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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.205 by root, Sun Apr 19 12:09:46 2009 UTC vs.
Revision 1.246 by root, Sat Jul 18 15:51:52 2009 UTC

…		…
1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - provide framework for multiple event loops
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported
		6	event loops.
6		7
7	=head1 SYNOPSIS	8	=head1 SYNOPSIS
8		9
9	use AnyEvent;	10	use AnyEvent;
10		11
		12	# file descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub { ... });	13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
12		14
		15	# one-shot or repeating timers
13	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
14	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
15		18
16	print AnyEvent->now; # prints current event loop time	19	print AnyEvent->now; # prints current event loop time
17	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
18		21
		22	# POSIX signal
19	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });	23	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
20		24
		25	# child process exit
21	my $w = AnyEvent->child (pid => $pid, cb => sub {	26	my $w = AnyEvent->child (pid => $pid, cb => sub {
22	my ($pid, $status) = @_;	27	my ($pid, $status) = @_;
23	...	28	...
24	});	29	});
		30
		31	# called when event loop idle (if applicable)
		32	my $w = AnyEvent->idle (cb => sub { ... });
25		33
26	my $w = AnyEvent->condvar; # stores whether a condition was flagged	34	my $w = AnyEvent->condvar; # stores whether a condition was flagged
27	$w->send; # wake up current and all future recv's	35	$w->send; # wake up current and all future recv's
28	$w->recv; # enters "main loop" till $condvar gets ->send	36	$w->recv; # enters "main loop" till $condvar gets ->send
29	# use a condvar in callback mode:	37	# use a condvar in callback mode:
168	=head2 I/O WATCHERS	176	=head2 I/O WATCHERS
169		177
170	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
171	with the following mandatory key-value pairs as arguments:	179	with the following mandatory key-value pairs as arguments:
172		180
173	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch	181	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
174	for events (AnyEvent might or might not keep a reference to this file	182	for events (AnyEvent might or might not keep a reference to this file
175	handle). Note that only file handles pointing to things for which	183	handle). Note that only file handles pointing to things for which
176	non-blocking operation makes sense are allowed. This includes sockets,	184	non-blocking operation makes sense are allowed. This includes sockets,
177	most character devices, pipes, fifos and so on, but not for example files	185	most character devices, pipes, fifos and so on, but not for example files
178	or block devices.	186	or block devices.
…		…
353	invocation, and callback invocation will be synchronous. Synchronous means	361	invocation, and callback invocation will be synchronous. Synchronous means
354	that it might take a while until the signal gets handled by the process,	362	that it might take a while until the signal gets handled by the process,
355	but it is guaranteed not to interrupt any other callbacks.	363	but it is guaranteed not to interrupt any other callbacks.
356		364
357	The main advantage of using these watchers is that you can share a signal	365	The main advantage of using these watchers is that you can share a signal
358	between multiple watchers.	366	between multiple watchers, and AnyEvent will ensure that signals will not
		367	interrupt your program at bad times.
359		368
360	This watcher might use C<%SIG>, so programs overwriting those signals	369	This watcher might use C<%SIG> (depending on the event loop used),
361	directly will likely not work correctly.	370	so programs overwriting those signals directly will likely not work
		371	correctly.
		372
		373	Also note that many event loops (e.g. Glib, Tk, Qt, IO::Async) do not
		374	support attaching callbacks to signals, which is a pity, as you cannot do
		375	race-free signal handling in perl. AnyEvent will try to do it's best, but
		376	in some cases, signals will be delayed. The maximum time a signal might
		377	be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10
		378	seconds). This variable can be changed only before the first signal
		379	watcher is created, and should be left alone otherwise. Higher values
		380	will cause fewer spurious wake-ups, which is better for power and CPU
		381	saving. All these problems can be avoided by installing the optional
		382	L<Async::Interrupt> module.
362		383
363	Example: exit on SIGINT	384	Example: exit on SIGINT
364		385
365	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	386	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
366		387
…		…
384		405
385	There is a slight catch to child watchers, however: you usually start them	406	There is a slight catch to child watchers, however: you usually start them
386	I<after> the child process was created, and this means the process could	407	I<after> the child process was created, and this means the process could
387	have exited already (and no SIGCHLD will be sent anymore).	408	have exited already (and no SIGCHLD will be sent anymore).
388		409
389	Not all event models handle this correctly (POE doesn't), but even for	410	Not all event models handle this correctly (neither POE nor IO::Async do,
		411	see their AnyEvent::Impl manpages for details), but even for event models
390	event models that I<do> handle this correctly, they usually need to be	412	that I<do> handle this correctly, they usually need to be loaded before
391	loaded before the process exits (i.e. before you fork in the first place).	413	the process exits (i.e. before you fork in the first place). AnyEvent's
		414	pure perl event loop handles all cases correctly regardless of when you
		415	start the watcher.
392		416
393	This means you cannot create a child watcher as the very first thing in an	417	This means you cannot create a child watcher as the very first
394	AnyEvent program, you I<have> to create at least one watcher before you	418	thing in an AnyEvent program, you I<have> to create at least one
395	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	419	watcher before you C<fork> the child (alternatively, you can call
		420	C<AnyEvent::detect>).
		421
		422	As most event loops do not support waiting for child events, they will be
		423	emulated by AnyEvent in most cases, in which the latency and race problems
		424	mentioned in the description of signal watchers apply.
396		425
397	Example: fork a process and wait for it	426	Example: fork a process and wait for it
398		427
399	my $done = AnyEvent->condvar;	428	my $done = AnyEvent->condvar;
400		429
…		…
410	);	439	);
411		440
412	# do something else, then wait for process exit	441	# do something else, then wait for process exit
413	$done->recv;	442	$done->recv;
414		443
		444	=head2 IDLE WATCHERS
		445
		446	Sometimes there is a need to do something, but it is not so important
		447	to do it instantly, but only when there is nothing better to do. This
		448	"nothing better to do" is usually defined to be "no other events need
		449	attention by the event loop".
		450
		451	Idle watchers ideally get invoked when the event loop has nothing
		452	better to do, just before it would block the process to wait for new
		453	events. Instead of blocking, the idle watcher is invoked.
		454
		455	Most event loops unfortunately do not really support idle watchers (only
		456	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		457	will simply call the callback "from time to time".
		458
		459	Example: read lines from STDIN, but only process them when the
		460	program is otherwise idle:
		461
		462	my @lines; # read data
		463	my $idle_w;
		464	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		465	push @lines, scalar <STDIN>;
		466
		467	# start an idle watcher, if not already done
		468	$idle_w \|\|= AnyEvent->idle (cb => sub {
		469	# handle only one line, when there are lines left
		470	if (my $line = shift @lines) {
		471	print "handled when idle: $line";
		472	} else {
		473	# otherwise disable the idle watcher again
		474	undef $idle_w;
		475	}
		476	});
		477	});
		478
415	=head2 CONDITION VARIABLES	479	=head2 CONDITION VARIABLES
416		480
417	If you are familiar with some event loops you will know that all of them	481	If you are familiar with some event loops you will know that all of them
418	require you to run some blocking "loop", "run" or similar function that	482	require you to run some blocking "loop", "run" or similar function that
419	will actively watch for new events and call your callbacks.	483	will actively watch for new events and call your callbacks.
420		484
421	AnyEvent is different, it expects somebody else to run the event loop and	485	AnyEvent is slightly different: it expects somebody else to run the event
422	will only block when necessary (usually when told by the user).	486	loop and will only block when necessary (usually when told by the user).
423		487
424	The instrument to do that is called a "condition variable", so called	488	The instrument to do that is called a "condition variable", so called
425	because they represent a condition that must become true.	489	because they represent a condition that must become true.
