[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 1.140 by root, Mon May 26 06:18:53 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, read about the caveats in the description for the C<<
		318	->send >> method).
319		319
320	Condition variables are similar to callbacks, except that you can	320	Condition variables are similar to callbacks, except that you can
321	optionally wait for them. They can also be called merge points - points	321	optionally wait for them. They can also be called merge points - points
322	in time where multiple outstandign events have been processed. And yet	322	in time where multiple outstanding events have been processed. And yet
323	another way to call them is transations - each condition variable can be	323	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	324	used to represent a transaction, which finishes at some point and delivers
325	a result.	325	a result.
326		326
327	Condition variables are very useful to signal that something has finished,	327	Condition variables are very useful to signal that something has finished,
328	for example, if you write a module that does asynchronous http requests,	328	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	329	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	330	availability of results. The user can either act when the callback is
331	called or can synchronously C<< ->wait >> for the results.	331	called or can synchronously C<< ->recv >> for the results.
332		332
333	You can also use them to simulate traditional event loops - for example,	333	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	334	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	335	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.	336	button of your app, which would C<< ->send >> the "quit" event.
337		337
338	Note that condition variables recurse into the event loop - if you have	338	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	339	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	340	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,	341	you should avoid making a blocking wait yourself, at least in callbacks,
342	as this asks for trouble.	342	as this asks for trouble.
343		343
344	Condition variables are represented by hash refs in perl, and the keys	344	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	346	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	347	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
348	it's C<new> method in your own C<new> method.	348	it's C<new> method in your own C<new> method.
349		349
350	There are two "sides" to a condition variable - the "producer side" which	350	There are two "sides" to a condition variable - the "producer side" which
351	eventually calls C<< -> broadcast >>, and the "consumer side", which waits	351	eventually calls C<< -> send >>, and the "consumer side", which waits
352	for the broadcast to occur.	352	for the send to occur.
353		353
354	Example:	354	Example: wait for a timer.
355		355
356	# wait till the result is ready	356	# wait till the result is ready
357	my $result_ready = AnyEvent->condvar;	357	my $result_ready = AnyEvent->condvar;
358		358
359	# do something such as adding a timer	359	# do something such as adding a timer
360	# or socket watcher the calls $result_ready->broadcast	360	# or socket watcher the calls $result_ready->send
361	# when the "result" is ready.	361	# when the "result" is ready.
362	# in this case, we simply use a timer:	362	# in this case, we simply use a timer:
363	my $w = AnyEvent->timer (	363	my $w = AnyEvent->timer (
364	after => 1,	364	after => 1,
365	cb => sub { $result_ready->broadcast },	365	cb => sub { $result_ready->send },
366	);	366	);
367		367
368	# this "blocks" (while handling events) till the callback	368	# this "blocks" (while handling events) till the callback
369	# calls broadcast	369	# calls send
370	$result_ready->wait;	370	$result_ready->recv;
		371
		372	Example: wait for a timer, but take advantage of the fact that
		373	condition variables are also code references.
		374
		375	my $done = AnyEvent->condvar;
		376	my $delay = AnyEvent->timer (after => 5, cb => $done);
		377	$done->recv;
371		378
372	=head3 METHODS FOR PRODUCERS	379	=head3 METHODS FOR PRODUCERS
373		380
374	These methods should only be used by the producing side, i.e. the	381	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	382	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	383	the producer side which creates the condvar in most cases, but it isn't
377	uncommon for the consumer to create it as well.	384	uncommon for the consumer to create it as well.
378		385
379	=over 4	386	=over 4
380		387
381	=item $cv->broadcast (...)	388	=item $cv->send (...)
382		389
383	Flag the condition as ready - a running C<< ->wait >> and all further	390	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	391	calls to C<recv> will (eventually) return after this method has been
385	called. If nobody is waiting the broadcast will be remembered.	392	called. If nobody is waiting the send will be remembered.
386		393
387	If a callback has been set on the condition variable, it is called	394	If a callback has been set on the condition variable, it is called
388	immediately from within broadcast.	395	immediately from within send.
