[ViewVC] Diff of: cvs/AnyEvent/lib/AnyEvent.pm

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.107 by root, Tue May 6 12:15:50 2008 UTC vs.
Revision 1.143 by root, Wed May 28 23:57:38 2008 UTC

…		…
1	=head1 NAME	1	=head1 => NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - provide framework for multiple event loops
4		4
5	EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops
6		6
7	=head1 SYNOPSIS	7	=head1 SYNOPSIS
8		8
9	use AnyEvent;	9	use AnyEvent;
10		10
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	15	my $w = AnyEvent->timer (after => $seconds, cb => sub {
16	...	16	...
17	});	17	});
18		18
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	19	my $w = AnyEvent->condvar; # stores whether a condition was flagged
		20	$w->send; # wake up current and all future recv's
20	$w->wait; # enters "main loop" till $condvar gets ->send	21	$w->recv; # enters "main loop" till $condvar gets ->send
21	$w->send; # wake up current and all future wait's
22		22
23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24		24
25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26	nowadays. So what is different about AnyEvent?	26	nowadays. So what is different about AnyEvent?
…		…
48	isn't itself. What's worse, all the potential users of your module are	48	isn't itself. What's worse, all the potential users of your module are
49	I<also> forced to use the same event loop you use.	49	I<also> forced to use the same event loop you use.
50		50
51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
53	with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if	53	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
54	your module uses one of those, every user of your module has to use it,	54	your module uses one of those, every user of your module has to use it,
55	too. But if your module uses AnyEvent, it works transparently with all	55	too. But if your module uses AnyEvent, it works transparently with all
56	event models it supports (including stuff like POE and IO::Async, as long	56	event models it supports (including stuff like POE and IO::Async, as long
57	as those use one of the supported event loops. It is trivial to add new	57	as those use one of the supported event loops. It is trivial to add new
58	event loops to AnyEvent, too, so it is future-proof).	58	event loops to AnyEvent, too, so it is future-proof).
59		59
60	In addition to being free of having to use I<the one and only true event	60	In addition to being free of having to use I<the one and only true event
61	model>, AnyEvent also is free of bloat and policy: with POE or similar	61	model>, AnyEvent also is free of bloat and policy: with POE or similar
62	modules, you get an enourmous amount of code and strict rules you have to	62	modules, you get an enormous amount of code and strict rules you have to
63	follow. AnyEvent, on the other hand, is lean and up to the point, by only	63	follow. AnyEvent, on the other hand, is lean and up to the point, by only
64	offering the functionality that is necessary, in as thin as a wrapper as	64	offering the functionality that is necessary, in as thin as a wrapper as
65	technically possible.	65	technically possible.
66		66
		67	Of course, AnyEvent comes with a big (and fully optional!) toolbox
		68	of useful functionality, such as an asynchronous DNS resolver, 100%
		69	non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
		70	such as Windows) and lots of real-world knowledge and workarounds for
		71	platform bugs and differences.
		72
67	Of course, if you want lots of policy (this can arguably be somewhat	73	Now, if you I<do want> lots of policy (this can arguably be somewhat
68	useful) and you want to force your users to use the one and only event	74	useful) and you want to force your users to use the one and only event
69	model, you should I<not> use this module.	75	model, you should I<not> use this module.
70		76
71	=head1 DESCRIPTION	77	=head1 DESCRIPTION
72		78
…		…
78	The interface itself is vaguely similar, but not identical to the L<Event>	84	The interface itself is vaguely similar, but not identical to the L<Event>
79	module.	85	module.
80		86
81	During the first call of any watcher-creation method, the module tries	87	During the first call of any watcher-creation method, the module tries
82	to detect the currently loaded event loop by probing whether one of the	88	to detect the currently loaded event loop by probing whether one of the
83	following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>,	89	following modules is already loaded: L<EV>,
84	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	90	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,
85	L<POE>. The first one found is used. If none are found, the module tries	91	L<POE>. The first one found is used. If none are found, the module tries
86	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	92	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl
87	adaptor should always succeed) in the order given. The first one that can	93	adaptor should always succeed) in the order given. The first one that can
88	be successfully loaded will be used. If, after this, still none could be	94	be successfully loaded will be used. If, after this, still none could be
…		…
102	starts using it, all bets are off. Maybe you should tell their authors to	108	starts using it, all bets are off. Maybe you should tell their authors to
103	use AnyEvent so their modules work together with others seamlessly...	109	use AnyEvent so their modules work together with others seamlessly...
104		110
105	The pure-perl implementation of AnyEvent is called	111	The pure-perl implementation of AnyEvent is called
106	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	112	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
107	explicitly.	113	explicitly and enjoy the high availability of that event loop :)
108		114
109	=head1 WATCHERS	115	=head1 WATCHERS
110		116
111	AnyEvent has the central concept of a I<watcher>, which is an object that	117	AnyEvent has the central concept of a I<watcher>, which is an object that
112	stores relevant data for each kind of event you are waiting for, such as	118	stores relevant data for each kind of event you are waiting for, such as
113	the callback to call, the filehandle to watch, etc.	119	the callback to call, the file handle to watch, etc.
114		120
115	These watchers are normal Perl objects with normal Perl lifetime. After	121	These watchers are normal Perl objects with normal Perl lifetime. After
116	creating a watcher it will immediately "watch" for events and invoke the	122	creating a watcher it will immediately "watch" for events and invoke the
117	callback when the event occurs (of course, only when the event model	123	callback when the event occurs (of course, only when the event model
118	is in control).	124	is in control).
…		…
227	timers.	233	timers.
228		234
229	AnyEvent always prefers relative timers, if available, matching the	235	AnyEvent always prefers relative timers, if available, matching the
230	AnyEvent API.	236	AnyEvent API.
231		237
		238	AnyEvent has two additional methods that return the "current time":
		239
		240	=over 4
		241
		242	=item AnyEvent->time
		243
		244	This returns the "current wallclock time" as a fractional number of
		245	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
		246	return, and the result is guaranteed to be compatible with those).
