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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.217 by root, Tue Jun 23 23:37:32 2009 UTC vs.
Revision 1.259 by root, Tue Jul 28 02:07:18 2009 UTC

…		…
1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
6	event loops.	6	and POE are various supported event loops/environments.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
40	=head1 INTRODUCTION/TUTORIAL	40	=head1 INTRODUCTION/TUTORIAL
41		41
42	This manpage is mainly a reference manual. If you are interested	42	This manpage is mainly a reference manual. If you are interested
43	in a tutorial or some gentle introduction, have a look at the	43	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	44	L<AnyEvent::Intro> manpage.
		45
		46	=head1 SUPPORT
		47
		48	There is a mailinglist for discussing all things AnyEvent, and an IRC
		49	channel, too.
		50
		51	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		52	Repository>, at L<http://anyevent.schmorp.de>, for more info.
45		53
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	54	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		55
48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	56	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49	nowadays. So what is different about AnyEvent?	57	nowadays. So what is different about AnyEvent?
…		…
176	=head2 I/O WATCHERS	184	=head2 I/O WATCHERS
177		185
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	186	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	187	with the following mandatory key-value pairs as arguments:
180		188
181	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch	189	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	190	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	191	handle). Note that only file handles pointing to things for which
184	non-blocking operation makes sense are allowed. This includes sockets,	192	non-blocking operation makes sense are allowed. This includes sockets,
185	most character devices, pipes, fifos and so on, but not for example files	193	most character devices, pipes, fifos and so on, but not for example files
186	or block devices.	194	or block devices.
…		…
361	invocation, and callback invocation will be synchronous. Synchronous means	369	invocation, and callback invocation will be synchronous. Synchronous means
362	that it might take a while until the signal gets handled by the process,	370	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.	371	but it is guaranteed not to interrupt any other callbacks.
364		372
365	The main advantage of using these watchers is that you can share a signal	373	The main advantage of using these watchers is that you can share a signal
366	between multiple watchers.	374	between multiple watchers, and AnyEvent will ensure that signals will not
		375	interrupt your program at bad times.
367		376
368	This watcher might use C<%SIG>, so programs overwriting those signals	377	This watcher might use C<%SIG> (depending on the event loop used),
369	directly will likely not work correctly.	378	so programs overwriting those signals directly will likely not work
		379	correctly.
370		380
371	Example: exit on SIGINT	381	Example: exit on SIGINT
372		382
373	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	383	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
374		384
		385	=head3 Signal Races, Delays and Workarounds
		386
		387	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		388	callbacks to signals in a generic way, which is a pity, as you cannot do
		389	race-free signal handling in perl. AnyEvent will try to do it's best, but
		390	in some cases, signals will be delayed. The maximum time a signal might
		391	be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10
		392	seconds). This variable can be changed only before the first signal
		393	watcher is created, and should be left alone otherwise. Higher values
		394	will cause fewer spurious wake-ups, which is better for power and CPU
		395	saving. All these problems can be avoided by installing the optional
		396	L<Async::Interrupt> module. This will not work with inherently broken
		397	event loops such as L<Event> or L<Event::Lib> (and not with L<POE>
		398	currently, as POE does it's own workaround with one-second latency). With
		399	those, you just have to suffer the delays.
		400
375	=head2 CHILD PROCESS WATCHERS	401	=head2 CHILD PROCESS WATCHERS
376		402
377	You can also watch on a child process exit and catch its exit status.	403	You can also watch on a child process exit and catch its exit status.
378		404
379	The child process is specified by the C<pid> argument (if set to C<0>, it	405	The child process is specified by the C<pid> argument (one some backends,
380	watches for any child process exit). The watcher will triggered only when	406	using C<0> watches for any child process exit, on others this will
381	the child process has finished and an exit status is available, not on	407	croak). The watcher will be triggered only when the child process has
382	any trace events (stopped/continued).	408	finished and an exit status is available, not on any trace events
		409	(stopped/continued).
383		410
384	The callback will be called with the pid and exit status (as returned by	411	The callback will be called with the pid and exit status (as returned by
385	waitpid), so unlike other watcher types, you I<can> rely on child watcher	412	waitpid), so unlike other watcher types, you I<can> rely on child watcher
386	callback arguments.	413	callback arguments.
387		414
…		…
392		419
393	There is a slight catch to child watchers, however: you usually start them	420	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	421	I<after> the child process was created, and this means the process could
395	have exited already (and no SIGCHLD will be sent anymore).	422	have exited already (and no SIGCHLD will be sent anymore).
396		423
397	Not all event models handle this correctly (POE doesn't), but even for	424	Not all event models handle this correctly (neither POE nor IO::Async do,
		425	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	426	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).	427	the process exits (i.e. before you fork in the first place). AnyEvent's
		428	pure perl event loop handles all cases correctly regardless of when you
		429	start the watcher.
400		430
401	This means you cannot create a child watcher as the very first thing in an	431	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	432	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>).	433	watcher before you C<fork> the child (alternatively, you can call
		434	C<AnyEvent::detect>).
		435
		436	As most event loops do not support waiting for child events, they will be
		437	emulated by AnyEvent in most cases, in which the latency and race problems
		438	mentioned in the description of signal watchers apply.
404		439
405	Example: fork a process and wait for it	440	Example: fork a process and wait for it
406		441
407	my $done = AnyEvent->condvar;	442	my $done = AnyEvent->condvar;
408		443
…		…
459		494
460	If you are familiar with some event loops you will know that all of them	495	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	496	require you to run some blocking "loop", "run" or similar function that
462	will actively watch for new events and call your callbacks.	497	will actively watch for new events and call your callbacks.
463		498
464	AnyEvent is different, it expects somebody else to run the event loop and	499	AnyEvent is slightly different: it expects somebody else to run the event
465	will only block when necessary (usually when told by the user).	500	loop and will only block when necessary (usually when told by the user).
466		501
467	The instrument to do that is called a "condition variable", so called	502	The instrument to do that is called a "condition variable", so called
468	because they represent a condition that must become true.	503	because they represent a condition that must become true.
469		504
		505	Now is probably a good time to look at the examples further below.
		506
470	Condition variables can be created by calling the C<< AnyEvent->condvar	507	Condition variables can be created by calling the C<< AnyEvent->condvar
471	>> method, usually without arguments. The only argument pair allowed is	508	>> 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	509	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	510	becomes true, with the condition variable as the first argument (but not
475	the results).	511	the results).
476		512
477	After creation, the condition variable is "false" until it becomes "true"	513	After creation, the condition variable is "false" until it becomes "true"
…		…
482	Condition variables are similar to callbacks, except that you can	518	Condition variables are similar to callbacks, except that you can
483	optionally wait for them. They can also be called merge points - points	519	optionally wait for them. They can also be called merge points - points
484	in time where multiple outstanding events have been processed. And yet	520	in time where multiple outstanding events have been processed. And yet
485	another way to call them is transactions - each condition variable can be	521	another way to call them is transactions - each condition variable can be
486	used to represent a transaction, which finishes at some point and delivers	522	used to represent a transaction, which finishes at some point and delivers
487	a result.	523	a result. And yet some people know them as "futures" - a promise to
		524	compute/deliver something that you can wait for.
