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Revision 1.273 by root, Thu Aug 6 13:45:04 2009 UTC vs.
Revision 1.331 by root, Tue Aug 31 01:00:48 2010 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
…		…
73	module users into the same thing by forcing them to use the same event	76	module users into the same thing by forcing them to use the same event
74	model you use.	77	model you use.
75		78
76	For modules like POE or IO::Async (which is a total misnomer as it is	79	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	80	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	81	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	82	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	83	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.	84	module are I<also> forced to use the same event loop you use.
82		85
83	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	86	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
84	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	87	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	88	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
86	your module uses one of those, every user of your module has to use it,	89	your module uses one of those, every user of your module has to use it,
87	too. But if your module uses AnyEvent, it works transparently with all	90	too. But if your module uses AnyEvent, it works transparently with all
88	event models it supports (including stuff like IO::Async, as long as those	91	event models it supports (including stuff like IO::Async, as long as those
89	use one of the supported event loops. It is trivial to add new event loops	92	use one of the supported event loops. It is easy to add new event loops
90	to AnyEvent, too, so it is future-proof).	93	to AnyEvent, too, so it is future-proof).
91		94
92	In addition to being free of having to use I<the one and only true event	95	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	96	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	97	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	98	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	99	offering the functionality that is necessary, in as thin as a wrapper as
97	technically possible.	100	technically possible.
98		101
99	Of course, AnyEvent comes with a big (and fully optional!) toolbox	102	Of course, AnyEvent comes with a big (and fully optional!) toolbox
100	of useful functionality, such as an asynchronous DNS resolver, 100%	103	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	109	useful) and you want to force your users to use the one and only event
107	model, you should I<not> use this module.	110	model, you should I<not> use this module.
108		111
109	=head1 DESCRIPTION	112	=head1 DESCRIPTION
110		113
111	L<AnyEvent> provides an identical interface to multiple event loops. This	114	L<AnyEvent> provides a uniform interface to various event loops. This
112	allows module authors to utilise an event loop without forcing module	115	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	116	module users to use a specific event loop implementation (since more
114	peacefully at any one time).	117	than one event loop cannot coexist peacefully).
115		118
116	The interface itself is vaguely similar, but not identical to the L<Event>	119	The interface itself is vaguely similar, but not identical to the L<Event>
117	module.	120	module.
118		121
119	During the first call of any watcher-creation method, the module tries	122	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	123	to detect the currently loaded event loop by probing whether one of the
121	following modules is already loaded: L<EV>,	124	following modules is already loaded: L<EV>, L<AnyEvent::Impl::Perl>,
122	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	125	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	126	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	127	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	128	available, the pure-perl L<AnyEvent::Impl::Perl> should always work, so
126	be successfully loaded will be used. If, after this, still none could be	129	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		130
130	Because AnyEvent first checks for modules that are already loaded, loading	131	Because AnyEvent first checks for modules that are already loaded, loading
131	an event model explicitly before first using AnyEvent will likely make	132	an event model explicitly before first using AnyEvent will likely make
132	that model the default. For example:	133	that model the default. For example:
133		134
…		…
135	use AnyEvent;	136	use AnyEvent;
136		137
137	# .. AnyEvent will likely default to Tk	138	# .. AnyEvent will likely default to Tk
138		139
139	The I<likely> means that, if any module loads another event model and	140	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	141	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...	142	as very few modules hardcode event loops without announcing this very
		143	loudly.
142		144
143	The pure-perl implementation of AnyEvent is called	145	The pure-perl implementation of AnyEvent is called
144	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	146	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
145	explicitly and enjoy the high availability of that event loop :)	147	explicitly and enjoy the high availability of that event loop :)
146		148
…		…
155	callback when the event occurs (of course, only when the event model	157	callback when the event occurs (of course, only when the event model
156	is in control).	158	is in control).
157		159
158	Note that B<callbacks must not permanently change global variables>	160	Note that B<callbacks must not permanently change global variables>
159	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<	161	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
160	callbacks must not C<die> >>. The former is good programming practise in	162	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	163	Perl and the latter stems from the fact that exception handling differs
162	widely between event loops.	164	widely between event loops.
163		165
164	To disable the watcher you have to destroy it (e.g. by setting the	166	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	167	variable you store it in to C<undef> or otherwise deleting all references
166	to it).	168	to it).
167		169
168	All watchers are created by calling a method on the C<AnyEvent> class.	170	All watchers are created by calling a method on the C<AnyEvent> class.
169		171
170	Many watchers either are used with "recursion" (repeating timers for	172	Many watchers either are used with "recursion" (repeating timers for
171	example), or need to refer to their watcher object in other ways.	173	example), or need to refer to their watcher object in other ways.
172		174
173	An any way to achieve that is this pattern:	175	One way to achieve that is this pattern:
174		176
175	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	177	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
176	# you can use $w here, for example to undef it	178	# you can use $w here, for example to undef it
177	undef $w;	179	undef $w;
178	});	180	});
…		…
210		212
211	The I/O watcher might use the underlying file descriptor or a copy of it.	213	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	214	You must not close a file handle as long as any watcher is active on the
213	underlying file descriptor.	215	underlying file descriptor.
214		216
215	Some event loops issue spurious readyness notifications, so you should	217	Some event loops issue spurious readiness notifications, so you should
216	always use non-blocking calls when reading/writing from/to your file	218	always use non-blocking calls when reading/writing from/to your file
217	handles.	219	handles.
218		220
219	Example: wait for readability of STDIN, then read a line and disable the	221	Example: wait for readability of STDIN, then read a line and disable the
220	watcher.	222	watcher.
…		…
244		246
245	Although the callback might get passed parameters, their value and	247	Although the callback might get passed parameters, their value and
246	presence is undefined and you cannot rely on them. Portable AnyEvent	248	presence is undefined and you cannot rely on them. Portable AnyEvent
247	callbacks cannot use arguments passed to time watcher callbacks.	249	callbacks cannot use arguments passed to time watcher callbacks.
248		250
249	The callback will normally be invoked once only. If you specify another	251	The callback will normally be invoked only once. If you specify another
250	parameter, C<interval>, as a strictly positive number (> 0), then the	252	parameter, C<interval>, as a strictly positive number (> 0), then the
251	callback will be invoked regularly at that interval (in fractional	253	callback will be invoked regularly at that interval (in fractional
252	seconds) after the first invocation. If C<interval> is specified with a	254	seconds) after the first invocation. If C<interval> is specified with a
253	false value, then it is treated as if it were missing.	255	false value, then it is treated as if it were not specified at all.
254		256
255	The callback will be rescheduled before invoking the callback, but no	257	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	258	attempt is made to avoid timer drift in most backends, so the interval is
257	only approximate.	259	only approximate.
258		260
259	Example: fire an event after 7.7 seconds.	261	Example: fire an event after 7.7 seconds.
260		262
261	my $w = AnyEvent->timer (after => 7.7, cb => sub {	263	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
279		281
280	While most event loops expect timers to specified in a relative way, they	282	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	283	use absolute time internally. This makes a difference when your clock
282	"jumps", for example, when ntp decides to set your clock backwards from	284	"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	285	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.	286	fire "after a second" might actually take six years to finally fire.
285		287
286	AnyEvent cannot compensate for this. The only event loop that is conscious	288	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	289	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)	290	on true relative time) and absolute (ev_periodic, based on wallclock time)
289	timers.	291	timers.
290		292
291	AnyEvent always prefers relative timers, if available, matching the	293	AnyEvent always prefers relative timers, if available, matching the
292	AnyEvent API.	294	AnyEvent API.
…		…
314	I<In almost all cases (in all cases if you don't care), this is the	316	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.>	317	function to call when you want to know the current time.>
316		318
317	This function is also often faster then C<< AnyEvent->time >>, and	319	This function is also often faster then C<< AnyEvent->time >>, and
318	thus the preferred method if you want some timestamp (for example,	320	thus the preferred method if you want some timestamp (for example,
319	L<AnyEvent::Handle> uses this to update it's activity timeouts).	321	L<AnyEvent::Handle> uses this to update its activity timeouts).
320		322
321	The rest of this section is only of relevance if you try to be very exact	323	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.	324	with your timing; you can skip it without a bad conscience.
323		325
324	For a practical example of when these times differ, consider L<Event::Lib>	326	For a practical example of when these times differ, consider L<Event::Lib>
325	and L<EV> and the following set-up:	327	and L<EV> and the following set-up:
326		328
327	The event loop is running and has just invoked one of your callback at	329	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,	330	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	331	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	332	second) and then (at time=501) you create a relative timer that fires
331	after three seconds.	333	after three seconds.
332		334
…		…
363	might affect timers and time-outs.	365	might affect timers and time-outs.
364		366
365	When this is the case, you can call this method, which will update the	367	When this is the case, you can call this method, which will update the
366	event loop's idea of "current time".	368	event loop's idea of "current time".
367		369
		370	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		371	when mod_perl executes the script, then the event loop will have the wrong
		372	idea about the "current time" (being potentially far in the past, when the
		373	script ran the last time). In that case you should arrange a call to C<<
		374	AnyEvent->now_update >> each time the web server process wakes up again
		375	(e.g. at the start of your script, or in a handler).
		376
368	Note that updating the time I<might> cause some events to be handled.	377	Note that updating the time I<might> cause some events to be handled.
369		378
370	=back	379	=back
371		380
372	=head2 SIGNAL WATCHERS	381	=head2 SIGNAL WATCHERS
…		…
396		405
397	Example: exit on SIGINT	406	Example: exit on SIGINT
398		407
399	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	408	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
400		409
		410	=head3 Restart Behaviour
		411
		412	While restart behaviour is up to the event loop implementation, most will
		413	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		414	pure perl implementation).
		415
		416	=head3 Safe/Unsafe Signals
		417
		418	Perl signals can be either "safe" (synchronous to opcode handling) or
		419	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		420	latter might corrupt your memory.
