[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 1.133 by root, Sun May 25 03:44:03 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).
…		…
257		237
258	Although the callback might get passed parameters, their value and	238	Although the callback might get passed parameters, their value and
259	presence is undefined and you cannot rely on them. Portable AnyEvent	239	presence is undefined and you cannot rely on them. Portable AnyEvent
260	callbacks cannot use arguments passed to signal watcher callbacks.	240	callbacks cannot use arguments passed to signal watcher callbacks.
261		241
262	Multiple signal occurances can be clumped together into one callback	242	Multiple signal occurrences can be clumped together into one callback
263	invocation, and callback invocation will be synchronous. synchronous means	243	invocation, and callback invocation will be synchronous. Synchronous means
264	that it might take a while until the signal gets handled by the process,	244	that it might take a while until the signal gets handled by the process,
265	but it is guarenteed not to interrupt any other callbacks.	245	but it is guaranteed not to interrupt any other callbacks.
266		246
267	The main advantage of using these watchers is that you can share a signal	247	The main advantage of using these watchers is that you can share a signal
268	between multiple watchers.	248	between multiple watchers.
269		249
270	This watcher might use C<%SIG>, so programs overwriting those signals	250	This watcher might use C<%SIG>, so programs overwriting those signals
…		…
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 condition variable is "false" until it becomes "true"
326	->broadcast >> method has been called.	316	by calling the C<send> method (or calling the condition variable as if it
		317	were a callback).
327		318
328	They are very useful to signal that a condition has been fulfilled, for	319	Condition variables are similar to callbacks, except that you can
		320	optionally wait for them. They can also be called merge points - points
		321	in time where multiple outstanding events have been processed. And yet
		322	another way to call them is transactions - each condition variable can be
		323	used to represent a transaction, which finishes at some point and delivers
		324	a result.
		325
		326	Condition variables are very useful to signal that something has finished,
329	example, if you write a module that does asynchronous http requests,	327	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	328	then a condition variable would be the ideal candidate to signal the
331	availability of results.	329	availability of results. The user can either act when the callback is
		330	called or can synchronously C<< ->recv >> for the results.
332		331
333	You can also use condition variables to block your main program until	332	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	333	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<<	334	could C<< ->recv >> in your main program until the user clicks the Quit
336	->broadcast >> the "quit" event.	335	button of your app, which would C<< ->send >> the "quit" event.
337		336
338	Note that condition variables recurse into the event loop - if you have	337	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	338	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	339	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,	340	you should avoid making a blocking wait yourself, at least in callbacks,
342	as this asks for trouble.	341	as this asks for trouble.
343		342
344	This object has two methods:	343	Condition variables are represented by hash refs in perl, and the keys
		344	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
		345	easy (it is often useful to build your own transaction class on top of
		346	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
		347	it's C<new> method in your own C<new> method.
		348
		349	There are two "sides" to a condition variable - the "producer side" which
		350	eventually calls C<< -> send >>, and the "consumer side", which waits
		351	for the send to occur.
		352
		353	Example: wait for a timer.
		354
		355	# wait till the result is ready
		356	my $result_ready = AnyEvent->condvar;
		357
		358	# do something such as adding a timer
		359	# or socket watcher the calls $result_ready->send
		360	# when the "result" is ready.
		361	# in this case, we simply use a timer:
		362	my $w = AnyEvent->timer (
		363	after => 1,
		364	cb => sub { $result_ready->send },
		365	);
		366
		367	# this "blocks" (while handling events) till the callback
		368	# calls send
		369	$result_ready->recv;
		370
		371	Example: wait for a timer, but take advantage of the fact that
		372	condition variables are also code references.
		373
		374	my $done = AnyEvent->condvar;
		375	my $delay = AnyEvent->timer (after => 5, cb => $done);
		376	$done->recv;
		377
		378	=head3 METHODS FOR PRODUCERS
		379
		380	These methods should only be used by the producing side, i.e. the
		381	code/module that eventually sends the signal. Note that it is also
		382	the producer side which creates the condvar in most cases, but it isn't
		383	uncommon for the consumer to create it as well.
345		384
346	=over 4	385	=over 4
347		386
		387	=item $cv->send (...)
