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Revision 1.201 by root, Wed Apr 1 14:08:27 2009 UTC vs.
Revision 1.251 by root, Mon Jul 20 22:39:57 2009 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - events independent of event loop implementation
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:
…		…
32	=head1 INTRODUCTION/TUTORIAL	40	=head1 INTRODUCTION/TUTORIAL
33		41
34	This manpage is mainly a reference manual. If you are interested	42	This manpage is mainly a reference manual. If you are interested
35	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
36	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	Respository>, at L<http://anyevent.schmorp.de>, for more info.
37		53
38	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	54	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
39		55
40	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
41	nowadays. So what is different about AnyEvent?	57	nowadays. So what is different about AnyEvent?
…		…
168	=head2 I/O WATCHERS	184	=head2 I/O WATCHERS
169		185
170	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
171	with the following mandatory key-value pairs as arguments:	187	with the following mandatory key-value pairs as arguments:
172		188
173	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
174	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
175	handle). Note that only file handles pointing to things for which	191	handle). Note that only file handles pointing to things for which
176	non-blocking operation makes sense are allowed. This includes sockets,	192	non-blocking operation makes sense are allowed. This includes sockets,
177	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
178	or block devices.	194	or block devices.
…		…
320	In either case, if you care (and in most cases, you don't), then you	336	In either case, if you care (and in most cases, you don't), then you
321	can get whatever behaviour you want with any event loop, by taking the	337	can get whatever behaviour you want with any event loop, by taking the
322	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	338	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
323	account.	339	account.
324		340
		341	=item AnyEvent->now_update
		342
		343	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		344	the current time for each loop iteration (see the discussion of L<<
		345	AnyEvent->now >>, above).
		346
		347	When a callback runs for a long time (or when the process sleeps), then
		348	this "current" time will differ substantially from the real time, which
		349	might affect timers and time-outs.
		350
		351	When this is the case, you can call this method, which will update the
		352	event loop's idea of "current time".
		353
		354	Note that updating the time I<might> cause some events to be handled.
		355
325	=back	356	=back
326		357
327	=head2 SIGNAL WATCHERS	358	=head2 SIGNAL WATCHERS
328		359
329	You can watch for signals using a signal watcher, C<signal> is the signal	360	You can watch for signals using a signal watcher, C<signal> is the signal
…		…
338	invocation, and callback invocation will be synchronous. Synchronous means	369	invocation, and callback invocation will be synchronous. Synchronous means
339	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,
340	but it is guaranteed not to interrupt any other callbacks.	371	but it is guaranteed not to interrupt any other callbacks.
341		372
342	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
343	between multiple watchers.	374	between multiple watchers, and AnyEvent will ensure that signals will not
		375	interrupt your program at bad times.
344		376
345	This watcher might use C<%SIG>, so programs overwriting those signals	377	This watcher might use C<%SIG> (depending on the event loop used),
346	directly will likely not work correctly.	378	so programs overwriting those signals directly will likely not work
		379	correctly.
347		380
348	Example: exit on SIGINT	381	Example: exit on SIGINT
349		382
350	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	383	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
		384
		385	=head3 Signal Races, Delays and Workarounds
		386
		387	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		388	callbacks to signals in a generic way, which is a pity, as you cannot do
		389	race-free signal handling in perl. AnyEvent will try to do it's best, but
		390	in some cases, signals will be delayed. The maximum time a signal might
		391	be delayed is specified in C<$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.
351		400
352	=head2 CHILD PROCESS WATCHERS	401	=head2 CHILD PROCESS WATCHERS
353		402
354	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.
355		404
…		…
369		418
370	There is a slight catch to child watchers, however: you usually start them	419	There is a slight catch to child watchers, however: you usually start them
371	I<after> the child process was created, and this means the process could	420	I<after> the child process was created, and this means the process could
372	have exited already (and no SIGCHLD will be sent anymore).	421	have exited already (and no SIGCHLD will be sent anymore).
373		422
374	Not all event models handle this correctly (POE doesn't), but even for	423	Not all event models handle this correctly (neither POE nor IO::Async do,
		424	see their AnyEvent::Impl manpages for details), but even for event models
375	event models that I<do> handle this correctly, they usually need to be	425	that I<do> handle this correctly, they usually need to be loaded before
376	loaded before the process exits (i.e. before you fork in the first place).	426	the process exits (i.e. before you fork in the first place). AnyEvent's
		427	pure perl event loop handles all cases correctly regardless of when you
		428	start the watcher.
377		429
378	This means you cannot create a child watcher as the very first thing in an	430	This means you cannot create a child watcher as the very first
379	AnyEvent program, you I<have> to create at least one watcher before you	431	thing in an AnyEvent program, you I<have> to create at least one
380	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	432	watcher before you C<fork> the child (alternatively, you can call
		433	C<AnyEvent::detect>).
		434
		435	As most event loops do not support waiting for child events, they will be
		436	emulated by AnyEvent in most cases, in which the latency and race problems
		437	mentioned in the description of signal watchers apply.
381		438
382	Example: fork a process and wait for it	439	Example: fork a process and wait for it
383		440
384	my $done = AnyEvent->condvar;	441	my $done = AnyEvent->condvar;
385		442
…		…
395	);	452	);
396		453
397	# do something else, then wait for process exit	454	# do something else, then wait for process exit
398	$done->recv;	455	$done->recv;
399		456
		457	=head2 IDLE WATCHERS
		458
		459	Sometimes there is a need to do something, but it is not so important
		460	to do it instantly, but only when there is nothing better to do. This
		461	"nothing better to do" is usually defined to be "no other events need
		462	attention by the event loop".
		463
		464	Idle watchers ideally get invoked when the event loop has nothing
		465	better to do, just before it would block the process to wait for new
		466	events. Instead of blocking, the idle watcher is invoked.
		467
		468	Most event loops unfortunately do not really support idle watchers (only
		469	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		470	will simply call the callback "from time to time".
		471
		472	Example: read lines from STDIN, but only process them when the
		473	program is otherwise idle:
		474
		475	my @lines; # read data
		476	my $idle_w;
		477	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		478	push @lines, scalar <STDIN>;
		479
		480	# start an idle watcher, if not already done
		481	$idle_w ||= AnyEvent->idle (cb => sub {
		482	# handle only one line, when there are lines left
		483	if (my $line = shift @lines) {
		484	print "handled when idle: $line";
		485	} else {
		486	# otherwise disable the idle watcher again
		487	undef $idle_w;
		488	}
		489	});
		490	});
		491
400	=head2 CONDITION VARIABLES	492	=head2 CONDITION VARIABLES
401		493
402	If you are familiar with some event loops you will know that all of them	494	If you are familiar with some event loops you will know that all of them
403	require you to run some blocking "loop", "run" or similar function that	495	require you to run some blocking "loop", "run" or similar function that
404	will actively watch for new events and call your callbacks.	496	will actively watch for new events and call your callbacks.
405		497
406	AnyEvent is different, it expects somebody else to run the event loop and	498	AnyEvent is slightly different: it expects somebody else to run the event
407	will only block when necessary (usually when told by the user).	499	loop and will only block when necessary (usually when told by the user).
408		500
409	The instrument to do that is called a "condition variable", so called	501	The instrument to do that is called a "condition variable", so called
410	because they represent a condition that must become true.	502	because they represent a condition that must become true.
411		503
		504	Now is probably a good time to look at the examples further below.
		505
412	Condition variables can be created by calling the C<< AnyEvent->condvar	506	Condition variables can be created by calling the C<< AnyEvent->condvar
413	>> method, usually without arguments. The only argument pair allowed is	507	>> method, usually without arguments. The only argument pair allowed is
414
415	C<cb>, which specifies a callback to be called when the condition variable	508	C<cb>, which specifies a callback to be called when the condition variable
416	becomes true, with the condition variable as the first argument (but not	509	becomes true, with the condition variable as the first argument (but not
417	the results).	510	the results).
