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Revision 1.326 by root, Sun Jun 6 10:11:56 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, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
		6	and POE are various supported event loops/environments.
6		7
7	=head1 SYNOPSIS	8	=head1 SYNOPSIS
8		9
9	use AnyEvent;	10	use AnyEvent;
10		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
11	# file descriptor readable	15	# file handle or descriptor readable
12	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
13		17
14	# one-shot or repeating timers	18	# one-shot or repeating timers
15	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
16	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
…		…
39	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
40		44
41	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
42	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
43	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.
44		56
45	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	57	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
46		58
47	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
48	nowadays. So what is different about AnyEvent?	60	nowadays. So what is different about AnyEvent?
…		…
172	my variables are only visible after the statement in which they are	184	my variables are only visible after the statement in which they are
173	declared.	185	declared.
174		186
175	=head2 I/O WATCHERS	187	=head2 I/O WATCHERS
176		188
		189	$w = AnyEvent->io (
		190	fh => <filehandle_or_fileno>,
		191	poll => <"r" or "w">,
		192	cb => <callback>,
		193	);
		194
177	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	195	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
178	with the following mandatory key-value pairs as arguments:	196	with the following mandatory key-value pairs as arguments:
179		197
180	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch	198	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
181	for events (AnyEvent might or might not keep a reference to this file	199	for events (AnyEvent might or might not keep a reference to this file
182	handle). Note that only file handles pointing to things for which	200	handle). Note that only file handles pointing to things for which
183	non-blocking operation makes sense are allowed. This includes sockets,	201	non-blocking operation makes sense are allowed. This includes sockets,
184	most character devices, pipes, fifos and so on, but not for example files	202	most character devices, pipes, fifos and so on, but not for example files
185	or block devices.	203	or block devices.
…		…
210	undef $w;	228	undef $w;
211	});	229	});
212		230
213	=head2 TIME WATCHERS	231	=head2 TIME WATCHERS
214		232
		233	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		234
		235	$w = AnyEvent->timer (
		236	after => <fractional_seconds>,
		237	interval => <fractional_seconds>,
		238	cb => <callback>,
		239	);
		240
215	You can create a time watcher by calling the C<< AnyEvent->timer >>	241	You can create a time watcher by calling the C<< AnyEvent->timer >>
216	method with the following mandatory arguments:	242	method with the following mandatory arguments:
217		243
218	C<after> specifies after how many seconds (fractional values are	244	C<after> specifies after how many seconds (fractional values are
219	supported) the callback should be invoked. C<cb> is the callback to invoke	245	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
340	might affect timers and time-outs.	366	might affect timers and time-outs.
341		367
342	When this is the case, you can call this method, which will update the	368	When this is the case, you can call this method, which will update the
343	event loop's idea of "current time".	369	event loop's idea of "current time".
344		370
		371	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		372	when mod_perl executes the script, then the event loop will have the wrong
		373	idea about the "current time" (being potentially far in the past, when the
		374	script ran the last time). In that case you should arrange a call to C<<
		375	AnyEvent->now_update >> each time the web server process wakes up again
		376	(e.g. at the start of your script, or in a handler).
		377
345	Note that updating the time I<might> cause some events to be handled.	378	Note that updating the time I<might> cause some events to be handled.
346		379
347	=back	380	=back
348		381
349	=head2 SIGNAL WATCHERS	382	=head2 SIGNAL WATCHERS
		383
		384	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
350		385
351	You can watch for signals using a signal watcher, C<signal> is the signal	386	You can watch for signals using a signal watcher, C<signal> is the signal
352	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	387	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
353	callback to be invoked whenever a signal occurs.	388	callback to be invoked whenever a signal occurs.
354		389
…		…
360	invocation, and callback invocation will be synchronous. Synchronous means	395	invocation, and callback invocation will be synchronous. Synchronous means
361	that it might take a while until the signal gets handled by the process,	396	that it might take a while until the signal gets handled by the process,
362	but it is guaranteed not to interrupt any other callbacks.	397	but it is guaranteed not to interrupt any other callbacks.
363		398
364	The main advantage of using these watchers is that you can share a signal	399	The main advantage of using these watchers is that you can share a signal
365	between multiple watchers.	400	between multiple watchers, and AnyEvent will ensure that signals will not
		401	interrupt your program at bad times.
366		402
367	This watcher might use C<%SIG>, so programs overwriting those signals	403	This watcher might use C<%SIG> (depending on the event loop used),
368	directly will likely not work correctly.	404	so programs overwriting those signals directly will likely not work
		405	correctly.
369		406
370	Example: exit on SIGINT	407	Example: exit on SIGINT
371		408
372	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	409	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
373		410
		411	=head3 Restart Behaviour
		412
		413	While restart behaviour is up to the event loop implementation, most will
		414	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		415	pure perl implementation).
		416
		417	=head3 Safe/Unsafe Signals
		418
		419	Perl signals can be either "safe" (synchronous to opcode handling) or
		420	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		421	latter might corrupt your memory.
		422
		423	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		424	i.e. they will not interrupt your running perl program but will only be
		425	called as part of the normal event handling (just like timer, I/O etc.
		426	callbacks, too).
		427
		428	=head3 Signal Races, Delays and Workarounds
		429
		430	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		431	callbacks to signals in a generic way, which is a pity, as you cannot
		432	do race-free signal handling in perl, requiring C libraries for
		433	this. AnyEvent will try to do it's best, which means in some cases,
		434	signals will be delayed. The maximum time a signal might be delayed is
		435	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		436	variable can be changed only before the first signal watcher is created,
		437	and should be left alone otherwise. This variable determines how often
		438	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		439	will cause fewer spurious wake-ups, which is better for power and CPU
		440	saving.
		441
		442	All these problems can be avoided by installing the optional
		443	L<Async::Interrupt> module, which works with most event loops. It will not
		444	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		445	(and not with L<POE> currently, as POE does it's own workaround with
		446	one-second latency). For those, you just have to suffer the delays.
		447
374	=head2 CHILD PROCESS WATCHERS	448	=head2 CHILD PROCESS WATCHERS
375		449
		450	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		451
376	You can also watch on a child process exit and catch its exit status.	452	You can also watch on a child process exit and catch its exit status.
377		453
378	The child process is specified by the C<pid> argument (if set to C<0>, it	454	The child process is specified by the C<pid> argument (one some backends,
379	watches for any child process exit). The watcher will triggered only when	455	using C<0> watches for any child process exit, on others this will
380	the child process has finished and an exit status is available, not on	456	croak). The watcher will be triggered only when the child process has
381	any trace events (stopped/continued).	457	finished and an exit status is available, not on any trace events
		458	(stopped/continued).
382		459
383	The callback will be called with the pid and exit status (as returned by	460	The callback will be called with the pid and exit status (as returned by
384	waitpid), so unlike other watcher types, you I<can> rely on child watcher	461	waitpid), so unlike other watcher types, you I<can> rely on child watcher
385	callback arguments.	462	callback arguments.
386		463
…		…
391		468
392	There is a slight catch to child watchers, however: you usually start them	469	There is a slight catch to child watchers, however: you usually start them
393	I<after> the child process was created, and this means the process could	470	I<after> the child process was created, and this means the process could
394	have exited already (and no SIGCHLD will be sent anymore).	471	have exited already (and no SIGCHLD will be sent anymore).
395		472
396	Not all event models handle this correctly (POE doesn't), but even for	473	Not all event models handle this correctly (neither POE nor IO::Async do,
		474	see their AnyEvent::Impl manpages for details), but even for event models
397	event models that I<do> handle this correctly, they usually need to be	475	that I<do> handle this correctly, they usually need to be loaded before
398	loaded before the process exits (i.e. before you fork in the first place).	476	the process exits (i.e. before you fork in the first place). AnyEvent's
		477	pure perl event loop handles all cases correctly regardless of when you
		478	start the watcher.
399		479
400	This means you cannot create a child watcher as the very first thing in an	480	This means you cannot create a child watcher as the very first
401	AnyEvent program, you I<have> to create at least one watcher before you	481	thing in an AnyEvent program, you I<have> to create at least one
402	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	482	watcher before you C<fork> the child (alternatively, you can call
		483	C<AnyEvent::detect>).
		484
		485	As most event loops do not support waiting for child events, they will be
		486	emulated by AnyEvent in most cases, in which the latency and race problems
		487	mentioned in the description of signal watchers apply.
403		488
404	Example: fork a process and wait for it	489	Example: fork a process and wait for it
405		490
406	my $done = AnyEvent->condvar;	491	my $done = AnyEvent->condvar;
407		492
…		…
419	# do something else, then wait for process exit	504	# do something else, then wait for process exit
420	$done->recv;	505	$done->recv;
421		506
422	=head2 IDLE WATCHERS	507	=head2 IDLE WATCHERS
423		508
424	Sometimes there is a need to do something, but it is not so important	509	$w = AnyEvent->idle (cb => <callback>);
425	to do it instantly, but only when there is nothing better to do. This
426	"nothing better to do" is usually defined to be "no other events need
427	attention by the event loop".
428		510
429	Idle watchers ideally get invoked when the event loop has nothing	511	Repeatedly invoke the callback after the process becomes idle, until
430	better to do, just before it would block the process to wait for new	512	either the watcher is destroyed or new events have been detected.
431	events. Instead of blocking, the idle watcher is invoked.
432		513
433	Most event loops unfortunately do not really support idle watchers (only	514	Idle watchers are useful when there is a need to do something, but it
		515	is not so important (or wise) to do it instantly. The callback will be
		516	invoked only when there is "nothing better to do", which is usually
		517	defined as "all outstanding events have been handled and no new events
		518	have been detected". That means that idle watchers ideally get invoked
		519	when the event loop has just polled for new events but none have been
		520	detected. Instead of blocking to wait for more events, the idle watchers
		521	will be invoked.
		522
		523	Unfortunately, most event loops do not really support idle watchers (only
434	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	524	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
435	will simply call the callback "from time to time".	525	will simply call the callback "from time to time".
