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Revision 1.217 by root, Tue Jun 23 23:37:32 2009 UTC vs.
Revision 1.318 by root, Wed Mar 24 23:28:06 2010 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
6	event loops.	6	and POE are various supported event loops/environments.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
		12	# if you prefer function calls, look at the L<AE> manpage for
		13	# an alternative API.
		14
12	# file descriptor readable	15	# file handle or descriptor readable
13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14		17
15	# one-shot or repeating timers	18	# one-shot or repeating timers
16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
…		…
40	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
41		44
42	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
43	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
		48
		49	=head1 SUPPORT
		50
		51	There is a mailinglist for discussing all things AnyEvent, and an IRC
		52	channel, too.
		53
		54	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		55	Repository>, at L<http://anyevent.schmorp.de>, for more info.
45		56
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	57	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		58
48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	59	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49	nowadays. So what is different about AnyEvent?	60	nowadays. So what is different about AnyEvent?
…		…
173	my variables are only visible after the statement in which they are	184	my variables are only visible after the statement in which they are
174	declared.	185	declared.
175		186
176	=head2 I/O WATCHERS	187	=head2 I/O WATCHERS
177		188
		189	$w = AnyEvent->io (
		190	fh => <filehandle_or_fileno>,
		191	poll => <"r" or "w">,
		192	cb => <callback>,
		193	);
		194
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	195	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	196	with the following mandatory key-value pairs as arguments:
180		197
181	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch	198	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
182	for events (AnyEvent might or might not keep a reference to this file	199	for events (AnyEvent might or might not keep a reference to this file
183	handle). Note that only file handles pointing to things for which	200	handle). Note that only file handles pointing to things for which
184	non-blocking operation makes sense are allowed. This includes sockets,	201	non-blocking operation makes sense are allowed. This includes sockets,
185	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
186	or block devices.	203	or block devices.
…		…
211	undef $w;	228	undef $w;
212	});	229	});
213		230
214	=head2 TIME WATCHERS	231	=head2 TIME WATCHERS
215		232
		233	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		234
		235	$w = AnyEvent->timer (
		236	after => <fractional_seconds>,
		237	interval => <fractional_seconds>,
		238	cb => <callback>,
		239	);
		240
216	You can create a time watcher by calling the C<< AnyEvent->timer >>	241	You can create a time watcher by calling the C<< AnyEvent->timer >>
217	method with the following mandatory arguments:	242	method with the following mandatory arguments:
218		243
219	C<after> specifies after how many seconds (fractional values are	244	C<after> specifies after how many seconds (fractional values are
220	supported) the callback should be invoked. C<cb> is the callback to invoke	245	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
341	might affect timers and time-outs.	366	might affect timers and time-outs.
342		367
343	When this is the case, you can call this method, which will update the	368	When this is the case, you can call this method, which will update the
344	event loop's idea of "current time".	369	event loop's idea of "current time".
345		370
		371	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		372	when mod_perl executes the script, then the event loop will have the wrong
		373	idea about the "current time" (being potentially far in the past, when the
		374	script ran the last time). In that case you should arrange a call to C<<
		375	AnyEvent->now_update >> each time the web server process wakes up again
		376	(e.g. at the start of your script, or in a handler).
		377
346	Note that updating the time I<might> cause some events to be handled.	378	Note that updating the time I<might> cause some events to be handled.
347		379
348	=back	380	=back
349		381
350	=head2 SIGNAL WATCHERS	382	=head2 SIGNAL WATCHERS
		383
		384	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351		385
352	You can watch for signals using a signal watcher, C<signal> is the signal	386	You can watch for signals using a signal watcher, C<signal> is the signal
353	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	387	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354	callback to be invoked whenever a signal occurs.	388	callback to be invoked whenever a signal occurs.
355		389
…		…
361	invocation, and callback invocation will be synchronous. Synchronous means	395	invocation, and callback invocation will be synchronous. Synchronous means
362	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,
363	but it is guaranteed not to interrupt any other callbacks.	397	but it is guaranteed not to interrupt any other callbacks.
364		398
365	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
366	between multiple watchers.	400	between multiple watchers, and AnyEvent will ensure that signals will not
		401	interrupt your program at bad times.
367		402
368	This watcher might use C<%SIG>, so programs overwriting those signals	403	This watcher might use C<%SIG> (depending on the event loop used),
369	directly will likely not work correctly.	404	so programs overwriting those signals directly will likely not work
		405	correctly.
370		406
371	Example: exit on SIGINT	407	Example: exit on SIGINT
372		408
373	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	409	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
374		410
		411	=head3 Restart Behaviour
		412
		413	While restart behaviour is up to the event loop implementation, most will
		414	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		415	pure perl implementation).
		416
		417	=head3 Safe/Unsafe Signals
		418
		419	Perl signals can be either "safe" (synchronous to opcode handling) or
		420	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		421	latter might corrupt your memory.
		422
		423	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		424	i.e. they will not interrupt your running perl program but will only be
		425	called as part of the normal event handling (just like timer, I/O etc.
		426	callbacks, too).
		427
		428	=head3 Signal Races, Delays and Workarounds
		429
		430	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		431	callbacks to signals in a generic way, which is a pity, as you cannot
		432	do race-free signal handling in perl, requiring C libraries for
		433	this. AnyEvent will try to do it's best, which means in some cases,
		434	signals will be delayed. The maximum time a signal might be delayed is
		435	specified in C<$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
375	=head2 CHILD PROCESS WATCHERS	448	=head2 CHILD PROCESS WATCHERS
376		449
		450	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		451
377	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.
378		453
379	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,
380	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
381	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
382	any trace events (stopped/continued).	457	finished and an exit status is available, not on any trace events
		458	(stopped/continued).
383		459
384	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
385	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
386	callback arguments.	462	callback arguments.
387		463
…		…
392		468
393	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
394	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
395	have exited already (and no SIGCHLD will be sent anymore).	471	have exited already (and no SIGCHLD will be sent anymore).
396		472
397	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
398	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
399	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.
400		479
401	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
402	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
403	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.
404		488
405	Example: fork a process and wait for it	489	Example: fork a process and wait for it
406		490
407	my $done = AnyEvent->condvar;	491	my $done = AnyEvent->condvar;
408		492
…		…
420	# do something else, then wait for process exit	504	# do something else, then wait for process exit
421	$done->recv;	505	$done->recv;
422		506
423	=head2 IDLE WATCHERS	507	=head2 IDLE WATCHERS
424		508
425	Sometimes there is a need to do something, but it is not so important	509	$w = AnyEvent->idle (cb => <callback>);
426	to do it instantly, but only when there is nothing better to do. This
427	"nothing better to do" is usually defined to be "no other events need
428	attention by the event loop".
429		510
430	Idle watchers ideally get invoked when the event loop has nothing	511	Repeatedly invoke the callback after the process becomes idle, until
431	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.
432	events. Instead of blocking, the idle watcher is invoked.
433		513
434	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
435	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
436	will simply call the callback "from time to time".	525	will simply call the callback "from time to time".
437		526
438	Example: read lines from STDIN, but only process them when the	527	Example: read lines from STDIN, but only process them when the
439	program is otherwise idle:	528	program is otherwise idle:
…		…
455	});	544	});
456	});	545	});
457		546
458	=head2 CONDITION VARIABLES	547	=head2 CONDITION VARIABLES
459		548
		549	$cv = AnyEvent->condvar;
		550
		551	$cv->send (<list>);
		552	my @res = $cv->recv;
		553
460	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
461	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
462	will actively watch for new events and call your callbacks.	556	will actively watch for new events and call your callbacks.
463		557
464	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
465	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).
466		560
467	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
468	because they represent a condition that must become true.	562	because they represent a condition that must become true.
469		563
		564	Now is probably a good time to look at the examples further below.
		565
470	Condition variables can be created by calling the C<< AnyEvent->condvar	566	Condition variables can be created by calling the C<< AnyEvent->condvar
471	>> method, usually without arguments. The only argument pair allowed is	567	>> method, usually without arguments. The only argument pair allowed is
472
473	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
474	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
475	the results).	570	the results).
476		571
477	After creation, the condition variable is "false" until it becomes "true"	572	After creation, the condition variable is "false" until it becomes "true"
…		…
482	Condition variables are similar to callbacks, except that you can	577	Condition variables are similar to callbacks, except that you can
483	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
484	in time where multiple outstanding events have been processed. And yet	579	in time where multiple outstanding events have been processed. And yet
485	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
486	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
487	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.
