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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.102 by root, Sun Apr 27 21:16:26 2008 UTC vs.
Revision 1.129 by elmex, Sat May 24 15:19:30 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
		300	If you are familiar with some event loops you will know that all of them
		301	require you to run some blocking "loop", "run" or similar function that
		302	will actively watch for new events and call your callbacks.
		303
		304	AnyEvent is different, it expects somebody else to run the event loop and
		305	will only block when necessary (usually when told by the user).
		306
		307	The instrument to do that is called a "condition variable", so called
		308	because they represent a condition that must become true.
		309
302	Condition variables can be created by calling the C<< AnyEvent->condvar >>	310	Condition variables can be created by calling the C<< AnyEvent->condvar
303	method without any arguments.	311	>> method, usually without arguments. The only argument pair allowed is
		312	C<cb>, which specifies a callback to be called when the condition variable
		313	becomes true.
304		314
305	A condition variable waits for a condition - precisely that the C<<	315	After creation, the condition variable is "false" until it becomes "true"
306	->broadcast >> method has been called.	316	by calling the C<send> method.
307		317
308	They are very useful to signal that a condition has been fulfilled, for	318	Condition variables are similar to callbacks, except that you can
		319	optionally wait for them. They can also be called merge points - points
		320	in time where multiple outstanding events have been processed. And yet
		321	another way to call them is transactions - each condition variable can be
		322	used to represent a transaction, which finishes at some point and delivers
		323	a result.
		324
		325	Condition variables are very useful to signal that something has finished,
309	example, if you write a module that does asynchronous http requests,	326	for example, if you write a module that does asynchronous http requests,
310	then a condition variable would be the ideal candidate to signal the	327	then a condition variable would be the ideal candidate to signal the
311	availability of results.	328	availability of results. The user can either act when the callback is
		329	called or can synchronously C<< ->recv >> for the results.
312		330
313	You can also use condition variables to block your main program until	331	You can also use them to simulate traditional event loops - for example,
314	an event occurs - for example, you could C<< ->wait >> in your main	332	you can block your main program until an event occurs - for example, you
315	program until the user clicks the Quit button in your app, which would C<<	333	could C<< ->recv >> in your main program until the user clicks the Quit
316	->broadcast >> the "quit" event.	334	button of your app, which would C<< ->send >> the "quit" event.
317		335
318	Note that condition variables recurse into the event loop - if you have	336	Note that condition variables recurse into the event loop - if you have
319	two pirces of code that call C<< ->wait >> in a round-robbin fashion, you	337	two pieces of code that call C<< ->recv >> in a round-robin fashion, you
320	lose. Therefore, condition variables are good to export to your caller, but	338	lose. Therefore, condition variables are good to export to your caller, but
321	you should avoid making a blocking wait yourself, at least in callbacks,	339	you should avoid making a blocking wait yourself, at least in callbacks,
322	as this asks for trouble.	340	as this asks for trouble.
323		341
324	This object has two methods:	342	Condition variables are represented by hash refs in perl, and the keys
		343	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
		344	easy (it is often useful to build your own transaction class on top of
		345	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
		346	it's C<new> method in your own C<new> method.
		347
		348	There are two "sides" to a condition variable - the "producer side" which
		349	eventually calls C<< -> send >>, and the "consumer side", which waits
		350	for the send to occur.
		351
		352	Example:
		353
		354	# wait till the result is ready
		355	my $result_ready = AnyEvent->condvar;
		356
		357	# do something such as adding a timer
		358	# or socket watcher the calls $result_ready->send
		359	# when the "result" is ready.
		360	# in this case, we simply use a timer:
		361	my $w = AnyEvent->timer (
		362	after => 1,
		363	cb => sub { $result_ready->send },
		364	);
		365
		366	# this "blocks" (while handling events) till the callback
		367	# calls send
		368	$result_ready->recv;
		369
		370	=head3 METHODS FOR PRODUCERS
		371
		372	These methods should only be used by the producing side, i.e. the
		373	code/module that eventually sends the signal. Note that it is also
		374	the producer side which creates the condvar in most cases, but it isn't
		375	uncommon for the consumer to create it as well.
325		376
326	=over 4	377	=over 4
327		378
		379	=item $cv->send (...)
		380
		381	Flag the condition as ready - a running C<< ->recv >> and all further
		382	calls to C<recv> will (eventually) return after this method has been
		383	called. If nobody is waiting the send will be remembered.
		384
		385	If a callback has been set on the condition variable, it is called
		386	immediately from within send.
		387
		388	Any arguments passed to the C<send> call will be returned by all
		389	future C<< ->recv >> calls.
		390
		391	=item $cv->croak ($error)
		392
		393	Similar to send, but causes all call's to C<< ->recv >> to invoke
		394	C<Carp::croak> with the given error message/object/scalar.
		395
		396	This can be used to signal any errors to the condition variable
		397	user/consumer.
