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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> (or a naked 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
…		…
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
…		…
403		452
404	This means you cannot create a child watcher as the very first	453	This means you cannot create a child watcher as the very first
405	thing in an AnyEvent program, you I<have> to create at least one	454	thing in an AnyEvent program, you I<have> to create at least one
406	watcher before you C<fork> the child (alternatively, you can call	455	watcher before you C<fork> the child (alternatively, you can call
407	C<AnyEvent::detect>).	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.
408		461
409	Example: fork a process and wait for it	462	Example: fork a process and wait for it
410		463
411	my $done = AnyEvent->condvar;	464	my $done = AnyEvent->condvar;
412		465
…		…
424	# do something else, then wait for process exit	477	# do something else, then wait for process exit
425	$done->recv;	478	$done->recv;
426		479
427	=head2 IDLE WATCHERS	480	=head2 IDLE WATCHERS
428		481
		482	$w = AnyEvent->idle (cb => <callback>);
		483
429	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
430	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
431	"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
432	attention by the event loop".	487	attention by the event loop".
433		488
…		…
459	});	514	});
460	});	515	});
461		516
462	=head2 CONDITION VARIABLES	517	=head2 CONDITION VARIABLES
463		518
		519	$cv = AnyEvent->condvar;
		520
		521	$cv->send (<list>);
		522	my @res = $cv->recv;
		523
464	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
465	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
466	will actively watch for new events and call your callbacks.	526	will actively watch for new events and call your callbacks.
467		527
468	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
469	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).
470		530
471	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
472	because they represent a condition that must become true.	532	because they represent a condition that must become true.
473		533
		534	Now is probably a good time to look at the examples further below.
		535
474	Condition variables can be created by calling the C<< AnyEvent->condvar	536	Condition variables can be created by calling the C<< AnyEvent->condvar
475	>> method, usually without arguments. The only argument pair allowed is	537	>> method, usually without arguments. The only argument pair allowed is
476
477	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
478	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
479	the results).	540	the results).
480		541
481	After creation, the condition variable is "false" until it becomes "true"	542	After creation, the condition variable is "false" until it becomes "true"
…		…
486	Condition variables are similar to callbacks, except that you can	547	Condition variables are similar to callbacks, except that you can
487	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
488	in time where multiple outstanding events have been processed. And yet	549	in time where multiple outstanding events have been processed. And yet
489	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
490	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
491	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.
492		554
493	Condition variables are very useful to signal that something has finished,	555	Condition variables are very useful to signal that something has finished,
494	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,
495	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
496	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
…		…
530	after => 1,	592	after => 1,
531	cb => sub { $result_ready->send },	593	cb => sub { $result_ready->send },
532	);	594	);
533		595
534	# this "blocks" (while handling events) till the callback	596	# this "blocks" (while handling events) till the callback
535	# calls send	597	# calls -<send
536	$result_ready->recv;	598	$result_ready->recv;
537		599
538	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
539	condition variables are also code references.	601	variables are also callable directly.
540		602
541	my $done = AnyEvent->condvar;	603	my $done = AnyEvent->condvar;
542	my $delay = AnyEvent->timer (after => 5, cb => $done);	604	my $delay = AnyEvent->timer (after => 5, cb => $done);
543	$done->recv;	605	$done->recv;
544		606
…		…
550		612
551	...	613	...
552		614
553	my @info = $couchdb->info->recv;	615	my @info = $couchdb->info->recv;
554		616
555	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
556	results are available:	618	results are available:
557		619
558	$couchdb->info->cb (sub {	620	$couchdb->info->cb (sub {
559	my @info = $_[0]->recv;	621	my @info = $_[0]->recv;
560	});	622	});
…		…
578	immediately from within send.	640	immediately from within send.
579		641
580	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
581	future C<< ->recv >> calls.	643	future C<< ->recv >> calls.
582		644
583	Condition variables are overloaded so one can call them directly	645	Condition variables are overloaded so one can call them directly (as if
584	(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
585	C<send>. Note, however, that many C-based event loops do not handle	647	C<send>.
586	overloading, so as tempting as it may be, passing a condition variable
587	instead of a callback does not work. Both the pure perl and EV loops
588	support overloading, however, as well as all functions that use perl to
589	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
590	example).
591		648
592	=item $cv->croak ($error)	649	=item $cv->croak ($error)
593		650
594	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
595	C<Carp::croak> with the given error message/object/scalar.	652	C<Carp::croak> with the given error message/object/scalar.
596		653
597	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
598	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.
599		660
600	=item $cv->begin ([group callback])	661	=item $cv->begin ([group callback])
601		662
602	=item $cv->end	663	=item $cv->end
603		664
…		…
605	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
606	to use a condition variable for the whole process.	667	to use a condition variable for the whole process.
607		668
608	Every call to C<< ->begin >> will increment a counter, and every call to	669	Every call to C<< ->begin >> will increment a counter, and every call to
609	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
610	>>, the (last) callback passed to C<begin> will be executed. That callback	671	>>, the (last) callback passed to C<begin> will be executed, passing the
611	is I<supposed> to call C<< ->send >>, but that is not required. If no	672	condvar as first argument. That callback is I<supposed> to call C<< ->send
612	callback was set, C<send> will be called without any arguments.	673	>>, but that is not required. If no group callback was set, C<send> will
		674	be called without any arguments.
613		675
614	You can think of C<< $cv->send >> giving you an OR condition (one call	676	You can think of C<< $cv->send >> giving you an OR condition (one call
615	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND	677	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
616	condition (all C<begin> calls must be C<end>'ed before the condvar sends).	678	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
617		679
…		…
644	begung can potentially be zero:	706	begung can potentially be zero:
645		707
646	my $cv = AnyEvent->condvar;	708	my $cv = AnyEvent->condvar;
647		709
648	my %result;	710	my %result;
649	$cv->begin (sub { $cv->send (\%result) });	711	$cv->begin (sub { shift->send (\%result) });
650		712
651	for my $host (@list_of_hosts) {	713	for my $host (@list_of_hosts) {
652	$cv->begin;	714	$cv->begin;
653	ping_host_then_call_callback $host, sub {	715	ping_host_then_call_callback $host, sub {
654	$result{$host} = ...;	716	$result{$host} = ...;
…		…
699	function will call C<croak>.	761	function will call C<croak>.
700		762
701	In list context, all parameters passed to C<send> will be returned,	763	In list context, all parameters passed to C<send> will be returned,
702	in scalar context only the first one will be returned.	764	in scalar context only the first one will be returned.