436		526
437	Example: read lines from STDIN, but only process them when the	527	Example: read lines from STDIN, but only process them when the
438	program is otherwise idle:	528	program is otherwise idle:
…		…
454	});	544	});
455	});	545	});
456		546
457	=head2 CONDITION VARIABLES	547	=head2 CONDITION VARIABLES
458		548
		549	$cv = AnyEvent->condvar;
		550
		551	$cv->send (<list>);
		552	my @res = $cv->recv;
		553
459	If you are familiar with some event loops you will know that all of them	554	If you are familiar with some event loops you will know that all of them
460	require you to run some blocking "loop", "run" or similar function that	555	require you to run some blocking "loop", "run" or similar function that
461	will actively watch for new events and call your callbacks.	556	will actively watch for new events and call your callbacks.
462		557
463	AnyEvent is different, it expects somebody else to run the event loop and	558	AnyEvent is slightly different: it expects somebody else to run the event
464	will only block when necessary (usually when told by the user).	559	loop and will only block when necessary (usually when told by the user).
465		560
466	The instrument to do that is called a "condition variable", so called	561	The tool to do that is called a "condition variable", so called because
467	because they represent a condition that must become true.	562	they represent a condition that must become true.
		563
		564	Now is probably a good time to look at the examples further below.
468		565
469	Condition variables can be created by calling the C<< AnyEvent->condvar	566	Condition variables can be created by calling the C<< AnyEvent->condvar
470	>> method, usually without arguments. The only argument pair allowed is	567	>> method, usually without arguments. The only argument pair allowed is
471
472	C<cb>, which specifies a callback to be called when the condition variable	568	C<cb>, which specifies a callback to be called when the condition variable
473	becomes true, with the condition variable as the first argument (but not	569	becomes true, with the condition variable as the first argument (but not
474	the results).	570	the results).
475		571
476	After creation, the condition variable is "false" until it becomes "true"	572	After creation, the condition variable is "false" until it becomes "true"
477	by calling the C<send> method (or calling the condition variable as if it	573	by calling the C<send> method (or calling the condition variable as if it
478	were a callback, read about the caveats in the description for the C<<	574	were a callback, read about the caveats in the description for the C<<
479	->send >> method).	575	->send >> method).
480		576
481	Condition variables are similar to callbacks, except that you can	577	Since condition variables are the most complex part of the AnyEvent API, here are
482	optionally wait for them. They can also be called merge points - points	578	some different mental models of what they are - pick the ones you can connect to:
483	in time where multiple outstanding events have been processed. And yet	579
484	another way to call them is transactions - each condition variable can be	580	=over 4
485	used to represent a transaction, which finishes at some point and delivers	581
486	a result.	582	=item * Condition variables are like callbacks - you can call them (and pass them instead
		583	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		584
		585	=item * Condition variables are signals - one side can emit or send them,
		586	the other side can wait for them, or install a handler that is called when
		587	the signal fires.
		588
		589	=item * Condition variables are like "Merge Points" - points in your program
		590	where you merge multiple independent results/control flows into one.
		591
		592	=item * Condition variables represent a transaction - function that start
		593	some kind of transaction can return them, leaving the caller the choice
		594	between waiting in a blocking fashion, or setting a callback.
		595
		596	=item * Condition variables represent future values, or promises to deliver
		597	some result, long before the result is available.
		598
		599	=back
487		600
488	Condition variables are very useful to signal that something has finished,	601	Condition variables are very useful to signal that something has finished,
489	for example, if you write a module that does asynchronous http requests,	602	for example, if you write a module that does asynchronous http requests,
490	then a condition variable would be the ideal candidate to signal the	603	then a condition variable would be the ideal candidate to signal the
491	availability of results. The user can either act when the callback is	604	availability of results. The user can either act when the callback is
…		…
512	eventually calls C<< -> send >>, and the "consumer side", which waits	625	eventually calls C<< -> send >>, and the "consumer side", which waits
513	for the send to occur.	626	for the send to occur.
514		627
515	Example: wait for a timer.	628	Example: wait for a timer.
516		629
517	# wait till the result is ready	630	# condition: "wait till the timer is fired"
518	my $result_ready = AnyEvent->condvar;	631	my $timer_fired = AnyEvent->condvar;
519		632
520	# do something such as adding a timer	633	# create the timer - we could wait for, say
521	# or socket watcher the calls $result_ready->send	634	# a handle becomign ready, or even an
522	# when the "result" is ready.	635	# AnyEvent::HTTP request to finish, but
523	# in this case, we simply use a timer:	636	# in this case, we simply use a timer:
524	my $w = AnyEvent->timer (	637	my $w = AnyEvent->timer (
525	after => 1,	638	after => 1,
526	cb => sub { $result_ready->send },	639	cb => sub { $timer_fired->send },
527	);	640	);
528		641
529	# this "blocks" (while handling events) till the callback	642	# this "blocks" (while handling events) till the callback
530	# calls send	643	# calls ->send
531	$result_ready->recv;	644	$timer_fired->recv;
532		645
533	Example: wait for a timer, but take advantage of the fact that	646	Example: wait for a timer, but take advantage of the fact that condition
534	condition variables are also code references.	647	variables are also callable directly.
535		648
536	my $done = AnyEvent->condvar;	649	my $done = AnyEvent->condvar;
537	my $delay = AnyEvent->timer (after => 5, cb => $done);	650	my $delay = AnyEvent->timer (after => 5, cb => $done);
538	$done->recv;	651	$done->recv;
539		652
…		…
545		658
546	...	659	...
547		660
548	my @info = $couchdb->info->recv;	661	my @info = $couchdb->info->recv;
549		662
550	And this is how you would just ste a callback to be called whenever the	663	And this is how you would just set a callback to be called whenever the
551	results are available:	664	results are available:
552		665
553	$couchdb->info->cb (sub {	666	$couchdb->info->cb (sub {
554	my @info = $_[0]->recv;	667	my @info = $_[0]->recv;
555	});	668	});
…		…
573	immediately from within send.	686	immediately from within send.
574		687
575	Any arguments passed to the C<send> call will be returned by all	688	Any arguments passed to the C<send> call will be returned by all
576	future C<< ->recv >> calls.	689	future C<< ->recv >> calls.
577		690
578	Condition variables are overloaded so one can call them directly	691	Condition variables are overloaded so one can call them directly (as if
579	(as a code reference). Calling them directly is the same as calling	692	they were a code reference). Calling them directly is the same as calling
580	C<send>. Note, however, that many C-based event loops do not handle	693	C<send>.
581	overloading, so as tempting as it may be, passing a condition variable
582	instead of a callback does not work. Both the pure perl and EV loops
583	support overloading, however, as well as all functions that use perl to
584	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
585	example).
586		694
587	=item $cv->croak ($error)	695	=item $cv->croak ($error)
588		696
589	Similar to send, but causes all call's to C<< ->recv >> to invoke	697	Similar to send, but causes all call's to C<< ->recv >> to invoke
590	C<Carp::croak> with the given error message/object/scalar.	698	C<Carp::croak> with the given error message/object/scalar.
591		699
592	This can be used to signal any errors to the condition variable	700	This can be used to signal any errors to the condition variable
593	user/consumer.	701	user/consumer. Doing it this way instead of calling C<croak> directly
		702	delays the error detetcion, but has the overwhelmign advantage that it
		703	diagnoses the error at the place where the result is expected, and not
		704	deep in some event clalback without connection to the actual code causing
		705	the problem.
594		706
595	=item $cv->begin ([group callback])	707	=item $cv->begin ([group callback])
596		708
597	=item $cv->end	709	=item $cv->end
598
599	These two methods are EXPERIMENTAL and MIGHT CHANGE.
600		710
601	These two methods can be used to combine many transactions/events into	711	These two methods can be used to combine many transactions/events into
602	one. For example, a function that pings many hosts in parallel might want	712	one. For example, a function that pings many hosts in parallel might want
603	to use a condition variable for the whole process.	713	to use a condition variable for the whole process.
604		714
605	Every call to C<< ->begin >> will increment a counter, and every call to	715	Every call to C<< ->begin >> will increment a counter, and every call to
606	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	716	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
607	>>, the (last) callback passed to C<begin> will be executed. That callback	717	>>, the (last) callback passed to C<begin> will be executed, passing the
608	is I<supposed> to call C<< ->send >>, but that is not required. If no	718	condvar as first argument. That callback is I<supposed> to call C<< ->send
609	callback was set, C<send> will be called without any arguments.	719	>>, but that is not required. If no group callback was set, C<send> will
		720	be called without any arguments.
610		721
611	Let's clarify this with the ping example:	722	You can think of C<< $cv->send >> giving you an OR condition (one call
		723	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		724	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		725
		726	Let's start with a simple example: you have two I/O watchers (for example,
		727	STDOUT and STDERR for a program), and you want to wait for both streams to
		728	close before activating a condvar:
612		729
613	my $cv = AnyEvent->condvar;	730	my $cv = AnyEvent->condvar;
614		731
		732	$cv->begin; # first watcher
		733	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		734	defined sysread $fh1, my $buf, 4096
		735	or $cv->end;
		736	});
		737
		738	$cv->begin; # second watcher
		739	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		740	defined sysread $fh2, my $buf, 4096
		741	or $cv->end;
		742	});
		743
		744	$cv->recv;
		745
		746	This works because for every event source (EOF on file handle), there is
		747	one call to C<begin>, so the condvar waits for all calls to C<end> before
		748	sending.
		749
		750	The ping example mentioned above is slightly more complicated, as the
		751	there are results to be passwd back, and the number of tasks that are
		752	begung can potentially be zero:
		753
		754	my $cv = AnyEvent->condvar;
		755
615	my %result;	756	my %result;
616	$cv->begin (sub { $cv->send (\%result) });	757	$cv->begin (sub { shift->send (\%result) });
617		758
618	for my $host (@list_of_hosts) {	759	for my $host (@list_of_hosts) {
619	$cv->begin;	760	$cv->begin;
620	ping_host_then_call_callback $host, sub {	761	ping_host_then_call_callback $host, sub {
621	$result{$host} = ...;	762	$result{$host} = ...;
…		…
636	loop, which serves two important purposes: first, it sets the callback	777	loop, which serves two important purposes: first, it sets the callback
637	to be called once the counter reaches C<0>, and second, it ensures that	778	to be called once the counter reaches C<0>, and second, it ensures that
638	C<send> is called even when C<no> hosts are being pinged (the loop	779	C<send> is called even when C<no> hosts are being pinged (the loop
639	doesn't execute once).	780	doesn't execute once).
