log> is not loaded then this function makes a simple test
		1065	to see whether the message will be logged. If the test succeeds it will
		1066	load AnyEvent::Log and call C<AnyEvent::Log::log> - consequently, look at
		1067	the L<AnyEvent::Log> documentation for details.
		1068
		1069	If the test fails it will simply return. Right now this happens when a
		1070	numerical loglevel is used and it is larger than the level specified via
		1071	C<$ENV{PERL_ANYEVENT_VERBOSE}>.
		1072
		1073	If you want to sprinkle loads of logging calls around your code, consider
		1074	creating a logger callback with the C<AnyEvent::Log::logger> function,
		1075	which can reduce typing, codesize and can reduce the logging overhead
		1076	enourmously.
		1077
961	=back	1078	=back
962		1079
963	=head1 WHAT TO DO IN A MODULE	1080	=head1 WHAT TO DO IN A MODULE
964		1081
965	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1082	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	1092	because it will stall the whole program, and the whole point of using
976	events is to stay interactive.	1093	events is to stay interactive.
977		1094
978	It is fine, however, to call C<< ->recv >> when the user of your module	1095	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	1096	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 >>	1097	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).	1098	freely, as the user of your module knows what she is doing. Always).
982		1099
983	=head1 WHAT TO DO IN THE MAIN PROGRAM	1100	=head1 WHAT TO DO IN THE MAIN PROGRAM
984		1101
985	There will always be a single main program - the only place that should	1102	There will always be a single main program - the only place that should
986	dictate which event model to use.	1103	dictate which event model to use.
987		1104
988	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1105	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	1106	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.	1107	uses AnyEvent, but does not care which event loop is used, all it needs
		1108	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1109	available loop implementation.
991		1110
992	If the main program relies on a specific event model - for example, in	1111	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	1112	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	1113	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	1114	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	1115	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	1116	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.	1117	might choose the wrong one unless you load the correct one yourself.
999		1118
1000	You can chose to use a pure-perl implementation by loading the	1119	You can chose to use a pure-perl implementation by loading the
1001	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1120	C<AnyEvent::Loop> module, which gives you similar behaviour
1002	everywhere, but letting AnyEvent chose the model is generally better.	1121	everywhere, but letting AnyEvent chose the model is generally better.
1003		1122
1004	=head2 MAINLOOP EMULATION	1123	=head2 MAINLOOP EMULATION
1005		1124
1006	Sometimes (often for short test scripts, or even standalone programs who	1125	Sometimes (often for short test scripts, or even standalone programs who
…		…
1019		1138
1020		1139
1021	=head1 OTHER MODULES	1140	=head1 OTHER MODULES
1022		1141
1023	The following is a non-exhaustive list of additional modules that use	1142	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	1143	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	1144	AnyEvent modules and other event loops in the same program. Some of the
1026	come with AnyEvent, most are available via CPAN.	1145	modules come as part of AnyEvent, the others are available via CPAN (see
		1146	L<http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for
		1147	a longer non-exhaustive list), and the list is heavily biased towards
		1148	modules of the AnyEvent author himself :)
1027		1149
1028	=over 4	1150	=over 4
1029		1151
1030	=item L<AnyEvent::Util>	1152	=item L<AnyEvent::Util>
1031		1153
1032	Contains various utility functions that replace often-used but blocking	1154	Contains various utility functions that replace often-used blocking
1033	functions such as C<inet_aton> by event-/callback-based versions.	1155	functions such as C<inet_aton> with event/callback-based versions.
1034		1156
1035	=item L<AnyEvent::Socket>	1157	=item L<AnyEvent::Socket>
1036		1158
1037	Provides various utility functions for (internet protocol) sockets,	1159	Provides various utility functions for (internet protocol) sockets,
1038	addresses and name resolution. Also functions to create non-blocking tcp	1160	addresses and name resolution. Also functions to create non-blocking tcp
…		…
1040		1162
1041	=item L<AnyEvent::Handle>	1163	=item L<AnyEvent::Handle>
1042		1164
1043	Provide read and write buffers, manages watchers for reads and writes,	1165	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	1166	supports raw and formatted I/O, I/O queued and fully transparent and
1045	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1167	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1046		1168
1047	=item L<AnyEvent::DNS>	1169	=item L<AnyEvent::DNS>
1048		1170
1049	Provides rich asynchronous DNS resolver capabilities.	1171	Provides rich asynchronous DNS resolver capabilities.
1050		1172
		1173	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1174
		1175	Implement event-based interfaces to the protocols of the same name (for
		1176	the curious, IGS is the International Go Server and FCP is the Freenet
		1177	Client Protocol).
		1178
1051	=item L<AnyEvent::HTTP>	1179	=item L<AnyEvent::AIO>
1052		1180
1053	A simple-to-use HTTP library that is capable of making a lot of concurrent	1181	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
1054	HTTP requests.	1182	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1183	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1184	file I/O, and much more.
		1185
		1186	=item L<AnyEvent::Filesys::Notify>
		1187
		1188	AnyEvent is good for non-blocking stuff, but it can't detect file or
		1189	path changes (e.g. "watch this directory for new files", "watch this
		1190	file for changes"). The L<AnyEvent::Filesys::Notify> module promises to
		1191	do just that in a portbale fashion, supporting inotify on GNU/Linux and
		1192	some weird, without doubt broken, stuff on OS X to monitor files. It can
		1193	fall back to blocking scans at regular intervals transparently on other
		1194	platforms, so it's about as portable as it gets.
		1195
		1196	(I haven't used it myself, but I haven't heard anybody complaining about
		1197	it yet).
		1198
		1199	=item L<AnyEvent::DBI>
		1200
		1201	Executes L<DBI> requests asynchronously in a proxy process for you,
		1202	notifying you in an event-based way when the operation is finished.
1055		1203
1056	=item L<AnyEvent::HTTPD>	1204	=item L<AnyEvent::HTTPD>
1057		1205
1058	Provides a simple web application server framework.	1206	A simple embedded webserver.
1059		1207
1060	=item L<AnyEvent::FastPing>	1208	=item L<AnyEvent::FastPing>
1061		1209
1062	The fastest ping in the west.	1210	The fastest ping in the west.
1063		1211
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>	1212	=item L<Coro>
1107		1213
1108	Has special support for AnyEvent via L<Coro::AnyEvent>.	1214	Has special support for AnyEvent via L<Coro::AnyEvent>, which allows you
		1215	to simply invert the flow control - don't call us, we will call you:
		1216
		1217	async {
		1218	Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
		1219	print "5 seconds later!\n";
		1220
		1221	Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
		1222	my $line = <STDIN>; # works for ttys
		1223
		1224	AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
		1225	my ($body, $hdr) = Coro::rouse_wait;
		1226	};
1109		1227
1110	=back	1228	=back
1111		1229
1112	=cut	1230	=cut
1113		1231
1114	package AnyEvent;	1232	package AnyEvent;
1115		1233
1116	# basically a tuned-down version of common::sense	1234	# basically a tuned-down version of common::sense
1117	sub common_sense {	1235	sub common_sense {
1118	# from common:.sense 1.0	1236	# from common:.sense 3.5
		1237	local $^W;
1119	${^WARNING_BITS} = "\xfc\x3f\xf3\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x03";	1238	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1120	# use strict vars subs	1239	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1121	$^H |= 0x00000600;	1240	$^H |= 0x00000600;
1122	}	1241	}
1123		1242
1124	BEGIN { AnyEvent::common_sense }	1243	BEGIN { AnyEvent::common_sense }
1125		1244
1126	use Carp ();	1245	use Carp ();
1127		1246
1128	our $VERSION = '5.202';	1247	our $VERSION = '7.04';
1129	our $MODEL;	1248	our $MODEL;
1130
1131	our $AUTOLOAD;
1132	our @ISA;	1249	our @ISA;
1133
1134	our @REGISTRY;	1250	our @REGISTRY;
1135
1136	our $WIN32;
1137
1138	our $VERBOSE;	1251	our $VERBOSE;
		1252	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
		1253	our $MAX_SIGNAL_LATENCY = $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} || 10; # executes after the BEGIN block below (tainting!)