		247
		248	It progresses independently of any event loop processing.
		249
		250	In almost all cases (in all cases if you don't care), this is the function
		251	to call when you want to know the current time.
		252
		253	=item AnyEvent->now
		254
		255	This also returns the "current wallclock time", but unlike C<time>, above,
		256	this value might change only once per event loop iteration, depending on
		257	the event loop (most return the same time as C<time>, above). This is the
		258	time that AnyEvent timers get scheduled against.
		259
		260	For a practical example of when these times differ, consider L<Event::Lib>
		261	and L<EV> and the following set-up:
		262
		263	The event loop is running and has just invoked one of your callback at
		264	time=500 (assume no other callbacks delay processing). In your callback,
		265	you wait a second by executing C<sleep 1> (blocking the process for a
		266	second) and then (at time=501) you create a relative timer that fires
		267	after three seconds.
		268
		269	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
		270	both return C<501>, because that is the current time, and the timer will
		271	be scheduled to fire at time=504 (C<501> + C<3>).
		272
		273	With L<EV>m C<< AnyEvent->time >> returns C<501> (as that is the current
		274	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
		275	last event processing phase started. With L<EV>, your timer gets scheduled
		276	to run at time=503 (C<500> + C<3>).
		277
		278	In one sense, L<Event::Lib> is more exact, as it uses the current time
		279	regardless of any delays introduced by event processing. However, most
		280	callbacks do not expect large delays in processing, so this causes a
		281	higher drift (and a lot more syscalls to get the current time).
		282
		283	In another sense, L<EV> is more exact, as your timer will be scheduled at
		284	the same time, regardless of how long event processing actually took.
		285
		286	In either case, if you care (and in most cases, you don't), then you
		287	can get whatever behaviour you want with any event loop, by taking the
		288	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
		289	account.
		290
		291	=back
		292
232	=head2 SIGNAL WATCHERS	293	=head2 SIGNAL WATCHERS
233		294
234	You can watch for signals using a signal watcher, C<signal> is the signal	295	You can watch for signals using a signal watcher, C<signal> is the signal
235	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to	296	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to
236	be invoked whenever a signal occurs.	297	be invoked whenever a signal occurs.
237		298
238	Although the callback might get passed parameters, their value and	299	Although the callback might get passed parameters, their value and
239	presence is undefined and you cannot rely on them. Portable AnyEvent	300	presence is undefined and you cannot rely on them. Portable AnyEvent
240	callbacks cannot use arguments passed to signal watcher callbacks.	301	callbacks cannot use arguments passed to signal watcher callbacks.
241		302
242	Multiple signal occurances can be clumped together into one callback	303	Multiple signal occurrences can be clumped together into one callback
243	invocation, and callback invocation will be synchronous. synchronous means	304	invocation, and callback invocation will be synchronous. Synchronous means
244	that it might take a while until the signal gets handled by the process,	305	that it might take a while until the signal gets handled by the process,
245	but it is guarenteed not to interrupt any other callbacks.	306	but it is guaranteed not to interrupt any other callbacks.
246		307
247	The main advantage of using these watchers is that you can share a signal	308	The main advantage of using these watchers is that you can share a signal
248	between multiple watchers.	309	between multiple watchers.
249		310
250	This watcher might use C<%SIG>, so programs overwriting those signals	311	This watcher might use C<%SIG>, so programs overwriting those signals
…		…
278	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	339	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
279		340
280	Example: fork a process and wait for it	341	Example: fork a process and wait for it
281		342
282	my $done = AnyEvent->condvar;	343	my $done = AnyEvent->condvar;
283
284	AnyEvent::detect; # force event module to be initialised
285		344
286	my $pid = fork or exit 5;	345	my $pid = fork or exit 5;
287		346
288	my $w = AnyEvent->child (	347	my $w = AnyEvent->child (
289	pid => $pid,	348	pid => $pid,
…		…
293	$done->send;	352	$done->send;
294	},	353	},
295	);	354	);
296		355
297	# do something else, then wait for process exit	356	# do something else, then wait for process exit
298	$done->wait;	357	$done->recv;
299		358
300	=head2 CONDITION VARIABLES	359	=head2 CONDITION VARIABLES
301		360
302	If you are familiar with some event loops you will know that all of them	361	If you are familiar with some event loops you will know that all of them
303	require you to run some blocking "loop", "run" or similar function that	362	require you to run some blocking "loop", "run" or similar function that
…		…
312	Condition variables can be created by calling the C<< AnyEvent->condvar	371	Condition variables can be created by calling the C<< AnyEvent->condvar
313	>> method, usually without arguments. The only argument pair allowed is	372	>> method, usually without arguments. The only argument pair allowed is
314	C<cb>, which specifies a callback to be called when the condition variable	373	C<cb>, which specifies a callback to be called when the condition variable
315	becomes true.	374	becomes true.
316		375
317	After creation, the conditon variable is "false" until it becomes "true"	376	After creation, the condition variable is "false" until it becomes "true"
318	by calling the C<send> method.	377	by calling the C<send> method (or calling the condition variable as if it
		378	were a callback, read about the caveats in the description for the C<<
		379	->send >> method).
319		380
320	Condition variables are similar to callbacks, except that you can	381	Condition variables are similar to callbacks, except that you can
321	optionally wait for them. They can also be called merge points - points	382	optionally wait for them. They can also be called merge points - points
322	in time where multiple outstandign events have been processed. And yet	383	in time where multiple outstanding events have been processed. And yet
323	another way to call them is transations - each condition variable can be	384	another way to call them is transactions - each condition variable can be
324	used to represent a transaction, which finishes at some point and delivers	385	used to represent a transaction, which finishes at some point and delivers
325	a result.	386	a result.
326		387
327	Condition variables are very useful to signal that something has finished,	388	Condition variables are very useful to signal that something has finished,
328	for example, if you write a module that does asynchronous http requests,	389	for example, if you write a module that does asynchronous http requests,
329	then a condition variable would be the ideal candidate to signal the	390	then a condition variable would be the ideal candidate to signal the
330	availability of results. The user can either act when the callback is	391	availability of results. The user can either act when the callback is
331	called or can synchronously C<< ->wait >> for the results.	392	called or can synchronously C<< ->recv >> for the results.