426		490
		491	Now is probably a good time to look at the examples further below.
		492
427	Condition variables can be created by calling the C<< AnyEvent->condvar	493	Condition variables can be created by calling the C<< AnyEvent->condvar
428	>> method, usually without arguments. The only argument pair allowed is	494	>> method, usually without arguments. The only argument pair allowed is
429
430	C<cb>, which specifies a callback to be called when the condition variable	495	C<cb>, which specifies a callback to be called when the condition variable
431	becomes true, with the condition variable as the first argument (but not	496	becomes true, with the condition variable as the first argument (but not
432	the results).	497	the results).
433		498
434	After creation, the condition variable is "false" until it becomes "true"	499	After creation, the condition variable is "false" until it becomes "true"
…		…
483	after => 1,	548	after => 1,
484	cb => sub { $result_ready->send },	549	cb => sub { $result_ready->send },
485	);	550	);
486		551
487	# this "blocks" (while handling events) till the callback	552	# this "blocks" (while handling events) till the callback
488	# calls send	553	# calls -<send
489	$result_ready->recv;	554	$result_ready->recv;
490		555
491	Example: wait for a timer, but take advantage of the fact that	556	Example: wait for a timer, but take advantage of the fact that condition
492	condition variables are also code references.	557	variables are also callable directly.
493		558
494	my $done = AnyEvent->condvar;	559	my $done = AnyEvent->condvar;
495	my $delay = AnyEvent->timer (after => 5, cb => $done);	560	my $delay = AnyEvent->timer (after => 5, cb => $done);
496	$done->recv;	561	$done->recv;
497		562
…		…
503		568
504	...	569	...
505		570
506	my @info = $couchdb->info->recv;	571	my @info = $couchdb->info->recv;
507		572
508	And this is how you would just ste a callback to be called whenever the	573	And this is how you would just set a callback to be called whenever the
509	results are available:	574	results are available:
510		575
511	$couchdb->info->cb (sub {	576	$couchdb->info->cb (sub {
512	my @info = $_[0]->recv;	577	my @info = $_[0]->recv;
513	});	578	});
…		…
531	immediately from within send.	596	immediately from within send.
532		597
533	Any arguments passed to the C<send> call will be returned by all	598	Any arguments passed to the C<send> call will be returned by all
534	future C<< ->recv >> calls.	599	future C<< ->recv >> calls.
535		600
536	Condition variables are overloaded so one can call them directly	601	Condition variables are overloaded so one can call them directly (as if
537	(as a code reference). Calling them directly is the same as calling	602	they were a code reference). Calling them directly is the same as calling
538	C<send>. Note, however, that many C-based event loops do not handle	603	C<send>.
539	overloading, so as tempting as it may be, passing a condition variable
540	instead of a callback does not work. Both the pure perl and EV loops
541	support overloading, however, as well as all functions that use perl to
542	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
543	example).
544		604
545	=item $cv->croak ($error)	605	=item $cv->croak ($error)
546		606
547	Similar to send, but causes all call's to C<< ->recv >> to invoke	607	Similar to send, but causes all call's to C<< ->recv >> to invoke
548	C<Carp::croak> with the given error message/object/scalar.	608	C<Carp::croak> with the given error message/object/scalar.
549		609
550	This can be used to signal any errors to the condition variable	610	This can be used to signal any errors to the condition variable
551	user/consumer.	611	user/consumer. Doing it this way instead of calling C<croak> directly
		612	delays the error detetcion, but has the overwhelmign advantage that it
		613	diagnoses the error at the place where the result is expected, and not
		614	deep in some event clalback without connection to the actual code causing
		615	the problem.
552		616
553	=item $cv->begin ([group callback])	617	=item $cv->begin ([group callback])
554		618
555	=item $cv->end	619	=item $cv->end
556
557	These two methods are EXPERIMENTAL and MIGHT CHANGE.
558		620
559	These two methods can be used to combine many transactions/events into	621	These two methods can be used to combine many transactions/events into
560	one. For example, a function that pings many hosts in parallel might want	622	one. For example, a function that pings many hosts in parallel might want
561	to use a condition variable for the whole process.	623	to use a condition variable for the whole process.
562		624
…		…
564	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	626	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
565	>>, the (last) callback passed to C<begin> will be executed. That callback	627	>>, the (last) callback passed to C<begin> will be executed. That callback
566	is I<supposed> to call C<< ->send >>, but that is not required. If no	628	is I<supposed> to call C<< ->send >>, but that is not required. If no
567	callback was set, C<send> will be called without any arguments.	629	callback was set, C<send> will be called without any arguments.
568		630
569	Let's clarify this with the ping example:	631	You can think of C<< $cv->send >> giving you an OR condition (one call
		632	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		633	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		634
		635	Let's start with a simple example: you have two I/O watchers (for example,
		636	STDOUT and STDERR for a program), and you want to wait for both streams to
		637	close before activating a condvar:
		638
		639	my $cv = AnyEvent->condvar;
		640
		641	$cv->begin; # first watcher
		642	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		643	defined sysread $fh1, my $buf, 4096
		644	or $cv->end;
		645	});
		646
		647	$cv->begin; # second watcher
		648	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		649	defined sysread $fh2, my $buf, 4096
		650	or $cv->end;
		651	});
		652
		653	$cv->recv;
		654
		655	This works because for every event source (EOF on file handle), there is
		656	one call to C<begin>, so the condvar waits for all calls to C<end> before
		657	sending.
		658
		659	The ping example mentioned above is slightly more complicated, as the
		660	there are results to be passwd back, and the number of tasks that are
		661	begung can potentially be zero:
570		662
571	my $cv = AnyEvent->condvar;	663	my $cv = AnyEvent->condvar;
572		664
573	my %result;	665	my %result;
574	$cv->begin (sub { $cv->send (\%result) });	666	$cv->begin (sub { $cv->send (\%result) });
…		…
594	loop, which serves two important purposes: first, it sets the callback	686	loop, which serves two important purposes: first, it sets the callback
595	to be called once the counter reaches C<0>, and second, it ensures that	687	to be called once the counter reaches C<0>, and second, it ensures that
596	C<send> is called even when C<no> hosts are being pinged (the loop	688	C<send> is called even when C<no> hosts are being pinged (the loop
597	doesn't execute once).	689	doesn't execute once).
598		690
599	This is the general pattern when you "fan out" into multiple subrequests:	691	This is the general pattern when you "fan out" into multiple (but
600	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	692	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
601	is called at least once, and then, for each subrequest you start, call	693	the callback and ensure C<end> is called at least once, and then, for each
602	C<begin> and for each subrequest you finish, call C<end>.	694	subrequest you start, call C<begin> and for each subrequest you finish,
		695	call C<end>.
603		696
604	=back	697	=back
605		698
606	=head3 METHODS FOR CONSUMERS	699	=head3 METHODS FOR CONSUMERS
607		700
…		…
623	function will call C<croak>.	716	function will call C<croak>.
624		717
625	In list context, all parameters passed to C<send> will be returned,	718	In list context, all parameters passed to C<send> will be returned,
626	in scalar context only the first one will be returned.	719	in scalar context only the first one will be returned.
627		720
		721	Note that doing a blocking wait in a callback is not supported by any
		722	event loop, that is, recursive invocation of a blocking C<< ->recv
		723	>> is not allowed, and the C<recv> call will C<croak> if such a
		724	condition is detected. This condition can be slightly loosened by using
		725	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		726	any thread that doesn't run the event loop itself.