488		584
489	Condition variables are very useful to signal that something has finished,	585	Condition variables are very useful to signal that something has finished,
490	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,
491	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
492	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
…		…
526	after => 1,	622	after => 1,
527	cb => sub { $result_ready->send },	623	cb => sub { $result_ready->send },
528	);	624	);
529		625
530	# this "blocks" (while handling events) till the callback	626	# this "blocks" (while handling events) till the callback
531	# calls send	627	# calls ->send
532	$result_ready->recv;	628	$result_ready->recv;
533		629
534	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
535	condition variables are also code references.	631	variables are also callable directly.
536		632
537	my $done = AnyEvent->condvar;	633	my $done = AnyEvent->condvar;
538	my $delay = AnyEvent->timer (after => 5, cb => $done);	634	my $delay = AnyEvent->timer (after => 5, cb => $done);
539	$done->recv;	635	$done->recv;
540		636
…		…
546		642
547	...	643	...
548		644
549	my @info = $couchdb->info->recv;	645	my @info = $couchdb->info->recv;
550		646
551	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
552	results are available:	648	results are available:
553		649
554	$couchdb->info->cb (sub {	650	$couchdb->info->cb (sub {
555	my @info = $_[0]->recv;	651	my @info = $_[0]->recv;
556	});	652	});
…		…
574	immediately from within send.	670	immediately from within send.
575		671
576	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
577	future C<< ->recv >> calls.	673	future C<< ->recv >> calls.
578		674
579	Condition variables are overloaded so one can call them directly	675	Condition variables are overloaded so one can call them directly (as if
580	(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
581	C<send>. Note, however, that many C-based event loops do not handle	677	C<send>.
582	overloading, so as tempting as it may be, passing a condition variable
583	instead of a callback does not work. Both the pure perl and EV loops
584	support overloading, however, as well as all functions that use perl to
585	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
586	example).
587		678
588	=item $cv->croak ($error)	679	=item $cv->croak ($error)
589		680
590	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
591	C<Carp::croak> with the given error message/object/scalar.	682	C<Carp::croak> with the given error message/object/scalar.
592		683
593	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
594	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.
595		690
596	=item $cv->begin ([group callback])	691	=item $cv->begin ([group callback])
597		692
598	=item $cv->end	693	=item $cv->end
599
600	These two methods are EXPERIMENTAL and MIGHT CHANGE.
601		694
602	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
603	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
604	to use a condition variable for the whole process.	697	to use a condition variable for the whole process.
605		698
606	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
607	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
608	>>, 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
609	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
610	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.
611		705
612	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:
613		713
614	my $cv = AnyEvent->condvar;	714	my $cv = AnyEvent->condvar;
615		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
616	my %result;	740	my %result;
617	$cv->begin (sub { $cv->send (\%result) });	741	$cv->begin (sub { shift->send (\%result) });
618		742
619	for my $host (@list_of_hosts) {	743	for my $host (@list_of_hosts) {
620	$cv->begin;	744	$cv->begin;
621	ping_host_then_call_callback $host, sub {	745	ping_host_then_call_callback $host, sub {
622	$result{$host} = ...;	746	$result{$host} = ...;
…		…
637	loop, which serves two important purposes: first, it sets the callback	761	loop, which serves two important purposes: first, it sets the callback
638	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
639	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
640	doesn't execute once).	764	doesn't execute once).
641		765
642	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
643	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
644	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
645	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>.
646		771
647	=back	772	=back
648		773
649	=head3 METHODS FOR CONSUMERS	774	=head3 METHODS FOR CONSUMERS
650		775
…		…
666	function will call C<croak>.	791	function will call C<croak>.
667		792
668	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,
669	in scalar context only the first one will be returned.	794	in scalar context only the first one will be returned.
670		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
671	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
672	(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
673	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
674	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
675	condition variables with some kind of request results and supporting	807	condition variables with some kind of request results and supporting
676	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,
677	while still supporting blocking waits if the caller so desires).	809	while still supporting blocking waits if the caller so desires).
678		810
679	Another reason I<never> to C<< ->recv >> in a module is that you cannot
680	sensibly have two C<< ->recv >>'s in parallel, as that would require
681	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
682	can supply.
683
684	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
685	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
686	versions and also integrates coroutines into AnyEvent, making blocking
687	C<< ->recv >> calls perfectly safe as long as they are done from another
688	coroutine (one that doesn't run the event loop).
689
690	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
691	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
692	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
693	waits otherwise.	814	waits otherwise.
694		815
…		…
700	=item $cb = $cv->cb ($cb->($cv))	821	=item $cb = $cv->cb ($cb->($cv))
701		822
702	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
703	replaces it before doing so.	824	replaces it before doing so.
704		825
705	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)
706	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
707	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>
708	is guaranteed not to block.	829	inside the callback or at any later time is guaranteed not to block.
709		830
710	=back	831	=back
711		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
712	=head1 GLOBAL VARIABLES AND FUNCTIONS	901	=head1 GLOBAL VARIABLES AND FUNCTIONS
713		902
		903	These are not normally required to use AnyEvent, but can be useful to
		904	write AnyEvent extension modules.
		905
714	=over 4	906	=over 4
715		907
716	=item $AnyEvent::MODEL	908	=item $AnyEvent::MODEL
717		909
718	Contains C<undef> until the first watcher is being created. Then it	910	Contains C<undef> until the first watcher is being created, before the
		911	backend has been autodetected.
		912
719	contains the event model that is being used, which is the name of the	913	Afterwards it contains the event model that is being used, which is the
720	Perl class implementing the model. This class is usually one of the	914	name of the Perl class implementing the model. This class is usually one
721	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	915	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
722	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	916	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
723		917	will be C<urxvt::anyevent>).
724	The known classes so far are:
725
726	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
727	AnyEvent::Impl::Event based on Event, second best choice.
728	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
729	AnyEvent::Impl::Glib based on Glib, third-best choice.
730	AnyEvent::Impl::Tk based on Tk, very bad choice.
731	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
732	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
733	AnyEvent::Impl::POE based on POE, not generic enough for full support.
734
735	There is no support for WxWidgets, as WxWidgets has no support for
736	watching file handles. However, you can use WxWidgets through the
737	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
738	second, which was considered to be too horrible to even consider for
739	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
740	it's adaptor.
741
742	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
743	autodetecting them.
744		918
745	=item AnyEvent::detect	919	=item AnyEvent::detect
746		920
747	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	921	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
748	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
749	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
750	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>.
751		928
752	=item $guard = AnyEvent::post_detect { BLOCK }	929	=item $guard = AnyEvent::post_detect { BLOCK }
753		930
754	Arranges for the code block to be executed as soon as the event model is	931	Arranges for the code block to be executed as soon as the event model is
755	autodetected (or immediately if this has already happened).	932	autodetected (or immediately if this has already happened).
756		933
		934	The block will be executed I<after> the actual backend has been detected
		935	(C<$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
757	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
758	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
759	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 ||= $guard;
760		965
761	=item @AnyEvent::post_detect	966	=item @AnyEvent::post_detect
762		967
763	If there are any code references in this array (you can C<push> to it	968	If there are any code references in this array (you can C<push> to it
764	before or after loading AnyEvent), then they will called directly after	969	before or after loading AnyEvent), then they will called directly after
765	the event loop has been chosen.	970	the event loop has been chosen.
766		971
767	You should check C<$AnyEvent::MODEL> before adding to this array, though:	972	You should check C<$AnyEvent::MODEL> before adding to this array, though:
768	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
769	and the array will be ignored.	974	array will be ignored.
770		975
771	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	}
772		996
773	=back	997	=back
774		998
775	=head1 WHAT TO DO IN A MODULE	999	=head1 WHAT TO DO IN A MODULE
776		1000
…		…
831		1055
832		1056
833	=head1 OTHER MODULES	1057	=head1 OTHER MODULES
834		1058
835	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
836	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
837	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
838	available via CPAN.	1062	come with AnyEvent, most are available via CPAN.
