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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.100 by elmex, Sun Apr 27 19:15:43 2008 UTC vs.
Revision 1.128 by root, Sat May 24 02:50:45 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 ->broadcast	21	$w->recv; # enters "main loop" till $condvar gets ->send
21	$w->broadcast; # 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?
…		…
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, if you want lots of policy (this can arguably be somewhat	67	Of course, if you 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	68	useful) and you want to force your users to use the one and only event
69	model, you should I<not> use this module.	69	model, you should I<not> use this module.
70
71	#TODO#
72
73	Net::IRC3
74	AnyEvent::HTTPD
75	AnyEvent::DNS
76	IO::AnyEvent
77	Net::FPing
78	Net::XMPP2
79	Coro
80
81	AnyEvent::IRC
82	AnyEvent::HTTPD
83	AnyEvent::DNS
84	AnyEvent::Handle
85	AnyEvent::Socket
86	AnyEvent::FPing
87	AnyEvent::XMPP
88	AnyEvent::SNMP
89	Coro
90		70
91	=head1 DESCRIPTION	71	=head1 DESCRIPTION
92		72
93	L<AnyEvent> provides an identical interface to multiple event loops. This	73	L<AnyEvent> provides an identical interface to multiple event loops. This
94	allows module authors to utilise an event loop without forcing module	74	allows module authors to utilise an event loop without forcing module
…		…
98	The interface itself is vaguely similar, but not identical to the L<Event>	78	The interface itself is vaguely similar, but not identical to the L<Event>
99	module.	79	module.
100		80
101	During the first call of any watcher-creation method, the module tries	81	During the first call of any watcher-creation method, the module tries
102	to detect the currently loaded event loop by probing whether one of the	82	to detect the currently loaded event loop by probing whether one of the
103	following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>,	83	following modules is already loaded: L<EV>,
104	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	84	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,
105	L<POE>. The first one found is used. If none are found, the module tries	85	L<POE>. The first one found is used. If none are found, the module tries
106	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	86	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl
107	adaptor should always succeed) in the order given. The first one that can	87	adaptor should always succeed) in the order given. The first one that can
108	be successfully loaded will be used. If, after this, still none could be	88	be successfully loaded will be used. If, after this, still none could be
…		…
128		108
129	=head1 WATCHERS	109	=head1 WATCHERS
130		110
131	AnyEvent has the central concept of a I<watcher>, which is an object that	111	AnyEvent has the central concept of a I<watcher>, which is an object that
132	stores relevant data for each kind of event you are waiting for, such as	112	stores relevant data for each kind of event you are waiting for, such as
133	the callback to call, the filehandle to watch, etc.	113	the callback to call, the file handle to watch, etc.
134		114
135	These watchers are normal Perl objects with normal Perl lifetime. After	115	These watchers are normal Perl objects with normal Perl lifetime. After
136	creating a watcher it will immediately "watch" for events and invoke the	116	creating a watcher it will immediately "watch" for events and invoke the
137	callback when the event occurs (of course, only when the event model	117	callback when the event occurs (of course, only when the event model
138	is in control).	118	is in control).
…		…
299		279
300	Example: fork a process and wait for it	280	Example: fork a process and wait for it
301		281
302	my $done = AnyEvent->condvar;	282	my $done = AnyEvent->condvar;
303		283
304	AnyEvent::detect; # force event module to be initialised
305
306	my $pid = fork or exit 5;	284	my $pid = fork or exit 5;
307		285
308	my $w = AnyEvent->child (	286	my $w = AnyEvent->child (
309	pid => $pid,	287	pid => $pid,
310	cb => sub {	288	cb => sub {
311	my ($pid, $status) = @_;	289	my ($pid, $status) = @_;
312	warn "pid $pid exited with status $status";	290	warn "pid $pid exited with status $status";
313	$done->broadcast;	291	$done->send;
314	},	292	},
315	);	293	);
316		294
317	# do something else, then wait for process exit	295	# do something else, then wait for process exit
318	$done->wait;	296	$done->recv;
319		297
320	=head2 CONDITION VARIABLES	298	=head2 CONDITION VARIABLES
321		299
		300	If you are familiar with some event loops you will know that all of them
		301	require you to run some blocking "loop", "run" or similar function that
		302	will actively watch for new events and call your callbacks.
		303
		304	AnyEvent is different, it expects somebody else to run the event loop and
		305	will only block when necessary (usually when told by the user).
		306
		307	The instrument to do that is called a "condition variable", so called
		308	because they represent a condition that must become true.
		309
322	Condition variables can be created by calling the C<< AnyEvent->condvar >>	310	Condition variables can be created by calling the C<< AnyEvent->condvar
323	method without any arguments.	311	>> method, usually without arguments. The only argument pair allowed is
		312	C<cb>, which specifies a callback to be called when the condition variable
		313	becomes true.
324		314
325	A condition variable waits for a condition - precisely that the C<<	315	After creation, the conditon variable is "false" until it becomes "true"
326	->broadcast >> method has been called.	316	by calling the C<send> method.
327		317
328	They are very useful to signal that a condition has been fulfilled, for	318	Condition variables are similar to callbacks, except that you can
		319	optionally wait for them. They can also be called merge points - points
		320	in time where multiple outstandign events have been processed. And yet
		321	another way to call them is transations - each condition variable can be
		322	used to represent a transaction, which finishes at some point and delivers
		323	a result.
