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Revision 1.317 by root, Wed Mar 24 21:22:57 2010 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> (or a naked 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
…		…
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
429	Sometimes there is a need to do something, but it is not so important	506	$w = AnyEvent->idle (cb => <callback>);
430	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
432	attention by the event loop".
433		507
434	Idle watchers ideally get invoked when the event loop has nothing	508	Repeatedly invoke the callback after the process becomes idle, until
435	better to do, just before it would block the process to wait for new	509	either the watcher is destroyed or new events have been detected.
436	events. Instead of blocking, the idle watcher is invoked.
437		510
438	Most event loops unfortunately do not really support idle watchers (only	511	Idle watchers are useful when there is a need to do something, but it
		512	is not so important (or wise) to do it instantly. The callback will be
		513	invoked only when there is "nothing better to do", which is usually
		514	defined as "all outstanding events have been handled and no new events
		515	have been detected". That means that idle watchers ideally get invoked
		516	when the event loop has just polled for new events but none have been
		517	detected. Instead of blocking to wait for more events, the idle watchers
		518	will be invoked.
		519
		520	Unfortunately, most event loops do not really support idle watchers (only
439	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	521	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
440	will simply call the callback "from time to time".	522	will simply call the callback "from time to time".
441		523
442	Example: read lines from STDIN, but only process them when the	524	Example: read lines from STDIN, but only process them when the
443	program is otherwise idle:	525	program is otherwise idle:
…		…
459	});	541	});
460	});	542	});
461		543
462	=head2 CONDITION VARIABLES	544	=head2 CONDITION VARIABLES
463		545
		546	$cv = AnyEvent->condvar;
		547
		548	$cv->send (<list>);
		549	my @res = $cv->recv;
		550
464	If you are familiar with some event loops you will know that all of them	551	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	552	require you to run some blocking "loop", "run" or similar function that
466	will actively watch for new events and call your callbacks.	553	will actively watch for new events and call your callbacks.
467		554
468	AnyEvent is different, it expects somebody else to run the event loop and	555	AnyEvent is slightly different: it expects somebody else to run the event
469	will only block when necessary (usually when told by the user).	556	loop and will only block when necessary (usually when told by the user).
470		557
471	The instrument to do that is called a "condition variable", so called	558	The instrument to do that is called a "condition variable", so called
472	because they represent a condition that must become true.	559	because they represent a condition that must become true.
473		560
		561	Now is probably a good time to look at the examples further below.
		562
474	Condition variables can be created by calling the C<< AnyEvent->condvar	563	Condition variables can be created by calling the C<< AnyEvent->condvar
475	>> method, usually without arguments. The only argument pair allowed is	564	>> 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	565	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	566	becomes true, with the condition variable as the first argument (but not
479	the results).	567	the results).
480		568
481	After creation, the condition variable is "false" until it becomes "true"	569	After creation, the condition variable is "false" until it becomes "true"
…		…
486	Condition variables are similar to callbacks, except that you can	574	Condition variables are similar to callbacks, except that you can
487	optionally wait for them. They can also be called merge points - points	575	optionally wait for them. They can also be called merge points - points
488	in time where multiple outstanding events have been processed. And yet	576	in time where multiple outstanding events have been processed. And yet
489	another way to call them is transactions - each condition variable can be	577	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	578	used to represent a transaction, which finishes at some point and delivers
491	a result.	579	a result. And yet some people know them as "futures" - a promise to
		580	compute/deliver something that you can wait for.
492		581
493	Condition variables are very useful to signal that something has finished,	582	Condition variables are very useful to signal that something has finished,
494	for example, if you write a module that does asynchronous http requests,	583	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	584	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	585	availability of results. The user can either act when the callback is
…		…
530	after => 1,	619	after => 1,
531	cb => sub { $result_ready->send },	620	cb => sub { $result_ready->send },
532	);	621	);
533		622
534	# this "blocks" (while handling events) till the callback	623	# this "blocks" (while handling events) till the callback
535	# calls send	624	# calls ->send
536	$result_ready->recv;	625	$result_ready->recv;
537		626
538	Example: wait for a timer, but take advantage of the fact that	627	Example: wait for a timer, but take advantage of the fact that condition
539	condition variables are also code references.	628	variables are also callable directly.
540		629
541	my $done = AnyEvent->condvar;	630	my $done = AnyEvent->condvar;
542	my $delay = AnyEvent->timer (after => 5, cb => $done);	631	my $delay = AnyEvent->timer (after => 5, cb => $done);
543	$done->recv;	632	$done->recv;
544		633
…		…
550		639
551	...	640	...
552		641
553	my @info = $couchdb->info->recv;	642	my @info = $couchdb->info->recv;
554		643
555	And this is how you would just ste a callback to be called whenever the	644	And this is how you would just set a callback to be called whenever the
556	results are available:	645	results are available:
557		646
558	$couchdb->info->cb (sub {	647	$couchdb->info->cb (sub {
559	my @info = $_[0]->recv;	648	my @info = $_[0]->recv;
560	});	649	});
…		…
578	immediately from within send.	667	immediately from within send.
579		668
580	Any arguments passed to the C<send> call will be returned by all	669	Any arguments passed to the C<send> call will be returned by all
581	future C<< ->recv >> calls.	670	future C<< ->recv >> calls.
582		671
583	Condition variables are overloaded so one can call them directly	672	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	673	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	674	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		675
592	=item $cv->croak ($error)	676	=item $cv->croak ($error)
593		677
594	Similar to send, but causes all call's to C<< ->recv >> to invoke	678	Similar to send, but causes all call's to C<< ->recv >> to invoke
595	C<Carp::croak> with the given error message/object/scalar.	679	C<Carp::croak> with the given error message/object/scalar.
596		680
597	This can be used to signal any errors to the condition variable	681	This can be used to signal any errors to the condition variable
598	user/consumer.	682	user/consumer. Doing it this way instead of calling C<croak> directly
		683	delays the error detetcion, but has the overwhelmign advantage that it
		684	diagnoses the error at the place where the result is expected, and not
		685	deep in some event clalback without connection to the actual code causing
		686	the problem.
599		687
600	=item $cv->begin ([group callback])	688	=item $cv->begin ([group callback])
601		689
602	=item $cv->end	690	=item $cv->end
603		691
…		…
605	one. For example, a function that pings many hosts in parallel might want	693	one. For example, a function that pings many hosts in parallel might want
606	to use a condition variable for the whole process.	694	to use a condition variable for the whole process.
607		695
608	Every call to C<< ->begin >> will increment a counter, and every call to	696	Every call to C<< ->begin >> will increment a counter, and every call to
609	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	697	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
610	>>, the (last) callback passed to C<begin> will be executed. That callback	698	>>, the (last) callback passed to C<begin> will be executed, passing the
611	is I<supposed> to call C<< ->send >>, but that is not required. If no	699	condvar as first argument. That callback is I<supposed> to call C<< ->send
612	callback was set, C<send> will be called without any arguments.	700	>>, but that is not required. If no group callback was set, C<send> will
		701	be called without any arguments.