839		1063
840	=over 4	1064	=over 4
841		1065
842	=item L<AnyEvent::Util>	1066	=item L<AnyEvent::Util>
843		1067
…		…
852		1076
853	=item L<AnyEvent::Handle>	1077	=item L<AnyEvent::Handle>
854		1078
855	Provide read and write buffers, manages watchers for reads and writes,	1079	Provide read and write buffers, manages watchers for reads and writes,
856	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
857	non-blocking SSL/TLS.	1081	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
858		1082
859	=item L<AnyEvent::DNS>	1083	=item L<AnyEvent::DNS>
860		1084
861	Provides rich asynchronous DNS resolver capabilities.	1085	Provides rich asynchronous DNS resolver capabilities.
862		1086
…		…
890		1114
891	=item L<AnyEvent::GPSD>	1115	=item L<AnyEvent::GPSD>
892		1116
893	A non-blocking interface to gpsd, a daemon delivering GPS information.	1117	A non-blocking interface to gpsd, a daemon delivering GPS information.
894		1118
		1119	=item L<AnyEvent::IRC>
		1120
		1121	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1122
		1123	=item L<AnyEvent::XMPP>
		1124
		1125	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1126	Net::XMPP2>.
		1127
895	=item L<AnyEvent::IGS>	1128	=item L<AnyEvent::IGS>
896		1129
897	A non-blocking interface to the Internet Go Server protocol (used by	1130	A non-blocking interface to the Internet Go Server protocol (used by
898	L<App::IGS>).	1131	L<App::IGS>).
899		1132
900	=item L<AnyEvent::IRC>
901
902	AnyEvent based IRC client module family (replacing the older Net::IRC3).
903
904	=item L<Net::XMPP2>
905
906	AnyEvent based XMPP (Jabber protocol) module family.
907
908	=item L<Net::FCP>	1133	=item L<Net::FCP>
909		1134
910	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1135	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
911	of AnyEvent.	1136	of AnyEvent.
912		1137
…		…
916		1141
917	=item L<Coro>	1142	=item L<Coro>
918		1143
919	Has special support for AnyEvent via L<Coro::AnyEvent>.	1144	Has special support for AnyEvent via L<Coro::AnyEvent>.
920		1145
921	=item L<IO::Lambda>
922
923	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
924
925	=back	1146	=back
926		1147
927	=cut	1148	=cut
928		1149
929	package AnyEvent;	1150	package AnyEvent;
930		1151
931	no warnings;	1152	# basically a tuned-down version of common::sense
932	use strict qw(vars subs);	1153	sub common_sense {
		1154	# from common:.sense 1.0
		1155	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
		1156	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1157	$^H |= 0x00000600;
		1158	}
933		1159
		1160	BEGIN { AnyEvent::common_sense }
		1161
934	use Carp;	1162	use Carp ();
935		1163
936	our $VERSION = 4.412;	1164	our $VERSION = '5.251';
937	our $MODEL;	1165	our $MODEL;
938		1166
939	our $AUTOLOAD;	1167	our $AUTOLOAD;
940	our @ISA;	1168	our @ISA;
941		1169
942	our @REGISTRY;	1170	our @REGISTRY;
943		1171
944	our $WIN32;	1172	our $VERBOSE;
945		1173
946	BEGIN {	1174	BEGIN {
947	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1175	require "AnyEvent/constants.pl";
		1176
948	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1177	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
949		1178
950	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1179	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
951	if ${^TAINT};	1180	if ${^TAINT};
952	}
953		1181
954	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1182	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1183
		1184	}
		1185
		1186	our $MAX_SIGNAL_LATENCY = 10;
955		1187
956	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1188	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
957		1189
958	{	1190	{
959	my $idx;	1191	my $idx;
…		…
961	for reverse split /\s*,\s*/,	1193	for reverse split /\s*,\s*/,
962	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1194	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
963	}	1195	}
964		1196
965	my @models = (	1197	my @models = (
966	[EV:: => AnyEvent::Impl::EV::],	1198	[EV:: => AnyEvent::Impl::EV:: , 1],
967	[Event:: => AnyEvent::Impl::Event::],
968	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1199	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
969	# everything below here will not be autoprobed	1200	# everything below here will not (normally) be autoprobed
970	# as the pureperl backend should work everywhere	1201	# as the pureperl backend should work everywhere
971	# and is usually faster	1202	# and is usually faster
		1203	[Event:: => AnyEvent::Impl::Event::, 1],
		1204	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1205	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1206	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
972	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1207	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
973	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
974	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
975	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1208	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
976	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1209	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
977	[Wx:: => AnyEvent::Impl::POE::],	1210	[Wx:: => AnyEvent::Impl::POE::],
978	[Prima:: => AnyEvent::Impl::POE::],	1211	[Prima:: => AnyEvent::Impl::POE::],
		1212	# IO::Async is just too broken - we would need workarounds for its
		1213	# byzantine signal and broken child handling, among others.
		1214	# IO::Async is rather hard to detect, as it doesn't have any
		1215	# obvious default class.
		1216	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1217	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1218	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1219	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
979	);	1220	);
980		1221
981	our %method = map +($_ => 1),	1222	our %method = map +($_ => 1),
982	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1223	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
983		1224
984	our @post_detect;	1225	our @post_detect;
985		1226
986	sub post_detect(&) {	1227	sub post_detect(&) {
987	my ($cb) = @_;	1228	my ($cb) = @_;
988		1229
989	if ($MODEL) {
990	$cb->();
991
992	1
993	} else {
994	push @post_detect, $cb;	1230	push @post_detect, $cb;
995		1231
996	defined wantarray	1232	defined wantarray
997	? bless \$cb, "AnyEvent::Util::postdetect"	1233	? bless \$cb, "AnyEvent::Util::postdetect"
998	: ()	1234	: ()
999	}
1000	}	1235	}
1001		1236
1002	sub AnyEvent::Util::postdetect::DESTROY {	1237	sub AnyEvent::Util::postdetect::DESTROY {
1003	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1238	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1004	}	1239	}
1005		1240
1006	sub detect() {	1241	sub detect() {
		1242	# free some memory
		1243	*detect = sub () { $MODEL };
		1244
		1245	local $!; # for good measure
		1246	local $SIG{__DIE__};
		1247
		1248	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1249	my $model = "AnyEvent::Impl::$1";
		1250	if (eval "require $model") {
		1251	$MODEL = $model;
		1252	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1253	} else {
		1254	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1255	}
		1256	}
		1257
		1258	# check for already loaded models
1007	unless ($MODEL) {	1259	unless ($MODEL) {
1008	no strict 'refs';	1260	for (@REGISTRY, @models) {
1009	local $SIG{__DIE__};	1261	my ($package, $model) = @$_;
1010		1262	if (${"$package\::VERSION"} > 0) {
1011	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1012	my $model = "AnyEvent::Impl::$1";
1013	if (eval "require $model") {	1263	if (eval "require $model") {
1014	$MODEL = $model;	1264	$MODEL = $model;
1015	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1265	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1016	} else {	1266	last;
1017	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1267	}
1018	}	1268	}
1019	}	1269	}
1020		1270
1021	# check for already loaded models
1022	unless ($MODEL) {	1271	unless ($MODEL) {
		1272	# try to autoload a model
1023	for (@REGISTRY, @models) {	1273	for (@REGISTRY, @models) {
1024	my ($package, $model) = @$_;	1274	my ($package, $model, $autoload) = @$_;
		1275	if (
		1276	$autoload
		1277	and eval "require $package"
1025	if (${"$package\::VERSION"} > 0) {	1278	and ${"$package\::VERSION"} > 0
1026	if (eval "require $model") {	1279	and eval "require $model"
		1280	) {
1027	$MODEL = $model;	1281	$MODEL = $model;
1028	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1282	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1029	last;	1283	last;
1030	}
1031	}	1284	}
1032	}	1285	}
1033		1286
1034	unless ($MODEL) {
1035	# try to load a model
1036
1037	for (@REGISTRY, @models) {
1038	my ($package, $model) = @$_;
1039	if (eval "require $package"
1040	and ${"$package\::VERSION"} > 0
1041	and eval "require $model") {
1042	$MODEL = $model;
1043	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1044	last;
1045	}
1046	}
1047
1048	$MODEL	1287	$MODEL
1049	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1288	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
1050	}
1051	}	1289	}
1052
1053	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1054
1055	unshift @ISA, $MODEL;
1056
1057	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1058
1059	(shift @post_detect)->() while @post_detect;
1060	}	1290	}
		1291
		1292	@models = (); # free probe data
		1293
		1294	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1295	unshift @ISA, $MODEL;
		1296
		1297	# now nuke some methods that are overriden by the backend.
