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1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
6	event loops.	6	and POE are various supported event loops/environments.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
…		…
40	=head1 INTRODUCTION/TUTORIAL	40	=head1 INTRODUCTION/TUTORIAL
41		41
42	This manpage is mainly a reference manual. If you are interested	42	This manpage is mainly a reference manual. If you are interested
43	in a tutorial or some gentle introduction, have a look at the	43	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	44	L<AnyEvent::Intro> manpage.
		45
		46	=head1 SUPPORT
		47
		48	There is a mailinglist for discussing all things AnyEvent, and an IRC
		49	channel, too.
		50
		51	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		52	Repository>, at L<http://anyevent.schmorp.de>, for more info.
45		53
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	54	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		55
48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	56	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49	nowadays. So what is different about AnyEvent?	57	nowadays. So what is different about AnyEvent?
…		…
173	my variables are only visible after the statement in which they are	181	my variables are only visible after the statement in which they are
174	declared.	182	declared.
175		183
176	=head2 I/O WATCHERS	184	=head2 I/O WATCHERS
177		185
		186	$w = AnyEvent->io (
		187	fh => <filehandle_or_fileno>,
		188	poll => <"r" or "w">,
		189	cb => <callback>,
		190	);
		191
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	192	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	193	with the following mandatory key-value pairs as arguments:
180		194
181	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch	195	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
182	for events (AnyEvent might or might not keep a reference to this file	196	for events (AnyEvent might or might not keep a reference to this file
183	handle). Note that only file handles pointing to things for which	197	handle). Note that only file handles pointing to things for which
184	non-blocking operation makes sense are allowed. This includes sockets,	198	non-blocking operation makes sense are allowed. This includes sockets,
185	most character devices, pipes, fifos and so on, but not for example files	199	most character devices, pipes, fifos and so on, but not for example files
186	or block devices.	200	or block devices.
…		…
211	undef $w;	225	undef $w;
212	});	226	});
213		227
214	=head2 TIME WATCHERS	228	=head2 TIME WATCHERS
215		229
		230	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		231
		232	$w = AnyEvent->timer (
		233	after => <fractional_seconds>,
		234	interval => <fractional_seconds>,
		235	cb => <callback>,
		236	);
		237
216	You can create a time watcher by calling the C<< AnyEvent->timer >>	238	You can create a time watcher by calling the C<< AnyEvent->timer >>
217	method with the following mandatory arguments:	239	method with the following mandatory arguments:
218		240
219	C<after> specifies after how many seconds (fractional values are	241	C<after> specifies after how many seconds (fractional values are
220	supported) the callback should be invoked. C<cb> is the callback to invoke	242	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
347		369
348	=back	370	=back
349		371
350	=head2 SIGNAL WATCHERS	372	=head2 SIGNAL WATCHERS
351		373
		374	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
		375
352	You can watch for signals using a signal watcher, C<signal> is the signal	376	You can watch for signals using a signal watcher, C<signal> is the signal
353	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	377	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354	callback to be invoked whenever a signal occurs.	378	callback to be invoked whenever a signal occurs.
355		379
356	Although the callback might get passed parameters, their value and	380	Although the callback might get passed parameters, their value and
…		…
361	invocation, and callback invocation will be synchronous. Synchronous means	385	invocation, and callback invocation will be synchronous. Synchronous means
362	that it might take a while until the signal gets handled by the process,	386	that it might take a while until the signal gets handled by the process,
363	but it is guaranteed not to interrupt any other callbacks.	387	but it is guaranteed not to interrupt any other callbacks.
364		388
365	The main advantage of using these watchers is that you can share a signal	389	The main advantage of using these watchers is that you can share a signal
366	between multiple watchers.	390	between multiple watchers, and AnyEvent will ensure that signals will not
		391	interrupt your program at bad times.
367		392
368	This watcher might use C<%SIG>, so programs overwriting those signals	393	This watcher might use C<%SIG> (depending on the event loop used),
369	directly will likely not work correctly.	394	so programs overwriting those signals directly will likely not work
		395	correctly.
370		396
371	Example: exit on SIGINT	397	Example: exit on SIGINT
372		398
373	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	399	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
374		400
		401	=head3 Signal Races, Delays and Workarounds
		402
		403	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		404	callbacks to signals in a generic way, which is a pity, as you cannot
		405	do race-free signal handling in perl, requiring C libraries for
		406	this. AnyEvent will try to do it's best, which means in some cases,
		407	signals will be delayed. The maximum time a signal might be delayed is
		408	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		409	variable can be changed only before the first signal watcher is created,
		410	and should be left alone otherwise. This variable determines how often
		411	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		412	will cause fewer spurious wake-ups, which is better for power and CPU
		413	saving.
		414
		415	All these problems can be avoided by installing the optional
		416	L<Async::Interrupt> module, which works with most event loops. It will not
		417	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		418	(and not with L<POE> currently, as POE does it's own workaround with
		419	one-second latency). For those, you just have to suffer the delays.
		420
375	=head2 CHILD PROCESS WATCHERS	421	=head2 CHILD PROCESS WATCHERS
376		422
		423	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		424
377	You can also watch on a child process exit and catch its exit status.	425	You can also watch on a child process exit and catch its exit status.
378		426
379	The child process is specified by the C<pid> argument (if set to C<0>, it	427	The child process is specified by the C<pid> argument (one some backends,
380	watches for any child process exit). The watcher will triggered only when	428	using C<0> watches for any child process exit, on others this will
381	the child process has finished and an exit status is available, not on	429	croak). The watcher will be triggered only when the child process has
382	any trace events (stopped/continued).	430	finished and an exit status is available, not on any trace events
		431	(stopped/continued).
383		432
384	The callback will be called with the pid and exit status (as returned by	433	The callback will be called with the pid and exit status (as returned by
385	waitpid), so unlike other watcher types, you I<can> rely on child watcher	434	waitpid), so unlike other watcher types, you I<can> rely on child watcher
386	callback arguments.	435	callback arguments.
387		436
…		…
392		441
393	There is a slight catch to child watchers, however: you usually start them	442	There is a slight catch to child watchers, however: you usually start them
394	I<after> the child process was created, and this means the process could	443	I<after> the child process was created, and this means the process could
395	have exited already (and no SIGCHLD will be sent anymore).	444	have exited already (and no SIGCHLD will be sent anymore).
396		445
397	Not all event models handle this correctly (POE doesn't), but even for	446	Not all event models handle this correctly (neither POE nor IO::Async do,
		447	see their AnyEvent::Impl manpages for details), but even for event models
398	event models that I<do> handle this correctly, they usually need to be	448	that I<do> handle this correctly, they usually need to be loaded before
399	loaded before the process exits (i.e. before you fork in the first place).	449	the process exits (i.e. before you fork in the first place). AnyEvent's
		450	pure perl event loop handles all cases correctly regardless of when you
		451	start the watcher.
400		452
401	This means you cannot create a child watcher as the very first thing in an	453	This means you cannot create a child watcher as the very first
402	AnyEvent program, you I<have> to create at least one watcher before you	454	thing in an AnyEvent program, you I<have> to create at least one
403	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	455	watcher before you C<fork> the child (alternatively, you can call
		456	C<AnyEvent::detect>).
		457
		458	As most event loops do not support waiting for child events, they will be
		459	emulated by AnyEvent in most cases, in which the latency and race problems
		460	mentioned in the description of signal watchers apply.
404		461
405	Example: fork a process and wait for it	462	Example: fork a process and wait for it
406		463
407	my $done = AnyEvent->condvar;	464	my $done = AnyEvent->condvar;
408		465
…		…
420	# do something else, then wait for process exit	477	# do something else, then wait for process exit
421	$done->recv;	478	$done->recv;
422		479
423	=head2 IDLE WATCHERS	480	=head2 IDLE WATCHERS
424		481
		482	$w = AnyEvent->idle (cb => <callback>);
		483
425	Sometimes there is a need to do something, but it is not so important	484	Sometimes there is a need to do something, but it is not so important
426	to do it instantly, but only when there is nothing better to do. This	485	to do it instantly, but only when there is nothing better to do. This
427	"nothing better to do" is usually defined to be "no other events need	486	"nothing better to do" is usually defined to be "no other events need
428	attention by the event loop".	487	attention by the event loop".
