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Revision 1.303 by root, Sat Dec 5 02:52:03 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
…		…
341	might affect timers and time-outs.	363	might affect timers and time-outs.
342		364
343	When this is the case, you can call this method, which will update the	365	When this is the case, you can call this method, which will update the
344	event loop's idea of "current time".	366	event loop's idea of "current time".
345		367
		368	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		369	when mod_perl executes the script, then the event loop will have the wrong
		370	idea about the "current time" (being potentially far in the past, when the
		371	script ran the last time). In that case you should arrange a call to C<<
		372	AnyEvent->now_update >> each time the web server process wakes up again
		373	(e.g. at the start of your script, or in a handler).
		374
346	Note that updating the time I<might> cause some events to be handled.	375	Note that updating the time I<might> cause some events to be handled.
347		376
348	=back	377	=back
349		378
350	=head2 SIGNAL WATCHERS	379	=head2 SIGNAL WATCHERS
		380
		381	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351		382
352	You can watch for signals using a signal watcher, C<signal> is the signal	383	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	384	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354	callback to be invoked whenever a signal occurs.	385	callback to be invoked whenever a signal occurs.
355		386
…		…
361	invocation, and callback invocation will be synchronous. Synchronous means	392	invocation, and callback invocation will be synchronous. Synchronous means
362	that it might take a while until the signal gets handled by the process,	393	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.	394	but it is guaranteed not to interrupt any other callbacks.
364		395
365	The main advantage of using these watchers is that you can share a signal	396	The main advantage of using these watchers is that you can share a signal
366	between multiple watchers.	397	between multiple watchers, and AnyEvent will ensure that signals will not
		398	interrupt your program at bad times.
367		399
368	This watcher might use C<%SIG>, so programs overwriting those signals	400	This watcher might use C<%SIG> (depending on the event loop used),
369	directly will likely not work correctly.	401	so programs overwriting those signals directly will likely not work
		402	correctly.
370		403
371	Example: exit on SIGINT	404	Example: exit on SIGINT
372		405
373	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	406	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
374		407
		408	=head3 Restart Behaviour
		409
		410	While restart behaviour is up to the event loop implementation, most will
		411	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		412	pure perl implementation).
		413
		414	=head3 Safe/Unsafe Signals
		415
		416	Perl signals can be either "safe" (synchronous to opcode handling) or
		417	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		418	latter might corrupt your memory.
		419
		420	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		421	i.e. they will not interrupt your running perl program but will only be
		422	called as part of the normal event handling (just like timer, I/O etc.
		423	callbacks, too).
		424
		425	=head3 Signal Races, Delays and Workarounds
		426
		427	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		428	callbacks to signals in a generic way, which is a pity, as you cannot
		429	do race-free signal handling in perl, requiring C libraries for
		430	this. AnyEvent will try to do it's best, which means in some cases,
		431	signals will be delayed. The maximum time a signal might be delayed is
		432	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		433	variable can be changed only before the first signal watcher is created,
		434	and should be left alone otherwise. This variable determines how often
		435	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		436	will cause fewer spurious wake-ups, which is better for power and CPU
		437	saving.
		438
		439	All these problems can be avoided by installing the optional
		440	L<Async::Interrupt> module, which works with most event loops. It will not
		441	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		442	(and not with L<POE> currently, as POE does it's own workaround with
		443	one-second latency). For those, you just have to suffer the delays.
		444
375	=head2 CHILD PROCESS WATCHERS	445	=head2 CHILD PROCESS WATCHERS
376		446
		447	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		448
377	You can also watch on a child process exit and catch its exit status.	449	You can also watch on a child process exit and catch its exit status.
378		450
379	The child process is specified by the C<pid> argument (if set to C<0>, it	451	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	452	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	453	croak). The watcher will be triggered only when the child process has
382	any trace events (stopped/continued).	454	finished and an exit status is available, not on any trace events
		455	(stopped/continued).
383		456
384	The callback will be called with the pid and exit status (as returned by	457	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	458	waitpid), so unlike other watcher types, you I<can> rely on child watcher
386	callback arguments.	459	callback arguments.
387		460
…		…
392		465
393	There is a slight catch to child watchers, however: you usually start them	466	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	467	I<after> the child process was created, and this means the process could
395	have exited already (and no SIGCHLD will be sent anymore).	468	have exited already (and no SIGCHLD will be sent anymore).
396		469
397	Not all event models handle this correctly (POE doesn't), but even for	470	Not all event models handle this correctly (neither POE nor IO::Async do,
		471	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	472	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).	473	the process exits (i.e. before you fork in the first place). AnyEvent's
		474	pure perl event loop handles all cases correctly regardless of when you
		475	start the watcher.
400		476
401	This means you cannot create a child watcher as the very first thing in an	477	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	478	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>).	479	watcher before you C<fork> the child (alternatively, you can call
		480	C<AnyEvent::detect>).
		481
		482	As most event loops do not support waiting for child events, they will be
		483	emulated by AnyEvent in most cases, in which the latency and race problems
		484	mentioned in the description of signal watchers apply.
404		485
405	Example: fork a process and wait for it	486	Example: fork a process and wait for it
406		487
407	my $done = AnyEvent->condvar;	488	my $done = AnyEvent->condvar;
408		489
…		…
420	# do something else, then wait for process exit	501	# do something else, then wait for process exit
421	$done->recv;	502	$done->recv;
422		503
423	=head2 IDLE WATCHERS	504	=head2 IDLE WATCHERS
424		505
		506	$w = AnyEvent->idle (cb => <callback>);
		507
425	Sometimes there is a need to do something, but it is not so important	508	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	509	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	510	"nothing better to do" is usually defined to be "no other events need
428	attention by the event loop".	511	attention by the event loop".
429		512
…		…
455	});	538	});
456	});	539	});
457		540
458	=head2 CONDITION VARIABLES	541	=head2 CONDITION VARIABLES
459		542
		543	$cv = AnyEvent->condvar;
		544
		545	$cv->send (<list>);
		546	my @res = $cv->recv;
		547
460	If you are familiar with some event loops you will know that all of them	548	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	549	require you to run some blocking "loop", "run" or similar function that
462	will actively watch for new events and call your callbacks.	550	will actively watch for new events and call your callbacks.
463		551
464	AnyEvent is different, it expects somebody else to run the event loop and	552	AnyEvent is slightly different: it expects somebody else to run the event
465	will only block when necessary (usually when told by the user).	553	loop and will only block when necessary (usually when told by the user).
466		554
467	The instrument to do that is called a "condition variable", so called	555	The instrument to do that is called a "condition variable", so called
468	because they represent a condition that must become true.	556	because they represent a condition that must become true.
469		557
		558	Now is probably a good time to look at the examples further below.
		559
470	Condition variables can be created by calling the C<< AnyEvent->condvar	560	Condition variables can be created by calling the C<< AnyEvent->condvar
471	>> method, usually without arguments. The only argument pair allowed is	561	>> 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	562	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	563	becomes true, with the condition variable as the first argument (but not
475	the results).	564	the results).
476		565
477	After creation, the condition variable is "false" until it becomes "true"	566	After creation, the condition variable is "false" until it becomes "true"
…		…
482	Condition variables are similar to callbacks, except that you can	571	Condition variables are similar to callbacks, except that you can
483	optionally wait for them. They can also be called merge points - points	572	optionally wait for them. They can also be called merge points - points
484	in time where multiple outstanding events have been processed. And yet	573	in time where multiple outstanding events have been processed. And yet
485	another way to call them is transactions - each condition variable can be	574	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	575	used to represent a transaction, which finishes at some point and delivers
487	a result.	576	a result. And yet some people know them as "futures" - a promise to
		577	compute/deliver something that you can wait for.
488		578
489	Condition variables are very useful to signal that something has finished,	579	Condition variables are very useful to signal that something has finished,
490	for example, if you write a module that does asynchronous http requests,	580	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	581	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	582	availability of results. The user can either act when the callback is
…		…
526	after => 1,	616	after => 1,
527	cb => sub { $result_ready->send },	617	cb => sub { $result_ready->send },
528	);	618	);
529		619
530	# this "blocks" (while handling events) till the callback	620	# this "blocks" (while handling events) till the callback
531	# calls send	621	# calls ->send
532	$result_ready->recv;	622	$result_ready->recv;
533		623
534	Example: wait for a timer, but take advantage of the fact that	624	Example: wait for a timer, but take advantage of the fact that condition
535	condition variables are also code references.	625	variables are also callable directly.
