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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.109 by root, Sat May 10 00:45:18 2008 UTC vs.
Revision 1.165 by root, Tue Jul 8 23:07:26 2008 UTC

…		…
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 ->send	21	$w->recv; # enters "main loop" till $condvar gets ->send
21	$w->send; # wake up current and all future wait's	22
		23	=head1 INTRODUCTION/TUTORIAL
		24
		25	This manpage is mainly a reference manual. If you are interested
		26	in a tutorial or some gentle introduction, have a look at the
		27	L<AnyEvent::Intro> manpage.
22		28
23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	29	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24		30
25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	31	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26	nowadays. So what is different about AnyEvent?	32	nowadays. So what is different about AnyEvent?
…		…
48	isn't itself. What's worse, all the potential users of your module are	54	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.	55	I<also> forced to use the same event loop you use.
50		56
51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	57	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	58	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	59	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,	60	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	61	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	62	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	63	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).	64	event loops to AnyEvent, too, so it is future-proof).
59		65
60	In addition to being free of having to use I<the one and only true event	66	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	67	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	68	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	69	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	70	offering the functionality that is necessary, in as thin as a wrapper as
65	technically possible.	71	technically possible.
66		72
		73	Of course, AnyEvent comes with a big (and fully optional!) toolbox
		74	of useful functionality, such as an asynchronous DNS resolver, 100%
		75	non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
		76	such as Windows) and lots of real-world knowledge and workarounds for
		77	platform bugs and differences.
		78
67	Of course, if you want lots of policy (this can arguably be somewhat	79	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	80	useful) and you want to force your users to use the one and only event
69	model, you should I<not> use this module.	81	model, you should I<not> use this module.
70		82
71	=head1 DESCRIPTION	83	=head1 DESCRIPTION
72		84
…		…
102	starts using it, all bets are off. Maybe you should tell their authors to	114	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...	115	use AnyEvent so their modules work together with others seamlessly...
104		116
105	The pure-perl implementation of AnyEvent is called	117	The pure-perl implementation of AnyEvent is called
106	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	118	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
107	explicitly.	119	explicitly and enjoy the high availability of that event loop :)
108		120
109	=head1 WATCHERS	121	=head1 WATCHERS
110		122
111	AnyEvent has the central concept of a I<watcher>, which is an object that	123	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	124	stores relevant data for each kind of event you are waiting for, such as
113	the callback to call, the filehandle to watch, etc.	125	the callback to call, the file handle to watch, etc.
114		126
115	These watchers are normal Perl objects with normal Perl lifetime. After	127	These watchers are normal Perl objects with normal Perl lifetime. After
116	creating a watcher it will immediately "watch" for events and invoke the	128	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	129	callback when the event occurs (of course, only when the event model
118	is in control).	130	is in control).
…		…
126	Many watchers either are used with "recursion" (repeating timers for	138	Many watchers either are used with "recursion" (repeating timers for
127	example), or need to refer to their watcher object in other ways.	139	example), or need to refer to their watcher object in other ways.
128		140
129	An any way to achieve that is this pattern:	141	An any way to achieve that is this pattern:
130		142
131	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	143	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
132	# you can use $w here, for example to undef it	144	# you can use $w here, for example to undef it
133	undef $w;	145	undef $w;
134	});	146	});
135		147
136	Note that C<my $w; $w => combination. This is necessary because in Perl,	148	Note that C<my $w; $w => combination. This is necessary because in Perl,
137	my variables are only visible after the statement in which they are	149	my variables are only visible after the statement in which they are
138	declared.	150	declared.
139		151
…		…
158		170
159	Some event loops issue spurious readyness notifications, so you should	171	Some event loops issue spurious readyness notifications, so you should
160	always use non-blocking calls when reading/writing from/to your file	172	always use non-blocking calls when reading/writing from/to your file
161	handles.	173	handles.
162		174
163	Example:
164
165	# wait for readability of STDIN, then read a line and disable the watcher	175	Example: wait for readability of STDIN, then read a line and disable the
		176	watcher.
		177
166	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	178	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
167	chomp (my $input = <STDIN>);	179	chomp (my $input = <STDIN>);
168	warn "read: $input\n";	180	warn "read: $input\n";
169	undef $w;	181	undef $w;
170	});	182	});
…		…
180		192
181	Although the callback might get passed parameters, their value and	193	Although the callback might get passed parameters, their value and
182	presence is undefined and you cannot rely on them. Portable AnyEvent	194	presence is undefined and you cannot rely on them. Portable AnyEvent
183	callbacks cannot use arguments passed to time watcher callbacks.	195	callbacks cannot use arguments passed to time watcher callbacks.
184		196
185	The timer callback will be invoked at most once: if you want a repeating	197	The callback will normally be invoked once only. If you specify another
186	timer you have to create a new watcher (this is a limitation by both Tk	198	parameter, C<interval>, as a strictly positive number (> 0), then the
187	and Glib).	199	callback will be invoked regularly at that interval (in fractional
		200	seconds) after the first invocation. If C<interval> is specified with a
		201	false value, then it is treated as if it were missing.
188		202
189	Example:	203	The callback will be rescheduled before invoking the callback, but no
		204	attempt is done to avoid timer drift in most backends, so the interval is
		205	only approximate.
190		206
191	# fire an event after 7.7 seconds	207	Example: fire an event after 7.7 seconds.
		208
192	my $w = AnyEvent->timer (after => 7.7, cb => sub {	209	my $w = AnyEvent->timer (after => 7.7, cb => sub {
193	warn "timeout\n";	210	warn "timeout\n";
194	});	211	});
195		212
196	# to cancel the timer:	213	# to cancel the timer:
197	undef $w;	214	undef $w;
198		215
199	Example 2:
200
201	# fire an event after 0.5 seconds, then roughly every second	216	Example 2: fire an event after 0.5 seconds, then roughly every second.
202	my $w;
203		217
204	my $cb = sub {
205	# cancel the old timer while creating a new one
206	$w = AnyEvent->timer (after => 1, cb => $cb);	218	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		219	warn "timeout\n";
207	};	220	};
208
209	# start the "loop" by creating the first watcher
210	$w = AnyEvent->timer (after => 0.5, cb => $cb);
211		221
212	=head3 TIMING ISSUES	222	=head3 TIMING ISSUES
213		223
214	There are two ways to handle timers: based on real time (relative, "fire	224	There are two ways to handle timers: based on real time (relative, "fire
215	in 10 seconds") and based on wallclock time (absolute, "fire at 12	225	in 10 seconds") and based on wallclock time (absolute, "fire at 12
…		…
227	timers.	237	timers.
