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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.105 by root, Thu May 1 12:35:54 2008 UTC vs.
Revision 1.134 by root, Sun May 25 04:44:04 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
…		…
78	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>
79	module.	79	module.
80		80
81	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
82	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
83	following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>,	83	following modules is already loaded: L<EV>,
84	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>,
85	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
86	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
87	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
88	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
…		…
108		108
109	=head1 WATCHERS	109	=head1 WATCHERS
110		110
111	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
112	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
113	the callback to call, the filehandle to watch, etc.	113	the callback to call, the file handle to watch, etc.
114		114
115	These watchers are normal Perl objects with normal Perl lifetime. After	115	These watchers are normal Perl objects with normal Perl lifetime. After
116	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
117	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
118	is in control).	118	is in control).
…		…
237		237
238	Although the callback might get passed parameters, their value and	238	Although the callback might get passed parameters, their value and
239	presence is undefined and you cannot rely on them. Portable AnyEvent	239	presence is undefined and you cannot rely on them. Portable AnyEvent
240	callbacks cannot use arguments passed to signal watcher callbacks.	240	callbacks cannot use arguments passed to signal watcher callbacks.
241		241
242	Multiple signal occurances can be clumped together into one callback	242	Multiple signal occurrences can be clumped together into one callback
243	invocation, and callback invocation will be synchronous. synchronous means	243	invocation, and callback invocation will be synchronous. Synchronous means
244	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,
245	but it is guarenteed not to interrupt any other callbacks.	245	but it is guaranteed not to interrupt any other callbacks.
246		246
247	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
248	between multiple watchers.	248	between multiple watchers.
249		249
250	This watcher might use C<%SIG>, so programs overwriting those signals	250	This watcher might use C<%SIG>, so programs overwriting those signals
…		…
279		279
280	Example: fork a process and wait for it	280	Example: fork a process and wait for it
281		281
282	my $done = AnyEvent->condvar;	282	my $done = AnyEvent->condvar;
283		283
284	AnyEvent::detect; # force event module to be initialised
285
286	my $pid = fork or exit 5;	284	my $pid = fork or exit 5;
287		285
288	my $w = AnyEvent->child (	286	my $w = AnyEvent->child (
289	pid => $pid,	287	pid => $pid,
290	cb => sub {	288	cb => sub {
291	my ($pid, $status) = @_;	289	my ($pid, $status) = @_;
292	warn "pid $pid exited with status $status";	290	warn "pid $pid exited with status $status";
293	$done->broadcast;	291	$done->send;
294	},	292	},
295	);	293	);
296		294
297	# do something else, then wait for process exit	295	# do something else, then wait for process exit
298	$done->wait;	296	$done->recv;
299		297
300	=head2 CONDITION VARIABLES	298	=head2 CONDITION VARIABLES
301		299
302	If you are familiar with some event loops you will know that all of them	300	If you are familiar with some event loops you will know that all of them
303	require you to run some blocking "loop", "run" or similar function that	301	require you to run some blocking "loop", "run" or similar function that
…		…
312	Condition variables can be created by calling the C<< AnyEvent->condvar	310	Condition variables can be created by calling the C<< AnyEvent->condvar
313	>> method, usually without arguments. The only argument pair allowed is	311	>> method, usually without arguments. The only argument pair allowed is
314	C<cb>, which specifies a callback to be called when the condition variable	312	C<cb>, which specifies a callback to be called when the condition variable
315	becomes true.	313	becomes true.
316		314
317	After creation, the conditon variable is "false" until it becomes "true"	315	After creation, the condition variable is "false" until it becomes "true"
318	by calling the C<broadcast> method.	316	by calling the C<send> method (or calling the condition variable as if it
		317	were a callback).
319		318
320	Condition variables are similar to callbacks, except that you can	319	Condition variables are similar to callbacks, except that you can
321	optionally wait for them. They can also be called merge points - points	320	optionally wait for them. They can also be called merge points - points
322	in time where multiple outstandign events have been processed. And yet	321	in time where multiple outstanding events have been processed. And yet
323	another way to call them is transations - each condition variable can be	322	another way to call them is transactions - each condition variable can be
324	used to represent a transaction, which finishes at some point and delivers	323	used to represent a transaction, which finishes at some point and delivers
325	a result.	324	a result.
326		325
327	Condition variables are very useful to signal that something has finished,	326	Condition variables are very useful to signal that something has finished,
328	for example, if you write a module that does asynchronous http requests,	327	for example, if you write a module that does asynchronous http requests,
329	then a condition variable would be the ideal candidate to signal the	328	then a condition variable would be the ideal candidate to signal the
330	availability of results. The user can either act when the callback is	329	availability of results. The user can either act when the callback is
331	called or can synchronously C<< ->wait >> for the results.	330	called or can synchronously C<< ->recv >> for the results.