332		393
333	You can also use them to simulate traditional event loops - for example,	394	You can also use them to simulate traditional event loops - for example,
334	you can block your main program until an event occurs - for example, you	395	you can block your main program until an event occurs - for example, you
335	could C<< ->wait >> in your main program until the user clicks the Quit	396	could C<< ->recv >> in your main program until the user clicks the Quit
336	button of your app, which would C<< ->send >> the "quit" event.	397	button of your app, which would C<< ->send >> the "quit" event.
337		398
338	Note that condition variables recurse into the event loop - if you have	399	Note that condition variables recurse into the event loop - if you have
339	two pieces of code that call C<< ->wait >> in a round-robbin fashion, you	400	two pieces of code that call C<< ->recv >> in a round-robin fashion, you
340	lose. Therefore, condition variables are good to export to your caller, but	401	lose. Therefore, condition variables are good to export to your caller, but
341	you should avoid making a blocking wait yourself, at least in callbacks,	402	you should avoid making a blocking wait yourself, at least in callbacks,
342	as this asks for trouble.	403	as this asks for trouble.
343		404
344	Condition variables are represented by hash refs in perl, and the keys	405	Condition variables are represented by hash refs in perl, and the keys
…		…
349		410
350	There are two "sides" to a condition variable - the "producer side" which	411	There are two "sides" to a condition variable - the "producer side" which
351	eventually calls C<< -> send >>, and the "consumer side", which waits	412	eventually calls C<< -> send >>, and the "consumer side", which waits
352	for the send to occur.	413	for the send to occur.
353		414
354	Example:	415	Example: wait for a timer.
355		416
356	# wait till the result is ready	417	# wait till the result is ready
357	my $result_ready = AnyEvent->condvar;	418	my $result_ready = AnyEvent->condvar;
358		419
359	# do something such as adding a timer	420	# do something such as adding a timer
…		…
365	cb => sub { $result_ready->send },	426	cb => sub { $result_ready->send },
366	);	427	);
367		428
368	# this "blocks" (while handling events) till the callback	429	# this "blocks" (while handling events) till the callback
369	# calls send	430	# calls send
370	$result_ready->wait;	431	$result_ready->recv;
		432
		433	Example: wait for a timer, but take advantage of the fact that
		434	condition variables are also code references.
		435
		436	my $done = AnyEvent->condvar;
		437	my $delay = AnyEvent->timer (after => 5, cb => $done);
		438	$done->recv;
371		439
372	=head3 METHODS FOR PRODUCERS	440	=head3 METHODS FOR PRODUCERS
373		441
374	These methods should only be used by the producing side, i.e. the	442	These methods should only be used by the producing side, i.e. the
375	code/module that eventually sends the signal. Note that it is also	443	code/module that eventually sends the signal. Note that it is also
…		…
378		446
379	=over 4	447	=over 4
380		448
381	=item $cv->send (...)	449	=item $cv->send (...)
382		450
383	Flag the condition as ready - a running C<< ->wait >> and all further	451	Flag the condition as ready - a running C<< ->recv >> and all further
384	calls to C<wait> will (eventually) return after this method has been	452	calls to C<recv> will (eventually) return after this method has been
385	called. If nobody is waiting the send will be remembered.	453	called. If nobody is waiting the send will be remembered.
386		454
387	If a callback has been set on the condition variable, it is called	455	If a callback has been set on the condition variable, it is called
388	immediately from within send.	456	immediately from within send.
389		457
390	Any arguments passed to the C<send> call will be returned by all	458	Any arguments passed to the C<send> call will be returned by all
391	future C<< ->wait >> calls.	459	future C<< ->recv >> calls.
		460
		461	Condition variables are overloaded so one can call them directly
		462	(as a code reference). Calling them directly is the same as calling
		463	C<send>. Note, however, that many C-based event loops do not handle
		464	overloading, so as tempting as it may be, passing a condition variable
		465	instead of a callback does not work. Both the pure perl and EV loops
		466	support overloading, however, as well as all functions that use perl to
		467	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
		468	example).
392		469
393	=item $cv->croak ($error)	470	=item $cv->croak ($error)
394		471
395	Similar to send, but causes all call's wait C<< ->wait >> to invoke	472	Similar to send, but causes all call's to C<< ->recv >> to invoke
396	C<Carp::croak> with the given error message/object/scalar.	473	C<Carp::croak> with the given error message/object/scalar.
397		474
398	This can be used to signal any errors to the condition variable	475	This can be used to signal any errors to the condition variable
399	user/consumer.	476	user/consumer.
400		477
401	=item $cv->begin ([group callback])	478	=item $cv->begin ([group callback])
402		479
403	=item $cv->end	480	=item $cv->end
		481
		482	These two methods are EXPERIMENTAL and MIGHT CHANGE.
404		483
405	These two methods can be used to combine many transactions/events into	484	These two methods can be used to combine many transactions/events into
406	one. For example, a function that pings many hosts in parallel might want	485	one. For example, a function that pings many hosts in parallel might want
407	to use a condition variable for the whole process.	486	to use a condition variable for the whole process.
408		487
…		…
443	doesn't execute once).	522	doesn't execute once).
444		523
445	This is the general pattern when you "fan out" into multiple subrequests:	524	This is the general pattern when you "fan out" into multiple subrequests:
446	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	525	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>
447	is called at least once, and then, for each subrequest you start, call	526	is called at least once, and then, for each subrequest you start, call
448	C<begin> and for eahc subrequest you finish, call C<end>.	527	C<begin> and for each subrequest you finish, call C<end>.
449		528
450	=back	529	=back
451		530
452	=head3 METHODS FOR CONSUMERS	531	=head3 METHODS FOR CONSUMERS
453		532
454	These methods should only be used by the consuming side, i.e. the	533	These methods should only be used by the consuming side, i.e. the
455	code awaits the condition.	534	code awaits the condition.
