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Revision 1.271 by root, Wed Aug 5 20:50:27 2009 UTC vs.
Revision 1.350 by root, Tue Aug 2 20:02:44 2011 UTC

…		…
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
12	# file descriptor readable	15	# file handle or descriptor readable
13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14		17
15	# one-shot or repeating timers	18	# one-shot or repeating timers
16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
18		21
19	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
21		24
22	# POSIX signal	25	# POSIX signal
…		…
43	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
45		48
46	=head1 SUPPORT	49	=head1 SUPPORT
47		50
		51	An FAQ document is available as L<AnyEvent::FAQ>.
		52
48	There is a mailinglist for discussing all things AnyEvent, and an IRC	53	There also is a mailinglist for discussing all things AnyEvent, and an IRC
49	channel, too.	54	channel, too.
50		55
51	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software	56	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
52	Repository>, at L<http://anyevent.schmorp.de>, for more info.	57	Repository>, at L<http://anyevent.schmorp.de>, for more info.
53		58
…		…
73	module users into the same thing by forcing them to use the same event	78	module users into the same thing by forcing them to use the same event
74	model you use.	79	model you use.
75		80
76	For modules like POE or IO::Async (which is a total misnomer as it is	81	For modules like POE or IO::Async (which is a total misnomer as it is
77	actually doing all I/O I<synchronously>...), using them in your module is	82	actually doing all I/O I<synchronously>...), using them in your module is
78	like joining a cult: After you joined, you are dependent on them and you	83	like joining a cult: After you join, you are dependent on them and you
79	cannot use anything else, as they are simply incompatible to everything	84	cannot use anything else, as they are simply incompatible to everything
80	that isn't them. What's worse, all the potential users of your	85	that isn't them. What's worse, all the potential users of your
81	module are I<also> forced to use the same event loop you use.	86	module are I<also> forced to use the same event loop you use.
82		87
83	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	88	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
84	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	89	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
85	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if	90	with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module
86	your module uses one of those, every user of your module has to use it,	91	uses one of those, every user of your module has to use it, too. But if
87	too. But if your module uses AnyEvent, it works transparently with all	92	your module uses AnyEvent, it works transparently with all event models it
88	event models it supports (including stuff like IO::Async, as long as those	93	supports (including stuff like IO::Async, as long as those use one of the
89	use one of the supported event loops. It is trivial to add new event loops	94	supported event loops. It is easy to add new event loops to AnyEvent, too,
90	to AnyEvent, too, so it is future-proof).	95	so it is future-proof).
91		96
92	In addition to being free of having to use I<the one and only true event	97	In addition to being free of having to use I<the one and only true event
93	model>, AnyEvent also is free of bloat and policy: with POE or similar	98	model>, AnyEvent also is free of bloat and policy: with POE or similar
94	modules, you get an enormous amount of code and strict rules you have to	99	modules, you get an enormous amount of code and strict rules you have to
95	follow. AnyEvent, on the other hand, is lean and up to the point, by only	100	follow. AnyEvent, on the other hand, is lean and to the point, by only
96	offering the functionality that is necessary, in as thin as a wrapper as	101	offering the functionality that is necessary, in as thin as a wrapper as
97	technically possible.	102	technically possible.
98		103
99	Of course, AnyEvent comes with a big (and fully optional!) toolbox	104	Of course, AnyEvent comes with a big (and fully optional!) toolbox
100	of useful functionality, such as an asynchronous DNS resolver, 100%	105	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
106	useful) and you want to force your users to use the one and only event	111	useful) and you want to force your users to use the one and only event
107	model, you should I<not> use this module.	112	model, you should I<not> use this module.
108		113
109	=head1 DESCRIPTION	114	=head1 DESCRIPTION
110		115
111	L<AnyEvent> provides an identical interface to multiple event loops. This	116	L<AnyEvent> provides a uniform interface to various event loops. This
112	allows module authors to utilise an event loop without forcing module	117	allows module authors to use event loop functionality without forcing
113	users to use the same event loop (as only a single event loop can coexist	118	module users to use a specific event loop implementation (since more
114	peacefully at any one time).	119	than one event loop cannot coexist peacefully).
115		120
116	The interface itself is vaguely similar, but not identical to the L<Event>	121	The interface itself is vaguely similar, but not identical to the L<Event>
117	module.	122	module.
118		123
119	During the first call of any watcher-creation method, the module tries	124	During the first call of any watcher-creation method, the module tries
120	to detect the currently loaded event loop by probing whether one of the	125	to detect the currently loaded event loop by probing whether one of the
121	following modules is already loaded: L<EV>,	126	following modules is already loaded: L<EV>, L<AnyEvent::Impl::Perl>,
122	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	127	L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one
123	L<POE>. The first one found is used. If none are found, the module tries	128	found is used. If none are detected, the module tries to load the first
124	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	129	four modules in the order given; but note that if L<EV> is not
125	adaptor should always succeed) in the order given. The first one that can	130	available, the pure-perl L<AnyEvent::Impl::Perl> should always work, so
126	be successfully loaded will be used. If, after this, still none could be	131	the other two are not normally tried.
127	found, AnyEvent will fall back to a pure-perl event loop, which is not
128	very efficient, but should work everywhere.
129		132
130	Because AnyEvent first checks for modules that are already loaded, loading	133	Because AnyEvent first checks for modules that are already loaded, loading
131	an event model explicitly before first using AnyEvent will likely make	134	an event model explicitly before first using AnyEvent will likely make
132	that model the default. For example:	135	that model the default. For example:
133		136
…		…
135	use AnyEvent;	138	use AnyEvent;
136		139
137	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
138		141
139	The I<likely> means that, if any module loads another event model and	142	The I<likely> means that, if any module loads another event model and
140	starts using it, all bets are off. Maybe you should tell their authors to	143	starts using it, all bets are off - this case should be very rare though,
141	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
142		146
143	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called
144	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	148	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
145	explicitly and enjoy the high availability of that event loop :)	149	explicitly and enjoy the high availability of that event loop :)
146		150
…		…
155	callback when the event occurs (of course, only when the event model	159	callback when the event occurs (of course, only when the event model
156	is in control).	160	is in control).
157		161
158	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
159	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<	163	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
160	callbacks must not C<die> >>. The former is good programming practise in	164	callbacks must not C<die> >>. The former is good programming practice in
161	Perl and the latter stems from the fact that exception handling differs	165	Perl and the latter stems from the fact that exception handling differs
162	widely between event loops.	166	widely between event loops.
163		167
164	To disable the watcher you have to destroy it (e.g. by setting the	168	To disable a watcher you have to destroy it (e.g. by setting the
165	variable you store it in to C<undef> or otherwise deleting all references	169	variable you store it in to C<undef> or otherwise deleting all references
166	to it).	170	to it).
167		171
168	All watchers are created by calling a method on the C<AnyEvent> class.	172	All watchers are created by calling a method on the C<AnyEvent> class.
169		173
170	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
171	example), or need to refer to their watcher object in other ways.	175	example), or need to refer to their watcher object in other ways.
172		176
173	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
174		178
175	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
176	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
177	undef $w;	181	undef $w;
178	});	182	});
…		…
210		214
211	The I/O watcher might use the underlying file descriptor or a copy of it.	215	The I/O watcher might use the underlying file descriptor or a copy of it.
212	You must not close a file handle as long as any watcher is active on the	216	You must not close a file handle as long as any watcher is active on the
213	underlying file descriptor.	217	underlying file descriptor.
214		218
215	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
216	always use non-blocking calls when reading/writing from/to your file	220	always use non-blocking calls when reading/writing from/to your file
217	handles.	221	handles.
218		222
219	Example: wait for readability of STDIN, then read a line and disable the	223	Example: wait for readability of STDIN, then read a line and disable the
220	watcher.	224	watcher.
…		…
244		248
245	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
246	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
247	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
248		252
249	The callback will normally be invoked once only. If you specify another	253	The callback will normally be invoked only once. If you specify another
250	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
251	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
252	seconds) after the first invocation. If C<interval> is specified with a	256	seconds) after the first invocation. If C<interval> is specified with a
253	false value, then it is treated as if it were missing.	257	false value, then it is treated as if it were not specified at all.
254		258
255	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
256	attempt is done to avoid timer drift in most backends, so the interval is	260	attempt is made to avoid timer drift in most backends, so the interval is
257	only approximate.	261	only approximate.
258		262
259	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
260		264
261	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
279		283
280	While most event loops expect timers to specified in a relative way, they	284	While most event loops expect timers to specified in a relative way, they
281	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
282	"jumps", for example, when ntp decides to set your clock backwards from	286	"jumps", for example, when ntp decides to set your clock backwards from
283	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to	287	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to
284	fire "after" a second might actually take six years to finally fire.	288	fire "after a second" might actually take six years to finally fire.
285		289
286	AnyEvent cannot compensate for this. The only event loop that is conscious	290	AnyEvent cannot compensate for this. The only event loop that is conscious
287	about these issues is L<EV>, which offers both relative (ev_timer, based	291	of these issues is L<EV>, which offers both relative (ev_timer, based
288	on true relative time) and absolute (ev_periodic, based on wallclock time)	292	on true relative time) and absolute (ev_periodic, based on wallclock time)
289	timers.	293	timers.
