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Revision 1.306 by root, Tue Dec 15 05:49:13 2009 UTC vs.
Revision 1.356 by root, Fri Aug 12 18:41:25 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 {
…		…
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
…		…
986	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent	1005	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
987	# as soon as it is	1006	# as soon as it is
988	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };	1007	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
989	}	1008	}
990		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
991	=back	1050	=back
992		1051
993	=head1 WHAT TO DO IN A MODULE	1052	=head1 WHAT TO DO IN A MODULE
994		1053
995	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
…		…
1005	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
1006	events is to stay interactive.	1065	events is to stay interactive.
1007		1066
1008	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
1009	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
1010	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 >>
1011	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).
1012		1071
1013	=head1 WHAT TO DO IN THE MAIN PROGRAM	1072	=head1 WHAT TO DO IN THE MAIN PROGRAM
1014		1073
1015	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
1016	dictate which event model to use.	1075	dictate which event model to use.
1017		1076
1018	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
1019	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
1020	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.
1021		1082
1022	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
1023	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
1024	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
1025	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
1026	modules might create watchers when they are loaded, and AnyEvent will	1087	modules might create watchers when they are loaded, and AnyEvent will
1027	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
1028	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.
1029		1090
1030	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
1031	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1092	C<AnyEvent::Loop> module, which gives you similar behaviour
1032	everywhere, but letting AnyEvent chose the model is generally better.	1093	everywhere, but letting AnyEvent chose the model is generally better.
1033		1094
1034	=head2 MAINLOOP EMULATION	1095	=head2 MAINLOOP EMULATION
1035		1096
1036	Sometimes (often for short test scripts, or even standalone programs who	1097	Sometimes (often for short test scripts, or even standalone programs who
…		…
1051	=head1 OTHER MODULES	1112	=head1 OTHER MODULES
1052		1113
1053	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
1054	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
1055	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
1056	come with AnyEvent, most are available via CPAN.	1117	come as part of AnyEvent, the others are available via CPAN.
1057		1118
1058	=over 4	1119	=over 4
1059		1120
1060	=item L<AnyEvent::Util>	1121	=item L<AnyEvent::Util>
1061		1122
1062	Contains various utility functions that replace often-used but blocking	1123	Contains various utility functions that replace often-used blocking
1063	functions such as C<inet_aton> by event-/callback-based versions.	1124	functions such as C<inet_aton> with event/callback-based versions.
1064		1125
1065	=item L<AnyEvent::Socket>	1126	=item L<AnyEvent::Socket>
1066		1127
1067	Provides various utility functions for (internet protocol) sockets,	1128	Provides various utility functions for (internet protocol) sockets,
1068	addresses and name resolution. Also functions to create non-blocking tcp	1129	addresses and name resolution. Also functions to create non-blocking tcp
…		…
1070		1131
1071	=item L<AnyEvent::Handle>	1132	=item L<AnyEvent::Handle>
1072		1133
1073	Provide read and write buffers, manages watchers for reads and writes,	1134	Provide read and write buffers, manages watchers for reads and writes,
1074	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
1075	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1136	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1076		1137
1077	=item L<AnyEvent::DNS>	1138	=item L<AnyEvent::DNS>
1078		1139
1079	Provides rich asynchronous DNS resolver capabilities.	1140	Provides rich asynchronous DNS resolver capabilities.
1080		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
1081	=item L<AnyEvent::HTTP>	1165	=item L<AnyEvent::DBI>
1082		1166
1083	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,
1084	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.
1085		1176
1086	=item L<AnyEvent::HTTPD>	1177	=item L<AnyEvent::HTTPD>
1087		1178
1088	Provides a simple web application server framework.	1179	A simple embedded webserver.
1089		1180
1090	=item L<AnyEvent::FastPing>	1181	=item L<AnyEvent::FastPing>
1091		1182
1092	The fastest ping in the west.	1183	The fastest ping in the west.
1093
1094	=item L<AnyEvent::DBI>
1095
1096	Executes L<DBI> requests asynchronously in a proxy process.
1097
1098	=item L<AnyEvent::AIO>
1099
1100	Truly asynchronous I/O, should be in the toolbox of every event
1101	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1102	together.
1103
1104	=item L<AnyEvent::BDB>
1105
1106	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1107	L<BDB> and AnyEvent together.
1108
1109	=item L<AnyEvent::GPSD>
1110
1111	A non-blocking interface to gpsd, a daemon delivering GPS information.
1112
1113	=item L<AnyEvent::IRC>
1114
1115	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1116
1117	=item L<AnyEvent::XMPP>
1118
1119	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1120	Net::XMPP2>.
1121
1122	=item L<AnyEvent::IGS>
1123
1124	A non-blocking interface to the Internet Go Server protocol (used by
1125	L<App::IGS>).
1126
1127	=item L<Net::FCP>
1128
1129	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1130	of AnyEvent.
1131
1132	=item L<Event::ExecFlow>
1133
1134	High level API for event-based execution flow control.
1135		1184
1136	=item L<Coro>	1185	=item L<Coro>
1137		1186
1138	Has special support for AnyEvent via L<Coro::AnyEvent>.	1187	Has special support for AnyEvent via L<Coro::AnyEvent>.