		421
		422	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		423	i.e. they will not interrupt your running perl program but will only be
		424	called as part of the normal event handling (just like timer, I/O etc.
		425	callbacks, too).
		426
401	=head3 Signal Races, Delays and Workarounds	427	=head3 Signal Races, Delays and Workarounds
402		428
403	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching	429	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
404	callbacks to signals in a generic way, which is a pity, as you cannot	430	callbacks to signals in a generic way, which is a pity, as you cannot
405	do race-free signal handling in perl, requiring C libraries for	431	do race-free signal handling in perl, requiring C libraries for
406	this. AnyEvent will try to do it's best, which means in some cases,	432	this. AnyEvent will try to do its best, which means in some cases,
407	signals will be delayed. The maximum time a signal might be delayed is	433	signals will be delayed. The maximum time a signal might be delayed is
408	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This	434	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
409	variable can be changed only before the first signal watcher is created,	435	variable can be changed only before the first signal watcher is created,
410	and should be left alone otherwise. This variable determines how often	436	and should be left alone otherwise. This variable determines how often
411	AnyEvent polls for signals (in case a wake-up was missed). Higher values	437	AnyEvent polls for signals (in case a wake-up was missed). Higher values
…		…
413	saving.	439	saving.
414		440
415	All these problems can be avoided by installing the optional	441	All these problems can be avoided by installing the optional
416	L<Async::Interrupt> module, which works with most event loops. It will not	442	L<Async::Interrupt> module, which works with most event loops. It will not
417	work with inherently broken event loops such as L<Event> or L<Event::Lib>	443	work with inherently broken event loops such as L<Event> or L<Event::Lib>
418	(and not with L<POE> currently, as POE does it's own workaround with	444	(and not with L<POE> currently, as POE does its own workaround with
419	one-second latency). For those, you just have to suffer the delays.	445	one-second latency). For those, you just have to suffer the delays.
420		446
421	=head2 CHILD PROCESS WATCHERS	447	=head2 CHILD PROCESS WATCHERS
422		448
423	$w = AnyEvent->child (pid => <process id>, cb => <callback>);	449	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
424		450
425	You can also watch on a child process exit and catch its exit status.	451	You can also watch for a child process exit and catch its exit status.
426		452
427	The child process is specified by the C<pid> argument (one some backends,	453	The child process is specified by the C<pid> argument (on some backends,
428	using C<0> watches for any child process exit, on others this will	454	using C<0> watches for any child process exit, on others this will
429	croak). The watcher will be triggered only when the child process has	455	croak). The watcher will be triggered only when the child process has
430	finished and an exit status is available, not on any trace events	456	finished and an exit status is available, not on any trace events
431	(stopped/continued).	457	(stopped/continued).
432		458
…		…
479		505
480	=head2 IDLE WATCHERS	506	=head2 IDLE WATCHERS
481		507
482	$w = AnyEvent->idle (cb => <callback>);	508	$w = AnyEvent->idle (cb => <callback>);
483		509
484	Sometimes there is a need to do something, but it is not so important	510	This will repeatedly invoke the callback after the process becomes idle,
485	to do it instantly, but only when there is nothing better to do. This	511	until either the watcher is destroyed or new events have been detected.
486	"nothing better to do" is usually defined to be "no other events need
487	attention by the event loop".
488		512
489	Idle watchers ideally get invoked when the event loop has nothing	513	Idle watchers are useful when there is a need to do something, but it
490	better to do, just before it would block the process to wait for new	514	is not so important (or wise) to do it instantly. The callback will be
491	events. Instead of blocking, the idle watcher is invoked.	515	invoked only when there is "nothing better to do", which is usually
		516	defined as "all outstanding events have been handled and no new events
		517	have been detected". That means that idle watchers ideally get invoked
		518	when the event loop has just polled for new events but none have been
		519	detected. Instead of blocking to wait for more events, the idle watchers
		520	will be invoked.
492		521
493	Most event loops unfortunately do not really support idle watchers (only	522	Unfortunately, most event loops do not really support idle watchers (only
494	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	523	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
495	will simply call the callback "from time to time".	524	will simply call the callback "from time to time".
496		525
497	Example: read lines from STDIN, but only process them when the	526	Example: read lines from STDIN, but only process them when the
498	program is otherwise idle:	527	program is otherwise idle:
…		…
526	will actively watch for new events and call your callbacks.	555	will actively watch for new events and call your callbacks.
527		556
528	AnyEvent is slightly different: it expects somebody else to run the event	557	AnyEvent is slightly different: it expects somebody else to run the event
529	loop and will only block when necessary (usually when told by the user).	558	loop and will only block when necessary (usually when told by the user).
530		559
531	The instrument to do that is called a "condition variable", so called	560	The tool to do that is called a "condition variable", so called because
532	because they represent a condition that must become true.	561	they represent a condition that must become true.
533		562
534	Now is probably a good time to look at the examples further below.	563	Now is probably a good time to look at the examples further below.
535		564
536	Condition variables can be created by calling the C<< AnyEvent->condvar	565	Condition variables can be created by calling the C<< AnyEvent->condvar
537	>> method, usually without arguments. The only argument pair allowed is	566	>> method, usually without arguments. The only argument pair allowed is
…		…
542	After creation, the condition variable is "false" until it becomes "true"	571	After creation, the condition variable is "false" until it becomes "true"
543	by calling the C<send> method (or calling the condition variable as if it	572	by calling the C<send> method (or calling the condition variable as if it
544	were a callback, read about the caveats in the description for the C<<	573	were a callback, read about the caveats in the description for the C<<
545	->send >> method).	574	->send >> method).
546		575
547	Condition variables are similar to callbacks, except that you can	576	Since condition variables are the most complex part of the AnyEvent API, here are
548	optionally wait for them. They can also be called merge points - points	577	some different mental models of what they are - pick the ones you can connect to:
549	in time where multiple outstanding events have been processed. And yet	578
550	another way to call them is transactions - each condition variable can be	579	=over 4
551	used to represent a transaction, which finishes at some point and delivers	580
552	a result. And yet some people know them as "futures" - a promise to	581	=item * Condition variables are like callbacks - you can call them (and pass them instead
553	compute/deliver something that you can wait for.	582	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		583
		584	=item * Condition variables are signals - one side can emit or send them,
		585	the other side can wait for them, or install a handler that is called when
		586	the signal fires.
		587
		588	=item * Condition variables are like "Merge Points" - points in your program
		589	where you merge multiple independent results/control flows into one.
		590
		591	=item * Condition variables represent a transaction - functions that start
		592	some kind of transaction can return them, leaving the caller the choice
		593	between waiting in a blocking fashion, or setting a callback.
		594
		595	=item * Condition variables represent future values, or promises to deliver
		596	some result, long before the result is available.
		597
		598	=back
554		599
555	Condition variables are very useful to signal that something has finished,	600	Condition variables are very useful to signal that something has finished,
556	for example, if you write a module that does asynchronous http requests,	601	for example, if you write a module that does asynchronous http requests,
557	then a condition variable would be the ideal candidate to signal the	602	then a condition variable would be the ideal candidate to signal the
558	availability of results. The user can either act when the callback is	603	availability of results. The user can either act when the callback is
…		…
571		616
572	Condition variables are represented by hash refs in perl, and the keys	617	Condition variables are represented by hash refs in perl, and the keys
573	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing	618	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
574	easy (it is often useful to build your own transaction class on top of	619	easy (it is often useful to build your own transaction class on top of
575	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call	620	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
576	it's C<new> method in your own C<new> method.	621	its C<new> method in your own C<new> method.
577		622
578	There are two "sides" to a condition variable - the "producer side" which	623	There are two "sides" to a condition variable - the "producer side" which
579	eventually calls C<< -> send >>, and the "consumer side", which waits	624	eventually calls C<< -> send >>, and the "consumer side", which waits
580	for the send to occur.	625	for the send to occur.
581		626
582	Example: wait for a timer.	627	Example: wait for a timer.
583		628
584	# wait till the result is ready	629	# condition: "wait till the timer is fired"
585	my $result_ready = AnyEvent->condvar;	630	my $timer_fired = AnyEvent->condvar;
586		631
587	# do something such as adding a timer	632	# create the timer - we could wait for, say
588	# or socket watcher the calls $result_ready->send	633	# a handle becomign ready, or even an
589	# when the "result" is ready.	634	# AnyEvent::HTTP request to finish, but
590	# in this case, we simply use a timer:	635	# in this case, we simply use a timer:
591	my $w = AnyEvent->timer (	636	my $w = AnyEvent->timer (
592	after => 1,	637	after => 1,
593	cb => sub { $result_ready->send },	638	cb => sub { $timer_fired->send },
594	);	639	);
595		640
596	# this "blocks" (while handling events) till the callback	641	# this "blocks" (while handling events) till the callback
597	# calls -<send	642	# calls ->send
598	$result_ready->recv;	643	$timer_fired->recv;
599		644
600	Example: wait for a timer, but take advantage of the fact that condition	645	Example: wait for a timer, but take advantage of the fact that condition
601	variables are also callable directly.	646	variables are also callable directly.
602		647
603	my $done = AnyEvent->condvar;	648	my $done = AnyEvent->condvar;
…		…
646	they were a code reference). Calling them directly is the same as calling	691	they were a code reference). Calling them directly is the same as calling
647	C<send>.	692	C<send>.
648		693
649	=item $cv->croak ($error)	694	=item $cv->croak ($error)
650		695
651	Similar to send, but causes all call's to C<< ->recv >> to invoke	696	Similar to send, but causes all calls to C<< ->recv >> to invoke
652	C<Carp::croak> with the given error message/object/scalar.	697	C<Carp::croak> with the given error message/object/scalar.
