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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.212 by root, Sun Jun 7 16:48:38 2009 UTC vs.
Revision 1.244 by root, Fri Jul 17 23:15:57 2009 UTC

…		…
176	=head2 I/O WATCHERS	176	=head2 I/O WATCHERS
177		177
178	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
179	with the following mandatory key-value pairs as arguments:	179	with the following mandatory key-value pairs as arguments:
180		180
181	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
182	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
183	handle). Note that only file handles pointing to things for which	183	handle). Note that only file handles pointing to things for which
184	non-blocking operation makes sense are allowed. This includes sockets,	184	non-blocking operation makes sense are allowed. This includes sockets,
185	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
186	or block devices.	186	or block devices.
…		…
361	invocation, and callback invocation will be synchronous. Synchronous means	361	invocation, and callback invocation will be synchronous. Synchronous means
362	that it might take a while until the signal gets handled by the process,	362	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.	363	but it is guaranteed not to interrupt any other callbacks.
364		364
365	The main advantage of using these watchers is that you can share a signal	365	The main advantage of using these watchers is that you can share a signal
366	between multiple watchers.	366	between multiple watchers, and AnyEvent will ensure that signals will not
		367	interrupt your program at bad times.
367		368
368	This watcher might use C<%SIG>, so programs overwriting those signals	369	This watcher might use C<%SIG> (depending on the event loop used),
369	directly will likely not work correctly.	370	so programs overwriting those signals directly will likely not work
		371	correctly.
		372
		373	Also note that many event loops (e.g. Glib, Tk, Qt, IO::Async) do not
		374	support attaching callbacks to signals, which is a pity, as you cannot do
		375	race-free signal handling in perl. AnyEvent will try to do it's best, but
		376	in some cases, signals will be delayed. The maximum time a signal might
		377	be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10
		378	seconds). This variable can be changed only before the first signal
		379	watcher is created, and should be left alone otherwise. Higher values
		380	will cause fewer spurious wake-ups, which is better for power and CPU
		381	saving. All these problems can be avoided by installing the optional
		382	L<Async::Interrupt> module.
370		383
371	Example: exit on SIGINT	384	Example: exit on SIGINT
372		385
373	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	386	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
374		387
…		…
392		405
393	There is a slight catch to child watchers, however: you usually start them	406	There is a slight catch to child watchers, however: you usually start them
394	I<after> the child process was created, and this means the process could	407	I<after> the child process was created, and this means the process could
395	have exited already (and no SIGCHLD will be sent anymore).	408	have exited already (and no SIGCHLD will be sent anymore).
396		409
397	Not all event models handle this correctly (POE doesn't), but even for	410	Not all event models handle this correctly (neither POE nor IO::Async do,
		411	see their AnyEvent::Impl manpages for details), but even for event models
398	event models that I<do> handle this correctly, they usually need to be	412	that I<do> handle this correctly, they usually need to be loaded before
399	loaded before the process exits (i.e. before you fork in the first place).	413	the process exits (i.e. before you fork in the first place). AnyEvent's
		414	pure perl event loop handles all cases correctly regardless of when you
		415	start the watcher.
400		416
401	This means you cannot create a child watcher as the very first thing in an	417	This means you cannot create a child watcher as the very first
402	AnyEvent program, you I<have> to create at least one watcher before you	418	thing in an AnyEvent program, you I<have> to create at least one
403	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	419	watcher before you C<fork> the child (alternatively, you can call
		420	C<AnyEvent::detect>).
		421
		422	As most event loops do not support waiting for child events, they will be
		423	emulated by AnyEvent in most cases, in which the latency and race problems
		424	mentioned in the description of signal watchers apply.
404		425
405	Example: fork a process and wait for it	426	Example: fork a process and wait for it
406		427
407	my $done = AnyEvent->condvar;	428	my $done = AnyEvent->condvar;
408		429
…		…
459		480
460	If you are familiar with some event loops you will know that all of them	481	If you are familiar with some event loops you will know that all of them
461	require you to run some blocking "loop", "run" or similar function that	482	require you to run some blocking "loop", "run" or similar function that
462	will actively watch for new events and call your callbacks.	483	will actively watch for new events and call your callbacks.
463		484
464	AnyEvent is different, it expects somebody else to run the event loop and	485	AnyEvent is slightly different: it expects somebody else to run the event
465	will only block when necessary (usually when told by the user).	486	loop and will only block when necessary (usually when told by the user).
466		487
467	The instrument to do that is called a "condition variable", so called	488	The instrument to do that is called a "condition variable", so called
468	because they represent a condition that must become true.	489	because they represent a condition that must become true.
469		490
		491	Now is probably a good time to look at the examples further below.
		492
470	Condition variables can be created by calling the C<< AnyEvent->condvar	493	Condition variables can be created by calling the C<< AnyEvent->condvar
471	>> method, usually without arguments. The only argument pair allowed is	494	>> method, usually without arguments. The only argument pair allowed is
472
473	C<cb>, which specifies a callback to be called when the condition variable	495	C<cb>, which specifies a callback to be called when the condition variable
474	becomes true, with the condition variable as the first argument (but not	496	becomes true, with the condition variable as the first argument (but not
475	the results).	497	the results).
476		498
477	After creation, the condition variable is "false" until it becomes "true"	499	After creation, the condition variable is "false" until it becomes "true"
…		…
526	after => 1,	548	after => 1,
527	cb => sub { $result_ready->send },	549	cb => sub { $result_ready->send },
528	);	550	);
529		551
530	# this "blocks" (while handling events) till the callback	552	# this "blocks" (while handling events) till the callback
531	# calls send	553	# calls -<send
532	$result_ready->recv;	554	$result_ready->recv;
533		555
534	Example: wait for a timer, but take advantage of the fact that	556	Example: wait for a timer, but take advantage of the fact that condition
535	condition variables are also code references.	557	variables are also callable directly.
536		558
537	my $done = AnyEvent->condvar;	559	my $done = AnyEvent->condvar;
538	my $delay = AnyEvent->timer (after => 5, cb => $done);	560	my $delay = AnyEvent->timer (after => 5, cb => $done);
539	$done->recv;	561	$done->recv;
540		562
…		…
546		568
547	...	569	...
548		570
549	my @info = $couchdb->info->recv;	571	my @info = $couchdb->info->recv;
550		572
551	And this is how you would just ste a callback to be called whenever the	573	And this is how you would just set a callback to be called whenever the
552	results are available:	574	results are available:
553		575
554	$couchdb->info->cb (sub {	576	$couchdb->info->cb (sub {
555	my @info = $_[0]->recv;	577	my @info = $_[0]->recv;
556	});	578	});
…		…
574	immediately from within send.	596	immediately from within send.