1139		1188
…		…
1143		1192
1144	package AnyEvent;	1193	package AnyEvent;
1145		1194
1146	# basically a tuned-down version of common::sense	1195	# basically a tuned-down version of common::sense
1147	sub common_sense {	1196	sub common_sense {
1148	# from common:.sense 1.0	1197	# from common:.sense 3.4
1149	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";	1198	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1150	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)	1199	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1151	$^H |= 0x00000600;	1200	$^H |= 0x00000600;
1152	}	1201	}
1153		1202
1154	BEGIN { AnyEvent::common_sense }	1203	BEGIN { AnyEvent::common_sense }
1155		1204
1156	use Carp ();	1205	use Carp ();
1157		1206
1158	our $VERSION = '5.22';	1207	our $VERSION = '5.34';
1159	our $MODEL;	1208	our $MODEL;
1160		1209
1161	our $AUTOLOAD;	1210	our $AUTOLOAD;
1162	our @ISA;	1211	our @ISA;
1163		1212
1164	our @REGISTRY;	1213	our @REGISTRY;
1165		1214
1166	our $VERBOSE;	1215	our $VERBOSE;
1167		1216
1168	BEGIN {	1217	BEGIN {
1169	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1218	require "AnyEvent/constants.pl";
		1219
1170	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1220	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1171		1221
1172	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1222	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1173	if ${^TAINT};	1223	if ${^TAINT};
1174		1224
1175	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1225	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
…		…
1185	$PROTOCOL{$_} = ++$idx	1235	$PROTOCOL{$_} = ++$idx
1186	for reverse split /\s*,\s*/,	1236	for reverse split /\s*,\s*/,
1187	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1237	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1188	}	1238	}
1189		1239
		1240	our @post_detect;
		1241
		1242	sub post_detect(&) {
		1243	my ($cb) = @_;
		1244
		1245	push @post_detect, $cb;
		1246
		1247	defined wantarray
		1248	? bless \$cb, "AnyEvent::Util::postdetect"
		1249	: ()
		1250	}
		1251
		1252	sub AnyEvent::Util::postdetect::DESTROY {
		1253	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1254	}
		1255
		1256	our $POSTPONE_W;
		1257	our @POSTPONE;
		1258
		1259	sub _postpone_exec {
		1260	undef $POSTPONE_W;
		1261
		1262	&{ shift @POSTPONE }
		1263	while @POSTPONE;
		1264	}
		1265
		1266	sub postpone(&) {
		1267	push @POSTPONE, shift;
		1268
		1269	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1270
		1271	()
		1272	}
		1273
1190	my @models = (	1274	our @models = (
1191	[EV:: => AnyEvent::Impl::EV:: , 1],	1275	[EV:: => AnyEvent::Impl::EV:: , 1],
1192	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],	1276	[AnyEvent::Loop:: => AnyEvent::Impl::Perl:: , 1],
1193	# everything below here will not (normally) be autoprobed	1277	# everything below here will not (normally) be autoprobed
1194	# as the pureperl backend should work everywhere	1278	# as the pure perl backend should work everywhere
1195	# and is usually faster	1279	# and is usually faster
1196	[Event:: => AnyEvent::Impl::Event::, 1],	1280	[Event:: => AnyEvent::Impl::Event::, 1],
1197	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers	1281	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1198	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1282	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1199	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package	1283	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1200	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1284	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1201	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1285	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1202	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1286	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1203	[Wx:: => AnyEvent::Impl::POE::],	1287	[Wx:: => AnyEvent::Impl::POE::],
1204	[Prima:: => AnyEvent::Impl::POE::],	1288	[Prima:: => AnyEvent::Impl::POE::],
1205	# IO::Async is just too broken - we would need workarounds for its	1289	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1206	# byzantine signal and broken child handling, among others.	1290	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1207	# IO::Async is rather hard to detect, as it doesn't have any	1291	[FLTK:: => AnyEvent::Impl::FLTK2::],
1208	# obvious default class.
1209	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1210	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1211	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1212	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1213	);	1292	);
1214		1293
1215	our %method = map +($_ => 1),
1216	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
1217
1218	our @post_detect;
1219
1220	sub post_detect(&) {	1294	sub detect() {
1221	my ($cb) = @_;	1295	# free some memory
		1296	*detect = sub () { $MODEL };
1222		1297
1223	if ($MODEL) {	1298	local $!; # for good measure
1224	$cb->();	1299	local $SIG{__DIE__};
1225		1300
1226	undef	1301	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1302	my $model = $1;
		1303	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1304	if (eval "require $model") {