290		294
291	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
292	AnyEvent API.	296	AnyEvent API.
…		…
314	I<In almost all cases (in all cases if you don't care), this is the	318	I<In almost all cases (in all cases if you don't care), this is the
315	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
316		320
317	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
318	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
319	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
320		324
321	The rest of this section is only of relevance if you try to be very exact	325	The rest of this section is only of relevance if you try to be very exact
322	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
323		327
324	For a practical example of when these times differ, consider L<Event::Lib>	328	For a practical example of when these times differ, consider L<Event::Lib>
325	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
326		330
327	The event loop is running and has just invoked one of your callback at	331	The event loop is running and has just invoked one of your callbacks at
328	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
329	you wait a second by executing C<sleep 1> (blocking the process for a	333	you wait a second by executing C<sleep 1> (blocking the process for a
330	second) and then (at time=501) you create a relative timer that fires	334	second) and then (at time=501) you create a relative timer that fires
331	after three seconds.	335	after three seconds.
332		336
…		…
363	might affect timers and time-outs.	367	might affect timers and time-outs.
364		368
365	When this is the case, you can call this method, which will update the	369	When this is the case, you can call this method, which will update the
366	event loop's idea of "current time".	370	event loop's idea of "current time".
367		371
		372	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		373	when mod_perl executes the script, then the event loop will have the wrong
		374	idea about the "current time" (being potentially far in the past, when the
		375	script ran the last time). In that case you should arrange a call to C<<
		376	AnyEvent->now_update >> each time the web server process wakes up again
		377	(e.g. at the start of your script, or in a handler).
		378
368	Note that updating the time I<might> cause some events to be handled.	379	Note that updating the time I<might> cause some events to be handled.
369		380
370	=back	381	=back
371		382
372	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
…		…
396		407
397	Example: exit on SIGINT	408	Example: exit on SIGINT
398		409
399	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
400		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling) or
		421	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		422	latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
401	=head3 Signal Races, Delays and Workarounds	429	=head3 Signal Races, Delays and Workarounds
402		430
403	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching	431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
404	callbacks to signals in a generic way, which is a pity, as you cannot	432	callbacks to signals in a generic way, which is a pity, as you cannot
405	do race-free signal handling in perl, requiring C libraries for	433	do race-free signal handling in perl, requiring C libraries for
406	this. AnyEvent will try to do it's best, which means in some cases,	434	this. AnyEvent will try to do its best, which means in some cases,
407	signals will be delayed. The maximum time a signal might be delayed is	435	signals will be delayed. The maximum time a signal might be delayed is
408	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This	436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
409	variable can be changed only before the first signal watcher is created,	437	variable can be changed only before the first signal watcher is created,
410	and should be left alone otherwise. This variable determines how often	438	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	439	AnyEvent polls for signals (in case a wake-up was missed). Higher values
…		…
413	saving.	441	saving.
414		442
415	All these problems can be avoided by installing the optional	443	All these problems can be avoided by installing the optional
416	L<Async::Interrupt> module, which works with most event loops. It will not	444	L<Async::Interrupt> module, which works with most event loops. It will not
417	work with inherently broken event loops such as L<Event> or L<Event::Lib>	445	work with inherently broken event loops such as L<Event> or L<Event::Lib>
418	(and not with L<POE> currently, as POE does it's own workaround with	446	(and not with L<POE> currently, as POE does its own workaround with
419	one-second latency). For those, you just have to suffer the delays.	447	one-second latency). For those, you just have to suffer the delays.
420		448
421	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
422		450
423	$w = AnyEvent->child (pid => <process id>, cb => <callback>);	451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
424		452
425	You can also watch on a child process exit and catch its exit status.	453	You can also watch for a child process exit and catch its exit status.
426		454
427	The child process is specified by the C<pid> argument (one some backends,	455	The child process is specified by the C<pid> argument (on some backends,
428	using C<0> watches for any child process exit, on others this will	456	using C<0> watches for any child process exit, on others this will
429	croak). The watcher will be triggered only when the child process has	457	croak). The watcher will be triggered only when the child process has
430	finished and an exit status is available, not on any trace events	458	finished and an exit status is available, not on any trace events
431	(stopped/continued).	459	(stopped/continued).
432		460
…		…
479		507
480	=head2 IDLE WATCHERS	508	=head2 IDLE WATCHERS
481		509
482	$w = AnyEvent->idle (cb => <callback>);	510	$w = AnyEvent->idle (cb => <callback>);
483		511
484	Sometimes there is a need to do something, but it is not so important	512	This will repeatedly invoke the callback after the process becomes idle,
485	to do it instantly, but only when there is nothing better to do. This	513	until either the watcher is destroyed or new events have been detected.
486	"nothing better to do" is usually defined to be "no other events need
487	attention by the event loop".
488		514
489	Idle watchers ideally get invoked when the event loop has nothing	515	Idle watchers are useful when there is a need to do something, but it
490	better to do, just before it would block the process to wait for new	516	is not so important (or wise) to do it instantly. The callback will be
491	events. Instead of blocking, the idle watcher is invoked.	517	invoked only when there is "nothing better to do", which is usually
		518	defined as "all outstanding events have been handled and no new events
		519	have been detected". That means that idle watchers ideally get invoked
		520	when the event loop has just polled for new events but none have been
		521	detected. Instead of blocking to wait for more events, the idle watchers
		522	will be invoked.
492		523
493	Most event loops unfortunately do not really support idle watchers (only	524	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	525	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
495	will simply call the callback "from time to time".	526	will simply call the callback "from time to time".
496		527
497	Example: read lines from STDIN, but only process them when the	528	Example: read lines from STDIN, but only process them when the
498	program is otherwise idle:	529	program is otherwise idle:
…		…
526	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
527		558
528	AnyEvent is slightly different: it expects somebody else to run the event	559	AnyEvent is slightly different: it expects somebody else to run the event
529	loop and will only block when necessary (usually when told by the user).	560	loop and will only block when necessary (usually when told by the user).
530		561
531	The instrument to do that is called a "condition variable", so called	562	The tool to do that is called a "condition variable", so called because
532	because they represent a condition that must become true.	563	they represent a condition that must become true.
533		564
534	Now is probably a good time to look at the examples further below.	565	Now is probably a good time to look at the examples further below.
535		566
536	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
537	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
…		…
542	After creation, the condition variable is "false" until it becomes "true"	573	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	574	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<<	575	were a callback, read about the caveats in the description for the C<<
545	->send >> method).	576	->send >> method).
546		577
547	Condition variables are similar to callbacks, except that you can	578	Since condition variables are the most complex part of the AnyEvent API, here are
548	optionally wait for them. They can also be called merge points - points	579	some different mental models of what they are - pick the ones you can connect to:
549	in time where multiple outstanding events have been processed. And yet	580
550	another way to call them is transactions - each condition variable can be	581	=over 4
551	used to represent a transaction, which finishes at some point and delivers	582
552	a result. And yet some people know them as "futures" - a promise to	583	=item * Condition variables are like callbacks - you can call them (and pass them instead
553	compute/deliver something that you can wait for.	584	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		585
		586	=item * Condition variables are signals - one side can emit or send them,
		587	the other side can wait for them, or install a handler that is called when
		588	the signal fires.
		589
		590	=item * Condition variables are like "Merge Points" - points in your program
		591	where you merge multiple independent results/control flows into one.
		592
		593	=item * Condition variables represent a transaction - functions that start
		594	some kind of transaction can return them, leaving the caller the choice
		595	between waiting in a blocking fashion, or setting a callback.
		596
		597	=item * Condition variables represent future values, or promises to deliver
		598	some result, long before the result is available.
		599
		600	=back
554		601
555	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
556	for example, if you write a module that does asynchronous http requests,	603	for example, if you write a module that does asynchronous http requests,
557	then a condition variable would be the ideal candidate to signal the	604	then a condition variable would be the ideal candidate to signal the
558	availability of results. The user can either act when the callback is	605	availability of results. The user can either act when the callback is
…		…
571		618
572	Condition variables are represented by hash refs in perl, and the keys	619	Condition variables are represented by hash refs in perl, and the keys
573	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing	620	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
574	easy (it is often useful to build your own transaction class on top of	621	easy (it is often useful to build your own transaction class on top of
575	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call	622	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
576	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
577		624
578	There are two "sides" to a condition variable - the "producer side" which	625	There are two "sides" to a condition variable - the "producer side" which
579	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
580	for the send to occur.	627	for the send to occur.
581		628
582	Example: wait for a timer.	629	Example: wait for a timer.
583		630
584	# wait till the result is ready	631	# condition: "wait till the timer is fired"
585	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
586		633
587	# do something such as adding a timer	634	# create the timer - we could wait for, say
588	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
589	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
590	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
591	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
592	after => 1,	639	after => 1,
593	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
594	);	641	);
595		642
596	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
597	# calls -<send	644	# calls ->send
598	$result_ready->recv;	645	$timer_fired->recv;
599		646
600	Example: wait for a timer, but take advantage of the fact that condition	647	Example: wait for a timer, but take advantage of the fact that condition
601	variables are also callable directly.	648	variables are also callable directly.
602		649
603	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
…		…
646	they were a code reference). Calling them directly is the same as calling	693	they were a code reference). Calling them directly is the same as calling
647	C<send>.	694	C<send>.
648		695
649	=item $cv->croak ($error)	696	=item $cv->croak ($error)
650		697
651	Similar to send, but causes all call's to C<< ->recv >> to invoke	698	Similar to send, but causes all calls to C<< ->recv >> to invoke
652	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
653		700
654	This can be used to signal any errors to the condition variable	701	This can be used to signal any errors to the condition variable
655	user/consumer. Doing it this way instead of calling C<croak> directly	702	user/consumer. Doing it this way instead of calling C<croak> directly
656	delays the error detetcion, but has the overwhelmign advantage that it	703	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	704	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	705	deep in some event callback with no connection to the actual code causing
659	the problem.	706	the problem.
