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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 fall back to its own
		812	pure-perl implementation, which is available everywhere as it comes with
		813	AnyEvent itself.
		814
		815	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		816	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		817
		818	=item Backends that are transparently being picked up when they are used.
		819
		820	These will be used when they are currently loaded when the first watcher
		821	is created, in which case it is assumed that the application is using
		822	them. This means that AnyEvent will automatically pick the right backend
		823	when the main program loads an event module before anything starts to
		824	create watchers. Nothing special needs to be done by the main program.
		825
		826	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		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 = 4.92;
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::],
965	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1156	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
966	# everything below here will not be autoprobed	1157	# everything below here will not (normally) be autoprobed
967	# as the pureperl backend should work everywhere	1158	# as the pureperl backend should work everywhere
968	# and is usually faster	1159	# and is usually faster
		1160	[Event:: => AnyEvent::Impl::Event::, 1],
		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($$$$) {	1278	sub _dupfh($$;$$) {
1078	my ($poll, $fh, $r, $w) = @_;	1279	my ($poll, $fh, $r, $w) = @_;
1079		1280
1080	# cygwin requires the fh mode to be matching, unix doesn't	1281	# cygwin requires the fh mode to be matching, unix doesn't
1081	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1282	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1082	: $poll eq "w" ? ($w, ">")
1083	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1084		1283
1085	open my $fh2, "$mode&" . fileno $fh	1284	open my $fh2, $mode, $fh
1086	or die "cannot dup() filehandle: $!,";	1285	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1087		1286
1088	# we assume CLOEXEC is already set by perl in all important cases	1287	# we assume CLOEXEC is already set by perl in all important cases
1089		1288
1090	($fh2, $rw)	1289	($fh2, $rw)
1091	}	1290	}
1092		1291
		1292	#############################################################################
		1293	# "new" API, currently only emulation of it
		1294	#############################################################################
		1295
		1296	package AE;
		1297
		1298	our $VERSION = $AnyEvent::VERSION;
		1299
		1300	sub io($$$) {
		1301	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1302	}
		1303
		1304	sub timer($$$) {
		1305	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2]);
		1306	}
		1307
		1308	sub signal($$) {
		1309	AnyEvent->signal (signal => $_[0], cb => $_[1]);
		1310	}
		1311
		1312	sub child($$) {
		1313	AnyEvent->child (pid => $_[0], cb => $_[1]);
		1314	}
		1315
		1316	sub idle($) {
		1317	AnyEvent->idle (cb => $_[0]);
		1318	}
		1319
		1320	sub cv(;&) {
		1321	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1322	}
		1323
		1324	sub now() {
		1325	AnyEvent->now
		1326	}
		1327
		1328	sub now_update() {
		1329	AnyEvent->now_update
		1330	}
		1331
		1332	sub time() {
		1333	AnyEvent->time
		1334	}
		1335
1093	package AnyEvent::Base;	1336	package AnyEvent::Base;
1094		1337
1095	# default implementations for many methods	1338	# default implementations for many methods
1096		1339
1097	BEGIN {	1340	sub _time {
		1341	# probe for availability of Time::HiRes
1098	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1342	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1343	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1099	*_time = \&Time::HiRes::time;	1344	*_time = \&Time::HiRes::time;
1100	# if (eval "use POSIX (); (POSIX::times())...	1345	# if (eval "use POSIX (); (POSIX::times())...