703		765
		766	Note that doing a blocking wait in a callback is not supported by any
		767	event loop, that is, recursive invocation of a blocking C<< ->recv
		768	>> is not allowed, and the C<recv> call will C<croak> if such a
		769	condition is detected. This condition can be slightly loosened by using
		770	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		771	any thread that doesn't run the event loop itself.
		772
704	Not all event models support a blocking wait - some die in that case	773	Not all event models support a blocking wait - some die in that case
705	(programs might want to do that to stay interactive), so I<if you are	774	(programs might want to do that to stay interactive), so I<if you are
706	using this from a module, never require a blocking wait>, but let the	775	using this from a module, never require a blocking wait>. Instead, let the
707	caller decide whether the call will block or not (for example, by coupling	776	caller decide whether the call will block or not (for example, by coupling
708	condition variables with some kind of request results and supporting	777	condition variables with some kind of request results and supporting
709	callbacks so the caller knows that getting the result will not block,	778	callbacks so the caller knows that getting the result will not block,
710	while still supporting blocking waits if the caller so desires).	779	while still supporting blocking waits if the caller so desires).
711		780
712	Another reason I<never> to C<< ->recv >> in a module is that you cannot
713	sensibly have two C<< ->recv >>'s in parallel, as that would require
714	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
715	can supply.
716
717	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
718	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
719	versions and also integrates coroutines into AnyEvent, making blocking
720	C<< ->recv >> calls perfectly safe as long as they are done from another
721	coroutine (one that doesn't run the event loop).
722
723	You can ensure that C<< -recv >> never blocks by setting a callback and	781	You can ensure that C<< -recv >> never blocks by setting a callback and
724	only calling C<< ->recv >> from within that callback (or at a later	782	only calling C<< ->recv >> from within that callback (or at a later
725	time). This will work even when the event loop does not support blocking	783	time). This will work even when the event loop does not support blocking
726	waits otherwise.	784	waits otherwise.
727		785
…		…
733	=item $cb = $cv->cb ($cb->($cv))	791	=item $cb = $cv->cb ($cb->($cv))
734		792
735	This is a mutator function that returns the callback set and optionally	793	This is a mutator function that returns the callback set and optionally
736	replaces it before doing so.	794	replaces it before doing so.
737		795
738	The callback will be called when the condition becomes "true", i.e. when	796	The callback will be called when the condition becomes (or already was)
739	C<send> or C<croak> are called, with the only argument being the condition	797	"true", i.e. when C<send> or C<croak> are called (or were called), with
740	variable itself. Calling C<recv> inside the callback or at any later time	798	the only argument being the condition variable itself. Calling C<recv>
741	is guaranteed not to block.	799	inside the callback or at any later time is guaranteed not to block.
742		800
743	=back	801	=back
744		802
		803	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		804
		805	The available backend classes are (every class has its own manpage):
		806
		807	=over 4
		808
		809	=item Backends that are autoprobed when no other event loop can be found.
		810
		811	EV is the preferred backend when no other event loop seems to be in
		812	use. If EV is not installed, then AnyEvent will fall back to its own
		813	pure-perl implementation, which is available everywhere as it comes with
		814	AnyEvent itself.
		815
		816	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		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::Event based on Event, very stable, few glitches.
		828	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		829	AnyEvent::Impl::Tk based on Tk, very broken.
		830	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		831	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		832	AnyEvent::Impl::Irssi used when running within irssi.
		833
		834	=item Backends with special needs.
		835
		836	Qt requires the Qt::Application to be instantiated first, but will
		837	otherwise be picked up automatically. As long as the main program
		838	instantiates the application before any AnyEvent watchers are created,
		839	everything should just work.
		840
		841	AnyEvent::Impl::Qt based on Qt.
		842
		843	Support for IO::Async can only be partial, as it is too broken and
		844	architecturally limited to even support the AnyEvent API. It also
		845	is the only event loop that needs the loop to be set explicitly, so
		846	it can only be used by a main program knowing about AnyEvent. See
		847	L<AnyEvent::Impl::Async> for the gory details.
		848
		849	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		850
		851	=item Event loops that are indirectly supported via other backends.
		852
		853	Some event loops can be supported via other modules:
		854
		855	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		856
		857	B<WxWidgets> has no support for watching file handles. However, you can
		858	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		859	polls 20 times per second, which was considered to be too horrible to even
		860	consider for AnyEvent.
		861
		862	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		863	backend, so it can be supported through POE.
		864
		865	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		866	load L<POE> when detecting them, in the hope that POE will pick them up,
		867	in which case everything will be automatic.
		868
		869	=back
		870
745	=head1 GLOBAL VARIABLES AND FUNCTIONS	871	=head1 GLOBAL VARIABLES AND FUNCTIONS
746		872
		873	These are not normally required to use AnyEvent, but can be useful to
		874	write AnyEvent extension modules.
		875
747	=over 4	876	=over 4
748		877
749	=item $AnyEvent::MODEL	878	=item $AnyEvent::MODEL
750		879
751	Contains C<undef> until the first watcher is being created. Then it	880	Contains C<undef> until the first watcher is being created, before the
		881	backend has been autodetected.
		882
752	contains the event model that is being used, which is the name of the	883	Afterwards it contains the event model that is being used, which is the
753	Perl class implementing the model. This class is usually one of the	884	name of the Perl class implementing the model. This class is usually one
754	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	885	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
755	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	886	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
756		887	will be C<urxvt::anyevent>).
757	The known classes so far are:
758
759	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
760	AnyEvent::Impl::Event based on Event, second best choice.
761	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
762	AnyEvent::Impl::Glib based on Glib, third-best choice.
763	AnyEvent::Impl::Tk based on Tk, very bad choice.
764	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
765	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
766	AnyEvent::Impl::POE based on POE, not generic enough for full support.
767
768	# warning, support for IO::Async is only partial, as it is too broken
769	# and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
770	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
771
772	There is no support for WxWidgets, as WxWidgets has no support for
773	watching file handles. However, you can use WxWidgets through the
774	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
775	second, which was considered to be too horrible to even consider for
776	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
777	it's adaptor.
778
779	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
780	autodetecting them.
781		888
782	=item AnyEvent::detect	889	=item AnyEvent::detect
783		890
784	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	891	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
785	if necessary. You should only call this function right before you would	892	if necessary. You should only call this function right before you would
786	have created an AnyEvent watcher anyway, that is, as late as possible at	893	have created an AnyEvent watcher anyway, that is, as late as possible at
787	runtime.	894	runtime, and not e.g. while initialising of your module.
		895
		896	If you need to do some initialisation before AnyEvent watchers are
		897	created, use C<post_detect>.