456		535
457	=over 4	536	=over 4
458		537
459	=item $cv->wait	538	=item $cv->recv
460		539
461	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	540	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
462	>> methods have been called on c<$cv>, while servicing other watchers	541	>> methods have been called on c<$cv>, while servicing other watchers
463	normally.	542	normally.
464		543
…		…
475	(programs might want to do that to stay interactive), so I<if you are	554	(programs might want to do that to stay interactive), so I<if you are
476	using this from a module, never require a blocking wait>, but let the	555	using this from a module, never require a blocking wait>, but let the
477	caller decide whether the call will block or not (for example, by coupling	556	caller decide whether the call will block or not (for example, by coupling
478	condition variables with some kind of request results and supporting	557	condition variables with some kind of request results and supporting
479	callbacks so the caller knows that getting the result will not block,	558	callbacks so the caller knows that getting the result will not block,
480	while still suppporting blocking waits if the caller so desires).	559	while still supporting blocking waits if the caller so desires).
481		560
482	Another reason I<never> to C<< ->wait >> in a module is that you cannot	561	Another reason I<never> to C<< ->recv >> in a module is that you cannot
483	sensibly have two C<< ->wait >>'s in parallel, as that would require	562	sensibly have two C<< ->recv >>'s in parallel, as that would require
484	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	563	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
485	can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and	564	can supply.
486	L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
487	from different coroutines, however).
488		565
		566	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
		567	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
		568	versions and also integrates coroutines into AnyEvent, making blocking
		569	C<< ->recv >> calls perfectly safe as long as they are done from another
		570	coroutine (one that doesn't run the event loop).
		571
489	You can ensure that C<< -wait >> never blocks by setting a callback and	572	You can ensure that C<< -recv >> never blocks by setting a callback and
490	only calling C<< ->wait >> from within that callback (or at a later	573	only calling C<< ->recv >> from within that callback (or at a later
491	time). This will work even when the event loop does not support blocking	574	time). This will work even when the event loop does not support blocking
492	waits otherwise.	575	waits otherwise.
493		576
494	=item $bool = $cv->ready	577	=item $bool = $cv->ready
495		578
…		…
500		583
501	This is a mutator function that returns the callback set and optionally	584	This is a mutator function that returns the callback set and optionally
502	replaces it before doing so.	585	replaces it before doing so.
503		586
504	The callback will be called when the condition becomes "true", i.e. when	587	The callback will be called when the condition becomes "true", i.e. when
505	C<send> or C<croak> are called. Calling C<wait> inside the callback	588	C<send> or C<croak> are called. Calling C<recv> inside the callback
506	or at any later time is guaranteed not to block.	589	or at any later time is guaranteed not to block.
507		590
508	=back	591	=back
509		592
510	=head1 GLOBAL VARIABLES AND FUNCTIONS	593	=head1 GLOBAL VARIABLES AND FUNCTIONS
…		…
519	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	602	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
520	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	603	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
521		604
522	The known classes so far are:	605	The known classes so far are:
523		606
524	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
525	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
526	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).	607	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
527	AnyEvent::Impl::Event based on Event, second best choice.	608	AnyEvent::Impl::Event based on Event, second best choice.
528	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	609	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
529	AnyEvent::Impl::Glib based on Glib, third-best choice.	610	AnyEvent::Impl::Glib based on Glib, third-best choice.
530	AnyEvent::Impl::Tk based on Tk, very bad choice.	611	AnyEvent::Impl::Tk based on Tk, very bad choice.
…		…
547	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	628	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
548	if necessary. You should only call this function right before you would	629	if necessary. You should only call this function right before you would
549	have created an AnyEvent watcher anyway, that is, as late as possible at	630	have created an AnyEvent watcher anyway, that is, as late as possible at
550	runtime.	631	runtime.
551		632
		633	=item $guard = AnyEvent::post_detect { BLOCK }
		634
		635	Arranges for the code block to be executed as soon as the event model is
		636	autodetected (or immediately if this has already happened).
		637
		638	If called in scalar or list context, then it creates and returns an object
		639	that automatically removes the callback again when it is destroyed. See
		640	L<Coro::BDB> for a case where this is useful.
		641
		642	=item @AnyEvent::post_detect
		643
		644	If there are any code references in this array (you can C<push> to it
		645	before or after loading AnyEvent), then they will called directly after
		646	the event loop has been chosen.
		647
		648	You should check C<$AnyEvent::MODEL> before adding to this array, though:
		649	if it contains a true value then the event loop has already been detected,
		650	and the array will be ignored.
		651
		652	Best use C<AnyEvent::post_detect { BLOCK }> instead.
		653
552	=back	654	=back
553		655
554	=head1 WHAT TO DO IN A MODULE	656	=head1 WHAT TO DO IN A MODULE
555		657
556	As a module author, you should C<use AnyEvent> and call AnyEvent methods	658	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
559	Be careful when you create watchers in the module body - AnyEvent will	661	Be careful when you create watchers in the module body - AnyEvent will
560	decide which event module to use as soon as the first method is called, so	662	decide which event module to use as soon as the first method is called, so
561	by calling AnyEvent in your module body you force the user of your module	663	by calling AnyEvent in your module body you force the user of your module
562	to load the event module first.	664	to load the event module first.
563		665
564	Never call C<< ->wait >> on a condition variable unless you I<know> that	666	Never call C<< ->recv >> on a condition variable unless you I<know> that
565	the C<< ->send >> method has been called on it already. This is	667	the C<< ->send >> method has been called on it already. This is
566	because it will stall the whole program, and the whole point of using	668	because it will stall the whole program, and the whole point of using
567	events is to stay interactive.	669	events is to stay interactive.
568		670
569	It is fine, however, to call C<< ->wait >> when the user of your module	671	It is fine, however, to call C<< ->recv >> when the user of your module
570	requests it (i.e. if you create a http request object ad have a method	672	requests it (i.e. if you create a http request object ad have a method
571	called C<results> that returns the results, it should call C<< ->wait >>	673	called C<results> that returns the results, it should call C<< ->recv >>
572	freely, as the user of your module knows what she is doing. always).	674	freely, as the user of your module knows what she is doing. always).