389		396
390	Any arguments passed to the C<broadcast> call will be returned by all	397	Any arguments passed to the C<send> call will be returned by all
391	future C<< ->wait >> calls.	398	future C<< ->recv >> calls.
		399
		400	Condition variables are overloaded so one can call them directly
		401	(as a code reference). Calling them directly is the same as calling
		402	C<send>. Note, however, that many C-based event loops do not handle
		403	overloading, so as tempting as it may be, passing a condition variable
		404	instead of a callback does not work. Both the pure perl and EV loops
		405	support overloading, however, as well as all functions that use perl to
		406	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
		407	example).
392		408
393	=item $cv->croak ($error)	409	=item $cv->croak ($error)
394		410
395	Similar to broadcast, but causes all call's wait C<< ->wait >> to invoke	411	Similar to send, but causes all call's to C<< ->recv >> to invoke
396	C<Carp::croak> with the given error message/object/scalar.	412	C<Carp::croak> with the given error message/object/scalar.
397		413
398	This can be used to signal any errors to the condition variable	414	This can be used to signal any errors to the condition variable
399	user/consumer.	415	user/consumer.
400		416
401	=item $cv->begin ([group callback])	417	=item $cv->begin ([group callback])
402		418
403	=item $cv->end	419	=item $cv->end
		420
		421	These two methods are EXPERIMENTAL and MIGHT CHANGE.
404		422
405	These two methods can be used to combine many transactions/events into	423	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	424	one. For example, a function that pings many hosts in parallel might want
407	to use a condition variable for the whole process.	425	to use a condition variable for the whole process.
408		426
409	Every call to C<< ->begin >> will increment a counter, and every call to	427	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	428	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	429	>>, 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	430	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.	431	callback was set, C<send> will be called without any arguments.
414		432
415	Let's clarify this with the ping example:	433	Let's clarify this with the ping example:
416		434
417	my $cv = AnyEvent->condvar;	435	my $cv = AnyEvent->condvar;
418		436
419	my %result;	437	my %result;
420	$cv->begin (sub { $cv->broadcast (\%result) });	438	$cv->begin (sub { $cv->send (\%result) });
421		439
422	for my $host (@list_of_hosts) {	440	for my $host (@list_of_hosts) {
423	$cv->begin;	441	$cv->begin;
424	ping_host_then_call_callback $host, sub {	442	ping_host_then_call_callback $host, sub {
425	$result{$host} = ...;	443	$result{$host} = ...;
…		…
428	}	446	}
429		447
430	$cv->end;	448	$cv->end;
431		449
432	This code fragment supposedly pings a number of hosts and calls	450	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	451	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	452	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	453	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	454	it. Since C<begin> and C<end> only maintain a counter, the order in which
437	results arrive is not relevant.	455	results arrive is not relevant.
438		456
439	There is an additional bracketing call to C<begin> and C<end> outside the	457	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	458	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	459	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	460	C<send> is called even when C<no> hosts are being pinged (the loop
443	doesn't execute once).	461	doesn't execute once).
444		462
445	This is the general pattern when you "fan out" into multiple subrequests:	463	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>	464	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	465	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>.	466	C<begin> and for each subrequest you finish, call C<end>.
449		467
450	=back	468	=back
451		469
452	=head3 METHODS FOR CONSUMERS	470	=head3 METHODS FOR CONSUMERS
453		471
454	These methods should only be used by the consuming side, i.e. the	472	These methods should only be used by the consuming side, i.e. the
455	code awaits the condition.	473	code awaits the condition.
456		474
457	=item $cv->wait	475	=over 4
458		476
		477	=item $cv->recv
		478
459	Wait (blocking if necessary) until the C<< ->broadcast >> or C<< ->croak	479	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
460	>> methods have been called on c<$cv>, while servicing other watchers	480	>> methods have been called on c<$cv>, while servicing other watchers
461	normally.	481	normally.
462		482
463	You can only wait once on a condition - additional calls are valid but	483	You can only wait once on a condition - additional calls are valid but
464	will return immediately.	484	will return immediately.
465		485
466	If an error condition has been set by calling C<< ->croak >>, then this	486	If an error condition has been set by calling C<< ->croak >>, then this
467	function will call C<croak>.	487	function will call C<croak>.