		1305	$MODEL = $model;
		1306	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1227	} else {	1307	} else {
1228	push @post_detect, $cb;	1308	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1229		1309	}
1230	defined wantarray
1231	? bless \$cb, "AnyEvent::Util::postdetect"
1232	: ()
1233	}	1310	}
1234	}
1235		1311
1236	sub AnyEvent::Util::postdetect::DESTROY {	1312	# check for already loaded models
1237	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1238	}
1239
1240	sub detect() {
1241	unless ($MODEL) {	1313	unless ($MODEL) {
1242	local $SIG{__DIE__};	1314	for (@REGISTRY, @models) {
1243		1315	my ($package, $model) = @$_;
1244	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1316	if (${"$package\::VERSION"} > 0) {
1245	my $model = "AnyEvent::Impl::$1";
1246	if (eval "require $model") {	1317	if (eval "require $model") {
1247	$MODEL = $model;	1318	$MODEL = $model;
1248	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1319	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1249	} else {	1320	last;
1250	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1321	}
1251	}	1322	}
1252	}	1323	}
1253		1324
1254	# check for already loaded models
1255	unless ($MODEL) {	1325	unless ($MODEL) {
		1326	# try to autoload a model
1256	for (@REGISTRY, @models) {	1327	for (@REGISTRY, @models) {
1257	my ($package, $model) = @$_;	1328	my ($package, $model, $autoload) = @$_;
		1329	if (
		1330	$autoload
		1331	and eval "require $package"
1258	if (${"$package\::VERSION"} > 0) {	1332	and ${"$package\::VERSION"} > 0
1259	if (eval "require $model") {	1333	and eval "require $model"
		1334	) {
1260	$MODEL = $model;	1335	$MODEL = $model;
1261	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;	1336	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1262	last;	1337	last;
1263	}
1264	}	1338	}
1265	}	1339	}
1266		1340
1267	unless ($MODEL) {
1268	# try to autoload a model
1269	for (@REGISTRY, @models) {
1270	my ($package, $model, $autoload) = @$_;
1271	if (
1272	$autoload
1273	and eval "require $package"
1274	and ${"$package\::VERSION"} > 0
1275	and eval "require $model"
1276	) {
1277	$MODEL = $model;
1278	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1279	last;
1280	}
1281	}
1282
1283	$MODEL	1341	$MODEL
1284	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1342	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?\n";
1285	}
1286	}	1343	}
1287
1288	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1289
1290	unshift @ISA, $MODEL;
1291
1292	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1293
1294	(shift @post_detect)->() while @post_detect;
1295	}	1344	}
1296		1345
		1346	# free memory only needed for probing
		1347	undef @models;
		1348	undef @REGISTRY;
		1349
		1350	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1351	unshift @ISA, $MODEL;
		1352
		1353	# now nuke some methods that are overridden by the backend.
		1354	# SUPER usage is not allowed in these.
		1355	for (qw(time signal child idle)) {
		1356	undef &{"AnyEvent::Base::$_"}
		1357	if defined &{"$MODEL\::$_"};
		1358	}
		1359
		1360	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1361	eval { require AnyEvent::Strict };
		1362	warn "AnyEvent: cannot load AnyEvent::Strict: $@"
		1363	if $@ && $VERBOSE;
		1364	}
		1365
		1366	(shift @post_detect)->() while @post_detect;
		1367	undef @post_detect;
		1368
		1369	*post_detect = sub(&) {
		1370	shift->();
		1371
		1372	undef
		1373	};
		1374
		1375	# recover a few more bytes
		1376	postpone {
		1377	undef &AUTOLOAD;
		1378	};
		1379
1297	$MODEL	1380	$MODEL
1298	}	1381	}
		1382
		1383	our %method = map +($_ => 1),
		1384	qw(io timer time now now_update signal child idle condvar DESTROY);
1299		1385
1300	sub AUTOLOAD {	1386	sub AUTOLOAD {
1301	(my $func = $AUTOLOAD) =~ s/.*://;	1387	(my $func = $AUTOLOAD) =~ s/.*://;
1302		1388
1303	$method{$func}	1389	$method{$func}
1304	or Carp::croak "$func: not a valid method for AnyEvent objects";	1390	or Carp::croak "$func: not a valid AnyEvent class method";
1305		1391
1306	detect unless $MODEL;	1392	# free some memory
		1393	undef %method;
		1394
		1395	detect;
1307		1396
1308	my $class = shift;	1397	my $class = shift;
1309	$class->$func (@_);	1398	$class->$func (@_);
1310	}	1399	}
1311		1400
…		…
1328		1417
1329	=head1 SIMPLIFIED AE API	1418	=head1 SIMPLIFIED AE API
1330		1419
1331	Starting with version 5.0, AnyEvent officially supports a second, much	1420	Starting with version 5.0, AnyEvent officially supports a second, much
1332	simpler, API that is designed to reduce the calling, typing and memory	1421	simpler, API that is designed to reduce the calling, typing and memory
1333	overhead.	1422	overhead by using function call syntax and a fixed number of parameters.
1334		1423
1335	See the L<AE> manpage for details.	1424	See the L<AE> manpage for details.
1336		1425
1337	=cut	1426	=cut
1338		1427
1339	package AE;	1428	package AE;
1340		1429
1341	our $VERSION = $AnyEvent::VERSION;	1430	our $VERSION = $AnyEvent::VERSION;
1342		1431
		1432
		1433	sub _reset() {
		1434	eval q{
		1435	# fall back to the main API by default - backends and AnyEvent::Base
		1436	# implementations can overwrite these.