1139		1254
1140	BEGIN {	1255	BEGIN {
1141	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1256	require "AnyEvent/constants.pl";
		1257
1142	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1258	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1143		1259
1144	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1260	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1145	if ${^TAINT};	1261	if ${^TAINT};
1146		1262
1147	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1263	$ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
		1264	for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
1148		1265
1149	}	1266	@ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
		1267	if ${^TAINT};
1150		1268
1151	our $MAX_SIGNAL_LATENCY = 10;	1269	# $ENV{PERL_ANYEVENT_xxx} now valid
1152		1270
1153	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1271	$VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 4;
1154		1272
1155	{
1156	my $idx;	1273	my $idx;
1157	$PROTOCOL{$_} = ++$idx	1274	$PROTOCOL{$_} = ++$idx
1158	for reverse split /\s*,\s*/,	1275	for reverse split /\s*,\s*/,
1159	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1276	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1160	}	1277	}
1161		1278
		1279	our @post_detect;
		1280
		1281	sub post_detect(&) {
		1282	my ($cb) = @_;
		1283
		1284	push @post_detect, $cb;
		1285
		1286	defined wantarray
		1287	? bless \$cb, "AnyEvent::Util::postdetect"
		1288	: ()
		1289	}
		1290
		1291	sub AnyEvent::Util::postdetect::DESTROY {
		1292	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1293	}
		1294
		1295	our $POSTPONE_W;
		1296	our @POSTPONE;
		1297
		1298	sub _postpone_exec {
		1299	undef $POSTPONE_W;
		1300
		1301	&{ shift @POSTPONE }
		1302	while @POSTPONE;
		1303	}
		1304
		1305	sub postpone(&) {
		1306	push @POSTPONE, shift;
		1307
		1308	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1309
		1310	()
		1311	}
		1312
		1313	sub log($$;@) {
		1314	# only load the big bloated module when we actually are about to log something
		1315	if ($_[0] <= ($VERBOSE || 1)) { # also catches non-numeric levels(!) and fatal
		1316	local ($!, $@);
		1317	require AnyEvent::Log; # among other things, sets $VERBOSE to 9
		1318	# AnyEvent::Log overwrites this function
		1319	goto &log;
		1320	}
		1321
		1322	0 # not logged
		1323	}
		1324
		1325	sub _logger($;$) {
		1326	my ($level, $renabled) = @_;
		1327
		1328	$$renabled = $level <= $VERBOSE;
		1329
		1330	my $logger = [(caller)[0], $level, $renabled];
		1331
		1332	$AnyEvent::Log::LOGGER{$logger+0} = $logger;
		1333
		1334	# return unless defined wantarray;
		1335	#
		1336	# require AnyEvent::Util;
		1337	# my $guard = AnyEvent::Util::guard (sub {
		1338	# # "clean up"
		1339	# delete $LOGGER{$logger+0};
		1340	# });
		1341	#
		1342	# sub {
		1343	# return 0 unless $$renabled;
		1344	#
		1345	# $guard if 0; # keep guard alive, but don't cause runtime overhead
		1346	# require AnyEvent::Log unless $AnyEvent::Log::VERSION;
		1347	# package AnyEvent::Log;
		1348	# _log ($logger->[0], $level, @_) # logger->[0] has been converted at load time
		1349	# }
		1350	}
		1351
		1352	if (length $ENV{PERL_ANYEVENT_LOG}) {
		1353	require AnyEvent::Log; # AnyEvent::Log does the thing for us
		1354	}
		1355
1162	my @models = (	1356	our @models = (
1163	[EV:: => AnyEvent::Impl::EV:: , 1],	1357	[EV:: => AnyEvent::Impl::EV::],
1164	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],	1358	[AnyEvent::Loop:: => AnyEvent::Impl::Perl::],
1165	# everything below here will not (normally) be autoprobed	1359	# everything below here will not (normally) be autoprobed
1166	# as the pureperl backend should work everywhere	1360	# as the pure perl backend should work everywhere
1167	# and is usually faster	1361	# and is usually faster
		1362	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package, so msut be near the top
1168	[Event:: => AnyEvent::Impl::Event::, 1],	1363	[Event:: => AnyEvent::Impl::Event::], # slow, stable
1169	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers	1364	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
		1365	# everything below here should not be autoloaded
1170	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1366	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1171	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1172	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1367	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1173	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1368	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1174	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1369	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1175	[Wx:: => AnyEvent::Impl::POE::],	1370	[Wx:: => AnyEvent::Impl::POE::],
1176	[Prima:: => AnyEvent::Impl::POE::],	1371	[Prima:: => AnyEvent::Impl::POE::],
1177	# IO::Async is just too broken - we would need workarounds for its	1372	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1178	# byzantine signal and broken child handling, among others.	1373	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1179	# IO::Async is rather hard to detect, as it doesn't have any	1374	[FLTK:: => AnyEvent::Impl::FLTK::],
1180	# obvious default class.
1181	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1182	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1183	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1184	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1185	);	1375	);
1186		1376
1187	our %method = map +($_ => 1),	1377	our @isa_hook;
		1378
		1379	sub _isa_set {
		1380	my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
		1381
		1382	@{"$pkg[$_-1]::ISA"} = $pkg[$_]
		1383	for 1 .. $#pkg;
		1384
		1385	grep $_ && $_->[1], @isa_hook
		1386	and AE::_reset ();
		1387	}
		1388
		1389	# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
		1390	sub _isa_hook($$;$) {
		1391	my ($i, $pkg, $reset_ae) = @_;
		1392
		1393	$isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
		1394
		1395	_isa_set;
		1396	}
		1397
		1398	# all autoloaded methods reserve the complete glob, not just the method slot.
		1399	# due to bugs in perls method cache implementation.
1188	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1400	our @methods = qw(io timer time now now_update signal child idle condvar);
1189		1401
1190	our @post_detect;
1191
1192	sub post_detect(&) {	1402	sub detect() {
1193	my ($cb) = @_;	1403	return $MODEL if $MODEL; # some programs keep references to detect
1194		1404
1195	if ($MODEL) {	1405	# IO::Async::Loop::AnyEvent is extremely evil, refuse to work with it
1196	$cb->();	1406	# the author knows about the problems and what it does to AnyEvent as a whole
		1407	# (and the ability of others to use AnyEvent), but simply wants to abuse AnyEvent
		1408	# anyway.
		1409	AnyEvent::log fatal => "IO::Async::Loop::AnyEvent detected - that module is broken by\n"
		1410	. "design, abuses internals and breaks AnyEvent - will not continue."
		1411	if exists $INC{"IO/Async/Loop/AnyEvent.pm"};
1197		1412
1198	undef	1413	local $!; # for good measure
		1414	local $SIG{__DIE__}; # we use eval
		1415
		1416	# free some memory
		1417	*detect = sub () { $MODEL };
		1418	# undef &func doesn't correctly update the method cache. grmbl.
		1419	# so we delete the whole glob. grmbl.
		1420	# otoh, perl doesn't let me undef an active usb, but it lets me free
		1421	# a glob with an active sub. hrm. i hope it works, but perl is
		1422	# usually buggy in this department. sigh.