		388
		389	Flag the condition as ready - a running C<< ->recv >> and all further
		390	calls to C<recv> will (eventually) return after this method has been
		391	called. If nobody is waiting the send will be remembered.
		392
		393	If a callback has been set on the condition variable, it is called
		394	immediately from within send.
		395
		396	Any arguments passed to the C<send> call will be returned by all
		397	future C<< ->recv >> calls.
		398
		399	Condition variables are overloaded so one can call them directly (as a
		400	code reference). Calling them directly is the same as calling C<send>.
		401
		402	=item $cv->croak ($error)
		403
		404	Similar to send, but causes all call's to C<< ->recv >> to invoke
		405	C<Carp::croak> with the given error message/object/scalar.
		406
		407	This can be used to signal any errors to the condition variable
		408	user/consumer.
		409
		410	=item $cv->begin ([group callback])
		411
348	=item $cv->wait	412	=item $cv->end
349		413
350	Wait (blocking if necessary) until the C<< ->broadcast >> method has been	414	These two methods are EXPERIMENTAL and MIGHT CHANGE.
		415
		416	These two methods can be used to combine many transactions/events into
		417	one. For example, a function that pings many hosts in parallel might want
		418	to use a condition variable for the whole process.
		419
		420	Every call to C<< ->begin >> will increment a counter, and every call to
		421	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
		422	>>, the (last) callback passed to C<begin> will be executed. That callback
		423	is I<supposed> to call C<< ->send >>, but that is not required. If no
		424	callback was set, C<send> will be called without any arguments.
		425
		426	Let's clarify this with the ping example:
		427
		428	my $cv = AnyEvent->condvar;
		429
		430	my %result;
		431	$cv->begin (sub { $cv->send (\%result) });
		432
		433	for my $host (@list_of_hosts) {
		434	$cv->begin;
		435	ping_host_then_call_callback $host, sub {
		436	$result{$host} = ...;
		437	$cv->end;
		438	};
		439	}
		440
		441	$cv->end;
		442
		443	This code fragment supposedly pings a number of hosts and calls
		444	C<send> after results for all then have have been gathered - in any
		445	order. To achieve this, the code issues a call to C<begin> when it starts
		446	each ping request and calls C<end> when it has received some result for
		447	it. Since C<begin> and C<end> only maintain a counter, the order in which
		448	results arrive is not relevant.
		449
		450	There is an additional bracketing call to C<begin> and C<end> outside the
		451	loop, which serves two important purposes: first, it sets the callback
		452	to be called once the counter reaches C<0>, and second, it ensures that
		453	C<send> is called even when C<no> hosts are being pinged (the loop
		454	doesn't execute once).
		455
		456	This is the general pattern when you "fan out" into multiple subrequests:
		457	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>
		458	is called at least once, and then, for each subrequest you start, call
		459	C<begin> and for each subrequest you finish, call C<end>.
		460
		461	=back
		462
		463	=head3 METHODS FOR CONSUMERS
		464
		465	These methods should only be used by the consuming side, i.e. the
		466	code awaits the condition.
		467
		468	=over 4
		469
		470	=item $cv->recv
		471
		472	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
351	called on c<$cv>, while servicing other watchers normally.	473	>> methods have been called on c<$cv>, while servicing other watchers
		474	normally.
352		475
353	You can only wait once on a condition - additional calls will return	476	You can only wait once on a condition - additional calls are valid but
354	immediately.	477	will return immediately.
		478
		479	If an error condition has been set by calling C<< ->croak >>, then this
		480	function will call C<croak>.
		481
		482	In list context, all parameters passed to C<send> will be returned,
		483	in scalar context only the first one will be returned.
355		484
356	Not all event models support a blocking wait - some die in that case	485	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	486	(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	487	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	488	caller decide whether the call will block or not (for example, by coupling
360	condition variables with some kind of request results and supporting	489	condition variables with some kind of request results and supporting
361	callbacks so the caller knows that getting the result will not block,	490	callbacks so the caller knows that getting the result will not block,
362	while still suppporting blocking waits if the caller so desires).	491	while still supporting blocking waits if the caller so desires).
363		492
364	Another reason I<never> to C<< ->wait >> in a module is that you cannot	493	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	494	sensibly have two C<< ->recv >>'s in parallel, as that would require
366	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	495	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
367	can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and	496	can supply.