660		707
661	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
662		709
663	=item $cv->end	710	=item $cv->end
…		…
666	one. For example, a function that pings many hosts in parallel might want	713	one. For example, a function that pings many hosts in parallel might want
667	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
668		715
669	Every call to C<< ->begin >> will increment a counter, and every call to	716	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	717	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	718	>>, 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	719	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.	720	>>, but that is not required. If no group callback was set, C<send> will
		721	be called without any arguments.
674		722
675	You can think of C<< $cv->send >> giving you an OR condition (one call	723	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	724	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).	725	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
678		726
…		…
700	one call to C<begin>, so the condvar waits for all calls to C<end> before	748	one call to C<begin>, so the condvar waits for all calls to C<end> before
701	sending.	749	sending.
702		750
703	The ping example mentioned above is slightly more complicated, as the	751	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	752	there are results to be passwd back, and the number of tasks that are
705	begung can potentially be zero:	753	begun can potentially be zero:
706		754
707	my $cv = AnyEvent->condvar;	755	my $cv = AnyEvent->condvar;
708		756
709	my %result;	757	my %result;
710	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
711		759
712	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
713	$cv->begin;	761	$cv->begin;
714	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
715	$result{$host} = ...;	763	$result{$host} = ...;
…		…
731	to be called once the counter reaches C<0>, and second, it ensures that	779	to be called once the counter reaches C<0>, and second, it ensures that
732	C<send> is called even when C<no> hosts are being pinged (the loop	780	C<send> is called even when C<no> hosts are being pinged (the loop
733	doesn't execute once).	781	doesn't execute once).
734		782
735	This is the general pattern when you "fan out" into multiple (but	783	This is the general pattern when you "fan out" into multiple (but
736	potentially none) subrequests: use an outer C<begin>/C<end> pair to set	784	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
737	the callback and ensure C<end> is called at least once, and then, for each	785	the callback and ensure C<end> is called at least once, and then, for each
738	subrequest you start, call C<begin> and for each subrequest you finish,	786	subrequest you start, call C<begin> and for each subrequest you finish,
739	call C<end>.	787	call C<end>.
740		788
741	=back	789	=back
…		…
748	=over 4	796	=over 4
749		797
750	=item $cv->recv	798	=item $cv->recv
751		799
752	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
753	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
754	normally.	802	normally.
755		803
756	You can only wait once on a condition - additional calls are valid but	804	You can only wait once on a condition - additional calls are valid but
757	will return immediately.	805	will return immediately.
758		806
…		…
775	caller decide whether the call will block or not (for example, by coupling	823	caller decide whether the call will block or not (for example, by coupling
776	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
777	callbacks so the caller knows that getting the result will not block,	825	callbacks so the caller knows that getting the result will not block,
778	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
779		827
780	You can ensure that C<< -recv >> never blocks by setting a callback and	828	You can ensure that C<< ->recv >> never blocks by setting a callback and
781	only calling C<< ->recv >> from within that callback (or at a later	829	only calling C<< ->recv >> from within that callback (or at a later
782	time). This will work even when the event loop does not support blocking	830	time). This will work even when the event loop does not support blocking
783	waits otherwise.	831	waits otherwise.
784		832
785	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
790	=item $cb = $cv->cb ($cb->($cv))	838	=item $cb = $cv->cb ($cb->($cv))
791		839
792	This is a mutator function that returns the callback set and optionally	840	This is a mutator function that returns the callback set and optionally
793	replaces it before doing so.	841	replaces it before doing so.
794		842
795	The callback will be called when the condition becomes (or already was)	843	The callback will be called when the condition becomes "true", i.e. when
796	"true", i.e. when C<send> or C<croak> are called (or were called), with	844	C<send> or C<croak> are called, with the only argument being the
797	the only argument being the condition variable itself. Calling C<recv>	845	condition variable itself. If the condition is already true, the
		846	callback is called immediately when it is set. Calling C<recv> inside
798	inside the callback or at any later time is guaranteed not to block.	847	the callback or at any later time is guaranteed not to block.
799		848
800	=back	849	=back
801		850
802	=head1 SUPPORTED EVENT LOOPS/BACKENDS	851	=head1 SUPPORTED EVENT LOOPS/BACKENDS
803		852
…		…
806	=over 4	855	=over 4
807		856
808	=item Backends that are autoprobed when no other event loop can be found.	857	=item Backends that are autoprobed when no other event loop can be found.
809		858
810	EV is the preferred backend when no other event loop seems to be in	859	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	860	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	861	pure-perl implementation, which is available everywhere as it comes with
813	available everywhere as it comes with AnyEvent itself.	862	AnyEvent itself.
814		863
815	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	864	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.	865	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
818		866
819	=item Backends that are transparently being picked up when they are used.	867	=item Backends that are transparently being picked up when they are used.
820		868
821	These will be used when they are currently loaded when the first watcher	869	These will be used if they are already loaded when the first watcher
822	is created, in which case it is assumed that the application is using	870	is created, in which case it is assumed that the application is using
823	them. This means that AnyEvent will automatically pick the right backend	871	them. This means that AnyEvent will automatically pick the right backend
824	when the main program loads an event module before anything starts to	872	when the main program loads an event module before anything starts to
825	create watchers. Nothing special needs to be done by the main program.	873	create watchers. Nothing special needs to be done by the main program.
826		874
		875	AnyEvent::Impl::Event based on Event, very stable, few glitches.
827	AnyEvent::Impl::Glib based on Glib, slow but very stable.	876	AnyEvent::Impl::Glib based on Glib, slow but very stable.
828	AnyEvent::Impl::Tk based on Tk, very broken.	877	AnyEvent::Impl::Tk based on Tk, very broken.
829	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	878	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
830	AnyEvent::Impl::POE based on POE, very slow, some limitations.	879	AnyEvent::Impl::POE based on POE, very slow, some limitations.
831	AnyEvent::Impl::Irssi used when running within irssi.	880	AnyEvent::Impl::Irssi used when running within irssi.
		881	AnyEvent::Impl::IOAsync based on IO::Async.
		882	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
		883	AnyEvent::Impl::FLTK based on FLTK.
832		884
833	=item Backends with special needs.	885	=item Backends with special needs.
834		886
835	Qt requires the Qt::Application to be instantiated first, but will	887	Qt requires the Qt::Application to be instantiated first, but will
836	otherwise be picked up automatically. As long as the main program	888	otherwise be picked up automatically. As long as the main program
837	instantiates the application before any AnyEvent watchers are created,	889	instantiates the application before any AnyEvent watchers are created,
838	everything should just work.	890	everything should just work.
839		891
840	AnyEvent::Impl::Qt based on Qt.	892	AnyEvent::Impl::Qt based on Qt.
841		893
842	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
844	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
846	L<AnyEvent::Impl::Async> for the gory details.
847
848	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
849
850	=item Event loops that are indirectly supported via other backends.	894	=item Event loops that are indirectly supported via other backends.
851		895
852	Some event loops can be supported via other modules:	896	Some event loops can be supported via other modules:
853		897
854	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.	898	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
…		…
879	Contains C<undef> until the first watcher is being created, before the	923	Contains C<undef> until the first watcher is being created, before the
880	backend has been autodetected.	924	backend has been autodetected.
881		925
882	Afterwards it contains the event model that is being used, which is the	926	Afterwards it contains the event model that is being used, which is the
883	name of the Perl class implementing the model. This class is usually one	927	name of the Perl class implementing the model. This class is usually one
884	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the	928	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
885	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it	929	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
886	will be C<urxvt::anyevent>).	930	will be C<urxvt::anyevent>).
887		931
888	=item AnyEvent::detect	932	=item AnyEvent::detect
889		933
890	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	934	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
891	if necessary. You should only call this function right before you would	935	if necessary. You should only call this function right before you would
892	have created an AnyEvent watcher anyway, that is, as late as possible at	936	have created an AnyEvent watcher anyway, that is, as late as possible at
893	runtime, and not e.g. while initialising of your module.	937	runtime, and not e.g. during initialisation of your module.
894		938
895	If you need to do some initialisation before AnyEvent watchers are	939	If you need to do some initialisation before AnyEvent watchers are
896	created, use C<post_detect>.	940	created, use C<post_detect>.
897		941
898	=item $guard = AnyEvent::post_detect { BLOCK }	942	=item $guard = AnyEvent::post_detect { BLOCK }
899		943
900	Arranges for the code block to be executed as soon as the event model is	944	Arranges for the code block to be executed as soon as the event model is
901	autodetected (or immediately if this has already happened).	945	autodetected (or immediately if that has already happened).
902		946
903	The block will be executed I<after> the actual backend has been detected	947	The block will be executed I<after> the actual backend has been detected
904	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	948	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
905	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	949	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
906	other initialisations - see the sources of L<AnyEvent::Strict> or	950	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
915	that automatically removes the callback again when it is destroyed (or	959	that automatically removes the callback again when it is destroyed (or
916	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for	960	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
917	a case where this is useful.	961	a case where this is useful.
918		962
919	Example: Create a watcher for the IO::AIO module and store it in	963	Example: Create a watcher for the IO::AIO module and store it in
920	C<$WATCHER>. Only do so after the event loop is initialised, though.	964	C<$WATCHER>, but do so only do so after the event loop is initialised.