		727
628	Not all event models support a blocking wait - some die in that case	728	Not all event models support a blocking wait - some die in that case
629	(programs might want to do that to stay interactive), so I<if you are	729	(programs might want to do that to stay interactive), so I<if you are
630	using this from a module, never require a blocking wait>, but let the	730	using this from a module, never require a blocking wait>. Instead, let the
631	caller decide whether the call will block or not (for example, by coupling	731	caller decide whether the call will block or not (for example, by coupling
632	condition variables with some kind of request results and supporting	732	condition variables with some kind of request results and supporting
633	callbacks so the caller knows that getting the result will not block,	733	callbacks so the caller knows that getting the result will not block,
634	while still supporting blocking waits if the caller so desires).	734	while still supporting blocking waits if the caller so desires).
635		735
636	Another reason I<never> to C<< ->recv >> in a module is that you cannot
637	sensibly have two C<< ->recv >>'s in parallel, as that would require
638	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
639	can supply.
640
641	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
642	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
643	versions and also integrates coroutines into AnyEvent, making blocking
644	C<< ->recv >> calls perfectly safe as long as they are done from another
645	coroutine (one that doesn't run the event loop).
646
647	You can ensure that C<< -recv >> never blocks by setting a callback and	736	You can ensure that C<< -recv >> never blocks by setting a callback and
648	only calling C<< ->recv >> from within that callback (or at a later	737	only calling C<< ->recv >> from within that callback (or at a later
649	time). This will work even when the event loop does not support blocking	738	time). This will work even when the event loop does not support blocking
650	waits otherwise.	739	waits otherwise.
651		740
…		…
664	variable itself. Calling C<recv> inside the callback or at any later time	753	variable itself. Calling C<recv> inside the callback or at any later time
665	is guaranteed not to block.	754	is guaranteed not to block.
666		755
667	=back	756	=back
668		757
		758	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		759
		760	The available backend classes are (every class has its own manpage):
		761
		762	=over 4
		763
		764	=item Backends that are autoprobed when no other event loop can be found.
		765
		766	EV is the preferred backend when no other event loop seems to be in
		767	use. If EV is not installed, then AnyEvent will try Event, and, failing
		768	that, will fall back to its own pure-perl implementation, which is
		769	available everywhere as it comes with AnyEvent itself.
		770
		771	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		772	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		773	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		774
		775	=item Backends that are transparently being picked up when they are used.
		776
		777	These will be used when they are currently loaded when the first watcher
		778	is created, in which case it is assumed that the application is using
		779	them. This means that AnyEvent will automatically pick the right backend
		780	when the main program loads an event module before anything starts to
		781	create watchers. Nothing special needs to be done by the main program.
		782
		783	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		784	AnyEvent::Impl::Tk based on Tk, very broken.
		785	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		786	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		787
		788	=item Backends with special needs.
		789
		790	Qt requires the Qt::Application to be instantiated first, but will
		791	otherwise be picked up automatically. As long as the main program
		792	instantiates the application before any AnyEvent watchers are created,
		793	everything should just work.
		794
		795	AnyEvent::Impl::Qt based on Qt.
		796
		797	Support for IO::Async can only be partial, as it is too broken and
		798	architecturally limited to even support the AnyEvent API. It also
		799	is the only event loop that needs the loop to be set explicitly, so
		800	it can only be used by a main program knowing about AnyEvent. See
		801	L<AnyEvent::Impl::Async> for the gory details.
		802
		803	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		804
		805	=item Event loops that are indirectly supported via other backends.
		806
		807	Some event loops can be supported via other modules:
		808
		809	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		810
		811	B<WxWidgets> has no support for watching file handles. However, you can
		812	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		813	polls 20 times per second, which was considered to be too horrible to even
		814	consider for AnyEvent.
		815
		816	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		817	backend, so it can be supported through POE.
		818
		819	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		820	load L<POE> when detecting them, in the hope that POE will pick them up,
		821	in which case everything will be automatic.
		822
		823	=back
		824
669	=head1 GLOBAL VARIABLES AND FUNCTIONS	825	=head1 GLOBAL VARIABLES AND FUNCTIONS
670		826
		827	These are not normally required to use AnyEvent, but can be useful to
		828	write AnyEvent extension modules.
		829
671	=over 4	830	=over 4
672		831
673	=item $AnyEvent::MODEL	832	=item $AnyEvent::MODEL
674		833
675	Contains C<undef> until the first watcher is being created. Then it	834	Contains C<undef> until the first watcher is being created, before the
		835	backend has been autodetected.
		836
676	contains the event model that is being used, which is the name of the	837	Afterwards it contains the event model that is being used, which is the
677	Perl class implementing the model. This class is usually one of the	838	name of the Perl class implementing the model. This class is usually one
678	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	839	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
679	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	840	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
680		841	will be C<urxvt::anyevent>).
681	The known classes so far are:
682
683	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
684	AnyEvent::Impl::Event based on Event, second best choice.
685	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
686	AnyEvent::Impl::Glib based on Glib, third-best choice.
687	AnyEvent::Impl::Tk based on Tk, very bad choice.
688	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
689	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
690	AnyEvent::Impl::POE based on POE, not generic enough for full support.
691
692	There is no support for WxWidgets, as WxWidgets has no support for
693	watching file handles. However, you can use WxWidgets through the
694	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
695	second, which was considered to be too horrible to even consider for
696	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
697	it's adaptor.
698
699	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
700	autodetecting them.
701		842
702	=item AnyEvent::detect	843	=item AnyEvent::detect
703		844
704	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	845	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
705	if necessary. You should only call this function right before you would	846	if necessary. You should only call this function right before you would
706	have created an AnyEvent watcher anyway, that is, as late as possible at	847	have created an AnyEvent watcher anyway, that is, as late as possible at
707	runtime.	848	runtime, and not e.g. while initialising of your module.
		849
		850	If you need to do some initialisation before AnyEvent watchers are
		851	created, use C<post_detect>.
708		852
709	=item $guard = AnyEvent::post_detect { BLOCK }	853	=item $guard = AnyEvent::post_detect { BLOCK }
710		854
711	Arranges for the code block to be executed as soon as the event model is	855	Arranges for the code block to be executed as soon as the event model is
712	autodetected (or immediately if this has already happened).	856	autodetected (or immediately if this has already happened).
		857
		858	The block will be executed I<after> the actual backend has been detected
		859	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		860	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		861	other initialisations - see the sources of L<AnyEvent::Strict> or
		862	L<AnyEvent::AIO> to see how this is used.
		863
		864	The most common usage is to create some global watchers, without forcing
		865	event module detection too early, for example, L<AnyEvent::AIO> creates
		866	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		867	avoid autodetecting the event module at load time.
713		868
714	If called in scalar or list context, then it creates and returns an object	869	If called in scalar or list context, then it creates and returns an object
715	that automatically removes the callback again when it is destroyed. See	870	that automatically removes the callback again when it is destroyed. See
716	L<Coro::BDB> for a case where this is useful.	871	L<Coro::BDB> for a case where this is useful.
717		872
…		…
720	If there are any code references in this array (you can C<push> to it	875	If there are any code references in this array (you can C<push> to it
721	before or after loading AnyEvent), then they will called directly after	876	before or after loading AnyEvent), then they will called directly after
722	the event loop has been chosen.	877	the event loop has been chosen.
723		878
724	You should check C<$AnyEvent::MODEL> before adding to this array, though:	879	You should check C<$AnyEvent::MODEL> before adding to this array, though:
725	if it contains a true value then the event loop has already been detected,	880	if it is defined then the event loop has already been detected, and the
726	and the array will be ignored.	881	array will be ignored.
727		882
728	Best use C<AnyEvent::post_detect { BLOCK }> instead.	883	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		884	it,as it takes care of these details.