		1423	delete @{"AnyEvent::"}{@methods};
		1424	undef @methods;
		1425
		1426	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1427	my $model = $1;
		1428	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1429	if (eval "require $model") {
		1430	AnyEvent::log 7 => "Loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.";
		1431	$MODEL = $model;
1199	} else {	1432	} else {
1200	push @post_detect, $cb;	1433	AnyEvent::log 4 => "Unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1201		1434	}
1202	defined wantarray
1203	? bless \$cb, "AnyEvent::Util::postdetect"
1204	: ()
1205	}	1435	}
1206	}
1207		1436
1208	sub AnyEvent::Util::postdetect::DESTROY {	1437	# check for already loaded models
1209	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1210	}
1211
1212	sub detect() {
1213	unless ($MODEL) {	1438	unless ($MODEL) {
1214	local $SIG{__DIE__};	1439	for (@REGISTRY, @models) {
1215		1440	my ($package, $model) = @$_;
1216	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1441	if (${"$package\::VERSION"} > 0) {
1217	my $model = "AnyEvent::Impl::$1";
1218	if (eval "require $model") {	1442	if (eval "require $model") {
		1443	AnyEvent::log 7 => "Autodetected model '$model', using it.";
1219	$MODEL = $model;	1444	$MODEL = $model;
1220	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1445	last;
1221	} else {	1446	} else {
1222	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1447	AnyEvent::log 8 => "Detected event loop $package, but cannot load '$model', skipping: $@";
		1448	}
1223	}	1449	}
1224	}	1450	}
1225		1451
1226	# check for already loaded models
1227	unless ($MODEL) {	1452	unless ($MODEL) {
		1453	# try to autoload a model
1228	for (@REGISTRY, @models) {	1454	for (@REGISTRY, @models) {
1229	my ($package, $model) = @$_;	1455	my ($package, $model) = @$_;
		1456	if (
		1457	eval "require $package"
1230	if (${"$package\::VERSION"} > 0) {	1458	and ${"$package\::VERSION"} > 0
1231	if (eval "require $model") {	1459	and eval "require $model"
		1460	) {
		1461	AnyEvent::log 7 => "Autoloaded model '$model', using it.";
1232	$MODEL = $model;	1462	$MODEL = $model;
1233	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1234	last;	1463	last;
1235	}
1236	}	1464	}
1237	}	1465	}
1238		1466
1239	unless ($MODEL) {
1240	# try to autoload a model
1241	for (@REGISTRY, @models) {
1242	my ($package, $model, $autoload) = @$_;
1243	if (
1244	$autoload
1245	and eval "require $package"
1246	and ${"$package\::VERSION"} > 0
1247	and eval "require $model"
1248	) {
1249	$MODEL = $model;
1250	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1251	last;
1252	}
1253	}
1254
1255	$MODEL	1467	$MODEL
1256	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1468	or AnyEvent::log fatal => "Backend autodetection failed - did you properly install AnyEvent?";
1257	}
1258	}	1469	}
1259
1260	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1261
1262	unshift @ISA, $MODEL;
1263
1264	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1265
1266	(shift @post_detect)->() while @post_detect;
1267	}	1470	}
1268		1471
		1472	# free memory only needed for probing
		1473	undef @models;
		1474	undef @REGISTRY;
		1475
		1476	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1477
		1478	# now nuke some methods that are overridden by the backend.
		1479	# SUPER usage is not allowed in these.
		1480	for (qw(time signal child idle)) {
		1481	undef &{"AnyEvent::Base::$_"}
		1482	if defined &{"$MODEL\::$_"};
		1483	}
		1484
		1485	_isa_set;
		1486
		1487	# we're officially open!
		1488
		1489	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1490	require AnyEvent::Strict;
		1491	}
		1492
		1493	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1494	require AnyEvent::Debug;
		1495	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1496	}
		1497
		1498	if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1499	require AnyEvent::Socket;
		1500	require AnyEvent::Debug;
		1501
		1502	my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
		1503	$shell =~ s/\$\$/$$/g;
		1504
		1505	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1506	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1507	}
		1508
		1509	# now the anyevent environment is set up as the user told us to, so
		1510	# call the actual user code - post detects
		1511
		1512	(shift @post_detect)->() while @post_detect;
		1513	undef @post_detect;
		1514
		1515	*post_detect = sub(&) {
		1516	shift->();
		1517
		1518	undef
		1519	};
		1520
1269	$MODEL	1521	$MODEL
1270	}	1522	}
1271		1523
1272	sub AUTOLOAD {	1524	for my $name (@methods) {
1273	(my $func = $AUTOLOAD) =~ s/.*://;	1525	*$name = sub {
1274		1526	detect;
1275	$method{$func}	1527	# we use goto because
1276	or Carp::croak "$func: not a valid method for AnyEvent objects";	1528	# a) it makes the thunk more transparent
1277		1529	# b) it allows us to delete the thunk later
1278	detect unless $MODEL;	1530	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1279		1531	};
1280	my $class = shift;
1281	$class->$func (@_);
1282	}	1532	}
1283		1533
1284	# utility function to dup a filehandle. this is used by many backends	1534	# utility function to dup a filehandle. this is used by many backends
1285	# to support binding more than one watcher per filehandle (they usually	1535	# to support binding more than one watcher per filehandle (they usually
1286	# allow only one watcher per fd, so we dup it to get a different one).	1536	# allow only one watcher per fd, so we dup it to get a different one).
…		…
1300		1550
1301	=head1 SIMPLIFIED AE API	1551	=head1 SIMPLIFIED AE API
1302		1552
1303	Starting with version 5.0, AnyEvent officially supports a second, much	1553	Starting with version 5.0, AnyEvent officially supports a second, much
1304	simpler, API that is designed to reduce the calling, typing and memory	1554	simpler, API that is designed to reduce the calling, typing and memory
1305	overhead.	1555	overhead by using function call syntax and a fixed number of parameters.
1306		1556
1307	See the L<AE> manpage for details.	1557	See the L<AE> manpage for details.
1308		1558
1309	=cut	1559	=cut
1310		1560
1311	package AE;	1561	package AE;
1312		1562
1313	our $VERSION = $AnyEvent::VERSION;	1563	our $VERSION = $AnyEvent::VERSION;
1314		1564
		1565	sub _reset() {
		1566	eval q{
		1567	# fall back to the main API by default - backends and AnyEvent::Base
		1568	# implementations can overwrite these.
		1569
1315	sub io($$$) {	1570	sub io($$$) {
1316	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])	1571	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1317	}	1572	}
1318		1573
1319	sub timer($$$) {	1574	sub timer($$$) {
1320	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])	1575	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1321	}	1576	}
1322		1577
1323	sub signal($$) {	1578	sub signal($$) {
1324	AnyEvent->signal (signal => $_[0], cb => $_[1])	1579	AnyEvent->signal (signal => $_[0], cb => $_[1])
1325	}	1580	}
1326		1581
1327	sub child($$) {	1582	sub child($$) {
1328	AnyEvent->child (pid => $_[0], cb => $_[1])	1583	AnyEvent->child (pid => $_[0], cb => $_[1])
1329	}	1584	}
1330		1585
1331	sub idle($) {	1586	sub idle($) {
1332	AnyEvent->idle (cb => $_[0])	1587	AnyEvent->idle (cb => $_[0]);
1333	}	1588	}
1334		1589
1335	sub cv(;&) {	1590	sub cv(;&) {
1336	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())	1591	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1337	}	1592	}
1338		1593
1339	sub now() {	1594	sub now() {
1340	AnyEvent->now	1595	AnyEvent->now
1341	}	1596	}
1342		1597
1343	sub now_update() {	1598	sub now_update() {
1344	AnyEvent->now_update	1599	AnyEvent->now_update
1345	}	1600	}
1346		1601
1347	sub time() {	1602	sub time() {
1348	AnyEvent->time	1603	AnyEvent->time
		1604	}
		1605
		1606	*postpone = \&AnyEvent::postpone;
		1607	*log = \&AnyEvent::log;
		1608	};
		1609	die if $@;
1349	}	1610	}
		1611
		1612	BEGIN { _reset }
1350		1613
1351	package AnyEvent::Base;	1614	package AnyEvent::Base;
1352		1615
1353	# default implementations for many methods	1616	# default implementations for many methods
1354		1617
1355	sub _time() {	1618	sub time {
		1619	eval q{ # poor man's autoloading {}
1356	# probe for availability of Time::HiRes	1620	# probe for availability of Time::HiRes
1357	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1621	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1358	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1622	*time = sub { Time::HiRes::time () };
1359	*_time = \&Time::HiRes::time;	1623	*AE::time = \& Time::HiRes::time ;
		1624	*now = \&time;
		1625	AnyEvent::log 8 => "using Time::HiRes for sub-second timing accuracy.";
1360	# if (eval "use POSIX (); (POSIX::times())...	1626	# if (eval "use POSIX (); (POSIX::times())...
