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Revision 1.329 by root, Sun Jul 11 05:44:22 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?
…		…
127	use AnyEvent;	138	use AnyEvent;
128		139
129	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
130		141
131	The I<likely> means that, if any module loads another event model and	142	The I<likely> means that, if any module loads another event model and
132	starts using it, all bets are off. Maybe you should tell their authors to	143	starts using it, all bets are off - this case should be very rare though,
133	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
134		146
135	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called
136	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	148	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
137	explicitly and enjoy the high availability of that event loop :)	149	explicitly and enjoy the high availability of that event loop :)
138		150
…		…
173	my variables are only visible after the statement in which they are	185	my variables are only visible after the statement in which they are
174	declared.	186	declared.
175		187
176	=head2 I/O WATCHERS	188	=head2 I/O WATCHERS
177		189
		190	$w = AnyEvent->io (
		191	fh => <filehandle_or_fileno>,
		192	poll => <"r" or "w">,
		193	cb => <callback>,
		194	);
		195
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	196	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
180		198
181	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch	199	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	200	for events (AnyEvent might or might not keep a reference to this file
183	handle). Note that only file handles pointing to things for which	201	handle). Note that only file handles pointing to things for which
184	non-blocking operation makes sense are allowed. This includes sockets,	202	non-blocking operation makes sense are allowed. This includes sockets,
185	most character devices, pipes, fifos and so on, but not for example files	203	most character devices, pipes, fifos and so on, but not for example files
186	or block devices.	204	or block devices.
…		…
211	undef $w;	229	undef $w;
212	});	230	});
213		231
214	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
215		233
		234	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		235
		236	$w = AnyEvent->timer (
		237	after => <fractional_seconds>,
		238	interval => <fractional_seconds>,
		239	cb => <callback>,
		240	);
		241
216	You can create a time watcher by calling the C<< AnyEvent->timer >>	242	You can create a time watcher by calling the C<< AnyEvent->timer >>
217	method with the following mandatory arguments:	243	method with the following mandatory arguments:
218		244
219	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
220	supported) the callback should be invoked. C<cb> is the callback to invoke	246	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
341	might affect timers and time-outs.	367	might affect timers and time-outs.
342		368
343	When this is the case, you can call this method, which will update the	369	When this is the case, you can call this method, which will update the
344	event loop's idea of "current time".	370	event loop's idea of "current time".
345		371
		372	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		373	when mod_perl executes the script, then the event loop will have the wrong
		374	idea about the "current time" (being potentially far in the past, when the
		375	script ran the last time). In that case you should arrange a call to C<<
		376	AnyEvent->now_update >> each time the web server process wakes up again
		377	(e.g. at the start of your script, or in a handler).
		378
346	Note that updating the time I<might> cause some events to be handled.	379	Note that updating the time I<might> cause some events to be handled.
347		380
348	=back	381	=back
349		382
350	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351		386
352	You can watch for signals using a signal watcher, C<signal> is the signal	387	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	388	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
355		390
…		…
361	invocation, and callback invocation will be synchronous. Synchronous means	396	invocation, and callback invocation will be synchronous. Synchronous means
362	that it might take a while until the signal gets handled by the process,	397	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.	398	but it is guaranteed not to interrupt any other callbacks.
364		399
365	The main advantage of using these watchers is that you can share a signal	400	The main advantage of using these watchers is that you can share a signal
366	between multiple watchers.	401	between multiple watchers, and AnyEvent will ensure that signals will not
		402	interrupt your program at bad times.
367		403
368	This watcher might use C<%SIG>, so programs overwriting those signals	404	This watcher might use C<%SIG> (depending on the event loop used),
369	directly will likely not work correctly.	405	so programs overwriting those signals directly will likely not work
		406	correctly.
370		407
371	Example: exit on SIGINT	408	Example: exit on SIGINT
372		409
373	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
374		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling) or
		421	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		422	latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
		429	=head3 Signal Races, Delays and Workarounds
		430
		431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		432	callbacks to signals in a generic way, which is a pity, as you cannot
		433	do race-free signal handling in perl, requiring C libraries for
		434	this. AnyEvent will try to do it's best, which means in some cases,
		435	signals will be delayed. The maximum time a signal might be delayed is
		436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		437	variable can be changed only before the first signal watcher is created,
		438	and should be left alone otherwise. This variable determines how often
		439	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		440	will cause fewer spurious wake-ups, which is better for power and CPU
		441	saving.
		442
		443	All these problems can be avoided by installing the optional
		444	L<Async::Interrupt> module, which works with most event loops. It will not
		445	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		446	(and not with L<POE> currently, as POE does it's own workaround with
		447	one-second latency). For those, you just have to suffer the delays.
		448
375	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
376		450
		451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		452
377	You can also watch on a child process exit and catch its exit status.	453	You can also watch on a child process exit and catch its exit status.
378		454
379	The child process is specified by the C<pid> argument (if set to C<0>, it	455	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	456	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	457	croak). The watcher will be triggered only when the child process has
382	any trace events (stopped/continued).	458	finished and an exit status is available, not on any trace events
		459	(stopped/continued).
383		460
384	The callback will be called with the pid and exit status (as returned by	461	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	462	waitpid), so unlike other watcher types, you I<can> rely on child watcher
386	callback arguments.	463	callback arguments.
387		464
…		…
403		480
404	This means you cannot create a child watcher as the very first	481	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	482	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	483	watcher before you C<fork> the child (alternatively, you can call
407	C<AnyEvent::detect>).	484	C<AnyEvent::detect>).
		485
		486	As most event loops do not support waiting for child events, they will be
		487	emulated by AnyEvent in most cases, in which the latency and race problems
		488	mentioned in the description of signal watchers apply.
408		489
409	Example: fork a process and wait for it	490	Example: fork a process and wait for it
410		491
411	my $done = AnyEvent->condvar;	492	my $done = AnyEvent->condvar;
412		493
…		…
424	# do something else, then wait for process exit	505	# do something else, then wait for process exit
425	$done->recv;	506	$done->recv;
426		507
427	=head2 IDLE WATCHERS	508	=head2 IDLE WATCHERS
428		509
429	Sometimes there is a need to do something, but it is not so important	510	$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		511
434	Idle watchers ideally get invoked when the event loop has nothing	512	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	513	either the watcher is destroyed or new events have been detected.
436	events. Instead of blocking, the idle watcher is invoked.
437		514
438	Most event loops unfortunately do not really support idle watchers (only	515	Idle watchers are useful when there is a need to do something, but it
		516	is not so important (or wise) to do it instantly. The callback will be
		517	invoked only when there is "nothing better to do", which is usually
		518	defined as "all outstanding events have been handled and no new events
		519	have been detected". That means that idle watchers ideally get invoked
		520	when the event loop has just polled for new events but none have been
		521	detected. Instead of blocking to wait for more events, the idle watchers
		522	will be invoked.
		523
		524	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	525	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
440	will simply call the callback "from time to time".	526	will simply call the callback "from time to time".
441		527
442	Example: read lines from STDIN, but only process them when the	528	Example: read lines from STDIN, but only process them when the
443	program is otherwise idle:	529	program is otherwise idle:
…		…
459	});	545	});
460	});	546	});
461		547
462	=head2 CONDITION VARIABLES	548	=head2 CONDITION VARIABLES
463		549
		550	$cv = AnyEvent->condvar;
		551
		552	$cv->send (<list>);
		553	my @res = $cv->recv;
		554
464	If you are familiar with some event loops you will know that all of them	555	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	556	require you to run some blocking "loop", "run" or similar function that
466	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
467		558
468	AnyEvent is different, it expects somebody else to run the event loop and	559	AnyEvent is slightly different: it expects somebody else to run the event
469	will only block when necessary (usually when told by the user).	560	loop and will only block when necessary (usually when told by the user).
470		561
471	The instrument to do that is called a "condition variable", so called	562	The tool to do that is called a "condition variable", so called because
472	because they represent a condition that must become true.	563	they represent a condition that must become true.
		564
		565	Now is probably a good time to look at the examples further below.
473		566
474	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
475	>> method, usually without arguments. The only argument pair allowed is	568	>> 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	569	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	570	becomes true, with the condition variable as the first argument (but not
479	the results).	571	the results).
480		572
481	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
482	by calling the C<send> method (or calling the condition variable as if it	574	by calling the C<send> method (or calling the condition variable as if it
483	were a callback, read about the caveats in the description for the C<<	575	were a callback, read about the caveats in the description for the C<<
484	->send >> method).	576	->send >> method).