1101	} else {	1346	} else {
		1347	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1102	*_time = sub { time }; # epic fail	1348	*_time = sub { time }; # epic fail
1103	}	1349	}
		1350
		1351	&_time
1104	}	1352	}
1105		1353
1106	sub time { _time }	1354	sub time { _time }
1107	sub now { _time }	1355	sub now { _time }
1108	sub now_update { }	1356	sub now_update { }
…		…
1113	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1361	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1114	}	1362	}
1115		1363
1116	# default implementation for ->signal	1364	# default implementation for ->signal
1117		1365
		1366	our $HAVE_ASYNC_INTERRUPT;
		1367
		1368	sub _have_async_interrupt() {
		1369	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1370	&& eval "use Async::Interrupt 1.0 (); 1")
		1371	unless defined $HAVE_ASYNC_INTERRUPT;
		1372
		1373	$HAVE_ASYNC_INTERRUPT
		1374	}
		1375
1118	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1376	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1377	our (%SIG_ASY, %SIG_ASY_W);
		1378	our ($SIG_COUNT, $SIG_TW);
1119		1379
1120	sub _signal_exec {	1380	sub _signal_exec {
		1381	$HAVE_ASYNC_INTERRUPT
		1382	? $SIGPIPE_R->drain
1121	sysread $SIGPIPE_R, my $dummy, 4;	1383	: sysread $SIGPIPE_R, my $dummy, 9;
1122		1384
1123	while (%SIG_EV) {	1385	while (%SIG_EV) {
1124	for (keys %SIG_EV) {	1386	for (keys %SIG_EV) {
1125	delete $SIG_EV{$_};	1387	delete $SIG_EV{$_};
1126	$_->() for values %{ $SIG_CB{$_} || {} };	1388	$_->() for values %{ $SIG_CB{$_} || {} };
1127	}	1389	}
1128	}	1390	}
1129	}	1391	}
1130		1392
		1393	# install a dummy wakeup watcher to reduce signal catching latency
		1394	sub _sig_add() {
		1395	unless ($SIG_COUNT++) {
		1396	# try to align timer on a full-second boundary, if possible
		1397	my $NOW = AE::now;
		1398
		1399	$SIG_TW = AE::timer
		1400	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1401	$MAX_SIGNAL_LATENCY,
		1402	sub { } # just for the PERL_ASYNC_CHECK
		1403	;
		1404	}
		1405	}
		1406
		1407	sub _sig_del {
		1408	undef $SIG_TW
		1409	unless --$SIG_COUNT;
		1410	}
		1411
		1412	our $_sig_name_init; $_sig_name_init = sub {
		1413	eval q{ # poor man's autoloading
		1414	undef $_sig_name_init;
		1415
		1416	if (_have_async_interrupt) {
		1417	*sig2num = \&Async::Interrupt::sig2num;
		1418	*sig2name = \&Async::Interrupt::sig2name;
		1419	} else {
		1420	require Config;
		1421
		1422	my %signame2num;
		1423	@signame2num{ split ' ', $Config::Config{sig_name} }
		1424	= split ' ', $Config::Config{sig_num};
		1425
		1426	my @signum2name;
		1427	@signum2name[values %signame2num] = keys %signame2num;
		1428
		1429	*sig2num = sub($) {
		1430	$_[0] > 0 ? shift : $signame2num{+shift}
		1431	};
		1432	*sig2name = sub ($) {
		1433	$_[0] > 0 ? $signum2name[+shift] : shift
		1434	};
		1435	}
		1436	};
		1437	die if $@;
		1438	};
		1439
		1440	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1441	sub sig2name($) { &$_sig_name_init; &sig2name }
		1442
1131	sub signal {	1443	sub signal {
1132	my (undef, %arg) = @_;	1444	eval q{ # poor man's autoloading {}
		1445	# probe for availability of Async::Interrupt
		1446	if (_have_async_interrupt) {
		1447	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1133		1448
1134	unless ($SIGPIPE_R) {	1449	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1135	require Fcntl;	1450	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1136		1451
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 {	1452	} else {
		1453	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1454
		1455	require Fcntl;
		1456
		1457	if (AnyEvent::WIN32) {
		1458	require AnyEvent::Util;
		1459
		1460	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1461	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1462	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1463	} else {
1144	pipe $SIGPIPE_R, $SIGPIPE_W;	1464	pipe $SIGPIPE_R, $SIGPIPE_W;
1145	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1465	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	1466	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1147		1467
1148	# not strictly required, as $^F is normally 2, but let's make sure...	1468	# not strictly required, as $^F is normally 2, but let's make sure...