653		698
654	This can be used to signal any errors to the condition variable	699	This can be used to signal any errors to the condition variable
655	user/consumer. Doing it this way instead of calling C<croak> directly	700	user/consumer. Doing it this way instead of calling C<croak> directly
656	delays the error detetcion, but has the overwhelmign advantage that it	701	delays the error detection, but has the overwhelming advantage that it
657	diagnoses the error at the place where the result is expected, and not	702	diagnoses the error at the place where the result is expected, and not
658	deep in some event clalback without connection to the actual code causing	703	deep in some event callback with no connection to the actual code causing
659	the problem.	704	the problem.
660		705
661	=item $cv->begin ([group callback])	706	=item $cv->begin ([group callback])
662		707
663	=item $cv->end	708	=item $cv->end
…		…
666	one. For example, a function that pings many hosts in parallel might want	711	one. For example, a function that pings many hosts in parallel might want
667	to use a condition variable for the whole process.	712	to use a condition variable for the whole process.
668		713
669	Every call to C<< ->begin >> will increment a counter, and every call to	714	Every call to C<< ->begin >> will increment a counter, and every call to
670	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	715	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
671	>>, the (last) callback passed to C<begin> will be executed. That callback	716	>>, the (last) callback passed to C<begin> will be executed, passing the
672	is I<supposed> to call C<< ->send >>, but that is not required. If no	717	condvar as first argument. That callback is I<supposed> to call C<< ->send
673	callback was set, C<send> will be called without any arguments.	718	>>, but that is not required. If no group callback was set, C<send> will
		719	be called without any arguments.
674		720
675	You can think of C<< $cv->send >> giving you an OR condition (one call	721	You can think of C<< $cv->send >> giving you an OR condition (one call
676	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND	722	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
677	condition (all C<begin> calls must be C<end>'ed before the condvar sends).	723	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
678		724
…		…
700	one call to C<begin>, so the condvar waits for all calls to C<end> before	746	one call to C<begin>, so the condvar waits for all calls to C<end> before
701	sending.	747	sending.
702		748
703	The ping example mentioned above is slightly more complicated, as the	749	The ping example mentioned above is slightly more complicated, as the
704	there are results to be passwd back, and the number of tasks that are	750	there are results to be passwd back, and the number of tasks that are
705	begung can potentially be zero:	751	begun can potentially be zero:
706		752
707	my $cv = AnyEvent->condvar;	753	my $cv = AnyEvent->condvar;
708		754
709	my %result;	755	my %result;
710	$cv->begin (sub { $cv->send (\%result) });	756	$cv->begin (sub { shift->send (\%result) });
711		757
712	for my $host (@list_of_hosts) {	758	for my $host (@list_of_hosts) {
713	$cv->begin;	759	$cv->begin;
714	ping_host_then_call_callback $host, sub {	760	ping_host_then_call_callback $host, sub {
715	$result{$host} = ...;	761	$result{$host} = ...;
…		…
731	to be called once the counter reaches C<0>, and second, it ensures that	777	to be called once the counter reaches C<0>, and second, it ensures that
732	C<send> is called even when C<no> hosts are being pinged (the loop	778	C<send> is called even when C<no> hosts are being pinged (the loop
733	doesn't execute once).	779	doesn't execute once).
734		780
735	This is the general pattern when you "fan out" into multiple (but	781	This is the general pattern when you "fan out" into multiple (but
736	potentially none) subrequests: use an outer C<begin>/C<end> pair to set	782	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
737	the callback and ensure C<end> is called at least once, and then, for each	783	the callback and ensure C<end> is called at least once, and then, for each
738	subrequest you start, call C<begin> and for each subrequest you finish,	784	subrequest you start, call C<begin> and for each subrequest you finish,
739	call C<end>.	785	call C<end>.
740		786
741	=back	787	=back
…		…
748	=over 4	794	=over 4
749		795
750	=item $cv->recv	796	=item $cv->recv
751		797
752	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	798	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
753	>> methods have been called on c<$cv>, while servicing other watchers	799	>> methods have been called on C<$cv>, while servicing other watchers
754	normally.	800	normally.
755		801
756	You can only wait once on a condition - additional calls are valid but	802	You can only wait once on a condition - additional calls are valid but
757	will return immediately.	803	will return immediately.
758		804
…		…
775	caller decide whether the call will block or not (for example, by coupling	821	caller decide whether the call will block or not (for example, by coupling
776	condition variables with some kind of request results and supporting	822	condition variables with some kind of request results and supporting
777	callbacks so the caller knows that getting the result will not block,	823	callbacks so the caller knows that getting the result will not block,
778	while still supporting blocking waits if the caller so desires).	824	while still supporting blocking waits if the caller so desires).
779		825
780	You can ensure that C<< -recv >> never blocks by setting a callback and	826	You can ensure that C<< ->recv >> never blocks by setting a callback and
781	only calling C<< ->recv >> from within that callback (or at a later	827	only calling C<< ->recv >> from within that callback (or at a later
782	time). This will work even when the event loop does not support blocking	828	time). This will work even when the event loop does not support blocking
783	waits otherwise.	829	waits otherwise.
784		830
785	=item $bool = $cv->ready	831	=item $bool = $cv->ready
…		…
790	=item $cb = $cv->cb ($cb->($cv))	836	=item $cb = $cv->cb ($cb->($cv))
791		837
792	This is a mutator function that returns the callback set and optionally	838	This is a mutator function that returns the callback set and optionally
793	replaces it before doing so.	839	replaces it before doing so.
794		840
795	The callback will be called when the condition becomes (or already was)	841	The callback will be called when the condition becomes "true", i.e. when
796	"true", i.e. when C<send> or C<croak> are called (or were called), with	842	C<send> or C<croak> are called, with the only argument being the
797	the only argument being the condition variable itself. Calling C<recv>	843	condition variable itself. If the condition is already true, the
		844	callback is called immediately when it is set. Calling C<recv> inside
798	inside the callback or at any later time is guaranteed not to block.	845	the callback or at any later time is guaranteed not to block.
799		846
800	=back	847	=back
801		848
802	=head1 SUPPORTED EVENT LOOPS/BACKENDS	849	=head1 SUPPORTED EVENT LOOPS/BACKENDS
803		850
…		…
806	=over 4	853	=over 4
807		854
808	=item Backends that are autoprobed when no other event loop can be found.	855	=item Backends that are autoprobed when no other event loop can be found.
809		856
810	EV is the preferred backend when no other event loop seems to be in	857	EV is the preferred backend when no other event loop seems to be in
811	use. If EV is not installed, then AnyEvent will try Event, and, failing	858	use. If EV is not installed, then AnyEvent will fall back to its own
812	that, will fall back to its own pure-perl implementation, which is	859	pure-perl implementation, which is available everywhere as it comes with
813	available everywhere as it comes with AnyEvent itself.	860	AnyEvent itself.
814		861
815	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	862	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
816	AnyEvent::Impl::Event based on Event, very stable, few glitches.
817	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	863	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
818		864
819	=item Backends that are transparently being picked up when they are used.	865	=item Backends that are transparently being picked up when they are used.
820		866
821	These will be used when they are currently loaded when the first watcher	867	These will be used if they are already loaded when the first watcher
822	is created, in which case it is assumed that the application is using	868	is created, in which case it is assumed that the application is using
823	them. This means that AnyEvent will automatically pick the right backend	869	them. This means that AnyEvent will automatically pick the right backend
824	when the main program loads an event module before anything starts to	870	when the main program loads an event module before anything starts to
825	create watchers. Nothing special needs to be done by the main program.	871	create watchers. Nothing special needs to be done by the main program.
826		872
		873	AnyEvent::Impl::Event based on Event, very stable, few glitches.
827	AnyEvent::Impl::Glib based on Glib, slow but very stable.	874	AnyEvent::Impl::Glib based on Glib, slow but very stable.
828	AnyEvent::Impl::Tk based on Tk, very broken.	875	AnyEvent::Impl::Tk based on Tk, very broken.
829	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	876	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
830	AnyEvent::Impl::POE based on POE, very slow, some limitations.	877	AnyEvent::Impl::POE based on POE, very slow, some limitations.
831	AnyEvent::Impl::Irssi used when running within irssi.	878	AnyEvent::Impl::Irssi used when running within irssi.
…		…
841		888
842	Support for IO::Async can only be partial, as it is too broken and	889	Support for IO::Async can only be partial, as it is too broken and
843	architecturally limited to even support the AnyEvent API. It also	890	architecturally limited to even support the AnyEvent API. It also
844	is the only event loop that needs the loop to be set explicitly, so	891	is the only event loop that needs the loop to be set explicitly, so
845	it can only be used by a main program knowing about AnyEvent. See	892	it can only be used by a main program knowing about AnyEvent. See
846	L<AnyEvent::Impl::Async> for the gory details.	893	L<AnyEvent::Impl::IOAsync> for the gory details.
847		894
848	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.	895	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
849		896
850	=item Event loops that are indirectly supported via other backends.	897	=item Event loops that are indirectly supported via other backends.
851		898
…		…
879	Contains C<undef> until the first watcher is being created, before the	926	Contains C<undef> until the first watcher is being created, before the
880	backend has been autodetected.	927	backend has been autodetected.
881		928
882	Afterwards it contains the event model that is being used, which is the	929	Afterwards it contains the event model that is being used, which is the
883	name of the Perl class implementing the model. This class is usually one	930	name of the Perl class implementing the model. This class is usually one
884	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the	931	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
885	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it	932	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
886	will be C<urxvt::anyevent>).	933	will be C<urxvt::anyevent>).
887		934
888	=item AnyEvent::detect	935	=item AnyEvent::detect
889		936
890	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	937	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
891	if necessary. You should only call this function right before you would	938	if necessary. You should only call this function right before you would
892	have created an AnyEvent watcher anyway, that is, as late as possible at	939	have created an AnyEvent watcher anyway, that is, as late as possible at
893	runtime, and not e.g. while initialising of your module.	940	runtime, and not e.g. during initialisation of your module.