488		525
489	Condition variables are very useful to signal that something has finished,	526	Condition variables are very useful to signal that something has finished,
490	for example, if you write a module that does asynchronous http requests,	527	for example, if you write a module that does asynchronous http requests,
491	then a condition variable would be the ideal candidate to signal the	528	then a condition variable would be the ideal candidate to signal the
492	availability of results. The user can either act when the callback is	529	availability of results. The user can either act when the callback is
…		…
526	after => 1,	563	after => 1,
527	cb => sub { $result_ready->send },	564	cb => sub { $result_ready->send },
528	);	565	);
529		566
530	# this "blocks" (while handling events) till the callback	567	# this "blocks" (while handling events) till the callback
531	# calls send	568	# calls -<send
532	$result_ready->recv;	569	$result_ready->recv;
533		570
534	Example: wait for a timer, but take advantage of the fact that	571	Example: wait for a timer, but take advantage of the fact that condition
535	condition variables are also code references.	572	variables are also callable directly.
536		573
537	my $done = AnyEvent->condvar;	574	my $done = AnyEvent->condvar;
538	my $delay = AnyEvent->timer (after => 5, cb => $done);	575	my $delay = AnyEvent->timer (after => 5, cb => $done);
539	$done->recv;	576	$done->recv;
540		577
…		…
546		583
547	...	584	...
548		585
549	my @info = $couchdb->info->recv;	586	my @info = $couchdb->info->recv;
550		587
551	And this is how you would just ste a callback to be called whenever the	588	And this is how you would just set a callback to be called whenever the
552	results are available:	589	results are available:
553		590
554	$couchdb->info->cb (sub {	591	$couchdb->info->cb (sub {
555	my @info = $_[0]->recv;	592	my @info = $_[0]->recv;
556	});	593	});
…		…
574	immediately from within send.	611	immediately from within send.
575		612
576	Any arguments passed to the C<send> call will be returned by all	613	Any arguments passed to the C<send> call will be returned by all
577	future C<< ->recv >> calls.	614	future C<< ->recv >> calls.
578		615
579	Condition variables are overloaded so one can call them directly	616	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	617	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	618	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		619
588	=item $cv->croak ($error)	620	=item $cv->croak ($error)
589		621
590	Similar to send, but causes all call's to C<< ->recv >> to invoke	622	Similar to send, but causes all call's to C<< ->recv >> to invoke
591	C<Carp::croak> with the given error message/object/scalar.	623	C<Carp::croak> with the given error message/object/scalar.
592		624
593	This can be used to signal any errors to the condition variable	625	This can be used to signal any errors to the condition variable
594	user/consumer.	626	user/consumer. Doing it this way instead of calling C<croak> directly
		627	delays the error detetcion, but has the overwhelmign advantage that it
		628	diagnoses the error at the place where the result is expected, and not
		629	deep in some event clalback without connection to the actual code causing
		630	the problem.
595		631
596	=item $cv->begin ([group callback])	632	=item $cv->begin ([group callback])
597		633
598	=item $cv->end	634	=item $cv->end
599
600	These two methods are EXPERIMENTAL and MIGHT CHANGE.
601		635
602	These two methods can be used to combine many transactions/events into	636	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	637	one. For example, a function that pings many hosts in parallel might want
604	to use a condition variable for the whole process.	638	to use a condition variable for the whole process.
605		639
…		…
607	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	641	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	642	>>, 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	643	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.	644	callback was set, C<send> will be called without any arguments.
611		645
612	Let's clarify this with the ping example:	646	You can think of C<< $cv->send >> giving you an OR condition (one call
		647	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		648	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		649
		650	Let's start with a simple example: you have two I/O watchers (for example,
		651	STDOUT and STDERR for a program), and you want to wait for both streams to
		652	close before activating a condvar:
		653
		654	my $cv = AnyEvent->condvar;
		655
		656	$cv->begin; # first watcher
		657	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		658	defined sysread $fh1, my $buf, 4096
		659	or $cv->end;
		660	});
		661
		662	$cv->begin; # second watcher
		663	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		664	defined sysread $fh2, my $buf, 4096
		665	or $cv->end;
		666	});
		667
		668	$cv->recv;
		669
		670	This works because for every event source (EOF on file handle), there is
		671	one call to C<begin>, so the condvar waits for all calls to C<end> before
		672	sending.
		673
		674	The ping example mentioned above is slightly more complicated, as the
		675	there are results to be passwd back, and the number of tasks that are
		676	begung can potentially be zero:
613		677
614	my $cv = AnyEvent->condvar;	678	my $cv = AnyEvent->condvar;
615		679
616	my %result;	680	my %result;
617	$cv->begin (sub { $cv->send (\%result) });	681	$cv->begin (sub { $cv->send (\%result) });
…		…
637	loop, which serves two important purposes: first, it sets the callback	701	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	702	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	703	C<send> is called even when C<no> hosts are being pinged (the loop
640	doesn't execute once).	704	doesn't execute once).
641		705
642	This is the general pattern when you "fan out" into multiple subrequests:	706	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>	707	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	708	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>.	709	subrequest you start, call C<begin> and for each subrequest you finish,
		710	call C<end>.
646		711
647	=back	712	=back
648		713
649	=head3 METHODS FOR CONSUMERS	714	=head3 METHODS FOR CONSUMERS
650		715
…		…
666	function will call C<croak>.	731	function will call C<croak>.
667		732
668	In list context, all parameters passed to C<send> will be returned,	733	In list context, all parameters passed to C<send> will be returned,
669	in scalar context only the first one will be returned.	734	in scalar context only the first one will be returned.
670		735
		736	Note that doing a blocking wait in a callback is not supported by any
		737	event loop, that is, recursive invocation of a blocking C<< ->recv
		738	>> is not allowed, and the C<recv> call will C<croak> if such a
		739	condition is detected. This condition can be slightly loosened by using
		740	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		741	any thread that doesn't run the event loop itself.
		742
671	Not all event models support a blocking wait - some die in that case	743	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	744	(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	745	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	746	caller decide whether the call will block or not (for example, by coupling
675	condition variables with some kind of request results and supporting	747	condition variables with some kind of request results and supporting
676	callbacks so the caller knows that getting the result will not block,	748	callbacks so the caller knows that getting the result will not block,
677	while still supporting blocking waits if the caller so desires).	749	while still supporting blocking waits if the caller so desires).
678		750
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	751	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	752	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	753	time). This will work even when the event loop does not support blocking
693	waits otherwise.	754	waits otherwise.
694		755
…		…
707	variable itself. Calling C<recv> inside the callback or at any later time	768	variable itself. Calling C<recv> inside the callback or at any later time
708	is guaranteed not to block.	769	is guaranteed not to block.
709		770
710	=back	771	=back
711		772
		773	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		774
		775	The available backend classes are (every class has its own manpage):
		776
		777	=over 4
		778
		779	=item Backends that are autoprobed when no other event loop can be found.
		780
		781	EV is the preferred backend when no other event loop seems to be in
		782	use. If EV is not installed, then AnyEvent will try Event, and, failing
		783	that, will fall back to its own pure-perl implementation, which is
		784	available everywhere as it comes with AnyEvent itself.