429		488
…		…
455	});	514	});
456	});	515	});
457		516
458	=head2 CONDITION VARIABLES	517	=head2 CONDITION VARIABLES
459		518
		519	$cv = AnyEvent->condvar;
		520
		521	$cv->send (<list>);
		522	my @res = $cv->recv;
		523
460	If you are familiar with some event loops you will know that all of them	524	If you are familiar with some event loops you will know that all of them
461	require you to run some blocking "loop", "run" or similar function that	525	require you to run some blocking "loop", "run" or similar function that
462	will actively watch for new events and call your callbacks.	526	will actively watch for new events and call your callbacks.
463		527
464	AnyEvent is different, it expects somebody else to run the event loop and	528	AnyEvent is slightly different: it expects somebody else to run the event
465	will only block when necessary (usually when told by the user).	529	loop and will only block when necessary (usually when told by the user).
466		530
467	The instrument to do that is called a "condition variable", so called	531	The instrument to do that is called a "condition variable", so called
468	because they represent a condition that must become true.	532	because they represent a condition that must become true.
469		533
		534	Now is probably a good time to look at the examples further below.
		535
470	Condition variables can be created by calling the C<< AnyEvent->condvar	536	Condition variables can be created by calling the C<< AnyEvent->condvar
471	>> method, usually without arguments. The only argument pair allowed is	537	>> method, usually without arguments. The only argument pair allowed is
472
473	C<cb>, which specifies a callback to be called when the condition variable	538	C<cb>, which specifies a callback to be called when the condition variable
474	becomes true, with the condition variable as the first argument (but not	539	becomes true, with the condition variable as the first argument (but not
475	the results).	540	the results).
476		541
477	After creation, the condition variable is "false" until it becomes "true"	542	After creation, the condition variable is "false" until it becomes "true"
…		…
482	Condition variables are similar to callbacks, except that you can	547	Condition variables are similar to callbacks, except that you can
483	optionally wait for them. They can also be called merge points - points	548	optionally wait for them. They can also be called merge points - points
484	in time where multiple outstanding events have been processed. And yet	549	in time where multiple outstanding events have been processed. And yet
485	another way to call them is transactions - each condition variable can be	550	another way to call them is transactions - each condition variable can be
486	used to represent a transaction, which finishes at some point and delivers	551	used to represent a transaction, which finishes at some point and delivers
487	a result.	552	a result. And yet some people know them as "futures" - a promise to
		553	compute/deliver something that you can wait for.
488		554
489	Condition variables are very useful to signal that something has finished,	555	Condition variables are very useful to signal that something has finished,
490	for example, if you write a module that does asynchronous http requests,	556	for example, if you write a module that does asynchronous http requests,
491	then a condition variable would be the ideal candidate to signal the	557	then a condition variable would be the ideal candidate to signal the
492	availability of results. The user can either act when the callback is	558	availability of results. The user can either act when the callback is
…		…
526	after => 1,	592	after => 1,
527	cb => sub { $result_ready->send },	593	cb => sub { $result_ready->send },
528	);	594	);
529		595
530	# this "blocks" (while handling events) till the callback	596	# this "blocks" (while handling events) till the callback
531	# calls send	597	# calls -<send
532	$result_ready->recv;	598	$result_ready->recv;
533		599
534	Example: wait for a timer, but take advantage of the fact that	600	Example: wait for a timer, but take advantage of the fact that condition
535	condition variables are also code references.	601	variables are also callable directly.
536		602
537	my $done = AnyEvent->condvar;	603	my $done = AnyEvent->condvar;
538	my $delay = AnyEvent->timer (after => 5, cb => $done);	604	my $delay = AnyEvent->timer (after => 5, cb => $done);
539	$done->recv;	605	$done->recv;
540		606
…		…
546		612
547	...	613	...
548		614
549	my @info = $couchdb->info->recv;	615	my @info = $couchdb->info->recv;
550		616
551	And this is how you would just ste a callback to be called whenever the	617	And this is how you would just set a callback to be called whenever the
552	results are available:	618	results are available:
553		619
554	$couchdb->info->cb (sub {	620	$couchdb->info->cb (sub {
555	my @info = $_[0]->recv;	621	my @info = $_[0]->recv;
556	});	622	});
…		…
574	immediately from within send.	640	immediately from within send.
575		641
576	Any arguments passed to the C<send> call will be returned by all	642	Any arguments passed to the C<send> call will be returned by all
577	future C<< ->recv >> calls.	643	future C<< ->recv >> calls.
578		644
579	Condition variables are overloaded so one can call them directly	645	Condition variables are overloaded so one can call them directly (as if
580	(as a code reference). Calling them directly is the same as calling	646	they were a code reference). Calling them directly is the same as calling
581	C<send>. Note, however, that many C-based event loops do not handle	647	C<send>.
582	overloading, so as tempting as it may be, passing a condition variable
583	instead of a callback does not work. Both the pure perl and EV loops
584	support overloading, however, as well as all functions that use perl to
585	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
586	example).
587		648
588	=item $cv->croak ($error)	649	=item $cv->croak ($error)
589		650
590	Similar to send, but causes all call's to C<< ->recv >> to invoke	651	Similar to send, but causes all call's to C<< ->recv >> to invoke
591	C<Carp::croak> with the given error message/object/scalar.	652	C<Carp::croak> with the given error message/object/scalar.
592		653
593	This can be used to signal any errors to the condition variable	654	This can be used to signal any errors to the condition variable
594	user/consumer.	655	user/consumer. Doing it this way instead of calling C<croak> directly
		656	delays the error detetcion, but has the overwhelmign advantage that it
		657	diagnoses the error at the place where the result is expected, and not
		658	deep in some event clalback without connection to the actual code causing
		659	the problem.
595		660
596	=item $cv->begin ([group callback])	661	=item $cv->begin ([group callback])
597		662
598	=item $cv->end	663	=item $cv->end
599
600	These two methods are EXPERIMENTAL and MIGHT CHANGE.
601		664
602	These two methods can be used to combine many transactions/events into	665	These two methods can be used to combine many transactions/events into
603	one. For example, a function that pings many hosts in parallel might want	666	one. For example, a function that pings many hosts in parallel might want
604	to use a condition variable for the whole process.	667	to use a condition variable for the whole process.
605		668
…		…
607	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	670	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
608	>>, the (last) callback passed to C<begin> will be executed. That callback	671	>>, the (last) callback passed to C<begin> will be executed. That callback
609	is I<supposed> to call C<< ->send >>, but that is not required. If no	672	is I<supposed> to call C<< ->send >>, but that is not required. If no
610	callback was set, C<send> will be called without any arguments.	673	callback was set, C<send> will be called without any arguments.
611		674
612	Let's clarify this with the ping example:	675	You can think of C<< $cv->send >> giving you an OR condition (one call
		676	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		677	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		678
		679	Let's start with a simple example: you have two I/O watchers (for example,
		680	STDOUT and STDERR for a program), and you want to wait for both streams to
		681	close before activating a condvar:
		682
		683	my $cv = AnyEvent->condvar;
		684
		685	$cv->begin; # first watcher
		686	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		687	defined sysread $fh1, my $buf, 4096
		688	or $cv->end;
		689	});
		690
		691	$cv->begin; # second watcher
		692	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		693	defined sysread $fh2, my $buf, 4096
		694	or $cv->end;
		695	});
		696
		697	$cv->recv;
		698
		699	This works because for every event source (EOF on file handle), there is
		700	one call to C<begin>, so the condvar waits for all calls to C<end> before
		701	sending.
		702
		703	The ping example mentioned above is slightly more complicated, as the
		704	there are results to be passwd back, and the number of tasks that are
		705	begung can potentially be zero:
613		706
614	my $cv = AnyEvent->condvar;	707	my $cv = AnyEvent->condvar;
615		708
616	my %result;	709	my %result;
617	$cv->begin (sub { $cv->send (\%result) });	710	$cv->begin (sub { $cv->send (\%result) });
…		…
637	loop, which serves two important purposes: first, it sets the callback	730	loop, which serves two important purposes: first, it sets the callback
638	to be called once the counter reaches C<0>, and second, it ensures that	731	to be called once the counter reaches C<0>, and second, it ensures that
639	C<send> is called even when C<no> hosts are being pinged (the loop	732	C<send> is called even when C<no> hosts are being pinged (the loop
640	doesn't execute once).	733	doesn't execute once).