		324
		325	Condition variables are very useful to signal that something has finished,
329	example, if you write a module that does asynchronous http requests,	326	for example, if you write a module that does asynchronous http requests,
330	then a condition variable would be the ideal candidate to signal the	327	then a condition variable would be the ideal candidate to signal the
331	availability of results.	328	availability of results. The user can either act when the callback is
		329	called or can synchronously C<< ->recv >> for the results.
332		330
333	You can also use condition variables to block your main program until	331	You can also use them to simulate traditional event loops - for example,
334	an event occurs - for example, you could C<< ->wait >> in your main	332	you can block your main program until an event occurs - for example, you
335	program until the user clicks the Quit button in your app, which would C<<	333	could C<< ->recv >> in your main program until the user clicks the Quit
336	->broadcast >> the "quit" event.	334	button of your app, which would C<< ->send >> the "quit" event.
337		335
338	Note that condition variables recurse into the event loop - if you have	336	Note that condition variables recurse into the event loop - if you have
339	two pirces of code that call C<< ->wait >> in a round-robbin fashion, you	337	two pieces of code that call C<< ->recv >> in a round-robbin fashion, you
340	lose. Therefore, condition variables are good to export to your caller, but	338	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,	339	you should avoid making a blocking wait yourself, at least in callbacks,
342	as this asks for trouble.	340	as this asks for trouble.
343		341
344	This object has two methods:	342	Condition variables are represented by hash refs in perl, and the keys
		343	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
		344	easy (it is often useful to build your own transaction class on top of
		345	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
		346	it's C<new> method in your own C<new> method.
		347
		348	There are two "sides" to a condition variable - the "producer side" which
		349	eventually calls C<< -> send >>, and the "consumer side", which waits
		350	for the send to occur.
		351
		352	Example:
		353
		354	# wait till the result is ready
		355	my $result_ready = AnyEvent->condvar;
		356
		357	# do something such as adding a timer
		358	# or socket watcher the calls $result_ready->send
		359	# when the "result" is ready.
		360	# in this case, we simply use a timer:
		361	my $w = AnyEvent->timer (
		362	after => 1,
		363	cb => sub { $result_ready->send },
		364	);
		365
		366	# this "blocks" (while handling events) till the callback
		367	# calls send
		368	$result_ready->recv;
		369
		370	=head3 METHODS FOR PRODUCERS
		371
		372	These methods should only be used by the producing side, i.e. the
		373	code/module that eventually sends the signal. Note that it is also
		374	the producer side which creates the condvar in most cases, but it isn't
		375	uncommon for the consumer to create it as well.
345		376
346	=over 4	377	=over 4
347		378
		379	=item $cv->send (...)
		380
		381	Flag the condition as ready - a running C<< ->recv >> and all further
		382	calls to C<recv> will (eventually) return after this method has been
		383	called. If nobody is waiting the send will be remembered.
		384
		385	If a callback has been set on the condition variable, it is called
		386	immediately from within send.
		387
		388	Any arguments passed to the C<send> call will be returned by all
		389	future C<< ->recv >> calls.
		390
		391	=item $cv->croak ($error)
		392
		393	Similar to send, but causes all call's to C<< ->recv >> to invoke
		394	C<Carp::croak> with the given error message/object/scalar.
		395
		396	This can be used to signal any errors to the condition variable
		397	user/consumer.
		398
		399	=item $cv->begin ([group callback])
		400
348	=item $cv->wait	401	=item $cv->end
349		402
350	Wait (blocking if necessary) until the C<< ->broadcast >> method has been	403	These two methods are EXPERIMENTAL and MIGHT CHANGE.
		404
		405	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
		407	to use a condition variable for the whole process.
		408
		409	Every call to C<< ->begin >> will increment a counter, and every call to
		410	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
		411	>>, the (last) callback passed to C<begin> will be executed. That callback
		412	is I<supposed> to call C<< ->send >>, but that is not required. If no
		413	callback was set, C<send> will be called without any arguments.
		414
		415	Let's clarify this with the ping example:
		416
		417	my $cv = AnyEvent->condvar;
		418
		419	my %result;
		420	$cv->begin (sub { $cv->send (\%result) });
		421
		422	for my $host (@list_of_hosts) {
		423	$cv->begin;
		424	ping_host_then_call_callback $host, sub {
		425	$result{$host} = ...;
		426	$cv->end;
		427	};
		428	}
		429
		430	$cv->end;
		431
		432	This code fragment supposedly pings a number of hosts and calls
		433	C<send> after results for all then have have been gathered - in any
		434	order. To achieve this, the code issues a call to C<begin> when it starts
		435	each ping request and calls C<end> when it has received some result for
		436	it. Since C<begin> and C<end> only maintain a counter, the order in which
		437	results arrive is not relevant.
		438
		439	There is an additional bracketing call to C<begin> and C<end> outside the
		440	loop, which serves two important purposes: first, it sets the callback
		441	to be called once the counter reaches C<0>, and second, it ensures that
		442	C<send> is called even when C<no> hosts are being pinged (the loop
		443	doesn't execute once).
		444
		445	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>
		447	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>.
		449
		450	=back
		451
		452	=head3 METHODS FOR CONSUMERS
		453
		454	These methods should only be used by the consuming side, i.e. the
		455	code awaits the condition.
		456
		457	=over 4
		458
		459	=item $cv->recv
		460
		461	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
351	called on c<$cv>, while servicing other watchers normally.	462	>> methods have been called on c<$cv>, while servicing other watchers
		463	normally.