1149	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1469	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1150	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1470	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1471	}
		1472
		1473	$SIGPIPE_R
		1474	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1475
		1476	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1151	}	1477	}
1152		1478
1153	$SIGPIPE_R	1479	*signal = sub {
1154	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1480	my (undef, %arg) = @_;
1155		1481
1156	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1157	}
1158
1159	my $signal = uc $arg{signal}	1482	my $signal = uc $arg{signal}
1160	or Carp::croak "required option 'signal' is missing";	1483	or Carp::croak "required option 'signal' is missing";
1161		1484
		1485	if ($HAVE_ASYNC_INTERRUPT) {
		1486	# async::interrupt
		1487
		1488	$signal = sig2num $signal;
1162	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1489	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1490
		1491	$SIG_ASY{$signal} ||= new Async::Interrupt
		1492	cb => sub { undef $SIG_EV{$signal} },
		1493	signal => $signal,
		1494	pipe => [$SIGPIPE_R->filenos],
		1495	pipe_autodrain => 0,
		1496	;
		1497
		1498	} else {
		1499	# pure perl
		1500
		1501	# AE::Util has been loaded in signal
		1502	$signal = sig2name $signal;
		1503	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1504
1163	$SIG{$signal} ||= sub {	1505	$SIG{$signal} ||= sub {
1164	local $!;	1506	local $!;
1165	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1507	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1166	undef $SIG_EV{$signal};	1508	undef $SIG_EV{$signal};
		1509	};
		1510
		1511	# can't do signal processing without introducing races in pure perl,
		1512	# so limit the signal latency.
		1513	_sig_add;
		1514	}
		1515
		1516	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1517	};
		1518
		1519	*AnyEvent::Base::signal::DESTROY = sub {
		1520	my ($signal, $cb) = @{$_[0]};
		1521
		1522	_sig_del;
		1523
		1524	delete $SIG_CB{$signal}{$cb};
		1525
		1526	$HAVE_ASYNC_INTERRUPT
		1527	? delete $SIG_ASY{$signal}
		1528	: # delete doesn't work with older perls - they then
		1529	# print weird messages, or just unconditionally exit
		1530	# instead of getting the default action.
		1531	undef $SIG{$signal}
		1532	unless keys %{ $SIG_CB{$signal} };
		1533	};
1167	};	1534	};
1168		1535	die if $@;
1169	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1536	&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	}	1537	}
1182		1538
1183	# default implementation for ->child	1539	# default implementation for ->child
1184		1540
1185	our %PID_CB;	1541	our %PID_CB;
1186	our $CHLD_W;	1542	our $CHLD_W;
1187	our $CHLD_DELAY_W;	1543	our $CHLD_DELAY_W;
1188	our $WNOHANG;	1544	our $WNOHANG;
1189		1545
		1546	sub _emit_childstatus($$) {
		1547	my (undef, $rpid, $rstatus) = @_;
		1548
		1549	$_->($rpid, $rstatus)
		1550	for values %{ $PID_CB{$rpid} || {} },
		1551	values %{ $PID_CB{0} || {} };
		1552	}
		1553
1190	sub _sigchld {	1554	sub _sigchld {
		1555	my $pid;
		1556
		1557	AnyEvent->_emit_childstatus ($pid, $?)
1191	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1558	while ($pid = waitpid -1, $WNOHANG) > 0;
1192	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),
1193	(values %{ $PID_CB{0} || {} });
1194	}
1195	}	1559	}
1196		1560
1197	sub child {	1561	sub child {
1198	my (undef, %arg) = @_;	1562	my (undef, %arg) = @_;
1199		1563
1200	defined (my $pid = $arg{pid} + 0)	1564	defined (my $pid = $arg{pid} + 0)
1201	or Carp::croak "required option 'pid' is missing";	1565	or Carp::croak "required option 'pid' is missing";
1202		1566
1203	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1567	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1204		1568
		1569	# WNOHANG is almost cetrainly 1 everywhere
		1570	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1571	? 1
1205	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1572	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1206		1573
1207	unless ($CHLD_W) {	1574	unless ($CHLD_W) {
1208	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1575	$CHLD_W = AE::signal CHLD => \&_sigchld;
1209	# child could be a zombie already, so make at least one round	1576	# child could be a zombie already, so make at least one round
1210	&_sigchld;	1577	&_sigchld;
1211	}	1578	}
1212		1579
1213	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1580	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
…		…
1239	# never use more then 50% of the time for the idle watcher,	1606	# never use more then 50% of the time for the idle watcher,
1240	# within some limits	1607	# within some limits
1241	$w = 0.0001 if $w < 0.0001;	1608	$w = 0.0001 if $w < 0.0001;
1242	$w = 5 if $w > 5;	1609	$w = 5 if $w > 5;
1243		1610
1244	$w = AnyEvent->timer (after => $w, cb => $rcb);	1611	$w = AE::timer $w, 0, $rcb;
1245	} else {	1612	} else {
1246	# clean up...	1613	# clean up...