641		734
642	This is the general pattern when you "fan out" into multiple subrequests:	735	This is the general pattern when you "fan out" into multiple (but
643	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	736	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
644	is called at least once, and then, for each subrequest you start, call	737	the callback and ensure C<end> is called at least once, and then, for each
645	C<begin> and for each subrequest you finish, call C<end>.	738	subrequest you start, call C<begin> and for each subrequest you finish,
		739	call C<end>.
646		740
647	=back	741	=back
648		742
649	=head3 METHODS FOR CONSUMERS	743	=head3 METHODS FOR CONSUMERS
650		744
…		…
666	function will call C<croak>.	760	function will call C<croak>.
667		761
668	In list context, all parameters passed to C<send> will be returned,	762	In list context, all parameters passed to C<send> will be returned,
669	in scalar context only the first one will be returned.	763	in scalar context only the first one will be returned.
670		764
		765	Note that doing a blocking wait in a callback is not supported by any
		766	event loop, that is, recursive invocation of a blocking C<< ->recv
		767	>> is not allowed, and the C<recv> call will C<croak> if such a
		768	condition is detected. This condition can be slightly loosened by using
		769	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		770	any thread that doesn't run the event loop itself.
		771
671	Not all event models support a blocking wait - some die in that case	772	Not all event models support a blocking wait - some die in that case
672	(programs might want to do that to stay interactive), so I<if you are	773	(programs might want to do that to stay interactive), so I<if you are
673	using this from a module, never require a blocking wait>, but let the	774	using this from a module, never require a blocking wait>. Instead, let the
674	caller decide whether the call will block or not (for example, by coupling	775	caller decide whether the call will block or not (for example, by coupling
675	condition variables with some kind of request results and supporting	776	condition variables with some kind of request results and supporting
676	callbacks so the caller knows that getting the result will not block,	777	callbacks so the caller knows that getting the result will not block,
677	while still supporting blocking waits if the caller so desires).	778	while still supporting blocking waits if the caller so desires).
678		779
679	Another reason I<never> to C<< ->recv >> in a module is that you cannot
680	sensibly have two C<< ->recv >>'s in parallel, as that would require
681	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
682	can supply.
683
684	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
685	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
686	versions and also integrates coroutines into AnyEvent, making blocking
687	C<< ->recv >> calls perfectly safe as long as they are done from another
688	coroutine (one that doesn't run the event loop).
689
690	You can ensure that C<< -recv >> never blocks by setting a callback and	780	You can ensure that C<< -recv >> never blocks by setting a callback and
691	only calling C<< ->recv >> from within that callback (or at a later	781	only calling C<< ->recv >> from within that callback (or at a later
692	time). This will work even when the event loop does not support blocking	782	time). This will work even when the event loop does not support blocking
693	waits otherwise.	783	waits otherwise.
694		784
…		…
700	=item $cb = $cv->cb ($cb->($cv))	790	=item $cb = $cv->cb ($cb->($cv))
701		791
702	This is a mutator function that returns the callback set and optionally	792	This is a mutator function that returns the callback set and optionally
703	replaces it before doing so.	793	replaces it before doing so.
704		794
705	The callback will be called when the condition becomes "true", i.e. when	795	The callback will be called when the condition becomes (or already was)
706	C<send> or C<croak> are called, with the only argument being the condition	796	"true", i.e. when C<send> or C<croak> are called (or were called), with
707	variable itself. Calling C<recv> inside the callback or at any later time	797	the only argument being the condition variable itself. Calling C<recv>
708	is guaranteed not to block.	798	inside the callback or at any later time is guaranteed not to block.
709		799
710	=back	800	=back
711		801
		802	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		803
		804	The available backend classes are (every class has its own manpage):
		805
		806	=over 4
		807
		808	=item Backends that are autoprobed when no other event loop can be found.
		809
		810	EV is the preferred backend when no other event loop seems to be in
		811	use. If EV is not installed, then AnyEvent will try Event, and, failing
		812	that, will fall back to its own pure-perl implementation, which is
		813	available everywhere as it comes with AnyEvent itself.
		814
		815	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		816	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		817	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		818
		819	=item Backends that are transparently being picked up when they are used.
		820
		821	These will be used when they are currently loaded when the first watcher
		822	is created, in which case it is assumed that the application is using
		823	them. This means that AnyEvent will automatically pick the right backend
		824	when the main program loads an event module before anything starts to
		825	create watchers. Nothing special needs to be done by the main program.
		826
		827	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		828	AnyEvent::Impl::Tk based on Tk, very broken.
		829	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		830	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		831	AnyEvent::Impl::Irssi used when running within irssi.
		832
		833	=item Backends with special needs.
		834
		835	Qt requires the Qt::Application to be instantiated first, but will
		836	otherwise be picked up automatically. As long as the main program
		837	instantiates the application before any AnyEvent watchers are created,
		838	everything should just work.
		839
		840	AnyEvent::Impl::Qt based on Qt.
		841
		842	Support for IO::Async can only be partial, as it is too broken and
		843	architecturally limited to even support the AnyEvent API. It also
		844	is the only event loop that needs the loop to be set explicitly, so
		845	it can only be used by a main program knowing about AnyEvent. See
		846	L<AnyEvent::Impl::Async> for the gory details.
		847
		848	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		849
		850	=item Event loops that are indirectly supported via other backends.
		851
		852	Some event loops can be supported via other modules:
		853
		854	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		855
		856	B<WxWidgets> has no support for watching file handles. However, you can
		857	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		858	polls 20 times per second, which was considered to be too horrible to even
		859	consider for AnyEvent.
		860
		861	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		862	backend, so it can be supported through POE.
		863
		864	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		865	load L<POE> when detecting them, in the hope that POE will pick them up,
		866	in which case everything will be automatic.
		867
		868	=back
		869
712	=head1 GLOBAL VARIABLES AND FUNCTIONS	870	=head1 GLOBAL VARIABLES AND FUNCTIONS
713		871
		872	These are not normally required to use AnyEvent, but can be useful to
		873	write AnyEvent extension modules.
		874
714	=over 4	875	=over 4
715		876
716	=item $AnyEvent::MODEL	877	=item $AnyEvent::MODEL
717		878
718	Contains C<undef> until the first watcher is being created. Then it	879	Contains C<undef> until the first watcher is being created, before the
		880	backend has been autodetected.
		881
719	contains the event model that is being used, which is the name of the	882	Afterwards it contains the event model that is being used, which is the
720	Perl class implementing the model. This class is usually one of the	883	name of the Perl class implementing the model. This class is usually one
721	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	884	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
722	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	885	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
723		886	will be C<urxvt::anyevent>).
724	The known classes so far are:
725
726	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
727	AnyEvent::Impl::Event based on Event, second best choice.
728	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
729	AnyEvent::Impl::Glib based on Glib, third-best choice.
730	AnyEvent::Impl::Tk based on Tk, very bad choice.
731	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
732	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
733	AnyEvent::Impl::POE based on POE, not generic enough for full support.
734
735	There is no support for WxWidgets, as WxWidgets has no support for
736	watching file handles. However, you can use WxWidgets through the
737	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
738	second, which was considered to be too horrible to even consider for
739	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
740	it's adaptor.
741
742	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
743	autodetecting them.
744		887
745	=item AnyEvent::detect	888	=item AnyEvent::detect
746		889
747	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	890	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
748	if necessary. You should only call this function right before you would	891	if necessary. You should only call this function right before you would
749	have created an AnyEvent watcher anyway, that is, as late as possible at	892	have created an AnyEvent watcher anyway, that is, as late as possible at
750	runtime.	893	runtime, and not e.g. while initialising of your module.
		894
		895	If you need to do some initialisation before AnyEvent watchers are
		896	created, use C<post_detect>.
751		897
752	=item $guard = AnyEvent::post_detect { BLOCK }	898	=item $guard = AnyEvent::post_detect { BLOCK }
753		899
754	Arranges for the code block to be executed as soon as the event model is	900	Arranges for the code block to be executed as soon as the event model is
755	autodetected (or immediately if this has already happened).	901	autodetected (or immediately if this has already happened).
756		902
		903	The block will be executed I<after> the actual backend has been detected
		904	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		905	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		906	other initialisations - see the sources of L<AnyEvent::Strict> or
		907	L<AnyEvent::AIO> to see how this is used.
		908
		909	The most common usage is to create some global watchers, without forcing
		910	event module detection too early, for example, L<AnyEvent::AIO> creates
		911	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		912	avoid autodetecting the event module at load time.