		785
		786	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		787	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		788	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		789
		790	=item Backends that are transparently being picked up when they are used.
		791
		792	These will be used when they are currently loaded when the first watcher
		793	is created, in which case it is assumed that the application is using
		794	them. This means that AnyEvent will automatically pick the right backend
		795	when the main program loads an event module before anything starts to
		796	create watchers. Nothing special needs to be done by the main program.
		797
		798	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		799	AnyEvent::Impl::Tk based on Tk, very broken.
		800	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		801	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		802	AnyEvent::Impl::Irssi used when running within irssi.
		803
		804	=item Backends with special needs.
		805
		806	Qt requires the Qt::Application to be instantiated first, but will
		807	otherwise be picked up automatically. As long as the main program
		808	instantiates the application before any AnyEvent watchers are created,
		809	everything should just work.
		810
		811	AnyEvent::Impl::Qt based on Qt.
		812
		813	Support for IO::Async can only be partial, as it is too broken and
		814	architecturally limited to even support the AnyEvent API. It also
		815	is the only event loop that needs the loop to be set explicitly, so
		816	it can only be used by a main program knowing about AnyEvent. See
		817	L<AnyEvent::Impl::Async> for the gory details.
		818
		819	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		820
		821	=item Event loops that are indirectly supported via other backends.
		822
		823	Some event loops can be supported via other modules:
		824
		825	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		826
		827	B<WxWidgets> has no support for watching file handles. However, you can
		828	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		829	polls 20 times per second, which was considered to be too horrible to even
		830	consider for AnyEvent.
		831
		832	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		833	backend, so it can be supported through POE.
		834
		835	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		836	load L<POE> when detecting them, in the hope that POE will pick them up,
		837	in which case everything will be automatic.
		838
		839	=back
		840
712	=head1 GLOBAL VARIABLES AND FUNCTIONS	841	=head1 GLOBAL VARIABLES AND FUNCTIONS
713		842
		843	These are not normally required to use AnyEvent, but can be useful to
		844	write AnyEvent extension modules.
		845
714	=over 4	846	=over 4
715		847
716	=item $AnyEvent::MODEL	848	=item $AnyEvent::MODEL
717		849
718	Contains C<undef> until the first watcher is being created. Then it	850	Contains C<undef> until the first watcher is being created, before the
		851	backend has been autodetected.
		852
719	contains the event model that is being used, which is the name of the	853	Afterwards it contains the event model that is being used, which is the
720	Perl class implementing the model. This class is usually one of the	854	name of the Perl class implementing the model. This class is usually one
721	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	855	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
722	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	856	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
723		857	will be C<urxvt::anyevent>).
724	The known classes so far are:
725
726	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
727	AnyEvent::Impl::Event based on Event, second best choice.
728	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
729	AnyEvent::Impl::Glib based on Glib, third-best choice.
730	AnyEvent::Impl::Tk based on Tk, very bad choice.
731	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
732	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
733	AnyEvent::Impl::POE based on POE, not generic enough for full support.
734
735	There is no support for WxWidgets, as WxWidgets has no support for
736	watching file handles. However, you can use WxWidgets through the
737	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
738	second, which was considered to be too horrible to even consider for
739	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
740	it's adaptor.
741
742	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
743	autodetecting them.
744		858
745	=item AnyEvent::detect	859	=item AnyEvent::detect
746		860
747	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	861	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
748	if necessary. You should only call this function right before you would	862	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	863	have created an AnyEvent watcher anyway, that is, as late as possible at
750	runtime.	864	runtime, and not e.g. while initialising of your module.
		865
		866	If you need to do some initialisation before AnyEvent watchers are
		867	created, use C<post_detect>.
751		868
752	=item $guard = AnyEvent::post_detect { BLOCK }	869	=item $guard = AnyEvent::post_detect { BLOCK }
753		870
754	Arranges for the code block to be executed as soon as the event model is	871	Arranges for the code block to be executed as soon as the event model is
755	autodetected (or immediately if this has already happened).	872	autodetected (or immediately if this has already happened).
756		873
		874	The block will be executed I<after> the actual backend has been detected
		875	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		876	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		877	other initialisations - see the sources of L<AnyEvent::Strict> or
		878	L<AnyEvent::AIO> to see how this is used.
		879
		880	The most common usage is to create some global watchers, without forcing
		881	event module detection too early, for example, L<AnyEvent::AIO> creates
		882	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		883	avoid autodetecting the event module at load time.
		884
757	If called in scalar or list context, then it creates and returns an object	885	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	886	that automatically removes the callback again when it is destroyed (or
		887	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
759	L<Coro::BDB> for a case where this is useful.	888	a case where this is useful.
		889
		890	Example: Create a watcher for the IO::AIO module and store it in
		891	C<$WATCHER>. Only do so after the event loop is initialised, though.
		892
		893	our WATCHER;
		894
		895	my $guard = AnyEvent::post_detect {
		896	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		897	};
		898
		899	# the \|\|= is important in case post_detect immediately runs the block,
		900	# as to not clobber the newly-created watcher. assigning both watcher and
		901	# post_detect guard to the same variable has the advantage of users being
		902	# able to just C<undef $WATCHER> if the watcher causes them grief.
		903
		904	$WATCHER \|\|= $guard;
760		905
761	=item @AnyEvent::post_detect	906	=item @AnyEvent::post_detect
762		907
763	If there are any code references in this array (you can C<push> to it	908	If there are any code references in this array (you can C<push> to it
764	before or after loading AnyEvent), then they will called directly after	909	before or after loading AnyEvent), then they will called directly after
765	the event loop has been chosen.	910	the event loop has been chosen.
766		911
767	You should check C<$AnyEvent::MODEL> before adding to this array, though:	912	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,	913	if it is defined then the event loop has already been detected, and the
769	and the array will be ignored.	914	array will be ignored.
770		915
771	Best use C<AnyEvent::post_detect { BLOCK }> instead.	916	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		917	it,as it takes care of these details.
		918
		919	This variable is mainly useful for modules that can do something useful
		920	when AnyEvent is used and thus want to know when it is initialised, but do
		921	not need to even load it by default. This array provides the means to hook
		922	into AnyEvent passively, without loading it.
772		923
773	=back	924	=back
774		925
775	=head1 WHAT TO DO IN A MODULE	926	=head1 WHAT TO DO IN A MODULE
776		927
…		…
831		982
832		983
833	=head1 OTHER MODULES	984	=head1 OTHER MODULES
834		985
835	The following is a non-exhaustive list of additional modules that use	986	The following is a non-exhaustive list of additional modules that use
836	AnyEvent and can therefore be mixed easily with other AnyEvent modules	987	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	988	modules and other event loops in the same program. Some of the modules
838	available via CPAN.	989	come with AnyEvent, most are available via CPAN.