468		488
469	In list context, all parameters passed to C<broadcast> will be returned,	489	In list context, all parameters passed to C<send> will be returned,
470	in scalar context only the first one will be returned.	490	in scalar context only the first one will be returned.
471		491
472	Not all event models support a blocking wait - some die in that case	492	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	493	(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	494	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	495	caller decide whether the call will block or not (for example, by coupling
476	condition variables with some kind of request results and supporting	496	condition variables with some kind of request results and supporting
477	callbacks so the caller knows that getting the result will not block,	497	callbacks so the caller knows that getting the result will not block,
478	while still suppporting blocking waits if the caller so desires).	498	while still supporting blocking waits if the caller so desires).
479		499
480	Another reason I<never> to C<< ->wait >> in a module is that you cannot	500	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	501	sensibly have two C<< ->recv >>'s in parallel, as that would require
482	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	502	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
483	can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and	503	can supply.
484	L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
485	from different coroutines, however).
486		504
		505	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
		506	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
		507	versions and also integrates coroutines into AnyEvent, making blocking
		508	C<< ->recv >> calls perfectly safe as long as they are done from another
		509	coroutine (one that doesn't run the event loop).
		510
487	You can ensure that C<< -wait >> never blocks by setting a callback and	511	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	512	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	513	time). This will work even when the event loop does not support blocking
490	waits otherwise.	514	waits otherwise.
		515
		516	=item $bool = $cv->ready
		517
		518	Returns true when the condition is "true", i.e. whether C<send> or
		519	C<croak> have been called.
		520
		521	=item $cb = $cv->cb ([new callback])
		522
		523	This is a mutator function that returns the callback set and optionally
		524	replaces it before doing so.
		525
		526	The callback will be called when the condition becomes "true", i.e. when
		527	C<send> or C<croak> are called. Calling C<recv> inside the callback
		528	or at any later time is guaranteed not to block.
491		529
492	=back	530	=back
493		531
494	=head1 GLOBAL VARIABLES AND FUNCTIONS	532	=head1 GLOBAL VARIABLES AND FUNCTIONS
495		533
…		…
503	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	541	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
504	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	542	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
505		543
506	The known classes so far are:	544	The known classes so far are:
507		545
508	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
509	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
510	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).	546	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
511	AnyEvent::Impl::Event based on Event, second best choice.	547	AnyEvent::Impl::Event based on Event, second best choice.
512	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	548	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
513	AnyEvent::Impl::Glib based on Glib, third-best choice.	549	AnyEvent::Impl::Glib based on Glib, third-best choice.
514	AnyEvent::Impl::Tk based on Tk, very bad choice.	550	AnyEvent::Impl::Tk based on Tk, very bad choice.
…		…
531	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	567	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
532	if necessary. You should only call this function right before you would	568	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	569	have created an AnyEvent watcher anyway, that is, as late as possible at
534	runtime.	570	runtime.
535		571
		572	=item $guard = AnyEvent::post_detect { BLOCK }
		573
		574	Arranges for the code block to be executed as soon as the event model is
		575	autodetected (or immediately if this has already happened).
		576
		577	If called in scalar or list context, then it creates and returns an object
		578	that automatically removes the callback again when it is destroyed. See
		579	L<Coro::BDB> for a case where this is useful.
		580
		581	=item @AnyEvent::post_detect
		582
		583	If there are any code references in this array (you can C<push> to it
		584	before or after loading AnyEvent), then they will called directly after
		585	the event loop has been chosen.
		586
		587	You should check C<$AnyEvent::MODEL> before adding to this array, though:
		588	if it contains a true value then the event loop has already been detected,
		589	and the array will be ignored.
		590
		591	Best use C<AnyEvent::post_detect { BLOCK }> instead.
		592
536	=back	593	=back
537		594
538	=head1 WHAT TO DO IN A MODULE	595	=head1 WHAT TO DO IN A MODULE
539		596
540	As a module author, you should C<use AnyEvent> and call AnyEvent methods	597	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	600	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	601	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	602	by calling AnyEvent in your module body you force the user of your module
546	to load the event module first.	603	to load the event module first.