		913
757	If called in scalar or list context, then it creates and returns an object	914	If called in scalar or list context, then it creates and returns an object
758	that automatically removes the callback again when it is destroyed. See	915	that automatically removes the callback again when it is destroyed (or
		916	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
759	L<Coro::BDB> for a case where this is useful.	917	a case where this is useful.
		918
		919	Example: Create a watcher for the IO::AIO module and store it in
		920	C<$WATCHER>. Only do so after the event loop is initialised, though.
		921
		922	our WATCHER;
		923
		924	my $guard = AnyEvent::post_detect {
		925	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		926	};
		927
		928	# the ||= is important in case post_detect immediately runs the block,
		929	# as to not clobber the newly-created watcher. assigning both watcher and
		930	# post_detect guard to the same variable has the advantage of users being
		931	# able to just C<undef $WATCHER> if the watcher causes them grief.
		932
		933	$WATCHER ||= $guard;
760		934
761	=item @AnyEvent::post_detect	935	=item @AnyEvent::post_detect
762		936
763	If there are any code references in this array (you can C<push> to it	937	If there are any code references in this array (you can C<push> to it
764	before or after loading AnyEvent), then they will called directly after	938	before or after loading AnyEvent), then they will called directly after
765	the event loop has been chosen.	939	the event loop has been chosen.
766		940
767	You should check C<$AnyEvent::MODEL> before adding to this array, though:	941	You should check C<$AnyEvent::MODEL> before adding to this array, though:
768	if it contains a true value then the event loop has already been detected,	942	if it is defined then the event loop has already been detected, and the
769	and the array will be ignored.	943	array will be ignored.
770		944
771	Best use C<AnyEvent::post_detect { BLOCK }> instead.	945	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		946	it,as it takes care of these details.
		947
		948	This variable is mainly useful for modules that can do something useful
		949	when AnyEvent is used and thus want to know when it is initialised, but do
		950	not need to even load it by default. This array provides the means to hook
		951	into AnyEvent passively, without loading it.
772		952
773	=back	953	=back
774		954
775	=head1 WHAT TO DO IN A MODULE	955	=head1 WHAT TO DO IN A MODULE
776		956
…		…
831		1011
832		1012
833	=head1 OTHER MODULES	1013	=head1 OTHER MODULES
834		1014
835	The following is a non-exhaustive list of additional modules that use	1015	The following is a non-exhaustive list of additional modules that use
836	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1016	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
837	in the same program. Some of the modules come with AnyEvent, some are	1017	modules and other event loops in the same program. Some of the modules
838	available via CPAN.	1018	come with AnyEvent, most are available via CPAN.
839		1019
840	=over 4	1020	=over 4
841		1021
842	=item L<AnyEvent::Util>	1022	=item L<AnyEvent::Util>
843		1023
…		…
852		1032
853	=item L<AnyEvent::Handle>	1033	=item L<AnyEvent::Handle>
854		1034
855	Provide read and write buffers, manages watchers for reads and writes,	1035	Provide read and write buffers, manages watchers for reads and writes,
856	supports raw and formatted I/O, I/O queued and fully transparent and	1036	supports raw and formatted I/O, I/O queued and fully transparent and
857	non-blocking SSL/TLS.	1037	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
858		1038
859	=item L<AnyEvent::DNS>	1039	=item L<AnyEvent::DNS>
860		1040
861	Provides rich asynchronous DNS resolver capabilities.	1041	Provides rich asynchronous DNS resolver capabilities.
862		1042
…		…
890		1070
891	=item L<AnyEvent::GPSD>	1071	=item L<AnyEvent::GPSD>
892		1072
893	A non-blocking interface to gpsd, a daemon delivering GPS information.	1073	A non-blocking interface to gpsd, a daemon delivering GPS information.
894		1074
		1075	=item L<AnyEvent::IRC>
		1076
		1077	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1078
		1079	=item L<AnyEvent::XMPP>
		1080
		1081	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1082	Net::XMPP2>.
		1083
895	=item L<AnyEvent::IGS>	1084	=item L<AnyEvent::IGS>
896		1085
897	A non-blocking interface to the Internet Go Server protocol (used by	1086	A non-blocking interface to the Internet Go Server protocol (used by
898	L<App::IGS>).	1087	L<App::IGS>).
899		1088
900	=item L<AnyEvent::IRC>
901
902	AnyEvent based IRC client module family (replacing the older Net::IRC3).
903
904	=item L<Net::XMPP2>
905
906	AnyEvent based XMPP (Jabber protocol) module family.
907
908	=item L<Net::FCP>	1089	=item L<Net::FCP>
909		1090
910	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1091	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
911	of AnyEvent.	1092	of AnyEvent.
912		1093
…		…
916		1097
917	=item L<Coro>	1098	=item L<Coro>
918		1099
919	Has special support for AnyEvent via L<Coro::AnyEvent>.	1100	Has special support for AnyEvent via L<Coro::AnyEvent>.
920		1101
921	=item L<IO::Lambda>
922
923	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
924
925	=back	1102	=back
926		1103
927	=cut	1104	=cut
928		1105
929	package AnyEvent;	1106	package AnyEvent;
930		1107
		1108	# basically a tuned-down version of common::sense
		1109	sub common_sense {
931	no warnings;	1110	# no warnings
		1111	${^WARNING_BITS} ^= ${^WARNING_BITS};
932	use strict qw(vars subs);	1112	# use strict vars subs
		1113	$^H |= 0x00000600;
		1114	}
933		1115
		1116	BEGIN { AnyEvent::common_sense }
		1117
934	use Carp;	1118	use Carp ();
935		1119
936	our $VERSION = 4.411;	1120	our $VERSION = 4.9;
937	our $MODEL;	1121	our $MODEL;
938		1122
939	our $AUTOLOAD;	1123	our $AUTOLOAD;
940	our @ISA;	1124	our @ISA;
941		1125
942	our @REGISTRY;	1126	our @REGISTRY;
943		1127
944	our $WIN32;	1128	our $WIN32;
945		1129
		1130	our $VERBOSE;
		1131
946	BEGIN {	1132	BEGIN {
947	my $win32 = ! ! ($^O =~ /mswin32/i);	1133	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
948	eval "sub WIN32(){ $win32 }";	1134	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
949	}
950		1135
		1136	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1137	if ${^TAINT};
		1138
951	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1139	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1140
		1141	}
		1142
		1143	our $MAX_SIGNAL_LATENCY = 10;
952		1144
953	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1145	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
954		1146
955	{	1147	{
956	my $idx;	1148	my $idx;
…		…
958	for reverse split /\s*,\s*/,	1150	for reverse split /\s*,\s*/,
959	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1151	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
960	}	1152	}
961		1153
962	my @models = (	1154	my @models = (
963	[EV:: => AnyEvent::Impl::EV::],	1155	[EV:: => AnyEvent::Impl::EV:: , 1],
964	[Event:: => AnyEvent::Impl::Event::],	1156	[Event:: => AnyEvent::Impl::Event::, 1],
965	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1157	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
966	# everything below here will not be autoprobed	1158	# everything below here will not (normally) be autoprobed
967	# as the pureperl backend should work everywhere	1159	# as the pureperl backend should work everywhere
968	# and is usually faster	1160	# and is usually faster
		1161	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1162	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1163	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
969	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1164	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
970	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
971	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
972	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1165	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
973	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1166	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
974	[Wx:: => AnyEvent::Impl::POE::],	1167	[Wx:: => AnyEvent::Impl::POE::],
975	[Prima:: => AnyEvent::Impl::POE::],	1168	[Prima:: => AnyEvent::Impl::POE::],
		1169	# IO::Async is just too broken - we would need workarounds for its
		1170	# byzantine signal and broken child handling, among others.
		1171	# IO::Async is rather hard to detect, as it doesn't have any
		1172	# obvious default class.
