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Revision 1.303 by root, Sat Dec 5 02:52:03 2009 UTC vs.
Revision 1.358 by root, Sat Aug 13 02:35:32 2011 UTC

…		…
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 {
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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
…		…
425	=head3 Signal Races, Delays and Workarounds	429	=head3 Signal Races, Delays and Workarounds
426		430
427	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 attaching
428	callbacks to signals in a generic way, which is a pity, as you cannot	432	callbacks to signals in a generic way, which is a pity, as you cannot
429	do race-free signal handling in perl, requiring C libraries for	433	do race-free signal handling in perl, requiring C libraries for
430	this. AnyEvent will try to do it's best, which means in some cases,	434	this. AnyEvent will try to do its best, which means in some cases,
431	signals will be delayed. The maximum time a signal might be delayed is	435	signals will be delayed. The maximum time a signal might be delayed is
432	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This	436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
433	variable can be changed only before the first signal watcher is created,	437	variable can be changed only before the first signal watcher is created,
434	and should be left alone otherwise. This variable determines how often	438	and should be left alone otherwise. This variable determines how often
435	AnyEvent polls for signals (in case a wake-up was missed). Higher values	439	AnyEvent polls for signals (in case a wake-up was missed). Higher values
…		…
437	saving.	441	saving.
438		442
439	All these problems can be avoided by installing the optional	443	All these problems can be avoided by installing the optional
440	L<Async::Interrupt> module, which works with most event loops. It will not	444	L<Async::Interrupt> module, which works with most event loops. It will not
441	work with inherently broken event loops such as L<Event> or L<Event::Lib>	445	work with inherently broken event loops such as L<Event> or L<Event::Lib>
442	(and not with L<POE> currently, as POE does it's own workaround with	446	(and not with L<POE> currently, as POE does its own workaround with
443	one-second latency). For those, you just have to suffer the delays.	447	one-second latency). For those, you just have to suffer the delays.
444		448
445	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
446		450
447	$w = AnyEvent->child (pid => <process id>, cb => <callback>);	451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
448		452
449	You can also watch on a child process exit and catch its exit status.	453	You can also watch for a child process exit and catch its exit status.
450		454
451	The child process is specified by the C<pid> argument (one some backends,	455	The child process is specified by the C<pid> argument (on some backends,
452	using C<0> watches for any child process exit, on others this will	456	using C<0> watches for any child process exit, on others this will
453	croak). The watcher will be triggered only when the child process has	457	croak). The watcher will be triggered only when the child process has
454	finished and an exit status is available, not on any trace events	458	finished and an exit status is available, not on any trace events
455	(stopped/continued).	459	(stopped/continued).
456		460
…		…
478	thing in an AnyEvent program, you I<have> to create at least one	482	thing in an AnyEvent program, you I<have> to create at least one
479	watcher before you C<fork> the child (alternatively, you can call	483	watcher before you C<fork> the child (alternatively, you can call
480	C<AnyEvent::detect>).	484	C<AnyEvent::detect>).
481		485
482	As most event loops do not support waiting for child events, they will be	486	As most event loops do not support waiting for child events, they will be
483	emulated by AnyEvent in most cases, in which the latency and race problems	487	emulated by AnyEvent in most cases, in which case the latency and race
484	mentioned in the description of signal watchers apply.	488	problems mentioned in the description of signal watchers apply.
485		489
486	Example: fork a process and wait for it	490	Example: fork a process and wait for it
487		491
488	my $done = AnyEvent->condvar;	492	my $done = AnyEvent->condvar;
489		493
…		…
503		507
504	=head2 IDLE WATCHERS	508	=head2 IDLE WATCHERS
505		509
506	$w = AnyEvent->idle (cb => <callback>);	510	$w = AnyEvent->idle (cb => <callback>);
507		511
508	Sometimes there is a need to do something, but it is not so important	512	This will repeatedly invoke the callback after the process becomes idle,
509	to do it instantly, but only when there is nothing better to do. This	513	until either the watcher is destroyed or new events have been detected.
510	"nothing better to do" is usually defined to be "no other events need
511	attention by the event loop".
512		514
513	Idle watchers ideally get invoked when the event loop has nothing	515	Idle watchers are useful when there is a need to do something, but it
514	better to do, just before it would block the process to wait for new	516	is not so important (or wise) to do it instantly. The callback will be
515	events. Instead of blocking, the idle watcher is invoked.	517	invoked only when there is "nothing better to do", which is usually
		518	defined as "all outstanding events have been handled and no new events
		519	have been detected". That means that idle watchers ideally get invoked
		520	when the event loop has just polled for new events but none have been
		521	detected. Instead of blocking to wait for more events, the idle watchers
		522	will be invoked.
516		523
517	Most event loops unfortunately do not really support idle watchers (only	524	Unfortunately, most event loops do not really support idle watchers (only
518	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	525	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
519	will simply call the callback "from time to time".	526	will simply call the callback "from time to time".
520		527
521	Example: read lines from STDIN, but only process them when the	528	Example: read lines from STDIN, but only process them when the
522	program is otherwise idle:	529	program is otherwise idle:
…		…
550	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
551		558
552	AnyEvent is slightly different: it expects somebody else to run the event	559	AnyEvent is slightly different: it expects somebody else to run the event
553	loop and will only block when necessary (usually when told by the user).	560	loop and will only block when necessary (usually when told by the user).
554		561
555	The instrument to do that is called a "condition variable", so called	562	The tool to do that is called a "condition variable", so called because
556	because they represent a condition that must become true.	563	they represent a condition that must become true.
557		564
558	Now is probably a good time to look at the examples further below.	565	Now is probably a good time to look at the examples further below.
559		566
560	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
561	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
…		…
566	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
567	by calling the C<send> method (or calling the condition variable as if it	574	by calling the C<send> method (or calling the condition variable as if it
568	were a callback, read about the caveats in the description for the C<<	575	were a callback, read about the caveats in the description for the C<<
569	->send >> method).	576	->send >> method).
570		577
571	Condition variables are similar to callbacks, except that you can	578	Since condition variables are the most complex part of the AnyEvent API, here are
572	optionally wait for them. They can also be called merge points - points	579	some different mental models of what they are - pick the ones you can connect to:
573	in time where multiple outstanding events have been processed. And yet	580
574	another way to call them is transactions - each condition variable can be	581	=over 4
575	used to represent a transaction, which finishes at some point and delivers	582
576	a result. And yet some people know them as "futures" - a promise to	583	=item * Condition variables are like callbacks - you can call them (and pass them instead
577	compute/deliver something that you can wait for.	584	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		585
		586	=item * Condition variables are signals - one side can emit or send them,
		587	the other side can wait for them, or install a handler that is called when
		588	the signal fires.
		589
		590	=item * Condition variables are like "Merge Points" - points in your program
		591	where you merge multiple independent results/control flows into one.
		592
		593	=item * Condition variables represent a transaction - functions that start
		594	some kind of transaction can return them, leaving the caller the choice
		595	between waiting in a blocking fashion, or setting a callback.
		596
		597	=item * Condition variables represent future values, or promises to deliver
		598	some result, long before the result is available.
		599
		600	=back
578		601
579	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
580	for example, if you write a module that does asynchronous http requests,	603	for example, if you write a module that does asynchronous http requests,
581	then a condition variable would be the ideal candidate to signal the	604	then a condition variable would be the ideal candidate to signal the
582	availability of results. The user can either act when the callback is	605	availability of results. The user can either act when the callback is
…		…
595		618
596	Condition variables are represented by hash refs in perl, and the keys	619	Condition variables are represented by hash refs in perl, and the keys
597	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing	620	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
598	easy (it is often useful to build your own transaction class on top of	621	easy (it is often useful to build your own transaction class on top of
599	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call	622	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
600	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
601		624
602	There are two "sides" to a condition variable - the "producer side" which	625	There are two "sides" to a condition variable - the "producer side" which
603	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
604	for the send to occur.	627	for the send to occur.
605		628
606	Example: wait for a timer.	629	Example: wait for a timer.
607		630
608	# wait till the result is ready	631	# condition: "wait till the timer is fired"
609	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
610		633
611	# do something such as adding a timer	634	# create the timer - we could wait for, say
612	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
613	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
614	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
615	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
616	after => 1,	639	after => 1,
617	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
618	);	641	);
619		642
620	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
621	# calls ->send	644	# calls ->send
622	$result_ready->recv;	645	$timer_fired->recv;
623		646
624	Example: wait for a timer, but take advantage of the fact that condition	647	Example: wait for a timer, but take advantage of the fact that condition
625	variables are also callable directly.	648	variables are also callable directly.