839		990
840	=over 4	991	=over 4
841		992
842	=item L<AnyEvent::Util>	993	=item L<AnyEvent::Util>
843		994
…		…
852		1003
853	=item L<AnyEvent::Handle>	1004	=item L<AnyEvent::Handle>
854		1005
855	Provide read and write buffers, manages watchers for reads and writes,	1006	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	1007	supports raw and formatted I/O, I/O queued and fully transparent and
857	non-blocking SSL/TLS.	1008	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
858		1009
859	=item L<AnyEvent::DNS>	1010	=item L<AnyEvent::DNS>
860		1011
861	Provides rich asynchronous DNS resolver capabilities.	1012	Provides rich asynchronous DNS resolver capabilities.
862		1013
…		…
890		1041
891	=item L<AnyEvent::GPSD>	1042	=item L<AnyEvent::GPSD>
892		1043
893	A non-blocking interface to gpsd, a daemon delivering GPS information.	1044	A non-blocking interface to gpsd, a daemon delivering GPS information.
894		1045
		1046	=item L<AnyEvent::IRC>
		1047
		1048	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1049
		1050	=item L<AnyEvent::XMPP>
		1051
		1052	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1053	Net::XMPP2>.
		1054
895	=item L<AnyEvent::IGS>	1055	=item L<AnyEvent::IGS>
896		1056
897	A non-blocking interface to the Internet Go Server protocol (used by	1057	A non-blocking interface to the Internet Go Server protocol (used by
898	L<App::IGS>).	1058	L<App::IGS>).
899		1059
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>	1060	=item L<Net::FCP>
909		1061
910	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1062	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
911	of AnyEvent.	1063	of AnyEvent.
912		1064
…		…
916		1068
917	=item L<Coro>	1069	=item L<Coro>
918		1070
919	Has special support for AnyEvent via L<Coro::AnyEvent>.	1071	Has special support for AnyEvent via L<Coro::AnyEvent>.
920		1072
921	=item L<IO::Lambda>
922
923	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
924
925	=back	1073	=back
926		1074
927	=cut	1075	=cut
928		1076
929	package AnyEvent;	1077	package AnyEvent;
930		1078
		1079	# basically a tuned-down version of common::sense
		1080	sub common_sense {
931	no warnings;	1081	# no warnings
		1082	${^WARNING_BITS} ^= ${^WARNING_BITS};
932	use strict qw(vars subs);	1083	# use strict vars subs
		1084	$^H \|= 0x00000600;
		1085	}
933		1086
		1087	BEGIN { AnyEvent::common_sense }
		1088
934	use Carp;	1089	use Carp ();
935		1090
936	our $VERSION = 4.412;	1091	our $VERSION = 4.88;
937	our $MODEL;	1092	our $MODEL;
938		1093
939	our $AUTOLOAD;	1094	our $AUTOLOAD;
940	our @ISA;	1095	our @ISA;
941		1096
942	our @REGISTRY;	1097	our @REGISTRY;
943		1098
944	our $WIN32;	1099	our $WIN32;
		1100
		1101	our $VERBOSE;
945		1102
946	BEGIN {	1103	BEGIN {
947	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1104	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
948	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1105	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
949		1106
950	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1107	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
951	if ${^TAINT};	1108	if ${^TAINT};
952	}
953		1109
954	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1110	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1111
		1112	}
		1113
		1114	our $MAX_SIGNAL_LATENCY = 10;
955		1115
956	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred	1116	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
957		1117
958	{	1118	{
959	my $idx;	1119	my $idx;
…		…
961	for reverse split /\s,\s/,	1121	for reverse split /\s,\s/,
962	$ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";	1122	$ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
963	}	1123	}
964		1124
965	my @models = (	1125	my @models = (
966	[EV:: => AnyEvent::Impl::EV::],	1126	[EV:: => AnyEvent::Impl::EV:: , 1],
967	[Event:: => AnyEvent::Impl::Event::],	1127	[Event:: => AnyEvent::Impl::Event::, 1],
968	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1128	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
969	# everything below here will not be autoprobed	1129	# everything below here will not (normally) be autoprobed
970	# as the pureperl backend should work everywhere	1130	# as the pureperl backend should work everywhere
971	# and is usually faster	1131	# and is usually faster
		1132	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1133	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1134	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
972	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1135	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
973	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
974	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
975	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1136	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
976	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1137	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
977	[Wx:: => AnyEvent::Impl::POE::],	1138	[Wx:: => AnyEvent::Impl::POE::],
978	[Prima:: => AnyEvent::Impl::POE::],	1139	[Prima:: => AnyEvent::Impl::POE::],
		1140	# IO::Async is just too broken - we would need workarounds for its
		1141	# byzantine signal and broken child handling, among others.
		1142	# IO::Async is rather hard to detect, as it doesn't have any
		1143	# obvious default class.
		1144	# [0, IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1145	# [0, IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1146	# [0, IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
979	);	1147	);
980		1148
981	our %method = map +($_ => 1),	1149	our %method = map +($_ => 1),
982	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1150	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
983		1151
…		…
987	my ($cb) = @_;	1155	my ($cb) = @_;
988		1156
989	if ($MODEL) {	1157	if ($MODEL) {
990	$cb->();	1158	$cb->();
991		1159
992	1	1160	undef
993	} else {	1161	} else {
994	push @post_detect, $cb;	1162	push @post_detect, $cb;
995		1163
996	defined wantarray	1164	defined wantarray
997	? bless \$cb, "AnyEvent::Util::postdetect"	1165	? bless \$cb, "AnyEvent::Util::postdetect"
…		…
1003	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1171	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1004	}	1172	}
1005		1173
1006	sub detect() {	1174	sub detect() {
1007	unless ($MODEL) {	1175	unless ($MODEL) {
1008	no strict 'refs';
1009	local $SIG{__DIE__};	1176	local $SIG{__DIE__};
1010		1177
1011	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1178	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1012	my $model = "AnyEvent::Impl::$1";	1179	my $model = "AnyEvent::Impl::$1";
1013	if (eval "require $model") {	1180	if (eval "require $model") {
1014	$MODEL = $model;	1181	$MODEL = $model;
1015	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1182	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1016	} else {	1183	} else {
1017	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1184	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1018	}	1185	}
1019	}	1186	}
1020		1187
1021	# check for already loaded models	1188	# check for already loaded models
1022	unless ($MODEL) {	1189	unless ($MODEL) {
1023	for (@REGISTRY, @models) {	1190	for (@REGISTRY, @models) {
1024	my ($package, $model) = @$_;	1191	my ($package, $model) = @$_;
1025	if (${"$package\::VERSION"} > 0) {	1192	if (${"$package\::VERSION"} > 0) {
1026	if (eval "require $model") {	1193	if (eval "require $model") {
1027	$MODEL = $model;	1194	$MODEL = $model;
1028	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1195	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1029	last;	1196	last;
1030	}	1197	}
1031	}	1198	}
1032	}	1199	}
1033		1200
1034	unless ($MODEL) {	1201	unless ($MODEL) {
1035	# try to load a model	1202	# try to autoload a model
1036
1037	for (@REGISTRY, @models) {	1203	for (@REGISTRY, @models) {
1038	my ($package, $model) = @$_;	1204	my ($package, $model, $autoload) = @$_;
		1205	if (
		1206	$autoload
1039	if (eval "require $package"	1207	and eval "require $package"
1040	and ${"$package\::VERSION"} > 0	1208	and ${"$package\::VERSION"} > 0
1041	and eval "require $model") {	1209	and eval "require $model"
		1210	) {
1042	$MODEL = $model;	1211	$MODEL = $model;
1043	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1212	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1044	last;	1213	last;
1045	}	1214	}
1046	}	1215	}
1047		1216
1048	$MODEL	1217	$MODEL
…		…
1064		1233
1065	sub AUTOLOAD {	1234	sub AUTOLOAD {
1066	(my $func = $AUTOLOAD) =~ s/.*://;	1235	(my $func = $AUTOLOAD) =~ s/.*://;
1067		1236
1068	$method{$func}	1237	$method{$func}
1069	or croak "$func: not a valid method for AnyEvent objects";	1238	or Carp::croak "$func: not a valid method for AnyEvent objects";
1070		1239
1071	detect unless $MODEL;	1240	detect unless $MODEL;
1072		1241
1073	my $class = shift;	1242	my $class = shift;
1074	$class->$func (@_);	1243	$class->$func (@_);
1075	}	1244	}
1076		1245
1077	# utility function to dup a filehandle. this is used by many backends	1246	# utility function to dup a filehandle. this is used by many backends
1078	# to support binding more than one watcher per filehandle (they usually	1247	# to support binding more than one watcher per filehandle (they usually
1079	# allow only one watcher per fd, so we dup it to get a different one).	1248	# allow only one watcher per fd, so we dup it to get a different one).
