[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 1.143 by root, Wed May 28 23:57:38 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?
…		…
48	isn't itself. What's worse, all the potential users of your module are	48	isn't itself. What's worse, all the potential users of your module are
49	I<also> forced to use the same event loop you use.	49	I<also> forced to use the same event loop you use.
50		50
51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
53	with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if	53	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
54	your module uses one of those, every user of your module has to use it,	54	your module uses one of those, every user of your module has to use it,
55	too. But if your module uses AnyEvent, it works transparently with all	55	too. But if your module uses AnyEvent, it works transparently with all
56	event models it supports (including stuff like POE and IO::Async, as long	56	event models it supports (including stuff like POE and IO::Async, as long
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, AnyEvent comes with a big (and fully optional!) toolbox
		68	of useful functionality, such as an asynchronous DNS resolver, 100%
		69	non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
		70	such as Windows) and lots of real-world knowledge and workarounds for
		71	platform bugs and differences.
		72
67	Of course, if you want lots of policy (this can arguably be somewhat	73	Now, if you I<do want> lots of policy (this can arguably be somewhat
68	useful) and you want to force your users to use the one and only event	74	useful) and you want to force your users to use the one and only event
69	model, you should I<not> use this module.	75	model, you should I<not> use this module.
70		76
71	=head1 DESCRIPTION	77	=head1 DESCRIPTION
72		78
…		…
78	The interface itself is vaguely similar, but not identical to the L<Event>	84	The interface itself is vaguely similar, but not identical to the L<Event>
79	module.	85	module.
80		86
81	During the first call of any watcher-creation method, the module tries	87	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	88	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>,	89	following modules is already loaded: L<EV>,
84	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	90	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	91	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	92	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	93	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	94	be successfully loaded will be used. If, after this, still none could be
…		…
102	starts using it, all bets are off. Maybe you should tell their authors to	108	starts using it, all bets are off. Maybe you should tell their authors to
103	use AnyEvent so their modules work together with others seamlessly...	109	use AnyEvent so their modules work together with others seamlessly...
104		110
105	The pure-perl implementation of AnyEvent is called	111	The pure-perl implementation of AnyEvent is called
106	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	112	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
107	explicitly.	113	explicitly and enjoy the high availability of that event loop :)
108		114
109	=head1 WATCHERS	115	=head1 WATCHERS
110		116
111	AnyEvent has the central concept of a I<watcher>, which is an object that	117	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	118	stores relevant data for each kind of event you are waiting for, such as
113	the callback to call, the filehandle to watch, etc.	119	the callback to call, the file handle to watch, etc.
114		120
115	These watchers are normal Perl objects with normal Perl lifetime. After	121	These watchers are normal Perl objects with normal Perl lifetime. After
116	creating a watcher it will immediately "watch" for events and invoke the	122	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	123	callback when the event occurs (of course, only when the event model
118	is in control).	124	is in control).
…		…
227	timers.	233	timers.
228		234
229	AnyEvent always prefers relative timers, if available, matching the	235	AnyEvent always prefers relative timers, if available, matching the
230	AnyEvent API.	236	AnyEvent API.
231		237
		238	AnyEvent has two additional methods that return the "current time":
		239
		240	=over 4
		241
		242	=item AnyEvent->time
		243
		244	This returns the "current wallclock time" as a fractional number of
		245	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
		246	return, and the result is guaranteed to be compatible with those).
		247
		248	It progresses independently of any event loop processing.
		249
		250	In almost all cases (in all cases if you don't care), this is the function
		251	to call when you want to know the current time.
		252
		253	=item AnyEvent->now
		254
		255	This also returns the "current wallclock time", but unlike C<time>, above,
		256	this value might change only once per event loop iteration, depending on
		257	the event loop (most return the same time as C<time>, above). This is the
		258	time that AnyEvent timers get scheduled against.
		259
		260	For a practical example of when these times differ, consider L<Event::Lib>
		261	and L<EV> and the following set-up:
		262
		263	The event loop is running and has just invoked one of your callback at
		264	time=500 (assume no other callbacks delay processing). In your callback,
		265	you wait a second by executing C<sleep 1> (blocking the process for a
		266	second) and then (at time=501) you create a relative timer that fires
		267	after three seconds.
		268
		269	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
		270	both return C<501>, because that is the current time, and the timer will
		271	be scheduled to fire at time=504 (C<501> + C<3>).
		272
		273	With L<EV>m C<< AnyEvent->time >> returns C<501> (as that is the current
		274	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
		275	last event processing phase started. With L<EV>, your timer gets scheduled
		276	to run at time=503 (C<500> + C<3>).
		277
		278	In one sense, L<Event::Lib> is more exact, as it uses the current time
		279	regardless of any delays introduced by event processing. However, most
		280	callbacks do not expect large delays in processing, so this causes a
		281	higher drift (and a lot more syscalls to get the current time).
		282
		283	In another sense, L<EV> is more exact, as your timer will be scheduled at
		284	the same time, regardless of how long event processing actually took.
		285
		286	In either case, if you care (and in most cases, you don't), then you
		287	can get whatever behaviour you want with any event loop, by taking the
		288	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
		289	account.