		1298	# SUPER is not allowed.
		1299	for (qw(time signal child idle)) {
		1300	undef &{"AnyEvent::Base::$_"}
		1301	if defined &{"$MODEL\::$_"};
		1302	}
		1303
		1304	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1305
		1306	(shift @post_detect)->() while @post_detect;
		1307
		1308	*post_detect = sub(&) {
		1309	shift->();
		1310
		1311	undef
		1312	};
1061		1313
1062	$MODEL	1314	$MODEL
1063	}	1315	}
1064		1316
1065	sub AUTOLOAD {	1317	sub AUTOLOAD {
1066	(my $func = $AUTOLOAD) =~ s/.*://;	1318	(my $func = $AUTOLOAD) =~ s/.*://;
1067		1319
1068	$method{$func}	1320	$method{$func}
1069	or croak "$func: not a valid method for AnyEvent objects";	1321	or Carp::croak "$func: not a valid AnyEvent class method";
1070		1322
1071	detect unless $MODEL;	1323	detect;
1072		1324
1073	my $class = shift;	1325	my $class = shift;
1074	$class->$func (@_);	1326	$class->$func (@_);
1075	}	1327	}
1076		1328
1077	# utility function to dup a filehandle. this is used by many backends	1329	# utility function to dup a filehandle. this is used by many backends
1078	# to support binding more than one watcher per filehandle (they usually	1330	# to support binding more than one watcher per filehandle (they usually
1079	# allow only one watcher per fd, so we dup it to get a different one).	1331	# allow only one watcher per fd, so we dup it to get a different one).
1080	sub _dupfh($$$$) {	1332	sub _dupfh($$;$$) {
1081	my ($poll, $fh, $r, $w) = @_;	1333	my ($poll, $fh, $r, $w) = @_;
1082		1334
1083	# cygwin requires the fh mode to be matching, unix doesn't	1335	# cygwin requires the fh mode to be matching, unix doesn't
1084	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1336	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1085	: $poll eq "w" ? ($w, ">")
1086	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1087		1337
1088	open my $fh2, "$mode&" . fileno $fh	1338	open my $fh2, $mode, $fh
1089	or die "cannot dup() filehandle: $!,";	1339	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1090		1340
1091	# we assume CLOEXEC is already set by perl in all important cases	1341	# we assume CLOEXEC is already set by perl in all important cases
1092		1342
1093	($fh2, $rw)	1343	($fh2, $rw)
1094	}	1344	}
1095		1345
		1346	=head1 SIMPLIFIED AE API
		1347
		1348	Starting with version 5.0, AnyEvent officially supports a second, much
		1349	simpler, API that is designed to reduce the calling, typing and memory
		1350	overhead by using function call syntax and a fixed number of parameters.
		1351
		1352	See the L<AE> manpage for details.
		1353
		1354	=cut
		1355
		1356	package AE;
		1357
		1358	our $VERSION = $AnyEvent::VERSION;
		1359
		1360	# fall back to the main API by default - backends and AnyEvent::Base
		1361	# implementations can overwrite these.
		1362
		1363	sub io($$$) {
		1364	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1365	}
		1366
		1367	sub timer($$$) {
		1368	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1369	}
		1370
		1371	sub signal($$) {
		1372	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1373	}
		1374
		1375	sub child($$) {
		1376	AnyEvent->child (pid => $_[0], cb => $_[1])
		1377	}
		1378
		1379	sub idle($) {
		1380	AnyEvent->idle (cb => $_[0])
		1381	}
		1382
		1383	sub cv(;&) {
		1384	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1385	}
		1386
		1387	sub now() {
		1388	AnyEvent->now
		1389	}
		1390
		1391	sub now_update() {
		1392	AnyEvent->now_update
		1393	}
		1394
		1395	sub time() {
		1396	AnyEvent->time
		1397	}
		1398
1096	package AnyEvent::Base;	1399	package AnyEvent::Base;
1097		1400
1098	# default implementations for many methods	1401	# default implementations for many methods
1099		1402
1100	BEGIN {	1403	sub time {
		1404	eval q{ # poor man's autoloading {}
		1405	# probe for availability of Time::HiRes
1101	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1406	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1407	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1102	*_time = \&Time::HiRes::time;	1408	*AE::time = \&Time::HiRes::time;
1103	# if (eval "use POSIX (); (POSIX::times())...	1409	# if (eval "use POSIX (); (POSIX::times())...
1104	} else {	1410	} else {
		1411	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1105	*_time = sub { time }; # epic fail	1412	*AE::time = sub (){ time }; # epic fail
		1413	}
		1414
		1415	*time = sub { AE::time }; # different prototypes
		1416	};
		1417	die if $@;
		1418
		1419	&time
		1420	}
		1421
		1422	*now = \&time;
		1423
		1424	sub now_update { }
		1425
		1426	# default implementation for ->condvar
		1427
		1428	sub condvar {
		1429	eval q{ # poor man's autoloading {}
		1430	*condvar = sub {
		1431	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1432	};
		1433
		1434	*AE::cv = sub (;&) {
		1435	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1436	};
		1437	};
		1438	die if $@;
		1439
		1440	&condvar
		1441	}
		1442
		1443	# default implementation for ->signal
		1444
		1445	our $HAVE_ASYNC_INTERRUPT;
		1446
		1447	sub _have_async_interrupt() {
		1448	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1449	&& eval "use Async::Interrupt 1.02 (); 1")
		1450	unless defined $HAVE_ASYNC_INTERRUPT;
		1451
		1452	$HAVE_ASYNC_INTERRUPT
		1453	}
		1454
		1455	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1456	our (%SIG_ASY, %SIG_ASY_W);
		1457	our ($SIG_COUNT, $SIG_TW);
		1458
		1459	# install a dummy wakeup watcher to reduce signal catching latency
		1460	# used by Impls
		1461	sub _sig_add() {
		1462	unless ($SIG_COUNT++) {
		1463	# try to align timer on a full-second boundary, if possible
		1464	my $NOW = AE::now;
		1465
		1466	$SIG_TW = AE::timer
		1467	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1468	$MAX_SIGNAL_LATENCY,
		1469	sub { } # just for the PERL_ASYNC_CHECK
		1470	;
1106	}	1471	}
1107	}	1472	}
1108		1473
1109	sub time { _time }	1474	sub _sig_del {
1110	sub now { _time }	1475	undef $SIG_TW
1111	sub now_update { }	1476	unless --$SIG_COUNT;
1112
1113	# default implementation for ->condvar
1114
1115	sub condvar {
1116	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1117	}	1477	}
1118		1478
1119	# default implementation for ->signal	1479	our $_sig_name_init; $_sig_name_init = sub {
		1480	eval q{ # poor man's autoloading {}
		1481	undef $_sig_name_init;
1120		1482
1121	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1483	if (_have_async_interrupt) {
		1484	*sig2num = \&Async::Interrupt::sig2num;
		1485	*sig2name = \&Async::Interrupt::sig2name;
		1486	} else {
		1487	require Config;
1122		1488
1123	sub _signal_exec {	1489	my %signame2num;
1124	sysread $SIGPIPE_R, my $dummy, 4;	1490	@signame2num{ split ' ', $Config::Config{sig_name} }
		1491	= split ' ', $Config::Config{sig_num};
1125		1492
1126	while (%SIG_EV) {	1493	my @signum2name;
1127	for (keys %SIG_EV) {	1494	@signum2name[values %signame2num] = keys %signame2num;
1128	delete $SIG_EV{$_};	1495
1129	$_->() for values %{ $SIG_CB{$_} || {} };	1496	*sig2num = sub($) {
		1497	$_[0] > 0 ? shift : $signame2num{+shift}
		1498	};
		1499	*sig2name = sub ($) {
		1500	$_[0] > 0 ? $signum2name[+shift] : shift
		1501	};
1130	}	1502	}
1131	}	1503	};
1132	}	1504	die if $@;
		1505	};
		1506
		1507	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1508	sub sig2name($) { &$_sig_name_init; &sig2name }
1133		1509
1134	sub signal {	1510	sub signal {
1135	my (undef, %arg) = @_;	1511	eval q{ # poor man's autoloading {}
		1512	# probe for availability of Async::Interrupt
		1513	if (_have_async_interrupt) {
		1514	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1136		1515
1137	unless ($SIGPIPE_R) {	1516	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1138	require Fcntl;	1517	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1139		1518
1140	if (AnyEvent::WIN32) {
1141	require AnyEvent::Util;
1142
1143	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1144	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1145	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1146	} else {	1519	} else {
		1520	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1521
		1522	if (AnyEvent::WIN32) {
		1523	require AnyEvent::Util;
		1524
		1525	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1526	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1527	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1528	} else {
1147	pipe $SIGPIPE_R, $SIGPIPE_W;	1529	pipe $SIGPIPE_R, $SIGPIPE_W;
1148	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1530	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1149	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1531	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1150		1532
1151	# not strictly required, as $^F is normally 2, but let's make sure...	1533	# not strictly required, as $^F is normally 2, but let's make sure...