1080	sub _dupfh($$$$) {	1249	sub _dupfh($$;$$) {
1081	my ($poll, $fh, $r, $w) = @_;	1250	my ($poll, $fh, $r, $w) = @_;
1082		1251
1083	# cygwin requires the fh mode to be matching, unix doesn't	1252	# cygwin requires the fh mode to be matching, unix doesn't
1084	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1253	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1085	: $poll eq "w" ? ($w, ">")
1086	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1087		1254
1088	open my $fh2, "$mode&" . fileno $fh	1255	open my $fh2, $mode, $fh
1089	or die "cannot dup() filehandle: $!,";	1256	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1090		1257
1091	# we assume CLOEXEC is already set by perl in all important cases	1258	# we assume CLOEXEC is already set by perl in all important cases
1092		1259
1093	($fh2, $rw)	1260	($fh2, $rw)
1094	}	1261	}
1095		1262
1096	package AnyEvent::Base;	1263	package AnyEvent::Base;
1097		1264
1098	# default implementations for many methods	1265	# default implementations for many methods
1099		1266
1100	BEGIN {	1267	sub _time {
		1268	# probe for availability of Time::HiRes
1101	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1269	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1270	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1102	*_time = \&Time::HiRes::time;	1271	*_time = \&Time::HiRes::time;
1103	# if (eval "use POSIX (); (POSIX::times())...	1272	# if (eval "use POSIX (); (POSIX::times())...
1104	} else {	1273	} else {
		1274	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1105	*_time = sub { time }; # epic fail	1275	*_time = sub { time }; # epic fail
1106	}	1276	}
		1277
		1278	&_time
1107	}	1279	}
1108		1280
1109	sub time { _time }	1281	sub time { _time }
1110	sub now { _time }	1282	sub now { _time }
1111	sub now_update { }	1283	sub now_update { }
…		…
1116	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1288	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1117	}	1289	}
1118		1290
1119	# default implementation for ->signal	1291	# default implementation for ->signal
1120		1292
		1293	our $HAVE_ASYNC_INTERRUPT;
1121	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1294	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1295	our (%SIG_ASY, %SIG_ASY_W);
		1296	our ($SIG_COUNT, $SIG_TW);
1122		1297
1123	sub _signal_exec {	1298	sub _signal_exec {
		1299	$HAVE_ASYNC_INTERRUPT
		1300	? $SIGPIPE_R->drain
1124	sysread $SIGPIPE_R, my $dummy, 4;	1301	: sysread $SIGPIPE_R, my $dummy, 9;
1125		1302
1126	while (%SIG_EV) {	1303	while (%SIG_EV) {
1127	for (keys %SIG_EV) {	1304	for (keys %SIG_EV) {
1128	delete $SIG_EV{$_};	1305	delete $SIG_EV{$_};
1129	$_->() for values %{ $SIG_CB{$_} \|\| {} };	1306	$_->() for values %{ $SIG_CB{$_} \|\| {} };
1130	}	1307	}
1131	}	1308	}
1132	}	1309	}
1133		1310
		1311	# install a dumym wakeupw atcher to reduce signal catching latency
		1312	sub _sig_add() {
		1313	unless ($SIG_COUNT++) {
		1314	# try to align timer on a full-second boundary, if possible
		1315	my $NOW = AnyEvent->now;
		1316
		1317	$SIG_TW = AnyEvent->timer (
		1318	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1319	interval => $MAX_SIGNAL_LATENCY,
		1320	cb => sub { }, # just for the PERL_ASYNC_CHECK
		1321	);
		1322	}
		1323	}
		1324
		1325	sub _sig_del {
		1326	undef $SIG_TW
		1327	unless --$SIG_COUNT;
		1328	}
		1329
		1330	sub _signal {
		1331	my (undef, %arg) = @_;
		1332
		1333	my $signal = uc $arg{signal}
		1334	or Carp::croak "required option 'signal' is missing";
		1335
		1336	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1337
		1338	if ($HAVE_ASYNC_INTERRUPT) {
		1339	# async::interrupt
		1340
		1341	$SIG_ASY{$signal} \|\|= do {
		1342	my $asy = new Async::Interrupt
		1343	cb => sub { undef $SIG_EV{$signal} },
		1344	signal => $signal,
		1345	pipe => [$SIGPIPE_R->filenos],
		1346	;
		1347	$asy->pipe_autodrain (0);
		1348
		1349	$asy
		1350	};
		1351
		1352	} else {
		1353	# pure perl
		1354
		1355	$SIG{$signal} \|\|= sub {
		1356	local $!;
		1357	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1358	undef $SIG_EV{$signal};
		1359	};
		1360
		1361	# can't do signal processing without introducing races in pure perl,
		1362	# so limit the signal latency.
		1363	_sig_add;
		1364	}
		1365
		1366	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1367	}
		1368
1134	sub signal {	1369	sub signal {
1135	my (undef, %arg) = @_;	1370	# probe for availability of Async::Interrupt
		1371	if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
		1372	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1136		1373
1137	unless ($SIGPIPE_R) {	1374	$HAVE_ASYNC_INTERRUPT = 1;
		1375	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1376	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
		1377
		1378	} else {
		1379	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1380
1138	require Fcntl;	1381	require Fcntl;
1139		1382
1140	if (AnyEvent::WIN32) {	1383	if (AnyEvent::WIN32) {
1141	require AnyEvent::Util;	1384	require AnyEvent::Util;
1142		1385
…		…
1157	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1400	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1158		1401
1159	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1402	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1160	}	1403	}
1161		1404
1162	my $signal = uc $arg{signal}	1405	*signal = \&_signal;
1163	or Carp::croak "required option 'signal' is missing";	1406	&signal
1164
1165	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1166	$SIG{$signal} \|\|= sub {
1167	local $!;
1168	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1169	undef $SIG_EV{$signal};
1170	};
1171
1172	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1173	}	1407	}
1174		1408
1175	sub AnyEvent::Base::signal::DESTROY {	1409	sub AnyEvent::Base::signal::DESTROY {
1176	my ($signal, $cb) = @{$_[0]};	1410	my ($signal, $cb) = @{$_[0]};
1177		1411
		1412	_sig_del;
		1413
1178	delete $SIG_CB{$signal}{$cb};	1414	delete $SIG_CB{$signal}{$cb};
1179		1415
		1416	$HAVE_ASYNC_INTERRUPT
		1417	? delete $SIG_ASY{$signal}
1180	# delete doesn't work with older perls - they then	1418	: # delete doesn't work with older perls - they then
1181	# print weird messages, or just unconditionally exit	1419	# print weird messages, or just unconditionally exit
1182	# instead of getting the default action.	1420	# instead of getting the default action.