485		577
486	Condition variables are similar to callbacks, except that you can	578	Since condition variables are the most complex part of the AnyEvent API, here are
487	optionally wait for them. They can also be called merge points - points	579	some different mental models of what they are - pick the ones you can connect to:
488	in time where multiple outstanding events have been processed. And yet	580
489	another way to call them is transactions - each condition variable can be	581	=over 4
490	used to represent a transaction, which finishes at some point and delivers	582
491	a result.	583	=item * Condition variables are like callbacks - you can call them (and pass them instead
		584	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		585
		586	=item * Condition variables are signals - one side can emit or send them,
		587	the other side can wait for them, or install a handler that is called when
		588	the signal fires.
		589
		590	=item * Condition variables are like "Merge Points" - points in your program
		591	where you merge multiple independent results/control flows into one.
		592
		593	=item * Condition variables represent a transaction - function that start
		594	some kind of transaction can return them, leaving the caller the choice
		595	between waiting in a blocking fashion, or setting a callback.
		596
		597	=item * Condition variables represent future values, or promises to deliver
		598	some result, long before the result is available.
		599
		600	=back
492		601
493	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
494	for example, if you write a module that does asynchronous http requests,	603	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	604	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	605	availability of results. The user can either act when the callback is
…		…
517	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
518	for the send to occur.	627	for the send to occur.
519		628
520	Example: wait for a timer.	629	Example: wait for a timer.
521		630
522	# wait till the result is ready	631	# condition: "wait till the timer is fired"
523	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
524		633
525	# do something such as adding a timer	634	# create the timer - we could wait for, say
526	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
527	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
528	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
529	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
530	after => 1,	639	after => 1,
531	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
532	);	641	);
533		642
534	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
535	# calls send	644	# calls ->send
536	$result_ready->recv;	645	$timer_fired->recv;
537		646
538	Example: wait for a timer, but take advantage of the fact that	647	Example: wait for a timer, but take advantage of the fact that condition
539	condition variables are also code references.	648	variables are also callable directly.
540		649
541	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
542	my $delay = AnyEvent->timer (after => 5, cb => $done);	651	my $delay = AnyEvent->timer (after => 5, cb => $done);
543	$done->recv;	652	$done->recv;
544		653
…		…
550		659
551	...	660	...
552		661
553	my @info = $couchdb->info->recv;	662	my @info = $couchdb->info->recv;
554		663
555	And this is how you would just ste a callback to be called whenever the	664	And this is how you would just set a callback to be called whenever the
556	results are available:	665	results are available:
557		666
558	$couchdb->info->cb (sub {	667	$couchdb->info->cb (sub {
559	my @info = $_[0]->recv;	668	my @info = $_[0]->recv;
560	});	669	});
…		…
578	immediately from within send.	687	immediately from within send.
579		688
580	Any arguments passed to the C<send> call will be returned by all	689	Any arguments passed to the C<send> call will be returned by all
581	future C<< ->recv >> calls.	690	future C<< ->recv >> calls.
582		691
583	Condition variables are overloaded so one can call them directly	692	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	693	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	694	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		695
592	=item $cv->croak ($error)	696	=item $cv->croak ($error)
593		697
594	Similar to send, but causes all call's to C<< ->recv >> to invoke	698	Similar to send, but causes all call's to C<< ->recv >> to invoke
595	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
596		700
597	This can be used to signal any errors to the condition variable	701	This can be used to signal any errors to the condition variable
598	user/consumer.	702	user/consumer. Doing it this way instead of calling C<croak> directly
		703	delays the error detetcion, but has the overwhelmign advantage that it
		704	diagnoses the error at the place where the result is expected, and not
		705	deep in some event clalback without connection to the actual code causing
		706	the problem.
599		707
600	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
601		709
602	=item $cv->end	710	=item $cv->end
603		711
…		…
605	one. For example, a function that pings many hosts in parallel might want	713	one. For example, a function that pings many hosts in parallel might want
606	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
607		715
608	Every call to C<< ->begin >> will increment a counter, and every call to	716	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	717	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	718	>>, 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	719	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.	720	>>, but that is not required. If no group callback was set, C<send> will
		721	be called without any arguments.
613		722
614	You can think of C<< $cv->send >> giving you an OR condition (one call	723	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	724	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).	725	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
617		726
…		…
644	begung can potentially be zero:	753	begung can potentially be zero:
645		754
646	my $cv = AnyEvent->condvar;	755	my $cv = AnyEvent->condvar;
647		756
648	my %result;	757	my %result;
649	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
650		759
651	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
652	$cv->begin;	761	$cv->begin;
653	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
654	$result{$host} = ...;	763	$result{$host} = ...;
…		…
699	function will call C<croak>.	808	function will call C<croak>.
700		809
701	In list context, all parameters passed to C<send> will be returned,	810	In list context, all parameters passed to C<send> will be returned,
702	in scalar context only the first one will be returned.	811	in scalar context only the first one will be returned.
703		812
		813	Note that doing a blocking wait in a callback is not supported by any
		814	event loop, that is, recursive invocation of a blocking C<< ->recv
		815	>> is not allowed, and the C<recv> call will C<croak> if such a
		816	condition is detected. This condition can be slightly loosened by using
		817	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		818	any thread that doesn't run the event loop itself.
		819
704	Not all event models support a blocking wait - some die in that case	820	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	821	(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	822	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	823	caller decide whether the call will block or not (for example, by coupling
708	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
709	callbacks so the caller knows that getting the result will not block,	825	callbacks so the caller knows that getting the result will not block,
710	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
711		827
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	828	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	829	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	830	time). This will work even when the event loop does not support blocking
726	waits otherwise.	831	waits otherwise.
727		832
…		…
733	=item $cb = $cv->cb ($cb->($cv))	838	=item $cb = $cv->cb ($cb->($cv))
734		839
735	This is a mutator function that returns the callback set and optionally	840	This is a mutator function that returns the callback set and optionally
736	replaces it before doing so.	841	replaces it before doing so.
737		842
738	The callback will be called when the condition becomes "true", i.e. when	843	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	844	"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	845	the only argument being the condition variable itself. Calling C<recv>
741	is guaranteed not to block.	846	inside the callback or at any later time is guaranteed not to block.
742		847
743	=back	848	=back
744		849
		850	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		851
		852	The available backend classes are (every class has its own manpage):
		853
		854	=over 4
		855
		856	=item Backends that are autoprobed when no other event loop can be found.
		857
		858	EV is the preferred backend when no other event loop seems to be in
		859	use. If EV is not installed, then AnyEvent will fall back to its own
		860	pure-perl implementation, which is available everywhere as it comes with
		861	AnyEvent itself.
		862
		863	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		864	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		865
		866	=item Backends that are transparently being picked up when they are used.
		867
		868	These will be used when they are currently loaded when the first watcher
		869	is created, in which case it is assumed that the application is using
		870	them. This means that AnyEvent will automatically pick the right backend
		871	when the main program loads an event module before anything starts to
		872	create watchers. Nothing special needs to be done by the main program.
		873
		874	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		875	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		876	AnyEvent::Impl::Tk based on Tk, very broken.
		877	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		878	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		879	AnyEvent::Impl::Irssi used when running within irssi.
		880
		881	=item Backends with special needs.
		882
		883	Qt requires the Qt::Application to be instantiated first, but will
		884	otherwise be picked up automatically. As long as the main program
		885	instantiates the application before any AnyEvent watchers are created,
		886	everything should just work.
		887
		888	AnyEvent::Impl::Qt based on Qt.
		889
		890	Support for IO::Async can only be partial, as it is too broken and
		891	architecturally limited to even support the AnyEvent API. It also
		892	is the only event loop that needs the loop to be set explicitly, so
		893	it can only be used by a main program knowing about AnyEvent. See
		894	L<AnyEvent::Impl::Async> for the gory details.
		895
		896	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		897
		898	=item Event loops that are indirectly supported via other backends.
		899
		900	Some event loops can be supported via other modules:
		901
		902	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		903
		904	B<WxWidgets> has no support for watching file handles. However, you can
		905	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		906	polls 20 times per second, which was considered to be too horrible to even
		907	consider for AnyEvent.
		908
		909	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		910	backend, so it can be supported through POE.
		911
		912	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		913	load L<POE> when detecting them, in the hope that POE will pick them up,
		914	in which case everything will be automatic.