1361	} else {	1627	} else {
1362	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1628	*time = sub { CORE::time };
1363	*_time = sub { time }; # epic fail	1629	*AE::time = sub (){ CORE::time };
		1630	*now = \&time;
		1631	AnyEvent::log 3 => "Using built-in time(), no sub-second resolution!";
		1632	}
1364	}	1633	};
		1634	die if $@;
1365		1635
1366	&_time	1636	&time
1367	}	1637	}
1368		1638
1369	sub time { _time }	1639	*now = \&time;
1370	sub now { _time }
1371	sub now_update { }	1640	sub now_update { }
1372		1641
		1642	sub _poll {
		1643	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1644	}
		1645
1373	# default implementation for ->condvar	1646	# default implementation for ->condvar
		1647	# in fact, the default should not be overwritten
1374		1648
1375	sub condvar {	1649	sub condvar {
		1650	eval q{ # poor man's autoloading {}
		1651	*condvar = sub {
1376	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1652	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1653	};
		1654
		1655	*AE::cv = sub (;&) {
		1656	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1657	};
		1658	};
		1659	die if $@;
		1660
		1661	&condvar
1377	}	1662	}
1378		1663
1379	# default implementation for ->signal	1664	# default implementation for ->signal
1380		1665
1381	our $HAVE_ASYNC_INTERRUPT;	1666	our $HAVE_ASYNC_INTERRUPT;
…		…
1390		1675
1391	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1676	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1392	our (%SIG_ASY, %SIG_ASY_W);	1677	our (%SIG_ASY, %SIG_ASY_W);
1393	our ($SIG_COUNT, $SIG_TW);	1678	our ($SIG_COUNT, $SIG_TW);
1394		1679
1395	sub _signal_exec {
1396	$HAVE_ASYNC_INTERRUPT
1397	? $SIGPIPE_R->drain
1398	: sysread $SIGPIPE_R, (my $dummy), 9;
1399
1400	while (%SIG_EV) {
1401	for (keys %SIG_EV) {
1402	delete $SIG_EV{$_};
1403	$_->() for values %{ $SIG_CB{$_} || {} };
1404	}
1405	}
1406	}
1407
1408	# install a dummy wakeup watcher to reduce signal catching latency	1680	# install a dummy wakeup watcher to reduce signal catching latency
		1681	# used by Impls
1409	sub _sig_add() {	1682	sub _sig_add() {
1410	unless ($SIG_COUNT++) {	1683	unless ($SIG_COUNT++) {
1411	# try to align timer on a full-second boundary, if possible	1684	# try to align timer on a full-second boundary, if possible
1412	my $NOW = AE::now;	1685	my $NOW = AE::now;
1413		1686
…		…
1423	undef $SIG_TW	1696	undef $SIG_TW
1424	unless --$SIG_COUNT;	1697	unless --$SIG_COUNT;
1425	}	1698	}
1426		1699
1427	our $_sig_name_init; $_sig_name_init = sub {	1700	our $_sig_name_init; $_sig_name_init = sub {
1428	eval q{ # poor man's autoloading	1701	eval q{ # poor man's autoloading {}
1429	undef $_sig_name_init;	1702	undef $_sig_name_init;
1430		1703
1431	if (_have_async_interrupt) {	1704	if (_have_async_interrupt) {
1432	*sig2num = \&Async::Interrupt::sig2num;	1705	*sig2num = \&Async::Interrupt::sig2num;
1433	*sig2name = \&Async::Interrupt::sig2name;	1706	*sig2name = \&Async::Interrupt::sig2name;
…		…
1457		1730
1458	sub signal {	1731	sub signal {
1459	eval q{ # poor man's autoloading {}	1732	eval q{ # poor man's autoloading {}
1460	# probe for availability of Async::Interrupt	1733	# probe for availability of Async::Interrupt
1461	if (_have_async_interrupt) {	1734	if (_have_async_interrupt) {
1462	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;	1735	AnyEvent::log 8 => "Using Async::Interrupt for race-free signal handling.";
1463		1736
1464	$SIGPIPE_R = new Async::Interrupt::EventPipe;	1737	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1465	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;	1738	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1466		1739
1467	} else {	1740	} else {
1468	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;	1741	AnyEvent::log 8 => "Using emulated perl signal handling with latency timer.";
1469
1470	require Fcntl;
1471		1742
1472	if (AnyEvent::WIN32) {	1743	if (AnyEvent::WIN32) {
1473	require AnyEvent::Util;	1744	require AnyEvent::Util;
1474		1745
1475	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();	1746	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1476	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;	1747	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1477	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case	1748	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1478	} else {	1749	} else {
1479	pipe $SIGPIPE_R, $SIGPIPE_W;	1750	pipe $SIGPIPE_R, $SIGPIPE_W;
1480	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1751	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1481	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1752	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1482		1753
1483	# not strictly required, as $^F is normally 2, but let's make sure...	1754	# not strictly required, as $^F is normally 2, but let's make sure...
1484	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1755	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1485	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1756	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1486	}	1757	}
1487		1758
1488	$SIGPIPE_R	1759	$SIGPIPE_R
1489	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1760	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1490		1761
1491	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;	1762	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1492	}	1763	}
1493		1764
1494	*signal = sub {	1765	*signal = $HAVE_ASYNC_INTERRUPT
		1766	? sub {
1495	my (undef, %arg) = @_;	1767	my (undef, %arg) = @_;
1496		1768
1497	my $signal = uc $arg{signal}
1498	or Carp::croak "required option 'signal' is missing";
1499
1500	if ($HAVE_ASYNC_INTERRUPT) {
1501	# async::interrupt	1769	# async::interrupt
1502
1503	$signal = sig2num $signal;	1770	my $signal = sig2num $arg{signal};
1504	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1771	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1505		1772
1506	$SIG_ASY{$signal} ||= new Async::Interrupt	1773	$SIG_ASY{$signal} ||= new Async::Interrupt
1507	cb => sub { undef $SIG_EV{$signal} },	1774	cb => sub { undef $SIG_EV{$signal} },
1508	signal => $signal,	1775	signal => $signal,
1509	pipe => [$SIGPIPE_R->filenos],	1776	pipe => [$SIGPIPE_R->filenos],
1510	pipe_autodrain => 0,	1777	pipe_autodrain => 0,
1511	;	1778	;
1512		1779
1513	} else {	1780	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1781	}
		1782	: sub {
		1783	my (undef, %arg) = @_;
		1784
1514	# pure perl	1785	# pure perl
1515
1516	# AE::Util has been loaded in signal
1517	$signal = sig2name $signal;	1786	my $signal = sig2name $arg{signal};
1518	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1787	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1519		1788
1520	$SIG{$signal} ||= sub {	1789	$SIG{$signal} ||= sub {
1521	local $!;	1790	local $!;
1522	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1791	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1523	undef $SIG_EV{$signal};	1792	undef $SIG_EV{$signal};
1524	};	1793	};
1525		1794
1526	# can't do signal processing without introducing races in pure perl,	1795	# can't do signal processing without introducing races in pure perl,
1527	# so limit the signal latency.	1796	# so limit the signal latency.
1528	_sig_add;	1797	_sig_add;
1529	}
1530		1798
1531	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1799	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1800	}
1532	};	1801	;
1533		1802
1534	*AnyEvent::Base::signal::DESTROY = sub {	1803	*AnyEvent::Base::signal::DESTROY = sub {
1535	my ($signal, $cb) = @{$_[0]};	1804	my ($signal, $cb) = @{$_[0]};
1536		1805
1537	_sig_del;	1806	_sig_del;
…		…
1544	# print weird messages, or just unconditionally exit	1813	# print weird messages, or just unconditionally exit
1545	# instead of getting the default action.	1814	# instead of getting the default action.