547		604
548	Never call C<< ->wait >> on a condition variable unless you I<know> that	605	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	606	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	607	because it will stall the whole program, and the whole point of using
551	events is to stay interactive.	608	events is to stay interactive.
552		609
553	It is fine, however, to call C<< ->wait >> when the user of your module	610	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	611	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 >>	612	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).	613	freely, as the user of your module knows what she is doing. always).
557		614
558	=head1 WHAT TO DO IN THE MAIN PROGRAM	615	=head1 WHAT TO DO IN THE MAIN PROGRAM
559		616
560	There will always be a single main program - the only place that should	617	There will always be a single main program - the only place that should
…		…
562		619
563	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	620	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	621	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.	622	decide which implementation to chose if some module relies on it.
566		623
567	If the main program relies on a specific event model. For example, in	624	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	625	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	626	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	627	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	628	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	629	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.	630	might chose the wrong one unless you load the correct one yourself.
574		631
575	You can chose to use a rather inefficient pure-perl implementation by	632	You can chose to use a pure-perl implementation by loading the
576	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	633	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
577	behaviour everywhere, but letting AnyEvent chose is generally better.	634	everywhere, but letting AnyEvent chose the model is generally better.
		635
		636	=head2 MAINLOOP EMULATION
		637
		638	Sometimes (often for short test scripts, or even standalone programs who
		639	only want to use AnyEvent), you do not want to run a specific event loop.
		640
		641	In that case, you can use a condition variable like this:
		642
		643	AnyEvent->condvar->recv;
		644
		645	This has the effect of entering the event loop and looping forever.
		646
		647	Note that usually your program has some exit condition, in which case
		648	it is better to use the "traditional" approach of storing a condition
		649	variable somewhere, waiting for it, and sending it when the program should
		650	exit cleanly.
		651
578		652
579	=head1 OTHER MODULES	653	=head1 OTHER MODULES
580		654
581	The following is a non-exhaustive list of additional modules that use	655	The following is a non-exhaustive list of additional modules that use
582	AnyEvent and can therefore be mixed easily with other AnyEvent modules	656	AnyEvent and can therefore be mixed easily with other AnyEvent modules
…		…
594		668
595	Provide read and write buffers and manages watchers for reads and writes.	669	Provide read and write buffers and manages watchers for reads and writes.
596		670
597	=item L<AnyEvent::Socket>	671	=item L<AnyEvent::Socket>
598		672
599	Provides a means to do non-blocking connects, accepts etc.	673	Provides various utility functions for (internet protocol) sockets,
		674	addresses and name resolution. Also functions to create non-blocking tcp
		675	connections or tcp servers, with IPv6 and SRV record support and more.
		676
		677	=item L<AnyEvent::DNS>
		678
		679	Provides rich asynchronous DNS resolver capabilities.
600		680
601	=item L<AnyEvent::HTTPD>	681	=item L<AnyEvent::HTTPD>
602		682
603	Provides a simple web application server framework.	683	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		684
610	=item L<AnyEvent::FastPing>	685	=item L<AnyEvent::FastPing>
611		686
612	The fastest ping in the west.	687	The fastest ping in the west.
613		688
…		…
628		703
629	High level API for event-based execution flow control.	704	High level API for event-based execution flow control.
630		705
631	=item L<Coro>	706	=item L<Coro>
632		707
633	Has special support for AnyEvent.	708	Has special support for AnyEvent via L<Coro::AnyEvent>.
		709
		710	=item L<AnyEvent::AIO>, L<IO::AIO>
		711
		712	Truly asynchronous I/O, should be in the toolbox of every event
		713	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
		714	together.