894		941
895	If you need to do some initialisation before AnyEvent watchers are	942	If you need to do some initialisation before AnyEvent watchers are
896	created, use C<post_detect>.	943	created, use C<post_detect>.
897		944
898	=item $guard = AnyEvent::post_detect { BLOCK }	945	=item $guard = AnyEvent::post_detect { BLOCK }
899		946
900	Arranges for the code block to be executed as soon as the event model is	947	Arranges for the code block to be executed as soon as the event model is
901	autodetected (or immediately if this has already happened).	948	autodetected (or immediately if that has already happened).
902		949
903	The block will be executed I<after> the actual backend has been detected	950	The block will be executed I<after> the actual backend has been detected
904	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	951	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
905	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	952	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
906	other initialisations - see the sources of L<AnyEvent::Strict> or	953	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
915	that automatically removes the callback again when it is destroyed (or	962	that automatically removes the callback again when it is destroyed (or
916	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for	963	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
917	a case where this is useful.	964	a case where this is useful.
918		965
919	Example: Create a watcher for the IO::AIO module and store it in	966	Example: Create a watcher for the IO::AIO module and store it in
920	C<$WATCHER>. Only do so after the event loop is initialised, though.	967	C<$WATCHER>, but do so only do so after the event loop is initialised.
921		968
922	our WATCHER;	969	our WATCHER;
923		970
924	my $guard = AnyEvent::post_detect {	971	my $guard = AnyEvent::post_detect {
925	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);	972	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
…		…
933	$WATCHER ||= $guard;	980	$WATCHER ||= $guard;
934		981
935	=item @AnyEvent::post_detect	982	=item @AnyEvent::post_detect
936		983
937	If there are any code references in this array (you can C<push> to it	984	If there are any code references in this array (you can C<push> to it
938	before or after loading AnyEvent), then they will called directly after	985	before or after loading AnyEvent), then they will be called directly
939	the event loop has been chosen.	986	after the event loop has been chosen.
940		987
941	You should check C<$AnyEvent::MODEL> before adding to this array, though:	988	You should check C<$AnyEvent::MODEL> before adding to this array, though:
942	if it is defined then the event loop has already been detected, and the	989	if it is defined then the event loop has already been detected, and the
943	array will be ignored.	990	array will be ignored.
944		991
945	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	992	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
946	it,as it takes care of these details.	993	it, as it takes care of these details.
947		994
948	This variable is mainly useful for modules that can do something useful	995	This variable is mainly useful for modules that can do something useful
949	when AnyEvent is used and thus want to know when it is initialised, but do	996	when AnyEvent is used and thus want to know when it is initialised, but do
950	not need to even load it by default. This array provides the means to hook	997	not need to even load it by default. This array provides the means to hook
951	into AnyEvent passively, without loading it.	998	into AnyEvent passively, without loading it.
952		999
		1000	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1001	together, you could put this into Coro (this is the actual code used by
		1002	Coro to accomplish this):
		1003
		1004	if (defined $AnyEvent::MODEL) {
		1005	# AnyEvent already initialised, so load Coro::AnyEvent
		1006	require Coro::AnyEvent;
		1007	} else {
		1008	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1009	# as soon as it is
		1010	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1011	}
		1012
953	=back	1013	=back
954		1014
955	=head1 WHAT TO DO IN A MODULE	1015	=head1 WHAT TO DO IN A MODULE
956		1016
957	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1017	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
967	because it will stall the whole program, and the whole point of using	1027	because it will stall the whole program, and the whole point of using
968	events is to stay interactive.	1028	events is to stay interactive.
969		1029
970	It is fine, however, to call C<< ->recv >> when the user of your module	1030	It is fine, however, to call C<< ->recv >> when the user of your module
971	requests it (i.e. if you create a http request object ad have a method	1031	requests it (i.e. if you create a http request object ad have a method
972	called C<results> that returns the results, it should call C<< ->recv >>	1032	called C<results> that returns the results, it may call C<< ->recv >>
973	freely, as the user of your module knows what she is doing. always).	1033	freely, as the user of your module knows what she is doing. Always).
974		1034
975	=head1 WHAT TO DO IN THE MAIN PROGRAM	1035	=head1 WHAT TO DO IN THE MAIN PROGRAM
976		1036
977	There will always be a single main program - the only place that should	1037	There will always be a single main program - the only place that should
978	dictate which event model to use.	1038	dictate which event model to use.
979		1039
980	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1040	If the program is not event-based, it need not do anything special, even
981	do anything special (it does not need to be event-based) and let AnyEvent	1041	when it depends on a module that uses an AnyEvent. If the program itself
982	decide which implementation to chose if some module relies on it.	1042	uses AnyEvent, but does not care which event loop is used, all it needs
		1043	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1044	available loop implementation.
983		1045
984	If the main program relies on a specific event model - for example, in	1046	If the main program relies on a specific event model - for example, in
985	Gtk2 programs you have to rely on the Glib module - you should load the	1047	Gtk2 programs you have to rely on the Glib module - you should load the
986	event module before loading AnyEvent or any module that uses it: generally	1048	event module before loading AnyEvent or any module that uses it: generally
987	speaking, you should load it as early as possible. The reason is that	1049	speaking, you should load it as early as possible. The reason is that
988	modules might create watchers when they are loaded, and AnyEvent will	1050	modules might create watchers when they are loaded, and AnyEvent will
989	decide on the event model to use as soon as it creates watchers, and it	1051	decide on the event model to use as soon as it creates watchers, and it
990	might chose the wrong one unless you load the correct one yourself.	1052	might choose the wrong one unless you load the correct one yourself.
991		1053
992	You can chose to use a pure-perl implementation by loading the	1054	You can chose to use a pure-perl implementation by loading the
993	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1055	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
994	everywhere, but letting AnyEvent chose the model is generally better.	1056	everywhere, but letting AnyEvent chose the model is generally better.
995		1057
…		…
1013	=head1 OTHER MODULES	1075	=head1 OTHER MODULES
1014		1076
1015	The following is a non-exhaustive list of additional modules that use	1077	The following is a non-exhaustive list of additional modules that use
1016	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1078	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
1017	modules and other event loops in the same program. Some of the modules	1079	modules and other event loops in the same program. Some of the modules
1018	come with AnyEvent, most are available via CPAN.	1080	come as part of AnyEvent, the others are available via CPAN.
1019		1081
1020	=over 4	1082	=over 4
1021		1083
1022	=item L<AnyEvent::Util>	1084	=item L<AnyEvent::Util>
1023		1085
1024	Contains various utility functions that replace often-used but blocking	1086	Contains various utility functions that replace often-used blocking
1025	functions such as C<inet_aton> by event-/callback-based versions.	1087	functions such as C<inet_aton> with event/callback-based versions.
1026		1088
1027	=item L<AnyEvent::Socket>	1089	=item L<AnyEvent::Socket>
1028		1090
1029	Provides various utility functions for (internet protocol) sockets,	1091	Provides various utility functions for (internet protocol) sockets,
1030	addresses and name resolution. Also functions to create non-blocking tcp	1092	addresses and name resolution. Also functions to create non-blocking tcp
…		…
1032		1094
1033	=item L<AnyEvent::Handle>	1095	=item L<AnyEvent::Handle>
1034		1096
1035	Provide read and write buffers, manages watchers for reads and writes,	1097	Provide read and write buffers, manages watchers for reads and writes,
1036	supports raw and formatted I/O, I/O queued and fully transparent and	1098	supports raw and formatted I/O, I/O queued and fully transparent and
1037	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1099	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1038		1100
1039	=item L<AnyEvent::DNS>	1101	=item L<AnyEvent::DNS>
1040		1102
1041	Provides rich asynchronous DNS resolver capabilities.	1103	Provides rich asynchronous DNS resolver capabilities.
1042		1104
		1105	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1106
		1107	Implement event-based interfaces to the protocols of the same name (for
		1108	the curious, IGS is the International Go Server and FCP is the Freenet
		1109	Client Protocol).
		1110
		1111	=item L<AnyEvent::Handle::UDP>
		1112
		1113	Here be danger!
		1114
		1115	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1116	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1117	its use of a stream-based API with a protocol that isn't streamable, that
		1118	the only way to improve it is to delete it.
		1119
		1120	It features data corruption (but typically only under load) and general
		1121	confusion. On top, the author is not only clueless about UDP but also
		1122	fact-resistant - some gems of his understanding: "connect doesn't work
		1123	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1124	packets", "I don't need to implement proper error checking as UDP doesn't
		1125	support error checking" and so on - he doesn't even understand what's
		1126	wrong with his module when it is explained to him.
		1127
1043	=item L<AnyEvent::HTTP>	1128	=item L<AnyEvent::DBI>
1044		1129
1045	A simple-to-use HTTP library that is capable of making a lot of concurrent	1130	Executes L<DBI> requests asynchronously in a proxy process for you,
1046	HTTP requests.	1131	notifying you in an event-based way when the operation is finished.
		1132
		1133	=item L<AnyEvent::AIO>
		1134
		1135	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1136	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1137	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1138	file I/O, and much more.
1047		1139
1048	=item L<AnyEvent::HTTPD>	1140	=item L<AnyEvent::HTTPD>
1049		1141
1050	Provides a simple web application server framework.	1142	A simple embedded webserver.
1051		1143
1052	=item L<AnyEvent::FastPing>	1144	=item L<AnyEvent::FastPing>
1053		1145
1054	The fastest ping in the west.	1146	The fastest ping in the west.
1055
1056	=item L<AnyEvent::DBI>
1057
1058	Executes L<DBI> requests asynchronously in a proxy process.
1059
1060	=item L<AnyEvent::AIO>
1061
1062	Truly asynchronous I/O, should be in the toolbox of every event
1063	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1064	together.