		1437
1343	sub io($$$) {	1438	sub io($$$) {
1344	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])	1439	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1345	}	1440	}
1346		1441
1347	sub timer($$$) {	1442	sub timer($$$) {
1348	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])	1443	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1349	}	1444	}
1350		1445
1351	sub signal($$) {	1446	sub signal($$) {
1352	AnyEvent->signal (signal => $_[0], cb => $_[1])	1447	AnyEvent->signal (signal => $_[0], cb => $_[1])
1353	}	1448	}
1354		1449
1355	sub child($$) {	1450	sub child($$) {
1356	AnyEvent->child (pid => $_[0], cb => $_[1])	1451	AnyEvent->child (pid => $_[0], cb => $_[1])
1357	}	1452	}
1358		1453
1359	sub idle($) {	1454	sub idle($) {
1360	AnyEvent->idle (cb => $_[0])	1455	AnyEvent->idle (cb => $_[0])
1361	}	1456	}
1362		1457
1363	sub cv(;&) {	1458	sub cv(;&) {
1364	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())	1459	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1365	}	1460	}
1366		1461
1367	sub now() {	1462	sub now() {
1368	AnyEvent->now	1463	AnyEvent->now
1369	}	1464	}
1370		1465
1371	sub now_update() {	1466	sub now_update() {
1372	AnyEvent->now_update	1467	AnyEvent->now_update
1373	}	1468	}
1374		1469
1375	sub time() {	1470	sub time() {
1376	AnyEvent->time	1471	AnyEvent->time
		1472	}
		1473
		1474	*postpone = \&AnyEvent::postpone;
		1475	};
		1476	die if $@;
1377	}	1477	}
		1478
		1479	BEGIN { _reset }
1378		1480
1379	package AnyEvent::Base;	1481	package AnyEvent::Base;
1380		1482
1381	# default implementations for many methods	1483	# default implementations for many methods
1382		1484
1383	sub _time() {	1485	sub time {
		1486	eval q{ # poor man's autoloading {}
1384	# probe for availability of Time::HiRes	1487	# probe for availability of Time::HiRes
1385	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1488	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1386	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1489	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1387	*_time = \&Time::HiRes::time;	1490	*AE::time = \&Time::HiRes::time;
1388	# if (eval "use POSIX (); (POSIX::times())...	1491	# if (eval "use POSIX (); (POSIX::times())...
1389	} else {	1492	} else {
1390	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1493	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1391	*_time = sub { time }; # epic fail	1494	*AE::time = sub (){ time }; # epic fail
		1495	}
		1496
		1497	*time = sub { AE::time }; # different prototypes
1392	}	1498	};
		1499	die if $@;
1393		1500
1394	&_time	1501	&time
1395	}	1502	}
1396		1503
1397	sub time { _time }	1504	*now = \&time;
1398	sub now { _time }	1505
1399	sub now_update { }	1506	sub now_update { }
1400		1507
		1508	sub _poll {
		1509	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1510	}
		1511
1401	# default implementation for ->condvar	1512	# default implementation for ->condvar
		1513	# in fact, the default should not be overwritten
1402		1514
1403	sub condvar {	1515	sub condvar {
		1516	eval q{ # poor man's autoloading {}
		1517	*condvar = sub {
1404	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1518	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1519	};
		1520
		1521	*AE::cv = sub (;&) {
		1522	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1523	};
		1524	};
		1525	die if $@;
		1526
		1527	&condvar
1405	}	1528	}
1406		1529
1407	# default implementation for ->signal	1530	# default implementation for ->signal
1408		1531
1409	our $HAVE_ASYNC_INTERRUPT;	1532	our $HAVE_ASYNC_INTERRUPT;
…		…
1418		1541
1419	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1542	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1420	our (%SIG_ASY, %SIG_ASY_W);	1543	our (%SIG_ASY, %SIG_ASY_W);
1421	our ($SIG_COUNT, $SIG_TW);	1544	our ($SIG_COUNT, $SIG_TW);
1422		1545
1423	sub _signal_exec {
1424	$HAVE_ASYNC_INTERRUPT
1425	? $SIGPIPE_R->drain
1426	: sysread $SIGPIPE_R, (my $dummy), 9;
1427
1428	while (%SIG_EV) {
1429	for (keys %SIG_EV) {
1430	delete $SIG_EV{$_};
1431	$_->() for values %{ $SIG_CB{$_} || {} };
1432	}
1433	}
1434	}
1435
1436	# install a dummy wakeup watcher to reduce signal catching latency	1546	# install a dummy wakeup watcher to reduce signal catching latency
		1547	# used by Impls
1437	sub _sig_add() {	1548	sub _sig_add() {
1438	unless ($SIG_COUNT++) {	1549	unless ($SIG_COUNT++) {
1439	# try to align timer on a full-second boundary, if possible	1550	# try to align timer on a full-second boundary, if possible
1440	my $NOW = AE::now;	1551	my $NOW = AE::now;
1441		1552
…		…
1451	undef $SIG_TW	1562	undef $SIG_TW
1452	unless --$SIG_COUNT;	1563	unless --$SIG_COUNT;
1453	}	1564	}
1454		1565
1455	our $_sig_name_init; $_sig_name_init = sub {	1566	our $_sig_name_init; $_sig_name_init = sub {
1456	eval q{ # poor man's autoloading	1567	eval q{ # poor man's autoloading {}
1457	undef $_sig_name_init;	1568	undef $_sig_name_init;
1458		1569
1459	if (_have_async_interrupt) {	1570	if (_have_async_interrupt) {
1460	*sig2num = \&Async::Interrupt::sig2num;	1571	*sig2num = \&Async::Interrupt::sig2num;
1461	*sig2name = \&Async::Interrupt::sig2name;	1572	*sig2name = \&Async::Interrupt::sig2name;
…		…
1493	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;	1604	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1494		1605
1495	} else {	1606	} else {
1496	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;	1607	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1497		1608
1498	require Fcntl;
1499
1500	if (AnyEvent::WIN32) {	1609	if (AnyEvent::WIN32) {
1501	require AnyEvent::Util;	1610	require AnyEvent::Util;
1502		1611
1503	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();	1612	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1504	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;	1613	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1505	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case	1614	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1506	} else {	1615	} else {
1507	pipe $SIGPIPE_R, $SIGPIPE_W;	1616	pipe $SIGPIPE_R, $SIGPIPE_W;
1508	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1617	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1509	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1618	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1510		1619
1511	# not strictly required, as $^F is normally 2, but let's make sure...	1620	# not strictly required, as $^F is normally 2, but let's make sure...