		290
		291	=back
		292
232	=head2 SIGNAL WATCHERS	293	=head2 SIGNAL WATCHERS
233		294
234	You can watch for signals using a signal watcher, C<signal> is the signal	295	You can watch for signals using a signal watcher, C<signal> is the signal
235	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to	296	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to
236	be invoked whenever a signal occurs.	297	be invoked whenever a signal occurs.
237		298
238	Although the callback might get passed parameters, their value and	299	Although the callback might get passed parameters, their value and
239	presence is undefined and you cannot rely on them. Portable AnyEvent	300	presence is undefined and you cannot rely on them. Portable AnyEvent
240	callbacks cannot use arguments passed to signal watcher callbacks.	301	callbacks cannot use arguments passed to signal watcher callbacks.
241		302
242	Multiple signal occurances can be clumped together into one callback	303	Multiple signal occurrences can be clumped together into one callback
243	invocation, and callback invocation will be synchronous. synchronous means	304	invocation, and callback invocation will be synchronous. Synchronous means
244	that it might take a while until the signal gets handled by the process,	305	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.	306	but it is guaranteed not to interrupt any other callbacks.
246		307
247	The main advantage of using these watchers is that you can share a signal	308	The main advantage of using these watchers is that you can share a signal
248	between multiple watchers.	309	between multiple watchers.
249		310
250	This watcher might use C<%SIG>, so programs overwriting those signals	311	This watcher might use C<%SIG>, so programs overwriting those signals
…		…
279		340
280	Example: fork a process and wait for it	341	Example: fork a process and wait for it
281		342
282	my $done = AnyEvent->condvar;	343	my $done = AnyEvent->condvar;
283		344
284	AnyEvent::detect; # force event module to be initialised
285
286	my $pid = fork or exit 5;	345	my $pid = fork or exit 5;
287		346
288	my $w = AnyEvent->child (	347	my $w = AnyEvent->child (
289	pid => $pid,	348	pid => $pid,
290	cb => sub {	349	cb => sub {
291	my ($pid, $status) = @_;	350	my ($pid, $status) = @_;
292	warn "pid $pid exited with status $status";	351	warn "pid $pid exited with status $status";
293	$done->broadcast;	352	$done->send;
294	},	353	},
295	);	354	);
296		355
297	# do something else, then wait for process exit	356	# do something else, then wait for process exit
298	$done->wait;	357	$done->recv;
299		358
300	=head2 CONDITION VARIABLES	359	=head2 CONDITION VARIABLES
301		360
302	If you are familiar with some event loops you will know that all of them	361	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	362	require you to run some blocking "loop", "run" or similar function that
…		…
312	Condition variables can be created by calling the C<< AnyEvent->condvar	371	Condition variables can be created by calling the C<< AnyEvent->condvar
313	>> method, usually without arguments. The only argument pair allowed is	372	>> method, usually without arguments. The only argument pair allowed is
314	C<cb>, which specifies a callback to be called when the condition variable	373	C<cb>, which specifies a callback to be called when the condition variable
315	becomes true.	374	becomes true.
316		375
317	After creation, the conditon variable is "false" until it becomes "true"	376	After creation, the condition variable is "false" until it becomes "true"
318	by calling the C<broadcast> method.	377	by calling the C<send> method (or calling the condition variable as if it
		378	were a callback, read about the caveats in the description for the C<<
		379	->send >> method).
319		380
320	Condition variables are similar to callbacks, except that you can	381	Condition variables are similar to callbacks, except that you can
321	optionally wait for them. They can also be called merge points - points	382	optionally wait for them. They can also be called merge points - points
322	in time where multiple outstandign events have been processed. And yet	383	in time where multiple outstanding events have been processed. And yet
323	another way to call them is transations - each condition variable can be	384	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	385	used to represent a transaction, which finishes at some point and delivers
325	a result.	386	a result.
326		387
327	Condition variables are very useful to signal that something has finished,	388	Condition variables are very useful to signal that something has finished,
328	for example, if you write a module that does asynchronous http requests,	389	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	390	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	391	availability of results. The user can either act when the callback is
331	called or can synchronously C<< ->wait >> for the results.	392	called or can synchronously C<< ->recv >> for the results.
332		393
333	You can also use them to simulate traditional event loops - for example,	394	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	395	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	396	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.	397	button of your app, which would C<< ->send >> the "quit" event.
337		398
338	Note that condition variables recurse into the event loop - if you have	399	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	400	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	401	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,	402	you should avoid making a blocking wait yourself, at least in callbacks,
342	as this asks for trouble.	403	as this asks for trouble.
343		404
344	Condition variables are represented by hash refs in perl, and the keys	405	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	407	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	408	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
348	it's C<new> method in your own C<new> method.	409	it's C<new> method in your own C<new> method.
349		410
350	There are two "sides" to a condition variable - the "producer side" which	411	There are two "sides" to a condition variable - the "producer side" which
351	eventually calls C<< -> broadcast >>, and the "consumer side", which waits	412	eventually calls C<< -> send >>, and the "consumer side", which waits
352	for the broadcast to occur.	413	for the send to occur.