626		649
627	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
…		…
670	they were a code reference). Calling them directly is the same as calling	693	they were a code reference). Calling them directly is the same as calling
671	C<send>.	694	C<send>.
672		695
673	=item $cv->croak ($error)	696	=item $cv->croak ($error)
674		697
675	Similar to send, but causes all call's to C<< ->recv >> to invoke	698	Similar to send, but causes all calls to C<< ->recv >> to invoke
676	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
677		700
678	This can be used to signal any errors to the condition variable	701	This can be used to signal any errors to the condition variable
679	user/consumer. Doing it this way instead of calling C<croak> directly	702	user/consumer. Doing it this way instead of calling C<croak> directly
680	delays the error detetcion, but has the overwhelmign advantage that it	703	delays the error detection, but has the overwhelming advantage that it
681	diagnoses the error at the place where the result is expected, and not	704	diagnoses the error at the place where the result is expected, and not
682	deep in some event clalback without connection to the actual code causing	705	deep in some event callback with no connection to the actual code causing
683	the problem.	706	the problem.
684		707
685	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
686		709
687	=item $cv->end	710	=item $cv->end
…		…
725	one call to C<begin>, so the condvar waits for all calls to C<end> before	748	one call to C<begin>, so the condvar waits for all calls to C<end> before
726	sending.	749	sending.
727		750
728	The ping example mentioned above is slightly more complicated, as the	751	The ping example mentioned above is slightly more complicated, as the
729	there are results to be passwd back, and the number of tasks that are	752	there are results to be passwd back, and the number of tasks that are
730	begung can potentially be zero:	753	begun can potentially be zero:
731		754
732	my $cv = AnyEvent->condvar;	755	my $cv = AnyEvent->condvar;
733		756
734	my %result;	757	my %result;
735	$cv->begin (sub { shift->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
…		…
756	to be called once the counter reaches C<0>, and second, it ensures that	779	to be called once the counter reaches C<0>, and second, it ensures that
757	C<send> is called even when C<no> hosts are being pinged (the loop	780	C<send> is called even when C<no> hosts are being pinged (the loop
758	doesn't execute once).	781	doesn't execute once).
759		782
760	This is the general pattern when you "fan out" into multiple (but	783	This is the general pattern when you "fan out" into multiple (but
761	potentially none) subrequests: use an outer C<begin>/C<end> pair to set	784	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
762	the callback and ensure C<end> is called at least once, and then, for each	785	the callback and ensure C<end> is called at least once, and then, for each
763	subrequest you start, call C<begin> and for each subrequest you finish,	786	subrequest you start, call C<begin> and for each subrequest you finish,
764	call C<end>.	787	call C<end>.
765		788
766	=back	789	=back
…		…
773	=over 4	796	=over 4
774		797
775	=item $cv->recv	798	=item $cv->recv
776		799
777	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
778	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
779	normally.	802	normally.
780		803
781	You can only wait once on a condition - additional calls are valid but	804	You can only wait once on a condition - additional calls are valid but
782	will return immediately.	805	will return immediately.
783		806
…		…
800	caller decide whether the call will block or not (for example, by coupling	823	caller decide whether the call will block or not (for example, by coupling
801	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
802	callbacks so the caller knows that getting the result will not block,	825	callbacks so the caller knows that getting the result will not block,
803	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
804		827
805	You can ensure that C<< -recv >> never blocks by setting a callback and	828	You can ensure that C<< ->recv >> never blocks by setting a callback and
806	only calling C<< ->recv >> from within that callback (or at a later	829	only calling C<< ->recv >> from within that callback (or at a later
807	time). This will work even when the event loop does not support blocking	830	time). This will work even when the event loop does not support blocking
808	waits otherwise.	831	waits otherwise.
809		832
810	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
815	=item $cb = $cv->cb ($cb->($cv))	838	=item $cb = $cv->cb ($cb->($cv))
816		839
817	This is a mutator function that returns the callback set and optionally	840	This is a mutator function that returns the callback set and optionally
818	replaces it before doing so.	841	replaces it before doing so.
819		842
820	The callback will be called when the condition becomes (or already was)	843	The callback will be called when the condition becomes "true", i.e. when
821	"true", i.e. when C<send> or C<croak> are called (or were called), with	844	C<send> or C<croak> are called, with the only argument being the
822	the only argument being the condition variable itself. Calling C<recv>	845	condition variable itself. If the condition is already true, the
		846	callback is called immediately when it is set. Calling C<recv> inside
823	inside the callback or at any later time is guaranteed not to block.	847	the callback or at any later time is guaranteed not to block.
824		848
825	=back	849	=back
826		850
827	=head1 SUPPORTED EVENT LOOPS/BACKENDS	851	=head1 SUPPORTED EVENT LOOPS/BACKENDS
828		852
…		…
836	use. If EV is not installed, then AnyEvent will fall back to its own	860	use. If EV is not installed, then AnyEvent will fall back to its own
837	pure-perl implementation, which is available everywhere as it comes with	861	pure-perl implementation, which is available everywhere as it comes with
838	AnyEvent itself.	862	AnyEvent itself.
839		863
840	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	864	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
841	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	865	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
842		866
843	=item Backends that are transparently being picked up when they are used.	867	=item Backends that are transparently being picked up when they are used.
844		868
845	These will be used when they are currently loaded when the first watcher	869	These will be used if they are already loaded when the first watcher
846	is created, in which case it is assumed that the application is using	870	is created, in which case it is assumed that the application is using
847	them. This means that AnyEvent will automatically pick the right backend	871	them. This means that AnyEvent will automatically pick the right backend
848	when the main program loads an event module before anything starts to	872	when the main program loads an event module before anything starts to
849	create watchers. Nothing special needs to be done by the main program.	873	create watchers. Nothing special needs to be done by the main program.
850		874
…		…
852	AnyEvent::Impl::Glib based on Glib, slow but very stable.	876	AnyEvent::Impl::Glib based on Glib, slow but very stable.
853	AnyEvent::Impl::Tk based on Tk, very broken.	877	AnyEvent::Impl::Tk based on Tk, very broken.
854	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	878	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
855	AnyEvent::Impl::POE based on POE, very slow, some limitations.	879	AnyEvent::Impl::POE based on POE, very slow, some limitations.
856	AnyEvent::Impl::Irssi used when running within irssi.	880	AnyEvent::Impl::Irssi used when running within irssi.
		881	AnyEvent::Impl::IOAsync based on IO::Async.
		882	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
		883	AnyEvent::Impl::FLTK2 based on FLTK (fltk 2 binding).
857		884
858	=item Backends with special needs.	885	=item Backends with special needs.
859		886
860	Qt requires the Qt::Application to be instantiated first, but will	887	Qt requires the Qt::Application to be instantiated first, but will
861	otherwise be picked up automatically. As long as the main program	888	otherwise be picked up automatically. As long as the main program
862	instantiates the application before any AnyEvent watchers are created,	889	instantiates the application before any AnyEvent watchers are created,
863	everything should just work.	890	everything should just work.
864		891
865	AnyEvent::Impl::Qt based on Qt.	892	AnyEvent::Impl::Qt based on Qt.
866		893
867	Support for IO::Async can only be partial, as it is too broken and
868	architecturally limited to even support the AnyEvent API. It also
869	is the only event loop that needs the loop to be set explicitly, so
870	it can only be used by a main program knowing about AnyEvent. See
871	L<AnyEvent::Impl::Async> for the gory details.
872
873	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
874
875	=item Event loops that are indirectly supported via other backends.	894	=item Event loops that are indirectly supported via other backends.
876		895
877	Some event loops can be supported via other modules:	896	Some event loops can be supported via other modules:
878		897
879	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.	898	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
…		…
904	Contains C<undef> until the first watcher is being created, before the	923	Contains C<undef> until the first watcher is being created, before the
905	backend has been autodetected.	924	backend has been autodetected.
906		925
907	Afterwards it contains the event model that is being used, which is the	926	Afterwards it contains the event model that is being used, which is the
908	name of the Perl class implementing the model. This class is usually one	927	name of the Perl class implementing the model. This class is usually one
909	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the	928	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
910	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it	929	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
911	will be C<urxvt::anyevent>).	930	will be C<urxvt::anyevent>).
912		931
913	=item AnyEvent::detect	932	=item AnyEvent::detect
914		933
915	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	934	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
916	if necessary. You should only call this function right before you would	935	if necessary. You should only call this function right before you would
917	have created an AnyEvent watcher anyway, that is, as late as possible at	936	have created an AnyEvent watcher anyway, that is, as late as possible at
918	runtime, and not e.g. while initialising of your module.	937	runtime, and not e.g. during initialisation of your module.