418		511
419	After creation, the condition variable is "false" until it becomes "true"	512	After creation, the condition variable is "false" until it becomes "true"
…		…
424	Condition variables are similar to callbacks, except that you can	517	Condition variables are similar to callbacks, except that you can
425	optionally wait for them. They can also be called merge points - points	518	optionally wait for them. They can also be called merge points - points
426	in time where multiple outstanding events have been processed. And yet	519	in time where multiple outstanding events have been processed. And yet
427	another way to call them is transactions - each condition variable can be	520	another way to call them is transactions - each condition variable can be
428	used to represent a transaction, which finishes at some point and delivers	521	used to represent a transaction, which finishes at some point and delivers
429	a result.	522	a result. And yet some people know them as "futures" - a promise to
		523	compute/deliver something that you can wait for.
430		524
431	Condition variables are very useful to signal that something has finished,	525	Condition variables are very useful to signal that something has finished,
432	for example, if you write a module that does asynchronous http requests,	526	for example, if you write a module that does asynchronous http requests,
433	then a condition variable would be the ideal candidate to signal the	527	then a condition variable would be the ideal candidate to signal the
434	availability of results. The user can either act when the callback is	528	availability of results. The user can either act when the callback is
…		…
468	after => 1,	562	after => 1,
469	cb => sub { $result_ready->send },	563	cb => sub { $result_ready->send },
470	);	564	);
471		565
472	# this "blocks" (while handling events) till the callback	566	# this "blocks" (while handling events) till the callback
473	# calls send	567	# calls -<send
474	$result_ready->recv;	568	$result_ready->recv;
475		569
476	Example: wait for a timer, but take advantage of the fact that	570	Example: wait for a timer, but take advantage of the fact that condition
477	condition variables are also code references.	571	variables are also callable directly.
478		572
479	my $done = AnyEvent->condvar;	573	my $done = AnyEvent->condvar;
480	my $delay = AnyEvent->timer (after => 5, cb => $done);	574	my $delay = AnyEvent->timer (after => 5, cb => $done);
481	$done->recv;	575	$done->recv;
482		576
…		…
488		582
489	...	583	...
490		584
491	my @info = $couchdb->info->recv;	585	my @info = $couchdb->info->recv;
492		586
493	And this is how you would just ste a callback to be called whenever the	587	And this is how you would just set a callback to be called whenever the
494	results are available:	588	results are available:
495		589
496	$couchdb->info->cb (sub {	590	$couchdb->info->cb (sub {
497	my @info = $_[0]->recv;	591	my @info = $_[0]->recv;
498	});	592	});
…		…
516	immediately from within send.	610	immediately from within send.
517		611
518	Any arguments passed to the C<send> call will be returned by all	612	Any arguments passed to the C<send> call will be returned by all
519	future C<< ->recv >> calls.	613	future C<< ->recv >> calls.
520		614
521	Condition variables are overloaded so one can call them directly	615	Condition variables are overloaded so one can call them directly (as if
522	(as a code reference). Calling them directly is the same as calling	616	they were a code reference). Calling them directly is the same as calling
523	C<send>. Note, however, that many C-based event loops do not handle	617	C<send>.
524	overloading, so as tempting as it may be, passing a condition variable
525	instead of a callback does not work. Both the pure perl and EV loops
526	support overloading, however, as well as all functions that use perl to
527	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
528	example).
529		618
530	=item $cv->croak ($error)	619	=item $cv->croak ($error)
531		620
532	Similar to send, but causes all call's to C<< ->recv >> to invoke	621	Similar to send, but causes all call's to C<< ->recv >> to invoke
533	C<Carp::croak> with the given error message/object/scalar.	622	C<Carp::croak> with the given error message/object/scalar.
534		623
535	This can be used to signal any errors to the condition variable	624	This can be used to signal any errors to the condition variable
536	user/consumer.	625	user/consumer. Doing it this way instead of calling C<croak> directly
		626	delays the error detetcion, but has the overwhelmign advantage that it
		627	diagnoses the error at the place where the result is expected, and not
		628	deep in some event clalback without connection to the actual code causing
		629	the problem.
537		630
538	=item $cv->begin ([group callback])	631	=item $cv->begin ([group callback])
539		632
540	=item $cv->end	633	=item $cv->end
541
542	These two methods are EXPERIMENTAL and MIGHT CHANGE.
543		634
544	These two methods can be used to combine many transactions/events into	635	These two methods can be used to combine many transactions/events into
545	one. For example, a function that pings many hosts in parallel might want	636	one. For example, a function that pings many hosts in parallel might want
546	to use a condition variable for the whole process.	637	to use a condition variable for the whole process.
547		638
…		…
549	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	640	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
550	>>, the (last) callback passed to C<begin> will be executed. That callback	641	>>, the (last) callback passed to C<begin> will be executed. That callback
551	is I<supposed> to call C<< ->send >>, but that is not required. If no	642	is I<supposed> to call C<< ->send >>, but that is not required. If no
552	callback was set, C<send> will be called without any arguments.	643	callback was set, C<send> will be called without any arguments.
553		644
554	Let's clarify this with the ping example:	645	You can think of C<< $cv->send >> giving you an OR condition (one call
		646	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		647	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		648
		649	Let's start with a simple example: you have two I/O watchers (for example,
		650	STDOUT and STDERR for a program), and you want to wait for both streams to
		651	close before activating a condvar:
		652
		653	my $cv = AnyEvent->condvar;
		654
		655	$cv->begin; # first watcher
		656	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		657	defined sysread $fh1, my $buf, 4096
		658	or $cv->end;
		659	});
		660
		661	$cv->begin; # second watcher
		662	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		663	defined sysread $fh2, my $buf, 4096
		664	or $cv->end;
		665	});
		666
		667	$cv->recv;
		668
		669	This works because for every event source (EOF on file handle), there is
		670	one call to C<begin>, so the condvar waits for all calls to C<end> before
		671	sending.
		672
		673	The ping example mentioned above is slightly more complicated, as the
		674	there are results to be passwd back, and the number of tasks that are
		675	begung can potentially be zero:
555		676
556	my $cv = AnyEvent->condvar;	677	my $cv = AnyEvent->condvar;
557		678
558	my %result;	679	my %result;
559	$cv->begin (sub { $cv->send (\%result) });	680	$cv->begin (sub { $cv->send (\%result) });
…		…
579	loop, which serves two important purposes: first, it sets the callback	700	loop, which serves two important purposes: first, it sets the callback
580	to be called once the counter reaches C<0>, and second, it ensures that	701	to be called once the counter reaches C<0>, and second, it ensures that
581	C<send> is called even when C<no> hosts are being pinged (the loop	702	C<send> is called even when C<no> hosts are being pinged (the loop
582	doesn't execute once).	703	doesn't execute once).
583		704
584	This is the general pattern when you "fan out" into multiple subrequests:	705	This is the general pattern when you "fan out" into multiple (but
585	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	706	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
586	is called at least once, and then, for each subrequest you start, call	707	the callback and ensure C<end> is called at least once, and then, for each
587	C<begin> and for each subrequest you finish, call C<end>.	708	subrequest you start, call C<begin> and for each subrequest you finish,
		709	call C<end>.
588		710
589	=back	711	=back
590		712
591	=head3 METHODS FOR CONSUMERS	713	=head3 METHODS FOR CONSUMERS
592		714
…		…
608	function will call C<croak>.	730	function will call C<croak>.