1512	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1621	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1513	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1622	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1514	}	1623	}
1515		1624
1516	$SIGPIPE_R	1625	$SIGPIPE_R
1517	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1626	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1518		1627
1519	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;	1628	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1520	}	1629	}
1521		1630
1522	*signal = sub {	1631	*signal = $HAVE_ASYNC_INTERRUPT
		1632	? sub {
1523	my (undef, %arg) = @_;	1633	my (undef, %arg) = @_;
1524		1634
1525	my $signal = uc $arg{signal}
1526	or Carp::croak "required option 'signal' is missing";
1527
1528	if ($HAVE_ASYNC_INTERRUPT) {
1529	# async::interrupt	1635	# async::interrupt
1530
1531	$signal = sig2num $signal;	1636	my $signal = sig2num $arg{signal};
1532	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1637	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1533		1638
1534	$SIG_ASY{$signal} ||= new Async::Interrupt	1639	$SIG_ASY{$signal} ||= new Async::Interrupt
1535	cb => sub { undef $SIG_EV{$signal} },	1640	cb => sub { undef $SIG_EV{$signal} },
1536	signal => $signal,	1641	signal => $signal,
1537	pipe => [$SIGPIPE_R->filenos],	1642	pipe => [$SIGPIPE_R->filenos],
1538	pipe_autodrain => 0,	1643	pipe_autodrain => 0,
1539	;	1644	;
1540		1645
1541	} else {	1646	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1647	}
		1648	: sub {
		1649	my (undef, %arg) = @_;
		1650
1542	# pure perl	1651	# pure perl
1543
1544	# AE::Util has been loaded in signal
1545	$signal = sig2name $signal;	1652	my $signal = sig2name $arg{signal};
1546	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1653	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1547		1654
1548	$SIG{$signal} ||= sub {	1655	$SIG{$signal} ||= sub {
1549	local $!;	1656	local $!;
1550	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1657	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1551	undef $SIG_EV{$signal};	1658	undef $SIG_EV{$signal};
1552	};	1659	};
1553		1660
1554	# can't do signal processing without introducing races in pure perl,	1661	# can't do signal processing without introducing races in pure perl,
1555	# so limit the signal latency.	1662	# so limit the signal latency.
1556	_sig_add;	1663	_sig_add;
1557	}
1558		1664
1559	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1665	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1666	}
1560	};	1667	;
1561		1668
1562	*AnyEvent::Base::signal::DESTROY = sub {	1669	*AnyEvent::Base::signal::DESTROY = sub {
1563	my ($signal, $cb) = @{$_[0]};	1670	my ($signal, $cb) = @{$_[0]};
1564		1671
1565	_sig_del;	1672	_sig_del;
…		…
1572	# print weird messages, or just unconditionally exit	1679	# print weird messages, or just unconditionally exit
1573	# instead of getting the default action.	1680	# instead of getting the default action.
1574	undef $SIG{$signal}	1681	undef $SIG{$signal}
1575	unless keys %{ $SIG_CB{$signal} };	1682	unless keys %{ $SIG_CB{$signal} };
1576	};	1683	};
		1684
		1685	*_signal_exec = sub {
		1686	$HAVE_ASYNC_INTERRUPT
		1687	? $SIGPIPE_R->drain
		1688	: sysread $SIGPIPE_R, (my $dummy), 9;
		1689
		1690	while (%SIG_EV) {
		1691	for (keys %SIG_EV) {
		1692	delete $SIG_EV{$_};
		1693	&$_ for values %{ $SIG_CB{$_} || {} };
		1694	}
		1695	}
		1696	};
1577	};	1697	};
1578	die if $@;	1698	die if $@;
		1699
1579	&signal	1700	&signal
1580	}	1701	}
1581		1702
1582	# default implementation for ->child	1703	# default implementation for ->child
1583		1704
1584	our %PID_CB;	1705	our %PID_CB;
1585	our $CHLD_W;	1706	our $CHLD_W;
1586	our $CHLD_DELAY_W;	1707	our $CHLD_DELAY_W;
1587	our $WNOHANG;
1588		1708
		1709	# used by many Impl's
1589	sub _emit_childstatus($$) {	1710	sub _emit_childstatus($$) {
1590	my (undef, $rpid, $rstatus) = @_;	1711	my (undef, $rpid, $rstatus) = @_;
1591		1712
1592	$_->($rpid, $rstatus)	1713	$_->($rpid, $rstatus)
1593	for values %{ $PID_CB{$rpid} || {} },	1714	for values %{ $PID_CB{$rpid} || {} },
1594	values %{ $PID_CB{0} || {} };	1715	values %{ $PID_CB{0} || {} };
1595	}	1716	}
1596		1717
1597	sub _sigchld {
1598	my $pid;
1599
1600	AnyEvent->_emit_childstatus ($pid, $?)
1601	while ($pid = waitpid -1, $WNOHANG) > 0;
1602	}
1603
1604	sub child {	1718	sub child {
		1719	eval q{ # poor man's autoloading {}
		1720	*_sigchld = sub {
		1721	my $pid;
