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Revision 1.210 by root, Wed May 13 15:19:43 2009 UTC vs.
Revision 1.323 by root, Thu May 20 21:22:20 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 instrument to do that is called a "condition variable", so called
467	because they represent a condition that must become true.	562	because they represent a condition that must become true.
468		563
		564	Now is probably a good time to look at the examples further below.
		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"
…		…
481	Condition variables are similar to callbacks, except that you can	577	Condition variables are similar to callbacks, except that you can
482	optionally wait for them. They can also be called merge points - points	578	optionally wait for them. They can also be called merge points - points
483	in time where multiple outstanding events have been processed. And yet	579	in time where multiple outstanding events have been processed. And yet
484	another way to call them is transactions - each condition variable can be	580	another way to call them is transactions - each condition variable can be
485	used to represent a transaction, which finishes at some point and delivers	581	used to represent a transaction, which finishes at some point and delivers
486	a result.	582	a result. And yet some people know them as "futures" - a promise to
		583	compute/deliver something that you can wait for.
487		584
488	Condition variables are very useful to signal that something has finished,	585	Condition variables are very useful to signal that something has finished,
489	for example, if you write a module that does asynchronous http requests,	586	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	587	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	588	availability of results. The user can either act when the callback is
…		…
512	eventually calls C<< -> send >>, and the "consumer side", which waits	609	eventually calls C<< -> send >>, and the "consumer side", which waits
513	for the send to occur.	610	for the send to occur.
514		611
515	Example: wait for a timer.	612	Example: wait for a timer.
516		613
517	# wait till the result is ready	614	# condition: "wait till the timer is fired"
518	my $result_ready = AnyEvent->condvar;	615	my $timer_fired = AnyEvent->condvar;
519		616
520	# do something such as adding a timer	617	# create the timer - we could wait for, say
521	# or socket watcher the calls $result_ready->send	618	# a handle becomign ready, or even an
522	# when the "result" is ready.	619	# AnyEvent::HTTP request to finish, but
523	# in this case, we simply use a timer:	620	# in this case, we simply use a timer:
524	my $w = AnyEvent->timer (	621	my $w = AnyEvent->timer (
525	after => 1,	622	after => 1,
526	cb => sub { $result_ready->send },	623	cb => sub { $timer_fired->send },
527	);	624	);
528		625
529	# this "blocks" (while handling events) till the callback	626	# this "blocks" (while handling events) till the callback
530	# calls send	627	# calls ->send
531	$result_ready->recv;	628	$timer_fired->recv;
532		629
533	Example: wait for a timer, but take advantage of the fact that	630	Example: wait for a timer, but take advantage of the fact that condition
534	condition variables are also code references.	631	variables are also callable directly.
535		632
536	my $done = AnyEvent->condvar;	633	my $done = AnyEvent->condvar;
537	my $delay = AnyEvent->timer (after => 5, cb => $done);	634	my $delay = AnyEvent->timer (after => 5, cb => $done);
538	$done->recv;	635	$done->recv;
539		636
…		…
545		642
546	...	643	...
547		644
548	my @info = $couchdb->info->recv;	645	my @info = $couchdb->info->recv;
549		646
550	And this is how you would just ste a callback to be called whenever the	647	And this is how you would just set a callback to be called whenever the
551	results are available:	648	results are available:
552		649
553	$couchdb->info->cb (sub {	650	$couchdb->info->cb (sub {
554	my @info = $_[0]->recv;	651	my @info = $_[0]->recv;
555	});	652	});
…		…
573	immediately from within send.	670	immediately from within send.
574		671
575	Any arguments passed to the C<send> call will be returned by all	672	Any arguments passed to the C<send> call will be returned by all
576	future C<< ->recv >> calls.	673	future C<< ->recv >> calls.
577		674
578	Condition variables are overloaded so one can call them directly	675	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	676	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	677	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		678
587	=item $cv->croak ($error)	679	=item $cv->croak ($error)
588		680
589	Similar to send, but causes all call's to C<< ->recv >> to invoke	681	Similar to send, but causes all call's to C<< ->recv >> to invoke
590	C<Carp::croak> with the given error message/object/scalar.	682	C<Carp::croak> with the given error message/object/scalar.
591		683
592	This can be used to signal any errors to the condition variable	684	This can be used to signal any errors to the condition variable
593	user/consumer.	685	user/consumer. Doing it this way instead of calling C<croak> directly
		686	delays the error detetcion, but has the overwhelmign advantage that it
		687	diagnoses the error at the place where the result is expected, and not
		688	deep in some event clalback without connection to the actual code causing
		689	the problem.
594		690
595	=item $cv->begin ([group callback])	691	=item $cv->begin ([group callback])
596		692
597	=item $cv->end	693	=item $cv->end
598
599	These two methods are EXPERIMENTAL and MIGHT CHANGE.
600		694
601	These two methods can be used to combine many transactions/events into	695	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	696	one. For example, a function that pings many hosts in parallel might want
603	to use a condition variable for the whole process.	697	to use a condition variable for the whole process.
604		698
605	Every call to C<< ->begin >> will increment a counter, and every call to	699	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	700	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	701	>>, 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	702	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.	703	>>, but that is not required. If no group callback was set, C<send> will
		704	be called without any arguments.
610		705
611	Let's clarify this with the ping example:	706	You can think of C<< $cv->send >> giving you an OR condition (one call
		707	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		708	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		709
		710	Let's start with a simple example: you have two I/O watchers (for example,
		711	STDOUT and STDERR for a program), and you want to wait for both streams to
		712	close before activating a condvar:
612		713
613	my $cv = AnyEvent->condvar;	714	my $cv = AnyEvent->condvar;
614		715
		716	$cv->begin; # first watcher
		717	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		718	defined sysread $fh1, my $buf, 4096
		719	or $cv->end;
		720	});
		721
		722	$cv->begin; # second watcher
		723	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		724	defined sysread $fh2, my $buf, 4096
		725	or $cv->end;
		726	});
		727
		728	$cv->recv;
		729
		730	This works because for every event source (EOF on file handle), there is
		731	one call to C<begin>, so the condvar waits for all calls to C<end> before
		732	sending.
		733
		734	The ping example mentioned above is slightly more complicated, as the
		735	there are results to be passwd back, and the number of tasks that are
		736	begung can potentially be zero:
		737
		738	my $cv = AnyEvent->condvar;
		739
615	my %result;	740	my %result;
616	$cv->begin (sub { $cv->send (\%result) });	741	$cv->begin (sub { shift->send (\%result) });
617		742
618	for my $host (@list_of_hosts) {	743	for my $host (@list_of_hosts) {
619	$cv->begin;	744	$cv->begin;
620	ping_host_then_call_callback $host, sub {	745	ping_host_then_call_callback $host, sub {
621	$result{$host} = ...;	746	$result{$host} = ...;
…		…
636	loop, which serves two important purposes: first, it sets the callback	761	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	762	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	763	C<send> is called even when C<no> hosts are being pinged (the loop
639	doesn't execute once).	764	doesn't execute once).
640		765
641	This is the general pattern when you "fan out" into multiple subrequests:	766	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>	767	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	768	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>.	769	subrequest you start, call C<begin> and for each subrequest you finish,
		770	call C<end>.
645		771
646	=back	772	=back
647		773
648	=head3 METHODS FOR CONSUMERS	774	=head3 METHODS FOR CONSUMERS
649		775
…		…
665	function will call C<croak>.	791	function will call C<croak>.
666		792
667	In list context, all parameters passed to C<send> will be returned,	793	In list context, all parameters passed to C<send> will be returned,
668	in scalar context only the first one will be returned.	794	in scalar context only the first one will be returned.
669		795
		796	Note that doing a blocking wait in a callback is not supported by any
		797	event loop, that is, recursive invocation of a blocking C<< ->recv
		798	>> is not allowed, and the C<recv> call will C<croak> if such a
		799	condition is detected. This condition can be slightly loosened by using
		800	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		801	any thread that doesn't run the event loop itself.