609		731
610	In list context, all parameters passed to C<send> will be returned,	732	In list context, all parameters passed to C<send> will be returned,
611	in scalar context only the first one will be returned.	733	in scalar context only the first one will be returned.
612		734
		735	Note that doing a blocking wait in a callback is not supported by any
		736	event loop, that is, recursive invocation of a blocking C<< ->recv
		737	>> is not allowed, and the C<recv> call will C<croak> if such a
		738	condition is detected. This condition can be slightly loosened by using
		739	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		740	any thread that doesn't run the event loop itself.
		741
613	Not all event models support a blocking wait - some die in that case	742	Not all event models support a blocking wait - some die in that case
614	(programs might want to do that to stay interactive), so I<if you are	743	(programs might want to do that to stay interactive), so I<if you are
615	using this from a module, never require a blocking wait>, but let the	744	using this from a module, never require a blocking wait>. Instead, let the
616	caller decide whether the call will block or not (for example, by coupling	745	caller decide whether the call will block or not (for example, by coupling
617	condition variables with some kind of request results and supporting	746	condition variables with some kind of request results and supporting
618	callbacks so the caller knows that getting the result will not block,	747	callbacks so the caller knows that getting the result will not block,
619	while still supporting blocking waits if the caller so desires).	748	while still supporting blocking waits if the caller so desires).
620		749
621	Another reason I<never> to C<< ->recv >> in a module is that you cannot
622	sensibly have two C<< ->recv >>'s in parallel, as that would require
623	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
624	can supply.
625
626	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
627	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
628	versions and also integrates coroutines into AnyEvent, making blocking
629	C<< ->recv >> calls perfectly safe as long as they are done from another
630	coroutine (one that doesn't run the event loop).
631
632	You can ensure that C<< -recv >> never blocks by setting a callback and	750	You can ensure that C<< -recv >> never blocks by setting a callback and
633	only calling C<< ->recv >> from within that callback (or at a later	751	only calling C<< ->recv >> from within that callback (or at a later
634	time). This will work even when the event loop does not support blocking	752	time). This will work even when the event loop does not support blocking
635	waits otherwise.	753	waits otherwise.
636		754
…		…
649	variable itself. Calling C<recv> inside the callback or at any later time	767	variable itself. Calling C<recv> inside the callback or at any later time
650	is guaranteed not to block.	768	is guaranteed not to block.
651		769
652	=back	770	=back
653		771
		772	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		773
		774	The available backend classes are (every class has its own manpage):
		775
		776	=over 4
		777
		778	=item Backends that are autoprobed when no other event loop can be found.
		779
		780	EV is the preferred backend when no other event loop seems to be in
		781	use. If EV is not installed, then AnyEvent will try Event, and, failing
		782	that, will fall back to its own pure-perl implementation, which is
		783	available everywhere as it comes with AnyEvent itself.
		784
		785	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		786	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		787	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		788
		789	=item Backends that are transparently being picked up when they are used.
		790
		791	These will be used when they are currently loaded when the first watcher
		792	is created, in which case it is assumed that the application is using
		793	them. This means that AnyEvent will automatically pick the right backend
		794	when the main program loads an event module before anything starts to
		795	create watchers. Nothing special needs to be done by the main program.
		796
		797	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		798	AnyEvent::Impl::Tk based on Tk, very broken.
		799	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		800	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		801
		802	=item Backends with special needs.
		803
		804	Qt requires the Qt::Application to be instantiated first, but will
		805	otherwise be picked up automatically. As long as the main program
		806	instantiates the application before any AnyEvent watchers are created,
		807	everything should just work.
		808
		809	AnyEvent::Impl::Qt based on Qt.
		810
		811	Support for IO::Async can only be partial, as it is too broken and
		812	architecturally limited to even support the AnyEvent API. It also
		813	is the only event loop that needs the loop to be set explicitly, so
		814	it can only be used by a main program knowing about AnyEvent. See
		815	L<AnyEvent::Impl::Async> for the gory details.
		816
		817	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		818
		819	=item Event loops that are indirectly supported via other backends.
		820
		821	Some event loops can be supported via other modules:
		822
		823	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		824
		825	B<WxWidgets> has no support for watching file handles. However, you can
		826	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		827	polls 20 times per second, which was considered to be too horrible to even
		828	consider for AnyEvent.
		829
		830	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		831	backend, so it can be supported through POE.
		832
		833	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		834	load L<POE> when detecting them, in the hope that POE will pick them up,
		835	in which case everything will be automatic.
		836
		837	=back
		838
654	=head1 GLOBAL VARIABLES AND FUNCTIONS	839	=head1 GLOBAL VARIABLES AND FUNCTIONS
655		840
		841	These are not normally required to use AnyEvent, but can be useful to
		842	write AnyEvent extension modules.
		843
656	=over 4	844	=over 4
657		845
658	=item $AnyEvent::MODEL	846	=item $AnyEvent::MODEL
659		847
660	Contains C<undef> until the first watcher is being created. Then it	848	Contains C<undef> until the first watcher is being created, before the
		849	backend has been autodetected.
		850
661	contains the event model that is being used, which is the name of the	851	Afterwards it contains the event model that is being used, which is the
662	Perl class implementing the model. This class is usually one of the	852	name of the Perl class implementing the model. This class is usually one
663	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	853	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
664	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	854	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
665		855	will be C<urxvt::anyevent>).
666	The known classes so far are:
667
668	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
669	AnyEvent::Impl::Event based on Event, second best choice.
670	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
671	AnyEvent::Impl::Glib based on Glib, third-best choice.
672	AnyEvent::Impl::Tk based on Tk, very bad choice.
673	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
674	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
675	AnyEvent::Impl::POE based on POE, not generic enough for full support.
676
677	There is no support for WxWidgets, as WxWidgets has no support for
678	watching file handles. However, you can use WxWidgets through the
679	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
680	second, which was considered to be too horrible to even consider for
681	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
682	it's adaptor.
683
684	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
685	autodetecting them.
686		856
687	=item AnyEvent::detect	857	=item AnyEvent::detect
688		858
689	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	859	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
690	if necessary. You should only call this function right before you would	860	if necessary. You should only call this function right before you would
691	have created an AnyEvent watcher anyway, that is, as late as possible at	861	have created an AnyEvent watcher anyway, that is, as late as possible at
692	runtime.	862	runtime, and not e.g. while initialising of your module.
		863
		864	If you need to do some initialisation before AnyEvent watchers are
		865	created, use C<post_detect>.
693		866
694	=item $guard = AnyEvent::post_detect { BLOCK }	867	=item $guard = AnyEvent::post_detect { BLOCK }
695		868
696	Arranges for the code block to be executed as soon as the event model is	869	Arranges for the code block to be executed as soon as the event model is
697	autodetected (or immediately if this has already happened).	870	autodetected (or immediately if this has already happened).
		871
		872	The block will be executed I<after> the actual backend has been detected
		873	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		874	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		875	other initialisations - see the sources of L<AnyEvent::Strict> or
		876	L<AnyEvent::AIO> to see how this is used.
		877
		878	The most common usage is to create some global watchers, without forcing
		879	event module detection too early, for example, L<AnyEvent::AIO> creates
		880	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		881	avoid autodetecting the event module at load time.
698		882
699	If called in scalar or list context, then it creates and returns an object	883	If called in scalar or list context, then it creates and returns an object
700	that automatically removes the callback again when it is destroyed. See	884	that automatically removes the callback again when it is destroyed. See
701	L<Coro::BDB> for a case where this is useful.	885	L<Coro::BDB> for a case where this is useful.
702		886
…		…
705	If there are any code references in this array (you can C<push> to it	889	If there are any code references in this array (you can C<push> to it
706	before or after loading AnyEvent), then they will called directly after	890	before or after loading AnyEvent), then they will called directly after
707	the event loop has been chosen.	891	the event loop has been chosen.