919		938
920	If you need to do some initialisation before AnyEvent watchers are	939	If you need to do some initialisation before AnyEvent watchers are
921	created, use C<post_detect>.	940	created, use C<post_detect>.
922		941
923	=item $guard = AnyEvent::post_detect { BLOCK }	942	=item $guard = AnyEvent::post_detect { BLOCK }
924		943
925	Arranges for the code block to be executed as soon as the event model is	944	Arranges for the code block to be executed as soon as the event model is
926	autodetected (or immediately if this has already happened).	945	autodetected (or immediately if that has already happened).
927		946
928	The block will be executed I<after> the actual backend has been detected	947	The block will be executed I<after> the actual backend has been detected
929	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	948	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
930	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	949	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
931	other initialisations - see the sources of L<AnyEvent::Strict> or	950	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
940	that automatically removes the callback again when it is destroyed (or	959	that automatically removes the callback again when it is destroyed (or
941	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for	960	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
942	a case where this is useful.	961	a case where this is useful.
943		962
944	Example: Create a watcher for the IO::AIO module and store it in	963	Example: Create a watcher for the IO::AIO module and store it in
945	C<$WATCHER>. Only do so after the event loop is initialised, though.	964	C<$WATCHER>, but do so only do so after the event loop is initialised.
946		965
947	our WATCHER;	966	our WATCHER;
948		967
949	my $guard = AnyEvent::post_detect {	968	my $guard = AnyEvent::post_detect {
950	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);	969	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
…		…
958	$WATCHER ||= $guard;	977	$WATCHER ||= $guard;
959		978
960	=item @AnyEvent::post_detect	979	=item @AnyEvent::post_detect
961		980
962	If there are any code references in this array (you can C<push> to it	981	If there are any code references in this array (you can C<push> to it
963	before or after loading AnyEvent), then they will called directly after	982	before or after loading AnyEvent), then they will be called directly
964	the event loop has been chosen.	983	after the event loop has been chosen.
965		984
966	You should check C<$AnyEvent::MODEL> before adding to this array, though:	985	You should check C<$AnyEvent::MODEL> before adding to this array, though:
967	if it is defined then the event loop has already been detected, and the	986	if it is defined then the event loop has already been detected, and the
968	array will be ignored.	987	array will be ignored.
969		988
970	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	989	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
971	it,as it takes care of these details.	990	it, as it takes care of these details.
972		991
973	This variable is mainly useful for modules that can do something useful	992	This variable is mainly useful for modules that can do something useful
974	when AnyEvent is used and thus want to know when it is initialised, but do	993	when AnyEvent is used and thus want to know when it is initialised, but do
975	not need to even load it by default. This array provides the means to hook	994	not need to even load it by default. This array provides the means to hook
976	into AnyEvent passively, without loading it.	995	into AnyEvent passively, without loading it.
977		996
		997	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		998	together, you could put this into Coro (this is the actual code used by
		999	Coro to accomplish this):
		1000
		1001	if (defined $AnyEvent::MODEL) {
		1002	# AnyEvent already initialised, so load Coro::AnyEvent
		1003	require Coro::AnyEvent;
		1004	} else {
		1005	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1006	# as soon as it is
		1007	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1008	}
		1009
		1010	=item AnyEvent::postpone { BLOCK }
		1011
		1012	Arranges for the block to be executed as soon as possible, but not before
		1013	the call itself returns. In practise, the block will be executed just
		1014	before the event loop polls for new events, or shortly afterwards.
		1015
		1016	This function never returns anything (to make the C<return postpone { ...
		1017	}> idiom more useful.
		1018
		1019	To understand the usefulness of this function, consider a function that
		1020	asynchronously does something for you and returns some transaction
		1021	object or guard to let you cancel the operation. For example,
		1022	C<AnyEvent::Socket::tcp_connect>:
		1023
		1024	# start a conenction attempt unless one is active
		1025	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1026	delete $self->{connect_guard};
		1027	...
		1028	};
		1029
		1030	Imagine that this function could instantly call the callback, for
		1031	example, because it detects an obvious error such as a negative port
		1032	number. Invoking the callback before the function returns causes problems
		1033	however: the callback will be called and will try to delete the guard
		1034	object. But since the function hasn't returned yet, there is nothing to
		1035	delete. When the function eventually returns it will assign the guard
		1036	object to C<< $self->{connect_guard} >>, where it will likely never be
		1037	deleted, so the program thinks it is still trying to connect.
		1038
		1039	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1040	callback directly on error:
		1041
		1042	$cb->(undef), return # signal error to callback, BAD!
		1043	if $some_error_condition;
		1044
		1045	It should use C<postpone>:
		1046
		1047	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1048	if $some_error_condition;
		1049
978	=back	1050	=back
979		1051
980	=head1 WHAT TO DO IN A MODULE	1052	=head1 WHAT TO DO IN A MODULE
981		1053
982	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1054	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
992	because it will stall the whole program, and the whole point of using	1064	because it will stall the whole program, and the whole point of using
993	events is to stay interactive.	1065	events is to stay interactive.
994		1066
995	It is fine, however, to call C<< ->recv >> when the user of your module	1067	It is fine, however, to call C<< ->recv >> when the user of your module
996	requests it (i.e. if you create a http request object ad have a method	1068	requests it (i.e. if you create a http request object ad have a method
997	called C<results> that returns the results, it should call C<< ->recv >>	1069	called C<results> that returns the results, it may call C<< ->recv >>
998	freely, as the user of your module knows what she is doing. always).	1070	freely, as the user of your module knows what she is doing. Always).
999		1071
1000	=head1 WHAT TO DO IN THE MAIN PROGRAM	1072	=head1 WHAT TO DO IN THE MAIN PROGRAM
1001		1073
1002	There will always be a single main program - the only place that should	1074	There will always be a single main program - the only place that should
1003	dictate which event model to use.	1075	dictate which event model to use.
1004		1076
1005	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1077	If the program is not event-based, it need not do anything special, even
1006	do anything special (it does not need to be event-based) and let AnyEvent	1078	when it depends on a module that uses an AnyEvent. If the program itself
1007	decide which implementation to chose if some module relies on it.	1079	uses AnyEvent, but does not care which event loop is used, all it needs
		1080	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1081	available loop implementation.
1008		1082
1009	If the main program relies on a specific event model - for example, in	1083	If the main program relies on a specific event model - for example, in
1010	Gtk2 programs you have to rely on the Glib module - you should load the	1084	Gtk2 programs you have to rely on the Glib module - you should load the
1011	event module before loading AnyEvent or any module that uses it: generally	1085	event module before loading AnyEvent or any module that uses it: generally
1012	speaking, you should load it as early as possible. The reason is that	1086	speaking, you should load it as early as possible. The reason is that
1013	modules might create watchers when they are loaded, and AnyEvent will	1087	modules might create watchers when they are loaded, and AnyEvent will
1014	decide on the event model to use as soon as it creates watchers, and it	1088	decide on the event model to use as soon as it creates watchers, and it
1015	might chose the wrong one unless you load the correct one yourself.	1089	might choose the wrong one unless you load the correct one yourself.
1016		1090
1017	You can chose to use a pure-perl implementation by loading the	1091	You can chose to use a pure-perl implementation by loading the
1018	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1092	C<AnyEvent::Loop> module, which gives you similar behaviour
1019	everywhere, but letting AnyEvent chose the model is generally better.	1093	everywhere, but letting AnyEvent chose the model is generally better.
1020		1094
1021	=head2 MAINLOOP EMULATION	1095	=head2 MAINLOOP EMULATION
1022		1096
1023	Sometimes (often for short test scripts, or even standalone programs who	1097	Sometimes (often for short test scripts, or even standalone programs who
…		…
1038	=head1 OTHER MODULES	1112	=head1 OTHER MODULES
1039		1113
1040	The following is a non-exhaustive list of additional modules that use	1114	The following is a non-exhaustive list of additional modules that use
1041	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1115	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
1042	modules and other event loops in the same program. Some of the modules	1116	modules and other event loops in the same program. Some of the modules
1043	come with AnyEvent, most are available via CPAN.	1117	come as part of AnyEvent, the others are available via CPAN.
1044		1118
1045	=over 4	1119	=over 4
1046		1120
1047	=item L<AnyEvent::Util>	1121	=item L<AnyEvent::Util>
1048		1122
1049	Contains various utility functions that replace often-used but blocking	1123	Contains various utility functions that replace often-used blocking
1050	functions such as C<inet_aton> by event-/callback-based versions.	1124	functions such as C<inet_aton> with event/callback-based versions.
