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Revision 1.306 by root, Tue Dec 15 05:49:13 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
…		…
403		476
404	This means you cannot create a child watcher as the very first	477	This means you cannot create a child watcher as the very first
405	thing in an AnyEvent program, you I<have> to create at least one	478	thing in an AnyEvent program, you I<have> to create at least one
406	watcher before you C<fork> the child (alternatively, you can call	479	watcher before you C<fork> the child (alternatively, you can call
407	C<AnyEvent::detect>).	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.
408		485
409	Example: fork a process and wait for it	486	Example: fork a process and wait for it
410		487
411	my $done = AnyEvent->condvar;	488	my $done = AnyEvent->condvar;
412		489
…		…
424	# do something else, then wait for process exit	501	# do something else, then wait for process exit
425	$done->recv;	502	$done->recv;
426		503
427	=head2 IDLE WATCHERS	504	=head2 IDLE WATCHERS
428		505
		506	$w = AnyEvent->idle (cb => <callback>);
		507
429	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
430	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
431	"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
432	attention by the event loop".	511	attention by the event loop".
433		512
…		…
459	});	538	});
460	});	539	});
461		540
462	=head2 CONDITION VARIABLES	541	=head2 CONDITION VARIABLES
463		542
		543	$cv = AnyEvent->condvar;
		544
		545	$cv->send (<list>);
		546	my @res = $cv->recv;
		547
464	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
465	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
466	will actively watch for new events and call your callbacks.	550	will actively watch for new events and call your callbacks.
467		551
468	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
469	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).
470		554
471	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
472	because they represent a condition that must become true.	556	because they represent a condition that must become true.
473		557
		558	Now is probably a good time to look at the examples further below.
		559
474	Condition variables can be created by calling the C<< AnyEvent->condvar	560	Condition variables can be created by calling the C<< AnyEvent->condvar
475	>> method, usually without arguments. The only argument pair allowed is	561	>> method, usually without arguments. The only argument pair allowed is
476
477	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
478	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
479	the results).	564	the results).
480		565
481	After creation, the condition variable is "false" until it becomes "true"	566	After creation, the condition variable is "false" until it becomes "true"
…		…
486	Condition variables are similar to callbacks, except that you can	571	Condition variables are similar to callbacks, except that you can
487	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
488	in time where multiple outstanding events have been processed. And yet	573	in time where multiple outstanding events have been processed. And yet
489	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
490	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
491	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.
492		578
493	Condition variables are very useful to signal that something has finished,	579	Condition variables are very useful to signal that something has finished,
494	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,
495	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
496	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
…		…
530	after => 1,	616	after => 1,
531	cb => sub { $result_ready->send },	617	cb => sub { $result_ready->send },
532	);	618	);
533		619
534	# this "blocks" (while handling events) till the callback	620	# this "blocks" (while handling events) till the callback
535	# calls send	621	# calls ->send
536	$result_ready->recv;	622	$result_ready->recv;
537		623
538	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
539	condition variables are also code references.	625	variables are also callable directly.
540		626
541	my $done = AnyEvent->condvar;	627	my $done = AnyEvent->condvar;
542	my $delay = AnyEvent->timer (after => 5, cb => $done);	628	my $delay = AnyEvent->timer (after => 5, cb => $done);
543	$done->recv;	629	$done->recv;
544		630
…		…
550		636
551	...	637	...
552		638
553	my @info = $couchdb->info->recv;	639	my @info = $couchdb->info->recv;
554		640
555	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
556	results are available:	642	results are available:
557		643
558	$couchdb->info->cb (sub {	644	$couchdb->info->cb (sub {
559	my @info = $_[0]->recv;	645	my @info = $_[0]->recv;
560	});	646	});
…		…
578	immediately from within send.	664	immediately from within send.
579		665
580	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
581	future C<< ->recv >> calls.	667	future C<< ->recv >> calls.
582		668
583	Condition variables are overloaded so one can call them directly	669	Condition variables are overloaded so one can call them directly (as if
584	(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
585	C<send>. Note, however, that many C-based event loops do not handle	671	C<send>.
586	overloading, so as tempting as it may be, passing a condition variable
587	instead of a callback does not work. Both the pure perl and EV loops
588	support overloading, however, as well as all functions that use perl to
589	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
590	example).
591		672
592	=item $cv->croak ($error)	673	=item $cv->croak ($error)
593		674
594	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
595	C<Carp::croak> with the given error message/object/scalar.	676	C<Carp::croak> with the given error message/object/scalar.
596		677
597	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
598	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.
599		684
600	=item $cv->begin ([group callback])	685	=item $cv->begin ([group callback])
601		686
602	=item $cv->end	687	=item $cv->end
603
604	These two methods are EXPERIMENTAL and MIGHT CHANGE.
605		688
606	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
607	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
608	to use a condition variable for the whole process.	691	to use a condition variable for the whole process.
609		692
610	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
611	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
612	>>, 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
613	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
614	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.
615		699
616	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:
617		707
618	my $cv = AnyEvent->condvar;	708	my $cv = AnyEvent->condvar;
619		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
620	my %result;	734	my %result;
621	$cv->begin (sub { $cv->send (\%result) });	735	$cv->begin (sub { shift->send (\%result) });
622		736
623	for my $host (@list_of_hosts) {	737	for my $host (@list_of_hosts) {
624	$cv->begin;	738	$cv->begin;
625	ping_host_then_call_callback $host, sub {	739	ping_host_then_call_callback $host, sub {
626	$result{$host} = ...;	740	$result{$host} = ...;
…		…
641	loop, which serves two important purposes: first, it sets the callback	755	loop, which serves two important purposes: first, it sets the callback
642	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
643	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
644	doesn't execute once).	758	doesn't execute once).
645		759
646	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
647	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
648	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
649	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>.
650		765
651	=back	766	=back
652		767
653	=head3 METHODS FOR CONSUMERS	768	=head3 METHODS FOR CONSUMERS
654		769
…		…
670	function will call C<croak>.	785	function will call C<croak>.
671		786
672	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,
673	in scalar context only the first one will be returned.	788	in scalar context only the first one will be returned.
674		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
675	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
676	(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
677	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
678	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
679	condition variables with some kind of request results and supporting	801	condition variables with some kind of request results and supporting
680	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,
681	while still supporting blocking waits if the caller so desires).	803	while still supporting blocking waits if the caller so desires).
682		804
683	Another reason I<never> to C<< ->recv >> in a module is that you cannot
684	sensibly have two C<< ->recv >>'s in parallel, as that would require
685	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
686	can supply.
