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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.208 by root, Sun Apr 26 18:12:53 2009 UTC vs.
Revision 1.241 by root, Fri Jul 17 18:08:35 2009 UTC

…		…
1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - provide framework for multiple event loops
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported
		6	event loops.
6		7
7	=head1 SYNOPSIS	8	=head1 SYNOPSIS
8		9
9	use AnyEvent;	10	use AnyEvent;
10		11
175	=head2 I/O WATCHERS	176	=head2 I/O WATCHERS
176		177
177	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
178	with the following mandatory key-value pairs as arguments:	179	with the following mandatory key-value pairs as arguments:
179		180
180	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch	181	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
181	for events (AnyEvent might or might not keep a reference to this file	182	for events (AnyEvent might or might not keep a reference to this file
182	handle). Note that only file handles pointing to things for which	183	handle). Note that only file handles pointing to things for which
183	non-blocking operation makes sense are allowed. This includes sockets,	184	non-blocking operation makes sense are allowed. This includes sockets,
184	most character devices, pipes, fifos and so on, but not for example files	185	most character devices, pipes, fifos and so on, but not for example files
185	or block devices.	186	or block devices.
…		…
391		392
392	There is a slight catch to child watchers, however: you usually start them	393	There is a slight catch to child watchers, however: you usually start them
393	I<after> the child process was created, and this means the process could	394	I<after> the child process was created, and this means the process could
394	have exited already (and no SIGCHLD will be sent anymore).	395	have exited already (and no SIGCHLD will be sent anymore).
395		396
396	Not all event models handle this correctly (POE doesn't), but even for	397	Not all event models handle this correctly (neither POE nor IO::Async do,
		398	see their AnyEvent::Impl manpages for details), but even for event models
397	event models that I<do> handle this correctly, they usually need to be	399	that I<do> handle this correctly, they usually need to be loaded before
398	loaded before the process exits (i.e. before you fork in the first place).	400	the process exits (i.e. before you fork in the first place). AnyEvent's
		401	pure perl event loop handles all cases correctly regardless of when you
		402	start the watcher.
399		403
400	This means you cannot create a child watcher as the very first thing in an	404	This means you cannot create a child watcher as the very first
401	AnyEvent program, you I<have> to create at least one watcher before you	405	thing in an AnyEvent program, you I<have> to create at least one
402	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	406	watcher before you C<fork> the child (alternatively, you can call
		407	C<AnyEvent::detect>).
403		408
404	Example: fork a process and wait for it	409	Example: fork a process and wait for it
405		410
406	my $done = AnyEvent->condvar;	411	my $done = AnyEvent->condvar;
407		412
…		…
458		463
459	If you are familiar with some event loops you will know that all of them	464	If you are familiar with some event loops you will know that all of them
460	require you to run some blocking "loop", "run" or similar function that	465	require you to run some blocking "loop", "run" or similar function that
461	will actively watch for new events and call your callbacks.	466	will actively watch for new events and call your callbacks.
462		467
463	AnyEvent is different, it expects somebody else to run the event loop and	468	AnyEvent is slightly different: it expects somebody else to run the event
464	will only block when necessary (usually when told by the user).	469	loop and will only block when necessary (usually when told by the user).
465		470
466	The instrument to do that is called a "condition variable", so called	471	The instrument to do that is called a "condition variable", so called
467	because they represent a condition that must become true.	472	because they represent a condition that must become true.
468		473
		474	Now is probably a good time to look at the examples further below.
		475
469	Condition variables can be created by calling the C<< AnyEvent->condvar	476	Condition variables can be created by calling the C<< AnyEvent->condvar
470	>> method, usually without arguments. The only argument pair allowed is	477	>> method, usually without arguments. The only argument pair allowed is
471
472	C<cb>, which specifies a callback to be called when the condition variable	478	C<cb>, which specifies a callback to be called when the condition variable
473	becomes true, with the condition variable as the first argument (but not	479	becomes true, with the condition variable as the first argument (but not
474	the results).	480	the results).
475		481
476	After creation, the condition variable is "false" until it becomes "true"	482	After creation, the condition variable is "false" until it becomes "true"
…		…
525	after => 1,	531	after => 1,
526	cb => sub { $result_ready->send },	532	cb => sub { $result_ready->send },
527	);	533	);
528		534
529	# this "blocks" (while handling events) till the callback	535	# this "blocks" (while handling events) till the callback
530	# calls send	536	# calls -<send
531	$result_ready->recv;	537	$result_ready->recv;
532		538
533	Example: wait for a timer, but take advantage of the fact that	539	Example: wait for a timer, but take advantage of the fact that condition
534	condition variables are also code references.	540	variables are also callable directly.
535		541
536	my $done = AnyEvent->condvar;	542	my $done = AnyEvent->condvar;
537	my $delay = AnyEvent->timer (after => 5, cb => $done);	543	my $delay = AnyEvent->timer (after => 5, cb => $done);
538	$done->recv;	544	$done->recv;
539		545
…		…
545		551
546	...	552	...
547		553
548	my @info = $couchdb->info->recv;	554	my @info = $couchdb->info->recv;
549		555
550	And this is how you would just ste a callback to be called whenever the	556	And this is how you would just set a callback to be called whenever the
551	results are available:	557	results are available:
552		558
553	$couchdb->info->cb (sub {	559	$couchdb->info->cb (sub {
554	my @info = $_[0]->recv;	560	my @info = $_[0]->recv;
555	});	561	});
…		…
573	immediately from within send.	579	immediately from within send.