352		464
353	You can only wait once on a condition - additional calls will return	465	You can only wait once on a condition - additional calls are valid but
354	immediately.	466	will return immediately.
		467
		468	If an error condition has been set by calling C<< ->croak >>, then this
		469	function will call C<croak>.
		470
		471	In list context, all parameters passed to C<send> will be returned,
		472	in scalar context only the first one will be returned.
355		473
356	Not all event models support a blocking wait - some die in that case	474	Not all event models support a blocking wait - some die in that case
357	(programs might want to do that to stay interactive), so I<if you are	475	(programs might want to do that to stay interactive), so I<if you are
358	using this from a module, never require a blocking wait>, but let the	476	using this from a module, never require a blocking wait>, but let the
359	caller decide whether the call will block or not (for example, by coupling	477	caller decide whether the call will block or not (for example, by coupling
360	condition variables with some kind of request results and supporting	478	condition variables with some kind of request results and supporting
361	callbacks so the caller knows that getting the result will not block,	479	callbacks so the caller knows that getting the result will not block,
362	while still suppporting blocking waits if the caller so desires).	480	while still suppporting blocking waits if the caller so desires).
363		481
364	Another reason I<never> to C<< ->wait >> in a module is that you cannot	482	Another reason I<never> to C<< ->recv >> in a module is that you cannot
365	sensibly have two C<< ->wait >>'s in parallel, as that would require	483	sensibly have two C<< ->recv >>'s in parallel, as that would require
366	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	484	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
367	can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and	485	can supply.
368	L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
369	from different coroutines, however).
370		486
371	=item $cv->broadcast	487	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
		488	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
		489	versions and also integrates coroutines into AnyEvent, making blocking
		490	C<< ->recv >> calls perfectly safe as long as they are done from another
		491	coroutine (one that doesn't run the event loop).
372		492
373	Flag the condition as ready - a running C<< ->wait >> and all further	493	You can ensure that C<< -recv >> never blocks by setting a callback and
374	calls to C<wait> will (eventually) return after this method has been	494	only calling C<< ->recv >> from within that callback (or at a later
375	called. If nobody is waiting the broadcast will be remembered..	495	time). This will work even when the event loop does not support blocking
		496	waits otherwise.
		497
		498	=item $bool = $cv->ready
		499
		500	Returns true when the condition is "true", i.e. whether C<send> or
		501	C<croak> have been called.
		502
		503	=item $cb = $cv->cb ([new callback])
		504
		505	This is a mutator function that returns the callback set and optionally
		506	replaces it before doing so.
		507
		508	The callback will be called when the condition becomes "true", i.e. when
		509	C<send> or C<croak> are called. Calling C<recv> inside the callback
		510	or at any later time is guaranteed not to block.
376		511
377	=back	512	=back
378
379	Example:
380
381	# wait till the result is ready
382	my $result_ready = AnyEvent->condvar;
383
384	# do something such as adding a timer
385	# or socket watcher the calls $result_ready->broadcast
386	# when the "result" is ready.
387	# in this case, we simply use a timer:
388	my $w = AnyEvent->timer (
389	after => 1,
390	cb => sub { $result_ready->broadcast },
391	);
392
393	# this "blocks" (while handling events) till the watcher
394	# calls broadcast
395	$result_ready->wait;
396		513
397	=head1 GLOBAL VARIABLES AND FUNCTIONS	514	=head1 GLOBAL VARIABLES AND FUNCTIONS
398		515
399	=over 4	516	=over 4
400		517
…		…
406	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	523	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
407	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	524	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
408		525
409	The known classes so far are:	526	The known classes so far are:
410		527
411	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
412	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
413	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).	528	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
414	AnyEvent::Impl::Event based on Event, second best choice.	529	AnyEvent::Impl::Event based on Event, second best choice.
		530	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
415	AnyEvent::Impl::Glib based on Glib, third-best choice.	531	AnyEvent::Impl::Glib based on Glib, third-best choice.
416	AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable.
417	AnyEvent::Impl::Tk based on Tk, very bad choice.	532	AnyEvent::Impl::Tk based on Tk, very bad choice.
418	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).	533	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
419	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	534	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
420	AnyEvent::Impl::POE based on POE, not generic enough for full support.	535	AnyEvent::Impl::POE based on POE, not generic enough for full support.
421		536
…		…
434	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	549	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
435	if necessary. You should only call this function right before you would	550	if necessary. You should only call this function right before you would
436	have created an AnyEvent watcher anyway, that is, as late as possible at	551	have created an AnyEvent watcher anyway, that is, as late as possible at
437	runtime.	552	runtime.
438		553
		554	=item $guard = AnyEvent::post_detect { BLOCK }
		555
		556	Arranges for the code block to be executed as soon as the event model is
		557	autodetected (or immediately if this has already happened).
		558
		559	If called in scalar or list context, then it creates and returns an object
		560	that automatically removes the callback again when it is destroyed. See
		561	L<Coro::BDB> for a case where this is useful.
		562
		563	=item @AnyEvent::post_detect
		564
		565	If there are any code references in this array (you can C<push> to it
		566	before or after loading AnyEvent), then they will called directly after
		567	the event loop has been chosen.
		568
		569	You should check C<$AnyEvent::MODEL> before adding to this array, though:
		570	if it contains a true value then the event loop has already been detected,
		571	and the array will be ignored.
