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Revision 1.327 by root, Sun Jun 6 10:13:57 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
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
12	# file descriptor readable	15	# file handle or descriptor readable
13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14		17
15	# one-shot or repeating timers	18	# one-shot or repeating timers
16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
…		…
40	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
41		44
42	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
43	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
		48
		49	=head1 SUPPORT
		50
		51	There is a mailinglist for discussing all things AnyEvent, and an IRC
		52	channel, too.
		53
		54	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		55	Repository>, at L<http://anyevent.schmorp.de>, for more info.
45		56
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	57	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		58
48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	59	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49	nowadays. So what is different about AnyEvent?	60	nowadays. So what is different about AnyEvent?
…		…
173	my variables are only visible after the statement in which they are	184	my variables are only visible after the statement in which they are
174	declared.	185	declared.
175		186
176	=head2 I/O WATCHERS	187	=head2 I/O WATCHERS
177		188
		189	$w = AnyEvent->io (
		190	fh => <filehandle_or_fileno>,
		191	poll => <"r" or "w">,
		192	cb => <callback>,
		193	);
		194
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	195	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	196	with the following mandatory key-value pairs as arguments:
180		197
181	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch	198	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	199	for events (AnyEvent might or might not keep a reference to this file
…		…
211	undef $w;	228	undef $w;
212	});	229	});
213		230
214	=head2 TIME WATCHERS	231	=head2 TIME WATCHERS
215		232
		233	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		234
		235	$w = AnyEvent->timer (
		236	after => <fractional_seconds>,
		237	interval => <fractional_seconds>,
		238	cb => <callback>,
		239	);
		240
216	You can create a time watcher by calling the C<< AnyEvent->timer >>	241	You can create a time watcher by calling the C<< AnyEvent->timer >>
217	method with the following mandatory arguments:	242	method with the following mandatory arguments:
218		243
219	C<after> specifies after how many seconds (fractional values are	244	C<after> specifies after how many seconds (fractional values are
220	supported) the callback should be invoked. C<cb> is the callback to invoke	245	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
341	might affect timers and time-outs.	366	might affect timers and time-outs.
342		367
343	When this is the case, you can call this method, which will update the	368	When this is the case, you can call this method, which will update the
344	event loop's idea of "current time".	369	event loop's idea of "current time".
345		370
		371	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		372	when mod_perl executes the script, then the event loop will have the wrong
		373	idea about the "current time" (being potentially far in the past, when the
		374	script ran the last time). In that case you should arrange a call to C<<
		375	AnyEvent->now_update >> each time the web server process wakes up again
		376	(e.g. at the start of your script, or in a handler).
		377
346	Note that updating the time I<might> cause some events to be handled.	378	Note that updating the time I<might> cause some events to be handled.
347		379
348	=back	380	=back
349		381
350	=head2 SIGNAL WATCHERS	382	=head2 SIGNAL WATCHERS
		383
		384	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351		385
352	You can watch for signals using a signal watcher, C<signal> is the signal	386	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	387	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354	callback to be invoked whenever a signal occurs.	388	callback to be invoked whenever a signal occurs.
355		389
…		…
368		402
369	This watcher might use C<%SIG> (depending on the event loop used),	403	This watcher might use C<%SIG> (depending on the event loop used),
370	so programs overwriting those signals directly will likely not work	404	so programs overwriting those signals directly will likely not work
371	correctly.	405	correctly.
372		406
		407	Example: exit on SIGINT
		408
		409	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
		410
		411	=head3 Restart Behaviour
		412
		413	While restart behaviour is up to the event loop implementation, most will
		414	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		415	pure perl implementation).
		416
		417	=head3 Safe/Unsafe Signals
		418
		419	Perl signals can be either "safe" (synchronous to opcode handling) or
		420	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		421	latter might corrupt your memory.
		422
		423	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		424	i.e. they will not interrupt your running perl program but will only be
		425	called as part of the normal event handling (just like timer, I/O etc.
		426	callbacks, too).
		427
		428	=head3 Signal Races, Delays and Workarounds
		429
373	Also note that many event loops (e.g. Glib, Tk, Qt, IO::Async) do not	430	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
374	support attaching callbacks to signals, which is a pity, as you cannot do	431	callbacks to signals in a generic way, which is a pity, as you cannot
375	race-free signal handling in perl. AnyEvent will try to do it's best, but	432	do race-free signal handling in perl, requiring C libraries for
		433	this. AnyEvent will try to do it's best, which means in some cases,
376	in some cases, signals will be delayed. The maximum time a signal might	434	signals will be delayed. The maximum time a signal might be delayed is
377	be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10	435	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
378	seconds). This variable can be changed only before the first signal	436	variable can be changed only before the first signal watcher is created,
379	watcher is created, and should be left alone otherwise. Higher values	437	and should be left alone otherwise. This variable determines how often
		438	AnyEvent polls for signals (in case a wake-up was missed). Higher values
380	will cause fewer spurious wake-ups, which is better for power and CPU	439	will cause fewer spurious wake-ups, which is better for power and CPU
		440	saving.
		441
381	saving. All these problems can be avoided by installing the optional	442	All these problems can be avoided by installing the optional
382	L<Async::Interrupt> module.	443	L<Async::Interrupt> module, which works with most event loops. It will not
383		444	work with inherently broken event loops such as L<Event> or L<Event::Lib>
384	Example: exit on SIGINT	445	(and not with L<POE> currently, as POE does it's own workaround with
385		446	one-second latency). For those, you just have to suffer the delays.
386	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
387		447
388	=head2 CHILD PROCESS WATCHERS	448	=head2 CHILD PROCESS WATCHERS
389		449
		450	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		451
390	You can also watch on a child process exit and catch its exit status.	452	You can also watch on a child process exit and catch its exit status.
391		453
392	The child process is specified by the C<pid> argument (if set to C<0>, it	454	The child process is specified by the C<pid> argument (one some backends,
393	watches for any child process exit). The watcher will triggered only when	455	using C<0> watches for any child process exit, on others this will
394	the child process has finished and an exit status is available, not on	456	croak). The watcher will be triggered only when the child process has
395	any trace events (stopped/continued).	457	finished and an exit status is available, not on any trace events
		458	(stopped/continued).
396		459
397	The callback will be called with the pid and exit status (as returned by	460	The callback will be called with the pid and exit status (as returned by
398	waitpid), so unlike other watcher types, you I<can> rely on child watcher	461	waitpid), so unlike other watcher types, you I<can> rely on child watcher
399	callback arguments.	462	callback arguments.
400		463
…		…
441	# do something else, then wait for process exit	504	# do something else, then wait for process exit
442	$done->recv;	505	$done->recv;
443		506
444	=head2 IDLE WATCHERS	507	=head2 IDLE WATCHERS
445		508
446	Sometimes there is a need to do something, but it is not so important	509	$w = AnyEvent->idle (cb => <callback>);
447	to do it instantly, but only when there is nothing better to do. This
448	"nothing better to do" is usually defined to be "no other events need
449	attention by the event loop".
450		510
451	Idle watchers ideally get invoked when the event loop has nothing	511	Repeatedly invoke the callback after the process becomes idle, until
452	better to do, just before it would block the process to wait for new	512	either the watcher is destroyed or new events have been detected.
453	events. Instead of blocking, the idle watcher is invoked.
454		513
455	Most event loops unfortunately do not really support idle watchers (only	514	Idle watchers are useful when there is a need to do something, but it
		515	is not so important (or wise) to do it instantly. The callback will be
		516	invoked only when there is "nothing better to do", which is usually
		517	defined as "all outstanding events have been handled and no new events
		518	have been detected". That means that idle watchers ideally get invoked
		519	when the event loop has just polled for new events but none have been
		520	detected. Instead of blocking to wait for more events, the idle watchers
		521	will be invoked.
		522
		523	Unfortunately, most event loops do not really support idle watchers (only
456	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	524	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
457	will simply call the callback "from time to time".	525	will simply call the callback "from time to time".