353		414
354	Example:	415	Example: wait for a timer.
355		416
356	# wait till the result is ready	417	# wait till the result is ready
357	my $result_ready = AnyEvent->condvar;	418	my $result_ready = AnyEvent->condvar;
358		419
359	# do something such as adding a timer	420	# do something such as adding a timer
360	# or socket watcher the calls $result_ready->broadcast	421	# or socket watcher the calls $result_ready->send
361	# when the "result" is ready.	422	# when the "result" is ready.
362	# in this case, we simply use a timer:	423	# in this case, we simply use a timer:
363	my $w = AnyEvent->timer (	424	my $w = AnyEvent->timer (
364	after => 1,	425	after => 1,
365	cb => sub { $result_ready->broadcast },	426	cb => sub { $result_ready->send },
366	);	427	);
367		428
368	# this "blocks" (while handling events) till the callback	429	# this "blocks" (while handling events) till the callback
369	# calls broadcast	430	# calls send
370	$result_ready->wait;	431	$result_ready->recv;
		432
		433	Example: wait for a timer, but take advantage of the fact that
		434	condition variables are also code references.
		435
		436	my $done = AnyEvent->condvar;
		437	my $delay = AnyEvent->timer (after => 5, cb => $done);
		438	$done->recv;
371		439
372	=head3 METHODS FOR PRODUCERS	440	=head3 METHODS FOR PRODUCERS
373		441
374	These methods should only be used by the producing side, i.e. the	442	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	443	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	444	the producer side which creates the condvar in most cases, but it isn't
377	uncommon for the consumer to create it as well.	445	uncommon for the consumer to create it as well.
378		446
379	=over 4	447	=over 4
380		448
381	=item $cv->broadcast (...)	449	=item $cv->send (...)
382		450
383	Flag the condition as ready - a running C<< ->wait >> and all further	451	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	452	calls to C<recv> will (eventually) return after this method has been
385	called. If nobody is waiting the broadcast will be remembered.	453	called. If nobody is waiting the send will be remembered.
386		454
387	If a callback has been set on the condition variable, it is called	455	If a callback has been set on the condition variable, it is called
388	immediately from within broadcast.	456	immediately from within send.
389		457
390	Any arguments passed to the C<broadcast> call will be returned by all	458	Any arguments passed to the C<send> call will be returned by all
391	future C<< ->wait >> calls.	459	future C<< ->recv >> calls.
		460
		461	Condition variables are overloaded so one can call them directly
		462	(as a code reference). Calling them directly is the same as calling
		463	C<send>. Note, however, that many C-based event loops do not handle
		464	overloading, so as tempting as it may be, passing a condition variable
		465	instead of a callback does not work. Both the pure perl and EV loops
		466	support overloading, however, as well as all functions that use perl to
		467	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
		468	example).
392		469
393	=item $cv->croak ($error)	470	=item $cv->croak ($error)
394		471
395	Similar to broadcast, but causes all call's wait C<< ->wait >> to invoke	472	Similar to send, but causes all call's to C<< ->recv >> to invoke
396	C<Carp::croak> with the given error message/object/scalar.	473	C<Carp::croak> with the given error message/object/scalar.
397		474
398	This can be used to signal any errors to the condition variable	475	This can be used to signal any errors to the condition variable
399	user/consumer.	476	user/consumer.
400		477
401	=item $cv->begin ([group callback])	478	=item $cv->begin ([group callback])
402		479
403	=item $cv->end	480	=item $cv->end
		481
		482	These two methods are EXPERIMENTAL and MIGHT CHANGE.
404		483
405	These two methods can be used to combine many transactions/events into	484	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	485	one. For example, a function that pings many hosts in parallel might want
407	to use a condition variable for the whole process.	486	to use a condition variable for the whole process.
408		487
409	Every call to C<< ->begin >> will increment a counter, and every call to	488	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	489	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	490	>>, 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	491	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.	492	callback was set, C<send> will be called without any arguments.
414		493
415	Let's clarify this with the ping example:	494	Let's clarify this with the ping example:
416		495
417	my $cv = AnyEvent->condvar;	496	my $cv = AnyEvent->condvar;
418		497
419	my %result;	498	my %result;
420	$cv->begin (sub { $cv->broadcast (\%result) });	499	$cv->begin (sub { $cv->send (\%result) });
421		500
422	for my $host (@list_of_hosts) {	501	for my $host (@list_of_hosts) {
423	$cv->begin;	502	$cv->begin;
424	ping_host_then_call_callback $host, sub {	503	ping_host_then_call_callback $host, sub {
425	$result{$host} = ...;	504	$result{$host} = ...;
…		…
428	}	507	}
429		508
430	$cv->end;	509	$cv->end;
431		510
432	This code fragment supposedly pings a number of hosts and calls	511	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	512	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	513	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	514	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	515	it. Since C<begin> and C<end> only maintain a counter, the order in which
437	results arrive is not relevant.	516	results arrive is not relevant.
438		517
439	There is an additional bracketing call to C<begin> and C<end> outside the	518	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	519	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	520	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	521	C<send> is called even when C<no> hosts are being pinged (the loop
443	doesn't execute once).	522	doesn't execute once).
444		523
445	This is the general pattern when you "fan out" into multiple subrequests:	524	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>	525	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	526	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>.	527	C<begin> and for each subrequest you finish, call C<end>.