613		702
614	You can think of C<< $cv->send >> giving you an OR condition (one call	703	You can think of C<< $cv->send >> giving you an OR condition (one call
615	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND	704	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
616	condition (all C<begin> calls must be C<end>'ed before the condvar sends).	705	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
617		706
…		…
644	begung can potentially be zero:	733	begung can potentially be zero:
645		734
646	my $cv = AnyEvent->condvar;	735	my $cv = AnyEvent->condvar;
647		736
648	my %result;	737	my %result;
649	$cv->begin (sub { $cv->send (\%result) });	738	$cv->begin (sub { shift->send (\%result) });
650		739
651	for my $host (@list_of_hosts) {	740	for my $host (@list_of_hosts) {
652	$cv->begin;	741	$cv->begin;
653	ping_host_then_call_callback $host, sub {	742	ping_host_then_call_callback $host, sub {
654	$result{$host} = ...;	743	$result{$host} = ...;
…		…
699	function will call C<croak>.	788	function will call C<croak>.
700		789
701	In list context, all parameters passed to C<send> will be returned,	790	In list context, all parameters passed to C<send> will be returned,
702	in scalar context only the first one will be returned.	791	in scalar context only the first one will be returned.
703		792
		793	Note that doing a blocking wait in a callback is not supported by any
		794	event loop, that is, recursive invocation of a blocking C<< ->recv
		795	>> is not allowed, and the C<recv> call will C<croak> if such a
		796	condition is detected. This condition can be slightly loosened by using
		797	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		798	any thread that doesn't run the event loop itself.
		799
704	Not all event models support a blocking wait - some die in that case	800	Not all event models support a blocking wait - some die in that case
705	(programs might want to do that to stay interactive), so I<if you are	801	(programs might want to do that to stay interactive), so I<if you are
706	using this from a module, never require a blocking wait>, but let the	802	using this from a module, never require a blocking wait>. Instead, let the
707	caller decide whether the call will block or not (for example, by coupling	803	caller decide whether the call will block or not (for example, by coupling
708	condition variables with some kind of request results and supporting	804	condition variables with some kind of request results and supporting
709	callbacks so the caller knows that getting the result will not block,	805	callbacks so the caller knows that getting the result will not block,
710	while still supporting blocking waits if the caller so desires).	806	while still supporting blocking waits if the caller so desires).
711		807
712	Another reason I<never> to C<< ->recv >> in a module is that you cannot
713	sensibly have two C<< ->recv >>'s in parallel, as that would require
714	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
715	can supply.
716
717	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
718	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
719	versions and also integrates coroutines into AnyEvent, making blocking
720	C<< ->recv >> calls perfectly safe as long as they are done from another
721	coroutine (one that doesn't run the event loop).
722
723	You can ensure that C<< -recv >> never blocks by setting a callback and	808	You can ensure that C<< -recv >> never blocks by setting a callback and
724	only calling C<< ->recv >> from within that callback (or at a later	809	only calling C<< ->recv >> from within that callback (or at a later
725	time). This will work even when the event loop does not support blocking	810	time). This will work even when the event loop does not support blocking
726	waits otherwise.	811	waits otherwise.
727		812
…		…
733	=item $cb = $cv->cb ($cb->($cv))	818	=item $cb = $cv->cb ($cb->($cv))
734		819
735	This is a mutator function that returns the callback set and optionally	820	This is a mutator function that returns the callback set and optionally
736	replaces it before doing so.	821	replaces it before doing so.
737		822
738	The callback will be called when the condition becomes "true", i.e. when	823	The callback will be called when the condition becomes (or already was)
739	C<send> or C<croak> are called, with the only argument being the condition	824	"true", i.e. when C<send> or C<croak> are called (or were called), with
740	variable itself. Calling C<recv> inside the callback or at any later time	825	the only argument being the condition variable itself. Calling C<recv>
741	is guaranteed not to block.	826	inside the callback or at any later time is guaranteed not to block.
742		827
743	=back	828	=back
744		829
		830	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		831
		832	The available backend classes are (every class has its own manpage):
		833
		834	=over 4
		835
		836	=item Backends that are autoprobed when no other event loop can be found.
		837
		838	EV is the preferred backend when no other event loop seems to be in
		839	use. If EV is not installed, then AnyEvent will fall back to its own
		840	pure-perl implementation, which is available everywhere as it comes with
		841	AnyEvent itself.
		842
		843	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		844	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		845
		846	=item Backends that are transparently being picked up when they are used.
		847
		848	These will be used when they are currently loaded when the first watcher
		849	is created, in which case it is assumed that the application is using
		850	them. This means that AnyEvent will automatically pick the right backend
		851	when the main program loads an event module before anything starts to
		852	create watchers. Nothing special needs to be done by the main program.
		853
		854	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		855	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		856	AnyEvent::Impl::Tk based on Tk, very broken.
		857	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		858	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		859	AnyEvent::Impl::Irssi used when running within irssi.
		860
		861	=item Backends with special needs.
		862
		863	Qt requires the Qt::Application to be instantiated first, but will
		864	otherwise be picked up automatically. As long as the main program
		865	instantiates the application before any AnyEvent watchers are created,
		866	everything should just work.
		867
		868	AnyEvent::Impl::Qt based on Qt.
		869
		870	Support for IO::Async can only be partial, as it is too broken and
		871	architecturally limited to even support the AnyEvent API. It also
		872	is the only event loop that needs the loop to be set explicitly, so
		873	it can only be used by a main program knowing about AnyEvent. See
		874	L<AnyEvent::Impl::Async> for the gory details.
		875
		876	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		877
		878	=item Event loops that are indirectly supported via other backends.
		879
		880	Some event loops can be supported via other modules:
		881
		882	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		883
		884	B<WxWidgets> has no support for watching file handles. However, you can
		885	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		886	polls 20 times per second, which was considered to be too horrible to even
		887	consider for AnyEvent.
		888
		889	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		890	backend, so it can be supported through POE.
		891
		892	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		893	load L<POE> when detecting them, in the hope that POE will pick them up,
		894	in which case everything will be automatic.
		895
		896	=back
		897
745	=head1 GLOBAL VARIABLES AND FUNCTIONS	898	=head1 GLOBAL VARIABLES AND FUNCTIONS
746		899
		900	These are not normally required to use AnyEvent, but can be useful to
		901	write AnyEvent extension modules.
		902
747	=over 4	903	=over 4
748		904
749	=item $AnyEvent::MODEL	905	=item $AnyEvent::MODEL
750		906
751	Contains C<undef> until the first watcher is being created. Then it	907	Contains C<undef> until the first watcher is being created, before the
		908	backend has been autodetected.
		909
752	contains the event model that is being used, which is the name of the	910	Afterwards it contains the event model that is being used, which is the
753	Perl class implementing the model. This class is usually one of the	911	name of the Perl class implementing the model. This class is usually one
754	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	912	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
755	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	913	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
756		914	will be C<urxvt::anyevent>).
757	The known classes so far are:
758
759	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
760	AnyEvent::Impl::Event based on Event, second best choice.
761	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
762	AnyEvent::Impl::Glib based on Glib, third-best choice.
763	AnyEvent::Impl::Tk based on Tk, very bad choice.
764	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
765	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
766	AnyEvent::Impl::POE based on POE, not generic enough for full support.
767
768	# warning, support for IO::Async is only partial, as it is too broken
769	# and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
770	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
771
772	There is no support for WxWidgets, as WxWidgets has no support for
773	watching file handles. However, you can use WxWidgets through the
774	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
775	second, which was considered to be too horrible to even consider for
776	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
777	it's adaptor.
