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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.208 by root, Sun Apr 26 18:12:53 2009 UTC vs.
Revision 1.263 by root, Wed Jul 29 12:39:21 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, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
		6	and POE are various supported event loops/environments.
6		7
7	=head1 SYNOPSIS	8	=head1 SYNOPSIS
8		9
9	use AnyEvent;	10	use AnyEvent;
10		11
39	=head1 INTRODUCTION/TUTORIAL	40	=head1 INTRODUCTION/TUTORIAL
40		41
41	This manpage is mainly a reference manual. If you are interested	42	This manpage is mainly a reference manual. If you are interested
42	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
43	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.
44		53
45	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	54	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
46		55
47	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
48	nowadays. So what is different about AnyEvent?	57	nowadays. So what is different about AnyEvent?
…		…
175	=head2 I/O WATCHERS	184	=head2 I/O WATCHERS
176		185
177	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
178	with the following mandatory key-value pairs as arguments:	187	with the following mandatory key-value pairs as arguments:
179		188
180	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
181	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
182	handle). Note that only file handles pointing to things for which	191	handle). Note that only file handles pointing to things for which
183	non-blocking operation makes sense are allowed. This includes sockets,	192	non-blocking operation makes sense are allowed. This includes sockets,
184	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
185	or block devices.	194	or block devices.
…		…
360	invocation, and callback invocation will be synchronous. Synchronous means	369	invocation, and callback invocation will be synchronous. Synchronous means
361	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,
362	but it is guaranteed not to interrupt any other callbacks.	371	but it is guaranteed not to interrupt any other callbacks.
363		372
364	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
365	between multiple watchers.	374	between multiple watchers, and AnyEvent will ensure that signals will not
		375	interrupt your program at bad times.
366		376
367	This watcher might use C<%SIG>, so programs overwriting those signals	377	This watcher might use C<%SIG> (depending on the event loop used),
368	directly will likely not work correctly.	378	so programs overwriting those signals directly will likely not work
		379	correctly.
369		380
370	Example: exit on SIGINT	381	Example: exit on SIGINT
371		382
372	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	383	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
373		384
		385	=head3 Signal Races, Delays and Workarounds
		386
		387	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		388	callbacks to signals in a generic way, which is a pity, as you cannot do
		389	race-free signal handling in perl. AnyEvent will try to do it's best, but
		390	in some cases, signals will be delayed. The maximum time a signal might
		391	be delayed is specified in C<$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
374	=head2 CHILD PROCESS WATCHERS	401	=head2 CHILD PROCESS WATCHERS
375		402
376	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.
377		404
378	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,
379	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
380	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
381	any trace events (stopped/continued).	408	finished and an exit status is available, not on any trace events
		409	(stopped/continued).
382		410
383	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
384	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
385	callback arguments.	413	callback arguments.
386		414
…		…
391		419
392	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
393	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
394	have exited already (and no SIGCHLD will be sent anymore).	422	have exited already (and no SIGCHLD will be sent anymore).
395		423
396	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
397	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
398	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.
399		430
400	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
401	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
402	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.
403		439
404	Example: fork a process and wait for it	440	Example: fork a process and wait for it
405		441
406	my $done = AnyEvent->condvar;	442	my $done = AnyEvent->condvar;
407		443
…		…
458		494
459	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
460	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
461	will actively watch for new events and call your callbacks.	497	will actively watch for new events and call your callbacks.
462		498
463	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
464	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).
465		501
466	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
467	because they represent a condition that must become true.	503	because they represent a condition that must become true.
468		504
		505	Now is probably a good time to look at the examples further below.
		506
469	Condition variables can be created by calling the C<< AnyEvent->condvar	507	Condition variables can be created by calling the C<< AnyEvent->condvar
470	>> method, usually without arguments. The only argument pair allowed is	508	>> method, usually without arguments. The only argument pair allowed is
471
472	C<cb>, which specifies a callback to be called when the condition variable	509	C<cb>, which specifies a callback to be called when the condition variable
473	becomes true, with the condition variable as the first argument (but not	510	becomes true, with the condition variable as the first argument (but not
474	the results).	511	the results).
475		512
476	After creation, the condition variable is "false" until it becomes "true"	513	After creation, the condition variable is "false" until it becomes "true"
…		…
481	Condition variables are similar to callbacks, except that you can	518	Condition variables are similar to callbacks, except that you can
482	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
483	in time where multiple outstanding events have been processed. And yet	520	in time where multiple outstanding events have been processed. And yet
484	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
485	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
486	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.
487		525
488	Condition variables are very useful to signal that something has finished,	526	Condition variables are very useful to signal that something has finished,
489	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,
490	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
491	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
…		…
525	after => 1,	563	after => 1,
526	cb => sub { $result_ready->send },	564	cb => sub { $result_ready->send },
527	);	565	);
528		566
529	# this "blocks" (while handling events) till the callback	567	# this "blocks" (while handling events) till the callback
530	# calls send	568	# calls -<send
531	$result_ready->recv;	569	$result_ready->recv;
532		570
533	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
534	condition variables are also code references.	572	variables are also callable directly.
535		573
536	my $done = AnyEvent->condvar;	574	my $done = AnyEvent->condvar;
537	my $delay = AnyEvent->timer (after => 5, cb => $done);	575	my $delay = AnyEvent->timer (after => 5, cb => $done);
538	$done->recv;	576	$done->recv;
539		577
…		…
545		583
546	...	584	...
547		585
548	my @info = $couchdb->info->recv;	586	my @info = $couchdb->info->recv;
549		587
550	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
551	results are available:	589	results are available:
552		590
553	$couchdb->info->cb (sub {	591	$couchdb->info->cb (sub {
554	my @info = $_[0]->recv;	592	my @info = $_[0]->recv;
555	});	593	});
…		…
573	immediately from within send.	611	immediately from within send.
574		612
575	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
576	future C<< ->recv >> calls.	614	future C<< ->recv >> calls.
577		615
578	Condition variables are overloaded so one can call them directly	616	Condition variables are overloaded so one can call them directly (as if
579	(as a code reference). Calling them directly is the same as calling	617	they were a code reference). Calling them directly is the same as calling
580	C<send>. Note, however, that many C-based event loops do not handle	618	C<send>.
581	overloading, so as tempting as it may be, passing a condition variable
582	instead of a callback does not work. Both the pure perl and EV loops
583	support overloading, however, as well as all functions that use perl to
584	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
585	example).