		1173	# [0, IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1174	# [0, IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1175	# [0, IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
976	);	1176	);
977		1177
978	our %method = map +($_ => 1),	1178	our %method = map +($_ => 1),
979	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1179	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
980		1180
…		…
984	my ($cb) = @_;	1184	my ($cb) = @_;
985		1185
986	if ($MODEL) {	1186	if ($MODEL) {
987	$cb->();	1187	$cb->();
988		1188
989	1	1189	undef
990	} else {	1190	} else {
991	push @post_detect, $cb;	1191	push @post_detect, $cb;
992		1192
993	defined wantarray	1193	defined wantarray
994	? bless \$cb, "AnyEvent::Util::postdetect"	1194	? bless \$cb, "AnyEvent::Util::postdetect"
…		…
1000	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1200	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1001	}	1201	}
1002		1202
1003	sub detect() {	1203	sub detect() {
1004	unless ($MODEL) {	1204	unless ($MODEL) {
1005	no strict 'refs';
1006	local $SIG{__DIE__};	1205	local $SIG{__DIE__};
1007		1206
1008	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1207	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1009	my $model = "AnyEvent::Impl::$1";	1208	my $model = "AnyEvent::Impl::$1";
1010	if (eval "require $model") {	1209	if (eval "require $model") {
1011	$MODEL = $model;	1210	$MODEL = $model;
1012	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1211	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1013	} else {	1212	} else {
1014	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1213	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1015	}	1214	}
1016	}	1215	}
1017		1216
1018	# check for already loaded models	1217	# check for already loaded models
1019	unless ($MODEL) {	1218	unless ($MODEL) {
1020	for (@REGISTRY, @models) {	1219	for (@REGISTRY, @models) {
1021	my ($package, $model) = @$_;	1220	my ($package, $model) = @$_;
1022	if (${"$package\::VERSION"} > 0) {	1221	if (${"$package\::VERSION"} > 0) {
1023	if (eval "require $model") {	1222	if (eval "require $model") {
1024	$MODEL = $model;	1223	$MODEL = $model;
1025	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1224	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1026	last;	1225	last;
1027	}	1226	}
1028	}	1227	}
1029	}	1228	}
1030		1229
1031	unless ($MODEL) {	1230	unless ($MODEL) {
1032	# try to load a model	1231	# try to autoload a model
1033
1034	for (@REGISTRY, @models) {	1232	for (@REGISTRY, @models) {
1035	my ($package, $model) = @$_;	1233	my ($package, $model, $autoload) = @$_;
		1234	if (
		1235	$autoload
1036	if (eval "require $package"	1236	and eval "require $package"
1037	and ${"$package\::VERSION"} > 0	1237	and ${"$package\::VERSION"} > 0
1038	and eval "require $model") {	1238	and eval "require $model"
		1239	) {
1039	$MODEL = $model;	1240	$MODEL = $model;
1040	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1241	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1041	last;	1242	last;
1042	}	1243	}
1043	}	1244	}
1044		1245
1045	$MODEL	1246	$MODEL
…		…
1061		1262
1062	sub AUTOLOAD {	1263	sub AUTOLOAD {
1063	(my $func = $AUTOLOAD) =~ s/.*://;	1264	(my $func = $AUTOLOAD) =~ s/.*://;
1064		1265
1065	$method{$func}	1266	$method{$func}
1066	or croak "$func: not a valid method for AnyEvent objects";	1267	or Carp::croak "$func: not a valid method for AnyEvent objects";
1067		1268
1068	detect unless $MODEL;	1269	detect unless $MODEL;
1069		1270
1070	my $class = shift;	1271	my $class = shift;
1071	$class->$func (@_);	1272	$class->$func (@_);
1072	}	1273	}
1073		1274
1074	# utility function to dup a filehandle. this is used by many backends	1275	# utility function to dup a filehandle. this is used by many backends
1075	# to support binding more than one watcher per filehandle (they usually	1276	# to support binding more than one watcher per filehandle (they usually
1076	# allow only one watcher per fd, so we dup it to get a different one).	1277	# allow only one watcher per fd, so we dup it to get a different one).
1077	sub _dupfh($$$$) {	1278	sub _dupfh($$;$$) {
1078	my ($poll, $fh, $r, $w) = @_;	1279	my ($poll, $fh, $r, $w) = @_;
1079		1280
1080	# cygwin requires the fh mode to be matching, unix doesn't	1281	# cygwin requires the fh mode to be matching, unix doesn't
1081	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1282	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1082	: $poll eq "w" ? ($w, ">")
1083	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1084		1283
1085	open my $fh2, "$mode&" . fileno $fh	1284	open my $fh2, $mode, $fh
1086	or die "cannot dup() filehandle: $!,";	1285	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1087		1286
1088	# we assume CLOEXEC is already set by perl in all important cases	1287	# we assume CLOEXEC is already set by perl in all important cases
1089		1288
1090	($fh2, $rw)	1289	($fh2, $rw)
1091	}	1290	}
1092		1291
1093	package AnyEvent::Base;	1292	package AnyEvent::Base;
1094		1293
1095	# default implementations for many methods	1294	# default implementations for many methods
1096		1295
1097	BEGIN {	1296	sub _time {
		1297	# probe for availability of Time::HiRes
1098	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1298	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1299	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1099	*_time = \&Time::HiRes::time;	1300	*_time = \&Time::HiRes::time;
1100	# if (eval "use POSIX (); (POSIX::times())...	1301	# if (eval "use POSIX (); (POSIX::times())...
1101	} else {	1302	} else {
		1303	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1102	*_time = sub { time }; # epic fail	1304	*_time = sub { time }; # epic fail
1103	}	1305	}
		1306
		1307	&_time
1104	}	1308	}
1105		1309
1106	sub time { _time }	1310	sub time { _time }
1107	sub now { _time }	1311	sub now { _time }
1108	sub now_update { }	1312	sub now_update { }
…		…
1113	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1317	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1114	}	1318	}
1115		1319
1116	# default implementation for ->signal	1320	# default implementation for ->signal
1117		1321
		1322	our $HAVE_ASYNC_INTERRUPT;
		1323
		1324	sub _have_async_interrupt() {
		1325	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1326	&& eval "use Async::Interrupt 1.0 (); 1")
		1327	unless defined $HAVE_ASYNC_INTERRUPT;
		1328
		1329	$HAVE_ASYNC_INTERRUPT
		1330	}
		1331
1118	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1332	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1333	our (%SIG_ASY, %SIG_ASY_W);
		1334	our ($SIG_COUNT, $SIG_TW);
1119		1335
1120	sub _signal_exec {	1336	sub _signal_exec {
		1337	$HAVE_ASYNC_INTERRUPT
		1338	? $SIGPIPE_R->drain
1121	sysread $SIGPIPE_R, my $dummy, 4;	1339	: sysread $SIGPIPE_R, my $dummy, 9;
1122		1340
1123	while (%SIG_EV) {	1341	while (%SIG_EV) {
1124	for (keys %SIG_EV) {	1342	for (keys %SIG_EV) {
1125	delete $SIG_EV{$_};	1343	delete $SIG_EV{$_};
1126	$_->() for values %{ $SIG_CB{$_} || {} };	1344	$_->() for values %{ $SIG_CB{$_} || {} };
1127	}	1345	}
1128	}	1346	}
1129	}	1347	}
1130		1348
		1349	# install a dummy wakeup watcher to reduce signal catching latency
		1350	sub _sig_add() {
		1351	unless ($SIG_COUNT++) {
		1352	# try to align timer on a full-second boundary, if possible
		1353	my $NOW = AnyEvent->now;
		1354
		1355	$SIG_TW = AnyEvent->timer (
		1356	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1357	interval => $MAX_SIGNAL_LATENCY,
		1358	cb => sub { }, # just for the PERL_ASYNC_CHECK
		1359	);
		1360	}
		1361	}
		1362
		1363	sub _sig_del {
		1364	undef $SIG_TW
		1365	unless --$SIG_COUNT;
		1366	}
		1367
		1368	our $_sig_name_init; $_sig_name_init = sub {
		1369	eval q{ # poor man's autoloading
		1370	undef $_sig_name_init;
		1371
		1372	if (_have_async_interrupt) {
		1373	*sig2num = \&Async::Interrupt::sig2num;
		1374	*sig2name = \&Async::Interrupt::sig2name;
		1375	} else {
		1376	require Config;
		1377
		1378	my %signame2num;
		1379	@signame2num{ split ' ', $Config::Config{sig_name} }
		1380	= split ' ', $Config::Config{sig_num};
		1381
		1382	my @signum2name;
		1383	@signum2name[values %signame2num] = keys %signame2num;
		1384
		1385	*sig2num = sub($) {
		1386	$_[0] > 0 ? shift : $signame2num{+shift}
		1387	};
		1388	*sig2name = sub ($) {
		1389	$_[0] > 0 ? $signum2name[+shift] : shift
		1390	};
		1391	}
		1392	};
		1393	die if $@;
		1394	};
		1395
		1396	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1397	sub sig2name($) { &$_sig_name_init; &sig2name }
		1398
1131	sub signal {	1399	sub signal {
1132	my (undef, %arg) = @_;	1400	eval q{ # poor man's autoloading {}
		1401	# probe for availability of Async::Interrupt
		1402	if (_have_async_interrupt) {
		1403	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1133		1404
1134	unless ($SIGPIPE_R) {	1405	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1135	require Fcntl;	1406	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1136		1407
1137	if (AnyEvent::WIN32) {
1138	require AnyEvent::Util;
1139
1140	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1141	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1142	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1143	} else {	1408	} else {
		1409	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1410
		1411	require Fcntl;
		1412
		1413	if (AnyEvent::WIN32) {
		1414	require AnyEvent::Util;
		1415
		1416	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1417	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1418	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1419	} else {
1144	pipe $SIGPIPE_R, $SIGPIPE_W;	1420	pipe $SIGPIPE_R, $SIGPIPE_W;
1145	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1421	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1146	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1422	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1147		1423
1148	# not strictly required, as $^F is normally 2, but let's make sure...	1424	# not strictly required, as $^F is normally 2, but let's make sure...