228		238
229	AnyEvent always prefers relative timers, if available, matching the	239	AnyEvent always prefers relative timers, if available, matching the
230	AnyEvent API.	240	AnyEvent API.
231		241
		242	AnyEvent has two additional methods that return the "current time":
		243
		244	=over 4
		245
		246	=item AnyEvent->time
		247
		248	This returns the "current wallclock time" as a fractional number of
		249	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
		250	return, and the result is guaranteed to be compatible with those).
		251
		252	It progresses independently of any event loop processing, i.e. each call
		253	will check the system clock, which usually gets updated frequently.
		254
		255	=item AnyEvent->now
		256
		257	This also returns the "current wallclock time", but unlike C<time>, above,
		258	this value might change only once per event loop iteration, depending on
		259	the event loop (most return the same time as C<time>, above). This is the
		260	time that AnyEvent's timers get scheduled against.
		261
		262	I<In almost all cases (in all cases if you don't care), this is the
		263	function to call when you want to know the current time.>
		264
		265	This function is also often faster then C<< AnyEvent->time >>, and
		266	thus the preferred method if you want some timestamp (for example,
		267	L<AnyEvent::Handle> uses this to update it's activity timeouts).
		268
		269	The rest of this section is only of relevance if you try to be very exact
		270	with your timing, you can skip it without bad conscience.
		271
		272	For a practical example of when these times differ, consider L<Event::Lib>
		273	and L<EV> and the following set-up:
		274
		275	The event loop is running and has just invoked one of your callback at
		276	time=500 (assume no other callbacks delay processing). In your callback,
		277	you wait a second by executing C<sleep 1> (blocking the process for a
		278	second) and then (at time=501) you create a relative timer that fires
		279	after three seconds.
		280
		281	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
		282	both return C<501>, because that is the current time, and the timer will
		283	be scheduled to fire at time=504 (C<501> + C<3>).
		284
		285	With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
		286	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
		287	last event processing phase started. With L<EV>, your timer gets scheduled
		288	to run at time=503 (C<500> + C<3>).
		289
		290	In one sense, L<Event::Lib> is more exact, as it uses the current time
		291	regardless of any delays introduced by event processing. However, most
		292	callbacks do not expect large delays in processing, so this causes a
		293	higher drift (and a lot more system calls to get the current time).
		294
		295	In another sense, L<EV> is more exact, as your timer will be scheduled at
		296	the same time, regardless of how long event processing actually took.
		297
		298	In either case, if you care (and in most cases, you don't), then you
		299	can get whatever behaviour you want with any event loop, by taking the
		300	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
		301	account.
		302
		303	=back
		304
232	=head2 SIGNAL WATCHERS	305	=head2 SIGNAL WATCHERS
233		306
234	You can watch for signals using a signal watcher, C<signal> is the signal	307	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	308	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to
236	be invoked whenever a signal occurs.	309	be invoked whenever a signal occurs.
237		310
238	Although the callback might get passed parameters, their value and	311	Although the callback might get passed parameters, their value and
239	presence is undefined and you cannot rely on them. Portable AnyEvent	312	presence is undefined and you cannot rely on them. Portable AnyEvent
240	callbacks cannot use arguments passed to signal watcher callbacks.	313	callbacks cannot use arguments passed to signal watcher callbacks.
241		314
242	Multiple signal occurances can be clumped together into one callback	315	Multiple signal occurrences can be clumped together into one callback
243	invocation, and callback invocation will be synchronous. synchronous means	316	invocation, and callback invocation will be synchronous. Synchronous means
244	that it might take a while until the signal gets handled by the process,	317	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.	318	but it is guaranteed not to interrupt any other callbacks.
246		319
247	The main advantage of using these watchers is that you can share a signal	320	The main advantage of using these watchers is that you can share a signal
248	between multiple watchers.	321	between multiple watchers.
249		322
250	This watcher might use C<%SIG>, so programs overwriting those signals	323	This watcher might use C<%SIG>, so programs overwriting those signals
…		…
277	AnyEvent program, you I<have> to create at least one watcher before you	350	AnyEvent program, you I<have> to create at least one watcher before you
278	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	351	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
279		352
280	Example: fork a process and wait for it	353	Example: fork a process and wait for it
281		354
282	my $done = AnyEvent->condvar;	355	my $done = AnyEvent->condvar;
283		356
284	AnyEvent::detect; # force event module to be initialised
285
286	my $pid = fork or exit 5;	357	my $pid = fork or exit 5;
287		358
288	my $w = AnyEvent->child (	359	my $w = AnyEvent->child (
289	pid => $pid,	360	pid => $pid,
290	cb => sub {	361	cb => sub {
291	my ($pid, $status) = @_;	362	my ($pid, $status) = @_;
292	warn "pid $pid exited with status $status";	363	warn "pid $pid exited with status $status";
293	$done->send;	364	$done->send;
294	},	365	},
295	);	366	);
296		367
297	# do something else, then wait for process exit	368	# do something else, then wait for process exit
298	$done->wait;	369	$done->recv;
299		370
300	=head2 CONDITION VARIABLES	371	=head2 CONDITION VARIABLES
301		372
302	If you are familiar with some event loops you will know that all of them	373	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	374	require you to run some blocking "loop", "run" or similar function that
…		…
312	Condition variables can be created by calling the C<< AnyEvent->condvar	383	Condition variables can be created by calling the C<< AnyEvent->condvar
313	>> method, usually without arguments. The only argument pair allowed is	384	>> method, usually without arguments. The only argument pair allowed is
314	C<cb>, which specifies a callback to be called when the condition variable	385	C<cb>, which specifies a callback to be called when the condition variable
315	becomes true.	386	becomes true.
316		387
317	After creation, the conditon variable is "false" until it becomes "true"	388	After creation, the condition variable is "false" until it becomes "true"
318	by calling the C<send> method.	389	by calling the C<send> method (or calling the condition variable as if it
		390	were a callback, read about the caveats in the description for the C<<
		391	->send >> method).
319		392
320	Condition variables are similar to callbacks, except that you can	393	Condition variables are similar to callbacks, except that you can
321	optionally wait for them. They can also be called merge points - points	394	optionally wait for them. They can also be called merge points - points
322	in time where multiple outstandign events have been processed. And yet	395	in time where multiple outstanding events have been processed. And yet
323	another way to call them is transations - each condition variable can be	396	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	397	used to represent a transaction, which finishes at some point and delivers
325	a result.	398	a result.