368	L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
369	from different coroutines, however).
370		497
371	=item $cv->broadcast	498	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
		499	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
		500	versions and also integrates coroutines into AnyEvent, making blocking
		501	C<< ->recv >> calls perfectly safe as long as they are done from another
		502	coroutine (one that doesn't run the event loop).
372		503
373	Flag the condition as ready - a running C<< ->wait >> and all further	504	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	505	only calling C<< ->recv >> from within that callback (or at a later
375	called. If nobody is waiting the broadcast will be remembered..	506	time). This will work even when the event loop does not support blocking
		507	waits otherwise.
		508
		509	=item $bool = $cv->ready
		510
		511	Returns true when the condition is "true", i.e. whether C<send> or
		512	C<croak> have been called.
		513
		514	=item $cb = $cv->cb ([new callback])
		515
		516	This is a mutator function that returns the callback set and optionally
		517	replaces it before doing so.
		518
		519	The callback will be called when the condition becomes "true", i.e. when
		520	C<send> or C<croak> are called. Calling C<recv> inside the callback
		521	or at any later time is guaranteed not to block.
376		522
377	=back	523	=back
378		524
379	Example:	525	=head3 MAINLOOP EMULATION
380		526
381	# wait till the result is ready	527	Sometimes (often for short test scripts, or even standalone programs
382	my $result_ready = AnyEvent->condvar;	528	who only want to use AnyEvent), you I<do> want your program to block
		529	indefinitely in some event loop.
383		530
384	# do something such as adding a timer	531	In that case, you cna use a condition variable like this:
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		532
393	# this "blocks" (while handling events) till the watcher	533	AnyEvent->condvar->recv;
394	# calls broadcast	534
395	$result_ready->wait;	535	This has the effect of entering the event loop and looping forever.
		536
		537	Note that usually your program has some exit condition, in which case
		538	it is better to use the "traditional" approach of storing a condition
		539	variable, waiting for it, and sending it when the program should exit
		540	cleanly.
		541
396		542
397	=head1 GLOBAL VARIABLES AND FUNCTIONS	543	=head1 GLOBAL VARIABLES AND FUNCTIONS
398		544
399	=over 4	545	=over 4
400		546
…		…
406	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	552	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>).	553	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
408		554
409	The known classes so far are:	555	The known classes so far are:
410		556
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).	557	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
414	AnyEvent::Impl::Event based on Event, second best choice.	558	AnyEvent::Impl::Event based on Event, second best choice.
		559	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
415	AnyEvent::Impl::Glib based on Glib, third-best choice.	560	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.	561	AnyEvent::Impl::Tk based on Tk, very bad choice.
418	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).	562	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
419	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	563	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
420	AnyEvent::Impl::POE based on POE, not generic enough for full support.	564	AnyEvent::Impl::POE based on POE, not generic enough for full support.
421		565
…		…
434	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	578	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
435	if necessary. You should only call this function right before you would	579	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	580	have created an AnyEvent watcher anyway, that is, as late as possible at
437	runtime.	581	runtime.
438		582
		583	=item $guard = AnyEvent::post_detect { BLOCK }
		584
		585	Arranges for the code block to be executed as soon as the event model is
		586	autodetected (or immediately if this has already happened).
		587
		588	If called in scalar or list context, then it creates and returns an object
		589	that automatically removes the callback again when it is destroyed. See
		590	L<Coro::BDB> for a case where this is useful.
		591
		592	=item @AnyEvent::post_detect
		593
		594	If there are any code references in this array (you can C<push> to it
		595	before or after loading AnyEvent), then they will called directly after
		596	the event loop has been chosen.
		597
		598	You should check C<$AnyEvent::MODEL> before adding to this array, though:
		599	if it contains a true value then the event loop has already been detected,
		600	and the array will be ignored.
		601
		602	Best use C<AnyEvent::post_detect { BLOCK }> instead.
		603
439	=back	604	=back
440		605
441	=head1 WHAT TO DO IN A MODULE	606	=head1 WHAT TO DO IN A MODULE
442		607
443	As a module author, you should C<use AnyEvent> and call AnyEvent methods	608	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	611	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	612	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	613	by calling AnyEvent in your module body you force the user of your module
449	to load the event module first.	614	to load the event module first.