575		597
576	Any arguments passed to the C<send> call will be returned by all	598	Any arguments passed to the C<send> call will be returned by all
577	future C<< ->recv >> calls.	599	future C<< ->recv >> calls.
578		600
579	Condition variables are overloaded so one can call them directly	601	Condition variables are overloaded so one can call them directly (as if
580	(as a code reference). Calling them directly is the same as calling	602	they were a code reference). Calling them directly is the same as calling
581	C<send>. Note, however, that many C-based event loops do not handle	603	C<send>.
582	overloading, so as tempting as it may be, passing a condition variable
583	instead of a callback does not work. Both the pure perl and EV loops
584	support overloading, however, as well as all functions that use perl to
585	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
586	example).
587		604
588	=item $cv->croak ($error)	605	=item $cv->croak ($error)
589		606
590	Similar to send, but causes all call's to C<< ->recv >> to invoke	607	Similar to send, but causes all call's to C<< ->recv >> to invoke
591	C<Carp::croak> with the given error message/object/scalar.	608	C<Carp::croak> with the given error message/object/scalar.
592		609
593	This can be used to signal any errors to the condition variable	610	This can be used to signal any errors to the condition variable
594	user/consumer.	611	user/consumer. Doing it this way instead of calling C<croak> directly
		612	delays the error detetcion, but has the overwhelmign advantage that it
		613	diagnoses the error at the place where the result is expected, and not
		614	deep in some event clalback without connection to the actual code causing
		615	the problem.
595		616
596	=item $cv->begin ([group callback])	617	=item $cv->begin ([group callback])
597		618
598	=item $cv->end	619	=item $cv->end
599
600	These two methods are EXPERIMENTAL and MIGHT CHANGE.
601		620
602	These two methods can be used to combine many transactions/events into	621	These two methods can be used to combine many transactions/events into
603	one. For example, a function that pings many hosts in parallel might want	622	one. For example, a function that pings many hosts in parallel might want
604	to use a condition variable for the whole process.	623	to use a condition variable for the whole process.
605		624
…		…
607	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	626	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
608	>>, the (last) callback passed to C<begin> will be executed. That callback	627	>>, the (last) callback passed to C<begin> will be executed. That callback
609	is I<supposed> to call C<< ->send >>, but that is not required. If no	628	is I<supposed> to call C<< ->send >>, but that is not required. If no
610	callback was set, C<send> will be called without any arguments.	629	callback was set, C<send> will be called without any arguments.
611		630
612	Let's clarify this with the ping example:	631	You can think of C<< $cv->send >> giving you an OR condition (one call
		632	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		633	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		634
		635	Let's start with a simple example: you have two I/O watchers (for example,
		636	STDOUT and STDERR for a program), and you want to wait for both streams to
		637	close before activating a condvar:
		638
		639	my $cv = AnyEvent->condvar;
		640
		641	$cv->begin; # first watcher
		642	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		643	defined sysread $fh1, my $buf, 4096
		644	or $cv->end;
		645	});
		646
		647	$cv->begin; # second watcher
		648	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		649	defined sysread $fh2, my $buf, 4096
		650	or $cv->end;
		651	});
		652
		653	$cv->recv;
		654
		655	This works because for every event source (EOF on file handle), there is
		656	one call to C<begin>, so the condvar waits for all calls to C<end> before
		657	sending.
		658
		659	The ping example mentioned above is slightly more complicated, as the
		660	there are results to be passwd back, and the number of tasks that are
		661	begung can potentially be zero:
613		662
614	my $cv = AnyEvent->condvar;	663	my $cv = AnyEvent->condvar;
615		664
616	my %result;	665	my %result;
617	$cv->begin (sub { $cv->send (\%result) });	666	$cv->begin (sub { $cv->send (\%result) });
…		…
637	loop, which serves two important purposes: first, it sets the callback	686	loop, which serves two important purposes: first, it sets the callback
638	to be called once the counter reaches C<0>, and second, it ensures that	687	to be called once the counter reaches C<0>, and second, it ensures that
639	C<send> is called even when C<no> hosts are being pinged (the loop	688	C<send> is called even when C<no> hosts are being pinged (the loop
640	doesn't execute once).	689	doesn't execute once).
641		690
642	This is the general pattern when you "fan out" into multiple subrequests:	691	This is the general pattern when you "fan out" into multiple (but
643	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	692	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
644	is called at least once, and then, for each subrequest you start, call	693	the callback and ensure C<end> is called at least once, and then, for each
645	C<begin> and for each subrequest you finish, call C<end>.	694	subrequest you start, call C<begin> and for each subrequest you finish,
		695	call C<end>.
646		696
647	=back	697	=back
648		698
649	=head3 METHODS FOR CONSUMERS	699	=head3 METHODS FOR CONSUMERS
650		700
…		…
666	function will call C<croak>.	716	function will call C<croak>.
667		717
668	In list context, all parameters passed to C<send> will be returned,	718	In list context, all parameters passed to C<send> will be returned,
669	in scalar context only the first one will be returned.	719	in scalar context only the first one will be returned.
670		720
		721	Note that doing a blocking wait in a callback is not supported by any
		722	event loop, that is, recursive invocation of a blocking C<< ->recv
		723	>> is not allowed, and the C<recv> call will C<croak> if such a
		724	condition is detected. This condition can be slightly loosened by using
		725	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		726	any thread that doesn't run the event loop itself.
		727
671	Not all event models support a blocking wait - some die in that case	728	Not all event models support a blocking wait - some die in that case
672	(programs might want to do that to stay interactive), so I<if you are	729	(programs might want to do that to stay interactive), so I<if you are
673	using this from a module, never require a blocking wait>, but let the	730	using this from a module, never require a blocking wait>. Instead, let the
674	caller decide whether the call will block or not (for example, by coupling	731	caller decide whether the call will block or not (for example, by coupling
675	condition variables with some kind of request results and supporting	732	condition variables with some kind of request results and supporting
676	callbacks so the caller knows that getting the result will not block,	733	callbacks so the caller knows that getting the result will not block,
677	while still supporting blocking waits if the caller so desires).	734	while still supporting blocking waits if the caller so desires).
678		735
679	Another reason I<never> to C<< ->recv >> in a module is that you cannot
680	sensibly have two C<< ->recv >>'s in parallel, as that would require
681	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
682	can supply.
683
684	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
685	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
686	versions and also integrates coroutines into AnyEvent, making blocking
687	C<< ->recv >> calls perfectly safe as long as they are done from another
688	coroutine (one that doesn't run the event loop).
689
690	You can ensure that C<< -recv >> never blocks by setting a callback and	736	You can ensure that C<< -recv >> never blocks by setting a callback and
691	only calling C<< ->recv >> from within that callback (or at a later	737	only calling C<< ->recv >> from within that callback (or at a later
692	time). This will work even when the event loop does not support blocking	738	time). This will work even when the event loop does not support blocking
693	waits otherwise.	739	waits otherwise.