640		781
641	This is the general pattern when you "fan out" into multiple subrequests:	782	This is the general pattern when you "fan out" into multiple (but
642	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	783	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
643	is called at least once, and then, for each subrequest you start, call	784	the callback and ensure C<end> is called at least once, and then, for each
644	C<begin> and for each subrequest you finish, call C<end>.	785	subrequest you start, call C<begin> and for each subrequest you finish,
		786	call C<end>.
645		787
646	=back	788	=back
647		789
648	=head3 METHODS FOR CONSUMERS	790	=head3 METHODS FOR CONSUMERS
649		791
…		…
665	function will call C<croak>.	807	function will call C<croak>.
666		808
667	In list context, all parameters passed to C<send> will be returned,	809	In list context, all parameters passed to C<send> will be returned,
668	in scalar context only the first one will be returned.	810	in scalar context only the first one will be returned.
669		811
		812	Note that doing a blocking wait in a callback is not supported by any
		813	event loop, that is, recursive invocation of a blocking C<< ->recv
		814	>> is not allowed, and the C<recv> call will C<croak> if such a
		815	condition is detected. This condition can be slightly loosened by using
		816	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		817	any thread that doesn't run the event loop itself.
		818
670	Not all event models support a blocking wait - some die in that case	819	Not all event models support a blocking wait - some die in that case
671	(programs might want to do that to stay interactive), so I<if you are	820	(programs might want to do that to stay interactive), so I<if you are
672	using this from a module, never require a blocking wait>, but let the	821	using this from a module, never require a blocking wait>. Instead, let the
673	caller decide whether the call will block or not (for example, by coupling	822	caller decide whether the call will block or not (for example, by coupling
674	condition variables with some kind of request results and supporting	823	condition variables with some kind of request results and supporting
675	callbacks so the caller knows that getting the result will not block,	824	callbacks so the caller knows that getting the result will not block,
676	while still supporting blocking waits if the caller so desires).	825	while still supporting blocking waits if the caller so desires).
677		826
678	Another reason I<never> to C<< ->recv >> in a module is that you cannot
679	sensibly have two C<< ->recv >>'s in parallel, as that would require
680	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
681	can supply.
682
683	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
684	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
685	versions and also integrates coroutines into AnyEvent, making blocking
686	C<< ->recv >> calls perfectly safe as long as they are done from another
687	coroutine (one that doesn't run the event loop).
688
689	You can ensure that C<< -recv >> never blocks by setting a callback and	827	You can ensure that C<< -recv >> never blocks by setting a callback and
690	only calling C<< ->recv >> from within that callback (or at a later	828	only calling C<< ->recv >> from within that callback (or at a later
691	time). This will work even when the event loop does not support blocking	829	time). This will work even when the event loop does not support blocking
692	waits otherwise.	830	waits otherwise.
693		831
…		…
699	=item $cb = $cv->cb ($cb->($cv))	837	=item $cb = $cv->cb ($cb->($cv))
700		838
701	This is a mutator function that returns the callback set and optionally	839	This is a mutator function that returns the callback set and optionally
702	replaces it before doing so.	840	replaces it before doing so.
703		841
704	The callback will be called when the condition becomes "true", i.e. when	842	The callback will be called when the condition becomes (or already was)
705	C<send> or C<croak> are called, with the only argument being the condition	843	"true", i.e. when C<send> or C<croak> are called (or were called), with
706	variable itself. Calling C<recv> inside the callback or at any later time	844	the only argument being the condition variable itself. Calling C<recv>
707	is guaranteed not to block.	845	inside the callback or at any later time is guaranteed not to block.
708		846
709	=back	847	=back
710		848
		849	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		850
		851	The available backend classes are (every class has its own manpage):
		852
		853	=over 4
		854
		855	=item Backends that are autoprobed when no other event loop can be found.
		856
		857	EV is the preferred backend when no other event loop seems to be in
		858	use. If EV is not installed, then AnyEvent will fall back to its own
		859	pure-perl implementation, which is available everywhere as it comes with
		860	AnyEvent itself.
		861
		862	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		863	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		864
		865	=item Backends that are transparently being picked up when they are used.
		866
		867	These will be used when they are currently loaded when the first watcher
		868	is created, in which case it is assumed that the application is using
		869	them. This means that AnyEvent will automatically pick the right backend
		870	when the main program loads an event module before anything starts to
		871	create watchers. Nothing special needs to be done by the main program.
		872
		873	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		874	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		875	AnyEvent::Impl::Tk based on Tk, very broken.
		876	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		877	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		878	AnyEvent::Impl::Irssi used when running within irssi.
		879
		880	=item Backends with special needs.
		881
		882	Qt requires the Qt::Application to be instantiated first, but will
		883	otherwise be picked up automatically. As long as the main program
		884	instantiates the application before any AnyEvent watchers are created,
		885	everything should just work.
		886
		887	AnyEvent::Impl::Qt based on Qt.
		888
		889	Support for IO::Async can only be partial, as it is too broken and
		890	architecturally limited to even support the AnyEvent API. It also
		891	is the only event loop that needs the loop to be set explicitly, so
		892	it can only be used by a main program knowing about AnyEvent. See
		893	L<AnyEvent::Impl::Async> for the gory details.
		894
		895	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		896
		897	=item Event loops that are indirectly supported via other backends.
		898
		899	Some event loops can be supported via other modules:
		900
		901	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		902
		903	B<WxWidgets> has no support for watching file handles. However, you can
		904	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		905	polls 20 times per second, which was considered to be too horrible to even
		906	consider for AnyEvent.
		907
		908	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		909	backend, so it can be supported through POE.
		910
		911	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		912	load L<POE> when detecting them, in the hope that POE will pick them up,
		913	in which case everything will be automatic.
		914
		915	=back
		916
711	=head1 GLOBAL VARIABLES AND FUNCTIONS	917	=head1 GLOBAL VARIABLES AND FUNCTIONS
712		918
		919	These are not normally required to use AnyEvent, but can be useful to
		920	write AnyEvent extension modules.
		921
713	=over 4	922	=over 4
714		923
715	=item $AnyEvent::MODEL	924	=item $AnyEvent::MODEL
716		925
717	Contains C<undef> until the first watcher is being created. Then it	926	Contains C<undef> until the first watcher is being created, before the
		927	backend has been autodetected.
		928
718	contains the event model that is being used, which is the name of the	929	Afterwards it contains the event model that is being used, which is the
719	Perl class implementing the model. This class is usually one of the	930	name of the Perl class implementing the model. This class is usually one
720	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	931	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
721	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	932	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
722		933	will be C<urxvt::anyevent>).
723	The known classes so far are:
724
725	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
726	AnyEvent::Impl::Event based on Event, second best choice.
727	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
728	AnyEvent::Impl::Glib based on Glib, third-best choice.
729	AnyEvent::Impl::Tk based on Tk, very bad choice.
730	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
731	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
732	AnyEvent::Impl::POE based on POE, not generic enough for full support.
733
734	There is no support for WxWidgets, as WxWidgets has no support for
735	watching file handles. However, you can use WxWidgets through the
736	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
737	second, which was considered to be too horrible to even consider for
738	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
739	it's adaptor.
740
741	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
742	autodetecting them.
743		934
744	=item AnyEvent::detect	935	=item AnyEvent::detect
745		936
746	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	937	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
747	if necessary. You should only call this function right before you would	938	if necessary. You should only call this function right before you would
748	have created an AnyEvent watcher anyway, that is, as late as possible at	939	have created an AnyEvent watcher anyway, that is, as late as possible at
749	runtime.	940	runtime, and not e.g. while initialising of your module.
		941
		942	If you need to do some initialisation before AnyEvent watchers are
		943	created, use C<post_detect>.
750		944
751	=item $guard = AnyEvent::post_detect { BLOCK }	945	=item $guard = AnyEvent::post_detect { BLOCK }
752		946
753	Arranges for the code block to be executed as soon as the event model is	947	Arranges for the code block to be executed as soon as the event model is
754	autodetected (or immediately if this has already happened).	948	autodetected (or immediately if this has already happened).
755		949
		950	The block will be executed I<after> the actual backend has been detected
		951	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		952	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		953	other initialisations - see the sources of L<AnyEvent::Strict> or
		954	L<AnyEvent::AIO> to see how this is used.
		955
		956	The most common usage is to create some global watchers, without forcing
		957	event module detection too early, for example, L<AnyEvent::AIO> creates
		958	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		959	avoid autodetecting the event module at load time.
		960
756	If called in scalar or list context, then it creates and returns an object	961	If called in scalar or list context, then it creates and returns an object
757	that automatically removes the callback again when it is destroyed. See	962	that automatically removes the callback again when it is destroyed (or
		963	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
758	L<Coro::BDB> for a case where this is useful.	964	a case where this is useful.
		965
		966	Example: Create a watcher for the IO::AIO module and store it in
		967	C<$WATCHER>. Only do so after the event loop is initialised, though.
		968
		969	our WATCHER;
		970
		971	my $guard = AnyEvent::post_detect {
		972	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		973	};
		974
		975	# the ||= is important in case post_detect immediately runs the block,
		976	# as to not clobber the newly-created watcher. assigning both watcher and
		977	# post_detect guard to the same variable has the advantage of users being
		978	# able to just C<undef $WATCHER> if the watcher causes them grief.
		979
		980	$WATCHER ||= $guard;
759		981
760	=item @AnyEvent::post_detect	982	=item @AnyEvent::post_detect
761		983
762	If there are any code references in this array (you can C<push> to it	984	If there are any code references in this array (you can C<push> to it
763	before or after loading AnyEvent), then they will called directly after	985	before or after loading AnyEvent), then they will called directly after
764	the event loop has been chosen.	986	the event loop has been chosen.
765		987
766	You should check C<$AnyEvent::MODEL> before adding to this array, though:	988	You should check C<$AnyEvent::MODEL> before adding to this array, though:
767	if it contains a true value then the event loop has already been detected,	989	if it is defined then the event loop has already been detected, and the
768	and the array will be ignored.	990	array will be ignored.
769		991
770	Best use C<AnyEvent::post_detect { BLOCK }> instead.	992	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		993	it, as it takes care of these details.
		994
		995	This variable is mainly useful for modules that can do something useful
		996	when AnyEvent is used and thus want to know when it is initialised, but do
		997	not need to even load it by default. This array provides the means to hook
		998	into AnyEvent passively, without loading it.