778
779	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
780	autodetecting them.
781		915
782	=item AnyEvent::detect	916	=item AnyEvent::detect
783		917
784	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	918	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
785	if necessary. You should only call this function right before you would	919	if necessary. You should only call this function right before you would
786	have created an AnyEvent watcher anyway, that is, as late as possible at	920	have created an AnyEvent watcher anyway, that is, as late as possible at
787	runtime.	921	runtime, and not e.g. while initialising of your module.
		922
		923	If you need to do some initialisation before AnyEvent watchers are
		924	created, use C<post_detect>.
788		925
789	=item $guard = AnyEvent::post_detect { BLOCK }	926	=item $guard = AnyEvent::post_detect { BLOCK }
790		927
791	Arranges for the code block to be executed as soon as the event model is	928	Arranges for the code block to be executed as soon as the event model is
792	autodetected (or immediately if this has already happened).	929	autodetected (or immediately if this has already happened).
793		930
		931	The block will be executed I<after> the actual backend has been detected
		932	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		933	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		934	other initialisations - see the sources of L<AnyEvent::Strict> or
		935	L<AnyEvent::AIO> to see how this is used.
		936
		937	The most common usage is to create some global watchers, without forcing
		938	event module detection too early, for example, L<AnyEvent::AIO> creates
		939	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		940	avoid autodetecting the event module at load time.
		941
794	If called in scalar or list context, then it creates and returns an object	942	If called in scalar or list context, then it creates and returns an object
795	that automatically removes the callback again when it is destroyed. See	943	that automatically removes the callback again when it is destroyed (or
		944	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
796	L<Coro::BDB> for a case where this is useful.	945	a case where this is useful.
		946
		947	Example: Create a watcher for the IO::AIO module and store it in
		948	C<$WATCHER>. Only do so after the event loop is initialised, though.
		949
		950	our WATCHER;
		951
		952	my $guard = AnyEvent::post_detect {
		953	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		954	};
		955
		956	# the ||= is important in case post_detect immediately runs the block,
		957	# as to not clobber the newly-created watcher. assigning both watcher and
		958	# post_detect guard to the same variable has the advantage of users being
		959	# able to just C<undef $WATCHER> if the watcher causes them grief.
		960
		961	$WATCHER ||= $guard;
797		962
798	=item @AnyEvent::post_detect	963	=item @AnyEvent::post_detect
799		964
800	If there are any code references in this array (you can C<push> to it	965	If there are any code references in this array (you can C<push> to it
801	before or after loading AnyEvent), then they will called directly after	966	before or after loading AnyEvent), then they will called directly after
802	the event loop has been chosen.	967	the event loop has been chosen.
803		968
804	You should check C<$AnyEvent::MODEL> before adding to this array, though:	969	You should check C<$AnyEvent::MODEL> before adding to this array, though:
805	if it contains a true value then the event loop has already been detected,	970	if it is defined then the event loop has already been detected, and the
806	and the array will be ignored.	971	array will be ignored.
807		972
808	Best use C<AnyEvent::post_detect { BLOCK }> instead.	973	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		974	it, as it takes care of these details.
		975
		976	This variable is mainly useful for modules that can do something useful
		977	when AnyEvent is used and thus want to know when it is initialised, but do
		978	not need to even load it by default. This array provides the means to hook
		979	into AnyEvent passively, without loading it.
		980
		981	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		982	together, you could put this into Coro (this is the actual code used by
		983	Coro to accomplish this):
		984
		985	if (defined $AnyEvent::MODEL) {
		986	# AnyEvent already initialised, so load Coro::AnyEvent
		987	require Coro::AnyEvent;
		988	} else {
		989	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		990	# as soon as it is
		991	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		992	}
809		993
810	=back	994	=back
811		995
812	=head1 WHAT TO DO IN A MODULE	996	=head1 WHAT TO DO IN A MODULE
813		997
…		…
960		1144
961	=cut	1145	=cut
962		1146
963	package AnyEvent;	1147	package AnyEvent;
964		1148
965	no warnings;	1149	# basically a tuned-down version of common::sense
966	use strict qw(vars subs);	1150	sub common_sense {
		1151	# from common:.sense 1.0
		1152	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
		1153	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1154	$^H |= 0x00000600;
		1155	}
967		1156
		1157	BEGIN { AnyEvent::common_sense }
		1158
968	use Carp;	1159	use Carp ();
969		1160
970	our $VERSION = 4.8;	1161	our $VERSION = '5.251';
971	our $MODEL;	1162	our $MODEL;
972		1163
973	our $AUTOLOAD;	1164	our $AUTOLOAD;
974	our @ISA;	1165	our @ISA;
975		1166
976	our @REGISTRY;	1167	our @REGISTRY;
977		1168
978	our $WIN32;	1169	our $VERBOSE;
979		1170
980	BEGIN {	1171	BEGIN {
981	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1172	require "AnyEvent/constants.pl";
		1173
982	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1174	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
983		1175
984	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1176	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
985	if ${^TAINT};	1177	if ${^TAINT};
986	}
987		1178
988	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1179	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1180
		1181	}
		1182
		1183	our $MAX_SIGNAL_LATENCY = 10;
989		1184
990	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1185	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
991		1186
992	{	1187	{
993	my $idx;	1188	my $idx;
…		…
995	for reverse split /\s*,\s*/,	1190	for reverse split /\s*,\s*/,
996	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1191	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
997	}	1192	}
998		1193
999	my @models = (	1194	my @models = (
1000	[EV:: => AnyEvent::Impl::EV::],	1195	[EV:: => AnyEvent::Impl::EV:: , 1],
1001	[Event:: => AnyEvent::Impl::Event::],
1002	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1196	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1003	# everything below here will not be autoprobed	1197	# everything below here will not (normally) be autoprobed
1004	# as the pureperl backend should work everywhere	1198	# as the pureperl backend should work everywhere
1005	# and is usually faster	1199	# and is usually faster
		1200	[Event:: => AnyEvent::Impl::Event::, 1],
		1201	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1202	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1203	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1006	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1204	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1007	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
1008	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1009	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1205	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1010	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1206	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1011	[Wx:: => AnyEvent::Impl::POE::],	1207	[Wx:: => AnyEvent::Impl::POE::],
1012	[Prima:: => AnyEvent::Impl::POE::],	1208	[Prima:: => AnyEvent::Impl::POE::],
1013	# IO::Async is just too broken - we would need workaorunds for its	1209	# IO::Async is just too broken - we would need workarounds for its
1014	# byzantine signal and broken child handling, among others.	1210	# byzantine signal and broken child handling, among others.
1015	# IO::Async is rather hard to detect, as it doesn't have any	1211	# IO::Async is rather hard to detect, as it doesn't have any
1016	# obvious default class.	1212	# obvious default class.