332		331
333	You can also use them to simulate traditional event loops - for example,	332	You can also use them to simulate traditional event loops - for example,
334	you can block your main program until an event occurs - for example, you	333	you can block your main program until an event occurs - for example, you
335	could C<< ->wait >> in your main program until the user clicks the Quit	334	could C<< ->recv >> in your main program until the user clicks the Quit
336	button of your app, which would C<< ->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 pieces 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	Condition variables are represented by hash refs in perl, and the keys	343	Condition variables are represented by hash refs in perl, and the keys
…		…
346	easy (it is often useful to build your own transaction class on top of	345	easy (it is often useful to build your own transaction class on top of
347	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call	346	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
348	it's C<new> method in your own C<new> method.	347	it's C<new> method in your own C<new> method.
349		348
350	There are two "sides" to a condition variable - the "producer side" which	349	There are two "sides" to a condition variable - the "producer side" which
351	eventually calls C<< -> broadcast >>, and the "consumer side", which waits	350	eventually calls C<< -> send >>, and the "consumer side", which waits
352	for the broadcast to occur.	351	for the send to occur.
353		352
354	Example:	353	Example: wait for a timer.
355		354
356	# wait till the result is ready	355	# wait till the result is ready
357	my $result_ready = AnyEvent->condvar;	356	my $result_ready = AnyEvent->condvar;
358		357
359	# do something such as adding a timer	358	# do something such as adding a timer
360	# or socket watcher the calls $result_ready->broadcast	359	# or socket watcher the calls $result_ready->send
361	# when the "result" is ready.	360	# when the "result" is ready.
362	# in this case, we simply use a timer:	361	# in this case, we simply use a timer:
363	my $w = AnyEvent->timer (	362	my $w = AnyEvent->timer (
364	after => 1,	363	after => 1,
365	cb => sub { $result_ready->broadcast },	364	cb => sub { $result_ready->send },
366	);	365	);
367		366
368	# this "blocks" (while handling events) till the callback	367	# this "blocks" (while handling events) till the callback
369	# calls broadcast	368	# calls send
370	$result_ready->wait;	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;
371		377
372	=head3 METHODS FOR PRODUCERS	378	=head3 METHODS FOR PRODUCERS
373		379
374	These methods should only be used by the producing side, i.e. the	380	These methods should only be used by the producing side, i.e. the
375	code/module that eventually broadcasts the signal. Note that it is also	381	code/module that eventually sends the signal. Note that it is also
376	the producer side which creates the condvar in most cases, but it isn't	382	the producer side which creates the condvar in most cases, but it isn't
377	uncommon for the consumer to create it as well.	383	uncommon for the consumer to create it as well.
378		384
379	=over 4	385	=over 4
380		386
381	=item $cv->broadcast (...)	387	=item $cv->send (...)
382		388
383	Flag the condition as ready - a running C<< ->wait >> and all further	389	Flag the condition as ready - a running C<< ->recv >> and all further
384	calls to C<wait> will (eventually) return after this method has been	390	calls to C<recv> will (eventually) return after this method has been
385	called. If nobody is waiting the broadcast will be remembered.	391	called. If nobody is waiting the send will be remembered.
386		392
387	If a callback has been set on the condition variable, it is called	393	If a callback has been set on the condition variable, it is called
388	immediately from within broadcast.	394	immediately from within send.
389		395
390	Any arguments passed to the C<broadcast> call will be returned by all	396	Any arguments passed to the C<send> call will be returned by all
391	future C<< ->wait >> calls.	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>.
392		401
393	=item $cv->croak ($error)	402	=item $cv->croak ($error)
394		403
395	Similar to broadcast, but causes all call's wait C<< ->wait >> to invoke	404	Similar to send, but causes all call's to C<< ->recv >> to invoke
396	C<Carp::croak> with the given error message/object/scalar.	405	C<Carp::croak> with the given error message/object/scalar.
397		406
398	This can be used to signal any errors to the condition variable	407	This can be used to signal any errors to the condition variable
399	user/consumer.	408	user/consumer.
400		409
401	=item $cv->begin ([group callback])	410	=item $cv->begin ([group callback])
402		411
403	=item $cv->end	412	=item $cv->end
		413
		414	These two methods are EXPERIMENTAL and MIGHT CHANGE.
404		415
405	These two methods can be used to combine many transactions/events into	416	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	417	one. For example, a function that pings many hosts in parallel might want
407	to use a condition variable for the whole process.	418	to use a condition variable for the whole process.
408		419
409	Every call to C<< ->begin >> will increment a counter, and every call to	420	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	421	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	422	>>, the (last) callback passed to C<begin> will be executed. That callback
412	is I<supposed> to call C<< ->broadcast >>, but that is not required. If no	423	is I<supposed> to call C<< ->send >>, but that is not required. If no
413	callback was set, C<broadcast> will be called without any arguments.	424	callback was set, C<send> will be called without any arguments.