687
688	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
689	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
690	versions and also integrates coroutines into AnyEvent, making blocking
691	C<< ->recv >> calls perfectly safe as long as they are done from another
692	coroutine (one that doesn't run the event loop).
693
694	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
695	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
696	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
697	waits otherwise.	808	waits otherwise.
698		809
…		…
704	=item $cb = $cv->cb ($cb->($cv))	815	=item $cb = $cv->cb ($cb->($cv))
705		816
706	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
707	replaces it before doing so.	818	replaces it before doing so.
708		819
709	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)
710	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
711	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>
712	is guaranteed not to block.	823	inside the callback or at any later time is guaranteed not to block.
713		824
714	=back	825	=back
715		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
716	=head1 GLOBAL VARIABLES AND FUNCTIONS	895	=head1 GLOBAL VARIABLES AND FUNCTIONS
717		896
		897	These are not normally required to use AnyEvent, but can be useful to
		898	write AnyEvent extension modules.
		899
718	=over 4	900	=over 4
719		901
720	=item $AnyEvent::MODEL	902	=item $AnyEvent::MODEL
721		903
722	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
723	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
724	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
725	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
726	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
727		911	will be C<urxvt::anyevent>).
728	The known classes so far are:
729
730	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
731	AnyEvent::Impl::Event based on Event, second best choice.
732	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
733	AnyEvent::Impl::Glib based on Glib, third-best choice.
734	AnyEvent::Impl::Tk based on Tk, very bad choice.
735	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
736	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
737	AnyEvent::Impl::POE based on POE, not generic enough for full support.
738
739	# warning, support for IO::Async is only partial, as it is too broken
740	# and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
741	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
742
743	There is no support for WxWidgets, as WxWidgets has no support for
744	watching file handles. However, you can use WxWidgets through the
745	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
746	second, which was considered to be too horrible to even consider for
747	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
748	it's adaptor.
749
750	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
751	autodetecting them.
752		912
753	=item AnyEvent::detect	913	=item AnyEvent::detect
754		914
755	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	915	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
756	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
757	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
758	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>.
759		922
760	=item $guard = AnyEvent::post_detect { BLOCK }	923	=item $guard = AnyEvent::post_detect { BLOCK }
761		924
762	Arranges for the code block to be executed as soon as the event model is	925	Arranges for the code block to be executed as soon as the event model is
763	autodetected (or immediately if this has already happened).	926	autodetected (or immediately if this has already happened).
764		927
		928	The block will be executed I<after> the actual backend has been detected
		929	(C<$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
765	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
766	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
767	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 ||= $guard;
768		959
769	=item @AnyEvent::post_detect	960	=item @AnyEvent::post_detect
770		961
771	If there are any code references in this array (you can C<push> to it	962	If there are any code references in this array (you can C<push> to it
772	before or after loading AnyEvent), then they will called directly after	963	before or after loading AnyEvent), then they will called directly after
773	the event loop has been chosen.	964	the event loop has been chosen.
774		965
775	You should check C<$AnyEvent::MODEL> before adding to this array, though:	966	You should check C<$AnyEvent::MODEL> before adding to this array, though:
776	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
777	and the array will be ignored.	968	array will be ignored.
778		969
779	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.
		977
		978	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		979	together, you could put this into Coro (this is the actual code used by
		980	Coro to accomplish this):
		981
		982	if (defined $AnyEvent::MODEL) {
		983	# AnyEvent already initialised, so load Coro::AnyEvent
		984	require Coro::AnyEvent;
		985	} else {
		986	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		987	# as soon as it is
		988	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		989	}
780		990
781	=back	991	=back
782		992
783	=head1 WHAT TO DO IN A MODULE	993	=head1 WHAT TO DO IN A MODULE
784		994
…		…
839		1049
840		1050
841	=head1 OTHER MODULES	1051	=head1 OTHER MODULES
842		1052
843	The following is a non-exhaustive list of additional modules that use	1053	The following is a non-exhaustive list of additional modules that use
844	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1054	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
845	in the same program. Some of the modules come with AnyEvent, some are	1055	modules and other event loops in the same program. Some of the modules
846	available via CPAN.	1056	come with AnyEvent, most are available via CPAN.
847		1057
848	=over 4	1058	=over 4
849		1059
850	=item L<AnyEvent::Util>	1060	=item L<AnyEvent::Util>
851		1061
…		…
860		1070
861	=item L<AnyEvent::Handle>	1071	=item L<AnyEvent::Handle>
862		1072
863	Provide read and write buffers, manages watchers for reads and writes,	1073	Provide read and write buffers, manages watchers for reads and writes,
864	supports raw and formatted I/O, I/O queued and fully transparent and	1074	supports raw and formatted I/O, I/O queued and fully transparent and
865	non-blocking SSL/TLS.	1075	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
866		1076
867	=item L<AnyEvent::DNS>	1077	=item L<AnyEvent::DNS>
868		1078
869	Provides rich asynchronous DNS resolver capabilities.	1079	Provides rich asynchronous DNS resolver capabilities.
870		1080
…		…
898		1108
899	=item L<AnyEvent::GPSD>	1109	=item L<AnyEvent::GPSD>
900		1110
901	A non-blocking interface to gpsd, a daemon delivering GPS information.	1111	A non-blocking interface to gpsd, a daemon delivering GPS information.
902		1112
		1113	=item L<AnyEvent::IRC>
		1114
		1115	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1116
		1117	=item L<AnyEvent::XMPP>
		1118
		1119	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1120	Net::XMPP2>.
		1121
903	=item L<AnyEvent::IGS>	1122	=item L<AnyEvent::IGS>
904		1123
905	A non-blocking interface to the Internet Go Server protocol (used by	1124	A non-blocking interface to the Internet Go Server protocol (used by
906	L<App::IGS>).	1125	L<App::IGS>).
907		1126
908	=item L<AnyEvent::IRC>
909
910	AnyEvent based IRC client module family (replacing the older Net::IRC3).
911
912	=item L<Net::XMPP2>
913
914	AnyEvent based XMPP (Jabber protocol) module family.
915
916	=item L<Net::FCP>	1127	=item L<Net::FCP>
917		1128
918	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1129	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
919	of AnyEvent.	1130	of AnyEvent.
