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Revision 1.287 by root, Tue Aug 25 12:05:30 2009 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
6	event loops.	6	and POE are various supported event loops/environments.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
…		…
40	=head1 INTRODUCTION/TUTORIAL	40	=head1 INTRODUCTION/TUTORIAL
41		41
42	This manpage is mainly a reference manual. If you are interested	42	This manpage is mainly a reference manual. If you are interested
43	in a tutorial or some gentle introduction, have a look at the	43	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	44	L<AnyEvent::Intro> manpage.
		45
		46	=head1 SUPPORT
		47
		48	There is a mailinglist for discussing all things AnyEvent, and an IRC
		49	channel, too.
		50
		51	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		52	Repository>, at L<http://anyevent.schmorp.de>, for more info.
45		53
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	54	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		55
48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	56	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49	nowadays. So what is different about AnyEvent?	57	nowadays. So what is different about AnyEvent?
…		…
173	my variables are only visible after the statement in which they are	181	my variables are only visible after the statement in which they are
174	declared.	182	declared.
175		183
176	=head2 I/O WATCHERS	184	=head2 I/O WATCHERS
177		185
		186	$w = AnyEvent->io (
		187	fh => <filehandle_or_fileno>,
		188	poll => <"r" or "w">,
		189	cb => <callback>,
		190	);
		191
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	192	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	193	with the following mandatory key-value pairs as arguments:
180		194
181	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch	195	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
182	for events (AnyEvent might or might not keep a reference to this file	196	for events (AnyEvent might or might not keep a reference to this file
183	handle). Note that only file handles pointing to things for which	197	handle). Note that only file handles pointing to things for which
184	non-blocking operation makes sense are allowed. This includes sockets,	198	non-blocking operation makes sense are allowed. This includes sockets,
185	most character devices, pipes, fifos and so on, but not for example files	199	most character devices, pipes, fifos and so on, but not for example files
186	or block devices.	200	or block devices.
…		…
211	undef $w;	225	undef $w;
212	});	226	});
213		227
214	=head2 TIME WATCHERS	228	=head2 TIME WATCHERS
215		229
		230	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		231
		232	$w = AnyEvent->timer (
		233	after => <fractional_seconds>,
		234	interval => <fractional_seconds>,
		235	cb => <callback>,
		236	);
		237
216	You can create a time watcher by calling the C<< AnyEvent->timer >>	238	You can create a time watcher by calling the C<< AnyEvent->timer >>
217	method with the following mandatory arguments:	239	method with the following mandatory arguments:
218		240
219	C<after> specifies after how many seconds (fractional values are	241	C<after> specifies after how many seconds (fractional values are
220	supported) the callback should be invoked. C<cb> is the callback to invoke	242	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
347		369
348	=back	370	=back
349		371
350	=head2 SIGNAL WATCHERS	372	=head2 SIGNAL WATCHERS
351		373
		374	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
		375
352	You can watch for signals using a signal watcher, C<signal> is the signal	376	You can watch for signals using a signal watcher, C<signal> is the signal
353	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	377	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354	callback to be invoked whenever a signal occurs.	378	callback to be invoked whenever a signal occurs.
355		379
356	Although the callback might get passed parameters, their value and	380	Although the callback might get passed parameters, their value and
…		…
361	invocation, and callback invocation will be synchronous. Synchronous means	385	invocation, and callback invocation will be synchronous. Synchronous means
362	that it might take a while until the signal gets handled by the process,	386	that it might take a while until the signal gets handled by the process,
363	but it is guaranteed not to interrupt any other callbacks.	387	but it is guaranteed not to interrupt any other callbacks.
364		388
365	The main advantage of using these watchers is that you can share a signal	389	The main advantage of using these watchers is that you can share a signal
366	between multiple watchers.	390	between multiple watchers, and AnyEvent will ensure that signals will not
		391	interrupt your program at bad times.
367		392
368	This watcher might use C<%SIG>, so programs overwriting those signals	393	This watcher might use C<%SIG> (depending on the event loop used),
369	directly will likely not work correctly.	394	so programs overwriting those signals directly will likely not work
		395	correctly.
370		396
371	Example: exit on SIGINT	397	Example: exit on SIGINT
372		398
373	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	399	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
374		400
		401	=head3 Signal Races, Delays and Workarounds
		402
		403	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		404	callbacks to signals in a generic way, which is a pity, as you cannot
		405	do race-free signal handling in perl, requiring C libraries for
		406	this. AnyEvent will try to do it's best, which means in some cases,
		407	signals will be delayed. The maximum time a signal might be delayed is
		408	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		409	variable can be changed only before the first signal watcher is created,
		410	and should be left alone otherwise. This variable determines how often
		411	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		412	will cause fewer spurious wake-ups, which is better for power and CPU
		413	saving.
		414
		415	All these problems can be avoided by installing the optional
		416	L<Async::Interrupt> module, which works with most event loops. It will not
		417	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		418	(and not with L<POE> currently, as POE does it's own workaround with
		419	one-second latency). For those, you just have to suffer the delays.
		420
375	=head2 CHILD PROCESS WATCHERS	421	=head2 CHILD PROCESS WATCHERS
376		422
		423	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		424
377	You can also watch on a child process exit and catch its exit status.	425	You can also watch on a child process exit and catch its exit status.
378		426
379	The child process is specified by the C<pid> argument (if set to C<0>, it	427	The child process is specified by the C<pid> argument (one some backends,
380	watches for any child process exit). The watcher will triggered only when	428	using C<0> watches for any child process exit, on others this will
381	the child process has finished and an exit status is available, not on	429	croak). The watcher will be triggered only when the child process has
382	any trace events (stopped/continued).	430	finished and an exit status is available, not on any trace events
		431	(stopped/continued).
383		432
384	The callback will be called with the pid and exit status (as returned by	433	The callback will be called with the pid and exit status (as returned by
385	waitpid), so unlike other watcher types, you I<can> rely on child watcher	434	waitpid), so unlike other watcher types, you I<can> rely on child watcher
386	callback arguments.	435	callback arguments.
387		436
…		…
392		441
393	There is a slight catch to child watchers, however: you usually start them	442	There is a slight catch to child watchers, however: you usually start them
394	I<after> the child process was created, and this means the process could	443	I<after> the child process was created, and this means the process could
395	have exited already (and no SIGCHLD will be sent anymore).	444	have exited already (and no SIGCHLD will be sent anymore).
396		445
397	Not all event models handle this correctly (POE doesn't), but even for	446	Not all event models handle this correctly (neither POE nor IO::Async do,
		447	see their AnyEvent::Impl manpages for details), but even for event models
398	event models that I<do> handle this correctly, they usually need to be	448	that I<do> handle this correctly, they usually need to be loaded before
399	loaded before the process exits (i.e. before you fork in the first place).	449	the process exits (i.e. before you fork in the first place). AnyEvent's
		450	pure perl event loop handles all cases correctly regardless of when you
		451	start the watcher.
400		452
401	This means you cannot create a child watcher as the very first thing in an	453	This means you cannot create a child watcher as the very first
402	AnyEvent program, you I<have> to create at least one watcher before you	454	thing in an AnyEvent program, you I<have> to create at least one
403	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	455	watcher before you C<fork> the child (alternatively, you can call
		456	C<AnyEvent::detect>).
		457
		458	As most event loops do not support waiting for child events, they will be
		459	emulated by AnyEvent in most cases, in which the latency and race problems
		460	mentioned in the description of signal watchers apply.
404		461
405	Example: fork a process and wait for it	462	Example: fork a process and wait for it
406		463
407	my $done = AnyEvent->condvar;	464	my $done = AnyEvent->condvar;
408		465
…		…
420	# do something else, then wait for process exit	477	# do something else, then wait for process exit
421	$done->recv;	478	$done->recv;
422		479
423	=head2 IDLE WATCHERS	480	=head2 IDLE WATCHERS
424		481
		482	$w = AnyEvent->idle (cb => <callback>);
		483
425	Sometimes there is a need to do something, but it is not so important	484	Sometimes there is a need to do something, but it is not so important
426	to do it instantly, but only when there is nothing better to do. This	485	to do it instantly, but only when there is nothing better to do. This
427	"nothing better to do" is usually defined to be "no other events need	486	"nothing better to do" is usually defined to be "no other events need
428	attention by the event loop".	487	attention by the event loop".
429		488
…		…
455	});	514	});
456	});	515	});
457		516
458	=head2 CONDITION VARIABLES	517	=head2 CONDITION VARIABLES
459		518
		519	$cv = AnyEvent->condvar;
		520
		521	$cv->send (<list>);
		522	my @res = $cv->recv;
		523
460	If you are familiar with some event loops you will know that all of them	524	If you are familiar with some event loops you will know that all of them
461	require you to run some blocking "loop", "run" or similar function that	525	require you to run some blocking "loop", "run" or similar function that
462	will actively watch for new events and call your callbacks.	526	will actively watch for new events and call your callbacks.