414		425
415	Let's clarify this with the ping example:	426	Let's clarify this with the ping example:
416		427
417	my $cv = AnyEvent->condvar;	428	my $cv = AnyEvent->condvar;
418		429
419	my %result;	430	my %result;
420	$cv->begin (sub { $cv->broadcast (\%result) });	431	$cv->begin (sub { $cv->send (\%result) });
421		432
422	for my $host (@list_of_hosts) {	433	for my $host (@list_of_hosts) {
423	$cv->begin;	434	$cv->begin;
424	ping_host_then_call_callback $host, sub {	435	ping_host_then_call_callback $host, sub {
425	$result{$host} = ...;	436	$result{$host} = ...;
…		…
428	}	439	}
429		440
430	$cv->end;	441	$cv->end;
431		442
432	This code fragment supposedly pings a number of hosts and calls	443	This code fragment supposedly pings a number of hosts and calls
433	C<broadcast> after results for all then have have been gathered - in any	444	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	445	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	446	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	447	it. Since C<begin> and C<end> only maintain a counter, the order in which
437	results arrive is not relevant.	448	results arrive is not relevant.
438		449
439	There is an additional bracketing call to C<begin> and C<end> outside the	450	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	451	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	452	to be called once the counter reaches C<0>, and second, it ensures that
442	broadcast is called even when C<no> hosts are being pinged (the loop	453	C<send> is called even when C<no> hosts are being pinged (the loop
443	doesn't execute once).	454	doesn't execute once).
444		455
445	This is the general pattern when you "fan out" into multiple subrequests:	456	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>	457	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	458	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>.	459	C<begin> and for each subrequest you finish, call C<end>.
449		460
450	=back	461	=back
451		462
452	=head3 METHODS FOR CONSUMERS	463	=head3 METHODS FOR CONSUMERS
453		464
454	These methods should only be used by the consuming side, i.e. the	465	These methods should only be used by the consuming side, i.e. the
455	code awaits the condition.	466	code awaits the condition.
456		467
457	=item $cv->wait	468	=over 4
458		469
		470	=item $cv->recv
		471
459	Wait (blocking if necessary) until the C<< ->broadcast >> or C<< ->croak	472	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
460	>> methods have been called on c<$cv>, while servicing other watchers	473	>> methods have been called on c<$cv>, while servicing other watchers
461	normally.	474	normally.
462		475
463	You can only wait once on a condition - additional calls are valid but	476	You can only wait once on a condition - additional calls are valid but
464	will return immediately.	477	will return immediately.
465		478
466	If an error condition has been set by calling C<< ->croak >>, then this	479	If an error condition has been set by calling C<< ->croak >>, then this
467	function will call C<croak>.	480	function will call C<croak>.
468		481
469	In list context, all parameters passed to C<broadcast> will be returned,	482	In list context, all parameters passed to C<send> will be returned,
470	in scalar context only the first one will be returned.	483	in scalar context only the first one will be returned.
471		484
472	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
473	(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
474	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
475	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
476	condition variables with some kind of request results and supporting	489	condition variables with some kind of request results and supporting
477	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,
478	while still suppporting blocking waits if the caller so desires).	491	while still supporting blocking waits if the caller so desires).
479		492
480	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
481	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
482	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	495	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
483	can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and	496	can supply.
484	L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
485	from different coroutines, however).
486		497
		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).
		503
487	You can ensure that C<< -wait >> never blocks by setting a callback and	504	You can ensure that C<< -recv >> never blocks by setting a callback and
488	only calling C<< ->wait >> from within that callback (or at a later	505	only calling C<< ->recv >> from within that callback (or at a later
489	time). This will work even when the event loop does not support blocking	506	time). This will work even when the event loop does not support blocking
490	waits otherwise.	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 = $cv->cb ([new callback])
		515
		516	This is a mutator function that returns the callback set and optionally
		517	replaces it before doing so.
		518
		519	The callback will be called when the condition becomes "true", i.e. when
		520	C<send> or C<croak> are called. Calling C<recv> inside the callback
		521	or at any later time is guaranteed not to block.
491		522
492	=back	523	=back
493		524
494	=head1 GLOBAL VARIABLES AND FUNCTIONS	525	=head1 GLOBAL VARIABLES AND FUNCTIONS
495		526
…		…
503	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	534	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
504	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	535	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
505		536
506	The known classes so far are:	537	The known classes so far are:
507		538
508	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
509	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
510	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).	539	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
511	AnyEvent::Impl::Event based on Event, second best choice.	540	AnyEvent::Impl::Event based on Event, second best choice.
512	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	541	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
513	AnyEvent::Impl::Glib based on Glib, third-best choice.	542	AnyEvent::Impl::Glib based on Glib, third-best choice.
514	AnyEvent::Impl::Tk based on Tk, very bad choice.	543	AnyEvent::Impl::Tk based on Tk, very bad choice.
…		…
531	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	560	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
532	if necessary. You should only call this function right before you would	561	if necessary. You should only call this function right before you would
533	have created an AnyEvent watcher anyway, that is, as late as possible at	562	have created an AnyEvent watcher anyway, that is, as late as possible at
534	runtime.	563	runtime.
535		564
		565	=item $guard = AnyEvent::post_detect { BLOCK }
		566
		567	Arranges for the code block to be executed as soon as the event model is
		568	autodetected (or immediately if this has already happened).