788		898
789	=item $guard = AnyEvent::post_detect { BLOCK }	899	=item $guard = AnyEvent::post_detect { BLOCK }
790		900
791	Arranges for the code block to be executed as soon as the event model is	901	Arranges for the code block to be executed as soon as the event model is
792	autodetected (or immediately if this has already happened).	902	autodetected (or immediately if this has already happened).
793		903
		904	The block will be executed I<after> the actual backend has been detected
		905	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		906	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		907	other initialisations - see the sources of L<AnyEvent::Strict> or
		908	L<AnyEvent::AIO> to see how this is used.
		909
		910	The most common usage is to create some global watchers, without forcing
		911	event module detection too early, for example, L<AnyEvent::AIO> creates
		912	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		913	avoid autodetecting the event module at load time.
		914
794	If called in scalar or list context, then it creates and returns an object	915	If called in scalar or list context, then it creates and returns an object
795	that automatically removes the callback again when it is destroyed. See	916	that automatically removes the callback again when it is destroyed (or
		917	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
796	L<Coro::BDB> for a case where this is useful.	918	a case where this is useful.
		919
		920	Example: Create a watcher for the IO::AIO module and store it in
		921	C<$WATCHER>. Only do so after the event loop is initialised, though.
		922
		923	our WATCHER;
		924
		925	my $guard = AnyEvent::post_detect {
		926	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		927	};
		928
		929	# the ||= is important in case post_detect immediately runs the block,
		930	# as to not clobber the newly-created watcher. assigning both watcher and
		931	# post_detect guard to the same variable has the advantage of users being
		932	# able to just C<undef $WATCHER> if the watcher causes them grief.
		933
		934	$WATCHER ||= $guard;
797		935
798	=item @AnyEvent::post_detect	936	=item @AnyEvent::post_detect
799		937
800	If there are any code references in this array (you can C<push> to it	938	If there are any code references in this array (you can C<push> to it
801	before or after loading AnyEvent), then they will called directly after	939	before or after loading AnyEvent), then they will called directly after
802	the event loop has been chosen.	940	the event loop has been chosen.
803		941
804	You should check C<$AnyEvent::MODEL> before adding to this array, though:	942	You should check C<$AnyEvent::MODEL> before adding to this array, though:
805	if it contains a true value then the event loop has already been detected,	943	if it is defined then the event loop has already been detected, and the
806	and the array will be ignored.	944	array will be ignored.
807		945
808	Best use C<AnyEvent::post_detect { BLOCK }> instead.	946	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		947	it,as it takes care of these details.
		948
		949	This variable is mainly useful for modules that can do something useful
		950	when AnyEvent is used and thus want to know when it is initialised, but do
		951	not need to even load it by default. This array provides the means to hook
		952	into AnyEvent passively, without loading it.
809		953
810	=back	954	=back
811		955
812	=head1 WHAT TO DO IN A MODULE	956	=head1 WHAT TO DO IN A MODULE
813		957
…		…
868		1012
869		1013
870	=head1 OTHER MODULES	1014	=head1 OTHER MODULES
871		1015
872	The following is a non-exhaustive list of additional modules that use	1016	The following is a non-exhaustive list of additional modules that use
873	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1017	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
874	in the same program. Some of the modules come with AnyEvent, some are	1018	modules and other event loops in the same program. Some of the modules
875	available via CPAN.	1019	come with AnyEvent, most are available via CPAN.
876		1020
877	=over 4	1021	=over 4
878		1022
879	=item L<AnyEvent::Util>	1023	=item L<AnyEvent::Util>
880		1024
…		…
889		1033
890	=item L<AnyEvent::Handle>	1034	=item L<AnyEvent::Handle>
891		1035
892	Provide read and write buffers, manages watchers for reads and writes,	1036	Provide read and write buffers, manages watchers for reads and writes,
893	supports raw and formatted I/O, I/O queued and fully transparent and	1037	supports raw and formatted I/O, I/O queued and fully transparent and
894	non-blocking SSL/TLS.	1038	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
895		1039
896	=item L<AnyEvent::DNS>	1040	=item L<AnyEvent::DNS>
897		1041
898	Provides rich asynchronous DNS resolver capabilities.	1042	Provides rich asynchronous DNS resolver capabilities.
899		1043
…		…
927		1071
928	=item L<AnyEvent::GPSD>	1072	=item L<AnyEvent::GPSD>
929		1073
930	A non-blocking interface to gpsd, a daemon delivering GPS information.	1074	A non-blocking interface to gpsd, a daemon delivering GPS information.
931		1075
		1076	=item L<AnyEvent::IRC>
		1077
		1078	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1079
		1080	=item L<AnyEvent::XMPP>
		1081
		1082	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1083	Net::XMPP2>.
		1084
932	=item L<AnyEvent::IGS>	1085	=item L<AnyEvent::IGS>
933		1086
934	A non-blocking interface to the Internet Go Server protocol (used by	1087	A non-blocking interface to the Internet Go Server protocol (used by
935	L<App::IGS>).	1088	L<App::IGS>).
936		1089
937	=item L<AnyEvent::IRC>
938
939	AnyEvent based IRC client module family (replacing the older Net::IRC3).
940
941	=item L<Net::XMPP2>
942
943	AnyEvent based XMPP (Jabber protocol) module family.
944
945	=item L<Net::FCP>	1090	=item L<Net::FCP>
946		1091
947	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1092	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
948	of AnyEvent.	1093	of AnyEvent.