		398
		399	=item $cv->begin ([group callback])
		400
328	=item $cv->wait	401	=item $cv->end
329		402
330	Wait (blocking if necessary) until the C<< ->broadcast >> method has been	403	These two methods are EXPERIMENTAL and MIGHT CHANGE.
		404
		405	These two methods can be used to combine many transactions/events into
		406	one. For example, a function that pings many hosts in parallel might want
		407	to use a condition variable for the whole process.
		408
		409	Every call to C<< ->begin >> will increment a counter, and every call to
		410	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
		411	>>, the (last) callback passed to C<begin> will be executed. That callback
		412	is I<supposed> to call C<< ->send >>, but that is not required. If no
		413	callback was set, C<send> will be called without any arguments.
		414
		415	Let's clarify this with the ping example:
		416
		417	my $cv = AnyEvent->condvar;
		418
		419	my %result;
		420	$cv->begin (sub { $cv->send (\%result) });
		421
		422	for my $host (@list_of_hosts) {
		423	$cv->begin;
		424	ping_host_then_call_callback $host, sub {
		425	$result{$host} = ...;
		426	$cv->end;
		427	};
		428	}
		429
		430	$cv->end;
		431
		432	This code fragment supposedly pings a number of hosts and calls
		433	C<send> after results for all then have have been gathered - in any
		434	order. To achieve this, the code issues a call to C<begin> when it starts
		435	each ping request and calls C<end> when it has received some result for
		436	it. Since C<begin> and C<end> only maintain a counter, the order in which
		437	results arrive is not relevant.
		438
		439	There is an additional bracketing call to C<begin> and C<end> outside the
		440	loop, which serves two important purposes: first, it sets the callback
		441	to be called once the counter reaches C<0>, and second, it ensures that
		442	C<send> is called even when C<no> hosts are being pinged (the loop
		443	doesn't execute once).
		444
		445	This is the general pattern when you "fan out" into multiple subrequests:
		446	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>
		447	is called at least once, and then, for each subrequest you start, call
		448	C<begin> and for each subrequest you finish, call C<end>.
		449
		450	=back
		451
		452	=head3 METHODS FOR CONSUMERS
		453
		454	These methods should only be used by the consuming side, i.e. the
		455	code awaits the condition.
		456
		457	=over 4
		458
		459	=item $cv->recv
		460
		461	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
331	called on c<$cv>, while servicing other watchers normally.	462	>> methods have been called on c<$cv>, while servicing other watchers
		463	normally.
332		464
333	You can only wait once on a condition - additional calls will return	465	You can only wait once on a condition - additional calls are valid but
334	immediately.	466	will return immediately.
		467
		468	If an error condition has been set by calling C<< ->croak >>, then this
		469	function will call C<croak>.
		470
		471	In list context, all parameters passed to C<send> will be returned,
		472	in scalar context only the first one will be returned.
335		473
336	Not all event models support a blocking wait - some die in that case	474	Not all event models support a blocking wait - some die in that case
337	(programs might want to do that to stay interactive), so I<if you are	475	(programs might want to do that to stay interactive), so I<if you are
338	using this from a module, never require a blocking wait>, but let the	476	using this from a module, never require a blocking wait>, but let the
339	caller decide whether the call will block or not (for example, by coupling	477	caller decide whether the call will block or not (for example, by coupling
340	condition variables with some kind of request results and supporting	478	condition variables with some kind of request results and supporting
341	callbacks so the caller knows that getting the result will not block,	479	callbacks so the caller knows that getting the result will not block,
342	while still suppporting blocking waits if the caller so desires).	480	while still supporting blocking waits if the caller so desires).
343		481
344	Another reason I<never> to C<< ->wait >> in a module is that you cannot	482	Another reason I<never> to C<< ->recv >> in a module is that you cannot
345	sensibly have two C<< ->wait >>'s in parallel, as that would require	483	sensibly have two C<< ->recv >>'s in parallel, as that would require
346	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	484	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
347	can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and	485	can supply.
348	L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
349	from different coroutines, however).
350		486
351	=item $cv->broadcast	487	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
		488	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
		489	versions and also integrates coroutines into AnyEvent, making blocking
		490	C<< ->recv >> calls perfectly safe as long as they are done from another
		491	coroutine (one that doesn't run the event loop).
352		492
353	Flag the condition as ready - a running C<< ->wait >> and all further	493	You can ensure that C<< -recv >> never blocks by setting a callback and
354	calls to C<wait> will (eventually) return after this method has been	494	only calling C<< ->recv >> from within that callback (or at a later
355	called. If nobody is waiting the broadcast will be remembered..	495	time). This will work even when the event loop does not support blocking
		496	waits otherwise.