920		1131
…		…
924		1135
925	=item L<Coro>	1136	=item L<Coro>
926		1137
927	Has special support for AnyEvent via L<Coro::AnyEvent>.	1138	Has special support for AnyEvent via L<Coro::AnyEvent>.
928		1139
929	=item L<IO::Lambda>
930
931	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
932
933	=back	1140	=back
934		1141
935	=cut	1142	=cut
936		1143
937	package AnyEvent;	1144	package AnyEvent;
938		1145
939	no warnings;	1146	# basically a tuned-down version of common::sense
940	use strict qw(vars subs);	1147	sub common_sense {
		1148	# from common:.sense 1.0
		1149	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
		1150	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1151	$^H |= 0x00000600;
		1152	}
941		1153
		1154	BEGIN { AnyEvent::common_sense }
		1155
942	use Carp;	1156	use Carp ();
943		1157
944	our $VERSION = 4.412;	1158	our $VERSION = '5.22';
945	our $MODEL;	1159	our $MODEL;
946		1160
947	our $AUTOLOAD;	1161	our $AUTOLOAD;
948	our @ISA;	1162	our @ISA;
949		1163
950	our @REGISTRY;	1164	our @REGISTRY;
951		1165
952	our $WIN32;	1166	our $VERBOSE;
953		1167
954	BEGIN {	1168	BEGIN {
955	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1169	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
956	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1170	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
957		1171
958	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1172	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
959	if ${^TAINT};	1173	if ${^TAINT};
960	}
961		1174
962	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1175	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1176
		1177	}
		1178
		1179	our $MAX_SIGNAL_LATENCY = 10;
963		1180
964	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1181	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
965		1182
966	{	1183	{
967	my $idx;	1184	my $idx;
…		…
969	for reverse split /\s*,\s*/,	1186	for reverse split /\s*,\s*/,
970	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1187	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
971	}	1188	}
972		1189
973	my @models = (	1190	my @models = (
974	[EV:: => AnyEvent::Impl::EV::],	1191	[EV:: => AnyEvent::Impl::EV:: , 1],
975	[Event:: => AnyEvent::Impl::Event::],
976	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1192	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
977	# everything below here will not be autoprobed	1193	# everything below here will not (normally) be autoprobed
978	# as the pureperl backend should work everywhere	1194	# as the pureperl backend should work everywhere
979	# and is usually faster	1195	# and is usually faster
		1196	[Event:: => AnyEvent::Impl::Event::, 1],
		1197	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1198	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1199	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
980	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1200	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
981	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
982	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
983	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1201	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
984	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1202	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
985	[Wx:: => AnyEvent::Impl::POE::],	1203	[Wx:: => AnyEvent::Impl::POE::],
986	[Prima:: => AnyEvent::Impl::POE::],	1204	[Prima:: => AnyEvent::Impl::POE::],
987	# IO::Async is just too broken - we would need workaorunds for its	1205	# IO::Async is just too broken - we would need workarounds for its
988	# byzantine signal and broken child handling, among others.	1206	# byzantine signal and broken child handling, among others.
989	# IO::Async is rather hard to detect, as it doesn't have any	1207	# IO::Async is rather hard to detect, as it doesn't have any
990	# obvious default class.	1208	# obvious default class.
991	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program	1209	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
992	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program	1210	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
993	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program	1211	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1212	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
994	);	1213	);
995		1214
996	our %method = map +($_ => 1),	1215	our %method = map +($_ => 1),
997	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1216	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
998		1217
…		…
1002	my ($cb) = @_;	1221	my ($cb) = @_;
1003		1222
1004	if ($MODEL) {	1223	if ($MODEL) {
1005	$cb->();	1224	$cb->();
1006		1225
1007	1	1226	undef
1008	} else {	1227	} else {
1009	push @post_detect, $cb;	1228	push @post_detect, $cb;
1010		1229
1011	defined wantarray	1230	defined wantarray
1012	? bless \$cb, "AnyEvent::Util::postdetect"	1231	? bless \$cb, "AnyEvent::Util::postdetect"
…		…
1018	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1237	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1019	}	1238	}
1020		1239
1021	sub detect() {	1240	sub detect() {
1022	unless ($MODEL) {	1241	unless ($MODEL) {
1023	no strict 'refs';
1024	local $SIG{__DIE__};	1242	local $SIG{__DIE__};
1025		1243
1026	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1244	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1027	my $model = "AnyEvent::Impl::$1";	1245	my $model = "AnyEvent::Impl::$1";
1028	if (eval "require $model") {	1246	if (eval "require $model") {
1029	$MODEL = $model;	1247	$MODEL = $model;
1030	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1248	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1031	} else {	1249	} else {
1032	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1250	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1033	}	1251	}
1034	}	1252	}
1035		1253
1036	# check for already loaded models	1254	# check for already loaded models
1037	unless ($MODEL) {	1255	unless ($MODEL) {
1038	for (@REGISTRY, @models) {	1256	for (@REGISTRY, @models) {
1039	my ($package, $model) = @$_;	1257	my ($package, $model) = @$_;
1040	if (${"$package\::VERSION"} > 0) {	1258	if (${"$package\::VERSION"} > 0) {
1041	if (eval "require $model") {	1259	if (eval "require $model") {
1042	$MODEL = $model;	1260	$MODEL = $model;
1043	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1261	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1044	last;	1262	last;
1045	}	1263	}
1046	}	1264	}
1047	}	1265	}
1048		1266
1049	unless ($MODEL) {	1267	unless ($MODEL) {
1050	# try to load a model	1268	# try to autoload a model
1051
1052	for (@REGISTRY, @models) {	1269	for (@REGISTRY, @models) {
1053	my ($package, $model) = @$_;	1270	my ($package, $model, $autoload) = @$_;
		1271	if (
		1272	$autoload
1054	if (eval "require $package"	1273	and eval "require $package"
1055	and ${"$package\::VERSION"} > 0	1274	and ${"$package\::VERSION"} > 0
1056	and eval "require $model") {	1275	and eval "require $model"
		1276	) {
1057	$MODEL = $model;	1277	$MODEL = $model;
1058	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1278	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1059	last;	1279	last;
1060	}	1280	}
1061	}	1281	}
1062		1282
1063	$MODEL	1283	$MODEL
…		…
1079		1299
1080	sub AUTOLOAD {	1300	sub AUTOLOAD {
1081	(my $func = $AUTOLOAD) =~ s/.*://;	1301	(my $func = $AUTOLOAD) =~ s/.*://;
1082		1302
1083	$method{$func}	1303	$method{$func}
1084	or croak "$func: not a valid method for AnyEvent objects";	1304	or Carp::croak "$func: not a valid method for AnyEvent objects";
1085		1305
1086	detect unless $MODEL;	1306	detect unless $MODEL;
1087		1307
1088	my $class = shift;	1308	my $class = shift;
1089	$class->$func (@_);	1309	$class->$func (@_);
…		…
1094	# allow only one watcher per fd, so we dup it to get a different one).	1314	# allow only one watcher per fd, so we dup it to get a different one).