1065
1066	=item L<AnyEvent::BDB>
1067
1068	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1069	L<BDB> and AnyEvent together.
1070
1071	=item L<AnyEvent::GPSD>
1072
1073	A non-blocking interface to gpsd, a daemon delivering GPS information.
1074
1075	=item L<AnyEvent::IRC>
1076
1077	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1078
1079	=item L<AnyEvent::XMPP>
1080
1081	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1082	Net::XMPP2>.
1083
1084	=item L<AnyEvent::IGS>
1085
1086	A non-blocking interface to the Internet Go Server protocol (used by
1087	L<App::IGS>).
1088
1089	=item L<Net::FCP>
1090
1091	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1092	of AnyEvent.
1093
1094	=item L<Event::ExecFlow>
1095
1096	High level API for event-based execution flow control.
1097		1147
1098	=item L<Coro>	1148	=item L<Coro>
1099		1149
1100	Has special support for AnyEvent via L<Coro::AnyEvent>.	1150	Has special support for AnyEvent via L<Coro::AnyEvent>.
1101		1151
…		…
1105		1155
1106	package AnyEvent;	1156	package AnyEvent;
1107		1157
1108	# basically a tuned-down version of common::sense	1158	# basically a tuned-down version of common::sense
1109	sub common_sense {	1159	sub common_sense {
1110	# no warnings	1160	# from common:.sense 1.0
1111	${^WARNING_BITS} ^= ${^WARNING_BITS};	1161	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
1112	# use strict vars subs	1162	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1113	$^H |= 0x00000600;	1163	$^H |= 0x00000600;
1114	}	1164	}
1115		1165
1116	BEGIN { AnyEvent::common_sense }	1166	BEGIN { AnyEvent::common_sense }
1117		1167
1118	use Carp ();	1168	use Carp ();
1119		1169
1120	our $VERSION = 4.91;	1170	our $VERSION = '5.271';
1121	our $MODEL;	1171	our $MODEL;
1122		1172
1123	our $AUTOLOAD;	1173	our $AUTOLOAD;
1124	our @ISA;	1174	our @ISA;
1125		1175
1126	our @REGISTRY;	1176	our @REGISTRY;
1127		1177
1128	our $WIN32;
1129
1130	our $VERBOSE;	1178	our $VERBOSE;
1131		1179
1132	BEGIN {	1180	BEGIN {
1133	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1181	require "AnyEvent/constants.pl";
		1182
1134	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1183	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1135		1184
1136	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1185	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1137	if ${^TAINT};	1186	if ${^TAINT};
1138		1187
1139	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1188	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
…		…
1151	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1200	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1152	}	1201	}
1153		1202
1154	my @models = (	1203	my @models = (
1155	[EV:: => AnyEvent::Impl::EV:: , 1],	1204	[EV:: => AnyEvent::Impl::EV:: , 1],
1156	[Event:: => AnyEvent::Impl::Event::, 1],
1157	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],	1205	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1158	# everything below here will not (normally) be autoprobed	1206	# everything below here will not (normally) be autoprobed
1159	# as the pureperl backend should work everywhere	1207	# as the pureperl backend should work everywhere
1160	# and is usually faster	1208	# and is usually faster
		1209	[Event:: => AnyEvent::Impl::Event::, 1],
1161	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers	1210	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1162	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1211	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1163	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package	1212	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1164	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1213	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1165	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1214	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
…		…
1168	[Prima:: => AnyEvent::Impl::POE::],	1217	[Prima:: => AnyEvent::Impl::POE::],
1169	# IO::Async is just too broken - we would need workarounds for its	1218	# IO::Async is just too broken - we would need workarounds for its
1170	# byzantine signal and broken child handling, among others.	1219	# byzantine signal and broken child handling, among others.
1171	# IO::Async is rather hard to detect, as it doesn't have any	1220	# IO::Async is rather hard to detect, as it doesn't have any
1172	# obvious default class.	1221	# obvious default class.
1173	# [0, IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program	1222	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1174	# [0, IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program	1223	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1175	# [0, IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program	1224	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1225	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1176	);	1226	);
1177		1227
1178	our %method = map +($_ => 1),	1228	our %method = map +($_ => 1),
1179	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1229	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
1180		1230
1181	our @post_detect;	1231	our @post_detect;
1182		1232
1183	sub post_detect(&) {	1233	sub post_detect(&) {
1184	my ($cb) = @_;	1234	my ($cb) = @_;
1185		1235
1186	if ($MODEL) {
1187	$cb->();
1188
1189	undef
1190	} else {
1191	push @post_detect, $cb;	1236	push @post_detect, $cb;
1192		1237
1193	defined wantarray	1238	defined wantarray
1194	? bless \$cb, "AnyEvent::Util::postdetect"	1239	? bless \$cb, "AnyEvent::Util::postdetect"
1195	: ()	1240	: ()
1196	}
1197	}	1241	}
1198		1242
1199	sub AnyEvent::Util::postdetect::DESTROY {	1243	sub AnyEvent::Util::postdetect::DESTROY {
1200	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1244	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1201	}	1245	}
1202		1246
1203	sub detect() {	1247	sub detect() {
		1248	# free some memory
		1249	*detect = sub () { $MODEL };
		1250
		1251	local $!; # for good measure
		1252	local $SIG{__DIE__};
		1253
		1254	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1255	my $model = "AnyEvent::Impl::$1";
		1256	if (eval "require $model") {
		1257	$MODEL = $model;
		1258	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1259	} else {
		1260	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1261	}
		1262	}
		1263
		1264	# check for already loaded models
1204	unless ($MODEL) {	1265	unless ($MODEL) {
1205	local $SIG{__DIE__};	1266	for (@REGISTRY, @models) {
1206		1267	my ($package, $model) = @$_;
1207	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1268	if (${"$package\::VERSION"} > 0) {
1208	my $model = "AnyEvent::Impl::$1";
1209	if (eval "require $model") {	1269	if (eval "require $model") {
1210	$MODEL = $model;	1270	$MODEL = $model;
1211	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1271	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1212	} else {	1272	last;
1213	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1273	}
1214	}	1274	}
1215	}	1275	}
1216		1276
1217	# check for already loaded models
1218	unless ($MODEL) {	1277	unless ($MODEL) {
		1278	# try to autoload a model
1219	for (@REGISTRY, @models) {	1279	for (@REGISTRY, @models) {
1220	my ($package, $model) = @$_;	1280	my ($package, $model, $autoload) = @$_;
		1281	if (
		1282	$autoload
		1283	and eval "require $package"
1221	if (${"$package\::VERSION"} > 0) {	1284	and ${"$package\::VERSION"} > 0
1222	if (eval "require $model") {	1285	and eval "require $model"
		1286	) {
1223	$MODEL = $model;	1287	$MODEL = $model;
1224	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;	1288	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1225	last;	1289	last;
1226	}
1227	}	1290	}
1228	}	1291	}
1229		1292
1230	unless ($MODEL) {
1231	# try to autoload a model
1232	for (@REGISTRY, @models) {
1233	my ($package, $model, $autoload) = @$_;
1234	if (
1235	$autoload
1236	and eval "require $package"
1237	and ${"$package\::VERSION"} > 0
1238	and eval "require $model"
1239	) {
1240	$MODEL = $model;
1241	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1242	last;
1243	}
1244	}
1245
1246	$MODEL	1293	$MODEL
1247	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1294	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
1248	}
1249	}	1295	}
1250
1251	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1252
1253	unshift @ISA, $MODEL;
1254
1255	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1256
1257	(shift @post_detect)->() while @post_detect;
1258	}	1296	}
		1297
		1298	@models = (); # free probe data
		1299
		1300	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1301	unshift @ISA, $MODEL;
		1302
		1303	# now nuke some methods that are overriden by the backend.
		1304	# SUPER is not allowed.
		1305	for (qw(time signal child idle)) {
		1306	undef &{"AnyEvent::Base::$_"}
		1307	if defined &{"$MODEL\::$_"};
		1308	}
		1309
		1310	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1311
		1312	(shift @post_detect)->() while @post_detect;
		1313
		1314	*post_detect = sub(&) {
		1315	shift->();
		1316
		1317	undef
		1318	};
1259		1319
1260	$MODEL	1320	$MODEL
1261	}	1321	}
1262		1322
1263	sub AUTOLOAD {	1323	sub AUTOLOAD {
1264	(my $func = $AUTOLOAD) =~ s/.*://;	1324	(my $func = $AUTOLOAD) =~ s/.*://;
1265		1325
1266	$method{$func}	1326	$method{$func}
1267	or Carp::croak "$func: not a valid method for AnyEvent objects";	1327	or Carp::croak "$func: not a valid AnyEvent class method";
1268		1328
1269	detect unless $MODEL;	1329	detect;
1270		1330
1271	my $class = shift;	1331	my $class = shift;
1272	$class->$func (@_);	1332	$class->$func (@_);
1273	}	1333	}
1274		1334
…		…
1287	# we assume CLOEXEC is already set by perl in all important cases	1347	# we assume CLOEXEC is already set by perl in all important cases
1288		1348
1289	($fh2, $rw)	1349	($fh2, $rw)
1290	}	1350	}
1291		1351
1292	#############################################################################	1352	=head1 SIMPLIFIED AE API
1293	# "new" API, currently only emulation of it	1353
1294	#############################################################################	1354	Starting with version 5.0, AnyEvent officially supports a second, much
		1355	simpler, API that is designed to reduce the calling, typing and memory
		1356	overhead by using function call syntax and a fixed number of parameters.
		1357
		1358	See the L<AE> manpage for details.
		1359
		1360	=cut
1295		1361
1296	package AE;	1362	package AE;
		1363
		1364	our $VERSION = $AnyEvent::VERSION;
		1365
		1366	# fall back to the main API by default - backends and AnyEvent::Base
		1367	# implementations can overwrite these.