921		965
922	our WATCHER;	966	our WATCHER;
923		967
924	my $guard = AnyEvent::post_detect {	968	my $guard = AnyEvent::post_detect {
925	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);	969	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
…		…
933	$WATCHER ||= $guard;	977	$WATCHER ||= $guard;
934		978
935	=item @AnyEvent::post_detect	979	=item @AnyEvent::post_detect
936		980
937	If there are any code references in this array (you can C<push> to it	981	If there are any code references in this array (you can C<push> to it
938	before or after loading AnyEvent), then they will called directly after	982	before or after loading AnyEvent), then they will be called directly
939	the event loop has been chosen.	983	after the event loop has been chosen.
940		984
941	You should check C<$AnyEvent::MODEL> before adding to this array, though:	985	You should check C<$AnyEvent::MODEL> before adding to this array, though:
942	if it is defined then the event loop has already been detected, and the	986	if it is defined then the event loop has already been detected, and the
943	array will be ignored.	987	array will be ignored.
944		988
945	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	989	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
946	it,as it takes care of these details.	990	it, as it takes care of these details.
947		991
948	This variable is mainly useful for modules that can do something useful	992	This variable is mainly useful for modules that can do something useful
949	when AnyEvent is used and thus want to know when it is initialised, but do	993	when AnyEvent is used and thus want to know when it is initialised, but do
950	not need to even load it by default. This array provides the means to hook	994	not need to even load it by default. This array provides the means to hook
951	into AnyEvent passively, without loading it.	995	into AnyEvent passively, without loading it.
952		996
		997	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		998	together, you could put this into Coro (this is the actual code used by
		999	Coro to accomplish this):
		1000
		1001	if (defined $AnyEvent::MODEL) {
		1002	# AnyEvent already initialised, so load Coro::AnyEvent
		1003	require Coro::AnyEvent;
		1004	} else {
		1005	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1006	# as soon as it is
		1007	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1008	}
		1009
953	=back	1010	=back
954		1011
955	=head1 WHAT TO DO IN A MODULE	1012	=head1 WHAT TO DO IN A MODULE
956		1013
957	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1014	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	1024	because it will stall the whole program, and the whole point of using
968	events is to stay interactive.	1025	events is to stay interactive.
969		1026
970	It is fine, however, to call C<< ->recv >> when the user of your module	1027	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	1028	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 >>	1029	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).	1030	freely, as the user of your module knows what she is doing. Always).
974		1031
975	=head1 WHAT TO DO IN THE MAIN PROGRAM	1032	=head1 WHAT TO DO IN THE MAIN PROGRAM
976		1033
977	There will always be a single main program - the only place that should	1034	There will always be a single main program - the only place that should
978	dictate which event model to use.	1035	dictate which event model to use.
979		1036
980	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1037	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	1038	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.	1039	uses AnyEvent, but does not care which event loop is used, all it needs
		1040	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1041	available loop implementation.
983		1042
984	If the main program relies on a specific event model - for example, in	1043	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	1044	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	1045	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	1046	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	1047	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	1048	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.	1049	might choose the wrong one unless you load the correct one yourself.
991		1050
992	You can chose to use a pure-perl implementation by loading the	1051	You can chose to use a pure-perl implementation by loading the
993	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1052	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
994	everywhere, but letting AnyEvent chose the model is generally better.	1053	everywhere, but letting AnyEvent chose the model is generally better.
995		1054
…		…
1013	=head1 OTHER MODULES	1072	=head1 OTHER MODULES
1014		1073
1015	The following is a non-exhaustive list of additional modules that use	1074	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	1075	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	1076	modules and other event loops in the same program. Some of the modules
1018	come with AnyEvent, most are available via CPAN.	1077	come as part of AnyEvent, the others are available via CPAN.
1019		1078
1020	=over 4	1079	=over 4
1021		1080
1022	=item L<AnyEvent::Util>	1081	=item L<AnyEvent::Util>
1023		1082
1024	Contains various utility functions that replace often-used but blocking	1083	Contains various utility functions that replace often-used blocking
1025	functions such as C<inet_aton> by event-/callback-based versions.	1084	functions such as C<inet_aton> with event/callback-based versions.
1026		1085
1027	=item L<AnyEvent::Socket>	1086	=item L<AnyEvent::Socket>
1028		1087
1029	Provides various utility functions for (internet protocol) sockets,	1088	Provides various utility functions for (internet protocol) sockets,
1030	addresses and name resolution. Also functions to create non-blocking tcp	1089	addresses and name resolution. Also functions to create non-blocking tcp
…		…
1032		1091
1033	=item L<AnyEvent::Handle>	1092	=item L<AnyEvent::Handle>
1034		1093
1035	Provide read and write buffers, manages watchers for reads and writes,	1094	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	1095	supports raw and formatted I/O, I/O queued and fully transparent and
1037	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1096	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1038		1097
1039	=item L<AnyEvent::DNS>	1098	=item L<AnyEvent::DNS>
1040		1099
1041	Provides rich asynchronous DNS resolver capabilities.	1100	Provides rich asynchronous DNS resolver capabilities.
1042		1101
		1102	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1103
		1104	Implement event-based interfaces to the protocols of the same name (for
		1105	the curious, IGS is the International Go Server and FCP is the Freenet
		1106	Client Protocol).
		1107
		1108	=item L<AnyEvent::Handle::UDP>
		1109
		1110	Here be danger!
		1111
		1112	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1113	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1114	its use of a stream-based API with a protocol that isn't streamable, that
		1115	the only way to improve it is to delete it.
		1116
		1117	It features data corruption (but typically only under load) and general
		1118	confusion. On top, the author is not only clueless about UDP but also
		1119	fact-resistant - some gems of his understanding: "connect doesn't work
		1120	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1121	packets", "I don't need to implement proper error checking as UDP doesn't
		1122	support error checking" and so on - he doesn't even understand what's
		1123	wrong with his module when it is explained to him.
		1124
1043	=item L<AnyEvent::HTTP>	1125	=item L<AnyEvent::DBI>
1044		1126
1045	A simple-to-use HTTP library that is capable of making a lot of concurrent	1127	Executes L<DBI> requests asynchronously in a proxy process for you,
1046	HTTP requests.	1128	notifying you in an event-based way when the operation is finished.
		1129
		1130	=item L<AnyEvent::AIO>
		1131
		1132	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1133	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1134	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1135	file I/O, and much more.
1047		1136
1048	=item L<AnyEvent::HTTPD>	1137	=item L<AnyEvent::HTTPD>
1049		1138
1050	Provides a simple web application server framework.	1139	A simple embedded webserver.
1051		1140
1052	=item L<AnyEvent::FastPing>	1141	=item L<AnyEvent::FastPing>
1053		1142
1054	The fastest ping in the west.	1143	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		1144
1098	=item L<Coro>	1145	=item L<Coro>
1099		1146
1100	Has special support for AnyEvent via L<Coro::AnyEvent>.	1147	Has special support for AnyEvent via L<Coro::AnyEvent>.
1101		1148
…		…
1105		1152
1106	package AnyEvent;	1153	package AnyEvent;
1107		1154
1108	# basically a tuned-down version of common::sense	1155	# basically a tuned-down version of common::sense
1109	sub common_sense {	1156	sub common_sense {
1110	# no warnings	1157	# from common:.sense 3.4
1111	${^WARNING_BITS} ^= ${^WARNING_BITS};	1158	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1112	# use strict vars subs	1159	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1113	$^H |= 0x00000600;	1160	$^H |= 0x00000600;
1114	}	1161	}
1115		1162
1116	BEGIN { AnyEvent::common_sense }	1163	BEGIN { AnyEvent::common_sense }
1117		1164
1118	use Carp ();	1165	use Carp ();
1119		1166
1120	our $VERSION = 4.901;	1167	our $VERSION = '5.34';
1121	our $MODEL;	1168	our $MODEL;
1122		1169
1123	our $AUTOLOAD;	1170	our $AUTOLOAD;
1124	our @ISA;	1171	our @ISA;
1125		1172
1126	our @REGISTRY;	1173	our @REGISTRY;
1127		1174
1128	our $WIN32;
1129
1130	our $VERBOSE;	1175	our $VERBOSE;
1131		1176
1132	BEGIN {	1177	BEGIN {
1133	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1178	require "AnyEvent/constants.pl";
		1179
1134	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1180	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1135		1181
1136	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1182	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1137	if ${^TAINT};	1183	if ${^TAINT};
1138		1184
1139	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1185	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
…		…
1151	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1197	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1152	}	1198	}
1153		1199
1154	my @models = (	1200	my @models = (
1155	[EV:: => AnyEvent::Impl::EV:: , 1],	1201	[EV:: => AnyEvent::Impl::EV:: , 1],
1156	[Event:: => AnyEvent::Impl::Event::, 1],
1157	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],	1202	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1158	# everything below here will not (normally) be autoprobed	1203	# everything below here will not (normally) be autoprobed
1159	# as the pureperl backend should work everywhere	1204	# as the pureperl backend should work everywhere
1160	# and is usually faster	1205	# and is usually faster
		1206	[Event:: => AnyEvent::Impl::Event::, 1],
1161	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers	1207	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1162	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1208	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1163	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package	1209	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1164	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1210	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1165	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1211	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1166	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1212	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1167	[Wx:: => AnyEvent::Impl::POE::],	1213	[Wx:: => AnyEvent::Impl::POE::],
1168	[Prima:: => AnyEvent::Impl::POE::],	1214	[Prima:: => AnyEvent::Impl::POE::],
1169	# IO::Async is just too broken - we would need workarounds for its
1170	# byzantine signal and broken child handling, among others.
