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Revision 1.329 by root, Sun Jul 11 05:44:22 2010 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
6	event loops.	6	and POE are various supported event loops/environments.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
12	# file descriptor readable	15	# file handle or descriptor readable
13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14		17
15	# one-shot or repeating timers	18	# one-shot or repeating timers
16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
…		…
40	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
41		44
42	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
43	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
		48
		49	=head1 SUPPORT
		50
		51	There is a mailinglist for discussing all things AnyEvent, and an IRC
		52	channel, too.
		53
		54	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		55	Repository>, at L<http://anyevent.schmorp.de>, for more info.
45		56
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	57	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		58
48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	59	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49	nowadays. So what is different about AnyEvent?	60	nowadays. So what is different about AnyEvent?
…		…
127	use AnyEvent;	138	use AnyEvent;
128		139
129	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
130		141
131	The I<likely> means that, if any module loads another event model and	142	The I<likely> means that, if any module loads another event model and
132	starts using it, all bets are off. Maybe you should tell their authors to	143	starts using it, all bets are off - this case should be very rare though,
133	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
134		146
135	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called
136	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	148	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
137	explicitly and enjoy the high availability of that event loop :)	149	explicitly and enjoy the high availability of that event loop :)
138		150
…		…
173	my variables are only visible after the statement in which they are	185	my variables are only visible after the statement in which they are
174	declared.	186	declared.
175		187
176	=head2 I/O WATCHERS	188	=head2 I/O WATCHERS
177		189
		190	$w = AnyEvent->io (
		191	fh => <filehandle_or_fileno>,
		192	poll => <"r" or "w">,
		193	cb => <callback>,
		194	);
		195
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	196	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
180		198
181	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch	199	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
182	for events (AnyEvent might or might not keep a reference to this file	200	for events (AnyEvent might or might not keep a reference to this file
183	handle). Note that only file handles pointing to things for which	201	handle). Note that only file handles pointing to things for which
184	non-blocking operation makes sense are allowed. This includes sockets,	202	non-blocking operation makes sense are allowed. This includes sockets,
185	most character devices, pipes, fifos and so on, but not for example files	203	most character devices, pipes, fifos and so on, but not for example files
186	or block devices.	204	or block devices.
…		…
211	undef $w;	229	undef $w;
212	});	230	});
213		231
214	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
215		233
		234	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		235
		236	$w = AnyEvent->timer (
		237	after => <fractional_seconds>,
		238	interval => <fractional_seconds>,
		239	cb => <callback>,
		240	);
		241
216	You can create a time watcher by calling the C<< AnyEvent->timer >>	242	You can create a time watcher by calling the C<< AnyEvent->timer >>
217	method with the following mandatory arguments:	243	method with the following mandatory arguments:
218		244
219	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
220	supported) the callback should be invoked. C<cb> is the callback to invoke	246	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
341	might affect timers and time-outs.	367	might affect timers and time-outs.
342		368
343	When this is the case, you can call this method, which will update the	369	When this is the case, you can call this method, which will update the
344	event loop's idea of "current time".	370	event loop's idea of "current time".
345		371
		372	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		373	when mod_perl executes the script, then the event loop will have the wrong
		374	idea about the "current time" (being potentially far in the past, when the
		375	script ran the last time). In that case you should arrange a call to C<<
		376	AnyEvent->now_update >> each time the web server process wakes up again
		377	(e.g. at the start of your script, or in a handler).
		378
346	Note that updating the time I<might> cause some events to be handled.	379	Note that updating the time I<might> cause some events to be handled.
347		380
348	=back	381	=back
349		382
350	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351		386
352	You can watch for signals using a signal watcher, C<signal> is the signal	387	You can watch for signals using a signal watcher, C<signal> is the signal
353	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	388	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
355		390
…		…
361	invocation, and callback invocation will be synchronous. Synchronous means	396	invocation, and callback invocation will be synchronous. Synchronous means
362	that it might take a while until the signal gets handled by the process,	397	that it might take a while until the signal gets handled by the process,
363	but it is guaranteed not to interrupt any other callbacks.	398	but it is guaranteed not to interrupt any other callbacks.
364		399
365	The main advantage of using these watchers is that you can share a signal	400	The main advantage of using these watchers is that you can share a signal
366	between multiple watchers.	401	between multiple watchers, and AnyEvent will ensure that signals will not
		402	interrupt your program at bad times.