1297		1368
1298	sub io($$$) {	1369	sub io($$$) {
1299	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])	1370	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1300	}	1371	}
1301		1372
1302	sub timer($$$) {	1373	sub timer($$$) {
1303	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2]);	1374	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1304	}	1375	}
1305		1376
1306	sub signal($$) {	1377	sub signal($$) {
1307	AnyEvent->signal (signal => $_[0], cb => $_[1]);	1378	AnyEvent->signal (signal => $_[0], cb => $_[1])
1308	}	1379	}
1309		1380
1310	sub child($$) {	1381	sub child($$) {
1311	AnyEvent->child (pid => $_[0], cb => $_[1]);	1382	AnyEvent->child (pid => $_[0], cb => $_[1])
1312	}	1383	}
1313		1384
1314	sub idle($) {	1385	sub idle($) {
1315	AnyEvent->idle (cb => $_[0]);	1386	AnyEvent->idle (cb => $_[0])
1316	}	1387	}
1317		1388
1318	sub cv(;&) {	1389	sub cv(;&) {
1319	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())	1390	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1320	}	1391	}
…		…
1333		1404
1334	package AnyEvent::Base;	1405	package AnyEvent::Base;
1335		1406
1336	# default implementations for many methods	1407	# default implementations for many methods
1337		1408
1338	sub _time {	1409	sub time {
		1410	eval q{ # poor man's autoloading {}
1339	# probe for availability of Time::HiRes	1411	# probe for availability of Time::HiRes
1340	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1412	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1341	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1413	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1342	*_time = \&Time::HiRes::time;	1414	*AE::time = \&Time::HiRes::time;
1343	# if (eval "use POSIX (); (POSIX::times())...	1415	# if (eval "use POSIX (); (POSIX::times())...
1344	} else {	1416	} else {
1345	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1417	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1346	*_time = sub { time }; # epic fail	1418	*AE::time = sub (){ time }; # epic fail
		1419	}
		1420
		1421	*time = sub { AE::time }; # different prototypes
1347	}	1422	};
		1423	die if $@;
1348		1424
1349	&_time	1425	&time
1350	}	1426	}
1351		1427
1352	sub time { _time }	1428	*now = \&time;
1353	sub now { _time }	1429
1354	sub now_update { }	1430	sub now_update { }
1355		1431
1356	# default implementation for ->condvar	1432	# default implementation for ->condvar
1357		1433
1358	sub condvar {	1434	sub condvar {
		1435	eval q{ # poor man's autoloading {}
		1436	*condvar = sub {
1359	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1437	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1438	};
		1439
		1440	*AE::cv = sub (;&) {
		1441	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1442	};
		1443	};
		1444	die if $@;
		1445
		1446	&condvar
1360	}	1447	}
1361		1448
1362	# default implementation for ->signal	1449	# default implementation for ->signal
1363		1450
1364	our $HAVE_ASYNC_INTERRUPT;	1451	our $HAVE_ASYNC_INTERRUPT;
1365		1452
1366	sub _have_async_interrupt() {	1453	sub _have_async_interrupt() {
1367	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}	1454	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
1368	&& eval "use Async::Interrupt 1.0 (); 1")	1455	&& eval "use Async::Interrupt 1.02 (); 1")
1369	unless defined $HAVE_ASYNC_INTERRUPT;	1456	unless defined $HAVE_ASYNC_INTERRUPT;
1370		1457
1371	$HAVE_ASYNC_INTERRUPT	1458	$HAVE_ASYNC_INTERRUPT
1372	}	1459	}
1373		1460
1374	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1461	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1375	our (%SIG_ASY, %SIG_ASY_W);	1462	our (%SIG_ASY, %SIG_ASY_W);
1376	our ($SIG_COUNT, $SIG_TW);	1463	our ($SIG_COUNT, $SIG_TW);
1377		1464
1378	sub _signal_exec {
1379	$HAVE_ASYNC_INTERRUPT
1380	? $SIGPIPE_R->drain
1381	: sysread $SIGPIPE_R, my $dummy, 9;
1382
1383	while (%SIG_EV) {
1384	for (keys %SIG_EV) {
1385	delete $SIG_EV{$_};
1386	$_->() for values %{ $SIG_CB{$_} || {} };
1387	}
1388	}
1389	}
1390
1391	# install a dummy wakeup watcher to reduce signal catching latency	1465	# install a dummy wakeup watcher to reduce signal catching latency
		1466	# used by Impls
1392	sub _sig_add() {	1467	sub _sig_add() {
1393	unless ($SIG_COUNT++) {	1468	unless ($SIG_COUNT++) {
1394	# try to align timer on a full-second boundary, if possible	1469	# try to align timer on a full-second boundary, if possible
1395	my $NOW = AE::now;	1470	my $NOW = AE::now;
1396		1471
…		…
1406	undef $SIG_TW	1481	undef $SIG_TW
1407	unless --$SIG_COUNT;	1482	unless --$SIG_COUNT;
1408	}	1483	}
1409		1484
1410	our $_sig_name_init; $_sig_name_init = sub {	1485	our $_sig_name_init; $_sig_name_init = sub {
1411	eval q{ # poor man's autoloading	1486	eval q{ # poor man's autoloading {}
1412	undef $_sig_name_init;	1487	undef $_sig_name_init;
1413		1488
1414	if (_have_async_interrupt) {	1489	if (_have_async_interrupt) {
1415	*sig2num = \&Async::Interrupt::sig2num;	1490	*sig2num = \&Async::Interrupt::sig2num;
1416	*sig2name = \&Async::Interrupt::sig2name;	1491	*sig2name = \&Async::Interrupt::sig2name;
…		…
1448	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;	1523	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1449		1524
1450	} else {	1525	} else {
1451	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;	1526	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1452		1527
1453	require Fcntl;
1454
1455	if (AnyEvent::WIN32) {	1528	if (AnyEvent::WIN32) {
1456	require AnyEvent::Util;	1529	require AnyEvent::Util;
1457		1530
1458	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();	1531	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1459	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;	1532	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1460	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case	1533	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1461	} else {	1534	} else {
1462	pipe $SIGPIPE_R, $SIGPIPE_W;	1535	pipe $SIGPIPE_R, $SIGPIPE_W;
1463	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1536	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1464	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1537	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1465		1538
1466	# not strictly required, as $^F is normally 2, but let's make sure...	1539	# not strictly required, as $^F is normally 2, but let's make sure...
1467	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1540	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1468	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1541	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1469	}	1542	}
1470		1543
1471	$SIGPIPE_R	1544	$SIGPIPE_R
1472	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1545	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1473		1546
1474	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;	1547	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1475	}	1548	}
1476		1549
1477	*signal = sub {	1550	*signal = $HAVE_ASYNC_INTERRUPT
		1551	? sub {
1478	my (undef, %arg) = @_;	1552	my (undef, %arg) = @_;
1479		1553
1480	my $signal = uc $arg{signal}
1481	or Carp::croak "required option 'signal' is missing";
1482
1483	if ($HAVE_ASYNC_INTERRUPT) {
1484	# async::interrupt	1554	# async::interrupt
1485
1486	$signal = sig2num $signal;	1555	my $signal = sig2num $arg{signal};
1487	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1556	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1488		1557
1489	$SIG_ASY{$signal} ||= new Async::Interrupt	1558	$SIG_ASY{$signal} ||= new Async::Interrupt
1490	cb => sub { undef $SIG_EV{$signal} },	1559	cb => sub { undef $SIG_EV{$signal} },
1491	signal => $signal,	1560	signal => $signal,
1492	pipe => [$SIGPIPE_R->filenos],	1561	pipe => [$SIGPIPE_R->filenos],
1493	pipe_autodrain => 0,	1562	pipe_autodrain => 0,
1494	;	1563	;
1495		1564
1496	} else {	1565	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1566	}
		1567	: sub {
		1568	my (undef, %arg) = @_;
		1569
1497	# pure perl	1570	# pure perl
1498
1499	# AE::Util has been loaded in signal
1500	$signal = sig2name $signal;	1571	my $signal = sig2name $arg{signal};
1501	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1572	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1502		1573
1503	$SIG{$signal} ||= sub {	1574	$SIG{$signal} ||= sub {
1504	local $!;	1575	local $!;
1505	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1576	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1506	undef $SIG_EV{$signal};	1577	undef $SIG_EV{$signal};
1507	};	1578	};
1508		1579
1509	# can't do signal processing without introducing races in pure perl,	1580	# can't do signal processing without introducing races in pure perl,
1510	# so limit the signal latency.	1581	# so limit the signal latency.
1511	_sig_add;	1582	_sig_add;
1512	}
1513		1583
1514	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1584	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1585	}
1515	};	1586	;
1516		1587
1517	*AnyEvent::Base::signal::DESTROY = sub {	1588	*AnyEvent::Base::signal::DESTROY = sub {
1518	my ($signal, $cb) = @{$_[0]};	1589	my ($signal, $cb) = @{$_[0]};
1519		1590
1520	_sig_del;	1591	_sig_del;
…		…
1527	# print weird messages, or just unconditionally exit	1598	# print weird messages, or just unconditionally exit
1528	# instead of getting the default action.	1599	# instead of getting the default action.