458		526
459	Example: read lines from STDIN, but only process them when the	527	Example: read lines from STDIN, but only process them when the
460	program is otherwise idle:	528	program is otherwise idle:
…		…
476	});	544	});
477	});	545	});
478		546
479	=head2 CONDITION VARIABLES	547	=head2 CONDITION VARIABLES
480		548
		549	$cv = AnyEvent->condvar;
		550
		551	$cv->send (<list>);
		552	my @res = $cv->recv;
		553
481	If you are familiar with some event loops you will know that all of them	554	If you are familiar with some event loops you will know that all of them
482	require you to run some blocking "loop", "run" or similar function that	555	require you to run some blocking "loop", "run" or similar function that
483	will actively watch for new events and call your callbacks.	556	will actively watch for new events and call your callbacks.
484		557
485	AnyEvent is slightly different: it expects somebody else to run the event	558	AnyEvent is slightly different: it expects somebody else to run the event
486	loop and will only block when necessary (usually when told by the user).	559	loop and will only block when necessary (usually when told by the user).
487		560
488	The instrument to do that is called a "condition variable", so called	561	The tool to do that is called a "condition variable", so called because
489	because they represent a condition that must become true.	562	they represent a condition that must become true.
490		563
491	Now is probably a good time to look at the examples further below.	564	Now is probably a good time to look at the examples further below.
492		565
493	Condition variables can be created by calling the C<< AnyEvent->condvar	566	Condition variables can be created by calling the C<< AnyEvent->condvar
494	>> method, usually without arguments. The only argument pair allowed is	567	>> method, usually without arguments. The only argument pair allowed is
…		…
499	After creation, the condition variable is "false" until it becomes "true"	572	After creation, the condition variable is "false" until it becomes "true"
500	by calling the C<send> method (or calling the condition variable as if it	573	by calling the C<send> method (or calling the condition variable as if it
501	were a callback, read about the caveats in the description for the C<<	574	were a callback, read about the caveats in the description for the C<<
502	->send >> method).	575	->send >> method).
503		576
504	Condition variables are similar to callbacks, except that you can	577	Since condition variables are the most complex part of the AnyEvent API, here are
505	optionally wait for them. They can also be called merge points - points	578	some different mental models of what they are - pick the ones you can connect to:
506	in time where multiple outstanding events have been processed. And yet	579
507	another way to call them is transactions - each condition variable can be	580	=over 4
508	used to represent a transaction, which finishes at some point and delivers	581
509	a result.	582	=item * Condition variables are like callbacks - you can call them (and pass them instead
		583	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		584
		585	=item * Condition variables are signals - one side can emit or send them,
		586	the other side can wait for them, or install a handler that is called when
		587	the signal fires.
		588
		589	=item * Condition variables are like "Merge Points" - points in your program
		590	where you merge multiple independent results/control flows into one.
		591
		592	=item * Condition variables represent a transaction - function that start
		593	some kind of transaction can return them, leaving the caller the choice
		594	between waiting in a blocking fashion, or setting a callback.
		595
		596	=item * Condition variables represent future values, or promises to deliver
		597	some result, long before the result is available.
		598
		599	=back
510		600
511	Condition variables are very useful to signal that something has finished,	601	Condition variables are very useful to signal that something has finished,
512	for example, if you write a module that does asynchronous http requests,	602	for example, if you write a module that does asynchronous http requests,
513	then a condition variable would be the ideal candidate to signal the	603	then a condition variable would be the ideal candidate to signal the
514	availability of results. The user can either act when the callback is	604	availability of results. The user can either act when the callback is
…		…
535	eventually calls C<< -> send >>, and the "consumer side", which waits	625	eventually calls C<< -> send >>, and the "consumer side", which waits
536	for the send to occur.	626	for the send to occur.
537		627
538	Example: wait for a timer.	628	Example: wait for a timer.
539		629
540	# wait till the result is ready	630	# condition: "wait till the timer is fired"
541	my $result_ready = AnyEvent->condvar;	631	my $timer_fired = AnyEvent->condvar;
542		632
543	# do something such as adding a timer	633	# create the timer - we could wait for, say
544	# or socket watcher the calls $result_ready->send	634	# a handle becomign ready, or even an
545	# when the "result" is ready.	635	# AnyEvent::HTTP request to finish, but
546	# in this case, we simply use a timer:	636	# in this case, we simply use a timer:
547	my $w = AnyEvent->timer (	637	my $w = AnyEvent->timer (
548	after => 1,	638	after => 1,
549	cb => sub { $result_ready->send },	639	cb => sub { $timer_fired->send },
550	);	640	);
551		641
552	# this "blocks" (while handling events) till the callback	642	# this "blocks" (while handling events) till the callback
553	# calls -<send	643	# calls ->send
554	$result_ready->recv;	644	$timer_fired->recv;
555		645
556	Example: wait for a timer, but take advantage of the fact that condition	646	Example: wait for a timer, but take advantage of the fact that condition
557	variables are also callable directly.	647	variables are also callable directly.
558		648
559	my $done = AnyEvent->condvar;	649	my $done = AnyEvent->condvar;
…		…
622	one. For example, a function that pings many hosts in parallel might want	712	one. For example, a function that pings many hosts in parallel might want
623	to use a condition variable for the whole process.	713	to use a condition variable for the whole process.
624		714
625	Every call to C<< ->begin >> will increment a counter, and every call to	715	Every call to C<< ->begin >> will increment a counter, and every call to
626	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	716	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
627	>>, the (last) callback passed to C<begin> will be executed. That callback	717	>>, the (last) callback passed to C<begin> will be executed, passing the
628	is I<supposed> to call C<< ->send >>, but that is not required. If no	718	condvar as first argument. That callback is I<supposed> to call C<< ->send
629	callback was set, C<send> will be called without any arguments.	719	>>, but that is not required. If no group callback was set, C<send> will
		720	be called without any arguments.
630		721
631	You can think of C<< $cv->send >> giving you an OR condition (one call	722	You can think of C<< $cv->send >> giving you an OR condition (one call
632	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND	723	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
633	condition (all C<begin> calls must be C<end>'ed before the condvar sends).	724	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
634		725
…		…
661	begung can potentially be zero:	752	begung can potentially be zero:
662		753
663	my $cv = AnyEvent->condvar;	754	my $cv = AnyEvent->condvar;
664		755
665	my %result;	756	my %result;
666	$cv->begin (sub { $cv->send (\%result) });	757	$cv->begin (sub { shift->send (\%result) });
667		758
668	for my $host (@list_of_hosts) {	759	for my $host (@list_of_hosts) {
669	$cv->begin;	760	$cv->begin;
670	ping_host_then_call_callback $host, sub {	761	ping_host_then_call_callback $host, sub {
671	$result{$host} = ...;	762	$result{$host} = ...;
…		…
746	=item $cb = $cv->cb ($cb->($cv))	837	=item $cb = $cv->cb ($cb->($cv))
747		838
748	This is a mutator function that returns the callback set and optionally	839	This is a mutator function that returns the callback set and optionally
749	replaces it before doing so.	840	replaces it before doing so.
750		841
751	The callback will be called when the condition becomes "true", i.e. when	842	The callback will be called when the condition becomes (or already was)
752	C<send> or C<croak> are called, with the only argument being the condition	843	"true", i.e. when C<send> or C<croak> are called (or were called), with
753	variable itself. Calling C<recv> inside the callback or at any later time	844	the only argument being the condition variable itself. Calling C<recv>
754	is guaranteed not to block.	845	inside the callback or at any later time is guaranteed not to block.
755		846
756	=back	847	=back
757		848
758	=head1 SUPPORTED EVENT LOOPS/BACKENDS	849	=head1 SUPPORTED EVENT LOOPS/BACKENDS
759		850
…		…
762	=over 4	853	=over 4
763		854
764	=item Backends that are autoprobed when no other event loop can be found.	855	=item Backends that are autoprobed when no other event loop can be found.