573		675
574	=head1 WHAT TO DO IN THE MAIN PROGRAM	676	=head1 WHAT TO DO IN THE MAIN PROGRAM
575		677
576	There will always be a single main program - the only place that should	678	There will always be a single main program - the only place that should
…		…
578		680
579	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	681	If it doesn't care, it can just "use AnyEvent" and use it itself, or not
580	do anything special (it does not need to be event-based) and let AnyEvent	682	do anything special (it does not need to be event-based) and let AnyEvent
581	decide which implementation to chose if some module relies on it.	683	decide which implementation to chose if some module relies on it.
582		684
583	If the main program relies on a specific event model. For example, in	685	If the main program relies on a specific event model - for example, in
584	Gtk2 programs you have to rely on the Glib module. You should load the	686	Gtk2 programs you have to rely on the Glib module - you should load the
585	event module before loading AnyEvent or any module that uses it: generally	687	event module before loading AnyEvent or any module that uses it: generally
586	speaking, you should load it as early as possible. The reason is that	688	speaking, you should load it as early as possible. The reason is that
587	modules might create watchers when they are loaded, and AnyEvent will	689	modules might create watchers when they are loaded, and AnyEvent will
588	decide on the event model to use as soon as it creates watchers, and it	690	decide on the event model to use as soon as it creates watchers, and it
589	might chose the wrong one unless you load the correct one yourself.	691	might chose the wrong one unless you load the correct one yourself.
590		692
591	You can chose to use a rather inefficient pure-perl implementation by	693	You can chose to use a pure-perl implementation by loading the
592	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	694	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
593	behaviour everywhere, but letting AnyEvent chose is generally better.	695	everywhere, but letting AnyEvent chose the model is generally better.
		696
		697	=head2 MAINLOOP EMULATION
		698
		699	Sometimes (often for short test scripts, or even standalone programs who
		700	only want to use AnyEvent), you do not want to run a specific event loop.
		701
		702	In that case, you can use a condition variable like this:
		703
		704	AnyEvent->condvar->recv;
		705
		706	This has the effect of entering the event loop and looping forever.
		707
		708	Note that usually your program has some exit condition, in which case
		709	it is better to use the "traditional" approach of storing a condition
		710	variable somewhere, waiting for it, and sending it when the program should
		711	exit cleanly.
		712
594		713
595	=head1 OTHER MODULES	714	=head1 OTHER MODULES
596		715
597	The following is a non-exhaustive list of additional modules that use	716	The following is a non-exhaustive list of additional modules that use
598	AnyEvent and can therefore be mixed easily with other AnyEvent modules	717	AnyEvent and can therefore be mixed easily with other AnyEvent modules
…		…
610		729
611	Provide read and write buffers and manages watchers for reads and writes.	730	Provide read and write buffers and manages watchers for reads and writes.
612		731
613	=item L<AnyEvent::Socket>	732	=item L<AnyEvent::Socket>
614		733
615	Provides a means to do non-blocking connects, accepts etc.	734	Provides various utility functions for (internet protocol) sockets,
		735	addresses and name resolution. Also functions to create non-blocking tcp
		736	connections or tcp servers, with IPv6 and SRV record support and more.
		737
		738	=item L<AnyEvent::DNS>
		739
		740	Provides rich asynchronous DNS resolver capabilities.
616		741
617	=item L<AnyEvent::HTTPD>	742	=item L<AnyEvent::HTTPD>
618		743
619	Provides a simple web application server framework.	744	Provides a simple web application server framework.
620
621	=item L<AnyEvent::DNS>
622
623	Provides asynchronous DNS resolver capabilities, beyond what
624	L<AnyEvent::Util> offers.
625		745
626	=item L<AnyEvent::FastPing>	746	=item L<AnyEvent::FastPing>
627		747
628	The fastest ping in the west.	748	The fastest ping in the west.
629		749
…		…
644		764
645	High level API for event-based execution flow control.	765	High level API for event-based execution flow control.
646		766
647	=item L<Coro>	767	=item L<Coro>
648		768
649	Has special support for AnyEvent.	769	Has special support for AnyEvent via L<Coro::AnyEvent>.
		770
		771	=item L<AnyEvent::AIO>, L<IO::AIO>
		772
		773	Truly asynchronous I/O, should be in the toolbox of every event
		774	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
		775	together.
		776
		777	=item L<AnyEvent::BDB>, L<BDB>
		778
		779	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
		780	IO::AIO and AnyEvent together.
650		781
651	=item L<IO::Lambda>	782	=item L<IO::Lambda>
652		783
653	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	784	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
654
655	=item L<IO::AIO>
656
657	Truly asynchronous I/O, should be in the toolbox of every event
658	programmer. Can be trivially made to use AnyEvent.