		715
		716	=item L<AnyEvent::BDB>, L<BDB>
		717
		718	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
		719	IO::AIO and AnyEvent together.
634		720
635	=item L<IO::Lambda>	721	=item L<IO::Lambda>
636		722
637	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	723	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		724
649	=back	725	=back
650		726
651	=cut	727	=cut
652		728
…		…
655	no warnings;	731	no warnings;
656	use strict;	732	use strict;
657		733
658	use Carp;	734	use Carp;
659		735
660	our $VERSION = '3.3';	736	our $VERSION = '4.04';
661	our $MODEL;	737	our $MODEL;
662		738
663	our $AUTOLOAD;	739	our $AUTOLOAD;
664	our @ISA;	740	our @ISA;
665		741
		742	our @REGISTRY;
		743
		744	our $WIN32;
		745
		746	BEGIN {
		747	my $win32 = ! ! ($^O =~ /mswin32/i);
		748	eval "sub WIN32(){ $win32 }";
		749	}
		750
666	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	751	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
667		752
668	our @REGISTRY;	753	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
		754
		755	{
		756	my $idx;
		757	$PROTOCOL{$_} = ++$idx
		758	for reverse split /\s,\s/,
		759	$ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
		760	}
669		761
670	my @models = (	762	my @models = (
671	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
672	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
673	[EV:: => AnyEvent::Impl::EV::],	763	[EV:: => AnyEvent::Impl::EV::],
674	[Event:: => AnyEvent::Impl::Event::],	764	[Event:: => AnyEvent::Impl::Event::],
675	[Tk:: => AnyEvent::Impl::Tk::],
676	[Wx:: => AnyEvent::Impl::POE::],
677	[Prima:: => AnyEvent::Impl::POE::],
678	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	765	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
679	# everything below here will not be autoprobed as the pureperl backend should work everywhere	766	# everything below here will not be autoprobed
680	[Glib:: => AnyEvent::Impl::Glib::],	767	# as the pureperl backend should work everywhere
		768	# and is usually faster
		769	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		770	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
681	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	771	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
682	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	772	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
683	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	773	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
		774	[Wx:: => AnyEvent::Impl::POE::],
		775	[Prima:: => AnyEvent::Impl::POE::],
684	);	776	);
685		777
686	our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY);	778	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);
		779
		780	our @post_detect;
		781
		782	sub post_detect(&) {
		783	my ($cb) = @_;
		784
		785	if ($MODEL) {
		786	$cb->();
		787
		788	1
		789	} else {
		790	push @post_detect, $cb;
		791
		792	defined wantarray
		793	? bless \$cb, "AnyEvent::Util::PostDetect"
		794	: ()
		795	}
		796	}
		797
		798	sub AnyEvent::Util::PostDetect::DESTROY {
		799	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		800	}
687		801
688	sub detect() {	802	sub detect() {
689	unless ($MODEL) {	803	unless ($MODEL) {
690	no strict 'refs';	804	no strict 'refs';
		805	local $SIG{__DIE__};
691		806
692	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	807	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
693	my $model = "AnyEvent::Impl::$1";	808	my $model = "AnyEvent::Impl::$1";
694	if (eval "require $model") {	809	if (eval "require $model") {
695	$MODEL = $model;	810	$MODEL = $model;
…		…
725	last;	840	last;
726	}	841	}
727	}	842	}
728		843
729	$MODEL	844	$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.";	845	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
731	}	846	}
732	}	847	}
733		848
734	unshift @ISA, $MODEL;	849	unshift @ISA, $MODEL;
735	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	850	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		851
		852	(shift @post_detect)->() while @post_detect;
736	}	853	}
737		854
738	$MODEL	855	$MODEL
739	}	856	}
740		857
…		…
750	$class->$func (@_);	867	$class->$func (@_);
751	}	868	}
752		869
753	package AnyEvent::Base;	870	package AnyEvent::Base;
754		871
755	# default implementation for ->condvar, ->wait, ->broadcast	872	# default implementation for ->condvar
756		873
757	sub condvar {	874	sub condvar {
758	bless \my $flag, "AnyEvent::Base::CondVar"	875	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	}	876	}
768		877
769	# default implementation for ->signal	878	# default implementation for ->signal
770		879
771	our %SIG_CB;	880	our %SIG_CB;
…		…
824	or Carp::croak "required option 'pid' is missing";	933	or Carp::croak "required option 'pid' is missing";
825		934
826	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	935	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