694		740
…		…
707	variable itself. Calling C<recv> inside the callback or at any later time	753	variable itself. Calling C<recv> inside the callback or at any later time
708	is guaranteed not to block.	754	is guaranteed not to block.
709		755
710	=back	756	=back
711		757
		758	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		759
		760	The available backend classes are (every class has its own manpage):
		761
		762	=over 4
		763
		764	=item Backends that are autoprobed when no other event loop can be found.
		765
		766	EV is the preferred backend when no other event loop seems to be in
		767	use. If EV is not installed, then AnyEvent will try Event, and, failing
		768	that, will fall back to its own pure-perl implementation, which is
		769	available everywhere as it comes with AnyEvent itself.
		770
		771	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		772	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		773	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		774
		775	=item Backends that are transparently being picked up when they are used.
		776
		777	These will be used when they are currently loaded when the first watcher
		778	is created, in which case it is assumed that the application is using
		779	them. This means that AnyEvent will automatically pick the right backend
		780	when the main program loads an event module before anything starts to
		781	create watchers. Nothing special needs to be done by the main program.
		782
		783	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		784	AnyEvent::Impl::Tk based on Tk, very broken.
		785	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		786	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		787
		788	=item Backends with special needs.
		789
		790	Qt requires the Qt::Application to be instantiated first, but will
		791	otherwise be picked up automatically. As long as the main program
		792	instantiates the application before any AnyEvent watchers are created,
		793	everything should just work.
		794
		795	AnyEvent::Impl::Qt based on Qt.
		796
		797	Support for IO::Async can only be partial, as it is too broken and
		798	architecturally limited to even support the AnyEvent API. It also
		799	is the only event loop that needs the loop to be set explicitly, so
		800	it can only be used by a main program knowing about AnyEvent. See
		801	L<AnyEvent::Impl::Async> for the gory details.
		802
		803	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		804
		805	=item Event loops that are indirectly supported via other backends.
		806
		807	Some event loops can be supported via other modules:
		808
		809	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		810
		811	B<WxWidgets> has no support for watching file handles. However, you can
		812	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		813	polls 20 times per second, which was considered to be too horrible to even
		814	consider for AnyEvent.
		815
		816	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		817	backend, so it can be supported through POE.
		818
		819	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		820	load L<POE> when detecting them, in the hope that POE will pick them up,
		821	in which case everything will be automatic.
		822
		823	=back
		824
712	=head1 GLOBAL VARIABLES AND FUNCTIONS	825	=head1 GLOBAL VARIABLES AND FUNCTIONS
713		826
		827	These are not normally required to use AnyEvent, but can be useful to
		828	write AnyEvent extension modules.
		829
714	=over 4	830	=over 4
715		831
716	=item $AnyEvent::MODEL	832	=item $AnyEvent::MODEL
717		833
718	Contains C<undef> until the first watcher is being created. Then it	834	Contains C<undef> until the first watcher is being created, before the
		835	backend has been autodetected.
		836
719	contains the event model that is being used, which is the name of the	837	Afterwards it contains the event model that is being used, which is the
720	Perl class implementing the model. This class is usually one of the	838	name of the Perl class implementing the model. This class is usually one
721	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	839	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
722	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	840	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
723		841	will be C<urxvt::anyevent>).
724	The known classes so far are:
725
726	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
727	AnyEvent::Impl::Event based on Event, second best choice.
728	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
729	AnyEvent::Impl::Glib based on Glib, third-best choice.
730	AnyEvent::Impl::Tk based on Tk, very bad choice.
731	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
732	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
733	AnyEvent::Impl::POE based on POE, not generic enough for full support.
734
735	There is no support for WxWidgets, as WxWidgets has no support for
736	watching file handles. However, you can use WxWidgets through the
737	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
738	second, which was considered to be too horrible to even consider for
739	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
740	it's adaptor.
741
742	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
743	autodetecting them.
744		842
745	=item AnyEvent::detect	843	=item AnyEvent::detect
746		844
747	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	845	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
748	if necessary. You should only call this function right before you would	846	if necessary. You should only call this function right before you would
749	have created an AnyEvent watcher anyway, that is, as late as possible at	847	have created an AnyEvent watcher anyway, that is, as late as possible at
750	runtime.	848	runtime, and not e.g. while initialising of your module.
		849
		850	If you need to do some initialisation before AnyEvent watchers are
		851	created, use C<post_detect>.
751		852
752	=item $guard = AnyEvent::post_detect { BLOCK }	853	=item $guard = AnyEvent::post_detect { BLOCK }
753		854
754	Arranges for the code block to be executed as soon as the event model is	855	Arranges for the code block to be executed as soon as the event model is
755	autodetected (or immediately if this has already happened).	856	autodetected (or immediately if this has already happened).
		857
		858	The block will be executed I<after> the actual backend has been detected
		859	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		860	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		861	other initialisations - see the sources of L<AnyEvent::Strict> or
		862	L<AnyEvent::AIO> to see how this is used.
		863
		864	The most common usage is to create some global watchers, without forcing
		865	event module detection too early, for example, L<AnyEvent::AIO> creates
		866	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		867	avoid autodetecting the event module at load time.
756		868
757	If called in scalar or list context, then it creates and returns an object	869	If called in scalar or list context, then it creates and returns an object
758	that automatically removes the callback again when it is destroyed. See	870	that automatically removes the callback again when it is destroyed. See
759	L<Coro::BDB> for a case where this is useful.	871	L<Coro::BDB> for a case where this is useful.
760		872
…		…
763	If there are any code references in this array (you can C<push> to it	875	If there are any code references in this array (you can C<push> to it
764	before or after loading AnyEvent), then they will called directly after	876	before or after loading AnyEvent), then they will called directly after
765	the event loop has been chosen.	877	the event loop has been chosen.
766		878
767	You should check C<$AnyEvent::MODEL> before adding to this array, though:	879	You should check C<$AnyEvent::MODEL> before adding to this array, though:
768	if it contains a true value then the event loop has already been detected,	880	if it is defined then the event loop has already been detected, and the
769	and the array will be ignored.	881	array will be ignored.
770		882
771	Best use C<AnyEvent::post_detect { BLOCK }> instead.	883	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		884	it,as it takes care of these details.
		885
		886	This variable is mainly useful for modules that can do something useful
		887	when AnyEvent is used and thus want to know when it is initialised, but do
		888	not need to even load it by default. This array provides the means to hook
		889	into AnyEvent passively, without loading it.