463		527
464	AnyEvent is different, it expects somebody else to run the event loop and	528	AnyEvent is slightly different: it expects somebody else to run the event
465	will only block when necessary (usually when told by the user).	529	loop and will only block when necessary (usually when told by the user).
466		530
467	The instrument to do that is called a "condition variable", so called	531	The instrument to do that is called a "condition variable", so called
468	because they represent a condition that must become true.	532	because they represent a condition that must become true.
469		533
		534	Now is probably a good time to look at the examples further below.
		535
470	Condition variables can be created by calling the C<< AnyEvent->condvar	536	Condition variables can be created by calling the C<< AnyEvent->condvar
471	>> method, usually without arguments. The only argument pair allowed is	537	>> method, usually without arguments. The only argument pair allowed is
472
473	C<cb>, which specifies a callback to be called when the condition variable	538	C<cb>, which specifies a callback to be called when the condition variable
474	becomes true, with the condition variable as the first argument (but not	539	becomes true, with the condition variable as the first argument (but not
475	the results).	540	the results).
476		541
477	After creation, the condition variable is "false" until it becomes "true"	542	After creation, the condition variable is "false" until it becomes "true"
…		…
482	Condition variables are similar to callbacks, except that you can	547	Condition variables are similar to callbacks, except that you can
483	optionally wait for them. They can also be called merge points - points	548	optionally wait for them. They can also be called merge points - points
484	in time where multiple outstanding events have been processed. And yet	549	in time where multiple outstanding events have been processed. And yet
485	another way to call them is transactions - each condition variable can be	550	another way to call them is transactions - each condition variable can be
486	used to represent a transaction, which finishes at some point and delivers	551	used to represent a transaction, which finishes at some point and delivers
487	a result.	552	a result. And yet some people know them as "futures" - a promise to
		553	compute/deliver something that you can wait for.
488		554
489	Condition variables are very useful to signal that something has finished,	555	Condition variables are very useful to signal that something has finished,
490	for example, if you write a module that does asynchronous http requests,	556	for example, if you write a module that does asynchronous http requests,
491	then a condition variable would be the ideal candidate to signal the	557	then a condition variable would be the ideal candidate to signal the
492	availability of results. The user can either act when the callback is	558	availability of results. The user can either act when the callback is
…		…
526	after => 1,	592	after => 1,
527	cb => sub { $result_ready->send },	593	cb => sub { $result_ready->send },
528	);	594	);
529		595
530	# this "blocks" (while handling events) till the callback	596	# this "blocks" (while handling events) till the callback
531	# calls send	597	# calls ->send
532	$result_ready->recv;	598	$result_ready->recv;
533		599
534	Example: wait for a timer, but take advantage of the fact that	600	Example: wait for a timer, but take advantage of the fact that condition
535	condition variables are also code references.	601	variables are also callable directly.
536		602
537	my $done = AnyEvent->condvar;	603	my $done = AnyEvent->condvar;
538	my $delay = AnyEvent->timer (after => 5, cb => $done);	604	my $delay = AnyEvent->timer (after => 5, cb => $done);
539	$done->recv;	605	$done->recv;
540		606
…		…
546		612
547	...	613	...
548		614
549	my @info = $couchdb->info->recv;	615	my @info = $couchdb->info->recv;
550		616
551	And this is how you would just ste a callback to be called whenever the	617	And this is how you would just set a callback to be called whenever the
552	results are available:	618	results are available:
553		619
554	$couchdb->info->cb (sub {	620	$couchdb->info->cb (sub {
555	my @info = $_[0]->recv;	621	my @info = $_[0]->recv;
556	});	622	});
…		…
574	immediately from within send.	640	immediately from within send.
575		641
576	Any arguments passed to the C<send> call will be returned by all	642	Any arguments passed to the C<send> call will be returned by all
577	future C<< ->recv >> calls.	643	future C<< ->recv >> calls.
578		644
579	Condition variables are overloaded so one can call them directly	645	Condition variables are overloaded so one can call them directly (as if
580	(as a code reference). Calling them directly is the same as calling	646	they were a code reference). Calling them directly is the same as calling
581	C<send>. Note, however, that many C-based event loops do not handle	647	C<send>.
582	overloading, so as tempting as it may be, passing a condition variable
583	instead of a callback does not work. Both the pure perl and EV loops
584	support overloading, however, as well as all functions that use perl to
585	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
586	example).
587		648
588	=item $cv->croak ($error)	649	=item $cv->croak ($error)
589		650
590	Similar to send, but causes all call's to C<< ->recv >> to invoke	651	Similar to send, but causes all call's to C<< ->recv >> to invoke
591	C<Carp::croak> with the given error message/object/scalar.	652	C<Carp::croak> with the given error message/object/scalar.
592		653
593	This can be used to signal any errors to the condition variable	654	This can be used to signal any errors to the condition variable
594	user/consumer.	655	user/consumer. Doing it this way instead of calling C<croak> directly
		656	delays the error detetcion, but has the overwhelmign advantage that it
		657	diagnoses the error at the place where the result is expected, and not
		658	deep in some event clalback without connection to the actual code causing
		659	the problem.
595		660
596	=item $cv->begin ([group callback])	661	=item $cv->begin ([group callback])
597		662
598	=item $cv->end	663	=item $cv->end
599
600	These two methods are EXPERIMENTAL and MIGHT CHANGE.
601		664
602	These two methods can be used to combine many transactions/events into	665	These two methods can be used to combine many transactions/events into
603	one. For example, a function that pings many hosts in parallel might want	666	one. For example, a function that pings many hosts in parallel might want
604	to use a condition variable for the whole process.	667	to use a condition variable for the whole process.
605		668
606	Every call to C<< ->begin >> will increment a counter, and every call to	669	Every call to C<< ->begin >> will increment a counter, and every call to
607	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	670	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
608	>>, the (last) callback passed to C<begin> will be executed. That callback	671	>>, the (last) callback passed to C<begin> will be executed, passing the
609	is I<supposed> to call C<< ->send >>, but that is not required. If no	672	condvar as first argument. That callback is I<supposed> to call C<< ->send
610	callback was set, C<send> will be called without any arguments.	673	>>, but that is not required. If no group callback was set, C<send> will
		674	be called without any arguments.
611		675
612	Let's clarify this with the ping example:	676	You can think of C<< $cv->send >> giving you an OR condition (one call
		677	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		678	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		679
		680	Let's start with a simple example: you have two I/O watchers (for example,
		681	STDOUT and STDERR for a program), and you want to wait for both streams to
		682	close before activating a condvar:
613		683
614	my $cv = AnyEvent->condvar;	684	my $cv = AnyEvent->condvar;
615		685
		686	$cv->begin; # first watcher
		687	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		688	defined sysread $fh1, my $buf, 4096
		689	or $cv->end;
		690	});
		691
		692	$cv->begin; # second watcher
		693	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		694	defined sysread $fh2, my $buf, 4096
		695	or $cv->end;
		696	});
		697
		698	$cv->recv;
		699
		700	This works because for every event source (EOF on file handle), there is
		701	one call to C<begin>, so the condvar waits for all calls to C<end> before
		702	sending.
		703
		704	The ping example mentioned above is slightly more complicated, as the
		705	there are results to be passwd back, and the number of tasks that are
		706	begung can potentially be zero:
		707
		708	my $cv = AnyEvent->condvar;
		709
616	my %result;	710	my %result;
617	$cv->begin (sub { $cv->send (\%result) });	711	$cv->begin (sub { shift->send (\%result) });
618		712
619	for my $host (@list_of_hosts) {	713	for my $host (@list_of_hosts) {
620	$cv->begin;	714	$cv->begin;
621	ping_host_then_call_callback $host, sub {	715	ping_host_then_call_callback $host, sub {
622	$result{$host} = ...;	716	$result{$host} = ...;
…		…
637	loop, which serves two important purposes: first, it sets the callback	731	loop, which serves two important purposes: first, it sets the callback
638	to be called once the counter reaches C<0>, and second, it ensures that	732	to be called once the counter reaches C<0>, and second, it ensures that
639	C<send> is called even when C<no> hosts are being pinged (the loop	733	C<send> is called even when C<no> hosts are being pinged (the loop
640	doesn't execute once).	734	doesn't execute once).
641		735
642	This is the general pattern when you "fan out" into multiple subrequests:	736	This is the general pattern when you "fan out" into multiple (but
643	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	737	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
644	is called at least once, and then, for each subrequest you start, call	738	the callback and ensure C<end> is called at least once, and then, for each
645	C<begin> and for each subrequest you finish, call C<end>.	739	subrequest you start, call C<begin> and for each subrequest you finish,
		740	call C<end>.
646		741
647	=back	742	=back
648		743
649	=head3 METHODS FOR CONSUMERS	744	=head3 METHODS FOR CONSUMERS
650		745
…		…
666	function will call C<croak>.	761	function will call C<croak>.
667		762
668	In list context, all parameters passed to C<send> will be returned,	763	In list context, all parameters passed to C<send> will be returned,
669	in scalar context only the first one will be returned.	764	in scalar context only the first one will be returned.