450		615
451	Never call C<< ->wait >> on a condition variable unless you I<know> that	616	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	617	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	618	because it will stall the whole program, and the whole point of using
454	events is to stay interactive.	619	events is to stay interactive.
455		620
456	It is fine, however, to call C<< ->wait >> when the user of your module	621	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	622	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 >>	623	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).	624	freely, as the user of your module knows what she is doing. always).
460		625
461	=head1 WHAT TO DO IN THE MAIN PROGRAM	626	=head1 WHAT TO DO IN THE MAIN PROGRAM
462		627
463	There will always be a single main program - the only place that should	628	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	644	loading the C<AnyEvent::Impl::Perl> module, which gives you similar
480	behaviour everywhere, but letting AnyEvent chose is generally better.	645	behaviour everywhere, but letting AnyEvent chose is generally better.
481		646
482	=head1 OTHER MODULES	647	=head1 OTHER MODULES
483		648
484	L<AnyEvent> itself comes with useful utility modules:	649	The following is a non-exhaustive list of additional modules that use
485		650	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>	651	in the same program. Some of the modules come with AnyEvent, some are
487	and L<AnyEvent::Socket> are provided. L<AnyEvent::Handle> provides	652	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		653
494	=over 4	654	=over 4
495		655
		656	=item L<AnyEvent::Util>
		657
		658	Contains various utility functions that replace often-used but blocking
		659	functions such as C<inet_aton> by event-/callback-based versions.
		660
		661	=item L<AnyEvent::Handle>
		662
		663	Provide read and write buffers and manages watchers for reads and writes.
		664
		665	=item L<AnyEvent::Socket>
		666
		667	Provides various utility functions for (internet protocol) sockets,
		668	addresses and name resolution. Also functions to create non-blocking tcp
		669	connections or tcp servers, with IPv6 and SRV record support and more.
		670
		671	=item L<AnyEvent::HTTPD>
		672
		673	Provides a simple web application server framework.
		674
		675	=item L<AnyEvent::DNS>
		676
		677	Provides rich asynchronous DNS resolver capabilities.
		678
496	=item L<AnyEvent::FastPing>	679	=item L<AnyEvent::FastPing>
497		680
		681	The fastest ping in the west.
		682
498	=item L<Net::IRC3>	683	=item L<Net::IRC3>
499		684
		685	AnyEvent based IRC client module family.
		686
500	=item L<Net::XMPP2>	687	=item L<Net::XMPP2>
		688
		689	AnyEvent based XMPP (Jabber protocol) module family.
		690
		691	=item L<Net::FCP>
		692
		693	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
		694	of AnyEvent.
		695
		696	=item L<Event::ExecFlow>
		697
		698	High level API for event-based execution flow control.
		699
		700	=item L<Coro>
		701
		702	Has special support for AnyEvent via L<Coro::AnyEvent>.
		703
		704	=item L<AnyEvent::AIO>, L<IO::AIO>
		705
		706	Truly asynchronous I/O, should be in the toolbox of every event
		707	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
		708	together.