659
660	=item L<BDB>
661
662	Truly asynchronous Berkeley DB access. Can be trivially made to use
663	AnyEvent.
664		785
665	=back	786	=back
666		787
667	=cut	788	=cut
668		789
…		…
671	no warnings;	792	no warnings;
672	use strict;	793	use strict;
673		794
674	use Carp;	795	use Carp;
675		796
676	our $VERSION = '3.3';	797	our $VERSION = '4.05';
677	our $MODEL;	798	our $MODEL;
678		799
679	our $AUTOLOAD;	800	our $AUTOLOAD;
680	our @ISA;	801	our @ISA;
681		802
		803	our @REGISTRY;
		804
		805	our $WIN32;
		806
		807	BEGIN {
		808	my $win32 = ! ! ($^O =~ /mswin32/i);
		809	eval "sub WIN32(){ $win32 }";
		810	}
		811
682	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	812	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
683		813
684	our @REGISTRY;	814	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
		815
		816	{
		817	my $idx;
		818	$PROTOCOL{$_} = ++$idx
		819	for reverse split /\s,\s/,
		820	$ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
		821	}
685		822
686	my @models = (	823	my @models = (
687	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
688	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
689	[EV:: => AnyEvent::Impl::EV::],	824	[EV:: => AnyEvent::Impl::EV::],
690	[Event:: => AnyEvent::Impl::Event::],	825	[Event:: => AnyEvent::Impl::Event::],
691	[Tk:: => AnyEvent::Impl::Tk::],
692	[Wx:: => AnyEvent::Impl::POE::],
693	[Prima:: => AnyEvent::Impl::POE::],
694	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	826	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
695	# everything below here will not be autoprobed as the pureperl backend should work everywhere	827	# everything below here will not be autoprobed
696	[Glib:: => AnyEvent::Impl::Glib::],	828	# as the pureperl backend should work everywhere
		829	# and is usually faster
		830	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		831	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
697	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	832	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
698	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	833	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
699	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	834	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
		835	[Wx:: => AnyEvent::Impl::POE::],
		836	[Prima:: => AnyEvent::Impl::POE::],
700	);	837	);
701		838
702	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);	839	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
		840
		841	our @post_detect;
		842
		843	sub post_detect(&) {
		844	my ($cb) = @_;
		845
		846	if ($MODEL) {
		847	$cb->();
		848
		849	1
		850	} else {
		851	push @post_detect, $cb;
		852
		853	defined wantarray
		854	? bless \$cb, "AnyEvent::Util::PostDetect"
		855	: ()
		856	}
		857	}
		858
		859	sub AnyEvent::Util::PostDetect::DESTROY {
		860	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		861	}
703		862
704	sub detect() {	863	sub detect() {
705	unless ($MODEL) {	864	unless ($MODEL) {
706	no strict 'refs';	865	no strict 'refs';
		866	local $SIG{__DIE__};
707		867
708	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	868	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
709	my $model = "AnyEvent::Impl::$1";	869	my $model = "AnyEvent::Impl::$1";
710	if (eval "require $model") {	870	if (eval "require $model") {
711	$MODEL = $model;	871	$MODEL = $model;
…		…
741	last;	901	last;
742	}	902	}
743	}	903	}
744		904
745	$MODEL	905	$MODEL
746	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib.";	906	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
747	}	907	}
748	}	908	}
749		909
750	unshift @ISA, $MODEL;	910	unshift @ISA, $MODEL;
751	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	911	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		912
		913	(shift @post_detect)->() while @post_detect;
752	}	914	}
753		915
754	$MODEL	916	$MODEL
755	}	917	}
756		918
…		…
766	$class->$func (@_);	928	$class->$func (@_);
767	}	929	}
768		930
769	package AnyEvent::Base;	931	package AnyEvent::Base;
770		932
		933	# default implementation for now and time
		934
		935	use Time::HiRes ();
		936
		937	sub time { Time::HiRes::time }
		938	sub now { Time::HiRes::time }
		939
771	# default implementation for ->condvar, ->wait, ->broadcast	940	# default implementation for ->condvar
772		941
773	sub condvar {	942	sub condvar {
774	bless \my $flag, "AnyEvent::Base::CondVar"	943	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
775	}
776
777	sub AnyEvent::Base::CondVar::broadcast {
778	${$_[0]}++;
779	}
780
781	sub AnyEvent::Base::CondVar::wait {
782	AnyEvent->one_event while !${$_[0]};
783	}	944	}
784		945
785	# default implementation for ->signal	946	# default implementation for ->signal
786		947
787	our %SIG_CB;	948	our %SIG_CB;
…		…
840	or Carp::croak "required option 'pid' is missing";	1001	or Carp::croak "required option 'pid' is missing";
841		1002
842	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1003	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
843		1004
844	unless ($WNOHANG) {	1005	unless ($WNOHANG) {
845	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } \|\| 1;	1006	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
846	}	1007	}
847		1008
848	unless ($CHLD_W) {	1009	unless ($CHLD_W) {
849	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1010	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
850	# child could be a zombie already, so make at least one round	1011	# child could be a zombie already, so make at least one round
…		…
860	delete $PID_CB{$pid}{$cb};	1021	delete $PID_CB{$pid}{$cb};
861	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1022	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
862		1023
863	undef $CHLD_W unless keys %PID_CB;	1024	undef $CHLD_W unless keys %PID_CB;
864	}	1025	}
		1026
		1027	package AnyEvent::CondVar;
		1028
		1029	our @ISA = AnyEvent::CondVar::Base::;
		1030
		1031	package AnyEvent::CondVar::Base;
		1032
		1033	use overload
		1034	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		1035	fallback => 1;
		1036
		1037	sub _send {
		1038	# nop
		1039	}
		1040
		1041	sub send {
		1042	my $cv = shift;
		1043	$cv->{_ae_sent} = [@_];
		1044	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		1045	$cv->_send;
		1046	}
		1047
		1048	sub croak {
		1049	$_[0]{_ae_croak} = $_[1];
		1050	$_[0]->send;
		1051	}
		1052
		1053	sub ready {
		1054	$_[0]{_ae_sent}
		1055	}
		1056
		1057	sub _wait {
		1058	AnyEvent->one_event while !$_[0]{_ae_sent};
		1059	}
		1060
		1061	sub recv {
		1062	$_[0]->_wait;
		1063
		1064	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		1065	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		1066	}
		1067
		1068	sub cb {
		1069	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		1070	$_[0]{_ae_cb}
		1071	}
		1072
		1073	sub begin {
		1074	++$_[0]{_ae_counter};
		1075	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		1076	}
		1077
		1078	sub end {
		1079	return if --$_[0]{_ae_counter};
		1080	&{ $_[0]{_ae_end_cb} \|\| sub { $_[0]->send } };
		1081	}
		1082
		1083	# undocumented/compatibility with pre-3.4
		1084	*broadcast = \&send;
		1085	*wait = \&_wait;
865		1086
866	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1087	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
867		1088
868	This is an advanced topic that you do not normally need to use AnyEvent in	1089	This is an advanced topic that you do not normally need to use AnyEvent in
869	a module. This section is only of use to event loop authors who want to	1090	a module. This section is only of use to event loop authors who want to
…		…
926	model it chooses.	1147	model it chooses.