		915
		916	=back
		917
745	=head1 GLOBAL VARIABLES AND FUNCTIONS	918	=head1 GLOBAL VARIABLES AND FUNCTIONS
746		919
		920	These are not normally required to use AnyEvent, but can be useful to
		921	write AnyEvent extension modules.
		922
747	=over 4	923	=over 4
748		924
749	=item $AnyEvent::MODEL	925	=item $AnyEvent::MODEL
750		926
751	Contains C<undef> until the first watcher is being created. Then it	927	Contains C<undef> until the first watcher is being created, before the
		928	backend has been autodetected.
		929
752	contains the event model that is being used, which is the name of the	930	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	931	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	932	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>).	933	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
756		934	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		935
782	=item AnyEvent::detect	936	=item AnyEvent::detect
783		937
784	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	938	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
785	if necessary. You should only call this function right before you would	939	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	940	have created an AnyEvent watcher anyway, that is, as late as possible at
787	runtime.	941	runtime, and not e.g. while initialising of your module.
		942
		943	If you need to do some initialisation before AnyEvent watchers are
		944	created, use C<post_detect>.
788		945
789	=item $guard = AnyEvent::post_detect { BLOCK }	946	=item $guard = AnyEvent::post_detect { BLOCK }
790		947
791	Arranges for the code block to be executed as soon as the event model is	948	Arranges for the code block to be executed as soon as the event model is
792	autodetected (or immediately if this has already happened).	949	autodetected (or immediately if this has already happened).
793		950
		951	The block will be executed I<after> the actual backend has been detected
		952	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		953	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		954	other initialisations - see the sources of L<AnyEvent::Strict> or
		955	L<AnyEvent::AIO> to see how this is used.
		956
		957	The most common usage is to create some global watchers, without forcing
		958	event module detection too early, for example, L<AnyEvent::AIO> creates
		959	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		960	avoid autodetecting the event module at load time.
		961
794	If called in scalar or list context, then it creates and returns an object	962	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	963	that automatically removes the callback again when it is destroyed (or
		964	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
796	L<Coro::BDB> for a case where this is useful.	965	a case where this is useful.
		966
		967	Example: Create a watcher for the IO::AIO module and store it in
		968	C<$WATCHER>. Only do so after the event loop is initialised, though.
		969
		970	our WATCHER;
		971
		972	my $guard = AnyEvent::post_detect {
		973	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		974	};
		975
		976	# the ||= is important in case post_detect immediately runs the block,
		977	# as to not clobber the newly-created watcher. assigning both watcher and
		978	# post_detect guard to the same variable has the advantage of users being
		979	# able to just C<undef $WATCHER> if the watcher causes them grief.
		980
		981	$WATCHER ||= $guard;
797		982
798	=item @AnyEvent::post_detect	983	=item @AnyEvent::post_detect
799		984
800	If there are any code references in this array (you can C<push> to it	985	If there are any code references in this array (you can C<push> to it
801	before or after loading AnyEvent), then they will called directly after	986	before or after loading AnyEvent), then they will called directly after
802	the event loop has been chosen.	987	the event loop has been chosen.
803		988
804	You should check C<$AnyEvent::MODEL> before adding to this array, though:	989	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,	990	if it is defined then the event loop has already been detected, and the
806	and the array will be ignored.	991	array will be ignored.
807		992
808	Best use C<AnyEvent::post_detect { BLOCK }> instead.	993	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		994	it, as it takes care of these details.
		995
		996	This variable is mainly useful for modules that can do something useful
		997	when AnyEvent is used and thus want to know when it is initialised, but do
		998	not need to even load it by default. This array provides the means to hook
		999	into AnyEvent passively, without loading it.
		1000
		1001	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1002	together, you could put this into Coro (this is the actual code used by
		1003	Coro to accomplish this):
		1004
		1005	if (defined $AnyEvent::MODEL) {
		1006	# AnyEvent already initialised, so load Coro::AnyEvent
		1007	require Coro::AnyEvent;
		1008	} else {
		1009	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1010	# as soon as it is
		1011	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1012	}
809		1013
810	=back	1014	=back
811		1015
812	=head1 WHAT TO DO IN A MODULE	1016	=head1 WHAT TO DO IN A MODULE
813		1017
…		…
868		1072
869		1073
870	=head1 OTHER MODULES	1074	=head1 OTHER MODULES
871		1075
872	The following is a non-exhaustive list of additional modules that use	1076	The following is a non-exhaustive list of additional modules that use
873	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1077	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
874	in the same program. Some of the modules come with AnyEvent, some are	1078	modules and other event loops in the same program. Some of the modules
875	available via CPAN.	1079	come as part of AnyEvent, the others are available via CPAN.
876		1080
877	=over 4	1081	=over 4
878		1082
879	=item L<AnyEvent::Util>	1083	=item L<AnyEvent::Util>
880		1084
…		…
889		1093
890	=item L<AnyEvent::Handle>	1094	=item L<AnyEvent::Handle>
891		1095
892	Provide read and write buffers, manages watchers for reads and writes,	1096	Provide read and write buffers, manages watchers for reads and writes,
893	supports raw and formatted I/O, I/O queued and fully transparent and	1097	supports raw and formatted I/O, I/O queued and fully transparent and
894	non-blocking SSL/TLS.	1098	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
895		1099
896	=item L<AnyEvent::DNS>	1100	=item L<AnyEvent::DNS>
897		1101
898	Provides rich asynchronous DNS resolver capabilities.	1102	Provides rich asynchronous DNS resolver capabilities.
899		1103
		1104	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1105
		1106	Implement event-based interfaces to the protocols of the same name (for
		1107	the curious, IGS is the International Go Server and FCP is the Freenet
		1108	Client Protocol).
		1109
		1110	=item L<AnyEvent::Handle::UDP>
		1111
		1112	Here be danger!
		1113
		1114	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1115	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1116	it's use of a stream-based API with a protocol that isn't streamable, that
		1117	the only way to improve it is to delete it.
		1118
		1119	It features data corruption (but typically only under load) and general
		1120	confusion. On top, the author is not only clueless about UDP but also
		1121	fact-resistant - some gems of his understanding: "connect doesn't work
		1122	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1123	packets", "I don't need to implement proper error checking as UDP doesn't
		1124	support error checking" and so on - he doesn't even understand what's
		1125	wrong with his module when it is explained to him.
		1126
900	=item L<AnyEvent::HTTP>	1127	=item L<AnyEvent::DBI>
901		1128
902	A simple-to-use HTTP library that is capable of making a lot of concurrent	1129	Executes L<DBI> requests asynchronously in a proxy process for you,
903	HTTP requests.	1130	notifying you in an event-bnased way when the operation is finished.
		1131
		1132	=item L<AnyEvent::AIO>
		1133
		1134	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1135	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1136	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1137	file I/O, and much more.
904		1138
905	=item L<AnyEvent::HTTPD>	1139	=item L<AnyEvent::HTTPD>
906		1140
907	Provides a simple web application server framework.	1141	A simple embedded webserver.
908		1142
909	=item L<AnyEvent::FastPing>	1143	=item L<AnyEvent::FastPing>
910		1144
911	The fastest ping in the west.	1145	The fastest ping in the west.
912		1146
913	=item L<AnyEvent::DBI>
914
915	Executes L<DBI> requests asynchronously in a proxy process.
916
917	=item L<AnyEvent::AIO>
918
919	Truly asynchronous I/O, should be in the toolbox of every event
920	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
921	together.
922
923	=item L<AnyEvent::BDB>
924
925	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
926	L<BDB> and AnyEvent together.
927
928	=item L<AnyEvent::GPSD>
929
930	A non-blocking interface to gpsd, a daemon delivering GPS information.
931
932	=item L<AnyEvent::IGS>
933
934	A non-blocking interface to the Internet Go Server protocol (used by
935	L<App::IGS>).
936
937	=item L<AnyEvent::IRC>
938
939	AnyEvent based IRC client module family (replacing the older Net::IRC3).
940
941	=item L<Net::XMPP2>
942
943	AnyEvent based XMPP (Jabber protocol) module family.
944
945	=item L<Net::FCP>
946
947	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
948	of AnyEvent.