		802
670	Not all event models support a blocking wait - some die in that case	803	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	804	(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	805	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	806	caller decide whether the call will block or not (for example, by coupling
674	condition variables with some kind of request results and supporting	807	condition variables with some kind of request results and supporting
675	callbacks so the caller knows that getting the result will not block,	808	callbacks so the caller knows that getting the result will not block,
676	while still supporting blocking waits if the caller so desires).	809	while still supporting blocking waits if the caller so desires).
677		810
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	811	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	812	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	813	time). This will work even when the event loop does not support blocking
692	waits otherwise.	814	waits otherwise.
693		815
…		…
699	=item $cb = $cv->cb ($cb->($cv))	821	=item $cb = $cv->cb ($cb->($cv))
700		822
701	This is a mutator function that returns the callback set and optionally	823	This is a mutator function that returns the callback set and optionally
702	replaces it before doing so.	824	replaces it before doing so.
703		825
704	The callback will be called when the condition becomes "true", i.e. when	826	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	827	"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	828	the only argument being the condition variable itself. Calling C<recv>
707	is guaranteed not to block.	829	inside the callback or at any later time is guaranteed not to block.
708		830
709	=back	831	=back
710		832
		833	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		834
		835	The available backend classes are (every class has its own manpage):
		836
		837	=over 4
		838
		839	=item Backends that are autoprobed when no other event loop can be found.
		840
		841	EV is the preferred backend when no other event loop seems to be in
		842	use. If EV is not installed, then AnyEvent will fall back to its own
		843	pure-perl implementation, which is available everywhere as it comes with
		844	AnyEvent itself.
		845
		846	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		847	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		848
		849	=item Backends that are transparently being picked up when they are used.
		850
		851	These will be used when they are currently loaded when the first watcher
		852	is created, in which case it is assumed that the application is using
		853	them. This means that AnyEvent will automatically pick the right backend
		854	when the main program loads an event module before anything starts to
		855	create watchers. Nothing special needs to be done by the main program.
		856
		857	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		858	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		859	AnyEvent::Impl::Tk based on Tk, very broken.
		860	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		861	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		862	AnyEvent::Impl::Irssi used when running within irssi.
		863
		864	=item Backends with special needs.
		865
		866	Qt requires the Qt::Application to be instantiated first, but will
		867	otherwise be picked up automatically. As long as the main program
		868	instantiates the application before any AnyEvent watchers are created,
		869	everything should just work.
		870
		871	AnyEvent::Impl::Qt based on Qt.
		872
		873	Support for IO::Async can only be partial, as it is too broken and
		874	architecturally limited to even support the AnyEvent API. It also
		875	is the only event loop that needs the loop to be set explicitly, so
		876	it can only be used by a main program knowing about AnyEvent. See
		877	L<AnyEvent::Impl::Async> for the gory details.
		878
		879	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		880
		881	=item Event loops that are indirectly supported via other backends.
		882
		883	Some event loops can be supported via other modules:
		884
		885	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		886
		887	B<WxWidgets> has no support for watching file handles. However, you can
		888	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		889	polls 20 times per second, which was considered to be too horrible to even
		890	consider for AnyEvent.
		891
		892	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		893	backend, so it can be supported through POE.
		894
		895	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		896	load L<POE> when detecting them, in the hope that POE will pick them up,
		897	in which case everything will be automatic.
		898
		899	=back
		900
711	=head1 GLOBAL VARIABLES AND FUNCTIONS	901	=head1 GLOBAL VARIABLES AND FUNCTIONS
712		902
		903	These are not normally required to use AnyEvent, but can be useful to
		904	write AnyEvent extension modules.
		905
713	=over 4	906	=over 4
714		907
715	=item $AnyEvent::MODEL	908	=item $AnyEvent::MODEL
716		909
717	Contains C<undef> until the first watcher is being created. Then it	910	Contains C<undef> until the first watcher is being created, before the
		911	backend has been autodetected.
		912
718	contains the event model that is being used, which is the name of the	913	Afterwards it contains the event model that is being used, which is the
719	Perl class implementing the model. This class is usually one of the	914	name of the Perl class implementing the model. This class is usually one
720	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	915	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
721	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	916	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
722		917	will be C<urxvt::anyevent>).
723	The known classes so far are:
724
725	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
726	AnyEvent::Impl::Event based on Event, second best choice.
727	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
728	AnyEvent::Impl::Glib based on Glib, third-best choice.
729	AnyEvent::Impl::Tk based on Tk, very bad choice.
730	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
731	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
732	AnyEvent::Impl::POE based on POE, not generic enough for full support.
733
734	There is no support for WxWidgets, as WxWidgets has no support for
735	watching file handles. However, you can use WxWidgets through the
736	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
737	second, which was considered to be too horrible to even consider for
738	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
739	it's adaptor.
740
741	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
742	autodetecting them.
743		918
744	=item AnyEvent::detect	919	=item AnyEvent::detect
745		920
746	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	921	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
747	if necessary. You should only call this function right before you would	922	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	923	have created an AnyEvent watcher anyway, that is, as late as possible at
749	runtime.	924	runtime, and not e.g. while initialising of your module.
		925
		926	If you need to do some initialisation before AnyEvent watchers are
		927	created, use C<post_detect>.
750		928
751	=item $guard = AnyEvent::post_detect { BLOCK }	929	=item $guard = AnyEvent::post_detect { BLOCK }
752		930
753	Arranges for the code block to be executed as soon as the event model is	931	Arranges for the code block to be executed as soon as the event model is
754	autodetected (or immediately if this has already happened).	932	autodetected (or immediately if this has already happened).
755		933
		934	The block will be executed I<after> the actual backend has been detected
		935	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		936	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		937	other initialisations - see the sources of L<AnyEvent::Strict> or
		938	L<AnyEvent::AIO> to see how this is used.
		939
		940	The most common usage is to create some global watchers, without forcing
		941	event module detection too early, for example, L<AnyEvent::AIO> creates
		942	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		943	avoid autodetecting the event module at load time.
		944
756	If called in scalar or list context, then it creates and returns an object	945	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	946	that automatically removes the callback again when it is destroyed (or
		947	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
758	L<Coro::BDB> for a case where this is useful.	948	a case where this is useful.
		949
		950	Example: Create a watcher for the IO::AIO module and store it in
		951	C<$WATCHER>. Only do so after the event loop is initialised, though.
		952
		953	our WATCHER;
		954
		955	my $guard = AnyEvent::post_detect {
		956	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		957	};
		958
		959	# the ||= is important in case post_detect immediately runs the block,
		960	# as to not clobber the newly-created watcher. assigning both watcher and
		961	# post_detect guard to the same variable has the advantage of users being
		962	# able to just C<undef $WATCHER> if the watcher causes them grief.
		963
		964	$WATCHER ||= $guard;
759		965
760	=item @AnyEvent::post_detect	966	=item @AnyEvent::post_detect
761		967
762	If there are any code references in this array (you can C<push> to it	968	If there are any code references in this array (you can C<push> to it
763	before or after loading AnyEvent), then they will called directly after	969	before or after loading AnyEvent), then they will called directly after
764	the event loop has been chosen.	970	the event loop has been chosen.
765		971
766	You should check C<$AnyEvent::MODEL> before adding to this array, though:	972	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,	973	if it is defined then the event loop has already been detected, and the
768	and the array will be ignored.	974	array will be ignored.
769		975
770	Best use C<AnyEvent::post_detect { BLOCK }> instead.	976	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		977	it, as it takes care of these details.
		978
		979	This variable is mainly useful for modules that can do something useful
		980	when AnyEvent is used and thus want to know when it is initialised, but do
		981	not need to even load it by default. This array provides the means to hook
		982	into AnyEvent passively, without loading it.
		983
		984	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		985	together, you could put this into Coro (this is the actual code used by
		986	Coro to accomplish this):
		987
		988	if (defined $AnyEvent::MODEL) {
		989	# AnyEvent already initialised, so load Coro::AnyEvent
		990	require Coro::AnyEvent;
		991	} else {
		992	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		993	# as soon as it is
		994	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		995	}
771		996
772	=back	997	=back
773		998
774	=head1 WHAT TO DO IN A MODULE	999	=head1 WHAT TO DO IN A MODULE
775		1000
…		…
830		1055
831		1056
832	=head1 OTHER MODULES	1057	=head1 OTHER MODULES
833		1058
834	The following is a non-exhaustive list of additional modules that use	1059	The following is a non-exhaustive list of additional modules that use
835	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1060	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	1061	modules and other event loops in the same program. Some of the modules
837	available via CPAN.	1062	come with AnyEvent, most are available via CPAN.