		572
		573	Best use C<AnyEvent::post_detect { BLOCK }> instead.
		574
439	=back	575	=back
440		576
441	=head1 WHAT TO DO IN A MODULE	577	=head1 WHAT TO DO IN A MODULE
442		578
443	As a module author, you should C<use AnyEvent> and call AnyEvent methods	579	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
446	Be careful when you create watchers in the module body - AnyEvent will	582	Be careful when you create watchers in the module body - AnyEvent will
447	decide which event module to use as soon as the first method is called, so	583	decide which event module to use as soon as the first method is called, so
448	by calling AnyEvent in your module body you force the user of your module	584	by calling AnyEvent in your module body you force the user of your module
449	to load the event module first.	585	to load the event module first.
450		586
451	Never call C<< ->wait >> on a condition variable unless you I<know> that	587	Never call C<< ->recv >> on a condition variable unless you I<know> that
452	the C<< ->broadcast >> method has been called on it already. This is	588	the C<< ->send >> method has been called on it already. This is
453	because it will stall the whole program, and the whole point of using	589	because it will stall the whole program, and the whole point of using
454	events is to stay interactive.	590	events is to stay interactive.
455		591
456	It is fine, however, to call C<< ->wait >> when the user of your module	592	It is fine, however, to call C<< ->recv >> when the user of your module
457	requests it (i.e. if you create a http request object ad have a method	593	requests it (i.e. if you create a http request object ad have a method
458	called C<results> that returns the results, it should call C<< ->wait >>	594	called C<results> that returns the results, it should call C<< ->recv >>
459	freely, as the user of your module knows what she is doing. always).	595	freely, as the user of your module knows what she is doing. always).
460		596
461	=head1 WHAT TO DO IN THE MAIN PROGRAM	597	=head1 WHAT TO DO IN THE MAIN PROGRAM
462		598
463	There will always be a single main program - the only place that should	599	There will always be a single main program - the only place that should
…		…
479	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	615	loading the C<AnyEvent::Impl::Perl> module, which gives you similar
480	behaviour everywhere, but letting AnyEvent chose is generally better.	616	behaviour everywhere, but letting AnyEvent chose is generally better.
481		617
482	=head1 OTHER MODULES	618	=head1 OTHER MODULES
483		619
484	L<AnyEvent> itself comes with useful utility modules:	620	The following is a non-exhaustive list of additional modules that use
485		621	AnyEvent and can therefore be mixed easily with other AnyEvent modules
486	To make it easier to do non-blocking IO the modules L<AnyEvent::Handle>	622	in the same program. Some of the modules come with AnyEvent, some are
487	and L<AnyEvent::Socket> are provided. L<AnyEvent::Handle> provides	623	available via CPAN.
488	read and write buffers and manages watchers for reads and writes.
489	L<AnyEvent::Socket> provides means to do non-blocking connects.
490
491	Aside from those there are these modules that support AnyEvent (and use it
492	for non-blocking IO):
493		624
494	=over 4	625	=over 4
495		626
		627	=item L<AnyEvent::Util>
		628
		629	Contains various utility functions that replace often-used but blocking
		630	functions such as C<inet_aton> by event-/callback-based versions.
		631
		632	=item L<AnyEvent::Handle>
		633
		634	Provide read and write buffers and manages watchers for reads and writes.
		635
		636	=item L<AnyEvent::Socket>
		637
		638	Provides various utility functions for (internet protocol) sockets,
		639	addresses and name resolution. Also functions to create non-blocking tcp
		640	connections or tcp servers, with IPv6 and SRV record support and more.
		641
		642	=item L<AnyEvent::HTTPD>
		643
		644	Provides a simple web application server framework.
		645
		646	=item L<AnyEvent::DNS>
		647
		648	Provides rich asynchronous DNS resolver capabilities.
		649
496	=item L<AnyEvent::FastPing>	650	=item L<AnyEvent::FastPing>
497		651
		652	The fastest ping in the west.
		653
498	=item L<Net::IRC3>	654	=item L<Net::IRC3>
499		655
		656	AnyEvent based IRC client module family.
		657
500	=item L<Net::XMPP2>	658	=item L<Net::XMPP2>
		659
		660	AnyEvent based XMPP (Jabber protocol) module family.
		661
		662	=item L<Net::FCP>
		663
		664	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
		665	of AnyEvent.
		666
		667	=item L<Event::ExecFlow>
		668
		669	High level API for event-based execution flow control.
		670
		671	=item L<Coro>
		672
		673	Has special support for AnyEvent via L<Coro::AnyEvent>.
		674
		675	=item L<AnyEvent::AIO>, L<IO::AIO>
		676
		677	Truly asynchronous I/O, should be in the toolbox of every event
		678	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
		679	together.