449		528
450	=back	529	=back
451		530
452	=head3 METHODS FOR CONSUMERS	531	=head3 METHODS FOR CONSUMERS
453		532
454	These methods should only be used by the consuming side, i.e. the	533	These methods should only be used by the consuming side, i.e. the
455	code awaits the condition.	534	code awaits the condition.
456		535
457	=item $cv->wait	536	=over 4
458		537
		538	=item $cv->recv
		539
459	Wait (blocking if necessary) until the C<< ->broadcast >> or C<< ->croak	540	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
460	>> methods have been called on c<$cv>, while servicing other watchers	541	>> methods have been called on c<$cv>, while servicing other watchers
461	normally.	542	normally.
462		543
463	You can only wait once on a condition - additional calls are valid but	544	You can only wait once on a condition - additional calls are valid but
464	will return immediately.	545	will return immediately.
465		546
466	If an error condition has been set by calling C<< ->croak >>, then this	547	If an error condition has been set by calling C<< ->croak >>, then this
467	function will call C<croak>.	548	function will call C<croak>.
468		549
469	In list context, all parameters passed to C<broadcast> will be returned,	550	In list context, all parameters passed to C<send> will be returned,
470	in scalar context only the first one will be returned.	551	in scalar context only the first one will be returned.
471		552
472	Not all event models support a blocking wait - some die in that case	553	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	554	(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	555	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	556	caller decide whether the call will block or not (for example, by coupling
476	condition variables with some kind of request results and supporting	557	condition variables with some kind of request results and supporting
477	callbacks so the caller knows that getting the result will not block,	558	callbacks so the caller knows that getting the result will not block,
478	while still suppporting blocking waits if the caller so desires).	559	while still supporting blocking waits if the caller so desires).
479		560
480	Another reason I<never> to C<< ->wait >> in a module is that you cannot	561	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	562	sensibly have two C<< ->recv >>'s in parallel, as that would require
482	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	563	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
483	can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and	564	can supply.
484	L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
485	from different coroutines, however).
486		565
		566	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
		567	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
		568	versions and also integrates coroutines into AnyEvent, making blocking
		569	C<< ->recv >> calls perfectly safe as long as they are done from another
		570	coroutine (one that doesn't run the event loop).
		571
487	You can ensure that C<< -wait >> never blocks by setting a callback and	572	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	573	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	574	time). This will work even when the event loop does not support blocking
490	waits otherwise.	575	waits otherwise.
		576
		577	=item $bool = $cv->ready
		578
		579	Returns true when the condition is "true", i.e. whether C<send> or
		580	C<croak> have been called.
		581
		582	=item $cb = $cv->cb ([new callback])
		583
		584	This is a mutator function that returns the callback set and optionally
		585	replaces it before doing so.
		586
		587	The callback will be called when the condition becomes "true", i.e. when
		588	C<send> or C<croak> are called. Calling C<recv> inside the callback
		589	or at any later time is guaranteed not to block.
491		590
492	=back	591	=back
493		592
494	=head1 GLOBAL VARIABLES AND FUNCTIONS	593	=head1 GLOBAL VARIABLES AND FUNCTIONS
495		594
…		…
503	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	602	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
504	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	603	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
505		604
506	The known classes so far are:	605	The known classes so far are:
507		606
508	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
509	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
510	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).	607	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
511	AnyEvent::Impl::Event based on Event, second best choice.	608	AnyEvent::Impl::Event based on Event, second best choice.
512	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	609	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
513	AnyEvent::Impl::Glib based on Glib, third-best choice.	610	AnyEvent::Impl::Glib based on Glib, third-best choice.
514	AnyEvent::Impl::Tk based on Tk, very bad choice.	611	AnyEvent::Impl::Tk based on Tk, very bad choice.
…		…
531	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	628	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
532	if necessary. You should only call this function right before you would	629	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	630	have created an AnyEvent watcher anyway, that is, as late as possible at
534	runtime.	631	runtime.
535		632
		633	=item $guard = AnyEvent::post_detect { BLOCK }
		634
		635	Arranges for the code block to be executed as soon as the event model is
		636	autodetected (or immediately if this has already happened).
		637
		638	If called in scalar or list context, then it creates and returns an object
		639	that automatically removes the callback again when it is destroyed. See
		640	L<Coro::BDB> for a case where this is useful.
		641
		642	=item @AnyEvent::post_detect
		643
		644	If there are any code references in this array (you can C<push> to it
		645	before or after loading AnyEvent), then they will called directly after
		646	the event loop has been chosen.
		647
		648	You should check C<$AnyEvent::MODEL> before adding to this array, though:
		649	if it contains a true value then the event loop has already been detected,
		650	and the array will be ignored.
		651
		652	Best use C<AnyEvent::post_detect { BLOCK }> instead.
		653
536	=back	654	=back
537		655
538	=head1 WHAT TO DO IN A MODULE	656	=head1 WHAT TO DO IN A MODULE
539		657
540	As a module author, you should C<use AnyEvent> and call AnyEvent methods	658	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	661	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	662	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	663	by calling AnyEvent in your module body you force the user of your module
546	to load the event module first.	664	to load the event module first.