		569
		570	If called in scalar or list context, then it creates and returns an object
		571	that automatically removes the callback again when it is destroyed. See
		572	L<Coro::BDB> for a case where this is useful.
		573
		574	=item @AnyEvent::post_detect
		575
		576	If there are any code references in this array (you can C<push> to it
		577	before or after loading AnyEvent), then they will called directly after
		578	the event loop has been chosen.
		579
		580	You should check C<$AnyEvent::MODEL> before adding to this array, though:
		581	if it contains a true value then the event loop has already been detected,
		582	and the array will be ignored.
		583
		584	Best use C<AnyEvent::post_detect { BLOCK }> instead.
		585
536	=back	586	=back
537		587
538	=head1 WHAT TO DO IN A MODULE	588	=head1 WHAT TO DO IN A MODULE
539		589
540	As a module author, you should C<use AnyEvent> and call AnyEvent methods	590	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
543	Be careful when you create watchers in the module body - AnyEvent will	593	Be careful when you create watchers in the module body - AnyEvent will
544	decide which event module to use as soon as the first method is called, so	594	decide which event module to use as soon as the first method is called, so
545	by calling AnyEvent in your module body you force the user of your module	595	by calling AnyEvent in your module body you force the user of your module
546	to load the event module first.	596	to load the event module first.
547		597
548	Never call C<< ->wait >> on a condition variable unless you I<know> that	598	Never call C<< ->recv >> on a condition variable unless you I<know> that
549	the C<< ->broadcast >> method has been called on it already. This is	599	the C<< ->send >> method has been called on it already. This is
550	because it will stall the whole program, and the whole point of using	600	because it will stall the whole program, and the whole point of using
551	events is to stay interactive.	601	events is to stay interactive.
552		602
553	It is fine, however, to call C<< ->wait >> when the user of your module	603	It is fine, however, to call C<< ->recv >> when the user of your module
554	requests it (i.e. if you create a http request object ad have a method	604	requests it (i.e. if you create a http request object ad have a method
555	called C<results> that returns the results, it should call C<< ->wait >>	605	called C<results> that returns the results, it should call C<< ->recv >>
556	freely, as the user of your module knows what she is doing. always).	606	freely, as the user of your module knows what she is doing. always).
557		607
558	=head1 WHAT TO DO IN THE MAIN PROGRAM	608	=head1 WHAT TO DO IN THE MAIN PROGRAM
559		609
560	There will always be a single main program - the only place that should	610	There will always be a single main program - the only place that should
…		…
562		612
563	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	613	If it doesn't care, it can just "use AnyEvent" and use it itself, or not
564	do anything special (it does not need to be event-based) and let AnyEvent	614	do anything special (it does not need to be event-based) and let AnyEvent
565	decide which implementation to chose if some module relies on it.	615	decide which implementation to chose if some module relies on it.
566		616
567	If the main program relies on a specific event model. For example, in	617	If the main program relies on a specific event model - for example, in
568	Gtk2 programs you have to rely on the Glib module. You should load the	618	Gtk2 programs you have to rely on the Glib module - you should load the
569	event module before loading AnyEvent or any module that uses it: generally	619	event module before loading AnyEvent or any module that uses it: generally
570	speaking, you should load it as early as possible. The reason is that	620	speaking, you should load it as early as possible. The reason is that
571	modules might create watchers when they are loaded, and AnyEvent will	621	modules might create watchers when they are loaded, and AnyEvent will
572	decide on the event model to use as soon as it creates watchers, and it	622	decide on the event model to use as soon as it creates watchers, and it
573	might chose the wrong one unless you load the correct one yourself.	623	might chose the wrong one unless you load the correct one yourself.
574		624
575	You can chose to use a rather inefficient pure-perl implementation by	625	You can chose to use a pure-perl implementation by loading the
576	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	626	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
577	behaviour everywhere, but letting AnyEvent chose is generally better.	627	everywhere, but letting AnyEvent chose the model is generally better.
		628
		629	=head2 MAINLOOP EMULATION
		630
		631	Sometimes (often for short test scripts, or even standalone programs who
		632	only want to use AnyEvent), you do not want to run a specific event loop.
		633
		634	In that case, you can use a condition variable like this:
		635
		636	AnyEvent->condvar->recv;
		637
		638	This has the effect of entering the event loop and looping forever.
		639
		640	Note that usually your program has some exit condition, in which case
		641	it is better to use the "traditional" approach of storing a condition
		642	variable somewhere, waiting for it, and sending it when the program should
		643	exit cleanly.
		644
578		645
579	=head1 OTHER MODULES	646	=head1 OTHER MODULES
580		647
581	The following is a non-exhaustive list of additional modules that use	648	The following is a non-exhaustive list of additional modules that use
582	AnyEvent and can therefore be mixed easily with other AnyEvent modules	649	AnyEvent and can therefore be mixed easily with other AnyEvent modules
…		…
594		661
595	Provide read and write buffers and manages watchers for reads and writes.	662	Provide read and write buffers and manages watchers for reads and writes.