536		626
537	my $done = AnyEvent->condvar;	627	my $done = AnyEvent->condvar;
538	my $delay = AnyEvent->timer (after => 5, cb => $done);	628	my $delay = AnyEvent->timer (after => 5, cb => $done);
539	$done->recv;	629	$done->recv;
540		630
…		…
546		636
547	...	637	...
548		638
549	my @info = $couchdb->info->recv;	639	my @info = $couchdb->info->recv;
550		640
551	And this is how you would just ste a callback to be called whenever the	641	And this is how you would just set a callback to be called whenever the
552	results are available:	642	results are available:
553		643
554	$couchdb->info->cb (sub {	644	$couchdb->info->cb (sub {
555	my @info = $_[0]->recv;	645	my @info = $_[0]->recv;
556	});	646	});
…		…
574	immediately from within send.	664	immediately from within send.
575		665
576	Any arguments passed to the C<send> call will be returned by all	666	Any arguments passed to the C<send> call will be returned by all
577	future C<< ->recv >> calls.	667	future C<< ->recv >> calls.
578		668
579	Condition variables are overloaded so one can call them directly	669	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	670	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	671	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		672
588	=item $cv->croak ($error)	673	=item $cv->croak ($error)
589		674
590	Similar to send, but causes all call's to C<< ->recv >> to invoke	675	Similar to send, but causes all call's to C<< ->recv >> to invoke
591	C<Carp::croak> with the given error message/object/scalar.	676	C<Carp::croak> with the given error message/object/scalar.
592		677
593	This can be used to signal any errors to the condition variable	678	This can be used to signal any errors to the condition variable
594	user/consumer.	679	user/consumer. Doing it this way instead of calling C<croak> directly
		680	delays the error detetcion, but has the overwhelmign advantage that it
		681	diagnoses the error at the place where the result is expected, and not
		682	deep in some event clalback without connection to the actual code causing
		683	the problem.
595		684
596	=item $cv->begin ([group callback])	685	=item $cv->begin ([group callback])
597		686
598	=item $cv->end	687	=item $cv->end
599
600	These two methods are EXPERIMENTAL and MIGHT CHANGE.
601		688
602	These two methods can be used to combine many transactions/events into	689	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	690	one. For example, a function that pings many hosts in parallel might want
604	to use a condition variable for the whole process.	691	to use a condition variable for the whole process.
605		692
606	Every call to C<< ->begin >> will increment a counter, and every call to	693	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	694	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	695	>>, 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	696	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.	697	>>, but that is not required. If no group callback was set, C<send> will
		698	be called without any arguments.
611		699
612	Let's clarify this with the ping example:	700	You can think of C<< $cv->send >> giving you an OR condition (one call
		701	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		702	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		703
		704	Let's start with a simple example: you have two I/O watchers (for example,
		705	STDOUT and STDERR for a program), and you want to wait for both streams to
		706	close before activating a condvar:
613		707
614	my $cv = AnyEvent->condvar;	708	my $cv = AnyEvent->condvar;
615		709
		710	$cv->begin; # first watcher
		711	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		712	defined sysread $fh1, my $buf, 4096
		713	or $cv->end;
		714	});
		715
		716	$cv->begin; # second watcher
		717	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		718	defined sysread $fh2, my $buf, 4096
		719	or $cv->end;
		720	});
		721
		722	$cv->recv;
		723
		724	This works because for every event source (EOF on file handle), there is
		725	one call to C<begin>, so the condvar waits for all calls to C<end> before
		726	sending.
		727
		728	The ping example mentioned above is slightly more complicated, as the
		729	there are results to be passwd back, and the number of tasks that are
		730	begung can potentially be zero:
		731
		732	my $cv = AnyEvent->condvar;
		733
616	my %result;	734	my %result;
617	$cv->begin (sub { $cv->send (\%result) });	735	$cv->begin (sub { shift->send (\%result) });
618		736
619	for my $host (@list_of_hosts) {	737	for my $host (@list_of_hosts) {
620	$cv->begin;	738	$cv->begin;
621	ping_host_then_call_callback $host, sub {	739	ping_host_then_call_callback $host, sub {
622	$result{$host} = ...;	740	$result{$host} = ...;
…		…
637	loop, which serves two important purposes: first, it sets the callback	755	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	756	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	757	C<send> is called even when C<no> hosts are being pinged (the loop
640	doesn't execute once).	758	doesn't execute once).
641		759
642	This is the general pattern when you "fan out" into multiple subrequests:	760	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>	761	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	762	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>.	763	subrequest you start, call C<begin> and for each subrequest you finish,
		764	call C<end>.
646		765
647	=back	766	=back
648		767
649	=head3 METHODS FOR CONSUMERS	768	=head3 METHODS FOR CONSUMERS
650		769
…		…
666	function will call C<croak>.	785	function will call C<croak>.
667		786
668	In list context, all parameters passed to C<send> will be returned,	787	In list context, all parameters passed to C<send> will be returned,
669	in scalar context only the first one will be returned.	788	in scalar context only the first one will be returned.
670		789
		790	Note that doing a blocking wait in a callback is not supported by any
		791	event loop, that is, recursive invocation of a blocking C<< ->recv
		792	>> is not allowed, and the C<recv> call will C<croak> if such a
		793	condition is detected. This condition can be slightly loosened by using
		794	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		795	any thread that doesn't run the event loop itself.
		796
671	Not all event models support a blocking wait - some die in that case	797	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	798	(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	799	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	800	caller decide whether the call will block or not (for example, by coupling
675	condition variables with some kind of request results and supporting	801	condition variables with some kind of request results and supporting
676	callbacks so the caller knows that getting the result will not block,	802	callbacks so the caller knows that getting the result will not block,
677	while still supporting blocking waits if the caller so desires).	803	while still supporting blocking waits if the caller so desires).
678		804
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	805	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	806	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	807	time). This will work even when the event loop does not support blocking
693	waits otherwise.	808	waits otherwise.
694		809
…		…
700	=item $cb = $cv->cb ($cb->($cv))	815	=item $cb = $cv->cb ($cb->($cv))
701		816
702	This is a mutator function that returns the callback set and optionally	817	This is a mutator function that returns the callback set and optionally
703	replaces it before doing so.	818	replaces it before doing so.
704		819
705	The callback will be called when the condition becomes "true", i.e. when	820	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	821	"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	822	the only argument being the condition variable itself. Calling C<recv>
708	is guaranteed not to block.	823	inside the callback or at any later time is guaranteed not to block.
709		824
710	=back	825	=back
711		826
		827	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		828
		829	The available backend classes are (every class has its own manpage):
		830
		831	=over 4
		832
		833	=item Backends that are autoprobed when no other event loop can be found.
		834
		835	EV is the preferred backend when no other event loop seems to be in
		836	use. If EV is not installed, then AnyEvent will fall back to its own
		837	pure-perl implementation, which is available everywhere as it comes with
		838	AnyEvent itself.
		839
		840	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		841	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		842
		843	=item Backends that are transparently being picked up when they are used.
		844
		845	These will be used when they are currently loaded when the first watcher
		846	is created, in which case it is assumed that the application is using
		847	them. This means that AnyEvent will automatically pick the right backend
		848	when the main program loads an event module before anything starts to
		849	create watchers. Nothing special needs to be done by the main program.
		850
		851	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		852	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		853	AnyEvent::Impl::Tk based on Tk, very broken.
		854	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		855	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		856	AnyEvent::Impl::Irssi used when running within irssi.
		857
		858	=item Backends with special needs.
		859
		860	Qt requires the Qt::Application to be instantiated first, but will
		861	otherwise be picked up automatically. As long as the main program
		862	instantiates the application before any AnyEvent watchers are created,
		863	everything should just work.
		864
		865	AnyEvent::Impl::Qt based on Qt.
		866
		867	Support for IO::Async can only be partial, as it is too broken and
		868	architecturally limited to even support the AnyEvent API. It also
		869	is the only event loop that needs the loop to be set explicitly, so
		870	it can only be used by a main program knowing about AnyEvent. See
		871	L<AnyEvent::Impl::Async> for the gory details.
		872
		873	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		874
		875	=item Event loops that are indirectly supported via other backends.