586		619
587	=item $cv->croak ($error)	620	=item $cv->croak ($error)
588		621
589	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
590	C<Carp::croak> with the given error message/object/scalar.	623	C<Carp::croak> with the given error message/object/scalar.
591		624
592	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
593	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.
594		631
595	=item $cv->begin ([group callback])	632	=item $cv->begin ([group callback])
596		633
597	=item $cv->end	634	=item $cv->end
598
599	These two methods are EXPERIMENTAL and MIGHT CHANGE.
600		635
601	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
602	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
603	to use a condition variable for the whole process.	638	to use a condition variable for the whole process.
604		639
…		…
606	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
607	>>, 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
608	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
609	callback was set, C<send> will be called without any arguments.	644	callback was set, C<send> will be called without any arguments.
610		645
611	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:
612		677
613	my $cv = AnyEvent->condvar;	678	my $cv = AnyEvent->condvar;
614		679
615	my %result;	680	my %result;
616	$cv->begin (sub { $cv->send (\%result) });	681	$cv->begin (sub { $cv->send (\%result) });
…		…
636	loop, which serves two important purposes: first, it sets the callback	701	loop, which serves two important purposes: first, it sets the callback
637	to be called once the counter reaches C<0>, and second, it ensures that	702	to be called once the counter reaches C<0>, and second, it ensures that
638	C<send> is called even when C<no> hosts are being pinged (the loop	703	C<send> is called even when C<no> hosts are being pinged (the loop
639	doesn't execute once).	704	doesn't execute once).
640		705
641	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
642	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
643	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
644	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>.
645		711
646	=back	712	=back
647		713
648	=head3 METHODS FOR CONSUMERS	714	=head3 METHODS FOR CONSUMERS
649		715
…		…
665	function will call C<croak>.	731	function will call C<croak>.
666		732
667	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,
668	in scalar context only the first one will be returned.	734	in scalar context only the first one will be returned.
669		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
670	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
671	(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
672	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
673	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
674	condition variables with some kind of request results and supporting	747	condition variables with some kind of request results and supporting
675	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,
676	while still supporting blocking waits if the caller so desires).	749	while still supporting blocking waits if the caller so desires).
677		750
678	Another reason I<never> to C<< ->recv >> in a module is that you cannot
679	sensibly have two C<< ->recv >>'s in parallel, as that would require
680	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
681	can supply.
682
683	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
684	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
685	versions and also integrates coroutines into AnyEvent, making blocking
686	C<< ->recv >> calls perfectly safe as long as they are done from another
687	coroutine (one that doesn't run the event loop).
688
689	You can ensure that C<< -recv >> never blocks by setting a callback and	751	You can ensure that C<< -recv >> never blocks by setting a callback and
690	only calling C<< ->recv >> from within that callback (or at a later	752	only calling C<< ->recv >> from within that callback (or at a later
691	time). This will work even when the event loop does not support blocking	753	time). This will work even when the event loop does not support blocking
692	waits otherwise.	754	waits otherwise.
693		755
…		…
706	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
707	is guaranteed not to block.	769	is guaranteed not to block.
708		770
709	=back	771	=back
710		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
711	=head1 GLOBAL VARIABLES AND FUNCTIONS	841	=head1 GLOBAL VARIABLES AND FUNCTIONS
712		842
		843	These are not normally required to use AnyEvent, but can be useful to
		844	write AnyEvent extension modules.
		845
713	=over 4	846	=over 4
714		847
715	=item $AnyEvent::MODEL	848	=item $AnyEvent::MODEL
716		849
717	Contains C<undef> until the first watcher is being created. Then it	850	Contains C<undef> until the first watcher is being created, before the
		851	backend has been autodetected.
		852
718	contains the event model that is being used, which is the name of the	853	Afterwards it contains the event model that is being used, which is the
719	Perl class implementing the model. This class is usually one of the	854	name of the Perl class implementing the model. This class is usually one
720	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	855	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
721	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	856	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
722		857	will be C<urxvt::anyevent>).
723	The known classes so far are:
724
725	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
726	AnyEvent::Impl::Event based on Event, second best choice.
727	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
728	AnyEvent::Impl::Glib based on Glib, third-best choice.
729	AnyEvent::Impl::Tk based on Tk, very bad choice.
730	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
731	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
732	AnyEvent::Impl::POE based on POE, not generic enough for full support.
733
734	There is no support for WxWidgets, as WxWidgets has no support for
735	watching file handles. However, you can use WxWidgets through the
736	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
737	second, which was considered to be too horrible to even consider for
738	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
739	it's adaptor.
740
741	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
742	autodetecting them.
743		858
744	=item AnyEvent::detect	859	=item AnyEvent::detect
745		860
746	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	861	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
747	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
748	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
749	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>.
750		868
751	=item $guard = AnyEvent::post_detect { BLOCK }	869	=item $guard = AnyEvent::post_detect { BLOCK }
752		870
753	Arranges for the code block to be executed as soon as the event model is	871	Arranges for the code block to be executed as soon as the event model is
754	autodetected (or immediately if this has already happened).	872	autodetected (or immediately if this has already happened).
755		873
		874	The block will be executed I<after> the actual backend has been detected
		875	(C<$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
756	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
757	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
758	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 \|\|= $guard;
759		905
760	=item @AnyEvent::post_detect	906	=item @AnyEvent::post_detect
761		907
762	If there are any code references in this array (you can C<push> to it	908	If there are any code references in this array (you can C<push> to it
763	before or after loading AnyEvent), then they will called directly after	909	before or after loading AnyEvent), then they will called directly after
764	the event loop has been chosen.	910	the event loop has been chosen.
765		911
766	You should check C<$AnyEvent::MODEL> before adding to this array, though:	912	You should check C<$AnyEvent::MODEL> before adding to this array, though:
767	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
768	and the array will be ignored.	914	array will be ignored.
769		915
770	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.
771		923
772	=back	924	=back
773		925
774	=head1 WHAT TO DO IN A MODULE	926	=head1 WHAT TO DO IN A MODULE
775		927
…		…
830		982
831		983
832	=head1 OTHER MODULES	984	=head1 OTHER MODULES
833		985
834	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
835	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
836	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
837	available via CPAN.	989	come with AnyEvent, most are available via CPAN.