1017	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program	1213	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1018	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program	1214	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1019	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program	1215	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1216	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1020	);	1217	);
1021		1218
1022	our %method = map +($_ => 1),	1219	our %method = map +($_ => 1),
1023	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1220	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
1024		1221
1025	our @post_detect;	1222	our @post_detect;
1026		1223
1027	sub post_detect(&) {	1224	sub post_detect(&) {
1028	my ($cb) = @_;	1225	my ($cb) = @_;
1029		1226
1030	if ($MODEL) {
1031	$cb->();
1032
1033	1
1034	} else {
1035	push @post_detect, $cb;	1227	push @post_detect, $cb;
1036		1228
1037	defined wantarray	1229	defined wantarray
1038	? bless \$cb, "AnyEvent::Util::postdetect"	1230	? bless \$cb, "AnyEvent::Util::postdetect"
1039	: ()	1231	: ()
1040	}
1041	}	1232	}
1042		1233
1043	sub AnyEvent::Util::postdetect::DESTROY {	1234	sub AnyEvent::Util::postdetect::DESTROY {
1044	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1235	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1045	}	1236	}
1046		1237
1047	sub detect() {	1238	sub detect() {
		1239	# free some memory
		1240	*detect = sub () { $MODEL };
		1241
		1242	local $!; # for good measure
		1243	local $SIG{__DIE__};
		1244
		1245	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1246	my $model = "AnyEvent::Impl::$1";
		1247	if (eval "require $model") {
		1248	$MODEL = $model;
		1249	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1250	} else {
		1251	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1252	}
		1253	}
		1254
		1255	# check for already loaded models
1048	unless ($MODEL) {	1256	unless ($MODEL) {
1049	no strict 'refs';	1257	for (@REGISTRY, @models) {
1050	local $SIG{__DIE__};	1258	my ($package, $model) = @$_;
1051		1259	if (${"$package\::VERSION"} > 0) {
1052	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1053	my $model = "AnyEvent::Impl::$1";
1054	if (eval "require $model") {	1260	if (eval "require $model") {
1055	$MODEL = $model;	1261	$MODEL = $model;
1056	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1262	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1057	} else {	1263	last;
1058	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1264	}
1059	}	1265	}
1060	}	1266	}
1061		1267
1062	# check for already loaded models
1063	unless ($MODEL) {	1268	unless ($MODEL) {
		1269	# try to autoload a model
1064	for (@REGISTRY, @models) {	1270	for (@REGISTRY, @models) {
1065	my ($package, $model) = @$_;	1271	my ($package, $model, $autoload) = @$_;
		1272	if (
		1273	$autoload
		1274	and eval "require $package"
1066	if (${"$package\::VERSION"} > 0) {	1275	and ${"$package\::VERSION"} > 0
1067	if (eval "require $model") {	1276	and eval "require $model"
		1277	) {
1068	$MODEL = $model;	1278	$MODEL = $model;
1069	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1279	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1070	last;	1280	last;
1071	}
1072	}	1281	}
1073	}	1282	}
1074		1283
1075	unless ($MODEL) {
1076	# try to load a model
1077
1078	for (@REGISTRY, @models) {
1079	my ($package, $model) = @$_;
1080	if (eval "require $package"
1081	and ${"$package\::VERSION"} > 0
1082	and eval "require $model") {
1083	$MODEL = $model;
1084	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1085	last;
1086	}
1087	}
1088
1089	$MODEL	1284	$MODEL
1090	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1285	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
1091	}
1092	}	1286	}
1093
1094	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1095
1096	unshift @ISA, $MODEL;
1097
1098	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1099
1100	(shift @post_detect)->() while @post_detect;
1101	}	1287	}
		1288
		1289	@models = (); # free probe data
		1290
		1291	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1292	unshift @ISA, $MODEL;
		1293
		1294	# now nuke some methods that are overriden by the backend.
		1295	# SUPER is not allowed.
		1296	for (qw(time signal child idle)) {
		1297	undef &{"AnyEvent::Base::$_"}
		1298	if defined &{"$MODEL\::$_"};
		1299	}
		1300
		1301	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1302
		1303	(shift @post_detect)->() while @post_detect;
		1304
		1305	*post_detect = sub(&) {
		1306	shift->();
		1307
		1308	undef
		1309	};
1102		1310
1103	$MODEL	1311	$MODEL
1104	}	1312	}
1105		1313
1106	sub AUTOLOAD {	1314	sub AUTOLOAD {
1107	(my $func = $AUTOLOAD) =~ s/.*://;	1315	(my $func = $AUTOLOAD) =~ s/.*://;
1108		1316
1109	$method{$func}	1317	$method{$func}
1110	or croak "$func: not a valid method for AnyEvent objects";	1318	or Carp::croak "$func: not a valid AnyEvent class method";
1111		1319
1112	detect unless $MODEL;	1320	detect;
1113		1321
1114	my $class = shift;	1322	my $class = shift;
1115	$class->$func (@_);	1323	$class->$func (@_);
1116	}	1324	}
1117		1325
…		…
1120	# allow only one watcher per fd, so we dup it to get a different one).	1328	# allow only one watcher per fd, so we dup it to get a different one).
1121	sub _dupfh($$;$$) {	1329	sub _dupfh($$;$$) {
1122	my ($poll, $fh, $r, $w) = @_;	1330	my ($poll, $fh, $r, $w) = @_;
1123		1331
1124	# cygwin requires the fh mode to be matching, unix doesn't	1332	# cygwin requires the fh mode to be matching, unix doesn't
1125	my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">");	1333	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1126		1334
1127	open my $fh2, "$mode&", $fh	1335	open my $fh2, $mode, $fh
1128	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";	1336	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1129		1337
1130	# we assume CLOEXEC is already set by perl in all important cases	1338	# we assume CLOEXEC is already set by perl in all important cases
1131		1339
1132	($fh2, $rw)	1340	($fh2, $rw)
1133	}	1341	}
1134		1342
		1343	=head1 SIMPLIFIED AE API
		1344
		1345	Starting with version 5.0, AnyEvent officially supports a second, much
		1346	simpler, API that is designed to reduce the calling, typing and memory
		1347	overhead.
		1348
		1349	See the L<AE> manpage for details.
		1350
		1351	=cut
		1352
		1353	package AE;
		1354
		1355	our $VERSION = $AnyEvent::VERSION;
		1356
		1357	sub io($$$) {
		1358	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1359	}
		1360
		1361	sub timer($$$) {
		1362	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1363	}
		1364
		1365	sub signal($$) {
		1366	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1367	}
		1368
		1369	sub child($$) {
		1370	AnyEvent->child (pid => $_[0], cb => $_[1])
		1371	}
		1372
		1373	sub idle($) {
		1374	AnyEvent->idle (cb => $_[0])
		1375	}
		1376
		1377	sub cv(;&) {
		1378	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1379	}
		1380
		1381	sub now() {
		1382	AnyEvent->now
		1383	}
		1384
		1385	sub now_update() {
		1386	AnyEvent->now_update
		1387	}
		1388
		1389	sub time() {
		1390	AnyEvent->time
		1391	}
		1392
1135	package AnyEvent::Base;	1393	package AnyEvent::Base;
1136		1394
1137	# default implementations for many methods	1395	# default implementations for many methods
1138		1396
1139	BEGIN {	1397	sub time {
		1398	eval q{ # poor man's autoloading {}
		1399	# probe for availability of Time::HiRes
1140	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1400	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1401	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1141	*_time = \&Time::HiRes::time;	1402	*AE::time = \&Time::HiRes::time;
1142	# if (eval "use POSIX (); (POSIX::times())...	1403	# if (eval "use POSIX (); (POSIX::times())...