596		663
597	=item L<AnyEvent::Socket>	664	=item L<AnyEvent::Socket>
598		665
599	Provides a means to do non-blocking connects, accepts etc.	666	Provides various utility functions for (internet protocol) sockets,
		667	addresses and name resolution. Also functions to create non-blocking tcp
		668	connections or tcp servers, with IPv6 and SRV record support and more.
		669
		670	=item L<AnyEvent::DNS>
		671
		672	Provides rich asynchronous DNS resolver capabilities.
600		673
601	=item L<AnyEvent::HTTPD>	674	=item L<AnyEvent::HTTPD>
602		675
603	Provides a simple web application server framework.	676	Provides a simple web application server framework.
604
605	=item L<AnyEvent::DNS>
606
607	Provides asynchronous DNS resolver capabilities, beyond what
608	L<AnyEvent::Util> offers.
609		677
610	=item L<AnyEvent::FastPing>	678	=item L<AnyEvent::FastPing>
611		679
612	The fastest ping in the west.	680	The fastest ping in the west.
613		681
…		…
628		696
629	High level API for event-based execution flow control.	697	High level API for event-based execution flow control.
630		698
631	=item L<Coro>	699	=item L<Coro>
632		700
633	Has special support for AnyEvent.	701	Has special support for AnyEvent via L<Coro::AnyEvent>.
		702
		703	=item L<AnyEvent::AIO>, L<IO::AIO>
		704
		705	Truly asynchronous I/O, should be in the toolbox of every event
		706	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
		707	together.
		708
		709	=item L<AnyEvent::BDB>, L<BDB>
		710
		711	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
		712	IO::AIO and AnyEvent together.
634		713
635	=item L<IO::Lambda>	714	=item L<IO::Lambda>
636		715
637	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	716	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
638
639	=item L<IO::AIO>
640
641	Truly asynchronous I/O, should be in the toolbox of every event
642	programmer. Can be trivially made to use AnyEvent.
643
644	=item L<BDB>
645
646	Truly asynchronous Berkeley DB access. Can be trivially made to use
647	AnyEvent.
648		717
649	=back	718	=back
650		719
651	=cut	720	=cut
652		721
…		…
655	no warnings;	724	no warnings;
656	use strict;	725	use strict;
657		726
658	use Carp;	727	use Carp;
659		728
660	our $VERSION = '3.3';	729	our $VERSION = '4.03';
661	our $MODEL;	730	our $MODEL;
662		731
663	our $AUTOLOAD;	732	our $AUTOLOAD;
664	our @ISA;	733	our @ISA;
665		734
666	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	735	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
667		736
668	our @REGISTRY;	737	our @REGISTRY;
669		738
		739	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2)
		740
		741	{
		742	my $idx;
		743	$PROTOCOL{$_} = ++$idx
		744	for split /\s,\s/, $ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
		745	}
		746
670	my @models = (	747	my @models = (
671	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
672	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
673	[EV:: => AnyEvent::Impl::EV::],	748	[EV:: => AnyEvent::Impl::EV::],
674	[Event:: => AnyEvent::Impl::Event::],	749	[Event:: => AnyEvent::Impl::Event::],
675	[Tk:: => AnyEvent::Impl::Tk::],	750	[Tk:: => AnyEvent::Impl::Tk::],
676	[Wx:: => AnyEvent::Impl::POE::],	751	[Wx:: => AnyEvent::Impl::POE::],
677	[Prima:: => AnyEvent::Impl::POE::],	752	[Prima:: => AnyEvent::Impl::POE::],
…		…
681	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	756	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
682	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	757	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
683	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	758	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
684	);	759	);
685		760
686	our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY);	761	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);
		762
		763	our @post_detect;
		764
		765	sub post_detect(&) {
		766	my ($cb) = @_;
		767
		768	if ($MODEL) {
		769	$cb->();
		770
		771	1
		772	} else {
		773	push @post_detect, $cb;
		774
		775	defined wantarray
		776	? bless \$cb, "AnyEvent::Util::PostDetect"
		777	: ()
		778	}
		779	}
		780
		781	sub AnyEvent::Util::PostDetect::DESTROY {
		782	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		783	}
687		784
688	sub detect() {	785	sub detect() {
689	unless ($MODEL) {	786	unless ($MODEL) {
690	no strict 'refs';	787	no strict 'refs';
691		788
…		…
725	last;	822	last;
726	}	823	}
727	}	824	}
728		825
729	$MODEL	826	$MODEL
730	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.";	827	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
731	}	828	}
732	}	829	}
733		830
734	unshift @ISA, $MODEL;	831	unshift @ISA, $MODEL;
735	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	832	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		833
		834	(shift @post_detect)->() while @post_detect;
736	}	835	}
737		836
738	$MODEL	837	$MODEL
739	}	838	}
740		839
…		…
750	$class->$func (@_);	849	$class->$func (@_);
751	}	850	}
752		851
753	package AnyEvent::Base;	852	package AnyEvent::Base;
754		853
755	# default implementation for ->condvar, ->wait, ->broadcast	854	# default implementation for ->condvar
756		855