1171	# IO::Async is rather hard to detect, as it doesn't have any
1172	# obvious default class.
1173	# [0, IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1174	# [0, IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program	1215	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::],
1175	# [0, IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program	1216	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
		1217	[FLTK:: => AnyEvent::Impl::FLTK::],
1176	);	1218	);
1177		1219
1178	our %method = map +($_ => 1),	1220	our %method = map +($_ => 1),
1179	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1221	qw(io timer time now now_update signal child idle condvar DESTROY);
1180		1222
1181	our @post_detect;	1223	our @post_detect;
1182		1224
1183	sub post_detect(&) {	1225	sub post_detect(&) {
1184	my ($cb) = @_;	1226	my ($cb) = @_;
1185		1227
1186	if ($MODEL) {
1187	$cb->();
1188
1189	undef
1190	} else {
1191	push @post_detect, $cb;	1228	push @post_detect, $cb;
1192		1229
1193	defined wantarray	1230	defined wantarray
1194	? bless \$cb, "AnyEvent::Util::postdetect"	1231	? bless \$cb, "AnyEvent::Util::postdetect"
1195	: ()	1232	: ()
1196	}
1197	}	1233	}
1198		1234
1199	sub AnyEvent::Util::postdetect::DESTROY {	1235	sub AnyEvent::Util::postdetect::DESTROY {
1200	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1236	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1201	}	1237	}
1202		1238
1203	sub detect() {	1239	sub detect() {
		1240	# free some memory
		1241	*detect = sub () { $MODEL };
		1242
		1243	local $!; # for good measure
		1244	local $SIG{__DIE__};
		1245
		1246	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1247	my $model = "AnyEvent::Impl::$1";
		1248	if (eval "require $model") {
		1249	$MODEL = $model;
		1250	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1251	} else {
		1252	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1253	}
		1254	}
		1255
		1256	# check for already loaded models
1204	unless ($MODEL) {	1257	unless ($MODEL) {
1205	local $SIG{__DIE__};	1258	for (@REGISTRY, @models) {
1206		1259	my ($package, $model) = @$_;
1207	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1260	if (${"$package\::VERSION"} > 0) {
1208	my $model = "AnyEvent::Impl::$1";
1209	if (eval "require $model") {	1261	if (eval "require $model") {
1210	$MODEL = $model;	1262	$MODEL = $model;
1211	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1263	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1212	} else {	1264	last;
1213	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1265	}
1214	}	1266	}
1215	}	1267	}
1216		1268
1217	# check for already loaded models
1218	unless ($MODEL) {	1269	unless ($MODEL) {
		1270	# try to autoload a model
1219	for (@REGISTRY, @models) {	1271	for (@REGISTRY, @models) {
1220	my ($package, $model) = @$_;	1272	my ($package, $model, $autoload) = @$_;
		1273	if (
		1274	$autoload
		1275	and eval "require $package"
1221	if (${"$package\::VERSION"} > 0) {	1276	and ${"$package\::VERSION"} > 0
1222	if (eval "require $model") {	1277	and eval "require $model"
		1278	) {
1223	$MODEL = $model;	1279	$MODEL = $model;
1224	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;	1280	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1225	last;	1281	last;
1226	}
1227	}	1282	}
1228	}	1283	}
1229		1284
1230	unless ($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	1285	$MODEL
1247	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1286	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?\n";
1248	}
1249	}	1287	}
1250
1251	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1252
1253	unshift @ISA, $MODEL;
1254
1255	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1256
1257	(shift @post_detect)->() while @post_detect;
1258	}	1288	}
		1289
		1290	@models = (); # free probe data
		1291
		1292	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1293	unshift @ISA, $MODEL;
		1294
		1295	# now nuke some methods that are overridden by the backend.
		1296	# SUPER is not allowed.
		1297	for (qw(time signal child idle)) {
		1298	undef &{"AnyEvent::Base::$_"}
		1299	if defined &{"$MODEL\::$_"};
		1300	}
		1301
		1302	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1303	eval { require AnyEvent::Strict };
		1304	warn "AnyEvent: cannot load AnyEvent::Strict: $@"
		1305	if $@ && $VERBOSE;
		1306	}
		1307
		1308	(shift @post_detect)->() while @post_detect;
		1309
		1310	*post_detect = sub(&) {
		1311	shift->();
		1312
		1313	undef
		1314	};
1259		1315
1260	$MODEL	1316	$MODEL
1261	}	1317	}
1262		1318
1263	sub AUTOLOAD {	1319	sub AUTOLOAD {
1264	(my $func = $AUTOLOAD) =~ s/.*://;	1320	(my $func = $AUTOLOAD) =~ s/.*://;
1265		1321
1266	$method{$func}	1322	$method{$func}
1267	or Carp::croak "$func: not a valid method for AnyEvent objects";	1323	or Carp::croak "$func: not a valid AnyEvent class method";
1268		1324
1269	detect unless $MODEL;	1325	detect;
1270		1326
1271	my $class = shift;	1327	my $class = shift;
1272	$class->$func (@_);	1328	$class->$func (@_);
1273	}	1329	}
1274		1330
…		…
1287	# we assume CLOEXEC is already set by perl in all important cases	1343	# we assume CLOEXEC is already set by perl in all important cases
1288		1344
1289	($fh2, $rw)	1345	($fh2, $rw)
1290	}	1346	}
1291		1347
		1348	=head1 SIMPLIFIED AE API
		1349
		1350	Starting with version 5.0, AnyEvent officially supports a second, much
		1351	simpler, API that is designed to reduce the calling, typing and memory
		1352	overhead by using function call syntax and a fixed number of parameters.
		1353
		1354	See the L<AE> manpage for details.
		1355
		1356	=cut
		1357
		1358	package AE;
		1359
		1360	our $VERSION = $AnyEvent::VERSION;
		1361
		1362	# fall back to the main API by default - backends and AnyEvent::Base
		1363	# implementations can overwrite these.
		1364
		1365	sub io($$$) {
		1366	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1367	}
		1368
		1369	sub timer($$$) {
		1370	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1371	}
		1372
		1373	sub signal($$) {
		1374	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1375	}
		1376
		1377	sub child($$) {
		1378	AnyEvent->child (pid => $_[0], cb => $_[1])
		1379	}
		1380
		1381	sub idle($) {
		1382	AnyEvent->idle (cb => $_[0])
		1383	}
		1384
		1385	sub cv(;&) {
		1386	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1387	}
		1388
		1389	sub now() {
		1390	AnyEvent->now
		1391	}
		1392
		1393	sub now_update() {
		1394	AnyEvent->now_update
		1395	}
		1396
		1397	sub time() {
		1398	AnyEvent->time
		1399	}
		1400
1292	package AnyEvent::Base;	1401	package AnyEvent::Base;
1293		1402
1294	# default implementations for many methods	1403	# default implementations for many methods
1295		1404
1296	sub _time {	1405	sub time {
		1406	eval q{ # poor man's autoloading {}
1297	# probe for availability of Time::HiRes	1407	# probe for availability of Time::HiRes
1298	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1408	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1299	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1409	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1300	*_time = \&Time::HiRes::time;	1410	*AE::time = \&Time::HiRes::time;
1301	# if (eval "use POSIX (); (POSIX::times())...	1411	# if (eval "use POSIX (); (POSIX::times())...