838		1063
839	=over 4	1064	=over 4
840		1065
841	=item L<AnyEvent::Util>	1066	=item L<AnyEvent::Util>
842		1067
…		…
851		1076
852	=item L<AnyEvent::Handle>	1077	=item L<AnyEvent::Handle>
853		1078
854	Provide read and write buffers, manages watchers for reads and writes,	1079	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	1080	supports raw and formatted I/O, I/O queued and fully transparent and
856	non-blocking SSL/TLS.	1081	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
857		1082
858	=item L<AnyEvent::DNS>	1083	=item L<AnyEvent::DNS>
859		1084
860	Provides rich asynchronous DNS resolver capabilities.	1085	Provides rich asynchronous DNS resolver capabilities.
861		1086
		1087	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1088
		1089	Implement event-based interfaces to the protocols of the same name (for
		1090	the curious, IGS is the International Go Server and FCP is the Freenet
		1091	Client Protocol).
		1092
		1093	=item L<AnyEvent::Handle::UDP>
		1094
		1095	Here be danger!
		1096
		1097	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1098	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1099	it's use of a stream-based API with a protocol that isn't streamable, that
		1100	the only way to improve it is to delete it.
		1101
		1102	It features data corruption (but typically only under load) and general
		1103	confusion. On top, the author is not only clueless about UDP but also
		1104	fact-resistant - some gems of his understanding: "connect doesn't work
		1105	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1106	packets", "I don't need to implement proper error checking as UDP doesn't
		1107	support error checking" and so on - he doesn't even understand what's
		1108	wrong with his module when it is explained to him.
		1109
862	=item L<AnyEvent::HTTP>	1110	=item L<AnyEvent::DBI>
863		1111
864	A simple-to-use HTTP library that is capable of making a lot of concurrent	1112	Executes L<DBI> requests asynchronously in a proxy process for you,
865	HTTP requests.	1113	notifying you in an event-bnased way when the operation is finished.
		1114
		1115	=item L<AnyEvent::AIO>
		1116
		1117	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1118	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1119	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1120	file I/O, and much more.
866		1121
867	=item L<AnyEvent::HTTPD>	1122	=item L<AnyEvent::HTTPD>
868		1123
869	Provides a simple web application server framework.	1124	A simple embedded webserver.
870		1125
871	=item L<AnyEvent::FastPing>	1126	=item L<AnyEvent::FastPing>
872		1127
873	The fastest ping in the west.	1128	The fastest ping in the west.
874		1129
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>	1130	=item L<Coro>
917		1131
918	Has special support for AnyEvent via L<Coro::AnyEvent>.	1132	Has special support for AnyEvent via L<Coro::AnyEvent>.
919		1133
920	=item L<IO::Lambda>
921
922	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
923
924	=back	1134	=back
925		1135
926	=cut	1136	=cut
927		1137
928	package AnyEvent;	1138	package AnyEvent;
929		1139
930	no warnings;	1140	# basically a tuned-down version of common::sense
931	use strict qw(vars subs);	1141	sub common_sense {
		1142	# from common:.sense 1.0
		1143	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
		1144	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1145	$^H |= 0x00000600;
		1146	}
932		1147
		1148	BEGIN { AnyEvent::common_sense }
		1149
933	use Carp;	1150	use Carp ();
934		1151
935	our $VERSION = 4.41;	1152	our $VERSION = '5.261';
936	our $MODEL;	1153	our $MODEL;
937		1154
938	our $AUTOLOAD;	1155	our $AUTOLOAD;
939	our @ISA;	1156	our @ISA;
940		1157
941	our @REGISTRY;	1158	our @REGISTRY;
942		1159
943	our $WIN32;	1160	our $VERBOSE;
944		1161
945	BEGIN {	1162	BEGIN {
946	my $win32 = ! ! ($^O =~ /mswin32/i);	1163	require "AnyEvent/constants.pl";
947	eval "sub WIN32(){ $win32 }";
948	}
949		1164
		1165	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
		1166
		1167	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1168	if ${^TAINT};
		1169
950	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1170	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1171
		1172	}
		1173
		1174	our $MAX_SIGNAL_LATENCY = 10;
951		1175
952	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1176	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
953		1177
954	{	1178	{
955	my $idx;	1179	my $idx;
…		…
957	for reverse split /\s*,\s*/,	1181	for reverse split /\s*,\s*/,
958	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1182	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
959	}	1183	}
960		1184
961	my @models = (	1185	my @models = (
962	[EV:: => AnyEvent::Impl::EV::],	1186	[EV:: => AnyEvent::Impl::EV:: , 1],
963	[Event:: => AnyEvent::Impl::Event::],
964	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1187	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
965	# everything below here will not be autoprobed	1188	# everything below here will not (normally) be autoprobed
966	# as the pureperl backend should work everywhere	1189	# as the pureperl backend should work everywhere
967	# and is usually faster	1190	# and is usually faster
		1191	[Event:: => AnyEvent::Impl::Event::, 1],
		1192	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1193	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1194	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
968	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1195	[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	1196	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
972	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1197	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
973	[Wx:: => AnyEvent::Impl::POE::],	1198	[Wx:: => AnyEvent::Impl::POE::],
974	[Prima:: => AnyEvent::Impl::POE::],	1199	[Prima:: => AnyEvent::Impl::POE::],
		1200	# IO::Async is just too broken - we would need workarounds for its
		1201	# byzantine signal and broken child handling, among others.
		1202	# IO::Async is rather hard to detect, as it doesn't have any
		1203	# obvious default class.
		1204	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1205	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1206	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1207	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
975	);	1208	);
976		1209
977	our %method = map +($_ => 1),	1210	our %method = map +($_ => 1),
978	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1211	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
979		1212
980	our @post_detect;	1213	our @post_detect;
981		1214
982	sub post_detect(&) {	1215	sub post_detect(&) {
983	my ($cb) = @_;	1216	my ($cb) = @_;
984		1217
985	if ($MODEL) {
986	$cb->();
987
988	1
989	} else {
990	push @post_detect, $cb;	1218	push @post_detect, $cb;
991		1219
992	defined wantarray	1220	defined wantarray
993	? bless \$cb, "AnyEvent::Util::postdetect"	1221	? bless \$cb, "AnyEvent::Util::postdetect"
994	: ()	1222	: ()
995	}
996	}	1223	}
997		1224
998	sub AnyEvent::Util::postdetect::DESTROY {	1225	sub AnyEvent::Util::postdetect::DESTROY {
999	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1226	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1000	}	1227	}
1001		1228
1002	sub detect() {	1229	sub detect() {
		1230	# free some memory
		1231	*detect = sub () { $MODEL };
		1232
		1233	local $!; # for good measure
		1234	local $SIG{__DIE__};
		1235
		1236	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1237	my $model = "AnyEvent::Impl::$1";
		1238	if (eval "require $model") {
		1239	$MODEL = $model;
		1240	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1241	} else {
		1242	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1243	}
		1244	}
		1245
		1246	# check for already loaded models
1003	unless ($MODEL) {	1247	unless ($MODEL) {
1004	no strict 'refs';	1248	for (@REGISTRY, @models) {
1005	local $SIG{__DIE__};	1249	my ($package, $model) = @$_;
1006		1250	if (${"$package\::VERSION"} > 0) {
1007	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1008	my $model = "AnyEvent::Impl::$1";
1009	if (eval "require $model") {	1251	if (eval "require $model") {
1010	$MODEL = $model;	1252	$MODEL = $model;
1011	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1253	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1012	} else {	1254	last;
1013	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1255	}
1014	}	1256	}
1015	}	1257	}
1016		1258
1017	# check for already loaded models
1018	unless ($MODEL) {	1259	unless ($MODEL) {
		1260	# try to autoload a model
1019	for (@REGISTRY, @models) {	1261	for (@REGISTRY, @models) {
1020	my ($package, $model) = @$_;	1262	my ($package, $model, $autoload) = @$_;
		1263	if (
		1264	$autoload
		1265	and eval "require $package"
1021	if (${"$package\::VERSION"} > 0) {	1266	and ${"$package\::VERSION"} > 0
1022	if (eval "require $model") {	1267	and eval "require $model"
		1268	) {
1023	$MODEL = $model;	1269	$MODEL = $model;
1024	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1270	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1025	last;	1271	last;
1026	}
1027	}	1272	}
1028	}	1273	}
1029		1274
1030	unless ($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	1275	$MODEL
1045	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1276	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
1046	}
1047	}	1277	}
1048
1049	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1050
1051	unshift @ISA, $MODEL;
1052
1053	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1054
1055	(shift @post_detect)->() while @post_detect;
1056	}	1278	}
		1279
		1280	@models = (); # free probe data
		1281
		1282	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1283	unshift @ISA, $MODEL;
		1284
		1285	# now nuke some methods that are overriden by the backend.