		876
		877	Some event loops can be supported via other modules:
		878
		879	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		880
		881	B<WxWidgets> has no support for watching file handles. However, you can
		882	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		883	polls 20 times per second, which was considered to be too horrible to even
		884	consider for AnyEvent.
		885
		886	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		887	backend, so it can be supported through POE.
		888
		889	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		890	load L<POE> when detecting them, in the hope that POE will pick them up,
		891	in which case everything will be automatic.
		892
		893	=back
		894
712	=head1 GLOBAL VARIABLES AND FUNCTIONS	895	=head1 GLOBAL VARIABLES AND FUNCTIONS
713		896
		897	These are not normally required to use AnyEvent, but can be useful to
		898	write AnyEvent extension modules.
		899
714	=over 4	900	=over 4
715		901
716	=item $AnyEvent::MODEL	902	=item $AnyEvent::MODEL
717		903
718	Contains C<undef> until the first watcher is being created. Then it	904	Contains C<undef> until the first watcher is being created, before the
		905	backend has been autodetected.
		906
719	contains the event model that is being used, which is the name of the	907	Afterwards it contains the event model that is being used, which is the
720	Perl class implementing the model. This class is usually one of the	908	name of the Perl class implementing the model. This class is usually one
721	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	909	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
722	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	910	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
723		911	will be C<urxvt::anyevent>).
724	The known classes so far are:
725
726	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
727	AnyEvent::Impl::Event based on Event, second best choice.
728	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
729	AnyEvent::Impl::Glib based on Glib, third-best choice.
730	AnyEvent::Impl::Tk based on Tk, very bad choice.
731	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
732	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
733	AnyEvent::Impl::POE based on POE, not generic enough for full support.
734
735	There is no support for WxWidgets, as WxWidgets has no support for
736	watching file handles. However, you can use WxWidgets through the
737	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
738	second, which was considered to be too horrible to even consider for
739	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
740	it's adaptor.
741
742	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
743	autodetecting them.
744		912
745	=item AnyEvent::detect	913	=item AnyEvent::detect
746		914
747	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	915	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
748	if necessary. You should only call this function right before you would	916	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	917	have created an AnyEvent watcher anyway, that is, as late as possible at
750	runtime.	918	runtime, and not e.g. while initialising of your module.
		919
		920	If you need to do some initialisation before AnyEvent watchers are
		921	created, use C<post_detect>.
751		922
752	=item $guard = AnyEvent::post_detect { BLOCK }	923	=item $guard = AnyEvent::post_detect { BLOCK }
753		924
754	Arranges for the code block to be executed as soon as the event model is	925	Arranges for the code block to be executed as soon as the event model is
755	autodetected (or immediately if this has already happened).	926	autodetected (or immediately if this has already happened).
756		927
		928	The block will be executed I<after> the actual backend has been detected
		929	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		930	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		931	other initialisations - see the sources of L<AnyEvent::Strict> or
		932	L<AnyEvent::AIO> to see how this is used.
		933
		934	The most common usage is to create some global watchers, without forcing
		935	event module detection too early, for example, L<AnyEvent::AIO> creates
		936	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		937	avoid autodetecting the event module at load time.
		938
757	If called in scalar or list context, then it creates and returns an object	939	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	940	that automatically removes the callback again when it is destroyed (or
		941	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
759	L<Coro::BDB> for a case where this is useful.	942	a case where this is useful.
		943
		944	Example: Create a watcher for the IO::AIO module and store it in
		945	C<$WATCHER>. Only do so after the event loop is initialised, though.
		946
		947	our WATCHER;
		948
		949	my $guard = AnyEvent::post_detect {
		950	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		951	};
		952
		953	# the ||= is important in case post_detect immediately runs the block,
		954	# as to not clobber the newly-created watcher. assigning both watcher and
		955	# post_detect guard to the same variable has the advantage of users being
		956	# able to just C<undef $WATCHER> if the watcher causes them grief.
		957
		958	$WATCHER ||= $guard;
760		959
761	=item @AnyEvent::post_detect	960	=item @AnyEvent::post_detect
762		961
763	If there are any code references in this array (you can C<push> to it	962	If there are any code references in this array (you can C<push> to it
764	before or after loading AnyEvent), then they will called directly after	963	before or after loading AnyEvent), then they will called directly after
765	the event loop has been chosen.	964	the event loop has been chosen.
766		965
767	You should check C<$AnyEvent::MODEL> before adding to this array, though:	966	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,	967	if it is defined then the event loop has already been detected, and the
769	and the array will be ignored.	968	array will be ignored.
770		969
771	Best use C<AnyEvent::post_detect { BLOCK }> instead.	970	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		971	it,as it takes care of these details.
		972
		973	This variable is mainly useful for modules that can do something useful
		974	when AnyEvent is used and thus want to know when it is initialised, but do
		975	not need to even load it by default. This array provides the means to hook
		976	into AnyEvent passively, without loading it.
772		977
773	=back	978	=back
774		979
775	=head1 WHAT TO DO IN A MODULE	980	=head1 WHAT TO DO IN A MODULE
776		981
…		…
831		1036
832		1037
833	=head1 OTHER MODULES	1038	=head1 OTHER MODULES
834		1039
835	The following is a non-exhaustive list of additional modules that use	1040	The following is a non-exhaustive list of additional modules that use
836	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1041	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	1042	modules and other event loops in the same program. Some of the modules
838	available via CPAN.	1043	come with AnyEvent, most are available via CPAN.
839		1044
840	=over 4	1045	=over 4
841		1046
842	=item L<AnyEvent::Util>	1047	=item L<AnyEvent::Util>
843		1048
…		…
852		1057
853	=item L<AnyEvent::Handle>	1058	=item L<AnyEvent::Handle>
854		1059
855	Provide read and write buffers, manages watchers for reads and writes,	1060	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	1061	supports raw and formatted I/O, I/O queued and fully transparent and
857	non-blocking SSL/TLS.	1062	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
858		1063
859	=item L<AnyEvent::DNS>	1064	=item L<AnyEvent::DNS>
860		1065
861	Provides rich asynchronous DNS resolver capabilities.	1066	Provides rich asynchronous DNS resolver capabilities.
862		1067
…		…
890		1095
891	=item L<AnyEvent::GPSD>	1096	=item L<AnyEvent::GPSD>
892		1097
893	A non-blocking interface to gpsd, a daemon delivering GPS information.	1098	A non-blocking interface to gpsd, a daemon delivering GPS information.
894		1099
		1100	=item L<AnyEvent::IRC>
		1101
		1102	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1103
		1104	=item L<AnyEvent::XMPP>
		1105
		1106	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1107	Net::XMPP2>.
		1108
895	=item L<AnyEvent::IGS>	1109	=item L<AnyEvent::IGS>
896		1110
897	A non-blocking interface to the Internet Go Server protocol (used by	1111	A non-blocking interface to the Internet Go Server protocol (used by
898	L<App::IGS>).	1112	L<App::IGS>).
899		1113
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>	1114	=item L<Net::FCP>
909		1115
910	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1116	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
911	of AnyEvent.	1117	of AnyEvent.