		709
		710	=item L<AnyEvent::BDB>, L<BDB>
		711
		712	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
		713	IO::AIO and AnyEvent together.
		714
		715	=item L<IO::Lambda>
		716
		717	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
501		718
502	=back	719	=back
503		720
504	=cut	721	=cut
505		722
…		…
508	no warnings;	725	no warnings;
509	use strict;	726	use strict;
510		727
511	use Carp;	728	use Carp;
512		729
513	our $VERSION = '3.3';	730	our $VERSION = '4.03';
514	our $MODEL;	731	our $MODEL;
515		732
516	our $AUTOLOAD;	733	our $AUTOLOAD;
517	our @ISA;	734	our @ISA;
518		735
519	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	736	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
520		737
521	our @REGISTRY;	738	our @REGISTRY;
522		739
		740	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2)
		741
		742	{
		743	my $idx;
		744	$PROTOCOL{$_} = ++$idx
		745	for split /\s,\s/, $ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
		746	}
		747
523	my @models = (	748	my @models = (
524	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
525	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
526	[EV:: => AnyEvent::Impl::EV::],	749	[EV:: => AnyEvent::Impl::EV::],
527	[Event:: => AnyEvent::Impl::Event::],	750	[Event:: => AnyEvent::Impl::Event::],
528	[Glib:: => AnyEvent::Impl::Glib::],
529	[Tk:: => AnyEvent::Impl::Tk::],	751	[Tk:: => AnyEvent::Impl::Tk::],
530	[Wx:: => AnyEvent::Impl::POE::],	752	[Wx:: => AnyEvent::Impl::POE::],
531	[Prima:: => AnyEvent::Impl::POE::],	753	[Prima:: => AnyEvent::Impl::POE::],
532	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	754	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
533	# everything below here will not be autoprobed as the pureperl backend should work everywhere	755	# everything below here will not be autoprobed as the pureperl backend should work everywhere
		756	[Glib:: => AnyEvent::Impl::Glib::],
534	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	757	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
535	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	758	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
536	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	759	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
537	);	760	);
538		761
539	our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY);	762	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);
		763
		764	our @post_detect;
		765
		766	sub post_detect(&) {
		767	my ($cb) = @_;
		768
		769	if ($MODEL) {
		770	$cb->();
		771
		772	1
		773	} else {
		774	push @post_detect, $cb;
		775
		776	defined wantarray
		777	? bless \$cb, "AnyEvent::Util::PostDetect"
		778	: ()
		779	}
		780	}
		781
		782	sub AnyEvent::Util::PostDetect::DESTROY {
		783	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		784	}
540		785
541	sub detect() {	786	sub detect() {
542	unless ($MODEL) {	787	unless ($MODEL) {
543	no strict 'refs';	788	no strict 'refs';
544		789
…		…
578	last;	823	last;
579	}	824	}
580	}	825	}
581		826
582	$MODEL	827	$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.";	828	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
584	}	829	}
585	}	830	}
586		831
587	unshift @ISA, $MODEL;	832	unshift @ISA, $MODEL;
588	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	833	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		834
		835	(shift @post_detect)->() while @post_detect;
589	}	836	}
590		837
591	$MODEL	838	$MODEL
592	}	839	}
593		840
…		…
603	$class->$func (@_);	850	$class->$func (@_);
604	}	851	}
605		852
606	package AnyEvent::Base;	853	package AnyEvent::Base;
607		854
608	# default implementation for ->condvar, ->wait, ->broadcast	855	# default implementation for ->condvar
609		856
610	sub condvar {	857	sub condvar {
611	bless \my $flag, "AnyEvent::Base::CondVar"	858	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	}	859	}
621		860
622	# default implementation for ->signal	861	# default implementation for ->signal
623		862
624	our %SIG_CB;	863	our %SIG_CB;
…		…
698	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	937	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
699		938
700	undef $CHLD_W unless keys %PID_CB;	939	undef $CHLD_W unless keys %PID_CB;
701	}	940	}
702		941
		942	package AnyEvent::CondVar;
		943
		944	our @ISA = AnyEvent::CondVar::Base::;
		945
		946	package AnyEvent::CondVar::Base;
		947
		948	use overload
		949	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		950	fallback => 1;
		951
		952	sub _send {
		953	# nop
		954	}
		955
		956	sub send {
		957	my $cv = shift;
		958	$cv->{_ae_sent} = [@_];
		959	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		960	$cv->_send;
		961	}
		962
		963	sub croak {
		964	$_[0]{_ae_croak} = $_[1];
		965	$_[0]->send;
		966	}
		967
		968	sub ready {
		969	$_[0]{_ae_sent}
		970	}
		971
		972	sub _wait {
		973	AnyEvent->one_event while !$_[0]{_ae_sent};
		974	}
		975
		976	sub recv {
		977	$_[0]->_wait;
		978
		979	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		980	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		981	}
		982
		983	sub cb {
		984	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		985	$_[0]{_ae_cb}
		986	}
		987
		988	sub begin {
		989	++$_[0]{_ae_counter};
		990	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		991	}
		992
		993	sub end {
		994	return if --$_[0]{_ae_counter};
		995	&{ $_[0]{_ae_end_cb} \|\| sub { $_[0]->send } };
		996	}
		997
		998	# undocumented/compatibility with pre-3.4
		999	*broadcast = \&send;
		1000	*wait = \&_wait;
		1001
703	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1002	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
704		1003
705	This is an advanced topic that you do not normally need to use AnyEvent in	1004	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	1005	a module. This section is only of use to event loop authors who want to
707	provide AnyEvent compatibility.	1006	provide AnyEvent compatibility.