		1421	undef $SIG{$signal}
1183	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };	1422	unless keys %{ $SIG_CB{$signal} };
1184	}	1423	}
1185		1424
1186	# default implementation for ->child	1425	# default implementation for ->child
1187		1426
1188	our %PID_CB;	1427	our %PID_CB;
1189	our $CHLD_W;	1428	our $CHLD_W;
1190	our $CHLD_DELAY_W;	1429	our $CHLD_DELAY_W;
1191	our $WNOHANG;	1430	our $WNOHANG;
1192		1431
		1432	sub _emit_childstatus($$) {
		1433	my (undef, $rpid, $rstatus) = @_;
		1434
		1435	$_->($rpid, $rstatus)
		1436	for values %{ $PID_CB{$rpid} \|\| {} },
		1437	values %{ $PID_CB{0} \|\| {} };
		1438	}
		1439
1193	sub _sigchld {	1440	sub _sigchld {
		1441	my $pid;
		1442
		1443	AnyEvent->_emit_childstatus ($pid, $?)
1194	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1444	while ($pid = waitpid -1, $WNOHANG) > 0;
1195	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),
1196	(values %{ $PID_CB{0} \|\| {} });
1197	}
1198	}	1445	}
1199		1446
1200	sub child {	1447	sub child {
1201	my (undef, %arg) = @_;	1448	my (undef, %arg) = @_;
1202		1449
1203	defined (my $pid = $arg{pid} + 0)	1450	defined (my $pid = $arg{pid} + 0)
1204	or Carp::croak "required option 'pid' is missing";	1451	or Carp::croak "required option 'pid' is missing";
1205		1452
1206	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1453	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1207		1454
		1455	# WNOHANG is almost cetrainly 1 everywhere
		1456	$WNOHANG \|\|= $^O =~ /^(?:openbsd\|netbsd\|linux\|freebsd\|cygwin\|MSWin32)$/
		1457	? 1
1208	$WNOHANG \|\|= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;	1458	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
1209		1459
1210	unless ($CHLD_W) {	1460	unless ($CHLD_W) {
1211	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1461	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1212	# child could be a zombie already, so make at least one round	1462	# child could be a zombie already, so make at least one round
1213	&_sigchld;	1463	&_sigchld;
…		…
1265		1515
1266	our @ISA = AnyEvent::CondVar::Base::;	1516	our @ISA = AnyEvent::CondVar::Base::;
1267		1517
1268	package AnyEvent::CondVar::Base;	1518	package AnyEvent::CondVar::Base;
1269		1519
1270	use overload	1520	#use overload
1271	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1521	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1272	fallback => 1;	1522	# fallback => 1;
		1523
		1524	# save 300+ kilobytes by dirtily hardcoding overloading
		1525	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1526	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1527	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1528	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1529
		1530	our $WAITING;
1273		1531
1274	sub _send {	1532	sub _send {
1275	# nop	1533	# nop
1276	}	1534	}
1277		1535
…		…
1290	sub ready {	1548	sub ready {
1291	$_[0]{_ae_sent}	1549	$_[0]{_ae_sent}
1292	}	1550	}
1293		1551
1294	sub _wait {	1552	sub _wait {
		1553	$WAITING
		1554	and !$_[0]{_ae_sent}
		1555	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1556
		1557	local $WAITING = 1;
1295	AnyEvent->one_event while !$_[0]{_ae_sent};	1558	AnyEvent->one_event while !$_[0]{_ae_sent};
1296	}	1559	}
1297		1560
1298	sub recv {	1561	sub recv {
1299	$_[0]->_wait;	1562	$_[0]->_wait;
…		…
1361	C<PERL_ANYEVENT_MODEL>.	1624	C<PERL_ANYEVENT_MODEL>.
1362		1625
1363	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1626	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1364	model it chooses.	1627	model it chooses.
1365		1628
		1629	When set to C<8> or higher, then AnyEvent will report extra information on
		1630	which optional modules it loads and how it implements certain features.
		1631
1366	=item C<PERL_ANYEVENT_STRICT>	1632	=item C<PERL_ANYEVENT_STRICT>
1367		1633
1368	AnyEvent does not do much argument checking by default, as thorough	1634	AnyEvent does not do much argument checking by default, as thorough
1369	argument checking is very costly. Setting this variable to a true value	1635	argument checking is very costly. Setting this variable to a true value
1370	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1636	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1371	check the arguments passed to most method calls. If it finds any problems	1637	check the arguments passed to most method calls. If it finds any problems,
1372	it will croak.	1638	it will croak.
1373		1639
1374	In other words, enables "strict" mode.	1640	In other words, enables "strict" mode.
1375		1641
1376	Unlike C<use strict>, it is definitely recommended ot keep it off in	1642	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1377	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1643	>>, it is definitely recommended to keep it off in production. Keeping
1378	developing programs can be very useful, however.	1644	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1645	can be very useful, however.
1379		1646
1380	=item C<PERL_ANYEVENT_MODEL>	1647	=item C<PERL_ANYEVENT_MODEL>
1381		1648
1382	This can be used to specify the event model to be used by AnyEvent, before	1649	This can be used to specify the event model to be used by AnyEvent, before
1383	auto detection and -probing kicks in. It must be a string consisting	1650	auto detection and -probing kicks in. It must be a string consisting
…		…
1426		1693
1427	=item C<PERL_ANYEVENT_MAX_FORKS>	1694	=item C<PERL_ANYEVENT_MAX_FORKS>
1428		1695
1429	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1696	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1430	will create in parallel.	1697	will create in parallel.
		1698
		1699	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1700
		1701	The default value for the C<max_outstanding> parameter for the default DNS
		1702	resolver - this is the maximum number of parallel DNS requests that are
		1703	sent to the DNS server.
		1704
		1705	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1706
		1707	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1708	configuration) in the default resolver. When set to the empty string, no
		1709	default config will be used.
		1710
		1711	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1712
		1713	When neither C<ca_file> nor C<ca_path> was specified during
		1714	L<AnyEvent::TLS> context creation, and either of these environment
		1715	variables exist, they will be used to specify CA certificate locations
		1716	instead of a system-dependent default.