		1286	# SUPER is not allowed.
		1287	for (qw(time signal child idle)) {
		1288	undef &{"AnyEvent::Base::$_"}
		1289	if defined &{"$MODEL\::$_"};
		1290	}
		1291
		1292	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1293
		1294	(shift @post_detect)->() while @post_detect;
		1295
		1296	*post_detect = sub(&) {
		1297	shift->();
		1298
		1299	undef
		1300	};
1057		1301
1058	$MODEL	1302	$MODEL
1059	}	1303	}
1060		1304
1061	sub AUTOLOAD {	1305	sub AUTOLOAD {
1062	(my $func = $AUTOLOAD) =~ s/.*://;	1306	(my $func = $AUTOLOAD) =~ s/.*://;
1063		1307
1064	$method{$func}	1308	$method{$func}
1065	or croak "$func: not a valid method for AnyEvent objects";	1309	or Carp::croak "$func: not a valid AnyEvent class method";
1066		1310
1067	detect unless $MODEL;	1311	detect;
1068		1312
1069	my $class = shift;	1313	my $class = shift;
1070	$class->$func (@_);	1314	$class->$func (@_);
1071	}	1315	}
1072		1316
1073	# utility function to dup a filehandle. this is used by many backends	1317	# utility function to dup a filehandle. this is used by many backends
1074	# to support binding more than one watcher per filehandle (they usually	1318	# 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).	1319	# allow only one watcher per fd, so we dup it to get a different one).
1076	sub _dupfh($$$$) {	1320	sub _dupfh($$;$$) {
1077	my ($poll, $fh, $r, $w) = @_;	1321	my ($poll, $fh, $r, $w) = @_;
1078		1322
1079	# cygwin requires the fh mode to be matching, unix doesn't	1323	# cygwin requires the fh mode to be matching, unix doesn't
1080	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1324	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1081	: $poll eq "w" ? ($w, ">")
1082	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1083		1325
1084	open my $fh2, "$mode&" . fileno $fh	1326	open my $fh2, $mode, $fh
1085	or die "cannot dup() filehandle: $!,";	1327	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1086		1328
1087	# we assume CLOEXEC is already set by perl in all important cases	1329	# we assume CLOEXEC is already set by perl in all important cases
1088		1330
1089	($fh2, $rw)	1331	($fh2, $rw)
1090	}	1332	}
1091		1333
		1334	=head1 SIMPLIFIED AE API
		1335
		1336	Starting with version 5.0, AnyEvent officially supports a second, much
		1337	simpler, API that is designed to reduce the calling, typing and memory
		1338	overhead by using function call syntax and a fixed number of parameters.
		1339
		1340	See the L<AE> manpage for details.
		1341
		1342	=cut
		1343
		1344	package AE;
		1345
		1346	our $VERSION = $AnyEvent::VERSION;
		1347
		1348	# fall back to the main API by default - backends and AnyEvent::Base
		1349	# implementations can overwrite these.
		1350
		1351	sub io($$$) {
		1352	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1353	}
		1354
		1355	sub timer($$$) {
		1356	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1357	}
		1358
		1359	sub signal($$) {
		1360	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1361	}
		1362
		1363	sub child($$) {
		1364	AnyEvent->child (pid => $_[0], cb => $_[1])
		1365	}
		1366
		1367	sub idle($) {
		1368	AnyEvent->idle (cb => $_[0])
		1369	}
		1370
		1371	sub cv(;&) {
		1372	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1373	}
		1374
		1375	sub now() {
		1376	AnyEvent->now
		1377	}
		1378
		1379	sub now_update() {
		1380	AnyEvent->now_update
		1381	}
		1382
		1383	sub time() {
		1384	AnyEvent->time
		1385	}
		1386
1092	package AnyEvent::Base;	1387	package AnyEvent::Base;
1093		1388
1094	# default implementations for many methods	1389	# default implementations for many methods
1095		1390
1096	BEGIN {	1391	sub time {
		1392	eval q{ # poor man's autoloading {}
		1393	# probe for availability of Time::HiRes
1097	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1394	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1395	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1098	*_time = \&Time::HiRes::time;	1396	*AE::time = \&Time::HiRes::time;
1099	# if (eval "use POSIX (); (POSIX::times())...	1397	# if (eval "use POSIX (); (POSIX::times())...
1100	} else {	1398	} else {
		1399	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1101	*_time = sub { time }; # epic fail	1400	*AE::time = sub (){ time }; # epic fail
		1401	}
		1402
		1403	*time = sub { AE::time }; # different prototypes
		1404	};
		1405	die if $@;
		1406
		1407	&time
		1408	}
		1409
		1410	*now = \&time;
		1411
		1412	sub now_update { }
		1413
		1414	# default implementation for ->condvar
		1415
		1416	sub condvar {
		1417	eval q{ # poor man's autoloading {}
		1418	*condvar = sub {
		1419	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1420	};
		1421
		1422	*AE::cv = sub (;&) {
		1423	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1424	};
		1425	};
		1426	die if $@;
		1427
		1428	&condvar
		1429	}
		1430
		1431	# default implementation for ->signal
		1432
		1433	our $HAVE_ASYNC_INTERRUPT;
		1434
		1435	sub _have_async_interrupt() {
		1436	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1437	&& eval "use Async::Interrupt 1.02 (); 1")
		1438	unless defined $HAVE_ASYNC_INTERRUPT;
		1439
		1440	$HAVE_ASYNC_INTERRUPT
		1441	}
		1442
		1443	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1444	our (%SIG_ASY, %SIG_ASY_W);
		1445	our ($SIG_COUNT, $SIG_TW);
		1446
		1447	# install a dummy wakeup watcher to reduce signal catching latency
		1448	# used by Impls
		1449	sub _sig_add() {
		1450	unless ($SIG_COUNT++) {
		1451	# try to align timer on a full-second boundary, if possible
		1452	my $NOW = AE::now;
		1453
		1454	$SIG_TW = AE::timer
		1455	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1456	$MAX_SIGNAL_LATENCY,
		1457	sub { } # just for the PERL_ASYNC_CHECK
		1458	;
1102	}	1459	}
1103	}	1460	}
1104		1461
1105	sub time { _time }	1462	sub _sig_del {
1106	sub now { _time }	1463	undef $SIG_TW
1107	sub now_update { }	1464	unless --$SIG_COUNT;
1108
1109	# default implementation for ->condvar
1110
1111	sub condvar {
1112	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1113	}	1465	}
1114		1466
1115	# default implementation for ->signal	1467	our $_sig_name_init; $_sig_name_init = sub {
		1468	eval q{ # poor man's autoloading {}
		1469	undef $_sig_name_init;
1116		1470
1117	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1471	if (_have_async_interrupt) {
		1472	*sig2num = \&Async::Interrupt::sig2num;
		1473	*sig2name = \&Async::Interrupt::sig2name;
		1474	} else {
		1475	require Config;
1118		1476
1119	sub _signal_exec {	1477	my %signame2num;
1120	sysread $SIGPIPE_R, my $dummy, 4;	1478	@signame2num{ split ' ', $Config::Config{sig_name} }
		1479	= split ' ', $Config::Config{sig_num};
1121		1480
1122	while (%SIG_EV) {	1481	my @signum2name;
1123	for (keys %SIG_EV) {	1482	@signum2name[values %signame2num] = keys %signame2num;
1124	delete $SIG_EV{$_};	1483
1125	$_->() for values %{ $SIG_CB{$_} || {} };	1484	*sig2num = sub($) {
		1485	$_[0] > 0 ? shift : $signame2num{+shift}
		1486	};
		1487	*sig2name = sub ($) {
		1488	$_[0] > 0 ? $signum2name[+shift] : shift
		1489	};
1126	}	1490	}
1127	}	1491	};
1128	}	1492	die if $@;
		1493	};
		1494
		1495	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1496	sub sig2name($) { &$_sig_name_init; &sig2name }
1129		1497
1130	sub signal {	1498	sub signal {
1131	my (undef, %arg) = @_;	1499	eval q{ # poor man's autoloading {}
		1500	# probe for availability of Async::Interrupt
		1501	if (_have_async_interrupt) {
		1502	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1132		1503
1133	unless ($SIGPIPE_R) {	1504	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1134	require Fcntl;	1505	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1135		1506
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 {	1507	} else {
		1508	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1509
		1510	if (AnyEvent::WIN32) {
		1511	require AnyEvent::Util;
		1512
		1513	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1514	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1515	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1516	} else {
1143	pipe $SIGPIPE_R, $SIGPIPE_W;	1517	pipe $SIGPIPE_R, $SIGPIPE_W;
1144	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1518	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	1519	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1520
		1521	# not strictly required, as $^F is normally 2, but let's make sure...