912		1118
…		…
916		1122
917	=item L<Coro>	1123	=item L<Coro>
918		1124
919	Has special support for AnyEvent via L<Coro::AnyEvent>.	1125	Has special support for AnyEvent via L<Coro::AnyEvent>.
920		1126
921	=item L<IO::Lambda>
922
923	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
924
925	=back	1127	=back
926		1128
927	=cut	1129	=cut
928		1130
929	package AnyEvent;	1131	package AnyEvent;
930		1132
931	no warnings;	1133	# basically a tuned-down version of common::sense
		1134	sub common_sense {
		1135	# from common:.sense 1.0
		1136	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x03";
932	use strict qw(vars subs);	1137	# use strict vars subs
		1138	$^H |= 0x00000600;
		1139	}
933		1140
		1141	BEGIN { AnyEvent::common_sense }
		1142
934	use Carp;	1143	use Carp ();
935		1144
936	our $VERSION = 4.411;	1145	our $VERSION = '5.22';
937	our $MODEL;	1146	our $MODEL;
938		1147
939	our $AUTOLOAD;	1148	our $AUTOLOAD;
940	our @ISA;	1149	our @ISA;
941		1150
942	our @REGISTRY;	1151	our @REGISTRY;
943		1152
944	our $WIN32;	1153	our $VERBOSE;
945		1154
946	BEGIN {	1155	BEGIN {
947	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1156	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
948	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1157	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
949		1158
950	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1159	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
951	if ${^TAINT};	1160	if ${^TAINT};
952	}
953		1161
954	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1162	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1163
		1164	}
		1165
		1166	our $MAX_SIGNAL_LATENCY = 10;
955		1167
956	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1168	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
957		1169
958	{	1170	{
959	my $idx;	1171	my $idx;
…		…
961	for reverse split /\s*,\s*/,	1173	for reverse split /\s*,\s*/,
962	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1174	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
963	}	1175	}
964		1176
965	my @models = (	1177	my @models = (
966	[EV:: => AnyEvent::Impl::EV::],	1178	[EV:: => AnyEvent::Impl::EV:: , 1],
967	[Event:: => AnyEvent::Impl::Event::],
968	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1179	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
969	# everything below here will not be autoprobed	1180	# everything below here will not (normally) be autoprobed
970	# as the pureperl backend should work everywhere	1181	# as the pureperl backend should work everywhere
971	# and is usually faster	1182	# and is usually faster
		1183	[Event:: => AnyEvent::Impl::Event::, 1],
		1184	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1185	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1186	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
972	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1187	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
973	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
974	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
975	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1188	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
976	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1189	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
977	[Wx:: => AnyEvent::Impl::POE::],	1190	[Wx:: => AnyEvent::Impl::POE::],
978	[Prima:: => AnyEvent::Impl::POE::],	1191	[Prima:: => AnyEvent::Impl::POE::],
		1192	# IO::Async is just too broken - we would need workarounds for its
		1193	# byzantine signal and broken child handling, among others.
		1194	# IO::Async is rather hard to detect, as it doesn't have any
		1195	# obvious default class.
		1196	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1197	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1198	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1199	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
979	);	1200	);
980		1201
981	our %method = map +($_ => 1),	1202	our %method = map +($_ => 1),
982	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1203	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
983		1204
…		…
987	my ($cb) = @_;	1208	my ($cb) = @_;
988		1209
989	if ($MODEL) {	1210	if ($MODEL) {
990	$cb->();	1211	$cb->();
991		1212
992	1	1213	undef
993	} else {	1214	} else {
994	push @post_detect, $cb;	1215	push @post_detect, $cb;
995		1216
996	defined wantarray	1217	defined wantarray
997	? bless \$cb, "AnyEvent::Util::postdetect"	1218	? bless \$cb, "AnyEvent::Util::postdetect"
…		…
1003	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1224	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1004	}	1225	}
1005		1226
1006	sub detect() {	1227	sub detect() {
1007	unless ($MODEL) {	1228	unless ($MODEL) {
1008	no strict 'refs';
1009	local $SIG{__DIE__};	1229	local $SIG{__DIE__};
1010		1230
1011	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1231	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1012	my $model = "AnyEvent::Impl::$1";	1232	my $model = "AnyEvent::Impl::$1";
1013	if (eval "require $model") {	1233	if (eval "require $model") {
1014	$MODEL = $model;	1234	$MODEL = $model;
1015	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1235	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1016	} else {	1236	} else {
1017	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1237	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1018	}	1238	}
1019	}	1239	}
1020		1240
1021	# check for already loaded models	1241	# check for already loaded models
1022	unless ($MODEL) {	1242	unless ($MODEL) {
1023	for (@REGISTRY, @models) {	1243	for (@REGISTRY, @models) {
1024	my ($package, $model) = @$_;	1244	my ($package, $model) = @$_;
1025	if (${"$package\::VERSION"} > 0) {	1245	if (${"$package\::VERSION"} > 0) {
1026	if (eval "require $model") {	1246	if (eval "require $model") {
1027	$MODEL = $model;	1247	$MODEL = $model;
1028	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1248	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1029	last;	1249	last;
1030	}	1250	}
1031	}	1251	}
1032	}	1252	}
1033		1253
1034	unless ($MODEL) {	1254	unless ($MODEL) {
1035	# try to load a model	1255	# try to autoload a model
1036
1037	for (@REGISTRY, @models) {	1256	for (@REGISTRY, @models) {
1038	my ($package, $model) = @$_;	1257	my ($package, $model, $autoload) = @$_;
		1258	if (
		1259	$autoload
1039	if (eval "require $package"	1260	and eval "require $package"
1040	and ${"$package\::VERSION"} > 0	1261	and ${"$package\::VERSION"} > 0
1041	and eval "require $model") {	1262	and eval "require $model"
		1263	) {
1042	$MODEL = $model;	1264	$MODEL = $model;
1043	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1265	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1044	last;	1266	last;
1045	}	1267	}
1046	}	1268	}
1047		1269
1048	$MODEL	1270	$MODEL
…		…
1064		1286
1065	sub AUTOLOAD {	1287	sub AUTOLOAD {
1066	(my $func = $AUTOLOAD) =~ s/.*://;	1288	(my $func = $AUTOLOAD) =~ s/.*://;
1067		1289
1068	$method{$func}	1290	$method{$func}
1069	or croak "$func: not a valid method for AnyEvent objects";	1291	or Carp::croak "$func: not a valid method for AnyEvent objects";
1070		1292
1071	detect unless $MODEL;	1293	detect unless $MODEL;
1072		1294
1073	my $class = shift;	1295	my $class = shift;
1074	$class->$func (@_);	1296	$class->$func (@_);
1075	}	1297	}
1076		1298
1077	# utility function to dup a filehandle. this is used by many backends	1299	# utility function to dup a filehandle. this is used by many backends
1078	# to support binding more than one watcher per filehandle (they usually	1300	# to support binding more than one watcher per filehandle (they usually
1079	# allow only one watcher per fd, so we dup it to get a different one).	1301	# allow only one watcher per fd, so we dup it to get a different one).
1080	sub _dupfh($$$$) {	1302	sub _dupfh($$;$$) {
1081	my ($poll, $fh, $r, $w) = @_;	1303	my ($poll, $fh, $r, $w) = @_;
1082		1304
1083	# cygwin requires the fh mode to be matching, unix doesn't	1305	# cygwin requires the fh mode to be matching, unix doesn't
1084	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1306	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1085	: $poll eq "w" ? ($w, ">")
1086	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1087		1307
1088	open my $fh2, "$mode&" . fileno $fh	1308	open my $fh2, $mode, $fh
1089	or die "cannot dup() filehandle: $!,";	1309	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1090		1310
1091	# we assume CLOEXEC is already set by perl in all important cases	1311	# we assume CLOEXEC is already set by perl in all important cases
1092		1312
1093	($fh2, $rw)	1313	($fh2, $rw)
1094	}	1314	}
1095		1315
		1316	=head1 SIMPLIFIED AE API
		1317
		1318	Starting with version 5.0, AnyEvent officially supports a second, much
		1319	simpler, API that is designed to reduce the calling, typing and memory
		1320	overhead.
		1321
		1322	See the L<AE> manpage for details.
		1323
		1324	=cut
		1325
		1326	package AE;
		1327
		1328	our $VERSION = $AnyEvent::VERSION;
		1329
		1330	sub io($$$) {
		1331	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1332	}
		1333
		1334	sub timer($$$) {
		1335	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1336	}
		1337
		1338	sub signal($$) {
		1339	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1340	}
		1341
		1342	sub child($$) {
		1343	AnyEvent->child (pid => $_[0], cb => $_[1])
		1344	}
		1345
		1346	sub idle($) {
		1347	AnyEvent->idle (cb => $_[0])
		1348	}
		1349
		1350	sub cv(;&) {
		1351	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1352	}
		1353
		1354	sub now() {
		1355	AnyEvent->now
		1356	}
		1357
		1358	sub now_update() {
		1359	AnyEvent->now_update
		1360	}
		1361
		1362	sub time() {
		1363	AnyEvent->time
		1364	}
		1365
1096	package AnyEvent::Base;	1366	package AnyEvent::Base;
1097		1367
1098	# default implementations for many methods	1368	# default implementations for many methods
1099		1369
1100	BEGIN {	1370	sub _time() {
		1371	# probe for availability of Time::HiRes
1101	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1372	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1373	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1102	*_time = \&Time::HiRes::time;	1374	*_time = \&Time::HiRes::time;
1103	# if (eval "use POSIX (); (POSIX::times())...	1375	# if (eval "use POSIX (); (POSIX::times())...