1051		1125
1052	=item L<AnyEvent::Socket>	1126	=item L<AnyEvent::Socket>
1053		1127
1054	Provides various utility functions for (internet protocol) sockets,	1128	Provides various utility functions for (internet protocol) sockets,
1055	addresses and name resolution. Also functions to create non-blocking tcp	1129	addresses and name resolution. Also functions to create non-blocking tcp
…		…
1057		1131
1058	=item L<AnyEvent::Handle>	1132	=item L<AnyEvent::Handle>
1059		1133
1060	Provide read and write buffers, manages watchers for reads and writes,	1134	Provide read and write buffers, manages watchers for reads and writes,
1061	supports raw and formatted I/O, I/O queued and fully transparent and	1135	supports raw and formatted I/O, I/O queued and fully transparent and
1062	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1136	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1063		1137
1064	=item L<AnyEvent::DNS>	1138	=item L<AnyEvent::DNS>
1065		1139
1066	Provides rich asynchronous DNS resolver capabilities.	1140	Provides rich asynchronous DNS resolver capabilities.
1067		1141
		1142	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1143
		1144	Implement event-based interfaces to the protocols of the same name (for
		1145	the curious, IGS is the International Go Server and FCP is the Freenet
		1146	Client Protocol).
		1147
		1148	=item L<AnyEvent::Handle::UDP>
		1149
		1150	Here be danger!
		1151
		1152	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1153	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1154	its use of a stream-based API with a protocol that isn't streamable, that
		1155	the only way to improve it is to delete it.
		1156
		1157	It features data corruption (but typically only under load) and general
		1158	confusion. On top, the author is not only clueless about UDP but also
		1159	fact-resistant - some gems of his understanding: "connect doesn't work
		1160	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1161	packets", "I don't need to implement proper error checking as UDP doesn't
		1162	support error checking" and so on - he doesn't even understand what's
		1163	wrong with his module when it is explained to him.
		1164
1068	=item L<AnyEvent::HTTP>	1165	=item L<AnyEvent::DBI>
1069		1166
1070	A simple-to-use HTTP library that is capable of making a lot of concurrent	1167	Executes L<DBI> requests asynchronously in a proxy process for you,
1071	HTTP requests.	1168	notifying you in an event-based way when the operation is finished.
		1169
		1170	=item L<AnyEvent::AIO>
		1171
		1172	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1173	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1174	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1175	file I/O, and much more.
1072		1176
1073	=item L<AnyEvent::HTTPD>	1177	=item L<AnyEvent::HTTPD>
1074		1178
1075	Provides a simple web application server framework.	1179	A simple embedded webserver.
1076		1180
1077	=item L<AnyEvent::FastPing>	1181	=item L<AnyEvent::FastPing>
1078		1182
1079	The fastest ping in the west.	1183	The fastest ping in the west.
1080
1081	=item L<AnyEvent::DBI>
1082
1083	Executes L<DBI> requests asynchronously in a proxy process.
1084
1085	=item L<AnyEvent::AIO>
1086
1087	Truly asynchronous I/O, should be in the toolbox of every event
1088	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1089	together.
1090
1091	=item L<AnyEvent::BDB>
1092
1093	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1094	L<BDB> and AnyEvent together.
1095
1096	=item L<AnyEvent::GPSD>
1097
1098	A non-blocking interface to gpsd, a daemon delivering GPS information.
1099
1100	=item L<AnyEvent::IRC>
1101
1102	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1103
1104	=item L<AnyEvent::XMPP>
1105
1106	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1107	Net::XMPP2>.
1108
1109	=item L<AnyEvent::IGS>
1110
1111	A non-blocking interface to the Internet Go Server protocol (used by
1112	L<App::IGS>).
1113
1114	=item L<Net::FCP>
1115
1116	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1117	of AnyEvent.
1118
1119	=item L<Event::ExecFlow>
1120
1121	High level API for event-based execution flow control.
1122		1184
1123	=item L<Coro>	1185	=item L<Coro>
1124		1186
1125	Has special support for AnyEvent via L<Coro::AnyEvent>.	1187	Has special support for AnyEvent via L<Coro::AnyEvent>.
1126		1188
…		…
1130		1192
1131	package AnyEvent;	1193	package AnyEvent;
1132		1194
1133	# basically a tuned-down version of common::sense	1195	# basically a tuned-down version of common::sense
1134	sub common_sense {	1196	sub common_sense {
1135	# from common:.sense 1.0	1197	# from common:.sense 3.4
1136	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x03";	1198	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1137	# use strict vars subs	1199	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1138	$^H |= 0x00000600;	1200	$^H |= 0x00000600;
1139	}	1201	}
1140		1202
1141	BEGIN { AnyEvent::common_sense }	1203	BEGIN { AnyEvent::common_sense }
1142		1204
1143	use Carp ();	1205	use Carp ();
1144		1206
1145	our $VERSION = '5.22';	1207	our $VERSION = '5.34';
1146	our $MODEL;	1208	our $MODEL;
1147		1209
1148	our $AUTOLOAD;
1149	our @ISA;	1210	our @ISA;
1150		1211
1151	our @REGISTRY;	1212	our @REGISTRY;
1152		1213
1153	our $VERBOSE;	1214	our $VERBOSE;
1154		1215
1155	BEGIN {	1216	BEGIN {
1156	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1217	require "AnyEvent/constants.pl";
		1218
1157	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1219	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1158		1220
1159	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1221	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1160	if ${^TAINT};	1222	if ${^TAINT};
1161		1223
1162	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1224	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
…		…
1172	$PROTOCOL{$_} = ++$idx	1234	$PROTOCOL{$_} = ++$idx
1173	for reverse split /\s*,\s*/,	1235	for reverse split /\s*,\s*/,
1174	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1236	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1175	}	1237	}
1176		1238
		1239	our @post_detect;
		1240
		1241	sub post_detect(&) {
		1242	my ($cb) = @_;
		1243
		1244	push @post_detect, $cb;
		1245
		1246	defined wantarray
		1247	? bless \$cb, "AnyEvent::Util::postdetect"
		1248	: ()
		1249	}
		1250
		1251	sub AnyEvent::Util::postdetect::DESTROY {
		1252	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1253	}
		1254
		1255	our $POSTPONE_W;
		1256	our @POSTPONE;
		1257
		1258	sub _postpone_exec {
		1259	undef $POSTPONE_W;
		1260
		1261	&{ shift @POSTPONE }
		1262	while @POSTPONE;
		1263	}
		1264
		1265	sub postpone(&) {
		1266	push @POSTPONE, shift;
		1267
		1268	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1269
		1270	()
		1271	}
		1272
1177	my @models = (	1273	our @models = (
1178	[EV:: => AnyEvent::Impl::EV:: , 1],	1274	[EV:: => AnyEvent::Impl::EV:: , 1],
1179	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],	1275	[AnyEvent::Loop:: => AnyEvent::Impl::Perl:: , 1],
1180	# everything below here will not (normally) be autoprobed	1276	# everything below here will not (normally) be autoprobed
1181	# as the pureperl backend should work everywhere	1277	# as the pure perl backend should work everywhere
1182	# and is usually faster	1278	# and is usually faster
1183	[Event:: => AnyEvent::Impl::Event::, 1],	1279	[Event:: => AnyEvent::Impl::Event::, 1],
1184	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers	1280	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1185	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1281	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1186	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package	1282	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1187	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1283	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1188	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1284	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1189	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1285	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1190	[Wx:: => AnyEvent::Impl::POE::],	1286	[Wx:: => AnyEvent::Impl::POE::],
1191	[Prima:: => AnyEvent::Impl::POE::],	1287	[Prima:: => AnyEvent::Impl::POE::],
1192	# IO::Async is just too broken - we would need workarounds for its	1288	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1193	# byzantine signal and broken child handling, among others.	1289	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1194	# IO::Async is rather hard to detect, as it doesn't have any	1290	[FLTK:: => AnyEvent::Impl::FLTK2::],
1195	# obvious default class.
1196	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1197	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1198	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1199	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1200	);	1291	);
1201		1292
1202	our %method = map +($_ => 1),	1293	# all autoloaded methods reserve the complete glob, not just the method slot.
		1294	# due to bugs in perls method cache implementation.
1203	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1295	our @methods = qw(io timer time now now_update signal child idle condvar);
1204		1296
1205	our @post_detect;
1206
1207	sub post_detect(&) {	1297	sub detect() {
1208	my ($cb) = @_;	1298	local $!; # for good measure
		1299	local $SIG{__DIE__}; # we use eval
1209		1300
1210	if ($MODEL) {	1301	# free some memory
1211	$cb->();	1302	*detect = sub () { $MODEL };
		1303	# undef &func doesn't correctly update the method cache. grmbl.