765		856
766	EV is the preferred backend when no other event loop seems to be in	857	EV is the preferred backend when no other event loop seems to be in
767	use. If EV is not installed, then AnyEvent will try Event, and, failing	858	use. If EV is not installed, then AnyEvent will fall back to its own
768	that, will fall back to its own pure-perl implementation, which is	859	pure-perl implementation, which is available everywhere as it comes with
769	available everywhere as it comes with AnyEvent itself.	860	AnyEvent itself.
770		861
771	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	862	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
772	AnyEvent::Impl::Event based on Event, very stable, few glitches.
773	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	863	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
774		864
775	=item Backends that are transparently being picked up when they are used.	865	=item Backends that are transparently being picked up when they are used.
776		866
777	These will be used when they are currently loaded when the first watcher	867	These will be used when they are currently loaded when the first watcher
778	is created, in which case it is assumed that the application is using	868	is created, in which case it is assumed that the application is using
779	them. This means that AnyEvent will automatically pick the right backend	869	them. This means that AnyEvent will automatically pick the right backend
780	when the main program loads an event module before anything starts to	870	when the main program loads an event module before anything starts to
781	create watchers. Nothing special needs to be done by the main program.	871	create watchers. Nothing special needs to be done by the main program.
782		872
		873	AnyEvent::Impl::Event based on Event, very stable, few glitches.
783	AnyEvent::Impl::Glib based on Glib, slow but very stable.	874	AnyEvent::Impl::Glib based on Glib, slow but very stable.
784	AnyEvent::Impl::Tk based on Tk, very broken.	875	AnyEvent::Impl::Tk based on Tk, very broken.
785	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	876	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
786	AnyEvent::Impl::POE based on POE, very slow, some limitations.	877	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		878	AnyEvent::Impl::Irssi used when running within irssi.
787		879
788	=item Backends with special needs.	880	=item Backends with special needs.
789		881
790	Qt requires the Qt::Application to be instantiated first, but will	882	Qt requires the Qt::Application to be instantiated first, but will
791	otherwise be picked up automatically. As long as the main program	883	otherwise be picked up automatically. As long as the main program
…		…
865	event module detection too early, for example, L<AnyEvent::AIO> creates	957	event module detection too early, for example, L<AnyEvent::AIO> creates
866	and installs the global L<IO::AIO> watcher in a C<post_detect> block to	958	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
867	avoid autodetecting the event module at load time.	959	avoid autodetecting the event module at load time.
868		960
869	If called in scalar or list context, then it creates and returns an object	961	If called in scalar or list context, then it creates and returns an object
870	that automatically removes the callback again when it is destroyed. See	962	that automatically removes the callback again when it is destroyed (or
		963	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
871	L<Coro::BDB> for a case where this is useful.	964	a case where this is useful.
		965
		966	Example: Create a watcher for the IO::AIO module and store it in
		967	C<$WATCHER>. Only do so after the event loop is initialised, though.
		968
		969	our WATCHER;
		970
		971	my $guard = AnyEvent::post_detect {
		972	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		973	};
		974
		975	# the ||= is important in case post_detect immediately runs the block,
		976	# as to not clobber the newly-created watcher. assigning both watcher and
		977	# post_detect guard to the same variable has the advantage of users being
		978	# able to just C<undef $WATCHER> if the watcher causes them grief.
		979
		980	$WATCHER ||= $guard;
872		981
873	=item @AnyEvent::post_detect	982	=item @AnyEvent::post_detect
874		983
875	If there are any code references in this array (you can C<push> to it	984	If there are any code references in this array (you can C<push> to it
876	before or after loading AnyEvent), then they will called directly after	985	before or after loading AnyEvent), then they will called directly after
…		…
879	You should check C<$AnyEvent::MODEL> before adding to this array, though:	988	You should check C<$AnyEvent::MODEL> before adding to this array, though:
880	if it is defined then the event loop has already been detected, and the	989	if it is defined then the event loop has already been detected, and the
881	array will be ignored.	990	array will be ignored.
882		991
883	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	992	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
884	it,as it takes care of these details.	993	it, as it takes care of these details.
885		994
886	This variable is mainly useful for modules that can do something useful	995	This variable is mainly useful for modules that can do something useful
887	when AnyEvent is used and thus want to know when it is initialised, but do	996	when AnyEvent is used and thus want to know when it is initialised, but do
888	not need to even load it by default. This array provides the means to hook	997	not need to even load it by default. This array provides the means to hook
889	into AnyEvent passively, without loading it.	998	into AnyEvent passively, without loading it.
		999
		1000	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1001	together, you could put this into Coro (this is the actual code used by
		1002	Coro to accomplish this):
		1003
		1004	if (defined $AnyEvent::MODEL) {
		1005	# AnyEvent already initialised, so load Coro::AnyEvent
		1006	require Coro::AnyEvent;
		1007	} else {
		1008	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1009	# as soon as it is
		1010	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1011	}
890		1012
891	=back	1013	=back
892		1014
893	=head1 WHAT TO DO IN A MODULE	1015	=head1 WHAT TO DO IN A MODULE
894		1016
…		…
951	=head1 OTHER MODULES	1073	=head1 OTHER MODULES
952		1074
953	The following is a non-exhaustive list of additional modules that use	1075	The following is a non-exhaustive list of additional modules that use
954	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1076	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
955	modules and other event loops in the same program. Some of the modules	1077	modules and other event loops in the same program. Some of the modules
956	come with AnyEvent, most are available via CPAN.	1078	come as part of AnyEvent, the others are available via CPAN.
957		1079
958	=over 4	1080	=over 4
959		1081
960	=item L<AnyEvent::Util>	1082	=item L<AnyEvent::Util>
961		1083
…		…
976		1098
977	=item L<AnyEvent::DNS>	1099	=item L<AnyEvent::DNS>
978		1100
979	Provides rich asynchronous DNS resolver capabilities.	1101	Provides rich asynchronous DNS resolver capabilities.
980		1102
		1103	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1104
		1105	Implement event-based interfaces to the protocols of the same name (for
		1106	the curious, IGS is the International Go Server and FCP is the Freenet
		1107	Client Protocol).
		1108
		1109	=item L<AnyEvent::Handle::UDP>
		1110
		1111	Here be danger!
		1112
		1113	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1114	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1115	it's use of a stream-based API with a protocol that isn't streamable, that
		1116	the only way to improve it is to delete it.
		1117
		1118	It features data corruption (but typically only under load) and general
		1119	confusion. On top, the author is not only clueless about UDP but also
		1120	fact-resistant - some gems of his understanding: "connect doesn't work
		1121	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1122	packets", "I don't need to implement proper error checking as UDP doesn't
		1123	support error checking" and so on - he doesn't even understand what's
		1124	wrong with his module when it is explained to him.
		1125
981	=item L<AnyEvent::HTTP>	1126	=item L<AnyEvent::DBI>
982		1127
983	A simple-to-use HTTP library that is capable of making a lot of concurrent	1128	Executes L<DBI> requests asynchronously in a proxy process for you,
984	HTTP requests.	1129	notifying you in an event-bnased way when the operation is finished.
		1130
		1131	=item L<AnyEvent::AIO>
		1132
		1133	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1134	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1135	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1136	file I/O, and much more.
985		1137
986	=item L<AnyEvent::HTTPD>	1138	=item L<AnyEvent::HTTPD>
987		1139
988	Provides a simple web application server framework.	1140	A simple embedded webserver.
989		1141
990	=item L<AnyEvent::FastPing>	1142	=item L<AnyEvent::FastPing>
991		1143
992	The fastest ping in the west.	1144	The fastest ping in the west.
993
994	=item L<AnyEvent::DBI>
995
996	Executes L<DBI> requests asynchronously in a proxy process.
997
998	=item L<AnyEvent::AIO>
999
1000	Truly asynchronous I/O, should be in the toolbox of every event
1001	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1002	together.
1003
1004	=item L<AnyEvent::BDB>
1005
1006	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1007	L<BDB> and AnyEvent together.
1008
1009	=item L<AnyEvent::GPSD>
1010
1011	A non-blocking interface to gpsd, a daemon delivering GPS information.
1012
1013	=item L<AnyEvent::IRC>
1014
1015	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1016
1017	=item L<AnyEvent::XMPP>
1018
1019	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1020	Net::XMPP2>.