1143	} else {	1404	} else {
		1405	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1144	*_time = sub { time }; # epic fail	1406	*AE::time = sub (){ time }; # epic fail
		1407	}
		1408
		1409	*time = sub { AE::time }; # different prototypes
		1410	};
		1411	die if $@;
		1412
		1413	&time
		1414	}
		1415
		1416	*now = \&time;
		1417
		1418	sub now_update { }
		1419
		1420	# default implementation for ->condvar
		1421
		1422	sub condvar {
		1423	eval q{ # poor man's autoloading {}
		1424	*condvar = sub {
		1425	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1426	};
		1427
		1428	*AE::cv = sub (;&) {
		1429	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1430	};
		1431	};
		1432	die if $@;
		1433
		1434	&condvar
		1435	}
		1436
		1437	# default implementation for ->signal
		1438
		1439	our $HAVE_ASYNC_INTERRUPT;
		1440
		1441	sub _have_async_interrupt() {
		1442	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1443	&& eval "use Async::Interrupt 1.02 (); 1")
		1444	unless defined $HAVE_ASYNC_INTERRUPT;
		1445
		1446	$HAVE_ASYNC_INTERRUPT
		1447	}
		1448
		1449	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1450	our (%SIG_ASY, %SIG_ASY_W);
		1451	our ($SIG_COUNT, $SIG_TW);
		1452
		1453	# install a dummy wakeup watcher to reduce signal catching latency
		1454	# used by Impls
		1455	sub _sig_add() {
		1456	unless ($SIG_COUNT++) {
		1457	# try to align timer on a full-second boundary, if possible
		1458	my $NOW = AE::now;
		1459
		1460	$SIG_TW = AE::timer
		1461	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1462	$MAX_SIGNAL_LATENCY,
		1463	sub { } # just for the PERL_ASYNC_CHECK
		1464	;
1145	}	1465	}
1146	}	1466	}
1147		1467
1148	sub time { _time }	1468	sub _sig_del {
1149	sub now { _time }	1469	undef $SIG_TW
1150	sub now_update { }	1470	unless --$SIG_COUNT;
1151
1152	# default implementation for ->condvar
1153
1154	sub condvar {
1155	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1156	}	1471	}
1157		1472
1158	# default implementation for ->signal	1473	our $_sig_name_init; $_sig_name_init = sub {
		1474	eval q{ # poor man's autoloading {}
		1475	undef $_sig_name_init;
1159		1476
1160	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1477	if (_have_async_interrupt) {
		1478	*sig2num = \&Async::Interrupt::sig2num;
		1479	*sig2name = \&Async::Interrupt::sig2name;
		1480	} else {
		1481	require Config;
1161		1482
1162	sub _signal_exec {	1483	my %signame2num;
1163	sysread $SIGPIPE_R, my $dummy, 4;	1484	@signame2num{ split ' ', $Config::Config{sig_name} }
		1485	= split ' ', $Config::Config{sig_num};
1164		1486
1165	while (%SIG_EV) {	1487	my @signum2name;
1166	for (keys %SIG_EV) {	1488	@signum2name[values %signame2num] = keys %signame2num;
1167	delete $SIG_EV{$_};	1489
1168	$_->() for values %{ $SIG_CB{$_} || {} };	1490	*sig2num = sub($) {
		1491	$_[0] > 0 ? shift : $signame2num{+shift}
		1492	};
		1493	*sig2name = sub ($) {
		1494	$_[0] > 0 ? $signum2name[+shift] : shift
		1495	};
1169	}	1496	}
1170	}	1497	};
1171	}	1498	die if $@;
		1499	};
		1500
		1501	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1502	sub sig2name($) { &$_sig_name_init; &sig2name }
1172		1503
1173	sub signal {	1504	sub signal {
1174	my (undef, %arg) = @_;	1505	eval q{ # poor man's autoloading {}
		1506	# probe for availability of Async::Interrupt
		1507	if (_have_async_interrupt) {
		1508	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1175		1509
1176	unless ($SIGPIPE_R) {	1510	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1177	require Fcntl;	1511	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1178		1512
1179	if (AnyEvent::WIN32) {
1180	require AnyEvent::Util;
1181
1182	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1183	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1184	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1185	} else {	1513	} else {
		1514	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1515
		1516	if (AnyEvent::WIN32) {
		1517	require AnyEvent::Util;
		1518
		1519	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1520	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1521	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1522	} else {
1186	pipe $SIGPIPE_R, $SIGPIPE_W;	1523	pipe $SIGPIPE_R, $SIGPIPE_W;
1187	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1524	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1188	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1525	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1189		1526
1190	# not strictly required, as $^F is normally 2, but let's make sure...	1527	# not strictly required, as $^F is normally 2, but let's make sure...
1191	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1528	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1192	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1529	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1530	}
		1531
		1532	$SIGPIPE_R
		1533	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1534
		1535	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1193	}	1536	}
1194		1537
1195	$SIGPIPE_R	1538	*signal = $HAVE_ASYNC_INTERRUPT
1196	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1539	? sub {
		1540	my (undef, %arg) = @_;
1197		1541
1198	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1542	# async::interrupt
1199	}
1200
1201	my $signal = uc $arg{signal}	1543	my $signal = sig2num $arg{signal};
1202	or Carp::croak "required option 'signal' is missing";
1203
1204	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1544	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1545
		1546	$SIG_ASY{$signal} ||= new Async::Interrupt
		1547	cb => sub { undef $SIG_EV{$signal} },
		1548	signal => $signal,
		1549	pipe => [$SIGPIPE_R->filenos],
		1550	pipe_autodrain => 0,
		1551	;
		1552
		1553	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1554	}
		1555	: sub {
		1556	my (undef, %arg) = @_;
		1557
		1558	# pure perl
		1559	my $signal = sig2name $arg{signal};
		1560	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1561
1205	$SIG{$signal} ||= sub {	1562	$SIG{$signal} ||= sub {
1206	local $!;	1563	local $!;
1207	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1564	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1208	undef $SIG_EV{$signal};	1565	undef $SIG_EV{$signal};
		1566	};
		1567
		1568	# can't do signal processing without introducing races in pure perl,
		1569	# so limit the signal latency.
		1570	_sig_add;
		1571
		1572	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1573	}
		1574	;
		1575
		1576	*AnyEvent::Base::signal::DESTROY = sub {
		1577	my ($signal, $cb) = @{$_[0]};
		1578
		1579	_sig_del;
		1580
		1581	delete $SIG_CB{$signal}{$cb};
		1582
		1583	$HAVE_ASYNC_INTERRUPT
		1584	? delete $SIG_ASY{$signal}
		1585	: # delete doesn't work with older perls - they then
		1586	# print weird messages, or just unconditionally exit
		1587	# instead of getting the default action.
		1588	undef $SIG{$signal}
		1589	unless keys %{ $SIG_CB{$signal} };
		1590	};
		1591
		1592	*_signal_exec = sub {
		1593	$HAVE_ASYNC_INTERRUPT
		1594	? $SIGPIPE_R->drain
		1595	: sysread $SIGPIPE_R, (my $dummy), 9;
		1596
		1597	while (%SIG_EV) {
		1598	for (keys %SIG_EV) {
		1599	delete $SIG_EV{$_};
		1600	$_->() for values %{ $SIG_CB{$_} || {} };
		1601	}
		1602	}
		1603	};
1209	};	1604	};
		1605	die if $@;
1210		1606
1211	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1607	&signal
1212	}
1213
1214	sub AnyEvent::Base::signal::DESTROY {
1215	my ($signal, $cb) = @{$_[0]};
1216
1217	delete $SIG_CB{$signal}{$cb};
1218
1219	# delete doesn't work with older perls - they then
1220	# print weird messages, or just unconditionally exit
1221	# instead of getting the default action.