1247	undef $w;	1614	undef $w;
1248	undef $rcb;	1615	undef $rcb;
1249	}	1616	}
1250	};	1617	};
1251		1618
1252	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1619	$w = AE::timer 0.05, 0, $rcb;
1253		1620
1254	bless \\$cb, "AnyEvent::Base::idle"	1621	bless \\$cb, "AnyEvent::Base::idle"
1255	}	1622	}
1256		1623
1257	sub AnyEvent::Base::idle::DESTROY {	1624	sub AnyEvent::Base::idle::DESTROY {
…		…
1262		1629
1263	our @ISA = AnyEvent::CondVar::Base::;	1630	our @ISA = AnyEvent::CondVar::Base::;
1264		1631
1265	package AnyEvent::CondVar::Base;	1632	package AnyEvent::CondVar::Base;
1266		1633
1267	use overload	1634	#use overload
1268	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1635	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1269	fallback => 1;	1636	# fallback => 1;
		1637
		1638	# save 300+ kilobytes by dirtily hardcoding overloading
		1639	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1640	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1641	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1642	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1643
		1644	our $WAITING;
1270		1645
1271	sub _send {	1646	sub _send {
1272	# nop	1647	# nop
1273	}	1648	}
1274		1649
…		…
1287	sub ready {	1662	sub ready {
1288	$_[0]{_ae_sent}	1663	$_[0]{_ae_sent}
1289	}	1664	}
1290		1665
1291	sub _wait {	1666	sub _wait {
		1667	$WAITING
		1668	and !$_[0]{_ae_sent}
		1669	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1670
		1671	local $WAITING = 1;
1292	AnyEvent->one_event while !$_[0]{_ae_sent};	1672	AnyEvent->one_event while !$_[0]{_ae_sent};
1293	}	1673	}
1294		1674
1295	sub recv {	1675	sub recv {
1296	$_[0]->_wait;	1676	$_[0]->_wait;
…		…
1298	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1678	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1299	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1679	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1300	}	1680	}
1301		1681
1302	sub cb {	1682	sub cb {
1303	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1683	my $cv = shift;
		1684
		1685	@_
		1686	and $cv->{_ae_cb} = shift
		1687	and $cv->{_ae_sent}
		1688	and (delete $cv->{_ae_cb})->($cv);
		1689
1304	$_[0]{_ae_cb}	1690	$cv->{_ae_cb}
1305	}	1691	}
1306		1692
1307	sub begin {	1693	sub begin {
1308	++$_[0]{_ae_counter};	1694	++$_[0]{_ae_counter};
1309	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1695	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1337	so on.	1723	so on.
1338		1724
1339	=head1 ENVIRONMENT VARIABLES	1725	=head1 ENVIRONMENT VARIABLES
1340		1726
1341	The following environment variables are used by this module or its	1727	The following environment variables are used by this module or its
1342	submodules:	1728	submodules.
		1729
		1730	Note that AnyEvent will remove I<all> environment variables starting with
		1731	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1732	enabled.
1343		1733
1344	=over 4	1734	=over 4
1345		1735
1346	=item C<PERL_ANYEVENT_VERBOSE>	1736	=item C<PERL_ANYEVENT_VERBOSE>
1347		1737
…		…
1354	C<PERL_ANYEVENT_MODEL>.	1744	C<PERL_ANYEVENT_MODEL>.
1355		1745
1356	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1746	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1357	model it chooses.	1747	model it chooses.
1358		1748
		1749	When set to C<8> or higher, then AnyEvent will report extra information on
		1750	which optional modules it loads and how it implements certain features.
		1751
1359	=item C<PERL_ANYEVENT_STRICT>	1752	=item C<PERL_ANYEVENT_STRICT>
1360		1753
1361	AnyEvent does not do much argument checking by default, as thorough	1754	AnyEvent does not do much argument checking by default, as thorough
1362	argument checking is very costly. Setting this variable to a true value	1755	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	1756	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	1757	check the arguments passed to most method calls. If it finds any problems,
1365	it will croak.	1758	it will croak.