		1722
		1723	AnyEvent->_emit_childstatus ($pid, $?)
		1724	while ($pid = waitpid -1, WNOHANG) > 0;
		1725	};
		1726
		1727	*child = sub {
1605	my (undef, %arg) = @_;	1728	my (undef, %arg) = @_;
1606		1729
1607	defined (my $pid = $arg{pid} + 0)	1730	my $pid = $arg{pid};
1608	or Carp::croak "required option 'pid' is missing";	1731	my $cb = $arg{cb};
1609		1732
1610	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1733	$PID_CB{$pid}{$cb+0} = $cb;
1611		1734
1612	# WNOHANG is almost cetrainly 1 everywhere
1613	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1614	? 1
1615	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1616
1617	unless ($CHLD_W) {	1735	unless ($CHLD_W) {
1618	$CHLD_W = AE::signal CHLD => \&_sigchld;	1736	$CHLD_W = AE::signal CHLD => \&_sigchld;
1619	# child could be a zombie already, so make at least one round	1737	# child could be a zombie already, so make at least one round
1620	&_sigchld;	1738	&_sigchld;
1621	}	1739	}
1622		1740
1623	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1741	bless [$pid, $cb+0], "AnyEvent::Base::child"
1624	}	1742	};
1625		1743
1626	sub AnyEvent::Base::child::DESTROY {	1744	*AnyEvent::Base::child::DESTROY = sub {
1627	my ($pid, $cb) = @{$_[0]};	1745	my ($pid, $icb) = @{$_[0]};
1628		1746
1629	delete $PID_CB{$pid}{$cb};	1747	delete $PID_CB{$pid}{$icb};
1630	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1748	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1631		1749
1632	undef $CHLD_W unless keys %PID_CB;	1750	undef $CHLD_W unless keys %PID_CB;
		1751	};
		1752	};
		1753	die if $@;
		1754
		1755	&child
1633	}	1756	}
1634		1757
1635	# idle emulation is done by simply using a timer, regardless	1758	# idle emulation is done by simply using a timer, regardless
1636	# of whether the process is idle or not, and not letting	1759	# of whether the process is idle or not, and not letting
1637	# the callback use more than 50% of the time.	1760	# the callback use more than 50% of the time.
1638	sub idle {	1761	sub idle {
		1762	eval q{ # poor man's autoloading {}
		1763	*idle = sub {
1639	my (undef, %arg) = @_;	1764	my (undef, %arg) = @_;
1640		1765
1641	my ($cb, $w, $rcb) = $arg{cb};	1766	my ($cb, $w, $rcb) = $arg{cb};
1642		1767
1643	$rcb = sub {	1768	$rcb = sub {
1644	if ($cb) {	1769	if ($cb) {
1645	$w = _time;	1770	$w = AE::time;
1646	&$cb;	1771	&$cb;
1647	$w = _time - $w;	1772	$w = AE::time - $w;
1648		1773
1649	# never use more then 50% of the time for the idle watcher,	1774	# never use more then 50% of the time for the idle watcher,
1650	# within some limits	1775	# within some limits
1651	$w = 0.0001 if $w < 0.0001;	1776	$w = 0.0001 if $w < 0.0001;
1652	$w = 5 if $w > 5;	1777	$w = 5 if $w > 5;
1653		1778
1654	$w = AE::timer $w, 0, $rcb;	1779	$w = AE::timer $w, 0, $rcb;
1655	} else {	1780	} else {
1656	# clean up...	1781	# clean up...
1657	undef $w;	1782	undef $w;
1658	undef $rcb;	1783	undef $rcb;
		1784	}
		1785	};
		1786
		1787	$w = AE::timer 0.05, 0, $rcb;
		1788
		1789	bless \\$cb, "AnyEvent::Base::idle"
1659	}	1790	};
		1791
		1792	*AnyEvent::Base::idle::DESTROY = sub {
		1793	undef $${$_[0]};
		1794	};
1660	};	1795	};
		1796	die if $@;
1661		1797
1662	$w = AE::timer 0.05, 0, $rcb;	1798	&idle
1663
1664	bless \\$cb, "AnyEvent::Base::idle"
1665	}
1666
1667	sub AnyEvent::Base::idle::DESTROY {
1668	undef $${$_[0]};
1669	}	1799	}
1670		1800
1671	package AnyEvent::CondVar;	1801	package AnyEvent::CondVar;
1672		1802
1673	our @ISA = AnyEvent::CondVar::Base::;	1803	our @ISA = AnyEvent::CondVar::Base::;
		1804
		1805	# only to be used for subclassing
		1806	sub new {
		1807	my $class = shift;
		1808	bless AnyEvent->condvar (@_), $class
		1809	}
1674		1810
1675	package AnyEvent::CondVar::Base;	1811	package AnyEvent::CondVar::Base;
1676		1812
1677	#use overload	1813	#use overload
1678	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1814	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
…		…
1688		1824
1689	sub _send {	1825	sub _send {
1690	# nop	1826	# nop
1691	}	1827	}
1692		1828
		1829	sub _wait {
		1830	AnyEvent->_poll until $_[0]{_ae_sent};
		1831	}
		1832
1693	sub send {	1833	sub send {
1694	my $cv = shift;	1834	my $cv = shift;
1695	$cv->{_ae_sent} = [@_];	1835	$cv->{_ae_sent} = [@_];
1696	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};	1836	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1697	$cv->_send;	1837	$cv->_send;
…		…
1704		1844
1705	sub ready {	1845	sub ready {
1706	$_[0]{_ae_sent}	1846	$_[0]{_ae_sent}
1707	}	1847	}
1708		1848
1709	sub _wait {
1710	$WAITING
1711	and !$_[0]{_ae_sent}
1712	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1713
1714	local $WAITING = 1;
1715	AnyEvent->one_event while !$_[0]{_ae_sent};
1716	}
1717
1718	sub recv {	1849	sub recv {
		1850	unless ($_[0]{_ae_sent}) {
		1851	$WAITING
		1852	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1853
		1854	local $WAITING = 1;
1719	$_[0]->_wait;	1855	$_[0]->_wait;
		1856	}
1720		1857
1721	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1858	$_[0]{_ae_croak}
1722	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1859	and Carp::croak $_[0]{_ae_croak};
		1860
		1861	wantarray
		1862	? @{ $_[0]{_ae_sent} }
		1863	: $_[0]{_ae_sent}[0]
1723	}	1864	}
1724		1865
1725	sub cb {	1866	sub cb {
1726	my $cv = shift;	1867	my $cv = shift;
1727		1868
…		…
1743	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	1884	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1744	}	1885	}