1546	undef $SIG{$signal}	1815	undef $SIG{$signal}
1547	unless keys %{ $SIG_CB{$signal} };	1816	unless keys %{ $SIG_CB{$signal} };
1548	};	1817	};
		1818
		1819	*_signal_exec = sub {
		1820	$HAVE_ASYNC_INTERRUPT
		1821	? $SIGPIPE_R->drain
		1822	: sysread $SIGPIPE_R, (my $dummy), 9;
		1823
		1824	while (%SIG_EV) {
		1825	for (keys %SIG_EV) {
		1826	delete $SIG_EV{$_};
		1827	&$_ for values %{ $SIG_CB{$_} || {} };
		1828	}
		1829	}
		1830	};
1549	};	1831	};
1550	die if $@;	1832	die if $@;
		1833
1551	&signal	1834	&signal
1552	}	1835	}
1553		1836
1554	# default implementation for ->child	1837	# default implementation for ->child
1555		1838
1556	our %PID_CB;	1839	our %PID_CB;
1557	our $CHLD_W;	1840	our $CHLD_W;
1558	our $CHLD_DELAY_W;	1841	our $CHLD_DELAY_W;
1559	our $WNOHANG;
1560		1842
		1843	# used by many Impl's
1561	sub _emit_childstatus($$) {	1844	sub _emit_childstatus($$) {
1562	my (undef, $rpid, $rstatus) = @_;	1845	my (undef, $rpid, $rstatus) = @_;
1563		1846
1564	$_->($rpid, $rstatus)	1847	$_->($rpid, $rstatus)
1565	for values %{ $PID_CB{$rpid} || {} },	1848	for values %{ $PID_CB{$rpid} || {} },
1566	values %{ $PID_CB{0} || {} };	1849	values %{ $PID_CB{0} || {} };
1567	}	1850	}
1568		1851
1569	sub _sigchld {
1570	my $pid;
1571
1572	AnyEvent->_emit_childstatus ($pid, $?)
1573	while ($pid = waitpid -1, $WNOHANG) > 0;
1574	}
1575
1576	sub child {	1852	sub child {
		1853	eval q{ # poor man's autoloading {}
		1854	*_sigchld = sub {
		1855	my $pid;
		1856
		1857	AnyEvent->_emit_childstatus ($pid, $?)
		1858	while ($pid = waitpid -1, WNOHANG) > 0;
		1859	};
		1860
		1861	*child = sub {
1577	my (undef, %arg) = @_;	1862	my (undef, %arg) = @_;
1578		1863
1579	defined (my $pid = $arg{pid} + 0)	1864	my $pid = $arg{pid};
1580	or Carp::croak "required option 'pid' is missing";	1865	my $cb = $arg{cb};
1581		1866
1582	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1867	$PID_CB{$pid}{$cb+0} = $cb;
1583		1868
1584	# WNOHANG is almost cetrainly 1 everywhere
1585	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1586	? 1
1587	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1588
1589	unless ($CHLD_W) {	1869	unless ($CHLD_W) {
1590	$CHLD_W = AE::signal CHLD => \&_sigchld;	1870	$CHLD_W = AE::signal CHLD => \&_sigchld;
1591	# child could be a zombie already, so make at least one round	1871	# child could be a zombie already, so make at least one round
1592	&_sigchld;	1872	&_sigchld;
1593	}	1873	}
1594		1874
1595	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1875	bless [$pid, $cb+0], "AnyEvent::Base::child"
1596	}	1876	};
1597		1877
1598	sub AnyEvent::Base::child::DESTROY {	1878	*AnyEvent::Base::child::DESTROY = sub {
1599	my ($pid, $cb) = @{$_[0]};	1879	my ($pid, $icb) = @{$_[0]};
1600		1880
1601	delete $PID_CB{$pid}{$cb};	1881	delete $PID_CB{$pid}{$icb};
1602	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1882	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1603		1883
1604	undef $CHLD_W unless keys %PID_CB;	1884	undef $CHLD_W unless keys %PID_CB;
		1885	};
		1886	};
		1887	die if $@;
		1888
		1889	&child
1605	}	1890	}
1606		1891
1607	# idle emulation is done by simply using a timer, regardless	1892	# idle emulation is done by simply using a timer, regardless
1608	# of whether the process is idle or not, and not letting	1893	# of whether the process is idle or not, and not letting
1609	# the callback use more than 50% of the time.	1894	# the callback use more than 50% of the time.
1610	sub idle {	1895	sub idle {
		1896	eval q{ # poor man's autoloading {}
		1897	*idle = sub {
1611	my (undef, %arg) = @_;	1898	my (undef, %arg) = @_;
1612		1899
1613	my ($cb, $w, $rcb) = $arg{cb};	1900	my ($cb, $w, $rcb) = $arg{cb};
1614		1901
1615	$rcb = sub {	1902	$rcb = sub {
1616	if ($cb) {	1903	if ($cb) {
1617	$w = _time;	1904	$w = AE::time;
1618	&$cb;	1905	&$cb;
1619	$w = _time - $w;	1906	$w = AE::time - $w;
1620		1907
1621	# never use more then 50% of the time for the idle watcher,	1908	# never use more then 50% of the time for the idle watcher,
1622	# within some limits	1909	# within some limits
1623	$w = 0.0001 if $w < 0.0001;	1910	$w = 0.0001 if $w < 0.0001;
1624	$w = 5 if $w > 5;	1911	$w = 5 if $w > 5;
1625		1912
1626	$w = AE::timer $w, 0, $rcb;	1913	$w = AE::timer $w, 0, $rcb;
1627	} else {	1914	} else {
1628	# clean up...	1915	# clean up...
1629	undef $w;	1916	undef $w;
1630	undef $rcb;	1917	undef $rcb;
		1918	}
		1919	};
		1920
		1921	$w = AE::timer 0.05, 0, $rcb;
		1922
		1923	bless \\$cb, "AnyEvent::Base::idle"
1631	}	1924	};
		1925
		1926	*AnyEvent::Base::idle::DESTROY = sub {
		1927	undef $${$_[0]};
		1928	};
1632	};	1929	};
		1930	die if $@;
1633		1931
1634	$w = AE::timer 0.05, 0, $rcb;	1932	&idle
1635
1636	bless \\$cb, "AnyEvent::Base::idle"
1637	}
1638
1639	sub AnyEvent::Base::idle::DESTROY {
1640	undef $${$_[0]};
1641	}	1933	}
1642		1934
1643	package AnyEvent::CondVar;	1935	package AnyEvent::CondVar;
1644		1936
1645	our @ISA = AnyEvent::CondVar::Base::;	1937	our @ISA = AnyEvent::CondVar::Base::;
		1938
		1939	# only to be used for subclassing
		1940	sub new {
		1941	my $class = shift;
		1942	bless AnyEvent->condvar (@_), $class
		1943	}
1646		1944
1647	package AnyEvent::CondVar::Base;	1945	package AnyEvent::CondVar::Base;
1648		1946
1649	#use overload	1947	#use overload
1650	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1948	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
…		…
1660		1958
1661	sub _send {	1959	sub _send {
1662	# nop	1960	# nop
1663	}	1961	}
1664		1962
		1963	sub _wait {
		1964	AnyEvent->_poll until $_[0]{_ae_sent};
		1965	}
		1966
1665	sub send {	1967	sub send {
1666	my $cv = shift;	1968	my $cv = shift;
1667	$cv->{_ae_sent} = [@_];	1969	$cv->{_ae_sent} = [@_];
1668	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};	1970	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1669	$cv->_send;	1971	$cv->_send;
…		…
1676		1978
1677	sub ready {	1979	sub ready {
1678	$_[0]{_ae_sent}	1980	$_[0]{_ae_sent}
1679	}	1981	}
1680		1982
1681	sub _wait {
1682	$WAITING
1683	and !$_[0]{_ae_sent}
1684	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1685
1686	local $WAITING = 1;
1687	AnyEvent->one_event while !$_[0]{_ae_sent};
1688	}
1689
1690	sub recv {	1983	sub recv {
		1984	unless ($_[0]{_ae_sent}) {
		1985	$WAITING
		1986	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1987
		1988	local $WAITING = 1;
1691	$_[0]->_wait;	1989	$_[0]->_wait;
		1990	}
1692		1991
1693	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1992	$_[0]{_ae_croak}
1694	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1993	and Carp::croak $_[0]{_ae_croak};
		1994
		1995	wantarray
		1996	? @{ $_[0]{_ae_sent} }
		1997	: $_[0]{_ae_sent}[0]
1695	}	1998	}
1696		1999
1697	sub cb {	2000	sub cb {
1698	my $cv = shift;	2001	my $cv = shift;
1699		2002
…		…
1715	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	2018	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1716	}	2019	}
1717		2020
1718	# undocumented/compatibility with pre-3.4	2021	# undocumented/compatibility with pre-3.4
1719	*broadcast = \&send;	2022	*broadcast = \&send;
1720	*wait = \&_wait;	2023	*wait = \&recv;
1721		2024
1722	=head1 ERROR AND EXCEPTION HANDLING	2025	=head1 ERROR AND EXCEPTION HANDLING
1723		2026
1724	In general, AnyEvent does not do any error handling - it relies on the	2027	In general, AnyEvent does not do any error handling - it relies on the
1725	caller to do that if required. The L<AnyEvent::Strict> module (see also	2028	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1737	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and	2040	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1738	so on.	2041	so on.