574		580
575	Any arguments passed to the C<send> call will be returned by all	581	Any arguments passed to the C<send> call will be returned by all
576	future C<< ->recv >> calls.	582	future C<< ->recv >> calls.
577		583
578	Condition variables are overloaded so one can call them directly	584	Condition variables are overloaded so one can call them directly (as if
579	(as a code reference). Calling them directly is the same as calling	585	they were a code reference). Calling them directly is the same as calling
580	C<send>. Note, however, that many C-based event loops do not handle	586	C<send>.
581	overloading, so as tempting as it may be, passing a condition variable
582	instead of a callback does not work. Both the pure perl and EV loops
583	support overloading, however, as well as all functions that use perl to
584	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
585	example).
586		587
587	=item $cv->croak ($error)	588	=item $cv->croak ($error)
588		589
589	Similar to send, but causes all call's to C<< ->recv >> to invoke	590	Similar to send, but causes all call's to C<< ->recv >> to invoke
590	C<Carp::croak> with the given error message/object/scalar.	591	C<Carp::croak> with the given error message/object/scalar.
591		592
592	This can be used to signal any errors to the condition variable	593	This can be used to signal any errors to the condition variable
593	user/consumer.	594	user/consumer. Doing it this way instead of calling C<croak> directly
		595	delays the error detetcion, but has the overwhelmign advantage that it
		596	diagnoses the error at the place where the result is expected, and not
		597	deep in some event clalback without connection to the actual code causing
		598	the problem.
594		599
595	=item $cv->begin ([group callback])	600	=item $cv->begin ([group callback])
596		601
597	=item $cv->end	602	=item $cv->end
598
599	These two methods are EXPERIMENTAL and MIGHT CHANGE.
600		603
601	These two methods can be used to combine many transactions/events into	604	These two methods can be used to combine many transactions/events into
602	one. For example, a function that pings many hosts in parallel might want	605	one. For example, a function that pings many hosts in parallel might want
603	to use a condition variable for the whole process.	606	to use a condition variable for the whole process.
604		607
…		…
606	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	609	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
607	>>, the (last) callback passed to C<begin> will be executed. That callback	610	>>, the (last) callback passed to C<begin> will be executed. That callback
608	is I<supposed> to call C<< ->send >>, but that is not required. If no	611	is I<supposed> to call C<< ->send >>, but that is not required. If no
609	callback was set, C<send> will be called without any arguments.	612	callback was set, C<send> will be called without any arguments.
610		613
611	Let's clarify this with the ping example:	614	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
		616	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		617
		618	Let's start with a simple example: you have two I/O watchers (for example,
		619	STDOUT and STDERR for a program), and you want to wait for both streams to
		620	close before activating a condvar:
		621
		622	my $cv = AnyEvent->condvar;
		623
		624	$cv->begin; # first watcher
		625	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		626	defined sysread $fh1, my $buf, 4096
		627	or $cv->end;
		628	});
		629
		630	$cv->begin; # second watcher
		631	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		632	defined sysread $fh2, my $buf, 4096
		633	or $cv->end;
		634	});
		635
		636	$cv->recv;
		637
		638	This works because for every event source (EOF on file handle), there is
		639	one call to C<begin>, so the condvar waits for all calls to C<end> before
		640	sending.
		641
		642	The ping example mentioned above is slightly more complicated, as the
		643	there are results to be passwd back, and the number of tasks that are
		644	begung can potentially be zero:
612		645
613	my $cv = AnyEvent->condvar;	646	my $cv = AnyEvent->condvar;
614		647
615	my %result;	648	my %result;
616	$cv->begin (sub { $cv->send (\%result) });	649	$cv->begin (sub { $cv->send (\%result) });
…		…
636	loop, which serves two important purposes: first, it sets the callback	669	loop, which serves two important purposes: first, it sets the callback
637	to be called once the counter reaches C<0>, and second, it ensures that	670	to be called once the counter reaches C<0>, and second, it ensures that
638	C<send> is called even when C<no> hosts are being pinged (the loop	671	C<send> is called even when C<no> hosts are being pinged (the loop
639	doesn't execute once).	672	doesn't execute once).
640		673
641	This is the general pattern when you "fan out" into multiple subrequests:	674	This is the general pattern when you "fan out" into multiple (but
642	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	675	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
643	is called at least once, and then, for each subrequest you start, call	676	the callback and ensure C<end> is called at least once, and then, for each
644	C<begin> and for each subrequest you finish, call C<end>.	677	subrequest you start, call C<begin> and for each subrequest you finish,
		678	call C<end>.
645		679
646	=back	680	=back
647		681
648	=head3 METHODS FOR CONSUMERS	682	=head3 METHODS FOR CONSUMERS
649		683
…		…
665	function will call C<croak>.	699	function will call C<croak>.
666		700
667	In list context, all parameters passed to C<send> will be returned,	701	In list context, all parameters passed to C<send> will be returned,
668	in scalar context only the first one will be returned.	702	in scalar context only the first one will be returned.
669		703
		704	Note that doing a blocking wait in a callback is not supported by any
		705	event loop, that is, recursive invocation of a blocking C<< ->recv
		706	>> is not allowed, and the C<recv> call will C<croak> if such a
		707	condition is detected. This condition can be slightly loosened by using
		708	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		709	any thread that doesn't run the event loop itself.