		497
		498	=item $bool = $cv->ready
		499
		500	Returns true when the condition is "true", i.e. whether C<send> or
		501	C<croak> have been called.
		502
		503	=item $cb = $cv->cb ([new callback])
		504
		505	This is a mutator function that returns the callback set and optionally
		506	replaces it before doing so.
		507
		508	The callback will be called when the condition becomes "true", i.e. when
		509	C<send> or C<croak> are called. Calling C<recv> inside the callback
		510	or at any later time is guaranteed not to block.
356		511
357	=back	512	=back
358
359	Example:
360
361	# wait till the result is ready
362	my $result_ready = AnyEvent->condvar;
363
364	# do something such as adding a timer
365	# or socket watcher the calls $result_ready->broadcast
366	# when the "result" is ready.
367	# in this case, we simply use a timer:
368	my $w = AnyEvent->timer (
369	after => 1,
370	cb => sub { $result_ready->broadcast },
371	);
372
373	# this "blocks" (while handling events) till the watcher
374	# calls broadcast
375	$result_ready->wait;
376		513
377	=head1 GLOBAL VARIABLES AND FUNCTIONS	514	=head1 GLOBAL VARIABLES AND FUNCTIONS
378		515
379	=over 4	516	=over 4
380		517
…		…
386	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	523	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
387	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	524	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
388		525
389	The known classes so far are:	526	The known classes so far are:
390		527
391	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
392	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
393	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).	528	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
394	AnyEvent::Impl::Event based on Event, second best choice.	529	AnyEvent::Impl::Event based on Event, second best choice.
		530	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
395	AnyEvent::Impl::Glib based on Glib, third-best choice.	531	AnyEvent::Impl::Glib based on Glib, third-best choice.
396	AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable.
397	AnyEvent::Impl::Tk based on Tk, very bad choice.	532	AnyEvent::Impl::Tk based on Tk, very bad choice.
398	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).	533	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
399	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	534	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
400	AnyEvent::Impl::POE based on POE, not generic enough for full support.	535	AnyEvent::Impl::POE based on POE, not generic enough for full support.
401		536
…		…
414	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	549	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
415	if necessary. You should only call this function right before you would	550	if necessary. You should only call this function right before you would
416	have created an AnyEvent watcher anyway, that is, as late as possible at	551	have created an AnyEvent watcher anyway, that is, as late as possible at
417	runtime.	552	runtime.
418		553
		554	=item $guard = AnyEvent::post_detect { BLOCK }
		555
		556	Arranges for the code block to be executed as soon as the event model is
		557	autodetected (or immediately if this has already happened).
		558
		559	If called in scalar or list context, then it creates and returns an object
		560	that automatically removes the callback again when it is destroyed. See
		561	L<Coro::BDB> for a case where this is useful.
		562
		563	=item @AnyEvent::post_detect
		564
		565	If there are any code references in this array (you can C<push> to it
		566	before or after loading AnyEvent), then they will called directly after
		567	the event loop has been chosen.
		568
		569	You should check C<$AnyEvent::MODEL> before adding to this array, though:
		570	if it contains a true value then the event loop has already been detected,
		571	and the array will be ignored.
		572
		573	Best use C<AnyEvent::post_detect { BLOCK }> instead.
		574
419	=back	575	=back
420		576
421	=head1 WHAT TO DO IN A MODULE	577	=head1 WHAT TO DO IN A MODULE
422		578
423	As a module author, you should C<use AnyEvent> and call AnyEvent methods	579	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
426	Be careful when you create watchers in the module body - AnyEvent will	582	Be careful when you create watchers in the module body - AnyEvent will
427	decide which event module to use as soon as the first method is called, so	583	decide which event module to use as soon as the first method is called, so
428	by calling AnyEvent in your module body you force the user of your module	584	by calling AnyEvent in your module body you force the user of your module
429	to load the event module first.	585	to load the event module first.
430		586
431	Never call C<< ->wait >> on a condition variable unless you I<know> that	587	Never call C<< ->recv >> on a condition variable unless you I<know> that
432	the C<< ->broadcast >> method has been called on it already. This is	588	the C<< ->send >> method has been called on it already. This is
433	because it will stall the whole program, and the whole point of using	589	because it will stall the whole program, and the whole point of using
434	events is to stay interactive.	590	events is to stay interactive.
435		591
436	It is fine, however, to call C<< ->wait >> when the user of your module	592	It is fine, however, to call C<< ->recv >> when the user of your module
437	requests it (i.e. if you create a http request object ad have a method	593	requests it (i.e. if you create a http request object ad have a method
438	called C<results> that returns the results, it should call C<< ->wait >>	594	called C<results> that returns the results, it should call C<< ->recv >>
439	freely, as the user of your module knows what she is doing. always).	595	freely, as the user of your module knows what she is doing. always).