949
950	=item L<Event::ExecFlow>
951
952	High level API for event-based execution flow control.
953
954	=item L<Coro>	1147	=item L<Coro>
955		1148
956	Has special support for AnyEvent via L<Coro::AnyEvent>.	1149	Has special support for AnyEvent via L<Coro::AnyEvent>.
957		1150
958	=item L<IO::Lambda>
959
960	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
961
962	=back	1151	=back
963		1152
964	=cut	1153	=cut
965		1154
966	package AnyEvent;	1155	package AnyEvent;
967		1156
968	no warnings;	1157	# basically a tuned-down version of common::sense
969	use strict qw(vars subs);	1158	sub common_sense {
		1159	# from common:.sense 1.0
		1160	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
		1161	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1162	$^H |= 0x00000600;
		1163	}
970		1164
		1165	BEGIN { AnyEvent::common_sense }
		1166
971	use Carp;	1167	use Carp ();
972		1168
973	our $VERSION = 4.45;	1169	our $VERSION = '5.271';
974	our $MODEL;	1170	our $MODEL;
975		1171
976	our $AUTOLOAD;	1172	our $AUTOLOAD;
977	our @ISA;	1173	our @ISA;
978		1174
979	our @REGISTRY;	1175	our @REGISTRY;
980		1176
981	our $WIN32;	1177	our $VERBOSE;
982		1178
983	BEGIN {	1179	BEGIN {
984	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1180	require "AnyEvent/constants.pl";
		1181
985	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1182	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
986		1183
987	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1184	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
988	if ${^TAINT};	1185	if ${^TAINT};
989	}
990		1186
991	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1187	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1188
		1189	}
		1190
		1191	our $MAX_SIGNAL_LATENCY = 10;
992		1192
993	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1193	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
994		1194
995	{	1195	{
996	my $idx;	1196	my $idx;
…		…
998	for reverse split /\s*,\s*/,	1198	for reverse split /\s*,\s*/,
999	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1199	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1000	}	1200	}
1001		1201
1002	my @models = (	1202	my @models = (
1003	[EV:: => AnyEvent::Impl::EV::],	1203	[EV:: => AnyEvent::Impl::EV:: , 1],
1004	[Event:: => AnyEvent::Impl::Event::],
1005	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1204	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1006	# everything below here will not be autoprobed	1205	# everything below here will not (normally) be autoprobed
1007	# as the pureperl backend should work everywhere	1206	# as the pureperl backend should work everywhere
1008	# and is usually faster	1207	# and is usually faster
		1208	[Event:: => AnyEvent::Impl::Event::, 1],
		1209	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1210	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1211	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1009	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1212	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1010	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
1011	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1012	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1213	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1013	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1214	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1014	[Wx:: => AnyEvent::Impl::POE::],	1215	[Wx:: => AnyEvent::Impl::POE::],
1015	[Prima:: => AnyEvent::Impl::POE::],	1216	[Prima:: => AnyEvent::Impl::POE::],
1016	# IO::Async is just too broken - we would need workaorunds for its	1217	# IO::Async is just too broken - we would need workarounds for its
1017	# byzantine signal and broken child handling, among others.	1218	# byzantine signal and broken child handling, among others.
1018	# IO::Async is rather hard to detect, as it doesn't have any	1219	# IO::Async is rather hard to detect, as it doesn't have any
1019	# obvious default class.	1220	# obvious default class.
1020	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program	1221	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1021	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program	1222	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1022	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program	1223	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1224	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1023	);	1225	);
1024		1226
1025	our %method = map +($_ => 1),	1227	our %method = map +($_ => 1),
1026	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1228	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
1027		1229
1028	our @post_detect;	1230	our @post_detect;
1029		1231
1030	sub post_detect(&) {	1232	sub post_detect(&) {
1031	my ($cb) = @_;	1233	my ($cb) = @_;
1032		1234
1033	if ($MODEL) {
1034	$cb->();
1035
1036	1
1037	} else {
1038	push @post_detect, $cb;	1235	push @post_detect, $cb;
1039		1236
1040	defined wantarray	1237	defined wantarray
1041	? bless \$cb, "AnyEvent::Util::postdetect"	1238	? bless \$cb, "AnyEvent::Util::postdetect"
1042	: ()	1239	: ()
1043	}
1044	}	1240	}
1045		1241
1046	sub AnyEvent::Util::postdetect::DESTROY {	1242	sub AnyEvent::Util::postdetect::DESTROY {
1047	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1243	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1048	}	1244	}
1049		1245
1050	sub detect() {	1246	sub detect() {
		1247	# free some memory
		1248	*detect = sub () { $MODEL };
		1249
		1250	local $!; # for good measure
		1251	local $SIG{__DIE__};
		1252
		1253	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1254	my $model = "AnyEvent::Impl::$1";
		1255	if (eval "require $model") {
		1256	$MODEL = $model;
		1257	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1258	} else {
		1259	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1260	}
		1261	}
		1262
		1263	# check for already loaded models
1051	unless ($MODEL) {	1264	unless ($MODEL) {
1052	no strict 'refs';	1265	for (@REGISTRY, @models) {
1053	local $SIG{__DIE__};	1266	my ($package, $model) = @$_;
1054		1267	if (${"$package\::VERSION"} > 0) {
1055	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1056	my $model = "AnyEvent::Impl::$1";
1057	if (eval "require $model") {	1268	if (eval "require $model") {
1058	$MODEL = $model;	1269	$MODEL = $model;
1059	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1270	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1060	} else {	1271	last;
1061	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1272	}
1062	}	1273	}
1063	}	1274	}
1064		1275
1065	# check for already loaded models
1066	unless ($MODEL) {	1276	unless ($MODEL) {
		1277	# try to autoload a model
1067	for (@REGISTRY, @models) {	1278	for (@REGISTRY, @models) {
1068	my ($package, $model) = @$_;	1279	my ($package, $model, $autoload) = @$_;
		1280	if (
		1281	$autoload
		1282	and eval "require $package"
1069	if (${"$package\::VERSION"} > 0) {	1283	and ${"$package\::VERSION"} > 0
1070	if (eval "require $model") {	1284	and eval "require $model"
		1285	) {
1071	$MODEL = $model;	1286	$MODEL = $model;
1072	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1287	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1073	last;	1288	last;
1074	}
1075	}	1289	}
1076	}	1290	}
1077		1291
1078	unless ($MODEL) {
1079	# try to load a model
1080
1081	for (@REGISTRY, @models) {
1082	my ($package, $model) = @$_;
1083	if (eval "require $package"
1084	and ${"$package\::VERSION"} > 0
1085	and eval "require $model") {
1086	$MODEL = $model;
1087	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1088	last;
1089	}
1090	}
1091
1092	$MODEL	1292	$MODEL
1093	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1293	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
1094	}
1095	}	1294	}
1096
1097	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1098
1099	unshift @ISA, $MODEL;
1100
1101	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1102
1103	(shift @post_detect)->() while @post_detect;
1104	}	1295	}
		1296
		1297	@models = (); # free probe data
		1298
		1299	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1300	unshift @ISA, $MODEL;
		1301
		1302	# now nuke some methods that are overriden by the backend.
		1303	# SUPER is not allowed.
		1304	for (qw(time signal child idle)) {
		1305	undef &{"AnyEvent::Base::$_"}
		1306	if defined &{"$MODEL\::$_"};
		1307	}
		1308
		1309	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1310
		1311	(shift @post_detect)->() while @post_detect;
		1312
		1313	*post_detect = sub(&) {
		1314	shift->();
		1315
		1316	undef
		1317	};
1105		1318
1106	$MODEL	1319	$MODEL
1107	}	1320	}
1108		1321
1109	sub AUTOLOAD {	1322	sub AUTOLOAD {
1110	(my $func = $AUTOLOAD) =~ s/.*://;	1323	(my $func = $AUTOLOAD) =~ s/.*://;
1111		1324
1112	$method{$func}	1325	$method{$func}
1113	or croak "$func: not a valid method for AnyEvent objects";	1326	or Carp::croak "$func: not a valid AnyEvent class method";
1114		1327
1115	detect unless $MODEL;	1328	detect;
1116		1329
1117	my $class = shift;	1330	my $class = shift;
1118	$class->$func (@_);	1331	$class->$func (@_);
1119	}	1332	}
1120		1333
…		…
1123	# allow only one watcher per fd, so we dup it to get a different one).	1336	# allow only one watcher per fd, so we dup it to get a different one).