1095	sub _dupfh($$;$$) {	1315	sub _dupfh($$;$$) {
1096	my ($poll, $fh, $r, $w) = @_;	1316	my ($poll, $fh, $r, $w) = @_;
1097		1317
1098	# cygwin requires the fh mode to be matching, unix doesn't	1318	# cygwin requires the fh mode to be matching, unix doesn't
1099	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1319	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1100	: $poll eq "w" ? ($w, ">")
1101	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1102		1320
1103	open my $fh2, "$mode&" . fileno $fh	1321	open my $fh2, $mode, $fh
1104	or die "cannot dup() filehandle: $!,";	1322	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1105		1323
1106	# we assume CLOEXEC is already set by perl in all important cases	1324	# we assume CLOEXEC is already set by perl in all important cases
1107		1325
1108	($fh2, $rw)	1326	($fh2, $rw)
1109	}	1327	}
1110		1328
		1329	=head1 SIMPLIFIED AE API
		1330
		1331	Starting with version 5.0, AnyEvent officially supports a second, much
		1332	simpler, API that is designed to reduce the calling, typing and memory
		1333	overhead.
		1334
		1335	See the L<AE> manpage for details.
		1336
		1337	=cut
		1338
		1339	package AE;
		1340
		1341	our $VERSION = $AnyEvent::VERSION;
		1342
		1343	sub io($$$) {
		1344	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1345	}
		1346
		1347	sub timer($$$) {
		1348	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1349	}
		1350
		1351	sub signal($$) {
		1352	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1353	}
		1354
		1355	sub child($$) {
		1356	AnyEvent->child (pid => $_[0], cb => $_[1])
		1357	}
		1358
		1359	sub idle($) {
		1360	AnyEvent->idle (cb => $_[0])
		1361	}
		1362
		1363	sub cv(;&) {
		1364	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1365	}
		1366
		1367	sub now() {
		1368	AnyEvent->now
		1369	}
		1370
		1371	sub now_update() {
		1372	AnyEvent->now_update
		1373	}
		1374
		1375	sub time() {
		1376	AnyEvent->time
		1377	}
		1378
1111	package AnyEvent::Base;	1379	package AnyEvent::Base;
1112		1380
1113	# default implementations for many methods	1381	# default implementations for many methods
1114		1382
1115	BEGIN {	1383	sub _time() {
		1384	# probe for availability of Time::HiRes
1116	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1385	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1386	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1117	*_time = \&Time::HiRes::time;	1387	*_time = \&Time::HiRes::time;
1118	# if (eval "use POSIX (); (POSIX::times())...	1388	# if (eval "use POSIX (); (POSIX::times())...
1119	} else {	1389	} else {
		1390	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1120	*_time = sub { time }; # epic fail	1391	*_time = sub { time }; # epic fail
1121	}	1392	}
		1393
		1394	&_time
1122	}	1395	}
1123		1396
1124	sub time { _time }	1397	sub time { _time }
1125	sub now { _time }	1398	sub now { _time }
1126	sub now_update { }	1399	sub now_update { }
…		…
1131	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1404	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1132	}	1405	}
1133		1406
1134	# default implementation for ->signal	1407	# default implementation for ->signal
1135		1408
		1409	our $HAVE_ASYNC_INTERRUPT;
		1410
		1411	sub _have_async_interrupt() {
		1412	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1413	&& eval "use Async::Interrupt 1.02 (); 1")
		1414	unless defined $HAVE_ASYNC_INTERRUPT;
		1415
		1416	$HAVE_ASYNC_INTERRUPT
		1417	}
		1418
1136	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1419	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1420	our (%SIG_ASY, %SIG_ASY_W);
		1421	our ($SIG_COUNT, $SIG_TW);
1137		1422
1138	sub _signal_exec {	1423	sub _signal_exec {
		1424	$HAVE_ASYNC_INTERRUPT
		1425	? $SIGPIPE_R->drain
1139	sysread $SIGPIPE_R, my $dummy, 4;	1426	: sysread $SIGPIPE_R, (my $dummy), 9;
1140		1427
1141	while (%SIG_EV) {	1428	while (%SIG_EV) {
1142	for (keys %SIG_EV) {	1429	for (keys %SIG_EV) {
1143	delete $SIG_EV{$_};	1430	delete $SIG_EV{$_};
1144	$_->() for values %{ $SIG_CB{$_} || {} };	1431	$_->() for values %{ $SIG_CB{$_} || {} };
1145	}	1432	}
1146	}	1433	}
1147	}	1434	}
1148		1435
		1436	# install a dummy wakeup watcher to reduce signal catching latency
		1437	sub _sig_add() {
		1438	unless ($SIG_COUNT++) {
		1439	# try to align timer on a full-second boundary, if possible
		1440	my $NOW = AE::now;
		1441
		1442	$SIG_TW = AE::timer
		1443	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1444	$MAX_SIGNAL_LATENCY,
		1445	sub { } # just for the PERL_ASYNC_CHECK
		1446	;
		1447	}
		1448	}
		1449
		1450	sub _sig_del {
		1451	undef $SIG_TW
		1452	unless --$SIG_COUNT;
		1453	}
		1454
		1455	our $_sig_name_init; $_sig_name_init = sub {
		1456	eval q{ # poor man's autoloading
		1457	undef $_sig_name_init;
		1458
		1459	if (_have_async_interrupt) {
		1460	*sig2num = \&Async::Interrupt::sig2num;
		1461	*sig2name = \&Async::Interrupt::sig2name;
		1462	} else {
		1463	require Config;
		1464
		1465	my %signame2num;
		1466	@signame2num{ split ' ', $Config::Config{sig_name} }
		1467	= split ' ', $Config::Config{sig_num};
		1468
		1469	my @signum2name;
		1470	@signum2name[values %signame2num] = keys %signame2num;
		1471
		1472	*sig2num = sub($) {
		1473	$_[0] > 0 ? shift : $signame2num{+shift}
		1474	};
		1475	*sig2name = sub ($) {
		1476	$_[0] > 0 ? $signum2name[+shift] : shift
		1477	};
		1478	}
		1479	};
		1480	die if $@;
		1481	};
		1482
		1483	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1484	sub sig2name($) { &$_sig_name_init; &sig2name }
		1485
1149	sub signal {	1486	sub signal {
1150	my (undef, %arg) = @_;	1487	eval q{ # poor man's autoloading {}
		1488	# probe for availability of Async::Interrupt
		1489	if (_have_async_interrupt) {
		1490	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1151		1491
1152	unless ($SIGPIPE_R) {	1492	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1153	require Fcntl;	1493	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1154		1494
1155	if (AnyEvent::WIN32) {
1156	require AnyEvent::Util;
1157
1158	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1159	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1160	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1161	} else {	1495	} else {
		1496	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1497
		1498	require Fcntl;
		1499
		1500	if (AnyEvent::WIN32) {
		1501	require AnyEvent::Util;
		1502
		1503	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1504	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1505	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1506	} else {
1162	pipe $SIGPIPE_R, $SIGPIPE_W;	1507	pipe $SIGPIPE_R, $SIGPIPE_W;
1163	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1508	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1164	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1509	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1165		1510
1166	# not strictly required, as $^F is normally 2, but let's make sure...	1511	# not strictly required, as $^F is normally 2, but let's make sure...