838		990
839	=over 4	991	=over 4
840		992
841	=item L<AnyEvent::Util>	993	=item L<AnyEvent::Util>
842		994
…		…
851		1003
852	=item L<AnyEvent::Handle>	1004	=item L<AnyEvent::Handle>
853		1005
854	Provide read and write buffers, manages watchers for reads and writes,	1006	Provide read and write buffers, manages watchers for reads and writes,
855	supports raw and formatted I/O, I/O queued and fully transparent and	1007	supports raw and formatted I/O, I/O queued and fully transparent and
856	non-blocking SSL/TLS.	1008	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
857		1009
858	=item L<AnyEvent::DNS>	1010	=item L<AnyEvent::DNS>
859		1011
860	Provides rich asynchronous DNS resolver capabilities.	1012	Provides rich asynchronous DNS resolver capabilities.
861		1013
…		…
889		1041
890	=item L<AnyEvent::GPSD>	1042	=item L<AnyEvent::GPSD>
891		1043
892	A non-blocking interface to gpsd, a daemon delivering GPS information.	1044	A non-blocking interface to gpsd, a daemon delivering GPS information.
893		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
894	=item L<AnyEvent::IGS>	1055	=item L<AnyEvent::IGS>
895		1056
896	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
897	L<App::IGS>).	1058	L<App::IGS>).
898		1059
899	=item L<AnyEvent::IRC>
900
901	AnyEvent based IRC client module family (replacing the older Net::IRC3).
902
903	=item L<Net::XMPP2>
904
905	AnyEvent based XMPP (Jabber protocol) module family.
906
907	=item L<Net::FCP>	1060	=item L<Net::FCP>
908		1061
909	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1062	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
910	of AnyEvent.	1063	of AnyEvent.
911		1064
…		…
915		1068
916	=item L<Coro>	1069	=item L<Coro>
917		1070
918	Has special support for AnyEvent via L<Coro::AnyEvent>.	1071	Has special support for AnyEvent via L<Coro::AnyEvent>.
919		1072
920	=item L<IO::Lambda>
921
922	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
923
924	=back	1073	=back
925		1074
926	=cut	1075	=cut
927		1076
928	package AnyEvent;	1077	package AnyEvent;
929		1078
		1079	# basically a tuned-down version of common::sense
		1080	sub common_sense {
930	no warnings;	1081	# no warnings
		1082	${^WARNING_BITS} ^= ${^WARNING_BITS};
931	use strict qw(vars subs);	1083	# use strict vars subs
		1084	$^H \|= 0x00000600;
		1085	}
932		1086
		1087	BEGIN { AnyEvent::common_sense }
		1088
933	use Carp;	1089	use Carp ();
934		1090
935	our $VERSION = 4.4;	1091	our $VERSION = 4.881;
936	our $MODEL;	1092	our $MODEL;
937		1093
938	our $AUTOLOAD;	1094	our $AUTOLOAD;
939	our @ISA;	1095	our @ISA;
940		1096
941	our @REGISTRY;	1097	our @REGISTRY;
942		1098
943	our $WIN32;	1099	our $WIN32;
944		1100
		1101	our $VERBOSE;
		1102
945	BEGIN {	1103	BEGIN {
946	my $win32 = ! ! ($^O =~ /mswin32/i);	1104	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
947	eval "sub WIN32(){ $win32 }";	1105	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
948	}
949		1106
		1107	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1108	if ${^TAINT};
		1109
950	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1110	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1111
		1112	}
		1113
		1114	our $MAX_SIGNAL_LATENCY = 10;
951		1115
952	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred	1116	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
953		1117
954	{	1118	{
955	my $idx;	1119	my $idx;
…		…
957	for reverse split /\s,\s/,	1121	for reverse split /\s,\s/,
958	$ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";	1122	$ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
959	}	1123	}
960		1124
961	my @models = (	1125	my @models = (
962	[EV:: => AnyEvent::Impl::EV::],	1126	[EV:: => AnyEvent::Impl::EV:: , 1],
963	[Event:: => AnyEvent::Impl::Event::],	1127	[Event:: => AnyEvent::Impl::Event::, 1],
964	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1128	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
965	# everything below here will not be autoprobed	1129	# everything below here will not (normally) be autoprobed
966	# as the pureperl backend should work everywhere	1130	# as the pureperl backend should work everywhere
967	# 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
968	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1135	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
969	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
970	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
971	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1136	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
972	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1137	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
973	[Wx:: => AnyEvent::Impl::POE::],	1138	[Wx:: => AnyEvent::Impl::POE::],
974	[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
975	);	1147	);
976		1148
977	our %method = map +($_ => 1),	1149	our %method = map +($_ => 1),
978	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1150	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
979		1151
…		…
983	my ($cb) = @_;	1155	my ($cb) = @_;
984		1156
985	if ($MODEL) {	1157	if ($MODEL) {
986	$cb->();	1158	$cb->();
987		1159
988	1	1160	undef
989	} else {	1161	} else {
990	push @post_detect, $cb;	1162	push @post_detect, $cb;
991		1163
992	defined wantarray	1164	defined wantarray
993	? bless \$cb, "AnyEvent::Util::postdetect"	1165	? bless \$cb, "AnyEvent::Util::postdetect"
…		…
999	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1171	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1000	}	1172	}
1001		1173
1002	sub detect() {	1174	sub detect() {
1003	unless ($MODEL) {	1175	unless ($MODEL) {
1004	no strict 'refs';
1005	local $SIG{__DIE__};	1176	local $SIG{__DIE__};
1006		1177
1007	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1178	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1008	my $model = "AnyEvent::Impl::$1";	1179	my $model = "AnyEvent::Impl::$1";