		710
670	Not all event models support a blocking wait - some die in that case	711	Not all event models support a blocking wait - some die in that case
671	(programs might want to do that to stay interactive), so I<if you are	712	(programs might want to do that to stay interactive), so I<if you are
672	using this from a module, never require a blocking wait>, but let the	713	using this from a module, never require a blocking wait>. Instead, let the
673	caller decide whether the call will block or not (for example, by coupling	714	caller decide whether the call will block or not (for example, by coupling
674	condition variables with some kind of request results and supporting	715	condition variables with some kind of request results and supporting
675	callbacks so the caller knows that getting the result will not block,	716	callbacks so the caller knows that getting the result will not block,
676	while still supporting blocking waits if the caller so desires).	717	while still supporting blocking waits if the caller so desires).
677		718
678	Another reason I<never> to C<< ->recv >> in a module is that you cannot
679	sensibly have two C<< ->recv >>'s in parallel, as that would require
680	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
681	can supply.
682
683	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
684	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
685	versions and also integrates coroutines into AnyEvent, making blocking
686	C<< ->recv >> calls perfectly safe as long as they are done from another
687	coroutine (one that doesn't run the event loop).
688
689	You can ensure that C<< -recv >> never blocks by setting a callback and	719	You can ensure that C<< -recv >> never blocks by setting a callback and
690	only calling C<< ->recv >> from within that callback (or at a later	720	only calling C<< ->recv >> from within that callback (or at a later
691	time). This will work even when the event loop does not support blocking	721	time). This will work even when the event loop does not support blocking
692	waits otherwise.	722	waits otherwise.
693		723
…		…
706	variable itself. Calling C<recv> inside the callback or at any later time	736	variable itself. Calling C<recv> inside the callback or at any later time
707	is guaranteed not to block.	737	is guaranteed not to block.
708		738
709	=back	739	=back
710		740
		741	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		742
		743	The available backend classes are (every class has its own manpage):
		744
		745	=over 4
		746
		747	=item Backends that are autoprobed when no other event loop can be found.
		748
		749	EV is the preferred backend when no other event loop seems to be in
		750	use. If EV is not installed, then AnyEvent will try Event, and, failing
		751	that, will fall back to its own pure-perl implementation, which is
		752	available everywhere as it comes with AnyEvent itself.
		753
		754	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		755	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		756	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		757
		758	=item Backends that are transparently being picked up when they are used.
		759
		760	These will be used when they are currently loaded when the first watcher
		761	is created, in which case it is assumed that the application is using
		762	them. This means that AnyEvent will automatically pick the right backend
		763	when the main program loads an event module before anything starts to
		764	create watchers. Nothing special needs to be done by the main program.
		765
		766	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		767	AnyEvent::Impl::Tk based on Tk, very broken.
		768	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		769	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		770
		771	=item Backends with special needs.
		772
		773	Qt requires the Qt::Application to be instantiated first, but will
		774	otherwise be picked up automatically. As long as the main program
		775	instantiates the application before any AnyEvent watchers are created,
		776	everything should just work.
		777
		778	AnyEvent::Impl::Qt based on Qt.
		779
		780	Support for IO::Async can only be partial, as it is too broken and
		781	architecturally limited to even support the AnyEvent API. It also
		782	is the only event loop that needs the loop to be set explicitly, so
		783	it can only be used by a main program knowing about AnyEvent. See
		784	L<AnyEvent::Impl::Async> for the gory details.
		785
		786	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		787
		788	=item Event loops that are indirectly supported via other backends.
		789
		790	Some event loops can be supported via other modules:
		791
		792	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		793
		794	B<WxWidgets> has no support for watching file handles. However, you can
		795	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		796	polls 20 times per second, which was considered to be too horrible to even
		797	consider for AnyEvent.
		798
		799	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		800	backend, so it can be supported through POE.
		801
		802	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		803	load L<POE> when detecting them, in the hope that POE will pick them up,
		804	in which case everything will be automatic.
		805
		806	=back
		807
711	=head1 GLOBAL VARIABLES AND FUNCTIONS	808	=head1 GLOBAL VARIABLES AND FUNCTIONS
712		809
		810	These are not normally required to use AnyEvent, but can be useful to
		811	write AnyEvent extension modules.
		812
713	=over 4	813	=over 4
714		814
715	=item $AnyEvent::MODEL	815	=item $AnyEvent::MODEL
716		816
717	Contains C<undef> until the first watcher is being created. Then it	817	Contains C<undef> until the first watcher is being created, before the
		818	backend has been autodetected.
		819
718	contains the event model that is being used, which is the name of the	820	Afterwards it contains the event model that is being used, which is the
719	Perl class implementing the model. This class is usually one of the	821	name of the Perl class implementing the model. This class is usually one
720	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	822	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
721	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	823	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
722		824	will be C<urxvt::anyevent>).
723	The known classes so far are:
724
725	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
726	AnyEvent::Impl::Event based on Event, second best choice.
727	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
728	AnyEvent::Impl::Glib based on Glib, third-best choice.
729	AnyEvent::Impl::Tk based on Tk, very bad choice.
730	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
731	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
732	AnyEvent::Impl::POE based on POE, not generic enough for full support.
733
734	There is no support for WxWidgets, as WxWidgets has no support for
735	watching file handles. However, you can use WxWidgets through the
736	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
737	second, which was considered to be too horrible to even consider for
738	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
739	it's adaptor.
740
741	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
742	autodetecting them.