1739		2042
1740	=head1 ENVIRONMENT VARIABLES	2043	=head1 ENVIRONMENT VARIABLES
1741		2044
1742	The following environment variables are used by this module or its	2045	AnyEvent supports a number of environment variables that tune the
1743	submodules.	2046	runtime behaviour. They are usually evaluated when AnyEvent is
		2047	loaded, initialised, or a submodule that uses them is loaded. Many of
		2048	them also cause AnyEvent to load additional modules - for example,
		2049	C<PERL_ANYEVENT_DEBUG_WRAP> causes the L<AnyEvent::Debug> module to be
		2050	loaded.
1744		2051
1745	Note that AnyEvent will remove I<all> environment variables starting with	2052	All the environment variables documented here start with
1746	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is	2053	C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
1747	enabled.	2054	namespace. Other modules are encouraged (but by no means required) to use
		2055	C<PERL_ANYEVENT_SUBMODULE> if they have registered the AnyEvent::Submodule
		2056	namespace on CPAN, for any submodule. For example, L<AnyEvent::HTTP> could
		2057	be expected to use C<PERL_ANYEVENT_HTTP_PROXY> (it should not access env
		2058	variables starting with C<AE_>, see below).
		2059
		2060	All variables can also be set via the C<AE_> prefix, that is, instead
		2061	of setting C<PERL_ANYEVENT_VERBOSE> you can also set C<AE_VERBOSE>. In
		2062	case there is a clash btween anyevent and another program that uses
		2063	C<AE_something> you can set the corresponding C<PERL_ANYEVENT_something>
		2064	variable to the empty string, as those variables take precedence.
		2065
		2066	When AnyEvent is first loaded, it copies all C<AE_xxx> env variables
		2067	to their C<PERL_ANYEVENT_xxx> counterpart unless that variable already
		2068	exists. If taint mode is on, then AnyEvent will remove I<all> environment
		2069	variables starting with C<PERL_ANYEVENT_> from C<%ENV> (or replace them
		2070	with C<undef> or the empty string, if the corresaponding C<AE_> variable
		2071	is set).
		2072
		2073	The exact algorithm is currently:
		2074
		2075	1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
		2076	2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
		2077	3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
		2078
		2079	This ensures that child processes will not see the C<AE_> variables.
		2080
		2081	The following environment variables are currently known to AnyEvent:
1748		2082
1749	=over 4	2083	=over 4
1750		2084
1751	=item C<PERL_ANYEVENT_VERBOSE>	2085	=item C<PERL_ANYEVENT_VERBOSE>
1752		2086
1753	By default, AnyEvent will be completely silent except in fatal	2087	By default, AnyEvent will log messages with loglevel C<4> (C<error>) or
1754	conditions. You can set this environment variable to make AnyEvent more	2088	higher (see L<AnyEvent::Log>). You can set this environment variable to a
1755	talkative.	2089	numerical loglevel to make AnyEvent more (or less) talkative.
1756		2090
		2091	If you want to do more than just set the global logging level
		2092	you should have a look at C<PERL_ANYEVENT_LOG>, which allows much more
		2093	complex specifications.
		2094
		2095	When set to C<0> (C<off>), then no messages whatsoever will be logged with
		2096	everything else at defaults.
		2097
1757	When set to C<1> or higher, causes AnyEvent to warn about unexpected	2098	When set to C<5> or higher (C<warn>), AnyEvent warns about unexpected
1758	conditions, such as not being able to load the event model specified by	2099	conditions, such as not being able to load the event model specified by
1759	C<PERL_ANYEVENT_MODEL>.	2100	C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an exception - this
		2101	is the minimum recommended level for use during development.
1760		2102
1761	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	2103	When set to C<7> or higher (info), AnyEvent reports which event model it
1762	model it chooses.	2104	chooses.
1763		2105
1764	When set to C<8> or higher, then AnyEvent will report extra information on	2106	When set to C<8> or higher (debug), then AnyEvent will report extra
1765	which optional modules it loads and how it implements certain features.	2107	information on which optional modules it loads and how it implements
		2108	certain features.
		2109
		2110	=item C<PERL_ANYEVENT_LOG>
		2111
		2112	Accepts rather complex logging specifications. For example, you could log
		2113	all C<debug> messages of some module to stderr, warnings and above to
		2114	stderr, and errors and above to syslog, with:
		2115
		2116	PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
		2117
		2118	For the rather extensive details, see L<AnyEvent::Log>.
		2119
		2120	This variable is evaluated when AnyEvent (or L<AnyEvent::Log>) is loaded,
		2121	so will take effect even before AnyEvent has initialised itself.
		2122
		2123	Note that specifying this environment variable causes the L<AnyEvent::Log>
		2124	module to be loaded, while C<PERL_ANYEVENT_VERBOSE> does not, so only
		2125	using the latter saves a few hundred kB of memory unless a module
		2126	explicitly needs the extra features of AnyEvent::Log.
1766		2127
1767	=item C<PERL_ANYEVENT_STRICT>	2128	=item C<PERL_ANYEVENT_STRICT>
1768		2129
1769	AnyEvent does not do much argument checking by default, as thorough	2130	AnyEvent does not do much argument checking by default, as thorough
1770	argument checking is very costly. Setting this variable to a true value	2131	argument checking is very costly. Setting this variable to a true value
…		…
1772	check the arguments passed to most method calls. If it finds any problems,	2133	check the arguments passed to most method calls. If it finds any problems,
1773	it will croak.	2134	it will croak.
1774		2135
1775	In other words, enables "strict" mode.	2136	In other words, enables "strict" mode.
1776		2137
1777	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	2138	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1778	>>, it is definitely recommended to keep it off in production. Keeping	2139	>>, it is definitely recommended to keep it off in production. Keeping
1779	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	2140	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1780	can be very useful, however.	2141	can be very useful, however.
1781		2142
		2143	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		2144
		2145	If this env variable is nonempty, then its contents will be interpreted by
		2146	C<AnyEvent::Socket::parse_hostport> and C<AnyEvent::Debug::shell> (after
		2147	replacing every occurance of C<$$> by the process pid). The shell object
		2148	is saved in C<$AnyEvent::Debug::SHELL>.
		2149
		2150	This happens when the first watcher is created.
		2151
		2152	For example, to bind a debug shell on a unix domain socket in
		2153	F<< /tmp/debug<pid>.sock >>, you could use this:
		2154
		2155	PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
		2156	# connect with e.g.: socat readline /tmp/debug123.sock
		2157
		2158	Or to bind to tcp port 4545 on localhost:
		2159
		2160	PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog
		2161	# connect with e.g.: telnet localhost 4545
		2162
		2163	Note that creating sockets in F</tmp> or on localhost is very unsafe on
		2164	multiuser systems.