1529	undef $SIG{$signal}	1600	undef $SIG{$signal}
1530	unless keys %{ $SIG_CB{$signal} };	1601	unless keys %{ $SIG_CB{$signal} };
1531	};	1602	};
		1603
		1604	*_signal_exec = sub {
		1605	$HAVE_ASYNC_INTERRUPT
		1606	? $SIGPIPE_R->drain
		1607	: sysread $SIGPIPE_R, (my $dummy), 9;
		1608
		1609	while (%SIG_EV) {
		1610	for (keys %SIG_EV) {
		1611	delete $SIG_EV{$_};
		1612	$_->() for values %{ $SIG_CB{$_} || {} };
		1613	}
		1614	}
		1615	};
1532	};	1616	};
1533	die if $@;	1617	die if $@;
		1618
1534	&signal	1619	&signal
1535	}	1620	}
1536		1621
1537	# default implementation for ->child	1622	# default implementation for ->child
1538		1623
1539	our %PID_CB;	1624	our %PID_CB;
1540	our $CHLD_W;	1625	our $CHLD_W;
1541	our $CHLD_DELAY_W;	1626	our $CHLD_DELAY_W;
1542	our $WNOHANG;	1627	our $WNOHANG;
1543		1628
		1629	# used by many Impl's
1544	sub _emit_childstatus($$) {	1630	sub _emit_childstatus($$) {
1545	my (undef, $rpid, $rstatus) = @_;	1631	my (undef, $rpid, $rstatus) = @_;
1546		1632
1547	$_->($rpid, $rstatus)	1633	$_->($rpid, $rstatus)
1548	for values %{ $PID_CB{$rpid} || {} },	1634	for values %{ $PID_CB{$rpid} || {} },
1549	values %{ $PID_CB{0} || {} };	1635	values %{ $PID_CB{0} || {} };
1550	}	1636	}
1551		1637
1552	sub _sigchld {
1553	my $pid;
1554
1555	AnyEvent->_emit_childstatus ($pid, $?)
1556	while ($pid = waitpid -1, $WNOHANG) > 0;
1557	}
1558
1559	sub child {	1638	sub child {
		1639	eval q{ # poor man's autoloading {}
		1640	*_sigchld = sub {
		1641	my $pid;
		1642
		1643	AnyEvent->_emit_childstatus ($pid, $?)
		1644	while ($pid = waitpid -1, $WNOHANG) > 0;
		1645	};
		1646
		1647	*child = sub {
1560	my (undef, %arg) = @_;	1648	my (undef, %arg) = @_;
1561		1649
1562	defined (my $pid = $arg{pid} + 0)	1650	defined (my $pid = $arg{pid} + 0)
1563	or Carp::croak "required option 'pid' is missing";	1651	or Carp::croak "required option 'pid' is missing";
1564		1652
1565	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1653	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1566		1654
1567	# WNOHANG is almost cetrainly 1 everywhere	1655	# WNOHANG is almost cetrainly 1 everywhere
1568	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/	1656	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1569	? 1	1657	? 1
1570	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1658	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1571		1659
1572	unless ($CHLD_W) {	1660	unless ($CHLD_W) {
1573	$CHLD_W = AE::signal CHLD => \&_sigchld;	1661	$CHLD_W = AE::signal CHLD => \&_sigchld;
1574	# child could be a zombie already, so make at least one round	1662	# child could be a zombie already, so make at least one round
1575	&_sigchld;	1663	&_sigchld;
1576	}	1664	}
1577		1665
1578	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1666	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1579	}	1667	};
1580		1668
1581	sub AnyEvent::Base::child::DESTROY {	1669	*AnyEvent::Base::child::DESTROY = sub {
1582	my ($pid, $cb) = @{$_[0]};	1670	my ($pid, $cb) = @{$_[0]};
1583		1671
1584	delete $PID_CB{$pid}{$cb};	1672	delete $PID_CB{$pid}{$cb};
1585	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1673	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1586		1674
1587	undef $CHLD_W unless keys %PID_CB;	1675	undef $CHLD_W unless keys %PID_CB;
		1676	};
		1677	};
		1678	die if $@;
		1679
		1680	&child
1588	}	1681	}
1589		1682
1590	# idle emulation is done by simply using a timer, regardless	1683	# idle emulation is done by simply using a timer, regardless
1591	# of whether the process is idle or not, and not letting	1684	# of whether the process is idle or not, and not letting
1592	# the callback use more than 50% of the time.	1685	# the callback use more than 50% of the time.
1593	sub idle {	1686	sub idle {
		1687	eval q{ # poor man's autoloading {}
		1688	*idle = sub {
1594	my (undef, %arg) = @_;	1689	my (undef, %arg) = @_;
1595		1690
1596	my ($cb, $w, $rcb) = $arg{cb};	1691	my ($cb, $w, $rcb) = $arg{cb};
1597		1692
1598	$rcb = sub {	1693	$rcb = sub {
1599	if ($cb) {	1694	if ($cb) {
1600	$w = _time;	1695	$w = _time;
1601	&$cb;	1696	&$cb;
1602	$w = _time - $w;	1697	$w = _time - $w;
1603		1698
1604	# never use more then 50% of the time for the idle watcher,	1699	# never use more then 50% of the time for the idle watcher,
1605	# within some limits	1700	# within some limits
1606	$w = 0.0001 if $w < 0.0001;	1701	$w = 0.0001 if $w < 0.0001;
1607	$w = 5 if $w > 5;	1702	$w = 5 if $w > 5;
1608		1703
1609	$w = AE::timer $w, 0, $rcb;	1704	$w = AE::timer $w, 0, $rcb;
1610	} else {	1705	} else {
1611	# clean up...	1706	# clean up...
1612	undef $w;	1707	undef $w;
1613	undef $rcb;	1708	undef $rcb;
		1709	}
		1710	};
		1711
		1712	$w = AE::timer 0.05, 0, $rcb;
		1713
		1714	bless \\$cb, "AnyEvent::Base::idle"
1614	}	1715	};
		1716
		1717	*AnyEvent::Base::idle::DESTROY = sub {
		1718	undef $${$_[0]};
		1719	};
1615	};	1720	};
		1721	die if $@;
1616		1722
1617	$w = AE::timer 0.05, 0, $rcb;	1723	&idle
1618
1619	bless \\$cb, "AnyEvent::Base::idle"
1620	}
1621
1622	sub AnyEvent::Base::idle::DESTROY {
1623	undef $${$_[0]};
1624	}	1724	}
1625		1725
1626	package AnyEvent::CondVar;	1726	package AnyEvent::CondVar;
1627		1727
1628	our @ISA = AnyEvent::CondVar::Base::;	1728	our @ISA = AnyEvent::CondVar::Base::;
…		…
1755	check the arguments passed to most method calls. If it finds any problems,	1855	check the arguments passed to most method calls. If it finds any problems,
1756	it will croak.	1856	it will croak.
1757		1857
1758	In other words, enables "strict" mode.	1858	In other words, enables "strict" mode.
1759		1859
1760	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	1860	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1761	>>, it is definitely recommended to keep it off in production. Keeping	1861	>>, it is definitely recommended to keep it off in production. Keeping
1762	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	1862	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1763	can be very useful, however.	1863	can be very useful, however.
1764		1864
1765	=item C<PERL_ANYEVENT_MODEL>	1865	=item C<PERL_ANYEVENT_MODEL>
…		…
1902	warn "read: $input\n"; # output what has been read	2002	warn "read: $input\n"; # output what has been read
1903	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2003	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1904	},	2004	},
1905	);	2005	);
1906		2006
1907	my $time_watcher; # can only be used once
1908
1909	sub new_timer {
1910	$timer = AnyEvent->timer (after => 1, cb => sub {	2007	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1911	warn "timeout\n"; # print 'timeout' about every second	2008	warn "timeout\n"; # print 'timeout' at most every second
1912	&new_timer; # and restart the time
1913	});	2009	});
1914	}
1915
1916	new_timer; # create first timer
1917		2010
1918	$cv->recv; # wait until user enters /^q/i	2011	$cv->recv; # wait until user enters /^q/i
1919		2012
1920	=head1 REAL-WORLD EXAMPLE	2013	=head1 REAL-WORLD EXAMPLE
1921		2014
…		…
1994		2087
1995	The actual code goes further and collects all errors (C<die>s, exceptions)	2088	The actual code goes further and collects all errors (C<die>s, exceptions)
1996	that occurred during request processing. The C<result> method detects	2089	that occurred during request processing. The C<result> method detects
1997	whether an exception as thrown (it is stored inside the $txn object)	2090	whether an exception as thrown (it is stored inside the $txn object)
1998	and just throws the exception, which means connection errors and other	2091	and just throws the exception, which means connection errors and other
1999	problems get reported tot he code that tries to use the result, not in a	2092	problems get reported to the code that tries to use the result, not in a
2000	random callback.	2093	random callback.
2001		2094
2002	All of this enables the following usage styles:	2095	All of this enables the following usage styles:
2003		2096
2004	1. Blocking:	2097	1. Blocking:
…		…
2052	through AnyEvent. The benchmark creates a lot of timers (with a zero	2145	through AnyEvent. The benchmark creates a lot of timers (with a zero
2053	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2146	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
2054	which it is), lets them fire exactly once and destroys them again.	2147	which it is), lets them fire exactly once and destroys them again.
2055		2148
2056	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2149	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
2057	distribution.	2150	distribution. It uses the L<AE> interface, which makes a real difference
		2151	for the EV and Perl backends only.
2058		2152
2059	=head3 Explanation of the columns	2153	=head3 Explanation of the columns
2060		2154
2061	I<watcher> is the number of event watchers created/destroyed. Since	2155	I<watcher> is the number of event watchers created/destroyed. Since
2062	different event models feature vastly different performances, each event	2156	different event models feature vastly different performances, each event
…		…
2083	watcher.	2177	watcher.
2084		2178
2085	=head3 Results	2179	=head3 Results
2086		2180
2087	name watchers bytes create invoke destroy comment	2181	name watchers bytes create invoke destroy comment
2088	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2182	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
2089	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2183	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
2090	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2184	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
2091	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2185	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
2092	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2186	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
2093	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2187	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
2094	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2188	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
2095	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2189	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
2096	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2190	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
2097	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2191	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
2098	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2192	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
2099	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2193	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
2100		2194
2101	=head3 Discussion	2195	=head3 Discussion
2102		2196
2103	The benchmark does I<not> measure scalability of the event loop very	2197	The benchmark does I<not> measure scalability of the event loop very
2104	well. For example, a select-based event loop (such as the pure perl one)	2198	well. For example, a select-based event loop (such as the pure perl one)
…		…
2116	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2210	benchmark machine, handling an event takes roughly 1600 CPU cycles with
2117	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2211	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
2118	cycles with POE.	2212	cycles with POE.