743		825
744	=item AnyEvent::detect	826	=item AnyEvent::detect
745		827
746	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	828	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
747	if necessary. You should only call this function right before you would	829	if necessary. You should only call this function right before you would
748	have created an AnyEvent watcher anyway, that is, as late as possible at	830	have created an AnyEvent watcher anyway, that is, as late as possible at
749	runtime.	831	runtime, and not e.g. while initialising of your module.
		832
		833	If you need to do some initialisation before AnyEvent watchers are
		834	created, use C<post_detect>.
750		835
751	=item $guard = AnyEvent::post_detect { BLOCK }	836	=item $guard = AnyEvent::post_detect { BLOCK }
752		837
753	Arranges for the code block to be executed as soon as the event model is	838	Arranges for the code block to be executed as soon as the event model is
754	autodetected (or immediately if this has already happened).	839	autodetected (or immediately if this has already happened).
		840
		841	The block will be executed I<after> the actual backend has been detected
		842	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		843	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		844	other initialisations - see the sources of L<AnyEvent::Strict> or
		845	L<AnyEvent::AIO> to see how this is used.
		846
		847	The most common usage is to create some global watchers, without forcing
		848	event module detection too early, for example, L<AnyEvent::AIO> creates
		849	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		850	avoid autodetecting the event module at load time.
755		851
756	If called in scalar or list context, then it creates and returns an object	852	If called in scalar or list context, then it creates and returns an object
757	that automatically removes the callback again when it is destroyed. See	853	that automatically removes the callback again when it is destroyed. See
758	L<Coro::BDB> for a case where this is useful.	854	L<Coro::BDB> for a case where this is useful.
759		855
…		…
762	If there are any code references in this array (you can C<push> to it	858	If there are any code references in this array (you can C<push> to it
763	before or after loading AnyEvent), then they will called directly after	859	before or after loading AnyEvent), then they will called directly after
764	the event loop has been chosen.	860	the event loop has been chosen.
765		861
766	You should check C<$AnyEvent::MODEL> before adding to this array, though:	862	You should check C<$AnyEvent::MODEL> before adding to this array, though:
767	if it contains a true value then the event loop has already been detected,	863	if it is defined then the event loop has already been detected, and the
768	and the array will be ignored.	864	array will be ignored.
769		865
770	Best use C<AnyEvent::post_detect { BLOCK }> instead.	866	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		867	it,as it takes care of these details.
		868
		869	This variable is mainly useful for modules that can do something useful
		870	when AnyEvent is used and thus want to know when it is initialised, but do
		871	not need to even load it by default. This array provides the means to hook
		872	into AnyEvent passively, without loading it.
771		873
772	=back	874	=back
773		875
774	=head1 WHAT TO DO IN A MODULE	876	=head1 WHAT TO DO IN A MODULE
775		877
…		…
830		932
831		933
832	=head1 OTHER MODULES	934	=head1 OTHER MODULES
833		935
834	The following is a non-exhaustive list of additional modules that use	936	The following is a non-exhaustive list of additional modules that use
835	AnyEvent and can therefore be mixed easily with other AnyEvent modules	937	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
836	in the same program. Some of the modules come with AnyEvent, some are	938	modules and other event loops in the same program. Some of the modules
837	available via CPAN.	939	come with AnyEvent, most are available via CPAN.
838		940
839	=over 4	941	=over 4
840		942
841	=item L<AnyEvent::Util>	943	=item L<AnyEvent::Util>
842		944
…		…
851		953
852	=item L<AnyEvent::Handle>	954	=item L<AnyEvent::Handle>
853		955
854	Provide read and write buffers, manages watchers for reads and writes,	956	Provide read and write buffers, manages watchers for reads and writes,
855	supports raw and formatted I/O, I/O queued and fully transparent and	957	supports raw and formatted I/O, I/O queued and fully transparent and
856	non-blocking SSL/TLS.	958	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
857		959
858	=item L<AnyEvent::DNS>	960	=item L<AnyEvent::DNS>
859		961
860	Provides rich asynchronous DNS resolver capabilities.	962	Provides rich asynchronous DNS resolver capabilities.
861		963
…		…
889		991
890	=item L<AnyEvent::GPSD>	992	=item L<AnyEvent::GPSD>
891		993
892	A non-blocking interface to gpsd, a daemon delivering GPS information.	994	A non-blocking interface to gpsd, a daemon delivering GPS information.
893		995
		996	=item L<AnyEvent::IRC>
		997
		998	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		999
		1000	=item L<AnyEvent::XMPP>
		1001
		1002	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1003	Net::XMPP2>.
		1004
894	=item L<AnyEvent::IGS>	1005	=item L<AnyEvent::IGS>
895		1006
896	A non-blocking interface to the Internet Go Server protocol (used by	1007	A non-blocking interface to the Internet Go Server protocol (used by
897	L<App::IGS>).	1008	L<App::IGS>).
898		1009
899	=item L<AnyEvent::IRC>
900
901	AnyEvent based IRC client module family (replacing the older Net::IRC3).
902
903	=item L<Net::XMPP2>
904
905	AnyEvent based XMPP (Jabber protocol) module family.
906
907	=item L<Net::FCP>	1010	=item L<Net::FCP>
908		1011
909	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1012	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
910	of AnyEvent.	1013	of AnyEvent.