1152	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1534	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1153	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1535	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1536	}
		1537
		1538	$SIGPIPE_R
		1539	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1540
		1541	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1154	}	1542	}
1155		1543
1156	$SIGPIPE_R	1544	*signal = $HAVE_ASYNC_INTERRUPT
1157	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1545	? sub {
		1546	my (undef, %arg) = @_;
1158		1547
1159	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1548	# async::interrupt
1160	}
1161
1162	my $signal = uc $arg{signal}	1549	my $signal = sig2num $arg{signal};
1163	or Carp::croak "required option 'signal' is missing";
1164
1165	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1550	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1551
		1552	$SIG_ASY{$signal} ||= new Async::Interrupt
		1553	cb => sub { undef $SIG_EV{$signal} },
		1554	signal => $signal,
		1555	pipe => [$SIGPIPE_R->filenos],
		1556	pipe_autodrain => 0,
		1557	;
		1558
		1559	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1560	}
		1561	: sub {
		1562	my (undef, %arg) = @_;
		1563
		1564	# pure perl
		1565	my $signal = sig2name $arg{signal};
		1566	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1567
1166	$SIG{$signal} ||= sub {	1568	$SIG{$signal} ||= sub {
1167	local $!;	1569	local $!;
1168	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1570	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1169	undef $SIG_EV{$signal};	1571	undef $SIG_EV{$signal};
		1572	};
		1573
		1574	# can't do signal processing without introducing races in pure perl,
		1575	# so limit the signal latency.
		1576	_sig_add;
		1577
		1578	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1579	}
		1580	;
		1581
		1582	*AnyEvent::Base::signal::DESTROY = sub {
		1583	my ($signal, $cb) = @{$_[0]};
		1584
		1585	_sig_del;
		1586
		1587	delete $SIG_CB{$signal}{$cb};
		1588
		1589	$HAVE_ASYNC_INTERRUPT
		1590	? delete $SIG_ASY{$signal}
		1591	: # delete doesn't work with older perls - they then
		1592	# print weird messages, or just unconditionally exit
		1593	# instead of getting the default action.
		1594	undef $SIG{$signal}
		1595	unless keys %{ $SIG_CB{$signal} };
		1596	};
		1597
		1598	*_signal_exec = sub {
		1599	$HAVE_ASYNC_INTERRUPT
		1600	? $SIGPIPE_R->drain
		1601	: sysread $SIGPIPE_R, (my $dummy), 9;
		1602
		1603	while (%SIG_EV) {
		1604	for (keys %SIG_EV) {
		1605	delete $SIG_EV{$_};
		1606	$_->() for values %{ $SIG_CB{$_} || {} };
		1607	}
		1608	}
		1609	};
1170	};	1610	};
		1611	die if $@;
1171		1612
1172	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1613	&signal
1173	}
1174
1175	sub AnyEvent::Base::signal::DESTROY {
1176	my ($signal, $cb) = @{$_[0]};
1177
1178	delete $SIG_CB{$signal}{$cb};
1179
1180	# delete doesn't work with older perls - they then
1181	# print weird messages, or just unconditionally exit
1182	# instead of getting the default action.
1183	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1184	}	1614	}
1185		1615
1186	# default implementation for ->child	1616	# default implementation for ->child
1187		1617
1188	our %PID_CB;	1618	our %PID_CB;
1189	our $CHLD_W;	1619	our $CHLD_W;
1190	our $CHLD_DELAY_W;	1620	our $CHLD_DELAY_W;
1191	our $WNOHANG;	1621	our $WNOHANG;
1192		1622
1193	sub _sigchld {	1623	# used by many Impl's
1194	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1624	sub _emit_childstatus($$) {
		1625	my (undef, $rpid, $rstatus) = @_;
		1626
		1627	$_->($rpid, $rstatus)
1195	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1628	for values %{ $PID_CB{$rpid} || {} },
1196	(values %{ $PID_CB{0} || {} });	1629	values %{ $PID_CB{0} || {} };
1197	}
1198	}	1630	}
1199		1631
1200	sub child {	1632	sub child {
		1633	eval q{ # poor man's autoloading {}
		1634	*_sigchld = sub {
		1635	my $pid;
		1636
		1637	AnyEvent->_emit_childstatus ($pid, $?)
		1638	while ($pid = waitpid -1, $WNOHANG) > 0;
		1639	};
		1640
		1641	*child = sub {
1201	my (undef, %arg) = @_;	1642	my (undef, %arg) = @_;
1202		1643
1203	defined (my $pid = $arg{pid} + 0)	1644	defined (my $pid = $arg{pid} + 0)
1204	or Carp::croak "required option 'pid' is missing";	1645	or Carp::croak "required option 'pid' is missing";
1205		1646
1206	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1647	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1207		1648
		1649	# WNOHANG is almost cetrainly 1 everywhere
		1650	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1651	? 1
1208	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1652	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1209		1653
1210	unless ($CHLD_W) {	1654	unless ($CHLD_W) {
1211	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1655	$CHLD_W = AE::signal CHLD => \&_sigchld;
1212	# child could be a zombie already, so make at least one round	1656	# child could be a zombie already, so make at least one round
1213	&_sigchld;	1657	&_sigchld;
1214	}	1658	}
1215		1659
1216	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1660	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1217	}	1661	};
1218		1662
1219	sub AnyEvent::Base::child::DESTROY {	1663	*AnyEvent::Base::child::DESTROY = sub {
1220	my ($pid, $cb) = @{$_[0]};	1664	my ($pid, $cb) = @{$_[0]};
1221		1665
1222	delete $PID_CB{$pid}{$cb};	1666	delete $PID_CB{$pid}{$cb};
1223	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1667	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1224		1668
1225	undef $CHLD_W unless keys %PID_CB;	1669	undef $CHLD_W unless keys %PID_CB;
		1670	};
		1671	};
		1672	die if $@;
		1673
		1674	&child
1226	}	1675	}
1227		1676
1228	# idle emulation is done by simply using a timer, regardless	1677	# idle emulation is done by simply using a timer, regardless
1229	# of whether the process is idle or not, and not letting	1678	# of whether the process is idle or not, and not letting
1230	# the callback use more than 50% of the time.	1679	# the callback use more than 50% of the time.
1231	sub idle {	1680	sub idle {
		1681	eval q{ # poor man's autoloading {}
		1682	*idle = sub {
1232	my (undef, %arg) = @_;	1683	my (undef, %arg) = @_;
1233		1684
1234	my ($cb, $w, $rcb) = $arg{cb};	1685	my ($cb, $w, $rcb) = $arg{cb};
1235		1686
1236	$rcb = sub {	1687	$rcb = sub {
1237	if ($cb) {	1688	if ($cb) {
1238	$w = _time;	1689	$w = _time;
1239	&$cb;	1690	&$cb;
1240	$w = _time - $w;	1691	$w = _time - $w;
1241		1692
1242	# never use more then 50% of the time for the idle watcher,	1693	# never use more then 50% of the time for the idle watcher,
1243	# within some limits	1694	# within some limits
1244	$w = 0.0001 if $w < 0.0001;	1695	$w = 0.0001 if $w < 0.0001;
1245	$w = 5 if $w > 5;	1696	$w = 5 if $w > 5;
1246		1697
1247	$w = AnyEvent->timer (after => $w, cb => $rcb);	1698	$w = AE::timer $w, 0, $rcb;
1248	} else {	1699	} else {
1249	# clean up...	1700	# clean up...