1745		1886
1746	# undocumented/compatibility with pre-3.4	1887	# undocumented/compatibility with pre-3.4
1747	*broadcast = \&send;	1888	*broadcast = \&send;
1748	*wait = \&_wait;	1889	*wait = \&recv;
1749		1890
1750	=head1 ERROR AND EXCEPTION HANDLING	1891	=head1 ERROR AND EXCEPTION HANDLING
1751		1892
1752	In general, AnyEvent does not do any error handling - it relies on the	1893	In general, AnyEvent does not do any error handling - it relies on the
1753	caller to do that if required. The L<AnyEvent::Strict> module (see also	1894	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1800	check the arguments passed to most method calls. If it finds any problems,	1941	check the arguments passed to most method calls. If it finds any problems,
1801	it will croak.	1942	it will croak.
1802		1943
1803	In other words, enables "strict" mode.	1944	In other words, enables "strict" mode.
1804		1945
1805	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	1946	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1806	>>, it is definitely recommended to keep it off in production. Keeping	1947	>>, it is definitely recommended to keep it off in production. Keeping
1807	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	1948	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1808	can be very useful, however.	1949	can be very useful, however.
1809		1950
1810	=item C<PERL_ANYEVENT_MODEL>	1951	=item C<PERL_ANYEVENT_MODEL>
1811		1952
1812	This can be used to specify the event model to be used by AnyEvent, before	1953	This can be used to specify the event model to be used by AnyEvent, before
1813	auto detection and -probing kicks in. It must be a string consisting	1954	auto detection and -probing kicks in.
1814	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1955
		1956	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		1957	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1815	and the resulting module name is loaded and if the load was successful,	1958	resulting module name is loaded and - if the load was successful - used as
1816	used as event model. If it fails to load AnyEvent will proceed with	1959	event model backend. If it fails to load then AnyEvent will proceed with
1817	auto detection and -probing.	1960	auto detection and -probing.
1818		1961
1819	This functionality might change in future versions.	1962	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		1963	nothing gets prepended and the module name is used as-is (hint: C<::> at
		1964	the end of a string designates a module name and quotes it appropriately).
1820		1965
1821	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1966	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1822	could start your program like this:	1967	could start your program like this:
1823		1968
1824	PERL_ANYEVENT_MODEL=Perl perl ...	1969	PERL_ANYEVENT_MODEL=Perl perl ...
1825		1970
1826	=item C<PERL_ANYEVENT_PROTOCOLS>	1971	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
2032		2177
2033	The actual code goes further and collects all errors (C<die>s, exceptions)	2178	The actual code goes further and collects all errors (C<die>s, exceptions)
2034	that occurred during request processing. The C<result> method detects	2179	that occurred during request processing. The C<result> method detects
2035	whether an exception as thrown (it is stored inside the $txn object)	2180	whether an exception as thrown (it is stored inside the $txn object)
2036	and just throws the exception, which means connection errors and other	2181	and just throws the exception, which means connection errors and other
2037	problems get reported tot he code that tries to use the result, not in a	2182	problems get reported to the code that tries to use the result, not in a
2038	random callback.	2183	random callback.
2039		2184
2040	All of this enables the following usage styles:	2185	All of this enables the following usage styles:
2041		2186
2042	1. Blocking:	2187	1. Blocking:
…		…
2456	unless defined $SIG{PIPE};	2601	unless defined $SIG{PIPE};
2457		2602
2458	=head1 RECOMMENDED/OPTIONAL MODULES	2603	=head1 RECOMMENDED/OPTIONAL MODULES
2459		2604
2460	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2605	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2461	it's built-in modules) are required to use it.	2606	its built-in modules) are required to use it.
2462		2607
2463	That does not mean that AnyEvent won't take advantage of some additional	2608	That does not mean that AnyEvent won't take advantage of some additional
2464	modules if they are installed.	2609	modules if they are installed.
2465		2610
2466	This section explains which additional modules will be used, and how they	2611	This section explains which additional modules will be used, and how they
…		…
2499	automatic timer adjustments even when no monotonic clock is available,	2644	automatic timer adjustments even when no monotonic clock is available,
2500	can take avdantage of advanced kernel interfaces such as C<epoll> and	2645	can take avdantage of advanced kernel interfaces such as C<epoll> and
2501	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2646	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2502	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2647	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2503		2648
		2649	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2650	then this module will do nothing for you.