		999
		1000	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1001	together, you could put this into Coro (this is the actual code used by
		1002	Coro to accomplish this):
		1003
		1004	if (defined $AnyEvent::MODEL) {
		1005	# AnyEvent already initialised, so load Coro::AnyEvent
		1006	require Coro::AnyEvent;
		1007	} else {
		1008	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1009	# as soon as it is
		1010	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1011	}
771		1012
772	=back	1013	=back
773		1014
774	=head1 WHAT TO DO IN A MODULE	1015	=head1 WHAT TO DO IN A MODULE
775		1016
…		…
830		1071
831		1072
832	=head1 OTHER MODULES	1073	=head1 OTHER MODULES
833		1074
834	The following is a non-exhaustive list of additional modules that use	1075	The following is a non-exhaustive list of additional modules that use
835	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1076	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
836	in the same program. Some of the modules come with AnyEvent, some are	1077	modules and other event loops in the same program. Some of the modules
837	available via CPAN.	1078	come as part of AnyEvent, the others are available via CPAN.
838		1079
839	=over 4	1080	=over 4
840		1081
841	=item L<AnyEvent::Util>	1082	=item L<AnyEvent::Util>
842		1083
…		…
851		1092
852	=item L<AnyEvent::Handle>	1093	=item L<AnyEvent::Handle>
853		1094
854	Provide read and write buffers, manages watchers for reads and writes,	1095	Provide read and write buffers, manages watchers for reads and writes,
855	supports raw and formatted I/O, I/O queued and fully transparent and	1096	supports raw and formatted I/O, I/O queued and fully transparent and
856	non-blocking SSL/TLS.	1097	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
857		1098
858	=item L<AnyEvent::DNS>	1099	=item L<AnyEvent::DNS>
859		1100
860	Provides rich asynchronous DNS resolver capabilities.	1101	Provides rich asynchronous DNS resolver capabilities.
861		1102
		1103	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1104
		1105	Implement event-based interfaces to the protocols of the same name (for
		1106	the curious, IGS is the International Go Server and FCP is the Freenet
		1107	Client Protocol).
		1108
		1109	=item L<AnyEvent::Handle::UDP>
		1110
		1111	Here be danger!
		1112
		1113	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1114	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1115	it's use of a stream-based API with a protocol that isn't streamable, that
		1116	the only way to improve it is to delete it.
		1117
		1118	It features data corruption (but typically only under load) and general
		1119	confusion. On top, the author is not only clueless about UDP but also
		1120	fact-resistant - some gems of his understanding: "connect doesn't work
		1121	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1122	packets", "I don't need to implement proper error checking as UDP doesn't
		1123	support error checking" and so on - he doesn't even understand what's
		1124	wrong with his module when it is explained to him.
		1125
862	=item L<AnyEvent::HTTP>	1126	=item L<AnyEvent::DBI>
863		1127
864	A simple-to-use HTTP library that is capable of making a lot of concurrent	1128	Executes L<DBI> requests asynchronously in a proxy process for you,
865	HTTP requests.	1129	notifying you in an event-bnased way when the operation is finished.
		1130
		1131	=item L<AnyEvent::AIO>
		1132
		1133	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1134	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1135	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1136	file I/O, and much more.
866		1137
867	=item L<AnyEvent::HTTPD>	1138	=item L<AnyEvent::HTTPD>
868		1139
869	Provides a simple web application server framework.	1140	A simple embedded webserver.
870		1141
871	=item L<AnyEvent::FastPing>	1142	=item L<AnyEvent::FastPing>
872		1143
873	The fastest ping in the west.	1144	The fastest ping in the west.
874		1145
875	=item L<AnyEvent::DBI>
876
877	Executes L<DBI> requests asynchronously in a proxy process.
878
879	=item L<AnyEvent::AIO>
880
881	Truly asynchronous I/O, should be in the toolbox of every event
882	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
883	together.
884
885	=item L<AnyEvent::BDB>
886
887	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
888	L<BDB> and AnyEvent together.
889
890	=item L<AnyEvent::GPSD>
891
892	A non-blocking interface to gpsd, a daemon delivering GPS information.
893
894	=item L<AnyEvent::IGS>
895
896	A non-blocking interface to the Internet Go Server protocol (used by
897	L<App::IGS>).
898
899	=item L<AnyEvent::IRC>
900
901	AnyEvent based IRC client module family (replacing the older Net::IRC3).
902
903	=item L<Net::XMPP2>
904
905	AnyEvent based XMPP (Jabber protocol) module family.
906
907	=item L<Net::FCP>
908
909	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
910	of AnyEvent.
911
912	=item L<Event::ExecFlow>
913
914	High level API for event-based execution flow control.
915
916	=item L<Coro>	1146	=item L<Coro>
917		1147
918	Has special support for AnyEvent via L<Coro::AnyEvent>.	1148	Has special support for AnyEvent via L<Coro::AnyEvent>.
919		1149
920	=item L<IO::Lambda>
921
922	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
923
924	=back	1150	=back
925		1151
926	=cut	1152	=cut
927		1153
928	package AnyEvent;	1154	package AnyEvent;
929		1155
930	no warnings;	1156	# basically a tuned-down version of common::sense
931	use strict qw(vars subs);	1157	sub common_sense {
		1158	# from common:.sense 1.0
		1159	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
		1160	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1161	$^H |= 0x00000600;
		1162	}
932		1163
		1164	BEGIN { AnyEvent::common_sense }
		1165
933	use Carp;	1166	use Carp ();
934		1167
935	our $VERSION = 4.4;	1168	our $VERSION = '5.261';
936	our $MODEL;	1169	our $MODEL;
937		1170
938	our $AUTOLOAD;	1171	our $AUTOLOAD;
939	our @ISA;	1172	our @ISA;
940		1173
941	our @REGISTRY;	1174	our @REGISTRY;
942		1175
943	our $WIN32;	1176	our $VERBOSE;
944		1177
945	BEGIN {	1178	BEGIN {
946	my $win32 = ! ! ($^O =~ /mswin32/i);	1179	require "AnyEvent/constants.pl";
947	eval "sub WIN32(){ $win32 }";
948	}
949		1180
		1181	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
		1182
		1183	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1184	if ${^TAINT};
		1185
950	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1186	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1187
		1188	}
		1189
		1190	our $MAX_SIGNAL_LATENCY = 10;
951		1191
952	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1192	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
953		1193
954	{	1194	{
955	my $idx;	1195	my $idx;
…		…
957	for reverse split /\s*,\s*/,	1197	for reverse split /\s*,\s*/,
958	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1198	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
959	}	1199	}
960		1200
961	my @models = (	1201	my @models = (
962	[EV:: => AnyEvent::Impl::EV::],	1202	[EV:: => AnyEvent::Impl::EV:: , 1],
963	[Event:: => AnyEvent::Impl::Event::],
964	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1203	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
965	# everything below here will not be autoprobed	1204	# everything below here will not (normally) be autoprobed
966	# as the pureperl backend should work everywhere	1205	# as the pureperl backend should work everywhere
967	# and is usually faster	1206	# and is usually faster
		1207	[Event:: => AnyEvent::Impl::Event::, 1],
		1208	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1209	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1210	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
968	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1211	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
969	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
970	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
971	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1212	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
972	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1213	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
973	[Wx:: => AnyEvent::Impl::POE::],	1214	[Wx:: => AnyEvent::Impl::POE::],
974	[Prima:: => AnyEvent::Impl::POE::],	1215	[Prima:: => AnyEvent::Impl::POE::],
		1216	# IO::Async is just too broken - we would need workarounds for its
		1217	# byzantine signal and broken child handling, among others.
		1218	# IO::Async is rather hard to detect, as it doesn't have any
		1219	# obvious default class.
		1220	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1221	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1222	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1223	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
975	);	1224	);
976		1225
977	our %method = map +($_ => 1),	1226	our %method = map +($_ => 1),
978	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1227	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
979		1228
980	our @post_detect;	1229	our @post_detect;
981		1230
982	sub post_detect(&) {	1231	sub post_detect(&) {
983	my ($cb) = @_;	1232	my ($cb) = @_;
984		1233
985	if ($MODEL) {
986	$cb->();
987
988	1
989	} else {
990	push @post_detect, $cb;	1234	push @post_detect, $cb;
991		1235
992	defined wantarray	1236	defined wantarray
993	? bless \$cb, "AnyEvent::Util::postdetect"	1237	? bless \$cb, "AnyEvent::Util::postdetect"
994	: ()	1238	: ()
995	}
996	}	1239	}
997		1240
998	sub AnyEvent::Util::postdetect::DESTROY {	1241	sub AnyEvent::Util::postdetect::DESTROY {
999	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1242	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1000	}	1243	}
1001		1244
1002	sub detect() {	1245	sub detect() {
		1246	# free some memory
		1247	*detect = sub () { $MODEL };
		1248
		1249	local $!; # for good measure
		1250	local $SIG{__DIE__};
		1251
		1252	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1253	my $model = "AnyEvent::Impl::$1";
		1254	if (eval "require $model") {
		1255	$MODEL = $model;
		1256	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1257	} else {
		1258	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1259	}
		1260	}
		1261
		1262	# check for already loaded models
1003	unless ($MODEL) {	1263	unless ($MODEL) {
1004	no strict 'refs';	1264	for (@REGISTRY, @models) {
1005	local $SIG{__DIE__};	1265	my ($package, $model) = @$_;
1006		1266	if (${"$package\::VERSION"} > 0) {
1007	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1008	my $model = "AnyEvent::Impl::$1";
1009	if (eval "require $model") {	1267	if (eval "require $model") {
1010	$MODEL = $model;	1268	$MODEL = $model;
1011	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1269	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1012	} else {	1270	last;
1013	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1271	}
1014	}	1272	}
1015	}	1273	}
1016		1274
1017	# check for already loaded models
1018	unless ($MODEL) {	1275	unless ($MODEL) {
		1276	# try to autoload a model
1019	for (@REGISTRY, @models) {	1277	for (@REGISTRY, @models) {
1020	my ($package, $model) = @$_;	1278	my ($package, $model, $autoload) = @$_;
		1279	if (
		1280	$autoload
		1281	and eval "require $package"
1021	if (${"$package\::VERSION"} > 0) {	1282	and ${"$package\::VERSION"} > 0
1022	if (eval "require $model") {	1283	and eval "require $model"
		1284	) {
1023	$MODEL = $model;	1285	$MODEL = $model;
1024	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1286	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1025	last;	1287	last;
1026	}
1027	}	1288	}
1028	}	1289	}
1029		1290
1030	unless ($MODEL) {
1031	# try to load a model
1032
1033	for (@REGISTRY, @models) {
1034	my ($package, $model) = @$_;
1035	if (eval "require $package"
1036	and ${"$package\::VERSION"} > 0
1037	and eval "require $model") {
1038	$MODEL = $model;
1039	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1040	last;
1041	}
1042	}
1043
1044	$MODEL	1291	$MODEL
1045	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1292	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
1046	}
1047	}	1293	}
1048
1049	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1050
1051	unshift @ISA, $MODEL;
1052
1053	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1054
1055	(shift @post_detect)->() while @post_detect;
1056	}	1294	}
		1295
		1296	@models = (); # free probe data
		1297
		1298	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1299	unshift @ISA, $MODEL;
		1300
		1301	# now nuke some methods that are overriden by the backend.