1222	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1223	}	1608	}
1224		1609
1225	# default implementation for ->child	1610	# default implementation for ->child
1226		1611
1227	our %PID_CB;	1612	our %PID_CB;
1228	our $CHLD_W;	1613	our $CHLD_W;
1229	our $CHLD_DELAY_W;	1614	our $CHLD_DELAY_W;
1230	our $WNOHANG;	1615	our $WNOHANG;
1231		1616
1232	sub _sigchld {	1617	# used by many Impl's
1233	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1618	sub _emit_childstatus($$) {
		1619	my (undef, $rpid, $rstatus) = @_;
		1620
		1621	$_->($rpid, $rstatus)
1234	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1622	for values %{ $PID_CB{$rpid} || {} },
1235	(values %{ $PID_CB{0} || {} });	1623	values %{ $PID_CB{0} || {} };
1236	}
1237	}	1624	}
1238		1625
1239	sub child {	1626	sub child {
		1627	eval q{ # poor man's autoloading {}
		1628	*_sigchld = sub {
		1629	my $pid;
		1630
		1631	AnyEvent->_emit_childstatus ($pid, $?)
		1632	while ($pid = waitpid -1, $WNOHANG) > 0;
		1633	};
		1634
		1635	*child = sub {
1240	my (undef, %arg) = @_;	1636	my (undef, %arg) = @_;
1241		1637
1242	defined (my $pid = $arg{pid} + 0)	1638	defined (my $pid = $arg{pid} + 0)
1243	or Carp::croak "required option 'pid' is missing";	1639	or Carp::croak "required option 'pid' is missing";
1244		1640
1245	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1641	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1246		1642
		1643	# WNOHANG is almost cetrainly 1 everywhere
		1644	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1645	? 1
1247	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1646	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1248		1647
1249	unless ($CHLD_W) {	1648	unless ($CHLD_W) {
1250	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1649	$CHLD_W = AE::signal CHLD => \&_sigchld;
1251	# child could be a zombie already, so make at least one round	1650	# child could be a zombie already, so make at least one round
1252	&_sigchld;	1651	&_sigchld;
1253	}	1652	}
1254		1653
1255	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1654	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1256	}	1655	};
1257		1656
1258	sub AnyEvent::Base::child::DESTROY {	1657	*AnyEvent::Base::child::DESTROY = sub {
1259	my ($pid, $cb) = @{$_[0]};	1658	my ($pid, $cb) = @{$_[0]};
1260		1659
1261	delete $PID_CB{$pid}{$cb};	1660	delete $PID_CB{$pid}{$cb};
1262	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1661	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1263		1662
1264	undef $CHLD_W unless keys %PID_CB;	1663	undef $CHLD_W unless keys %PID_CB;
		1664	};
		1665	};
		1666	die if $@;
		1667
		1668	&child
1265	}	1669	}
1266		1670
1267	# idle emulation is done by simply using a timer, regardless	1671	# idle emulation is done by simply using a timer, regardless
1268	# of whether the process is idle or not, and not letting	1672	# of whether the process is idle or not, and not letting
1269	# the callback use more than 50% of the time.	1673	# the callback use more than 50% of the time.
1270	sub idle {	1674	sub idle {
		1675	eval q{ # poor man's autoloading {}
		1676	*idle = sub {
1271	my (undef, %arg) = @_;	1677	my (undef, %arg) = @_;
1272		1678
1273	my ($cb, $w, $rcb) = $arg{cb};	1679	my ($cb, $w, $rcb) = $arg{cb};
1274		1680
1275	$rcb = sub {	1681	$rcb = sub {
1276	if ($cb) {	1682	if ($cb) {
1277	$w = _time;	1683	$w = _time;
1278	&$cb;	1684	&$cb;
1279	$w = _time - $w;	1685	$w = _time - $w;
1280		1686
1281	# never use more then 50% of the time for the idle watcher,	1687	# never use more then 50% of the time for the idle watcher,
1282	# within some limits	1688	# within some limits
1283	$w = 0.0001 if $w < 0.0001;	1689	$w = 0.0001 if $w < 0.0001;
1284	$w = 5 if $w > 5;	1690	$w = 5 if $w > 5;
1285		1691
1286	$w = AnyEvent->timer (after => $w, cb => $rcb);	1692	$w = AE::timer $w, 0, $rcb;
1287	} else {	1693	} else {
1288	# clean up...	1694	# clean up...
1289	undef $w;	1695	undef $w;
1290	undef $rcb;	1696	undef $rcb;
		1697	}
		1698	};
		1699
		1700	$w = AE::timer 0.05, 0, $rcb;
		1701
		1702	bless \\$cb, "AnyEvent::Base::idle"
1291	}	1703	};
		1704
		1705	*AnyEvent::Base::idle::DESTROY = sub {
		1706	undef $${$_[0]};
		1707	};
1292	};	1708	};
		1709	die if $@;
1293		1710
1294	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1711	&idle
1295
1296	bless \\$cb, "AnyEvent::Base::idle"
1297	}
1298
1299	sub AnyEvent::Base::idle::DESTROY {
1300	undef $${$_[0]};
1301	}	1712	}
1302		1713
1303	package AnyEvent::CondVar;	1714	package AnyEvent::CondVar;
1304		1715
1305	our @ISA = AnyEvent::CondVar::Base::;	1716	our @ISA = AnyEvent::CondVar::Base::;
1306		1717
1307	package AnyEvent::CondVar::Base;	1718	package AnyEvent::CondVar::Base;
1308		1719
1309	use overload	1720	#use overload
1310	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1721	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1311	fallback => 1;	1722	# fallback => 1;
		1723
		1724	# save 300+ kilobytes by dirtily hardcoding overloading
		1725	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1726	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1727	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1728	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1729
		1730	our $WAITING;
1312		1731
1313	sub _send {	1732	sub _send {
1314	# nop	1733	# nop
1315	}	1734	}
1316		1735
…		…
1329	sub ready {	1748	sub ready {
1330	$_[0]{_ae_sent}	1749	$_[0]{_ae_sent}
1331	}	1750	}
1332		1751
1333	sub _wait {	1752	sub _wait {
		1753	$WAITING
		1754	and !$_[0]{_ae_sent}
		1755	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1756
		1757	local $WAITING = 1;
1334	AnyEvent->one_event while !$_[0]{_ae_sent};	1758	AnyEvent->one_event while !$_[0]{_ae_sent};
1335	}	1759	}
1336		1760
1337	sub recv {	1761	sub recv {
1338	$_[0]->_wait;	1762	$_[0]->_wait;
…		…
1340	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1764	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1341	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1765	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1342	}	1766	}
1343		1767
1344	sub cb {	1768	sub cb {
1345	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1769	my $cv = shift;
		1770
		1771	@_
		1772	and $cv->{_ae_cb} = shift
		1773	and $cv->{_ae_sent}
		1774	and (delete $cv->{_ae_cb})->($cv);
		1775
1346	$_[0]{_ae_cb}	1776	$cv->{_ae_cb}
1347	}	1777	}
1348		1778
1349	sub begin {	1779	sub begin {
1350	++$_[0]{_ae_counter};	1780	++$_[0]{_ae_counter};
1351	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1781	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1400	C<PERL_ANYEVENT_MODEL>.	1830	C<PERL_ANYEVENT_MODEL>.