367		403
368	This watcher might use C<%SIG>, so programs overwriting those signals	404	This watcher might use C<%SIG> (depending on the event loop used),
369	directly will likely not work correctly.	405	so programs overwriting those signals directly will likely not work
		406	correctly.
370		407
371	Example: exit on SIGINT	408	Example: exit on SIGINT
372		409
373	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
374		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling) or
		421	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		422	latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
		429	=head3 Signal Races, Delays and Workarounds
		430
		431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		432	callbacks to signals in a generic way, which is a pity, as you cannot
		433	do race-free signal handling in perl, requiring C libraries for
		434	this. AnyEvent will try to do it's best, which means in some cases,
		435	signals will be delayed. The maximum time a signal might be delayed is
		436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		437	variable can be changed only before the first signal watcher is created,
		438	and should be left alone otherwise. This variable determines how often
		439	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		440	will cause fewer spurious wake-ups, which is better for power and CPU
		441	saving.
		442
		443	All these problems can be avoided by installing the optional
		444	L<Async::Interrupt> module, which works with most event loops. It will not
		445	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		446	(and not with L<POE> currently, as POE does it's own workaround with
		447	one-second latency). For those, you just have to suffer the delays.
		448
375	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
376		450
		451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		452
377	You can also watch on a child process exit and catch its exit status.	453	You can also watch on a child process exit and catch its exit status.
378		454
379	The child process is specified by the C<pid> argument (if set to C<0>, it	455	The child process is specified by the C<pid> argument (one some backends,
380	watches for any child process exit). The watcher will triggered only when	456	using C<0> watches for any child process exit, on others this will
381	the child process has finished and an exit status is available, not on	457	croak). The watcher will be triggered only when the child process has
382	any trace events (stopped/continued).	458	finished and an exit status is available, not on any trace events
		459	(stopped/continued).
383		460
384	The callback will be called with the pid and exit status (as returned by	461	The callback will be called with the pid and exit status (as returned by
385	waitpid), so unlike other watcher types, you I<can> rely on child watcher	462	waitpid), so unlike other watcher types, you I<can> rely on child watcher
386	callback arguments.	463	callback arguments.
387		464
…		…
392		469
393	There is a slight catch to child watchers, however: you usually start them	470	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	471	I<after> the child process was created, and this means the process could
395	have exited already (and no SIGCHLD will be sent anymore).	472	have exited already (and no SIGCHLD will be sent anymore).
396		473
397	Not all event models handle this correctly (POE doesn't), but even for	474	Not all event models handle this correctly (neither POE nor IO::Async do,
		475	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	476	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).	477	the process exits (i.e. before you fork in the first place). AnyEvent's
		478	pure perl event loop handles all cases correctly regardless of when you
		479	start the watcher.
400		480
401	This means you cannot create a child watcher as the very first thing in an	481	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	482	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>).	483	watcher before you C<fork> the child (alternatively, you can call
		484	C<AnyEvent::detect>).
		485
		486	As most event loops do not support waiting for child events, they will be
		487	emulated by AnyEvent in most cases, in which the latency and race problems
		488	mentioned in the description of signal watchers apply.
404		489
405	Example: fork a process and wait for it	490	Example: fork a process and wait for it
406		491
407	my $done = AnyEvent->condvar;	492	my $done = AnyEvent->condvar;
408		493
…		…
420	# do something else, then wait for process exit	505	# do something else, then wait for process exit
421	$done->recv;	506	$done->recv;
422		507
423	=head2 IDLE WATCHERS	508	=head2 IDLE WATCHERS
424		509
425	Sometimes there is a need to do something, but it is not so important	510	$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		511
430	Idle watchers ideally get invoked when the event loop has nothing	512	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	513	either the watcher is destroyed or new events have been detected.
432	events. Instead of blocking, the idle watcher is invoked.
433		514
434	Most event loops unfortunately do not really support idle watchers (only	515	Idle watchers are useful when there is a need to do something, but it
		516	is not so important (or wise) to do it instantly. The callback will be
		517	invoked only when there is "nothing better to do", which is usually
		518	defined as "all outstanding events have been handled and no new events
		519	have been detected". That means that idle watchers ideally get invoked
		520	when the event loop has just polled for new events but none have been
		521	detected. Instead of blocking to wait for more events, the idle watchers
		522	will be invoked.
		523
		524	Unfortunately, most event loops do not really support idle watchers (only
435	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	525	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
436	will simply call the callback "from time to time".	526	will simply call the callback "from time to time".