547		665
548	Never call C<< ->wait >> on a condition variable unless you I<know> that	666	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	667	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	668	because it will stall the whole program, and the whole point of using
551	events is to stay interactive.	669	events is to stay interactive.
552		670
553	It is fine, however, to call C<< ->wait >> when the user of your module	671	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	672	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 >>	673	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).	674	freely, as the user of your module knows what she is doing. always).
557		675
558	=head1 WHAT TO DO IN THE MAIN PROGRAM	676	=head1 WHAT TO DO IN THE MAIN PROGRAM
559		677
560	There will always be a single main program - the only place that should	678	There will always be a single main program - the only place that should
…		…
562		680
563	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	681	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	682	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.	683	decide which implementation to chose if some module relies on it.
566		684
567	If the main program relies on a specific event model. For example, in	685	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	686	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	687	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	688	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	689	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	690	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.	691	might chose the wrong one unless you load the correct one yourself.
574		692
575	You can chose to use a rather inefficient pure-perl implementation by	693	You can chose to use a pure-perl implementation by loading the
576	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	694	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
577	behaviour everywhere, but letting AnyEvent chose is generally better.	695	everywhere, but letting AnyEvent chose the model is generally better.
		696
		697	=head2 MAINLOOP EMULATION
		698
		699	Sometimes (often for short test scripts, or even standalone programs who
		700	only want to use AnyEvent), you do not want to run a specific event loop.
		701
		702	In that case, you can use a condition variable like this:
		703
		704	AnyEvent->condvar->recv;
		705
		706	This has the effect of entering the event loop and looping forever.
		707
		708	Note that usually your program has some exit condition, in which case
		709	it is better to use the "traditional" approach of storing a condition
		710	variable somewhere, waiting for it, and sending it when the program should
		711	exit cleanly.
		712
578		713
579	=head1 OTHER MODULES	714	=head1 OTHER MODULES
580		715
581	The following is a non-exhaustive list of additional modules that use	716	The following is a non-exhaustive list of additional modules that use
582	AnyEvent and can therefore be mixed easily with other AnyEvent modules	717	AnyEvent and can therefore be mixed easily with other AnyEvent modules
…		…
594		729
595	Provide read and write buffers and manages watchers for reads and writes.	730	Provide read and write buffers and manages watchers for reads and writes.
596		731
597	=item L<AnyEvent::Socket>	732	=item L<AnyEvent::Socket>
598		733
599	Provides a means to do non-blocking connects, accepts etc.	734	Provides various utility functions for (internet protocol) sockets,
		735	addresses and name resolution. Also functions to create non-blocking tcp
		736	connections or tcp servers, with IPv6 and SRV record support and more.
		737
		738	=item L<AnyEvent::DNS>
		739
		740	Provides rich asynchronous DNS resolver capabilities.
600		741
601	=item L<AnyEvent::HTTPD>	742	=item L<AnyEvent::HTTPD>
602		743
603	Provides a simple web application server framework.	744	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		745
610	=item L<AnyEvent::FastPing>	746	=item L<AnyEvent::FastPing>
611		747
612	The fastest ping in the west.	748	The fastest ping in the west.
613		749
…		…
628		764
629	High level API for event-based execution flow control.	765	High level API for event-based execution flow control.
630		766
631	=item L<Coro>	767	=item L<Coro>
632		768
633	Has special support for AnyEvent.	769	Has special support for AnyEvent via L<Coro::AnyEvent>.
		770
		771	=item L<AnyEvent::AIO>, L<IO::AIO>
		772
		773	Truly asynchronous I/O, should be in the toolbox of every event
		774	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
		775	together.