1167	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1512	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1168	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1513	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1514	}
		1515
		1516	$SIGPIPE_R
		1517	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1518
		1519	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1169	}	1520	}
1170		1521
1171	$SIGPIPE_R	1522	*signal = sub {
1172	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1523	my (undef, %arg) = @_;
1173		1524
1174	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1175	}
1176
1177	my $signal = uc $arg{signal}	1525	my $signal = uc $arg{signal}
1178	or Carp::croak "required option 'signal' is missing";	1526	or Carp::croak "required option 'signal' is missing";
1179		1527
		1528	if ($HAVE_ASYNC_INTERRUPT) {
		1529	# async::interrupt
		1530
		1531	$signal = sig2num $signal;
1180	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1532	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1533
		1534	$SIG_ASY{$signal} ||= new Async::Interrupt
		1535	cb => sub { undef $SIG_EV{$signal} },
		1536	signal => $signal,
		1537	pipe => [$SIGPIPE_R->filenos],
		1538	pipe_autodrain => 0,
		1539	;
		1540
		1541	} else {
		1542	# pure perl
		1543
		1544	# AE::Util has been loaded in signal
		1545	$signal = sig2name $signal;
		1546	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1547
1181	$SIG{$signal} ||= sub {	1548	$SIG{$signal} ||= sub {
1182	local $!;	1549	local $!;
1183	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1550	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1184	undef $SIG_EV{$signal};	1551	undef $SIG_EV{$signal};
		1552	};
		1553
		1554	# can't do signal processing without introducing races in pure perl,
		1555	# so limit the signal latency.
		1556	_sig_add;
		1557	}
		1558
		1559	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1560	};
		1561
		1562	*AnyEvent::Base::signal::DESTROY = sub {
		1563	my ($signal, $cb) = @{$_[0]};
		1564
		1565	_sig_del;
		1566
		1567	delete $SIG_CB{$signal}{$cb};
		1568
		1569	$HAVE_ASYNC_INTERRUPT
		1570	? delete $SIG_ASY{$signal}
		1571	: # delete doesn't work with older perls - they then
		1572	# print weird messages, or just unconditionally exit
		1573	# instead of getting the default action.
		1574	undef $SIG{$signal}
		1575	unless keys %{ $SIG_CB{$signal} };
		1576	};
1185	};	1577	};
1186		1578	die if $@;
1187	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1579	&signal
1188	}
1189
1190	sub AnyEvent::Base::signal::DESTROY {
1191	my ($signal, $cb) = @{$_[0]};
1192
1193	delete $SIG_CB{$signal}{$cb};
1194
1195	# delete doesn't work with older perls - they then
1196	# print weird messages, or just unconditionally exit
1197	# instead of getting the default action.
1198	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1199	}	1580	}
1200		1581
1201	# default implementation for ->child	1582	# default implementation for ->child
1202		1583
1203	our %PID_CB;	1584	our %PID_CB;
1204	our $CHLD_W;	1585	our $CHLD_W;
1205	our $CHLD_DELAY_W;	1586	our $CHLD_DELAY_W;
1206	our $WNOHANG;	1587	our $WNOHANG;
1207		1588
		1589	sub _emit_childstatus($$) {
		1590	my (undef, $rpid, $rstatus) = @_;
		1591
		1592	$_->($rpid, $rstatus)
		1593	for values %{ $PID_CB{$rpid} || {} },
		1594	values %{ $PID_CB{0} || {} };
		1595	}
		1596
1208	sub _sigchld {	1597	sub _sigchld {
		1598	my $pid;
		1599
		1600	AnyEvent->_emit_childstatus ($pid, $?)
1209	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1601	while ($pid = waitpid -1, $WNOHANG) > 0;
1210	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),
1211	(values %{ $PID_CB{0} || {} });
1212	}
1213	}	1602	}
1214		1603
1215	sub child {	1604	sub child {
1216	my (undef, %arg) = @_;	1605	my (undef, %arg) = @_;
1217		1606
1218	defined (my $pid = $arg{pid} + 0)	1607	defined (my $pid = $arg{pid} + 0)
1219	or Carp::croak "required option 'pid' is missing";	1608	or Carp::croak "required option 'pid' is missing";
1220		1609
1221	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1610	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1222		1611
		1612	# WNOHANG is almost cetrainly 1 everywhere
		1613	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1614	? 1
1223	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1615	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1224		1616
1225	unless ($CHLD_W) {	1617	unless ($CHLD_W) {
1226	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1618	$CHLD_W = AE::signal CHLD => \&_sigchld;
1227	# child could be a zombie already, so make at least one round	1619	# child could be a zombie already, so make at least one round
1228	&_sigchld;	1620	&_sigchld;
1229	}	1621	}
1230		1622
1231	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1623	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
…		…
1257	# never use more then 50% of the time for the idle watcher,	1649	# never use more then 50% of the time for the idle watcher,
1258	# within some limits	1650	# within some limits
1259	$w = 0.0001 if $w < 0.0001;	1651	$w = 0.0001 if $w < 0.0001;
1260	$w = 5 if $w > 5;	1652	$w = 5 if $w > 5;
1261		1653
1262	$w = AnyEvent->timer (after => $w, cb => $rcb);	1654	$w = AE::timer $w, 0, $rcb;
1263	} else {	1655	} else {
1264	# clean up...	1656	# clean up...