		885
		886	This variable is mainly useful for modules that can do something useful
		887	when AnyEvent is used and thus want to know when it is initialised, but do
		888	not need to even load it by default. This array provides the means to hook
		889	into AnyEvent passively, without loading it.
729		890
730	=back	891	=back
731		892
732	=head1 WHAT TO DO IN A MODULE	893	=head1 WHAT TO DO IN A MODULE
733		894
…		…
788		949
789		950
790	=head1 OTHER MODULES	951	=head1 OTHER MODULES
791		952
792	The following is a non-exhaustive list of additional modules that use	953	The following is a non-exhaustive list of additional modules that use
793	AnyEvent and can therefore be mixed easily with other AnyEvent modules	954	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
794	in the same program. Some of the modules come with AnyEvent, some are	955	modules and other event loops in the same program. Some of the modules
795	available via CPAN.	956	come with AnyEvent, most are available via CPAN.
796		957
797	=over 4	958	=over 4
798		959
799	=item L<AnyEvent::Util>	960	=item L<AnyEvent::Util>
800		961
…		…
809		970
810	=item L<AnyEvent::Handle>	971	=item L<AnyEvent::Handle>
811		972
812	Provide read and write buffers, manages watchers for reads and writes,	973	Provide read and write buffers, manages watchers for reads and writes,
813	supports raw and formatted I/O, I/O queued and fully transparent and	974	supports raw and formatted I/O, I/O queued and fully transparent and
814	non-blocking SSL/TLS.	975	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
815		976
816	=item L<AnyEvent::DNS>	977	=item L<AnyEvent::DNS>
817		978
818	Provides rich asynchronous DNS resolver capabilities.	979	Provides rich asynchronous DNS resolver capabilities.
819		980
…		…
847		1008
848	=item L<AnyEvent::GPSD>	1009	=item L<AnyEvent::GPSD>
849		1010
850	A non-blocking interface to gpsd, a daemon delivering GPS information.	1011	A non-blocking interface to gpsd, a daemon delivering GPS information.
851		1012
		1013	=item L<AnyEvent::IRC>
		1014
		1015	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1016
		1017	=item L<AnyEvent::XMPP>
		1018
		1019	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1020	Net::XMPP2>.
		1021
852	=item L<AnyEvent::IGS>	1022	=item L<AnyEvent::IGS>
853		1023
854	A non-blocking interface to the Internet Go Server protocol (used by	1024	A non-blocking interface to the Internet Go Server protocol (used by
855	L<App::IGS>).	1025	L<App::IGS>).
856		1026
857	=item L<AnyEvent::IRC>
858
859	AnyEvent based IRC client module family (replacing the older Net::IRC3).
860
861	=item L<Net::XMPP2>
862
863	AnyEvent based XMPP (Jabber protocol) module family.
864
865	=item L<Net::FCP>	1027	=item L<Net::FCP>
866		1028
867	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1029	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
868	of AnyEvent.	1030	of AnyEvent.
869		1031
…		…
873		1035
874	=item L<Coro>	1036	=item L<Coro>
875		1037
876	Has special support for AnyEvent via L<Coro::AnyEvent>.	1038	Has special support for AnyEvent via L<Coro::AnyEvent>.
877		1039
878	=item L<IO::Lambda>
879
880	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
881
882	=back	1040	=back
883		1041
884	=cut	1042	=cut
885		1043
886	package AnyEvent;	1044	package AnyEvent;
887		1045
		1046	# basically a tuned-down version of common::sense
		1047	sub common_sense {
888	no warnings;	1048	# no warnings
		1049	${^WARNING_BITS} ^= ${^WARNING_BITS};
889	use strict qw(vars subs);	1050	# use strict vars subs
		1051	$^H \|= 0x00000600;
		1052	}
890		1053
		1054	BEGIN { AnyEvent::common_sense }
		1055
891	use Carp;	1056	use Carp ();
892		1057
893	our $VERSION = 4.351;	1058	our $VERSION = 4.85;
894	our $MODEL;	1059	our $MODEL;
895		1060
896	our $AUTOLOAD;	1061	our $AUTOLOAD;
897	our @ISA;	1062	our @ISA;
898		1063
899	our @REGISTRY;	1064	our @REGISTRY;
900		1065
901	our $WIN32;	1066	our $WIN32;
902		1067
		1068	our $VERBOSE;
		1069
903	BEGIN {	1070	BEGIN {
904	my $win32 = ! ! ($^O =~ /mswin32/i);	1071	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
905	eval "sub WIN32(){ $win32 }";	1072	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
906	}
907		1073
		1074	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1075	if ${^TAINT};
		1076
908	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1077	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1078
		1079	}
		1080
		1081	our $MAX_SIGNAL_LATENCY = 10;
909		1082
910	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred	1083	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
911		1084
912	{	1085	{
913	my $idx;	1086	my $idx;
…		…
921	[Event:: => AnyEvent::Impl::Event::],	1094	[Event:: => AnyEvent::Impl::Event::],
922	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1095	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
923	# everything below here will not be autoprobed	1096	# everything below here will not be autoprobed
924	# as the pureperl backend should work everywhere	1097	# as the pureperl backend should work everywhere
925	# and is usually faster	1098	# and is usually faster
926	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
927	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1099	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
928	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1100	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1101	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
929	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1102	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
930	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1103	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
931	[Wx:: => AnyEvent::Impl::POE::],	1104	[Wx:: => AnyEvent::Impl::POE::],
932	[Prima:: => AnyEvent::Impl::POE::],	1105	[Prima:: => AnyEvent::Impl::POE::],
		1106	# IO::Async is just too broken - we would need workarounds for its
		1107	# byzantine signal and broken child handling, among others.
		1108	# IO::Async is rather hard to detect, as it doesn't have any
		1109	# obvious default class.