1149	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1425	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1150	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1426	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1427	}
		1428
		1429	$SIGPIPE_R
		1430	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1431
		1432	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1151	}	1433	}
1152		1434
1153	$SIGPIPE_R	1435	*signal = sub {
1154	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1436	my (undef, %arg) = @_;
1155		1437
1156	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1157	}
1158
1159	my $signal = uc $arg{signal}	1438	my $signal = uc $arg{signal}
1160	or Carp::croak "required option 'signal' is missing";	1439	or Carp::croak "required option 'signal' is missing";
1161		1440
		1441	if ($HAVE_ASYNC_INTERRUPT) {
		1442	# async::interrupt
		1443
		1444	$signal = sig2num $signal;
1162	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1445	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1446
		1447	$SIG_ASY{$signal} ||= new Async::Interrupt
		1448	cb => sub { undef $SIG_EV{$signal} },
		1449	signal => $signal,
		1450	pipe => [$SIGPIPE_R->filenos],
		1451	pipe_autodrain => 0,
		1452	;
		1453
		1454	} else {
		1455	# pure perl
		1456
		1457	# AE::Util has been loaded in signal
		1458	$signal = sig2name $signal;
		1459	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1460
1163	$SIG{$signal} ||= sub {	1461	$SIG{$signal} ||= sub {
1164	local $!;	1462	local $!;
1165	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1463	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1166	undef $SIG_EV{$signal};	1464	undef $SIG_EV{$signal};
		1465	};
		1466
		1467	# can't do signal processing without introducing races in pure perl,
		1468	# so limit the signal latency.
		1469	_sig_add;
		1470	}
		1471
		1472	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1473	};
		1474
		1475	*AnyEvent::Base::signal::DESTROY = sub {
		1476	my ($signal, $cb) = @{$_[0]};
		1477
		1478	_sig_del;
		1479
		1480	delete $SIG_CB{$signal}{$cb};
		1481
		1482	$HAVE_ASYNC_INTERRUPT
		1483	? delete $SIG_ASY{$signal}
		1484	: # delete doesn't work with older perls - they then
		1485	# print weird messages, or just unconditionally exit
		1486	# instead of getting the default action.
		1487	undef $SIG{$signal}
		1488	unless keys %{ $SIG_CB{$signal} };
		1489	};
1167	};	1490	};
1168		1491	die if $@;
1169	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1492	&signal
1170	}
1171
1172	sub AnyEvent::Base::signal::DESTROY {
1173	my ($signal, $cb) = @{$_[0]};
1174
1175	delete $SIG_CB{$signal}{$cb};
1176
1177	# delete doesn't work with older perls - they then
1178	# print weird messages, or just unconditionally exit
1179	# instead of getting the default action.
1180	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1181	}	1493	}
1182		1494
1183	# default implementation for ->child	1495	# default implementation for ->child
1184		1496
1185	our %PID_CB;	1497	our %PID_CB;
1186	our $CHLD_W;	1498	our $CHLD_W;
1187	our $CHLD_DELAY_W;	1499	our $CHLD_DELAY_W;
1188	our $WNOHANG;	1500	our $WNOHANG;
1189		1501
		1502	sub _emit_childstatus($$) {
		1503	my (undef, $rpid, $rstatus) = @_;
		1504
		1505	$_->($rpid, $rstatus)
		1506	for values %{ $PID_CB{$rpid} || {} },
		1507	values %{ $PID_CB{0} || {} };
		1508	}
		1509
1190	sub _sigchld {	1510	sub _sigchld {
		1511	my $pid;
		1512
		1513	AnyEvent->_emit_childstatus ($pid, $?)
1191	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1514	while ($pid = waitpid -1, $WNOHANG) > 0;
1192	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),
1193	(values %{ $PID_CB{0} || {} });
1194	}
1195	}	1515	}
1196		1516
1197	sub child {	1517	sub child {
1198	my (undef, %arg) = @_;	1518	my (undef, %arg) = @_;
1199		1519
1200	defined (my $pid = $arg{pid} + 0)	1520	defined (my $pid = $arg{pid} + 0)
1201	or Carp::croak "required option 'pid' is missing";	1521	or Carp::croak "required option 'pid' is missing";
1202		1522
1203	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1523	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1204		1524
		1525	# WNOHANG is almost cetrainly 1 everywhere
		1526	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1527	? 1
1205	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1528	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1206		1529
1207	unless ($CHLD_W) {	1530	unless ($CHLD_W) {
1208	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1531	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1209	# child could be a zombie already, so make at least one round	1532	# child could be a zombie already, so make at least one round
1210	&_sigchld;	1533	&_sigchld;
…		…
1262		1585
1263	our @ISA = AnyEvent::CondVar::Base::;	1586	our @ISA = AnyEvent::CondVar::Base::;
1264		1587
1265	package AnyEvent::CondVar::Base;	1588	package AnyEvent::CondVar::Base;
1266		1589
1267	use overload	1590	#use overload
1268	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1591	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1269	fallback => 1;	1592	# fallback => 1;
		1593
		1594	# save 300+ kilobytes by dirtily hardcoding overloading
		1595	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1596	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1597	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1598	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1599
		1600	our $WAITING;
1270		1601
1271	sub _send {	1602	sub _send {
1272	# nop	1603	# nop
1273	}	1604	}
1274		1605
…		…
1287	sub ready {	1618	sub ready {
1288	$_[0]{_ae_sent}	1619	$_[0]{_ae_sent}
1289	}	1620	}
1290		1621
1291	sub _wait {	1622	sub _wait {
		1623	$WAITING
		1624	and !$_[0]{_ae_sent}
		1625	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1626
		1627	local $WAITING = 1;
1292	AnyEvent->one_event while !$_[0]{_ae_sent};	1628	AnyEvent->one_event while !$_[0]{_ae_sent};
1293	}	1629	}
1294		1630
1295	sub recv {	1631	sub recv {
1296	$_[0]->_wait;	1632	$_[0]->_wait;
…		…
1298	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1634	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1299	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1635	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1300	}	1636	}
1301		1637
1302	sub cb {	1638	sub cb {
1303	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1639	my $cv = shift;
		1640
		1641	@_
		1642	and $cv->{_ae_cb} = shift
		1643	and $cv->{_ae_sent}
		1644	and (delete $cv->{_ae_cb})->($cv);
1304	$_[0]{_ae_cb}	1645	$cv->{_ae_cb}
1305	}	1646	}
1306		1647
1307	sub begin {	1648	sub begin {
1308	++$_[0]{_ae_counter};	1649	++$_[0]{_ae_counter};
1309	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1650	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1315	}	1656	}
1316		1657
1317	# undocumented/compatibility with pre-3.4	1658	# undocumented/compatibility with pre-3.4
1318	*broadcast = \&send;	1659	*broadcast = \&send;
1319	*wait = \&_wait;	1660	*wait = \&_wait;
		1661
		1662	#############################################################################
		1663	# "new" API, currently only emulation of it
		1664	#############################################################################
		1665
		1666	package AE;
		1667
		1668	sub io($$$) {
		1669	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1670	}
		1671
		1672	sub timer($$$) {
		1673	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2]);
		1674	}
		1675
		1676	sub signal($$) {
		1677	AnyEvent->signal (signal => $_[0], cb => $_[1]);
		1678	}
		1679
		1680	sub child($$) {
		1681	AnyEvent->child (pid => $_[0], cb => $_[1]);
		1682	}
		1683
		1684	sub idle($) {
		1685	AnyEvent->idle (cb => $_[0]);
		1686	}
		1687
		1688	sub cv() {
		1689	AnyEvent->condvar
		1690	}
		1691
		1692	sub now() {
		1693	AnyEvent->now
		1694	}
		1695
		1696	sub now_update() {
		1697	AnyEvent->now_update
		1698	}
		1699
		1700	sub time() {
		1701	AnyEvent->time
		1702	}
1320		1703
1321	=head1 ERROR AND EXCEPTION HANDLING	1704	=head1 ERROR AND EXCEPTION HANDLING
1322		1705
1323	In general, AnyEvent does not do any error handling - it relies on the	1706	In general, AnyEvent does not do any error handling - it relies on the
1324	caller to do that if required. The L<AnyEvent::Strict> module (see also	1707	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1337	so on.	1720	so on.