437		527
438	Example: read lines from STDIN, but only process them when the	528	Example: read lines from STDIN, but only process them when the
439	program is otherwise idle:	529	program is otherwise idle:
…		…
455	});	545	});
456	});	546	});
457		547
458	=head2 CONDITION VARIABLES	548	=head2 CONDITION VARIABLES
459		549
		550	$cv = AnyEvent->condvar;
		551
		552	$cv->send (<list>);
		553	my @res = $cv->recv;
		554
460	If you are familiar with some event loops you will know that all of them	555	If you are familiar with some event loops you will know that all of them
461	require you to run some blocking "loop", "run" or similar function that	556	require you to run some blocking "loop", "run" or similar function that
462	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
463		558
464	AnyEvent is different, it expects somebody else to run the event loop and	559	AnyEvent is slightly different: it expects somebody else to run the event
465	will only block when necessary (usually when told by the user).	560	loop and will only block when necessary (usually when told by the user).
466		561
467	The instrument to do that is called a "condition variable", so called	562	The tool to do that is called a "condition variable", so called because
468	because they represent a condition that must become true.	563	they represent a condition that must become true.
		564
		565	Now is probably a good time to look at the examples further below.
469		566
470	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
471	>> method, usually without arguments. The only argument pair allowed is	568	>> 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	569	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	570	becomes true, with the condition variable as the first argument (but not
475	the results).	571	the results).
476		572
477	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
478	by calling the C<send> method (or calling the condition variable as if it	574	by calling the C<send> method (or calling the condition variable as if it
479	were a callback, read about the caveats in the description for the C<<	575	were a callback, read about the caveats in the description for the C<<
480	->send >> method).	576	->send >> method).
481		577
482	Condition variables are similar to callbacks, except that you can	578	Since condition variables are the most complex part of the AnyEvent API, here are
483	optionally wait for them. They can also be called merge points - points	579	some different mental models of what they are - pick the ones you can connect to:
484	in time where multiple outstanding events have been processed. And yet	580
485	another way to call them is transactions - each condition variable can be	581	=over 4
486	used to represent a transaction, which finishes at some point and delivers	582
487	a result.	583	=item * Condition variables are like callbacks - you can call them (and pass them instead
		584	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		585
		586	=item * Condition variables are signals - one side can emit or send them,
		587	the other side can wait for them, or install a handler that is called when
		588	the signal fires.
		589
		590	=item * Condition variables are like "Merge Points" - points in your program
		591	where you merge multiple independent results/control flows into one.
		592
		593	=item * Condition variables represent a transaction - function that start
		594	some kind of transaction can return them, leaving the caller the choice
		595	between waiting in a blocking fashion, or setting a callback.
		596
		597	=item * Condition variables represent future values, or promises to deliver
		598	some result, long before the result is available.
		599
		600	=back
488		601
489	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
490	for example, if you write a module that does asynchronous http requests,	603	for example, if you write a module that does asynchronous http requests,
491	then a condition variable would be the ideal candidate to signal the	604	then a condition variable would be the ideal candidate to signal the
492	availability of results. The user can either act when the callback is	605	availability of results. The user can either act when the callback is
…		…
513	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
514	for the send to occur.	627	for the send to occur.
515		628
516	Example: wait for a timer.	629	Example: wait for a timer.
517		630
518	# wait till the result is ready	631	# condition: "wait till the timer is fired"
519	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
520		633
521	# do something such as adding a timer	634	# create the timer - we could wait for, say
522	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
523	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
524	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
525	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
526	after => 1,	639	after => 1,
527	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
528	);	641	);
529		642
530	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
531	# calls send	644	# calls ->send
532	$result_ready->recv;	645	$timer_fired->recv;
533		646
534	Example: wait for a timer, but take advantage of the fact that	647	Example: wait for a timer, but take advantage of the fact that condition
535	condition variables are also code references.	648	variables are also callable directly.
536		649
537	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
538	my $delay = AnyEvent->timer (after => 5, cb => $done);	651	my $delay = AnyEvent->timer (after => 5, cb => $done);
539	$done->recv;	652	$done->recv;
540		653
…		…
546		659
547	...	660	...
548		661
549	my @info = $couchdb->info->recv;	662	my @info = $couchdb->info->recv;
550		663
551	And this is how you would just ste a callback to be called whenever the	664	And this is how you would just set a callback to be called whenever the
552	results are available:	665	results are available:
553		666
554	$couchdb->info->cb (sub {	667	$couchdb->info->cb (sub {
555	my @info = $_[0]->recv;	668	my @info = $_[0]->recv;
556	});	669	});
…		…
574	immediately from within send.	687	immediately from within send.