949		1094
…		…
953		1098
954	=item L<Coro>	1099	=item L<Coro>
955		1100
956	Has special support for AnyEvent via L<Coro::AnyEvent>.	1101	Has special support for AnyEvent via L<Coro::AnyEvent>.
957		1102
958	=item L<IO::Lambda>
959
960	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
961
962	=back	1103	=back
963		1104
964	=cut	1105	=cut
965		1106
966	package AnyEvent;	1107	package AnyEvent;
967		1108
		1109	# basically a tuned-down version of common::sense
		1110	sub common_sense {
968	no warnings;	1111	# no warnings
		1112	${^WARNING_BITS} ^= ${^WARNING_BITS};
969	use strict qw(vars subs);	1113	# use strict vars subs
		1114	$^H |= 0x00000600;
		1115	}
970		1116
		1117	BEGIN { AnyEvent::common_sense }
		1118
971	use Carp;	1119	use Carp ();
972		1120
973	our $VERSION = 4.8;	1121	our $VERSION = '5.1';
974	our $MODEL;	1122	our $MODEL;
975		1123
976	our $AUTOLOAD;	1124	our $AUTOLOAD;
977	our @ISA;	1125	our @ISA;
978		1126
979	our @REGISTRY;	1127	our @REGISTRY;
980		1128
981	our $WIN32;	1129	our $WIN32;
		1130
		1131	our $VERBOSE;
982		1132
983	BEGIN {	1133	BEGIN {
984	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1134	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
985	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1135	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
986		1136
987	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1137	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
988	if ${^TAINT};	1138	if ${^TAINT};
989	}
990		1139
991	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1140	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1141
		1142	}
		1143
		1144	our $MAX_SIGNAL_LATENCY = 10;
992		1145
993	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1146	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
994		1147
995	{	1148	{
996	my $idx;	1149	my $idx;
…		…
998	for reverse split /\s*,\s*/,	1151	for reverse split /\s*,\s*/,
999	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1152	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1000	}	1153	}
1001		1154
1002	my @models = (	1155	my @models = (
1003	[EV:: => AnyEvent::Impl::EV::],	1156	[EV:: => AnyEvent::Impl::EV:: , 1],
1004	[Event:: => AnyEvent::Impl::Event::],
1005	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1157	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1006	# everything below here will not be autoprobed	1158	# everything below here will not (normally) be autoprobed
1007	# as the pureperl backend should work everywhere	1159	# as the pureperl backend should work everywhere
1008	# and is usually faster	1160	# and is usually faster
		1161	[Event:: => AnyEvent::Impl::Event::, 1],
		1162	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1163	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1164	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1009	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1165	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1010	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
1011	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1012	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1166	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1013	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1167	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1014	[Wx:: => AnyEvent::Impl::POE::],	1168	[Wx:: => AnyEvent::Impl::POE::],
1015	[Prima:: => AnyEvent::Impl::POE::],	1169	[Prima:: => AnyEvent::Impl::POE::],
1016	# IO::Async is just too broken - we would need workaorunds for its	1170	# IO::Async is just too broken - we would need workarounds for its
1017	# byzantine signal and broken child handling, among others.	1171	# byzantine signal and broken child handling, among others.
1018	# IO::Async is rather hard to detect, as it doesn't have any	1172	# IO::Async is rather hard to detect, as it doesn't have any
1019	# obvious default class.	1173	# obvious default class.
1020	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program	1174	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1021	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program	1175	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1022	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program	1176	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1177	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1023	);	1178	);
1024		1179
1025	our %method = map +($_ => 1),	1180	our %method = map +($_ => 1),
1026	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1181	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
1027		1182
…		…
1031	my ($cb) = @_;	1186	my ($cb) = @_;
1032		1187
1033	if ($MODEL) {	1188	if ($MODEL) {
1034	$cb->();	1189	$cb->();
1035		1190
1036	1	1191	undef
1037	} else {	1192	} else {
1038	push @post_detect, $cb;	1193	push @post_detect, $cb;
1039		1194
1040	defined wantarray	1195	defined wantarray
1041	? bless \$cb, "AnyEvent::Util::postdetect"	1196	? bless \$cb, "AnyEvent::Util::postdetect"
…		…
1047	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1202	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1048	}	1203	}
1049		1204
1050	sub detect() {	1205	sub detect() {
1051	unless ($MODEL) {	1206	unless ($MODEL) {
1052	no strict 'refs';
1053	local $SIG{__DIE__};	1207	local $SIG{__DIE__};
1054		1208
1055	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1209	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1056	my $model = "AnyEvent::Impl::$1";	1210	my $model = "AnyEvent::Impl::$1";
1057	if (eval "require $model") {	1211	if (eval "require $model") {
1058	$MODEL = $model;	1212	$MODEL = $model;
1059	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1213	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1060	} else {	1214	} else {
1061	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1215	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1062	}	1216	}
1063	}	1217	}
1064		1218
1065	# check for already loaded models	1219	# check for already loaded models
1066	unless ($MODEL) {	1220	unless ($MODEL) {
1067	for (@REGISTRY, @models) {	1221	for (@REGISTRY, @models) {
1068	my ($package, $model) = @$_;	1222	my ($package, $model) = @$_;
1069	if (${"$package\::VERSION"} > 0) {	1223	if (${"$package\::VERSION"} > 0) {
1070	if (eval "require $model") {	1224	if (eval "require $model") {
1071	$MODEL = $model;	1225	$MODEL = $model;
1072	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1226	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1073	last;	1227	last;
1074	}	1228	}
1075	}	1229	}
1076	}	1230	}
1077		1231
1078	unless ($MODEL) {	1232	unless ($MODEL) {
1079	# try to load a model	1233	# try to autoload a model
1080
1081	for (@REGISTRY, @models) {	1234	for (@REGISTRY, @models) {
1082	my ($package, $model) = @$_;	1235	my ($package, $model, $autoload) = @$_;
		1236	if (
		1237	$autoload
1083	if (eval "require $package"	1238	and eval "require $package"
1084	and ${"$package\::VERSION"} > 0	1239	and ${"$package\::VERSION"} > 0
1085	and eval "require $model") {	1240	and eval "require $model"
		1241	) {
1086	$MODEL = $model;	1242	$MODEL = $model;
1087	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1243	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1088	last;	1244	last;
1089	}	1245	}
1090	}	1246	}
1091		1247
1092	$MODEL	1248	$MODEL
…		…
1108		1264
1109	sub AUTOLOAD {	1265	sub AUTOLOAD {
1110	(my $func = $AUTOLOAD) =~ s/.*://;	1266	(my $func = $AUTOLOAD) =~ s/.*://;
1111		1267
1112	$method{$func}	1268	$method{$func}
1113	or croak "$func: not a valid method for AnyEvent objects";	1269	or Carp::croak "$func: not a valid method for AnyEvent objects";
1114		1270
1115	detect unless $MODEL;	1271	detect unless $MODEL;
1116		1272
1117	my $class = shift;	1273	my $class = shift;
1118	$class->$func (@_);	1274	$class->$func (@_);
…		…
1123	# allow only one watcher per fd, so we dup it to get a different one).	1279	# allow only one watcher per fd, so we dup it to get a different one).
1124	sub _dupfh($$;$$) {	1280	sub _dupfh($$;$$) {
1125	my ($poll, $fh, $r, $w) = @_;	1281	my ($poll, $fh, $r, $w) = @_;
1126		1282
1127	# cygwin requires the fh mode to be matching, unix doesn't	1283	# cygwin requires the fh mode to be matching, unix doesn't
1128	my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">");	1284	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1129		1285
1130	open my $fh2, "$mode&", $fh	1286	open my $fh2, $mode, $fh
1131	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";	1287	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1132		1288
1133	# we assume CLOEXEC is already set by perl in all important cases	1289	# we assume CLOEXEC is already set by perl in all important cases
1134		1290
1135	($fh2, $rw)	1291	($fh2, $rw)
1136	}	1292	}
1137		1293
		1294	=head1 SIMPLIFIED AE API
		1295
		1296	Starting with version 5.0, AnyEvent officially supports a second, much
		1297	simpler, API that is designed to reduce the calling, typing and memory
		1298	overhead.