440		596
441	=head1 WHAT TO DO IN THE MAIN PROGRAM	597	=head1 WHAT TO DO IN THE MAIN PROGRAM
442		598
443	There will always be a single main program - the only place that should	599	There will always be a single main program - the only place that should
…		…
477		633
478	Provide read and write buffers and manages watchers for reads and writes.	634	Provide read and write buffers and manages watchers for reads and writes.
479		635
480	=item L<AnyEvent::Socket>	636	=item L<AnyEvent::Socket>
481		637
482	Provides a means to do non-blocking connects, accepts etc.	638	Provides various utility functions for (internet protocol) sockets,
		639	addresses and name resolution. Also functions to create non-blocking tcp
		640	connections or tcp servers, with IPv6 and SRV record support and more.
483		641
484	=item L<AnyEvent::HTTPD>	642	=item L<AnyEvent::HTTPD>
485		643
486	Provides a simple web application server framework.	644	Provides a simple web application server framework.
487		645
488	=item L<AnyEvent::DNS>	646	=item L<AnyEvent::DNS>
489		647
490	Provides asynchronous DNS resolver capabilities, beyond what	648	Provides rich asynchronous DNS resolver capabilities.
491	L<AnyEvent::Util> offers.
492		649
493	=item L<AnyEvent::FastPing>	650	=item L<AnyEvent::FastPing>
494		651
495	The fastest ping in the west.	652	The fastest ping in the west.
496		653
…		…
511		668
512	High level API for event-based execution flow control.	669	High level API for event-based execution flow control.
513		670
514	=item L<Coro>	671	=item L<Coro>
515		672
516	Has special support for AnyEvent.	673	Has special support for AnyEvent via L<Coro::AnyEvent>.
		674
		675	=item L<AnyEvent::AIO>, L<IO::AIO>
		676
		677	Truly asynchronous I/O, should be in the toolbox of every event
		678	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
		679	together.
		680
		681	=item L<AnyEvent::BDB>, L<BDB>
		682
		683	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
		684	IO::AIO and AnyEvent together.
517		685
518	=item L<IO::Lambda>	686	=item L<IO::Lambda>
519		687
520	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	688	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
521
522	=item L<IO::AIO>
523
524	Truly asynchronous I/O, should be in the toolbox of every event
525	programmer. Can be trivially made to use AnyEvent.
526
527	=item L<BDB>
528
529	Truly asynchronous Berkeley DB access. Can be trivially made to use
530	AnyEvent.
531		689
532	=back	690	=back
533		691
534	=cut	692	=cut
535		693
…		…
538	no warnings;	696	no warnings;
539	use strict;	697	use strict;
540		698
541	use Carp;	699	use Carp;
542		700
543	our $VERSION = '3.3';	701	our $VERSION = '3.6';
544	our $MODEL;	702	our $MODEL;
545		703
546	our $AUTOLOAD;	704	our $AUTOLOAD;
547	our @ISA;	705	our @ISA;
548		706
549	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	707	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
550		708
551	our @REGISTRY;	709	our @REGISTRY;
552		710
		711	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2)
		712
		713	{
		714	my $idx;
		715	$PROTOCOL{$_} = ++$idx
		716	for split /\s,\s/, $ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
		717	}
		718
553	my @models = (	719	my @models = (
554	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
555	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
556	[EV:: => AnyEvent::Impl::EV::],	720	[EV:: => AnyEvent::Impl::EV::],
557	[Event:: => AnyEvent::Impl::Event::],	721	[Event:: => AnyEvent::Impl::Event::],
558	[Glib:: => AnyEvent::Impl::Glib::],
559	[Tk:: => AnyEvent::Impl::Tk::],	722	[Tk:: => AnyEvent::Impl::Tk::],
560	[Wx:: => AnyEvent::Impl::POE::],	723	[Wx:: => AnyEvent::Impl::POE::],
561	[Prima:: => AnyEvent::Impl::POE::],	724	[Prima:: => AnyEvent::Impl::POE::],
562	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	725	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
563	# everything below here will not be autoprobed as the pureperl backend should work everywhere	726	# everything below here will not be autoprobed as the pureperl backend should work everywhere
		727	[Glib:: => AnyEvent::Impl::Glib::],
564	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	728	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
565	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	729	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
566	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	730	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
567	);	731	);
568		732
569	our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY);	733	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);
		734
		735	our @post_detect;
		736
		737	sub post_detect(&) {
		738	my ($cb) = @_;
		739
		740	if ($MODEL) {
		741	$cb->();
		742
		743	1
		744	} else {
		745	push @post_detect, $cb;
		746
		747	defined wantarray
		748	? bless \$cb, "AnyEvent::Util::PostDetect"
		749	: ()
		750	}
		751	}
		752
		753	sub AnyEvent::Util::PostDetect::DESTROY {
		754	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		755	}
570		756
571	sub detect() {	757	sub detect() {
572	unless ($MODEL) {	758	unless ($MODEL) {
573	no strict 'refs';	759	no strict 'refs';
574		760
…		…
608	last;	794	last;
609	}	795	}
610	}	796	}
611		797
612	$MODEL	798	$MODEL
613	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib.";	799	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