1021
1022	=item L<AnyEvent::IGS>
1023
1024	A non-blocking interface to the Internet Go Server protocol (used by
1025	L<App::IGS>).
1026
1027	=item L<Net::FCP>
1028
1029	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1030	of AnyEvent.
1031
1032	=item L<Event::ExecFlow>
1033
1034	High level API for event-based execution flow control.
1035		1145
1036	=item L<Coro>	1146	=item L<Coro>
1037		1147
1038	Has special support for AnyEvent via L<Coro::AnyEvent>.	1148	Has special support for AnyEvent via L<Coro::AnyEvent>.
1039		1149
…		…
1043		1153
1044	package AnyEvent;	1154	package AnyEvent;
1045		1155
1046	# basically a tuned-down version of common::sense	1156	# basically a tuned-down version of common::sense
1047	sub common_sense {	1157	sub common_sense {
1048	# no warnings	1158	# from common:.sense 1.0
1049	${^WARNING_BITS} ^= ${^WARNING_BITS};	1159	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
1050	# use strict vars subs	1160	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1051	$^H |= 0x00000600;	1161	$^H |= 0x00000600;
1052	}	1162	}
1053		1163
1054	BEGIN { AnyEvent::common_sense }	1164	BEGIN { AnyEvent::common_sense }
1055		1165
1056	use Carp ();	1166	use Carp ();
1057		1167
1058	our $VERSION = 4.83;	1168	our $VERSION = '5.27';
1059	our $MODEL;	1169	our $MODEL;
1060		1170
1061	our $AUTOLOAD;	1171	our $AUTOLOAD;
1062	our @ISA;	1172	our @ISA;
1063		1173
1064	our @REGISTRY;	1174	our @REGISTRY;
1065		1175
1066	our $WIN32;
1067
1068	our $VERBOSE;	1176	our $VERBOSE;
1069		1177
1070	BEGIN {	1178	BEGIN {
1071	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1179	require "AnyEvent/constants.pl";
		1180
1072	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1181	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1073		1182
1074	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1183	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1075	if ${^TAINT};	1184	if ${^TAINT};
1076		1185
1077	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1186	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
…		…
1088	for reverse split /\s*,\s*/,	1197	for reverse split /\s*,\s*/,
1089	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1198	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1090	}	1199	}
1091		1200
1092	my @models = (	1201	my @models = (
1093	[EV:: => AnyEvent::Impl::EV::],	1202	[EV:: => AnyEvent::Impl::EV:: , 1],
1094	[Event:: => AnyEvent::Impl::Event::],
1095	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1203	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1096	# everything below here will not be autoprobed	1204	# everything below here will not (normally) be autoprobed
1097	# as the pureperl backend should work everywhere	1205	# as the pureperl backend should work everywhere
1098	# and is usually faster	1206	# and is usually faster
		1207	[Event:: => AnyEvent::Impl::Event::, 1],
1099	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1208	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1100	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1209	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1210	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1101	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1211	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1102	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1212	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1103	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1213	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1104	[Wx:: => AnyEvent::Impl::POE::],	1214	[Wx:: => AnyEvent::Impl::POE::],
1105	[Prima:: => AnyEvent::Impl::POE::],	1215	[Prima:: => AnyEvent::Impl::POE::],
1106	# IO::Async is just too broken - we would need workarounds for its	1216	# IO::Async is just too broken - we would need workarounds for its
1107	# byzantine signal and broken child handling, among others.	1217	# byzantine signal and broken child handling, among others.
1108	# IO::Async is rather hard to detect, as it doesn't have any	1218	# IO::Async is rather hard to detect, as it doesn't have any
1109	# obvious default class.	1219	# obvious default class.
1110	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program	1220	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1111	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program	1221	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1112	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program	1222	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1223	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1113	);	1224	);
1114		1225
1115	our %method = map +($_ => 1),	1226	our %method = map +($_ => 1),
1116	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1227	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
1117		1228
1118	our @post_detect;	1229	our @post_detect;
1119		1230
1120	sub post_detect(&) {	1231	sub post_detect(&) {
1121	my ($cb) = @_;	1232	my ($cb) = @_;
1122		1233
1123	if ($MODEL) {
1124	$cb->();
1125
1126	1
1127	} else {
1128	push @post_detect, $cb;	1234	push @post_detect, $cb;
1129		1235
1130	defined wantarray	1236	defined wantarray
1131	? bless \$cb, "AnyEvent::Util::postdetect"	1237	? bless \$cb, "AnyEvent::Util::postdetect"
1132	: ()	1238	: ()
1133	}
1134	}	1239	}
1135		1240
1136	sub AnyEvent::Util::postdetect::DESTROY {	1241	sub AnyEvent::Util::postdetect::DESTROY {
1137	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1242	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1138	}	1243	}
1139		1244
1140	sub detect() {	1245	sub detect() {
		1246	# free some memory
		1247	*detect = sub () { $MODEL };
		1248
		1249	local $!; # for good measure
		1250	local $SIG{__DIE__};
		1251
		1252	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1253	my $model = "AnyEvent::Impl::$1";
		1254	if (eval "require $model") {
		1255	$MODEL = $model;
		1256	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1257	} else {
		1258	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1259	}
		1260	}
		1261
		1262	# check for already loaded models
1141	unless ($MODEL) {	1263	unless ($MODEL) {
1142	local $SIG{__DIE__};	1264	for (@REGISTRY, @models) {
1143		1265	my ($package, $model) = @$_;
1144	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1266	if (${"$package\::VERSION"} > 0) {
1145	my $model = "AnyEvent::Impl::$1";
1146	if (eval "require $model") {	1267	if (eval "require $model") {
1147	$MODEL = $model;	1268	$MODEL = $model;
1148	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1269	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1149	} else {	1270	last;
1150	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1271	}
1151	}	1272	}
1152	}	1273	}
1153		1274
1154	# check for already loaded models
1155	unless ($MODEL) {	1275	unless ($MODEL) {
		1276	# try to autoload a model
1156	for (@REGISTRY, @models) {	1277	for (@REGISTRY, @models) {
1157	my ($package, $model) = @$_;	1278	my ($package, $model, $autoload) = @$_;
		1279	if (
		1280	$autoload
		1281	and eval "require $package"
1158	if (${"$package\::VERSION"} > 0) {	1282	and ${"$package\::VERSION"} > 0
1159	if (eval "require $model") {	1283	and eval "require $model"
		1284	) {
1160	$MODEL = $model;	1285	$MODEL = $model;
1161	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;	1286	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1162	last;	1287	last;
1163	}
1164	}	1288	}
1165	}	1289	}
1166		1290
1167	unless ($MODEL) {
1168	# try to load a model
1169
1170	for (@REGISTRY, @models) {
1171	my ($package, $model) = @$_;
1172	if (eval "require $package"
1173	and ${"$package\::VERSION"} > 0
1174	and eval "require $model") {
1175	$MODEL = $model;
1176	warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1177	last;
1178	}
1179	}
1180
1181	$MODEL	1291	$MODEL
1182	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1292	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
1183	}
1184	}	1293	}
1185
1186	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1187
1188	unshift @ISA, $MODEL;
1189
1190	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1191
1192	(shift @post_detect)->() while @post_detect;
1193	}	1294	}
		1295
		1296	@models = (); # free probe data
		1297
		1298	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1299	unshift @ISA, $MODEL;
		1300
		1301	# now nuke some methods that are overriden by the backend.
		1302	# SUPER is not allowed.