1104	} else {	1376	} else {
		1377	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1105	*_time = sub { time }; # epic fail	1378	*_time = sub { time }; # epic fail
1106	}	1379	}
		1380
		1381	&_time
1107	}	1382	}
1108		1383
1109	sub time { _time }	1384	sub time { _time }
1110	sub now { _time }	1385	sub now { _time }
1111	sub now_update { }	1386	sub now_update { }
…		…
1116	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1391	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1117	}	1392	}
1118		1393
1119	# default implementation for ->signal	1394	# default implementation for ->signal
1120		1395
		1396	our $HAVE_ASYNC_INTERRUPT;
		1397
		1398	sub _have_async_interrupt() {
		1399	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1400	&& eval "use Async::Interrupt 1.02 (); 1")
		1401	unless defined $HAVE_ASYNC_INTERRUPT;
		1402
		1403	$HAVE_ASYNC_INTERRUPT
		1404	}
		1405
1121	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1406	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1407	our (%SIG_ASY, %SIG_ASY_W);
		1408	our ($SIG_COUNT, $SIG_TW);
1122		1409
1123	sub _signal_exec {	1410	sub _signal_exec {
		1411	$HAVE_ASYNC_INTERRUPT
		1412	? $SIGPIPE_R->drain
1124	sysread $SIGPIPE_R, my $dummy, 4;	1413	: sysread $SIGPIPE_R, (my $dummy), 9;
1125		1414
1126	while (%SIG_EV) {	1415	while (%SIG_EV) {
1127	for (keys %SIG_EV) {	1416	for (keys %SIG_EV) {
1128	delete $SIG_EV{$_};	1417	delete $SIG_EV{$_};
1129	$_->() for values %{ $SIG_CB{$_} || {} };	1418	$_->() for values %{ $SIG_CB{$_} || {} };
1130	}	1419	}
1131	}	1420	}
1132	}	1421	}
1133		1422
		1423	# install a dummy wakeup watcher to reduce signal catching latency
		1424	sub _sig_add() {
		1425	unless ($SIG_COUNT++) {
		1426	# try to align timer on a full-second boundary, if possible
		1427	my $NOW = AE::now;
		1428
		1429	$SIG_TW = AE::timer
		1430	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1431	$MAX_SIGNAL_LATENCY,
		1432	sub { } # just for the PERL_ASYNC_CHECK
		1433	;
		1434	}
		1435	}
		1436
		1437	sub _sig_del {
		1438	undef $SIG_TW
		1439	unless --$SIG_COUNT;
		1440	}
		1441
		1442	our $_sig_name_init; $_sig_name_init = sub {
		1443	eval q{ # poor man's autoloading
		1444	undef $_sig_name_init;
		1445
		1446	if (_have_async_interrupt) {
		1447	*sig2num = \&Async::Interrupt::sig2num;
		1448	*sig2name = \&Async::Interrupt::sig2name;
		1449	} else {
		1450	require Config;
		1451
		1452	my %signame2num;
		1453	@signame2num{ split ' ', $Config::Config{sig_name} }
		1454	= split ' ', $Config::Config{sig_num};
		1455
		1456	my @signum2name;
		1457	@signum2name[values %signame2num] = keys %signame2num;
		1458
		1459	*sig2num = sub($) {
		1460	$_[0] > 0 ? shift : $signame2num{+shift}
		1461	};
		1462	*sig2name = sub ($) {
		1463	$_[0] > 0 ? $signum2name[+shift] : shift
		1464	};
		1465	}
		1466	};
		1467	die if $@;
		1468	};
		1469
		1470	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1471	sub sig2name($) { &$_sig_name_init; &sig2name }
		1472
1134	sub signal {	1473	sub signal {
1135	my (undef, %arg) = @_;	1474	eval q{ # poor man's autoloading {}
		1475	# probe for availability of Async::Interrupt
		1476	if (_have_async_interrupt) {
		1477	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1136		1478
1137	unless ($SIGPIPE_R) {	1479	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1138	require Fcntl;	1480	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1139		1481
1140	if (AnyEvent::WIN32) {
1141	require AnyEvent::Util;
1142
1143	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1144	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1145	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1146	} else {	1482	} else {
		1483	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1484
		1485	require Fcntl;
		1486
		1487	if (AnyEvent::WIN32) {
		1488	require AnyEvent::Util;
		1489
		1490	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1491	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1492	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1493	} else {
1147	pipe $SIGPIPE_R, $SIGPIPE_W;	1494	pipe $SIGPIPE_R, $SIGPIPE_W;
1148	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1495	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1149	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1496	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1150		1497
1151	# not strictly required, as $^F is normally 2, but let's make sure...	1498	# not strictly required, as $^F is normally 2, but let's make sure...
1152	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1499	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1153	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1500	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1501	}
		1502
		1503	$SIGPIPE_R
		1504	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1505
		1506	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1154	}	1507	}
1155		1508
1156	$SIGPIPE_R	1509	*signal = sub {
1157	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1510	my (undef, %arg) = @_;
1158		1511
1159	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1160	}
1161
1162	my $signal = uc $arg{signal}	1512	my $signal = uc $arg{signal}
1163	or Carp::croak "required option 'signal' is missing";	1513	or Carp::croak "required option 'signal' is missing";
1164		1514
		1515	if ($HAVE_ASYNC_INTERRUPT) {
		1516	# async::interrupt
		1517
		1518	$signal = sig2num $signal;
1165	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1519	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1520
		1521	$SIG_ASY{$signal} ||= new Async::Interrupt
		1522	cb => sub { undef $SIG_EV{$signal} },
		1523	signal => $signal,
		1524	pipe => [$SIGPIPE_R->filenos],
		1525	pipe_autodrain => 0,
		1526	;
		1527
		1528	} else {
		1529	# pure perl
		1530
		1531	# AE::Util has been loaded in signal
		1532	$signal = sig2name $signal;
		1533	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1534
1166	$SIG{$signal} ||= sub {	1535	$SIG{$signal} ||= sub {
1167	local $!;	1536	local $!;
1168	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1537	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1169	undef $SIG_EV{$signal};	1538	undef $SIG_EV{$signal};
		1539	};
		1540
		1541	# can't do signal processing without introducing races in pure perl,
		1542	# so limit the signal latency.
		1543	_sig_add;
		1544	}
		1545
		1546	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1547	};
		1548
		1549	*AnyEvent::Base::signal::DESTROY = sub {
		1550	my ($signal, $cb) = @{$_[0]};
		1551
		1552	_sig_del;
		1553
		1554	delete $SIG_CB{$signal}{$cb};
		1555
		1556	$HAVE_ASYNC_INTERRUPT
		1557	? delete $SIG_ASY{$signal}
		1558	: # delete doesn't work with older perls - they then
		1559	# print weird messages, or just unconditionally exit
		1560	# instead of getting the default action.
		1561	undef $SIG{$signal}
		1562	unless keys %{ $SIG_CB{$signal} };
		1563	};
1170	};	1564	};
1171		1565	die if $@;
1172	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1566	&signal
1173	}
1174
1175	sub AnyEvent::Base::signal::DESTROY {
1176	my ($signal, $cb) = @{$_[0]};
1177
1178	delete $SIG_CB{$signal}{$cb};
1179
1180	# delete doesn't work with older perls - they then
1181	# print weird messages, or just unconditionally exit
1182	# instead of getting the default action.