1401		1831
1402	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1832	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1403	model it chooses.	1833	model it chooses.
1404		1834
		1835	When set to C<8> or higher, then AnyEvent will report extra information on
		1836	which optional modules it loads and how it implements certain features.
		1837
1405	=item C<PERL_ANYEVENT_STRICT>	1838	=item C<PERL_ANYEVENT_STRICT>
1406		1839
1407	AnyEvent does not do much argument checking by default, as thorough	1840	AnyEvent does not do much argument checking by default, as thorough
1408	argument checking is very costly. Setting this variable to a true value	1841	argument checking is very costly. Setting this variable to a true value
1409	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1842	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1410	check the arguments passed to most method calls. If it finds any problems,	1843	check the arguments passed to most method calls. If it finds any problems,
1411	it will croak.	1844	it will croak.
1412		1845
1413	In other words, enables "strict" mode.	1846	In other words, enables "strict" mode.
1414		1847
1415	Unlike C<use strict>, it is definitely recommended to keep it off in	1848	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1416	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1849	>>, it is definitely recommended to keep it off in production. Keeping
1417	developing programs can be very useful, however.	1850	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1851	can be very useful, however.
1418		1852
1419	=item C<PERL_ANYEVENT_MODEL>	1853	=item C<PERL_ANYEVENT_MODEL>
1420		1854
1421	This can be used to specify the event model to be used by AnyEvent, before	1855	This can be used to specify the event model to be used by AnyEvent, before
1422	auto detection and -probing kicks in. It must be a string consisting	1856	auto detection and -probing kicks in. It must be a string consisting
…		…
1484		1918
1485	When neither C<ca_file> nor C<ca_path> was specified during	1919	When neither C<ca_file> nor C<ca_path> was specified during
1486	L<AnyEvent::TLS> context creation, and either of these environment	1920	L<AnyEvent::TLS> context creation, and either of these environment
1487	variables exist, they will be used to specify CA certificate locations	1921	variables exist, they will be used to specify CA certificate locations
1488	instead of a system-dependent default.	1922	instead of a system-dependent default.
		1923
		1924	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1925
		1926	When these are set to C<1>, then the respective modules are not
		1927	loaded. Mostly good for testing AnyEvent itself.
1489		1928
1490	=back	1929	=back
1491		1930
1492	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1931	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1493		1932
…		…
1551	warn "read: $input\n"; # output what has been read	1990	warn "read: $input\n"; # output what has been read
1552	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1991	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1553	},	1992	},
1554	);	1993	);
1555		1994
1556	my $time_watcher; # can only be used once
1557
1558	sub new_timer {
1559	$timer = AnyEvent->timer (after => 1, cb => sub {	1995	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1560	warn "timeout\n"; # print 'timeout' about every second	1996	warn "timeout\n"; # print 'timeout' at most every second
1561	&new_timer; # and restart the time
1562	});	1997	});
1563	}
1564
1565	new_timer; # create first timer
1566		1998
1567	$cv->recv; # wait until user enters /^q/i	1999	$cv->recv; # wait until user enters /^q/i
1568		2000
1569	=head1 REAL-WORLD EXAMPLE	2001	=head1 REAL-WORLD EXAMPLE
1570		2002
…		…
1701	through AnyEvent. The benchmark creates a lot of timers (with a zero	2133	through AnyEvent. The benchmark creates a lot of timers (with a zero
1702	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2134	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1703	which it is), lets them fire exactly once and destroys them again.	2135	which it is), lets them fire exactly once and destroys them again.
1704		2136
1705	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2137	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1706	distribution.	2138	distribution. It uses the L<AE> interface, which makes a real difference
		2139	for the EV and Perl backends only.
1707		2140
1708	=head3 Explanation of the columns	2141	=head3 Explanation of the columns
1709		2142
1710	I<watcher> is the number of event watchers created/destroyed. Since	2143	I<watcher> is the number of event watchers created/destroyed. Since
1711	different event models feature vastly different performances, each event	2144	different event models feature vastly different performances, each event
…		…
1732	watcher.	2165	watcher.
1733		2166
1734	=head3 Results	2167	=head3 Results
1735		2168
1736	name watchers bytes create invoke destroy comment	2169	name watchers bytes create invoke destroy comment
1737	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2170	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1738	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2171	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1739	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2172	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1740	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2173	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1741	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2174	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1742	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2175	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1743	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2176	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1744	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2177	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1745	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2178	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1746	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2179	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1747	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2180	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1748	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2181	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1749		2182
1750	=head3 Discussion	2183	=head3 Discussion
1751		2184
1752	The benchmark does I<not> measure scalability of the event loop very	2185	The benchmark does I<not> measure scalability of the event loop very
1753	well. For example, a select-based event loop (such as the pure perl one)	2186	well. For example, a select-based event loop (such as the pure perl one)
…		…
1765	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2198	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1766	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2199	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1767	cycles with POE.	2200	cycles with POE.
1768		2201
1769	C<EV> is the sole leader regarding speed and memory use, which are both	2202	C<EV> is the sole leader regarding speed and memory use, which are both
1770	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2203	maximal/minimal, respectively. When using the L<AE> API there is zero
		2204	overhead (when going through the AnyEvent API create is about 5-6 times
		2205	slower, with other times being equal, so still uses far less memory than
1771	far less memory than any other event loop and is still faster than Event	2206	any other event loop and is still faster than Event natively).
1772	natively.
1773		2207
1774	The pure perl implementation is hit in a few sweet spots (both the	2208	The pure perl implementation is hit in a few sweet spots (both the
1775	constant timeout and the use of a single fd hit optimisations in the perl	2209	constant timeout and the use of a single fd hit optimisations in the perl
1776	interpreter and the backend itself). Nevertheless this shows that it	2210	interpreter and the backend itself). Nevertheless this shows that it
1777	adds very little overhead in itself. Like any select-based backend its	2211	adds very little overhead in itself. Like any select-based backend its
…		…
1851	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2285	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1852	(1%) are active. This mirrors the activity of large servers with many	2286	(1%) are active. This mirrors the activity of large servers with many
1853	connections, most of which are idle at any one point in time.	2287	connections, most of which are idle at any one point in time.
1854		2288
1855	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2289	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1856	distribution.	2290	distribution. It uses the L<AE> interface, which makes a real difference
		2291	for the EV and Perl backends only.
1857		2292
1858	=head3 Explanation of the columns	2293	=head3 Explanation of the columns
1859		2294
1860	I<sockets> is the number of sockets, and twice the number of "servers" (as	2295	I<sockets> is the number of sockets, and twice the number of "servers" (as
1861	each server has a read and write socket end).	2296	each server has a read and write socket end).
…		…
1869	a new one that moves the timeout into the future.	2304	a new one that moves the timeout into the future.