708		892
709	You should check C<$AnyEvent::MODEL> before adding to this array, though:	893	You should check C<$AnyEvent::MODEL> before adding to this array, though:
710	if it contains a true value then the event loop has already been detected,	894	if it is defined then the event loop has already been detected, and the
711	and the array will be ignored.	895	array will be ignored.
712		896
713	Best use C<AnyEvent::post_detect { BLOCK }> instead.	897	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		898	it,as it takes care of these details.
		899
		900	This variable is mainly useful for modules that can do something useful
		901	when AnyEvent is used and thus want to know when it is initialised, but do
		902	not need to even load it by default. This array provides the means to hook
		903	into AnyEvent passively, without loading it.
714		904
715	=back	905	=back
716		906
717	=head1 WHAT TO DO IN A MODULE	907	=head1 WHAT TO DO IN A MODULE
718		908
…		…
773		963
774		964
775	=head1 OTHER MODULES	965	=head1 OTHER MODULES
776		966
777	The following is a non-exhaustive list of additional modules that use	967	The following is a non-exhaustive list of additional modules that use
778	AnyEvent and can therefore be mixed easily with other AnyEvent modules	968	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
779	in the same program. Some of the modules come with AnyEvent, some are	969	modules and other event loops in the same program. Some of the modules
780	available via CPAN.	970	come with AnyEvent, most are available via CPAN.
781		971
782	=over 4	972	=over 4
783		973
784	=item L<AnyEvent::Util>	974	=item L<AnyEvent::Util>
785		975
…		…
794		984
795	=item L<AnyEvent::Handle>	985	=item L<AnyEvent::Handle>
796		986
797	Provide read and write buffers, manages watchers for reads and writes,	987	Provide read and write buffers, manages watchers for reads and writes,
798	supports raw and formatted I/O, I/O queued and fully transparent and	988	supports raw and formatted I/O, I/O queued and fully transparent and
799	non-blocking SSL/TLS.	989	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
800		990
801	=item L<AnyEvent::DNS>	991	=item L<AnyEvent::DNS>
802		992
803	Provides rich asynchronous DNS resolver capabilities.	993	Provides rich asynchronous DNS resolver capabilities.
804		994
…		…
832		1022
833	=item L<AnyEvent::GPSD>	1023	=item L<AnyEvent::GPSD>
834		1024
835	A non-blocking interface to gpsd, a daemon delivering GPS information.	1025	A non-blocking interface to gpsd, a daemon delivering GPS information.
836		1026
		1027	=item L<AnyEvent::IRC>
		1028
		1029	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1030
		1031	=item L<AnyEvent::XMPP>
		1032
		1033	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1034	Net::XMPP2>.
		1035
837	=item L<AnyEvent::IGS>	1036	=item L<AnyEvent::IGS>
838		1037
839	A non-blocking interface to the Internet Go Server protocol (used by	1038	A non-blocking interface to the Internet Go Server protocol (used by
840	L<App::IGS>).	1039	L<App::IGS>).
841		1040
842	=item L<AnyEvent::IRC>
843
844	AnyEvent based IRC client module family (replacing the older Net::IRC3).
845
846	=item L<Net::XMPP2>
847
848	AnyEvent based XMPP (Jabber protocol) module family.
849
850	=item L<Net::FCP>	1041	=item L<Net::FCP>
851		1042
852	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1043	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
853	of AnyEvent.	1044	of AnyEvent.
854		1045
…		…
858		1049
859	=item L<Coro>	1050	=item L<Coro>
860		1051
861	Has special support for AnyEvent via L<Coro::AnyEvent>.	1052	Has special support for AnyEvent via L<Coro::AnyEvent>.
862		1053
863	=item L<IO::Lambda>
864
865	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
866
867	=back	1054	=back
868		1055
869	=cut	1056	=cut
870		1057
871	package AnyEvent;	1058	package AnyEvent;
872		1059
		1060	# basically a tuned-down version of common::sense
		1061	sub common_sense {
873	no warnings;	1062	# no warnings
		1063	${^WARNING_BITS} ^= ${^WARNING_BITS};
874	use strict qw(vars subs);	1064	# use strict vars subs
		1065	$^H |= 0x00000600;
		1066	}
875		1067
		1068	BEGIN { AnyEvent::common_sense }
		1069
876	use Carp;	1070	use Carp ();
877		1071
878	our $VERSION = 4.35;	1072	our $VERSION = 4.86;
879	our $MODEL;	1073	our $MODEL;
880		1074
881	our $AUTOLOAD;	1075	our $AUTOLOAD;
882	our @ISA;	1076	our @ISA;
883		1077
884	our @REGISTRY;	1078	our @REGISTRY;
885		1079
886	our $WIN32;	1080	our $WIN32;
887		1081
		1082	our $VERBOSE;
		1083
888	BEGIN {	1084	BEGIN {
889	my $win32 = ! ! ($^O =~ /mswin32/i);	1085	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
890	eval "sub WIN32(){ $win32 }";	1086	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
891	}
892		1087
		1088	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1089	if ${^TAINT};
		1090
893	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1091	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1092
		1093	}
		1094
		1095	our $MAX_SIGNAL_LATENCY = 10;
894		1096
895	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1097	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
896		1098
897	{	1099	{
898	my $idx;	1100	my $idx;
…		…
906	[Event:: => AnyEvent::Impl::Event::],	1108	[Event:: => AnyEvent::Impl::Event::],
907	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1109	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
908	# everything below here will not be autoprobed	1110	# everything below here will not be autoprobed
909	# as the pureperl backend should work everywhere	1111	# as the pureperl backend should work everywhere
910	# and is usually faster	1112	# and is usually faster
911	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
912	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1113	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
913	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1114	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1115	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
914	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1116	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
915	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1117	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
916	[Wx:: => AnyEvent::Impl::POE::],	1118	[Wx:: => AnyEvent::Impl::POE::],
917	[Prima:: => AnyEvent::Impl::POE::],	1119	[Prima:: => AnyEvent::Impl::POE::],
		1120	# IO::Async is just too broken - we would need workarounds for its
		1121	# byzantine signal and broken child handling, among others.
		1122	# IO::Async is rather hard to detect, as it doesn't have any
		1123	# obvious default class.