757	sub condvar {	856	sub condvar {
758	bless \my $flag, "AnyEvent::Base::CondVar"	857	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
759	}
760
761	sub AnyEvent::Base::CondVar::broadcast {
762	${$_[0]}++;
763	}
764
765	sub AnyEvent::Base::CondVar::wait {
766	AnyEvent->one_event while !${$_[0]};
767	}	858	}
768		859
769	# default implementation for ->signal	860	# default implementation for ->signal
770		861
771	our %SIG_CB;	862	our %SIG_CB;
…		…
845	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	936	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
846		937
847	undef $CHLD_W unless keys %PID_CB;	938	undef $CHLD_W unless keys %PID_CB;
848	}	939	}
849		940
		941	package AnyEvent::CondVar;
		942
		943	our @ISA = AnyEvent::CondVar::Base::;
		944
		945	package AnyEvent::CondVar::Base;
		946
		947	use overload
		948	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		949	fallback => 1;
		950
		951	sub _send {
		952	# nop
		953	}
		954
		955	sub send {
		956	my $cv = shift;
		957	$cv->{_ae_sent} = [@_];
		958	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		959	$cv->_send;
		960	}
		961
		962	sub croak {
		963	$_[0]{_ae_croak} = $_[1];
		964	$_[0]->send;
		965	}
		966
		967	sub ready {
		968	$_[0]{_ae_sent}
		969	}
		970
		971	sub _wait {
		972	AnyEvent->one_event while !$_[0]{_ae_sent};
		973	}
		974
		975	sub recv {
		976	$_[0]->_wait;
		977
		978	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		979	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		980	}
		981
		982	sub cb {
		983	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		984	$_[0]{_ae_cb}
		985	}
		986
		987	sub begin {
		988	++$_[0]{_ae_counter};
		989	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		990	}
		991
		992	sub end {
		993	return if --$_[0]{_ae_counter};
		994	&{ $_[0]{_ae_end_cb} \|\| sub { $_[0]->send } };
		995	}
		996
		997	# undocumented/compatibility with pre-3.4
		998	*broadcast = \&send;
		999	*wait = \&_wait;
		1000
850	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1001	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
851		1002
852	This is an advanced topic that you do not normally need to use AnyEvent in	1003	This is an advanced topic that you do not normally need to use AnyEvent in
853	a module. This section is only of use to event loop authors who want to	1004	a module. This section is only of use to event loop authors who want to
854	provide AnyEvent compatibility.	1005	provide AnyEvent compatibility.
…		…
910	model it chooses.	1061	model it chooses.
911		1062
912	=item C<PERL_ANYEVENT_MODEL>	1063	=item C<PERL_ANYEVENT_MODEL>
913		1064
914	This can be used to specify the event model to be used by AnyEvent, before	1065	This can be used to specify the event model to be used by AnyEvent, before
915	autodetection and -probing kicks in. It must be a string consisting	1066	auto detection and -probing kicks in. It must be a string consisting
916	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1067	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
917	and the resulting module name is loaded and if the load was successful,	1068	and the resulting module name is loaded and if the load was successful,
918	used as event model. If it fails to load AnyEvent will proceed with	1069	used as event model. If it fails to load AnyEvent will proceed with
919	autodetection and -probing.	1070	auto detection and -probing.
920		1071
921	This functionality might change in future versions.	1072	This functionality might change in future versions.
922		1073
923	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1074	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
924	could start your program like this:	1075	could start your program like this:
925		1076
926	PERL_ANYEVENT_MODEL=Perl perl ...	1077	PERL_ANYEVENT_MODEL=Perl perl ...
		1078
		1079	=item C<PERL_ANYEVENT_PROTOCOLS>
		1080
		1081	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1082	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1083	of auto probing).
		1084
		1085	Must be set to a comma-separated list of protocols or address families,
		1086	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1087	used, and preference will be given to protocols mentioned earlier in the
		1088	list.
		1089
		1090	This variable can effectively be used for denial-of-service attacks
		1091	against local programs (e.g. when setuid), although the impact is likely
		1092	small, as the program has to handle connection errors already-
		1093
		1094	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1095	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1096	- only support IPv4, never try to resolve or contact IPv6
		1097	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1098	IPv6, but prefer IPv6 over IPv4.
		1099
		1100	=item C<PERL_ANYEVENT_EDNS0>
		1101
		1102	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1103	for DNS. This extension is generally useful to reduce DNS traffic, but
		1104	some (broken) firewalls drop such DNS packets, which is why it is off by
		1105	default.
		1106
		1107	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1108	EDNS0 in its DNS requests.