		1299
		1300	See the L<AE> manpage for details.
		1301
		1302	=cut
		1303
		1304	package AE;
		1305
		1306	our $VERSION = $AnyEvent::VERSION;
		1307
		1308	sub io($$$) {
		1309	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1310	}
		1311
		1312	sub timer($$$) {
		1313	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1314	}
		1315
		1316	sub signal($$) {
		1317	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1318	}
		1319
		1320	sub child($$) {
		1321	AnyEvent->child (pid => $_[0], cb => $_[1])
		1322	}
		1323
		1324	sub idle($) {
		1325	AnyEvent->idle (cb => $_[0])
		1326	}
		1327
		1328	sub cv(;&) {
		1329	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1330	}
		1331
		1332	sub now() {
		1333	AnyEvent->now
		1334	}
		1335
		1336	sub now_update() {
		1337	AnyEvent->now_update
		1338	}
		1339
		1340	sub time() {
		1341	AnyEvent->time
		1342	}
		1343
1138	package AnyEvent::Base;	1344	package AnyEvent::Base;
1139		1345
1140	# default implementations for many methods	1346	# default implementations for many methods
1141		1347
1142	BEGIN {	1348	sub _time {
		1349	# probe for availability of Time::HiRes
1143	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1350	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1351	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1144	*_time = \&Time::HiRes::time;	1352	*_time = \&Time::HiRes::time;
1145	# if (eval "use POSIX (); (POSIX::times())...	1353	# if (eval "use POSIX (); (POSIX::times())...
1146	} else {	1354	} else {
		1355	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1147	*_time = sub { time }; # epic fail	1356	*_time = sub { time }; # epic fail
1148	}	1357	}
		1358
		1359	&_time
1149	}	1360	}
1150		1361
1151	sub time { _time }	1362	sub time { _time }
1152	sub now { _time }	1363	sub now { _time }
1153	sub now_update { }	1364	sub now_update { }
…		…
1158	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1369	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1159	}	1370	}
1160		1371
1161	# default implementation for ->signal	1372	# default implementation for ->signal
1162		1373
		1374	our $HAVE_ASYNC_INTERRUPT;
		1375
		1376	sub _have_async_interrupt() {
		1377	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1378	&& eval "use Async::Interrupt 1.0 (); 1")
		1379	unless defined $HAVE_ASYNC_INTERRUPT;
		1380
		1381	$HAVE_ASYNC_INTERRUPT
		1382	}
		1383
1163	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1384	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1385	our (%SIG_ASY, %SIG_ASY_W);
		1386	our ($SIG_COUNT, $SIG_TW);
1164		1387
1165	sub _signal_exec {	1388	sub _signal_exec {
		1389	$HAVE_ASYNC_INTERRUPT
		1390	? $SIGPIPE_R->drain
1166	sysread $SIGPIPE_R, my $dummy, 4;	1391	: sysread $SIGPIPE_R, my $dummy, 9;
1167		1392
1168	while (%SIG_EV) {	1393	while (%SIG_EV) {
1169	for (keys %SIG_EV) {	1394	for (keys %SIG_EV) {
1170	delete $SIG_EV{$_};	1395	delete $SIG_EV{$_};
1171	$_->() for values %{ $SIG_CB{$_} || {} };	1396	$_->() for values %{ $SIG_CB{$_} || {} };
1172	}	1397	}
1173	}	1398	}
1174	}	1399	}
1175		1400
		1401	# install a dummy wakeup watcher to reduce signal catching latency
		1402	sub _sig_add() {
		1403	unless ($SIG_COUNT++) {
		1404	# try to align timer on a full-second boundary, if possible
		1405	my $NOW = AE::now;
		1406
		1407	$SIG_TW = AE::timer
		1408	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1409	$MAX_SIGNAL_LATENCY,
		1410	sub { } # just for the PERL_ASYNC_CHECK
		1411	;
		1412	}
		1413	}
		1414
		1415	sub _sig_del {
		1416	undef $SIG_TW
		1417	unless --$SIG_COUNT;
		1418	}
		1419
		1420	our $_sig_name_init; $_sig_name_init = sub {
		1421	eval q{ # poor man's autoloading
		1422	undef $_sig_name_init;
		1423
		1424	if (_have_async_interrupt) {
		1425	*sig2num = \&Async::Interrupt::sig2num;
		1426	*sig2name = \&Async::Interrupt::sig2name;
		1427	} else {
		1428	require Config;
		1429
		1430	my %signame2num;
		1431	@signame2num{ split ' ', $Config::Config{sig_name} }
		1432	= split ' ', $Config::Config{sig_num};
		1433
		1434	my @signum2name;
		1435	@signum2name[values %signame2num] = keys %signame2num;
		1436
		1437	*sig2num = sub($) {
		1438	$_[0] > 0 ? shift : $signame2num{+shift}
		1439	};
		1440	*sig2name = sub ($) {
		1441	$_[0] > 0 ? $signum2name[+shift] : shift
		1442	};
		1443	}
		1444	};
		1445	die if $@;
		1446	};
		1447
		1448	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1449	sub sig2name($) { &$_sig_name_init; &sig2name }
		1450
1176	sub signal {	1451	sub signal {
1177	my (undef, %arg) = @_;	1452	eval q{ # poor man's autoloading {}
		1453	# probe for availability of Async::Interrupt
		1454	if (_have_async_interrupt) {
		1455	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1178		1456
1179	unless ($SIGPIPE_R) {	1457	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1180	require Fcntl;	1458	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1181		1459
1182	if (AnyEvent::WIN32) {
1183	require AnyEvent::Util;
1184
1185	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1186	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1187	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1188	} else {	1460	} else {
		1461	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1462
		1463	require Fcntl;
		1464
		1465	if (AnyEvent::WIN32) {
		1466	require AnyEvent::Util;
		1467
		1468	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1469	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1470	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1471	} else {
1189	pipe $SIGPIPE_R, $SIGPIPE_W;	1472	pipe $SIGPIPE_R, $SIGPIPE_W;
1190	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1473	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1191	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1474	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1192		1475
1193	# not strictly required, as $^F is normally 2, but let's make sure...	1476	# not strictly required, as $^F is normally 2, but let's make sure...