1265	undef $w;	1657	undef $w;
1266	undef $rcb;	1658	undef $rcb;
1267	}	1659	}
1268	};	1660	};
1269		1661
1270	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1662	$w = AE::timer 0.05, 0, $rcb;
1271		1663
1272	bless \\$cb, "AnyEvent::Base::idle"	1664	bless \\$cb, "AnyEvent::Base::idle"
1273	}	1665	}
1274		1666
1275	sub AnyEvent::Base::idle::DESTROY {	1667	sub AnyEvent::Base::idle::DESTROY {
…		…
1280		1672
1281	our @ISA = AnyEvent::CondVar::Base::;	1673	our @ISA = AnyEvent::CondVar::Base::;
1282		1674
1283	package AnyEvent::CondVar::Base;	1675	package AnyEvent::CondVar::Base;
1284		1676
1285	use overload	1677	#use overload
1286	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1678	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1287	fallback => 1;	1679	# fallback => 1;
		1680
		1681	# save 300+ kilobytes by dirtily hardcoding overloading
		1682	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1683	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1684	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1685	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1686
		1687	our $WAITING;
1288		1688
1289	sub _send {	1689	sub _send {
1290	# nop	1690	# nop
1291	}	1691	}
1292		1692
…		…
1305	sub ready {	1705	sub ready {
1306	$_[0]{_ae_sent}	1706	$_[0]{_ae_sent}
1307	}	1707	}
1308		1708
1309	sub _wait {	1709	sub _wait {
		1710	$WAITING
		1711	and !$_[0]{_ae_sent}
		1712	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1713
		1714	local $WAITING = 1;
1310	AnyEvent->one_event while !$_[0]{_ae_sent};	1715	AnyEvent->one_event while !$_[0]{_ae_sent};
1311	}	1716	}
1312		1717
1313	sub recv {	1718	sub recv {
1314	$_[0]->_wait;	1719	$_[0]->_wait;
…		…
1316	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1721	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1317	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1722	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1318	}	1723	}
1319		1724
1320	sub cb {	1725	sub cb {
1321	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1726	my $cv = shift;
		1727
		1728	@_
		1729	and $cv->{_ae_cb} = shift
		1730	and $cv->{_ae_sent}
		1731	and (delete $cv->{_ae_cb})->($cv);
		1732
1322	$_[0]{_ae_cb}	1733	$cv->{_ae_cb}
1323	}	1734	}
1324		1735
1325	sub begin {	1736	sub begin {
1326	++$_[0]{_ae_counter};	1737	++$_[0]{_ae_counter};
1327	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1738	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1376	C<PERL_ANYEVENT_MODEL>.	1787	C<PERL_ANYEVENT_MODEL>.
1377		1788
1378	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1789	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1379	model it chooses.	1790	model it chooses.
1380		1791
		1792	When set to C<8> or higher, then AnyEvent will report extra information on
		1793	which optional modules it loads and how it implements certain features.
		1794
1381	=item C<PERL_ANYEVENT_STRICT>	1795	=item C<PERL_ANYEVENT_STRICT>
1382		1796
1383	AnyEvent does not do much argument checking by default, as thorough	1797	AnyEvent does not do much argument checking by default, as thorough
1384	argument checking is very costly. Setting this variable to a true value	1798	argument checking is very costly. Setting this variable to a true value
1385	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1799	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1386	check the arguments passed to most method calls. If it finds any problems,	1800	check the arguments passed to most method calls. If it finds any problems,
1387	it will croak.	1801	it will croak.
1388		1802
1389	In other words, enables "strict" mode.	1803	In other words, enables "strict" mode.
1390		1804
1391	Unlike C<use strict>, it is definitely recommended to keep it off in	1805	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1392	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1806	>>, it is definitely recommended to keep it off in production. Keeping
1393	developing programs can be very useful, however.	1807	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1808	can be very useful, however.
1394		1809
1395	=item C<PERL_ANYEVENT_MODEL>	1810	=item C<PERL_ANYEVENT_MODEL>
1396		1811
1397	This can be used to specify the event model to be used by AnyEvent, before	1812	This can be used to specify the event model to be used by AnyEvent, before
1398	auto detection and -probing kicks in. It must be a string consisting	1813	auto detection and -probing kicks in. It must be a string consisting
…		…
1441		1856
1442	=item C<PERL_ANYEVENT_MAX_FORKS>	1857	=item C<PERL_ANYEVENT_MAX_FORKS>
1443		1858
1444	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1859	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1445	will create in parallel.	1860	will create in parallel.
		1861
		1862	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1863
		1864	The default value for the C<max_outstanding> parameter for the default DNS
		1865	resolver - this is the maximum number of parallel DNS requests that are
		1866	sent to the DNS server.
		1867
		1868	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1869
		1870	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1871	configuration) in the default resolver. When set to the empty string, no
		1872	default config will be used.
		1873
		1874	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1875
		1876	When neither C<ca_file> nor C<ca_path> was specified during
		1877	L<AnyEvent::TLS> context creation, and either of these environment
		1878	variables exist, they will be used to specify CA certificate locations
		1879	instead of a system-dependent default.
		1880
		1881	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1882
		1883	When these are set to C<1>, then the respective modules are not
		1884	loaded. Mostly good for testing AnyEvent itself.
1446		1885
1447	=back	1886	=back
1448		1887
1449	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1888	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1450		1889
…		…
1508	warn "read: $input\n"; # output what has been read	1947	warn "read: $input\n"; # output what has been read
1509	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1948	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1510	},	1949	},
1511	);	1950	);
1512		1951
1513	my $time_watcher; # can only be used once
1514
1515	sub new_timer {
1516	$timer = AnyEvent->timer (after => 1, cb => sub {	1952	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1517	warn "timeout\n"; # print 'timeout' about every second	1953	warn "timeout\n"; # print 'timeout' at most every second
1518	&new_timer; # and restart the time
1519	});	1954	});
1520	}
1521
1522	new_timer; # create first timer
1523		1955
1524	$cv->recv; # wait until user enters /^q/i	1956	$cv->recv; # wait until user enters /^q/i
1525		1957
1526	=head1 REAL-WORLD EXAMPLE	1958	=head1 REAL-WORLD EXAMPLE
1527		1959
…		…
1658	through AnyEvent. The benchmark creates a lot of timers (with a zero	2090	through AnyEvent. The benchmark creates a lot of timers (with a zero
1659	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2091	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1660	which it is), lets them fire exactly once and destroys them again.	2092	which it is), lets them fire exactly once and destroys them again.
1661		2093
1662	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2094	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1663	distribution.	2095	distribution. It uses the L<AE> interface, which makes a real difference
		2096	for the EV and Perl backends only.