		1717
		1718	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1719
		1720	When these are set to C<1>, then the respective modules are not
		1721	loaded. Mostly good for testing AnyEvent itself.
1431		1722
1432	=back	1723	=back
1433		1724
1434	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1725	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1435		1726
…		…
1680	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	1971	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1681	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	1972	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1682	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	1973	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1683	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	1974	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1684	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	1975	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		1976	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		1977	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1685	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	1978	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1686	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	1979	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1687	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	1980	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1688	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	1981	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1689		1982
…		…
1718	performance becomes really bad with lots of file descriptors (and few of	2011	performance becomes really bad with lots of file descriptors (and few of
1719	them active), of course, but this was not subject of this benchmark.	2012	them active), of course, but this was not subject of this benchmark.
1720		2013
1721	The C<Event> module has a relatively high setup and callback invocation	2014	The C<Event> module has a relatively high setup and callback invocation
1722	cost, but overall scores in on the third place.	2015	cost, but overall scores in on the third place.
		2016
		2017	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2018	when using its pure perl backend.
1723		2019
1724	C<Glib>'s memory usage is quite a bit higher, but it features a	2020	C<Glib>'s memory usage is quite a bit higher, but it features a
1725	faster callback invocation and overall ends up in the same class as	2021	faster callback invocation and overall ends up in the same class as
1726	C<Event>. However, Glib scales extremely badly, doubling the number of	2022	C<Event>. However, Glib scales extremely badly, doubling the number of
1727	watchers increases the processing time by more than a factor of four,	2023	watchers increases the processing time by more than a factor of four,
…		…
1805	it to another server. This includes deleting the old timeout and creating	2101	it to another server. This includes deleting the old timeout and creating
1806	a new one that moves the timeout into the future.	2102	a new one that moves the timeout into the future.
1807		2103
1808	=head3 Results	2104	=head3 Results
1809		2105
1810	name sockets create request	2106	name sockets create request
1811	EV 20000 69.01 11.16	2107	EV 20000 69.01 11.16
1812	Perl 20000 73.32 35.87	2108	Perl 20000 73.32 35.87
		2109	IOAsync 20000 157.00 98.14 epoll
		2110	IOAsync 20000 159.31 616.06 poll
1813	Event 20000 212.62 257.32	2111	Event 20000 212.62 257.32
1814	Glib 20000 651.16 1896.30	2112	Glib 20000 651.16 1896.30
1815	POE 20000 349.67 12317.24 uses POE::Loop::Event	2113	POE 20000 349.67 12317.24 uses POE::Loop::Event
1816		2114
1817	=head3 Discussion	2115	=head3 Discussion
1818		2116
1819	This benchmark I<does> measure scalability and overall performance of the	2117	This benchmark I<does> measure scalability and overall performance of the
1820	particular event loop.	2118	particular event loop.
…		…
1822	EV is again fastest. Since it is using epoll on my system, the setup time	2120	EV is again fastest. Since it is using epoll on my system, the setup time
1823	is relatively high, though.	2121	is relatively high, though.
1824		2122
1825	Perl surprisingly comes second. It is much faster than the C-based event	2123	Perl surprisingly comes second. It is much faster than the C-based event
1826	loops Event and Glib.	2124	loops Event and Glib.
		2125
		2126	IO::Async performs very well when using its epoll backend, and still quite
		2127	good compared to Glib when using its pure perl backend.
1827		2128
1828	Event suffers from high setup time as well (look at its code and you will	2129	Event suffers from high setup time as well (look at its code and you will
1829	understand why). Callback invocation also has a high overhead compared to	2130	understand why). Callback invocation also has a high overhead compared to
1830	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2131	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1831	uses select or poll in basically all documented configurations.	2132	uses select or poll in basically all documented configurations.
…		…
1900		2201
1901	Recently I was told about the benchmark in the IO::Lambda manpage, which	2202	Recently I was told about the benchmark in the IO::Lambda manpage, which
1902	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark	2203	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
1903	simply compares IO::Lambda with POE, and IO::Lambda looks better (which	2204	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
1904	shouldn't come as a surprise to anybody). As such, the benchmark is	2205	shouldn't come as a surprise to anybody). As such, the benchmark is
1905	fine, and shows that the AnyEvent backend from IO::Lambda isn't very	2206	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
1906	optimal. But how would AnyEvent compare when used without the extra	2207	very optimal. But how would AnyEvent compare when used without the extra
1907	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.	2208	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
1908		2209
1909	The benchmark itself creates an echo-server, and then, for 500 times,	2210	The benchmark itself creates an echo-server, and then, for 500 times,
1910	connects to the echo server, sends a line, waits for the reply, and then	2211	connects to the echo server, sends a line, waits for the reply, and then
1911	creates the next connection. This is a rather bad benchmark, as it doesn't	2212	creates the next connection. This is a rather bad benchmark, as it doesn't
1912	test the efficiency of the framework, but it is a benchmark nevertheless.	2213	test the efficiency of the framework or much non-blocking I/O, but it is a
		2214	benchmark nevertheless.
1913		2215
1914	name runtime	2216	name runtime
1915	Lambda/select 0.330 sec	2217	Lambda/select 0.330 sec
1916	+ optimized 0.122 sec	2218	+ optimized 0.122 sec
1917	Lambda/AnyEvent 0.327 sec	2219	Lambda/AnyEvent 0.327 sec
…		…
1923		2225
1924	AnyEvent/select/nb 0.085 sec	2226	AnyEvent/select/nb 0.085 sec
1925	AnyEvent/EV/nb 0.068 sec	2227	AnyEvent/EV/nb 0.068 sec
1926	+state machine 0.134 sec	2228	+state machine 0.134 sec
1927		2229
1928	The benchmark is also a bit unfair (my fault) - the IO::Lambda	2230	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
1929	benchmarks actually make blocking connects and use 100% blocking I/O,	2231	benchmarks actually make blocking connects and use 100% blocking I/O,
1930	defeating the purpose of an event-based solution. All of the newly	2232	defeating the purpose of an event-based solution. All of the newly
1931	written AnyEvent benchmarks use 100% non-blocking connects (using	2233	written AnyEvent benchmarks use 100% non-blocking connects (using
1932	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS	2234	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
1933	resolver), so AnyEvent is at a disadvantage here as non-blocking connects	2235	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
1934	generally require a lot more bookkeeping and event handling than blocking	2236	generally require a lot more bookkeeping and event handling than blocking
1935	connects (which involve a single syscall only).	2237	connects (which involve a single syscall only).
1936		2238
1937	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which	2239	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
1938	offers similar expressive power as POE and IO::Lambda (using conventional	2240	offers similar expressive power as POE and IO::Lambda, using conventional
1939	Perl syntax), which means both the echo server and the client are 100%	2241	Perl syntax. This means that both the echo server and the client are 100%
1940	non-blocking w.r.t. I/O, further placing it at a disadvantage.	2242	non-blocking, further placing it at a disadvantage.