1183	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1184	}	1567	}
1185		1568
1186	# default implementation for ->child	1569	# default implementation for ->child
1187		1570
1188	our %PID_CB;	1571	our %PID_CB;
1189	our $CHLD_W;	1572	our $CHLD_W;
1190	our $CHLD_DELAY_W;	1573	our $CHLD_DELAY_W;
1191	our $WNOHANG;	1574	our $WNOHANG;
1192		1575
		1576	sub _emit_childstatus($$) {
		1577	my (undef, $rpid, $rstatus) = @_;
		1578
		1579	$_->($rpid, $rstatus)
		1580	for values %{ $PID_CB{$rpid} || {} },
		1581	values %{ $PID_CB{0} || {} };
		1582	}
		1583
1193	sub _sigchld {	1584	sub _sigchld {
		1585	my $pid;
		1586
		1587	AnyEvent->_emit_childstatus ($pid, $?)
1194	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1588	while ($pid = waitpid -1, $WNOHANG) > 0;
1195	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),
1196	(values %{ $PID_CB{0} || {} });
1197	}
1198	}	1589	}
1199		1590
1200	sub child {	1591	sub child {
1201	my (undef, %arg) = @_;	1592	my (undef, %arg) = @_;
1202		1593
1203	defined (my $pid = $arg{pid} + 0)	1594	defined (my $pid = $arg{pid} + 0)
1204	or Carp::croak "required option 'pid' is missing";	1595	or Carp::croak "required option 'pid' is missing";
1205		1596
1206	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1597	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1207		1598
		1599	# WNOHANG is almost cetrainly 1 everywhere
		1600	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1601	? 1
1208	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1602	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1209		1603
1210	unless ($CHLD_W) {	1604	unless ($CHLD_W) {
1211	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1605	$CHLD_W = AE::signal CHLD => \&_sigchld;
1212	# child could be a zombie already, so make at least one round	1606	# child could be a zombie already, so make at least one round
1213	&_sigchld;	1607	&_sigchld;
1214	}	1608	}
1215		1609
1216	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1610	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
…		…
1242	# never use more then 50% of the time for the idle watcher,	1636	# never use more then 50% of the time for the idle watcher,
1243	# within some limits	1637	# within some limits
1244	$w = 0.0001 if $w < 0.0001;	1638	$w = 0.0001 if $w < 0.0001;
1245	$w = 5 if $w > 5;	1639	$w = 5 if $w > 5;
1246		1640
1247	$w = AnyEvent->timer (after => $w, cb => $rcb);	1641	$w = AE::timer $w, 0, $rcb;
1248	} else {	1642	} else {
1249	# clean up...	1643	# clean up...
1250	undef $w;	1644	undef $w;
1251	undef $rcb;	1645	undef $rcb;
1252	}	1646	}
1253	};	1647	};
1254		1648
1255	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1649	$w = AE::timer 0.05, 0, $rcb;
1256		1650
1257	bless \\$cb, "AnyEvent::Base::idle"	1651	bless \\$cb, "AnyEvent::Base::idle"
1258	}	1652	}
1259		1653
1260	sub AnyEvent::Base::idle::DESTROY {	1654	sub AnyEvent::Base::idle::DESTROY {
…		…
1265		1659
1266	our @ISA = AnyEvent::CondVar::Base::;	1660	our @ISA = AnyEvent::CondVar::Base::;
1267		1661
1268	package AnyEvent::CondVar::Base;	1662	package AnyEvent::CondVar::Base;
1269		1663
1270	use overload	1664	#use overload
1271	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1665	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1272	fallback => 1;	1666	# fallback => 1;
		1667
		1668	# save 300+ kilobytes by dirtily hardcoding overloading
		1669	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1670	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1671	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1672	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1673
		1674	our $WAITING;
1273		1675
1274	sub _send {	1676	sub _send {
1275	# nop	1677	# nop
1276	}	1678	}
1277		1679
…		…
1290	sub ready {	1692	sub ready {
1291	$_[0]{_ae_sent}	1693	$_[0]{_ae_sent}
1292	}	1694	}
1293		1695
1294	sub _wait {	1696	sub _wait {
		1697	$WAITING
		1698	and !$_[0]{_ae_sent}
		1699	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1700
		1701	local $WAITING = 1;
1295	AnyEvent->one_event while !$_[0]{_ae_sent};	1702	AnyEvent->one_event while !$_[0]{_ae_sent};
1296	}	1703	}
1297		1704
1298	sub recv {	1705	sub recv {
1299	$_[0]->_wait;	1706	$_[0]->_wait;
…		…
1301	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1708	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1302	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1709	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1303	}	1710	}
1304		1711
1305	sub cb {	1712	sub cb {
1306	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1713	my $cv = shift;
		1714
		1715	@_
		1716	and $cv->{_ae_cb} = shift
		1717	and $cv->{_ae_sent}
		1718	and (delete $cv->{_ae_cb})->($cv);
		1719
1307	$_[0]{_ae_cb}	1720	$cv->{_ae_cb}
1308	}	1721	}
1309		1722
1310	sub begin {	1723	sub begin {
1311	++$_[0]{_ae_counter};	1724	++$_[0]{_ae_counter};
1312	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1725	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1361	C<PERL_ANYEVENT_MODEL>.	1774	C<PERL_ANYEVENT_MODEL>.
1362		1775
1363	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1776	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1364	model it chooses.	1777	model it chooses.
1365		1778
		1779	When set to C<8> or higher, then AnyEvent will report extra information on
		1780	which optional modules it loads and how it implements certain features.
		1781
1366	=item C<PERL_ANYEVENT_STRICT>	1782	=item C<PERL_ANYEVENT_STRICT>
1367		1783
1368	AnyEvent does not do much argument checking by default, as thorough	1784	AnyEvent does not do much argument checking by default, as thorough
1369	argument checking is very costly. Setting this variable to a true value	1785	argument checking is very costly. Setting this variable to a true value
1370	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1786	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1371	check the arguments passed to most method calls. If it finds any problems	1787	check the arguments passed to most method calls. If it finds any problems,
1372	it will croak.	1788	it will croak.
1373		1789
1374	In other words, enables "strict" mode.	1790	In other words, enables "strict" mode.
1375		1791
1376	Unlike C<use strict>, it is definitely recommended ot keep it off in	1792	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1377	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1793	>>, it is definitely recommended to keep it off in production. Keeping
1378	developing programs can be very useful, however.	1794	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1795	can be very useful, however.
1379		1796
1380	=item C<PERL_ANYEVENT_MODEL>	1797	=item C<PERL_ANYEVENT_MODEL>
1381		1798
1382	This can be used to specify the event model to be used by AnyEvent, before	1799	This can be used to specify the event model to be used by AnyEvent, before
1383	auto detection and -probing kicks in. It must be a string consisting	1800	auto detection and -probing kicks in. It must be a string consisting
…		…
1426		1843
1427	=item C<PERL_ANYEVENT_MAX_FORKS>	1844	=item C<PERL_ANYEVENT_MAX_FORKS>
1428		1845
1429	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1846	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1430	will create in parallel.	1847	will create in parallel.
		1848
		1849	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1850
		1851	The default value for the C<max_outstanding> parameter for the default DNS
		1852	resolver - this is the maximum number of parallel DNS requests that are
		1853	sent to the DNS server.
		1854
		1855	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1856
		1857	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1858	configuration) in the default resolver. When set to the empty string, no
		1859	default config will be used.
		1860
		1861	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1862
		1863	When neither C<ca_file> nor C<ca_path> was specified during
		1864	L<AnyEvent::TLS> context creation, and either of these environment
		1865	variables exist, they will be used to specify CA certificate locations
		1866	instead of a system-dependent default.
		1867
		1868	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1869
		1870	When these are set to C<1>, then the respective modules are not
		1871	loaded. Mostly good for testing AnyEvent itself.
1431		1872
1432	=back	1873	=back
1433		1874
1434	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1875	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1435		1876
…		…
1493	warn "read: $input\n"; # output what has been read	1934	warn "read: $input\n"; # output what has been read
1494	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1935	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1495	},	1936	},
1496	);	1937	);
1497		1938
1498	my $time_watcher; # can only be used once
1499
1500	sub new_timer {
1501	$timer = AnyEvent->timer (after => 1, cb => sub {	1939	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1502	warn "timeout\n"; # print 'timeout' about every second	1940	warn "timeout\n"; # print 'timeout' at most every second
1503	&new_timer; # and restart the time
1504	});	1941	});
1505	}
1506
1507	new_timer; # create first timer
1508		1942
1509	$cv->recv; # wait until user enters /^q/i	1943	$cv->recv; # wait until user enters /^q/i
1510		1944
1511	=head1 REAL-WORLD EXAMPLE	1945	=head1 REAL-WORLD EXAMPLE
1512		1946
…		…
1643	through AnyEvent. The benchmark creates a lot of timers (with a zero	2077	through AnyEvent. The benchmark creates a lot of timers (with a zero
1644	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2078	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1645	which it is), lets them fire exactly once and destroys them again.	2079	which it is), lets them fire exactly once and destroys them again.
1646		2080
1647	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2081	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1648	distribution.	2082	distribution. It uses the L<AE> interface, which makes a real difference
		2083	for the EV and Perl backends only.