927		1109
928	=back	1110	=back
929		1111
930	=head1 EXAMPLE PROGRAM	1112	=head1 EXAMPLE PROGRAM
931		1113
…		…
942	poll => 'r',	1124	poll => 'r',
943	cb => sub {	1125	cb => sub {
944	warn "io event <$_[0]>\n"; # will always output <r>	1126	warn "io event <$_[0]>\n"; # will always output <r>
945	chomp (my $input = <STDIN>); # read a line	1127	chomp (my $input = <STDIN>); # read a line
946	warn "read: $input\n"; # output what has been read	1128	warn "read: $input\n"; # output what has been read
947	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1129	$cv->send if $input =~ /^q/i; # quit program if /^q/i
948	},	1130	},
949	);	1131	);
950		1132
951	my $time_watcher; # can only be used once	1133	my $time_watcher; # can only be used once
952		1134
…		…
957	});	1139	});
958	}	1140	}
959		1141
960	new_timer; # create first timer	1142	new_timer; # create first timer
961		1143
962	$cv->wait; # wait until user enters /^q/i	1144	$cv->recv; # wait until user enters /^q/i
963		1145
964	=head1 REAL-WORLD EXAMPLE	1146	=head1 REAL-WORLD EXAMPLE
965		1147
966	Consider the L<Net::FCP> module. It features (among others) the following	1148	Consider the L<Net::FCP> module. It features (among others) the following
967	API calls, which are to freenet what HTTP GET requests are to http:	1149	API calls, which are to freenet what HTTP GET requests are to http:
…		…
1017	syswrite $txn->{fh}, $txn->{request}	1199	syswrite $txn->{fh}, $txn->{request}
1018	or die "connection or write error";	1200	or die "connection or write error";
1019	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1201	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1020		1202
1021	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1203	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
1022	result and signals any possible waiters that the request ahs finished:	1204	result and signals any possible waiters that the request has finished:
1023		1205
1024	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1206	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1025		1207
1026	if (end-of-file or data complete) {	1208	if (end-of-file or data complete) {
1027	$txn->{result} = $txn->{buf};	1209	$txn->{result} = $txn->{buf};
1028	$txn->{finished}->broadcast;	1210	$txn->{finished}->send;
1029	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1211	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
1030	}	1212	}
1031		1213
1032	The C<result> method, finally, just waits for the finished signal (if the	1214	The C<result> method, finally, just waits for the finished signal (if the
1033	request was already finished, it doesn't wait, of course, and returns the	1215	request was already finished, it doesn't wait, of course, and returns the
1034	data:	1216	data:
1035		1217
1036	$txn->{finished}->wait;	1218	$txn->{finished}->recv;
1037	return $txn->{result};	1219	return $txn->{result};
1038		1220
1039	The actual code goes further and collects all errors (C<die>s, exceptions)	1221	The actual code goes further and collects all errors (C<die>s, exceptions)
1040	that occured during request processing. The C<result> method detects	1222	that occurred during request processing. The C<result> method detects
1041	whether an exception as thrown (it is stored inside the $txn object)	1223	whether an exception as thrown (it is stored inside the $txn object)
1042	and just throws the exception, which means connection errors and other	1224	and just throws the exception, which means connection errors and other
1043	problems get reported tot he code that tries to use the result, not in a	1225	problems get reported tot he code that tries to use the result, not in a
1044	random callback.	1226	random callback.
1045		1227
…		…
1076		1258
1077	my $quit = AnyEvent->condvar;	1259	my $quit = AnyEvent->condvar;
1078		1260
1079	$fcp->txn_client_get ($url)->cb (sub {	1261	$fcp->txn_client_get ($url)->cb (sub {
1080	...	1262	...
1081	$quit->broadcast;	1263	$quit->send;
1082	});	1264	});
1083		1265
1084	$quit->wait;	1266	$quit->recv;
1085		1267
1086		1268
1087	=head1 BENCHMARKS	1269	=head1 BENCHMARKS
1088		1270
1089	To give you an idea of the performance and overheads that AnyEvent adds	1271	To give you an idea of the performance and overheads that AnyEvent adds
…		…
1091	of various event loops I prepared some benchmarks.	1273	of various event loops I prepared some benchmarks.
1092		1274
1093	=head2 BENCHMARKING ANYEVENT OVERHEAD	1275	=head2 BENCHMARKING ANYEVENT OVERHEAD
1094		1276
1095	Here is a benchmark of various supported event models used natively and	1277	Here is a benchmark of various supported event models used natively and
1096	through anyevent. The benchmark creates a lot of timers (with a zero	1278	through AnyEvent. The benchmark creates a lot of timers (with a zero
1097	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	1279	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1098	which it is), lets them fire exactly once and destroys them again.	1280	which it is), lets them fire exactly once and destroys them again.
1099		1281
1100	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1282	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1101	distribution.	1283	distribution.
…		…
1118	all watchers, to avoid adding memory overhead. That means closure creation	1300	all watchers, to avoid adding memory overhead. That means closure creation
1119	and memory usage is not included in the figures.	1301	and memory usage is not included in the figures.
1120		1302
1121	I<invoke> is the time, in microseconds, used to invoke a simple	1303	I<invoke> is the time, in microseconds, used to invoke a simple
1122	callback. The callback simply counts down a Perl variable and after it was	1304	callback. The callback simply counts down a Perl variable and after it was
1123	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1305	invoked "watcher" times, it would C<< ->send >> a condvar once to
1124	signal the end of this phase.	1306	signal the end of this phase.