		2165
		2166	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		2167
		2168	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		2169	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
		2170
1782	=item C<PERL_ANYEVENT_MODEL>	2171	=item C<PERL_ANYEVENT_MODEL>
1783		2172
1784	This can be used to specify the event model to be used by AnyEvent, before	2173	This can be used to specify the event model to be used by AnyEvent, before
1785	auto detection and -probing kicks in. It must be a string consisting	2174	auto detection and -probing kicks in.
1786	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	2175
		2176	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		2177	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1787	and the resulting module name is loaded and if the load was successful,	2178	resulting module name is loaded and - if the load was successful - used as
1788	used as event model. If it fails to load AnyEvent will proceed with	2179	event model backend. If it fails to load then AnyEvent will proceed with
1789	auto detection and -probing.	2180	auto detection and -probing.
1790		2181
1791	This functionality might change in future versions.	2182	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		2183	nothing gets prepended and the module name is used as-is (hint: C<::> at
		2184	the end of a string designates a module name and quotes it appropriately).
1792		2185
1793	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	2186	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1794	could start your program like this:	2187	could start your program like this:
1795		2188
1796	PERL_ANYEVENT_MODEL=Perl perl ...	2189	PERL_ANYEVENT_MODEL=Perl perl ...
		2190
		2191	=item C<PERL_ANYEVENT_IO_MODEL>
		2192
		2193	The current file I/O model - see L<AnyEvent::IO> for more info.
		2194
		2195	At the moment, only C<Perl> (small, pure-perl, synchronous) and
		2196	C<IOAIO> (truly asynchronous) are supported. The default is C<IOAIO> if
		2197	L<AnyEvent::AIO> can be loaded, otherwise it is C<Perl>.
1797		2198
1798	=item C<PERL_ANYEVENT_PROTOCOLS>	2199	=item C<PERL_ANYEVENT_PROTOCOLS>
1799		2200
1800	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences	2201	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1801	for IPv4 or IPv6. The default is unspecified (and might change, or be the result	2202	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
…		…
1814	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>	2215	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1815	- only support IPv4, never try to resolve or contact IPv6	2216	- only support IPv4, never try to resolve or contact IPv6
1816	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or	2217	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1817	IPv6, but prefer IPv6 over IPv4.	2218	IPv6, but prefer IPv6 over IPv4.
1818		2219
		2220	=item C<PERL_ANYEVENT_HOSTS>
		2221
		2222	This variable, if specified, overrides the F</etc/hosts> file used by
		2223	L<AnyEvent::Socket>C<::resolve_sockaddr>, i.e. hosts aliases will be read
		2224	from that file instead.
		2225
1819	=item C<PERL_ANYEVENT_EDNS0>	2226	=item C<PERL_ANYEVENT_EDNS0>
1820		2227
1821	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension	2228	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension for
1822	for DNS. This extension is generally useful to reduce DNS traffic, but	2229	DNS. This extension is generally useful to reduce DNS traffic, especially
1823	some (broken) firewalls drop such DNS packets, which is why it is off by	2230	when DNSSEC is involved, but some (broken) firewalls drop such DNS
1824	default.	2231	packets, which is why it is off by default.
1825		2232
1826	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce	2233	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1827	EDNS0 in its DNS requests.	2234	EDNS0 in its DNS requests.
1828		2235
1829	=item C<PERL_ANYEVENT_MAX_FORKS>	2236	=item C<PERL_ANYEVENT_MAX_FORKS>
…		…
1835		2242
1836	The default value for the C<max_outstanding> parameter for the default DNS	2243	The default value for the C<max_outstanding> parameter for the default DNS
1837	resolver - this is the maximum number of parallel DNS requests that are	2244	resolver - this is the maximum number of parallel DNS requests that are
1838	sent to the DNS server.	2245	sent to the DNS server.
1839		2246
		2247	=item C<PERL_ANYEVENT_MAX_SIGNAL_LATENCY>
		2248
		2249	Perl has inherently racy signal handling (you can basically choose between
		2250	losing signals and memory corruption) - pure perl event loops (including
		2251	C<AnyEvent::Loop>, when C<Async::Interrupt> isn't available) therefore
		2252	have to poll regularly to avoid losing signals.
		2253
		2254	Some event loops are racy, but don't poll regularly, and some event loops
		2255	are written in C but are still racy. For those event loops, AnyEvent
		2256	installs a timer that regularly wakes up the event loop.
		2257
		2258	By default, the interval for this timer is C<10> seconds, but you can
		2259	override this delay with this environment variable (or by setting
		2260	the C<$AnyEvent::MAX_SIGNAL_LATENCY> variable before creating signal
		2261	watchers).
		2262
		2263	Lower values increase CPU (and energy) usage, higher values can introduce
		2264	long delays when reaping children or waiting for signals.
		2265
		2266	The L<AnyEvent::Async> module, if available, will be used to avoid this
		2267	polling (with most event loops).
		2268
1840	=item C<PERL_ANYEVENT_RESOLV_CONF>	2269	=item C<PERL_ANYEVENT_RESOLV_CONF>
1841		2270
1842	The file to use instead of F</etc/resolv.conf> (or OS-specific	2271	The absolute path to a F<resolv.conf>-style file to use instead of
1843	configuration) in the default resolver. When set to the empty string, no	2272	F</etc/resolv.conf> (or the OS-specific configuration) in the default
1844	default config will be used.	2273	resolver, or the empty string to select the default configuration.
1845		2274
1846	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.	2275	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1847		2276
1848	When neither C<ca_file> nor C<ca_path> was specified during	2277	When neither C<ca_file> nor C<ca_path> was specified during
1849	L<AnyEvent::TLS> context creation, and either of these environment	2278	L<AnyEvent::TLS> context creation, and either of these environment
1850	variables exist, they will be used to specify CA certificate locations	2279	variables are nonempty, they will be used to specify CA certificate
1851	instead of a system-dependent default.	2280	locations instead of a system-dependent default.
1852		2281
1853	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>	2282	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1854		2283
1855	When these are set to C<1>, then the respective modules are not	2284	When these are set to C<1>, then the respective modules are not
1856	loaded. Mostly good for testing AnyEvent itself.	2285	loaded. Mostly good for testing AnyEvent itself.
…		…
2004		2433
2005	The actual code goes further and collects all errors (C<die>s, exceptions)	2434	The actual code goes further and collects all errors (C<die>s, exceptions)
2006	that occurred during request processing. The C<result> method detects	2435	that occurred during request processing. The C<result> method detects
2007	whether an exception as thrown (it is stored inside the $txn object)	2436	whether an exception as thrown (it is stored inside the $txn object)
2008	and just throws the exception, which means connection errors and other	2437	and just throws the exception, which means connection errors and other
2009	problems get reported tot he code that tries to use the result, not in a	2438	problems get reported to the code that tries to use the result, not in a
2010	random callback.	2439	random callback.
2011		2440
2012	All of this enables the following usage styles:	2441	All of this enables the following usage styles:
2013		2442
2014	1. Blocking:	2443	1. Blocking:
…		…
2188	(even when used without AnyEvent), but most event loops have acceptable	2617	(even when used without AnyEvent), but most event loops have acceptable
2189	performance with or without AnyEvent.	2618	performance with or without AnyEvent.
2190		2619
2191	=item * The overhead AnyEvent adds is usually much smaller than the overhead of	2620	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
2192	the actual event loop, only with extremely fast event loops such as EV	2621	the actual event loop, only with extremely fast event loops such as EV
2193	adds AnyEvent significant overhead.	2622	does AnyEvent add significant overhead.
2194		2623
2195	=item * You should avoid POE like the plague if you want performance or	2624	=item * You should avoid POE like the plague if you want performance or
2196	reasonable memory usage.	2625	reasonable memory usage.