575		688
576	Any arguments passed to the C<send> call will be returned by all	689	Any arguments passed to the C<send> call will be returned by all
577	future C<< ->recv >> calls.	690	future C<< ->recv >> calls.
578		691
579	Condition variables are overloaded so one can call them directly	692	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	693	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	694	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		695
588	=item $cv->croak ($error)	696	=item $cv->croak ($error)
589		697
590	Similar to send, but causes all call's to C<< ->recv >> to invoke	698	Similar to send, but causes all call's to C<< ->recv >> to invoke
591	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
592		700
593	This can be used to signal any errors to the condition variable	701	This can be used to signal any errors to the condition variable
594	user/consumer.	702	user/consumer. Doing it this way instead of calling C<croak> directly
		703	delays the error detetcion, but has the overwhelmign advantage that it
		704	diagnoses the error at the place where the result is expected, and not
		705	deep in some event clalback without connection to the actual code causing
		706	the problem.
595		707
596	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
597		709
598	=item $cv->end	710	=item $cv->end
599
600	These two methods are EXPERIMENTAL and MIGHT CHANGE.
601		711
602	These two methods can be used to combine many transactions/events into	712	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	713	one. For example, a function that pings many hosts in parallel might want
604	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
605		715
606	Every call to C<< ->begin >> will increment a counter, and every call to	716	Every call to C<< ->begin >> will increment a counter, and every call to
607	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	717	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
608	>>, the (last) callback passed to C<begin> will be executed. That callback	718	>>, the (last) callback passed to C<begin> will be executed, passing the
609	is I<supposed> to call C<< ->send >>, but that is not required. If no	719	condvar as first argument. That callback is I<supposed> to call C<< ->send
610	callback was set, C<send> will be called without any arguments.	720	>>, but that is not required. If no group callback was set, C<send> will
		721	be called without any arguments.
611		722
612	Let's clarify this with the ping example:	723	You can think of C<< $cv->send >> giving you an OR condition (one call
		724	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		725	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		726
		727	Let's start with a simple example: you have two I/O watchers (for example,
		728	STDOUT and STDERR for a program), and you want to wait for both streams to
		729	close before activating a condvar:
613		730
614	my $cv = AnyEvent->condvar;	731	my $cv = AnyEvent->condvar;
615		732
		733	$cv->begin; # first watcher
		734	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		735	defined sysread $fh1, my $buf, 4096
		736	or $cv->end;
		737	});
		738
		739	$cv->begin; # second watcher
		740	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		741	defined sysread $fh2, my $buf, 4096
		742	or $cv->end;
		743	});
		744
		745	$cv->recv;
		746
		747	This works because for every event source (EOF on file handle), there is
		748	one call to C<begin>, so the condvar waits for all calls to C<end> before
		749	sending.
		750
		751	The ping example mentioned above is slightly more complicated, as the
		752	there are results to be passwd back, and the number of tasks that are
		753	begung can potentially be zero:
		754
		755	my $cv = AnyEvent->condvar;
		756
616	my %result;	757	my %result;
617	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
618		759
619	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
620	$cv->begin;	761	$cv->begin;
621	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
622	$result{$host} = ...;	763	$result{$host} = ...;
…		…
637	loop, which serves two important purposes: first, it sets the callback	778	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	779	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	780	C<send> is called even when C<no> hosts are being pinged (the loop
640	doesn't execute once).	781	doesn't execute once).
641		782
642	This is the general pattern when you "fan out" into multiple subrequests:	783	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>	784	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	785	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>.	786	subrequest you start, call C<begin> and for each subrequest you finish,
		787	call C<end>.
646		788
647	=back	789	=back
648		790
649	=head3 METHODS FOR CONSUMERS	791	=head3 METHODS FOR CONSUMERS
650		792
…		…
666	function will call C<croak>.	808	function will call C<croak>.
667		809
668	In list context, all parameters passed to C<send> will be returned,	810	In list context, all parameters passed to C<send> will be returned,
669	in scalar context only the first one will be returned.	811	in scalar context only the first one will be returned.
670		812
		813	Note that doing a blocking wait in a callback is not supported by any
		814	event loop, that is, recursive invocation of a blocking C<< ->recv
		815	>> is not allowed, and the C<recv> call will C<croak> if such a
		816	condition is detected. This condition can be slightly loosened by using
		817	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		818	any thread that doesn't run the event loop itself.