614	}	800	}
615	}	801	}
616		802
617	unshift @ISA, $MODEL;	803	unshift @ISA, $MODEL;
618	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	804	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		805
		806	(shift @post_detect)->() while @post_detect;
619	}	807	}
620		808
621	$MODEL	809	$MODEL
622	}	810	}
623		811
…		…
633	$class->$func (@_);	821	$class->$func (@_);
634	}	822	}
635		823
636	package AnyEvent::Base;	824	package AnyEvent::Base;
637		825
638	# default implementation for ->condvar, ->wait, ->broadcast	826	# default implementation for ->condvar
639		827
640	sub condvar {	828	sub condvar {
641	bless \my $flag, "AnyEvent::Base::CondVar"	829	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
642	}
643
644	sub AnyEvent::Base::CondVar::broadcast {
645	${$_[0]}++;
646	}
647
648	sub AnyEvent::Base::CondVar::wait {
649	AnyEvent->one_event while !${$_[0]};
650	}	830	}
651		831
652	# default implementation for ->signal	832	# default implementation for ->signal
653		833
654	our %SIG_CB;	834	our %SIG_CB;
…		…
728	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	908	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
729		909
730	undef $CHLD_W unless keys %PID_CB;	910	undef $CHLD_W unless keys %PID_CB;
731	}	911	}
732		912
		913	package AnyEvent::CondVar;
		914
		915	our @ISA = AnyEvent::CondVar::Base::;
		916
		917	package AnyEvent::CondVar::Base;
		918
		919	sub _send {
		920	# nop
		921	}
		922
		923	sub send {
		924	my $cv = shift;
		925	$cv->{_ae_sent} = [@_];
		926	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		927	$cv->_send;
		928	}
		929
		930	sub croak {
		931	$_[0]{_ae_croak} = $_[1];
		932	$_[0]->send;
		933	}
		934
		935	sub ready {
		936	$_[0]{_ae_sent}
		937	}
		938
		939	sub _wait {
		940	AnyEvent->one_event while !$_[0]{_ae_sent};
		941	}
		942
		943	sub recv {
		944	$_[0]->_wait;
		945
		946	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		947	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		948	}
		949
		950	sub cb {
		951	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		952	$_[0]{_ae_cb}
		953	}
		954
		955	sub begin {
		956	++$_[0]{_ae_counter};
		957	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		958	}
		959
		960	sub end {
		961	return if --$_[0]{_ae_counter};
		962	&{ $_[0]{_ae_end_cb} \|\| sub { $_[0]->send } };
		963	}
		964
		965	# undocumented/compatibility with pre-3.4
		966	*broadcast = \&send;
		967	*wait = \&_wait;
		968
733	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	969	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
734		970
735	This is an advanced topic that you do not normally need to use AnyEvent in	971	This is an advanced topic that you do not normally need to use AnyEvent in
736	a module. This section is only of use to event loop authors who want to	972	a module. This section is only of use to event loop authors who want to
737	provide AnyEvent compatibility.	973	provide AnyEvent compatibility.
…		…
793	model it chooses.	1029	model it chooses.
794		1030
795	=item C<PERL_ANYEVENT_MODEL>	1031	=item C<PERL_ANYEVENT_MODEL>
796		1032
797	This can be used to specify the event model to be used by AnyEvent, before	1033	This can be used to specify the event model to be used by AnyEvent, before
798	autodetection and -probing kicks in. It must be a string consisting	1034	auto detection and -probing kicks in. It must be a string consisting
799	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1035	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
800	and the resulting module name is loaded and if the load was successful,	1036	and the resulting module name is loaded and if the load was successful,
801	used as event model. If it fails to load AnyEvent will proceed with	1037	used as event model. If it fails to load AnyEvent will proceed with
802	autodetection and -probing.	1038	auto detection and -probing.
803		1039
804	This functionality might change in future versions.	1040	This functionality might change in future versions.
805		1041
806	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1042	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
807	could start your program like this:	1043	could start your program like this:
808		1044
809	PERL_ANYEVENT_MODEL=Perl perl ...	1045	PERL_ANYEVENT_MODEL=Perl perl ...
		1046
		1047	=item C<PERL_ANYEVENT_PROTOCOLS>
		1048
		1049	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1050	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1051	of auto probing).
		1052
		1053	Must be set to a comma-separated list of protocols or address families,
		1054	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1055	used, and preference will be given to protocols mentioned earlier in the
		1056	list.
		1057
		1058	This variable can effectively be used for denial-of-service attacks
		1059	against local programs (e.g. when setuid), although the impact is likely
		1060	small, as the program has to handle connection errors already-
		1061
		1062	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1063	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1064	- only support IPv4, never try to resolve or contact IPv6
		1065	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1066	IPv6, but prefer IPv6 over IPv4.