		1302	# SUPER is not allowed.
		1303	for (qw(time signal child idle)) {
		1304	undef &{"AnyEvent::Base::$_"}
		1305	if defined &{"$MODEL\::$_"};
		1306	}
		1307
		1308	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1309
		1310	(shift @post_detect)->() while @post_detect;
		1311
		1312	*post_detect = sub(&) {
		1313	shift->();
		1314
		1315	undef
		1316	};
1057		1317
1058	$MODEL	1318	$MODEL
1059	}	1319	}
1060		1320
1061	sub AUTOLOAD {	1321	sub AUTOLOAD {
1062	(my $func = $AUTOLOAD) =~ s/.*://;	1322	(my $func = $AUTOLOAD) =~ s/.*://;
1063		1323
1064	$method{$func}	1324	$method{$func}
1065	or croak "$func: not a valid method for AnyEvent objects";	1325	or Carp::croak "$func: not a valid AnyEvent class method";
1066		1326
1067	detect unless $MODEL;	1327	detect;
1068		1328
1069	my $class = shift;	1329	my $class = shift;
1070	$class->$func (@_);	1330	$class->$func (@_);
1071	}	1331	}
1072		1332
1073	# utility function to dup a filehandle. this is used by many backends	1333	# utility function to dup a filehandle. this is used by many backends
1074	# to support binding more than one watcher per filehandle (they usually	1334	# to support binding more than one watcher per filehandle (they usually
1075	# allow only one watcher per fd, so we dup it to get a different one).	1335	# allow only one watcher per fd, so we dup it to get a different one).
1076	sub _dupfh($$$$) {	1336	sub _dupfh($$;$$) {
1077	my ($poll, $fh, $r, $w) = @_;	1337	my ($poll, $fh, $r, $w) = @_;
1078		1338
1079	# cygwin requires the fh mode to be matching, unix doesn't	1339	# cygwin requires the fh mode to be matching, unix doesn't
1080	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1340	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1081	: $poll eq "w" ? ($w, ">")
1082	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1083		1341
1084	open my $fh2, "$mode&" . fileno $fh	1342	open my $fh2, $mode, $fh
1085	or die "cannot dup() filehandle: $!,";	1343	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1086		1344
1087	# we assume CLOEXEC is already set by perl in all important cases	1345	# we assume CLOEXEC is already set by perl in all important cases
1088		1346
1089	($fh2, $rw)	1347	($fh2, $rw)
1090	}	1348	}
1091		1349
		1350	=head1 SIMPLIFIED AE API
		1351
		1352	Starting with version 5.0, AnyEvent officially supports a second, much
		1353	simpler, API that is designed to reduce the calling, typing and memory
		1354	overhead by using function call syntax and a fixed number of parameters.
		1355
		1356	See the L<AE> manpage for details.
		1357
		1358	=cut
		1359
		1360	package AE;
		1361
		1362	our $VERSION = $AnyEvent::VERSION;
		1363
		1364	# fall back to the main API by default - backends and AnyEvent::Base
		1365	# implementations can overwrite these.
		1366
		1367	sub io($$$) {
		1368	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1369	}
		1370
		1371	sub timer($$$) {
		1372	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1373	}
		1374
		1375	sub signal($$) {
		1376	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1377	}
		1378
		1379	sub child($$) {
		1380	AnyEvent->child (pid => $_[0], cb => $_[1])
		1381	}
		1382
		1383	sub idle($) {
		1384	AnyEvent->idle (cb => $_[0])
		1385	}
		1386
		1387	sub cv(;&) {
		1388	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1389	}
		1390
		1391	sub now() {
		1392	AnyEvent->now
		1393	}
		1394
		1395	sub now_update() {
		1396	AnyEvent->now_update
		1397	}
		1398
		1399	sub time() {
		1400	AnyEvent->time
		1401	}
		1402
1092	package AnyEvent::Base;	1403	package AnyEvent::Base;
1093		1404
1094	# default implementations for many methods	1405	# default implementations for many methods
1095		1406
1096	BEGIN {	1407	sub time {
		1408	eval q{ # poor man's autoloading {}
		1409	# probe for availability of Time::HiRes
1097	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1410	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1411	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1098	*_time = \&Time::HiRes::time;	1412	*AE::time = \&Time::HiRes::time;
1099	# if (eval "use POSIX (); (POSIX::times())...	1413	# if (eval "use POSIX (); (POSIX::times())...
1100	} else {	1414	} else {
		1415	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1101	*_time = sub { time }; # epic fail	1416	*AE::time = sub (){ time }; # epic fail
		1417	}
		1418
		1419	*time = sub { AE::time }; # different prototypes
		1420	};
		1421	die if $@;
		1422
		1423	&time
		1424	}
		1425
		1426	*now = \&time;
		1427
		1428	sub now_update { }
		1429
		1430	# default implementation for ->condvar
		1431
		1432	sub condvar {
		1433	eval q{ # poor man's autoloading {}
		1434	*condvar = sub {
		1435	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1436	};
		1437
		1438	*AE::cv = sub (;&) {
		1439	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1440	};
		1441	};
		1442	die if $@;
		1443
		1444	&condvar
		1445	}
		1446
		1447	# default implementation for ->signal
		1448
		1449	our $HAVE_ASYNC_INTERRUPT;
		1450
		1451	sub _have_async_interrupt() {
		1452	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1453	&& eval "use Async::Interrupt 1.02 (); 1")
		1454	unless defined $HAVE_ASYNC_INTERRUPT;
		1455
		1456	$HAVE_ASYNC_INTERRUPT
		1457	}
		1458
		1459	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1460	our (%SIG_ASY, %SIG_ASY_W);
		1461	our ($SIG_COUNT, $SIG_TW);
		1462
		1463	# install a dummy wakeup watcher to reduce signal catching latency
		1464	# used by Impls
		1465	sub _sig_add() {
		1466	unless ($SIG_COUNT++) {
		1467	# try to align timer on a full-second boundary, if possible
		1468	my $NOW = AE::now;
		1469
		1470	$SIG_TW = AE::timer
		1471	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1472	$MAX_SIGNAL_LATENCY,
		1473	sub { } # just for the PERL_ASYNC_CHECK
		1474	;
1102	}	1475	}
1103	}	1476	}
1104		1477
1105	sub time { _time }	1478	sub _sig_del {
1106	sub now { _time }	1479	undef $SIG_TW
1107	sub now_update { }	1480	unless --$SIG_COUNT;
1108
1109	# default implementation for ->condvar
1110
1111	sub condvar {
1112	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1113	}	1481	}
1114		1482
1115	# default implementation for ->signal	1483	our $_sig_name_init; $_sig_name_init = sub {
		1484	eval q{ # poor man's autoloading {}
		1485	undef $_sig_name_init;
1116		1486
1117	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1487	if (_have_async_interrupt) {
		1488	*sig2num = \&Async::Interrupt::sig2num;
		1489	*sig2name = \&Async::Interrupt::sig2name;
		1490	} else {
		1491	require Config;
1118		1492
1119	sub _signal_exec {	1493	my %signame2num;
1120	sysread $SIGPIPE_R, my $dummy, 4;	1494	@signame2num{ split ' ', $Config::Config{sig_name} }
		1495	= split ' ', $Config::Config{sig_num};
1121		1496
1122	while (%SIG_EV) {	1497	my @signum2name;
1123	for (keys %SIG_EV) {	1498	@signum2name[values %signame2num] = keys %signame2num;
1124	delete $SIG_EV{$_};	1499
1125	$_->() for values %{ $SIG_CB{$_} || {} };	1500	*sig2num = sub($) {
		1501	$_[0] > 0 ? shift : $signame2num{+shift}
		1502	};
		1503	*sig2name = sub ($) {
		1504	$_[0] > 0 ? $signum2name[+shift] : shift
		1505	};
1126	}	1506	}
1127	}	1507	};
1128	}	1508	die if $@;
		1509	};
		1510
		1511	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1512	sub sig2name($) { &$_sig_name_init; &sig2name }
1129		1513
1130	sub signal {	1514	sub signal {
1131	my (undef, %arg) = @_;	1515	eval q{ # poor man's autoloading {}
		1516	# probe for availability of Async::Interrupt
		1517	if (_have_async_interrupt) {
		1518	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1132		1519
1133	unless ($SIGPIPE_R) {	1520	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1134	require Fcntl;	1521	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1135		1522
1136	if (AnyEvent::WIN32) {
1137	require AnyEvent::Util;
1138
1139	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1140	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1141	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1142	} else {	1523	} else {
		1524	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1525
		1526	if (AnyEvent::WIN32) {
		1527	require AnyEvent::Util;
		1528
		1529	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1530	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1531	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1532	} else {
1143	pipe $SIGPIPE_R, $SIGPIPE_W;	1533	pipe $SIGPIPE_R, $SIGPIPE_W;
1144	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1534	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1145	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1535	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1536
		1537	# not strictly required, as $^F is normally 2, but let's make sure...