1366		1759
1367	In other words, enables "strict" mode.	1760	In other words, enables "strict" mode.
1368		1761
1369	Unlike C<use strict>, it is definitely recommended ot keep it off in	1762	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	1763	>>, it is definitely recommended to keep it off in production. Keeping
1371	developing programs can be very useful, however.	1764	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1765	can be very useful, however.
1372		1766
1373	=item C<PERL_ANYEVENT_MODEL>	1767	=item C<PERL_ANYEVENT_MODEL>
1374		1768
1375	This can be used to specify the event model to be used by AnyEvent, before	1769	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	1770	auto detection and -probing kicks in. It must be a string consisting
…		…
1419		1813
1420	=item C<PERL_ANYEVENT_MAX_FORKS>	1814	=item C<PERL_ANYEVENT_MAX_FORKS>
1421		1815
1422	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1816	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1423	will create in parallel.	1817	will create in parallel.
		1818
		1819	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1820
		1821	The default value for the C<max_outstanding> parameter for the default DNS
		1822	resolver - this is the maximum number of parallel DNS requests that are
		1823	sent to the DNS server.
		1824
		1825	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1826
		1827	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1828	configuration) in the default resolver. When set to the empty string, no
		1829	default config will be used.
		1830
		1831	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1832
		1833	When neither C<ca_file> nor C<ca_path> was specified during
		1834	L<AnyEvent::TLS> context creation, and either of these environment
		1835	variables exist, they will be used to specify CA certificate locations
		1836	instead of a system-dependent default.
		1837
		1838	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1839
		1840	When these are set to C<1>, then the respective modules are not
		1841	loaded. Mostly good for testing AnyEvent itself.
1424		1842
1425	=back	1843	=back
1426		1844
1427	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1845	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1428		1846
…		…
1673	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2091	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	2092	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	2093	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	2094	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	2095	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		2096	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		2097	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	2098	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	2099	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	2100	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	2101	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1682		2102
…		…
1711	performance becomes really bad with lots of file descriptors (and few of	2131	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.	2132	them active), of course, but this was not subject of this benchmark.
1713		2133
1714	The C<Event> module has a relatively high setup and callback invocation	2134	The C<Event> module has a relatively high setup and callback invocation
1715	cost, but overall scores in on the third place.	2135	cost, but overall scores in on the third place.
		2136
		2137	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2138	when using its pure perl backend.
1716		2139
1717	C<Glib>'s memory usage is quite a bit higher, but it features a	2140	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	2141	faster callback invocation and overall ends up in the same class as
1719	C<Event>. However, Glib scales extremely badly, doubling the number of	2142	C<Event>. However, Glib scales extremely badly, doubling the number of
1720	watchers increases the processing time by more than a factor of four,	2143	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	2221	it to another server. This includes deleting the old timeout and creating
1799	a new one that moves the timeout into the future.	2222	a new one that moves the timeout into the future.
1800		2223
1801	=head3 Results	2224	=head3 Results
1802		2225
1803	name sockets create request	2226	name sockets create request
1804	EV 20000 69.01 11.16	2227	EV 20000 69.01 11.16
1805	Perl 20000 73.32 35.87	2228	Perl 20000 73.32 35.87
		2229	IOAsync 20000 157.00 98.14 epoll
		2230	IOAsync 20000 159.31 616.06 poll
1806	Event 20000 212.62 257.32	2231	Event 20000 212.62 257.32
1807	Glib 20000 651.16 1896.30	2232	Glib 20000 651.16 1896.30
1808	POE 20000 349.67 12317.24 uses POE::Loop::Event	2233	POE 20000 349.67 12317.24 uses POE::Loop::Event
1809		2234
1810	=head3 Discussion	2235	=head3 Discussion
1811		2236
1812	This benchmark I<does> measure scalability and overall performance of the	2237	This benchmark I<does> measure scalability and overall performance of the
1813	particular event loop.	2238	particular event loop.
…		…
1815	EV is again fastest. Since it is using epoll on my system, the setup time	2240	EV is again fastest. Since it is using epoll on my system, the setup time
1816	is relatively high, though.	2241	is relatively high, though.
1817		2242
1818	Perl surprisingly comes second. It is much faster than the C-based event	2243	Perl surprisingly comes second. It is much faster than the C-based event
1819	loops Event and Glib.	2244	loops Event and Glib.