		1067
		1068	=item C<PERL_ANYEVENT_EDNS0>
		1069
		1070	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1071	for DNS. This extension is generally useful to reduce DNS traffic, but
		1072	some (broken) firewalls drop such DNS packets, which is why it is off by
		1073	default.
		1074
		1075	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1076	EDNS0 in its DNS requests.
810		1077
811	=back	1078	=back
812		1079
813	=head1 EXAMPLE PROGRAM	1080	=head1 EXAMPLE PROGRAM
814		1081
…		…
825	poll => 'r',	1092	poll => 'r',
826	cb => sub {	1093	cb => sub {
827	warn "io event <$_[0]>\n"; # will always output <r>	1094	warn "io event <$_[0]>\n"; # will always output <r>
828	chomp (my $input = <STDIN>); # read a line	1095	chomp (my $input = <STDIN>); # read a line
829	warn "read: $input\n"; # output what has been read	1096	warn "read: $input\n"; # output what has been read
830	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1097	$cv->send if $input =~ /^q/i; # quit program if /^q/i
831	},	1098	},
832	);	1099	);
833		1100
834	my $time_watcher; # can only be used once	1101	my $time_watcher; # can only be used once
835		1102
…		…
840	});	1107	});
841	}	1108	}
842		1109
843	new_timer; # create first timer	1110	new_timer; # create first timer
844		1111
845	$cv->wait; # wait until user enters /^q/i	1112	$cv->recv; # wait until user enters /^q/i
846		1113
847	=head1 REAL-WORLD EXAMPLE	1114	=head1 REAL-WORLD EXAMPLE
848		1115
849	Consider the L<Net::FCP> module. It features (among others) the following	1116	Consider the L<Net::FCP> module. It features (among others) the following
850	API calls, which are to freenet what HTTP GET requests are to http:	1117	API calls, which are to freenet what HTTP GET requests are to http:
…		…
900	syswrite $txn->{fh}, $txn->{request}	1167	syswrite $txn->{fh}, $txn->{request}
901	or die "connection or write error";	1168	or die "connection or write error";
902	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1169	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
903		1170
904	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1171	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
905	result and signals any possible waiters that the request ahs finished:	1172	result and signals any possible waiters that the request has finished:
906		1173
907	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1174	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
908		1175
909	if (end-of-file or data complete) {	1176	if (end-of-file or data complete) {
910	$txn->{result} = $txn->{buf};	1177	$txn->{result} = $txn->{buf};
911	$txn->{finished}->broadcast;	1178	$txn->{finished}->send;
912	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1179	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
913	}	1180	}
914		1181
915	The C<result> method, finally, just waits for the finished signal (if the	1182	The C<result> method, finally, just waits for the finished signal (if the
916	request was already finished, it doesn't wait, of course, and returns the	1183	request was already finished, it doesn't wait, of course, and returns the
917	data:	1184	data:
918		1185
919	$txn->{finished}->wait;	1186	$txn->{finished}->recv;
920	return $txn->{result};	1187	return $txn->{result};
921		1188
922	The actual code goes further and collects all errors (C<die>s, exceptions)	1189	The actual code goes further and collects all errors (C<die>s, exceptions)
923	that occured during request processing. The C<result> method detects	1190	that occurred during request processing. The C<result> method detects
924	whether an exception as thrown (it is stored inside the $txn object)	1191	whether an exception as thrown (it is stored inside the $txn object)
925	and just throws the exception, which means connection errors and other	1192	and just throws the exception, which means connection errors and other
926	problems get reported tot he code that tries to use the result, not in a	1193	problems get reported tot he code that tries to use the result, not in a
927	random callback.	1194	random callback.
928		1195
…		…
959		1226
960	my $quit = AnyEvent->condvar;	1227	my $quit = AnyEvent->condvar;
961		1228
962	$fcp->txn_client_get ($url)->cb (sub {	1229	$fcp->txn_client_get ($url)->cb (sub {
963	...	1230	...
964	$quit->broadcast;	1231	$quit->send;
965	});	1232	});
966		1233
967	$quit->wait;	1234	$quit->recv;
968		1235
969		1236
970	=head1 BENCHMARKS	1237	=head1 BENCHMARKS
971		1238
972	To give you an idea of the performance and overheads that AnyEvent adds	1239	To give you an idea of the performance and overheads that AnyEvent adds
…		…
974	of various event loops I prepared some benchmarks.	1241	of various event loops I prepared some benchmarks.