		1538	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1539	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1540	}
		1541
		1542	$SIGPIPE_R
		1543	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1544
		1545	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1146	}	1546	}
1147		1547
1148	$SIGPIPE_R	1548	*signal = $HAVE_ASYNC_INTERRUPT
1149	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1549	? sub {
		1550	my (undef, %arg) = @_;
1150		1551
1151	# not strictly required, as $^F is normally 2, but let's make sure...	1552	# async::interrupt
1152	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1153	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1154
1155	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1156	}
1157
1158	my $signal = uc $arg{signal}	1553	my $signal = sig2num $arg{signal};
1159	or Carp::croak "required option 'signal' is missing";
1160
1161	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1554	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1555
		1556	$SIG_ASY{$signal} ||= new Async::Interrupt
		1557	cb => sub { undef $SIG_EV{$signal} },
		1558	signal => $signal,
		1559	pipe => [$SIGPIPE_R->filenos],
		1560	pipe_autodrain => 0,
		1561	;
		1562
		1563	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1564	}
		1565	: sub {
		1566	my (undef, %arg) = @_;
		1567
		1568	# pure perl
		1569	my $signal = sig2name $arg{signal};
		1570	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1571
1162	$SIG{$signal} ||= sub {	1572	$SIG{$signal} ||= sub {
1163	local $!;	1573	local $!;
1164	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1574	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1165	undef $SIG_EV{$signal};	1575	undef $SIG_EV{$signal};
		1576	};
		1577
		1578	# can't do signal processing without introducing races in pure perl,
		1579	# so limit the signal latency.
		1580	_sig_add;
		1581
		1582	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1583	}
		1584	;
		1585
		1586	*AnyEvent::Base::signal::DESTROY = sub {
		1587	my ($signal, $cb) = @{$_[0]};
		1588
		1589	_sig_del;
		1590
		1591	delete $SIG_CB{$signal}{$cb};
		1592
		1593	$HAVE_ASYNC_INTERRUPT
		1594	? delete $SIG_ASY{$signal}
		1595	: # delete doesn't work with older perls - they then
		1596	# print weird messages, or just unconditionally exit
		1597	# instead of getting the default action.
		1598	undef $SIG{$signal}
		1599	unless keys %{ $SIG_CB{$signal} };
		1600	};
		1601
		1602	*_signal_exec = sub {
		1603	$HAVE_ASYNC_INTERRUPT
		1604	? $SIGPIPE_R->drain
		1605	: sysread $SIGPIPE_R, (my $dummy), 9;
		1606
		1607	while (%SIG_EV) {
		1608	for (keys %SIG_EV) {
		1609	delete $SIG_EV{$_};
		1610	$_->() for values %{ $SIG_CB{$_} || {} };
		1611	}
		1612	}
		1613	};
1166	};	1614	};
		1615	die if $@;
1167		1616
1168	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1617	&signal
1169	}
1170
1171	sub AnyEvent::Base::signal::DESTROY {
1172	my ($signal, $cb) = @{$_[0]};
1173
1174	delete $SIG_CB{$signal}{$cb};
1175
1176	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1177	}	1618	}
1178		1619
1179	# default implementation for ->child	1620	# default implementation for ->child
1180		1621
1181	our %PID_CB;	1622	our %PID_CB;
1182	our $CHLD_W;	1623	our $CHLD_W;
1183	our $CHLD_DELAY_W;	1624	our $CHLD_DELAY_W;
1184	our $PID_IDLE;
1185	our $WNOHANG;	1625	our $WNOHANG;
1186		1626
1187	sub _child_wait {	1627	# used by many Impl's
1188	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1628	sub _emit_childstatus($$) {
		1629	my (undef, $rpid, $rstatus) = @_;
		1630
		1631	$_->($rpid, $rstatus)
1189	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1632	for values %{ $PID_CB{$rpid} || {} },
1190	(values %{ $PID_CB{0} || {} });	1633	values %{ $PID_CB{0} || {} };
1191	}
1192
1193	undef $PID_IDLE;
1194	}
1195
1196	sub _sigchld {
1197	# make sure we deliver these changes "synchronous" with the event loop.
1198	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
1199	undef $CHLD_DELAY_W;
1200	&_child_wait;
1201	});
1202	}	1634	}
1203		1635
1204	sub child {	1636	sub child {
		1637	eval q{ # poor man's autoloading {}
		1638	*_sigchld = sub {
		1639	my $pid;
		1640
		1641	AnyEvent->_emit_childstatus ($pid, $?)
		1642	while ($pid = waitpid -1, $WNOHANG) > 0;
		1643	};
		1644
		1645	*child = sub {
1205	my (undef, %arg) = @_;	1646	my (undef, %arg) = @_;
1206		1647
1207	defined (my $pid = $arg{pid} + 0)	1648	defined (my $pid = $arg{pid} + 0)
1208	or Carp::croak "required option 'pid' is missing";	1649	or Carp::croak "required option 'pid' is missing";
1209		1650
1210	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1651	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1211		1652
1212	unless ($WNOHANG) {	1653	# WNOHANG is almost cetrainly 1 everywhere
		1654	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1655	? 1
1213	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1656	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1214	}
1215		1657
1216	unless ($CHLD_W) {	1658	unless ($CHLD_W) {
1217	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1659	$CHLD_W = AE::signal CHLD => \&_sigchld;
1218	# child could be a zombie already, so make at least one round	1660	# child could be a zombie already, so make at least one round
1219	&_sigchld;	1661	&_sigchld;
1220	}	1662	}
1221		1663
1222	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1664	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1223	}	1665	};
1224		1666
1225	sub AnyEvent::Base::child::DESTROY {	1667	*AnyEvent::Base::child::DESTROY = sub {
1226	my ($pid, $cb) = @{$_[0]};	1668	my ($pid, $cb) = @{$_[0]};
1227		1669
1228	delete $PID_CB{$pid}{$cb};	1670	delete $PID_CB{$pid}{$cb};
1229	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1671	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1230		1672
1231	undef $CHLD_W unless keys %PID_CB;	1673	undef $CHLD_W unless keys %PID_CB;
		1674	};
		1675	};
		1676	die if $@;
		1677
		1678	&child
1232	}	1679	}
1233		1680
1234	# idle emulation is done by simply using a timer, regardless	1681	# idle emulation is done by simply using a timer, regardless
1235	# of whether the proces sis idle or not, and not letting	1682	# of whether the process is idle or not, and not letting
1236	# the callback use more than 50% of the time.	1683	# the callback use more than 50% of the time.
1237	sub idle {	1684	sub idle {
		1685	eval q{ # poor man's autoloading {}
		1686	*idle = sub {
1238	my (undef, %arg) = @_;	1687	my (undef, %arg) = @_;
1239		1688
1240	my ($cb, $w, $rcb) = $arg{cb};	1689	my ($cb, $w, $rcb) = $arg{cb};
1241		1690
1242	$rcb = sub {	1691	$rcb = sub {
1243	if ($cb) {	1692	if ($cb) {
1244	$w = _time;	1693	$w = _time;
1245	&$cb;	1694	&$cb;
1246	$w = _time - $w;	1695	$w = _time - $w;
1247		1696
1248	# never use more then 50% of the time for the idle watcher,	1697	# never use more then 50% of the time for the idle watcher,
1249	# within some limits	1698	# within some limits
1250	$w = 0.0001 if $w < 0.0001;	1699	$w = 0.0001 if $w < 0.0001;
1251	$w = 5 if $w > 5;	1700	$w = 5 if $w > 5;
1252		1701
1253	$w = AnyEvent->timer (after => $w, cb => $rcb);	1702	$w = AE::timer $w, 0, $rcb;
1254	} else {	1703	} else {
1255	# clean up...	1704	# clean up...
1256	undef $w;	1705	undef $w;
1257	undef $rcb;	1706	undef $rcb;
		1707	}
		1708	};
		1709
		1710	$w = AE::timer 0.05, 0, $rcb;
		1711
		1712	bless \\$cb, "AnyEvent::Base::idle"
1258	}	1713	};
		1714
		1715	*AnyEvent::Base::idle::DESTROY = sub {
		1716	undef $${$_[0]};
		1717	};
1259	};	1718	};
		1719	die if $@;
1260		1720
1261	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1721	&idle
1262
1263	bless \\$cb, "AnyEvent::Base::idle"
1264	}
1265
1266	sub AnyEvent::Base::idle::DESTROY {
1267	undef $${$_[0]};
1268	}	1722	}
1269		1723
1270	package AnyEvent::CondVar;	1724	package AnyEvent::CondVar;
1271		1725
1272	our @ISA = AnyEvent::CondVar::Base::;	1726	our @ISA = AnyEvent::CondVar::Base::;
1273		1727
1274	package AnyEvent::CondVar::Base;	1728	package AnyEvent::CondVar::Base;
1275		1729
1276	use overload	1730	#use overload
1277	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1731	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1278	fallback => 1;	1732	# fallback => 1;
		1733
		1734	# save 300+ kilobytes by dirtily hardcoding overloading
		1735	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1736	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1737	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1738	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1739
		1740	our $WAITING;
1279		1741
1280	sub _send {	1742	sub _send {
1281	# nop	1743	# nop
1282	}	1744	}
1283		1745
…		…
1296	sub ready {	1758	sub ready {
1297	$_[0]{_ae_sent}	1759	$_[0]{_ae_sent}
1298	}	1760	}
1299		1761
1300	sub _wait {	1762	sub _wait {
		1763	$WAITING
		1764	and !$_[0]{_ae_sent}
		1765	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1766
		1767	local $WAITING = 1;
1301	AnyEvent->one_event while !$_[0]{_ae_sent};	1768	AnyEvent->one_event while !$_[0]{_ae_sent};
1302	}	1769	}
1303		1770
1304	sub recv {	1771	sub recv {
1305	$_[0]->_wait;	1772	$_[0]->_wait;
…		…
1307	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1774	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1308	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1775	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1309	}	1776	}
1310		1777
1311	sub cb {	1778	sub cb {
1312	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1779	my $cv = shift;
		1780
		1781	@_
		1782	and $cv->{_ae_cb} = shift
		1783	and $cv->{_ae_sent}
		1784	and (delete $cv->{_ae_cb})->($cv);
		1785
1313	$_[0]{_ae_cb}	1786	$cv->{_ae_cb}
1314	}	1787	}
1315		1788
1316	sub begin {	1789	sub begin {
1317	++$_[0]{_ae_counter};	1790	++$_[0]{_ae_counter};
1318	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1791	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1346	so on.	1819	so on.
1347		1820
1348	=head1 ENVIRONMENT VARIABLES	1821	=head1 ENVIRONMENT VARIABLES
1349		1822
1350	The following environment variables are used by this module or its	1823	The following environment variables are used by this module or its
1351	submodules:	1824	submodules.