		1303	for (qw(time signal child idle)) {
		1304	undef &{"AnyEvent::Base::$_"}
		1305	if defined &{"$MODEL\::$_"};
		1306	}
		1307
		1308	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1309
		1310	(shift @post_detect)->() while @post_detect;
		1311
		1312	*post_detect = sub(&) {
		1313	shift->();
		1314
		1315	undef
		1316	};
1194		1317
1195	$MODEL	1318	$MODEL
1196	}	1319	}
1197		1320
1198	sub AUTOLOAD {	1321	sub AUTOLOAD {
1199	(my $func = $AUTOLOAD) =~ s/.*://;	1322	(my $func = $AUTOLOAD) =~ s/.*://;
1200		1323
1201	$method{$func}	1324	$method{$func}
1202	or Carp::croak "$func: not a valid method for AnyEvent objects";	1325	or Carp::croak "$func: not a valid AnyEvent class method";
1203		1326
1204	detect unless $MODEL;	1327	detect;
1205		1328
1206	my $class = shift;	1329	my $class = shift;
1207	$class->$func (@_);	1330	$class->$func (@_);
1208	}	1331	}
1209		1332
…		…
1222	# we assume CLOEXEC is already set by perl in all important cases	1345	# we assume CLOEXEC is already set by perl in all important cases
1223		1346
1224	($fh2, $rw)	1347	($fh2, $rw)
1225	}	1348	}
1226		1349
		1350	=head1 SIMPLIFIED AE API
		1351
		1352	Starting with version 5.0, AnyEvent officially supports a second, much
		1353	simpler, API that is designed to reduce the calling, typing and memory
		1354	overhead by using function call syntax and a fixed number of parameters.
		1355
		1356	See the L<AE> manpage for details.
		1357
		1358	=cut
		1359
		1360	package AE;
		1361
		1362	our $VERSION = $AnyEvent::VERSION;
		1363
		1364	# fall back to the main API by default - backends and AnyEvent::Base
		1365	# implementations can overwrite these.
		1366
		1367	sub io($$$) {
		1368	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1369	}
		1370
		1371	sub timer($$$) {
		1372	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1373	}
		1374
		1375	sub signal($$) {
		1376	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1377	}
		1378
		1379	sub child($$) {
		1380	AnyEvent->child (pid => $_[0], cb => $_[1])
		1381	}
		1382
		1383	sub idle($) {
		1384	AnyEvent->idle (cb => $_[0])
		1385	}
		1386
		1387	sub cv(;&) {
		1388	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1389	}
		1390
		1391	sub now() {
		1392	AnyEvent->now
		1393	}
		1394
		1395	sub now_update() {
		1396	AnyEvent->now_update
		1397	}
		1398
		1399	sub time() {
		1400	AnyEvent->time
		1401	}
		1402
1227	package AnyEvent::Base;	1403	package AnyEvent::Base;
1228		1404
1229	# default implementations for many methods	1405	# default implementations for many methods
1230		1406
1231	sub _time {	1407	sub time {
		1408	eval q{ # poor man's autoloading {}
1232	# probe for availability of Time::HiRes	1409	# probe for availability of Time::HiRes
1233	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1410	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1234	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1411	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1235	*_time = \&Time::HiRes::time;	1412	*AE::time = \&Time::HiRes::time;
1236	# if (eval "use POSIX (); (POSIX::times())...	1413	# if (eval "use POSIX (); (POSIX::times())...
1237	} else {	1414	} else {
1238	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1415	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1239	*_time = sub { time }; # epic fail	1416	*AE::time = sub (){ time }; # epic fail
		1417	}
		1418
		1419	*time = sub { AE::time }; # different prototypes
1240	}	1420	};
		1421	die if $@;
1241		1422
1242	&_time	1423	&time
1243	}	1424	}
1244		1425
1245	sub time { _time }	1426	*now = \&time;
1246	sub now { _time }	1427
1247	sub now_update { }	1428	sub now_update { }
1248		1429
1249	# default implementation for ->condvar	1430	# default implementation for ->condvar
1250		1431
1251	sub condvar {	1432	sub condvar {
		1433	eval q{ # poor man's autoloading {}
		1434	*condvar = sub {
1252	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1435	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1436	};
		1437
		1438	*AE::cv = sub (;&) {
		1439	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1440	};
		1441	};
		1442	die if $@;
		1443
		1444	&condvar
1253	}	1445	}
1254		1446
1255	# default implementation for ->signal	1447	# default implementation for ->signal
1256		1448
1257	our $HAVE_ASYNC_INTERRUPT;	1449	our $HAVE_ASYNC_INTERRUPT;
		1450
		1451	sub _have_async_interrupt() {
		1452	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1453	&& eval "use Async::Interrupt 1.02 (); 1")
		1454	unless defined $HAVE_ASYNC_INTERRUPT;
		1455
		1456	$HAVE_ASYNC_INTERRUPT
		1457	}
		1458
1258	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1459	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1259	our (%SIG_ASY, %SIG_ASY_W);	1460	our (%SIG_ASY, %SIG_ASY_W);
1260	our ($SIG_COUNT, $SIG_TW);	1461	our ($SIG_COUNT, $SIG_TW);
1261		1462
1262	sub _signal_exec {	1463	# install a dummy wakeup watcher to reduce signal catching latency
1263	$HAVE_ASYNC_INTERRUPT	1464	# used by Impls
1264	? $SIGPIPE_R->drain	1465	sub _sig_add() {
1265	: sysread $SIGPIPE_R, my $dummy, 9;	1466	unless ($SIG_COUNT++) {
		1467	# try to align timer on a full-second boundary, if possible
		1468	my $NOW = AE::now;
1266		1469
1267	while (%SIG_EV) {	1470	$SIG_TW = AE::timer
1268	for (keys %SIG_EV) {	1471	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1269	delete $SIG_EV{$_};	1472	$MAX_SIGNAL_LATENCY,
1270	$_->() for values %{ $SIG_CB{$_} || {} };	1473	sub { } # just for the PERL_ASYNC_CHECK
1271	}	1474	;
1272	}	1475	}
1273	}	1476	}
1274		1477
1275	sub _signal {	1478	sub _sig_del {
1276	my (undef, %arg) = @_;
1277
1278	my $signal = uc $arg{signal}
1279	or Carp::croak "required option 'signal' is missing";
1280
1281	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1282
1283	if ($HAVE_ASYNC_INTERRUPT) {
1284	# async::interrupt
1285
1286	$SIG_ASY{$signal} ||= do {
1287	my $asy = new Async::Interrupt
1288	cb => sub { undef $SIG_EV{$signal} },
1289	signal => $signal,
1290	pipe => [$SIGPIPE_R->filenos],
1291	;
1292	$asy->pipe_autodrain (0);
1293
1294	$asy
1295	};
1296
1297	} else {
1298	# pure perl
1299
1300	$SIG{$signal} ||= sub {
1301	local $!;
1302	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1303	undef $SIG_EV{$signal};
1304	};
1305
1306	# can't do signal processing without introducing races in pure perl,
1307	# so limit the signal latency.
1308	++$SIG_COUNT;
1309	$SIG_TW ||= AnyEvent->timer (
1310	after => $MAX_SIGNAL_LATENCY,
1311	interval => $MAX_SIGNAL_LATENCY,
1312	cb => sub { }, # just for the PERL_ASYNC_CHECK
1313	);
1314	}
1315
1316	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1317	}
1318
1319	sub signal {
1320	# probe for availability of Async::Interrupt
1321	if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1322	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1323
1324	$HAVE_ASYNC_INTERRUPT = 1;
1325	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1326	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1327
1328	} else {
1329	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1330
1331	require Fcntl;
1332
1333	if (AnyEvent::WIN32) {
1334	require AnyEvent::Util;
1335
1336	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1337	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1338	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1339	} else {
1340	pipe $SIGPIPE_R, $SIGPIPE_W;
1341	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1342	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1343
1344	# not strictly required, as $^F is normally 2, but let's make sure...