1649		2084
1650	=head3 Explanation of the columns	2085	=head3 Explanation of the columns
1651		2086
1652	I<watcher> is the number of event watchers created/destroyed. Since	2087	I<watcher> is the number of event watchers created/destroyed. Since
1653	different event models feature vastly different performances, each event	2088	different event models feature vastly different performances, each event
…		…
1674	watcher.	2109	watcher.
1675		2110
1676	=head3 Results	2111	=head3 Results
1677		2112
1678	name watchers bytes create invoke destroy comment	2113	name watchers bytes create invoke destroy comment
1679	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2114	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1680	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2115	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1681	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2116	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1682	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2117	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1683	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2118	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1684	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2119	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2120	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2121	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1685	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2122	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1686	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2123	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1687	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2124	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1688	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2125	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1689		2126
1690	=head3 Discussion	2127	=head3 Discussion
1691		2128
1692	The benchmark does I<not> measure scalability of the event loop very	2129	The benchmark does I<not> measure scalability of the event loop very
1693	well. For example, a select-based event loop (such as the pure perl one)	2130	well. For example, a select-based event loop (such as the pure perl one)
…		…
1705	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2142	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1706	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2143	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1707	cycles with POE.	2144	cycles with POE.
1708		2145
1709	C<EV> is the sole leader regarding speed and memory use, which are both	2146	C<EV> is the sole leader regarding speed and memory use, which are both
1710	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2147	maximal/minimal, respectively. When using the L<AE> API there is zero
		2148	overhead (when going through the AnyEvent API create is about 5-6 times
		2149	slower, with other times being equal, so still uses far less memory than
1711	far less memory than any other event loop and is still faster than Event	2150	any other event loop and is still faster than Event natively).
1712	natively.
1713		2151
1714	The pure perl implementation is hit in a few sweet spots (both the	2152	The pure perl implementation is hit in a few sweet spots (both the
1715	constant timeout and the use of a single fd hit optimisations in the perl	2153	constant timeout and the use of a single fd hit optimisations in the perl
1716	interpreter and the backend itself). Nevertheless this shows that it	2154	interpreter and the backend itself). Nevertheless this shows that it
1717	adds very little overhead in itself. Like any select-based backend its	2155	adds very little overhead in itself. Like any select-based backend its
1718	performance becomes really bad with lots of file descriptors (and few of	2156	performance becomes really bad with lots of file descriptors (and few of
1719	them active), of course, but this was not subject of this benchmark.	2157	them active), of course, but this was not subject of this benchmark.
1720		2158
1721	The C<Event> module has a relatively high setup and callback invocation	2159	The C<Event> module has a relatively high setup and callback invocation
1722	cost, but overall scores in on the third place.	2160	cost, but overall scores in on the third place.
		2161
		2162	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2163	when using its pure perl backend.
1723		2164
1724	C<Glib>'s memory usage is quite a bit higher, but it features a	2165	C<Glib>'s memory usage is quite a bit higher, but it features a
1725	faster callback invocation and overall ends up in the same class as	2166	faster callback invocation and overall ends up in the same class as
1726	C<Event>. However, Glib scales extremely badly, doubling the number of	2167	C<Event>. However, Glib scales extremely badly, doubling the number of
1727	watchers increases the processing time by more than a factor of four,	2168	watchers increases the processing time by more than a factor of four,
…		…
1788	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2229	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1789	(1%) are active. This mirrors the activity of large servers with many	2230	(1%) are active. This mirrors the activity of large servers with many
1790	connections, most of which are idle at any one point in time.	2231	connections, most of which are idle at any one point in time.
1791		2232
1792	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2233	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1793	distribution.	2234	distribution. It uses the L<AE> interface, which makes a real difference
		2235	for the EV and Perl backends only.
1794		2236
1795	=head3 Explanation of the columns	2237	=head3 Explanation of the columns
1796		2238
1797	I<sockets> is the number of sockets, and twice the number of "servers" (as	2239	I<sockets> is the number of sockets, and twice the number of "servers" (as
1798	each server has a read and write socket end).	2240	each server has a read and write socket end).
…		…
1805	it to another server. This includes deleting the old timeout and creating	2247	it to another server. This includes deleting the old timeout and creating
1806	a new one that moves the timeout into the future.	2248	a new one that moves the timeout into the future.
1807		2249
1808	=head3 Results	2250	=head3 Results
1809		2251
1810	name sockets create request	2252	name sockets create request
1811	EV 20000 69.01 11.16	2253	EV 20000 62.66 7.99
1812	Perl 20000 73.32 35.87	2254	Perl 20000 68.32 32.64
1813	Event 20000 212.62 257.32	2255	IOAsync 20000 174.06 101.15 epoll
1814	Glib 20000 651.16 1896.30	2256	IOAsync 20000 174.67 610.84 poll
		2257	Event 20000 202.69 242.91
		2258	Glib 20000 557.01 1689.52
1815	POE 20000 349.67 12317.24 uses POE::Loop::Event	2259	POE 20000 341.54 12086.32 uses POE::Loop::Event
1816		2260
1817	=head3 Discussion	2261	=head3 Discussion
1818		2262
1819	This benchmark I<does> measure scalability and overall performance of the	2263	This benchmark I<does> measure scalability and overall performance of the
1820	particular event loop.	2264	particular event loop.
…		…
1822	EV is again fastest. Since it is using epoll on my system, the setup time	2266	EV is again fastest. Since it is using epoll on my system, the setup time
1823	is relatively high, though.	2267	is relatively high, though.
1824		2268
1825	Perl surprisingly comes second. It is much faster than the C-based event	2269	Perl surprisingly comes second. It is much faster than the C-based event
1826	loops Event and Glib.	2270	loops Event and Glib.
		2271
		2272	IO::Async performs very well when using its epoll backend, and still quite
		2273	good compared to Glib when using its pure perl backend.
1827		2274
1828	Event suffers from high setup time as well (look at its code and you will	2275	Event suffers from high setup time as well (look at its code and you will
1829	understand why). Callback invocation also has a high overhead compared to	2276	understand why). Callback invocation also has a high overhead compared to
1830	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2277	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1831	uses select or poll in basically all documented configurations.	2278	uses select or poll in basically all documented configurations.
…		…
1900		2347
1901	Recently I was told about the benchmark in the IO::Lambda manpage, which	2348	Recently I was told about the benchmark in the IO::Lambda manpage, which
1902	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark	2349	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
1903	simply compares IO::Lambda with POE, and IO::Lambda looks better (which	2350	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
1904	shouldn't come as a surprise to anybody). As such, the benchmark is	2351	shouldn't come as a surprise to anybody). As such, the benchmark is
1905	fine, and shows that the AnyEvent backend from IO::Lambda isn't very	2352	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
1906	optimal. But how would AnyEvent compare when used without the extra	2353	very optimal. But how would AnyEvent compare when used without the extra
1907	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.	2354	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
1908		2355
1909	The benchmark itself creates an echo-server, and then, for 500 times,	2356	The benchmark itself creates an echo-server, and then, for 500 times,
1910	connects to the echo server, sends a line, waits for the reply, and then	2357	connects to the echo server, sends a line, waits for the reply, and then
1911	creates the next connection. This is a rather bad benchmark, as it doesn't	2358	creates the next connection. This is a rather bad benchmark, as it doesn't
1912	test the efficiency of the framework, but it is a benchmark nevertheless.	2359	test the efficiency of the framework or much non-blocking I/O, but it is a
		2360	benchmark nevertheless.
1913		2361
1914	name runtime	2362	name runtime
1915	Lambda/select 0.330 sec	2363	Lambda/select 0.330 sec
1916	+ optimized 0.122 sec	2364	+ optimized 0.122 sec
1917	Lambda/AnyEvent 0.327 sec	2365	Lambda/AnyEvent 0.327 sec
…		…
1923		2371
1924	AnyEvent/select/nb 0.085 sec	2372	AnyEvent/select/nb 0.085 sec
1925	AnyEvent/EV/nb 0.068 sec	2373	AnyEvent/EV/nb 0.068 sec
1926	+state machine 0.134 sec	2374	+state machine 0.134 sec
1927		2375
1928	The benchmark is also a bit unfair (my fault) - the IO::Lambda	2376	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
1929	benchmarks actually make blocking connects and use 100% blocking I/O,	2377	benchmarks actually make blocking connects and use 100% blocking I/O,
1930	defeating the purpose of an event-based solution. All of the newly	2378	defeating the purpose of an event-based solution. All of the newly
1931	written AnyEvent benchmarks use 100% non-blocking connects (using	2379	written AnyEvent benchmarks use 100% non-blocking connects (using
1932	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS	2380	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
1933	resolver), so AnyEvent is at a disadvantage here as non-blocking connects	2381	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
1934	generally require a lot more bookkeeping and event handling than blocking	2382	generally require a lot more bookkeeping and event handling than blocking
1935	connects (which involve a single syscall only).	2383	connects (which involve a single syscall only).