		1304	# so we delete the whole glob. grmbl.
		1305	# otoh, perl doesn't let me undef an active usb, but it lets me free
		1306	# a glob with an active sub. hrm. i hope it works, but perl is
		1307	# usually buggy in this department. sigh.
		1308	delete @{"AnyEvent::"}{@methods};
		1309	undef @methods;
1212		1310
1213	undef	1311	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1312	my $model = $1;
		1313	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1314	if (eval "require $model") {
		1315	$MODEL = $model;
		1316	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1214	} else {	1317	} else {
1215	push @post_detect, $cb;	1318	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1216		1319	}
1217	defined wantarray
1218	? bless \$cb, "AnyEvent::Util::postdetect"
1219	: ()
1220	}	1320	}
1221	}
1222		1321
1223	sub AnyEvent::Util::postdetect::DESTROY {	1322	# check for already loaded models
1224	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1225	}
1226
1227	sub detect() {
1228	unless ($MODEL) {	1323	unless ($MODEL) {
1229	local $SIG{__DIE__};	1324	for (@REGISTRY, @models) {
1230		1325	my ($package, $model) = @$_;
1231	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1326	if (${"$package\::VERSION"} > 0) {
1232	my $model = "AnyEvent::Impl::$1";
1233	if (eval "require $model") {	1327	if (eval "require $model") {
1234	$MODEL = $model;	1328	$MODEL = $model;
1235	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1329	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1236	} else {	1330	last;
1237	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1331	}
1238	}	1332	}
1239	}	1333	}
1240		1334
1241	# check for already loaded models
1242	unless ($MODEL) {	1335	unless ($MODEL) {
		1336	# try to autoload a model
1243	for (@REGISTRY, @models) {	1337	for (@REGISTRY, @models) {
1244	my ($package, $model) = @$_;	1338	my ($package, $model, $autoload) = @$_;
		1339	if (
		1340	$autoload
		1341	and eval "require $package"
1245	if (${"$package\::VERSION"} > 0) {	1342	and ${"$package\::VERSION"} > 0
1246	if (eval "require $model") {	1343	and eval "require $model"
		1344	) {
1247	$MODEL = $model;	1345	$MODEL = $model;
1248	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;	1346	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1249	last;	1347	last;
1250	}
1251	}	1348	}
1252	}	1349	}
1253		1350
1254	unless ($MODEL) {
1255	# try to autoload a model
1256	for (@REGISTRY, @models) {
1257	my ($package, $model, $autoload) = @$_;
1258	if (
1259	$autoload
1260	and eval "require $package"
1261	and ${"$package\::VERSION"} > 0
1262	and eval "require $model"
1263	) {
1264	$MODEL = $model;
1265	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1266	last;
1267	}
1268	}
1269
1270	$MODEL	1351	$MODEL
1271	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1352	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?\n";
1272	}
1273	}	1353	}
1274
1275	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1276
1277	unshift @ISA, $MODEL;
1278
1279	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1280
1281	(shift @post_detect)->() while @post_detect;
1282	}	1354	}
1283		1355
		1356	# free memory only needed for probing
		1357	undef @models;
		1358	undef @REGISTRY;
		1359
		1360	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1361	unshift @ISA, $MODEL;
		1362
		1363	# now nuke some methods that are overridden by the backend.
		1364	# SUPER usage is not allowed in these.
		1365	for (qw(time signal child idle)) {
		1366	undef &{"AnyEvent::Base::$_"}
		1367	if defined &{"$MODEL\::$_"};
		1368	}
		1369
		1370	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1371	require AnyEvent::Strict;
		1372	}
		1373
		1374	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1375	require AnyEvent::Debug;
		1376	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1377	}
		1378
		1379	if (exists $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1380	require AnyEvent::Socket;
		1381	require AnyEvent::Debug;
		1382
		1383	my ($host, $service) = AnyEvent::Socket::parse_hostport ($ENV{PERL_ANYEVENT_DEBUG_SHELL});
		1384	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1385	}
		1386
		1387	(shift @post_detect)->() while @post_detect;
		1388	undef @post_detect;
		1389
		1390	*post_detect = sub(&) {
		1391	shift->();
		1392
		1393	undef
		1394	};
		1395
1284	$MODEL	1396	$MODEL
1285	}	1397	}
1286		1398
1287	sub AUTOLOAD {	1399	for my $name (@methods) {
1288	(my $func = $AUTOLOAD) =~ s/.*://;	1400	*$name = sub {
1289		1401	detect;
1290	$method{$func}	1402	# we use goto because
1291	or Carp::croak "$func: not a valid method for AnyEvent objects";	1403	# a) it makes the thunk more transparent
1292		1404	# b) it allows us to delete the thunk later
1293	detect unless $MODEL;	1405	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1294		1406	};
1295	my $class = shift;
1296	$class->$func (@_);
1297	}	1407	}
1298		1408
1299	# utility function to dup a filehandle. this is used by many backends	1409	# utility function to dup a filehandle. this is used by many backends
1300	# to support binding more than one watcher per filehandle (they usually	1410	# to support binding more than one watcher per filehandle (they usually
1301	# allow only one watcher per fd, so we dup it to get a different one).	1411	# allow only one watcher per fd, so we dup it to get a different one).
…		…
1315		1425
1316	=head1 SIMPLIFIED AE API	1426	=head1 SIMPLIFIED AE API
1317		1427
1318	Starting with version 5.0, AnyEvent officially supports a second, much	1428	Starting with version 5.0, AnyEvent officially supports a second, much
1319	simpler, API that is designed to reduce the calling, typing and memory	1429	simpler, API that is designed to reduce the calling, typing and memory
1320	overhead.	1430	overhead by using function call syntax and a fixed number of parameters.
1321		1431
1322	See the L<AE> manpage for details.	1432	See the L<AE> manpage for details.
1323		1433
1324	=cut	1434	=cut
1325		1435
1326	package AE;	1436	package AE;
1327		1437
1328	our $VERSION = $AnyEvent::VERSION;	1438	our $VERSION = $AnyEvent::VERSION;
1329		1439
		1440	sub _reset() {
		1441	eval q{
		1442	# fall back to the main API by default - backends and AnyEvent::Base
		1443	# implementations can overwrite these.
		1444
1330	sub io($$$) {	1445	sub io($$$) {
1331	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])	1446	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1332	}	1447	}
1333		1448
1334	sub timer($$$) {	1449	sub timer($$$) {
1335	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])	1450	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1336	}	1451	}
1337		1452
1338	sub signal($$) {	1453	sub signal($$) {
1339	AnyEvent->signal (signal => $_[0], cb => $_[1])	1454	AnyEvent->signal (signal => $_[0], cb => $_[1])
1340	}	1455	}
1341		1456
1342	sub child($$) {	1457	sub child($$) {
1343	AnyEvent->child (pid => $_[0], cb => $_[1])	1458	AnyEvent->child (pid => $_[0], cb => $_[1])
1344	}	1459	}
1345		1460
1346	sub idle($) {	1461	sub idle($) {
1347	AnyEvent->idle (cb => $_[0])	1462	AnyEvent->idle (cb => $_[0]);
1348	}	1463	}
1349		1464
1350	sub cv(;&) {	1465	sub cv(;&) {
1351	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())	1466	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1352	}	1467	}
1353		1468
1354	sub now() {	1469	sub now() {
1355	AnyEvent->now	1470	AnyEvent->now
1356	}	1471	}
1357		1472
1358	sub now_update() {	1473	sub now_update() {
1359	AnyEvent->now_update	1474	AnyEvent->now_update
1360	}	1475	}
1361		1476
1362	sub time() {	1477	sub time() {
1363	AnyEvent->time	1478	AnyEvent->time
		1479	}
		1480
		1481	*postpone = \&AnyEvent::postpone;
		1482	};
		1483	die if $@;
1364	}	1484	}
		1485
		1486	BEGIN { _reset }
1365		1487
1366	package AnyEvent::Base;	1488	package AnyEvent::Base;
1367		1489
1368	# default implementations for many methods	1490	# default implementations for many methods
1369		1491
1370	sub _time() {	1492	sub time {
		1493	eval q{ # poor man's autoloading {}
1371	# probe for availability of Time::HiRes	1494	# probe for availability of Time::HiRes
1372	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1495	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1373	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1496	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1374	*_time = \&Time::HiRes::time;	1497	*AE::time = \&Time::HiRes::time;
1375	# if (eval "use POSIX (); (POSIX::times())...	1498	# if (eval "use POSIX (); (POSIX::times())...