1194	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1477	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1195	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1478	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1479	}
		1480
		1481	$SIGPIPE_R
		1482	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1483
		1484	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1196	}	1485	}
1197		1486
1198	$SIGPIPE_R	1487	*signal = sub {
1199	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1488	my (undef, %arg) = @_;
1200		1489
1201	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1202	}
1203
1204	my $signal = uc $arg{signal}	1490	my $signal = uc $arg{signal}
1205	or Carp::croak "required option 'signal' is missing";	1491	or Carp::croak "required option 'signal' is missing";
1206		1492
		1493	if ($HAVE_ASYNC_INTERRUPT) {
		1494	# async::interrupt
		1495
		1496	$signal = sig2num $signal;
1207	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1497	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1498
		1499	$SIG_ASY{$signal} ||= new Async::Interrupt
		1500	cb => sub { undef $SIG_EV{$signal} },
		1501	signal => $signal,
		1502	pipe => [$SIGPIPE_R->filenos],
		1503	pipe_autodrain => 0,
		1504	;
		1505
		1506	} else {
		1507	# pure perl
		1508
		1509	# AE::Util has been loaded in signal
		1510	$signal = sig2name $signal;
		1511	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1512
1208	$SIG{$signal} ||= sub {	1513	$SIG{$signal} ||= sub {
1209	local $!;	1514	local $!;
1210	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1515	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1211	undef $SIG_EV{$signal};	1516	undef $SIG_EV{$signal};
		1517	};
		1518
		1519	# can't do signal processing without introducing races in pure perl,
		1520	# so limit the signal latency.
		1521	_sig_add;
		1522	}
		1523
		1524	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1525	};
		1526
		1527	*AnyEvent::Base::signal::DESTROY = sub {
		1528	my ($signal, $cb) = @{$_[0]};
		1529
		1530	_sig_del;
		1531
		1532	delete $SIG_CB{$signal}{$cb};
		1533
		1534	$HAVE_ASYNC_INTERRUPT
		1535	? delete $SIG_ASY{$signal}
		1536	: # delete doesn't work with older perls - they then
		1537	# print weird messages, or just unconditionally exit
		1538	# instead of getting the default action.
		1539	undef $SIG{$signal}
		1540	unless keys %{ $SIG_CB{$signal} };
		1541	};
1212	};	1542	};
1213		1543	die if $@;
1214	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1544	&signal
1215	}
1216
1217	sub AnyEvent::Base::signal::DESTROY {
1218	my ($signal, $cb) = @{$_[0]};
1219
1220	delete $SIG_CB{$signal}{$cb};
1221
1222	# delete doesn't work with older perls - they then
1223	# print weird messages, or just unconditionally exit
1224	# instead of getting the default action.
1225	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1226	}	1545	}
1227		1546
1228	# default implementation for ->child	1547	# default implementation for ->child
1229		1548
1230	our %PID_CB;	1549	our %PID_CB;
1231	our $CHLD_W;	1550	our $CHLD_W;
1232	our $CHLD_DELAY_W;	1551	our $CHLD_DELAY_W;
1233	our $WNOHANG;	1552	our $WNOHANG;
1234		1553
		1554	sub _emit_childstatus($$) {
		1555	my (undef, $rpid, $rstatus) = @_;
		1556
		1557	$_->($rpid, $rstatus)
		1558	for values %{ $PID_CB{$rpid} || {} },
		1559	values %{ $PID_CB{0} || {} };
		1560	}
		1561
1235	sub _sigchld {	1562	sub _sigchld {
		1563	my $pid;
		1564
		1565	AnyEvent->_emit_childstatus ($pid, $?)
1236	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1566	while ($pid = waitpid -1, $WNOHANG) > 0;
1237	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),
1238	(values %{ $PID_CB{0} || {} });
1239	}
1240	}	1567	}
1241		1568
1242	sub child {	1569	sub child {
1243	my (undef, %arg) = @_;	1570	my (undef, %arg) = @_;
1244		1571
1245	defined (my $pid = $arg{pid} + 0)	1572	defined (my $pid = $arg{pid} + 0)
1246	or Carp::croak "required option 'pid' is missing";	1573	or Carp::croak "required option 'pid' is missing";
1247		1574
1248	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1575	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1249		1576
		1577	# WNOHANG is almost cetrainly 1 everywhere
		1578	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1579	? 1
1250	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1580	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1251		1581
1252	unless ($CHLD_W) {	1582	unless ($CHLD_W) {
1253	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1583	$CHLD_W = AE::signal CHLD => \&_sigchld;
1254	# child could be a zombie already, so make at least one round	1584	# child could be a zombie already, so make at least one round
1255	&_sigchld;	1585	&_sigchld;
1256	}	1586	}
1257		1587
1258	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1588	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
…		…
1284	# never use more then 50% of the time for the idle watcher,	1614	# never use more then 50% of the time for the idle watcher,
1285	# within some limits	1615	# within some limits
1286	$w = 0.0001 if $w < 0.0001;	1616	$w = 0.0001 if $w < 0.0001;
1287	$w = 5 if $w > 5;	1617	$w = 5 if $w > 5;
1288		1618
1289	$w = AnyEvent->timer (after => $w, cb => $rcb);	1619	$w = AE::timer $w, 0, $rcb;
1290	} else {	1620	} else {
1291	# clean up...	1621	# clean up...
1292	undef $w;	1622	undef $w;
1293	undef $rcb;	1623	undef $rcb;
1294	}	1624	}
1295	};	1625	};
1296		1626
1297	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1627	$w = AE::timer 0.05, 0, $rcb;
1298		1628
1299	bless \\$cb, "AnyEvent::Base::idle"	1629	bless \\$cb, "AnyEvent::Base::idle"
1300	}	1630	}
1301		1631
1302	sub AnyEvent::Base::idle::DESTROY {	1632	sub AnyEvent::Base::idle::DESTROY {
…		…
1307		1637
1308	our @ISA = AnyEvent::CondVar::Base::;	1638	our @ISA = AnyEvent::CondVar::Base::;
1309		1639
1310	package AnyEvent::CondVar::Base;	1640	package AnyEvent::CondVar::Base;
1311		1641
1312	use overload	1642	#use overload
1313	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1643	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1314	fallback => 1;	1644	# fallback => 1;
		1645
		1646	# save 300+ kilobytes by dirtily hardcoding overloading
		1647	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1648	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1649	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1650	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1651
		1652	our $WAITING;
1315		1653
1316	sub _send {	1654	sub _send {
1317	# nop	1655	# nop
1318	}	1656	}
1319		1657
…		…
1332	sub ready {	1670	sub ready {
1333	$_[0]{_ae_sent}	1671	$_[0]{_ae_sent}
1334	}	1672	}
1335		1673
1336	sub _wait {	1674	sub _wait {
		1675	$WAITING
		1676	and !$_[0]{_ae_sent}
		1677	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1678
		1679	local $WAITING = 1;
1337	AnyEvent->one_event while !$_[0]{_ae_sent};	1680	AnyEvent->one_event while !$_[0]{_ae_sent};
1338	}	1681	}
1339		1682
1340	sub recv {	1683	sub recv {
1341	$_[0]->_wait;	1684	$_[0]->_wait;
…		…
1343	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1686	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1344	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1687	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1345	}	1688	}
1346		1689
1347	sub cb {	1690	sub cb {
1348	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1691	my $cv = shift;
		1692
		1693	@_
		1694	and $cv->{_ae_cb} = shift
		1695	and $cv->{_ae_sent}
		1696	and (delete $cv->{_ae_cb})->($cv);
		1697
1349	$_[0]{_ae_cb}	1698	$cv->{_ae_cb}
1350	}	1699	}
1351		1700
1352	sub begin {	1701	sub begin {
1353	++$_[0]{_ae_counter};	1702	++$_[0]{_ae_counter};
1354	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1703	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1403	C<PERL_ANYEVENT_MODEL>.	1752	C<PERL_ANYEVENT_MODEL>.