		680
		681	=item L<AnyEvent::BDB>, L<BDB>
		682
		683	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
		684	IO::AIO and AnyEvent together.
		685
		686	=item L<IO::Lambda>
		687
		688	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
501		689
502	=back	690	=back
503		691
504	=cut	692	=cut
505		693
…		…
508	no warnings;	696	no warnings;
509	use strict;	697	use strict;
510		698
511	use Carp;	699	use Carp;
512		700
513	our $VERSION = '3.3';	701	our $VERSION = '3.6';
514	our $MODEL;	702	our $MODEL;
515		703
516	our $AUTOLOAD;	704	our $AUTOLOAD;
517	our @ISA;	705	our @ISA;
518		706
519	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	707	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
520		708
521	our @REGISTRY;	709	our @REGISTRY;
522		710
		711	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2)
		712
		713	{
		714	my $idx;
		715	$PROTOCOL{$_} = ++$idx
		716	for split /\s,\s/, $ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
		717	}
		718
523	my @models = (	719	my @models = (
524	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
525	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
526	[EV:: => AnyEvent::Impl::EV::],	720	[EV:: => AnyEvent::Impl::EV::],
527	[Event:: => AnyEvent::Impl::Event::],	721	[Event:: => AnyEvent::Impl::Event::],
528	[Glib:: => AnyEvent::Impl::Glib::],
529	[Tk:: => AnyEvent::Impl::Tk::],	722	[Tk:: => AnyEvent::Impl::Tk::],
530	[Wx:: => AnyEvent::Impl::POE::],	723	[Wx:: => AnyEvent::Impl::POE::],
531	[Prima:: => AnyEvent::Impl::POE::],	724	[Prima:: => AnyEvent::Impl::POE::],
532	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	725	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
533	# everything below here will not be autoprobed as the pureperl backend should work everywhere	726	# everything below here will not be autoprobed as the pureperl backend should work everywhere
		727	[Glib:: => AnyEvent::Impl::Glib::],
534	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	728	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
535	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	729	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
536	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	730	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
537	);	731	);
538		732
539	our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY);	733	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);
		734
		735	our @post_detect;
		736
		737	sub post_detect(&) {
		738	my ($cb) = @_;
		739
		740	if ($MODEL) {
		741	$cb->();
		742
		743	1
		744	} else {
		745	push @post_detect, $cb;
		746
		747	defined wantarray
		748	? bless \$cb, "AnyEvent::Util::PostDetect"
		749	: ()
		750	}
		751	}
		752
		753	sub AnyEvent::Util::PostDetect::DESTROY {
		754	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		755	}
540		756
541	sub detect() {	757	sub detect() {
542	unless ($MODEL) {	758	unless ($MODEL) {
543	no strict 'refs';	759	no strict 'refs';
544		760
…		…
578	last;	794	last;
579	}	795	}
580	}	796	}
581		797
582	$MODEL	798	$MODEL
583	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.";	799	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
584	}	800	}
585	}	801	}
586		802
587	unshift @ISA, $MODEL;	803	unshift @ISA, $MODEL;
588	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	804	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		805
		806	(shift @post_detect)->() while @post_detect;
589	}	807	}
590		808
591	$MODEL	809	$MODEL
592	}	810	}
593		811
…		…
603	$class->$func (@_);	821	$class->$func (@_);
604	}	822	}
605		823
606	package AnyEvent::Base;	824	package AnyEvent::Base;
607		825
608	# default implementation for ->condvar, ->wait, ->broadcast	826	# default implementation for ->condvar
609		827
610	sub condvar {	828	sub condvar {
611	bless \my $flag, "AnyEvent::Base::CondVar"	829	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
612	}
613
614	sub AnyEvent::Base::CondVar::broadcast {
615	${$_[0]}++;
616	}
617
618	sub AnyEvent::Base::CondVar::wait {
619	AnyEvent->one_event while !${$_[0]};
620	}	830	}
621		831
622	# default implementation for ->signal	832	# default implementation for ->signal
623		833
624	our %SIG_CB;	834	our %SIG_CB;
…		…
698	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	908	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
699		909
700	undef $CHLD_W unless keys %PID_CB;	910	undef $CHLD_W unless keys %PID_CB;
701	}	911	}
702		912
		913	package AnyEvent::CondVar;
		914
		915	our @ISA = AnyEvent::CondVar::Base::;
		916
		917	package AnyEvent::CondVar::Base;
		918
		919	sub _send {
		920	# nop
		921	}
		922
		923	sub send {
		924	my $cv = shift;
		925	$cv->{_ae_sent} = [@_];
		926	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		927	$cv->_send;
		928	}
		929
		930	sub croak {
		931	$_[0]{_ae_croak} = $_[1];
		932	$_[0]->send;
		933	}
		934
		935	sub ready {
		936	$_[0]{_ae_sent}
		937	}
		938
		939	sub _wait {
		940	AnyEvent->one_event while !$_[0]{_ae_sent};
		941	}
		942
		943	sub recv {
		944	$_[0]->_wait;
		945
		946	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		947	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		948	}
		949
		950	sub cb {
		951	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		952	$_[0]{_ae_cb}
		953	}
		954
		955	sub begin {
		956	++$_[0]{_ae_counter};
		957	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		958	}
		959
		960	sub end {
		961	return if --$_[0]{_ae_counter};
		962	&{ $_[0]{_ae_end_cb} \|\| sub { $_[0]->send } };
		963	}
		964
		965	# undocumented/compatibility with pre-3.4
		966	*broadcast = \&send;
		967	*wait = \&_wait;
		968
703	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	969	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
704		970
705	This is an advanced topic that you do not normally need to use AnyEvent in	971	This is an advanced topic that you do not normally need to use AnyEvent in
706	a module. This section is only of use to event loop authors who want to	972	a module. This section is only of use to event loop authors who want to
707	provide AnyEvent compatibility.	973	provide AnyEvent compatibility.
…		…
763	model it chooses.	1029	model it chooses.