1376	} else {	1499	} else {
1377	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1500	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1378	*_time = sub { time }; # epic fail	1501	*AE::time = sub (){ time }; # epic fail
		1502	}
		1503
		1504	*time = sub { AE::time }; # different prototypes
1379	}	1505	};
		1506	die if $@;
1380		1507
1381	&_time	1508	&time
1382	}	1509	}
1383		1510
1384	sub time { _time }	1511	*now = \&time;
1385	sub now { _time }	1512
1386	sub now_update { }	1513	sub now_update { }
1387		1514
		1515	sub _poll {
		1516	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1517	}
		1518
1388	# default implementation for ->condvar	1519	# default implementation for ->condvar
		1520	# in fact, the default should not be overwritten
1389		1521
1390	sub condvar {	1522	sub condvar {
		1523	eval q{ # poor man's autoloading {}
		1524	*condvar = sub {
1391	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1525	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1526	};
		1527
		1528	*AE::cv = sub (;&) {
		1529	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1530	};
		1531	};
		1532	die if $@;
		1533
		1534	&condvar
1392	}	1535	}
1393		1536
1394	# default implementation for ->signal	1537	# default implementation for ->signal
1395		1538
1396	our $HAVE_ASYNC_INTERRUPT;	1539	our $HAVE_ASYNC_INTERRUPT;
…		…
1405		1548
1406	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1549	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1407	our (%SIG_ASY, %SIG_ASY_W);	1550	our (%SIG_ASY, %SIG_ASY_W);
1408	our ($SIG_COUNT, $SIG_TW);	1551	our ($SIG_COUNT, $SIG_TW);
1409		1552
1410	sub _signal_exec {
1411	$HAVE_ASYNC_INTERRUPT
1412	? $SIGPIPE_R->drain
1413	: sysread $SIGPIPE_R, (my $dummy), 9;
1414
1415	while (%SIG_EV) {
1416	for (keys %SIG_EV) {
1417	delete $SIG_EV{$_};
1418	$_->() for values %{ $SIG_CB{$_} || {} };
1419	}
1420	}
1421	}
1422
1423	# install a dummy wakeup watcher to reduce signal catching latency	1553	# install a dummy wakeup watcher to reduce signal catching latency
		1554	# used by Impls
1424	sub _sig_add() {	1555	sub _sig_add() {
1425	unless ($SIG_COUNT++) {	1556	unless ($SIG_COUNT++) {
1426	# try to align timer on a full-second boundary, if possible	1557	# try to align timer on a full-second boundary, if possible
1427	my $NOW = AE::now;	1558	my $NOW = AE::now;
1428		1559
…		…
1438	undef $SIG_TW	1569	undef $SIG_TW
1439	unless --$SIG_COUNT;	1570	unless --$SIG_COUNT;
1440	}	1571	}
1441		1572
1442	our $_sig_name_init; $_sig_name_init = sub {	1573	our $_sig_name_init; $_sig_name_init = sub {
1443	eval q{ # poor man's autoloading	1574	eval q{ # poor man's autoloading {}
1444	undef $_sig_name_init;	1575	undef $_sig_name_init;
1445		1576
1446	if (_have_async_interrupt) {	1577	if (_have_async_interrupt) {
1447	*sig2num = \&Async::Interrupt::sig2num;	1578	*sig2num = \&Async::Interrupt::sig2num;
1448	*sig2name = \&Async::Interrupt::sig2name;	1579	*sig2name = \&Async::Interrupt::sig2name;
…		…
1480	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;	1611	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1481		1612
1482	} else {	1613	} else {
1483	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;	1614	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1484		1615
1485	require Fcntl;
1486
1487	if (AnyEvent::WIN32) {	1616	if (AnyEvent::WIN32) {
1488	require AnyEvent::Util;	1617	require AnyEvent::Util;
1489		1618
1490	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();	1619	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1491	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;	1620	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1492	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case	1621	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1493	} else {	1622	} else {
1494	pipe $SIGPIPE_R, $SIGPIPE_W;	1623	pipe $SIGPIPE_R, $SIGPIPE_W;
1495	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1624	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1496	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1625	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1497		1626
1498	# not strictly required, as $^F is normally 2, but let's make sure...	1627	# not strictly required, as $^F is normally 2, but let's make sure...
1499	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1628	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1500	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1629	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1501	}	1630	}
1502		1631
1503	$SIGPIPE_R	1632	$SIGPIPE_R
1504	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1633	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1505		1634
1506	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;	1635	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1507	}	1636	}
1508		1637
1509	*signal = sub {	1638	*signal = $HAVE_ASYNC_INTERRUPT
		1639	? sub {
1510	my (undef, %arg) = @_;	1640	my (undef, %arg) = @_;
1511		1641
1512	my $signal = uc $arg{signal}
1513	or Carp::croak "required option 'signal' is missing";
1514
1515	if ($HAVE_ASYNC_INTERRUPT) {
1516	# async::interrupt	1642	# async::interrupt
1517
1518	$signal = sig2num $signal;	1643	my $signal = sig2num $arg{signal};
1519	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1644	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1520		1645
1521	$SIG_ASY{$signal} ||= new Async::Interrupt	1646	$SIG_ASY{$signal} ||= new Async::Interrupt
1522	cb => sub { undef $SIG_EV{$signal} },	1647	cb => sub { undef $SIG_EV{$signal} },
1523	signal => $signal,	1648	signal => $signal,
1524	pipe => [$SIGPIPE_R->filenos],	1649	pipe => [$SIGPIPE_R->filenos],
1525	pipe_autodrain => 0,	1650	pipe_autodrain => 0,
1526	;	1651	;
1527		1652
1528	} else {	1653	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1654	}
		1655	: sub {
		1656	my (undef, %arg) = @_;
		1657
1529	# pure perl	1658	# pure perl
1530
1531	# AE::Util has been loaded in signal
1532	$signal = sig2name $signal;	1659	my $signal = sig2name $arg{signal};
1533	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1660	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1534		1661
1535	$SIG{$signal} ||= sub {	1662	$SIG{$signal} ||= sub {
1536	local $!;	1663	local $!;
1537	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1664	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1538	undef $SIG_EV{$signal};	1665	undef $SIG_EV{$signal};
1539	};	1666	};
1540		1667
1541	# can't do signal processing without introducing races in pure perl,	1668	# can't do signal processing without introducing races in pure perl,
1542	# so limit the signal latency.	1669	# so limit the signal latency.
1543	_sig_add;	1670	_sig_add;
1544	}
1545		1671
1546	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1672	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1673	}
1547	};	1674	;
1548		1675
1549	*AnyEvent::Base::signal::DESTROY = sub {	1676	*AnyEvent::Base::signal::DESTROY = sub {
1550	my ($signal, $cb) = @{$_[0]};	1677	my ($signal, $cb) = @{$_[0]};
1551		1678
1552	_sig_del;	1679	_sig_del;
…		…
1559	# print weird messages, or just unconditionally exit	1686	# print weird messages, or just unconditionally exit
1560	# instead of getting the default action.	1687	# instead of getting the default action.
1561	undef $SIG{$signal}	1688	undef $SIG{$signal}
1562	unless keys %{ $SIG_CB{$signal} };	1689	unless keys %{ $SIG_CB{$signal} };
1563	};	1690	};
		1691
		1692	*_signal_exec = sub {
		1693	$HAVE_ASYNC_INTERRUPT
		1694	? $SIGPIPE_R->drain
		1695	: sysread $SIGPIPE_R, (my $dummy), 9;
		1696
		1697	while (%SIG_EV) {
		1698	for (keys %SIG_EV) {
		1699	delete $SIG_EV{$_};
		1700	&$_ for values %{ $SIG_CB{$_} || {} };
		1701	}
		1702	}
		1703	};
1564	};	1704	};
1565	die if $@;	1705	die if $@;
		1706
1566	&signal	1707	&signal
1567	}	1708	}
1568		1709
1569	# default implementation for ->child	1710	# default implementation for ->child
1570		1711
1571	our %PID_CB;	1712	our %PID_CB;
1572	our $CHLD_W;	1713	our $CHLD_W;
1573	our $CHLD_DELAY_W;	1714	our $CHLD_DELAY_W;
1574	our $WNOHANG;
1575		1715
		1716	# used by many Impl's
1576	sub _emit_childstatus($$) {	1717	sub _emit_childstatus($$) {
1577	my (undef, $rpid, $rstatus) = @_;	1718	my (undef, $rpid, $rstatus) = @_;
1578		1719
1579	$_->($rpid, $rstatus)	1720	$_->($rpid, $rstatus)
1580	for values %{ $PID_CB{$rpid} || {} },	1721	for values %{ $PID_CB{$rpid} || {} },
1581	values %{ $PID_CB{0} || {} };	1722	values %{ $PID_CB{0} || {} };
1582	}	1723	}
1583		1724
1584	sub _sigchld {
1585	my $pid;