2197		2626
2198	=back	2627	=back
…		…
2428	unless defined $SIG{PIPE};	2857	unless defined $SIG{PIPE};
2429		2858
2430	=head1 RECOMMENDED/OPTIONAL MODULES	2859	=head1 RECOMMENDED/OPTIONAL MODULES
2431		2860
2432	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2861	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2433	it's built-in modules) are required to use it.	2862	its built-in modules) are required to use it.
2434		2863
2435	That does not mean that AnyEvent won't take advantage of some additional	2864	That does not mean that AnyEvent won't take advantage of some additional
2436	modules if they are installed.	2865	modules if they are installed.
2437		2866
2438	This section epxlains which additional modules will be used, and how they	2867	This section explains which additional modules will be used, and how they
2439	affect AnyEvent's operetion.	2868	affect AnyEvent's operation.
2440		2869
2441	=over 4	2870	=over 4
2442		2871
2443	=item L<Async::Interrupt>	2872	=item L<Async::Interrupt>
2444		2873
…		…
2449	catch the signals) with some delay (default is 10 seconds, look for	2878	catch the signals) with some delay (default is 10 seconds, look for
2450	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2879	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2451		2880
2452	If this module is available, then it will be used to implement signal	2881	If this module is available, then it will be used to implement signal
2453	catching, which means that signals will not be delayed, and the event loop	2882	catching, which means that signals will not be delayed, and the event loop
2454	will not be interrupted regularly, which is more efficient (And good for	2883	will not be interrupted regularly, which is more efficient (and good for
2455	battery life on laptops).	2884	battery life on laptops).
2456		2885
2457	This affects not just the pure-perl event loop, but also other event loops	2886	This affects not just the pure-perl event loop, but also other event loops
2458	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2887	that have no signal handling on their own (e.g. Glib, Tk, Qt).
2459		2888
…		…
2471	automatic timer adjustments even when no monotonic clock is available,	2900	automatic timer adjustments even when no monotonic clock is available,
2472	can take avdantage of advanced kernel interfaces such as C<epoll> and	2901	can take avdantage of advanced kernel interfaces such as C<epoll> and
2473	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2902	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2474	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2903	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2475		2904
		2905	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2906	then this module will do nothing for you.
		2907
2476	=item L<Guard>	2908	=item L<Guard>
2477		2909
2478	The guard module, when used, will be used to implement	2910	The guard module, when used, will be used to implement
2479	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2911	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2480	lot less memory), but otherwise doesn't affect guard operation much. It is	2912	lot less memory), but otherwise doesn't affect guard operation much. It is
2481	purely used for performance.	2913	purely used for performance.
2482		2914
2483	=item L<JSON> and L<JSON::XS>	2915	=item L<JSON> and L<JSON::XS>
2484		2916
2485	One of these modules is required when you want to read or write JSON data	2917	One of these modules is required when you want to read or write JSON data
2486	via L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2918	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2487	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.	2919	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2488
2489	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2490	installed.
2491		2920
2492	=item L<Net::SSLeay>	2921	=item L<Net::SSLeay>
2493		2922
2494	Implementing TLS/SSL in Perl is certainly interesting, but not very	2923	Implementing TLS/SSL in Perl is certainly interesting, but not very
2495	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2924	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2496	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2925	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2497		2926
2498	=item L<Time::HiRes>	2927	=item L<Time::HiRes>
2499		2928
2500	This module is part of perl since release 5.008. It will be used when the	2929	This module is part of perl since release 5.008. It will be used when the
2501	chosen event library does not come with a timing source on it's own. The	2930	chosen event library does not come with a timing source of its own. The
2502	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2931	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2503	try to use a monotonic clock for timing stability.	2932	try to use a monotonic clock for timing stability.
2504		2933
		2934	=item L<AnyEvent::AIO> (and L<IO::AIO>)
		2935
		2936	The default implementation of L<AnyEvent::IO> is to do I/O synchronously,
		2937	stopping programs while they access the disk, which is fine for a lot of
		2938	programs.
		2939
		2940	Installing AnyEvent::AIO (and its IO::AIO dependency) makes it switch to
		2941	a true asynchronous implementation, so event processing can continue even
		2942	while waiting for disk I/O.
		2943
2505	=back	2944	=back
2506		2945
2507		2946
2508	=head1 FORK	2947	=head1 FORK
2509		2948
2510	Most event libraries are not fork-safe. The ones who are usually are	2949	Most event libraries are not fork-safe. The ones who are usually are
2511	because they rely on inefficient but fork-safe C<select> or C<poll>	2950	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2512	calls. Only L<EV> is fully fork-aware.	2951	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2952	are usually badly thought-out hacks that are incompatible with fork in
		2953	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2954	continue event-processing in both parent and child (or both, if you know
		2955	what you are doing).
		2956
		2957	This means that, in general, you cannot fork and do event processing in
		2958	the child if the event library was initialised before the fork (which
		2959	usually happens when the first AnyEvent watcher is created, or the library
		2960	is loaded).
2513		2961
2514	If you have to fork, you must either do so I<before> creating your first	2962	If you have to fork, you must either do so I<before> creating your first
2515	watcher OR you must not use AnyEvent at all in the child OR you must do	2963	watcher OR you must not use AnyEvent at all in the child OR you must do
2516	something completely out of the scope of AnyEvent.	2964	something completely out of the scope of AnyEvent.
		2965
		2966	The problem of doing event processing in the parent I<and> the child
		2967	is much more complicated: even for backends that I<are> fork-aware or
		2968	fork-safe, their behaviour is not usually what you want: fork clones all
		2969	watchers, that means all timers, I/O watchers etc. are active in both
		2970	parent and child, which is almost never what you want. USing C<exec>
		2971	to start worker children from some kind of manage rprocess is usually
		2972	preferred, because it is much easier and cleaner, at the expense of having
		2973	to have another binary.
2517		2974
2518		2975
2519	=head1 SECURITY CONSIDERATIONS	2976	=head1 SECURITY CONSIDERATIONS
2520		2977
2521	AnyEvent can be forced to load any event model via	2978	AnyEvent can be forced to load any event model via
…		…
2551	pronounced).	3008	pronounced).
2552		3009
2553		3010
2554	=head1 SEE ALSO	3011	=head1 SEE ALSO
2555		3012
2556	Utility functions: L<AnyEvent::Util>.	3013	Tutorial/Introduction: L<AnyEvent::Intro>.
2557		3014
2558	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	3015	FAQ: L<AnyEvent::FAQ>.
2559	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	3016
		3017	Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
		3018	(simply logging).
		3019
		3020	Development/Debugging: L<AnyEvent::Strict> (stricter checking),
		3021	L<AnyEvent::Debug> (interactive shell, watcher tracing).
		3022
		3023	Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
		3024	L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
		3025	L<Qt>, L<POE>, L<FLTK>.
2560		3026
2561	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	3027	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2562	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	3028	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2563	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	3029	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2564	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.	3030	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
		3031	L<AnyEvent::Impl::FLTK>.
2565		3032
2566	Non-blocking file handles, sockets, TCP clients and	3033	Non-blocking handles, pipes, stream sockets, TCP clients and
2567	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	3034	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2568		3035
		3036	Asynchronous File I/O: L<AnyEvent::IO>.
		3037
2569	Asynchronous DNS: L<AnyEvent::DNS>.	3038	Asynchronous DNS: L<AnyEvent::DNS>.
2570		3039
2571	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	3040	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2572	L<Coro::Event>,
2573		3041
2574	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	3042	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2575	L<AnyEvent::HTTP>.	3043	L<AnyEvent::HTTP>.
2576		3044
2577		3045
2578	=head1 AUTHOR	3046	=head1 AUTHOR
2579		3047
2580	Marc Lehmann <schmorp@schmorp.de>	3048	Marc Lehmann <schmorp@schmorp.de>
2581	http://home.schmorp.de/	3049	http://anyevent.schmorp.de
2582		3050
2583	=cut	3051	=cut
2584		3052
2585	1	3053	1
2586		3054

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