764		1030
765	=item C<PERL_ANYEVENT_MODEL>	1031	=item C<PERL_ANYEVENT_MODEL>
766		1032
767	This can be used to specify the event model to be used by AnyEvent, before	1033	This can be used to specify the event model to be used by AnyEvent, before
768	autodetection and -probing kicks in. It must be a string consisting	1034	auto detection and -probing kicks in. It must be a string consisting
769	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1035	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
770	and the resulting module name is loaded and if the load was successful,	1036	and the resulting module name is loaded and if the load was successful,
771	used as event model. If it fails to load AnyEvent will proceed with	1037	used as event model. If it fails to load AnyEvent will proceed with
772	autodetection and -probing.	1038	auto detection and -probing.
773		1039
774	This functionality might change in future versions.	1040	This functionality might change in future versions.
775		1041
776	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1042	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
777	could start your program like this:	1043	could start your program like this:
778		1044
779	PERL_ANYEVENT_MODEL=Perl perl ...	1045	PERL_ANYEVENT_MODEL=Perl perl ...
		1046
		1047	=item C<PERL_ANYEVENT_PROTOCOLS>
		1048
		1049	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1050	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1051	of auto probing).
		1052
		1053	Must be set to a comma-separated list of protocols or address families,
		1054	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1055	used, and preference will be given to protocols mentioned earlier in the
		1056	list.
		1057
		1058	This variable can effectively be used for denial-of-service attacks
		1059	against local programs (e.g. when setuid), although the impact is likely
		1060	small, as the program has to handle connection errors already-
		1061
		1062	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1063	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1064	- only support IPv4, never try to resolve or contact IPv6
		1065	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1066	IPv6, but prefer IPv6 over IPv4.
		1067
		1068	=item C<PERL_ANYEVENT_EDNS0>
		1069
		1070	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1071	for DNS. This extension is generally useful to reduce DNS traffic, but
		1072	some (broken) firewalls drop such DNS packets, which is why it is off by
		1073	default.
		1074
		1075	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1076	EDNS0 in its DNS requests.
780		1077
781	=back	1078	=back
782		1079
783	=head1 EXAMPLE PROGRAM	1080	=head1 EXAMPLE PROGRAM
784		1081
…		…
795	poll => 'r',	1092	poll => 'r',
796	cb => sub {	1093	cb => sub {
797	warn "io event <$_[0]>\n"; # will always output <r>	1094	warn "io event <$_[0]>\n"; # will always output <r>
798	chomp (my $input = <STDIN>); # read a line	1095	chomp (my $input = <STDIN>); # read a line
799	warn "read: $input\n"; # output what has been read	1096	warn "read: $input\n"; # output what has been read
800	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1097	$cv->send if $input =~ /^q/i; # quit program if /^q/i
801	},	1098	},
802	);	1099	);
803		1100
804	my $time_watcher; # can only be used once	1101	my $time_watcher; # can only be used once
805		1102
…		…
810	});	1107	});
811	}	1108	}
812		1109
813	new_timer; # create first timer	1110	new_timer; # create first timer
814		1111
815	$cv->wait; # wait until user enters /^q/i	1112	$cv->recv; # wait until user enters /^q/i
816		1113
817	=head1 REAL-WORLD EXAMPLE	1114	=head1 REAL-WORLD EXAMPLE
818		1115
819	Consider the L<Net::FCP> module. It features (among others) the following	1116	Consider the L<Net::FCP> module. It features (among others) the following
820	API calls, which are to freenet what HTTP GET requests are to http:	1117	API calls, which are to freenet what HTTP GET requests are to http:
…		…
870	syswrite $txn->{fh}, $txn->{request}	1167	syswrite $txn->{fh}, $txn->{request}
871	or die "connection or write error";	1168	or die "connection or write error";
872	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1169	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
873		1170
874	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1171	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
875	result and signals any possible waiters that the request ahs finished:	1172	result and signals any possible waiters that the request has finished:
876		1173
877	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1174	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
878		1175
879	if (end-of-file or data complete) {	1176	if (end-of-file or data complete) {
880	$txn->{result} = $txn->{buf};	1177	$txn->{result} = $txn->{buf};
881	$txn->{finished}->broadcast;	1178	$txn->{finished}->send;
882	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1179	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
883	}	1180	}
884		1181
885	The C<result> method, finally, just waits for the finished signal (if the	1182	The C<result> method, finally, just waits for the finished signal (if the
886	request was already finished, it doesn't wait, of course, and returns the	1183	request was already finished, it doesn't wait, of course, and returns the
887	data:	1184	data:
888		1185
889	$txn->{finished}->wait;	1186	$txn->{finished}->recv;
890	return $txn->{result};	1187	return $txn->{result};
891		1188
892	The actual code goes further and collects all errors (C<die>s, exceptions)	1189	The actual code goes further and collects all errors (C<die>s, exceptions)
893	that occured during request processing. The C<result> method detects	1190	that occurred during request processing. The C<result> method detects
894	whether an exception as thrown (it is stored inside the $txn object)	1191	whether an exception as thrown (it is stored inside the $txn object)
895	and just throws the exception, which means connection errors and other	1192	and just throws the exception, which means connection errors and other
896	problems get reported tot he code that tries to use the result, not in a	1193	problems get reported tot he code that tries to use the result, not in a
897	random callback.	1194	random callback.