		1825
		1826	Note that AnyEvent will remove I<all> environment variables starting with
		1827	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1828	enabled.
1352		1829
1353	=over 4	1830	=over 4
1354		1831
1355	=item C<PERL_ANYEVENT_VERBOSE>	1832	=item C<PERL_ANYEVENT_VERBOSE>
1356		1833
…		…
1363	C<PERL_ANYEVENT_MODEL>.	1840	C<PERL_ANYEVENT_MODEL>.
1364		1841
1365	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1842	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1366	model it chooses.	1843	model it chooses.
1367		1844
		1845	When set to C<8> or higher, then AnyEvent will report extra information on
		1846	which optional modules it loads and how it implements certain features.
		1847
1368	=item C<PERL_ANYEVENT_STRICT>	1848	=item C<PERL_ANYEVENT_STRICT>
1369		1849
1370	AnyEvent does not do much argument checking by default, as thorough	1850	AnyEvent does not do much argument checking by default, as thorough
1371	argument checking is very costly. Setting this variable to a true value	1851	argument checking is very costly. Setting this variable to a true value
1372	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1852	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1373	check the arguments passed to most method calls. If it finds any problems	1853	check the arguments passed to most method calls. If it finds any problems,
1374	it will croak.	1854	it will croak.
1375		1855
1376	In other words, enables "strict" mode.	1856	In other words, enables "strict" mode.
1377		1857
1378	Unlike C<use strict>, it is definitely recommended ot keep it off in	1858	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1379	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1859	>>, it is definitely recommended to keep it off in production. Keeping
1380	developing programs can be very useful, however.	1860	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1861	can be very useful, however.
1381		1862
1382	=item C<PERL_ANYEVENT_MODEL>	1863	=item C<PERL_ANYEVENT_MODEL>
1383		1864
1384	This can be used to specify the event model to be used by AnyEvent, before	1865	This can be used to specify the event model to be used by AnyEvent, before
1385	auto detection and -probing kicks in. It must be a string consisting	1866	auto detection and -probing kicks in. It must be a string consisting
…		…
1428		1909
1429	=item C<PERL_ANYEVENT_MAX_FORKS>	1910	=item C<PERL_ANYEVENT_MAX_FORKS>
1430		1911
1431	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1912	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1432	will create in parallel.	1913	will create in parallel.
		1914
		1915	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1916
		1917	The default value for the C<max_outstanding> parameter for the default DNS
		1918	resolver - this is the maximum number of parallel DNS requests that are
		1919	sent to the DNS server.
		1920
		1921	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1922
		1923	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1924	configuration) in the default resolver. When set to the empty string, no
		1925	default config will be used.
		1926
		1927	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1928
		1929	When neither C<ca_file> nor C<ca_path> was specified during
		1930	L<AnyEvent::TLS> context creation, and either of these environment
		1931	variables exist, they will be used to specify CA certificate locations
		1932	instead of a system-dependent default.
		1933
		1934	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1935
		1936	When these are set to C<1>, then the respective modules are not
		1937	loaded. Mostly good for testing AnyEvent itself.
1433		1938
1434	=back	1939	=back
1435		1940
1436	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1941	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1437		1942
…		…
1495	warn "read: $input\n"; # output what has been read	2000	warn "read: $input\n"; # output what has been read
1496	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2001	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1497	},	2002	},
1498	);	2003	);
1499		2004
1500	my $time_watcher; # can only be used once
1501
1502	sub new_timer {
1503	$timer = AnyEvent->timer (after => 1, cb => sub {	2005	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1504	warn "timeout\n"; # print 'timeout' about every second	2006	warn "timeout\n"; # print 'timeout' at most every second
1505	&new_timer; # and restart the time
1506	});	2007	});
1507	}
1508
1509	new_timer; # create first timer
1510		2008
1511	$cv->recv; # wait until user enters /^q/i	2009	$cv->recv; # wait until user enters /^q/i
1512		2010
1513	=head1 REAL-WORLD EXAMPLE	2011	=head1 REAL-WORLD EXAMPLE
1514		2012
…		…
1587		2085
1588	The actual code goes further and collects all errors (C<die>s, exceptions)	2086	The actual code goes further and collects all errors (C<die>s, exceptions)
1589	that occurred during request processing. The C<result> method detects	2087	that occurred during request processing. The C<result> method detects
1590	whether an exception as thrown (it is stored inside the $txn object)	2088	whether an exception as thrown (it is stored inside the $txn object)
1591	and just throws the exception, which means connection errors and other	2089	and just throws the exception, which means connection errors and other
1592	problems get reported tot he code that tries to use the result, not in a	2090	problems get reported to the code that tries to use the result, not in a
1593	random callback.	2091	random callback.
1594		2092
1595	All of this enables the following usage styles:	2093	All of this enables the following usage styles:
1596		2094
1597	1. Blocking:	2095	1. Blocking:
…		…
1645	through AnyEvent. The benchmark creates a lot of timers (with a zero	2143	through AnyEvent. The benchmark creates a lot of timers (with a zero
1646	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2144	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1647	which it is), lets them fire exactly once and destroys them again.	2145	which it is), lets them fire exactly once and destroys them again.
1648		2146
1649	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2147	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1650	distribution.	2148	distribution. It uses the L<AE> interface, which makes a real difference
		2149	for the EV and Perl backends only.
1651		2150
1652	=head3 Explanation of the columns	2151	=head3 Explanation of the columns
1653		2152
1654	I<watcher> is the number of event watchers created/destroyed. Since	2153	I<watcher> is the number of event watchers created/destroyed. Since
1655	different event models feature vastly different performances, each event	2154	different event models feature vastly different performances, each event
…		…
1676	watcher.	2175	watcher.
1677		2176
1678	=head3 Results	2177	=head3 Results
1679		2178
1680	name watchers bytes create invoke destroy comment	2179	name watchers bytes create invoke destroy comment
1681	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2180	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1682	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2181	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1683	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2182	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1684	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2183	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1685	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2184	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1686	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2185	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2186	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2187	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1687	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2188	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1688	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2189	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1689	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2190	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1690	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2191	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1691		2192
1692	=head3 Discussion	2193	=head3 Discussion
1693		2194
1694	The benchmark does I<not> measure scalability of the event loop very	2195	The benchmark does I<not> measure scalability of the event loop very
1695	well. For example, a select-based event loop (such as the pure perl one)	2196	well. For example, a select-based event loop (such as the pure perl one)
…		…
1707	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2208	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1708	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2209	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1709	cycles with POE.	2210	cycles with POE.
1710		2211
1711	C<EV> is the sole leader regarding speed and memory use, which are both	2212	C<EV> is the sole leader regarding speed and memory use, which are both
1712	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2213	maximal/minimal, respectively. When using the L<AE> API there is zero
		2214	overhead (when going through the AnyEvent API create is about 5-6 times
		2215	slower, with other times being equal, so still uses far less memory than
1713	far less memory than any other event loop and is still faster than Event	2216	any other event loop and is still faster than Event natively).
1714	natively.
1715		2217
1716	The pure perl implementation is hit in a few sweet spots (both the	2218	The pure perl implementation is hit in a few sweet spots (both the
1717	constant timeout and the use of a single fd hit optimisations in the perl	2219	constant timeout and the use of a single fd hit optimisations in the perl
1718	interpreter and the backend itself). Nevertheless this shows that it	2220	interpreter and the backend itself). Nevertheless this shows that it
1719	adds very little overhead in itself. Like any select-based backend its	2221	adds very little overhead in itself. Like any select-based backend its
1720	performance becomes really bad with lots of file descriptors (and few of	2222	performance becomes really bad with lots of file descriptors (and few of
1721	them active), of course, but this was not subject of this benchmark.	2223	them active), of course, but this was not subject of this benchmark.
1722		2224
1723	The C<Event> module has a relatively high setup and callback invocation	2225	The C<Event> module has a relatively high setup and callback invocation
1724	cost, but overall scores in on the third place.	2226	cost, but overall scores in on the third place.
		2227
		2228	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2229	when using its pure perl backend.
1725		2230
1726	C<Glib>'s memory usage is quite a bit higher, but it features a	2231	C<Glib>'s memory usage is quite a bit higher, but it features a
1727	faster callback invocation and overall ends up in the same class as	2232	faster callback invocation and overall ends up in the same class as
1728	C<Event>. However, Glib scales extremely badly, doubling the number of	2233	C<Event>. However, Glib scales extremely badly, doubling the number of
1729	watchers increases the processing time by more than a factor of four,	2234	watchers increases the processing time by more than a factor of four,
…		…
1790	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2295	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1791	(1%) are active. This mirrors the activity of large servers with many	2296	(1%) are active. This mirrors the activity of large servers with many
1792	connections, most of which are idle at any one point in time.	2297	connections, most of which are idle at any one point in time.
1793		2298
1794	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2299	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1795	distribution.	2300	distribution. It uses the L<AE> interface, which makes a real difference
		2301	for the EV and Perl backends only.
1796		2302
1797	=head3 Explanation of the columns	2303	=head3 Explanation of the columns
1798		2304
1799	I<sockets> is the number of sockets, and twice the number of "servers" (as	2305	I<sockets> is the number of sockets, and twice the number of "servers" (as
1800	each server has a read and write socket end).	2306	each server has a read and write socket end).
…		…
1807	it to another server. This includes deleting the old timeout and creating	2313	it to another server. This includes deleting the old timeout and creating
1808	a new one that moves the timeout into the future.	2314	a new one that moves the timeout into the future.
1809		2315
1810	=head3 Results	2316	=head3 Results
1811		2317
1812	name sockets create request	2318	name sockets create request
1813	EV 20000 69.01 11.16	2319	EV 20000 62.66 7.99
1814	Perl 20000 73.32 35.87	2320	Perl 20000 68.32 32.64
1815	Event 20000 212.62 257.32	2321	IOAsync 20000 174.06 101.15 epoll
1816	Glib 20000 651.16 1896.30	2322	IOAsync 20000 174.67 610.84 poll
		2323	Event 20000 202.69 242.91
		2324	Glib 20000 557.01 1689.52
1817	POE 20000 349.67 12317.24 uses POE::Loop::Event	2325	POE 20000 341.54 12086.32 uses POE::Loop::Event
1818		2326
1819	=head3 Discussion	2327	=head3 Discussion
1820		2328
1821	This benchmark I<does> measure scalability and overall performance of the	2329	This benchmark I<does> measure scalability and overall performance of the
1822	particular event loop.	2330	particular event loop.