		1522	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1523	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1524	}
		1525
		1526	$SIGPIPE_R
		1527	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1528
		1529	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1146	}	1530	}
1147		1531
1148	$SIGPIPE_R	1532	*signal = $HAVE_ASYNC_INTERRUPT
1149	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1533	? sub {
		1534	my (undef, %arg) = @_;
1150		1535
1151	# not strictly required, as $^F is normally 2, but let's make sure...	1536	# 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}	1537	my $signal = sig2num $arg{signal};
1159	or Carp::croak "required option 'signal' is missing";
1160
1161	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1538	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1539
		1540	$SIG_ASY{$signal} ||= new Async::Interrupt
		1541	cb => sub { undef $SIG_EV{$signal} },
		1542	signal => $signal,
		1543	pipe => [$SIGPIPE_R->filenos],
		1544	pipe_autodrain => 0,
		1545	;
		1546
		1547	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1548	}
		1549	: sub {
		1550	my (undef, %arg) = @_;
		1551
		1552	# pure perl
		1553	my $signal = sig2name $arg{signal};
		1554	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1555
1162	$SIG{$signal} ||= sub {	1556	$SIG{$signal} ||= sub {
1163	local $!;	1557	local $!;
1164	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1558	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1165	undef $SIG_EV{$signal};	1559	undef $SIG_EV{$signal};
		1560	};
		1561
		1562	# can't do signal processing without introducing races in pure perl,
		1563	# so limit the signal latency.
		1564	_sig_add;
		1565
		1566	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1567	}
		1568	;
		1569
		1570	*AnyEvent::Base::signal::DESTROY = sub {
		1571	my ($signal, $cb) = @{$_[0]};
		1572
		1573	_sig_del;
		1574
		1575	delete $SIG_CB{$signal}{$cb};
		1576
		1577	$HAVE_ASYNC_INTERRUPT
		1578	? delete $SIG_ASY{$signal}
		1579	: # delete doesn't work with older perls - they then
		1580	# print weird messages, or just unconditionally exit
		1581	# instead of getting the default action.
		1582	undef $SIG{$signal}
		1583	unless keys %{ $SIG_CB{$signal} };
		1584	};
		1585
		1586	*_signal_exec = sub {
		1587	$HAVE_ASYNC_INTERRUPT
		1588	? $SIGPIPE_R->drain
		1589	: sysread $SIGPIPE_R, (my $dummy), 9;
		1590
		1591	while (%SIG_EV) {
		1592	for (keys %SIG_EV) {
		1593	delete $SIG_EV{$_};
		1594	$_->() for values %{ $SIG_CB{$_} || {} };
		1595	}
		1596	}
		1597	};
1166	};	1598	};
		1599	die if $@;
1167		1600
1168	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1601	&signal
1169	}
1170
1171	sub AnyEvent::Base::signal::DESTROY {
1172	my ($signal, $cb) = @{$_[0]};
1173
1174	delete $SIG_CB{$signal}{$cb};
1175
1176	# delete doesn't work with older perls - they then
1177	# print weird messages, or just unconditionally exit
1178	# instead of getting the default action.
1179	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1180	}	1602	}
1181		1603
1182	# default implementation for ->child	1604	# default implementation for ->child
1183		1605
1184	our %PID_CB;	1606	our %PID_CB;
1185	our $CHLD_W;	1607	our $CHLD_W;
1186	our $CHLD_DELAY_W;	1608	our $CHLD_DELAY_W;
1187	our $WNOHANG;	1609	our $WNOHANG;
1188		1610
1189	sub _sigchld {	1611	# used by many Impl's
1190	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1612	sub _emit_childstatus($$) {
		1613	my (undef, $rpid, $rstatus) = @_;
		1614
		1615	$_->($rpid, $rstatus)
1191	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1616	for values %{ $PID_CB{$rpid} || {} },
1192	(values %{ $PID_CB{0} || {} });	1617	values %{ $PID_CB{0} || {} };
1193	}
1194	}	1618	}
1195		1619
1196	sub child {	1620	sub child {
		1621	eval q{ # poor man's autoloading {}
		1622	*_sigchld = sub {
		1623	my $pid;
		1624
		1625	AnyEvent->_emit_childstatus ($pid, $?)
		1626	while ($pid = waitpid -1, $WNOHANG) > 0;
		1627	};
		1628
		1629	*child = sub {
1197	my (undef, %arg) = @_;	1630	my (undef, %arg) = @_;
1198		1631
1199	defined (my $pid = $arg{pid} + 0)	1632	defined (my $pid = $arg{pid} + 0)
1200	or Carp::croak "required option 'pid' is missing";	1633	or Carp::croak "required option 'pid' is missing";
1201		1634
1202	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1635	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1203		1636
		1637	# WNOHANG is almost cetrainly 1 everywhere
		1638	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1639	? 1
1204	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1640	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1205		1641
1206	unless ($CHLD_W) {	1642	unless ($CHLD_W) {
1207	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1643	$CHLD_W = AE::signal CHLD => \&_sigchld;
1208	# child could be a zombie already, so make at least one round	1644	# child could be a zombie already, so make at least one round
1209	&_sigchld;	1645	&_sigchld;
1210	}	1646	}
1211		1647
1212	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1648	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1213	}	1649	};
1214		1650
1215	sub AnyEvent::Base::child::DESTROY {	1651	*AnyEvent::Base::child::DESTROY = sub {
1216	my ($pid, $cb) = @{$_[0]};	1652	my ($pid, $cb) = @{$_[0]};
1217		1653
1218	delete $PID_CB{$pid}{$cb};	1654	delete $PID_CB{$pid}{$cb};
1219	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1655	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1220		1656
1221	undef $CHLD_W unless keys %PID_CB;	1657	undef $CHLD_W unless keys %PID_CB;
		1658	};
		1659	};
		1660	die if $@;
		1661
		1662	&child
1222	}	1663	}
1223		1664
1224	# idle emulation is done by simply using a timer, regardless	1665	# idle emulation is done by simply using a timer, regardless
1225	# of whether the process is idle or not, and not letting	1666	# of whether the process is idle or not, and not letting
1226	# the callback use more than 50% of the time.	1667	# the callback use more than 50% of the time.
1227	sub idle {	1668	sub idle {
		1669	eval q{ # poor man's autoloading {}
		1670	*idle = sub {
1228	my (undef, %arg) = @_;	1671	my (undef, %arg) = @_;
1229		1672
1230	my ($cb, $w, $rcb) = $arg{cb};	1673	my ($cb, $w, $rcb) = $arg{cb};
1231		1674
1232	$rcb = sub {	1675	$rcb = sub {
1233	if ($cb) {	1676	if ($cb) {
1234	$w = _time;	1677	$w = _time;
1235	&$cb;	1678	&$cb;
1236	$w = _time - $w;	1679	$w = _time - $w;
1237		1680
1238	# never use more then 50% of the time for the idle watcher,	1681	# never use more then 50% of the time for the idle watcher,
1239	# within some limits	1682	# within some limits
1240	$w = 0.0001 if $w < 0.0001;	1683	$w = 0.0001 if $w < 0.0001;
1241	$w = 5 if $w > 5;	1684	$w = 5 if $w > 5;
1242		1685
1243	$w = AnyEvent->timer (after => $w, cb => $rcb);	1686	$w = AE::timer $w, 0, $rcb;
1244	} else {	1687	} else {
1245	# clean up...	1688	# clean up...