772		890
773	=back	891	=back
774		892
775	=head1 WHAT TO DO IN A MODULE	893	=head1 WHAT TO DO IN A MODULE
776		894
…		…
831		949
832		950
833	=head1 OTHER MODULES	951	=head1 OTHER MODULES
834		952
835	The following is a non-exhaustive list of additional modules that use	953	The following is a non-exhaustive list of additional modules that use
836	AnyEvent and can therefore be mixed easily with other AnyEvent modules	954	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
837	in the same program. Some of the modules come with AnyEvent, some are	955	modules and other event loops in the same program. Some of the modules
838	available via CPAN.	956	come with AnyEvent, most are available via CPAN.
839		957
840	=over 4	958	=over 4
841		959
842	=item L<AnyEvent::Util>	960	=item L<AnyEvent::Util>
843		961
…		…
852		970
853	=item L<AnyEvent::Handle>	971	=item L<AnyEvent::Handle>
854		972
855	Provide read and write buffers, manages watchers for reads and writes,	973	Provide read and write buffers, manages watchers for reads and writes,
856	supports raw and formatted I/O, I/O queued and fully transparent and	974	supports raw and formatted I/O, I/O queued and fully transparent and
857	non-blocking SSL/TLS.	975	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
858		976
859	=item L<AnyEvent::DNS>	977	=item L<AnyEvent::DNS>
860		978
861	Provides rich asynchronous DNS resolver capabilities.	979	Provides rich asynchronous DNS resolver capabilities.
862		980
…		…
890		1008
891	=item L<AnyEvent::GPSD>	1009	=item L<AnyEvent::GPSD>
892		1010
893	A non-blocking interface to gpsd, a daemon delivering GPS information.	1011	A non-blocking interface to gpsd, a daemon delivering GPS information.
894		1012
		1013	=item L<AnyEvent::IRC>
		1014
		1015	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1016
		1017	=item L<AnyEvent::XMPP>
		1018
		1019	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1020	Net::XMPP2>.
		1021
895	=item L<AnyEvent::IGS>	1022	=item L<AnyEvent::IGS>
896		1023
897	A non-blocking interface to the Internet Go Server protocol (used by	1024	A non-blocking interface to the Internet Go Server protocol (used by
898	L<App::IGS>).	1025	L<App::IGS>).
899		1026
900	=item L<AnyEvent::IRC>
901
902	AnyEvent based IRC client module family (replacing the older Net::IRC3).
903
904	=item L<Net::XMPP2>
905
906	AnyEvent based XMPP (Jabber protocol) module family.
907
908	=item L<Net::FCP>	1027	=item L<Net::FCP>
909		1028
910	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1029	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
911	of AnyEvent.	1030	of AnyEvent.
912		1031
…		…
916		1035
917	=item L<Coro>	1036	=item L<Coro>
918		1037
919	Has special support for AnyEvent via L<Coro::AnyEvent>.	1038	Has special support for AnyEvent via L<Coro::AnyEvent>.
920		1039
921	=item L<IO::Lambda>
922
923	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
924
925	=back	1040	=back
926		1041
927	=cut	1042	=cut
928		1043
929	package AnyEvent;	1044	package AnyEvent;
930		1045
		1046	# basically a tuned-down version of common::sense
		1047	sub common_sense {
931	no warnings;	1048	# no warnings
		1049	${^WARNING_BITS} ^= ${^WARNING_BITS};
932	use strict qw(vars subs);	1050	# use strict vars subs
		1051	$^H \|= 0x00000600;
		1052	}
933		1053
		1054	BEGIN { AnyEvent::common_sense }
		1055
934	use Carp;	1056	use Carp ();
935		1057
936	our $VERSION = 4.411;	1058	our $VERSION = 4.83;
937	our $MODEL;	1059	our $MODEL;
938		1060
939	our $AUTOLOAD;	1061	our $AUTOLOAD;
940	our @ISA;	1062	our @ISA;
941		1063
942	our @REGISTRY;	1064	our @REGISTRY;
943		1065
944	our $WIN32;	1066	our $WIN32;
945		1067
		1068	our $VERBOSE;
		1069
946	BEGIN {	1070	BEGIN {
947	my $win32 = ! ! ($^O =~ /mswin32/i);	1071	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
948	eval "sub WIN32(){ $win32 }";	1072	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
949	}
950		1073
		1074	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1075	if ${^TAINT};
		1076
951	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1077	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1078
		1079	}
		1080
		1081	our $MAX_SIGNAL_LATENCY = 10;
952		1082
953	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred	1083	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
954		1084
955	{	1085	{
956	my $idx;	1086	my $idx;
…		…
964	[Event:: => AnyEvent::Impl::Event::],	1094	[Event:: => AnyEvent::Impl::Event::],
965	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1095	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
966	# everything below here will not be autoprobed	1096	# everything below here will not be autoprobed
967	# as the pureperl backend should work everywhere	1097	# as the pureperl backend should work everywhere
968	# and is usually faster	1098	# and is usually faster
969	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
970	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1099	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
971	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1100	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1101	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
972	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1102	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
973	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1103	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
974	[Wx:: => AnyEvent::Impl::POE::],	1104	[Wx:: => AnyEvent::Impl::POE::],
975	[Prima:: => AnyEvent::Impl::POE::],	1105	[Prima:: => AnyEvent::Impl::POE::],
		1106	# IO::Async is just too broken - we would need workarounds for its
		1107	# byzantine signal and broken child handling, among others.
		1108	# IO::Async is rather hard to detect, as it doesn't have any
		1109	# obvious default class.