326		399
327	Condition variables are very useful to signal that something has finished,	400	Condition variables are very useful to signal that something has finished,
328	for example, if you write a module that does asynchronous http requests,	401	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	402	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	403	availability of results. The user can either act when the callback is
331	called or can synchronously C<< ->wait >> for the results.	404	called or can synchronously C<< ->recv >> for the results.
332		405
333	You can also use them to simulate traditional event loops - for example,	406	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	407	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	408	could C<< ->recv >> in your main program until the user clicks the Quit
336	button of your app, which would C<< ->send >> the "quit" event.	409	button of your app, which would C<< ->send >> the "quit" event.
337		410
338	Note that condition variables recurse into the event loop - if you have	411	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	412	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	413	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,	414	you should avoid making a blocking wait yourself, at least in callbacks,
342	as this asks for trouble.	415	as this asks for trouble.
343		416
344	Condition variables are represented by hash refs in perl, and the keys	417	Condition variables are represented by hash refs in perl, and the keys
…		…
349		422
350	There are two "sides" to a condition variable - the "producer side" which	423	There are two "sides" to a condition variable - the "producer side" which
351	eventually calls C<< -> send >>, and the "consumer side", which waits	424	eventually calls C<< -> send >>, and the "consumer side", which waits
352	for the send to occur.	425	for the send to occur.
353		426
354	Example:	427	Example: wait for a timer.
355		428
356	# wait till the result is ready	429	# wait till the result is ready
357	my $result_ready = AnyEvent->condvar;	430	my $result_ready = AnyEvent->condvar;
358		431
359	# do something such as adding a timer	432	# do something such as adding a timer
…		…
365	cb => sub { $result_ready->send },	438	cb => sub { $result_ready->send },
366	);	439	);
367		440
368	# this "blocks" (while handling events) till the callback	441	# this "blocks" (while handling events) till the callback
369	# calls send	442	# calls send
370	$result_ready->wait;	443	$result_ready->recv;
		444
		445	Example: wait for a timer, but take advantage of the fact that
		446	condition variables are also code references.
		447
		448	my $done = AnyEvent->condvar;
		449	my $delay = AnyEvent->timer (after => 5, cb => $done);
		450	$done->recv;
371		451
372	=head3 METHODS FOR PRODUCERS	452	=head3 METHODS FOR PRODUCERS
373		453
374	These methods should only be used by the producing side, i.e. the	454	These methods should only be used by the producing side, i.e. the
375	code/module that eventually sends the signal. Note that it is also	455	code/module that eventually sends the signal. Note that it is also
…		…
378		458
379	=over 4	459	=over 4
380		460
381	=item $cv->send (...)	461	=item $cv->send (...)
382		462
383	Flag the condition as ready - a running C<< ->wait >> and all further	463	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	464	calls to C<recv> will (eventually) return after this method has been
385	called. If nobody is waiting the send will be remembered.	465	called. If nobody is waiting the send will be remembered.
386		466
387	If a callback has been set on the condition variable, it is called	467	If a callback has been set on the condition variable, it is called
388	immediately from within send.	468	immediately from within send.
389		469
390	Any arguments passed to the C<send> call will be returned by all	470	Any arguments passed to the C<send> call will be returned by all
391	future C<< ->wait >> calls.	471	future C<< ->recv >> calls.
		472
		473	Condition variables are overloaded so one can call them directly
		474	(as a code reference). Calling them directly is the same as calling
		475	C<send>. Note, however, that many C-based event loops do not handle
		476	overloading, so as tempting as it may be, passing a condition variable
		477	instead of a callback does not work. Both the pure perl and EV loops
		478	support overloading, however, as well as all functions that use perl to
		479	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
		480	example).
392		481
393	=item $cv->croak ($error)	482	=item $cv->croak ($error)
394		483
395	Similar to send, but causes all call's wait C<< ->wait >> to invoke	484	Similar to send, but causes all call's to C<< ->recv >> to invoke
396	C<Carp::croak> with the given error message/object/scalar.	485	C<Carp::croak> with the given error message/object/scalar.
397		486
398	This can be used to signal any errors to the condition variable	487	This can be used to signal any errors to the condition variable
399	user/consumer.	488	user/consumer.
400		489
401	=item $cv->begin ([group callback])	490	=item $cv->begin ([group callback])
402		491
403	=item $cv->end	492	=item $cv->end
		493
		494	These two methods are EXPERIMENTAL and MIGHT CHANGE.
404		495
405	These two methods can be used to combine many transactions/events into	496	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	497	one. For example, a function that pings many hosts in parallel might want
407	to use a condition variable for the whole process.	498	to use a condition variable for the whole process.
408		499
…		…
443	doesn't execute once).	534	doesn't execute once).
444		535
445	This is the general pattern when you "fan out" into multiple subrequests:	536	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>	537	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	538	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>.	539	C<begin> and for each subrequest you finish, call C<end>.
449		540
450	=back	541	=back
451		542
452	=head3 METHODS FOR CONSUMERS	543	=head3 METHODS FOR CONSUMERS
453		544
454	These methods should only be used by the consuming side, i.e. the	545	These methods should only be used by the consuming side, i.e. the
455	code awaits the condition.	546	code awaits the condition.
456		547
457	=over 4	548	=over 4
458		549
459	=item $cv->wait	550	=item $cv->recv
460		551
461	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	552	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
462	>> methods have been called on c<$cv>, while servicing other watchers	553	>> methods have been called on c<$cv>, while servicing other watchers
463	normally.	554	normally.
464		555
…		…
475	(programs might want to do that to stay interactive), so I<if you are	566	(programs might want to do that to stay interactive), so I<if you are
476	using this from a module, never require a blocking wait>, but let the	567	using this from a module, never require a blocking wait>, but let the
477	caller decide whether the call will block or not (for example, by coupling	568	caller decide whether the call will block or not (for example, by coupling
478	condition variables with some kind of request results and supporting	569	condition variables with some kind of request results and supporting
479	callbacks so the caller knows that getting the result will not block,	570	callbacks so the caller knows that getting the result will not block,
480	while still suppporting blocking waits if the caller so desires).	571	while still supporting blocking waits if the caller so desires).