		819
671	Not all event models support a blocking wait - some die in that case	820	Not all event models support a blocking wait - some die in that case
672	(programs might want to do that to stay interactive), so I<if you are	821	(programs might want to do that to stay interactive), so I<if you are
673	using this from a module, never require a blocking wait>, but let the	822	using this from a module, never require a blocking wait>. Instead, let the
674	caller decide whether the call will block or not (for example, by coupling	823	caller decide whether the call will block or not (for example, by coupling
675	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
676	callbacks so the caller knows that getting the result will not block,	825	callbacks so the caller knows that getting the result will not block,
677	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
678		827
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	828	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	829	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	830	time). This will work even when the event loop does not support blocking
693	waits otherwise.	831	waits otherwise.
694		832
…		…
700	=item $cb = $cv->cb ($cb->($cv))	838	=item $cb = $cv->cb ($cb->($cv))
701		839
702	This is a mutator function that returns the callback set and optionally	840	This is a mutator function that returns the callback set and optionally
703	replaces it before doing so.	841	replaces it before doing so.
704		842
705	The callback will be called when the condition becomes "true", i.e. when	843	The callback will be called when the condition becomes (or already was)
706	C<send> or C<croak> are called, with the only argument being the condition	844	"true", i.e. when C<send> or C<croak> are called (or were called), with
707	variable itself. Calling C<recv> inside the callback or at any later time	845	the only argument being the condition variable itself. Calling C<recv>
708	is guaranteed not to block.	846	inside the callback or at any later time is guaranteed not to block.
709		847
710	=back	848	=back
711		849
		850	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		851
		852	The available backend classes are (every class has its own manpage):
		853
		854	=over 4
		855
		856	=item Backends that are autoprobed when no other event loop can be found.
		857
		858	EV is the preferred backend when no other event loop seems to be in
		859	use. If EV is not installed, then AnyEvent will fall back to its own
		860	pure-perl implementation, which is available everywhere as it comes with
		861	AnyEvent itself.
		862
		863	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		864	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		865
		866	=item Backends that are transparently being picked up when they are used.
		867
		868	These will be used when they are currently loaded when the first watcher
		869	is created, in which case it is assumed that the application is using
		870	them. This means that AnyEvent will automatically pick the right backend
		871	when the main program loads an event module before anything starts to
		872	create watchers. Nothing special needs to be done by the main program.
		873
		874	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		875	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		876	AnyEvent::Impl::Tk based on Tk, very broken.
		877	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		878	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		879	AnyEvent::Impl::Irssi used when running within irssi.
		880
		881	=item Backends with special needs.
		882
		883	Qt requires the Qt::Application to be instantiated first, but will
		884	otherwise be picked up automatically. As long as the main program
		885	instantiates the application before any AnyEvent watchers are created,
		886	everything should just work.
		887
		888	AnyEvent::Impl::Qt based on Qt.
		889
		890	Support for IO::Async can only be partial, as it is too broken and
		891	architecturally limited to even support the AnyEvent API. It also
		892	is the only event loop that needs the loop to be set explicitly, so
		893	it can only be used by a main program knowing about AnyEvent. See
		894	L<AnyEvent::Impl::Async> for the gory details.
		895
		896	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		897
		898	=item Event loops that are indirectly supported via other backends.
		899
		900	Some event loops can be supported via other modules:
		901
		902	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		903
		904	B<WxWidgets> has no support for watching file handles. However, you can
		905	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		906	polls 20 times per second, which was considered to be too horrible to even
		907	consider for AnyEvent.
		908
		909	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		910	backend, so it can be supported through POE.
		911
		912	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		913	load L<POE> when detecting them, in the hope that POE will pick them up,
		914	in which case everything will be automatic.
		915
		916	=back
		917
712	=head1 GLOBAL VARIABLES AND FUNCTIONS	918	=head1 GLOBAL VARIABLES AND FUNCTIONS
713		919
		920	These are not normally required to use AnyEvent, but can be useful to
		921	write AnyEvent extension modules.
		922
714	=over 4	923	=over 4
715		924
716	=item $AnyEvent::MODEL	925	=item $AnyEvent::MODEL
717		926
718	Contains C<undef> until the first watcher is being created. Then it	927	Contains C<undef> until the first watcher is being created, before the
		928	backend has been autodetected.