		1110	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1111	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1112	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
976	);	1113	);
977		1114
978	our %method = map +($_ => 1),	1115	our %method = map +($_ => 1),
979	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1116	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
980		1117
…		…
1000	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1137	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1001	}	1138	}
1002		1139
1003	sub detect() {	1140	sub detect() {
1004	unless ($MODEL) {	1141	unless ($MODEL) {
1005	no strict 'refs';
1006	local $SIG{__DIE__};	1142	local $SIG{__DIE__};
1007		1143
1008	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1144	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1009	my $model = "AnyEvent::Impl::$1";	1145	my $model = "AnyEvent::Impl::$1";
1010	if (eval "require $model") {	1146	if (eval "require $model") {
1011	$MODEL = $model;	1147	$MODEL = $model;
1012	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1148	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1013	} else {	1149	} else {
1014	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1150	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1015	}	1151	}
1016	}	1152	}
1017		1153
1018	# check for already loaded models	1154	# check for already loaded models
1019	unless ($MODEL) {	1155	unless ($MODEL) {
1020	for (@REGISTRY, @models) {	1156	for (@REGISTRY, @models) {
1021	my ($package, $model) = @$_;	1157	my ($package, $model) = @$_;
1022	if (${"$package\::VERSION"} > 0) {	1158	if (${"$package\::VERSION"} > 0) {
1023	if (eval "require $model") {	1159	if (eval "require $model") {
1024	$MODEL = $model;	1160	$MODEL = $model;
1025	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1161	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1026	last;	1162	last;
1027	}	1163	}
1028	}	1164	}
1029	}	1165	}
1030		1166
…		…
1035	my ($package, $model) = @$_;	1171	my ($package, $model) = @$_;
1036	if (eval "require $package"	1172	if (eval "require $package"
1037	and ${"$package\::VERSION"} > 0	1173	and ${"$package\::VERSION"} > 0
1038	and eval "require $model") {	1174	and eval "require $model") {
1039	$MODEL = $model;	1175	$MODEL = $model;
1040	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1176	warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1041	last;	1177	last;
1042	}	1178	}
1043	}	1179	}
1044		1180
1045	$MODEL	1181	$MODEL
…		…
1061		1197
1062	sub AUTOLOAD {	1198	sub AUTOLOAD {
1063	(my $func = $AUTOLOAD) =~ s/.*://;	1199	(my $func = $AUTOLOAD) =~ s/.*://;
1064		1200
1065	$method{$func}	1201	$method{$func}
1066	or croak "$func: not a valid method for AnyEvent objects";	1202	or Carp::croak "$func: not a valid method for AnyEvent objects";
1067		1203
1068	detect unless $MODEL;	1204	detect unless $MODEL;
1069		1205
1070	my $class = shift;	1206	my $class = shift;
1071	$class->$func (@_);	1207	$class->$func (@_);
1072	}	1208	}
1073		1209
1074	# utility function to dup a filehandle. this is used by many backends	1210	# utility function to dup a filehandle. this is used by many backends
1075	# to support binding more than one watcher per filehandle (they usually	1211	# to support binding more than one watcher per filehandle (they usually
1076	# allow only one watcher per fd, so we dup it to get a different one).	1212	# allow only one watcher per fd, so we dup it to get a different one).
1077	sub _dupfh($$$$) {	1213	sub _dupfh($$;$$) {
1078	my ($poll, $fh, $r, $w) = @_;	1214	my ($poll, $fh, $r, $w) = @_;
1079		1215
1080	# cygwin requires the fh mode to be matching, unix doesn't	1216	# cygwin requires the fh mode to be matching, unix doesn't
1081	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1217	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1082	: $poll eq "w" ? ($w, ">")
1083	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1084		1218
1085	open my $fh2, "$mode&" . fileno $fh	1219	open my $fh2, $mode, $fh
1086	or die "cannot dup() filehandle: $!,";	1220	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1087		1221
1088	# we assume CLOEXEC is already set by perl in all important cases	1222	# we assume CLOEXEC is already set by perl in all important cases
1089		1223
1090	($fh2, $rw)	1224	($fh2, $rw)
1091	}	1225	}
1092		1226
1093	package AnyEvent::Base;	1227	package AnyEvent::Base;
1094		1228
1095	# default implementations for many methods	1229	# default implementations for many methods
1096		1230
1097	BEGIN {	1231	sub _time {
		1232	# probe for availability of Time::HiRes
1098	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1233	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1234	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1099	*_time = \&Time::HiRes::time;	1235	*_time = \&Time::HiRes::time;
1100	# if (eval "use POSIX (); (POSIX::times())...	1236	# if (eval "use POSIX (); (POSIX::times())...
1101	} else {	1237	} else {
		1238	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1102	*_time = sub { time }; # epic fail	1239	*_time = sub { time }; # epic fail
1103	}	1240	}
		1241
		1242	&_time
1104	}	1243	}
1105		1244
1106	sub time { _time }	1245	sub time { _time }
1107	sub now { _time }	1246	sub now { _time }
1108	sub now_update { }	1247	sub now_update { }
…		…
1113	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1252	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1114	}	1253	}
1115		1254
1116	# default implementation for ->signal	1255	# default implementation for ->signal
1117		1256
		1257	our $HAVE_ASYNC_INTERRUPT;
1118	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1258	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1259	our (%SIG_ASY, %SIG_ASY_W);
		1260	our ($SIG_COUNT, $SIG_TW);
1119		1261
1120	sub _signal_exec {	1262	sub _signal_exec {
		1263	$HAVE_ASYNC_INTERRUPT
		1264	? $SIGPIPE_R->drain
1121	sysread $SIGPIPE_R, my $dummy, 4;	1265	: sysread $SIGPIPE_R, my $dummy, 9;
1122		1266
1123	while (%SIG_EV) {	1267	while (%SIG_EV) {
1124	for (keys %SIG_EV) {	1268	for (keys %SIG_EV) {
1125	delete $SIG_EV{$_};	1269	delete $SIG_EV{$_};
1126	$_->() for values %{ $SIG_CB{$_} \|\| {} };	1270	$_->() for values %{ $SIG_CB{$_} \|\| {} };
1127	}	1271	}
1128	}	1272	}
1129	}	1273	}
1130		1274
		1275	sub _signal {
		1276	my (undef, %arg) = @_;
		1277
		1278	my $signal = uc $arg{signal}
		1279	or Carp::croak "required option 'signal' is missing";
		1280
		1281	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1282
		1283	if ($HAVE_ASYNC_INTERRUPT) {
		1284	# async::interrupt
		1285
		1286	$SIG_ASY{$signal} \|\|= do {
		1287	my $asy = new Async::Interrupt
		1288	cb => sub { undef $SIG_EV{$signal} },
		1289	signal => $signal,
		1290	pipe => [$SIGPIPE_R->filenos],
		1291	;
		1292	$asy->pipe_autodrain (0);
		1293
		1294	$asy
		1295	};
		1296
		1297	} else {
		1298	# pure perl
		1299
		1300	$SIG{$signal} \|\|= sub {
		1301	local $!;
		1302	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1303	undef $SIG_EV{$signal};
		1304	};
		1305
		1306	# can't do signal processing without introducing races in pure perl,
		1307	# so limit the signal latency.