1009	if (eval "require $model") {	1180	if (eval "require $model") {
1010	$MODEL = $model;	1181	$MODEL = $model;
1011	warn "AnyEvent: loaded model '$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 $VERBOSE >= 2;
1012	} else {	1183	} else {
1013	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1184	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1014	}	1185	}
1015	}	1186	}
1016		1187
1017	# check for already loaded models	1188	# check for already loaded models
1018	unless ($MODEL) {	1189	unless ($MODEL) {
1019	for (@REGISTRY, @models) {	1190	for (@REGISTRY, @models) {
1020	my ($package, $model) = @$_;	1191	my ($package, $model) = @$_;
1021	if (${"$package\::VERSION"} > 0) {	1192	if (${"$package\::VERSION"} > 0) {
1022	if (eval "require $model") {	1193	if (eval "require $model") {
1023	$MODEL = $model;	1194	$MODEL = $model;
1024	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1195	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1025	last;	1196	last;
1026	}	1197	}
1027	}	1198	}
1028	}	1199	}
1029		1200
1030	unless ($MODEL) {	1201	unless ($MODEL) {
1031	# try to load a model	1202	# try to autoload a model
1032
1033	for (@REGISTRY, @models) {	1203	for (@REGISTRY, @models) {
1034	my ($package, $model) = @$_;	1204	my ($package, $model, $autoload) = @$_;
		1205	if (
		1206	$autoload
1035	if (eval "require $package"	1207	and eval "require $package"
1036	and ${"$package\::VERSION"} > 0	1208	and ${"$package\::VERSION"} > 0
1037	and eval "require $model") {	1209	and eval "require $model"
		1210	) {
1038	$MODEL = $model;	1211	$MODEL = $model;
1039	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1212	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1040	last;	1213	last;
1041	}	1214	}
1042	}	1215	}
1043		1216
1044	$MODEL	1217	$MODEL
…		…
1060		1233
1061	sub AUTOLOAD {	1234	sub AUTOLOAD {
1062	(my $func = $AUTOLOAD) =~ s/.*://;	1235	(my $func = $AUTOLOAD) =~ s/.*://;
1063		1236
1064	$method{$func}	1237	$method{$func}
1065	or croak "$func: not a valid method for AnyEvent objects";	1238	or Carp::croak "$func: not a valid method for AnyEvent objects";
1066		1239
1067	detect unless $MODEL;	1240	detect unless $MODEL;
1068		1241
1069	my $class = shift;	1242	my $class = shift;
1070	$class->$func (@_);	1243	$class->$func (@_);
1071	}	1244	}
1072		1245
1073	# 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
1074	# to support binding more than one watcher per filehandle (they usually	1247	# to support binding more than one watcher per filehandle (they usually
1075	# allow only one watcher per fd, so we dup it to get a different one).	1248	# allow only one watcher per fd, so we dup it to get a different one).
1076	sub _dupfh($$$$) {	1249	sub _dupfh($$;$$) {
1077	my ($poll, $fh, $r, $w) = @_;	1250	my ($poll, $fh, $r, $w) = @_;
1078		1251
1079	# cygwin requires the fh mode to be matching, unix doesn't	1252	# cygwin requires the fh mode to be matching, unix doesn't
1080	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1253	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1081	: $poll eq "w" ? ($w, ">")
1082	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1083		1254
1084	open my $fh2, "$mode&" . fileno $fh	1255	open my $fh2, $mode, $fh
1085	or die "cannot dup() filehandle: $!,";	1256	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1086		1257
1087	# 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
1088		1259
1089	($fh2, $rw)	1260	($fh2, $rw)
1090	}	1261	}
1091		1262
1092	package AnyEvent::Base;	1263	package AnyEvent::Base;
1093		1264
1094	# default implementations for many methods	1265	# default implementations for many methods
1095		1266
1096	BEGIN {	1267	sub _time {
		1268	# probe for availability of Time::HiRes
1097	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;
1098	*_time = \&Time::HiRes::time;	1271	*_time = \&Time::HiRes::time;
1099	# if (eval "use POSIX (); (POSIX::times())...	1272	# if (eval "use POSIX (); (POSIX::times())...
1100	} else {	1273	} else {
		1274	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1101	*_time = sub { time }; # epic fail	1275	*_time = sub { time }; # epic fail
1102	}	1276	}
		1277
		1278	&_time
1103	}	1279	}
1104		1280
1105	sub time { _time }	1281	sub time { _time }
1106	sub now { _time }	1282	sub now { _time }
1107	sub now_update { }	1283	sub now_update { }
…		…
1112	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1288	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1113	}	1289	}
1114		1290
1115	# default implementation for ->signal	1291	# default implementation for ->signal
1116		1292
		1293	our $HAVE_ASYNC_INTERRUPT;
		1294
		1295	sub _have_async_interrupt() {
		1296	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1297	&& eval "use Async::Interrupt 1.0 (); 1")
		1298	unless defined $HAVE_ASYNC_INTERRUPT;
		1299
		1300	$HAVE_ASYNC_INTERRUPT
		1301	}
		1302
1117	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1303	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1304	our (%SIG_ASY, %SIG_ASY_W);
		1305	our ($SIG_COUNT, $SIG_TW);
1118		1306
1119	sub _signal_exec {	1307	sub _signal_exec {
		1308	$HAVE_ASYNC_INTERRUPT
		1309	? $SIGPIPE_R->drain
1120	sysread $SIGPIPE_R, my $dummy, 4;	1310	: sysread $SIGPIPE_R, my $dummy, 9;
1121		1311
1122	while (%SIG_EV) {	1312	while (%SIG_EV) {
1123	for (keys %SIG_EV) {	1313	for (keys %SIG_EV) {
1124	delete $SIG_EV{$_};	1314	delete $SIG_EV{$_};
1125	$_->() for values %{ $SIG_CB{$_} \|\| {} };	1315	$_->() for values %{ $SIG_CB{$_} \|\| {} };
1126	}	1316	}
1127	}	1317	}
1128	}	1318	}
1129		1319
		1320	# install a dummy wakeup watcher to reduce signal catching latency
		1321	sub _sig_add() {
		1322	unless ($SIG_COUNT++) {
		1323	# try to align timer on a full-second boundary, if possible
		1324	my $NOW = AnyEvent->now;
		1325
		1326	$SIG_TW = AnyEvent->timer (
		1327	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1328	interval => $MAX_SIGNAL_LATENCY,
		1329	cb => sub { }, # just for the PERL_ASYNC_CHECK