		1110	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1111	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1112	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
933	);	1113	);
934		1114
935	our %method = map +($_ => 1),	1115	our %method = map +($_ => 1),
936	qw(io timer time now now_update signal child condvar one_event DESTROY);	1116	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
937		1117
938	our @post_detect;	1118	our @post_detect;
939		1119
940	sub post_detect(&) {	1120	sub post_detect(&) {
941	my ($cb) = @_;	1121	my ($cb) = @_;
…		…
946	1	1126	1
947	} else {	1127	} else {
948	push @post_detect, $cb;	1128	push @post_detect, $cb;
949		1129
950	defined wantarray	1130	defined wantarray
951	? bless \$cb, "AnyEvent::Util::PostDetect"	1131	? bless \$cb, "AnyEvent::Util::postdetect"
952	: ()	1132	: ()
953	}	1133	}
954	}	1134	}
955		1135
956	sub AnyEvent::Util::PostDetect::DESTROY {	1136	sub AnyEvent::Util::postdetect::DESTROY {
957	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1137	@post_detect = grep $_ != ${$_[0]}, @post_detect;
958	}	1138	}
959		1139
960	sub detect() {	1140	sub detect() {
961	unless ($MODEL) {	1141	unless ($MODEL) {
962	no strict 'refs';
963	local $SIG{__DIE__};	1142	local $SIG{__DIE__};
964		1143
965	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1144	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
966	my $model = "AnyEvent::Impl::$1";	1145	my $model = "AnyEvent::Impl::$1";
967	if (eval "require $model") {	1146	if (eval "require $model") {
968	$MODEL = $model;	1147	$MODEL = $model;
969	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1148	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
970	} else {	1149	} else {
971	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1150	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
972	}	1151	}
973	}	1152	}
974		1153
975	# check for already loaded models	1154	# check for already loaded models
976	unless ($MODEL) {	1155	unless ($MODEL) {
977	for (@REGISTRY, @models) {	1156	for (@REGISTRY, @models) {
978	my ($package, $model) = @$_;	1157	my ($package, $model) = @$_;
979	if (${"$package\::VERSION"} > 0) {	1158	if (${"$package\::VERSION"} > 0) {
980	if (eval "require $model") {	1159	if (eval "require $model") {
981	$MODEL = $model;	1160	$MODEL = $model;
982	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1161	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
983	last;	1162	last;
984	}	1163	}
985	}	1164	}
986	}	1165	}
987		1166
…		…
992	my ($package, $model) = @$_;	1171	my ($package, $model) = @$_;
993	if (eval "require $package"	1172	if (eval "require $package"
994	and ${"$package\::VERSION"} > 0	1173	and ${"$package\::VERSION"} > 0
995	and eval "require $model") {	1174	and eval "require $model") {
996	$MODEL = $model;	1175	$MODEL = $model;
997	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1176	warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
998	last;	1177	last;
999	}	1178	}
1000	}	1179	}
1001		1180
1002	$MODEL	1181	$MODEL
…		…
1018		1197
1019	sub AUTOLOAD {	1198	sub AUTOLOAD {
1020	(my $func = $AUTOLOAD) =~ s/.*://;	1199	(my $func = $AUTOLOAD) =~ s/.*://;
1021		1200
1022	$method{$func}	1201	$method{$func}
1023	or croak "$func: not a valid method for AnyEvent objects";	1202	or Carp::croak "$func: not a valid method for AnyEvent objects";
1024		1203
1025	detect unless $MODEL;	1204	detect unless $MODEL;
1026		1205
1027	my $class = shift;	1206	my $class = shift;
1028	$class->$func (@_);	1207	$class->$func (@_);
1029	}	1208	}
1030		1209
1031	# utility function to dup a filehandle. this is used by many backends	1210	# utility function to dup a filehandle. this is used by many backends
1032	# to support binding more than one watcher per filehandle (they usually	1211	# to support binding more than one watcher per filehandle (they usually
1033	# allow only one watcher per fd, so we dup it to get a different one).	1212	# allow only one watcher per fd, so we dup it to get a different one).
1034	sub _dupfh($$$$) {	1213	sub _dupfh($$;$$) {
1035	my ($poll, $fh, $r, $w) = @_;	1214	my ($poll, $fh, $r, $w) = @_;
1036		1215
1037	# cygwin requires the fh mode to be matching, unix doesn't	1216	# cygwin requires the fh mode to be matching, unix doesn't
1038	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1217	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1039	: $poll eq "w" ? ($w, ">")
1040	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1041		1218
1042	open my $fh2, "$mode&" . fileno $fh	1219	open my $fh2, $mode, $fh
1043	or die "cannot dup() filehandle: $!,";	1220	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1044		1221
1045	# we assume CLOEXEC is already set by perl in all important cases	1222	# we assume CLOEXEC is already set by perl in all important cases
1046		1223
1047	($fh2, $rw)	1224	($fh2, $rw)
1048	}	1225	}
1049		1226
1050	package AnyEvent::Base;	1227	package AnyEvent::Base;
1051		1228
1052	# default implementations for many methods	1229	# default implementations for many methods
1053		1230
1054	BEGIN {	1231	sub _time {
		1232	# probe for availability of Time::HiRes
1055	if (eval "use Time::HiRes (); time (); 1") {	1233	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1234	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1056	*_time = \&Time::HiRes::time;	1235	*_time = \&Time::HiRes::time;
1057	# if (eval "use POSIX (); (POSIX::times())...	1236	# if (eval "use POSIX (); (POSIX::times())...
1058	} else {	1237	} else {
		1238	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1059	*_time = sub { time }; # epic fail	1239	*_time = sub { time }; # epic fail
1060	}	1240	}
		1241
		1242	&_time
1061	}	1243	}
1062		1244
1063	sub time { _time }	1245	sub time { _time }
1064	sub now { _time }	1246	sub now { _time }
1065	sub now_update { }	1247	sub now_update { }
1066		1248
1067	# default implementation for ->condvar	1249	# default implementation for ->condvar
1068		1250
1069	sub condvar {	1251	sub condvar {
1070	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1252	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1071	}	1253	}
1072		1254
1073	# default implementation for ->signal	1255	# default implementation for ->signal
1074		1256
		1257	our $HAVE_ASYNC_INTERRUPT;
1075	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1258	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1259	our (%SIG_ASY, %SIG_ASY_W);
		1260	our ($SIG_COUNT, $SIG_TW);
1076		1261
1077	sub _signal_exec {	1262	sub _signal_exec {
		1263	$HAVE_ASYNC_INTERRUPT
		1264	? $SIGPIPE_R->drain
1078	sysread $SIGPIPE_R, my $dummy, 4;	1265	: sysread $SIGPIPE_R, my $dummy, 9;
1079		1266
1080	while (%SIG_EV) {	1267	while (%SIG_EV) {
1081	for (keys %SIG_EV) {	1268	for (keys %SIG_EV) {
1082	delete $SIG_EV{$_};	1269	delete $SIG_EV{$_};
1083	$_->() for values %{ $SIG_CB{$_} \|\| {} };	1270	$_->() for values %{ $SIG_CB{$_} \|\| {} };
1084	}	1271	}
1085	}	1272	}
1086	}	1273	}
1087		1274
		1275	# install a dumym wakeupw atcher to reduce signal catching latency
		1276	sub _sig_add() {
		1277	unless ($SIG_COUNT++) {
		1278	# try to align timer on a full-second boundary, if possible
		1279	my $NOW = AnyEvent->now;
		1280
		1281	$SIG_TW = AnyEvent->timer (
		1282	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1283	interval => $MAX_SIGNAL_LATENCY,
		1284	cb => sub { }, # just for the PERL_ASYNC_CHECK
		1285	);
		1286	}
		1287	}
		1288
		1289	sub _sig_del {
		1290	undef $SIG_TW
		1291	unless --$SIG_COUNT;
		1292	}
		1293
		1294	sub _signal {
		1295	my (undef, %arg) = @_;
		1296
		1297	my $signal = uc $arg{signal}
		1298	or Carp::croak "required option 'signal' is missing";
		1299
		1300	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1301
		1302	if ($HAVE_ASYNC_INTERRUPT) {
		1303	# async::interrupt
		1304
		1305	$SIG_ASY{$signal} \|\|= do {
		1306	my $asy = new Async::Interrupt
		1307	cb => sub { undef $SIG_EV{$signal} },
		1308	signal => $signal,
		1309	pipe => [$SIGPIPE_R->filenos],
		1310	;
		1311	$asy->pipe_autodrain (0);
		1312
		1313	$asy
		1314	};
		1315
		1316	} else {
		1317	# pure perl
		1318
		1319	$SIG{$signal} \|\|= sub {
		1320	local $!;
		1321	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1322	undef $SIG_EV{$signal};
		1323	};
		1324
		1325	# can't do signal processing without introducing races in pure perl,
		1326	# so limit the signal latency.
		1327	_sig_add;
		1328	}
		1329
		1330	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1331	}
		1332
1088	sub signal {	1333	sub signal {
1089	my (undef, %arg) = @_;	1334	# probe for availability of Async::Interrupt
		1335	if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
		1336	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1090		1337
1091	unless ($SIGPIPE_R) {	1338	$HAVE_ASYNC_INTERRUPT = 1;
		1339	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1340	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
		1341
		1342	} else {
		1343	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1344
1092	require Fcntl;	1345	require Fcntl;
1093		1346
1094	if (AnyEvent::WIN32) {	1347	if (AnyEvent::WIN32) {
1095	require AnyEvent::Util;	1348	require AnyEvent::Util;
1096		1349
…		…
1099	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case	1352	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1100	} else {	1353	} else {
1101	pipe $SIGPIPE_R, $SIGPIPE_W;	1354	pipe $SIGPIPE_R, $SIGPIPE_W;
1102	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1355	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1103	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1356	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1357
		1358	# not strictly required, as $^F is normally 2, but let's make sure...