1124	sub _dupfh($$;$$) {	1337	sub _dupfh($$;$$) {
1125	my ($poll, $fh, $r, $w) = @_;	1338	my ($poll, $fh, $r, $w) = @_;
1126		1339
1127	# cygwin requires the fh mode to be matching, unix doesn't	1340	# cygwin requires the fh mode to be matching, unix doesn't
1128	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1341	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1129	: $poll eq "w" ? ($w, ">")
1130	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1131		1342
1132	open my $fh2, "$mode&" . fileno $fh	1343	open my $fh2, $mode, $fh
1133	or die "cannot dup() filehandle: $!,";	1344	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1134		1345
1135	# we assume CLOEXEC is already set by perl in all important cases	1346	# we assume CLOEXEC is already set by perl in all important cases
1136		1347
1137	($fh2, $rw)	1348	($fh2, $rw)
1138	}	1349	}
1139		1350
		1351	=head1 SIMPLIFIED AE API
		1352
		1353	Starting with version 5.0, AnyEvent officially supports a second, much
		1354	simpler, API that is designed to reduce the calling, typing and memory
		1355	overhead by using function call syntax and a fixed number of parameters.
		1356
		1357	See the L<AE> manpage for details.
		1358
		1359	=cut
		1360
		1361	package AE;
		1362
		1363	our $VERSION = $AnyEvent::VERSION;
		1364
		1365	# fall back to the main API by default - backends and AnyEvent::Base
		1366	# implementations can overwrite these.
		1367
		1368	sub io($$$) {
		1369	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1370	}
		1371
		1372	sub timer($$$) {
		1373	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1374	}
		1375
		1376	sub signal($$) {
		1377	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1378	}
		1379
		1380	sub child($$) {
		1381	AnyEvent->child (pid => $_[0], cb => $_[1])
		1382	}
		1383
		1384	sub idle($) {
		1385	AnyEvent->idle (cb => $_[0])
		1386	}
		1387
		1388	sub cv(;&) {
		1389	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1390	}
		1391
		1392	sub now() {
		1393	AnyEvent->now
		1394	}
		1395
		1396	sub now_update() {
		1397	AnyEvent->now_update
		1398	}
		1399
		1400	sub time() {
		1401	AnyEvent->time
		1402	}
		1403
1140	package AnyEvent::Base;	1404	package AnyEvent::Base;
1141		1405
1142	# default implementations for many methods	1406	# default implementations for many methods
1143		1407
1144	BEGIN {	1408	sub time {
		1409	eval q{ # poor man's autoloading {}
		1410	# probe for availability of Time::HiRes
1145	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1411	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1412	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1146	*_time = \&Time::HiRes::time;	1413	*AE::time = \&Time::HiRes::time;
1147	# if (eval "use POSIX (); (POSIX::times())...	1414	# if (eval "use POSIX (); (POSIX::times())...
1148	} else {	1415	} else {
		1416	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1149	*_time = sub { time }; # epic fail	1417	*AE::time = sub (){ time }; # epic fail
		1418	}
		1419
		1420	*time = sub { AE::time }; # different prototypes
		1421	};
		1422	die if $@;
		1423
		1424	&time
		1425	}
		1426
		1427	*now = \&time;
		1428
		1429	sub now_update { }
		1430
		1431	# default implementation for ->condvar
		1432
		1433	sub condvar {
		1434	eval q{ # poor man's autoloading {}
		1435	*condvar = sub {
		1436	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1437	};
		1438
		1439	*AE::cv = sub (;&) {
		1440	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1441	};
		1442	};
		1443	die if $@;
		1444
		1445	&condvar
		1446	}
		1447
		1448	# default implementation for ->signal
		1449
		1450	our $HAVE_ASYNC_INTERRUPT;
		1451
		1452	sub _have_async_interrupt() {
		1453	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1454	&& eval "use Async::Interrupt 1.02 (); 1")
		1455	unless defined $HAVE_ASYNC_INTERRUPT;
		1456
		1457	$HAVE_ASYNC_INTERRUPT
		1458	}
		1459
		1460	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1461	our (%SIG_ASY, %SIG_ASY_W);
		1462	our ($SIG_COUNT, $SIG_TW);
		1463
		1464	# install a dummy wakeup watcher to reduce signal catching latency
		1465	# used by Impls
		1466	sub _sig_add() {
		1467	unless ($SIG_COUNT++) {
		1468	# try to align timer on a full-second boundary, if possible
		1469	my $NOW = AE::now;
		1470
		1471	$SIG_TW = AE::timer
		1472	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1473	$MAX_SIGNAL_LATENCY,
		1474	sub { } # just for the PERL_ASYNC_CHECK
		1475	;
1150	}	1476	}
1151	}	1477	}
1152		1478
1153	sub time { _time }	1479	sub _sig_del {
1154	sub now { _time }	1480	undef $SIG_TW
1155	sub now_update { }	1481	unless --$SIG_COUNT;
1156
1157	# default implementation for ->condvar
1158
1159	sub condvar {
1160	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1161	}	1482	}
1162		1483
1163	# default implementation for ->signal	1484	our $_sig_name_init; $_sig_name_init = sub {
		1485	eval q{ # poor man's autoloading {}
		1486	undef $_sig_name_init;
1164		1487
1165	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1488	if (_have_async_interrupt) {
		1489	*sig2num = \&Async::Interrupt::sig2num;
		1490	*sig2name = \&Async::Interrupt::sig2name;
		1491	} else {
		1492	require Config;
1166		1493
1167	sub _signal_exec {	1494	my %signame2num;
1168	sysread $SIGPIPE_R, my $dummy, 4;	1495	@signame2num{ split ' ', $Config::Config{sig_name} }
		1496	= split ' ', $Config::Config{sig_num};
1169		1497
1170	while (%SIG_EV) {	1498	my @signum2name;
1171	for (keys %SIG_EV) {	1499	@signum2name[values %signame2num] = keys %signame2num;
1172	delete $SIG_EV{$_};	1500
1173	$_->() for values %{ $SIG_CB{$_} || {} };	1501	*sig2num = sub($) {
		1502	$_[0] > 0 ? shift : $signame2num{+shift}
		1503	};
		1504	*sig2name = sub ($) {
		1505	$_[0] > 0 ? $signum2name[+shift] : shift
		1506	};
1174	}	1507	}
1175	}	1508	};
1176	}	1509	die if $@;
		1510	};
		1511
		1512	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1513	sub sig2name($) { &$_sig_name_init; &sig2name }
1177		1514
1178	sub signal {	1515	sub signal {
1179	my (undef, %arg) = @_;	1516	eval q{ # poor man's autoloading {}
		1517	# probe for availability of Async::Interrupt
		1518	if (_have_async_interrupt) {
		1519	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1180		1520
1181	unless ($SIGPIPE_R) {	1521	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1182	require Fcntl;	1522	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1183		1523
1184	if (AnyEvent::WIN32) {
1185	require AnyEvent::Util;
1186
1187	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1188	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1189	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1190	} else {	1524	} else {
		1525	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1526
		1527	if (AnyEvent::WIN32) {
		1528	require AnyEvent::Util;
		1529
		1530	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1531	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1532	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1533	} else {
1191	pipe $SIGPIPE_R, $SIGPIPE_W;	1534	pipe $SIGPIPE_R, $SIGPIPE_W;
1192	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1535	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1193	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1536	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1194		1537
1195	# not strictly required, as $^F is normally 2, but let's make sure...	1538	# not strictly required, as $^F is normally 2, but let's make sure...
1196	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1539	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1197	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1540	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1541	}
		1542
		1543	$SIGPIPE_R
		1544	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1545
		1546	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1198	}	1547	}
1199		1548
1200	$SIGPIPE_R	1549	*signal = $HAVE_ASYNC_INTERRUPT
1201	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1550	? sub {
		1551	my (undef, %arg) = @_;
1202		1552
1203	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1553	# async::interrupt
1204	}
1205
1206	my $signal = uc $arg{signal}	1554	my $signal = sig2num $arg{signal};
1207	or Carp::croak "required option 'signal' is missing";
1208
1209	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1555	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1556
		1557	$SIG_ASY{$signal} ||= new Async::Interrupt
		1558	cb => sub { undef $SIG_EV{$signal} },
		1559	signal => $signal,
		1560	pipe => [$SIGPIPE_R->filenos],
		1561	pipe_autodrain => 0,
		1562	;
		1563
		1564	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1565	}
		1566	: sub {
		1567	my (undef, %arg) = @_;
		1568
		1569	# pure perl
		1570	my $signal = sig2name $arg{signal};
		1571	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1572
1210	$SIG{$signal} ||= sub {	1573	$SIG{$signal} ||= sub {
1211	local $!;	1574	local $!;
1212	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1575	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1213	undef $SIG_EV{$signal};	1576	undef $SIG_EV{$signal};
		1577	};
		1578
		1579	# can't do signal processing without introducing races in pure perl,
		1580	# so limit the signal latency.