		1330	);
		1331	}
		1332	}
		1333
		1334	sub _sig_del {
		1335	undef $SIG_TW
		1336	unless --$SIG_COUNT;
		1337	}
		1338
		1339	our %SIGNAME2NUM;
		1340	our @SIGNUM2NAME;
		1341	our $_sig_name_init; $_sig_name_init = sub {
		1342	undef $_sig_name_init;
		1343
		1344	if (_have_async_interrupt) {
		1345	*sig2num = \&Async::Interrupt::sig2num;
		1346	*sig2name = \&Async::Interrupt::sig2name;
		1347	} else {
		1348	require Config;
		1349
		1350	@SIGNAME2NUM{ split ' ', $Config::Config{sig_name} }
		1351	= split ' ', $Config::Config{sig_num};
		1352	@SIGNUM2NAME[values %SIGNAME2NUM] = keys %SIGNAME2NUM;
		1353
		1354	*sig2num = sub($) {
		1355	$_[0] > 0 ? shift : $SIGNAME2NUM{+shift}
		1356	};
		1357	*sig2name = sub ($) {
		1358	$_[0] > 0 ? $SIGNUM2NAME[+shift] : shift
		1359	};
		1360	}
		1361	};
		1362
		1363	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1364	sub sig2name($) { &$_sig_name_init; &sig2name }
		1365
		1366	sub _signal {
		1367	my (undef, %arg) = @_;
		1368
		1369	my $signal = uc $arg{signal}
		1370	or Carp::croak "required option 'signal' is missing";
		1371
		1372	if ($HAVE_ASYNC_INTERRUPT) {
		1373	# async::interrupt
		1374
		1375	$signal = sig2num $signal;
		1376	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1377
		1378	$SIG_ASY{$signal} \|\|= new Async::Interrupt
		1379	cb => sub { undef $SIG_EV{$signal} },
		1380	signal => $signal,
		1381	pipe => [$SIGPIPE_R->filenos],
		1382	pipe_autodrain => 0,
		1383	;
		1384
		1385	} else {
		1386	# pure perl
		1387
		1388	# AE::Util has been loaded in signal
		1389	$signal = sig2name $signal;
		1390	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1391
		1392	$SIG{$signal} \|\|= sub {
		1393	local $!;
		1394	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1395	undef $SIG_EV{$signal};
		1396	};
		1397
		1398	# can't do signal processing without introducing races in pure perl,
		1399	# so limit the signal latency.
		1400	_sig_add;
		1401	}
		1402
		1403	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1404	}
		1405
1130	sub signal {	1406	sub signal {
1131	my (undef, %arg) = @_;	1407	# probe for availability of Async::Interrupt
		1408	if (_have_async_interrupt) {
		1409	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1132		1410
1133	unless ($SIGPIPE_R) {	1411	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1412	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
		1413
		1414	} else {
		1415	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1416
1134	require Fcntl;	1417	require Fcntl;
1135		1418
1136	if (AnyEvent::WIN32) {	1419	if (AnyEvent::WIN32) {
1137	require AnyEvent::Util;	1420	require AnyEvent::Util;
1138		1421
…		…
1141	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case	1424	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1142	} else {	1425	} else {
1143	pipe $SIGPIPE_R, $SIGPIPE_W;	1426	pipe $SIGPIPE_R, $SIGPIPE_W;
1144	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1427	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1145	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1428	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1429
		1430	# not strictly required, as $^F is normally 2, but let's make sure...
		1431	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1432	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1146	}	1433	}
1147		1434
1148	$SIGPIPE_R	1435	$SIGPIPE_R
1149	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1436	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1150		1437
1151	# not strictly required, as $^F is normally 2, but let's make sure...
1152	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1153	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1154
1155	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1438	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1156	}	1439	}
1157		1440
1158	my $signal = uc $arg{signal}	1441	*signal = \&_signal;
1159	or Carp::croak "required option 'signal' is missing";	1442	&signal
1160
1161	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1162	$SIG{$signal} \|\|= sub {
1163	local $!;
1164	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1165	undef $SIG_EV{$signal};
1166	};
1167
1168	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1169	}	1443	}
1170		1444
1171	sub AnyEvent::Base::signal::DESTROY {	1445	sub AnyEvent::Base::signal::DESTROY {
1172	my ($signal, $cb) = @{$_[0]};	1446	my ($signal, $cb) = @{$_[0]};
1173		1447
		1448	_sig_del;
		1449
1174	delete $SIG_CB{$signal}{$cb};	1450	delete $SIG_CB{$signal}{$cb};
1175		1451
		1452	$HAVE_ASYNC_INTERRUPT
		1453	? delete $SIG_ASY{$signal}
		1454	: # delete doesn't work with older perls - they then
		1455	# print weird messages, or just unconditionally exit
		1456	# instead of getting the default action.
		1457	undef $SIG{$signal}
1176	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };	1458	unless keys %{ $SIG_CB{$signal} };
1177	}	1459	}
1178		1460
1179	# default implementation for ->child	1461	# default implementation for ->child
1180		1462
1181	our %PID_CB;	1463	our %PID_CB;
1182	our $CHLD_W;	1464	our $CHLD_W;
1183	our $CHLD_DELAY_W;	1465	our $CHLD_DELAY_W;
1184	our $PID_IDLE;
1185	our $WNOHANG;	1466	our $WNOHANG;
1186		1467
1187	sub _child_wait {	1468	sub _emit_childstatus($$) {
1188	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1469	my (undef, $rpid, $rstatus) = @_;
		1470
		1471	$_->($rpid, $rstatus)
1189	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),	1472	for values %{ $PID_CB{$rpid} \|\| {} },
1190	(values %{ $PID_CB{0} \|\| {} });	1473	values %{ $PID_CB{0} \|\| {} };
1191	}
1192
1193	undef $PID_IDLE;
1194	}	1474	}
1195		1475
1196	sub _sigchld {	1476	sub _sigchld {
1197	# make sure we deliver these changes "synchronous" with the event loop.	1477	my $pid;
1198	$CHLD_DELAY_W \|\|= AnyEvent->timer (after => 0, cb => sub {	1478
1199	undef $CHLD_DELAY_W;	1479	AnyEvent->_emit_childstatus ($pid, $?)