1246	undef $w;	1689	undef $w;
1247	undef $rcb;	1690	undef $rcb;
		1691	}
		1692	};
		1693
		1694	$w = AE::timer 0.05, 0, $rcb;
		1695
		1696	bless \\$cb, "AnyEvent::Base::idle"
1248	}	1697	};
		1698
		1699	*AnyEvent::Base::idle::DESTROY = sub {
		1700	undef $${$_[0]};
		1701	};
1249	};	1702	};
		1703	die if $@;
1250		1704
1251	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1705	&idle
1252
1253	bless \\$cb, "AnyEvent::Base::idle"
1254	}
1255
1256	sub AnyEvent::Base::idle::DESTROY {
1257	undef $${$_[0]};
1258	}	1706	}
1259		1707
1260	package AnyEvent::CondVar;	1708	package AnyEvent::CondVar;
1261		1709
1262	our @ISA = AnyEvent::CondVar::Base::;	1710	our @ISA = AnyEvent::CondVar::Base::;
1263		1711
1264	package AnyEvent::CondVar::Base;	1712	package AnyEvent::CondVar::Base;
1265		1713
1266	use overload	1714	#use overload
1267	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1715	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1268	fallback => 1;	1716	# fallback => 1;
		1717
		1718	# save 300+ kilobytes by dirtily hardcoding overloading
		1719	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1720	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1721	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1722	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1723
		1724	our $WAITING;
1269		1725
1270	sub _send {	1726	sub _send {
1271	# nop	1727	# nop
1272	}	1728	}
1273		1729
…		…
1286	sub ready {	1742	sub ready {
1287	$_[0]{_ae_sent}	1743	$_[0]{_ae_sent}
1288	}	1744	}
1289		1745
1290	sub _wait {	1746	sub _wait {
		1747	$WAITING
		1748	and !$_[0]{_ae_sent}
		1749	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1750
		1751	local $WAITING = 1;
1291	AnyEvent->one_event while !$_[0]{_ae_sent};	1752	AnyEvent->one_event while !$_[0]{_ae_sent};
1292	}	1753	}
1293		1754
1294	sub recv {	1755	sub recv {
1295	$_[0]->_wait;	1756	$_[0]->_wait;
…		…
1297	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1758	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1298	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1759	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1299	}	1760	}
1300		1761
1301	sub cb {	1762	sub cb {
1302	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1763	my $cv = shift;
		1764
		1765	@_
		1766	and $cv->{_ae_cb} = shift
		1767	and $cv->{_ae_sent}
		1768	and (delete $cv->{_ae_cb})->($cv);
		1769
1303	$_[0]{_ae_cb}	1770	$cv->{_ae_cb}
1304	}	1771	}
1305		1772
1306	sub begin {	1773	sub begin {
1307	++$_[0]{_ae_counter};	1774	++$_[0]{_ae_counter};
1308	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1775	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1336	so on.	1803	so on.
1337		1804
1338	=head1 ENVIRONMENT VARIABLES	1805	=head1 ENVIRONMENT VARIABLES
1339		1806
1340	The following environment variables are used by this module or its	1807	The following environment variables are used by this module or its
1341	submodules:	1808	submodules.
		1809
		1810	Note that AnyEvent will remove I<all> environment variables starting with
		1811	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1812	enabled.
1342		1813
1343	=over 4	1814	=over 4
1344		1815
1345	=item C<PERL_ANYEVENT_VERBOSE>	1816	=item C<PERL_ANYEVENT_VERBOSE>
1346		1817
…		…
1353	C<PERL_ANYEVENT_MODEL>.	1824	C<PERL_ANYEVENT_MODEL>.
1354		1825
1355	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1826	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1356	model it chooses.	1827	model it chooses.
1357		1828
		1829	When set to C<8> or higher, then AnyEvent will report extra information on
		1830	which optional modules it loads and how it implements certain features.
		1831
1358	=item C<PERL_ANYEVENT_STRICT>	1832	=item C<PERL_ANYEVENT_STRICT>
1359		1833
1360	AnyEvent does not do much argument checking by default, as thorough	1834	AnyEvent does not do much argument checking by default, as thorough
1361	argument checking is very costly. Setting this variable to a true value	1835	argument checking is very costly. Setting this variable to a true value
1362	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1836	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1363	check the arguments passed to most method calls. If it finds any problems	1837	check the arguments passed to most method calls. If it finds any problems,
1364	it will croak.	1838	it will croak.
1365		1839
1366	In other words, enables "strict" mode.	1840	In other words, enables "strict" mode.
1367		1841
1368	Unlike C<use strict>, it is definitely recommended ot keep it off in	1842	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1369	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1843	>>, it is definitely recommended to keep it off in production. Keeping
1370	developing programs can be very useful, however.	1844	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1845	can be very useful, however.
1371		1846
1372	=item C<PERL_ANYEVENT_MODEL>	1847	=item C<PERL_ANYEVENT_MODEL>
1373		1848
1374	This can be used to specify the event model to be used by AnyEvent, before	1849	This can be used to specify the event model to be used by AnyEvent, before
1375	auto detection and -probing kicks in. It must be a string consisting	1850	auto detection and -probing kicks in. It must be a string consisting
…		…
1418		1893
1419	=item C<PERL_ANYEVENT_MAX_FORKS>	1894	=item C<PERL_ANYEVENT_MAX_FORKS>
1420		1895
1421	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1896	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1422	will create in parallel.	1897	will create in parallel.
		1898
		1899	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1900
		1901	The default value for the C<max_outstanding> parameter for the default DNS
		1902	resolver - this is the maximum number of parallel DNS requests that are
		1903	sent to the DNS server.
		1904
		1905	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1906
		1907	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1908	configuration) in the default resolver. When set to the empty string, no
		1909	default config will be used.
		1910
		1911	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1912
		1913	When neither C<ca_file> nor C<ca_path> was specified during
		1914	L<AnyEvent::TLS> context creation, and either of these environment
		1915	variables exist, they will be used to specify CA certificate locations
		1916	instead of a system-dependent default.
		1917
		1918	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1919
		1920	When these are set to C<1>, then the respective modules are not
		1921	loaded. Mostly good for testing AnyEvent itself.
1423		1922
1424	=back	1923	=back
1425		1924
1426	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1925	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1427		1926
…		…
1485	warn "read: $input\n"; # output what has been read	1984	warn "read: $input\n"; # output what has been read
1486	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1985	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1487	},	1986	},
1488	);	1987	);
1489		1988
1490	my $time_watcher; # can only be used once
1491
1492	sub new_timer {
1493	$timer = AnyEvent->timer (after => 1, cb => sub {	1989	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1494	warn "timeout\n"; # print 'timeout' about every second	1990	warn "timeout\n"; # print 'timeout' at most every second
1495	&new_timer; # and restart the time
1496	});	1991	});
1497	}
1498
1499	new_timer; # create first timer
1500		1992
1501	$cv->recv; # wait until user enters /^q/i	1993	$cv->recv; # wait until user enters /^q/i
1502		1994
1503	=head1 REAL-WORLD EXAMPLE	1995	=head1 REAL-WORLD EXAMPLE
1504		1996
…		…
1577		2069
1578	The actual code goes further and collects all errors (C<die>s, exceptions)	2070	The actual code goes further and collects all errors (C<die>s, exceptions)
1579	that occurred during request processing. The C<result> method detects	2071	that occurred during request processing. The C<result> method detects
1580	whether an exception as thrown (it is stored inside the $txn object)	2072	whether an exception as thrown (it is stored inside the $txn object)
1581	and just throws the exception, which means connection errors and other	2073	and just throws the exception, which means connection errors and other
1582	problems get reported tot he code that tries to use the result, not in a	2074	problems get reported to the code that tries to use the result, not in a
1583	random callback.	2075	random callback.