1664		2097
1665	=head3 Explanation of the columns	2098	=head3 Explanation of the columns
1666		2099
1667	I<watcher> is the number of event watchers created/destroyed. Since	2100	I<watcher> is the number of event watchers created/destroyed. Since
1668	different event models feature vastly different performances, each event	2101	different event models feature vastly different performances, each event
…		…
1689	watcher.	2122	watcher.
1690		2123
1691	=head3 Results	2124	=head3 Results
1692		2125
1693	name watchers bytes create invoke destroy comment	2126	name watchers bytes create invoke destroy comment
1694	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2127	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1695	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2128	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1696	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2129	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1697	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2130	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1698	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2131	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1699	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2132	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2133	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2134	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1700	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2135	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1701	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2136	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1702	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2137	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1703	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2138	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1704		2139
1705	=head3 Discussion	2140	=head3 Discussion
1706		2141
1707	The benchmark does I<not> measure scalability of the event loop very	2142	The benchmark does I<not> measure scalability of the event loop very
1708	well. For example, a select-based event loop (such as the pure perl one)	2143	well. For example, a select-based event loop (such as the pure perl one)
…		…
1720	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2155	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1721	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2156	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1722	cycles with POE.	2157	cycles with POE.
1723		2158
1724	C<EV> is the sole leader regarding speed and memory use, which are both	2159	C<EV> is the sole leader regarding speed and memory use, which are both
1725	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2160	maximal/minimal, respectively. When using the L<AE> API there is zero
		2161	overhead (when going through the AnyEvent API create is about 5-6 times
		2162	slower, with other times being equal, so still uses far less memory than
1726	far less memory than any other event loop and is still faster than Event	2163	any other event loop and is still faster than Event natively).
1727	natively.
1728		2164
1729	The pure perl implementation is hit in a few sweet spots (both the	2165	The pure perl implementation is hit in a few sweet spots (both the
1730	constant timeout and the use of a single fd hit optimisations in the perl	2166	constant timeout and the use of a single fd hit optimisations in the perl
1731	interpreter and the backend itself). Nevertheless this shows that it	2167	interpreter and the backend itself). Nevertheless this shows that it
1732	adds very little overhead in itself. Like any select-based backend its	2168	adds very little overhead in itself. Like any select-based backend its
1733	performance becomes really bad with lots of file descriptors (and few of	2169	performance becomes really bad with lots of file descriptors (and few of
1734	them active), of course, but this was not subject of this benchmark.	2170	them active), of course, but this was not subject of this benchmark.
1735		2171
1736	The C<Event> module has a relatively high setup and callback invocation	2172	The C<Event> module has a relatively high setup and callback invocation
1737	cost, but overall scores in on the third place.	2173	cost, but overall scores in on the third place.
		2174
		2175	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2176	when using its pure perl backend.
1738		2177
1739	C<Glib>'s memory usage is quite a bit higher, but it features a	2178	C<Glib>'s memory usage is quite a bit higher, but it features a
1740	faster callback invocation and overall ends up in the same class as	2179	faster callback invocation and overall ends up in the same class as
1741	C<Event>. However, Glib scales extremely badly, doubling the number of	2180	C<Event>. However, Glib scales extremely badly, doubling the number of
1742	watchers increases the processing time by more than a factor of four,	2181	watchers increases the processing time by more than a factor of four,
…		…
1803	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2242	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1804	(1%) are active. This mirrors the activity of large servers with many	2243	(1%) are active. This mirrors the activity of large servers with many
1805	connections, most of which are idle at any one point in time.	2244	connections, most of which are idle at any one point in time.
1806		2245
1807	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2246	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1808	distribution.	2247	distribution. It uses the L<AE> interface, which makes a real difference
		2248	for the EV and Perl backends only.
1809		2249
1810	=head3 Explanation of the columns	2250	=head3 Explanation of the columns
1811		2251
1812	I<sockets> is the number of sockets, and twice the number of "servers" (as	2252	I<sockets> is the number of sockets, and twice the number of "servers" (as
1813	each server has a read and write socket end).	2253	each server has a read and write socket end).
…		…
1820	it to another server. This includes deleting the old timeout and creating	2260	it to another server. This includes deleting the old timeout and creating
1821	a new one that moves the timeout into the future.	2261	a new one that moves the timeout into the future.
1822		2262
1823	=head3 Results	2263	=head3 Results
1824		2264
1825	name sockets create request	2265	name sockets create request
1826	EV 20000 69.01 11.16	2266	EV 20000 62.66 7.99
1827	Perl 20000 73.32 35.87	2267	Perl 20000 68.32 32.64
1828	Event 20000 212.62 257.32	2268	IOAsync 20000 174.06 101.15 epoll
1829	Glib 20000 651.16 1896.30	2269	IOAsync 20000 174.67 610.84 poll
		2270	Event 20000 202.69 242.91
		2271	Glib 20000 557.01 1689.52
1830	POE 20000 349.67 12317.24 uses POE::Loop::Event	2272	POE 20000 341.54 12086.32 uses POE::Loop::Event
1831		2273
1832	=head3 Discussion	2274	=head3 Discussion
1833		2275
1834	This benchmark I<does> measure scalability and overall performance of the	2276	This benchmark I<does> measure scalability and overall performance of the
1835	particular event loop.	2277	particular event loop.
…		…
1837	EV is again fastest. Since it is using epoll on my system, the setup time	2279	EV is again fastest. Since it is using epoll on my system, the setup time
1838	is relatively high, though.	2280	is relatively high, though.
1839		2281
1840	Perl surprisingly comes second. It is much faster than the C-based event	2282	Perl surprisingly comes second. It is much faster than the C-based event
1841	loops Event and Glib.	2283	loops Event and Glib.
		2284
		2285	IO::Async performs very well when using its epoll backend, and still quite
		2286	good compared to Glib when using its pure perl backend.
1842		2287
1843	Event suffers from high setup time as well (look at its code and you will	2288	Event suffers from high setup time as well (look at its code and you will
1844	understand why). Callback invocation also has a high overhead compared to	2289	understand why). Callback invocation also has a high overhead compared to
1845	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2290	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1846	uses select or poll in basically all documented configurations.	2291	uses select or poll in basically all documented configurations.
…		…
1958	As you can see, the AnyEvent + EV combination even beats the	2403	As you can see, the AnyEvent + EV combination even beats the
1959	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2404	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
1960	backend easily beats IO::Lambda and POE.	2405	backend easily beats IO::Lambda and POE.