898		1195
…		…
929		1226
930	my $quit = AnyEvent->condvar;	1227	my $quit = AnyEvent->condvar;
931		1228
932	$fcp->txn_client_get ($url)->cb (sub {	1229	$fcp->txn_client_get ($url)->cb (sub {
933	...	1230	...
934	$quit->broadcast;	1231	$quit->send;
935	});	1232	});
936		1233
937	$quit->wait;	1234	$quit->recv;
938		1235
939		1236
940	=head1 BENCHMARKS	1237	=head1 BENCHMARKS
941		1238
942	To give you an idea of the performance and overheads that AnyEvent adds	1239	To give you an idea of the performance and overheads that AnyEvent adds
…		…
944	of various event loops I prepared some benchmarks.	1241	of various event loops I prepared some benchmarks.
945		1242
946	=head2 BENCHMARKING ANYEVENT OVERHEAD	1243	=head2 BENCHMARKING ANYEVENT OVERHEAD
947		1244
948	Here is a benchmark of various supported event models used natively and	1245	Here is a benchmark of various supported event models used natively and
949	through anyevent. The benchmark creates a lot of timers (with a zero	1246	through AnyEvent. The benchmark creates a lot of timers (with a zero
950	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	1247	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
951	which it is), lets them fire exactly once and destroys them again.	1248	which it is), lets them fire exactly once and destroys them again.
952		1249
953	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1250	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
954	distribution.	1251	distribution.
…		…
971	all watchers, to avoid adding memory overhead. That means closure creation	1268	all watchers, to avoid adding memory overhead. That means closure creation
972	and memory usage is not included in the figures.	1269	and memory usage is not included in the figures.
973		1270
974	I<invoke> is the time, in microseconds, used to invoke a simple	1271	I<invoke> is the time, in microseconds, used to invoke a simple
975	callback. The callback simply counts down a Perl variable and after it was	1272	callback. The callback simply counts down a Perl variable and after it was
976	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1273	invoked "watcher" times, it would C<< ->send >> a condvar once to
977	signal the end of this phase.	1274	signal the end of this phase.
978		1275
979	I<destroy> is the time, in microseconds, that it takes to destroy a single	1276	I<destroy> is the time, in microseconds, that it takes to destroy a single
980	watcher.	1277	watcher.
981		1278
…		…
1041	file descriptor is dup()ed for each watcher. This shows that the dup()	1338	file descriptor is dup()ed for each watcher. This shows that the dup()
1042	employed by some adaptors is not a big performance issue (it does incur a	1339	employed by some adaptors is not a big performance issue (it does incur a
1043	hidden memory cost inside the kernel which is not reflected in the figures	1340	hidden memory cost inside the kernel which is not reflected in the figures
1044	above).	1341	above).
1045		1342
1046	C<POE>, regardless of underlying event loop (whether using its pure	1343	C<POE>, regardless of underlying event loop (whether using its pure perl
1047	perl select-based backend or the Event module, the POE-EV backend	1344	select-based backend or the Event module, the POE-EV backend couldn't
1048	couldn't be tested because it wasn't working) shows abysmal performance	1345	be tested because it wasn't working) shows abysmal performance and
1049	and memory usage: Watchers use almost 30 times as much memory as	1346	memory usage with AnyEvent: Watchers use almost 30 times as much memory
1050	EV watchers, and 10 times as much memory as Event (the high memory	1347	as EV watchers, and 10 times as much memory as Event (the high memory
1051	requirements are caused by requiring a session for each watcher). Watcher	1348	requirements are caused by requiring a session for each watcher). Watcher
1052	invocation speed is almost 900 times slower than with AnyEvent's pure perl	1349	invocation speed is almost 900 times slower than with AnyEvent's pure perl
		1350	implementation.
		1351
1053	implementation. The design of the POE adaptor class in AnyEvent can not	1352	The design of the POE adaptor class in AnyEvent can not really account
1054	really account for this, as session creation overhead is small compared	1353	for the performance issues, though, as session creation overhead is
1055	to execution of the state machine, which is coded pretty optimally within	1354	small compared to execution of the state machine, which is coded pretty
1056	L<AnyEvent::Impl::POE>. POE simply seems to be abysmally slow.	1355	optimally within L<AnyEvent::Impl::POE> (and while everybody agrees that
		1356	using multiple sessions is not a good approach, especially regarding
		1357	memory usage, even the author of POE could not come up with a faster
		1358	design).
1057		1359
1058	=head3 Summary	1360	=head3 Summary
1059		1361
1060	=over 4	1362	=over 4
1061		1363
…		…
1072		1374
1073	=back	1375	=back
1074		1376
1075	=head2 BENCHMARKING THE LARGE SERVER CASE	1377	=head2 BENCHMARKING THE LARGE SERVER CASE
1076		1378
1077	This benchmark atcually benchmarks the event loop itself. It works by	1379	This benchmark actually benchmarks the event loop itself. It works by
1078	creating a number of "servers": each server consists of a socketpair, a	1380	creating a number of "servers": each server consists of a socket pair, a
1079	timeout watcher that gets reset on activity (but never fires), and an I/O	1381	timeout watcher that gets reset on activity (but never fires), and an I/O
1080	watcher waiting for input on one side of the socket. Each time the socket	1382	watcher waiting for input on one side of the socket. Each time the socket
1081	watcher reads a byte it will write that byte to a random other "server".	1383	watcher reads a byte it will write that byte to a random other "server".