911		1014
…		…
915		1018
916	=item L<Coro>	1019	=item L<Coro>
917		1020
918	Has special support for AnyEvent via L<Coro::AnyEvent>.	1021	Has special support for AnyEvent via L<Coro::AnyEvent>.
919		1022
920	=item L<IO::Lambda>
921
922	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
923
924	=back	1023	=back
925		1024
926	=cut	1025	=cut
927		1026
928	package AnyEvent;	1027	package AnyEvent;
929		1028
930	no warnings;	1029	no warnings;
931	use strict qw(vars subs);	1030	use strict qw(vars subs);
932		1031
933	use Carp;	1032	use Carp ();
934		1033
935	our $VERSION = 4.4;	1034	our $VERSION = 4.83;
936	our $MODEL;	1035	our $MODEL;
937		1036
938	our $AUTOLOAD;	1037	our $AUTOLOAD;
939	our @ISA;	1038	our @ISA;
940		1039
941	our @REGISTRY;	1040	our @REGISTRY;
942		1041
943	our $WIN32;	1042	our $WIN32;
944		1043
945	BEGIN {	1044	BEGIN {
946	my $win32 = ! ! ($^O =~ /mswin32/i);	1045	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
947	eval "sub WIN32(){ $win32 }";	1046	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
		1047
		1048	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1049	if ${^TAINT};
948	}	1050	}
949		1051
950	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1052	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
951		1053
952	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred	1054	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
…		…
963	[Event:: => AnyEvent::Impl::Event::],	1065	[Event:: => AnyEvent::Impl::Event::],
964	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1066	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
965	# everything below here will not be autoprobed	1067	# everything below here will not be autoprobed
966	# as the pureperl backend should work everywhere	1068	# as the pureperl backend should work everywhere
967	# and is usually faster	1069	# and is usually faster
968	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
969	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1070	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
970	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1071	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1072	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
971	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1073	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
972	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1074	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
973	[Wx:: => AnyEvent::Impl::POE::],	1075	[Wx:: => AnyEvent::Impl::POE::],
974	[Prima:: => AnyEvent::Impl::POE::],	1076	[Prima:: => AnyEvent::Impl::POE::],
		1077	# IO::Async is just too broken - we would need workarounds for its
		1078	# byzantine signal and broken child handling, among others.
		1079	# IO::Async is rather hard to detect, as it doesn't have any
		1080	# obvious default class.
		1081	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1082	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1083	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
975	);	1084	);
976		1085
977	our %method = map +($_ => 1),	1086	our %method = map +($_ => 1),
978	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1087	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
979		1088
…		…
1006		1115
1007	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1116	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1008	my $model = "AnyEvent::Impl::$1";	1117	my $model = "AnyEvent::Impl::$1";
1009	if (eval "require $model") {	1118	if (eval "require $model") {
1010	$MODEL = $model;	1119	$MODEL = $model;
1011	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1120	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $verbose > 1;
1012	} else {	1121	} else {
1013	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1122	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $verbose;
1014	}	1123	}
1015	}	1124	}
1016		1125
1017	# check for already loaded models	1126	# check for already loaded models
1018	unless ($MODEL) {	1127	unless ($MODEL) {
…		…
1060		1169
1061	sub AUTOLOAD {	1170	sub AUTOLOAD {
1062	(my $func = $AUTOLOAD) =~ s/.*://;	1171	(my $func = $AUTOLOAD) =~ s/.*://;
1063		1172
1064	$method{$func}	1173	$method{$func}
1065	or croak "$func: not a valid method for AnyEvent objects";	1174	or Carp::croak "$func: not a valid method for AnyEvent objects";
1066		1175
1067	detect unless $MODEL;	1176	detect unless $MODEL;
1068		1177
1069	my $class = shift;	1178	my $class = shift;
1070	$class->$func (@_);	1179	$class->$func (@_);
1071	}	1180	}
1072		1181
1073	# utility function to dup a filehandle. this is used by many backends	1182	# utility function to dup a filehandle. this is used by many backends
1074	# to support binding more than one watcher per filehandle (they usually	1183	# to support binding more than one watcher per filehandle (they usually
1075	# allow only one watcher per fd, so we dup it to get a different one).	1184	# allow only one watcher per fd, so we dup it to get a different one).
1076	sub _dupfh($$$$) {	1185	sub _dupfh($$;$$) {
1077	my ($poll, $fh, $r, $w) = @_;	1186	my ($poll, $fh, $r, $w) = @_;
1078		1187
1079	# cygwin requires the fh mode to be matching, unix doesn't	1188	# cygwin requires the fh mode to be matching, unix doesn't
1080	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1189	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1081	: $poll eq "w" ? ($w, ">")
1082	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1083		1190
1084	open my $fh2, "$mode&" . fileno $fh	1191	open my $fh2, $mode, $fh
1085	or die "cannot dup() filehandle: $!,";	1192	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1086		1193
1087	# we assume CLOEXEC is already set by perl in all important cases	1194	# we assume CLOEXEC is already set by perl in all important cases
1088		1195
1089	($fh2, $rw)	1196	($fh2, $rw)
1090	}	1197	}
…		…
1141	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case	1248	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1142	} else {	1249	} else {
1143	pipe $SIGPIPE_R, $SIGPIPE_W;	1250	pipe $SIGPIPE_R, $SIGPIPE_W;
1144	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1251	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1145	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1252	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1253
		1254	# not strictly required, as $^F is normally 2, but let's make sure...
		1255	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1256	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1146	}	1257	}
1147		1258
1148	$SIGPIPE_R	1259	$SIGPIPE_R
1149	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1260	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1150
1151	# not strictly required, as $^F is normally 2, but let's make sure...