		1581	_sig_add;
		1582
		1583	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1584	}
		1585	;
		1586
		1587	*AnyEvent::Base::signal::DESTROY = sub {
		1588	my ($signal, $cb) = @{$_[0]};
		1589
		1590	_sig_del;
		1591
		1592	delete $SIG_CB{$signal}{$cb};
		1593
		1594	$HAVE_ASYNC_INTERRUPT
		1595	? delete $SIG_ASY{$signal}
		1596	: # delete doesn't work with older perls - they then
		1597	# print weird messages, or just unconditionally exit
		1598	# instead of getting the default action.
		1599	undef $SIG{$signal}
		1600	unless keys %{ $SIG_CB{$signal} };
		1601	};
		1602
		1603	*_signal_exec = sub {
		1604	$HAVE_ASYNC_INTERRUPT
		1605	? $SIGPIPE_R->drain
		1606	: sysread $SIGPIPE_R, (my $dummy), 9;
		1607
		1608	while (%SIG_EV) {
		1609	for (keys %SIG_EV) {
		1610	delete $SIG_EV{$_};
		1611	$_->() for values %{ $SIG_CB{$_} || {} };
		1612	}
		1613	}
		1614	};
1214	};	1615	};
		1616	die if $@;
1215		1617
1216	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1618	&signal
1217	}
1218
1219	sub AnyEvent::Base::signal::DESTROY {
1220	my ($signal, $cb) = @{$_[0]};
1221
1222	delete $SIG_CB{$signal}{$cb};
1223
1224	# delete doesn't work with older perls - they then
1225	# print weird messages, or just unconditionally exit
1226	# instead of getting the default action.
1227	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1228	}	1619	}
1229		1620
1230	# default implementation for ->child	1621	# default implementation for ->child
1231		1622
1232	our %PID_CB;	1623	our %PID_CB;
1233	our $CHLD_W;	1624	our $CHLD_W;
1234	our $CHLD_DELAY_W;	1625	our $CHLD_DELAY_W;
1235	our $WNOHANG;	1626	our $WNOHANG;
1236		1627
1237	sub _sigchld {	1628	# used by many Impl's
1238	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1629	sub _emit_childstatus($$) {
		1630	my (undef, $rpid, $rstatus) = @_;
		1631
		1632	$_->($rpid, $rstatus)
1239	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1633	for values %{ $PID_CB{$rpid} || {} },
1240	(values %{ $PID_CB{0} || {} });	1634	values %{ $PID_CB{0} || {} };
1241	}
1242	}	1635	}
1243		1636
1244	sub child {	1637	sub child {
		1638	eval q{ # poor man's autoloading {}
		1639	*_sigchld = sub {
		1640	my $pid;
		1641
		1642	AnyEvent->_emit_childstatus ($pid, $?)
		1643	while ($pid = waitpid -1, $WNOHANG) > 0;
		1644	};
		1645
		1646	*child = sub {
1245	my (undef, %arg) = @_;	1647	my (undef, %arg) = @_;
1246		1648
1247	defined (my $pid = $arg{pid} + 0)	1649	defined (my $pid = $arg{pid} + 0)
1248	or Carp::croak "required option 'pid' is missing";	1650	or Carp::croak "required option 'pid' is missing";
1249		1651
1250	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1652	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1251		1653
		1654	# WNOHANG is almost cetrainly 1 everywhere
		1655	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1656	? 1
1252	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1657	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1253		1658
1254	unless ($CHLD_W) {	1659	unless ($CHLD_W) {
1255	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1660	$CHLD_W = AE::signal CHLD => \&_sigchld;
1256	# child could be a zombie already, so make at least one round	1661	# child could be a zombie already, so make at least one round
1257	&_sigchld;	1662	&_sigchld;
1258	}	1663	}
1259		1664
1260	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1665	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1261	}	1666	};
1262		1667
1263	sub AnyEvent::Base::child::DESTROY {	1668	*AnyEvent::Base::child::DESTROY = sub {
1264	my ($pid, $cb) = @{$_[0]};	1669	my ($pid, $cb) = @{$_[0]};
1265		1670
1266	delete $PID_CB{$pid}{$cb};	1671	delete $PID_CB{$pid}{$cb};
1267	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1672	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1268		1673
1269	undef $CHLD_W unless keys %PID_CB;	1674	undef $CHLD_W unless keys %PID_CB;
		1675	};
		1676	};
		1677	die if $@;
		1678
		1679	&child
1270	}	1680	}
1271		1681
1272	# idle emulation is done by simply using a timer, regardless	1682	# idle emulation is done by simply using a timer, regardless
1273	# of whether the process is idle or not, and not letting	1683	# of whether the process is idle or not, and not letting
1274	# the callback use more than 50% of the time.	1684	# the callback use more than 50% of the time.
1275	sub idle {	1685	sub idle {
		1686	eval q{ # poor man's autoloading {}
		1687	*idle = sub {
1276	my (undef, %arg) = @_;	1688	my (undef, %arg) = @_;
1277		1689
1278	my ($cb, $w, $rcb) = $arg{cb};	1690	my ($cb, $w, $rcb) = $arg{cb};
1279		1691
1280	$rcb = sub {	1692	$rcb = sub {
1281	if ($cb) {	1693	if ($cb) {
1282	$w = _time;	1694	$w = _time;
1283	&$cb;	1695	&$cb;
1284	$w = _time - $w;	1696	$w = _time - $w;
1285		1697
1286	# never use more then 50% of the time for the idle watcher,	1698	# never use more then 50% of the time for the idle watcher,
1287	# within some limits	1699	# within some limits
1288	$w = 0.0001 if $w < 0.0001;	1700	$w = 0.0001 if $w < 0.0001;
1289	$w = 5 if $w > 5;	1701	$w = 5 if $w > 5;
1290		1702
1291	$w = AnyEvent->timer (after => $w, cb => $rcb);	1703	$w = AE::timer $w, 0, $rcb;
1292	} else {	1704	} else {
1293	# clean up...	1705	# clean up...
1294	undef $w;	1706	undef $w;
1295	undef $rcb;	1707	undef $rcb;
		1708	}
		1709	};
		1710
		1711	$w = AE::timer 0.05, 0, $rcb;
		1712
		1713	bless \\$cb, "AnyEvent::Base::idle"
1296	}	1714	};
		1715
		1716	*AnyEvent::Base::idle::DESTROY = sub {
		1717	undef $${$_[0]};
		1718	};
1297	};	1719	};
		1720	die if $@;
1298		1721
1299	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1722	&idle
1300
1301	bless \\$cb, "AnyEvent::Base::idle"
1302	}
1303
1304	sub AnyEvent::Base::idle::DESTROY {
1305	undef $${$_[0]};
1306	}	1723	}
1307		1724
1308	package AnyEvent::CondVar;	1725	package AnyEvent::CondVar;
1309		1726
1310	our @ISA = AnyEvent::CondVar::Base::;	1727	our @ISA = AnyEvent::CondVar::Base::;
1311		1728
1312	package AnyEvent::CondVar::Base;	1729	package AnyEvent::CondVar::Base;
1313		1730
1314	use overload	1731	#use overload
1315	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1732	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1316	fallback => 1;	1733	# fallback => 1;
		1734
		1735	# save 300+ kilobytes by dirtily hardcoding overloading
		1736	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1737	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1738	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1739	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1740
		1741	our $WAITING;
1317		1742
1318	sub _send {	1743	sub _send {
1319	# nop	1744	# nop
1320	}	1745	}
1321		1746
…		…
1334	sub ready {	1759	sub ready {
1335	$_[0]{_ae_sent}	1760	$_[0]{_ae_sent}
1336	}	1761	}
1337		1762
1338	sub _wait {	1763	sub _wait {
		1764	$WAITING
		1765	and !$_[0]{_ae_sent}
		1766	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1767
		1768	local $WAITING = 1;
1339	AnyEvent->one_event while !$_[0]{_ae_sent};	1769	AnyEvent->one_event while !$_[0]{_ae_sent};
1340	}	1770	}
1341		1771
1342	sub recv {	1772	sub recv {
1343	$_[0]->_wait;	1773	$_[0]->_wait;
…		…
1345	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1775	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1346	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1776	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1347	}	1777	}
1348		1778
1349	sub cb {	1779	sub cb {
1350	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1780	my $cv = shift;
		1781
		1782	@_
		1783	and $cv->{_ae_cb} = shift
		1784	and $cv->{_ae_sent}
		1785	and (delete $cv->{_ae_cb})->($cv);
		1786
1351	$_[0]{_ae_cb}	1787	$cv->{_ae_cb}
1352	}	1788	}
1353		1789
1354	sub begin {	1790	sub begin {
1355	++$_[0]{_ae_counter};	1791	++$_[0]{_ae_counter};
1356	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1792	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1405	C<PERL_ANYEVENT_MODEL>.	1841	C<PERL_ANYEVENT_MODEL>.