1584		2076
1585	All of this enables the following usage styles:	2077	All of this enables the following usage styles:
1586		2078
1587	1. Blocking:	2079	1. Blocking:
…		…
1635	through AnyEvent. The benchmark creates a lot of timers (with a zero	2127	through AnyEvent. The benchmark creates a lot of timers (with a zero
1636	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2128	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1637	which it is), lets them fire exactly once and destroys them again.	2129	which it is), lets them fire exactly once and destroys them again.
1638		2130
1639	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2131	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1640	distribution.	2132	distribution. It uses the L<AE> interface, which makes a real difference
		2133	for the EV and Perl backends only.
1641		2134
1642	=head3 Explanation of the columns	2135	=head3 Explanation of the columns
1643		2136
1644	I<watcher> is the number of event watchers created/destroyed. Since	2137	I<watcher> is the number of event watchers created/destroyed. Since
1645	different event models feature vastly different performances, each event	2138	different event models feature vastly different performances, each event
…		…
1666	watcher.	2159	watcher.
1667		2160
1668	=head3 Results	2161	=head3 Results
1669		2162
1670	name watchers bytes create invoke destroy comment	2163	name watchers bytes create invoke destroy comment
1671	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2164	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1672	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2165	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1673	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2166	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1674	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2167	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1675	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2168	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1676	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2169	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2170	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2171	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1677	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2172	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1678	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2173	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1679	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2174	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1680	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2175	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1681		2176
1682	=head3 Discussion	2177	=head3 Discussion
1683		2178
1684	The benchmark does I<not> measure scalability of the event loop very	2179	The benchmark does I<not> measure scalability of the event loop very
1685	well. For example, a select-based event loop (such as the pure perl one)	2180	well. For example, a select-based event loop (such as the pure perl one)
…		…
1697	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2192	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1698	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2193	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1699	cycles with POE.	2194	cycles with POE.
1700		2195
1701	C<EV> is the sole leader regarding speed and memory use, which are both	2196	C<EV> is the sole leader regarding speed and memory use, which are both
1702	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2197	maximal/minimal, respectively. When using the L<AE> API there is zero
		2198	overhead (when going through the AnyEvent API create is about 5-6 times
		2199	slower, with other times being equal, so still uses far less memory than
1703	far less memory than any other event loop and is still faster than Event	2200	any other event loop and is still faster than Event natively).
1704	natively.
1705		2201
1706	The pure perl implementation is hit in a few sweet spots (both the	2202	The pure perl implementation is hit in a few sweet spots (both the
1707	constant timeout and the use of a single fd hit optimisations in the perl	2203	constant timeout and the use of a single fd hit optimisations in the perl
1708	interpreter and the backend itself). Nevertheless this shows that it	2204	interpreter and the backend itself). Nevertheless this shows that it
1709	adds very little overhead in itself. Like any select-based backend its	2205	adds very little overhead in itself. Like any select-based backend its
1710	performance becomes really bad with lots of file descriptors (and few of	2206	performance becomes really bad with lots of file descriptors (and few of
1711	them active), of course, but this was not subject of this benchmark.	2207	them active), of course, but this was not subject of this benchmark.
1712		2208
1713	The C<Event> module has a relatively high setup and callback invocation	2209	The C<Event> module has a relatively high setup and callback invocation
1714	cost, but overall scores in on the third place.	2210	cost, but overall scores in on the third place.
		2211
		2212	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2213	when using its pure perl backend.
1715		2214
1716	C<Glib>'s memory usage is quite a bit higher, but it features a	2215	C<Glib>'s memory usage is quite a bit higher, but it features a
1717	faster callback invocation and overall ends up in the same class as	2216	faster callback invocation and overall ends up in the same class as
1718	C<Event>. However, Glib scales extremely badly, doubling the number of	2217	C<Event>. However, Glib scales extremely badly, doubling the number of
1719	watchers increases the processing time by more than a factor of four,	2218	watchers increases the processing time by more than a factor of four,
…		…
1780	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2279	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1781	(1%) are active. This mirrors the activity of large servers with many	2280	(1%) are active. This mirrors the activity of large servers with many
1782	connections, most of which are idle at any one point in time.	2281	connections, most of which are idle at any one point in time.
1783		2282
1784	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2283	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1785	distribution.	2284	distribution. It uses the L<AE> interface, which makes a real difference
		2285	for the EV and Perl backends only.
1786		2286
1787	=head3 Explanation of the columns	2287	=head3 Explanation of the columns
1788		2288
1789	I<sockets> is the number of sockets, and twice the number of "servers" (as	2289	I<sockets> is the number of sockets, and twice the number of "servers" (as
1790	each server has a read and write socket end).	2290	each server has a read and write socket end).
…		…
1797	it to another server. This includes deleting the old timeout and creating	2297	it to another server. This includes deleting the old timeout and creating
1798	a new one that moves the timeout into the future.	2298	a new one that moves the timeout into the future.
1799		2299
1800	=head3 Results	2300	=head3 Results
1801		2301
1802	name sockets create request	2302	name sockets create request
1803	EV 20000 69.01 11.16	2303	EV 20000 62.66 7.99
1804	Perl 20000 73.32 35.87	2304	Perl 20000 68.32 32.64
1805	Event 20000 212.62 257.32	2305	IOAsync 20000 174.06 101.15 epoll
1806	Glib 20000 651.16 1896.30	2306	IOAsync 20000 174.67 610.84 poll
		2307	Event 20000 202.69 242.91
		2308	Glib 20000 557.01 1689.52
1807	POE 20000 349.67 12317.24 uses POE::Loop::Event	2309	POE 20000 341.54 12086.32 uses POE::Loop::Event
1808		2310
1809	=head3 Discussion	2311	=head3 Discussion
1810		2312
1811	This benchmark I<does> measure scalability and overall performance of the	2313	This benchmark I<does> measure scalability and overall performance of the
1812	particular event loop.	2314	particular event loop.
…		…
1814	EV is again fastest. Since it is using epoll on my system, the setup time	2316	EV is again fastest. Since it is using epoll on my system, the setup time
1815	is relatively high, though.	2317	is relatively high, though.
1816		2318
1817	Perl surprisingly comes second. It is much faster than the C-based event	2319	Perl surprisingly comes second. It is much faster than the C-based event
1818	loops Event and Glib.	2320	loops Event and Glib.
		2321
		2322	IO::Async performs very well when using its epoll backend, and still quite
		2323	good compared to Glib when using its pure perl backend.
1819		2324
1820	Event suffers from high setup time as well (look at its code and you will	2325	Event suffers from high setup time as well (look at its code and you will
1821	understand why). Callback invocation also has a high overhead compared to	2326	understand why). Callback invocation also has a high overhead compared to
1822	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2327	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1823	uses select or poll in basically all documented configurations.	2328	uses select or poll in basically all documented configurations.
…		…
1886	=item * C-based event loops perform very well with small number of	2391	=item * C-based event loops perform very well with small number of
1887	watchers, as the management overhead dominates.	2392	watchers, as the management overhead dominates.
1888		2393
1889	=back	2394	=back
1890		2395
		2396	=head2 THE IO::Lambda BENCHMARK
		2397
		2398	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2399	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2400	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2401	shouldn't come as a surprise to anybody). As such, the benchmark is
		2402	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2403	very optimal. But how would AnyEvent compare when used without the extra
		2404	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2405
		2406	The benchmark itself creates an echo-server, and then, for 500 times,
		2407	connects to the echo server, sends a line, waits for the reply, and then
		2408	creates the next connection. This is a rather bad benchmark, as it doesn't
		2409	test the efficiency of the framework or much non-blocking I/O, but it is a
		2410	benchmark nevertheless.