670		765
		766	Note that doing a blocking wait in a callback is not supported by any
		767	event loop, that is, recursive invocation of a blocking C<< ->recv
		768	>> is not allowed, and the C<recv> call will C<croak> if such a
		769	condition is detected. This condition can be slightly loosened by using
		770	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		771	any thread that doesn't run the event loop itself.
		772
671	Not all event models support a blocking wait - some die in that case	773	Not all event models support a blocking wait - some die in that case
672	(programs might want to do that to stay interactive), so I<if you are	774	(programs might want to do that to stay interactive), so I<if you are
673	using this from a module, never require a blocking wait>, but let the	775	using this from a module, never require a blocking wait>. Instead, let the
674	caller decide whether the call will block or not (for example, by coupling	776	caller decide whether the call will block or not (for example, by coupling
675	condition variables with some kind of request results and supporting	777	condition variables with some kind of request results and supporting
676	callbacks so the caller knows that getting the result will not block,	778	callbacks so the caller knows that getting the result will not block,
677	while still supporting blocking waits if the caller so desires).	779	while still supporting blocking waits if the caller so desires).
678		780
679	Another reason I<never> to C<< ->recv >> in a module is that you cannot
680	sensibly have two C<< ->recv >>'s in parallel, as that would require
681	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
682	can supply.
683
684	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
685	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
686	versions and also integrates coroutines into AnyEvent, making blocking
687	C<< ->recv >> calls perfectly safe as long as they are done from another
688	coroutine (one that doesn't run the event loop).
689
690	You can ensure that C<< -recv >> never blocks by setting a callback and	781	You can ensure that C<< -recv >> never blocks by setting a callback and
691	only calling C<< ->recv >> from within that callback (or at a later	782	only calling C<< ->recv >> from within that callback (or at a later
692	time). This will work even when the event loop does not support blocking	783	time). This will work even when the event loop does not support blocking
693	waits otherwise.	784	waits otherwise.
694		785
…		…
700	=item $cb = $cv->cb ($cb->($cv))	791	=item $cb = $cv->cb ($cb->($cv))
701		792
702	This is a mutator function that returns the callback set and optionally	793	This is a mutator function that returns the callback set and optionally
703	replaces it before doing so.	794	replaces it before doing so.
704		795
705	The callback will be called when the condition becomes "true", i.e. when	796	The callback will be called when the condition becomes (or already was)
706	C<send> or C<croak> are called, with the only argument being the condition	797	"true", i.e. when C<send> or C<croak> are called (or were called), with
707	variable itself. Calling C<recv> inside the callback or at any later time	798	the only argument being the condition variable itself. Calling C<recv>
708	is guaranteed not to block.	799	inside the callback or at any later time is guaranteed not to block.
709		800
710	=back	801	=back
711		802
		803	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		804
		805	The available backend classes are (every class has its own manpage):
		806
		807	=over 4
		808
		809	=item Backends that are autoprobed when no other event loop can be found.
		810
		811	EV is the preferred backend when no other event loop seems to be in
		812	use. If EV is not installed, then AnyEvent will fall back to its own
		813	pure-perl implementation, which is available everywhere as it comes with
		814	AnyEvent itself.
		815
		816	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		817	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		818
		819	=item Backends that are transparently being picked up when they are used.
		820
		821	These will be used when they are currently loaded when the first watcher
		822	is created, in which case it is assumed that the application is using
		823	them. This means that AnyEvent will automatically pick the right backend
		824	when the main program loads an event module before anything starts to
		825	create watchers. Nothing special needs to be done by the main program.
		826
		827	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		828	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		829	AnyEvent::Impl::Tk based on Tk, very broken.
		830	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		831	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		832	AnyEvent::Impl::Irssi used when running within irssi.
		833
		834	=item Backends with special needs.
		835
		836	Qt requires the Qt::Application to be instantiated first, but will
		837	otherwise be picked up automatically. As long as the main program
		838	instantiates the application before any AnyEvent watchers are created,
		839	everything should just work.
		840
		841	AnyEvent::Impl::Qt based on Qt.
		842
		843	Support for IO::Async can only be partial, as it is too broken and
		844	architecturally limited to even support the AnyEvent API. It also
		845	is the only event loop that needs the loop to be set explicitly, so
		846	it can only be used by a main program knowing about AnyEvent. See
		847	L<AnyEvent::Impl::Async> for the gory details.
		848
		849	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		850
		851	=item Event loops that are indirectly supported via other backends.
		852
		853	Some event loops can be supported via other modules:
		854
		855	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		856
		857	B<WxWidgets> has no support for watching file handles. However, you can
		858	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		859	polls 20 times per second, which was considered to be too horrible to even
		860	consider for AnyEvent.
		861
		862	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		863	backend, so it can be supported through POE.
		864
		865	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		866	load L<POE> when detecting them, in the hope that POE will pick them up,
		867	in which case everything will be automatic.
		868
		869	=back
		870
712	=head1 GLOBAL VARIABLES AND FUNCTIONS	871	=head1 GLOBAL VARIABLES AND FUNCTIONS
713		872
		873	These are not normally required to use AnyEvent, but can be useful to
		874	write AnyEvent extension modules.
		875
714	=over 4	876	=over 4
715		877
716	=item $AnyEvent::MODEL	878	=item $AnyEvent::MODEL
717		879
718	Contains C<undef> until the first watcher is being created. Then it	880	Contains C<undef> until the first watcher is being created, before the
		881	backend has been autodetected.
		882
719	contains the event model that is being used, which is the name of the	883	Afterwards it contains the event model that is being used, which is the
720	Perl class implementing the model. This class is usually one of the	884	name of the Perl class implementing the model. This class is usually one
721	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	885	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
722	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	886	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
723		887	will be C<urxvt::anyevent>).
724	The known classes so far are:
725
726	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
727	AnyEvent::Impl::Event based on Event, second best choice.
728	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
729	AnyEvent::Impl::Glib based on Glib, third-best choice.
730	AnyEvent::Impl::Tk based on Tk, very bad choice.
731	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
732	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
733	AnyEvent::Impl::POE based on POE, not generic enough for full support.
734
735	There is no support for WxWidgets, as WxWidgets has no support for
736	watching file handles. However, you can use WxWidgets through the
737	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
738	second, which was considered to be too horrible to even consider for
739	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
740	it's adaptor.
741
742	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
743	autodetecting them.
744		888
745	=item AnyEvent::detect	889	=item AnyEvent::detect
746		890
747	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	891	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
748	if necessary. You should only call this function right before you would	892	if necessary. You should only call this function right before you would
749	have created an AnyEvent watcher anyway, that is, as late as possible at	893	have created an AnyEvent watcher anyway, that is, as late as possible at
750	runtime.	894	runtime, and not e.g. while initialising of your module.
		895
		896	If you need to do some initialisation before AnyEvent watchers are
		897	created, use C<post_detect>.
751		898
752	=item $guard = AnyEvent::post_detect { BLOCK }	899	=item $guard = AnyEvent::post_detect { BLOCK }
753		900
754	Arranges for the code block to be executed as soon as the event model is	901	Arranges for the code block to be executed as soon as the event model is
755	autodetected (or immediately if this has already happened).	902	autodetected (or immediately if this has already happened).
756		903
		904	The block will be executed I<after> the actual backend has been detected
		905	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		906	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		907	other initialisations - see the sources of L<AnyEvent::Strict> or
		908	L<AnyEvent::AIO> to see how this is used.
		909
		910	The most common usage is to create some global watchers, without forcing
		911	event module detection too early, for example, L<AnyEvent::AIO> creates
		912	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		913	avoid autodetecting the event module at load time.
		914
757	If called in scalar or list context, then it creates and returns an object	915	If called in scalar or list context, then it creates and returns an object
758	that automatically removes the callback again when it is destroyed. See	916	that automatically removes the callback again when it is destroyed (or
		917	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
759	L<Coro::BDB> for a case where this is useful.	918	a case where this is useful.
		919
		920	Example: Create a watcher for the IO::AIO module and store it in
		921	C<$WATCHER>. Only do so after the event loop is initialised, though.
		922
		923	our WATCHER;
		924
		925	my $guard = AnyEvent::post_detect {
		926	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		927	};
		928
		929	# the ||= is important in case post_detect immediately runs the block,
		930	# as to not clobber the newly-created watcher. assigning both watcher and
		931	# post_detect guard to the same variable has the advantage of users being
		932	# able to just C<undef $WATCHER> if the watcher causes them grief.
		933
		934	$WATCHER ||= $guard;
760		935
761	=item @AnyEvent::post_detect	936	=item @AnyEvent::post_detect
762		937
763	If there are any code references in this array (you can C<push> to it	938	If there are any code references in this array (you can C<push> to it
764	before or after loading AnyEvent), then they will called directly after	939	before or after loading AnyEvent), then they will called directly after
765	the event loop has been chosen.	940	the event loop has been chosen.