1125		1307
1126	I<destroy> is the time, in microseconds, that it takes to destroy a single	1308	I<destroy> is the time, in microseconds, that it takes to destroy a single
1127	watcher.	1309	watcher.
1128		1310
…		…
1224		1406
1225	=back	1407	=back
1226		1408
1227	=head2 BENCHMARKING THE LARGE SERVER CASE	1409	=head2 BENCHMARKING THE LARGE SERVER CASE
1228		1410
1229	This benchmark atcually benchmarks the event loop itself. It works by	1411	This benchmark actually benchmarks the event loop itself. It works by
1230	creating a number of "servers": each server consists of a socketpair, a	1412	creating a number of "servers": each server consists of a socket pair, a
1231	timeout watcher that gets reset on activity (but never fires), and an I/O	1413	timeout watcher that gets reset on activity (but never fires), and an I/O
1232	watcher waiting for input on one side of the socket. Each time the socket	1414	watcher waiting for input on one side of the socket. Each time the socket
1233	watcher reads a byte it will write that byte to a random other "server".	1415	watcher reads a byte it will write that byte to a random other "server".
1234		1416
1235	The effect is that there will be a lot of I/O watchers, only part of which	1417	The effect is that there will be a lot of I/O watchers, only part of which
1236	are active at any one point (so there is a constant number of active	1418	are active at any one point (so there is a constant number of active
1237	fds for each loop iterstaion, but which fds these are is random). The	1419	fds for each loop iteration, but which fds these are is random). The
1238	timeout is reset each time something is read because that reflects how	1420	timeout is reset each time something is read because that reflects how
1239	most timeouts work (and puts extra pressure on the event loops).	1421	most timeouts work (and puts extra pressure on the event loops).
1240		1422
1241	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1423	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1242	(1%) are active. This mirrors the activity of large servers with many	1424	(1%) are active. This mirrors the activity of large servers with many
1243	connections, most of which are idle at any one point in time.	1425	connections, most of which are idle at any one point in time.
1244		1426
1245	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1427	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1246	distribution.	1428	distribution.
…		…
1248	=head3 Explanation of the columns	1430	=head3 Explanation of the columns
1249		1431
1250	I<sockets> is the number of sockets, and twice the number of "servers" (as	1432	I<sockets> is the number of sockets, and twice the number of "servers" (as
1251	each server has a read and write socket end).	1433	each server has a read and write socket end).
1252		1434
1253	I<create> is the time it takes to create a socketpair (which is	1435	I<create> is the time it takes to create a socket pair (which is
1254	nontrivial) and two watchers: an I/O watcher and a timeout watcher.	1436	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1255		1437
1256	I<request>, the most important value, is the time it takes to handle a	1438	I<request>, the most important value, is the time it takes to handle a
1257	single "request", that is, reading the token from the pipe and forwarding	1439	single "request", that is, reading the token from the pipe and forwarding
1258	it to another server. This includes deleting the old timeout and creating	1440	it to another server. This includes deleting the old timeout and creating
…		…
1331	speed most when you have lots of watchers, not when you only have a few of	1513	speed most when you have lots of watchers, not when you only have a few of
1332	them).	1514	them).
1333		1515
1334	EV is again fastest.	1516	EV is again fastest.
1335		1517
1336	Perl again comes second. It is noticably faster than the C-based event	1518	Perl again comes second. It is noticeably faster than the C-based event
1337	loops Event and Glib, although the difference is too small to really	1519	loops Event and Glib, although the difference is too small to really
1338	matter.	1520	matter.
1339		1521
1340	POE also performs much better in this case, but is is still far behind the	1522	POE also performs much better in this case, but is is still far behind the
1341	others.	1523	others.
…		…
1374		1556
1375	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1557	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1376		1558
1377	use AnyEvent;	1559	use AnyEvent;
1378		1560
		1561	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
		1562	be used to probe what backend is used and gain other information (which is
		1563	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
		1564
1379		1565
1380	=head1 SEE ALSO	1566	=head1 SEE ALSO
1381		1567
1382	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,	1568	Utility functions: L<AnyEvent::Util>.
1383	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,	1569
		1570	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1384	L<Event::Lib>, L<Qt>, L<POE>.	1571	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1385		1572
1386	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,	1573	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1387	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,	1574	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1388	L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>,	1575	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1389	L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>.	1576	L<AnyEvent::Impl::POE>.
1390		1577
		1578	Non-blocking file handles, sockets, TCP clients and
		1579	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1580
		1581	Asynchronous DNS: L<AnyEvent::DNS>.
		1582
		1583	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
		1584
1391	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1585	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1392		1586
1393		1587
1394	=head1 AUTHOR	1588	=head1 AUTHOR
1395		1589
1396	Marc Lehmann <schmorp@schmorp.de>	1590	Marc Lehmann <schmorp@schmorp.de>

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.105 by root, Thu May 1 12:35:54 2008 UTC vs. Revision 1.134 by root, Sun May 25 04:44:04 2008 UTC

Diff Legend

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.105 by root, Thu May 1 12:35:54 2008 UTC vs.
Revision 1.134 by root, Sun May 25 04:44:04 2008 UTC