481		572
482	Another reason I<never> to C<< ->wait >> in a module is that you cannot	573	Another reason I<never> to C<< ->recv >> in a module is that you cannot
483	sensibly have two C<< ->wait >>'s in parallel, as that would require	574	sensibly have two C<< ->recv >>'s in parallel, as that would require
484	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	575	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
485	can supply.	576	can supply.
486		577
487	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in	578	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	579	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
489	versions and also integrates coroutines into AnyEvent, making blocking	580	versions and also integrates coroutines into AnyEvent, making blocking
490	C<< ->wait >> calls perfectly safe as long as they are done from another	581	C<< ->recv >> calls perfectly safe as long as they are done from another
491	coroutine (one that doesn't run the event loop).	582	coroutine (one that doesn't run the event loop).
492		583
493	You can ensure that C<< -wait >> never blocks by setting a callback and	584	You can ensure that C<< -recv >> never blocks by setting a callback and
494	only calling C<< ->wait >> from within that callback (or at a later	585	only calling C<< ->recv >> from within that callback (or at a later
495	time). This will work even when the event loop does not support blocking	586	time). This will work even when the event loop does not support blocking
496	waits otherwise.	587	waits otherwise.
497		588
498	=item $bool = $cv->ready	589	=item $bool = $cv->ready
499		590
…		…
504		595
505	This is a mutator function that returns the callback set and optionally	596	This is a mutator function that returns the callback set and optionally
506	replaces it before doing so.	597	replaces it before doing so.
507		598
508	The callback will be called when the condition becomes "true", i.e. when	599	The callback will be called when the condition becomes "true", i.e. when
509	C<send> or C<croak> are called. Calling C<wait> inside the callback	600	C<send> or C<croak> are called, with the only argument being the condition
510	or at any later time is guaranteed not to block.	601	variable itself. Calling C<recv> inside the callback or at any later time
		602	is guaranteed not to block.
511		603
512	=back	604	=back
513		605
514	=head1 GLOBAL VARIABLES AND FUNCTIONS	606	=head1 GLOBAL VARIABLES AND FUNCTIONS
515		607
…		…
549	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	641	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
550	if necessary. You should only call this function right before you would	642	if necessary. You should only call this function right before you would
551	have created an AnyEvent watcher anyway, that is, as late as possible at	643	have created an AnyEvent watcher anyway, that is, as late as possible at
552	runtime.	644	runtime.
553		645
554	=item AnyEvent::on_detect { BLOCK }	646	=item $guard = AnyEvent::post_detect { BLOCK }
555		647
556	Arranges for the code block to be executed as soon as the event model is	648	Arranges for the code block to be executed as soon as the event model is
557	autodetected (or immediately if this has already happened).	649	autodetected (or immediately if this has already happened).
558		650
		651	If called in scalar or list context, then it creates and returns an object
		652	that automatically removes the callback again when it is destroyed. See
		653	L<Coro::BDB> for a case where this is useful.
		654
559	=item @AnyEvent::on_detect	655	=item @AnyEvent::post_detect
560		656
561	If there are any code references in this array (you can C<push> to it	657	If there are any code references in this array (you can C<push> to it
562	before or after loading AnyEvent), then they will called directly after	658	before or after loading AnyEvent), then they will called directly after
563	the event loop has been chosen.	659	the event loop has been chosen.
564		660
565	You should check C<$AnyEvent::MODEL> before adding to this array, though:	661	You should check C<$AnyEvent::MODEL> before adding to this array, though:
566	if it contains a true value then the event loop has already been detected,	662	if it contains a true value then the event loop has already been detected,
567	and the array will be ignored.	663	and the array will be ignored.
568		664
569	Best use C<AnyEvent::on_detect { BLOCK }> instead.	665	Best use C<AnyEvent::post_detect { BLOCK }> instead.
570		666
571	=back	667	=back
572		668
573	=head1 WHAT TO DO IN A MODULE	669	=head1 WHAT TO DO IN A MODULE
574		670
…		…
578	Be careful when you create watchers in the module body - AnyEvent will	674	Be careful when you create watchers in the module body - AnyEvent will
579	decide which event module to use as soon as the first method is called, so	675	decide which event module to use as soon as the first method is called, so
580	by calling AnyEvent in your module body you force the user of your module	676	by calling AnyEvent in your module body you force the user of your module
581	to load the event module first.	677	to load the event module first.
582		678
583	Never call C<< ->wait >> on a condition variable unless you I<know> that	679	Never call C<< ->recv >> on a condition variable unless you I<know> that
584	the C<< ->send >> method has been called on it already. This is	680	the C<< ->send >> method has been called on it already. This is
585	because it will stall the whole program, and the whole point of using	681	because it will stall the whole program, and the whole point of using
586	events is to stay interactive.	682	events is to stay interactive.
587		683
588	It is fine, however, to call C<< ->wait >> when the user of your module	684	It is fine, however, to call C<< ->recv >> when the user of your module
589	requests it (i.e. if you create a http request object ad have a method	685	requests it (i.e. if you create a http request object ad have a method
590	called C<results> that returns the results, it should call C<< ->wait >>	686	called C<results> that returns the results, it should call C<< ->recv >>
591	freely, as the user of your module knows what she is doing. always).	687	freely, as the user of your module knows what she is doing. always).
592		688
593	=head1 WHAT TO DO IN THE MAIN PROGRAM	689	=head1 WHAT TO DO IN THE MAIN PROGRAM
594		690
595	There will always be a single main program - the only place that should	691	There will always be a single main program - the only place that should
…		…
597		693
598	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	694	If it doesn't care, it can just "use AnyEvent" and use it itself, or not
599	do anything special (it does not need to be event-based) and let AnyEvent	695	do anything special (it does not need to be event-based) and let AnyEvent
600	decide which implementation to chose if some module relies on it.	696	decide which implementation to chose if some module relies on it.
601		697
602	If the main program relies on a specific event model. For example, in	698	If the main program relies on a specific event model - for example, in
603	Gtk2 programs you have to rely on the Glib module. You should load the	699	Gtk2 programs you have to rely on the Glib module - you should load the
604	event module before loading AnyEvent or any module that uses it: generally	700	event module before loading AnyEvent or any module that uses it: generally
605	speaking, you should load it as early as possible. The reason is that	701	speaking, you should load it as early as possible. The reason is that
606	modules might create watchers when they are loaded, and AnyEvent will	702	modules might create watchers when they are loaded, and AnyEvent will
607	decide on the event model to use as soon as it creates watchers, and it	703	decide on the event model to use as soon as it creates watchers, and it
608	might chose the wrong one unless you load the correct one yourself.	704	might chose the wrong one unless you load the correct one yourself.