1200	&_child_wait;	1480	while ($pid = waitpid -1, $WNOHANG) > 0;
1201	});
1202	}	1481	}
1203		1482
1204	sub child {	1483	sub child {
1205	my (undef, %arg) = @_;	1484	my (undef, %arg) = @_;
1206		1485
1207	defined (my $pid = $arg{pid} + 0)	1486	defined (my $pid = $arg{pid} + 0)
1208	or Carp::croak "required option 'pid' is missing";	1487	or Carp::croak "required option 'pid' is missing";
1209		1488
1210	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1489	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1211		1490
1212	unless ($WNOHANG) {	1491	# WNOHANG is almost cetrainly 1 everywhere
		1492	$WNOHANG \|\|= $^O =~ /^(?:openbsd\|netbsd\|linux\|freebsd\|cygwin\|MSWin32)$/
		1493	? 1
1213	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;	1494	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
1214	}
1215		1495
1216	unless ($CHLD_W) {	1496	unless ($CHLD_W) {
1217	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1497	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1218	# child could be a zombie already, so make at least one round	1498	# child could be a zombie already, so make at least one round
1219	&_sigchld;	1499	&_sigchld;
…		…
1230		1510
1231	undef $CHLD_W unless keys %PID_CB;	1511	undef $CHLD_W unless keys %PID_CB;
1232	}	1512	}
1233		1513
1234	# idle emulation is done by simply using a timer, regardless	1514	# idle emulation is done by simply using a timer, regardless
1235	# of whether the proces sis idle or not, and not letting	1515	# of whether the process is idle or not, and not letting
1236	# the callback use more than 50% of the time.	1516	# the callback use more than 50% of the time.
1237	sub idle {	1517	sub idle {
1238	my (undef, %arg) = @_;	1518	my (undef, %arg) = @_;
1239		1519
1240	my ($cb, $w, $rcb) = $arg{cb};	1520	my ($cb, $w, $rcb) = $arg{cb};
…		…
1271		1551
1272	our @ISA = AnyEvent::CondVar::Base::;	1552	our @ISA = AnyEvent::CondVar::Base::;
1273		1553
1274	package AnyEvent::CondVar::Base;	1554	package AnyEvent::CondVar::Base;
1275		1555
1276	use overload	1556	#use overload
1277	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1557	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1278	fallback => 1;	1558	# fallback => 1;
		1559
		1560	# save 300+ kilobytes by dirtily hardcoding overloading
		1561	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1562	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1563	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1564	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1565
		1566	our $WAITING;
1279		1567
1280	sub _send {	1568	sub _send {
1281	# nop	1569	# nop
1282	}	1570	}
1283		1571
…		…
1296	sub ready {	1584	sub ready {
1297	$_[0]{_ae_sent}	1585	$_[0]{_ae_sent}
1298	}	1586	}
1299		1587
1300	sub _wait {	1588	sub _wait {
		1589	$WAITING
		1590	and !$_[0]{_ae_sent}
		1591	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1592
		1593	local $WAITING = 1;
1301	AnyEvent->one_event while !$_[0]{_ae_sent};	1594	AnyEvent->one_event while !$_[0]{_ae_sent};
1302	}	1595	}
1303		1596
1304	sub recv {	1597	sub recv {
1305	$_[0]->_wait;	1598	$_[0]->_wait;
…		…
1346	so on.	1639	so on.
1347		1640
1348	=head1 ENVIRONMENT VARIABLES	1641	=head1 ENVIRONMENT VARIABLES
1349		1642
1350	The following environment variables are used by this module or its	1643	The following environment variables are used by this module or its
1351	submodules:	1644	submodules.
		1645
		1646	Note that AnyEvent will remove I<all> environment variables starting with
		1647	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1648	enabled.
1352		1649
1353	=over 4	1650	=over 4
1354		1651
1355	=item C<PERL_ANYEVENT_VERBOSE>	1652	=item C<PERL_ANYEVENT_VERBOSE>
1356		1653
…		…
1363	C<PERL_ANYEVENT_MODEL>.	1660	C<PERL_ANYEVENT_MODEL>.
1364		1661
1365	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1662	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1366	model it chooses.	1663	model it chooses.
1367		1664
		1665	When set to C<8> or higher, then AnyEvent will report extra information on
		1666	which optional modules it loads and how it implements certain features.
		1667
1368	=item C<PERL_ANYEVENT_STRICT>	1668	=item C<PERL_ANYEVENT_STRICT>
1369		1669
1370	AnyEvent does not do much argument checking by default, as thorough	1670	AnyEvent does not do much argument checking by default, as thorough
1371	argument checking is very costly. Setting this variable to a true value	1671	argument checking is very costly. Setting this variable to a true value
1372	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1672	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1373	check the arguments passed to most method calls. If it finds any problems	1673	check the arguments passed to most method calls. If it finds any problems,
1374	it will croak.	1674	it will croak.
1375		1675
1376	In other words, enables "strict" mode.	1676	In other words, enables "strict" mode.
1377		1677
1378	Unlike C<use strict>, it is definitely recommended ot keep it off in	1678	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1379	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1679	>>, it is definitely recommended to keep it off in production. Keeping
1380	developing programs can be very useful, however.	1680	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1681	can be very useful, however.
1381		1682
1382	=item C<PERL_ANYEVENT_MODEL>	1683	=item C<PERL_ANYEVENT_MODEL>
1383		1684
1384	This can be used to specify the event model to be used by AnyEvent, before	1685	This can be used to specify the event model to be used by AnyEvent, before
1385	auto detection and -probing kicks in. It must be a string consisting	1686	auto detection and -probing kicks in. It must be a string consisting
…		…
1428		1729
1429	=item C<PERL_ANYEVENT_MAX_FORKS>	1730	=item C<PERL_ANYEVENT_MAX_FORKS>
1430		1731
1431	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1732	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1432	will create in parallel.	1733	will create in parallel.
		1734
		1735	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1736
		1737	The default value for the C<max_outstanding> parameter for the default DNS
		1738	resolver - this is the maximum number of parallel DNS requests that are
		1739	sent to the DNS server.
		1740
		1741	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1742
		1743	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1744	configuration) in the default resolver. When set to the empty string, no
		1745	default config will be used.
		1746
		1747	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1748
		1749	When neither C<ca_file> nor C<ca_path> was specified during
		1750	L<AnyEvent::TLS> context creation, and either of these environment
		1751	variables exist, they will be used to specify CA certificate locations
		1752	instead of a system-dependent default.