		1124	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1125	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1126	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
918	);	1127	);
919		1128
920	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1129	our %method = map +($_ => 1),
		1130	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
921		1131
922	our @post_detect;	1132	our @post_detect;
923		1133
924	sub post_detect(&) {	1134	sub post_detect(&) {
925	my ($cb) = @_;	1135	my ($cb) = @_;
…		…
930	1	1140	1
931	} else {	1141	} else {
932	push @post_detect, $cb;	1142	push @post_detect, $cb;
933		1143
934	defined wantarray	1144	defined wantarray
935	? bless \$cb, "AnyEvent::Util::PostDetect"	1145	? bless \$cb, "AnyEvent::Util::postdetect"
936	: ()	1146	: ()
937	}	1147	}
938	}	1148	}
939		1149
940	sub AnyEvent::Util::PostDetect::DESTROY {	1150	sub AnyEvent::Util::postdetect::DESTROY {
941	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1151	@post_detect = grep $_ != ${$_[0]}, @post_detect;
942	}	1152	}
943		1153
944	sub detect() {	1154	sub detect() {
945	unless ($MODEL) {	1155	unless ($MODEL) {
946	no strict 'refs';
947	local $SIG{__DIE__};	1156	local $SIG{__DIE__};
948		1157
949	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1158	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
950	my $model = "AnyEvent::Impl::$1";	1159	my $model = "AnyEvent::Impl::$1";
951	if (eval "require $model") {	1160	if (eval "require $model") {
952	$MODEL = $model;	1161	$MODEL = $model;
953	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1162	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
954	} else {	1163	} else {
955	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1164	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
956	}	1165	}
957	}	1166	}
958		1167
959	# check for already loaded models	1168	# check for already loaded models
960	unless ($MODEL) {	1169	unless ($MODEL) {
961	for (@REGISTRY, @models) {	1170	for (@REGISTRY, @models) {
962	my ($package, $model) = @$_;	1171	my ($package, $model) = @$_;
963	if (${"$package\::VERSION"} > 0) {	1172	if (${"$package\::VERSION"} > 0) {
964	if (eval "require $model") {	1173	if (eval "require $model") {
965	$MODEL = $model;	1174	$MODEL = $model;
966	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1175	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
967	last;	1176	last;
968	}	1177	}
969	}	1178	}
970	}	1179	}
971		1180
…		…
976	my ($package, $model) = @$_;	1185	my ($package, $model) = @$_;
977	if (eval "require $package"	1186	if (eval "require $package"
978	and ${"$package\::VERSION"} > 0	1187	and ${"$package\::VERSION"} > 0
979	and eval "require $model") {	1188	and eval "require $model") {
980	$MODEL = $model;	1189	$MODEL = $model;
981	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1190	warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
982	last;	1191	last;
983	}	1192	}
984	}	1193	}
985		1194
986	$MODEL	1195	$MODEL
987	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1196	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
988	}	1197	}
989	}	1198	}
990		1199
991	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1200	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
992		1201
…		…
1002		1211
1003	sub AUTOLOAD {	1212	sub AUTOLOAD {
1004	(my $func = $AUTOLOAD) =~ s/.*://;	1213	(my $func = $AUTOLOAD) =~ s/.*://;
1005		1214
1006	$method{$func}	1215	$method{$func}
1007	or croak "$func: not a valid method for AnyEvent objects";	1216	or Carp::croak "$func: not a valid method for AnyEvent objects";
1008		1217
1009	detect unless $MODEL;	1218	detect unless $MODEL;
1010		1219
1011	my $class = shift;	1220	my $class = shift;
1012	$class->$func (@_);	1221	$class->$func (@_);
1013	}	1222	}
1014		1223
1015	# utility function to dup a filehandle. this is used by many backends	1224	# utility function to dup a filehandle. this is used by many backends
1016	# to support binding more than one watcher per filehandle (they usually	1225	# to support binding more than one watcher per filehandle (they usually
1017	# allow only one watcher per fd, so we dup it to get a different one).	1226	# allow only one watcher per fd, so we dup it to get a different one).
1018	sub _dupfh($$$$) {	1227	sub _dupfh($$;$$) {
1019	my ($poll, $fh, $r, $w) = @_;	1228	my ($poll, $fh, $r, $w) = @_;
1020		1229
1021	# cygwin requires the fh mode to be matching, unix doesn't	1230	# cygwin requires the fh mode to be matching, unix doesn't
1022	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1231	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1023	: $poll eq "w" ? ($w, ">")
1024	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1025		1232
1026	open my $fh2, "$mode&" . fileno $fh	1233	open my $fh2, $mode, $fh
1027	or die "cannot dup() filehandle: $!";	1234	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1028		1235
1029	# we assume CLOEXEC is already set by perl in all important cases	1236	# we assume CLOEXEC is already set by perl in all important cases
1030		1237
1031	($fh2, $rw)	1238	($fh2, $rw)
1032	}	1239	}
1033		1240
1034	package AnyEvent::Base;	1241	package AnyEvent::Base;
1035		1242
1036	# default implementation for now and time	1243	# default implementations for many methods
1037		1244
1038	BEGIN {	1245	sub _time {
		1246	# probe for availability of Time::HiRes
1039	if (eval "use Time::HiRes (); time (); 1") {	1247	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1248	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1040	*_time = \&Time::HiRes::time;	1249	*_time = \&Time::HiRes::time;
1041	# if (eval "use POSIX (); (POSIX::times())...	1250	# if (eval "use POSIX (); (POSIX::times())...
1042	} else {	1251	} else {
		1252	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1043	*_time = sub { time }; # epic fail	1253	*_time = sub { time }; # epic fail
1044	}	1254	}
		1255
		1256	&_time
1045	}	1257	}
1046		1258
1047	sub time { _time }	1259	sub time { _time }
1048	sub now { _time }	1260	sub now { _time }
		1261	sub now_update { }
1049		1262
1050	# default implementation for ->condvar	1263	# default implementation for ->condvar
1051		1264
1052	sub condvar {	1265	sub condvar {
1053	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1266	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1054	}	1267	}
1055		1268
1056	# default implementation for ->signal	1269	# default implementation for ->signal
1057		1270
		1271	our $HAVE_ASYNC_INTERRUPT;
1058	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1272	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1273	our (%SIG_ASY, %SIG_ASY_W);
		1274	our ($SIG_COUNT, $SIG_TW);
1059		1275
1060	sub _signal_exec {	1276	sub _signal_exec {
		1277	$HAVE_ASYNC_INTERRUPT
		1278	? $SIGPIPE_R->drain
1061	sysread $SIGPIPE_R, my $dummy, 4;	1279	: sysread $SIGPIPE_R, my $dummy, 9;
1062		1280
1063	while (%SIG_EV) {	1281	while (%SIG_EV) {
1064	for (keys %SIG_EV) {	1282	for (keys %SIG_EV) {
1065	delete $SIG_EV{$_};	1283	delete $SIG_EV{$_};
1066	$_->() for values %{ $SIG_CB{$_} || {} };	1284	$_->() for values %{ $SIG_CB{$_} || {} };
1067	}	1285	}
1068	}	1286	}
1069	}	1287	}
1070		1288
		1289	# install a dumym wakeupw atcher to reduce signal catching latency
		1290	sub _sig_add() {
		1291	unless ($SIG_COUNT++) {
		1292	# try to align timer on a full-second boundary, if possible
		1293	my $NOW = AnyEvent->now;
		1294
		1295	$SIG_TW = AnyEvent->timer (
		1296	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1297	interval => $MAX_SIGNAL_LATENCY,
		1298	cb => sub { }, # just for the PERL_ASYNC_CHECK
		1299	);
		1300	}
		1301	}
		1302
		1303	sub _sig_del {
		1304	undef $SIG_TW
		1305	unless --$SIG_COUNT;
		1306	}
		1307
		1308	sub _signal {
		1309	my (undef, %arg) = @_;
		1310
		1311	my $signal = uc $arg{signal}
		1312	or Carp::croak "required option 'signal' is missing";
		1313
		1314	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1315
		1316	if ($HAVE_ASYNC_INTERRUPT) {
		1317	# async::interrupt
		1318
		1319	$SIG_ASY{$signal} ||= do {
		1320	my $asy = new Async::Interrupt
		1321	cb => sub { undef $SIG_EV{$signal} },
		1322	signal => $signal,
		1323	pipe => [$SIGPIPE_R->filenos],
		1324	;
		1325	$asy->pipe_autodrain (0);
		1326
		1327	$asy
		1328	};
		1329
		1330	} else {
		1331	# pure perl
		1332
		1333	$SIG{$signal} ||= sub {
		1334	local $!;
		1335	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1336	undef $SIG_EV{$signal};
		1337	};
		1338
		1339	# can't do signal processing without introducing races in pure perl,
		1340	# so limit the signal latency.