827		936
828	unless ($WNOHANG) {	937	unless ($WNOHANG) {
829	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } \|\| 1;	938	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
830	}	939	}
831		940
832	unless ($CHLD_W) {	941	unless ($CHLD_W) {
833	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	942	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
834	# child could be a zombie already, so make at least one round	943	# child could be a zombie already, so make at least one round
…		…
844	delete $PID_CB{$pid}{$cb};	953	delete $PID_CB{$pid}{$cb};
845	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	954	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
846		955
847	undef $CHLD_W unless keys %PID_CB;	956	undef $CHLD_W unless keys %PID_CB;
848	}	957	}
		958
		959	package AnyEvent::CondVar;
		960
		961	our @ISA = AnyEvent::CondVar::Base::;
		962
		963	package AnyEvent::CondVar::Base;
		964
		965	use overload
		966	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		967	fallback => 1;
		968
		969	sub _send {
		970	# nop
		971	}
		972
		973	sub send {
		974	my $cv = shift;
		975	$cv->{_ae_sent} = [@_];
		976	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		977	$cv->_send;
		978	}
		979
		980	sub croak {
		981	$_[0]{_ae_croak} = $_[1];
		982	$_[0]->send;
		983	}
		984
		985	sub ready {
		986	$_[0]{_ae_sent}
		987	}
		988
		989	sub _wait {
		990	AnyEvent->one_event while !$_[0]{_ae_sent};
		991	}
		992
		993	sub recv {
		994	$_[0]->_wait;
		995
		996	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		997	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		998	}
		999
		1000	sub cb {
		1001	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		1002	$_[0]{_ae_cb}
		1003	}
		1004
		1005	sub begin {
		1006	++$_[0]{_ae_counter};
		1007	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		1008	}
		1009
		1010	sub end {
		1011	return if --$_[0]{_ae_counter};
		1012	&{ $_[0]{_ae_end_cb} \|\| sub { $_[0]->send } };
		1013	}
		1014
		1015	# undocumented/compatibility with pre-3.4
		1016	*broadcast = \&send;
		1017	*wait = \&_wait;
849		1018
850	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1019	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
851		1020
852	This is an advanced topic that you do not normally need to use AnyEvent in	1021	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	1022	a module. This section is only of use to event loop authors who want to
…		…
910	model it chooses.	1079	model it chooses.
911		1080
912	=item C<PERL_ANYEVENT_MODEL>	1081	=item C<PERL_ANYEVENT_MODEL>
913		1082
914	This can be used to specify the event model to be used by AnyEvent, before	1083	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	1084	auto detection and -probing kicks in. It must be a string consisting
916	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1085	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,	1086	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	1087	used as event model. If it fails to load AnyEvent will proceed with
919	autodetection and -probing.	1088	auto detection and -probing.
920		1089
921	This functionality might change in future versions.	1090	This functionality might change in future versions.
922		1091
923	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1092	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
924	could start your program like this:	1093	could start your program like this:
925		1094
926	PERL_ANYEVENT_MODEL=Perl perl ...	1095	PERL_ANYEVENT_MODEL=Perl perl ...
		1096
		1097	=item C<PERL_ANYEVENT_PROTOCOLS>
		1098
		1099	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1100	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1101	of auto probing).
		1102
		1103	Must be set to a comma-separated list of protocols or address families,
		1104	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1105	used, and preference will be given to protocols mentioned earlier in the
		1106	list.
		1107
		1108	This variable can effectively be used for denial-of-service attacks
		1109	against local programs (e.g. when setuid), although the impact is likely
		1110	small, as the program has to handle connection errors already-
		1111
		1112	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1113	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1114	- only support IPv4, never try to resolve or contact IPv6
		1115	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1116	IPv6, but prefer IPv6 over IPv4.
		1117
		1118	=item C<PERL_ANYEVENT_EDNS0>
		1119
		1120	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1121	for DNS. This extension is generally useful to reduce DNS traffic, but
		1122	some (broken) firewalls drop such DNS packets, which is why it is off by
		1123	default.
		1124
		1125	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1126	EDNS0 in its DNS requests.