		1308	++$SIG_COUNT;
		1309	$SIG_TW \|\|= AnyEvent->timer (
		1310	after => $MAX_SIGNAL_LATENCY,
		1311	interval => $MAX_SIGNAL_LATENCY,
		1312	cb => sub { }, # just for the PERL_ASYNC_CHECK
		1313	);
		1314	}
		1315
		1316	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1317	}
		1318
1131	sub signal {	1319	sub signal {
1132	my (undef, %arg) = @_;	1320	# probe for availability of Async::Interrupt
		1321	if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
		1322	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1133		1323
1134	unless ($SIGPIPE_R) {	1324	$HAVE_ASYNC_INTERRUPT = 1;
		1325	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1326	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
		1327
		1328	} else {
		1329	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1330
1135	require Fcntl;	1331	require Fcntl;
1136		1332
1137	if (AnyEvent::WIN32) {	1333	if (AnyEvent::WIN32) {
1138	require AnyEvent::Util;	1334	require AnyEvent::Util;
1139		1335
…		…
1154	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1350	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1155		1351
1156	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1352	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1157	}	1353	}
1158		1354
1159	my $signal = uc $arg{signal}	1355	*signal = \&_signal;
1160	or Carp::croak "required option 'signal' is missing";	1356	&signal
1161
1162	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1163	$SIG{$signal} \|\|= sub {
1164	local $!;
1165	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1166	undef $SIG_EV{$signal};
1167	};
1168
1169	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1170	}	1357	}
1171		1358
1172	sub AnyEvent::Base::signal::DESTROY {	1359	sub AnyEvent::Base::signal::DESTROY {
1173	my ($signal, $cb) = @{$_[0]};	1360	my ($signal, $cb) = @{$_[0]};
		1361
		1362	undef $SIG_TW
		1363	unless --$SIG_COUNT;
1174		1364
1175	delete $SIG_CB{$signal}{$cb};	1365	delete $SIG_CB{$signal}{$cb};
1176		1366
1177	# delete doesn't work with older perls - they then	1367	# delete doesn't work with older perls - they then
1178	# print weird messages, or just unconditionally exit	1368	# print weird messages, or just unconditionally exit
1179	# instead of getting the default action.	1369	# instead of getting the default action.
		1370	undef $SIG{$signal}
1180	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };	1371	unless keys %{ $SIG_CB{$signal} };
1181	}	1372	}
1182		1373
1183	# default implementation for ->child	1374	# default implementation for ->child
1184		1375
1185	our %PID_CB;	1376	our %PID_CB;
…		…
1187	our $CHLD_DELAY_W;	1378	our $CHLD_DELAY_W;
1188	our $WNOHANG;	1379	our $WNOHANG;
1189		1380
1190	sub _sigchld {	1381	sub _sigchld {
1191	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1382	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
		1383	$_->($pid, $?)
1192	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),	1384	for values %{ $PID_CB{$pid} \|\| {} },
1193	(values %{ $PID_CB{0} \|\| {} });	1385	values %{ $PID_CB{0} \|\| {} };
1194	}	1386	}
1195	}	1387	}
1196		1388
1197	sub child {	1389	sub child {
1198	my (undef, %arg) = @_;	1390	my (undef, %arg) = @_;
…		…
1200	defined (my $pid = $arg{pid} + 0)	1392	defined (my $pid = $arg{pid} + 0)
1201	or Carp::croak "required option 'pid' is missing";	1393	or Carp::croak "required option 'pid' is missing";
1202		1394
1203	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1395	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1204		1396
		1397	# WNOHANG is almost cetrainly 1 everywhere
		1398	$WNOHANG \|\|= $^O =~ /^(?:openbsd\|netbsd\|linux\|freebsd\|cygwin\|MSWin32)$/
		1399	? 1
1205	$WNOHANG \|\|= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;	1400	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
1206		1401
1207	unless ($CHLD_W) {	1402	unless ($CHLD_W) {
1208	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1403	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1209	# child could be a zombie already, so make at least one round	1404	# child could be a zombie already, so make at least one round
1210	&_sigchld;	1405	&_sigchld;
…		…
1262		1457
1263	our @ISA = AnyEvent::CondVar::Base::;	1458	our @ISA = AnyEvent::CondVar::Base::;
1264		1459
1265	package AnyEvent::CondVar::Base;	1460	package AnyEvent::CondVar::Base;
1266		1461
1267	use overload	1462	#use overload
1268	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1463	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1269	fallback => 1;	1464	# fallback => 1;
		1465
		1466	# save 300+ kilobytes by dirtily hardcoding overloading
		1467	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1468	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1469	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1470	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1471
		1472	our $WAITING;
1270		1473
1271	sub _send {	1474	sub _send {
1272	# nop	1475	# nop
1273	}	1476	}
1274		1477
…		…
1287	sub ready {	1490	sub ready {
1288	$_[0]{_ae_sent}	1491	$_[0]{_ae_sent}
1289	}	1492	}
1290		1493
1291	sub _wait {	1494	sub _wait {
		1495	$WAITING
		1496	and !$_[0]{_ae_sent}
		1497	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1498
		1499	local $WAITING = 1;
1292	AnyEvent->one_event while !$_[0]{_ae_sent};	1500	AnyEvent->one_event while !$_[0]{_ae_sent};
1293	}	1501	}
1294		1502
1295	sub recv {	1503	sub recv {
1296	$_[0]->_wait;	1504	$_[0]->_wait;
…		…
1337	so on.	1545	so on.
1338		1546
1339	=head1 ENVIRONMENT VARIABLES	1547	=head1 ENVIRONMENT VARIABLES
1340		1548
1341	The following environment variables are used by this module or its	1549	The following environment variables are used by this module or its
1342	submodules:	1550	submodules.
		1551
		1552	Note that AnyEvent will remove I<all> environment variables starting with
		1553	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1554	enabled.
1343		1555
1344	=over 4	1556	=over 4
1345		1557
1346	=item C<PERL_ANYEVENT_VERBOSE>	1558	=item C<PERL_ANYEVENT_VERBOSE>
1347		1559
…		…
1354	C<PERL_ANYEVENT_MODEL>.	1566	C<PERL_ANYEVENT_MODEL>.
1355		1567
1356	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1568	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1357	model it chooses.	1569	model it chooses.
1358		1570
		1571	When set to C<8> or higher, then AnyEvent will report extra information on
		1572	which optional modules it loads and how it implements certain features.
		1573
1359	=item C<PERL_ANYEVENT_STRICT>	1574	=item C<PERL_ANYEVENT_STRICT>
1360		1575
1361	AnyEvent does not do much argument checking by default, as thorough	1576	AnyEvent does not do much argument checking by default, as thorough
1362	argument checking is very costly. Setting this variable to a true value	1577	argument checking is very costly. Setting this variable to a true value
1363	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1578	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1364	check the arguments passed to most method calls. If it finds any problems	1579	check the arguments passed to most method calls. If it finds any problems,
1365	it will croak.	1580	it will croak.
1366		1581
1367	In other words, enables "strict" mode.	1582	In other words, enables "strict" mode.
1368		1583
1369	Unlike C<use strict>, it is definitely recommended ot keep it off in	1584	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1370	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1585	>>, it is definitely recommended to keep it off in production. Keeping
1371	developing programs can be very useful, however.	1586	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1587	can be very useful, however.
1372		1588
1373	=item C<PERL_ANYEVENT_MODEL>	1589	=item C<PERL_ANYEVENT_MODEL>
1374		1590
1375	This can be used to specify the event model to be used by AnyEvent, before	1591	This can be used to specify the event model to be used by AnyEvent, before
1376	auto detection and -probing kicks in. It must be a string consisting	1592	auto detection and -probing kicks in. It must be a string consisting
…		…
1419		1635
1420	=item C<PERL_ANYEVENT_MAX_FORKS>	1636	=item C<PERL_ANYEVENT_MAX_FORKS>
1421		1637
1422	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1638	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1423	will create in parallel.	1639	will create in parallel.