1406		1842
1407	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1843	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1408	model it chooses.	1844	model it chooses.
1409		1845
		1846	When set to C<8> or higher, then AnyEvent will report extra information on
		1847	which optional modules it loads and how it implements certain features.
		1848
1410	=item C<PERL_ANYEVENT_STRICT>	1849	=item C<PERL_ANYEVENT_STRICT>
1411		1850
1412	AnyEvent does not do much argument checking by default, as thorough	1851	AnyEvent does not do much argument checking by default, as thorough
1413	argument checking is very costly. Setting this variable to a true value	1852	argument checking is very costly. Setting this variable to a true value
1414	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1853	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1415	check the arguments passed to most method calls. If it finds any problems,	1854	check the arguments passed to most method calls. If it finds any problems,
1416	it will croak.	1855	it will croak.
1417		1856
1418	In other words, enables "strict" mode.	1857	In other words, enables "strict" mode.
1419		1858
1420	Unlike C<use strict>, it is definitely recommended to keep it off in	1859	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1421	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1860	>>, it is definitely recommended to keep it off in production. Keeping
1422	developing programs can be very useful, however.	1861	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1862	can be very useful, however.
1423		1863
1424	=item C<PERL_ANYEVENT_MODEL>	1864	=item C<PERL_ANYEVENT_MODEL>
1425		1865
1426	This can be used to specify the event model to be used by AnyEvent, before	1866	This can be used to specify the event model to be used by AnyEvent, before
1427	auto detection and -probing kicks in. It must be a string consisting	1867	auto detection and -probing kicks in. It must be a string consisting
…		…
1470		1910
1471	=item C<PERL_ANYEVENT_MAX_FORKS>	1911	=item C<PERL_ANYEVENT_MAX_FORKS>
1472		1912
1473	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1913	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1474	will create in parallel.	1914	will create in parallel.
		1915
		1916	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1917
		1918	The default value for the C<max_outstanding> parameter for the default DNS
		1919	resolver - this is the maximum number of parallel DNS requests that are
		1920	sent to the DNS server.
		1921
		1922	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1923
		1924	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1925	configuration) in the default resolver. When set to the empty string, no
		1926	default config will be used.
		1927
		1928	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1929
		1930	When neither C<ca_file> nor C<ca_path> was specified during
		1931	L<AnyEvent::TLS> context creation, and either of these environment
		1932	variables exist, they will be used to specify CA certificate locations
		1933	instead of a system-dependent default.
		1934
		1935	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1936
		1937	When these are set to C<1>, then the respective modules are not
		1938	loaded. Mostly good for testing AnyEvent itself.
1475		1939
1476	=back	1940	=back
1477		1941
1478	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1942	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1479		1943
…		…
1537	warn "read: $input\n"; # output what has been read	2001	warn "read: $input\n"; # output what has been read
1538	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2002	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1539	},	2003	},
1540	);	2004	);
1541		2005
1542	my $time_watcher; # can only be used once
1543
1544	sub new_timer {
1545	$timer = AnyEvent->timer (after => 1, cb => sub {	2006	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1546	warn "timeout\n"; # print 'timeout' about every second	2007	warn "timeout\n"; # print 'timeout' at most every second
1547	&new_timer; # and restart the time
1548	});	2008	});
1549	}
1550
1551	new_timer; # create first timer
1552		2009
1553	$cv->recv; # wait until user enters /^q/i	2010	$cv->recv; # wait until user enters /^q/i
1554		2011
1555	=head1 REAL-WORLD EXAMPLE	2012	=head1 REAL-WORLD EXAMPLE
1556		2013
…		…
1629		2086
1630	The actual code goes further and collects all errors (C<die>s, exceptions)	2087	The actual code goes further and collects all errors (C<die>s, exceptions)
1631	that occurred during request processing. The C<result> method detects	2088	that occurred during request processing. The C<result> method detects
1632	whether an exception as thrown (it is stored inside the $txn object)	2089	whether an exception as thrown (it is stored inside the $txn object)
1633	and just throws the exception, which means connection errors and other	2090	and just throws the exception, which means connection errors and other
1634	problems get reported tot he code that tries to use the result, not in a	2091	problems get reported to the code that tries to use the result, not in a
1635	random callback.	2092	random callback.
1636		2093
1637	All of this enables the following usage styles:	2094	All of this enables the following usage styles:
1638		2095
1639	1. Blocking:	2096	1. Blocking:
…		…
1687	through AnyEvent. The benchmark creates a lot of timers (with a zero	2144	through AnyEvent. The benchmark creates a lot of timers (with a zero
1688	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2145	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1689	which it is), lets them fire exactly once and destroys them again.	2146	which it is), lets them fire exactly once and destroys them again.
1690		2147
1691	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2148	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1692	distribution.	2149	distribution. It uses the L<AE> interface, which makes a real difference
		2150	for the EV and Perl backends only.
1693		2151
1694	=head3 Explanation of the columns	2152	=head3 Explanation of the columns
1695		2153
1696	I<watcher> is the number of event watchers created/destroyed. Since	2154	I<watcher> is the number of event watchers created/destroyed. Since
1697	different event models feature vastly different performances, each event	2155	different event models feature vastly different performances, each event
…		…
1718	watcher.	2176	watcher.
1719		2177
1720	=head3 Results	2178	=head3 Results
1721		2179
1722	name watchers bytes create invoke destroy comment	2180	name watchers bytes create invoke destroy comment
1723	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2181	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1724	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2182	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1725	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2183	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1726	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2184	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1727	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2185	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1728	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2186	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1729	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2187	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1730	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2188	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1731	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2189	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1732	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2190	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1733	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2191	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1734	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2192	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1735		2193
1736	=head3 Discussion	2194	=head3 Discussion
1737		2195
1738	The benchmark does I<not> measure scalability of the event loop very	2196	The benchmark does I<not> measure scalability of the event loop very
1739	well. For example, a select-based event loop (such as the pure perl one)	2197	well. For example, a select-based event loop (such as the pure perl one)
…		…
1751	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2209	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1752	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2210	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1753	cycles with POE.	2211	cycles with POE.
1754		2212
1755	C<EV> is the sole leader regarding speed and memory use, which are both	2213	C<EV> is the sole leader regarding speed and memory use, which are both
1756	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2214	maximal/minimal, respectively. When using the L<AE> API there is zero
		2215	overhead (when going through the AnyEvent API create is about 5-6 times
		2216	slower, with other times being equal, so still uses far less memory than
1757	far less memory than any other event loop and is still faster than Event	2217	any other event loop and is still faster than Event natively).
1758	natively.
1759		2218
1760	The pure perl implementation is hit in a few sweet spots (both the	2219	The pure perl implementation is hit in a few sweet spots (both the
1761	constant timeout and the use of a single fd hit optimisations in the perl	2220	constant timeout and the use of a single fd hit optimisations in the perl
1762	interpreter and the backend itself). Nevertheless this shows that it	2221	interpreter and the backend itself). Nevertheless this shows that it
1763	adds very little overhead in itself. Like any select-based backend its	2222	adds very little overhead in itself. Like any select-based backend its
…		…
1837	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2296	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1838	(1%) are active. This mirrors the activity of large servers with many	2297	(1%) are active. This mirrors the activity of large servers with many
1839	connections, most of which are idle at any one point in time.	2298	connections, most of which are idle at any one point in time.
1840		2299
1841	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2300	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1842	distribution.	2301	distribution. It uses the L<AE> interface, which makes a real difference
		2302	for the EV and Perl backends only.