927		1127
928	=back	1128	=back
929		1129
930	=head1 EXAMPLE PROGRAM	1130	=head1 EXAMPLE PROGRAM
931		1131
…		…
942	poll => 'r',	1142	poll => 'r',
943	cb => sub {	1143	cb => sub {
944	warn "io event <$_[0]>\n"; # will always output <r>	1144	warn "io event <$_[0]>\n"; # will always output <r>
945	chomp (my $input = <STDIN>); # read a line	1145	chomp (my $input = <STDIN>); # read a line
946	warn "read: $input\n"; # output what has been read	1146	warn "read: $input\n"; # output what has been read
947	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1147	$cv->send if $input =~ /^q/i; # quit program if /^q/i
948	},	1148	},
949	);	1149	);
950		1150
951	my $time_watcher; # can only be used once	1151	my $time_watcher; # can only be used once
952		1152
…		…
957	});	1157	});
958	}	1158	}
959		1159
960	new_timer; # create first timer	1160	new_timer; # create first timer
961		1161
962	$cv->wait; # wait until user enters /^q/i	1162	$cv->recv; # wait until user enters /^q/i
963		1163
964	=head1 REAL-WORLD EXAMPLE	1164	=head1 REAL-WORLD EXAMPLE
965		1165
966	Consider the L<Net::FCP> module. It features (among others) the following	1166	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:	1167	API calls, which are to freenet what HTTP GET requests are to http:
…		…
1017	syswrite $txn->{fh}, $txn->{request}	1217	syswrite $txn->{fh}, $txn->{request}
1018	or die "connection or write error";	1218	or die "connection or write error";
1019	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1219	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1020		1220
1021	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1221	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:	1222	result and signals any possible waiters that the request has finished:
1023		1223
1024	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1224	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1025		1225
1026	if (end-of-file or data complete) {	1226	if (end-of-file or data complete) {
1027	$txn->{result} = $txn->{buf};	1227	$txn->{result} = $txn->{buf};
1028	$txn->{finished}->broadcast;	1228	$txn->{finished}->send;
1029	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1229	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
1030	}	1230	}
1031		1231
1032	The C<result> method, finally, just waits for the finished signal (if the	1232	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	1233	request was already finished, it doesn't wait, of course, and returns the
1034	data:	1234	data:
1035		1235
1036	$txn->{finished}->wait;	1236	$txn->{finished}->recv;
1037	return $txn->{result};	1237	return $txn->{result};
1038		1238
1039	The actual code goes further and collects all errors (C<die>s, exceptions)	1239	The actual code goes further and collects all errors (C<die>s, exceptions)
1040	that occured during request processing. The C<result> method detects	1240	that occurred during request processing. The C<result> method detects
1041	whether an exception as thrown (it is stored inside the $txn object)	1241	whether an exception as thrown (it is stored inside the $txn object)
1042	and just throws the exception, which means connection errors and other	1242	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	1243	problems get reported tot he code that tries to use the result, not in a
1044	random callback.	1244	random callback.
1045		1245
…		…
1076		1276
1077	my $quit = AnyEvent->condvar;	1277	my $quit = AnyEvent->condvar;
1078		1278
1079	$fcp->txn_client_get ($url)->cb (sub {	1279	$fcp->txn_client_get ($url)->cb (sub {
1080	...	1280	...
1081	$quit->broadcast;	1281	$quit->send;
1082	});	1282	});
1083		1283
1084	$quit->wait;	1284	$quit->recv;
1085		1285
1086		1286
1087	=head1 BENCHMARKS	1287	=head1 BENCHMARKS
1088		1288
1089	To give you an idea of the performance and overheads that AnyEvent adds	1289	To give you an idea of the performance and overheads that AnyEvent adds
…		…
1091	of various event loops I prepared some benchmarks.	1291	of various event loops I prepared some benchmarks.
1092		1292
1093	=head2 BENCHMARKING ANYEVENT OVERHEAD	1293	=head2 BENCHMARKING ANYEVENT OVERHEAD
1094		1294
1095	Here is a benchmark of various supported event models used natively and	1295	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	1296	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,	1297	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.	1298	which it is), lets them fire exactly once and destroys them again.
1099		1299
1100	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1300	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1101	distribution.	1301	distribution.