1404		1753
1405	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1754	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1406	model it chooses.	1755	model it chooses.
1407		1756
		1757	When set to C<8> or higher, then AnyEvent will report extra information on
		1758	which optional modules it loads and how it implements certain features.
		1759
1408	=item C<PERL_ANYEVENT_STRICT>	1760	=item C<PERL_ANYEVENT_STRICT>
1409		1761
1410	AnyEvent does not do much argument checking by default, as thorough	1762	AnyEvent does not do much argument checking by default, as thorough
1411	argument checking is very costly. Setting this variable to a true value	1763	argument checking is very costly. Setting this variable to a true value
1412	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1764	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1413	check the arguments passed to most method calls. If it finds any problems,	1765	check the arguments passed to most method calls. If it finds any problems,
1414	it will croak.	1766	it will croak.
1415		1767
1416	In other words, enables "strict" mode.	1768	In other words, enables "strict" mode.
1417		1769
1418	Unlike C<use strict>, it is definitely recommended to keep it off in	1770	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1419	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1771	>>, it is definitely recommended to keep it off in production. Keeping
1420	developing programs can be very useful, however.	1772	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1773	can be very useful, however.
1421		1774
1422	=item C<PERL_ANYEVENT_MODEL>	1775	=item C<PERL_ANYEVENT_MODEL>
1423		1776
1424	This can be used to specify the event model to be used by AnyEvent, before	1777	This can be used to specify the event model to be used by AnyEvent, before
1425	auto detection and -probing kicks in. It must be a string consisting	1778	auto detection and -probing kicks in. It must be a string consisting
…		…
1487		1840
1488	When neither C<ca_file> nor C<ca_path> was specified during	1841	When neither C<ca_file> nor C<ca_path> was specified during
1489	L<AnyEvent::TLS> context creation, and either of these environment	1842	L<AnyEvent::TLS> context creation, and either of these environment
1490	variables exist, they will be used to specify CA certificate locations	1843	variables exist, they will be used to specify CA certificate locations
1491	instead of a system-dependent default.	1844	instead of a system-dependent default.
		1845
		1846	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1847
		1848	When these are set to C<1>, then the respective modules are not
		1849	loaded. Mostly good for testing AnyEvent itself.
1492		1850
1493	=back	1851	=back
1494		1852
1495	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1853	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1496		1854
…		…
1704	through AnyEvent. The benchmark creates a lot of timers (with a zero	2062	through AnyEvent. The benchmark creates a lot of timers (with a zero
1705	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2063	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1706	which it is), lets them fire exactly once and destroys them again.	2064	which it is), lets them fire exactly once and destroys them again.
1707		2065
1708	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2066	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1709	distribution.	2067	distribution. It uses the L<AE> interface, which makes a real difference
		2068	for the EV and Perl backends only.
1710		2069
1711	=head3 Explanation of the columns	2070	=head3 Explanation of the columns
1712		2071
1713	I<watcher> is the number of event watchers created/destroyed. Since	2072	I<watcher> is the number of event watchers created/destroyed. Since
1714	different event models feature vastly different performances, each event	2073	different event models feature vastly different performances, each event
…		…
1735	watcher.	2094	watcher.
1736		2095
1737	=head3 Results	2096	=head3 Results
1738		2097
1739	name watchers bytes create invoke destroy comment	2098	name watchers bytes create invoke destroy comment
1740	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2099	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1741	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2100	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1742	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2101	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1743	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2102	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1744	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2103	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1745	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2104	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1746	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2105	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1747	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2106	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1748	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2107	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1749	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2108	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1750	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2109	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1751	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2110	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1752		2111
1753	=head3 Discussion	2112	=head3 Discussion
1754		2113
1755	The benchmark does I<not> measure scalability of the event loop very	2114	The benchmark does I<not> measure scalability of the event loop very
1756	well. For example, a select-based event loop (such as the pure perl one)	2115	well. For example, a select-based event loop (such as the pure perl one)
…		…
1768	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2127	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1769	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2128	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1770	cycles with POE.	2129	cycles with POE.
1771		2130
1772	C<EV> is the sole leader regarding speed and memory use, which are both	2131	C<EV> is the sole leader regarding speed and memory use, which are both
1773	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2132	maximal/minimal, respectively. When using the L<AE> API there is zero
		2133	overhead (when going through the AnyEvent API create is about 5-6 times
		2134	slower, with other times being equal, so still uses far less memory than
1774	far less memory than any other event loop and is still faster than Event	2135	any other event loop and is still faster than Event natively).
1775	natively.
1776		2136
1777	The pure perl implementation is hit in a few sweet spots (both the	2137	The pure perl implementation is hit in a few sweet spots (both the
1778	constant timeout and the use of a single fd hit optimisations in the perl	2138	constant timeout and the use of a single fd hit optimisations in the perl
1779	interpreter and the backend itself). Nevertheless this shows that it	2139	interpreter and the backend itself). Nevertheless this shows that it
1780	adds very little overhead in itself. Like any select-based backend its	2140	adds very little overhead in itself. Like any select-based backend its
…		…
1854	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2214	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1855	(1%) are active. This mirrors the activity of large servers with many	2215	(1%) are active. This mirrors the activity of large servers with many
1856	connections, most of which are idle at any one point in time.	2216	connections, most of which are idle at any one point in time.
1857		2217
1858	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2218	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1859	distribution.	2219	distribution. It uses the L<AE> interface, which makes a real difference
		2220	for the EV and Perl backends only.