		1341	_sig_add;
		1342	}
		1343
		1344	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1345	}
		1346
1071	sub signal {	1347	sub signal {
1072	my (undef, %arg) = @_;	1348	# probe for availability of Async::Interrupt
		1349	if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
		1350	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1073		1351
1074	unless ($SIGPIPE_R) {	1352	$HAVE_ASYNC_INTERRUPT = 1;
		1353	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1354	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
		1355
		1356	} else {
		1357	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1358
1075	require Fcntl;	1359	require Fcntl;
1076		1360
1077	if (AnyEvent::WIN32) {	1361	if (AnyEvent::WIN32) {
1078	require AnyEvent::Util;	1362	require AnyEvent::Util;
1079		1363
…		…
1082	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case	1366	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1083	} else {	1367	} else {
1084	pipe $SIGPIPE_R, $SIGPIPE_W;	1368	pipe $SIGPIPE_R, $SIGPIPE_W;
1085	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1369	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1086	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1370	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1371
		1372	# not strictly required, as $^F is normally 2, but let's make sure...
		1373	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1374	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1087	}	1375	}
1088		1376
1089	$SIGPIPE_R	1377	$SIGPIPE_R
1090	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1378	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1091		1379
1092	# not strictly required, as $^F is normally 2, but let's make sure...
1093	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1094	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1095
1096	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1380	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1097	}	1381	}
1098		1382
1099	my $signal = uc $arg{signal}	1383	*signal = \&_signal;
1100	or Carp::croak "required option 'signal' is missing";	1384	&signal
1101
1102	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1103	$SIG{$signal} ||= sub {
1104	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1105	undef $SIG_EV{$signal};
1106	};
1107
1108	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
1109	}	1385	}
1110		1386
1111	sub AnyEvent::Base::Signal::DESTROY {	1387	sub AnyEvent::Base::signal::DESTROY {
1112	my ($signal, $cb) = @{$_[0]};	1388	my ($signal, $cb) = @{$_[0]};
1113		1389
		1390	_sig_del;
		1391
1114	delete $SIG_CB{$signal}{$cb};	1392	delete $SIG_CB{$signal}{$cb};
1115		1393
		1394	$HAVE_ASYNC_INTERRUPT
		1395	? delete $SIG_ASY{$signal}
		1396	: # delete doesn't work with older perls - they then
		1397	# print weird messages, or just unconditionally exit
		1398	# instead of getting the default action.
		1399	undef $SIG{$signal}
1116	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };	1400	unless keys %{ $SIG_CB{$signal} };
1117	}	1401	}
1118		1402
1119	# default implementation for ->child	1403	# default implementation for ->child
1120		1404
1121	our %PID_CB;	1405	our %PID_CB;
1122	our $CHLD_W;	1406	our $CHLD_W;
1123	our $CHLD_DELAY_W;	1407	our $CHLD_DELAY_W;
1124	our $PID_IDLE;
1125	our $WNOHANG;	1408	our $WNOHANG;
1126		1409
1127	sub _child_wait {	1410	sub _sigchld {
1128	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1411	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
		1412	$_->($pid, $?)
1129	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1413	for values %{ $PID_CB{$pid} || {} },
1130	(values %{ $PID_CB{0} || {} });	1414	values %{ $PID_CB{0} || {} };
1131	}	1415	}
1132
1133	undef $PID_IDLE;
1134	}
1135
1136	sub _sigchld {
1137	# make sure we deliver these changes "synchronous" with the event loop.
1138	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
1139	undef $CHLD_DELAY_W;
1140	&_child_wait;
1141	});
1142	}	1416	}
1143		1417
1144	sub child {	1418	sub child {
1145	my (undef, %arg) = @_;	1419	my (undef, %arg) = @_;
1146		1420
1147	defined (my $pid = $arg{pid} + 0)	1421	defined (my $pid = $arg{pid} + 0)
1148	or Carp::croak "required option 'pid' is missing";	1422	or Carp::croak "required option 'pid' is missing";
1149		1423
1150	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1424	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1151		1425
1152	unless ($WNOHANG) {	1426	# WNOHANG is almost cetrainly 1 everywhere
		1427	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1428	? 1
1153	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1429	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1154	}
1155		1430
1156	unless ($CHLD_W) {	1431	unless ($CHLD_W) {
1157	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1432	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1158	# child could be a zombie already, so make at least one round	1433	# child could be a zombie already, so make at least one round
1159	&_sigchld;	1434	&_sigchld;
1160	}	1435	}
1161		1436
1162	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1437	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1163	}	1438	}
1164		1439
1165	sub AnyEvent::Base::Child::DESTROY {	1440	sub AnyEvent::Base::child::DESTROY {
1166	my ($pid, $cb) = @{$_[0]};	1441	my ($pid, $cb) = @{$_[0]};
1167		1442
1168	delete $PID_CB{$pid}{$cb};	1443	delete $PID_CB{$pid}{$cb};
1169	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1444	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1170		1445
1171	undef $CHLD_W unless keys %PID_CB;	1446	undef $CHLD_W unless keys %PID_CB;
1172	}	1447	}
1173		1448
		1449	# idle emulation is done by simply using a timer, regardless
		1450	# of whether the process is idle or not, and not letting
		1451	# the callback use more than 50% of the time.
		1452	sub idle {
		1453	my (undef, %arg) = @_;
		1454
		1455	my ($cb, $w, $rcb) = $arg{cb};
		1456
		1457	$rcb = sub {
		1458	if ($cb) {
		1459	$w = _time;
		1460	&$cb;
		1461	$w = _time - $w;
		1462
		1463	# never use more then 50% of the time for the idle watcher,
		1464	# within some limits
		1465	$w = 0.0001 if $w < 0.0001;
		1466	$w = 5 if $w > 5;
		1467
		1468	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1469	} else {
		1470	# clean up...
		1471	undef $w;
		1472	undef $rcb;
		1473	}
		1474	};
		1475
		1476	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1477
		1478	bless \\$cb, "AnyEvent::Base::idle"
		1479	}
		1480
		1481	sub AnyEvent::Base::idle::DESTROY {
		1482	undef $${$_[0]};
		1483	}
		1484
1174	package AnyEvent::CondVar;	1485	package AnyEvent::CondVar;
1175		1486
1176	our @ISA = AnyEvent::CondVar::Base::;	1487	our @ISA = AnyEvent::CondVar::Base::;
1177		1488
1178	package AnyEvent::CondVar::Base;	1489	package AnyEvent::CondVar::Base;
1179		1490
1180	use overload	1491	#use overload
1181	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1492	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1182	fallback => 1;	1493	# fallback => 1;
		1494
		1495	# save 300+ kilobytes by dirtily hardcoding overloading
		1496	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1497	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1498	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1499	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1500
		1501	our $WAITING;
1183		1502
1184	sub _send {	1503	sub _send {
1185	# nop	1504	# nop
1186	}	1505	}
1187		1506
…		…
1200	sub ready {	1519	sub ready {
1201	$_[0]{_ae_sent}	1520	$_[0]{_ae_sent}
1202	}	1521	}
1203		1522
1204	sub _wait {	1523	sub _wait {
		1524	$WAITING
		1525	and !$_[0]{_ae_sent}
		1526	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1527
		1528	local $WAITING = 1;
1205	AnyEvent->one_event while !$_[0]{_ae_sent};	1529	AnyEvent->one_event while !$_[0]{_ae_sent};
1206	}	1530	}
1207		1531
1208	sub recv {	1532	sub recv {
1209	$_[0]->_wait;	1533	$_[0]->_wait;
…		…
1250	so on.	1574	so on.