927		1148
928	=item C<PERL_ANYEVENT_MODEL>	1149	=item C<PERL_ANYEVENT_MODEL>
929		1150
930	This can be used to specify the event model to be used by AnyEvent, before	1151	This can be used to specify the event model to be used by AnyEvent, before
931	autodetection and -probing kicks in. It must be a string consisting	1152	auto detection and -probing kicks in. It must be a string consisting
932	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1153	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
933	and the resulting module name is loaded and if the load was successful,	1154	and the resulting module name is loaded and if the load was successful,
934	used as event model. If it fails to load AnyEvent will proceed with	1155	used as event model. If it fails to load AnyEvent will proceed with
935	autodetection and -probing.	1156	auto detection and -probing.
936		1157
937	This functionality might change in future versions.	1158	This functionality might change in future versions.
938		1159
939	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1160	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
940	could start your program like this:	1161	could start your program like this:
941		1162
942	PERL_ANYEVENT_MODEL=Perl perl ...	1163	PERL_ANYEVENT_MODEL=Perl perl ...
		1164
		1165	=item C<PERL_ANYEVENT_PROTOCOLS>
		1166
		1167	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1168	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1169	of auto probing).
		1170
		1171	Must be set to a comma-separated list of protocols or address families,
		1172	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1173	used, and preference will be given to protocols mentioned earlier in the
		1174	list.
		1175
		1176	This variable can effectively be used for denial-of-service attacks
		1177	against local programs (e.g. when setuid), although the impact is likely
		1178	small, as the program has to handle connection errors already-
		1179
		1180	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1181	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1182	- only support IPv4, never try to resolve or contact IPv6
		1183	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1184	IPv6, but prefer IPv6 over IPv4.
		1185
		1186	=item C<PERL_ANYEVENT_EDNS0>
		1187
		1188	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1189	for DNS. This extension is generally useful to reduce DNS traffic, but
		1190	some (broken) firewalls drop such DNS packets, which is why it is off by
		1191	default.
		1192
		1193	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1194	EDNS0 in its DNS requests.
		1195
		1196	=item C<PERL_ANYEVENT_MAX_FORKS>
		1197
		1198	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1199	will create in parallel.
943		1200
944	=back	1201	=back
945		1202
946	=head1 EXAMPLE PROGRAM	1203	=head1 EXAMPLE PROGRAM
947		1204
…		…
958	poll => 'r',	1215	poll => 'r',
959	cb => sub {	1216	cb => sub {
960	warn "io event <$_[0]>\n"; # will always output <r>	1217	warn "io event <$_[0]>\n"; # will always output <r>
961	chomp (my $input = <STDIN>); # read a line	1218	chomp (my $input = <STDIN>); # read a line
962	warn "read: $input\n"; # output what has been read	1219	warn "read: $input\n"; # output what has been read
963	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1220	$cv->send if $input =~ /^q/i; # quit program if /^q/i
964	},	1221	},
965	);	1222	);
966		1223
967	my $time_watcher; # can only be used once	1224	my $time_watcher; # can only be used once
968		1225
…		…
973	});	1230	});
974	}	1231	}
975		1232
976	new_timer; # create first timer	1233	new_timer; # create first timer
977		1234
978	$cv->wait; # wait until user enters /^q/i	1235	$cv->recv; # wait until user enters /^q/i
979		1236
980	=head1 REAL-WORLD EXAMPLE	1237	=head1 REAL-WORLD EXAMPLE
981		1238
982	Consider the L<Net::FCP> module. It features (among others) the following	1239	Consider the L<Net::FCP> module. It features (among others) the following
983	API calls, which are to freenet what HTTP GET requests are to http:	1240	API calls, which are to freenet what HTTP GET requests are to http:
…		…
1033	syswrite $txn->{fh}, $txn->{request}	1290	syswrite $txn->{fh}, $txn->{request}
1034	or die "connection or write error";	1291	or die "connection or write error";
1035	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1292	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1036		1293
1037	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1294	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
1038	result and signals any possible waiters that the request ahs finished:	1295	result and signals any possible waiters that the request has finished:
1039		1296
1040	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1297	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1041		1298
1042	if (end-of-file or data complete) {	1299	if (end-of-file or data complete) {
1043	$txn->{result} = $txn->{buf};	1300	$txn->{result} = $txn->{buf};
1044	$txn->{finished}->broadcast;	1301	$txn->{finished}->send;
1045	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1302	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
1046	}	1303	}
1047		1304
1048	The C<result> method, finally, just waits for the finished signal (if the	1305	The C<result> method, finally, just waits for the finished signal (if the
1049	request was already finished, it doesn't wait, of course, and returns the	1306	request was already finished, it doesn't wait, of course, and returns the
1050	data:	1307	data:
1051		1308
1052	$txn->{finished}->wait;	1309	$txn->{finished}->recv;
1053	return $txn->{result};	1310	return $txn->{result};
1054		1311
1055	The actual code goes further and collects all errors (C<die>s, exceptions)	1312	The actual code goes further and collects all errors (C<die>s, exceptions)
1056	that occured during request processing. The C<result> method detects	1313	that occurred during request processing. The C<result> method detects
1057	whether an exception as thrown (it is stored inside the $txn object)	1314	whether an exception as thrown (it is stored inside the $txn object)
1058	and just throws the exception, which means connection errors and other	1315	and just throws the exception, which means connection errors and other
1059	problems get reported tot he code that tries to use the result, not in a	1316	problems get reported tot he code that tries to use the result, not in a
1060	random callback.	1317	random callback.
1061		1318
…		…
1092		1349
1093	my $quit = AnyEvent->condvar;	1350	my $quit = AnyEvent->condvar;
1094		1351
1095	$fcp->txn_client_get ($url)->cb (sub {	1352	$fcp->txn_client_get ($url)->cb (sub {
1096	...	1353	...
1097	$quit->broadcast;	1354	$quit->send;
1098	});	1355	});
1099		1356
1100	$quit->wait;	1357	$quit->recv;
1101		1358
1102		1359
1103	=head1 BENCHMARKS	1360	=head1 BENCHMARKS
1104		1361
1105	To give you an idea of the performance and overheads that AnyEvent adds	1362	To give you an idea of the performance and overheads that AnyEvent adds
…		…
1107	of various event loops I prepared some benchmarks.	1364	of various event loops I prepared some benchmarks.