1345	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1346	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1347	}
1348
1349	$SIGPIPE_R
1350	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1351
1352	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1353	}
1354
1355	*signal = \&_signal;
1356	&signal
1357	}
1358
1359	sub AnyEvent::Base::signal::DESTROY {
1360	my ($signal, $cb) = @{$_[0]};
1361
1362	undef $SIG_TW	1479	undef $SIG_TW
1363	unless --$SIG_COUNT;	1480	unless --$SIG_COUNT;
		1481	}
1364		1482
		1483	our $_sig_name_init; $_sig_name_init = sub {
		1484	eval q{ # poor man's autoloading {}
		1485	undef $_sig_name_init;
		1486
		1487	if (_have_async_interrupt) {
		1488	*sig2num = \&Async::Interrupt::sig2num;
		1489	*sig2name = \&Async::Interrupt::sig2name;
		1490	} else {
		1491	require Config;
		1492
		1493	my %signame2num;
		1494	@signame2num{ split ' ', $Config::Config{sig_name} }
		1495	= split ' ', $Config::Config{sig_num};
		1496
		1497	my @signum2name;
		1498	@signum2name[values %signame2num] = keys %signame2num;
		1499
		1500	*sig2num = sub($) {
		1501	$_[0] > 0 ? shift : $signame2num{+shift}
		1502	};
		1503	*sig2name = sub ($) {
		1504	$_[0] > 0 ? $signum2name[+shift] : shift
		1505	};
		1506	}
		1507	};
		1508	die if $@;
		1509	};
		1510
		1511	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1512	sub sig2name($) { &$_sig_name_init; &sig2name }
		1513
		1514	sub signal {
		1515	eval q{ # poor man's autoloading {}
		1516	# probe for availability of Async::Interrupt
		1517	if (_have_async_interrupt) {
		1518	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
		1519
		1520	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1521	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
		1522
		1523	} else {
		1524	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1525
		1526	if (AnyEvent::WIN32) {
		1527	require AnyEvent::Util;
		1528
		1529	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1530	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1531	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1532	} else {
		1533	pipe $SIGPIPE_R, $SIGPIPE_W;
		1534	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
		1535	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1536
		1537	# not strictly required, as $^F is normally 2, but let's make sure...
		1538	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1539	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1540	}
		1541
		1542	$SIGPIPE_R
		1543	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1544
		1545	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
		1546	}
		1547
		1548	*signal = $HAVE_ASYNC_INTERRUPT
		1549	? sub {
		1550	my (undef, %arg) = @_;
		1551
		1552	# async::interrupt
		1553	my $signal = sig2num $arg{signal};
		1554	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1555
		1556	$SIG_ASY{$signal} ||= new Async::Interrupt
		1557	cb => sub { undef $SIG_EV{$signal} },
		1558	signal => $signal,
		1559	pipe => [$SIGPIPE_R->filenos],
		1560	pipe_autodrain => 0,
		1561	;
		1562
		1563	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1564	}
		1565	: sub {
		1566	my (undef, %arg) = @_;
		1567
		1568	# pure perl
		1569	my $signal = sig2name $arg{signal};
		1570	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1571
		1572	$SIG{$signal} ||= sub {
		1573	local $!;
		1574	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1575	undef $SIG_EV{$signal};
		1576	};
		1577
		1578	# can't do signal processing without introducing races in pure perl,
		1579	# so limit the signal latency.
		1580	_sig_add;
		1581
		1582	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1583	}
		1584	;
		1585
		1586	*AnyEvent::Base::signal::DESTROY = sub {
		1587	my ($signal, $cb) = @{$_[0]};
		1588
		1589	_sig_del;
		1590
1365	delete $SIG_CB{$signal}{$cb};	1591	delete $SIG_CB{$signal}{$cb};
1366		1592
		1593	$HAVE_ASYNC_INTERRUPT
		1594	? delete $SIG_ASY{$signal}
1367	# delete doesn't work with older perls - they then	1595	: # delete doesn't work with older perls - they then
1368	# print weird messages, or just unconditionally exit	1596	# print weird messages, or just unconditionally exit
1369	# instead of getting the default action.	1597	# instead of getting the default action.
1370	undef $SIG{$signal}	1598	undef $SIG{$signal}
1371	unless keys %{ $SIG_CB{$signal} };	1599	unless keys %{ $SIG_CB{$signal} };
		1600	};
		1601
		1602	*_signal_exec = sub {
		1603	$HAVE_ASYNC_INTERRUPT
		1604	? $SIGPIPE_R->drain
		1605	: sysread $SIGPIPE_R, (my $dummy), 9;
		1606
		1607	while (%SIG_EV) {
		1608	for (keys %SIG_EV) {
		1609	delete $SIG_EV{$_};
		1610	$_->() for values %{ $SIG_CB{$_} || {} };
		1611	}
		1612	}
		1613	};
		1614	};
		1615	die if $@;
		1616
		1617	&signal
1372	}	1618	}
1373		1619
1374	# default implementation for ->child	1620	# default implementation for ->child
1375		1621
1376	our %PID_CB;	1622	our %PID_CB;
1377	our $CHLD_W;	1623	our $CHLD_W;
1378	our $CHLD_DELAY_W;	1624	our $CHLD_DELAY_W;
1379	our $WNOHANG;	1625	our $WNOHANG;
1380		1626
1381	sub _sigchld {	1627	# used by many Impl's
1382	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1628	sub _emit_childstatus($$) {
1383	$_->($pid, $?)	1629	my (undef, $rpid, $rstatus) = @_;
		1630
		1631	$_->($rpid, $rstatus)
1384	for values %{ $PID_CB{$pid} || {} },	1632	for values %{ $PID_CB{$rpid} || {} },
1385	values %{ $PID_CB{0} || {} };	1633	values %{ $PID_CB{0} || {} };
1386	}
1387	}	1634	}
1388		1635
1389	sub child {	1636	sub child {
		1637	eval q{ # poor man's autoloading {}
		1638	*_sigchld = sub {
		1639	my $pid;
		1640
		1641	AnyEvent->_emit_childstatus ($pid, $?)
		1642	while ($pid = waitpid -1, $WNOHANG) > 0;
		1643	};
		1644
		1645	*child = sub {
1390	my (undef, %arg) = @_;	1646	my (undef, %arg) = @_;
1391		1647
1392	defined (my $pid = $arg{pid} + 0)	1648	defined (my $pid = $arg{pid} + 0)
1393	or Carp::croak "required option 'pid' is missing";	1649	or Carp::croak "required option 'pid' is missing";
1394		1650
1395	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1651	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1396		1652
1397	# WNOHANG is almost cetrainly 1 everywhere	1653	# WNOHANG is almost cetrainly 1 everywhere
1398	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/	1654	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1399	? 1	1655	? 1
1400	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1656	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1401		1657
1402	unless ($CHLD_W) {	1658	unless ($CHLD_W) {
1403	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1659	$CHLD_W = AE::signal CHLD => \&_sigchld;
1404	# child could be a zombie already, so make at least one round	1660	# child could be a zombie already, so make at least one round
1405	&_sigchld;	1661	&_sigchld;
1406	}	1662	}
1407		1663
1408	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1664	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1409	}	1665	};
1410		1666
1411	sub AnyEvent::Base::child::DESTROY {	1667	*AnyEvent::Base::child::DESTROY = sub {
1412	my ($pid, $cb) = @{$_[0]};	1668	my ($pid, $cb) = @{$_[0]};
1413		1669
1414	delete $PID_CB{$pid}{$cb};	1670	delete $PID_CB{$pid}{$cb};
1415	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1671	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1416		1672
1417	undef $CHLD_W unless keys %PID_CB;	1673	undef $CHLD_W unless keys %PID_CB;
		1674	};
		1675	};
		1676	die if $@;
		1677
		1678	&child
1418	}	1679	}
1419		1680
1420	# idle emulation is done by simply using a timer, regardless	1681	# idle emulation is done by simply using a timer, regardless
1421	# of whether the process is idle or not, and not letting	1682	# of whether the process is idle or not, and not letting
1422	# the callback use more than 50% of the time.	1683	# the callback use more than 50% of the time.