		2411
		2412	name runtime
		2413	Lambda/select 0.330 sec
		2414	+ optimized 0.122 sec
		2415	Lambda/AnyEvent 0.327 sec
		2416	+ optimized 0.138 sec
		2417	Raw sockets/select 0.077 sec
		2418	POE/select, components 0.662 sec
		2419	POE/select, raw sockets 0.226 sec
		2420	POE/select, optimized 0.404 sec
		2421
		2422	AnyEvent/select/nb 0.085 sec
		2423	AnyEvent/EV/nb 0.068 sec
		2424	+state machine 0.134 sec
		2425
		2426	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2427	benchmarks actually make blocking connects and use 100% blocking I/O,
		2428	defeating the purpose of an event-based solution. All of the newly
		2429	written AnyEvent benchmarks use 100% non-blocking connects (using
		2430	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2431	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2432	generally require a lot more bookkeeping and event handling than blocking
		2433	connects (which involve a single syscall only).
		2434
		2435	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2436	offers similar expressive power as POE and IO::Lambda, using conventional
		2437	Perl syntax. This means that both the echo server and the client are 100%
		2438	non-blocking, further placing it at a disadvantage.
		2439
		2440	As you can see, the AnyEvent + EV combination even beats the
		2441	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2442	backend easily beats IO::Lambda and POE.
		2443
		2444	And even the 100% non-blocking version written using the high-level (and
		2445	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2446	higher level ("unoptimised") abstractions by a large margin, even though
		2447	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
		2448
		2449	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2450	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2451	part of the IO::Lambda distribution and were used without any changes.
		2452
1891		2453
1892	=head1 SIGNALS	2454	=head1 SIGNALS
1893		2455
1894	AnyEvent currently installs handlers for these signals:	2456	AnyEvent currently installs handlers for these signals:
1895		2457
…		…
1898	=item SIGCHLD	2460	=item SIGCHLD
1899		2461
1900	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2462	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1901	emulation for event loops that do not support them natively. Also, some	2463	emulation for event loops that do not support them natively. Also, some
1902	event loops install a similar handler.	2464	event loops install a similar handler.
		2465
		2466	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2467	AnyEvent will reset it to default, to avoid losing child exit statuses.
1903		2468
1904	=item SIGPIPE	2469	=item SIGPIPE
1905		2470
1906	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2471	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1907	when AnyEvent gets loaded.	2472	when AnyEvent gets loaded.
…		…
1919		2484
1920	=back	2485	=back
1921		2486
1922	=cut	2487	=cut
1923		2488
		2489	undef $SIG{CHLD}
		2490	if $SIG{CHLD} eq 'IGNORE';
		2491
1924	$SIG{PIPE} = sub { }	2492	$SIG{PIPE} = sub { }
1925	unless defined $SIG{PIPE};	2493	unless defined $SIG{PIPE};
1926		2494
		2495	=head1 RECOMMENDED/OPTIONAL MODULES
		2496
		2497	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2498	it's built-in modules) are required to use it.
		2499
		2500	That does not mean that AnyEvent won't take advantage of some additional
		2501	modules if they are installed.
		2502
		2503	This section explains which additional modules will be used, and how they
		2504	affect AnyEvent's operation.
		2505
		2506	=over 4
		2507
		2508	=item L<Async::Interrupt>
		2509
		2510	This slightly arcane module is used to implement fast signal handling: To
		2511	my knowledge, there is no way to do completely race-free and quick
		2512	signal handling in pure perl. To ensure that signals still get
		2513	delivered, AnyEvent will start an interval timer to wake up perl (and
		2514	catch the signals) with some delay (default is 10 seconds, look for
		2515	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2516
		2517	If this module is available, then it will be used to implement signal
		2518	catching, which means that signals will not be delayed, and the event loop
		2519	will not be interrupted regularly, which is more efficient (and good for
		2520	battery life on laptops).
		2521
		2522	This affects not just the pure-perl event loop, but also other event loops
		2523	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2524
		2525	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2526	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2527	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2528	does nothing for those backends.
		2529
		2530	=item L<EV>
		2531
		2532	This module isn't really "optional", as it is simply one of the backend
		2533	event loops that AnyEvent can use. However, it is simply the best event
		2534	loop available in terms of features, speed and stability: It supports
		2535	the AnyEvent API optimally, implements all the watcher types in XS, does
		2536	automatic timer adjustments even when no monotonic clock is available,
		2537	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2538	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2539	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2540
		2541	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2542	then this module will do nothing for you.
		2543
		2544	=item L<Guard>
		2545
		2546	The guard module, when used, will be used to implement
		2547	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2548	lot less memory), but otherwise doesn't affect guard operation much. It is
		2549	purely used for performance.
		2550
		2551	=item L<JSON> and L<JSON::XS>
		2552
		2553	One of these modules is required when you want to read or write JSON data
		2554	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2555	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2556
		2557	=item L<Net::SSLeay>
		2558
		2559	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2560	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2561	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2562
		2563	=item L<Time::HiRes>
		2564
		2565	This module is part of perl since release 5.008. It will be used when the
		2566	chosen event library does not come with a timing source on it's own. The
		2567	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2568	try to use a monotonic clock for timing stability.
		2569
		2570	=back
		2571
1927		2572
1928	=head1 FORK	2573	=head1 FORK
1929		2574
1930	Most event libraries are not fork-safe. The ones who are usually are	2575	Most event libraries are not fork-safe. The ones who are usually are
1931	because they rely on inefficient but fork-safe C<select> or C<poll>	2576	because they rely on inefficient but fork-safe C<select> or C<poll> calls
1932	calls. Only L<EV> is fully fork-aware.	2577	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2578	are usually badly thought-out hacks that are incompatible with fork in
		2579	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2580	continue event-processing in both parent and child (or both, if you know
		2581	what you are doing).
		2582
		2583	This means that, in general, you cannot fork and do event processing in
		2584	the child if the event library was initialised before the fork (which
		2585	usually happens when the first AnyEvent watcher is created, or the library
		2586	is loaded).
1933		2587
1934	If you have to fork, you must either do so I<before> creating your first	2588	If you have to fork, you must either do so I<before> creating your first
1935	watcher OR you must not use AnyEvent at all in the child.	2589	watcher OR you must not use AnyEvent at all in the child OR you must do
		2590	something completely out of the scope of AnyEvent.
		2591
		2592	The problem of doing event processing in the parent I<and> the child
		2593	is much more complicated: even for backends that I<are> fork-aware or
		2594	fork-safe, their behaviour is not usually what you want: fork clones all
		2595	watchers, that means all timers, I/O watchers etc. are active in both
		2596	parent and child, which is almost never what you want. USing C<exec>
		2597	to start worker children from some kind of manage rprocess is usually
		2598	preferred, because it is much easier and cleaner, at the expense of having
		2599	to have another binary.
1936		2600
1937		2601
1938	=head1 SECURITY CONSIDERATIONS	2602	=head1 SECURITY CONSIDERATIONS
1939		2603
1940	AnyEvent can be forced to load any event model via	2604	AnyEvent can be forced to load any event model via
…		…
1952	use AnyEvent;	2616	use AnyEvent;
1953		2617
1954	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2618	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1955	be used to probe what backend is used and gain other information (which is	2619	be used to probe what backend is used and gain other information (which is
1956	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2620	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1957	$ENV{PERL_ANYEGENT_STRICT}.	2621	$ENV{PERL_ANYEVENT_STRICT}.
		2622
		2623	Note that AnyEvent will remove I<all> environment variables starting with
		2624	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2625	enabled.
1958		2626
1959		2627
1960	=head1 BUGS	2628	=head1 BUGS
1961		2629
1962	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2630	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
…		…
1974	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2642	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1975		2643
1976	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2644	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1977	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2645	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1978	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2646	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1979	L<AnyEvent::Impl::POE>.	2647	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1980		2648
1981	Non-blocking file handles, sockets, TCP clients and	2649	Non-blocking file handles, sockets, TCP clients and
1982	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2650	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1983		2651
1984	Asynchronous DNS: L<AnyEvent::DNS>.	2652	Asynchronous DNS: L<AnyEvent::DNS>.
1985		2653
1986	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2654	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2655	L<Coro::Event>,
1987		2656
1988	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2657	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2658	L<AnyEvent::HTTP>.
1989		2659
1990		2660
1991	=head1 AUTHOR	2661	=head1 AUTHOR
1992		2662
1993	Marc Lehmann <schmorp@schmorp.de>	2663	Marc Lehmann <schmorp@schmorp.de>

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