…		…
763	model it chooses.	1062	model it chooses.
764		1063
765	=item C<PERL_ANYEVENT_MODEL>	1064	=item C<PERL_ANYEVENT_MODEL>
766		1065
767	This can be used to specify the event model to be used by AnyEvent, before	1066	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	1067	auto detection and -probing kicks in. It must be a string consisting
769	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1068	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,	1069	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	1070	used as event model. If it fails to load AnyEvent will proceed with
772	autodetection and -probing.	1071	auto detection and -probing.
773		1072
774	This functionality might change in future versions.	1073	This functionality might change in future versions.
775		1074
776	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1075	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
777	could start your program like this:	1076	could start your program like this:
778		1077
779	PERL_ANYEVENT_MODEL=Perl perl ...	1078	PERL_ANYEVENT_MODEL=Perl perl ...
		1079
		1080	=item C<PERL_ANYEVENT_PROTOCOLS>
		1081
		1082	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1083	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1084	of auto probing).
		1085
		1086	Must be set to a comma-separated list of protocols or address families,
		1087	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1088	used, and preference will be given to protocols mentioned earlier in the
		1089	list.
		1090
		1091	This variable can effectively be used for denial-of-service attacks
		1092	against local programs (e.g. when setuid), although the impact is likely
		1093	small, as the program has to handle connection errors already-
		1094
		1095	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1096	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1097	- only support IPv4, never try to resolve or contact IPv6
		1098	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1099	IPv6, but prefer IPv6 over IPv4.
		1100
		1101	=item C<PERL_ANYEVENT_EDNS0>
		1102
		1103	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1104	for DNS. This extension is generally useful to reduce DNS traffic, but
		1105	some (broken) firewalls drop such DNS packets, which is why it is off by
		1106	default.
		1107
		1108	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1109	EDNS0 in its DNS requests.
780		1110
781	=back	1111	=back
782		1112
783	=head1 EXAMPLE PROGRAM	1113	=head1 EXAMPLE PROGRAM
784		1114
…		…
795	poll => 'r',	1125	poll => 'r',
796	cb => sub {	1126	cb => sub {
797	warn "io event <$_[0]>\n"; # will always output <r>	1127	warn "io event <$_[0]>\n"; # will always output <r>
798	chomp (my $input = <STDIN>); # read a line	1128	chomp (my $input = <STDIN>); # read a line
799	warn "read: $input\n"; # output what has been read	1129	warn "read: $input\n"; # output what has been read
800	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1130	$cv->send if $input =~ /^q/i; # quit program if /^q/i
801	},	1131	},
802	);	1132	);
803		1133
804	my $time_watcher; # can only be used once	1134	my $time_watcher; # can only be used once
805		1135
…		…
810	});	1140	});
811	}	1141	}
812		1142
813	new_timer; # create first timer	1143	new_timer; # create first timer
814		1144
815	$cv->wait; # wait until user enters /^q/i	1145	$cv->recv; # wait until user enters /^q/i
816		1146
817	=head1 REAL-WORLD EXAMPLE	1147	=head1 REAL-WORLD EXAMPLE
818		1148
819	Consider the L<Net::FCP> module. It features (among others) the following	1149	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:	1150	API calls, which are to freenet what HTTP GET requests are to http:
…		…
870	syswrite $txn->{fh}, $txn->{request}	1200	syswrite $txn->{fh}, $txn->{request}
871	or die "connection or write error";	1201	or die "connection or write error";
872	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1202	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
873		1203
874	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1204	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:	1205	result and signals any possible waiters that the request has finished:
876		1206
877	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1207	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
878		1208
879	if (end-of-file or data complete) {	1209	if (end-of-file or data complete) {
880	$txn->{result} = $txn->{buf};	1210	$txn->{result} = $txn->{buf};
881	$txn->{finished}->broadcast;	1211	$txn->{finished}->send;
882	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1212	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
883	}	1213	}
884		1214
885	The C<result> method, finally, just waits for the finished signal (if the	1215	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	1216	request was already finished, it doesn't wait, of course, and returns the
887	data:	1217	data:
888		1218
889	$txn->{finished}->wait;	1219	$txn->{finished}->recv;
890	return $txn->{result};	1220	return $txn->{result};
891		1221
892	The actual code goes further and collects all errors (C<die>s, exceptions)	1222	The actual code goes further and collects all errors (C<die>s, exceptions)
893	that occured during request processing. The C<result> method detects	1223	that occurred during request processing. The C<result> method detects
894	whether an exception as thrown (it is stored inside the $txn object)	1224	whether an exception as thrown (it is stored inside the $txn object)
895	and just throws the exception, which means connection errors and other	1225	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	1226	problems get reported tot he code that tries to use the result, not in a
897	random callback.	1227	random callback.