1108		1365
1109	=head2 BENCHMARKING ANYEVENT OVERHEAD	1366	=head2 BENCHMARKING ANYEVENT OVERHEAD
1110		1367
1111	Here is a benchmark of various supported event models used natively and	1368	Here is a benchmark of various supported event models used natively and
1112	through anyevent. The benchmark creates a lot of timers (with a zero	1369	through AnyEvent. The benchmark creates a lot of timers (with a zero
1113	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	1370	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1114	which it is), lets them fire exactly once and destroys them again.	1371	which it is), lets them fire exactly once and destroys them again.
1115		1372
1116	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1373	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1117	distribution.	1374	distribution.
…		…
1134	all watchers, to avoid adding memory overhead. That means closure creation	1391	all watchers, to avoid adding memory overhead. That means closure creation
1135	and memory usage is not included in the figures.	1392	and memory usage is not included in the figures.
1136		1393
1137	I<invoke> is the time, in microseconds, used to invoke a simple	1394	I<invoke> is the time, in microseconds, used to invoke a simple
1138	callback. The callback simply counts down a Perl variable and after it was	1395	callback. The callback simply counts down a Perl variable and after it was
1139	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1396	invoked "watcher" times, it would C<< ->send >> a condvar once to
1140	signal the end of this phase.	1397	signal the end of this phase.
1141		1398
1142	I<destroy> is the time, in microseconds, that it takes to destroy a single	1399	I<destroy> is the time, in microseconds, that it takes to destroy a single
1143	watcher.	1400	watcher.
1144		1401
…		…
1240		1497
1241	=back	1498	=back
1242		1499
1243	=head2 BENCHMARKING THE LARGE SERVER CASE	1500	=head2 BENCHMARKING THE LARGE SERVER CASE
1244		1501
1245	This benchmark atcually benchmarks the event loop itself. It works by	1502	This benchmark actually benchmarks the event loop itself. It works by
1246	creating a number of "servers": each server consists of a socketpair, a	1503	creating a number of "servers": each server consists of a socket pair, a
1247	timeout watcher that gets reset on activity (but never fires), and an I/O	1504	timeout watcher that gets reset on activity (but never fires), and an I/O
1248	watcher waiting for input on one side of the socket. Each time the socket	1505	watcher waiting for input on one side of the socket. Each time the socket
1249	watcher reads a byte it will write that byte to a random other "server".	1506	watcher reads a byte it will write that byte to a random other "server".
1250		1507
1251	The effect is that there will be a lot of I/O watchers, only part of which	1508	The effect is that there will be a lot of I/O watchers, only part of which
1252	are active at any one point (so there is a constant number of active	1509	are active at any one point (so there is a constant number of active
1253	fds for each loop iterstaion, but which fds these are is random). The	1510	fds for each loop iteration, but which fds these are is random). The
1254	timeout is reset each time something is read because that reflects how	1511	timeout is reset each time something is read because that reflects how
1255	most timeouts work (and puts extra pressure on the event loops).	1512	most timeouts work (and puts extra pressure on the event loops).
1256		1513
1257	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1514	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1258	(1%) are active. This mirrors the activity of large servers with many	1515	(1%) are active. This mirrors the activity of large servers with many
1259	connections, most of which are idle at any one point in time.	1516	connections, most of which are idle at any one point in time.
1260		1517
1261	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1518	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1262	distribution.	1519	distribution.
…		…
1264	=head3 Explanation of the columns	1521	=head3 Explanation of the columns
1265		1522
1266	I<sockets> is the number of sockets, and twice the number of "servers" (as	1523	I<sockets> is the number of sockets, and twice the number of "servers" (as
1267	each server has a read and write socket end).	1524	each server has a read and write socket end).
1268		1525
1269	I<create> is the time it takes to create a socketpair (which is	1526	I<create> is the time it takes to create a socket pair (which is
1270	nontrivial) and two watchers: an I/O watcher and a timeout watcher.	1527	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1271		1528
1272	I<request>, the most important value, is the time it takes to handle a	1529	I<request>, the most important value, is the time it takes to handle a
1273	single "request", that is, reading the token from the pipe and forwarding	1530	single "request", that is, reading the token from the pipe and forwarding
1274	it to another server. This includes deleting the old timeout and creating	1531	it to another server. This includes deleting the old timeout and creating
…		…
1347	speed most when you have lots of watchers, not when you only have a few of	1604	speed most when you have lots of watchers, not when you only have a few of
1348	them).	1605	them).
1349		1606
1350	EV is again fastest.	1607	EV is again fastest.
1351		1608
1352	Perl again comes second. It is noticably faster than the C-based event	1609	Perl again comes second. It is noticeably faster than the C-based event
1353	loops Event and Glib, although the difference is too small to really	1610	loops Event and Glib, although the difference is too small to really
1354	matter.	1611	matter.
1355		1612
1356	POE also performs much better in this case, but is is still far behind the	1613	POE also performs much better in this case, but is is still far behind the
1357	others.	1614	others.
…		…
1397	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	1654	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
1398		1655
1399		1656
1400	=head1 SEE ALSO	1657	=head1 SEE ALSO
1401		1658
1402	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,	1659	Utility functions: L<AnyEvent::Util>.
1403	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,	1660
		1661	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1404	L<Event::Lib>, L<Qt>, L<POE>.	1662	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1405		1663
1406	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,	1664	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1407	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,	1665	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1408	L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>,	1666	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1409	L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>.	1667	L<AnyEvent::Impl::POE>.
1410		1668
		1669	Non-blocking file handles, sockets, TCP clients and
		1670	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1671
		1672	Asynchronous DNS: L<AnyEvent::DNS>.
		1673
		1674	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
		1675
1411	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1676	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1412		1677
1413		1678
1414	=head1 AUTHOR	1679	=head1 AUTHOR
1415		1680
1416	Marc Lehmann <schmorp@schmorp.de>	1681	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.107 by root, Tue May 6 12:15:50 2008 UTC vs.
Revision 1.143 by root, Wed May 28 23:57:38 2008 UTC