609		705
610	You can chose to use a rather inefficient pure-perl implementation by	706	You can chose to use a pure-perl implementation by loading the
611	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	707	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
612	behaviour everywhere, but letting AnyEvent chose is generally better.	708	everywhere, but letting AnyEvent chose the model is generally better.
		709
		710	=head2 MAINLOOP EMULATION
		711
		712	Sometimes (often for short test scripts, or even standalone programs who
		713	only want to use AnyEvent), you do not want to run a specific event loop.
		714
		715	In that case, you can use a condition variable like this:
		716
		717	AnyEvent->condvar->recv;
		718
		719	This has the effect of entering the event loop and looping forever.
		720
		721	Note that usually your program has some exit condition, in which case
		722	it is better to use the "traditional" approach of storing a condition
		723	variable somewhere, waiting for it, and sending it when the program should
		724	exit cleanly.
		725
613		726
614	=head1 OTHER MODULES	727	=head1 OTHER MODULES
615		728
616	The following is a non-exhaustive list of additional modules that use	729	The following is a non-exhaustive list of additional modules that use
617	AnyEvent and can therefore be mixed easily with other AnyEvent modules	730	AnyEvent and can therefore be mixed easily with other AnyEvent modules
…		…
623	=item L<AnyEvent::Util>	736	=item L<AnyEvent::Util>
624		737
625	Contains various utility functions that replace often-used but blocking	738	Contains various utility functions that replace often-used but blocking
626	functions such as C<inet_aton> by event-/callback-based versions.	739	functions such as C<inet_aton> by event-/callback-based versions.
627		740
		741	=item L<AnyEvent::Socket>
		742
		743	Provides various utility functions for (internet protocol) sockets,
		744	addresses and name resolution. Also functions to create non-blocking tcp
		745	connections or tcp servers, with IPv6 and SRV record support and more.
		746
628	=item L<AnyEvent::Handle>	747	=item L<AnyEvent::Handle>
629		748
630	Provide read and write buffers and manages watchers for reads and writes.	749	Provide read and write buffers, manages watchers for reads and writes,
		750	supports raw and formatted I/O, I/O queued and fully transparent and
		751	non-blocking SSL/TLS.
631		752
632	=item L<AnyEvent::Socket>	753	=item L<AnyEvent::DNS>
633		754
634	Provides a means to do non-blocking connects, accepts etc.	755	Provides rich asynchronous DNS resolver capabilities.
		756
		757	=item L<AnyEvent::HTTP>
		758
		759	A simple-to-use HTTP library that is capable of making a lot of concurrent
		760	HTTP requests.
635		761
636	=item L<AnyEvent::HTTPD>	762	=item L<AnyEvent::HTTPD>
637		763
638	Provides a simple web application server framework.	764	Provides a simple web application server framework.
639		765
640	=item L<AnyEvent::DNS>
641
642	Provides asynchronous DNS resolver capabilities, beyond what
643	L<AnyEvent::Util> offers.
644
645	=item L<AnyEvent::FastPing>	766	=item L<AnyEvent::FastPing>
646		767
647	The fastest ping in the west.	768	The fastest ping in the west.
		769
		770	=item L<AnyEvent::DBI>
		771
		772	Executes L<DBI> requests asynchronously in a proxy process.
		773
		774	=item L<AnyEvent::AIO>
		775
		776	Truly asynchronous I/O, should be in the toolbox of every event
		777	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		778	together.
		779
		780	=item L<AnyEvent::BDB>
		781
		782	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		783	L<BDB> and AnyEvent together.
		784
		785	=item L<AnyEvent::GPSD>
		786
		787	A non-blocking interface to gpsd, a daemon delivering GPS information.
		788
		789	=item L<AnyEvent::IGS>
		790
		791	A non-blocking interface to the Internet Go Server protocol (used by
		792	L<App::IGS>).
648		793
649	=item L<Net::IRC3>	794	=item L<Net::IRC3>
650		795
651	AnyEvent based IRC client module family.	796	AnyEvent based IRC client module family.
652		797
…		…
669		814
670	=item L<IO::Lambda>	815	=item L<IO::Lambda>
671		816
672	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	817	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
673		818
674	=item L<IO::AIO>
675
676	Truly asynchronous I/O, should be in the toolbox of every event
677	programmer. Can be trivially made to use AnyEvent.
678
679	=item L<BDB>
680
681	Truly asynchronous Berkeley DB access. Can be trivially made to use
682	AnyEvent.
683
684	=back	819	=back
685		820
686	=cut	821	=cut
687		822
688	package AnyEvent;	823	package AnyEvent;
…		…
690	no warnings;	825	no warnings;
691	use strict;	826	use strict;
692		827
693	use Carp;	828	use Carp;
694		829
695	our $VERSION = '3.4';	830	our $VERSION = 4.2;
696	our $MODEL;	831	our $MODEL;
697		832
698	our $AUTOLOAD;	833	our $AUTOLOAD;
699	our @ISA;	834	our @ISA;
700		835
		836	our @REGISTRY;
		837
		838	our $WIN32;
		839
		840	BEGIN {
		841	my $win32 = ! ! ($^O =~ /mswin32/i);
		842	eval "sub WIN32(){ $win32 }";
		843	}
		844
701	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	845	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
702		846
703	our @REGISTRY;	847	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
		848
		849	{
		850	my $idx;
		851	$PROTOCOL{$_} = ++$idx
		852	for reverse split /\s,\s/,
		853	$ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
		854	}
704		855
705	my @models = (	856	my @models = (
706	[EV:: => AnyEvent::Impl::EV::],	857	[EV:: => AnyEvent::Impl::EV::],
707	[Event:: => AnyEvent::Impl::Event::],	858	[Event:: => AnyEvent::Impl::Event::],
708	[Tk:: => AnyEvent::Impl::Tk::],
709	[Wx:: => AnyEvent::Impl::POE::],
710	[Prima:: => AnyEvent::Impl::POE::],
711	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	859	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
712	# everything below here will not be autoprobed as the pureperl backend should work everywhere	860	# everything below here will not be autoprobed
713	[Glib:: => AnyEvent::Impl::Glib::],	861	# as the pureperl backend should work everywhere
		862	# and is usually faster
		863	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		864	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
714	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	865	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
715	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	866	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
716	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	867	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
		868	[Wx:: => AnyEvent::Impl::POE::],
		869	[Prima:: => AnyEvent::Impl::POE::],