1152	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1153	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1154		1261
1155	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1262	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1156	}	1263	}
1157		1264
1158	my $signal = uc $arg{signal}	1265	my $signal = uc $arg{signal}
…		…
1171	sub AnyEvent::Base::signal::DESTROY {	1278	sub AnyEvent::Base::signal::DESTROY {
1172	my ($signal, $cb) = @{$_[0]};	1279	my ($signal, $cb) = @{$_[0]};
1173		1280
1174	delete $SIG_CB{$signal}{$cb};	1281	delete $SIG_CB{$signal}{$cb};
1175		1282
		1283	# delete doesn't work with older perls - they then
		1284	# print weird messages, or just unconditionally exit
		1285	# instead of getting the default action.
1176	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };	1286	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1177	}	1287	}
1178		1288
1179	# default implementation for ->child	1289	# default implementation for ->child
1180		1290
1181	our %PID_CB;	1291	our %PID_CB;
1182	our $CHLD_W;	1292	our $CHLD_W;
1183	our $CHLD_DELAY_W;	1293	our $CHLD_DELAY_W;
1184	our $PID_IDLE;
1185	our $WNOHANG;	1294	our $WNOHANG;
1186		1295
1187	sub _child_wait {	1296	sub _sigchld {
1188	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1297	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1189	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),	1298	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),
1190	(values %{ $PID_CB{0} \|\| {} });	1299	(values %{ $PID_CB{0} \|\| {} });
1191	}	1300	}
1192
1193	undef $PID_IDLE;
1194	}
1195
1196	sub _sigchld {
1197	# make sure we deliver these changes "synchronous" with the event loop.
1198	$CHLD_DELAY_W \|\|= AnyEvent->timer (after => 0, cb => sub {
1199	undef $CHLD_DELAY_W;
1200	&_child_wait;
1201	});
1202	}	1301	}
1203		1302
1204	sub child {	1303	sub child {
1205	my (undef, %arg) = @_;	1304	my (undef, %arg) = @_;
1206		1305
1207	defined (my $pid = $arg{pid} + 0)	1306	defined (my $pid = $arg{pid} + 0)
1208	or Carp::croak "required option 'pid' is missing";	1307	or Carp::croak "required option 'pid' is missing";
1209		1308
1210	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1309	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1211		1310
1212	unless ($WNOHANG) {
1213	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;	1311	$WNOHANG \|\|= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
1214	}
1215		1312
1216	unless ($CHLD_W) {	1313	unless ($CHLD_W) {
1217	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1314	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1218	# child could be a zombie already, so make at least one round	1315	# child could be a zombie already, so make at least one round
1219	&_sigchld;	1316	&_sigchld;
…		…
1230		1327
1231	undef $CHLD_W unless keys %PID_CB;	1328	undef $CHLD_W unless keys %PID_CB;
1232	}	1329	}
1233		1330
1234	# idle emulation is done by simply using a timer, regardless	1331	# idle emulation is done by simply using a timer, regardless
1235	# of whether the proces sis idle or not, and not letting	1332	# of whether the process is idle or not, and not letting
1236	# the callback use more than 50% of the time.	1333	# the callback use more than 50% of the time.
1237	sub idle {	1334	sub idle {
1238	my (undef, %arg) = @_;	1335	my (undef, %arg) = @_;
1239		1336
1240	my ($cb, $w, $rcb) = $arg{cb};	1337	my ($cb, $w, $rcb) = $arg{cb};
…		…
1275		1372
1276	use overload	1373	use overload
1277	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1374	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1278	fallback => 1;	1375	fallback => 1;
1279		1376
		1377	our $WAITING;
		1378
1280	sub _send {	1379	sub _send {
1281	# nop	1380	# nop
1282	}	1381	}
1283		1382
1284	sub send {	1383	sub send {
…		…
1296	sub ready {	1395	sub ready {
1297	$_[0]{_ae_sent}	1396	$_[0]{_ae_sent}
1298	}	1397	}
1299		1398
1300	sub _wait {	1399	sub _wait {
		1400	$WAITING
		1401	and !$_[0]{_ae_sent}
		1402	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1403
		1404	local $WAITING = 1;
1301	AnyEvent->one_event while !$_[0]{_ae_sent};	1405	AnyEvent->one_event while !$_[0]{_ae_sent};
1302	}	1406	}
1303		1407
1304	sub recv {	1408	sub recv {
1305	$_[0]->_wait;	1409	$_[0]->_wait;
…		…
1346	so on.	1450	so on.
1347		1451
1348	=head1 ENVIRONMENT VARIABLES	1452	=head1 ENVIRONMENT VARIABLES
1349		1453
1350	The following environment variables are used by this module or its	1454	The following environment variables are used by this module or its
1351	submodules:	1455	submodules.
		1456
		1457	Note that AnyEvent will remove I<all> environment variables starting with
		1458	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1459	enabled.
1352		1460
1353	=over 4	1461	=over 4
1354		1462
1355	=item C<PERL_ANYEVENT_VERBOSE>	1463	=item C<PERL_ANYEVENT_VERBOSE>
1356		1464
…		…
1368	=item C<PERL_ANYEVENT_STRICT>	1476	=item C<PERL_ANYEVENT_STRICT>
1369		1477
1370	AnyEvent does not do much argument checking by default, as thorough	1478	AnyEvent does not do much argument checking by default, as thorough
1371	argument checking is very costly. Setting this variable to a true value	1479	argument checking is very costly. Setting this variable to a true value
1372	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1480	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1373	check the arguments passed to most method calls. If it finds any problems	1481	check the arguments passed to most method calls. If it finds any problems,
1374	it will croak.	1482	it will croak.