…		…
1118	all watchers, to avoid adding memory overhead. That means closure creation	1318	all watchers, to avoid adding memory overhead. That means closure creation
1119	and memory usage is not included in the figures.	1319	and memory usage is not included in the figures.
1120		1320
1121	I<invoke> is the time, in microseconds, used to invoke a simple	1321	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	1322	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	1323	invoked "watcher" times, it would C<< ->send >> a condvar once to
1124	signal the end of this phase.	1324	signal the end of this phase.
1125		1325
1126	I<destroy> is the time, in microseconds, that it takes to destroy a single	1326	I<destroy> is the time, in microseconds, that it takes to destroy a single
1127	watcher.	1327	watcher.
1128		1328
…		…
1224		1424
1225	=back	1425	=back
1226		1426
1227	=head2 BENCHMARKING THE LARGE SERVER CASE	1427	=head2 BENCHMARKING THE LARGE SERVER CASE
1228		1428
1229	This benchmark atcually benchmarks the event loop itself. It works by	1429	This benchmark actually benchmarks the event loop itself. It works by
1230	creating a number of "servers": each server consists of a socketpair, a	1430	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	1431	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	1432	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".	1433	watcher reads a byte it will write that byte to a random other "server".
1234		1434
1235	The effect is that there will be a lot of I/O watchers, only part of which	1435	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	1436	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	1437	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	1438	timeout is reset each time something is read because that reflects how
1239	most timeouts work (and puts extra pressure on the event loops).	1439	most timeouts work (and puts extra pressure on the event loops).
1240		1440
1241	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1441	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	1442	(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.	1443	connections, most of which are idle at any one point in time.
1244		1444
1245	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1445	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1246	distribution.	1446	distribution.
…		…
1248	=head3 Explanation of the columns	1448	=head3 Explanation of the columns
1249		1449
1250	I<sockets> is the number of sockets, and twice the number of "servers" (as	1450	I<sockets> is the number of sockets, and twice the number of "servers" (as
1251	each server has a read and write socket end).	1451	each server has a read and write socket end).
1252		1452
1253	I<create> is the time it takes to create a socketpair (which is	1453	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.	1454	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1255		1455
1256	I<request>, the most important value, is the time it takes to handle a	1456	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	1457	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	1458	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	1531	speed most when you have lots of watchers, not when you only have a few of
1332	them).	1532	them).
1333		1533
1334	EV is again fastest.	1534	EV is again fastest.
1335		1535
1336	Perl again comes second. It is noticably faster than the C-based event	1536	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	1537	loops Event and Glib, although the difference is too small to really
1338	matter.	1538	matter.
1339		1539
1340	POE also performs much better in this case, but is is still far behind the	1540	POE also performs much better in this case, but is is still far behind the
1341	others.	1541	others.
…		…
1374		1574
1375	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1575	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1376		1576
1377	use AnyEvent;	1577	use AnyEvent;
1378		1578
		1579	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
		1580	be used to probe what backend is used and gain other information (which is
		1581	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
		1582
1379		1583
1380	=head1 SEE ALSO	1584	=head1 SEE ALSO
1381		1585
1382	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,	1586	Utility functions: L<AnyEvent::Util>.
1383	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,	1587
		1588	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1384	L<Event::Lib>, L<Qt>, L<POE>.	1589	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1385		1590
1386	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,	1591	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1387	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,	1592	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>,	1593	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1389	L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>.	1594	L<AnyEvent::Impl::POE>.
1390		1595
		1596	Non-blocking file handles, sockets, TCP clients and
		1597	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1598
		1599	Asynchronous DNS: L<AnyEvent::DNS>.
		1600
		1601	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
		1602
1391	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1603	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1392		1604
1393		1605
1394	=head1 AUTHOR	1606	=head1 AUTHOR
1395		1607
1396	Marc Lehmann <schmorp@schmorp.de>	1608	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.105 by root, Thu May 1 12:35:54 2008 UTC vs. Revision 1.140 by root, Mon May 26 06:18:53 2008 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.105 by root, Thu May 1 12:35:54 2008 UTC vs.
Revision 1.140 by root, Mon May 26 06:18:53 2008 UTC