717	);	870	);
718		871
719	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);	872	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
720		873
721	our @on_detect;	874	our @post_detect;
722		875
723	sub on_detect(&) {	876	sub post_detect(&) {
		877	my ($cb) = @_;
		878
724	if ($MODEL) {	879	if ($MODEL) {
725	$_[0]->();	880	$cb->();
		881
		882	1
726	} else {	883	} else {
727	push @on_detect, $_[0];	884	push @post_detect, $cb;
		885
		886	defined wantarray
		887	? bless \$cb, "AnyEvent::Util::PostDetect"
		888	: ()
728	}	889	}
		890	}
		891
		892	sub AnyEvent::Util::PostDetect::DESTROY {
		893	@post_detect = grep $_ != ${$_[0]}, @post_detect;
729	}	894	}
730		895
731	sub detect() {	896	sub detect() {
732	unless ($MODEL) {	897	unless ($MODEL) {
733	no strict 'refs';	898	no strict 'refs';
		899	local $SIG{__DIE__};
734		900
735	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	901	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
736	my $model = "AnyEvent::Impl::$1";	902	my $model = "AnyEvent::Impl::$1";
737	if (eval "require $model") {	903	if (eval "require $model") {
738	$MODEL = $model;	904	$MODEL = $model;
…		…
775	}	941	}
776		942
777	unshift @ISA, $MODEL;	943	unshift @ISA, $MODEL;
778	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	944	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
779		945
780	(shift @on_detect)->() while @on_detect;	946	(shift @post_detect)->() while @post_detect;
781	}	947	}
782		948
783	$MODEL	949	$MODEL
784	}	950	}
785		951
…		…
795	$class->$func (@_);	961	$class->$func (@_);
796	}	962	}
797		963
798	package AnyEvent::Base;	964	package AnyEvent::Base;
799		965
		966	# default implementation for now and time
		967
		968	use Time::HiRes ();
		969
		970	sub time { Time::HiRes::time }
		971	sub now { Time::HiRes::time }
		972
800	# default implementation for ->condvar, ->wait, ->broadcast	973	# default implementation for ->condvar
801		974
802	sub condvar {	975	sub condvar {
803	bless \my $flag, "AnyEvent::Base::CondVar"	976	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
804	}
805
806	sub AnyEvent::Base::CondVar::broadcast {
807	${$_[0]}++;
808	}
809
810	sub AnyEvent::Base::CondVar::wait {
811	AnyEvent->one_event while !${$_[0]};
812	}	977	}
813		978
814	# default implementation for ->signal	979	# default implementation for ->signal
815		980
816	our %SIG_CB;	981	our %SIG_CB;
…		…
832	sub AnyEvent::Base::Signal::DESTROY {	997	sub AnyEvent::Base::Signal::DESTROY {
833	my ($signal, $cb) = @{$_[0]};	998	my ($signal, $cb) = @{$_[0]};
834		999
835	delete $SIG_CB{$signal}{$cb};	1000	delete $SIG_CB{$signal}{$cb};
836		1001
837	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1002	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
838	}	1003	}
839		1004
840	# default implementation for ->child	1005	# default implementation for ->child
841		1006
842	our %PID_CB;	1007	our %PID_CB;
…		…
869	or Carp::croak "required option 'pid' is missing";	1034	or Carp::croak "required option 'pid' is missing";
870		1035
871	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1036	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
872		1037
873	unless ($WNOHANG) {	1038	unless ($WNOHANG) {
874	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } \|\| 1;	1039	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
875	}	1040	}
876		1041
877	unless ($CHLD_W) {	1042	unless ($CHLD_W) {
878	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1043	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
879	# child could be a zombie already, so make at least one round	1044	# child could be a zombie already, so make at least one round
…		…
889	delete $PID_CB{$pid}{$cb};	1054	delete $PID_CB{$pid}{$cb};
890	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1055	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
891		1056
892	undef $CHLD_W unless keys %PID_CB;	1057	undef $CHLD_W unless keys %PID_CB;
893	}	1058	}
		1059
		1060	package AnyEvent::CondVar;
		1061
		1062	our @ISA = AnyEvent::CondVar::Base::;
		1063
		1064	package AnyEvent::CondVar::Base;
		1065
		1066	use overload
		1067	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		1068	fallback => 1;
		1069
		1070	sub _send {
		1071	# nop
		1072	}
		1073
		1074	sub send {
		1075	my $cv = shift;
		1076	$cv->{_ae_sent} = [@_];
		1077	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		1078	$cv->_send;
		1079	}
		1080
		1081	sub croak {
		1082	$_[0]{_ae_croak} = $_[1];
		1083	$_[0]->send;
		1084	}
		1085
		1086	sub ready {
		1087	$_[0]{_ae_sent}
		1088	}
		1089
		1090	sub _wait {
		1091	AnyEvent->one_event while !$_[0]{_ae_sent};
		1092	}
		1093
		1094	sub recv {
		1095	$_[0]->_wait;
		1096
		1097	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		1098	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		1099	}
		1100
		1101	sub cb {
		1102	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		1103	$_[0]{_ae_cb}
		1104	}
		1105
		1106	sub begin {
		1107	++$_[0]{_ae_counter};
		1108	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		1109	}
		1110
		1111	sub end {
		1112	return if --$_[0]{_ae_counter};
		1113	&{ $_[0]{_ae_end_cb} \|\| sub { $_[0]->send } };
		1114	}
		1115
		1116	# undocumented/compatibility with pre-3.4
		1117	*broadcast = \&send;
		1118	*wait = \&_wait;
894		1119
895	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1120	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
896		1121
897	This is an advanced topic that you do not normally need to use AnyEvent in	1122	This is an advanced topic that you do not normally need to use AnyEvent in
898	a module. This section is only of use to event loop authors who want to	1123	a module. This section is only of use to event loop authors who want to
…		…
955	model it chooses.	1180	model it chooses.
956		1181
957	=item C<PERL_ANYEVENT_MODEL>	1182	=item C<PERL_ANYEVENT_MODEL>
958		1183
959	This can be used to specify the event model to be used by AnyEvent, before	1184	This can be used to specify the event model to be used by AnyEvent, before
960	autodetection and -probing kicks in. It must be a string consisting	1185	auto detection and -probing kicks in. It must be a string consisting
961	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1186	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
962	and the resulting module name is loaded and if the load was successful,	1187	and the resulting module name is loaded and if the load was successful,
963	used as event model. If it fails to load AnyEvent will proceed with	1188	used as event model. If it fails to load AnyEvent will proceed with
964	autodetection and -probing.	1189	auto detection and -probing.