1941		2243
1942	As you can see, AnyEvent + EV even beats the hand-optimised "raw sockets	2244	As you can see, the AnyEvent + EV combination even beats the
1943	benchmark", while AnyEvent + its pure perl backend easily beats	2245	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
1944	IO::Lambda and POE.	2246	backend easily beats IO::Lambda and POE.
1945		2247
1946	And even the 100% non-blocking version written using the high-level (and	2248	And even the 100% non-blocking version written using the high-level (and
1947	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda,	2249	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
1948	even thought it does all of DNS, tcp-connect and socket I/O in a	2250	large margin, even though it does all of DNS, tcp-connect and socket I/O
1949	non-blocking way.	2251	in a non-blocking way.
1950		2252
1951	The two AnyEvent benchmarks can be found as F<eg/ae0.pl> and F<eg/ae2.pl>	2253	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
1952	in the AnyEvent distribution, the remaining benchmarks are part of the	2254	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
1953	IO::lambda distribution and were used without any changes.	2255	part of the IO::lambda distribution and were used without any changes.
1954		2256
1955		2257
1956	=head1 SIGNALS	2258	=head1 SIGNALS
1957		2259
1958	AnyEvent currently installs handlers for these signals:	2260	AnyEvent currently installs handlers for these signals:
…		…
1962	=item SIGCHLD	2264	=item SIGCHLD
1963		2265
1964	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2266	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1965	emulation for event loops that do not support them natively. Also, some	2267	emulation for event loops that do not support them natively. Also, some
1966	event loops install a similar handler.	2268	event loops install a similar handler.
		2269
		2270	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2271	AnyEvent will reset it to default, to avoid losing child exit statuses.
1967		2272
1968	=item SIGPIPE	2273	=item SIGPIPE
1969		2274
1970	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2275	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1971	when AnyEvent gets loaded.	2276	when AnyEvent gets loaded.
…		…
1983		2288
1984	=back	2289	=back
1985		2290
1986	=cut	2291	=cut
1987		2292
		2293	undef $SIG{CHLD}
		2294	if $SIG{CHLD} eq 'IGNORE';
		2295
1988	$SIG{PIPE} = sub { }	2296	$SIG{PIPE} = sub { }
1989	unless defined $SIG{PIPE};	2297	unless defined $SIG{PIPE};
		2298
		2299	=head1 RECOMMENDED/OPTIONAL MODULES
		2300
		2301	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2302	it's built-in modules) are required to use it.
		2303
		2304	That does not mean that AnyEvent won't take advantage of some additional
		2305	modules if they are installed.
		2306
		2307	This section epxlains which additional modules will be used, and how they
		2308	affect AnyEvent's operetion.
		2309
		2310	=over 4
		2311
		2312	=item L<Async::Interrupt>
		2313
		2314	This slightly arcane module is used to implement fast signal handling: To
		2315	my knowledge, there is no way to do completely race-free and quick
		2316	signal handling in pure perl. To ensure that signals still get
		2317	delivered, AnyEvent will start an interval timer to wake up perl (and
		2318	catch the signals) with some delay (default is 10 seconds, look for
		2319	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2320
		2321	If this module is available, then it will be used to implement signal
		2322	catching, which means that signals will not be delayed, and the event loop
		2323	will not be interrupted regularly, which is more efficient (And good for
		2324	battery life on laptops).
		2325
		2326	This affects not just the pure-perl event loop, but also other event loops
		2327	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2328
		2329	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2330	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2331	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2332	does nothing for those backends.
		2333
		2334	=item L<EV>
		2335
		2336	This module isn't really "optional", as it is simply one of the backend
		2337	event loops that AnyEvent can use. However, it is simply the best event
		2338	loop available in terms of features, speed and stability: It supports
		2339	the AnyEvent API optimally, implements all the watcher types in XS, does
		2340	automatic timer adjustments even when no monotonic clock is available,
		2341	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2342	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2343	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2344
		2345	=item L<Guard>
		2346
		2347	The guard module, when used, will be used to implement
		2348	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2349	lot less memory), but otherwise doesn't affect guard operation much. It is
		2350	purely used for performance.
		2351
		2352	=item L<JSON> and L<JSON::XS>
		2353
		2354	This module is required when you want to read or write JSON data via
		2355	L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2356	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2357
		2358	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2359	installed.
		2360
		2361	=item L<Net::SSLeay>
		2362
		2363	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2364	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2365	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2366
		2367	=item L<Time::HiRes>
		2368
		2369	This module is part of perl since release 5.008. It will be used when the
		2370	chosen event library does not come with a timing source on it's own. The
		2371	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2372	try to use a monotonic clock for timing stability.
		2373
		2374	=back
1990		2375
1991		2376
1992	=head1 FORK	2377	=head1 FORK
1993		2378
1994	Most event libraries are not fork-safe. The ones who are usually are	2379	Most event libraries are not fork-safe. The ones who are usually are
1995	because they rely on inefficient but fork-safe C<select> or C<poll>	2380	because they rely on inefficient but fork-safe C<select> or C<poll>
1996	calls. Only L<EV> is fully fork-aware.	2381	calls. Only L<EV> is fully fork-aware.
1997		2382
1998	If you have to fork, you must either do so I<before> creating your first	2383	If you have to fork, you must either do so I<before> creating your first
1999	watcher OR you must not use AnyEvent at all in the child.	2384	watcher OR you must not use AnyEvent at all in the child OR you must do
		2385	something completely out of the scope of AnyEvent.
2000		2386
2001		2387
2002	=head1 SECURITY CONSIDERATIONS	2388	=head1 SECURITY CONSIDERATIONS
2003		2389
2004	AnyEvent can be forced to load any event model via	2390	AnyEvent can be forced to load any event model via
…		…
2018	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2404	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
2019	be used to probe what backend is used and gain other information (which is	2405	be used to probe what backend is used and gain other information (which is
2020	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2406	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
2021	$ENV{PERL_ANYEVENT_STRICT}.	2407	$ENV{PERL_ANYEVENT_STRICT}.
2022		2408
		2409	Note that AnyEvent will remove I<all> environment variables starting with
		2410	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2411	enabled.
		2412
2023		2413
2024	=head1 BUGS	2414	=head1 BUGS
2025		2415
2026	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2416	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
2027	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2417	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
…		…
2038	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2428	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2039		2429
2040	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2430	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2041	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2431	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2042	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2432	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2043	L<AnyEvent::Impl::POE>.	2433	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2044		2434
2045	Non-blocking file handles, sockets, TCP clients and	2435	Non-blocking file handles, sockets, TCP clients and
2046	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2436	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2047		2437
2048	Asynchronous DNS: L<AnyEvent::DNS>.	2438	Asynchronous DNS: L<AnyEvent::DNS>.
2049		2439
2050	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2440	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2441	L<Coro::Event>,
2051		2442
2052	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2443	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2444	L<AnyEvent::HTTP>.
2053		2445
2054		2446
2055	=head1 AUTHOR	2447	=head1 AUTHOR
2056		2448
2057	Marc Lehmann <schmorp@schmorp.de>	2449	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.217 by root, Tue Jun 23 23:37:32 2009 UTC vs. Revision 1.259 by root, Tue Jul 28 02:07:18 2009 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.217 by root, Tue Jun 23 23:37:32 2009 UTC vs.
Revision 1.259 by root, Tue Jul 28 02:07:18 2009 UTC