		1753
		1754	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1755
		1756	When these are set to C<1>, then the respective modules are not
		1757	loaded. Mostly good for testing AnyEvent itself.
1433		1758
1434	=back	1759	=back
1435		1760
1436	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1761	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1437		1762
…		…
1682	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2007	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1683	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2008	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1684	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2009	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1685	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2010	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1686	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2011	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		2012	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		2013	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1687	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2014	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1688	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2015	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1689	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2016	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1690	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2017	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1691		2018
…		…
1720	performance becomes really bad with lots of file descriptors (and few of	2047	performance becomes really bad with lots of file descriptors (and few of
1721	them active), of course, but this was not subject of this benchmark.	2048	them active), of course, but this was not subject of this benchmark.
1722		2049
1723	The C<Event> module has a relatively high setup and callback invocation	2050	The C<Event> module has a relatively high setup and callback invocation
1724	cost, but overall scores in on the third place.	2051	cost, but overall scores in on the third place.
		2052
		2053	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2054	when using its pure perl backend.
1725		2055
1726	C<Glib>'s memory usage is quite a bit higher, but it features a	2056	C<Glib>'s memory usage is quite a bit higher, but it features a
1727	faster callback invocation and overall ends up in the same class as	2057	faster callback invocation and overall ends up in the same class as
1728	C<Event>. However, Glib scales extremely badly, doubling the number of	2058	C<Event>. However, Glib scales extremely badly, doubling the number of
1729	watchers increases the processing time by more than a factor of four,	2059	watchers increases the processing time by more than a factor of four,
…		…
1807	it to another server. This includes deleting the old timeout and creating	2137	it to another server. This includes deleting the old timeout and creating
1808	a new one that moves the timeout into the future.	2138	a new one that moves the timeout into the future.
1809		2139
1810	=head3 Results	2140	=head3 Results
1811		2141
1812	name sockets create request	2142	name sockets create request
1813	EV 20000 69.01 11.16	2143	EV 20000 69.01 11.16
1814	Perl 20000 73.32 35.87	2144	Perl 20000 73.32 35.87
		2145	IOAsync 20000 157.00 98.14 epoll
		2146	IOAsync 20000 159.31 616.06 poll
1815	Event 20000 212.62 257.32	2147	Event 20000 212.62 257.32
1816	Glib 20000 651.16 1896.30	2148	Glib 20000 651.16 1896.30
1817	POE 20000 349.67 12317.24 uses POE::Loop::Event	2149	POE 20000 349.67 12317.24 uses POE::Loop::Event
1818		2150
1819	=head3 Discussion	2151	=head3 Discussion
1820		2152
1821	This benchmark I<does> measure scalability and overall performance of the	2153	This benchmark I<does> measure scalability and overall performance of the
1822	particular event loop.	2154	particular event loop.
…		…
1824	EV is again fastest. Since it is using epoll on my system, the setup time	2156	EV is again fastest. Since it is using epoll on my system, the setup time
1825	is relatively high, though.	2157	is relatively high, though.
1826		2158
1827	Perl surprisingly comes second. It is much faster than the C-based event	2159	Perl surprisingly comes second. It is much faster than the C-based event
1828	loops Event and Glib.	2160	loops Event and Glib.
		2161
		2162	IO::Async performs very well when using its epoll backend, and still quite
		2163	good compared to Glib when using its pure perl backend.
1829		2164
1830	Event suffers from high setup time as well (look at its code and you will	2165	Event suffers from high setup time as well (look at its code and you will
1831	understand why). Callback invocation also has a high overhead compared to	2166	understand why). Callback invocation also has a high overhead compared to
1832	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2167	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1833	uses select or poll in basically all documented configurations.	2168	uses select or poll in basically all documented configurations.
…		…
1896	=item * C-based event loops perform very well with small number of	2231	=item * C-based event loops perform very well with small number of
1897	watchers, as the management overhead dominates.	2232	watchers, as the management overhead dominates.
1898		2233
1899	=back	2234	=back
1900		2235
		2236	=head2 THE IO::Lambda BENCHMARK
		2237
		2238	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2239	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2240	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2241	shouldn't come as a surprise to anybody). As such, the benchmark is
		2242	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2243	very optimal. But how would AnyEvent compare when used without the extra
		2244	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2245
		2246	The benchmark itself creates an echo-server, and then, for 500 times,
		2247	connects to the echo server, sends a line, waits for the reply, and then
		2248	creates the next connection. This is a rather bad benchmark, as it doesn't
		2249	test the efficiency of the framework or much non-blocking I/O, but it is a
		2250	benchmark nevertheless.
		2251
		2252	name runtime
		2253	Lambda/select 0.330 sec
		2254	+ optimized 0.122 sec
		2255	Lambda/AnyEvent 0.327 sec
		2256	+ optimized 0.138 sec
		2257	Raw sockets/select 0.077 sec
		2258	POE/select, components 0.662 sec
		2259	POE/select, raw sockets 0.226 sec
		2260	POE/select, optimized 0.404 sec
		2261
		2262	AnyEvent/select/nb 0.085 sec
		2263	AnyEvent/EV/nb 0.068 sec
		2264	+state machine 0.134 sec
		2265
		2266	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2267	benchmarks actually make blocking connects and use 100% blocking I/O,
		2268	defeating the purpose of an event-based solution. All of the newly
		2269	written AnyEvent benchmarks use 100% non-blocking connects (using
		2270	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2271	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2272	generally require a lot more bookkeeping and event handling than blocking
		2273	connects (which involve a single syscall only).
		2274
		2275	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2276	offers similar expressive power as POE and IO::Lambda, using conventional
		2277	Perl syntax. This means that both the echo server and the client are 100%
		2278	non-blocking, further placing it at a disadvantage.
		2279
		2280	As you can see, the AnyEvent + EV combination even beats the
		2281	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2282	backend easily beats IO::Lambda and POE.
		2283
		2284	And even the 100% non-blocking version written using the high-level (and
		2285	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2286	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2287	in a non-blocking way.
		2288
		2289	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2290	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2291	part of the IO::lambda distribution and were used without any changes.