		929
719	contains the event model that is being used, which is the name of the	930	Afterwards it contains the event model that is being used, which is the
720	Perl class implementing the model. This class is usually one of the	931	name of the Perl class implementing the model. This class is usually one
721	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	932	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
722	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	933	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
723		934	will be C<urxvt::anyevent>).
724	The known classes so far are:
725
726	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
727	AnyEvent::Impl::Event based on Event, second best choice.
728	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
729	AnyEvent::Impl::Glib based on Glib, third-best choice.
730	AnyEvent::Impl::Tk based on Tk, very bad choice.
731	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
732	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
733	AnyEvent::Impl::POE based on POE, not generic enough for full support.
734
735	There is no support for WxWidgets, as WxWidgets has no support for
736	watching file handles. However, you can use WxWidgets through the
737	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
738	second, which was considered to be too horrible to even consider for
739	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
740	it's adaptor.
741
742	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
743	autodetecting them.
744		935
745	=item AnyEvent::detect	936	=item AnyEvent::detect
746		937
747	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	938	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
748	if necessary. You should only call this function right before you would	939	if necessary. You should only call this function right before you would
749	have created an AnyEvent watcher anyway, that is, as late as possible at	940	have created an AnyEvent watcher anyway, that is, as late as possible at
750	runtime.	941	runtime, and not e.g. while initialising of your module.
		942
		943	If you need to do some initialisation before AnyEvent watchers are
		944	created, use C<post_detect>.
751		945
752	=item $guard = AnyEvent::post_detect { BLOCK }	946	=item $guard = AnyEvent::post_detect { BLOCK }
753		947
754	Arranges for the code block to be executed as soon as the event model is	948	Arranges for the code block to be executed as soon as the event model is
755	autodetected (or immediately if this has already happened).	949	autodetected (or immediately if this has already happened).
756		950
		951	The block will be executed I<after> the actual backend has been detected
		952	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		953	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		954	other initialisations - see the sources of L<AnyEvent::Strict> or
		955	L<AnyEvent::AIO> to see how this is used.
		956
		957	The most common usage is to create some global watchers, without forcing
		958	event module detection too early, for example, L<AnyEvent::AIO> creates
		959	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		960	avoid autodetecting the event module at load time.
		961
757	If called in scalar or list context, then it creates and returns an object	962	If called in scalar or list context, then it creates and returns an object
758	that automatically removes the callback again when it is destroyed. See	963	that automatically removes the callback again when it is destroyed (or
		964	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
759	L<Coro::BDB> for a case where this is useful.	965	a case where this is useful.
		966
		967	Example: Create a watcher for the IO::AIO module and store it in
		968	C<$WATCHER>. Only do so after the event loop is initialised, though.
		969
		970	our WATCHER;
		971
		972	my $guard = AnyEvent::post_detect {
		973	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		974	};
		975
		976	# the ||= is important in case post_detect immediately runs the block,
		977	# as to not clobber the newly-created watcher. assigning both watcher and
		978	# post_detect guard to the same variable has the advantage of users being
		979	# able to just C<undef $WATCHER> if the watcher causes them grief.
		980
		981	$WATCHER ||= $guard;
760		982
761	=item @AnyEvent::post_detect	983	=item @AnyEvent::post_detect
762		984
763	If there are any code references in this array (you can C<push> to it	985	If there are any code references in this array (you can C<push> to it
764	before or after loading AnyEvent), then they will called directly after	986	before or after loading AnyEvent), then they will called directly after
765	the event loop has been chosen.	987	the event loop has been chosen.
766		988
767	You should check C<$AnyEvent::MODEL> before adding to this array, though:	989	You should check C<$AnyEvent::MODEL> before adding to this array, though:
768	if it contains a true value then the event loop has already been detected,	990	if it is defined then the event loop has already been detected, and the
769	and the array will be ignored.	991	array will be ignored.
770		992
771	Best use C<AnyEvent::post_detect { BLOCK }> instead.	993	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		994	it, as it takes care of these details.
		995
		996	This variable is mainly useful for modules that can do something useful
		997	when AnyEvent is used and thus want to know when it is initialised, but do
		998	not need to even load it by default. This array provides the means to hook
		999	into AnyEvent passively, without loading it.