975		1242
976	=head2 BENCHMARKING ANYEVENT OVERHEAD	1243	=head2 BENCHMARKING ANYEVENT OVERHEAD
977		1244
978	Here is a benchmark of various supported event models used natively and	1245	Here is a benchmark of various supported event models used natively and
979	through anyevent. The benchmark creates a lot of timers (with a zero	1246	through AnyEvent. The benchmark creates a lot of timers (with a zero
980	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	1247	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
981	which it is), lets them fire exactly once and destroys them again.	1248	which it is), lets them fire exactly once and destroys them again.
982		1249
983	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1250	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
984	distribution.	1251	distribution.
…		…
1001	all watchers, to avoid adding memory overhead. That means closure creation	1268	all watchers, to avoid adding memory overhead. That means closure creation
1002	and memory usage is not included in the figures.	1269	and memory usage is not included in the figures.
1003		1270
1004	I<invoke> is the time, in microseconds, used to invoke a simple	1271	I<invoke> is the time, in microseconds, used to invoke a simple
1005	callback. The callback simply counts down a Perl variable and after it was	1272	callback. The callback simply counts down a Perl variable and after it was
1006	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1273	invoked "watcher" times, it would C<< ->send >> a condvar once to
1007	signal the end of this phase.	1274	signal the end of this phase.
1008		1275
1009	I<destroy> is the time, in microseconds, that it takes to destroy a single	1276	I<destroy> is the time, in microseconds, that it takes to destroy a single
1010	watcher.	1277	watcher.
1011		1278
…		…
1071	file descriptor is dup()ed for each watcher. This shows that the dup()	1338	file descriptor is dup()ed for each watcher. This shows that the dup()
1072	employed by some adaptors is not a big performance issue (it does incur a	1339	employed by some adaptors is not a big performance issue (it does incur a
1073	hidden memory cost inside the kernel which is not reflected in the figures	1340	hidden memory cost inside the kernel which is not reflected in the figures
1074	above).	1341	above).
1075		1342
1076	C<POE>, regardless of underlying event loop (whether using its pure	1343	C<POE>, regardless of underlying event loop (whether using its pure perl
1077	perl select-based backend or the Event module, the POE-EV backend	1344	select-based backend or the Event module, the POE-EV backend couldn't
1078	couldn't be tested because it wasn't working) shows abysmal performance	1345	be tested because it wasn't working) shows abysmal performance and
1079	and memory usage: Watchers use almost 30 times as much memory as	1346	memory usage with AnyEvent: Watchers use almost 30 times as much memory
1080	EV watchers, and 10 times as much memory as Event (the high memory	1347	as EV watchers, and 10 times as much memory as Event (the high memory
1081	requirements are caused by requiring a session for each watcher). Watcher	1348	requirements are caused by requiring a session for each watcher). Watcher
1082	invocation speed is almost 900 times slower than with AnyEvent's pure perl	1349	invocation speed is almost 900 times slower than with AnyEvent's pure perl
		1350	implementation.
		1351
1083	implementation. The design of the POE adaptor class in AnyEvent can not	1352	The design of the POE adaptor class in AnyEvent can not really account
1084	really account for this, as session creation overhead is small compared	1353	for the performance issues, though, as session creation overhead is
1085	to execution of the state machine, which is coded pretty optimally within	1354	small compared to execution of the state machine, which is coded pretty
1086	L<AnyEvent::Impl::POE>. POE simply seems to be abysmally slow.	1355	optimally within L<AnyEvent::Impl::POE> (and while everybody agrees that
		1356	using multiple sessions is not a good approach, especially regarding
		1357	memory usage, even the author of POE could not come up with a faster
		1358	design).
1087		1359
1088	=head3 Summary	1360	=head3 Summary
1089		1361
1090	=over 4	1362	=over 4
1091		1363
…		…
1102		1374
1103	=back	1375	=back
1104		1376
1105	=head2 BENCHMARKING THE LARGE SERVER CASE	1377	=head2 BENCHMARKING THE LARGE SERVER CASE
1106		1378
1107	This benchmark atcually benchmarks the event loop itself. It works by	1379	This benchmark actually benchmarks the event loop itself. It works by
1108	creating a number of "servers": each server consists of a socketpair, a	1380	creating a number of "servers": each server consists of a socket pair, a
1109	timeout watcher that gets reset on activity (but never fires), and an I/O	1381	timeout watcher that gets reset on activity (but never fires), and an I/O
1110	watcher waiting for input on one side of the socket. Each time the socket	1382	watcher waiting for input on one side of the socket. Each time the socket
1111	watcher reads a byte it will write that byte to a random other "server".	1383	watcher reads a byte it will write that byte to a random other "server".
1112		1384
1113	The effect is that there will be a lot of I/O watchers, only part of which	1385	The effect is that there will be a lot of I/O watchers, only part of which
1114	are active at any one point (so there is a constant number of active	1386	are active at any one point (so there is a constant number of active
1115	fds for each loop iterstaion, but which fds these are is random). The	1387	fds for each loop iteration, but which fds these are is random). The
1116	timeout is reset each time something is read because that reflects how	1388	timeout is reset each time something is read because that reflects how
1117	most timeouts work (and puts extra pressure on the event loops).	1389	most timeouts work (and puts extra pressure on the event loops).