		1640
		1641	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1642
		1643	The default value for the C<max_outstanding> parameter for the default DNS
		1644	resolver - this is the maximum number of parallel DNS requests that are
		1645	sent to the DNS server.
		1646
		1647	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1648
		1649	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1650	configuration) in the default resolver. When set to the empty string, no
		1651	default config will be used.
		1652
		1653	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1654
		1655	When neither C<ca_file> nor C<ca_path> was specified during
		1656	L<AnyEvent::TLS> context creation, and either of these environment
		1657	variables exist, they will be used to specify CA certificate locations
		1658	instead of a system-dependent default.
		1659
		1660	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1661
		1662	When these are set to C<1>, then the respective modules are not
		1663	loaded. Mostly good for testing AnyEvent itself.
1424		1664
1425	=back	1665	=back
1426		1666
1427	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1667	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1428		1668
…		…
1673	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	1913	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1674	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	1914	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1675	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	1915	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1676	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	1916	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1677	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	1917	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		1918	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		1919	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1678	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	1920	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1679	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	1921	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1680	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	1922	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1681	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	1923	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1682		1924
…		…
1711	performance becomes really bad with lots of file descriptors (and few of	1953	performance becomes really bad with lots of file descriptors (and few of
1712	them active), of course, but this was not subject of this benchmark.	1954	them active), of course, but this was not subject of this benchmark.
1713		1955
1714	The C<Event> module has a relatively high setup and callback invocation	1956	The C<Event> module has a relatively high setup and callback invocation
1715	cost, but overall scores in on the third place.	1957	cost, but overall scores in on the third place.
		1958
		1959	C<IO::Async> performs admirably well, about on par with C<Event>, even
		1960	when using its pure perl backend.
1716		1961
1717	C<Glib>'s memory usage is quite a bit higher, but it features a	1962	C<Glib>'s memory usage is quite a bit higher, but it features a
1718	faster callback invocation and overall ends up in the same class as	1963	faster callback invocation and overall ends up in the same class as
1719	C<Event>. However, Glib scales extremely badly, doubling the number of	1964	C<Event>. However, Glib scales extremely badly, doubling the number of
1720	watchers increases the processing time by more than a factor of four,	1965	watchers increases the processing time by more than a factor of four,
…		…
1798	it to another server. This includes deleting the old timeout and creating	2043	it to another server. This includes deleting the old timeout and creating
1799	a new one that moves the timeout into the future.	2044	a new one that moves the timeout into the future.
1800		2045
1801	=head3 Results	2046	=head3 Results
1802		2047
1803	name sockets create request	2048	name sockets create request
1804	EV 20000 69.01 11.16	2049	EV 20000 69.01 11.16
1805	Perl 20000 73.32 35.87	2050	Perl 20000 73.32 35.87
		2051	IOAsync 20000 157.00 98.14 epoll
		2052	IOAsync 20000 159.31 616.06 poll
1806	Event 20000 212.62 257.32	2053	Event 20000 212.62 257.32
1807	Glib 20000 651.16 1896.30	2054	Glib 20000 651.16 1896.30
1808	POE 20000 349.67 12317.24 uses POE::Loop::Event	2055	POE 20000 349.67 12317.24 uses POE::Loop::Event
1809		2056
1810	=head3 Discussion	2057	=head3 Discussion
1811		2058
1812	This benchmark I<does> measure scalability and overall performance of the	2059	This benchmark I<does> measure scalability and overall performance of the
1813	particular event loop.	2060	particular event loop.
…		…
1815	EV is again fastest. Since it is using epoll on my system, the setup time	2062	EV is again fastest. Since it is using epoll on my system, the setup time
1816	is relatively high, though.	2063	is relatively high, though.
1817		2064
1818	Perl surprisingly comes second. It is much faster than the C-based event	2065	Perl surprisingly comes second. It is much faster than the C-based event
1819	loops Event and Glib.	2066	loops Event and Glib.
		2067
		2068	IO::Async performs very well when using its epoll backend, and still quite
		2069	good compared to Glib when using its pure perl backend.
1820		2070
1821	Event suffers from high setup time as well (look at its code and you will	2071	Event suffers from high setup time as well (look at its code and you will
1822	understand why). Callback invocation also has a high overhead compared to	2072	understand why). Callback invocation also has a high overhead compared to
1823	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2073	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1824	uses select or poll in basically all documented configurations.	2074	uses select or poll in basically all documented configurations.
…		…
1887	=item * C-based event loops perform very well with small number of	2137	=item * C-based event loops perform very well with small number of
1888	watchers, as the management overhead dominates.	2138	watchers, as the management overhead dominates.
1889		2139
1890	=back	2140	=back
1891		2141
		2142	=head2 THE IO::Lambda BENCHMARK
		2143
		2144	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2145	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2146	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2147	shouldn't come as a surprise to anybody). As such, the benchmark is
		2148	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2149	very optimal. But how would AnyEvent compare when used without the extra
		2150	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2151
		2152	The benchmark itself creates an echo-server, and then, for 500 times,
		2153	connects to the echo server, sends a line, waits for the reply, and then
		2154	creates the next connection. This is a rather bad benchmark, as it doesn't
		2155	test the efficiency of the framework or much non-blocking I/O, but it is a
		2156	benchmark nevertheless.
		2157
		2158	name runtime
		2159	Lambda/select 0.330 sec
		2160	+ optimized 0.122 sec
		2161	Lambda/AnyEvent 0.327 sec
		2162	+ optimized 0.138 sec
		2163	Raw sockets/select 0.077 sec
		2164	POE/select, components 0.662 sec
		2165	POE/select, raw sockets 0.226 sec
		2166	POE/select, optimized 0.404 sec
		2167
		2168	AnyEvent/select/nb 0.085 sec
		2169	AnyEvent/EV/nb 0.068 sec
		2170	+state machine 0.134 sec
		2171
		2172	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2173	benchmarks actually make blocking connects and use 100% blocking I/O,
		2174	defeating the purpose of an event-based solution. All of the newly
		2175	written AnyEvent benchmarks use 100% non-blocking connects (using
		2176	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2177	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2178	generally require a lot more bookkeeping and event handling than blocking
		2179	connects (which involve a single syscall only).
		2180
		2181	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2182	offers similar expressive power as POE and IO::Lambda, using conventional
		2183	Perl syntax. This means that both the echo server and the client are 100%
		2184	non-blocking, further placing it at a disadvantage.