1251		1575
1252	=head1 ENVIRONMENT VARIABLES	1576	=head1 ENVIRONMENT VARIABLES
1253		1577
1254	The following environment variables are used by this module or its	1578	The following environment variables are used by this module or its
1255	submodules:	1579	submodules.
		1580
		1581	Note that AnyEvent will remove I<all> environment variables starting with
		1582	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1583	enabled.
1256		1584
1257	=over 4	1585	=over 4
1258		1586
1259	=item C<PERL_ANYEVENT_VERBOSE>	1587	=item C<PERL_ANYEVENT_VERBOSE>
1260		1588
…		…
1267	C<PERL_ANYEVENT_MODEL>.	1595	C<PERL_ANYEVENT_MODEL>.
1268		1596
1269	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1597	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1270	model it chooses.	1598	model it chooses.
1271		1599
		1600	When set to C<8> or higher, then AnyEvent will report extra information on
		1601	which optional modules it loads and how it implements certain features.
		1602
1272	=item C<PERL_ANYEVENT_STRICT>	1603	=item C<PERL_ANYEVENT_STRICT>
1273		1604
1274	AnyEvent does not do much argument checking by default, as thorough	1605	AnyEvent does not do much argument checking by default, as thorough
1275	argument checking is very costly. Setting this variable to a true value	1606	argument checking is very costly. Setting this variable to a true value
1276	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1607	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1277	check the arguments passed to most method calls. If it finds any problems	1608	check the arguments passed to most method calls. If it finds any problems,
1278	it will croak.	1609	it will croak.
1279		1610
1280	In other words, enables "strict" mode.	1611	In other words, enables "strict" mode.
1281		1612
1282	Unlike C<use strict>, it is definitely recommended ot keep it off in	1613	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1283	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1614	>>, it is definitely recommended to keep it off in production. Keeping
1284	developing programs can be very useful, however.	1615	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1616	can be very useful, however.
1285		1617
1286	=item C<PERL_ANYEVENT_MODEL>	1618	=item C<PERL_ANYEVENT_MODEL>
1287		1619
1288	This can be used to specify the event model to be used by AnyEvent, before	1620	This can be used to specify the event model to be used by AnyEvent, before
1289	auto detection and -probing kicks in. It must be a string consisting	1621	auto detection and -probing kicks in. It must be a string consisting
…		…
1332		1664
1333	=item C<PERL_ANYEVENT_MAX_FORKS>	1665	=item C<PERL_ANYEVENT_MAX_FORKS>
1334		1666
1335	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1667	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1336	will create in parallel.	1668	will create in parallel.
		1669
		1670	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1671
		1672	The default value for the C<max_outstanding> parameter for the default DNS
		1673	resolver - this is the maximum number of parallel DNS requests that are
		1674	sent to the DNS server.
		1675
		1676	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1677
		1678	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1679	configuration) in the default resolver. When set to the empty string, no
		1680	default config will be used.
		1681
		1682	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1683
		1684	When neither C<ca_file> nor C<ca_path> was specified during
		1685	L<AnyEvent::TLS> context creation, and either of these environment
		1686	variables exist, they will be used to specify CA certificate locations
		1687	instead of a system-dependent default.
		1688
		1689	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1690
		1691	When these are set to C<1>, then the respective modules are not
		1692	loaded. Mostly good for testing AnyEvent itself.
1337		1693
1338	=back	1694	=back
1339		1695
1340	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1696	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1341		1697
…		…
1586	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	1942	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1587	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	1943	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1588	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	1944	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1589	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	1945	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1590	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	1946	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		1947	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		1948	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1591	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	1949	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1592	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	1950	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1593	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	1951	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1594	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	1952	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1595		1953
…		…
1624	performance becomes really bad with lots of file descriptors (and few of	1982	performance becomes really bad with lots of file descriptors (and few of
1625	them active), of course, but this was not subject of this benchmark.	1983	them active), of course, but this was not subject of this benchmark.
1626		1984
1627	The C<Event> module has a relatively high setup and callback invocation	1985	The C<Event> module has a relatively high setup and callback invocation
1628	cost, but overall scores in on the third place.	1986	cost, but overall scores in on the third place.
		1987
		1988	C<IO::Async> performs admirably well, about on par with C<Event>, even
		1989	when using its pure perl backend.
1629		1990
1630	C<Glib>'s memory usage is quite a bit higher, but it features a	1991	C<Glib>'s memory usage is quite a bit higher, but it features a
1631	faster callback invocation and overall ends up in the same class as	1992	faster callback invocation and overall ends up in the same class as
1632	C<Event>. However, Glib scales extremely badly, doubling the number of	1993	C<Event>. However, Glib scales extremely badly, doubling the number of
1633	watchers increases the processing time by more than a factor of four,	1994	watchers increases the processing time by more than a factor of four,
…		…
1711	it to another server. This includes deleting the old timeout and creating	2072	it to another server. This includes deleting the old timeout and creating
1712	a new one that moves the timeout into the future.	2073	a new one that moves the timeout into the future.
1713		2074
1714	=head3 Results	2075	=head3 Results
1715		2076
1716	name sockets create request	2077	name sockets create request
1717	EV 20000 69.01 11.16	2078	EV 20000 69.01 11.16
1718	Perl 20000 73.32 35.87	2079	Perl 20000 73.32 35.87
		2080	IOAsync 20000 157.00 98.14 epoll
		2081	IOAsync 20000 159.31 616.06 poll
1719	Event 20000 212.62 257.32	2082	Event 20000 212.62 257.32
1720	Glib 20000 651.16 1896.30	2083	Glib 20000 651.16 1896.30
1721	POE 20000 349.67 12317.24 uses POE::Loop::Event	2084	POE 20000 349.67 12317.24 uses POE::Loop::Event
1722		2085
1723	=head3 Discussion	2086	=head3 Discussion
1724		2087
1725	This benchmark I<does> measure scalability and overall performance of the	2088	This benchmark I<does> measure scalability and overall performance of the
1726	particular event loop.	2089	particular event loop.
…		…
1728	EV is again fastest. Since it is using epoll on my system, the setup time	2091	EV is again fastest. Since it is using epoll on my system, the setup time
1729	is relatively high, though.	2092	is relatively high, though.
1730		2093
1731	Perl surprisingly comes second. It is much faster than the C-based event	2094	Perl surprisingly comes second. It is much faster than the C-based event
1732	loops Event and Glib.	2095	loops Event and Glib.
		2096
		2097	IO::Async performs very well when using its epoll backend, and still quite
		2098	good compared to Glib when using its pure perl backend.
1733		2099
1734	Event suffers from high setup time as well (look at its code and you will	2100	Event suffers from high setup time as well (look at its code and you will
1735	understand why). Callback invocation also has a high overhead compared to	2101	understand why). Callback invocation also has a high overhead compared to
1736	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2102	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1737	uses select or poll in basically all documented configurations.	2103	uses select or poll in basically all documented configurations.
…		…
1800	=item * C-based event loops perform very well with small number of	2166	=item * C-based event loops perform very well with small number of
1801	watchers, as the management overhead dominates.	2167	watchers, as the management overhead dominates.
1802		2168
1803	=back	2169	=back
1804		2170
		2171	=head2 THE IO::Lambda BENCHMARK
		2172
		2173	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2174	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2175	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2176	shouldn't come as a surprise to anybody). As such, the benchmark is
		2177	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2178	very optimal. But how would AnyEvent compare when used without the extra
		2179	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2180
		2181	The benchmark itself creates an echo-server, and then, for 500 times,
		2182	connects to the echo server, sends a line, waits for the reply, and then
		2183	creates the next connection. This is a rather bad benchmark, as it doesn't
		2184	test the efficiency of the framework or much non-blocking I/O, but it is a
		2185	benchmark nevertheless.