898		1228
…		…
929		1259
930	my $quit = AnyEvent->condvar;	1260	my $quit = AnyEvent->condvar;
931		1261
932	$fcp->txn_client_get ($url)->cb (sub {	1262	$fcp->txn_client_get ($url)->cb (sub {
933	...	1263	...
934	$quit->broadcast;	1264	$quit->send;
935	});	1265	});
936		1266
937	$quit->wait;	1267	$quit->recv;
938		1268
939		1269
940	=head1 BENCHMARKS	1270	=head1 BENCHMARKS
941		1271
942	To give you an idea of the performance and overheads that AnyEvent adds	1272	To give you an idea of the performance and overheads that AnyEvent adds
…		…
944	of various event loops I prepared some benchmarks.	1274	of various event loops I prepared some benchmarks.
945		1275
946	=head2 BENCHMARKING ANYEVENT OVERHEAD	1276	=head2 BENCHMARKING ANYEVENT OVERHEAD
947		1277
948	Here is a benchmark of various supported event models used natively and	1278	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	1279	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,	1280	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.	1281	which it is), lets them fire exactly once and destroys them again.
952		1282
953	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1283	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
954	distribution.	1284	distribution.
…		…
971	all watchers, to avoid adding memory overhead. That means closure creation	1301	all watchers, to avoid adding memory overhead. That means closure creation
972	and memory usage is not included in the figures.	1302	and memory usage is not included in the figures.
973		1303
974	I<invoke> is the time, in microseconds, used to invoke a simple	1304	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	1305	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	1306	invoked "watcher" times, it would C<< ->send >> a condvar once to
977	signal the end of this phase.	1307	signal the end of this phase.
978		1308
979	I<destroy> is the time, in microseconds, that it takes to destroy a single	1309	I<destroy> is the time, in microseconds, that it takes to destroy a single
980	watcher.	1310	watcher.
981		1311
…		…
1041	file descriptor is dup()ed for each watcher. This shows that the dup()	1371	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	1372	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	1373	hidden memory cost inside the kernel which is not reflected in the figures
1044	above).	1374	above).
1045		1375
1046	C<POE>, regardless of underlying event loop (whether using its pure	1376	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	1377	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	1378	be tested because it wasn't working) shows abysmal performance and
1049	and memory usage: Watchers use almost 30 times as much memory as	1379	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	1380	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	1381	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	1382	invocation speed is almost 900 times slower than with AnyEvent's pure perl
		1383	implementation.
		1384
1053	implementation. The design of the POE adaptor class in AnyEvent can not	1385	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	1386	for the performance issues, though, as session creation overhead is
1055	to execution of the state machine, which is coded pretty optimally within	1387	small compared to execution of the state machine, which is coded pretty
1056	L<AnyEvent::Impl::POE>. POE simply seems to be abysmally slow.	1388	optimally within L<AnyEvent::Impl::POE> (and while everybody agrees that
		1389	using multiple sessions is not a good approach, especially regarding
		1390	memory usage, even the author of POE could not come up with a faster
		1391	design).
1057		1392
1058	=head3 Summary	1393	=head3 Summary
1059		1394
1060	=over 4	1395	=over 4
1061		1396
…		…
1072		1407
1073	=back	1408	=back
1074		1409
1075	=head2 BENCHMARKING THE LARGE SERVER CASE	1410	=head2 BENCHMARKING THE LARGE SERVER CASE
1076		1411
1077	This benchmark atcually benchmarks the event loop itself. It works by	1412	This benchmark actually benchmarks the event loop itself. It works by
1078	creating a number of "servers": each server consists of a socketpair, a	1413	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	1414	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	1415	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".	1416	watcher reads a byte it will write that byte to a random other "server".