		1000
		1001	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1002	together, you could put this into Coro (this is the actual code used by
		1003	Coro to accomplish this):
		1004
		1005	if (defined $AnyEvent::MODEL) {
		1006	# AnyEvent already initialised, so load Coro::AnyEvent
		1007	require Coro::AnyEvent;
		1008	} else {
		1009	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1010	# as soon as it is
		1011	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1012	}
772		1013
773	=back	1014	=back
774		1015
775	=head1 WHAT TO DO IN A MODULE	1016	=head1 WHAT TO DO IN A MODULE
776		1017
…		…
831		1072
832		1073
833	=head1 OTHER MODULES	1074	=head1 OTHER MODULES
834		1075
835	The following is a non-exhaustive list of additional modules that use	1076	The following is a non-exhaustive list of additional modules that use
836	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1077	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
837	in the same program. Some of the modules come with AnyEvent, some are	1078	modules and other event loops in the same program. Some of the modules
838	available via CPAN.	1079	come as part of AnyEvent, the others are available via CPAN.
839		1080
840	=over 4	1081	=over 4
841		1082
842	=item L<AnyEvent::Util>	1083	=item L<AnyEvent::Util>
843		1084
…		…
852		1093
853	=item L<AnyEvent::Handle>	1094	=item L<AnyEvent::Handle>
854		1095
855	Provide read and write buffers, manages watchers for reads and writes,	1096	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	1097	supports raw and formatted I/O, I/O queued and fully transparent and
857	non-blocking SSL/TLS.	1098	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
858		1099
859	=item L<AnyEvent::DNS>	1100	=item L<AnyEvent::DNS>
860		1101
861	Provides rich asynchronous DNS resolver capabilities.	1102	Provides rich asynchronous DNS resolver capabilities.
862		1103
		1104	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1105
		1106	Implement event-based interfaces to the protocols of the same name (for
		1107	the curious, IGS is the International Go Server and FCP is the Freenet
		1108	Client Protocol).
		1109
		1110	=item L<AnyEvent::Handle::UDP>
		1111
		1112	Here be danger!
		1113
		1114	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1115	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1116	it's use of a stream-based API with a protocol that isn't streamable, that
		1117	the only way to improve it is to delete it.
		1118
		1119	It features data corruption (but typically only under load) and general
		1120	confusion. On top, the author is not only clueless about UDP but also
		1121	fact-resistant - some gems of his understanding: "connect doesn't work
		1122	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1123	packets", "I don't need to implement proper error checking as UDP doesn't
		1124	support error checking" and so on - he doesn't even understand what's
		1125	wrong with his module when it is explained to him.
		1126
863	=item L<AnyEvent::HTTP>	1127	=item L<AnyEvent::DBI>
864		1128
865	A simple-to-use HTTP library that is capable of making a lot of concurrent	1129	Executes L<DBI> requests asynchronously in a proxy process for you,
866	HTTP requests.	1130	notifying you in an event-bnased way when the operation is finished.
		1131
		1132	=item L<AnyEvent::AIO>
		1133
		1134	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1135	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1136	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1137	file I/O, and much more.
867		1138
868	=item L<AnyEvent::HTTPD>	1139	=item L<AnyEvent::HTTPD>
869		1140
870	Provides a simple web application server framework.	1141	A simple embedded webserver.
871		1142
872	=item L<AnyEvent::FastPing>	1143	=item L<AnyEvent::FastPing>
873		1144
874	The fastest ping in the west.	1145	The fastest ping in the west.
875		1146
876	=item L<AnyEvent::DBI>
877
878	Executes L<DBI> requests asynchronously in a proxy process.
879
880	=item L<AnyEvent::AIO>
881
882	Truly asynchronous I/O, should be in the toolbox of every event
883	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
884	together.
885
886	=item L<AnyEvent::BDB>
887
888	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
889	L<BDB> and AnyEvent together.
890
891	=item L<AnyEvent::GPSD>
892
893	A non-blocking interface to gpsd, a daemon delivering GPS information.
894
895	=item L<AnyEvent::IGS>
896
897	A non-blocking interface to the Internet Go Server protocol (used by
898	L<App::IGS>).
899
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>
909
910	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
911	of AnyEvent.