766		941
767	You should check C<$AnyEvent::MODEL> before adding to this array, though:	942	You should check C<$AnyEvent::MODEL> before adding to this array, though:
768	if it contains a true value then the event loop has already been detected,	943	if it is defined then the event loop has already been detected, and the
769	and the array will be ignored.	944	array will be ignored.
770		945
771	Best use C<AnyEvent::post_detect { BLOCK }> instead.	946	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		947	it,as it takes care of these details.
		948
		949	This variable is mainly useful for modules that can do something useful
		950	when AnyEvent is used and thus want to know when it is initialised, but do
		951	not need to even load it by default. This array provides the means to hook
		952	into AnyEvent passively, without loading it.
772		953
773	=back	954	=back
774		955
775	=head1 WHAT TO DO IN A MODULE	956	=head1 WHAT TO DO IN A MODULE
776		957
…		…
831		1012
832		1013
833	=head1 OTHER MODULES	1014	=head1 OTHER MODULES
834		1015
835	The following is a non-exhaustive list of additional modules that use	1016	The following is a non-exhaustive list of additional modules that use
836	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1017	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
837	in the same program. Some of the modules come with AnyEvent, some are	1018	modules and other event loops in the same program. Some of the modules
838	available via CPAN.	1019	come with AnyEvent, most are available via CPAN.
839		1020
840	=over 4	1021	=over 4
841		1022
842	=item L<AnyEvent::Util>	1023	=item L<AnyEvent::Util>
843		1024
…		…
852		1033
853	=item L<AnyEvent::Handle>	1034	=item L<AnyEvent::Handle>
854		1035
855	Provide read and write buffers, manages watchers for reads and writes,	1036	Provide read and write buffers, manages watchers for reads and writes,
856	supports raw and formatted I/O, I/O queued and fully transparent and	1037	supports raw and formatted I/O, I/O queued and fully transparent and
857	non-blocking SSL/TLS.	1038	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
858		1039
859	=item L<AnyEvent::DNS>	1040	=item L<AnyEvent::DNS>
860		1041
861	Provides rich asynchronous DNS resolver capabilities.	1042	Provides rich asynchronous DNS resolver capabilities.
862		1043
…		…
890		1071
891	=item L<AnyEvent::GPSD>	1072	=item L<AnyEvent::GPSD>
892		1073
893	A non-blocking interface to gpsd, a daemon delivering GPS information.	1074	A non-blocking interface to gpsd, a daemon delivering GPS information.
894		1075
		1076	=item L<AnyEvent::IRC>
		1077
		1078	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1079
		1080	=item L<AnyEvent::XMPP>
		1081
		1082	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1083	Net::XMPP2>.
		1084
895	=item L<AnyEvent::IGS>	1085	=item L<AnyEvent::IGS>
896		1086
897	A non-blocking interface to the Internet Go Server protocol (used by	1087	A non-blocking interface to the Internet Go Server protocol (used by
898	L<App::IGS>).	1088	L<App::IGS>).
899		1089
900	=item L<AnyEvent::IRC>
901
902	AnyEvent based IRC client module family (replacing the older Net::IRC3).
903
904	=item L<Net::XMPP2>
905
906	AnyEvent based XMPP (Jabber protocol) module family.
907
908	=item L<Net::FCP>	1090	=item L<Net::FCP>
909		1091
910	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1092	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
911	of AnyEvent.	1093	of AnyEvent.
912		1094
…		…
916		1098
917	=item L<Coro>	1099	=item L<Coro>
918		1100
919	Has special support for AnyEvent via L<Coro::AnyEvent>.	1101	Has special support for AnyEvent via L<Coro::AnyEvent>.
920		1102
921	=item L<IO::Lambda>
922
923	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
924
925	=back	1103	=back
926		1104
927	=cut	1105	=cut
928		1106
929	package AnyEvent;	1107	package AnyEvent;
930		1108
		1109	# basically a tuned-down version of common::sense
		1110	sub common_sense {
931	no warnings;	1111	# no warnings
		1112	${^WARNING_BITS} ^= ${^WARNING_BITS};
932	use strict qw(vars subs);	1113	# use strict vars subs
		1114	$^H |= 0x00000600;
		1115	}
933		1116
		1117	BEGIN { AnyEvent::common_sense }
		1118
934	use Carp;	1119	use Carp ();
935		1120
936	our $VERSION = 4.411;	1121	our $VERSION = '5.112';
937	our $MODEL;	1122	our $MODEL;
938		1123
939	our $AUTOLOAD;	1124	our $AUTOLOAD;
940	our @ISA;	1125	our @ISA;
941		1126
942	our @REGISTRY;	1127	our @REGISTRY;
943		1128
944	our $WIN32;	1129	our $WIN32;
945		1130
		1131	our $VERBOSE;
		1132
946	BEGIN {	1133	BEGIN {
947	my $win32 = ! ! ($^O =~ /mswin32/i);	1134	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
948	eval "sub WIN32(){ $win32 }";	1135	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
949	}
950		1136
		1137	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1138	if ${^TAINT};
		1139
951	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1140	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1141
		1142	}
		1143
		1144	our $MAX_SIGNAL_LATENCY = 10;
952		1145
953	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1146	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
954		1147
955	{	1148	{
956	my $idx;	1149	my $idx;
…		…
958	for reverse split /\s*,\s*/,	1151	for reverse split /\s*,\s*/,
959	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1152	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
960	}	1153	}
961		1154
962	my @models = (	1155	my @models = (
963	[EV:: => AnyEvent::Impl::EV::],	1156	[EV:: => AnyEvent::Impl::EV:: , 1],
964	[Event:: => AnyEvent::Impl::Event::],
965	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1157	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
966	# everything below here will not be autoprobed	1158	# everything below here will not (normally) be autoprobed
967	# as the pureperl backend should work everywhere	1159	# as the pureperl backend should work everywhere
968	# and is usually faster	1160	# and is usually faster
		1161	[Event:: => AnyEvent::Impl::Event::, 1],
		1162	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1163	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1164	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
969	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1165	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
970	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
971	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
972	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1166	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
973	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1167	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
974	[Wx:: => AnyEvent::Impl::POE::],	1168	[Wx:: => AnyEvent::Impl::POE::],
975	[Prima:: => AnyEvent::Impl::POE::],	1169	[Prima:: => AnyEvent::Impl::POE::],
		1170	# IO::Async is just too broken - we would need workarounds for its
		1171	# byzantine signal and broken child handling, among others.
		1172	# IO::Async is rather hard to detect, as it doesn't have any
		1173	# obvious default class.
		1174	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1175	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1176	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1177	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
976	);	1178	);
977		1179
978	our %method = map +($_ => 1),	1180	our %method = map +($_ => 1),
979	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1181	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
980		1182
…		…
984	my ($cb) = @_;	1186	my ($cb) = @_;
985		1187
986	if ($MODEL) {	1188	if ($MODEL) {
987	$cb->();	1189	$cb->();
988		1190
989	1	1191	undef
990	} else {	1192	} else {
991	push @post_detect, $cb;	1193	push @post_detect, $cb;
992		1194
993	defined wantarray	1195	defined wantarray
994	? bless \$cb, "AnyEvent::Util::postdetect"	1196	? bless \$cb, "AnyEvent::Util::postdetect"
…		…
1000	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1202	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1001	}	1203	}
1002		1204
1003	sub detect() {	1205	sub detect() {
1004	unless ($MODEL) {	1206	unless ($MODEL) {
1005	no strict 'refs';
1006	local $SIG{__DIE__};	1207	local $SIG{__DIE__};
1007		1208
1008	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1209	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1009	my $model = "AnyEvent::Impl::$1";	1210	my $model = "AnyEvent::Impl::$1";
1010	if (eval "require $model") {	1211	if (eval "require $model") {
1011	$MODEL = $model;	1212	$MODEL = $model;
1012	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1213	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1013	} else {	1214	} else {
1014	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1215	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1015	}	1216	}
1016	}	1217	}
1017		1218
1018	# check for already loaded models	1219	# check for already loaded models
1019	unless ($MODEL) {	1220	unless ($MODEL) {
1020	for (@REGISTRY, @models) {	1221	for (@REGISTRY, @models) {
1021	my ($package, $model) = @$_;	1222	my ($package, $model) = @$_;
1022	if (${"$package\::VERSION"} > 0) {	1223	if (${"$package\::VERSION"} > 0) {
1023	if (eval "require $model") {	1224	if (eval "require $model") {
1024	$MODEL = $model;	1225	$MODEL = $model;
1025	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1226	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1026	last;	1227	last;
1027	}	1228	}
1028	}	1229	}
1029	}	1230	}
1030		1231
1031	unless ($MODEL) {	1232	unless ($MODEL) {
1032	# try to load a model	1233	# try to autoload a model
1033
1034	for (@REGISTRY, @models) {	1234	for (@REGISTRY, @models) {
1035	my ($package, $model) = @$_;	1235	my ($package, $model, $autoload) = @$_;
		1236	if (
		1237	$autoload
1036	if (eval "require $package"	1238	and eval "require $package"
1037	and ${"$package\::VERSION"} > 0	1239	and ${"$package\::VERSION"} > 0
1038	and eval "require $model") {	1240	and eval "require $model"
		1241	) {
1039	$MODEL = $model;	1242	$MODEL = $model;
1040	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1243	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1041	last;	1244	last;
1042	}	1245	}
1043	}	1246	}
1044		1247
1045	$MODEL	1248	$MODEL
…		…
1061		1264
1062	sub AUTOLOAD {	1265	sub AUTOLOAD {
1063	(my $func = $AUTOLOAD) =~ s/.*://;	1266	(my $func = $AUTOLOAD) =~ s/.*://;
1064		1267
1065	$method{$func}	1268	$method{$func}
1066	or croak "$func: not a valid method for AnyEvent objects";	1269	or Carp::croak "$func: not a valid method for AnyEvent objects";
1067		1270
1068	detect unless $MODEL;	1271	detect unless $MODEL;
1069		1272
1070	my $class = shift;	1273	my $class = shift;
1071	$class->$func (@_);	1274	$class->$func (@_);
1072	}	1275	}
1073		1276
1074	# utility function to dup a filehandle. this is used by many backends	1277	# utility function to dup a filehandle. this is used by many backends
1075	# to support binding more than one watcher per filehandle (they usually	1278	# to support binding more than one watcher per filehandle (they usually
1076	# allow only one watcher per fd, so we dup it to get a different one).	1279	# allow only one watcher per fd, so we dup it to get a different one).