1936		2384
1937	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which	2385	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
1938	offers similar expressive power as POE and IO::Lambda (using conventional	2386	offers similar expressive power as POE and IO::Lambda, using conventional
1939	Perl syntax), which means both the echo server and the client are 100%	2387	Perl syntax. This means that both the echo server and the client are 100%
1940	non-blocking w.r.t. I/O, further placing it at a disadvantage.	2388	non-blocking, further placing it at a disadvantage.
1941		2389
1942	As you can see, AnyEvent + EV even beats the hand-optimised "raw sockets	2390	As you can see, the AnyEvent + EV combination even beats the
1943	benchmark", while AnyEvent + its pure perl backend easily beats	2391	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
1944	IO::Lambda and POE.	2392	backend easily beats IO::Lambda and POE.
1945		2393
1946	And even the 100% non-blocking version written using the high-level (and	2394	And even the 100% non-blocking version written using the high-level (and
1947	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda,	2395	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2396	higher level ("unoptimised") abstractions by a large margin, even though
1948	even thought it does all of DNS, tcp-connect and socket I/O in a	2397	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
1949	non-blocking way.	2398
		2399	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2400	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2401	part of the IO::Lambda distribution and were used without any changes.
1950		2402
1951		2403
1952	=head1 SIGNALS	2404	=head1 SIGNALS
1953		2405
1954	AnyEvent currently installs handlers for these signals:	2406	AnyEvent currently installs handlers for these signals:
…		…
1958	=item SIGCHLD	2410	=item SIGCHLD
1959		2411
1960	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2412	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1961	emulation for event loops that do not support them natively. Also, some	2413	emulation for event loops that do not support them natively. Also, some
1962	event loops install a similar handler.	2414	event loops install a similar handler.
		2415
		2416	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2417	AnyEvent will reset it to default, to avoid losing child exit statuses.
1963		2418
1964	=item SIGPIPE	2419	=item SIGPIPE
1965		2420
1966	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2421	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1967	when AnyEvent gets loaded.	2422	when AnyEvent gets loaded.
…		…
1979		2434
1980	=back	2435	=back
1981		2436
1982	=cut	2437	=cut
1983		2438
		2439	undef $SIG{CHLD}
		2440	if $SIG{CHLD} eq 'IGNORE';
		2441
1984	$SIG{PIPE} = sub { }	2442	$SIG{PIPE} = sub { }
1985	unless defined $SIG{PIPE};	2443	unless defined $SIG{PIPE};
		2444
		2445	=head1 RECOMMENDED/OPTIONAL MODULES
		2446
		2447	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2448	it's built-in modules) are required to use it.
		2449
		2450	That does not mean that AnyEvent won't take advantage of some additional
		2451	modules if they are installed.
		2452
		2453	This section explains which additional modules will be used, and how they
		2454	affect AnyEvent's operation.
		2455
		2456	=over 4
		2457
		2458	=item L<Async::Interrupt>
		2459
		2460	This slightly arcane module is used to implement fast signal handling: To
		2461	my knowledge, there is no way to do completely race-free and quick
		2462	signal handling in pure perl. To ensure that signals still get
		2463	delivered, AnyEvent will start an interval timer to wake up perl (and
		2464	catch the signals) with some delay (default is 10 seconds, look for
		2465	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2466
		2467	If this module is available, then it will be used to implement signal
		2468	catching, which means that signals will not be delayed, and the event loop
		2469	will not be interrupted regularly, which is more efficient (and good for
		2470	battery life on laptops).
		2471
		2472	This affects not just the pure-perl event loop, but also other event loops
		2473	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2474
		2475	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2476	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2477	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2478	does nothing for those backends.
		2479
		2480	=item L<EV>
		2481
		2482	This module isn't really "optional", as it is simply one of the backend
		2483	event loops that AnyEvent can use. However, it is simply the best event
		2484	loop available in terms of features, speed and stability: It supports
		2485	the AnyEvent API optimally, implements all the watcher types in XS, does
		2486	automatic timer adjustments even when no monotonic clock is available,
		2487	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2488	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2489	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2490
		2491	=item L<Guard>
		2492
		2493	The guard module, when used, will be used to implement
		2494	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2495	lot less memory), but otherwise doesn't affect guard operation much. It is
		2496	purely used for performance.
		2497
		2498	=item L<JSON> and L<JSON::XS>
		2499
		2500	One of these modules is required when you want to read or write JSON data
		2501	via L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2502	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2503
		2504	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2505	installed.
		2506
		2507	=item L<Net::SSLeay>
		2508
		2509	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2510	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2511	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2512
		2513	=item L<Time::HiRes>
		2514
		2515	This module is part of perl since release 5.008. It will be used when the
		2516	chosen event library does not come with a timing source on it's own. The
		2517	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2518	try to use a monotonic clock for timing stability.
		2519
		2520	=back
1986		2521
1987		2522
1988	=head1 FORK	2523	=head1 FORK
1989		2524
1990	Most event libraries are not fork-safe. The ones who are usually are	2525	Most event libraries are not fork-safe. The ones who are usually are
1991	because they rely on inefficient but fork-safe C<select> or C<poll>	2526	because they rely on inefficient but fork-safe C<select> or C<poll>
1992	calls. Only L<EV> is fully fork-aware.	2527	calls. Only L<EV> is fully fork-aware.
1993		2528
		2529	This means that, in general, you cannot fork and do event processing
		2530	in the child if a watcher was created before the fork (which in turn
		2531	initialises the event library).
		2532
1994	If you have to fork, you must either do so I<before> creating your first	2533	If you have to fork, you must either do so I<before> creating your first
1995	watcher OR you must not use AnyEvent at all in the child.	2534	watcher OR you must not use AnyEvent at all in the child OR you must do
		2535	something completely out of the scope of AnyEvent.
		2536
		2537	The problem of doing event processing in the parent I<and> the child
		2538	is much more complicated: even for backends that I<are> fork-aware or
		2539	fork-safe, their behaviour is not usually what you want: fork clones all
		2540	watchers, that means all timers, I/O watchers etc. are active in both
		2541	parent and child, which is almost never what you want.
1996		2542
1997		2543
1998	=head1 SECURITY CONSIDERATIONS	2544	=head1 SECURITY CONSIDERATIONS
1999		2545
2000	AnyEvent can be forced to load any event model via	2546	AnyEvent can be forced to load any event model via
…		…
2014	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2560	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
2015	be used to probe what backend is used and gain other information (which is	2561	be used to probe what backend is used and gain other information (which is
2016	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2562	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
2017	$ENV{PERL_ANYEVENT_STRICT}.	2563	$ENV{PERL_ANYEVENT_STRICT}.
2018		2564
		2565	Note that AnyEvent will remove I<all> environment variables starting with
		2566	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2567	enabled.
		2568
2019		2569
2020	=head1 BUGS	2570	=head1 BUGS
2021		2571
2022	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2572	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
2023	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2573	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
…		…
2034	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2584	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2035		2585
2036	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2586	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2037	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2587	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2038	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2588	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2039	L<AnyEvent::Impl::POE>.	2589	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2040		2590
2041	Non-blocking file handles, sockets, TCP clients and	2591	Non-blocking file handles, sockets, TCP clients and
2042	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2592	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2043		2593
2044	Asynchronous DNS: L<AnyEvent::DNS>.	2594	Asynchronous DNS: L<AnyEvent::DNS>.
2045		2595
2046	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2596	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2597	L<Coro::Event>,
2047		2598
2048	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2599	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2600	L<AnyEvent::HTTP>.
2049		2601
2050		2602
2051	=head1 AUTHOR	2603	=head1 AUTHOR
2052		2604
2053	Marc Lehmann <schmorp@schmorp.de>	2605	Marc Lehmann <schmorp@schmorp.de>

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