		1359	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1360	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1104	}	1361	}
1105		1362
1106	$SIGPIPE_R	1363	$SIGPIPE_R
1107	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1364	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1108		1365
1109	# not strictly required, as $^F is normally 2, but let's make sure...
1110	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1111	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1112
1113	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1366	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1114	}	1367	}
1115		1368
1116	my $signal = uc $arg{signal}	1369	*signal = \&_signal;
1117	or Carp::croak "required option 'signal' is missing";	1370	&signal
1118
1119	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1120	$SIG{$signal} \|\|= sub {
1121	local $!;
1122	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1123	undef $SIG_EV{$signal};
1124	};
1125
1126	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
1127	}	1371	}
1128		1372
1129	sub AnyEvent::Base::Signal::DESTROY {	1373	sub AnyEvent::Base::signal::DESTROY {
1130	my ($signal, $cb) = @{$_[0]};	1374	my ($signal, $cb) = @{$_[0]};
1131		1375
		1376	_sig_del;
		1377
1132	delete $SIG_CB{$signal}{$cb};	1378	delete $SIG_CB{$signal}{$cb};
1133		1379
		1380	$HAVE_ASYNC_INTERRUPT
		1381	? delete $SIG_ASY{$signal}
		1382	: # delete doesn't work with older perls - they then
		1383	# print weird messages, or just unconditionally exit
		1384	# instead of getting the default action.
		1385	undef $SIG{$signal}
1134	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };	1386	unless keys %{ $SIG_CB{$signal} };
1135	}	1387	}
1136		1388
1137	# default implementation for ->child	1389	# default implementation for ->child
1138		1390
1139	our %PID_CB;	1391	our %PID_CB;
1140	our $CHLD_W;	1392	our $CHLD_W;
1141	our $CHLD_DELAY_W;	1393	our $CHLD_DELAY_W;
1142	our $PID_IDLE;
1143	our $WNOHANG;	1394	our $WNOHANG;
1144		1395
1145	sub _child_wait {	1396	sub _sigchld {
1146	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1397	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
		1398	$_->($pid, $?)
1147	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),	1399	for values %{ $PID_CB{$pid} \|\| {} },
1148	(values %{ $PID_CB{0} \|\| {} });	1400	values %{ $PID_CB{0} \|\| {} };
1149	}	1401	}
1150
1151	undef $PID_IDLE;
1152	}
1153
1154	sub _sigchld {
1155	# make sure we deliver these changes "synchronous" with the event loop.
1156	$CHLD_DELAY_W \|\|= AnyEvent->timer (after => 0, cb => sub {
1157	undef $CHLD_DELAY_W;
1158	&_child_wait;
1159	});
1160	}	1402	}
1161		1403
1162	sub child {	1404	sub child {
1163	my (undef, %arg) = @_;	1405	my (undef, %arg) = @_;
1164		1406
1165	defined (my $pid = $arg{pid} + 0)	1407	defined (my $pid = $arg{pid} + 0)
1166	or Carp::croak "required option 'pid' is missing";	1408	or Carp::croak "required option 'pid' is missing";
1167		1409
1168	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1410	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1169		1411
1170	unless ($WNOHANG) {	1412	# WNOHANG is almost cetrainly 1 everywhere
		1413	$WNOHANG \|\|= $^O =~ /^(?:openbsd\|netbsd\|linux\|freebsd\|cygwin\|MSWin32)$/
		1414	? 1
1171	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;	1415	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
1172	}
1173		1416
1174	unless ($CHLD_W) {	1417	unless ($CHLD_W) {
1175	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1418	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1176	# child could be a zombie already, so make at least one round	1419	# child could be a zombie already, so make at least one round
1177	&_sigchld;	1420	&_sigchld;
1178	}	1421	}
1179		1422
1180	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1423	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1181	}	1424	}
1182		1425
1183	sub AnyEvent::Base::Child::DESTROY {	1426	sub AnyEvent::Base::child::DESTROY {
1184	my ($pid, $cb) = @{$_[0]};	1427	my ($pid, $cb) = @{$_[0]};
1185		1428
1186	delete $PID_CB{$pid}{$cb};	1429	delete $PID_CB{$pid}{$cb};
1187	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1430	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1188		1431
1189	undef $CHLD_W unless keys %PID_CB;	1432	undef $CHLD_W unless keys %PID_CB;
1190	}	1433	}
1191		1434
		1435	# idle emulation is done by simply using a timer, regardless
		1436	# of whether the process is idle or not, and not letting
		1437	# the callback use more than 50% of the time.
		1438	sub idle {
		1439	my (undef, %arg) = @_;
		1440
		1441	my ($cb, $w, $rcb) = $arg{cb};
		1442
		1443	$rcb = sub {
		1444	if ($cb) {
		1445	$w = _time;
		1446	&$cb;
		1447	$w = _time - $w;
		1448
		1449	# never use more then 50% of the time for the idle watcher,
		1450	# within some limits
		1451	$w = 0.0001 if $w < 0.0001;
		1452	$w = 5 if $w > 5;
		1453
		1454	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1455	} else {
		1456	# clean up...
		1457	undef $w;
		1458	undef $rcb;
		1459	}
		1460	};
		1461
		1462	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1463
		1464	bless \\$cb, "AnyEvent::Base::idle"
		1465	}
		1466
		1467	sub AnyEvent::Base::idle::DESTROY {
		1468	undef $${$_[0]};
		1469	}
		1470
1192	package AnyEvent::CondVar;	1471	package AnyEvent::CondVar;
1193		1472
1194	our @ISA = AnyEvent::CondVar::Base::;	1473	our @ISA = AnyEvent::CondVar::Base::;
1195		1474
1196	package AnyEvent::CondVar::Base;	1475	package AnyEvent::CondVar::Base;
1197		1476
1198	use overload	1477	#use overload
1199	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1478	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1200	fallback => 1;	1479	# fallback => 1;
		1480
		1481	# save 300+ kilobytes by dirtily hardcoding overloading
		1482	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1483	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1484	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1485	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1486
		1487	our $WAITING;
1201		1488
1202	sub _send {	1489	sub _send {
1203	# nop	1490	# nop
1204	}	1491	}
1205		1492
…		…
1218	sub ready {	1505	sub ready {
1219	$_[0]{_ae_sent}	1506	$_[0]{_ae_sent}
1220	}	1507	}
1221		1508
1222	sub _wait {	1509	sub _wait {
		1510	$WAITING
		1511	and !$_[0]{_ae_sent}
		1512	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1513
		1514	local $WAITING = 1;
1223	AnyEvent->one_event while !$_[0]{_ae_sent};	1515	AnyEvent->one_event while !$_[0]{_ae_sent};
1224	}	1516	}
1225		1517
1226	sub recv {	1518	sub recv {
1227	$_[0]->_wait;	1519	$_[0]->_wait;
…		…
1268	so on.	1560	so on.
1269		1561
1270	=head1 ENVIRONMENT VARIABLES	1562	=head1 ENVIRONMENT VARIABLES
1271		1563
1272	The following environment variables are used by this module or its	1564	The following environment variables are used by this module or its
1273	submodules:	1565	submodules.
		1566
		1567	Note that AnyEvent will remove I<all> environment variables starting with
		1568	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1569	enabled.