		776
		777	=item L<AnyEvent::BDB>, L<BDB>
		778
		779	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
		780	IO::AIO and AnyEvent together.
634		781
635	=item L<IO::Lambda>	782	=item L<IO::Lambda>
636		783
637	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	784	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		785
649	=back	786	=back
650		787
651	=cut	788	=cut
652		789
…		…
655	no warnings;	792	no warnings;
656	use strict;	793	use strict;
657		794
658	use Carp;	795	use Carp;
659		796
660	our $VERSION = '3.3';	797	our $VERSION = '4.05';
661	our $MODEL;	798	our $MODEL;
662		799
663	our $AUTOLOAD;	800	our $AUTOLOAD;
664	our @ISA;	801	our @ISA;
665		802
		803	our @REGISTRY;
		804
		805	our $WIN32;
		806
		807	BEGIN {
		808	my $win32 = ! ! ($^O =~ /mswin32/i);
		809	eval "sub WIN32(){ $win32 }";
		810	}
		811
666	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	812	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
667		813
668	our @REGISTRY;	814	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
		815
		816	{
		817	my $idx;
		818	$PROTOCOL{$_} = ++$idx
		819	for reverse split /\s,\s/,
		820	$ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
		821	}
669		822
670	my @models = (	823	my @models = (
671	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
672	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
673	[EV:: => AnyEvent::Impl::EV::],	824	[EV:: => AnyEvent::Impl::EV::],
674	[Event:: => AnyEvent::Impl::Event::],	825	[Event:: => AnyEvent::Impl::Event::],
675	[Tk:: => AnyEvent::Impl::Tk::],
676	[Wx:: => AnyEvent::Impl::POE::],
677	[Prima:: => AnyEvent::Impl::POE::],
678	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	826	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
679	# everything below here will not be autoprobed as the pureperl backend should work everywhere	827	# everything below here will not be autoprobed
680	[Glib:: => AnyEvent::Impl::Glib::],	828	# as the pureperl backend should work everywhere
		829	# and is usually faster
		830	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		831	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
681	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	832	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
682	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	833	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
683	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	834	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
		835	[Wx:: => AnyEvent::Impl::POE::],
		836	[Prima:: => AnyEvent::Impl::POE::],
684	);	837	);
685		838
686	our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY);	839	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
		840
		841	our @post_detect;
		842
		843	sub post_detect(&) {
		844	my ($cb) = @_;
		845
		846	if ($MODEL) {
		847	$cb->();
		848
		849	1
		850	} else {
		851	push @post_detect, $cb;
		852
		853	defined wantarray
		854	? bless \$cb, "AnyEvent::Util::PostDetect"
		855	: ()
		856	}
		857	}
		858
		859	sub AnyEvent::Util::PostDetect::DESTROY {
		860	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		861	}
687		862
688	sub detect() {	863	sub detect() {
689	unless ($MODEL) {	864	unless ($MODEL) {
690	no strict 'refs';	865	no strict 'refs';
		866	local $SIG{__DIE__};
691		867
692	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	868	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
693	my $model = "AnyEvent::Impl::$1";	869	my $model = "AnyEvent::Impl::$1";
694	if (eval "require $model") {	870	if (eval "require $model") {
695	$MODEL = $model;	871	$MODEL = $model;
…		…
725	last;	901	last;
726	}	902	}
727	}	903	}
728		904
729	$MODEL	905	$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.";	906	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
731	}	907	}
732	}	908	}
733		909
734	unshift @ISA, $MODEL;	910	unshift @ISA, $MODEL;
735	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	911	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		912
		913	(shift @post_detect)->() while @post_detect;
736	}	914	}
737		915
738	$MODEL	916	$MODEL
739	}	917	}
740		918
…		…
750	$class->$func (@_);	928	$class->$func (@_);
751	}	929	}
752		930
753	package AnyEvent::Base;	931	package AnyEvent::Base;
754		932
		933	# default implementation for now and time
		934
		935	use Time::HiRes ();
		936
		937	sub time { Time::HiRes::time }
		938	sub now { Time::HiRes::time }
		939
755	# default implementation for ->condvar, ->wait, ->broadcast	940	# default implementation for ->condvar
756		941
757	sub condvar {	942	sub condvar {
758	bless \my $flag, "AnyEvent::Base::CondVar"	943	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	}	944	}
768		945
769	# default implementation for ->signal	946	# default implementation for ->signal
770		947
771	our %SIG_CB;	948	our %SIG_CB;
…		…
824	or Carp::croak "required option 'pid' is missing";	1001	or Carp::croak "required option 'pid' is missing";
825		1002
826	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1003	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
827		1004
828	unless ($WNOHANG) {	1005	unless ($WNOHANG) {
829	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } \|\| 1;	1006	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
830	}	1007	}
831		1008
832	unless ($CHLD_W) {	1009	unless ($CHLD_W) {
833	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1010	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
834	# child could be a zombie already, so make at least one round	1011	# child could be a zombie already, so make at least one round
…		…
844	delete $PID_CB{$pid}{$cb};	1021	delete $PID_CB{$pid}{$cb};
845	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1022	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
846		1023
847	undef $CHLD_W unless keys %PID_CB;	1024	undef $CHLD_W unless keys %PID_CB;
848	}	1025	}
		1026
		1027	package AnyEvent::CondVar;
		1028
		1029	our @ISA = AnyEvent::CondVar::Base::;
		1030
		1031	package AnyEvent::CondVar::Base;
		1032
		1033	use overload
		1034	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		1035	fallback => 1;
		1036
		1037	sub _send {
		1038	# nop
		1039	}
		1040
		1041	sub send {
		1042	my $cv = shift;
		1043	$cv->{_ae_sent} = [@_];
		1044	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		1045	$cv->_send;
		1046	}
		1047
		1048	sub croak {
		1049	$_[0]{_ae_croak} = $_[1];
		1050	$_[0]->send;
		1051	}
		1052
		1053	sub ready {
		1054	$_[0]{_ae_sent}
		1055	}
		1056
		1057	sub _wait {
		1058	AnyEvent->one_event while !$_[0]{_ae_sent};
		1059	}
		1060
		1061	sub recv {
		1062	$_[0]->_wait;
		1063
		1064	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		1065	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		1066	}
		1067
		1068	sub cb {
		1069	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		1070	$_[0]{_ae_cb}
		1071	}
		1072
		1073	sub begin {
		1074	++$_[0]{_ae_counter};
		1075	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		1076	}
		1077
		1078	sub end {
		1079	return if --$_[0]{_ae_counter};
		1080	&{ $_[0]{_ae_end_cb} \|\| sub { $_[0]->send } };
		1081	}
		1082
		1083	# undocumented/compatibility with pre-3.4
		1084	*broadcast = \&send;
		1085	*wait = \&_wait;
849		1086
850	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1087	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
851		1088
852	This is an advanced topic that you do not normally need to use AnyEvent in	1089	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	1090	a module. This section is only of use to event loop authors who want to
…		…
910	model it chooses.	1147	model it chooses.