1375		1483
1376	In other words, enables "strict" mode.	1484	In other words, enables "strict" mode.
1377		1485
1378	Unlike C<use strict>, it is definitely recommended ot keep it off in	1486	Unlike C<use strict>, it is definitely recommended to keep it off in
1379	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1487	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
1380	developing programs can be very useful, however.	1488	developing programs can be very useful, however.
1381		1489
1382	=item C<PERL_ANYEVENT_MODEL>	1490	=item C<PERL_ANYEVENT_MODEL>
1383		1491
…		…
1428		1536
1429	=item C<PERL_ANYEVENT_MAX_FORKS>	1537	=item C<PERL_ANYEVENT_MAX_FORKS>
1430		1538
1431	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1539	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1432	will create in parallel.	1540	will create in parallel.
		1541
		1542	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1543
		1544	The default value for the C<max_outstanding> parameter for the default DNS
		1545	resolver - this is the maximum number of parallel DNS requests that are
		1546	sent to the DNS server.
		1547
		1548	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1549
		1550	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1551	configuration) in the default resolver. When set to the empty string, no
		1552	default config will be used.
		1553
		1554	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1555
		1556	When neither C<ca_file> nor C<ca_path> was specified during
		1557	L<AnyEvent::TLS> context creation, and either of these environment
		1558	variables exist, they will be used to specify CA certificate locations
		1559	instead of a system-dependent default.
1433		1560
1434	=back	1561	=back
1435		1562
1436	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1563	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1437		1564
…		…
1682	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	1809	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1683	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	1810	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1684	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	1811	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1685	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	1812	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1686	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	1813	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		1814	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		1815	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1687	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	1816	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1688	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	1817	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1689	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	1818	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1690	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	1819	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1691		1820
…		…
1720	performance becomes really bad with lots of file descriptors (and few of	1849	performance becomes really bad with lots of file descriptors (and few of
1721	them active), of course, but this was not subject of this benchmark.	1850	them active), of course, but this was not subject of this benchmark.
1722		1851
1723	The C<Event> module has a relatively high setup and callback invocation	1852	The C<Event> module has a relatively high setup and callback invocation
1724	cost, but overall scores in on the third place.	1853	cost, but overall scores in on the third place.
		1854
		1855	C<IO::Async> performs admirably well, about on par with C<Event>, even
		1856	when using its pure perl backend.
1725		1857
1726	C<Glib>'s memory usage is quite a bit higher, but it features a	1858	C<Glib>'s memory usage is quite a bit higher, but it features a
1727	faster callback invocation and overall ends up in the same class as	1859	faster callback invocation and overall ends up in the same class as
1728	C<Event>. However, Glib scales extremely badly, doubling the number of	1860	C<Event>. However, Glib scales extremely badly, doubling the number of
1729	watchers increases the processing time by more than a factor of four,	1861	watchers increases the processing time by more than a factor of four,
…		…
1807	it to another server. This includes deleting the old timeout and creating	1939	it to another server. This includes deleting the old timeout and creating
1808	a new one that moves the timeout into the future.	1940	a new one that moves the timeout into the future.
1809		1941
1810	=head3 Results	1942	=head3 Results
1811		1943
1812	name sockets create request	1944	name sockets create request
1813	EV 20000 69.01 11.16	1945	EV 20000 69.01 11.16
1814	Perl 20000 73.32 35.87	1946	Perl 20000 73.32 35.87
		1947	IOAsync 20000 157.00 98.14 epoll
		1948	IOAsync 20000 159.31 616.06 poll
1815	Event 20000 212.62 257.32	1949	Event 20000 212.62 257.32
1816	Glib 20000 651.16 1896.30	1950	Glib 20000 651.16 1896.30
1817	POE 20000 349.67 12317.24 uses POE::Loop::Event	1951	POE 20000 349.67 12317.24 uses POE::Loop::Event
1818		1952
1819	=head3 Discussion	1953	=head3 Discussion
1820		1954
1821	This benchmark I<does> measure scalability and overall performance of the	1955	This benchmark I<does> measure scalability and overall performance of the
1822	particular event loop.	1956	particular event loop.
…		…
1824	EV is again fastest. Since it is using epoll on my system, the setup time	1958	EV is again fastest. Since it is using epoll on my system, the setup time
1825	is relatively high, though.	1959	is relatively high, though.
1826		1960
1827	Perl surprisingly comes second. It is much faster than the C-based event	1961	Perl surprisingly comes second. It is much faster than the C-based event
1828	loops Event and Glib.	1962	loops Event and Glib.
		1963
		1964	IO::Async performs very well when using its epoll backend, and still quite
		1965	good compared to Glib when using its pure perl backend.
1829		1966
1830	Event suffers from high setup time as well (look at its code and you will	1967	Event suffers from high setup time as well (look at its code and you will
1831	understand why). Callback invocation also has a high overhead compared to	1968	understand why). Callback invocation also has a high overhead compared to
1832	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	1969	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1833	uses select or poll in basically all documented configurations.	1970	uses select or poll in basically all documented configurations.
…		…
1896	=item * C-based event loops perform very well with small number of	2033	=item * C-based event loops perform very well with small number of
1897	watchers, as the management overhead dominates.	2034	watchers, as the management overhead dominates.