2119		2213
2120	C<EV> is the sole leader regarding speed and memory use, which are both	2214	C<EV> is the sole leader regarding speed and memory use, which are both
2121	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2215	maximal/minimal, respectively. When using the L<AE> API there is zero
		2216	overhead (when going through the AnyEvent API create is about 5-6 times
		2217	slower, with other times being equal, so still uses far less memory than
2122	far less memory than any other event loop and is still faster than Event	2218	any other event loop and is still faster than Event natively).
2123	natively.
2124		2219
2125	The pure perl implementation is hit in a few sweet spots (both the	2220	The pure perl implementation is hit in a few sweet spots (both the
2126	constant timeout and the use of a single fd hit optimisations in the perl	2221	constant timeout and the use of a single fd hit optimisations in the perl
2127	interpreter and the backend itself). Nevertheless this shows that it	2222	interpreter and the backend itself). Nevertheless this shows that it
2128	adds very little overhead in itself. Like any select-based backend its	2223	adds very little overhead in itself. Like any select-based backend its
…		…
2202	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2297	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2203	(1%) are active. This mirrors the activity of large servers with many	2298	(1%) are active. This mirrors the activity of large servers with many
2204	connections, most of which are idle at any one point in time.	2299	connections, most of which are idle at any one point in time.
2205		2300
2206	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2301	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2207	distribution.	2302	distribution. It uses the L<AE> interface, which makes a real difference
		2303	for the EV and Perl backends only.
2208		2304
2209	=head3 Explanation of the columns	2305	=head3 Explanation of the columns
2210		2306
2211	I<sockets> is the number of sockets, and twice the number of "servers" (as	2307	I<sockets> is the number of sockets, and twice the number of "servers" (as
2212	each server has a read and write socket end).	2308	each server has a read and write socket end).
…		…
2220	a new one that moves the timeout into the future.	2316	a new one that moves the timeout into the future.
2221		2317
2222	=head3 Results	2318	=head3 Results
2223		2319
2224	name sockets create request	2320	name sockets create request
2225	EV 20000 69.01 11.16	2321	EV 20000 62.66 7.99
2226	Perl 20000 73.32 35.87	2322	Perl 20000 68.32 32.64
2227	IOAsync 20000 157.00 98.14 epoll	2323	IOAsync 20000 174.06 101.15 epoll
2228	IOAsync 20000 159.31 616.06 poll	2324	IOAsync 20000 174.67 610.84 poll
2229	Event 20000 212.62 257.32	2325	Event 20000 202.69 242.91
2230	Glib 20000 651.16 1896.30	2326	Glib 20000 557.01 1689.52
2231	POE 20000 349.67 12317.24 uses POE::Loop::Event	2327	POE 20000 341.54 12086.32 uses POE::Loop::Event
2232		2328
2233	=head3 Discussion	2329	=head3 Discussion
2234		2330
2235	This benchmark I<does> measure scalability and overall performance of the	2331	This benchmark I<does> measure scalability and overall performance of the
2236	particular event loop.	2332	particular event loop.
…		…
2362	As you can see, the AnyEvent + EV combination even beats the	2458	As you can see, the AnyEvent + EV combination even beats the
2363	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2459	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2364	backend easily beats IO::Lambda and POE.	2460	backend easily beats IO::Lambda and POE.
2365		2461
2366	And even the 100% non-blocking version written using the high-level (and	2462	And even the 100% non-blocking version written using the high-level (and
2367	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2463	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2368	large margin, even though it does all of DNS, tcp-connect and socket I/O	2464	higher level ("unoptimised") abstractions by a large margin, even though
2369	in a non-blocking way.	2465	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2370		2466
2371	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2467	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2372	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2468	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2373	part of the IO::lambda distribution and were used without any changes.	2469	part of the IO::Lambda distribution and were used without any changes.
2374		2470
2375		2471
2376	=head1 SIGNALS	2472	=head1 SIGNALS
2377		2473
2378	AnyEvent currently installs handlers for these signals:	2474	AnyEvent currently installs handlers for these signals:
…		…
2415	unless defined $SIG{PIPE};	2511	unless defined $SIG{PIPE};
2416		2512
2417	=head1 RECOMMENDED/OPTIONAL MODULES	2513	=head1 RECOMMENDED/OPTIONAL MODULES
2418		2514
2419	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2515	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2420	it's built-in modules) are required to use it.	2516	its built-in modules) are required to use it.
2421		2517
2422	That does not mean that AnyEvent won't take advantage of some additional	2518	That does not mean that AnyEvent won't take advantage of some additional
2423	modules if they are installed.	2519	modules if they are installed.
2424		2520
2425	This section epxlains which additional modules will be used, and how they	2521	This section explains which additional modules will be used, and how they
2426	affect AnyEvent's operetion.	2522	affect AnyEvent's operation.
2427		2523
2428	=over 4	2524	=over 4
2429		2525
2430	=item L<Async::Interrupt>	2526	=item L<Async::Interrupt>
2431		2527
…		…
2436	catch the signals) with some delay (default is 10 seconds, look for	2532	catch the signals) with some delay (default is 10 seconds, look for
2437	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2533	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2438		2534
2439	If this module is available, then it will be used to implement signal	2535	If this module is available, then it will be used to implement signal
2440	catching, which means that signals will not be delayed, and the event loop	2536	catching, which means that signals will not be delayed, and the event loop
2441	will not be interrupted regularly, which is more efficient (And good for	2537	will not be interrupted regularly, which is more efficient (and good for
2442	battery life on laptops).	2538	battery life on laptops).
2443		2539
2444	This affects not just the pure-perl event loop, but also other event loops	2540	This affects not just the pure-perl event loop, but also other event loops
2445	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2541	that have no signal handling on their own (e.g. Glib, Tk, Qt).
2446		2542
…		…
2458	automatic timer adjustments even when no monotonic clock is available,	2554	automatic timer adjustments even when no monotonic clock is available,
2459	can take avdantage of advanced kernel interfaces such as C<epoll> and	2555	can take avdantage of advanced kernel interfaces such as C<epoll> and
2460	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2556	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2461	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2557	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2462		2558
		2559	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2560	then this module will do nothing for you.
		2561
2463	=item L<Guard>	2562	=item L<Guard>
2464		2563
2465	The guard module, when used, will be used to implement	2564	The guard module, when used, will be used to implement
2466	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2565	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2467	lot less memory), but otherwise doesn't affect guard operation much. It is	2566	lot less memory), but otherwise doesn't affect guard operation much. It is
2468	purely used for performance.	2567	purely used for performance.
2469		2568
2470	=item L<JSON> and L<JSON::XS>	2569	=item L<JSON> and L<JSON::XS>
2471		2570
2472	This module is required when you want to read or write JSON data via	2571	One of these modules is required when you want to read or write JSON data
2473	L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2572	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2474	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.	2573	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2475
2476	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2477	installed.
2478		2574
2479	=item L<Net::SSLeay>	2575	=item L<Net::SSLeay>
2480		2576
2481	Implementing TLS/SSL in Perl is certainly interesting, but not very	2577	Implementing TLS/SSL in Perl is certainly interesting, but not very
2482	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2578	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2483	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2579	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2484		2580
2485	=item L<Time::HiRes>	2581	=item L<Time::HiRes>
2486		2582
2487	This module is part of perl since release 5.008. It will be used when the	2583	This module is part of perl since release 5.008. It will be used when the
2488	chosen event library does not come with a timing source on it's own. The	2584	chosen event library does not come with a timing source of its own. The
2489	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2585	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
2490	try to use a monotonic clock for timing stability.	2586	try to use a monotonic clock for timing stability.
2491		2587
2492	=back	2588	=back
2493		2589
2494		2590
2495	=head1 FORK	2591	=head1 FORK
2496		2592
2497	Most event libraries are not fork-safe. The ones who are usually are	2593	Most event libraries are not fork-safe. The ones who are usually are
2498	because they rely on inefficient but fork-safe C<select> or C<poll>	2594	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2499	calls. Only L<EV> is fully fork-aware.	2595	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2596	are usually badly thought-out hacks that are incompatible with fork in
		2597	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2598	continue event-processing in both parent and child (or both, if you know
		2599	what you are doing).
		2600
		2601	This means that, in general, you cannot fork and do event processing in
		2602	the child if the event library was initialised before the fork (which
		2603	usually happens when the first AnyEvent watcher is created, or the library
		2604	is loaded).
2500		2605
2501	If you have to fork, you must either do so I<before> creating your first	2606	If you have to fork, you must either do so I<before> creating your first
2502	watcher OR you must not use AnyEvent at all in the child OR you must do	2607	watcher OR you must not use AnyEvent at all in the child OR you must do
2503	something completely out of the scope of AnyEvent.	2608	something completely out of the scope of AnyEvent.
		2609
		2610	The problem of doing event processing in the parent I<and> the child
		2611	is much more complicated: even for backends that I<are> fork-aware or
		2612	fork-safe, their behaviour is not usually what you want: fork clones all
		2613	watchers, that means all timers, I/O watchers etc. are active in both
		2614	parent and child, which is almost never what you want. USing C<exec>
		2615	to start worker children from some kind of manage rprocess is usually
		2616	preferred, because it is much easier and cleaner, at the expense of having
		2617	to have another binary.
2504		2618
2505		2619
2506	=head1 SECURITY CONSIDERATIONS	2620	=head1 SECURITY CONSIDERATIONS
2507		2621
2508	AnyEvent can be forced to load any event model via	2622	AnyEvent can be forced to load any event model via

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