1586
1587	AnyEvent->_emit_childstatus ($pid, $?)
1588	while ($pid = waitpid -1, $WNOHANG) > 0;
1589	}
1590
1591	sub child {	1725	sub child {
		1726	eval q{ # poor man's autoloading {}
		1727	*_sigchld = sub {
		1728	my $pid;
		1729
		1730	AnyEvent->_emit_childstatus ($pid, $?)
		1731	while ($pid = waitpid -1, WNOHANG) > 0;
		1732	};
		1733
		1734	*child = sub {
1592	my (undef, %arg) = @_;	1735	my (undef, %arg) = @_;
1593		1736
1594	defined (my $pid = $arg{pid} + 0)	1737	my $pid = $arg{pid};
1595	or Carp::croak "required option 'pid' is missing";	1738	my $cb = $arg{cb};
1596		1739
1597	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1740	$PID_CB{$pid}{$cb+0} = $cb;
1598		1741
1599	# WNOHANG is almost cetrainly 1 everywhere
1600	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1601	? 1
1602	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1603
1604	unless ($CHLD_W) {	1742	unless ($CHLD_W) {
1605	$CHLD_W = AE::signal CHLD => \&_sigchld;	1743	$CHLD_W = AE::signal CHLD => \&_sigchld;
1606	# child could be a zombie already, so make at least one round	1744	# child could be a zombie already, so make at least one round
1607	&_sigchld;	1745	&_sigchld;
1608	}	1746	}
1609		1747
1610	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1748	bless [$pid, $cb+0], "AnyEvent::Base::child"
1611	}	1749	};
1612		1750
1613	sub AnyEvent::Base::child::DESTROY {	1751	*AnyEvent::Base::child::DESTROY = sub {
1614	my ($pid, $cb) = @{$_[0]};	1752	my ($pid, $icb) = @{$_[0]};
1615		1753
1616	delete $PID_CB{$pid}{$cb};	1754	delete $PID_CB{$pid}{$icb};
1617	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1755	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1618		1756
1619	undef $CHLD_W unless keys %PID_CB;	1757	undef $CHLD_W unless keys %PID_CB;
		1758	};
		1759	};
		1760	die if $@;
		1761
		1762	&child
1620	}	1763	}
1621		1764
1622	# idle emulation is done by simply using a timer, regardless	1765	# idle emulation is done by simply using a timer, regardless
1623	# of whether the process is idle or not, and not letting	1766	# of whether the process is idle or not, and not letting
1624	# the callback use more than 50% of the time.	1767	# the callback use more than 50% of the time.
1625	sub idle {	1768	sub idle {
		1769	eval q{ # poor man's autoloading {}
		1770	*idle = sub {
1626	my (undef, %arg) = @_;	1771	my (undef, %arg) = @_;
1627		1772
1628	my ($cb, $w, $rcb) = $arg{cb};	1773	my ($cb, $w, $rcb) = $arg{cb};
1629		1774
1630	$rcb = sub {	1775	$rcb = sub {
1631	if ($cb) {	1776	if ($cb) {
1632	$w = _time;	1777	$w = AE::time;
1633	&$cb;	1778	&$cb;
1634	$w = _time - $w;	1779	$w = AE::time - $w;
1635		1780
1636	# never use more then 50% of the time for the idle watcher,	1781	# never use more then 50% of the time for the idle watcher,
1637	# within some limits	1782	# within some limits
1638	$w = 0.0001 if $w < 0.0001;	1783	$w = 0.0001 if $w < 0.0001;
1639	$w = 5 if $w > 5;	1784	$w = 5 if $w > 5;
1640		1785
1641	$w = AE::timer $w, 0, $rcb;	1786	$w = AE::timer $w, 0, $rcb;
1642	} else {	1787	} else {
1643	# clean up...	1788	# clean up...
1644	undef $w;	1789	undef $w;
1645	undef $rcb;	1790	undef $rcb;
		1791	}
		1792	};
		1793
		1794	$w = AE::timer 0.05, 0, $rcb;
		1795
		1796	bless \\$cb, "AnyEvent::Base::idle"
1646	}	1797	};
		1798
		1799	*AnyEvent::Base::idle::DESTROY = sub {
		1800	undef $${$_[0]};
		1801	};
1647	};	1802	};
		1803	die if $@;
1648		1804
1649	$w = AE::timer 0.05, 0, $rcb;	1805	&idle
1650
1651	bless \\$cb, "AnyEvent::Base::idle"
1652	}
1653
1654	sub AnyEvent::Base::idle::DESTROY {
1655	undef $${$_[0]};
1656	}	1806	}
1657		1807
1658	package AnyEvent::CondVar;	1808	package AnyEvent::CondVar;
1659		1809
1660	our @ISA = AnyEvent::CondVar::Base::;	1810	our @ISA = AnyEvent::CondVar::Base::;
		1811
		1812	# only to be used for subclassing
		1813	sub new {
		1814	my $class = shift;
		1815	bless AnyEvent->condvar (@_), $class
		1816	}
1661		1817
1662	package AnyEvent::CondVar::Base;	1818	package AnyEvent::CondVar::Base;
1663		1819
1664	#use overload	1820	#use overload
1665	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1821	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
…		…
1675		1831
1676	sub _send {	1832	sub _send {
1677	# nop	1833	# nop
1678	}	1834	}
1679		1835
		1836	sub _wait {
		1837	AnyEvent->_poll until $_[0]{_ae_sent};
		1838	}
		1839
1680	sub send {	1840	sub send {
1681	my $cv = shift;	1841	my $cv = shift;
1682	$cv->{_ae_sent} = [@_];	1842	$cv->{_ae_sent} = [@_];
1683	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};	1843	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1684	$cv->_send;	1844	$cv->_send;
…		…
1691		1851
1692	sub ready {	1852	sub ready {
1693	$_[0]{_ae_sent}	1853	$_[0]{_ae_sent}
1694	}	1854	}
1695		1855
1696	sub _wait {
1697	$WAITING
1698	and !$_[0]{_ae_sent}
1699	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1700
1701	local $WAITING = 1;
1702	AnyEvent->one_event while !$_[0]{_ae_sent};
1703	}
1704
1705	sub recv {	1856	sub recv {
		1857	unless ($_[0]{_ae_sent}) {
		1858	$WAITING
		1859	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1860
		1861	local $WAITING = 1;
1706	$_[0]->_wait;	1862	$_[0]->_wait;
		1863	}
1707		1864
1708	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1865	$_[0]{_ae_croak}
1709	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1866	and Carp::croak $_[0]{_ae_croak};
		1867
		1868	wantarray
		1869	? @{ $_[0]{_ae_sent} }
		1870	: $_[0]{_ae_sent}[0]
1710	}	1871	}
1711		1872
1712	sub cb {	1873	sub cb {
1713	my $cv = shift;	1874	my $cv = shift;
1714		1875
…		…
1730	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	1891	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1731	}	1892	}
1732		1893
1733	# undocumented/compatibility with pre-3.4	1894	# undocumented/compatibility with pre-3.4
1734	*broadcast = \&send;	1895	*broadcast = \&send;
1735	*wait = \&_wait;	1896	*wait = \&recv;
1736		1897
1737	=head1 ERROR AND EXCEPTION HANDLING	1898	=head1 ERROR AND EXCEPTION HANDLING
1738		1899
1739	In general, AnyEvent does not do any error handling - it relies on the	1900	In general, AnyEvent does not do any error handling - it relies on the
1740	caller to do that if required. The L<AnyEvent::Strict> module (see also	1901	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1787	check the arguments passed to most method calls. If it finds any problems,	1948	check the arguments passed to most method calls. If it finds any problems,
1788	it will croak.	1949	it will croak.
1789		1950
1790	In other words, enables "strict" mode.	1951	In other words, enables "strict" mode.
1791		1952
1792	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	1953	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1793	>>, it is definitely recommended to keep it off in production. Keeping	1954	>>, it is definitely recommended to keep it off in production. Keeping
1794	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	1955	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1795	can be very useful, however.	1956	can be very useful, however.
1796		1957
		1958	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		1959
		1960	If this env variable is set, then its contents will be
		1961	interpreted by C<AnyEvent::Socket::parse_hostport> and an
		1962	C<AnyEvent::Debug::shell> is bound on that port. The shell object is saved
		1963	in C<$AnyEvent::Debug::SHELL>.