1843		2303
1844	=head3 Explanation of the columns	2304	=head3 Explanation of the columns
1845		2305
1846	I<sockets> is the number of sockets, and twice the number of "servers" (as	2306	I<sockets> is the number of sockets, and twice the number of "servers" (as
1847	each server has a read and write socket end).	2307	each server has a read and write socket end).
…		…
1855	a new one that moves the timeout into the future.	2315	a new one that moves the timeout into the future.
1856		2316
1857	=head3 Results	2317	=head3 Results
1858		2318
1859	name sockets create request	2319	name sockets create request
1860	EV 20000 69.01 11.16	2320	EV 20000 62.66 7.99
1861	Perl 20000 73.32 35.87	2321	Perl 20000 68.32 32.64
1862	IOAsync 20000 157.00 98.14 epoll	2322	IOAsync 20000 174.06 101.15 epoll
1863	IOAsync 20000 159.31 616.06 poll	2323	IOAsync 20000 174.67 610.84 poll
1864	Event 20000 212.62 257.32	2324	Event 20000 202.69 242.91
1865	Glib 20000 651.16 1896.30	2325	Glib 20000 557.01 1689.52
1866	POE 20000 349.67 12317.24 uses POE::Loop::Event	2326	POE 20000 341.54 12086.32 uses POE::Loop::Event
1867		2327
1868	=head3 Discussion	2328	=head3 Discussion
1869		2329
1870	This benchmark I<does> measure scalability and overall performance of the	2330	This benchmark I<does> measure scalability and overall performance of the
1871	particular event loop.	2331	particular event loop.
…		…
1997	As you can see, the AnyEvent + EV combination even beats the	2457	As you can see, the AnyEvent + EV combination even beats the
1998	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2458	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
1999	backend easily beats IO::Lambda and POE.	2459	backend easily beats IO::Lambda and POE.
2000		2460
2001	And even the 100% non-blocking version written using the high-level (and	2461	And even the 100% non-blocking version written using the high-level (and
2002	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2462	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2003	large margin, even though it does all of DNS, tcp-connect and socket I/O	2463	higher level ("unoptimised") abstractions by a large margin, even though
2004	in a non-blocking way.	2464	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2005		2465
2006	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2466	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2007	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2467	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2008	part of the IO::lambda distribution and were used without any changes.	2468	part of the IO::Lambda distribution and were used without any changes.
2009		2469
2010		2470
2011	=head1 SIGNALS	2471	=head1 SIGNALS
2012		2472
2013	AnyEvent currently installs handlers for these signals:	2473	AnyEvent currently installs handlers for these signals:
…		…
2018		2478
2019	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2479	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
2020	emulation for event loops that do not support them natively. Also, some	2480	emulation for event loops that do not support them natively. Also, some
2021	event loops install a similar handler.	2481	event loops install a similar handler.
2022		2482
2023	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will	2483	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2024	reset it to default, to avoid losing child exit statuses.	2484	AnyEvent will reset it to default, to avoid losing child exit statuses.
2025		2485
2026	=item SIGPIPE	2486	=item SIGPIPE
2027		2487
2028	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2488	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
2029	when AnyEvent gets loaded.	2489	when AnyEvent gets loaded.
…		…
2047	if $SIG{CHLD} eq 'IGNORE';	2507	if $SIG{CHLD} eq 'IGNORE';
2048		2508
2049	$SIG{PIPE} = sub { }	2509	$SIG{PIPE} = sub { }
2050	unless defined $SIG{PIPE};	2510	unless defined $SIG{PIPE};
2051		2511
		2512	=head1 RECOMMENDED/OPTIONAL MODULES
		2513
		2514	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2515	it's built-in modules) are required to use it.
		2516
		2517	That does not mean that AnyEvent won't take advantage of some additional
		2518	modules if they are installed.
		2519
		2520	This section explains which additional modules will be used, and how they
		2521	affect AnyEvent's operation.
		2522
		2523	=over 4
		2524
		2525	=item L<Async::Interrupt>
		2526
		2527	This slightly arcane module is used to implement fast signal handling: To
		2528	my knowledge, there is no way to do completely race-free and quick
		2529	signal handling in pure perl. To ensure that signals still get
		2530	delivered, AnyEvent will start an interval timer to wake up perl (and
		2531	catch the signals) with some delay (default is 10 seconds, look for
		2532	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2533
		2534	If this module is available, then it will be used to implement signal
		2535	catching, which means that signals will not be delayed, and the event loop
		2536	will not be interrupted regularly, which is more efficient (and good for
		2537	battery life on laptops).
		2538
		2539	This affects not just the pure-perl event loop, but also other event loops
		2540	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2541
		2542	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2543	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2544	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2545	does nothing for those backends.
		2546
		2547	=item L<EV>
		2548
		2549	This module isn't really "optional", as it is simply one of the backend
		2550	event loops that AnyEvent can use. However, it is simply the best event
		2551	loop available in terms of features, speed and stability: It supports
		2552	the AnyEvent API optimally, implements all the watcher types in XS, does
		2553	automatic timer adjustments even when no monotonic clock is available,
		2554	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2555	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2556	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2557
		2558	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2559	then this module will do nothing for you.
		2560
		2561	=item L<Guard>
		2562
		2563	The guard module, when used, will be used to implement
		2564	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2565	lot less memory), but otherwise doesn't affect guard operation much. It is
		2566	purely used for performance.
		2567
		2568	=item L<JSON> and L<JSON::XS>
		2569
		2570	One of these modules is required when you want to read or write JSON data
		2571	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2572	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2573
		2574	=item L<Net::SSLeay>
		2575
		2576	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2577	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2578	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2579
		2580	=item L<Time::HiRes>
		2581
		2582	This module is part of perl since release 5.008. It will be used when the
		2583	chosen event library does not come with a timing source on it's own. The
		2584	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2585	try to use a monotonic clock for timing stability.
		2586
		2587	=back
		2588
		2589
2052	=head1 FORK	2590	=head1 FORK
2053		2591
2054	Most event libraries are not fork-safe. The ones who are usually are	2592	Most event libraries are not fork-safe. The ones who are usually are
2055	because they rely on inefficient but fork-safe C<select> or C<poll>	2593	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2056	calls. Only L<EV> is fully fork-aware.	2594	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2595	are usually badly thought-out hacks that are incompatible with fork in
		2596	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2597	continue event-processing in both parent and child (or both, if you know
		2598	what you are doing).
		2599
		2600	This means that, in general, you cannot fork and do event processing in
		2601	the child if the event library was initialised before the fork (which
		2602	usually happens when the first AnyEvent watcher is created, or the library
		2603	is loaded).
2057		2604
2058	If you have to fork, you must either do so I<before> creating your first	2605	If you have to fork, you must either do so I<before> creating your first
2059	watcher OR you must not use AnyEvent at all in the child.	2606	watcher OR you must not use AnyEvent at all in the child OR you must do
		2607	something completely out of the scope of AnyEvent.
		2608
		2609	The problem of doing event processing in the parent I<and> the child
		2610	is much more complicated: even for backends that I<are> fork-aware or
		2611	fork-safe, their behaviour is not usually what you want: fork clones all
		2612	watchers, that means all timers, I/O watchers etc. are active in both
		2613	parent and child, which is almost never what you want. USing C<exec>
		2614	to start worker children from some kind of manage rprocess is usually
		2615	preferred, because it is much easier and cleaner, at the expense of having
		2616	to have another binary.
2060		2617
2061		2618
2062	=head1 SECURITY CONSIDERATIONS	2619	=head1 SECURITY CONSIDERATIONS
2063		2620
2064	AnyEvent can be forced to load any event model via	2621	AnyEvent can be forced to load any event model via
…		…
2102	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2659	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2103		2660
2104	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2661	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2105	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2662	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2106	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2663	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2107	L<AnyEvent::Impl::POE>.	2664	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2108		2665
2109	Non-blocking file handles, sockets, TCP clients and	2666	Non-blocking file handles, sockets, TCP clients and
2110	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2667	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2111		2668
2112	Asynchronous DNS: L<AnyEvent::DNS>.	2669	Asynchronous DNS: L<AnyEvent::DNS>.
2113		2670
2114	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2671	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2672	L<Coro::Event>,
2115		2673
2116	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2674	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2675	L<AnyEvent::HTTP>.
2117		2676
2118		2677
2119	=head1 AUTHOR	2678	=head1 AUTHOR
2120		2679
2121	Marc Lehmann <schmorp@schmorp.de>	2680	Marc Lehmann <schmorp@schmorp.de>

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