1250	undef $w;	1701	undef $w;
1251	undef $rcb;	1702	undef $rcb;
		1703	}
		1704	};
		1705
		1706	$w = AE::timer 0.05, 0, $rcb;
		1707
		1708	bless \\$cb, "AnyEvent::Base::idle"
1252	}	1709	};
		1710
		1711	*AnyEvent::Base::idle::DESTROY = sub {
		1712	undef $${$_[0]};
		1713	};
1253	};	1714	};
		1715	die if $@;
1254		1716
1255	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1717	&idle
1256
1257	bless \\$cb, "AnyEvent::Base::idle"
1258	}
1259
1260	sub AnyEvent::Base::idle::DESTROY {
1261	undef $${$_[0]};
1262	}	1718	}
1263		1719
1264	package AnyEvent::CondVar;	1720	package AnyEvent::CondVar;
1265		1721
1266	our @ISA = AnyEvent::CondVar::Base::;	1722	our @ISA = AnyEvent::CondVar::Base::;
1267		1723
1268	package AnyEvent::CondVar::Base;	1724	package AnyEvent::CondVar::Base;
1269		1725
1270	use overload	1726	#use overload
1271	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1727	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1272	fallback => 1;	1728	# fallback => 1;
		1729
		1730	# save 300+ kilobytes by dirtily hardcoding overloading
		1731	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1732	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1733	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1734	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1735
		1736	our $WAITING;
1273		1737
1274	sub _send {	1738	sub _send {
1275	# nop	1739	# nop
1276	}	1740	}
1277		1741
…		…
1290	sub ready {	1754	sub ready {
1291	$_[0]{_ae_sent}	1755	$_[0]{_ae_sent}
1292	}	1756	}
1293		1757
1294	sub _wait {	1758	sub _wait {
		1759	$WAITING
		1760	and !$_[0]{_ae_sent}
		1761	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1762
		1763	local $WAITING = 1;
1295	AnyEvent->one_event while !$_[0]{_ae_sent};	1764	AnyEvent->one_event while !$_[0]{_ae_sent};
1296	}	1765	}
1297		1766
1298	sub recv {	1767	sub recv {
1299	$_[0]->_wait;	1768	$_[0]->_wait;
…		…
1301	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1770	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1302	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1771	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1303	}	1772	}
1304		1773
1305	sub cb {	1774	sub cb {
1306	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1775	my $cv = shift;
		1776
		1777	@_
		1778	and $cv->{_ae_cb} = shift
		1779	and $cv->{_ae_sent}
		1780	and (delete $cv->{_ae_cb})->($cv);
		1781
1307	$_[0]{_ae_cb}	1782	$cv->{_ae_cb}
1308	}	1783	}
1309		1784
1310	sub begin {	1785	sub begin {
1311	++$_[0]{_ae_counter};	1786	++$_[0]{_ae_counter};
1312	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1787	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1361	C<PERL_ANYEVENT_MODEL>.	1836	C<PERL_ANYEVENT_MODEL>.
1362		1837
1363	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1838	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1364	model it chooses.	1839	model it chooses.
1365		1840
		1841	When set to C<8> or higher, then AnyEvent will report extra information on
		1842	which optional modules it loads and how it implements certain features.
		1843
1366	=item C<PERL_ANYEVENT_STRICT>	1844	=item C<PERL_ANYEVENT_STRICT>
1367		1845
1368	AnyEvent does not do much argument checking by default, as thorough	1846	AnyEvent does not do much argument checking by default, as thorough
1369	argument checking is very costly. Setting this variable to a true value	1847	argument checking is very costly. Setting this variable to a true value
1370	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1848	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1371	check the arguments passed to most method calls. If it finds any problems	1849	check the arguments passed to most method calls. If it finds any problems,
1372	it will croak.	1850	it will croak.
1373		1851
1374	In other words, enables "strict" mode.	1852	In other words, enables "strict" mode.
1375		1853
1376	Unlike C<use strict>, it is definitely recommended ot keep it off in	1854	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1377	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1855	>>, it is definitely recommended to keep it off in production. Keeping
1378	developing programs can be very useful, however.	1856	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1857	can be very useful, however.
1379		1858
1380	=item C<PERL_ANYEVENT_MODEL>	1859	=item C<PERL_ANYEVENT_MODEL>
1381		1860
1382	This can be used to specify the event model to be used by AnyEvent, before	1861	This can be used to specify the event model to be used by AnyEvent, before
1383	auto detection and -probing kicks in. It must be a string consisting	1862	auto detection and -probing kicks in. It must be a string consisting
…		…
1426		1905
1427	=item C<PERL_ANYEVENT_MAX_FORKS>	1906	=item C<PERL_ANYEVENT_MAX_FORKS>
1428		1907
1429	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1908	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1430	will create in parallel.	1909	will create in parallel.
		1910
		1911	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1912
		1913	The default value for the C<max_outstanding> parameter for the default DNS
		1914	resolver - this is the maximum number of parallel DNS requests that are
		1915	sent to the DNS server.
		1916
		1917	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1918
		1919	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1920	configuration) in the default resolver. When set to the empty string, no
		1921	default config will be used.
		1922
		1923	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1924
		1925	When neither C<ca_file> nor C<ca_path> was specified during
		1926	L<AnyEvent::TLS> context creation, and either of these environment
		1927	variables exist, they will be used to specify CA certificate locations
		1928	instead of a system-dependent default.
		1929
		1930	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1931
		1932	When these are set to C<1>, then the respective modules are not
		1933	loaded. Mostly good for testing AnyEvent itself.
1431		1934
1432	=back	1935	=back
1433		1936
1434	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1937	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1435		1938
…		…
1493	warn "read: $input\n"; # output what has been read	1996	warn "read: $input\n"; # output what has been read
1494	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1997	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1495	},	1998	},
1496	);	1999	);
1497		2000
1498	my $time_watcher; # can only be used once
1499
1500	sub new_timer {
1501	$timer = AnyEvent->timer (after => 1, cb => sub {	2001	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1502	warn "timeout\n"; # print 'timeout' about every second	2002	warn "timeout\n"; # print 'timeout' at most every second
1503	&new_timer; # and restart the time
1504	});	2003	});
1505	}
1506
1507	new_timer; # create first timer
1508		2004
1509	$cv->recv; # wait until user enters /^q/i	2005	$cv->recv; # wait until user enters /^q/i
1510		2006
1511	=head1 REAL-WORLD EXAMPLE	2007	=head1 REAL-WORLD EXAMPLE
1512		2008
…		…
1585		2081
1586	The actual code goes further and collects all errors (C<die>s, exceptions)	2082	The actual code goes further and collects all errors (C<die>s, exceptions)
1587	that occurred during request processing. The C<result> method detects	2083	that occurred during request processing. The C<result> method detects
1588	whether an exception as thrown (it is stored inside the $txn object)	2084	whether an exception as thrown (it is stored inside the $txn object)
1589	and just throws the exception, which means connection errors and other	2085	and just throws the exception, which means connection errors and other
1590	problems get reported tot he code that tries to use the result, not in a	2086	problems get reported to the code that tries to use the result, not in a
1591	random callback.	2087	random callback.
1592		2088
1593	All of this enables the following usage styles:	2089	All of this enables the following usage styles:
1594		2090
1595	1. Blocking:	2091	1. Blocking:
…		…
1643	through AnyEvent. The benchmark creates a lot of timers (with a zero	2139	through AnyEvent. The benchmark creates a lot of timers (with a zero
1644	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2140	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1645	which it is), lets them fire exactly once and destroys them again.	2141	which it is), lets them fire exactly once and destroys them again.
1646		2142
1647	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2143	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1648	distribution.	2144	distribution. It uses the L<AE> interface, which makes a real difference
		2145	for the EV and Perl backends only.
1649		2146
1650	=head3 Explanation of the columns	2147	=head3 Explanation of the columns
1651		2148
1652	I<watcher> is the number of event watchers created/destroyed. Since	2149	I<watcher> is the number of event watchers created/destroyed. Since
1653	different event models feature vastly different performances, each event	2150	different event models feature vastly different performances, each event
…		…
1674	watcher.	2171	watcher.