1423	sub idle {	1684	sub idle {
		1685	eval q{ # poor man's autoloading {}
		1686	*idle = sub {
1424	my (undef, %arg) = @_;	1687	my (undef, %arg) = @_;
1425		1688
1426	my ($cb, $w, $rcb) = $arg{cb};	1689	my ($cb, $w, $rcb) = $arg{cb};
1427		1690
1428	$rcb = sub {	1691	$rcb = sub {
1429	if ($cb) {	1692	if ($cb) {
1430	$w = _time;	1693	$w = _time;
1431	&$cb;	1694	&$cb;
1432	$w = _time - $w;	1695	$w = _time - $w;
1433		1696
1434	# never use more then 50% of the time for the idle watcher,	1697	# never use more then 50% of the time for the idle watcher,
1435	# within some limits	1698	# within some limits
1436	$w = 0.0001 if $w < 0.0001;	1699	$w = 0.0001 if $w < 0.0001;
1437	$w = 5 if $w > 5;	1700	$w = 5 if $w > 5;
1438		1701
1439	$w = AnyEvent->timer (after => $w, cb => $rcb);	1702	$w = AE::timer $w, 0, $rcb;
1440	} else {	1703	} else {
1441	# clean up...	1704	# clean up...
1442	undef $w;	1705	undef $w;
1443	undef $rcb;	1706	undef $rcb;
		1707	}
		1708	};
		1709
		1710	$w = AE::timer 0.05, 0, $rcb;
		1711
		1712	bless \\$cb, "AnyEvent::Base::idle"
1444	}	1713	};
		1714
		1715	*AnyEvent::Base::idle::DESTROY = sub {
		1716	undef $${$_[0]};
		1717	};
1445	};	1718	};
		1719	die if $@;
1446		1720
1447	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1721	&idle
1448
1449	bless \\$cb, "AnyEvent::Base::idle"
1450	}
1451
1452	sub AnyEvent::Base::idle::DESTROY {
1453	undef $${$_[0]};
1454	}	1722	}
1455		1723
1456	package AnyEvent::CondVar;	1724	package AnyEvent::CondVar;
1457		1725
1458	our @ISA = AnyEvent::CondVar::Base::;	1726	our @ISA = AnyEvent::CondVar::Base::;
…		…
1506	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1774	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1507	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1775	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1508	}	1776	}
1509		1777
1510	sub cb {	1778	sub cb {
1511	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1779	my $cv = shift;
		1780
		1781	@_
		1782	and $cv->{_ae_cb} = shift
		1783	and $cv->{_ae_sent}
		1784	and (delete $cv->{_ae_cb})->($cv);
		1785
1512	$_[0]{_ae_cb}	1786	$cv->{_ae_cb}
1513	}	1787	}
1514		1788
1515	sub begin {	1789	sub begin {
1516	++$_[0]{_ae_counter};	1790	++$_[0]{_ae_counter};
1517	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1791	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1726	warn "read: $input\n"; # output what has been read	2000	warn "read: $input\n"; # output what has been read
1727	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2001	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1728	},	2002	},
1729	);	2003	);
1730		2004
1731	my $time_watcher; # can only be used once
1732
1733	sub new_timer {
1734	$timer = AnyEvent->timer (after => 1, cb => sub {	2005	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1735	warn "timeout\n"; # print 'timeout' about every second	2006	warn "timeout\n"; # print 'timeout' at most every second
1736	&new_timer; # and restart the time
1737	});	2007	});
1738	}
1739
1740	new_timer; # create first timer
1741		2008
1742	$cv->recv; # wait until user enters /^q/i	2009	$cv->recv; # wait until user enters /^q/i
1743		2010
1744	=head1 REAL-WORLD EXAMPLE	2011	=head1 REAL-WORLD EXAMPLE
1745		2012
…		…
1818		2085
1819	The actual code goes further and collects all errors (C<die>s, exceptions)	2086	The actual code goes further and collects all errors (C<die>s, exceptions)
1820	that occurred during request processing. The C<result> method detects	2087	that occurred during request processing. The C<result> method detects
1821	whether an exception as thrown (it is stored inside the $txn object)	2088	whether an exception as thrown (it is stored inside the $txn object)
1822	and just throws the exception, which means connection errors and other	2089	and just throws the exception, which means connection errors and other
1823	problems get reported tot he code that tries to use the result, not in a	2090	problems get reported to the code that tries to use the result, not in a
1824	random callback.	2091	random callback.
1825		2092
1826	All of this enables the following usage styles:	2093	All of this enables the following usage styles:
1827		2094
1828	1. Blocking:	2095	1. Blocking:
…		…
1876	through AnyEvent. The benchmark creates a lot of timers (with a zero	2143	through AnyEvent. The benchmark creates a lot of timers (with a zero
1877	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2144	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1878	which it is), lets them fire exactly once and destroys them again.	2145	which it is), lets them fire exactly once and destroys them again.
1879		2146
1880	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2147	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1881	distribution.	2148	distribution. It uses the L<AE> interface, which makes a real difference
		2149	for the EV and Perl backends only.
1882		2150
1883	=head3 Explanation of the columns	2151	=head3 Explanation of the columns
1884		2152
1885	I<watcher> is the number of event watchers created/destroyed. Since	2153	I<watcher> is the number of event watchers created/destroyed. Since
1886	different event models feature vastly different performances, each event	2154	different event models feature vastly different performances, each event
…		…
1907	watcher.	2175	watcher.
1908		2176
1909	=head3 Results	2177	=head3 Results
1910		2178
1911	name watchers bytes create invoke destroy comment	2179	name watchers bytes create invoke destroy comment
1912	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2180	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1913	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2181	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1914	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2182	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1915	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2183	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1916	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2184	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1917	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2185	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1918	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2186	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1919	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2187	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1920	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2188	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1921	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2189	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1922	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2190	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1923	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2191	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1924		2192
1925	=head3 Discussion	2193	=head3 Discussion
1926		2194
1927	The benchmark does I<not> measure scalability of the event loop very	2195	The benchmark does I<not> measure scalability of the event loop very
1928	well. For example, a select-based event loop (such as the pure perl one)	2196	well. For example, a select-based event loop (such as the pure perl one)
…		…
1940	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2208	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1941	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2209	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1942	cycles with POE.	2210	cycles with POE.
1943		2211
1944	C<EV> is the sole leader regarding speed and memory use, which are both	2212	C<EV> is the sole leader regarding speed and memory use, which are both
1945	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2213	maximal/minimal, respectively. When using the L<AE> API there is zero
		2214	overhead (when going through the AnyEvent API create is about 5-6 times
		2215	slower, with other times being equal, so still uses far less memory than
1946	far less memory than any other event loop and is still faster than Event	2216	any other event loop and is still faster than Event natively).
1947	natively.
1948		2217
1949	The pure perl implementation is hit in a few sweet spots (both the	2218	The pure perl implementation is hit in a few sweet spots (both the
1950	constant timeout and the use of a single fd hit optimisations in the perl	2219	constant timeout and the use of a single fd hit optimisations in the perl
1951	interpreter and the backend itself). Nevertheless this shows that it	2220	interpreter and the backend itself). Nevertheless this shows that it
1952	adds very little overhead in itself. Like any select-based backend its	2221	adds very little overhead in itself. Like any select-based backend its
…		…
2026	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2295	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2027	(1%) are active. This mirrors the activity of large servers with many	2296	(1%) are active. This mirrors the activity of large servers with many
2028	connections, most of which are idle at any one point in time.	2297	connections, most of which are idle at any one point in time.
2029		2298
2030	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2299	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2031	distribution.	2300	distribution. It uses the L<AE> interface, which makes a real difference
		2301	for the EV and Perl backends only.
2032		2302
2033	=head3 Explanation of the columns	2303	=head3 Explanation of the columns
2034		2304
2035	I<sockets> is the number of sockets, and twice the number of "servers" (as	2305	I<sockets> is the number of sockets, and twice the number of "servers" (as
2036	each server has a read and write socket end).	2306	each server has a read and write socket end).
…		…
2044	a new one that moves the timeout into the future.	2314	a new one that moves the timeout into the future.