1898		2035
1899	=back	2036	=back
1900		2037
		2038	=head2 THE IO::Lambda BENCHMARK
		2039
		2040	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2041	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2042	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2043	shouldn't come as a surprise to anybody). As such, the benchmark is
		2044	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2045	very optimal. But how would AnyEvent compare when used without the extra
		2046	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2047
		2048	The benchmark itself creates an echo-server, and then, for 500 times,
		2049	connects to the echo server, sends a line, waits for the reply, and then
		2050	creates the next connection. This is a rather bad benchmark, as it doesn't
		2051	test the efficiency of the framework or much non-blocking I/O, but it is a
		2052	benchmark nevertheless.
		2053
		2054	name runtime
		2055	Lambda/select 0.330 sec
		2056	+ optimized 0.122 sec
		2057	Lambda/AnyEvent 0.327 sec
		2058	+ optimized 0.138 sec
		2059	Raw sockets/select 0.077 sec
		2060	POE/select, components 0.662 sec
		2061	POE/select, raw sockets 0.226 sec
		2062	POE/select, optimized 0.404 sec
		2063
		2064	AnyEvent/select/nb 0.085 sec
		2065	AnyEvent/EV/nb 0.068 sec
		2066	+state machine 0.134 sec
		2067
		2068	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2069	benchmarks actually make blocking connects and use 100% blocking I/O,
		2070	defeating the purpose of an event-based solution. All of the newly
		2071	written AnyEvent benchmarks use 100% non-blocking connects (using
		2072	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2073	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2074	generally require a lot more bookkeeping and event handling than blocking
		2075	connects (which involve a single syscall only).
		2076
		2077	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2078	offers similar expressive power as POE and IO::Lambda, using conventional
		2079	Perl syntax. This means that both the echo server and the client are 100%
		2080	non-blocking, further placing it at a disadvantage.
		2081
		2082	As you can see, the AnyEvent + EV combination even beats the
		2083	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2084	backend easily beats IO::Lambda and POE.
		2085
		2086	And even the 100% non-blocking version written using the high-level (and
		2087	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2088	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2089	in a non-blocking way.
		2090
		2091	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2092	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2093	part of the IO::lambda distribution and were used without any changes.
		2094
1901		2095
1902	=head1 SIGNALS	2096	=head1 SIGNALS
1903		2097
1904	AnyEvent currently installs handlers for these signals:	2098	AnyEvent currently installs handlers for these signals:
1905		2099
…		…
1908	=item SIGCHLD	2102	=item SIGCHLD
1909		2103
1910	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2104	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1911	emulation for event loops that do not support them natively. Also, some	2105	emulation for event loops that do not support them natively. Also, some
1912	event loops install a similar handler.	2106	event loops install a similar handler.
		2107
		2108	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2109	AnyEvent will reset it to default, to avoid losing child exit statuses.
1913		2110
1914	=item SIGPIPE	2111	=item SIGPIPE
1915		2112
1916	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2113	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1917	when AnyEvent gets loaded.	2114	when AnyEvent gets loaded.
…		…
1929		2126
1930	=back	2127	=back
1931		2128
1932	=cut	2129	=cut
1933		2130
		2131	undef $SIG{CHLD}
		2132	if $SIG{CHLD} eq 'IGNORE';
		2133
1934	$SIG{PIPE} = sub { }	2134	$SIG{PIPE} = sub { }
1935	unless defined $SIG{PIPE};	2135	unless defined $SIG{PIPE};
1936
1937		2136
1938	=head1 FORK	2137	=head1 FORK
1939		2138
1940	Most event libraries are not fork-safe. The ones who are usually are	2139	Most event libraries are not fork-safe. The ones who are usually are
1941	because they rely on inefficient but fork-safe C<select> or C<poll>	2140	because they rely on inefficient but fork-safe C<select> or C<poll>
…		…
1962	use AnyEvent;	2161	use AnyEvent;
1963		2162
1964	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2163	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1965	be used to probe what backend is used and gain other information (which is	2164	be used to probe what backend is used and gain other information (which is
1966	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2165	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1967	$ENV{PERL_ANYEGENT_STRICT}.	2166	$ENV{PERL_ANYEVENT_STRICT}.
		2167
		2168	Note that AnyEvent will remove I<all> environment variables starting with
		2169	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2170	enabled.
1968		2171
1969		2172
1970	=head1 BUGS	2173	=head1 BUGS
1971		2174
1972	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2175	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
…		…
1984	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2187	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1985		2188
1986	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2189	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1987	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2190	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1988	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2191	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1989	L<AnyEvent::Impl::POE>.	2192	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.
1990		2193
1991	Non-blocking file handles, sockets, TCP clients and	2194	Non-blocking file handles, sockets, TCP clients and
1992	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2195	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1993		2196
1994	Asynchronous DNS: L<AnyEvent::DNS>.	2197	Asynchronous DNS: L<AnyEvent::DNS>.
1995		2198
1996	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2199	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2200	L<Coro::Event>,
1997		2201
1998	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2202	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2203	L<AnyEvent::HTTP>.
1999		2204
2000		2205
2001	=head1 AUTHOR	2206	=head1 AUTHOR
2002		2207
2003	Marc Lehmann <schmorp@schmorp.de>	2208	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.208 by root, Sun Apr 26 18:12:53 2009 UTC vs. Revision 1.241 by root, Fri Jul 17 18:08:35 2009 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.208 by root, Sun Apr 26 18:12:53 2009 UTC vs.
Revision 1.241 by root, Fri Jul 17 18:08:35 2009 UTC