1118		1390
1119	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1391	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1120	(1%) are active. This mirrors the activity of large servers with many	1392	(1%) are active. This mirrors the activity of large servers with many
1121	connections, most of which are idle at any one point in time.	1393	connections, most of which are idle at any one point in time.
1122		1394
1123	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1395	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1124	distribution.	1396	distribution.
…		…
1126	=head3 Explanation of the columns	1398	=head3 Explanation of the columns
1127		1399
1128	I<sockets> is the number of sockets, and twice the number of "servers" (as	1400	I<sockets> is the number of sockets, and twice the number of "servers" (as
1129	each server has a read and write socket end).	1401	each server has a read and write socket end).
1130		1402
1131	I<create> is the time it takes to create a socketpair (which is	1403	I<create> is the time it takes to create a socket pair (which is
1132	nontrivial) and two watchers: an I/O watcher and a timeout watcher.	1404	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1133		1405
1134	I<request>, the most important value, is the time it takes to handle a	1406	I<request>, the most important value, is the time it takes to handle a
1135	single "request", that is, reading the token from the pipe and forwarding	1407	single "request", that is, reading the token from the pipe and forwarding
1136	it to another server. This includes deleting the old timeout and creating	1408	it to another server. This includes deleting the old timeout and creating
…		…
1170		1442
1171	=head3 Summary	1443	=head3 Summary
1172		1444
1173	=over 4	1445	=over 4
1174		1446
1175	=item * The pure perl implementation performs extremely well, considering	1447	=item * The pure perl implementation performs extremely well.
1176	that it uses select.
1177		1448
1178	=item * Avoid Glib or POE in large projects where performance matters.	1449	=item * Avoid Glib or POE in large projects where performance matters.
1179		1450
1180	=back	1451	=back
1181		1452
…		…
1210	speed most when you have lots of watchers, not when you only have a few of	1481	speed most when you have lots of watchers, not when you only have a few of
1211	them).	1482	them).
1212		1483
1213	EV is again fastest.	1484	EV is again fastest.
1214		1485
1215	Perl again comes second. It is noticably faster than the C-based event	1486	Perl again comes second. It is noticeably faster than the C-based event
1216	loops Event and Glib, although the difference is too small to really	1487	loops Event and Glib, although the difference is too small to really
1217	matter.	1488	matter.
1218		1489
1219	POE also performs much better in this case, but is is still far behind the	1490	POE also performs much better in this case, but is is still far behind the
1220	others.	1491	others.
…		…
1230		1501
1231		1502
1232	=head1 FORK	1503	=head1 FORK
1233		1504
1234	Most event libraries are not fork-safe. The ones who are usually are	1505	Most event libraries are not fork-safe. The ones who are usually are
1235	because they are so inefficient. Only L<EV> is fully fork-aware.	1506	because they rely on inefficient but fork-safe C<select> or C<poll>
		1507	calls. Only L<EV> is fully fork-aware.
1236		1508
1237	If you have to fork, you must either do so I<before> creating your first	1509	If you have to fork, you must either do so I<before> creating your first
1238	watcher OR you must not use AnyEvent at all in the child.	1510	watcher OR you must not use AnyEvent at all in the child.
1239		1511
1240		1512
…		…
1252		1524
1253	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1525	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1254		1526
1255	use AnyEvent;	1527	use AnyEvent;
1256		1528
		1529	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
		1530	be used to probe what backend is used and gain other information (which is
		1531	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
		1532
1257		1533
1258	=head1 SEE ALSO	1534	=head1 SEE ALSO
1259		1535
1260	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,	1536	Utility functions: L<AnyEvent::Util>.
1261	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,	1537
		1538	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1262	L<Event::Lib>, L<Qt>, L<POE>.	1539	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1263		1540
1264	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,	1541	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1265	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,	1542	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1266	L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>,	1543	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1267	L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>.	1544	L<AnyEvent::Impl::POE>.
1268		1545
		1546	Non-blocking file handles, sockets, TCP clients and
		1547	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1548
		1549	Asynchronous DNS: L<AnyEvent::DNS>.
		1550
		1551	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
		1552
1269	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1553	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1270		1554
1271		1555
1272	=head1 AUTHOR	1556	=head1 AUTHOR
1273		1557
1274	Marc Lehmann <schmorp@schmorp.de>	1558	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.102 by root, Sun Apr 27 21:16:26 2008 UTC vs. Revision 1.129 by elmex, Sat May 24 15:19:30 2008 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.102 by root, Sun Apr 27 21:16:26 2008 UTC vs.
Revision 1.129 by elmex, Sat May 24 15:19:30 2008 UTC