		2185
		2186	As you can see, the AnyEvent + EV combination even beats the
		2187	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2188	backend easily beats IO::Lambda and POE.
		2189
		2190	And even the 100% non-blocking version written using the high-level (and
		2191	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2192	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2193	in a non-blocking way.
		2194
		2195	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2196	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2197	part of the IO::lambda distribution and were used without any changes.
		2198
1892		2199
1893	=head1 SIGNALS	2200	=head1 SIGNALS
1894		2201
1895	AnyEvent currently installs handlers for these signals:	2202	AnyEvent currently installs handlers for these signals:
1896		2203
…		…
1899	=item SIGCHLD	2206	=item SIGCHLD
1900		2207
1901	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2208	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1902	emulation for event loops that do not support them natively. Also, some	2209	emulation for event loops that do not support them natively. Also, some
1903	event loops install a similar handler.	2210	event loops install a similar handler.
		2211
		2212	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2213	AnyEvent will reset it to default, to avoid losing child exit statuses.
1904		2214
1905	=item SIGPIPE	2215	=item SIGPIPE
1906		2216
1907	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2217	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1908	when AnyEvent gets loaded.	2218	when AnyEvent gets loaded.
…		…
1920		2230
1921	=back	2231	=back
1922		2232
1923	=cut	2233	=cut
1924		2234
		2235	undef $SIG{CHLD}
		2236	if $SIG{CHLD} eq 'IGNORE';
		2237
1925	$SIG{PIPE} = sub { }	2238	$SIG{PIPE} = sub { }
1926	unless defined $SIG{PIPE};	2239	unless defined $SIG{PIPE};
		2240
		2241	=head1 RECOMMENDED/OPTIONAL MODULES
		2242
		2243	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2244	it's built-in modules) are required to use it.
		2245
		2246	That does not mean that AnyEvent won't take advantage of some additional
		2247	modules if they are installed.
		2248
		2249	This section epxlains which additional modules will be used, and how they
		2250	affect AnyEvent's operetion.
		2251
		2252	=over 4
		2253
		2254	=item L<Async::Interrupt>
		2255
		2256	This slightly arcane module is used to implement fast signal handling: To
		2257	my knowledge, there is no way to do completely race-free and quick
		2258	signal handling in pure perl. To ensure that signals still get
		2259	delivered, AnyEvent will start an interval timer to wake up perl (and
		2260	catch the signals) with soemd elay (default is 10 seconds, look for
		2261	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2262
		2263	If this module is available, then it will be used to implement signal
		2264	catching, which means that signals will not be delayed, and the event loop
		2265	will not be interrupted regularly, which is more efficient (And good for
		2266	battery life on laptops).
		2267
		2268	This affects not just the pure-perl event loop, but also other event loops
		2269	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2270
		2271	=item L<EV>
		2272
		2273	This module isn't really "optional", as it is simply one of the backend
		2274	event loops that AnyEvent can use. However, it is simply the best event
		2275	loop available in terms of features, speed and stability: It supports
		2276	the AnyEvent API optimally, implements all the watcher types in XS, does
		2277	automatic timer adjustments even when no monotonic clock is available,
		2278	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2279	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2280	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2281
		2282	=item L<Guard>
		2283
		2284	The guard module, when used, will be used to implement
		2285	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2286	lot less memory), but otherwise doesn't affect guard operation much. It is
		2287	purely used for performance.
		2288
		2289	=item L<JSON> and L<JSON::XS>
		2290
		2291	This module is required when you want to read or write JSON data via
		2292	L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2293	advantage of the ulta-high-speed L<JSON::XS> module when it is installed.
		2294
		2295	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2296	installed.
		2297
		2298	=item L<Net::SSLeay>
		2299
		2300	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2301	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2302	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2303
		2304	=item L<Time::HiRes>
		2305
		2306	This module is part of perl since release 5.008. It will be used when the
		2307	chosen event library does not come with a timing source on it's own. The
		2308	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2309	try to use a monotonic clock for timing stability.
		2310
		2311	=back
1927		2312
1928		2313
1929	=head1 FORK	2314	=head1 FORK
1930		2315
1931	Most event libraries are not fork-safe. The ones who are usually are	2316	Most event libraries are not fork-safe. The ones who are usually are
1932	because they rely on inefficient but fork-safe C<select> or C<poll>	2317	because they rely on inefficient but fork-safe C<select> or C<poll>
1933	calls. Only L<EV> is fully fork-aware.	2318	calls. Only L<EV> is fully fork-aware.
1934		2319
1935	If you have to fork, you must either do so I<before> creating your first	2320	If you have to fork, you must either do so I<before> creating your first
1936	watcher OR you must not use AnyEvent at all in the child.	2321	watcher OR you must not use AnyEvent at all in the child OR you must do
		2322	something completely out of the scope of AnyEvent.
1937		2323
1938		2324
1939	=head1 SECURITY CONSIDERATIONS	2325	=head1 SECURITY CONSIDERATIONS
1940		2326
1941	AnyEvent can be forced to load any event model via	2327	AnyEvent can be forced to load any event model via
…		…
1953	use AnyEvent;	2339	use AnyEvent;
1954		2340
1955	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2341	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1956	be used to probe what backend is used and gain other information (which is	2342	be used to probe what backend is used and gain other information (which is
1957	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2343	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1958	$ENV{PERL_ANYEGENT_STRICT}.	2344	$ENV{PERL_ANYEVENT_STRICT}.
		2345
		2346	Note that AnyEvent will remove I<all> environment variables starting with
		2347	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2348	enabled.
1959		2349
1960		2350
1961	=head1 BUGS	2351	=head1 BUGS
1962		2352
1963	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2353	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
…		…
1975	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2365	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1976		2366
1977	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2367	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1978	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2368	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1979	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2369	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1980	L<AnyEvent::Impl::POE>.	2370	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.
1981		2371
1982	Non-blocking file handles, sockets, TCP clients and	2372	Non-blocking file handles, sockets, TCP clients and
1983	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2373	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1984		2374
1985	Asynchronous DNS: L<AnyEvent::DNS>.	2375	Asynchronous DNS: L<AnyEvent::DNS>.
1986		2376
1987	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2377	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2378	L<Coro::Event>,
1988		2379
1989	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2380	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2381	L<AnyEvent::HTTP>.
1990		2382
1991		2383
1992	=head1 AUTHOR	2384	=head1 AUTHOR
1993		2385
1994	Marc Lehmann <schmorp@schmorp.de>	2386	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.212 by root, Sun Jun 7 16:48:38 2009 UTC vs. Revision 1.244 by root, Fri Jul 17 23:15:57 2009 UTC

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Revision 1.212 by root, Sun Jun 7 16:48:38 2009 UTC vs.
Revision 1.244 by root, Fri Jul 17 23:15:57 2009 UTC