911		1148
912	=item C<PERL_ANYEVENT_MODEL>	1149	=item C<PERL_ANYEVENT_MODEL>
913		1150
914	This can be used to specify the event model to be used by AnyEvent, before	1151	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	1152	auto detection and -probing kicks in. It must be a string consisting
916	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1153	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,	1154	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	1155	used as event model. If it fails to load AnyEvent will proceed with
919	autodetection and -probing.	1156	auto detection and -probing.
920		1157
921	This functionality might change in future versions.	1158	This functionality might change in future versions.
922		1159
923	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1160	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
924	could start your program like this:	1161	could start your program like this:
925		1162
926	PERL_ANYEVENT_MODEL=Perl perl ...	1163	PERL_ANYEVENT_MODEL=Perl perl ...
		1164
		1165	=item C<PERL_ANYEVENT_PROTOCOLS>
		1166
		1167	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1168	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1169	of auto probing).
		1170
		1171	Must be set to a comma-separated list of protocols or address families,
		1172	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1173	used, and preference will be given to protocols mentioned earlier in the
		1174	list.
		1175
		1176	This variable can effectively be used for denial-of-service attacks
		1177	against local programs (e.g. when setuid), although the impact is likely
		1178	small, as the program has to handle connection errors already-
		1179
		1180	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1181	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1182	- only support IPv4, never try to resolve or contact IPv6
		1183	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1184	IPv6, but prefer IPv6 over IPv4.
		1185
		1186	=item C<PERL_ANYEVENT_EDNS0>
		1187
		1188	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1189	for DNS. This extension is generally useful to reduce DNS traffic, but
		1190	some (broken) firewalls drop such DNS packets, which is why it is off by
		1191	default.
		1192
		1193	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1194	EDNS0 in its DNS requests.
		1195
		1196	=item C<PERL_ANYEVENT_MAX_FORKS>
		1197
		1198	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1199	will create in parallel.
927		1200
928	=back	1201	=back
929		1202
930	=head1 EXAMPLE PROGRAM	1203	=head1 EXAMPLE PROGRAM
931		1204
…		…
942	poll => 'r',	1215	poll => 'r',
943	cb => sub {	1216	cb => sub {
944	warn "io event <$_[0]>\n"; # will always output <r>	1217	warn "io event <$_[0]>\n"; # will always output <r>
945	chomp (my $input = <STDIN>); # read a line	1218	chomp (my $input = <STDIN>); # read a line
946	warn "read: $input\n"; # output what has been read	1219	warn "read: $input\n"; # output what has been read
947	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1220	$cv->send if $input =~ /^q/i; # quit program if /^q/i
948	},	1221	},
949	);	1222	);
950		1223
951	my $time_watcher; # can only be used once	1224	my $time_watcher; # can only be used once
952		1225
…		…
957	});	1230	});
958	}	1231	}
959		1232
960	new_timer; # create first timer	1233	new_timer; # create first timer
961		1234
962	$cv->wait; # wait until user enters /^q/i	1235	$cv->recv; # wait until user enters /^q/i
963		1236
964	=head1 REAL-WORLD EXAMPLE	1237	=head1 REAL-WORLD EXAMPLE
965		1238
966	Consider the L<Net::FCP> module. It features (among others) the following	1239	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:	1240	API calls, which are to freenet what HTTP GET requests are to http:
…		…
1017	syswrite $txn->{fh}, $txn->{request}	1290	syswrite $txn->{fh}, $txn->{request}
1018	or die "connection or write error";	1291	or die "connection or write error";
1019	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1292	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1020		1293
1021	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1294	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:	1295	result and signals any possible waiters that the request has finished:
1023		1296
1024	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1297	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1025		1298
1026	if (end-of-file or data complete) {	1299	if (end-of-file or data complete) {
1027	$txn->{result} = $txn->{buf};	1300	$txn->{result} = $txn->{buf};
1028	$txn->{finished}->broadcast;	1301	$txn->{finished}->send;
1029	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1302	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
1030	}	1303	}
1031		1304
1032	The C<result> method, finally, just waits for the finished signal (if the	1305	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	1306	request was already finished, it doesn't wait, of course, and returns the
1034	data:	1307	data:
1035		1308
1036	$txn->{finished}->wait;	1309	$txn->{finished}->recv;
1037	return $txn->{result};	1310	return $txn->{result};
1038		1311
1039	The actual code goes further and collects all errors (C<die>s, exceptions)	1312	The actual code goes further and collects all errors (C<die>s, exceptions)
1040	that occured during request processing. The C<result> method detects	1313	that occurred during request processing. The C<result> method detects
1041	whether an exception as thrown (it is stored inside the $txn object)	1314	whether an exception as thrown (it is stored inside the $txn object)
1042	and just throws the exception, which means connection errors and other	1315	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	1316	problems get reported tot he code that tries to use the result, not in a
1044	random callback.	1317	random callback.