1274		1570
1275	=over 4	1571	=over 4
1276		1572
1277	=item C<PERL_ANYEVENT_VERBOSE>	1573	=item C<PERL_ANYEVENT_VERBOSE>
1278		1574
…		…
1285	C<PERL_ANYEVENT_MODEL>.	1581	C<PERL_ANYEVENT_MODEL>.
1286		1582
1287	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1583	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1288	model it chooses.	1584	model it chooses.
1289		1585
		1586	When set to C<8> or higher, then AnyEvent will report extra information on
		1587	which optional modules it loads and how it implements certain features.
		1588
1290	=item C<PERL_ANYEVENT_STRICT>	1589	=item C<PERL_ANYEVENT_STRICT>
1291		1590
1292	AnyEvent does not do much argument checking by default, as thorough	1591	AnyEvent does not do much argument checking by default, as thorough
1293	argument checking is very costly. Setting this variable to a true value	1592	argument checking is very costly. Setting this variable to a true value
1294	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1593	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1295	check the arguments passed to most method calls. If it finds any problems	1594	check the arguments passed to most method calls. If it finds any problems,
1296	it will croak.	1595	it will croak.
1297		1596
1298	In other words, enables "strict" mode.	1597	In other words, enables "strict" mode.
1299		1598
1300	Unlike C<use strict>, it is definitely recommended ot keep it off in	1599	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1301	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1600	>>, it is definitely recommended to keep it off in production. Keeping
1302	developing programs can be very useful, however.	1601	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1602	can be very useful, however.
1303		1603
1304	=item C<PERL_ANYEVENT_MODEL>	1604	=item C<PERL_ANYEVENT_MODEL>
1305		1605
1306	This can be used to specify the event model to be used by AnyEvent, before	1606	This can be used to specify the event model to be used by AnyEvent, before
1307	auto detection and -probing kicks in. It must be a string consisting	1607	auto detection and -probing kicks in. It must be a string consisting
…		…
1350		1650
1351	=item C<PERL_ANYEVENT_MAX_FORKS>	1651	=item C<PERL_ANYEVENT_MAX_FORKS>
1352		1652
1353	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1653	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1354	will create in parallel.	1654	will create in parallel.
		1655
		1656	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1657
		1658	The default value for the C<max_outstanding> parameter for the default DNS
		1659	resolver - this is the maximum number of parallel DNS requests that are
		1660	sent to the DNS server.
		1661
		1662	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1663
		1664	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1665	configuration) in the default resolver. When set to the empty string, no
		1666	default config will be used.
		1667
		1668	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1669
		1670	When neither C<ca_file> nor C<ca_path> was specified during
		1671	L<AnyEvent::TLS> context creation, and either of these environment
		1672	variables exist, they will be used to specify CA certificate locations
		1673	instead of a system-dependent default.
		1674
		1675	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1676
		1677	When these are set to C<1>, then the respective modules are not
		1678	loaded. Mostly good for testing AnyEvent itself.
1355		1679
1356	=back	1680	=back
1357		1681
1358	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1682	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1359		1683
…		…
1604	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	1928	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1605	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	1929	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1606	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	1930	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1607	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	1931	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1608	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	1932	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		1933	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		1934	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1609	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	1935	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1610	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	1936	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1611	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	1937	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1612	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	1938	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1613		1939
…		…
1642	performance becomes really bad with lots of file descriptors (and few of	1968	performance becomes really bad with lots of file descriptors (and few of
1643	them active), of course, but this was not subject of this benchmark.	1969	them active), of course, but this was not subject of this benchmark.
1644		1970
1645	The C<Event> module has a relatively high setup and callback invocation	1971	The C<Event> module has a relatively high setup and callback invocation
1646	cost, but overall scores in on the third place.	1972	cost, but overall scores in on the third place.
		1973
		1974	C<IO::Async> performs admirably well, about on par with C<Event>, even
		1975	when using its pure perl backend.
1647		1976
1648	C<Glib>'s memory usage is quite a bit higher, but it features a	1977	C<Glib>'s memory usage is quite a bit higher, but it features a
1649	faster callback invocation and overall ends up in the same class as	1978	faster callback invocation and overall ends up in the same class as
1650	C<Event>. However, Glib scales extremely badly, doubling the number of	1979	C<Event>. However, Glib scales extremely badly, doubling the number of
1651	watchers increases the processing time by more than a factor of four,	1980	watchers increases the processing time by more than a factor of four,
…		…
1729	it to another server. This includes deleting the old timeout and creating	2058	it to another server. This includes deleting the old timeout and creating
1730	a new one that moves the timeout into the future.	2059	a new one that moves the timeout into the future.
1731		2060
1732	=head3 Results	2061	=head3 Results
1733		2062
1734	name sockets create request	2063	name sockets create request
1735	EV 20000 69.01 11.16	2064	EV 20000 69.01 11.16
1736	Perl 20000 73.32 35.87	2065	Perl 20000 73.32 35.87
		2066	IOAsync 20000 157.00 98.14 epoll
		2067	IOAsync 20000 159.31 616.06 poll
1737	Event 20000 212.62 257.32	2068	Event 20000 212.62 257.32
1738	Glib 20000 651.16 1896.30	2069	Glib 20000 651.16 1896.30
1739	POE 20000 349.67 12317.24 uses POE::Loop::Event	2070	POE 20000 349.67 12317.24 uses POE::Loop::Event
1740		2071
1741	=head3 Discussion	2072	=head3 Discussion
1742		2073
1743	This benchmark I<does> measure scalability and overall performance of the	2074	This benchmark I<does> measure scalability and overall performance of the
1744	particular event loop.	2075	particular event loop.
…		…
1746	EV is again fastest. Since it is using epoll on my system, the setup time	2077	EV is again fastest. Since it is using epoll on my system, the setup time
1747	is relatively high, though.	2078	is relatively high, though.
1748		2079
1749	Perl surprisingly comes second. It is much faster than the C-based event	2080	Perl surprisingly comes second. It is much faster than the C-based event
1750	loops Event and Glib.	2081	loops Event and Glib.
		2082
		2083	IO::Async performs very well when using its epoll backend, and still quite
		2084	good compared to Glib when using its pure perl backend.
1751		2085
1752	Event suffers from high setup time as well (look at its code and you will	2086	Event suffers from high setup time as well (look at its code and you will
1753	understand why). Callback invocation also has a high overhead compared to	2087	understand why). Callback invocation also has a high overhead compared to
1754	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2088	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1755	uses select or poll in basically all documented configurations.	2089	uses select or poll in basically all documented configurations.
…		…
1818	=item * C-based event loops perform very well with small number of	2152	=item * C-based event loops perform very well with small number of
1819	watchers, as the management overhead dominates.	2153	watchers, as the management overhead dominates.
1820		2154
1821	=back	2155	=back
1822		2156
		2157	=head2 THE IO::Lambda BENCHMARK
		2158
		2159	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2160	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2161	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2162	shouldn't come as a surprise to anybody). As such, the benchmark is
		2163	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2164	very optimal. But how would AnyEvent compare when used without the extra
		2165	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2166
		2167	The benchmark itself creates an echo-server, and then, for 500 times,
		2168	connects to the echo server, sends a line, waits for the reply, and then
		2169	creates the next connection. This is a rather bad benchmark, as it doesn't
		2170	test the efficiency of the framework or much non-blocking I/O, but it is a
		2171	benchmark nevertheless.