1675		2172
1676	=head3 Results	2173	=head3 Results
1677		2174
1678	name watchers bytes create invoke destroy comment	2175	name watchers bytes create invoke destroy comment
1679	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2176	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1680	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2177	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1681	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2178	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1682	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2179	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1683	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2180	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1684	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2181	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2182	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2183	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1685	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2184	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1686	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2185	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1687	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2186	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1688	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2187	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1689		2188
1690	=head3 Discussion	2189	=head3 Discussion
1691		2190
1692	The benchmark does I<not> measure scalability of the event loop very	2191	The benchmark does I<not> measure scalability of the event loop very
1693	well. For example, a select-based event loop (such as the pure perl one)	2192	well. For example, a select-based event loop (such as the pure perl one)
…		…
1705	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2204	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1706	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2205	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1707	cycles with POE.	2206	cycles with POE.
1708		2207
1709	C<EV> is the sole leader regarding speed and memory use, which are both	2208	C<EV> is the sole leader regarding speed and memory use, which are both
1710	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2209	maximal/minimal, respectively. When using the L<AE> API there is zero
		2210	overhead (when going through the AnyEvent API create is about 5-6 times
		2211	slower, with other times being equal, so still uses far less memory than
1711	far less memory than any other event loop and is still faster than Event	2212	any other event loop and is still faster than Event natively).
1712	natively.
1713		2213
1714	The pure perl implementation is hit in a few sweet spots (both the	2214	The pure perl implementation is hit in a few sweet spots (both the
1715	constant timeout and the use of a single fd hit optimisations in the perl	2215	constant timeout and the use of a single fd hit optimisations in the perl
1716	interpreter and the backend itself). Nevertheless this shows that it	2216	interpreter and the backend itself). Nevertheless this shows that it
1717	adds very little overhead in itself. Like any select-based backend its	2217	adds very little overhead in itself. Like any select-based backend its
1718	performance becomes really bad with lots of file descriptors (and few of	2218	performance becomes really bad with lots of file descriptors (and few of
1719	them active), of course, but this was not subject of this benchmark.	2219	them active), of course, but this was not subject of this benchmark.
1720		2220
1721	The C<Event> module has a relatively high setup and callback invocation	2221	The C<Event> module has a relatively high setup and callback invocation
1722	cost, but overall scores in on the third place.	2222	cost, but overall scores in on the third place.
		2223
		2224	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2225	when using its pure perl backend.
1723		2226
1724	C<Glib>'s memory usage is quite a bit higher, but it features a	2227	C<Glib>'s memory usage is quite a bit higher, but it features a
1725	faster callback invocation and overall ends up in the same class as	2228	faster callback invocation and overall ends up in the same class as
1726	C<Event>. However, Glib scales extremely badly, doubling the number of	2229	C<Event>. However, Glib scales extremely badly, doubling the number of
1727	watchers increases the processing time by more than a factor of four,	2230	watchers increases the processing time by more than a factor of four,
…		…
1788	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2291	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1789	(1%) are active. This mirrors the activity of large servers with many	2292	(1%) are active. This mirrors the activity of large servers with many
1790	connections, most of which are idle at any one point in time.	2293	connections, most of which are idle at any one point in time.
1791		2294
1792	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2295	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1793	distribution.	2296	distribution. It uses the L<AE> interface, which makes a real difference
		2297	for the EV and Perl backends only.
1794		2298
1795	=head3 Explanation of the columns	2299	=head3 Explanation of the columns
1796		2300
1797	I<sockets> is the number of sockets, and twice the number of "servers" (as	2301	I<sockets> is the number of sockets, and twice the number of "servers" (as
1798	each server has a read and write socket end).	2302	each server has a read and write socket end).
…		…
1805	it to another server. This includes deleting the old timeout and creating	2309	it to another server. This includes deleting the old timeout and creating
1806	a new one that moves the timeout into the future.	2310	a new one that moves the timeout into the future.
1807		2311
1808	=head3 Results	2312	=head3 Results
1809		2313
1810	name sockets create request	2314	name sockets create request
1811	EV 20000 69.01 11.16	2315	EV 20000 62.66 7.99
1812	Perl 20000 73.32 35.87	2316	Perl 20000 68.32 32.64
1813	Event 20000 212.62 257.32	2317	IOAsync 20000 174.06 101.15 epoll
1814	Glib 20000 651.16 1896.30	2318	IOAsync 20000 174.67 610.84 poll
		2319	Event 20000 202.69 242.91
		2320	Glib 20000 557.01 1689.52
1815	POE 20000 349.67 12317.24 uses POE::Loop::Event	2321	POE 20000 341.54 12086.32 uses POE::Loop::Event
1816		2322
1817	=head3 Discussion	2323	=head3 Discussion
1818		2324
1819	This benchmark I<does> measure scalability and overall performance of the	2325	This benchmark I<does> measure scalability and overall performance of the
1820	particular event loop.	2326	particular event loop.
…		…
1822	EV is again fastest. Since it is using epoll on my system, the setup time	2328	EV is again fastest. Since it is using epoll on my system, the setup time
1823	is relatively high, though.	2329	is relatively high, though.
1824		2330
1825	Perl surprisingly comes second. It is much faster than the C-based event	2331	Perl surprisingly comes second. It is much faster than the C-based event
1826	loops Event and Glib.	2332	loops Event and Glib.
		2333
		2334	IO::Async performs very well when using its epoll backend, and still quite
		2335	good compared to Glib when using its pure perl backend.
1827		2336
1828	Event suffers from high setup time as well (look at its code and you will	2337	Event suffers from high setup time as well (look at its code and you will
1829	understand why). Callback invocation also has a high overhead compared to	2338	understand why). Callback invocation also has a high overhead compared to
1830	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2339	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1831	uses select or poll in basically all documented configurations.	2340	uses select or poll in basically all documented configurations.
…		…
1900		2409
1901	Recently I was told about the benchmark in the IO::Lambda manpage, which	2410	Recently I was told about the benchmark in the IO::Lambda manpage, which
1902	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark	2411	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
1903	simply compares IO::Lambda with POE, and IO::Lambda looks better (which	2412	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
1904	shouldn't come as a surprise to anybody). As such, the benchmark is	2413	shouldn't come as a surprise to anybody). As such, the benchmark is
1905	fine, and shows that the AnyEvent backend from IO::Lambda isn't very	2414	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
1906	optimal. But how would AnyEvent compare when used without the extra	2415	very optimal. But how would AnyEvent compare when used without the extra
1907	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.	2416	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
1908		2417
1909	The benchmark itself creates an echo-server, and then, for 500 times,	2418	The benchmark itself creates an echo-server, and then, for 500 times,
1910	connects to the echo server, sends a line, waits for the reply, and then	2419	connects to the echo server, sends a line, waits for the reply, and then
1911	creates the next connection. This is a rather bad benchmark, as it doesn't	2420	creates the next connection. This is a rather bad benchmark, as it doesn't
1912	test the efficiency of the framework, but it is a benchmark nevertheless.	2421	test the efficiency of the framework or much non-blocking I/O, but it is a
		2422	benchmark nevertheless.
1913		2423
1914	name runtime	2424	name runtime
1915	Lambda/select 0.330 sec	2425	Lambda/select 0.330 sec
1916	+ optimized 0.122 sec	2426	+ optimized 0.122 sec
1917	Lambda/AnyEvent 0.327 sec	2427	Lambda/AnyEvent 0.327 sec
…		…
1923		2433
1924	AnyEvent/select/nb 0.085 sec	2434	AnyEvent/select/nb 0.085 sec
1925	AnyEvent/EV/nb 0.068 sec	2435	AnyEvent/EV/nb 0.068 sec
1926	+state machine 0.134 sec	2436	+state machine 0.134 sec
1927		2437
1928	The benchmark is also a bit unfair (my fault) - the IO::Lambda	2438	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
1929	benchmarks actually make blocking connects and use 100% blocking I/O,	2439	benchmarks actually make blocking connects and use 100% blocking I/O,
1930	defeating the purpose of an event-based solution. All of the newly	2440	defeating the purpose of an event-based solution. All of the newly
1931	written AnyEvent benchmarks use 100% non-blocking connects (using	2441	written AnyEvent benchmarks use 100% non-blocking connects (using
1932	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS	2442	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
1933	resolver), so AnyEvent is at a disadvantage here as non-blocking connects	2443	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
1934	generally require a lot more bookkeeping and event handling than blocking	2444	generally require a lot more bookkeeping and event handling than blocking
1935	connects (which involve a single syscall only).	2445	connects (which involve a single syscall only).