1961		2406
1962	And even the 100% non-blocking version written using the high-level (and	2407	And even the 100% non-blocking version written using the high-level (and
1963	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2408	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
1964	large margin, even though it does all of DNS, tcp-connect and socket I/O	2409	higher level ("unoptimised") abstractions by a large margin, even though
1965	in a non-blocking way.	2410	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
1966		2411
1967	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2412	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
1968	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2413	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
1969	part of the IO::lambda distribution and were used without any changes.	2414	part of the IO::Lambda distribution and were used without any changes.
1970		2415
1971		2416
1972	=head1 SIGNALS	2417	=head1 SIGNALS
1973		2418
1974	AnyEvent currently installs handlers for these signals:	2419	AnyEvent currently installs handlers for these signals:
…		…
1979		2424
1980	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2425	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1981	emulation for event loops that do not support them natively. Also, some	2426	emulation for event loops that do not support them natively. Also, some
1982	event loops install a similar handler.	2427	event loops install a similar handler.
1983		2428
1984	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will	2429	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
1985	reset it to default, to avoid losing child exit statuses.	2430	AnyEvent will reset it to default, to avoid losing child exit statuses.
1986		2431
1987	=item SIGPIPE	2432	=item SIGPIPE
1988		2433
1989	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2434	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1990	when AnyEvent gets loaded.	2435	when AnyEvent gets loaded.
…		…
2008	if $SIG{CHLD} eq 'IGNORE';	2453	if $SIG{CHLD} eq 'IGNORE';
2009		2454
2010	$SIG{PIPE} = sub { }	2455	$SIG{PIPE} = sub { }
2011	unless defined $SIG{PIPE};	2456	unless defined $SIG{PIPE};
2012		2457
		2458	=head1 RECOMMENDED/OPTIONAL MODULES
		2459
		2460	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2461	it's built-in modules) are required to use it.
		2462
		2463	That does not mean that AnyEvent won't take advantage of some additional
		2464	modules if they are installed.
		2465
		2466	This section explains which additional modules will be used, and how they
		2467	affect AnyEvent's operation.
		2468
		2469	=over 4
		2470
		2471	=item L<Async::Interrupt>
		2472
		2473	This slightly arcane module is used to implement fast signal handling: To
		2474	my knowledge, there is no way to do completely race-free and quick
		2475	signal handling in pure perl. To ensure that signals still get
		2476	delivered, AnyEvent will start an interval timer to wake up perl (and
		2477	catch the signals) with some delay (default is 10 seconds, look for
		2478	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2479
		2480	If this module is available, then it will be used to implement signal
		2481	catching, which means that signals will not be delayed, and the event loop
		2482	will not be interrupted regularly, which is more efficient (and good for
		2483	battery life on laptops).
		2484
		2485	This affects not just the pure-perl event loop, but also other event loops
		2486	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2487
		2488	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2489	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2490	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2491	does nothing for those backends.
		2492
		2493	=item L<EV>
		2494
		2495	This module isn't really "optional", as it is simply one of the backend
		2496	event loops that AnyEvent can use. However, it is simply the best event
		2497	loop available in terms of features, speed and stability: It supports
		2498	the AnyEvent API optimally, implements all the watcher types in XS, does
		2499	automatic timer adjustments even when no monotonic clock is available,
		2500	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2501	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2502	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2503
		2504	=item L<Guard>
		2505
		2506	The guard module, when used, will be used to implement
		2507	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2508	lot less memory), but otherwise doesn't affect guard operation much. It is
		2509	purely used for performance.
		2510
		2511	=item L<JSON> and L<JSON::XS>
		2512
		2513	One of these modules is required when you want to read or write JSON data
		2514	via L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2515	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2516
		2517	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2518	installed.
		2519
		2520	=item L<Net::SSLeay>
		2521
		2522	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2523	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2524	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2525
		2526	=item L<Time::HiRes>
		2527
		2528	This module is part of perl since release 5.008. It will be used when the
		2529	chosen event library does not come with a timing source on it's own. The
		2530	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2531	try to use a monotonic clock for timing stability.
		2532
		2533	=back
		2534
		2535
2013	=head1 FORK	2536	=head1 FORK
2014		2537
2015	Most event libraries are not fork-safe. The ones who are usually are	2538	Most event libraries are not fork-safe. The ones who are usually are
2016	because they rely on inefficient but fork-safe C<select> or C<poll>	2539	because they rely on inefficient but fork-safe C<select> or C<poll>
2017	calls. Only L<EV> is fully fork-aware.	2540	calls. Only L<EV> is fully fork-aware.
2018		2541
		2542	This means that, in general, you cannot fork and do event processing
		2543	in the child if a watcher was created before the fork (which in turn
		2544	initialises the event library).
		2545
2019	If you have to fork, you must either do so I<before> creating your first	2546	If you have to fork, you must either do so I<before> creating your first
2020	watcher OR you must not use AnyEvent at all in the child.	2547	watcher OR you must not use AnyEvent at all in the child OR you must do
		2548	something completely out of the scope of AnyEvent.
		2549
		2550	The problem of doing event processing in the parent I<and> the child
		2551	is much more complicated: even for backends that I<are> fork-aware or
		2552	fork-safe, their behaviour is not usually what you want: fork clones all
		2553	watchers, that means all timers, I/O watchers etc. are active in both
		2554	parent and child, which is almost never what you want.
2021		2555
2022		2556
2023	=head1 SECURITY CONSIDERATIONS	2557	=head1 SECURITY CONSIDERATIONS
2024		2558
2025	AnyEvent can be forced to load any event model via	2559	AnyEvent can be forced to load any event model via
…		…
2063	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2597	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2064		2598
2065	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2599	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2066	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2600	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2067	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2601	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2068	L<AnyEvent::Impl::POE>.	2602	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2069		2603
2070	Non-blocking file handles, sockets, TCP clients and	2604	Non-blocking file handles, sockets, TCP clients and
2071	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2605	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2072		2606
2073	Asynchronous DNS: L<AnyEvent::DNS>.	2607	Asynchronous DNS: L<AnyEvent::DNS>.
2074		2608
2075	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2609	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2610	L<Coro::Event>,
2076		2611
2077	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2612	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2613	L<AnyEvent::HTTP>.
2078		2614
2079		2615
2080	=head1 AUTHOR	2616	=head1 AUTHOR
2081		2617
2082	Marc Lehmann <schmorp@schmorp.de>	2618	Marc Lehmann <schmorp@schmorp.de>

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