		2172
		2173	name runtime
		2174	Lambda/select 0.330 sec
		2175	+ optimized 0.122 sec
		2176	Lambda/AnyEvent 0.327 sec
		2177	+ optimized 0.138 sec
		2178	Raw sockets/select 0.077 sec
		2179	POE/select, components 0.662 sec
		2180	POE/select, raw sockets 0.226 sec
		2181	POE/select, optimized 0.404 sec
		2182
		2183	AnyEvent/select/nb 0.085 sec
		2184	AnyEvent/EV/nb 0.068 sec
		2185	+state machine 0.134 sec
		2186
		2187	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2188	benchmarks actually make blocking connects and use 100% blocking I/O,
		2189	defeating the purpose of an event-based solution. All of the newly
		2190	written AnyEvent benchmarks use 100% non-blocking connects (using
		2191	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2192	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2193	generally require a lot more bookkeeping and event handling than blocking
		2194	connects (which involve a single syscall only).
		2195
		2196	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2197	offers similar expressive power as POE and IO::Lambda, using conventional
		2198	Perl syntax. This means that both the echo server and the client are 100%
		2199	non-blocking, further placing it at a disadvantage.
		2200
		2201	As you can see, the AnyEvent + EV combination even beats the
		2202	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2203	backend easily beats IO::Lambda and POE.
		2204
		2205	And even the 100% non-blocking version written using the high-level (and
		2206	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2207	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2208	in a non-blocking way.
		2209
		2210	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2211	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2212	part of the IO::lambda distribution and were used without any changes.
		2213
1823		2214
1824	=head1 SIGNALS	2215	=head1 SIGNALS
1825		2216
1826	AnyEvent currently installs handlers for these signals:	2217	AnyEvent currently installs handlers for these signals:
1827		2218
…		…
1830	=item SIGCHLD	2221	=item SIGCHLD
1831		2222
1832	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2223	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1833	emulation for event loops that do not support them natively. Also, some	2224	emulation for event loops that do not support them natively. Also, some
1834	event loops install a similar handler.	2225	event loops install a similar handler.
		2226
		2227	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2228	AnyEvent will reset it to default, to avoid losing child exit statuses.
1835		2229
1836	=item SIGPIPE	2230	=item SIGPIPE
1837		2231
1838	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2232	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1839	when AnyEvent gets loaded.	2233	when AnyEvent gets loaded.
…		…
1851		2245
1852	=back	2246	=back
1853		2247
1854	=cut	2248	=cut
1855		2249
		2250	undef $SIG{CHLD}
		2251	if $SIG{CHLD} eq 'IGNORE';
		2252
1856	$SIG{PIPE} = sub { }	2253	$SIG{PIPE} = sub { }
1857	unless defined $SIG{PIPE};	2254	unless defined $SIG{PIPE};
		2255
		2256	=head1 RECOMMENDED/OPTIONAL MODULES
		2257
		2258	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2259	it's built-in modules) are required to use it.
		2260
		2261	That does not mean that AnyEvent won't take advantage of some additional
		2262	modules if they are installed.
		2263
		2264	This section epxlains which additional modules will be used, and how they
		2265	affect AnyEvent's operetion.
		2266
		2267	=over 4
		2268
		2269	=item L<Async::Interrupt>
		2270
		2271	This slightly arcane module is used to implement fast signal handling: To
		2272	my knowledge, there is no way to do completely race-free and quick
		2273	signal handling in pure perl. To ensure that signals still get
		2274	delivered, AnyEvent will start an interval timer to wake up perl (and
		2275	catch the signals) with soemd elay (default is 10 seconds, look for
		2276	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2277
		2278	If this module is available, then it will be used to implement signal
		2279	catching, which means that signals will not be delayed, and the event loop
		2280	will not be interrupted regularly, which is more efficient (And good for
		2281	battery life on laptops).
		2282
		2283	This affects not just the pure-perl event loop, but also other event loops
		2284	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2285
		2286	=item L<EV>
		2287
		2288	This module isn't really "optional", as it is simply one of the backend
		2289	event loops that AnyEvent can use. However, it is simply the best event
		2290	loop available in terms of features, speed and stability: It supports
		2291	the AnyEvent API optimally, implements all the watcher types in XS, does
		2292	automatic timer adjustments even when no monotonic clock is available,
		2293	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2294	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2295	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2296
		2297	=item L<Guard>
		2298
		2299	The guard module, when used, will be used to implement
		2300	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2301	lot less memory), but otherwise doesn't affect guard operation much. It is
		2302	purely used for performance.
		2303
		2304	=item L<JSON> and L<JSON::XS>
		2305
		2306	This module is required when you want to read or write JSON data via
		2307	L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2308	advantage of the ulta-high-speed L<JSON::XS> module when it is installed.
		2309
		2310	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2311	installed.
		2312
		2313	=item L<Net::SSLeay>
		2314
		2315	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2316	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2317	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2318
		2319	=item L<Time::HiRes>
		2320
		2321	This module is part of perl since release 5.008. It will be used when the
		2322	chosen event library does not come with a timing source on it's own. The
		2323	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2324	try to use a monotonic clock for timing stability.
		2325
		2326	=back
1858		2327
1859		2328
1860	=head1 FORK	2329	=head1 FORK
1861		2330
1862	Most event libraries are not fork-safe. The ones who are usually are	2331	Most event libraries are not fork-safe. The ones who are usually are
1863	because they rely on inefficient but fork-safe C<select> or C<poll>	2332	because they rely on inefficient but fork-safe C<select> or C<poll>
1864	calls. Only L<EV> is fully fork-aware.	2333	calls. Only L<EV> is fully fork-aware.
1865		2334
1866	If you have to fork, you must either do so I<before> creating your first	2335	If you have to fork, you must either do so I<before> creating your first
1867	watcher OR you must not use AnyEvent at all in the child.	2336	watcher OR you must not use AnyEvent at all in the child OR you must do
		2337	something completely out of the scope of AnyEvent.
1868		2338
1869		2339
1870	=head1 SECURITY CONSIDERATIONS	2340	=head1 SECURITY CONSIDERATIONS
1871		2341
1872	AnyEvent can be forced to load any event model via	2342	AnyEvent can be forced to load any event model via
…		…
1884	use AnyEvent;	2354	use AnyEvent;
1885		2355
1886	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2356	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1887	be used to probe what backend is used and gain other information (which is	2357	be used to probe what backend is used and gain other information (which is
1888	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2358	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1889	$ENV{PERL_ANYEGENT_STRICT}.	2359	$ENV{PERL_ANYEVENT_STRICT}.
		2360
		2361	Note that AnyEvent will remove I<all> environment variables starting with
		2362	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2363	enabled.
1890		2364
1891		2365
1892	=head1 BUGS	2366	=head1 BUGS
1893		2367
1894	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2368	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
…		…
1906	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2380	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1907		2381
1908	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2382	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1909	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2383	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1910	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2384	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1911	L<AnyEvent::Impl::POE>.	2385	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.
1912		2386
1913	Non-blocking file handles, sockets, TCP clients and	2387	Non-blocking file handles, sockets, TCP clients and
1914	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2388	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1915		2389
1916	Asynchronous DNS: L<AnyEvent::DNS>.	2390	Asynchronous DNS: L<AnyEvent::DNS>.
1917		2391
1918	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2392	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2393	L<Coro::Event>,
1919		2394
1920	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2395	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2396	L<AnyEvent::HTTP>.
1921		2397
1922		2398
1923	=head1 AUTHOR	2399	=head1 AUTHOR
1924		2400
1925	Marc Lehmann <schmorp@schmorp.de>	2401	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.205 by root, Sun Apr 19 12:09:46 2009 UTC vs. Revision 1.246 by root, Sat Jul 18 15:51:52 2009 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.205 by root, Sun Apr 19 12:09:46 2009 UTC vs.
Revision 1.246 by root, Sat Jul 18 15:51:52 2009 UTC