		2245
		2246	IO::Async performs very well when using its epoll backend, and still quite
		2247	good compared to Glib when using its pure perl backend.
1820		2248
1821	Event suffers from high setup time as well (look at its code and you will	2249	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	2250	understand why). Callback invocation also has a high overhead compared to
1823	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2251	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1824	uses select or poll in basically all documented configurations.	2252	uses select or poll in basically all documented configurations.
…		…
1887	=item * C-based event loops perform very well with small number of	2315	=item * C-based event loops perform very well with small number of
1888	watchers, as the management overhead dominates.	2316	watchers, as the management overhead dominates.
1889		2317
1890	=back	2318	=back
1891		2319
		2320	=head2 THE IO::Lambda BENCHMARK
		2321
		2322	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2323	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2324	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2325	shouldn't come as a surprise to anybody). As such, the benchmark is
		2326	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2327	very optimal. But how would AnyEvent compare when used without the extra
		2328	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2329
		2330	The benchmark itself creates an echo-server, and then, for 500 times,
		2331	connects to the echo server, sends a line, waits for the reply, and then
		2332	creates the next connection. This is a rather bad benchmark, as it doesn't
		2333	test the efficiency of the framework or much non-blocking I/O, but it is a
		2334	benchmark nevertheless.
		2335
		2336	name runtime
		2337	Lambda/select 0.330 sec
		2338	+ optimized 0.122 sec
		2339	Lambda/AnyEvent 0.327 sec
		2340	+ optimized 0.138 sec
		2341	Raw sockets/select 0.077 sec
		2342	POE/select, components 0.662 sec
		2343	POE/select, raw sockets 0.226 sec
		2344	POE/select, optimized 0.404 sec
		2345
		2346	AnyEvent/select/nb 0.085 sec
		2347	AnyEvent/EV/nb 0.068 sec
		2348	+state machine 0.134 sec
		2349
		2350	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2351	benchmarks actually make blocking connects and use 100% blocking I/O,
		2352	defeating the purpose of an event-based solution. All of the newly
		2353	written AnyEvent benchmarks use 100% non-blocking connects (using
		2354	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2355	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2356	generally require a lot more bookkeeping and event handling than blocking
		2357	connects (which involve a single syscall only).
		2358
		2359	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2360	offers similar expressive power as POE and IO::Lambda, using conventional
		2361	Perl syntax. This means that both the echo server and the client are 100%
		2362	non-blocking, further placing it at a disadvantage.
		2363
		2364	As you can see, the AnyEvent + EV combination even beats the
		2365	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2366	backend easily beats IO::Lambda and POE.
		2367
		2368	And even the 100% non-blocking version written using the high-level (and
		2369	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2370	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2371	in a non-blocking way.
		2372
		2373	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2374	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2375	part of the IO::lambda distribution and were used without any changes.
		2376
1892		2377
1893	=head1 SIGNALS	2378	=head1 SIGNALS
1894		2379
1895	AnyEvent currently installs handlers for these signals:	2380	AnyEvent currently installs handlers for these signals:
1896		2381
…		…
1899	=item SIGCHLD	2384	=item SIGCHLD
1900		2385
1901	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2386	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	2387	emulation for event loops that do not support them natively. Also, some
1903	event loops install a similar handler.	2388	event loops install a similar handler.
		2389
		2390	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2391	AnyEvent will reset it to default, to avoid losing child exit statuses.
1904		2392
1905	=item SIGPIPE	2393	=item SIGPIPE
1906		2394
1907	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2395	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1908	when AnyEvent gets loaded.	2396	when AnyEvent gets loaded.
…		…
1920		2408
1921	=back	2409	=back
1922		2410
1923	=cut	2411	=cut
1924		2412
		2413	undef $SIG{CHLD}
		2414	if $SIG{CHLD} eq 'IGNORE';
		2415
1925	$SIG{PIPE} = sub { }	2416	$SIG{PIPE} = sub { }
1926	unless defined $SIG{PIPE};	2417	unless defined $SIG{PIPE};
		2418
		2419	=head1 RECOMMENDED/OPTIONAL MODULES
		2420
		2421	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2422	it's built-in modules) are required to use it.
		2423
		2424	That does not mean that AnyEvent won't take advantage of some additional
		2425	modules if they are installed.