1082		1417
1083	The effect is that there will be a lot of I/O watchers, only part of which	1418	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	1419	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	1420	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	1421	timeout is reset each time something is read because that reflects how
1087	most timeouts work (and puts extra pressure on the event loops).	1422	most timeouts work (and puts extra pressure on the event loops).
1088		1423
1089	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1424	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	1425	(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.	1426	connections, most of which are idle at any one point in time.
1092		1427
1093	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1428	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1094	distribution.	1429	distribution.
…		…
1096	=head3 Explanation of the columns	1431	=head3 Explanation of the columns
1097		1432
1098	I<sockets> is the number of sockets, and twice the number of "servers" (as	1433	I<sockets> is the number of sockets, and twice the number of "servers" (as
1099	each server has a read and write socket end).	1434	each server has a read and write socket end).
1100		1435
1101	I<create> is the time it takes to create a socketpair (which is	1436	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.	1437	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1103		1438
1104	I<request>, the most important value, is the time it takes to handle a	1439	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	1440	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	1441	it to another server. This includes deleting the old timeout and creating
…		…
1140		1475
1141	=head3 Summary	1476	=head3 Summary
1142		1477
1143	=over 4	1478	=over 4
1144		1479
1145	=item * The pure perl implementation performs extremely well, considering	1480	=item * The pure perl implementation performs extremely well.
1146	that it uses select.
1147		1481
1148	=item * Avoid Glib or POE in large projects where performance matters.	1482	=item * Avoid Glib or POE in large projects where performance matters.
1149		1483
1150	=back	1484	=back
1151		1485
…		…
1180	speed most when you have lots of watchers, not when you only have a few of	1514	speed most when you have lots of watchers, not when you only have a few of
1181	them).	1515	them).
1182		1516
1183	EV is again fastest.	1517	EV is again fastest.
1184		1518
1185	The C-based event loops Event and Glib come in second this time, as the	1519	Perl again comes second. It is noticeably faster than the C-based event
1186	overhead of running an iteration is much smaller in C than in Perl (little	1520	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	1521	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		1522
1192	POE also performs much better in this case, but is is still far behind the	1523	POE also performs much better in this case, but is is still far behind the
1193	others.	1524	others.
1194		1525
1195	=head3 Summary	1526	=head3 Summary
…		…
1203		1534
1204		1535
1205	=head1 FORK	1536	=head1 FORK
1206		1537
1207	Most event libraries are not fork-safe. The ones who are usually are	1538	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.	1539	because they rely on inefficient but fork-safe C<select> or C<poll>
		1540	calls. Only L<EV> is fully fork-aware.
1209		1541
1210	If you have to fork, you must either do so I<before> creating your first	1542	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.	1543	watcher OR you must not use AnyEvent at all in the child.
1212		1544
1213		1545
…		…
1225		1557
1226	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1558	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1227		1559
1228	use AnyEvent;	1560	use AnyEvent;
1229		1561
		1562	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
		1563	be used to probe what backend is used and gain other information (which is
		1564	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
		1565
1230		1566
1231	=head1 SEE ALSO	1567	=head1 SEE ALSO
1232		1568
1233	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,	1569	Utility functions: L<AnyEvent::Util>.
1234	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,	1570
		1571	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1235	L<Event::Lib>, L<Qt>, L<POE>.	1572	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1236		1573
1237	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,	1574	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1238	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,	1575	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>,	1576	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1240	L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>.	1577	L<AnyEvent::Impl::POE>.
1241		1578
		1579	Non-blocking file handles, sockets, TCP clients and
		1580	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1581
		1582	Asynchronous DNS: L<AnyEvent::DNS>.
		1583
		1584	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
		1585
1242	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1586	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1243		1587
1244		1588
1245	=head1 AUTHOR	1589	=head1 AUTHOR
1246		1590
1247	Marc Lehmann <schmorp@schmorp.de>	1591	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 1.133 by root, Sun May 25 03:44:03 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 1.133 by root, Sun May 25 03:44:03 2008 UTC