1338		1721
1339	=head1 ENVIRONMENT VARIABLES	1722	=head1 ENVIRONMENT VARIABLES
1340		1723
1341	The following environment variables are used by this module or its	1724	The following environment variables are used by this module or its
1342	submodules:	1725	submodules.
		1726
		1727	Note that AnyEvent will remove I<all> environment variables starting with
		1728	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1729	enabled.
1343		1730
1344	=over 4	1731	=over 4
1345		1732
1346	=item C<PERL_ANYEVENT_VERBOSE>	1733	=item C<PERL_ANYEVENT_VERBOSE>
1347		1734
…		…
1354	C<PERL_ANYEVENT_MODEL>.	1741	C<PERL_ANYEVENT_MODEL>.
1355		1742
1356	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1743	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1357	model it chooses.	1744	model it chooses.
1358		1745
		1746	When set to C<8> or higher, then AnyEvent will report extra information on
		1747	which optional modules it loads and how it implements certain features.
		1748
1359	=item C<PERL_ANYEVENT_STRICT>	1749	=item C<PERL_ANYEVENT_STRICT>
1360		1750
1361	AnyEvent does not do much argument checking by default, as thorough	1751	AnyEvent does not do much argument checking by default, as thorough
1362	argument checking is very costly. Setting this variable to a true value	1752	argument checking is very costly. Setting this variable to a true value
1363	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1753	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1364	check the arguments passed to most method calls. If it finds any problems	1754	check the arguments passed to most method calls. If it finds any problems,
1365	it will croak.	1755	it will croak.
1366		1756
1367	In other words, enables "strict" mode.	1757	In other words, enables "strict" mode.
1368		1758
1369	Unlike C<use strict>, it is definitely recommended ot keep it off in	1759	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1370	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1760	>>, it is definitely recommended to keep it off in production. Keeping
1371	developing programs can be very useful, however.	1761	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1762	can be very useful, however.
1372		1763
1373	=item C<PERL_ANYEVENT_MODEL>	1764	=item C<PERL_ANYEVENT_MODEL>
1374		1765
1375	This can be used to specify the event model to be used by AnyEvent, before	1766	This can be used to specify the event model to be used by AnyEvent, before
1376	auto detection and -probing kicks in. It must be a string consisting	1767	auto detection and -probing kicks in. It must be a string consisting
…		…
1419		1810
1420	=item C<PERL_ANYEVENT_MAX_FORKS>	1811	=item C<PERL_ANYEVENT_MAX_FORKS>
1421		1812
1422	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1813	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1423	will create in parallel.	1814	will create in parallel.
		1815
		1816	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1817
		1818	The default value for the C<max_outstanding> parameter for the default DNS
		1819	resolver - this is the maximum number of parallel DNS requests that are
		1820	sent to the DNS server.
		1821
		1822	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1823
		1824	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1825	configuration) in the default resolver. When set to the empty string, no
		1826	default config will be used.
		1827
		1828	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1829
		1830	When neither C<ca_file> nor C<ca_path> was specified during
		1831	L<AnyEvent::TLS> context creation, and either of these environment
		1832	variables exist, they will be used to specify CA certificate locations
		1833	instead of a system-dependent default.
		1834
		1835	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1836
		1837	When these are set to C<1>, then the respective modules are not
		1838	loaded. Mostly good for testing AnyEvent itself.
1424		1839
1425	=back	1840	=back
1426		1841
1427	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1842	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1428		1843
…		…
1673	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2088	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1674	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2089	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1675	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2090	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1676	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2091	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1677	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2092	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		2093	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		2094	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1678	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2095	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1679	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2096	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1680	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2097	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1681	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2098	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1682		2099
…		…
1711	performance becomes really bad with lots of file descriptors (and few of	2128	performance becomes really bad with lots of file descriptors (and few of
1712	them active), of course, but this was not subject of this benchmark.	2129	them active), of course, but this was not subject of this benchmark.
1713		2130
1714	The C<Event> module has a relatively high setup and callback invocation	2131	The C<Event> module has a relatively high setup and callback invocation
1715	cost, but overall scores in on the third place.	2132	cost, but overall scores in on the third place.
		2133
		2134	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2135	when using its pure perl backend.
1716		2136
1717	C<Glib>'s memory usage is quite a bit higher, but it features a	2137	C<Glib>'s memory usage is quite a bit higher, but it features a
1718	faster callback invocation and overall ends up in the same class as	2138	faster callback invocation and overall ends up in the same class as
1719	C<Event>. However, Glib scales extremely badly, doubling the number of	2139	C<Event>. However, Glib scales extremely badly, doubling the number of
1720	watchers increases the processing time by more than a factor of four,	2140	watchers increases the processing time by more than a factor of four,
…		…
1798	it to another server. This includes deleting the old timeout and creating	2218	it to another server. This includes deleting the old timeout and creating
1799	a new one that moves the timeout into the future.	2219	a new one that moves the timeout into the future.
1800		2220
1801	=head3 Results	2221	=head3 Results
1802		2222
1803	name sockets create request	2223	name sockets create request
1804	EV 20000 69.01 11.16	2224	EV 20000 69.01 11.16
1805	Perl 20000 73.32 35.87	2225	Perl 20000 73.32 35.87
		2226	IOAsync 20000 157.00 98.14 epoll
		2227	IOAsync 20000 159.31 616.06 poll
1806	Event 20000 212.62 257.32	2228	Event 20000 212.62 257.32
1807	Glib 20000 651.16 1896.30	2229	Glib 20000 651.16 1896.30
1808	POE 20000 349.67 12317.24 uses POE::Loop::Event	2230	POE 20000 349.67 12317.24 uses POE::Loop::Event
1809		2231
1810	=head3 Discussion	2232	=head3 Discussion
1811		2233
1812	This benchmark I<does> measure scalability and overall performance of the	2234	This benchmark I<does> measure scalability and overall performance of the
1813	particular event loop.	2235	particular event loop.
…		…
1815	EV is again fastest. Since it is using epoll on my system, the setup time	2237	EV is again fastest. Since it is using epoll on my system, the setup time
1816	is relatively high, though.	2238	is relatively high, though.
1817		2239
1818	Perl surprisingly comes second. It is much faster than the C-based event	2240	Perl surprisingly comes second. It is much faster than the C-based event
1819	loops Event and Glib.	2241	loops Event and Glib.
		2242
		2243	IO::Async performs very well when using its epoll backend, and still quite
		2244	good compared to Glib when using its pure perl backend.
1820		2245
1821	Event suffers from high setup time as well (look at its code and you will	2246	Event suffers from high setup time as well (look at its code and you will
1822	understand why). Callback invocation also has a high overhead compared to	2247	understand why). Callback invocation also has a high overhead compared to
1823	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2248	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1824	uses select or poll in basically all documented configurations.	2249	uses select or poll in basically all documented configurations.
…		…
1887	=item * C-based event loops perform very well with small number of	2312	=item * C-based event loops perform very well with small number of
1888	watchers, as the management overhead dominates.	2313	watchers, as the management overhead dominates.