1302	} else {	1412	} else {
1303	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1413	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1304	*_time = sub { time }; # epic fail	1414	*AE::time = sub (){ time }; # epic fail
		1415	}
		1416
		1417	*time = sub { AE::time }; # different prototypes
1305	}	1418	};
		1419	die if $@;
1306		1420
1307	&_time	1421	&time
1308	}	1422	}
1309		1423
1310	sub time { _time }	1424	*now = \&time;
1311	sub now { _time }	1425
1312	sub now_update { }	1426	sub now_update { }
1313		1427
1314	# default implementation for ->condvar	1428	# default implementation for ->condvar
1315		1429
1316	sub condvar {	1430	sub condvar {
		1431	eval q{ # poor man's autoloading {}
		1432	*condvar = sub {
1317	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1433	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1434	};
		1435
		1436	*AE::cv = sub (;&) {
		1437	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1438	};
		1439	};
		1440	die if $@;
		1441
		1442	&condvar
1318	}	1443	}
1319		1444
1320	# default implementation for ->signal	1445	# default implementation for ->signal
1321		1446
1322	our $HAVE_ASYNC_INTERRUPT;	1447	our $HAVE_ASYNC_INTERRUPT;
1323		1448
1324	sub _have_async_interrupt() {	1449	sub _have_async_interrupt() {
1325	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}	1450	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
1326	&& eval "use Async::Interrupt 1.0 (); 1")	1451	&& eval "use Async::Interrupt 1.02 (); 1")
1327	unless defined $HAVE_ASYNC_INTERRUPT;	1452	unless defined $HAVE_ASYNC_INTERRUPT;
1328		1453
1329	$HAVE_ASYNC_INTERRUPT	1454	$HAVE_ASYNC_INTERRUPT
1330	}	1455	}
1331		1456
1332	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1457	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1333	our (%SIG_ASY, %SIG_ASY_W);	1458	our (%SIG_ASY, %SIG_ASY_W);
1334	our ($SIG_COUNT, $SIG_TW);	1459	our ($SIG_COUNT, $SIG_TW);
1335		1460
1336	sub _signal_exec {
1337	$HAVE_ASYNC_INTERRUPT
1338	? $SIGPIPE_R->drain
1339	: sysread $SIGPIPE_R, my $dummy, 9;
1340
1341	while (%SIG_EV) {
1342	for (keys %SIG_EV) {
1343	delete $SIG_EV{$_};
1344	$_->() for values %{ $SIG_CB{$_} || {} };
1345	}
1346	}
1347	}
1348
1349	# install a dummy wakeup watcher to reduce signal catching latency	1461	# install a dummy wakeup watcher to reduce signal catching latency
		1462	# used by Impls
1350	sub _sig_add() {	1463	sub _sig_add() {
1351	unless ($SIG_COUNT++) {	1464	unless ($SIG_COUNT++) {
1352	# try to align timer on a full-second boundary, if possible	1465	# try to align timer on a full-second boundary, if possible
1353	my $NOW = AnyEvent->now;	1466	my $NOW = AE::now;
1354		1467
1355	$SIG_TW = AnyEvent->timer (	1468	$SIG_TW = AE::timer
1356	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),	1469	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1357	interval => $MAX_SIGNAL_LATENCY,	1470	$MAX_SIGNAL_LATENCY,
1358	cb => sub { }, # just for the PERL_ASYNC_CHECK	1471	sub { } # just for the PERL_ASYNC_CHECK
1359	);	1472	;
1360	}	1473	}
1361	}	1474	}
1362		1475
1363	sub _sig_del {	1476	sub _sig_del {
1364	undef $SIG_TW	1477	undef $SIG_TW
1365	unless --$SIG_COUNT;	1478	unless --$SIG_COUNT;
1366	}	1479	}
1367		1480
1368	our $_sig_name_init; $_sig_name_init = sub {	1481	our $_sig_name_init; $_sig_name_init = sub {
1369	eval q{ # poor man's autoloading	1482	eval q{ # poor man's autoloading {}
1370	undef $_sig_name_init;	1483	undef $_sig_name_init;
1371		1484
1372	if (_have_async_interrupt) {	1485	if (_have_async_interrupt) {
1373	*sig2num = \&Async::Interrupt::sig2num;	1486	*sig2num = \&Async::Interrupt::sig2num;
1374	*sig2name = \&Async::Interrupt::sig2name;	1487	*sig2name = \&Async::Interrupt::sig2name;
…		…
1401	# probe for availability of Async::Interrupt	1514	# probe for availability of Async::Interrupt
1402	if (_have_async_interrupt) {	1515	if (_have_async_interrupt) {
1403	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;	1516	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1404		1517
1405	$SIGPIPE_R = new Async::Interrupt::EventPipe;	1518	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1406	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);	1519	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1407		1520
1408	} else {	1521	} else {
1409	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;	1522	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1410
1411	require Fcntl;
1412		1523
1413	if (AnyEvent::WIN32) {	1524	if (AnyEvent::WIN32) {
1414	require AnyEvent::Util;	1525	require AnyEvent::Util;
1415		1526
1416	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();	1527	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1417	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;	1528	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1418	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case	1529	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1419	} else {	1530	} else {
1420	pipe $SIGPIPE_R, $SIGPIPE_W;	1531	pipe $SIGPIPE_R, $SIGPIPE_W;
1421	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1532	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1422	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1533	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1423		1534
1424	# not strictly required, as $^F is normally 2, but let's make sure...	1535	# not strictly required, as $^F is normally 2, but let's make sure...
1425	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1536	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1426	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1537	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1427	}	1538	}
1428		1539
1429	$SIGPIPE_R	1540	$SIGPIPE_R
1430	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1541	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1431		1542
1432	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1543	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1433	}	1544	}
1434		1545
1435	*signal = sub {	1546	*signal = $HAVE_ASYNC_INTERRUPT
		1547	? sub {
1436	my (undef, %arg) = @_;	1548	my (undef, %arg) = @_;
1437		1549
1438	my $signal = uc $arg{signal}
1439	or Carp::croak "required option 'signal' is missing";
1440
1441	if ($HAVE_ASYNC_INTERRUPT) {
1442	# async::interrupt	1550	# async::interrupt
1443
1444	$signal = sig2num $signal;	1551	my $signal = sig2num $arg{signal};
1445	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1552	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1446		1553
1447	$SIG_ASY{$signal} ||= new Async::Interrupt	1554	$SIG_ASY{$signal} ||= new Async::Interrupt
1448	cb => sub { undef $SIG_EV{$signal} },	1555	cb => sub { undef $SIG_EV{$signal} },
1449	signal => $signal,	1556	signal => $signal,
1450	pipe => [$SIGPIPE_R->filenos],	1557	pipe => [$SIGPIPE_R->filenos],
1451	pipe_autodrain => 0,	1558	pipe_autodrain => 0,
1452	;	1559	;
1453		1560
1454	} else {	1561	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1562	}
		1563	: sub {
		1564	my (undef, %arg) = @_;
		1565
1455	# pure perl	1566	# pure perl
1456
1457	# AE::Util has been loaded in signal
1458	$signal = sig2name $signal;	1567	my $signal = sig2name $arg{signal};
1459	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1568	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1460		1569
1461	$SIG{$signal} ||= sub {	1570	$SIG{$signal} ||= sub {
1462	local $!;	1571	local $!;
1463	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1572	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1464	undef $SIG_EV{$signal};	1573	undef $SIG_EV{$signal};
1465	};	1574	};
1466		1575
1467	# can't do signal processing without introducing races in pure perl,	1576	# can't do signal processing without introducing races in pure perl,
1468	# so limit the signal latency.	1577	# so limit the signal latency.
1469	_sig_add;	1578	_sig_add;
1470	}
1471		1579
1472	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1580	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1581	}
1473	};	1582	;
1474		1583
1475	*AnyEvent::Base::signal::DESTROY = sub {	1584	*AnyEvent::Base::signal::DESTROY = sub {
1476	my ($signal, $cb) = @{$_[0]};	1585	my ($signal, $cb) = @{$_[0]};
1477		1586
1478	_sig_del;	1587	_sig_del;
…		…
1485	# print weird messages, or just unconditionally exit	1594	# print weird messages, or just unconditionally exit
1486	# instead of getting the default action.	1595	# instead of getting the default action.
1487	undef $SIG{$signal}	1596	undef $SIG{$signal}
1488	unless keys %{ $SIG_CB{$signal} };	1597	unless keys %{ $SIG_CB{$signal} };
1489	};	1598	};
		1599
		1600	*_signal_exec = sub {
		1601	$HAVE_ASYNC_INTERRUPT
		1602	? $SIGPIPE_R->drain
		1603	: sysread $SIGPIPE_R, (my $dummy), 9;
		1604
		1605	while (%SIG_EV) {
		1606	for (keys %SIG_EV) {
		1607	delete $SIG_EV{$_};
		1608	$_->() for values %{ $SIG_CB{$_} || {} };
		1609	}
		1610	}
		1611	};
1490	};	1612	};
1491	die if $@;	1613	die if $@;
		1614
1492	&signal	1615	&signal
1493	}	1616	}
1494		1617
1495	# default implementation for ->child	1618	# default implementation for ->child
1496		1619
1497	our %PID_CB;	1620	our %PID_CB;
1498	our $CHLD_W;	1621	our $CHLD_W;
1499	our $CHLD_DELAY_W;	1622	our $CHLD_DELAY_W;
1500	our $WNOHANG;
1501		1623
		1624	# used by many Impl's
1502	sub _emit_childstatus($$) {	1625	sub _emit_childstatus($$) {
1503	my (undef, $rpid, $rstatus) = @_;	1626	my (undef, $rpid, $rstatus) = @_;
1504		1627
1505	$_->($rpid, $rstatus)	1628	$_->($rpid, $rstatus)
1506	for values %{ $PID_CB{$rpid} || {} },	1629	for values %{ $PID_CB{$rpid} || {} },
1507	values %{ $PID_CB{0} || {} };	1630	values %{ $PID_CB{0} || {} };
1508	}	1631	}
1509		1632
1510	sub _sigchld {
1511	my $pid;
1512
1513	AnyEvent->_emit_childstatus ($pid, $?)
1514	while ($pid = waitpid -1, $WNOHANG) > 0;
1515	}
1516
1517	sub child {	1633	sub child {
		1634	eval q{ # poor man's autoloading {}
		1635	*_sigchld = sub {
		1636	my $pid;
		1637
		1638	AnyEvent->_emit_childstatus ($pid, $?)
		1639	while ($pid = waitpid -1, WNOHANG) > 0;
		1640	};
		1641
		1642	*child = sub {
1518	my (undef, %arg) = @_;	1643	my (undef, %arg) = @_;
1519		1644
1520	defined (my $pid = $arg{pid} + 0)	1645	defined (my $pid = $arg{pid} + 0)
1521	or Carp::croak "required option 'pid' is missing";	1646	or Carp::croak "required option 'pid' is missing";
1522		1647
1523	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1648	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1524		1649
1525	# WNOHANG is almost cetrainly 1 everywhere
1526	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1527	? 1
1528	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1529
1530	unless ($CHLD_W) {	1650	unless ($CHLD_W) {
1531	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1651	$CHLD_W = AE::signal CHLD => \&_sigchld;
1532	# child could be a zombie already, so make at least one round	1652	# child could be a zombie already, so make at least one round
1533	&_sigchld;	1653	&_sigchld;
1534	}	1654	}
1535		1655
1536	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1656	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1537	}	1657	};
1538		1658
1539	sub AnyEvent::Base::child::DESTROY {	1659	*AnyEvent::Base::child::DESTROY = sub {
1540	my ($pid, $cb) = @{$_[0]};	1660	my ($pid, $cb) = @{$_[0]};
1541		1661
1542	delete $PID_CB{$pid}{$cb};	1662	delete $PID_CB{$pid}{$cb};
1543	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1663	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1544		1664
1545	undef $CHLD_W unless keys %PID_CB;	1665	undef $CHLD_W unless keys %PID_CB;
		1666	};
		1667	};
		1668	die if $@;
		1669
		1670	&child
1546	}	1671	}
1547		1672
1548	# idle emulation is done by simply using a timer, regardless	1673	# idle emulation is done by simply using a timer, regardless
1549	# of whether the process is idle or not, and not letting	1674	# of whether the process is idle or not, and not letting
1550	# the callback use more than 50% of the time.	1675	# the callback use more than 50% of the time.