		2651
2504	=item L<Guard>	2652	=item L<Guard>
2505		2653
2506	The guard module, when used, will be used to implement	2654	The guard module, when used, will be used to implement
2507	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2655	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2508	lot less memory), but otherwise doesn't affect guard operation much. It is	2656	lot less memory), but otherwise doesn't affect guard operation much. It is
2509	purely used for performance.	2657	purely used for performance.
2510		2658
2511	=item L<JSON> and L<JSON::XS>	2659	=item L<JSON> and L<JSON::XS>
2512		2660
2513	One of these modules is required when you want to read or write JSON data	2661	One of these modules is required when you want to read or write JSON data
2514	via L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2662	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2515	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.	2663	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2516
2517	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2518	installed.
2519		2664
2520	=item L<Net::SSLeay>	2665	=item L<Net::SSLeay>
2521		2666
2522	Implementing TLS/SSL in Perl is certainly interesting, but not very	2667	Implementing TLS/SSL in Perl is certainly interesting, but not very
2523	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2668	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2524	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2669	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2525		2670
2526	=item L<Time::HiRes>	2671	=item L<Time::HiRes>
2527		2672
2528	This module is part of perl since release 5.008. It will be used when the	2673	This module is part of perl since release 5.008. It will be used when the
2529	chosen event library does not come with a timing source on it's own. The	2674	chosen event library does not come with a timing source of its own. The
2530	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2675	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2531	try to use a monotonic clock for timing stability.	2676	try to use a monotonic clock for timing stability.
2532		2677
2533	=back	2678	=back
2534		2679
2535		2680
2536	=head1 FORK	2681	=head1 FORK
2537		2682
2538	Most event libraries are not fork-safe. The ones who are usually are	2683	Most event libraries are not fork-safe. The ones who are usually are
2539	because they rely on inefficient but fork-safe C<select> or C<poll>	2684	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2540	calls. Only L<EV> is fully fork-aware.	2685	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2686	are usually badly thought-out hacks that are incompatible with fork in
		2687	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2688	continue event-processing in both parent and child (or both, if you know
		2689	what you are doing).
2541		2690
2542	This means that, in general, you cannot fork and do event processing	2691	This means that, in general, you cannot fork and do event processing in
2543	in the child if a watcher was created before the fork (which in turn	2692	the child if the event library was initialised before the fork (which
2544	initialises the event library).	2693	usually happens when the first AnyEvent watcher is created, or the library
		2694	is loaded).
2545		2695
2546	If you have to fork, you must either do so I<before> creating your first	2696	If you have to fork, you must either do so I<before> creating your first
2547	watcher OR you must not use AnyEvent at all in the child OR you must do	2697	watcher OR you must not use AnyEvent at all in the child OR you must do
2548	something completely out of the scope of AnyEvent.	2698	something completely out of the scope of AnyEvent.
2549		2699
2550	The problem of doing event processing in the parent I<and> the child	2700	The problem of doing event processing in the parent I<and> the child
2551	is much more complicated: even for backends that I<are> fork-aware or	2701	is much more complicated: even for backends that I<are> fork-aware or
2552	fork-safe, their behaviour is not usually what you want: fork clones all	2702	fork-safe, their behaviour is not usually what you want: fork clones all
2553	watchers, that means all timers, I/O watchers etc. are active in both	2703	watchers, that means all timers, I/O watchers etc. are active in both
2554	parent and child, which is almost never what you want.	2704	parent and child, which is almost never what you want. USing C<exec>
		2705	to start worker children from some kind of manage rprocess is usually
		2706	preferred, because it is much easier and cleaner, at the expense of having
		2707	to have another binary.
2555		2708
2556		2709
2557	=head1 SECURITY CONSIDERATIONS	2710	=head1 SECURITY CONSIDERATIONS
2558		2711
2559	AnyEvent can be forced to load any event model via	2712	AnyEvent can be forced to load any event model via
…		…
2589	pronounced).	2742	pronounced).
2590		2743
2591		2744
2592	=head1 SEE ALSO	2745	=head1 SEE ALSO
2593		2746
		2747	Tutorial/Introduction: L<AnyEvent::Intro>.
		2748
		2749	FAQ: L<AnyEvent::FAQ>.
		2750
2594	Utility functions: L<AnyEvent::Util>.	2751	Utility functions: L<AnyEvent::Util>.
2595		2752
2596	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2753	Event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>, L<Glib::EV>,
2597	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2754	L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2598		2755
2599	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2756	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2600	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2757	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2601	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2758	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2602	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.	2759	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
…		…
2604	Non-blocking file handles, sockets, TCP clients and	2761	Non-blocking file handles, sockets, TCP clients and
2605	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2762	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2606		2763
2607	Asynchronous DNS: L<AnyEvent::DNS>.	2764	Asynchronous DNS: L<AnyEvent::DNS>.
2608		2765
2609	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	2766	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2610	L<Coro::Event>,
2611		2767
2612	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	2768	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2613	L<AnyEvent::HTTP>.	2769	L<AnyEvent::HTTP>.
2614		2770
2615		2771
2616	=head1 AUTHOR	2772	=head1 AUTHOR
2617		2773

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