1077	sub _dupfh($$$$) {	1280	sub _dupfh($$;$$) {
1078	my ($poll, $fh, $r, $w) = @_;	1281	my ($poll, $fh, $r, $w) = @_;
1079		1282
1080	# cygwin requires the fh mode to be matching, unix doesn't	1283	# cygwin requires the fh mode to be matching, unix doesn't
1081	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1284	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1082	: $poll eq "w" ? ($w, ">")
1083	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1084		1285
1085	open my $fh2, "$mode&" . fileno $fh	1286	open my $fh2, $mode, $fh
1086	or die "cannot dup() filehandle: $!,";	1287	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1087		1288
1088	# we assume CLOEXEC is already set by perl in all important cases	1289	# we assume CLOEXEC is already set by perl in all important cases
1089		1290
1090	($fh2, $rw)	1291	($fh2, $rw)
1091	}	1292	}
1092		1293
		1294	=head1 SIMPLIFIED AE API
		1295
		1296	Starting with version 5.0, AnyEvent officially supports a second, much
		1297	simpler, API that is designed to reduce the calling, typing and memory
		1298	overhead.
		1299
		1300	See the L<AE> manpage for details.
		1301
		1302	=cut
		1303
		1304	package AE;
		1305
		1306	our $VERSION = $AnyEvent::VERSION;
		1307
		1308	sub io($$$) {
		1309	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1310	}
		1311
		1312	sub timer($$$) {
		1313	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1314	}
		1315
		1316	sub signal($$) {
		1317	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1318	}
		1319
		1320	sub child($$) {
		1321	AnyEvent->child (pid => $_[0], cb => $_[1])
		1322	}
		1323
		1324	sub idle($) {
		1325	AnyEvent->idle (cb => $_[0])
		1326	}
		1327
		1328	sub cv(;&) {
		1329	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1330	}
		1331
		1332	sub now() {
		1333	AnyEvent->now
		1334	}
		1335
		1336	sub now_update() {
		1337	AnyEvent->now_update
		1338	}
		1339
		1340	sub time() {
		1341	AnyEvent->time
		1342	}
		1343
1093	package AnyEvent::Base;	1344	package AnyEvent::Base;
1094		1345
1095	# default implementations for many methods	1346	# default implementations for many methods
1096		1347
1097	BEGIN {	1348	sub _time {
		1349	# probe for availability of Time::HiRes
1098	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1350	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1351	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1099	*_time = \&Time::HiRes::time;	1352	*_time = \&Time::HiRes::time;
1100	# if (eval "use POSIX (); (POSIX::times())...	1353	# if (eval "use POSIX (); (POSIX::times())...
1101	} else {	1354	} else {
		1355	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1102	*_time = sub { time }; # epic fail	1356	*_time = sub { time }; # epic fail
1103	}	1357	}
		1358
		1359	&_time
1104	}	1360	}
1105		1361
1106	sub time { _time }	1362	sub time { _time }
1107	sub now { _time }	1363	sub now { _time }
1108	sub now_update { }	1364	sub now_update { }
…		…
1113	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1369	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1114	}	1370	}
1115		1371
1116	# default implementation for ->signal	1372	# default implementation for ->signal
1117		1373
		1374	our $HAVE_ASYNC_INTERRUPT;
		1375
		1376	sub _have_async_interrupt() {
		1377	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1378	&& eval "use Async::Interrupt 1.0 (); 1")
		1379	unless defined $HAVE_ASYNC_INTERRUPT;
		1380
		1381	$HAVE_ASYNC_INTERRUPT
		1382	}
		1383
1118	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1384	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1385	our (%SIG_ASY, %SIG_ASY_W);
		1386	our ($SIG_COUNT, $SIG_TW);
1119		1387
1120	sub _signal_exec {	1388	sub _signal_exec {
		1389	$HAVE_ASYNC_INTERRUPT
		1390	? $SIGPIPE_R->drain
1121	sysread $SIGPIPE_R, my $dummy, 4;	1391	: sysread $SIGPIPE_R, my $dummy, 9;
1122		1392
1123	while (%SIG_EV) {	1393	while (%SIG_EV) {
1124	for (keys %SIG_EV) {	1394	for (keys %SIG_EV) {
1125	delete $SIG_EV{$_};	1395	delete $SIG_EV{$_};
1126	$_->() for values %{ $SIG_CB{$_} || {} };	1396	$_->() for values %{ $SIG_CB{$_} || {} };
1127	}	1397	}
1128	}	1398	}
1129	}	1399	}
1130		1400
		1401	# install a dummy wakeup watcher to reduce signal catching latency
		1402	sub _sig_add() {
		1403	unless ($SIG_COUNT++) {
		1404	# try to align timer on a full-second boundary, if possible
		1405	my $NOW = AE::now;
		1406
		1407	$SIG_TW = AE::timer
		1408	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1409	$MAX_SIGNAL_LATENCY,
		1410	sub { } # just for the PERL_ASYNC_CHECK
		1411	;
		1412	}
		1413	}
		1414
		1415	sub _sig_del {
		1416	undef $SIG_TW
		1417	unless --$SIG_COUNT;
		1418	}
		1419
		1420	our $_sig_name_init; $_sig_name_init = sub {
		1421	eval q{ # poor man's autoloading
		1422	undef $_sig_name_init;
		1423
		1424	if (_have_async_interrupt) {
		1425	*sig2num = \&Async::Interrupt::sig2num;
		1426	*sig2name = \&Async::Interrupt::sig2name;
		1427	} else {
		1428	require Config;
		1429
		1430	my %signame2num;
		1431	@signame2num{ split ' ', $Config::Config{sig_name} }
		1432	= split ' ', $Config::Config{sig_num};
		1433
		1434	my @signum2name;
		1435	@signum2name[values %signame2num] = keys %signame2num;
		1436
		1437	*sig2num = sub($) {
		1438	$_[0] > 0 ? shift : $signame2num{+shift}
		1439	};
		1440	*sig2name = sub ($) {
		1441	$_[0] > 0 ? $signum2name[+shift] : shift
		1442	};
		1443	}
		1444	};
		1445	die if $@;
		1446	};
		1447
		1448	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1449	sub sig2name($) { &$_sig_name_init; &sig2name }
		1450
1131	sub signal {	1451	sub signal {
1132	my (undef, %arg) = @_;	1452	eval q{ # poor man's autoloading {}
		1453	# probe for availability of Async::Interrupt
		1454	if (_have_async_interrupt) {
		1455	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1133		1456
1134	unless ($SIGPIPE_R) {	1457	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1135	require Fcntl;	1458	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1136		1459
1137	if (AnyEvent::WIN32) {
1138	require AnyEvent::Util;
1139
1140	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1141	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1142	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1143	} else {	1460	} else {
		1461	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1462
		1463	require Fcntl;
		1464
		1465	if (AnyEvent::WIN32) {
		1466	require AnyEvent::Util;
		1467
		1468	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1469	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1470	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1471	} else {
1144	pipe $SIGPIPE_R, $SIGPIPE_W;	1472	pipe $SIGPIPE_R, $SIGPIPE_W;
1145	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1473	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1146	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1474	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1147		1475
1148	# not strictly required, as $^F is normally 2, but let's make sure...	1476	# not strictly required, as $^F is normally 2, but let's make sure...