		2186
		2187	name runtime
		2188	Lambda/select 0.330 sec
		2189	+ optimized 0.122 sec
		2190	Lambda/AnyEvent 0.327 sec
		2191	+ optimized 0.138 sec
		2192	Raw sockets/select 0.077 sec
		2193	POE/select, components 0.662 sec
		2194	POE/select, raw sockets 0.226 sec
		2195	POE/select, optimized 0.404 sec
		2196
		2197	AnyEvent/select/nb 0.085 sec
		2198	AnyEvent/EV/nb 0.068 sec
		2199	+state machine 0.134 sec
		2200
		2201	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2202	benchmarks actually make blocking connects and use 100% blocking I/O,
		2203	defeating the purpose of an event-based solution. All of the newly
		2204	written AnyEvent benchmarks use 100% non-blocking connects (using
		2205	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2206	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2207	generally require a lot more bookkeeping and event handling than blocking
		2208	connects (which involve a single syscall only).
		2209
		2210	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2211	offers similar expressive power as POE and IO::Lambda, using conventional
		2212	Perl syntax. This means that both the echo server and the client are 100%
		2213	non-blocking, further placing it at a disadvantage.
		2214
		2215	As you can see, the AnyEvent + EV combination even beats the
		2216	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2217	backend easily beats IO::Lambda and POE.
		2218
		2219	And even the 100% non-blocking version written using the high-level (and
		2220	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2221	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2222	in a non-blocking way.
		2223
		2224	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2225	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2226	part of the IO::lambda distribution and were used without any changes.
		2227
1805		2228
1806	=head1 SIGNALS	2229	=head1 SIGNALS
1807		2230
1808	AnyEvent currently installs handlers for these signals:	2231	AnyEvent currently installs handlers for these signals:
1809		2232
…		…
1812	=item SIGCHLD	2235	=item SIGCHLD
1813		2236
1814	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2237	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1815	emulation for event loops that do not support them natively. Also, some	2238	emulation for event loops that do not support them natively. Also, some
1816	event loops install a similar handler.	2239	event loops install a similar handler.
		2240
		2241	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2242	AnyEvent will reset it to default, to avoid losing child exit statuses.
1817		2243
1818	=item SIGPIPE	2244	=item SIGPIPE
1819		2245
1820	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2246	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1821	when AnyEvent gets loaded.	2247	when AnyEvent gets loaded.
…		…
1833		2259
1834	=back	2260	=back
1835		2261
1836	=cut	2262	=cut
1837		2263
		2264	undef $SIG{CHLD}
		2265	if $SIG{CHLD} eq 'IGNORE';
		2266
1838	$SIG{PIPE} = sub { }	2267	$SIG{PIPE} = sub { }
1839	unless defined $SIG{PIPE};	2268	unless defined $SIG{PIPE};
		2269
		2270	=head1 RECOMMENDED/OPTIONAL MODULES
		2271
		2272	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2273	it's built-in modules) are required to use it.
		2274
		2275	That does not mean that AnyEvent won't take advantage of some additional
		2276	modules if they are installed.
		2277
		2278	This section epxlains which additional modules will be used, and how they
		2279	affect AnyEvent's operetion.
		2280
		2281	=over 4
		2282
		2283	=item L<Async::Interrupt>
		2284
		2285	This slightly arcane module is used to implement fast signal handling: To
		2286	my knowledge, there is no way to do completely race-free and quick
		2287	signal handling in pure perl. To ensure that signals still get
		2288	delivered, AnyEvent will start an interval timer to wake up perl (and
		2289	catch the signals) with some delay (default is 10 seconds, look for
		2290	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2291
		2292	If this module is available, then it will be used to implement signal
		2293	catching, which means that signals will not be delayed, and the event loop
		2294	will not be interrupted regularly, which is more efficient (And good for
		2295	battery life on laptops).
		2296
		2297	This affects not just the pure-perl event loop, but also other event loops
		2298	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2299
		2300	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2301	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2302	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2303	does nothing for those backends.
		2304
		2305	=item L<EV>
		2306
		2307	This module isn't really "optional", as it is simply one of the backend
		2308	event loops that AnyEvent can use. However, it is simply the best event
		2309	loop available in terms of features, speed and stability: It supports
		2310	the AnyEvent API optimally, implements all the watcher types in XS, does
		2311	automatic timer adjustments even when no monotonic clock is available,
		2312	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2313	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2314	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2315
		2316	=item L<Guard>
		2317
		2318	The guard module, when used, will be used to implement
		2319	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2320	lot less memory), but otherwise doesn't affect guard operation much. It is
		2321	purely used for performance.
		2322
		2323	=item L<JSON> and L<JSON::XS>
		2324
		2325	This module is required when you want to read or write JSON data via
		2326	L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2327	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2328
		2329	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2330	installed.
		2331
		2332	=item L<Net::SSLeay>
		2333
		2334	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2335	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2336	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2337
		2338	=item L<Time::HiRes>
		2339
		2340	This module is part of perl since release 5.008. It will be used when the
		2341	chosen event library does not come with a timing source on it's own. The
		2342	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2343	try to use a monotonic clock for timing stability.
		2344
		2345	=back
1840		2346
1841		2347
1842	=head1 FORK	2348	=head1 FORK
1843		2349
1844	Most event libraries are not fork-safe. The ones who are usually are	2350	Most event libraries are not fork-safe. The ones who are usually are
1845	because they rely on inefficient but fork-safe C<select> or C<poll>	2351	because they rely on inefficient but fork-safe C<select> or C<poll>
1846	calls. Only L<EV> is fully fork-aware.	2352	calls. Only L<EV> is fully fork-aware.
1847		2353
1848	If you have to fork, you must either do so I<before> creating your first	2354	If you have to fork, you must either do so I<before> creating your first
1849	watcher OR you must not use AnyEvent at all in the child.	2355	watcher OR you must not use AnyEvent at all in the child OR you must do
		2356	something completely out of the scope of AnyEvent.
1850		2357
1851		2358
1852	=head1 SECURITY CONSIDERATIONS	2359	=head1 SECURITY CONSIDERATIONS
1853		2360
1854	AnyEvent can be forced to load any event model via	2361	AnyEvent can be forced to load any event model via
…		…
1866	use AnyEvent;	2373	use AnyEvent;
1867		2374
1868	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2375	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1869	be used to probe what backend is used and gain other information (which is	2376	be used to probe what backend is used and gain other information (which is
1870	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2377	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1871	$ENV{PERL_ANYEGENT_STRICT}.	2378	$ENV{PERL_ANYEVENT_STRICT}.
		2379
		2380	Note that AnyEvent will remove I<all> environment variables starting with
		2381	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2382	enabled.
1872		2383
1873		2384
1874	=head1 BUGS	2385	=head1 BUGS
1875		2386
1876	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2387	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
…		…
1888	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2399	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1889		2400
1890	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2401	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1891	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2402	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1892	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2403	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1893	L<AnyEvent::Impl::POE>.	2404	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.
1894		2405
1895	Non-blocking file handles, sockets, TCP clients and	2406	Non-blocking file handles, sockets, TCP clients and
1896	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2407	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1897		2408
1898	Asynchronous DNS: L<AnyEvent::DNS>.	2409	Asynchronous DNS: L<AnyEvent::DNS>.
1899		2410
1900	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2411	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2412	L<Coro::Event>,
1901		2413
1902	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2414	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2415	L<AnyEvent::HTTP>.
1903		2416
1904		2417
1905	=head1 AUTHOR	2418	=head1 AUTHOR
1906		2419
1907	Marc Lehmann <schmorp@schmorp.de>	2420	Marc Lehmann <schmorp@schmorp.de>

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