1889		2314
1890	=back	2315	=back
1891		2316
		2317	=head2 THE IO::Lambda BENCHMARK
		2318
		2319	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2320	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2321	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2322	shouldn't come as a surprise to anybody). As such, the benchmark is
		2323	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2324	very optimal. But how would AnyEvent compare when used without the extra
		2325	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2326
		2327	The benchmark itself creates an echo-server, and then, for 500 times,
		2328	connects to the echo server, sends a line, waits for the reply, and then
		2329	creates the next connection. This is a rather bad benchmark, as it doesn't
		2330	test the efficiency of the framework or much non-blocking I/O, but it is a
		2331	benchmark nevertheless.
		2332
		2333	name runtime
		2334	Lambda/select 0.330 sec
		2335	+ optimized 0.122 sec
		2336	Lambda/AnyEvent 0.327 sec
		2337	+ optimized 0.138 sec
		2338	Raw sockets/select 0.077 sec
		2339	POE/select, components 0.662 sec
		2340	POE/select, raw sockets 0.226 sec
		2341	POE/select, optimized 0.404 sec
		2342
		2343	AnyEvent/select/nb 0.085 sec
		2344	AnyEvent/EV/nb 0.068 sec
		2345	+state machine 0.134 sec
		2346
		2347	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2348	benchmarks actually make blocking connects and use 100% blocking I/O,
		2349	defeating the purpose of an event-based solution. All of the newly
		2350	written AnyEvent benchmarks use 100% non-blocking connects (using
		2351	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2352	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2353	generally require a lot more bookkeeping and event handling than blocking
		2354	connects (which involve a single syscall only).
		2355
		2356	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2357	offers similar expressive power as POE and IO::Lambda, using conventional
		2358	Perl syntax. This means that both the echo server and the client are 100%
		2359	non-blocking, further placing it at a disadvantage.
		2360
		2361	As you can see, the AnyEvent + EV combination even beats the
		2362	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2363	backend easily beats IO::Lambda and POE.
		2364
		2365	And even the 100% non-blocking version written using the high-level (and
		2366	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2367	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2368	in a non-blocking way.
		2369
		2370	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2371	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2372	part of the IO::lambda distribution and were used without any changes.
		2373
1892		2374
1893	=head1 SIGNALS	2375	=head1 SIGNALS
1894		2376
1895	AnyEvent currently installs handlers for these signals:	2377	AnyEvent currently installs handlers for these signals:
1896		2378
…		…
1899	=item SIGCHLD	2381	=item SIGCHLD
1900		2382
1901	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2383	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1902	emulation for event loops that do not support them natively. Also, some	2384	emulation for event loops that do not support them natively. Also, some
1903	event loops install a similar handler.	2385	event loops install a similar handler.
		2386
		2387	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2388	AnyEvent will reset it to default, to avoid losing child exit statuses.
1904		2389
1905	=item SIGPIPE	2390	=item SIGPIPE
1906		2391
1907	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2392	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1908	when AnyEvent gets loaded.	2393	when AnyEvent gets loaded.
…		…
1920		2405
1921	=back	2406	=back
1922		2407
1923	=cut	2408	=cut
1924		2409
		2410	undef $SIG{CHLD}
		2411	if $SIG{CHLD} eq 'IGNORE';
		2412
1925	$SIG{PIPE} = sub { }	2413	$SIG{PIPE} = sub { }
1926	unless defined $SIG{PIPE};	2414	unless defined $SIG{PIPE};
		2415
		2416	=head1 RECOMMENDED/OPTIONAL MODULES
		2417
		2418	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2419	it's built-in modules) are required to use it.
		2420
		2421	That does not mean that AnyEvent won't take advantage of some additional
		2422	modules if they are installed.
		2423
		2424	This section epxlains which additional modules will be used, and how they
		2425	affect AnyEvent's operetion.
		2426
		2427	=over 4
		2428
		2429	=item L<Async::Interrupt>
		2430
		2431	This slightly arcane module is used to implement fast signal handling: To
		2432	my knowledge, there is no way to do completely race-free and quick
		2433	signal handling in pure perl. To ensure that signals still get
		2434	delivered, AnyEvent will start an interval timer to wake up perl (and
		2435	catch the signals) with some delay (default is 10 seconds, look for
		2436	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2437
		2438	If this module is available, then it will be used to implement signal
		2439	catching, which means that signals will not be delayed, and the event loop
		2440	will not be interrupted regularly, which is more efficient (And good for
		2441	battery life on laptops).
		2442
		2443	This affects not just the pure-perl event loop, but also other event loops
		2444	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2445
		2446	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2447	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2448	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2449	does nothing for those backends.
		2450
		2451	=item L<EV>
		2452
		2453	This module isn't really "optional", as it is simply one of the backend
		2454	event loops that AnyEvent can use. However, it is simply the best event
		2455	loop available in terms of features, speed and stability: It supports
		2456	the AnyEvent API optimally, implements all the watcher types in XS, does
		2457	automatic timer adjustments even when no monotonic clock is available,
		2458	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2459	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2460	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2461
		2462	=item L<Guard>
		2463
		2464	The guard module, when used, will be used to implement
		2465	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2466	lot less memory), but otherwise doesn't affect guard operation much. It is
		2467	purely used for performance.
		2468
		2469	=item L<JSON> and L<JSON::XS>
		2470
		2471	This module is required when you want to read or write JSON data via
		2472	L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2473	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2474
		2475	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2476	installed.
		2477
		2478	=item L<Net::SSLeay>
		2479
		2480	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2481	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2482	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2483
		2484	=item L<Time::HiRes>
		2485
		2486	This module is part of perl since release 5.008. It will be used when the
		2487	chosen event library does not come with a timing source on it's own. The
		2488	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2489	try to use a monotonic clock for timing stability.
		2490
		2491	=back
1927		2492
1928		2493
1929	=head1 FORK	2494	=head1 FORK
1930		2495
1931	Most event libraries are not fork-safe. The ones who are usually are	2496	Most event libraries are not fork-safe. The ones who are usually are
1932	because they rely on inefficient but fork-safe C<select> or C<poll>	2497	because they rely on inefficient but fork-safe C<select> or C<poll>
1933	calls. Only L<EV> is fully fork-aware.	2498	calls. Only L<EV> is fully fork-aware.
1934		2499
1935	If you have to fork, you must either do so I<before> creating your first	2500	If you have to fork, you must either do so I<before> creating your first
1936	watcher OR you must not use AnyEvent at all in the child.	2501	watcher OR you must not use AnyEvent at all in the child OR you must do
		2502	something completely out of the scope of AnyEvent.
1937		2503
1938		2504
1939	=head1 SECURITY CONSIDERATIONS	2505	=head1 SECURITY CONSIDERATIONS
1940		2506
1941	AnyEvent can be forced to load any event model via	2507	AnyEvent can be forced to load any event model via
…		…
1955	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2521	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1956	be used to probe what backend is used and gain other information (which is	2522	be used to probe what backend is used and gain other information (which is
1957	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2523	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1958	$ENV{PERL_ANYEVENT_STRICT}.	2524	$ENV{PERL_ANYEVENT_STRICT}.
1959		2525
		2526	Note that AnyEvent will remove I<all> environment variables starting with
		2527	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2528	enabled.
		2529
1960		2530
1961	=head1 BUGS	2531	=head1 BUGS
1962		2532
1963	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2533	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1964	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2534	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
…		…
1975	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2545	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1976		2546
1977	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2547	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1978	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2548	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1979	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2549	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1980	L<AnyEvent::Impl::POE>.	2550	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1981		2551
1982	Non-blocking file handles, sockets, TCP clients and	2552	Non-blocking file handles, sockets, TCP clients and
1983	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2553	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1984		2554
1985	Asynchronous DNS: L<AnyEvent::DNS>.	2555	Asynchronous DNS: L<AnyEvent::DNS>.
1986		2556
1987	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2557	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2558	L<Coro::Event>,
1988		2559
1989	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2560	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2561	L<AnyEvent::HTTP>.
1990		2562
1991		2563
1992	=head1 AUTHOR	2564	=head1 AUTHOR
1993		2565
1994	Marc Lehmann <schmorp@schmorp.de>	2566	Marc Lehmann <schmorp@schmorp.de>

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