1149	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1477	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1150	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1478	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1479	}
		1480
		1481	$SIGPIPE_R
		1482	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1483
		1484	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1151	}	1485	}
1152		1486
1153	$SIGPIPE_R	1487	*signal = sub {
1154	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1488	my (undef, %arg) = @_;
1155		1489
1156	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1157	}
1158
1159	my $signal = uc $arg{signal}	1490	my $signal = uc $arg{signal}
1160	or Carp::croak "required option 'signal' is missing";	1491	or Carp::croak "required option 'signal' is missing";
1161		1492
		1493	if ($HAVE_ASYNC_INTERRUPT) {
		1494	# async::interrupt
		1495
		1496	$signal = sig2num $signal;
1162	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1497	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1498
		1499	$SIG_ASY{$signal} ||= new Async::Interrupt
		1500	cb => sub { undef $SIG_EV{$signal} },
		1501	signal => $signal,
		1502	pipe => [$SIGPIPE_R->filenos],
		1503	pipe_autodrain => 0,
		1504	;
		1505
		1506	} else {
		1507	# pure perl
		1508
		1509	# AE::Util has been loaded in signal
		1510	$signal = sig2name $signal;
		1511	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1512
1163	$SIG{$signal} ||= sub {	1513	$SIG{$signal} ||= sub {
1164	local $!;	1514	local $!;
1165	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1515	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1166	undef $SIG_EV{$signal};	1516	undef $SIG_EV{$signal};
		1517	};
		1518
		1519	# can't do signal processing without introducing races in pure perl,
		1520	# so limit the signal latency.
		1521	_sig_add;
		1522	}
		1523
		1524	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1525	};
		1526
		1527	*AnyEvent::Base::signal::DESTROY = sub {
		1528	my ($signal, $cb) = @{$_[0]};
		1529
		1530	_sig_del;
		1531
		1532	delete $SIG_CB{$signal}{$cb};
		1533
		1534	$HAVE_ASYNC_INTERRUPT
		1535	? delete $SIG_ASY{$signal}
		1536	: # delete doesn't work with older perls - they then
		1537	# print weird messages, or just unconditionally exit
		1538	# instead of getting the default action.
		1539	undef $SIG{$signal}
		1540	unless keys %{ $SIG_CB{$signal} };
		1541	};
1167	};	1542	};
1168		1543	die if $@;
1169	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1544	&signal
1170	}
1171
1172	sub AnyEvent::Base::signal::DESTROY {
1173	my ($signal, $cb) = @{$_[0]};
1174
1175	delete $SIG_CB{$signal}{$cb};
1176
1177	# delete doesn't work with older perls - they then
1178	# print weird messages, or just unconditionally exit
1179	# instead of getting the default action.
1180	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1181	}	1545	}
1182		1546
1183	# default implementation for ->child	1547	# default implementation for ->child
1184		1548
1185	our %PID_CB;	1549	our %PID_CB;
1186	our $CHLD_W;	1550	our $CHLD_W;
1187	our $CHLD_DELAY_W;	1551	our $CHLD_DELAY_W;
1188	our $WNOHANG;	1552	our $WNOHANG;
1189		1553
		1554	sub _emit_childstatus($$) {
		1555	my (undef, $rpid, $rstatus) = @_;
		1556
		1557	$_->($rpid, $rstatus)
		1558	for values %{ $PID_CB{$rpid} || {} },
		1559	values %{ $PID_CB{0} || {} };
		1560	}
		1561
1190	sub _sigchld {	1562	sub _sigchld {
		1563	my $pid;
		1564
		1565	AnyEvent->_emit_childstatus ($pid, $?)
1191	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1566	while ($pid = waitpid -1, $WNOHANG) > 0;
1192	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),
1193	(values %{ $PID_CB{0} || {} });
1194	}
1195	}	1567	}
1196		1568
1197	sub child {	1569	sub child {
1198	my (undef, %arg) = @_;	1570	my (undef, %arg) = @_;
1199		1571
1200	defined (my $pid = $arg{pid} + 0)	1572	defined (my $pid = $arg{pid} + 0)
1201	or Carp::croak "required option 'pid' is missing";	1573	or Carp::croak "required option 'pid' is missing";
1202		1574
1203	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1575	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1204		1576
		1577	# WNOHANG is almost cetrainly 1 everywhere
		1578	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1579	? 1
1205	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1580	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1206		1581
1207	unless ($CHLD_W) {	1582	unless ($CHLD_W) {
1208	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1583	$CHLD_W = AE::signal CHLD => \&_sigchld;
1209	# child could be a zombie already, so make at least one round	1584	# child could be a zombie already, so make at least one round
1210	&_sigchld;	1585	&_sigchld;
1211	}	1586	}
1212		1587
1213	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1588	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
…		…
1239	# never use more then 50% of the time for the idle watcher,	1614	# never use more then 50% of the time for the idle watcher,
1240	# within some limits	1615	# within some limits
1241	$w = 0.0001 if $w < 0.0001;	1616	$w = 0.0001 if $w < 0.0001;
1242	$w = 5 if $w > 5;	1617	$w = 5 if $w > 5;
1243		1618
1244	$w = AnyEvent->timer (after => $w, cb => $rcb);	1619	$w = AE::timer $w, 0, $rcb;
1245	} else {	1620	} else {
1246	# clean up...	1621	# clean up...
1247	undef $w;	1622	undef $w;
1248	undef $rcb;	1623	undef $rcb;
1249	}	1624	}
1250	};	1625	};
1251		1626
1252	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1627	$w = AE::timer 0.05, 0, $rcb;
1253		1628
1254	bless \\$cb, "AnyEvent::Base::idle"	1629	bless \\$cb, "AnyEvent::Base::idle"
1255	}	1630	}
1256		1631
1257	sub AnyEvent::Base::idle::DESTROY {	1632	sub AnyEvent::Base::idle::DESTROY {
…		…
1262		1637
1263	our @ISA = AnyEvent::CondVar::Base::;	1638	our @ISA = AnyEvent::CondVar::Base::;
1264		1639
1265	package AnyEvent::CondVar::Base;	1640	package AnyEvent::CondVar::Base;
1266		1641
1267	use overload	1642	#use overload
1268	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1643	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1269	fallback => 1;	1644	# fallback => 1;
		1645
		1646	# save 300+ kilobytes by dirtily hardcoding overloading
		1647	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1648	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1649	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1650	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1651
		1652	our $WAITING;
1270		1653
1271	sub _send {	1654	sub _send {
1272	# nop	1655	# nop
1273	}	1656	}
1274		1657
…		…
1287	sub ready {	1670	sub ready {
1288	$_[0]{_ae_sent}	1671	$_[0]{_ae_sent}
1289	}	1672	}
1290		1673
1291	sub _wait {	1674	sub _wait {
		1675	$WAITING
		1676	and !$_[0]{_ae_sent}
		1677	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1678
		1679	local $WAITING = 1;
1292	AnyEvent->one_event while !$_[0]{_ae_sent};	1680	AnyEvent->one_event while !$_[0]{_ae_sent};
1293	}	1681	}
1294		1682
1295	sub recv {	1683	sub recv {
1296	$_[0]->_wait;	1684	$_[0]->_wait;
…		…
1298	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1686	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1299	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1687	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1300	}	1688	}
1301		1689
1302	sub cb {	1690	sub cb {
1303	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1691	my $cv = shift;
		1692
		1693	@_
		1694	and $cv->{_ae_cb} = shift
		1695	and $cv->{_ae_sent}
		1696	and (delete $cv->{_ae_cb})->($cv);
		1697
1304	$_[0]{_ae_cb}	1698	$cv->{_ae_cb}
1305	}	1699	}
1306		1700
1307	sub begin {	1701	sub begin {
1308	++$_[0]{_ae_counter};	1702	++$_[0]{_ae_counter};
1309	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1703	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1337	so on.	1731	so on.
1338		1732
1339	=head1 ENVIRONMENT VARIABLES	1733	=head1 ENVIRONMENT VARIABLES
1340		1734
1341	The following environment variables are used by this module or its	1735	The following environment variables are used by this module or its
1342	submodules:	1736	submodules.
		1737
		1738	Note that AnyEvent will remove I<all> environment variables starting with
		1739	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1740	enabled.
1343		1741
1344	=over 4	1742	=over 4
1345		1743
1346	=item C<PERL_ANYEVENT_VERBOSE>	1744	=item C<PERL_ANYEVENT_VERBOSE>
1347		1745
…		…
1354	C<PERL_ANYEVENT_MODEL>.	1752	C<PERL_ANYEVENT_MODEL>.
1355		1753
1356	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1754	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1357	model it chooses.	1755	model it chooses.
1358		1756
		1757	When set to C<8> or higher, then AnyEvent will report extra information on
		1758	which optional modules it loads and how it implements certain features.
		1759
1359	=item C<PERL_ANYEVENT_STRICT>	1760	=item C<PERL_ANYEVENT_STRICT>
1360		1761
1361	AnyEvent does not do much argument checking by default, as thorough	1762	AnyEvent does not do much argument checking by default, as thorough
1362	argument checking is very costly. Setting this variable to a true value	1763	argument checking is very costly. Setting this variable to a true value
1363	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1764	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1364	check the arguments passed to most method calls. If it finds any problems	1765	check the arguments passed to most method calls. If it finds any problems,
1365	it will croak.	1766	it will croak.