1860		2221
1861	=head3 Explanation of the columns	2222	=head3 Explanation of the columns
1862		2223
1863	I<sockets> is the number of sockets, and twice the number of "servers" (as	2224	I<sockets> is the number of sockets, and twice the number of "servers" (as
1864	each server has a read and write socket end).	2225	each server has a read and write socket end).
…		…
1872	a new one that moves the timeout into the future.	2233	a new one that moves the timeout into the future.
1873		2234
1874	=head3 Results	2235	=head3 Results
1875		2236
1876	name sockets create request	2237	name sockets create request
1877	EV 20000 69.01 11.16	2238	EV 20000 62.66 7.99
1878	Perl 20000 73.32 35.87	2239	Perl 20000 68.32 32.64
1879	IOAsync 20000 157.00 98.14 epoll	2240	IOAsync 20000 174.06 101.15 epoll
1880	IOAsync 20000 159.31 616.06 poll	2241	IOAsync 20000 174.67 610.84 poll
1881	Event 20000 212.62 257.32	2242	Event 20000 202.69 242.91
1882	Glib 20000 651.16 1896.30	2243	Glib 20000 557.01 1689.52
1883	POE 20000 349.67 12317.24 uses POE::Loop::Event	2244	POE 20000 341.54 12086.32 uses POE::Loop::Event
1884		2245
1885	=head3 Discussion	2246	=head3 Discussion
1886		2247
1887	This benchmark I<does> measure scalability and overall performance of the	2248	This benchmark I<does> measure scalability and overall performance of the
1888	particular event loop.	2249	particular event loop.
…		…
2035		2396
2036	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2397	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
2037	emulation for event loops that do not support them natively. Also, some	2398	emulation for event loops that do not support them natively. Also, some
2038	event loops install a similar handler.	2399	event loops install a similar handler.
2039		2400
2040	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will	2401	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2041	reset it to default, to avoid losing child exit statuses.	2402	AnyEvent will reset it to default, to avoid losing child exit statuses.
2042		2403
2043	=item SIGPIPE	2404	=item SIGPIPE
2044		2405
2045	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2406	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
2046	when AnyEvent gets loaded.	2407	when AnyEvent gets loaded.
…		…
2064	if $SIG{CHLD} eq 'IGNORE';	2425	if $SIG{CHLD} eq 'IGNORE';
2065		2426
2066	$SIG{PIPE} = sub { }	2427	$SIG{PIPE} = sub { }
2067	unless defined $SIG{PIPE};	2428	unless defined $SIG{PIPE};
2068		2429
		2430	=head1 RECOMMENDED/OPTIONAL MODULES
		2431
		2432	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2433	it's built-in modules) are required to use it.
		2434
		2435	That does not mean that AnyEvent won't take advantage of some additional
		2436	modules if they are installed.
		2437
		2438	This section epxlains which additional modules will be used, and how they
		2439	affect AnyEvent's operetion.
		2440
		2441	=over 4
		2442
		2443	=item L<Async::Interrupt>
		2444
		2445	This slightly arcane module is used to implement fast signal handling: To
		2446	my knowledge, there is no way to do completely race-free and quick
		2447	signal handling in pure perl. To ensure that signals still get
		2448	delivered, AnyEvent will start an interval timer to wake up perl (and
		2449	catch the signals) with some delay (default is 10 seconds, look for
		2450	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2451
		2452	If this module is available, then it will be used to implement signal
		2453	catching, which means that signals will not be delayed, and the event loop
		2454	will not be interrupted regularly, which is more efficient (And good for
		2455	battery life on laptops).
		2456
		2457	This affects not just the pure-perl event loop, but also other event loops
		2458	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2459
		2460	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2461	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2462	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2463	does nothing for those backends.
		2464
		2465	=item L<EV>
		2466
		2467	This module isn't really "optional", as it is simply one of the backend
		2468	event loops that AnyEvent can use. However, it is simply the best event
		2469	loop available in terms of features, speed and stability: It supports
		2470	the AnyEvent API optimally, implements all the watcher types in XS, does
		2471	automatic timer adjustments even when no monotonic clock is available,
		2472	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2473	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2474	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2475
		2476	=item L<Guard>
		2477
		2478	The guard module, when used, will be used to implement
		2479	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2480	lot less memory), but otherwise doesn't affect guard operation much. It is
		2481	purely used for performance.
		2482
		2483	=item L<JSON> and L<JSON::XS>
		2484
		2485	This module is required when you want to read or write JSON data via
		2486	L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2487	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2488
		2489	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2490	installed.
		2491
		2492	=item L<Net::SSLeay>
		2493
		2494	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2495	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2496	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2497
		2498	=item L<Time::HiRes>
		2499
		2500	This module is part of perl since release 5.008. It will be used when the
		2501	chosen event library does not come with a timing source on it's own. The
		2502	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2503	try to use a monotonic clock for timing stability.
		2504
		2505	=back
		2506
		2507
2069	=head1 FORK	2508	=head1 FORK
2070		2509
2071	Most event libraries are not fork-safe. The ones who are usually are	2510	Most event libraries are not fork-safe. The ones who are usually are
2072	because they rely on inefficient but fork-safe C<select> or C<poll>	2511	because they rely on inefficient but fork-safe C<select> or C<poll>
2073	calls. Only L<EV> is fully fork-aware.	2512	calls. Only L<EV> is fully fork-aware.
2074		2513
2075	If you have to fork, you must either do so I<before> creating your first	2514	If you have to fork, you must either do so I<before> creating your first
2076	watcher OR you must not use AnyEvent at all in the child.	2515	watcher OR you must not use AnyEvent at all in the child OR you must do
		2516	something completely out of the scope of AnyEvent.
2077		2517
2078		2518
2079	=head1 SECURITY CONSIDERATIONS	2519	=head1 SECURITY CONSIDERATIONS
2080		2520
2081	AnyEvent can be forced to load any event model via	2521	AnyEvent can be forced to load any event model via
…		…
2119	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2559	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2120		2560
2121	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2561	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2122	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2562	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2123	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2563	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2124	L<AnyEvent::Impl::POE>.	2564	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2125		2565
2126	Non-blocking file handles, sockets, TCP clients and	2566	Non-blocking file handles, sockets, TCP clients and
2127	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2567	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2128		2568
2129	Asynchronous DNS: L<AnyEvent::DNS>.	2569	Asynchronous DNS: L<AnyEvent::DNS>.
2130		2570
2131	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2571	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2572	L<Coro::Event>,
2132		2573
2133	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2574	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2575	L<AnyEvent::HTTP>.
2134		2576
2135		2577
2136	=head1 AUTHOR	2578	=head1 AUTHOR
2137		2579
2138	Marc Lehmann <schmorp@schmorp.de>	2580	Marc Lehmann <schmorp@schmorp.de>

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