1082		1384
1083	The effect is that there will be a lot of I/O watchers, only part of which	1385	The effect is that there will be a lot of I/O watchers, only part of which
1084	are active at any one point (so there is a constant number of active	1386	are active at any one point (so there is a constant number of active
1085	fds for each loop iterstaion, but which fds these are is random). The	1387	fds for each loop iteration, but which fds these are is random). The
1086	timeout is reset each time something is read because that reflects how	1388	timeout is reset each time something is read because that reflects how
1087	most timeouts work (and puts extra pressure on the event loops).	1389	most timeouts work (and puts extra pressure on the event loops).
1088		1390
1089	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1391	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1090	(1%) are active. This mirrors the activity of large servers with many	1392	(1%) are active. This mirrors the activity of large servers with many
1091	connections, most of which are idle at any one point in time.	1393	connections, most of which are idle at any one point in time.
1092		1394
1093	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1395	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1094	distribution.	1396	distribution.
…		…
1096	=head3 Explanation of the columns	1398	=head3 Explanation of the columns
1097		1399
1098	I<sockets> is the number of sockets, and twice the number of "servers" (as	1400	I<sockets> is the number of sockets, and twice the number of "servers" (as
1099	each server has a read and write socket end).	1401	each server has a read and write socket end).
1100		1402
1101	I<create> is the time it takes to create a socketpair (which is	1403	I<create> is the time it takes to create a socket pair (which is
1102	nontrivial) and two watchers: an I/O watcher and a timeout watcher.	1404	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1103		1405
1104	I<request>, the most important value, is the time it takes to handle a	1406	I<request>, the most important value, is the time it takes to handle a
1105	single "request", that is, reading the token from the pipe and forwarding	1407	single "request", that is, reading the token from the pipe and forwarding
1106	it to another server. This includes deleting the old timeout and creating	1408	it to another server. This includes deleting the old timeout and creating
…		…
1140		1442
1141	=head3 Summary	1443	=head3 Summary
1142		1444
1143	=over 4	1445	=over 4
1144		1446
1145	=item * The pure perl implementation performs extremely well, considering	1447	=item * The pure perl implementation performs extremely well.
1146	that it uses select.
1147		1448
1148	=item * Avoid Glib or POE in large projects where performance matters.	1449	=item * Avoid Glib or POE in large projects where performance matters.
1149		1450
1150	=back	1451	=back
1151		1452
…		…
1180	speed most when you have lots of watchers, not when you only have a few of	1481	speed most when you have lots of watchers, not when you only have a few of
1181	them).	1482	them).
1182		1483
1183	EV is again fastest.	1484	EV is again fastest.
1184		1485
1185	The C-based event loops Event and Glib come in second this time, as the	1486	Perl again comes second. It is noticably faster than the C-based event
1186	overhead of running an iteration is much smaller in C than in Perl (little	1487	loops Event and Glib, although the difference is too small to really
1187	code to execute in the inner loop, and perl's function calling overhead is	1488	matter.
1188	high, and updating all the data structures is costly).
1189
1190	The pure perl event loop is much slower, but still competitive.
1191		1489
1192	POE also performs much better in this case, but is is still far behind the	1490	POE also performs much better in this case, but is is still far behind the
1193	others.	1491	others.
1194		1492
1195	=head3 Summary	1493	=head3 Summary
…		…
1203		1501
1204		1502
1205	=head1 FORK	1503	=head1 FORK
1206		1504
1207	Most event libraries are not fork-safe. The ones who are usually are	1505	Most event libraries are not fork-safe. The ones who are usually are
1208	because they are so inefficient. Only L<EV> is fully fork-aware.	1506	because they rely on inefficient but fork-safe C<select> or C<poll>
		1507	calls. Only L<EV> is fully fork-aware.
1209		1508
1210	If you have to fork, you must either do so I<before> creating your first	1509	If you have to fork, you must either do so I<before> creating your first
1211	watcher OR you must not use AnyEvent at all in the child.	1510	watcher OR you must not use AnyEvent at all in the child.
1212		1511
1213		1512
…		…
1225		1524
1226	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1525	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1227		1526
1228	use AnyEvent;	1527	use AnyEvent;
1229		1528
		1529	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
		1530	be used to probe what backend is used and gain other information (which is
		1531	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
		1532
1230		1533
1231	=head1 SEE ALSO	1534	=head1 SEE ALSO
1232		1535
1233	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,	1536	Utility functions: L<AnyEvent::Util>.
1234	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,	1537
		1538	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1235	L<Event::Lib>, L<Qt>, L<POE>.	1539	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1236		1540
1237	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,	1541	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1238	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,	1542	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1239	L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>,	1543	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1240	L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>.	1544	L<AnyEvent::Impl::POE>.
1241		1545
		1546	Non-blocking file handles, sockets, TCP clients and
		1547	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1548
		1549	Asynchronous DNS: L<AnyEvent::DNS>.
		1550
		1551	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
		1552
1242	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1553	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1243		1554
1244		1555
1245	=head1 AUTHOR	1556	=head1 AUTHOR
1246		1557
1247	Marc Lehmann <schmorp@schmorp.de>	1558	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.100 by elmex, Sun Apr 27 19:15:43 2008 UTC vs. Revision 1.128 by root, Sat May 24 02:50:45 2008 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.100 by elmex, Sun Apr 27 19:15:43 2008 UTC vs.
Revision 1.128 by root, Sat May 24 02:50:45 2008 UTC