		2292
1901		2293
1902	=head1 SIGNALS	2294	=head1 SIGNALS
1903		2295
1904	AnyEvent currently installs handlers for these signals:	2296	AnyEvent currently installs handlers for these signals:
1905		2297
…		…
1908	=item SIGCHLD	2300	=item SIGCHLD
1909		2301
1910	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2302	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1911	emulation for event loops that do not support them natively. Also, some	2303	emulation for event loops that do not support them natively. Also, some
1912	event loops install a similar handler.	2304	event loops install a similar handler.
		2305
		2306	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2307	AnyEvent will reset it to default, to avoid losing child exit statuses.
1913		2308
1914	=item SIGPIPE	2309	=item SIGPIPE
1915		2310
1916	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2311	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1917	when AnyEvent gets loaded.	2312	when AnyEvent gets loaded.
…		…
1929		2324
1930	=back	2325	=back
1931		2326
1932	=cut	2327	=cut
1933		2328
		2329	undef $SIG{CHLD}
		2330	if $SIG{CHLD} eq 'IGNORE';
		2331
1934	$SIG{PIPE} = sub { }	2332	$SIG{PIPE} = sub { }
1935	unless defined $SIG{PIPE};	2333	unless defined $SIG{PIPE};
		2334
		2335	=head1 RECOMMENDED/OPTIONAL MODULES
		2336
		2337	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2338	it's built-in modules) are required to use it.
		2339
		2340	That does not mean that AnyEvent won't take advantage of some additional
		2341	modules if they are installed.
		2342
		2343	This section epxlains which additional modules will be used, and how they
		2344	affect AnyEvent's operetion.
		2345
		2346	=over 4
		2347
		2348	=item L<Async::Interrupt>
		2349
		2350	This slightly arcane module is used to implement fast signal handling: To
		2351	my knowledge, there is no way to do completely race-free and quick
		2352	signal handling in pure perl. To ensure that signals still get
		2353	delivered, AnyEvent will start an interval timer to wake up perl (and
		2354	catch the signals) with some delay (default is 10 seconds, look for
		2355	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2356
		2357	If this module is available, then it will be used to implement signal
		2358	catching, which means that signals will not be delayed, and the event loop
		2359	will not be interrupted regularly, which is more efficient (And good for
		2360	battery life on laptops).
		2361
		2362	This affects not just the pure-perl event loop, but also other event loops
		2363	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2364
		2365	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2366	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2367	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2368	does nothing for those backends.
		2369
		2370	=item L<EV>
		2371
		2372	This module isn't really "optional", as it is simply one of the backend
		2373	event loops that AnyEvent can use. However, it is simply the best event
		2374	loop available in terms of features, speed and stability: It supports
		2375	the AnyEvent API optimally, implements all the watcher types in XS, does
		2376	automatic timer adjustments even when no monotonic clock is available,
		2377	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2378	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2379	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2380
		2381	=item L<Guard>
		2382
		2383	The guard module, when used, will be used to implement
		2384	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2385	lot less memory), but otherwise doesn't affect guard operation much. It is
		2386	purely used for performance.
		2387
		2388	=item L<JSON> and L<JSON::XS>
		2389
		2390	This module is required when you want to read or write JSON data via
		2391	L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2392	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2393
		2394	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2395	installed.
		2396
		2397	=item L<Net::SSLeay>
		2398
		2399	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2400	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2401	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2402
		2403	=item L<Time::HiRes>
		2404
		2405	This module is part of perl since release 5.008. It will be used when the
		2406	chosen event library does not come with a timing source on it's own. The
		2407	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2408	try to use a monotonic clock for timing stability.
		2409
		2410	=back
1936		2411
1937		2412
1938	=head1 FORK	2413	=head1 FORK
1939		2414
1940	Most event libraries are not fork-safe. The ones who are usually are	2415	Most event libraries are not fork-safe. The ones who are usually are
1941	because they rely on inefficient but fork-safe C<select> or C<poll>	2416	because they rely on inefficient but fork-safe C<select> or C<poll>
1942	calls. Only L<EV> is fully fork-aware.	2417	calls. Only L<EV> is fully fork-aware.
1943		2418
1944	If you have to fork, you must either do so I<before> creating your first	2419	If you have to fork, you must either do so I<before> creating your first
1945	watcher OR you must not use AnyEvent at all in the child.	2420	watcher OR you must not use AnyEvent at all in the child OR you must do
		2421	something completely out of the scope of AnyEvent.
1946		2422
1947		2423
1948	=head1 SECURITY CONSIDERATIONS	2424	=head1 SECURITY CONSIDERATIONS
1949		2425
1950	AnyEvent can be forced to load any event model via	2426	AnyEvent can be forced to load any event model via
…		…
1962	use AnyEvent;	2438	use AnyEvent;
1963		2439
1964	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2440	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1965	be used to probe what backend is used and gain other information (which is	2441	be used to probe what backend is used and gain other information (which is
1966	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2442	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1967	$ENV{PERL_ANYEGENT_STRICT}.	2443	$ENV{PERL_ANYEVENT_STRICT}.
		2444
		2445	Note that AnyEvent will remove I<all> environment variables starting with
		2446	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2447	enabled.
1968		2448
1969		2449
1970	=head1 BUGS	2450	=head1 BUGS
1971		2451
1972	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2452	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
…		…
1984	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2464	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1985		2465
1986	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2466	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1987	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2467	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1988	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2468	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1989	L<AnyEvent::Impl::POE>.	2469	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1990		2470
1991	Non-blocking file handles, sockets, TCP clients and	2471	Non-blocking file handles, sockets, TCP clients and
1992	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2472	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1993		2473
1994	Asynchronous DNS: L<AnyEvent::DNS>.	2474	Asynchronous DNS: L<AnyEvent::DNS>.
1995		2475
1996	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2476	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2477	L<Coro::Event>,
1997		2478
1998	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2479	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2480	L<AnyEvent::HTTP>.
1999		2481
2000		2482
2001	=head1 AUTHOR	2483	=head1 AUTHOR
2002		2484
2003	Marc Lehmann <schmorp@schmorp.de>	2485	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.208 by root, Sun Apr 26 18:12:53 2009 UTC vs. Revision 1.263 by root, Wed Jul 29 12:39:21 2009 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.208 by root, Sun Apr 26 18:12:53 2009 UTC vs.
Revision 1.263 by root, Wed Jul 29 12:39:21 2009 UTC