		1964
		1965	For example, to bind a debug shell on a unix domain socket in
		1966	F</tmp/debug.sock>, you could use this:
		1967
		1968	PERL_ANYEVENT_DEBUG_SHELL=unix/:/tmp/debug.sock perlprog
		1969
		1970	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		1971
		1972	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		1973	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
		1974
1797	=item C<PERL_ANYEVENT_MODEL>	1975	=item C<PERL_ANYEVENT_MODEL>
1798		1976
1799	This can be used to specify the event model to be used by AnyEvent, before	1977	This can be used to specify the event model to be used by AnyEvent, before
1800	auto detection and -probing kicks in. It must be a string consisting	1978	auto detection and -probing kicks in.
1801	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1979
		1980	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		1981	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1802	and the resulting module name is loaded and if the load was successful,	1982	resulting module name is loaded and - if the load was successful - used as
1803	used as event model. If it fails to load AnyEvent will proceed with	1983	event model backend. If it fails to load then AnyEvent will proceed with
1804	auto detection and -probing.	1984	auto detection and -probing.
1805		1985
1806	This functionality might change in future versions.	1986	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		1987	nothing gets prepended and the module name is used as-is (hint: C<::> at
		1988	the end of a string designates a module name and quotes it appropriately).
1807		1989
1808	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1990	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1809	could start your program like this:	1991	could start your program like this:
1810		1992
1811	PERL_ANYEVENT_MODEL=Perl perl ...	1993	PERL_ANYEVENT_MODEL=Perl perl ...
1812		1994
1813	=item C<PERL_ANYEVENT_PROTOCOLS>	1995	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
2019		2201
2020	The actual code goes further and collects all errors (C<die>s, exceptions)	2202	The actual code goes further and collects all errors (C<die>s, exceptions)
2021	that occurred during request processing. The C<result> method detects	2203	that occurred during request processing. The C<result> method detects
2022	whether an exception as thrown (it is stored inside the $txn object)	2204	whether an exception as thrown (it is stored inside the $txn object)
2023	and just throws the exception, which means connection errors and other	2205	and just throws the exception, which means connection errors and other
2024	problems get reported tot he code that tries to use the result, not in a	2206	problems get reported to the code that tries to use the result, not in a
2025	random callback.	2207	random callback.
2026		2208
2027	All of this enables the following usage styles:	2209	All of this enables the following usage styles:
2028		2210
2029	1. Blocking:	2211	1. Blocking:
…		…
2443	unless defined $SIG{PIPE};	2625	unless defined $SIG{PIPE};
2444		2626
2445	=head1 RECOMMENDED/OPTIONAL MODULES	2627	=head1 RECOMMENDED/OPTIONAL MODULES
2446		2628
2447	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2629	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2448	it's built-in modules) are required to use it.	2630	its built-in modules) are required to use it.
2449		2631
2450	That does not mean that AnyEvent won't take advantage of some additional	2632	That does not mean that AnyEvent won't take advantage of some additional
2451	modules if they are installed.	2633	modules if they are installed.
2452		2634
2453	This section explains which additional modules will be used, and how they	2635	This section explains which additional modules will be used, and how they
…		…
2486	automatic timer adjustments even when no monotonic clock is available,	2668	automatic timer adjustments even when no monotonic clock is available,
2487	can take avdantage of advanced kernel interfaces such as C<epoll> and	2669	can take avdantage of advanced kernel interfaces such as C<epoll> and
2488	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2670	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2489	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2671	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2490		2672
		2673	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2674	then this module will do nothing for you.
		2675
2491	=item L<Guard>	2676	=item L<Guard>
2492		2677
2493	The guard module, when used, will be used to implement	2678	The guard module, when used, will be used to implement
2494	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2679	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2495	lot less memory), but otherwise doesn't affect guard operation much. It is	2680	lot less memory), but otherwise doesn't affect guard operation much. It is
2496	purely used for performance.	2681	purely used for performance.
2497		2682
2498	=item L<JSON> and L<JSON::XS>	2683	=item L<JSON> and L<JSON::XS>
2499		2684
2500	One of these modules is required when you want to read or write JSON data	2685	One of these modules is required when you want to read or write JSON data
2501	via L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2686	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2502	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.	2687	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2503
2504	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2505	installed.
2506		2688
2507	=item L<Net::SSLeay>	2689	=item L<Net::SSLeay>
2508		2690
2509	Implementing TLS/SSL in Perl is certainly interesting, but not very	2691	Implementing TLS/SSL in Perl is certainly interesting, but not very
2510	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2692	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2511	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2693	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2512		2694
2513	=item L<Time::HiRes>	2695	=item L<Time::HiRes>
2514		2696
2515	This module is part of perl since release 5.008. It will be used when the	2697	This module is part of perl since release 5.008. It will be used when the
2516	chosen event library does not come with a timing source on it's own. The	2698	chosen event library does not come with a timing source of its own. The
2517	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2699	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2518	try to use a monotonic clock for timing stability.	2700	try to use a monotonic clock for timing stability.
2519		2701
2520	=back	2702	=back
2521		2703
2522		2704
2523	=head1 FORK	2705	=head1 FORK
2524		2706
2525	Most event libraries are not fork-safe. The ones who are usually are	2707	Most event libraries are not fork-safe. The ones who are usually are
2526	because they rely on inefficient but fork-safe C<select> or C<poll>	2708	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2527	calls. Only L<EV> is fully fork-aware.	2709	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2710	are usually badly thought-out hacks that are incompatible with fork in
		2711	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2712	continue event-processing in both parent and child (or both, if you know
		2713	what you are doing).
2528		2714
2529	This means that, in general, you cannot fork and do event processing	2715	This means that, in general, you cannot fork and do event processing in
2530	in the child if a watcher was created before the fork (which in turn	2716	the child if the event library was initialised before the fork (which
2531	initialises the event library).	2717	usually happens when the first AnyEvent watcher is created, or the library
		2718	is loaded).
2532		2719
2533	If you have to fork, you must either do so I<before> creating your first	2720	If you have to fork, you must either do so I<before> creating your first
2534	watcher OR you must not use AnyEvent at all in the child OR you must do	2721	watcher OR you must not use AnyEvent at all in the child OR you must do
2535	something completely out of the scope of AnyEvent.	2722	something completely out of the scope of AnyEvent.
2536		2723
2537	The problem of doing event processing in the parent I<and> the child	2724	The problem of doing event processing in the parent I<and> the child
2538	is much more complicated: even for backends that I<are> fork-aware or	2725	is much more complicated: even for backends that I<are> fork-aware or
2539	fork-safe, their behaviour is not usually what you want: fork clones all	2726	fork-safe, their behaviour is not usually what you want: fork clones all
2540	watchers, that means all timers, I/O watchers etc. are active in both	2727	watchers, that means all timers, I/O watchers etc. are active in both
2541	parent and child, which is almost never what you want.	2728	parent and child, which is almost never what you want. USing C<exec>
		2729	to start worker children from some kind of manage rprocess is usually
		2730	preferred, because it is much easier and cleaner, at the expense of having
		2731	to have another binary.
2542		2732
2543		2733
2544	=head1 SECURITY CONSIDERATIONS	2734	=head1 SECURITY CONSIDERATIONS
2545		2735
2546	AnyEvent can be forced to load any event model via	2736	AnyEvent can be forced to load any event model via
…		…
2576	pronounced).	2766	pronounced).
2577		2767
2578		2768
2579	=head1 SEE ALSO	2769	=head1 SEE ALSO
2580		2770
		2771	Tutorial/Introduction: L<AnyEvent::Intro>.
		2772
		2773	FAQ: L<AnyEvent::FAQ>.
		2774
2581	Utility functions: L<AnyEvent::Util>.	2775	Utility functions: L<AnyEvent::Util>.
2582		2776
2583	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2777	Event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>, L<Glib::EV>,
2584	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2778	L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2585		2779
2586	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2780	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2587	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2781	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2588	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2782	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2589	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.	2783	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
…		…
2591	Non-blocking file handles, sockets, TCP clients and	2785	Non-blocking file handles, sockets, TCP clients and
2592	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2786	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2593		2787
2594	Asynchronous DNS: L<AnyEvent::DNS>.	2788	Asynchronous DNS: L<AnyEvent::DNS>.
2595		2789
2596	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	2790	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2597	L<Coro::Event>,
2598		2791
2599	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	2792	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2600	L<AnyEvent::HTTP>.	2793	L<AnyEvent::HTTP>.
2601		2794
2602		2795
2603	=head1 AUTHOR	2796	=head1 AUTHOR
2604		2797

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