965		1190
966	This functionality might change in future versions.	1191	This functionality might change in future versions.
967		1192
968	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1193	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
969	could start your program like this:	1194	could start your program like this:
970		1195
971	PERL_ANYEVENT_MODEL=Perl perl ...	1196	PERL_ANYEVENT_MODEL=Perl perl ...
		1197
		1198	=item C<PERL_ANYEVENT_PROTOCOLS>
		1199
		1200	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1201	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1202	of auto probing).
		1203
		1204	Must be set to a comma-separated list of protocols or address families,
		1205	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1206	used, and preference will be given to protocols mentioned earlier in the
		1207	list.
		1208
		1209	This variable can effectively be used for denial-of-service attacks
		1210	against local programs (e.g. when setuid), although the impact is likely
		1211	small, as the program has to handle connection errors already-
		1212
		1213	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1214	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1215	- only support IPv4, never try to resolve or contact IPv6
		1216	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1217	IPv6, but prefer IPv6 over IPv4.
		1218
		1219	=item C<PERL_ANYEVENT_EDNS0>
		1220
		1221	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1222	for DNS. This extension is generally useful to reduce DNS traffic, but
		1223	some (broken) firewalls drop such DNS packets, which is why it is off by
		1224	default.
		1225
		1226	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1227	EDNS0 in its DNS requests.
		1228
		1229	=item C<PERL_ANYEVENT_MAX_FORKS>
		1230
		1231	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1232	will create in parallel.
972		1233
973	=back	1234	=back
974		1235
975	=head1 EXAMPLE PROGRAM	1236	=head1 EXAMPLE PROGRAM
976		1237
…		…
987	poll => 'r',	1248	poll => 'r',
988	cb => sub {	1249	cb => sub {
989	warn "io event <$_[0]>\n"; # will always output <r>	1250	warn "io event <$_[0]>\n"; # will always output <r>
990	chomp (my $input = <STDIN>); # read a line	1251	chomp (my $input = <STDIN>); # read a line
991	warn "read: $input\n"; # output what has been read	1252	warn "read: $input\n"; # output what has been read
992	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1253	$cv->send if $input =~ /^q/i; # quit program if /^q/i
993	},	1254	},
994	);	1255	);
995		1256
996	my $time_watcher; # can only be used once	1257	my $time_watcher; # can only be used once
997		1258
…		…
1002	});	1263	});
1003	}	1264	}
1004		1265
1005	new_timer; # create first timer	1266	new_timer; # create first timer
1006		1267
1007	$cv->wait; # wait until user enters /^q/i	1268	$cv->recv; # wait until user enters /^q/i
1008		1269
1009	=head1 REAL-WORLD EXAMPLE	1270	=head1 REAL-WORLD EXAMPLE
1010		1271
1011	Consider the L<Net::FCP> module. It features (among others) the following	1272	Consider the L<Net::FCP> module. It features (among others) the following
1012	API calls, which are to freenet what HTTP GET requests are to http:	1273	API calls, which are to freenet what HTTP GET requests are to http:
…		…
1062	syswrite $txn->{fh}, $txn->{request}	1323	syswrite $txn->{fh}, $txn->{request}
1063	or die "connection or write error";	1324	or die "connection or write error";
1064	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1325	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1065		1326
1066	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1327	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
1067	result and signals any possible waiters that the request ahs finished:	1328	result and signals any possible waiters that the request has finished:
1068		1329
1069	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1330	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1070		1331
1071	if (end-of-file or data complete) {	1332	if (end-of-file or data complete) {
1072	$txn->{result} = $txn->{buf};	1333	$txn->{result} = $txn->{buf};
1073	$txn->{finished}->broadcast;	1334	$txn->{finished}->send;
1074	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1335	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
1075	}	1336	}
1076		1337
1077	The C<result> method, finally, just waits for the finished signal (if the	1338	The C<result> method, finally, just waits for the finished signal (if the
1078	request was already finished, it doesn't wait, of course, and returns the	1339	request was already finished, it doesn't wait, of course, and returns the
1079	data:	1340	data:
1080		1341
1081	$txn->{finished}->wait;	1342	$txn->{finished}->recv;
1082	return $txn->{result};	1343	return $txn->{result};
1083		1344
1084	The actual code goes further and collects all errors (C<die>s, exceptions)	1345	The actual code goes further and collects all errors (C<die>s, exceptions)
1085	that occured during request processing. The C<result> method detects	1346	that occurred during request processing. The C<result> method detects
1086	whether an exception as thrown (it is stored inside the $txn object)	1347	whether an exception as thrown (it is stored inside the $txn object)
1087	and just throws the exception, which means connection errors and other	1348	and just throws the exception, which means connection errors and other
1088	problems get reported tot he code that tries to use the result, not in a	1349	problems get reported tot he code that tries to use the result, not in a
1089	random callback.	1350	random callback.
1090		1351
…		…
1121		1382
1122	my $quit = AnyEvent->condvar;	1383	my $quit = AnyEvent->condvar;
1123		1384
1124	$fcp->txn_client_get ($url)->cb (sub {	1385	$fcp->txn_client_get ($url)->cb (sub {
1125	...	1386	...
1126	$quit->broadcast;	1387	$quit->send;
1127	});	1388	});
1128		1389
1129	$quit->wait;	1390	$quit->recv;
1130		1391
1131		1392
1132	=head1 BENCHMARKS	1393	=head1 BENCHMARKS
1133		1394
1134	To give you an idea of the performance and overheads that AnyEvent adds	1395	To give you an idea of the performance and overheads that AnyEvent adds
…		…
1136	of various event loops I prepared some benchmarks.	1397	of various event loops I prepared some benchmarks.
1137		1398
1138	=head2 BENCHMARKING ANYEVENT OVERHEAD	1399	=head2 BENCHMARKING ANYEVENT OVERHEAD
1139		1400
1140	Here is a benchmark of various supported event models used natively and	1401	Here is a benchmark of various supported event models used natively and
1141	through anyevent. The benchmark creates a lot of timers (with a zero	1402	through AnyEvent. The benchmark creates a lot of timers (with a zero
1142	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	1403	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1143	which it is), lets them fire exactly once and destroys them again.	1404	which it is), lets them fire exactly once and destroys them again.
1144		1405
1145	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1406	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1146	distribution.	1407	distribution.