1366		1767
1367	In other words, enables "strict" mode.	1768	In other words, enables "strict" mode.
1368		1769
1369	Unlike C<use strict>, it is definitely recommended ot keep it off in	1770	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1370	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1771	>>, it is definitely recommended to keep it off in production. Keeping
1371	developing programs can be very useful, however.	1772	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1773	can be very useful, however.
1372		1774
1373	=item C<PERL_ANYEVENT_MODEL>	1775	=item C<PERL_ANYEVENT_MODEL>
1374		1776
1375	This can be used to specify the event model to be used by AnyEvent, before	1777	This can be used to specify the event model to be used by AnyEvent, before
1376	auto detection and -probing kicks in. It must be a string consisting	1778	auto detection and -probing kicks in. It must be a string consisting
…		…
1419		1821
1420	=item C<PERL_ANYEVENT_MAX_FORKS>	1822	=item C<PERL_ANYEVENT_MAX_FORKS>
1421		1823
1422	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1824	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1423	will create in parallel.	1825	will create in parallel.
		1826
		1827	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1828
		1829	The default value for the C<max_outstanding> parameter for the default DNS
		1830	resolver - this is the maximum number of parallel DNS requests that are
		1831	sent to the DNS server.
		1832
		1833	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1834
		1835	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1836	configuration) in the default resolver. When set to the empty string, no
		1837	default config will be used.
		1838
		1839	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1840
		1841	When neither C<ca_file> nor C<ca_path> was specified during
		1842	L<AnyEvent::TLS> context creation, and either of these environment
		1843	variables exist, they will be used to specify CA certificate locations
		1844	instead of a system-dependent default.
		1845
		1846	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1847
		1848	When these are set to C<1>, then the respective modules are not
		1849	loaded. Mostly good for testing AnyEvent itself.
1424		1850
1425	=back	1851	=back
1426		1852
1427	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1853	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1428		1854
…		…
1486	warn "read: $input\n"; # output what has been read	1912	warn "read: $input\n"; # output what has been read
1487	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1913	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1488	},	1914	},
1489	);	1915	);
1490		1916
1491	my $time_watcher; # can only be used once
1492
1493	sub new_timer {
1494	$timer = AnyEvent->timer (after => 1, cb => sub {	1917	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1495	warn "timeout\n"; # print 'timeout' about every second	1918	warn "timeout\n"; # print 'timeout' at most every second
1496	&new_timer; # and restart the time
1497	});	1919	});
1498	}
1499
1500	new_timer; # create first timer
1501		1920
1502	$cv->recv; # wait until user enters /^q/i	1921	$cv->recv; # wait until user enters /^q/i
1503		1922
1504	=head1 REAL-WORLD EXAMPLE	1923	=head1 REAL-WORLD EXAMPLE
1505		1924
…		…
1636	through AnyEvent. The benchmark creates a lot of timers (with a zero	2055	through AnyEvent. The benchmark creates a lot of timers (with a zero
1637	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2056	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1638	which it is), lets them fire exactly once and destroys them again.	2057	which it is), lets them fire exactly once and destroys them again.
1639		2058
1640	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2059	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1641	distribution.	2060	distribution. It uses the L<AE> interface, which makes a real difference
		2061	for the EV and Perl backends only.
1642		2062
1643	=head3 Explanation of the columns	2063	=head3 Explanation of the columns
1644		2064
1645	I<watcher> is the number of event watchers created/destroyed. Since	2065	I<watcher> is the number of event watchers created/destroyed. Since
1646	different event models feature vastly different performances, each event	2066	different event models feature vastly different performances, each event
…		…
1667	watcher.	2087	watcher.
1668		2088
1669	=head3 Results	2089	=head3 Results
1670		2090
1671	name watchers bytes create invoke destroy comment	2091	name watchers bytes create invoke destroy comment
1672	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2092	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1673	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2093	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1674	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2094	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1675	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2095	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1676	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2096	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1677	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2097	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2098	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2099	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1678	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2100	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1679	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2101	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1680	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2102	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1681	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2103	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1682		2104
1683	=head3 Discussion	2105	=head3 Discussion
1684		2106
1685	The benchmark does I<not> measure scalability of the event loop very	2107	The benchmark does I<not> measure scalability of the event loop very
1686	well. For example, a select-based event loop (such as the pure perl one)	2108	well. For example, a select-based event loop (such as the pure perl one)
…		…
1698	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2120	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1699	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2121	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1700	cycles with POE.	2122	cycles with POE.
1701		2123
1702	C<EV> is the sole leader regarding speed and memory use, which are both	2124	C<EV> is the sole leader regarding speed and memory use, which are both
1703	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2125	maximal/minimal, respectively. When using the L<AE> API there is zero
		2126	overhead (when going through the AnyEvent API create is about 5-6 times
		2127	slower, with other times being equal, so still uses far less memory than
1704	far less memory than any other event loop and is still faster than Event	2128	any other event loop and is still faster than Event natively).
1705	natively.
1706		2129
1707	The pure perl implementation is hit in a few sweet spots (both the	2130	The pure perl implementation is hit in a few sweet spots (both the
1708	constant timeout and the use of a single fd hit optimisations in the perl	2131	constant timeout and the use of a single fd hit optimisations in the perl
1709	interpreter and the backend itself). Nevertheless this shows that it	2132	interpreter and the backend itself). Nevertheless this shows that it
1710	adds very little overhead in itself. Like any select-based backend its	2133	adds very little overhead in itself. Like any select-based backend its
1711	performance becomes really bad with lots of file descriptors (and few of	2134	performance becomes really bad with lots of file descriptors (and few of
1712	them active), of course, but this was not subject of this benchmark.	2135	them active), of course, but this was not subject of this benchmark.
1713		2136
1714	The C<Event> module has a relatively high setup and callback invocation	2137	The C<Event> module has a relatively high setup and callback invocation
1715	cost, but overall scores in on the third place.	2138	cost, but overall scores in on the third place.
		2139
		2140	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2141	when using its pure perl backend.
1716		2142
1717	C<Glib>'s memory usage is quite a bit higher, but it features a	2143	C<Glib>'s memory usage is quite a bit higher, but it features a
1718	faster callback invocation and overall ends up in the same class as	2144	faster callback invocation and overall ends up in the same class as
1719	C<Event>. However, Glib scales extremely badly, doubling the number of	2145	C<Event>. However, Glib scales extremely badly, doubling the number of
1720	watchers increases the processing time by more than a factor of four,	2146	watchers increases the processing time by more than a factor of four,
…		…
1781	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2207	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1782	(1%) are active. This mirrors the activity of large servers with many	2208	(1%) are active. This mirrors the activity of large servers with many
1783	connections, most of which are idle at any one point in time.	2209	connections, most of which are idle at any one point in time.
1784		2210
1785	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2211	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1786	distribution.	2212	distribution. It uses the L<AE> interface, which makes a real difference
		2213	for the EV and Perl backends only.
1787		2214
1788	=head3 Explanation of the columns	2215	=head3 Explanation of the columns
1789		2216
1790	I<sockets> is the number of sockets, and twice the number of "servers" (as	2217	I<sockets> is the number of sockets, and twice the number of "servers" (as
1791	each server has a read and write socket end).	2218	each server has a read and write socket end).
…		…
1798	it to another server. This includes deleting the old timeout and creating	2225	it to another server. This includes deleting the old timeout and creating
1799	a new one that moves the timeout into the future.	2226	a new one that moves the timeout into the future.
1800		2227
1801	=head3 Results	2228	=head3 Results
1802		2229
1803	name sockets create request	2230	name sockets create request
1804	EV 20000 69.01 11.16	2231	EV 20000 62.66 7.99
1805	Perl 20000 73.32 35.87	2232	Perl 20000 68.32 32.64
1806	Event 20000 212.62 257.32	2233	IOAsync 20000 174.06 101.15 epoll
1807	Glib 20000 651.16 1896.30	2234	IOAsync 20000 174.67 610.84 poll
		2235	Event 20000 202.69 242.91
		2236	Glib 20000 557.01 1689.52
1808	POE 20000 349.67 12317.24 uses POE::Loop::Event	2237	POE 20000 341.54 12086.32 uses POE::Loop::Event
1809		2238
1810	=head3 Discussion	2239	=head3 Discussion
1811		2240
1812	This benchmark I<does> measure scalability and overall performance of the	2241	This benchmark I<does> measure scalability and overall performance of the
1813	particular event loop.	2242	particular event loop.
…		…
1815	EV is again fastest. Since it is using epoll on my system, the setup time	2244	EV is again fastest. Since it is using epoll on my system, the setup time
1816	is relatively high, though.	2245	is relatively high, though.
1817		2246
1818	Perl surprisingly comes second. It is much faster than the C-based event	2247	Perl surprisingly comes second. It is much faster than the C-based event
1819	loops Event and Glib.	2248	loops Event and Glib.