1870		2305
1871	=head3 Results	2306	=head3 Results
1872		2307
1873	name sockets create request	2308	name sockets create request
1874	EV 20000 69.01 11.16	2309	EV 20000 62.66 7.99
1875	Perl 20000 73.32 35.87	2310	Perl 20000 68.32 32.64
1876	IOAsync 20000 157.00 98.14 epoll	2311	IOAsync 20000 174.06 101.15 epoll
1877	IOAsync 20000 159.31 616.06 poll	2312	IOAsync 20000 174.67 610.84 poll
1878	Event 20000 212.62 257.32	2313	Event 20000 202.69 242.91
1879	Glib 20000 651.16 1896.30	2314	Glib 20000 557.01 1689.52
1880	POE 20000 349.67 12317.24 uses POE::Loop::Event	2315	POE 20000 341.54 12086.32 uses POE::Loop::Event
1881		2316
1882	=head3 Discussion	2317	=head3 Discussion
1883		2318
1884	This benchmark I<does> measure scalability and overall performance of the	2319	This benchmark I<does> measure scalability and overall performance of the
1885	particular event loop.	2320	particular event loop.
…		…
2011	As you can see, the AnyEvent + EV combination even beats the	2446	As you can see, the AnyEvent + EV combination even beats the
2012	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2447	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2013	backend easily beats IO::Lambda and POE.	2448	backend easily beats IO::Lambda and POE.
2014		2449
2015	And even the 100% non-blocking version written using the high-level (and	2450	And even the 100% non-blocking version written using the high-level (and
2016	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2451	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2017	large margin, even though it does all of DNS, tcp-connect and socket I/O	2452	higher level ("unoptimised") abstractions by a large margin, even though
2018	in a non-blocking way.	2453	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2019		2454
2020	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2455	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2021	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2456	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2022	part of the IO::lambda distribution and were used without any changes.	2457	part of the IO::Lambda distribution and were used without any changes.
2023		2458
2024		2459
2025	=head1 SIGNALS	2460	=head1 SIGNALS
2026		2461
2027	AnyEvent currently installs handlers for these signals:	2462	AnyEvent currently installs handlers for these signals:
…		…
2032		2467
2033	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2468	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
2034	emulation for event loops that do not support them natively. Also, some	2469	emulation for event loops that do not support them natively. Also, some
2035	event loops install a similar handler.	2470	event loops install a similar handler.
2036		2471
2037	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will	2472	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2038	reset it to default, to avoid losing child exit statuses.	2473	AnyEvent will reset it to default, to avoid losing child exit statuses.
2039		2474
2040	=item SIGPIPE	2475	=item SIGPIPE
2041		2476
2042	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2477	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
2043	when AnyEvent gets loaded.	2478	when AnyEvent gets loaded.
…		…
2061	if $SIG{CHLD} eq 'IGNORE';	2496	if $SIG{CHLD} eq 'IGNORE';
2062		2497
2063	$SIG{PIPE} = sub { }	2498	$SIG{PIPE} = sub { }
2064	unless defined $SIG{PIPE};	2499	unless defined $SIG{PIPE};
2065		2500
		2501	=head1 RECOMMENDED/OPTIONAL MODULES
		2502
		2503	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2504	it's built-in modules) are required to use it.
		2505
		2506	That does not mean that AnyEvent won't take advantage of some additional
		2507	modules if they are installed.
		2508
		2509	This section explains which additional modules will be used, and how they
		2510	affect AnyEvent's operation.
		2511
		2512	=over 4
		2513
		2514	=item L<Async::Interrupt>
		2515
		2516	This slightly arcane module is used to implement fast signal handling: To
		2517	my knowledge, there is no way to do completely race-free and quick
		2518	signal handling in pure perl. To ensure that signals still get
		2519	delivered, AnyEvent will start an interval timer to wake up perl (and
		2520	catch the signals) with some delay (default is 10 seconds, look for
		2521	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2522
		2523	If this module is available, then it will be used to implement signal
		2524	catching, which means that signals will not be delayed, and the event loop
		2525	will not be interrupted regularly, which is more efficient (and good for
		2526	battery life on laptops).
		2527
		2528	This affects not just the pure-perl event loop, but also other event loops
		2529	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2530
		2531	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2532	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2533	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2534	does nothing for those backends.
		2535
		2536	=item L<EV>
		2537
		2538	This module isn't really "optional", as it is simply one of the backend
		2539	event loops that AnyEvent can use. However, it is simply the best event
		2540	loop available in terms of features, speed and stability: It supports
		2541	the AnyEvent API optimally, implements all the watcher types in XS, does
		2542	automatic timer adjustments even when no monotonic clock is available,
		2543	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2544	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2545	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2546
		2547	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2548	then this module will do nothing for you.
		2549
		2550	=item L<Guard>
		2551
		2552	The guard module, when used, will be used to implement
		2553	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2554	lot less memory), but otherwise doesn't affect guard operation much. It is
		2555	purely used for performance.
		2556
		2557	=item L<JSON> and L<JSON::XS>
		2558
		2559	One of these modules is required when you want to read or write JSON data
		2560	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2561	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2562
		2563	=item L<Net::SSLeay>
		2564
		2565	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2566	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2567	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2568
		2569	=item L<Time::HiRes>
		2570
		2571	This module is part of perl since release 5.008. It will be used when the
		2572	chosen event library does not come with a timing source on it's own. The
		2573	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2574	try to use a monotonic clock for timing stability.
		2575
		2576	=back
		2577
		2578
2066	=head1 FORK	2579	=head1 FORK
2067		2580
2068	Most event libraries are not fork-safe. The ones who are usually are	2581	Most event libraries are not fork-safe. The ones who are usually are
2069	because they rely on inefficient but fork-safe C<select> or C<poll>	2582	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2070	calls. Only L<EV> is fully fork-aware.	2583	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2584	are usually badly thought-out hacks that are incompatible with fork in
		2585	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2586	continue event-processing in both parent and child (or both, if you know
		2587	what you are doing).
		2588
		2589	This means that, in general, you cannot fork and do event processing in
		2590	the child if the event library was initialised before the fork (which
		2591	usually happens when the first AnyEvent watcher is created, or the library
		2592	is loaded).
2071		2593
2072	If you have to fork, you must either do so I<before> creating your first	2594	If you have to fork, you must either do so I<before> creating your first
2073	watcher OR you must not use AnyEvent at all in the child.	2595	watcher OR you must not use AnyEvent at all in the child OR you must do
		2596	something completely out of the scope of AnyEvent.
		2597
		2598	The problem of doing event processing in the parent I<and> the child
		2599	is much more complicated: even for backends that I<are> fork-aware or
		2600	fork-safe, their behaviour is not usually what you want: fork clones all
		2601	watchers, that means all timers, I/O watchers etc. are active in both
		2602	parent and child, which is almost never what you want. USing C<exec>
		2603	to start worker children from some kind of manage rprocess is usually
		2604	preferred, because it is much easier and cleaner, at the expense of having
		2605	to have another binary.
2074		2606
2075		2607
2076	=head1 SECURITY CONSIDERATIONS	2608	=head1 SECURITY CONSIDERATIONS
2077		2609
2078	AnyEvent can be forced to load any event model via	2610	AnyEvent can be forced to load any event model via
…		…
2116	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2648	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2117		2649
2118	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2650	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2119	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2651	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2120	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2652	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2121	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.	2653	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2122		2654
2123	Non-blocking file handles, sockets, TCP clients and	2655	Non-blocking file handles, sockets, TCP clients and
2124	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2656	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2125		2657
2126	Asynchronous DNS: L<AnyEvent::DNS>.	2658	Asynchronous DNS: L<AnyEvent::DNS>.

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