2045		2315
2046	=head3 Results	2316	=head3 Results
2047		2317
2048	name sockets create request	2318	name sockets create request
2049	EV 20000 69.01 11.16	2319	EV 20000 62.66 7.99
2050	Perl 20000 73.32 35.87	2320	Perl 20000 68.32 32.64
2051	IOAsync 20000 157.00 98.14 epoll	2321	IOAsync 20000 174.06 101.15 epoll
2052	IOAsync 20000 159.31 616.06 poll	2322	IOAsync 20000 174.67 610.84 poll
2053	Event 20000 212.62 257.32	2323	Event 20000 202.69 242.91
2054	Glib 20000 651.16 1896.30	2324	Glib 20000 557.01 1689.52
2055	POE 20000 349.67 12317.24 uses POE::Loop::Event	2325	POE 20000 341.54 12086.32 uses POE::Loop::Event
2056		2326
2057	=head3 Discussion	2327	=head3 Discussion
2058		2328
2059	This benchmark I<does> measure scalability and overall performance of the	2329	This benchmark I<does> measure scalability and overall performance of the
2060	particular event loop.	2330	particular event loop.
…		…
2186	As you can see, the AnyEvent + EV combination even beats the	2456	As you can see, the AnyEvent + EV combination even beats the
2187	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2457	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2188	backend easily beats IO::Lambda and POE.	2458	backend easily beats IO::Lambda and POE.
2189		2459
2190	And even the 100% non-blocking version written using the high-level (and	2460	And even the 100% non-blocking version written using the high-level (and
2191	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2461	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2192	large margin, even though it does all of DNS, tcp-connect and socket I/O	2462	higher level ("unoptimised") abstractions by a large margin, even though
2193	in a non-blocking way.	2463	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2194		2464
2195	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2465	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2196	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2466	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2197	part of the IO::lambda distribution and were used without any changes.	2467	part of the IO::Lambda distribution and were used without any changes.
2198		2468
2199		2469
2200	=head1 SIGNALS	2470	=head1 SIGNALS
2201		2471
2202	AnyEvent currently installs handlers for these signals:	2472	AnyEvent currently installs handlers for these signals:
…		…
2244	it's built-in modules) are required to use it.	2514	it's built-in modules) are required to use it.
2245		2515
2246	That does not mean that AnyEvent won't take advantage of some additional	2516	That does not mean that AnyEvent won't take advantage of some additional
2247	modules if they are installed.	2517	modules if they are installed.
2248		2518
2249	This section epxlains which additional modules will be used, and how they	2519	This section explains which additional modules will be used, and how they
2250	affect AnyEvent's operetion.	2520	affect AnyEvent's operation.
2251		2521
2252	=over 4	2522	=over 4
2253		2523
2254	=item L<Async::Interrupt>	2524	=item L<Async::Interrupt>
2255		2525
2256	This slightly arcane module is used to implement fast signal handling: To	2526	This slightly arcane module is used to implement fast signal handling: To
2257	my knowledge, there is no way to do completely race-free and quick	2527	my knowledge, there is no way to do completely race-free and quick
2258	signal handling in pure perl. To ensure that signals still get	2528	signal handling in pure perl. To ensure that signals still get
2259	delivered, AnyEvent will start an interval timer to wake up perl (and	2529	delivered, AnyEvent will start an interval timer to wake up perl (and
2260	catch the signals) with soemd elay (default is 10 seconds, look for	2530	catch the signals) with some delay (default is 10 seconds, look for
2261	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2531	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2262		2532
2263	If this module is available, then it will be used to implement signal	2533	If this module is available, then it will be used to implement signal
2264	catching, which means that signals will not be delayed, and the event loop	2534	catching, which means that signals will not be delayed, and the event loop
2265	will not be interrupted regularly, which is more efficient (And good for	2535	will not be interrupted regularly, which is more efficient (and good for
2266	battery life on laptops).	2536	battery life on laptops).
2267		2537
2268	This affects not just the pure-perl event loop, but also other event loops	2538	This affects not just the pure-perl event loop, but also other event loops
2269	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2539	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2540
		2541	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2542	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2543	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2544	does nothing for those backends.
2270		2545
2271	=item L<EV>	2546	=item L<EV>
2272		2547
2273	This module isn't really "optional", as it is simply one of the backend	2548	This module isn't really "optional", as it is simply one of the backend
2274	event loops that AnyEvent can use. However, it is simply the best event	2549	event loops that AnyEvent can use. However, it is simply the best event
…		…
2277	automatic timer adjustments even when no monotonic clock is available,	2552	automatic timer adjustments even when no monotonic clock is available,
2278	can take avdantage of advanced kernel interfaces such as C<epoll> and	2553	can take avdantage of advanced kernel interfaces such as C<epoll> and
2279	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2554	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2280	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2555	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2281		2556
		2557	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2558	then this module will do nothing for you.
		2559
2282	=item L<Guard>	2560	=item L<Guard>
2283		2561
2284	The guard module, when used, will be used to implement	2562	The guard module, when used, will be used to implement
2285	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2563	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2286	lot less memory), but otherwise doesn't affect guard operation much. It is	2564	lot less memory), but otherwise doesn't affect guard operation much. It is
2287	purely used for performance.	2565	purely used for performance.
2288		2566
2289	=item L<JSON> and L<JSON::XS>	2567	=item L<JSON> and L<JSON::XS>
2290		2568
2291	This module is required when you want to read or write JSON data via	2569	One of these modules is required when you want to read or write JSON data
2292	L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2570	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2293	advantage of the ulta-high-speed L<JSON::XS> module when it is installed.	2571	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2294
2295	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2296	installed.
2297		2572
2298	=item L<Net::SSLeay>	2573	=item L<Net::SSLeay>
2299		2574
2300	Implementing TLS/SSL in Perl is certainly interesting, but not very	2575	Implementing TLS/SSL in Perl is certainly interesting, but not very
2301	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2576	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
…		…
2312		2587
2313		2588
2314	=head1 FORK	2589	=head1 FORK
2315		2590
2316	Most event libraries are not fork-safe. The ones who are usually are	2591	Most event libraries are not fork-safe. The ones who are usually are
2317	because they rely on inefficient but fork-safe C<select> or C<poll>	2592	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2318	calls. Only L<EV> is fully fork-aware.	2593	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2594	are usually badly thought-out hacks that are incompatible with fork in
		2595	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2596	continue event-processing in both parent and child (or both, if you know
		2597	what you are doing).
		2598
		2599	This means that, in general, you cannot fork and do event processing in
		2600	the child if the event library was initialised before the fork (which
		2601	usually happens when the first AnyEvent watcher is created, or the library
		2602	is loaded).
2319		2603
2320	If you have to fork, you must either do so I<before> creating your first	2604	If you have to fork, you must either do so I<before> creating your first
2321	watcher OR you must not use AnyEvent at all in the child OR you must do	2605	watcher OR you must not use AnyEvent at all in the child OR you must do
2322	something completely out of the scope of AnyEvent.	2606	something completely out of the scope of AnyEvent.
		2607
		2608	The problem of doing event processing in the parent I<and> the child
		2609	is much more complicated: even for backends that I<are> fork-aware or
		2610	fork-safe, their behaviour is not usually what you want: fork clones all
		2611	watchers, that means all timers, I/O watchers etc. are active in both
		2612	parent and child, which is almost never what you want. USing C<exec>
		2613	to start worker children from some kind of manage rprocess is usually
		2614	preferred, because it is much easier and cleaner, at the expense of having
		2615	to have another binary.
2323		2616
2324		2617
2325	=head1 SECURITY CONSIDERATIONS	2618	=head1 SECURITY CONSIDERATIONS
2326		2619
2327	AnyEvent can be forced to load any event model via	2620	AnyEvent can be forced to load any event model via
…		…
2365	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2658	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2366		2659
2367	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2660	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2368	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2661	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2369	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2662	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2370	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.	2663	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2371		2664
2372	Non-blocking file handles, sockets, TCP clients and	2665	Non-blocking file handles, sockets, TCP clients and
2373	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2666	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2374		2667
2375	Asynchronous DNS: L<AnyEvent::DNS>.	2668	Asynchronous DNS: L<AnyEvent::DNS>.

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