		2249
		2250	IO::Async performs very well when using its epoll backend, and still quite
		2251	good compared to Glib when using its pure perl backend.
1820		2252
1821	Event suffers from high setup time as well (look at its code and you will	2253	Event suffers from high setup time as well (look at its code and you will
1822	understand why). Callback invocation also has a high overhead compared to	2254	understand why). Callback invocation also has a high overhead compared to
1823	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2255	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1824	uses select or poll in basically all documented configurations.	2256	uses select or poll in basically all documented configurations.
…		…
1887	=item * C-based event loops perform very well with small number of	2319	=item * C-based event loops perform very well with small number of
1888	watchers, as the management overhead dominates.	2320	watchers, as the management overhead dominates.
1889		2321
1890	=back	2322	=back
1891		2323
		2324	=head2 THE IO::Lambda BENCHMARK
		2325
		2326	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2327	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2328	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2329	shouldn't come as a surprise to anybody). As such, the benchmark is
		2330	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2331	very optimal. But how would AnyEvent compare when used without the extra
		2332	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2333
		2334	The benchmark itself creates an echo-server, and then, for 500 times,
		2335	connects to the echo server, sends a line, waits for the reply, and then
		2336	creates the next connection. This is a rather bad benchmark, as it doesn't
		2337	test the efficiency of the framework or much non-blocking I/O, but it is a
		2338	benchmark nevertheless.
		2339
		2340	name runtime
		2341	Lambda/select 0.330 sec
		2342	+ optimized 0.122 sec
		2343	Lambda/AnyEvent 0.327 sec
		2344	+ optimized 0.138 sec
		2345	Raw sockets/select 0.077 sec
		2346	POE/select, components 0.662 sec
		2347	POE/select, raw sockets 0.226 sec
		2348	POE/select, optimized 0.404 sec
		2349
		2350	AnyEvent/select/nb 0.085 sec
		2351	AnyEvent/EV/nb 0.068 sec
		2352	+state machine 0.134 sec
		2353
		2354	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2355	benchmarks actually make blocking connects and use 100% blocking I/O,
		2356	defeating the purpose of an event-based solution. All of the newly
		2357	written AnyEvent benchmarks use 100% non-blocking connects (using
		2358	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2359	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2360	generally require a lot more bookkeeping and event handling than blocking
		2361	connects (which involve a single syscall only).
		2362
		2363	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2364	offers similar expressive power as POE and IO::Lambda, using conventional
		2365	Perl syntax. This means that both the echo server and the client are 100%
		2366	non-blocking, further placing it at a disadvantage.
		2367
		2368	As you can see, the AnyEvent + EV combination even beats the
		2369	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2370	backend easily beats IO::Lambda and POE.
		2371
		2372	And even the 100% non-blocking version written using the high-level (and
		2373	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2374	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2375	in a non-blocking way.
		2376
		2377	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2378	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2379	part of the IO::lambda distribution and were used without any changes.
		2380
1892		2381
1893	=head1 SIGNALS	2382	=head1 SIGNALS
1894		2383
1895	AnyEvent currently installs handlers for these signals:	2384	AnyEvent currently installs handlers for these signals:
1896		2385
…		…
1899	=item SIGCHLD	2388	=item SIGCHLD
1900		2389
1901	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2390	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1902	emulation for event loops that do not support them natively. Also, some	2391	emulation for event loops that do not support them natively. Also, some
1903	event loops install a similar handler.	2392	event loops install a similar handler.
		2393
		2394	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2395	AnyEvent will reset it to default, to avoid losing child exit statuses.
1904		2396
1905	=item SIGPIPE	2397	=item SIGPIPE
1906		2398
1907	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2399	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1908	when AnyEvent gets loaded.	2400	when AnyEvent gets loaded.
…		…
1920		2412
1921	=back	2413	=back
1922		2414
1923	=cut	2415	=cut
1924		2416
		2417	undef $SIG{CHLD}
		2418	if $SIG{CHLD} eq 'IGNORE';
		2419
1925	$SIG{PIPE} = sub { }	2420	$SIG{PIPE} = sub { }
1926	unless defined $SIG{PIPE};	2421	unless defined $SIG{PIPE};
		2422
		2423	=head1 RECOMMENDED/OPTIONAL MODULES
		2424
		2425	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2426	it's built-in modules) are required to use it.
		2427
		2428	That does not mean that AnyEvent won't take advantage of some additional
		2429	modules if they are installed.
		2430
		2431	This section epxlains which additional modules will be used, and how they
		2432	affect AnyEvent's operetion.
		2433
		2434	=over 4
		2435
		2436	=item L<Async::Interrupt>
		2437
		2438	This slightly arcane module is used to implement fast signal handling: To
		2439	my knowledge, there is no way to do completely race-free and quick
		2440	signal handling in pure perl. To ensure that signals still get
		2441	delivered, AnyEvent will start an interval timer to wake up perl (and
		2442	catch the signals) with some delay (default is 10 seconds, look for
		2443	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2444
		2445	If this module is available, then it will be used to implement signal
		2446	catching, which means that signals will not be delayed, and the event loop
		2447	will not be interrupted regularly, which is more efficient (And good for
		2448	battery life on laptops).
		2449
		2450	This affects not just the pure-perl event loop, but also other event loops
		2451	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2452
		2453	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2454	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2455	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2456	does nothing for those backends.
		2457
		2458	=item L<EV>
		2459
		2460	This module isn't really "optional", as it is simply one of the backend
		2461	event loops that AnyEvent can use. However, it is simply the best event
		2462	loop available in terms of features, speed and stability: It supports
		2463	the AnyEvent API optimally, implements all the watcher types in XS, does
		2464	automatic timer adjustments even when no monotonic clock is available,
		2465	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2466	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2467	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2468
		2469	=item L<Guard>
		2470
		2471	The guard module, when used, will be used to implement
		2472	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2473	lot less memory), but otherwise doesn't affect guard operation much. It is
		2474	purely used for performance.
		2475
		2476	=item L<JSON> and L<JSON::XS>
		2477
		2478	This module is required when you want to read or write JSON data via
		2479	L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2480	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2481
		2482	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2483	installed.
		2484
		2485	=item L<Net::SSLeay>
		2486
		2487	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2488	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2489	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2490
		2491	=item L<Time::HiRes>
		2492
		2493	This module is part of perl since release 5.008. It will be used when the
		2494	chosen event library does not come with a timing source on it's own. The
		2495	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2496	try to use a monotonic clock for timing stability.
		2497
		2498	=back
1927		2499
1928		2500
1929	=head1 FORK	2501	=head1 FORK
1930		2502
1931	Most event libraries are not fork-safe. The ones who are usually are	2503	Most event libraries are not fork-safe. The ones who are usually are
1932	because they rely on inefficient but fork-safe C<select> or C<poll>	2504	because they rely on inefficient but fork-safe C<select> or C<poll>
1933	calls. Only L<EV> is fully fork-aware.	2505	calls. Only L<EV> is fully fork-aware.
1934		2506
1935	If you have to fork, you must either do so I<before> creating your first	2507	If you have to fork, you must either do so I<before> creating your first
1936	watcher OR you must not use AnyEvent at all in the child.	2508	watcher OR you must not use AnyEvent at all in the child OR you must do
		2509	something completely out of the scope of AnyEvent.
1937		2510
1938		2511
1939	=head1 SECURITY CONSIDERATIONS	2512	=head1 SECURITY CONSIDERATIONS
1940		2513
1941	AnyEvent can be forced to load any event model via	2514	AnyEvent can be forced to load any event model via
…		…
1955	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2528	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1956	be used to probe what backend is used and gain other information (which is	2529	be used to probe what backend is used and gain other information (which is
1957	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2530	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1958	$ENV{PERL_ANYEVENT_STRICT}.	2531	$ENV{PERL_ANYEVENT_STRICT}.
1959		2532
		2533	Note that AnyEvent will remove I<all> environment variables starting with
		2534	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2535	enabled.
		2536
1960		2537
1961	=head1 BUGS	2538	=head1 BUGS
1962		2539
1963	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2540	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1964	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2541	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
…		…
1975	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2552	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1976		2553
1977	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2554	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1978	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2555	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1979	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2556	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1980	L<AnyEvent::Impl::POE>.	2557	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1981		2558
1982	Non-blocking file handles, sockets, TCP clients and	2559	Non-blocking file handles, sockets, TCP clients and
1983	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2560	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1984		2561
1985	Asynchronous DNS: L<AnyEvent::DNS>.	2562	Asynchronous DNS: L<AnyEvent::DNS>.
1986		2563
1987	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2564	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2565	L<Coro::Event>,
1988		2566
1989	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2567	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2568	L<AnyEvent::HTTP>.
1990		2569
1991		2570
1992	=head1 AUTHOR	2571	=head1 AUTHOR
1993		2572
1994	Marc Lehmann <schmorp@schmorp.de>	2573	Marc Lehmann <schmorp@schmorp.de>

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