1045		1318
…		…
1076		1349
1077	my $quit = AnyEvent->condvar;	1350	my $quit = AnyEvent->condvar;
1078		1351
1079	$fcp->txn_client_get ($url)->cb (sub {	1352	$fcp->txn_client_get ($url)->cb (sub {
1080	...	1353	...
1081	$quit->broadcast;	1354	$quit->send;
1082	});	1355	});
1083		1356
1084	$quit->wait;	1357	$quit->recv;
1085		1358
1086		1359
1087	=head1 BENCHMARKS	1360	=head1 BENCHMARKS
1088		1361
1089	To give you an idea of the performance and overheads that AnyEvent adds	1362	To give you an idea of the performance and overheads that AnyEvent adds
…		…
1091	of various event loops I prepared some benchmarks.	1364	of various event loops I prepared some benchmarks.
1092		1365
1093	=head2 BENCHMARKING ANYEVENT OVERHEAD	1366	=head2 BENCHMARKING ANYEVENT OVERHEAD
1094		1367
1095	Here is a benchmark of various supported event models used natively and	1368	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	1369	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,	1370	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.	1371	which it is), lets them fire exactly once and destroys them again.
1099		1372
1100	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1373	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1101	distribution.	1374	distribution.
…		…
1118	all watchers, to avoid adding memory overhead. That means closure creation	1391	all watchers, to avoid adding memory overhead. That means closure creation
1119	and memory usage is not included in the figures.	1392	and memory usage is not included in the figures.
1120		1393
1121	I<invoke> is the time, in microseconds, used to invoke a simple	1394	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	1395	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	1396	invoked "watcher" times, it would C<< ->send >> a condvar once to
1124	signal the end of this phase.	1397	signal the end of this phase.
1125		1398
1126	I<destroy> is the time, in microseconds, that it takes to destroy a single	1399	I<destroy> is the time, in microseconds, that it takes to destroy a single
1127	watcher.	1400	watcher.
1128		1401
…		…
1224		1497
1225	=back	1498	=back
1226		1499
1227	=head2 BENCHMARKING THE LARGE SERVER CASE	1500	=head2 BENCHMARKING THE LARGE SERVER CASE
1228		1501
1229	This benchmark atcually benchmarks the event loop itself. It works by	1502	This benchmark actually benchmarks the event loop itself. It works by
1230	creating a number of "servers": each server consists of a socketpair, a	1503	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	1504	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	1505	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".	1506	watcher reads a byte it will write that byte to a random other "server".
1234		1507
1235	The effect is that there will be a lot of I/O watchers, only part of which	1508	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	1509	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	1510	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	1511	timeout is reset each time something is read because that reflects how
1239	most timeouts work (and puts extra pressure on the event loops).	1512	most timeouts work (and puts extra pressure on the event loops).
1240		1513
1241	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1514	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	1515	(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.	1516	connections, most of which are idle at any one point in time.
1244		1517
1245	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1518	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1246	distribution.	1519	distribution.
…		…
1248	=head3 Explanation of the columns	1521	=head3 Explanation of the columns
1249		1522
1250	I<sockets> is the number of sockets, and twice the number of "servers" (as	1523	I<sockets> is the number of sockets, and twice the number of "servers" (as
1251	each server has a read and write socket end).	1524	each server has a read and write socket end).
1252		1525
1253	I<create> is the time it takes to create a socketpair (which is	1526	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.	1527	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1255		1528
1256	I<request>, the most important value, is the time it takes to handle a	1529	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	1530	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	1531	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	1604	speed most when you have lots of watchers, not when you only have a few of
1332	them).	1605	them).
1333		1606
1334	EV is again fastest.	1607	EV is again fastest.
1335		1608
1336	Perl again comes second. It is noticably faster than the C-based event	1609	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	1610	loops Event and Glib, although the difference is too small to really
1338	matter.	1611	matter.
1339		1612
1340	POE also performs much better in this case, but is is still far behind the	1613	POE also performs much better in this case, but is is still far behind the
1341	others.	1614	others.
…		…
1374		1647
1375	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1648	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1376		1649
1377	use AnyEvent;	1650	use AnyEvent;
1378		1651
		1652	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
		1653	be used to probe what backend is used and gain other information (which is
		1654	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
		1655
1379		1656
1380	=head1 SEE ALSO	1657	=head1 SEE ALSO
1381		1658
1382	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,	1659	Utility functions: L<AnyEvent::Util>.
1383	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,	1660
		1661	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1384	L<Event::Lib>, L<Qt>, L<POE>.	1662	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1385		1663
1386	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,	1664	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1387	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,	1665	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>,	1666	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1389	L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>.	1667	L<AnyEvent::Impl::POE>.
1390		1668
		1669	Non-blocking file handles, sockets, TCP clients and
		1670	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1671
		1672	Asynchronous DNS: L<AnyEvent::DNS>.
		1673
		1674	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
		1675
1391	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1676	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1392		1677
1393		1678
1394	=head1 AUTHOR	1679	=head1 AUTHOR
1395		1680
1396	Marc Lehmann <schmorp@schmorp.de>	1681	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 1.143 by root, Wed May 28 23:57:38 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 1.143 by root, Wed May 28 23:57:38 2008 UTC