		2426
		2427	This section epxlains which additional modules will be used, and how they
		2428	affect AnyEvent's operetion.
		2429
		2430	=over 4
		2431
		2432	=item L<Async::Interrupt>
		2433
		2434	This slightly arcane module is used to implement fast signal handling: To
		2435	my knowledge, there is no way to do completely race-free and quick
		2436	signal handling in pure perl. To ensure that signals still get
		2437	delivered, AnyEvent will start an interval timer to wake up perl (and
		2438	catch the signals) with some delay (default is 10 seconds, look for
		2439	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2440
		2441	If this module is available, then it will be used to implement signal
		2442	catching, which means that signals will not be delayed, and the event loop
		2443	will not be interrupted regularly, which is more efficient (And good for
		2444	battery life on laptops).
		2445
		2446	This affects not just the pure-perl event loop, but also other event loops
		2447	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2448
		2449	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2450	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2451	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2452	does nothing for those backends.
		2453
		2454	=item L<EV>
		2455
		2456	This module isn't really "optional", as it is simply one of the backend
		2457	event loops that AnyEvent can use. However, it is simply the best event
		2458	loop available in terms of features, speed and stability: It supports
		2459	the AnyEvent API optimally, implements all the watcher types in XS, does
		2460	automatic timer adjustments even when no monotonic clock is available,
		2461	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2462	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2463	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2464
		2465	=item L<Guard>
		2466
		2467	The guard module, when used, will be used to implement
		2468	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2469	lot less memory), but otherwise doesn't affect guard operation much. It is
		2470	purely used for performance.
		2471
		2472	=item L<JSON> and L<JSON::XS>
		2473
		2474	This module is required when you want to read or write JSON data via
		2475	L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2476	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2477
		2478	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2479	installed.
		2480
		2481	=item L<Net::SSLeay>
		2482
		2483	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2484	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2485	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2486
		2487	=item L<Time::HiRes>
		2488
		2489	This module is part of perl since release 5.008. It will be used when the
		2490	chosen event library does not come with a timing source on it's own. The
		2491	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2492	try to use a monotonic clock for timing stability.
		2493
		2494	=back
1927		2495
1928		2496
1929	=head1 FORK	2497	=head1 FORK
1930		2498
1931	Most event libraries are not fork-safe. The ones who are usually are	2499	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>	2500	because they rely on inefficient but fork-safe C<select> or C<poll>
1933	calls. Only L<EV> is fully fork-aware.	2501	calls. Only L<EV> is fully fork-aware.
1934		2502
1935	If you have to fork, you must either do so I<before> creating your first	2503	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.	2504	watcher OR you must not use AnyEvent at all in the child OR you must do
		2505	something completely out of the scope of AnyEvent.
1937		2506
1938		2507
1939	=head1 SECURITY CONSIDERATIONS	2508	=head1 SECURITY CONSIDERATIONS
1940		2509
1941	AnyEvent can be forced to load any event model via	2510	AnyEvent can be forced to load any event model via
…		…
1955	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2524	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	2525	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	2526	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1958	$ENV{PERL_ANYEVENT_STRICT}.	2527	$ENV{PERL_ANYEVENT_STRICT}.
1959		2528
		2529	Note that AnyEvent will remove I<all> environment variables starting with
		2530	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2531	enabled.
		2532
1960		2533
1961	=head1 BUGS	2534	=head1 BUGS
1962		2535
1963	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2536	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	2537	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>.	2548	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1976		2549
1977	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2550	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1978	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2551	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1979	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2552	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1980	L<AnyEvent::Impl::POE>.	2553	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1981		2554
1982	Non-blocking file handles, sockets, TCP clients and	2555	Non-blocking file handles, sockets, TCP clients and
1983	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2556	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1984		2557
1985	Asynchronous DNS: L<AnyEvent::DNS>.	2558	Asynchronous DNS: L<AnyEvent::DNS>.
1986		2559
1987	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2560	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2561	L<Coro::Event>,
1988		2562
1989	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2563	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2564	L<AnyEvent::HTTP>.
1990		2565
1991		2566
1992	=head1 AUTHOR	2567	=head1 AUTHOR
1993		2568
1994	Marc Lehmann <schmorp@schmorp.de>	2569	Marc Lehmann <schmorp@schmorp.de>

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