1936		2446
1937	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which	2447	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
1938	offers similar expressive power as POE and IO::Lambda (using conventional	2448	offers similar expressive power as POE and IO::Lambda, using conventional
1939	Perl syntax), which means both the echo server and the client are 100%	2449	Perl syntax. This means that both the echo server and the client are 100%
1940	non-blocking w.r.t. I/O, further placing it at a disadvantage.	2450	non-blocking, further placing it at a disadvantage.
1941		2451
1942	As you can see, AnyEvent + EV even beats the hand-optimised "raw sockets	2452	As you can see, the AnyEvent + EV combination even beats the
1943	benchmark", while AnyEvent + its pure perl backend easily beats	2453	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
1944	IO::Lambda and POE.	2454	backend easily beats IO::Lambda and POE.
1945		2455
1946	And even the 100% non-blocking version written using the high-level (and	2456	And even the 100% non-blocking version written using the high-level (and
1947	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda,	2457	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2458	higher level ("unoptimised") abstractions by a large margin, even though
1948	even thought it does all of DNS, tcp-connect and socket I/O in a	2459	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
1949	non-blocking way.
1950		2460
1951	The two AnyEvent benchmarks can be found as F<eg/ae0.pl> and F<eg/ae2.pl>	2461	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
1952	in the AnyEvent distribution, the remaining benchmarks are part of the	2462	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
1953	IO::lambda distribution and were used without any changes.	2463	part of the IO::Lambda distribution and were used without any changes.
1954		2464
1955		2465
1956	=head1 SIGNALS	2466	=head1 SIGNALS
1957		2467
1958	AnyEvent currently installs handlers for these signals:	2468	AnyEvent currently installs handlers for these signals:
…		…
1962	=item SIGCHLD	2472	=item SIGCHLD
1963		2473
1964	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2474	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1965	emulation for event loops that do not support them natively. Also, some	2475	emulation for event loops that do not support them natively. Also, some
1966	event loops install a similar handler.	2476	event loops install a similar handler.
		2477
		2478	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2479	AnyEvent will reset it to default, to avoid losing child exit statuses.
1967		2480
1968	=item SIGPIPE	2481	=item SIGPIPE
1969		2482
1970	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2483	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1971	when AnyEvent gets loaded.	2484	when AnyEvent gets loaded.
…		…
1983		2496
1984	=back	2497	=back
1985		2498
1986	=cut	2499	=cut
1987		2500
		2501	undef $SIG{CHLD}
		2502	if $SIG{CHLD} eq 'IGNORE';
		2503
1988	$SIG{PIPE} = sub { }	2504	$SIG{PIPE} = sub { }
1989	unless defined $SIG{PIPE};	2505	unless defined $SIG{PIPE};
1990		2506
		2507	=head1 RECOMMENDED/OPTIONAL MODULES
		2508
		2509	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2510	it's built-in modules) are required to use it.
		2511
		2512	That does not mean that AnyEvent won't take advantage of some additional
		2513	modules if they are installed.
		2514
		2515	This section explains which additional modules will be used, and how they
		2516	affect AnyEvent's operation.
		2517
		2518	=over 4
		2519
		2520	=item L<Async::Interrupt>
		2521
		2522	This slightly arcane module is used to implement fast signal handling: To
		2523	my knowledge, there is no way to do completely race-free and quick
		2524	signal handling in pure perl. To ensure that signals still get
		2525	delivered, AnyEvent will start an interval timer to wake up perl (and
		2526	catch the signals) with some delay (default is 10 seconds, look for
		2527	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2528
		2529	If this module is available, then it will be used to implement signal
		2530	catching, which means that signals will not be delayed, and the event loop
		2531	will not be interrupted regularly, which is more efficient (and good for
		2532	battery life on laptops).
		2533
		2534	This affects not just the pure-perl event loop, but also other event loops
		2535	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2536
		2537	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2538	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2539	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2540	does nothing for those backends.
		2541
		2542	=item L<EV>
		2543
		2544	This module isn't really "optional", as it is simply one of the backend
		2545	event loops that AnyEvent can use. However, it is simply the best event
		2546	loop available in terms of features, speed and stability: It supports
		2547	the AnyEvent API optimally, implements all the watcher types in XS, does
		2548	automatic timer adjustments even when no monotonic clock is available,
		2549	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2550	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2551	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2552
		2553	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2554	then this module will do nothing for you.
		2555
		2556	=item L<Guard>
		2557
		2558	The guard module, when used, will be used to implement
		2559	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2560	lot less memory), but otherwise doesn't affect guard operation much. It is
		2561	purely used for performance.
		2562
		2563	=item L<JSON> and L<JSON::XS>
		2564
		2565	One of these modules is required when you want to read or write JSON data
		2566	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2567	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2568
		2569	=item L<Net::SSLeay>
		2570
		2571	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2572	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2573	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2574
		2575	=item L<Time::HiRes>
		2576
		2577	This module is part of perl since release 5.008. It will be used when the
		2578	chosen event library does not come with a timing source on it's own. The
		2579	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2580	try to use a monotonic clock for timing stability.
		2581
		2582	=back
		2583
1991		2584
1992	=head1 FORK	2585	=head1 FORK
1993		2586
1994	Most event libraries are not fork-safe. The ones who are usually are	2587	Most event libraries are not fork-safe. The ones who are usually are
1995	because they rely on inefficient but fork-safe C<select> or C<poll>	2588	because they rely on inefficient but fork-safe C<select> or C<poll> calls
1996	calls. Only L<EV> is fully fork-aware.	2589	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2590	are usually badly thought-out hacks that are incompatible with fork in
		2591	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2592	continue event-processing in both parent and child (or both, if you know
		2593	what you are doing).
		2594
		2595	This means that, in general, you cannot fork and do event processing in
		2596	the child if the event library was initialised before the fork (which
		2597	usually happens when the first AnyEvent watcher is created, or the library
		2598	is loaded).
1997		2599
1998	If you have to fork, you must either do so I<before> creating your first	2600	If you have to fork, you must either do so I<before> creating your first
1999	watcher OR you must not use AnyEvent at all in the child.	2601	watcher OR you must not use AnyEvent at all in the child OR you must do
		2602	something completely out of the scope of AnyEvent.
		2603
		2604	The problem of doing event processing in the parent I<and> the child
		2605	is much more complicated: even for backends that I<are> fork-aware or
		2606	fork-safe, their behaviour is not usually what you want: fork clones all
		2607	watchers, that means all timers, I/O watchers etc. are active in both
		2608	parent and child, which is almost never what you want. USing C<exec>
		2609	to start worker children from some kind of manage rprocess is usually
		2610	preferred, because it is much easier and cleaner, at the expense of having
		2611	to have another binary.
2000		2612
2001		2613
2002	=head1 SECURITY CONSIDERATIONS	2614	=head1 SECURITY CONSIDERATIONS
2003		2615
2004	AnyEvent can be forced to load any event model via	2616	AnyEvent can be forced to load any event model via
…		…
2018	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2630	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
2019	be used to probe what backend is used and gain other information (which is	2631	be used to probe what backend is used and gain other information (which is
2020	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2632	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
2021	$ENV{PERL_ANYEVENT_STRICT}.	2633	$ENV{PERL_ANYEVENT_STRICT}.
2022		2634
		2635	Note that AnyEvent will remove I<all> environment variables starting with
		2636	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2637	enabled.
		2638
2023		2639
2024	=head1 BUGS	2640	=head1 BUGS
2025		2641
2026	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2642	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
2027	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2643	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
…		…
2038	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2654	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2039		2655
2040	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2656	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2041	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2657	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2042	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2658	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2043	L<AnyEvent::Impl::POE>.	2659	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2044		2660
2045	Non-blocking file handles, sockets, TCP clients and	2661	Non-blocking file handles, sockets, TCP clients and
2046	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2662	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2047		2663
2048	Asynchronous DNS: L<AnyEvent::DNS>.	2664	Asynchronous DNS: L<AnyEvent::DNS>.
2049		2665
2050	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2666	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2667	L<Coro::Event>,
2051		2668
2052	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2669	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2670	L<AnyEvent::HTTP>.
2053		2671
2054		2672
2055	=head1 AUTHOR	2673	=head1 AUTHOR
2056		2674
2057	Marc Lehmann <schmorp@schmorp.de>	2675	Marc Lehmann <schmorp@schmorp.de>

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