…		…
1163	all watchers, to avoid adding memory overhead. That means closure creation	1424	all watchers, to avoid adding memory overhead. That means closure creation
1164	and memory usage is not included in the figures.	1425	and memory usage is not included in the figures.
1165		1426
1166	I<invoke> is the time, in microseconds, used to invoke a simple	1427	I<invoke> is the time, in microseconds, used to invoke a simple
1167	callback. The callback simply counts down a Perl variable and after it was	1428	callback. The callback simply counts down a Perl variable and after it was
1168	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1429	invoked "watcher" times, it would C<< ->send >> a condvar once to
1169	signal the end of this phase.	1430	signal the end of this phase.
1170		1431
1171	I<destroy> is the time, in microseconds, that it takes to destroy a single	1432	I<destroy> is the time, in microseconds, that it takes to destroy a single
1172	watcher.	1433	watcher.
1173		1434
…		…
1269		1530
1270	=back	1531	=back
1271		1532
1272	=head2 BENCHMARKING THE LARGE SERVER CASE	1533	=head2 BENCHMARKING THE LARGE SERVER CASE
1273		1534
1274	This benchmark atcually benchmarks the event loop itself. It works by	1535	This benchmark actually benchmarks the event loop itself. It works by
1275	creating a number of "servers": each server consists of a socketpair, a	1536	creating a number of "servers": each server consists of a socket pair, a
1276	timeout watcher that gets reset on activity (but never fires), and an I/O	1537	timeout watcher that gets reset on activity (but never fires), and an I/O
1277	watcher waiting for input on one side of the socket. Each time the socket	1538	watcher waiting for input on one side of the socket. Each time the socket
1278	watcher reads a byte it will write that byte to a random other "server".	1539	watcher reads a byte it will write that byte to a random other "server".
1279		1540
1280	The effect is that there will be a lot of I/O watchers, only part of which	1541	The effect is that there will be a lot of I/O watchers, only part of which
1281	are active at any one point (so there is a constant number of active	1542	are active at any one point (so there is a constant number of active
1282	fds for each loop iterstaion, but which fds these are is random). The	1543	fds for each loop iteration, but which fds these are is random). The
1283	timeout is reset each time something is read because that reflects how	1544	timeout is reset each time something is read because that reflects how
1284	most timeouts work (and puts extra pressure on the event loops).	1545	most timeouts work (and puts extra pressure on the event loops).
1285		1546
1286	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1547	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1287	(1%) are active. This mirrors the activity of large servers with many	1548	(1%) are active. This mirrors the activity of large servers with many
1288	connections, most of which are idle at any one point in time.	1549	connections, most of which are idle at any one point in time.
1289		1550
1290	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1551	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1291	distribution.	1552	distribution.
…		…
1293	=head3 Explanation of the columns	1554	=head3 Explanation of the columns
1294		1555
1295	I<sockets> is the number of sockets, and twice the number of "servers" (as	1556	I<sockets> is the number of sockets, and twice the number of "servers" (as
1296	each server has a read and write socket end).	1557	each server has a read and write socket end).
1297		1558
1298	I<create> is the time it takes to create a socketpair (which is	1559	I<create> is the time it takes to create a socket pair (which is
1299	nontrivial) and two watchers: an I/O watcher and a timeout watcher.	1560	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1300		1561
1301	I<request>, the most important value, is the time it takes to handle a	1562	I<request>, the most important value, is the time it takes to handle a
1302	single "request", that is, reading the token from the pipe and forwarding	1563	single "request", that is, reading the token from the pipe and forwarding
1303	it to another server. This includes deleting the old timeout and creating	1564	it to another server. This includes deleting the old timeout and creating
…		…
1376	speed most when you have lots of watchers, not when you only have a few of	1637	speed most when you have lots of watchers, not when you only have a few of
1377	them).	1638	them).
1378		1639
1379	EV is again fastest.	1640	EV is again fastest.
1380		1641
1381	Perl again comes second. It is noticably faster than the C-based event	1642	Perl again comes second. It is noticeably faster than the C-based event
1382	loops Event and Glib, although the difference is too small to really	1643	loops Event and Glib, although the difference is too small to really
1383	matter.	1644	matter.
1384		1645
1385	POE also performs much better in this case, but is is still far behind the	1646	POE also performs much better in this case, but is is still far behind the
1386	others.	1647	others.
…		…
1415	specified in the variable.	1676	specified in the variable.
1416		1677
1417	You can make AnyEvent completely ignore this variable by deleting it	1678	You can make AnyEvent completely ignore this variable by deleting it
1418	before the first watcher gets created, e.g. with a C<BEGIN> block:	1679	before the first watcher gets created, e.g. with a C<BEGIN> block:
1419		1680
1420	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1681	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1421		1682
1422	use AnyEvent;	1683	use AnyEvent;
1423		1684
1424	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1685	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1425	be used to probe what backend is used and gain other information (which is	1686	be used to probe what backend is used and gain other information (which is
1426	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	1687	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
1427		1688
1428		1689
		1690	=head1 BUGS
		1691
		1692	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		1693	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		1694	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		1695	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as
		1696	pronounced).
		1697
		1698
1429	=head1 SEE ALSO	1699	=head1 SEE ALSO
		1700
		1701	Utility functions: L<AnyEvent::Util>.
1430		1702
1431	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	1703	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1432	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	1704	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1433		1705
1434	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	1706	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1435	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	1707	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1436	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	1708	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1437	L<AnyEvent::Impl::POE>.	1709	L<AnyEvent::Impl::POE>.
1438		1710
		1711	Non-blocking file handles, sockets, TCP clients and
		1712	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1713
		1714	Asynchronous DNS: L<AnyEvent::DNS>.
		1715
1439	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	1716	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
1440		1717
1441	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1718	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1442		1719
1443		1720
1444	=head1 AUTHOR	1721	=head1 AUTHOR
1445		1722
1446	Marc Lehmann <schmorp@schmorp.de>	1723	Marc Lehmann <schmorp@schmorp.de>
1447	http://home.schmorp.de/	1724	http://home.schmorp.de/
1448		1725
1449	=cut	1726	=cut
1450		1727
1451	1	1728	1
1452		1729

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.109 by root, Sat May 10 00:45:18 2008 UTC vs. Revision 1.165 by root, Tue Jul 8 23:07:26 2008 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.109 by root, Sat May 10 00:45:18 2008 UTC vs.
Revision 1.165 by root, Tue Jul 8 23:07:26 2008 UTC