1551	sub idle {	1676	sub idle {
		1677	eval q{ # poor man's autoloading {}
		1678	*idle = sub {
1552	my (undef, %arg) = @_;	1679	my (undef, %arg) = @_;
1553		1680
1554	my ($cb, $w, $rcb) = $arg{cb};	1681	my ($cb, $w, $rcb) = $arg{cb};
1555		1682
1556	$rcb = sub {	1683	$rcb = sub {
1557	if ($cb) {	1684	if ($cb) {
1558	$w = _time;	1685	$w = _time;
1559	&$cb;	1686	&$cb;
1560	$w = _time - $w;	1687	$w = _time - $w;
1561		1688
1562	# never use more then 50% of the time for the idle watcher,	1689	# never use more then 50% of the time for the idle watcher,
1563	# within some limits	1690	# within some limits
1564	$w = 0.0001 if $w < 0.0001;	1691	$w = 0.0001 if $w < 0.0001;
1565	$w = 5 if $w > 5;	1692	$w = 5 if $w > 5;
1566		1693
1567	$w = AnyEvent->timer (after => $w, cb => $rcb);	1694	$w = AE::timer $w, 0, $rcb;
1568	} else {	1695	} else {
1569	# clean up...	1696	# clean up...
1570	undef $w;	1697	undef $w;
1571	undef $rcb;	1698	undef $rcb;
		1699	}
		1700	};
		1701
		1702	$w = AE::timer 0.05, 0, $rcb;
		1703
		1704	bless \\$cb, "AnyEvent::Base::idle"
1572	}	1705	};
		1706
		1707	*AnyEvent::Base::idle::DESTROY = sub {
		1708	undef $${$_[0]};
		1709	};
1573	};	1710	};
		1711	die if $@;
1574		1712
1575	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1713	&idle
1576
1577	bless \\$cb, "AnyEvent::Base::idle"
1578	}
1579
1580	sub AnyEvent::Base::idle::DESTROY {
1581	undef $${$_[0]};
1582	}	1714	}
1583		1715
1584	package AnyEvent::CondVar;	1716	package AnyEvent::CondVar;
1585		1717
1586	our @ISA = AnyEvent::CondVar::Base::;	1718	our @ISA = AnyEvent::CondVar::Base::;
		1719
		1720	# only to be used for subclassing
		1721	sub new {
		1722	my $class = shift;
		1723	bless AnyEvent->condvar (@_), $class
		1724	}
1587		1725
1588	package AnyEvent::CondVar::Base;	1726	package AnyEvent::CondVar::Base;
1589		1727
1590	#use overload	1728	#use overload
1591	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1729	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
…		…
1601		1739
1602	sub _send {	1740	sub _send {
1603	# nop	1741	# nop
1604	}	1742	}
1605		1743
		1744	sub _wait {
		1745	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1746	}
		1747
1606	sub send {	1748	sub send {
1607	my $cv = shift;	1749	my $cv = shift;
1608	$cv->{_ae_sent} = [@_];	1750	$cv->{_ae_sent} = [@_];
1609	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};	1751	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1610	$cv->_send;	1752	$cv->_send;
…		…
1617		1759
1618	sub ready {	1760	sub ready {
1619	$_[0]{_ae_sent}	1761	$_[0]{_ae_sent}
1620	}	1762	}
1621		1763
1622	sub _wait {
1623	$WAITING
1624	and !$_[0]{_ae_sent}
1625	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1626
1627	local $WAITING = 1;
1628	AnyEvent->one_event while !$_[0]{_ae_sent};
1629	}
1630
1631	sub recv {	1764	sub recv {
		1765	unless ($_[0]{_ae_sent}) {
		1766	$WAITING
		1767	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1768
		1769	local $WAITING = 1;
1632	$_[0]->_wait;	1770	$_[0]->_wait;
		1771	}
1633		1772
1634	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1773	$_[0]{_ae_croak}
1635	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1774	and Carp::croak $_[0]{_ae_croak};
		1775
		1776	wantarray
		1777	? @{ $_[0]{_ae_sent} }
		1778	: $_[0]{_ae_sent}[0]
1636	}	1779	}
1637		1780
1638	sub cb {	1781	sub cb {
1639	my $cv = shift;	1782	my $cv = shift;
1640		1783
…		…
1656	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	1799	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1657	}	1800	}
1658		1801
1659	# undocumented/compatibility with pre-3.4	1802	# undocumented/compatibility with pre-3.4
1660	*broadcast = \&send;	1803	*broadcast = \&send;
1661	*wait = \&_wait;	1804	*wait = \&recv;
1662
1663	#############################################################################
1664	# "new" API, currently only emulation of it
1665	#############################################################################
1666
1667	package AE;
1668
1669	sub io($$$) {
1670	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1671	}
1672
1673	sub timer($$$) {
1674	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2]);
1675	}
1676
1677	sub signal($$) {
1678	AnyEvent->signal (signal => $_[0], cb => $_[1]);
1679	}
1680
1681	sub child($$) {
1682	AnyEvent->child (pid => $_[0], cb => $_[1]);
1683	}
1684
1685	sub idle($) {
1686	AnyEvent->idle (cb => $_[0]);
1687	}
1688
1689	sub cv() {
1690	AnyEvent->condvar
1691	}
1692
1693	sub now() {
1694	AnyEvent->now
1695	}
1696
1697	sub now_update() {
1698	AnyEvent->now_update
1699	}
1700
1701	sub time() {
1702	AnyEvent->time
1703	}
1704		1805
1705	=head1 ERROR AND EXCEPTION HANDLING	1806	=head1 ERROR AND EXCEPTION HANDLING
1706		1807
1707	In general, AnyEvent does not do any error handling - it relies on the	1808	In general, AnyEvent does not do any error handling - it relies on the
1708	caller to do that if required. The L<AnyEvent::Strict> module (see also	1809	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1755	check the arguments passed to most method calls. If it finds any problems,	1856	check the arguments passed to most method calls. If it finds any problems,
1756	it will croak.	1857	it will croak.
1757		1858
1758	In other words, enables "strict" mode.	1859	In other words, enables "strict" mode.
1759		1860
1760	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	1861	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	1862	>>, it is definitely recommended to keep it off in production. Keeping
1762	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	1863	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1763	can be very useful, however.	1864	can be very useful, however.
1764		1865
1765	=item C<PERL_ANYEVENT_MODEL>	1866	=item C<PERL_ANYEVENT_MODEL>
…		…
1902	warn "read: $input\n"; # output what has been read	2003	warn "read: $input\n"; # output what has been read
1903	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2004	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1904	},	2005	},
1905	);	2006	);
1906		2007
1907	my $time_watcher; # can only be used once
1908
1909	sub new_timer {
1910	$timer = AnyEvent->timer (after => 1, cb => sub {	2008	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1911	warn "timeout\n"; # print 'timeout' about every second	2009	warn "timeout\n"; # print 'timeout' at most every second
1912	&new_timer; # and restart the time
1913	});	2010	});
1914	}
1915
1916	new_timer; # create first timer
1917		2011
1918	$cv->recv; # wait until user enters /^q/i	2012	$cv->recv; # wait until user enters /^q/i
1919		2013
1920	=head1 REAL-WORLD EXAMPLE	2014	=head1 REAL-WORLD EXAMPLE
1921		2015
…		…
1994		2088
1995	The actual code goes further and collects all errors (C<die>s, exceptions)	2089	The actual code goes further and collects all errors (C<die>s, exceptions)
1996	that occurred during request processing. The C<result> method detects	2090	that occurred during request processing. The C<result> method detects
1997	whether an exception as thrown (it is stored inside the $txn object)	2091	whether an exception as thrown (it is stored inside the $txn object)
1998	and just throws the exception, which means connection errors and other	2092	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	2093	problems get reported to the code that tries to use the result, not in a
2000	random callback.	2094	random callback.
2001		2095
2002	All of this enables the following usage styles:	2096	All of this enables the following usage styles:
2003		2097
2004	1. Blocking:	2098	1. Blocking:
…		…
2052	through AnyEvent. The benchmark creates a lot of timers (with a zero	2146	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,	2147	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.	2148	which it is), lets them fire exactly once and destroys them again.
2055		2149
2056	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2150	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
2057	distribution.	2151	distribution. It uses the L<AE> interface, which makes a real difference
		2152	for the EV and Perl backends only.
2058		2153
2059	=head3 Explanation of the columns	2154	=head3 Explanation of the columns
2060		2155
2061	I<watcher> is the number of event watchers created/destroyed. Since	2156	I<watcher> is the number of event watchers created/destroyed. Since
2062	different event models feature vastly different performances, each event	2157	different event models feature vastly different performances, each event
…		…
2083	watcher.	2178	watcher.