…		…
1824	EV is again fastest. Since it is using epoll on my system, the setup time	2332	EV is again fastest. Since it is using epoll on my system, the setup time
1825	is relatively high, though.	2333	is relatively high, though.
1826		2334
1827	Perl surprisingly comes second. It is much faster than the C-based event	2335	Perl surprisingly comes second. It is much faster than the C-based event
1828	loops Event and Glib.	2336	loops Event and Glib.
		2337
		2338	IO::Async performs very well when using its epoll backend, and still quite
		2339	good compared to Glib when using its pure perl backend.
1829		2340
1830	Event suffers from high setup time as well (look at its code and you will	2341	Event suffers from high setup time as well (look at its code and you will
1831	understand why). Callback invocation also has a high overhead compared to	2342	understand why). Callback invocation also has a high overhead compared to
1832	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2343	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1833	uses select or poll in basically all documented configurations.	2344	uses select or poll in basically all documented configurations.
…		…
1896	=item * C-based event loops perform very well with small number of	2407	=item * C-based event loops perform very well with small number of
1897	watchers, as the management overhead dominates.	2408	watchers, as the management overhead dominates.
1898		2409
1899	=back	2410	=back
1900		2411
		2412	=head2 THE IO::Lambda BENCHMARK
		2413
		2414	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2415	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2416	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2417	shouldn't come as a surprise to anybody). As such, the benchmark is
		2418	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2419	very optimal. But how would AnyEvent compare when used without the extra
		2420	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2421
		2422	The benchmark itself creates an echo-server, and then, for 500 times,
		2423	connects to the echo server, sends a line, waits for the reply, and then
		2424	creates the next connection. This is a rather bad benchmark, as it doesn't
		2425	test the efficiency of the framework or much non-blocking I/O, but it is a
		2426	benchmark nevertheless.
		2427
		2428	name runtime
		2429	Lambda/select 0.330 sec
		2430	+ optimized 0.122 sec
		2431	Lambda/AnyEvent 0.327 sec
		2432	+ optimized 0.138 sec
		2433	Raw sockets/select 0.077 sec
		2434	POE/select, components 0.662 sec
		2435	POE/select, raw sockets 0.226 sec
		2436	POE/select, optimized 0.404 sec
		2437
		2438	AnyEvent/select/nb 0.085 sec
		2439	AnyEvent/EV/nb 0.068 sec
		2440	+state machine 0.134 sec
		2441
		2442	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2443	benchmarks actually make blocking connects and use 100% blocking I/O,
		2444	defeating the purpose of an event-based solution. All of the newly
		2445	written AnyEvent benchmarks use 100% non-blocking connects (using
		2446	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2447	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2448	generally require a lot more bookkeeping and event handling than blocking
		2449	connects (which involve a single syscall only).
		2450
		2451	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2452	offers similar expressive power as POE and IO::Lambda, using conventional
		2453	Perl syntax. This means that both the echo server and the client are 100%
		2454	non-blocking, further placing it at a disadvantage.
		2455
		2456	As you can see, the AnyEvent + EV combination even beats the
		2457	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2458	backend easily beats IO::Lambda and POE.
		2459
		2460	And even the 100% non-blocking version written using the high-level (and
		2461	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2462	higher level ("unoptimised") abstractions by a large margin, even though
		2463	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
		2464
		2465	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2466	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2467	part of the IO::Lambda distribution and were used without any changes.
		2468
1901		2469
1902	=head1 SIGNALS	2470	=head1 SIGNALS
1903		2471
1904	AnyEvent currently installs handlers for these signals:	2472	AnyEvent currently installs handlers for these signals:
1905		2473
…		…
1908	=item SIGCHLD	2476	=item SIGCHLD
1909		2477
1910	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2478	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1911	emulation for event loops that do not support them natively. Also, some	2479	emulation for event loops that do not support them natively. Also, some
1912	event loops install a similar handler.	2480	event loops install a similar handler.
		2481
		2482	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2483	AnyEvent will reset it to default, to avoid losing child exit statuses.
1913		2484
1914	=item SIGPIPE	2485	=item SIGPIPE
1915		2486
1916	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2487	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1917	when AnyEvent gets loaded.	2488	when AnyEvent gets loaded.
…		…
1929		2500
1930	=back	2501	=back
1931		2502
1932	=cut	2503	=cut
1933		2504
		2505	undef $SIG{CHLD}
		2506	if $SIG{CHLD} eq 'IGNORE';
		2507
1934	$SIG{PIPE} = sub { }	2508	$SIG{PIPE} = sub { }
1935	unless defined $SIG{PIPE};	2509	unless defined $SIG{PIPE};
1936		2510
		2511	=head1 RECOMMENDED/OPTIONAL MODULES
		2512
		2513	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2514	it's built-in modules) are required to use it.
		2515
		2516	That does not mean that AnyEvent won't take advantage of some additional
		2517	modules if they are installed.
		2518
		2519	This section explains which additional modules will be used, and how they
		2520	affect AnyEvent's operation.
		2521
		2522	=over 4
		2523
		2524	=item L<Async::Interrupt>
		2525
		2526	This slightly arcane module is used to implement fast signal handling: To
		2527	my knowledge, there is no way to do completely race-free and quick
		2528	signal handling in pure perl. To ensure that signals still get
		2529	delivered, AnyEvent will start an interval timer to wake up perl (and
		2530	catch the signals) with some delay (default is 10 seconds, look for
		2531	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2532
		2533	If this module is available, then it will be used to implement signal
		2534	catching, which means that signals will not be delayed, and the event loop
		2535	will not be interrupted regularly, which is more efficient (and good for
		2536	battery life on laptops).
		2537
		2538	This affects not just the pure-perl event loop, but also other event loops
		2539	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2540
		2541	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2542	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2543	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2544	does nothing for those backends.
		2545
		2546	=item L<EV>
		2547
		2548	This module isn't really "optional", as it is simply one of the backend
		2549	event loops that AnyEvent can use. However, it is simply the best event
		2550	loop available in terms of features, speed and stability: It supports
		2551	the AnyEvent API optimally, implements all the watcher types in XS, does
		2552	automatic timer adjustments even when no monotonic clock is available,
		2553	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2554	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2555	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2556
		2557	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2558	then this module will do nothing for you.
		2559
		2560	=item L<Guard>
		2561
		2562	The guard module, when used, will be used to implement
		2563	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2564	lot less memory), but otherwise doesn't affect guard operation much. It is
		2565	purely used for performance.
		2566
		2567	=item L<JSON> and L<JSON::XS>
		2568
		2569	One of these modules is required when you want to read or write JSON data
		2570	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2571	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2572
		2573	=item L<Net::SSLeay>
		2574
		2575	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2576	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2577	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2578
		2579	=item L<Time::HiRes>
		2580
		2581	This module is part of perl since release 5.008. It will be used when the
		2582	chosen event library does not come with a timing source on it's own. The
		2583	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2584	try to use a monotonic clock for timing stability.
		2585
		2586	=back
		2587
1937		2588
1938	=head1 FORK	2589	=head1 FORK
1939		2590
1940	Most event libraries are not fork-safe. The ones who are usually are	2591	Most event libraries are not fork-safe. The ones who are usually are
1941	because they rely on inefficient but fork-safe C<select> or C<poll>	2592	because they rely on inefficient but fork-safe C<select> or C<poll> calls
1942	calls. Only L<EV> is fully fork-aware.	2593	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2594	are usually badly thought-out hacks that are incompatible with fork in
		2595	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2596	continue event-processing in both parent and child (or both, if you know
		2597	what you are doing).
		2598
		2599	This means that, in general, you cannot fork and do event processing in
		2600	the child if the event library was initialised before the fork (which
		2601	usually happens when the first AnyEvent watcher is created, or the library
		2602	is loaded).
1943		2603
1944	If you have to fork, you must either do so I<before> creating your first	2604	If you have to fork, you must either do so I<before> creating your first
1945	watcher OR you must not use AnyEvent at all in the child.	2605	watcher OR you must not use AnyEvent at all in the child OR you must do
		2606	something completely out of the scope of AnyEvent.
		2607
		2608	The problem of doing event processing in the parent I<and> the child
		2609	is much more complicated: even for backends that I<are> fork-aware or
		2610	fork-safe, their behaviour is not usually what you want: fork clones all
		2611	watchers, that means all timers, I/O watchers etc. are active in both
		2612	parent and child, which is almost never what you want. USing C<exec>
		2613	to start worker children from some kind of manage rprocess is usually
		2614	preferred, because it is much easier and cleaner, at the expense of having
		2615	to have another binary.
1946		2616
1947		2617
1948	=head1 SECURITY CONSIDERATIONS	2618	=head1 SECURITY CONSIDERATIONS
1949		2619
1950	AnyEvent can be forced to load any event model via	2620	AnyEvent can be forced to load any event model via
…		…
1962	use AnyEvent;	2632	use AnyEvent;
1963		2633
1964	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2634	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1965	be used to probe what backend is used and gain other information (which is	2635	be used to probe what backend is used and gain other information (which is
1966	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2636	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1967	$ENV{PERL_ANYEGENT_STRICT}.	2637	$ENV{PERL_ANYEVENT_STRICT}.
		2638
		2639	Note that AnyEvent will remove I<all> environment variables starting with
		2640	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2641	enabled.
1968		2642
1969		2643
1970	=head1 BUGS	2644	=head1 BUGS
1971		2645
1972	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2646	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
…		…
1984	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2658	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1985		2659
1986	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2660	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1987	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2661	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1988	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2662	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1989	L<AnyEvent::Impl::POE>.	2663	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1990		2664
1991	Non-blocking file handles, sockets, TCP clients and	2665	Non-blocking file handles, sockets, TCP clients and
1992	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2666	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1993		2667
1994	Asynchronous DNS: L<AnyEvent::DNS>.	2668	Asynchronous DNS: L<AnyEvent::DNS>.
1995		2669
1996	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2670	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2671	L<Coro::Event>,
1997		2672
1998	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2673	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2674	L<AnyEvent::HTTP>.
1999		2675
2000		2676
2001	=head1 AUTHOR	2677	=head1 AUTHOR
2002		2678
2003	Marc Lehmann <schmorp@schmorp.de>	2679	Marc Lehmann <schmorp@schmorp.de>

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