2084		2179
2085	=head3 Results	2180	=head3 Results
2086		2181
2087	name watchers bytes create invoke destroy comment	2182	name watchers bytes create invoke destroy comment
2088	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2183	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	2184	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	2185	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	2186	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	2187	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	2188	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	2189	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	2190	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	2191	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	2192	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	2193	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	2194	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
2100		2195
2101	=head3 Discussion	2196	=head3 Discussion
2102		2197
2103	The benchmark does I<not> measure scalability of the event loop very	2198	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)	2199	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	2211	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	2212	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
2118	cycles with POE.	2213	cycles with POE.
2119		2214
2120	C<EV> is the sole leader regarding speed and memory use, which are both	2215	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	2216	maximal/minimal, respectively. When using the L<AE> API there is zero
		2217	overhead (when going through the AnyEvent API create is about 5-6 times
		2218	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	2219	any other event loop and is still faster than Event natively).
2123	natively.
2124		2220
2125	The pure perl implementation is hit in a few sweet spots (both the	2221	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	2222	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	2223	interpreter and the backend itself). Nevertheless this shows that it
2128	adds very little overhead in itself. Like any select-based backend its	2224	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	2298	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	2299	(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.	2300	connections, most of which are idle at any one point in time.
2205		2301
2206	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2302	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2207	distribution.	2303	distribution. It uses the L<AE> interface, which makes a real difference
		2304	for the EV and Perl backends only.
2208		2305
2209	=head3 Explanation of the columns	2306	=head3 Explanation of the columns
2210		2307
2211	I<sockets> is the number of sockets, and twice the number of "servers" (as	2308	I<sockets> is the number of sockets, and twice the number of "servers" (as
2212	each server has a read and write socket end).	2309	each server has a read and write socket end).
…		…
2220	a new one that moves the timeout into the future.	2317	a new one that moves the timeout into the future.
2221		2318
2222	=head3 Results	2319	=head3 Results
2223		2320
2224	name sockets create request	2321	name sockets create request
2225	EV 20000 69.01 11.16	2322	EV 20000 62.66 7.99
2226	Perl 20000 73.32 35.87	2323	Perl 20000 68.32 32.64
2227	IOAsync 20000 157.00 98.14 epoll	2324	IOAsync 20000 174.06 101.15 epoll
2228	IOAsync 20000 159.31 616.06 poll	2325	IOAsync 20000 174.67 610.84 poll
2229	Event 20000 212.62 257.32	2326	Event 20000 202.69 242.91
2230	Glib 20000 651.16 1896.30	2327	Glib 20000 557.01 1689.52
2231	POE 20000 349.67 12317.24 uses POE::Loop::Event	2328	POE 20000 341.54 12086.32 uses POE::Loop::Event
2232		2329
2233	=head3 Discussion	2330	=head3 Discussion
2234		2331
2235	This benchmark I<does> measure scalability and overall performance of the	2332	This benchmark I<does> measure scalability and overall performance of the
2236	particular event loop.	2333	particular event loop.
…		…
2362	As you can see, the AnyEvent + EV combination even beats the	2459	As you can see, the AnyEvent + EV combination even beats the
2363	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2460	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2364	backend easily beats IO::Lambda and POE.	2461	backend easily beats IO::Lambda and POE.
2365		2462
2366	And even the 100% non-blocking version written using the high-level (and	2463	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	2464	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	2465	higher level ("unoptimised") abstractions by a large margin, even though
2369	in a non-blocking way.	2466	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2370		2467
2371	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2468	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	2469	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.	2470	part of the IO::Lambda distribution and were used without any changes.
2374		2471
2375		2472
2376	=head1 SIGNALS	2473	=head1 SIGNALS
2377		2474
2378	AnyEvent currently installs handlers for these signals:	2475	AnyEvent currently installs handlers for these signals:
…		…
2415	unless defined $SIG{PIPE};	2512	unless defined $SIG{PIPE};
2416		2513
2417	=head1 RECOMMENDED/OPTIONAL MODULES	2514	=head1 RECOMMENDED/OPTIONAL MODULES
2418		2515
2419	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2516	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2420	it's built-in modules) are required to use it.	2517	its built-in modules) are required to use it.
2421		2518
2422	That does not mean that AnyEvent won't take advantage of some additional	2519	That does not mean that AnyEvent won't take advantage of some additional
2423	modules if they are installed.	2520	modules if they are installed.
2424		2521
2425	This section epxlains which additional modules will be used, and how they	2522	This section explains which additional modules will be used, and how they
2426	affect AnyEvent's operetion.	2523	affect AnyEvent's operation.
2427		2524
2428	=over 4	2525	=over 4
2429		2526
2430	=item L<Async::Interrupt>	2527	=item L<Async::Interrupt>
2431		2528
…		…
2436	catch the signals) with some delay (default is 10 seconds, look for	2533	catch the signals) with some delay (default is 10 seconds, look for
2437	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2534	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2438		2535
2439	If this module is available, then it will be used to implement signal	2536	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	2537	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	2538	will not be interrupted regularly, which is more efficient (and good for
2442	battery life on laptops).	2539	battery life on laptops).
2443		2540
2444	This affects not just the pure-perl event loop, but also other event loops	2541	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).	2542	that have no signal handling on their own (e.g. Glib, Tk, Qt).
2446		2543
…		…
2458	automatic timer adjustments even when no monotonic clock is available,	2555	automatic timer adjustments even when no monotonic clock is available,
2459	can take avdantage of advanced kernel interfaces such as C<epoll> and	2556	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	2557	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>).	2558	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2462		2559
		2560	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2561	then this module will do nothing for you.
		2562
2463	=item L<Guard>	2563	=item L<Guard>
2464		2564
2465	The guard module, when used, will be used to implement	2565	The guard module, when used, will be used to implement
2466	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2566	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	2567	lot less memory), but otherwise doesn't affect guard operation much. It is
2468	purely used for performance.	2568	purely used for performance.
2469		2569
2470	=item L<JSON> and L<JSON::XS>	2570	=item L<JSON> and L<JSON::XS>
2471		2571
2472	This module is required when you want to read or write JSON data via	2572	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	2573	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.	2574	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		2575
2479	=item L<Net::SSLeay>	2576	=item L<Net::SSLeay>
2480		2577
2481	Implementing TLS/SSL in Perl is certainly interesting, but not very	2578	Implementing TLS/SSL in Perl is certainly interesting, but not very
2482	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2579	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.	2580	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2484		2581
2485	=item L<Time::HiRes>	2582	=item L<Time::HiRes>
2486		2583
2487	This module is part of perl since release 5.008. It will be used when the	2584	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	2585	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	2586	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
2490	try to use a monotonic clock for timing stability.	2587	try to use a monotonic clock for timing stability.
2491		2588
2492	=back	2589	=back
2493		2590
2494		2591
2495	=head1 FORK	2592	=head1 FORK
2496		2593
2497	Most event libraries are not fork-safe. The ones who are usually are	2594	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>	2595	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2499	calls. Only L<EV> is fully fork-aware.	2596	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2597	are usually badly thought-out hacks that are incompatible with fork in
		2598	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2599	continue event-processing in both parent and child (or both, if you know
		2600	what you are doing).
		2601
		2602	This means that, in general, you cannot fork and do event processing in
		2603	the child if the event library was initialised before the fork (which
		2604	usually happens when the first AnyEvent watcher is created, or the library
		2605	is loaded).
2500		2606
2501	If you have to fork, you must either do so I<before> creating your first	2607	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	2608	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.	2609	something completely out of the scope of AnyEvent.
		2610
		2611	The problem of doing event processing in the parent I<and> the child
		2612	is much more complicated: even for backends that I<are> fork-aware or
		2613	fork-safe, their behaviour is not usually what you want: fork clones all
		2614	watchers, that means all timers, I/O watchers etc. are active in both
		2615	parent and child, which is almost never what you want. USing C<exec>
		2616	to start worker children from some kind of manage rprocess is usually
		2617	preferred, because it is much easier and cleaner, at the expense of having
		2618	to have another binary.
2504		2619
2505		2620
2506	=head1 SECURITY CONSIDERATIONS	2621	=head1 SECURITY CONSIDERATIONS
2507		2622
2508	AnyEvent can be forced to load any event model via	2623	AnyEvent can be forced to load any event model via
…		…
2538	pronounced).	2653	pronounced).
2539		2654
2540		2655
2541	=head1 SEE ALSO	2656	=head1 SEE ALSO
2542		2657
		2658	Tutorial/Introduction: L<AnyEvent::Intro>.
		2659
		2660	FAQ: L<AnyEvent::FAQ>.
		2661
2543	Utility functions: L<AnyEvent::Util>.	2662	Utility functions: L<AnyEvent::Util>.
2544		2663
2545	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2664	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
2546	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2665	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2547		2666
…		…
2553	Non-blocking file handles, sockets, TCP clients and	2672	Non-blocking file handles, sockets, TCP clients and
2554	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2673	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2555		2674
2556	Asynchronous DNS: L<AnyEvent::DNS>.	2675	Asynchronous DNS: L<AnyEvent::DNS>.
2557		2676
2558	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	2677	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2559	L<Coro::Event>,
2560		2678
2561	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	2679	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2562	L<AnyEvent::HTTP>.	2680	L<AnyEvent::HTTP>.
2563		2681
2564		2682
2565	=head1 AUTHOR	2683	=head1 AUTHOR
2566		2684

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