912
913	=item L<Event::ExecFlow>
914
915	High level API for event-based execution flow control.
916
917	=item L<Coro>	1147	=item L<Coro>
918		1148
919	Has special support for AnyEvent via L<Coro::AnyEvent>.	1149	Has special support for AnyEvent via L<Coro::AnyEvent>.
920		1150
921	=item L<IO::Lambda>
922
923	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
924
925	=back	1151	=back
926		1152
927	=cut	1153	=cut
928		1154
929	package AnyEvent;	1155	package AnyEvent;
930		1156
931	no warnings;	1157	# basically a tuned-down version of common::sense
932	use strict qw(vars subs);	1158	sub common_sense {
		1159	# from common:.sense 1.0
		1160	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
		1161	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1162	$^H |= 0x00000600;
		1163	}
933		1164
		1165	BEGIN { AnyEvent::common_sense }
		1166
934	use Carp;	1167	use Carp ();
935		1168
936	our $VERSION = 4.412;	1169	our $VERSION = '5.271';
937	our $MODEL;	1170	our $MODEL;
938		1171
939	our $AUTOLOAD;	1172	our $AUTOLOAD;
940	our @ISA;	1173	our @ISA;
941		1174
942	our @REGISTRY;	1175	our @REGISTRY;
943		1176
944	our $WIN32;	1177	our $VERBOSE;
945		1178
946	BEGIN {	1179	BEGIN {
947	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1180	require "AnyEvent/constants.pl";
		1181
948	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1182	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
949		1183
950	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1184	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
951	if ${^TAINT};	1185	if ${^TAINT};
952	}
953		1186
954	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1187	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1188
		1189	}
		1190
		1191	our $MAX_SIGNAL_LATENCY = 10;
955		1192
956	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1193	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
957		1194
958	{	1195	{
959	my $idx;	1196	my $idx;
…		…
961	for reverse split /\s*,\s*/,	1198	for reverse split /\s*,\s*/,
962	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1199	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
963	}	1200	}
964		1201
965	my @models = (	1202	my @models = (
966	[EV:: => AnyEvent::Impl::EV::],	1203	[EV:: => AnyEvent::Impl::EV:: , 1],
967	[Event:: => AnyEvent::Impl::Event::],
968	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1204	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
969	# everything below here will not be autoprobed	1205	# everything below here will not (normally) be autoprobed
970	# as the pureperl backend should work everywhere	1206	# as the pureperl backend should work everywhere
971	# and is usually faster	1207	# and is usually faster
		1208	[Event:: => AnyEvent::Impl::Event::, 1],
		1209	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1210	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1211	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
972	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1212	[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	1213	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
976	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1214	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
977	[Wx:: => AnyEvent::Impl::POE::],	1215	[Wx:: => AnyEvent::Impl::POE::],
978	[Prima:: => AnyEvent::Impl::POE::],	1216	[Prima:: => AnyEvent::Impl::POE::],
		1217	# IO::Async is just too broken - we would need workarounds for its
		1218	# byzantine signal and broken child handling, among others.
		1219	# IO::Async is rather hard to detect, as it doesn't have any
		1220	# obvious default class.
		1221	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1222	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1223	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1224	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
979	);	1225	);
980		1226
981	our %method = map +($_ => 1),	1227	our %method = map +($_ => 1),
982	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1228	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
983		1229
984	our @post_detect;	1230	our @post_detect;
985		1231
986	sub post_detect(&) {	1232	sub post_detect(&) {
987	my ($cb) = @_;	1233	my ($cb) = @_;
988		1234
989	if ($MODEL) {
990	$cb->();
991
992	1
993	} else {
994	push @post_detect, $cb;	1235	push @post_detect, $cb;
995		1236
996	defined wantarray	1237	defined wantarray
997	? bless \$cb, "AnyEvent::Util::postdetect"	1238	? bless \$cb, "AnyEvent::Util::postdetect"
998	: ()	1239	: ()
999	}
1000	}	1240	}
1001		1241
1002	sub AnyEvent::Util::postdetect::DESTROY {	1242	sub AnyEvent::Util::postdetect::DESTROY {
1003	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1243	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1004	}	1244	}
1005		1245
1006	sub detect() {	1246	sub detect() {
		1247	# free some memory
		1248	*detect = sub () { $MODEL };
		1249
		1250	local $!; # for good measure
		1251	local $SIG{__DIE__};
		1252
		1253	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1254	my $model = "AnyEvent::Impl::$1";
		1255	if (eval "require $model") {
		1256	$MODEL = $model;
		1257	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1258	} else {
		1259	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1260	}
		1261	}
		1262
		1263	# check for already loaded models
1007	unless ($MODEL) {	1264	unless ($MODEL) {
1008	no strict 'refs';	1265	for (@REGISTRY, @models) {
1009	local $SIG{__DIE__};	1266	my ($package, $model) = @$_;
1010		1267	if (${"$package\::VERSION"} > 0) {
1011	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1012	my $model = "AnyEvent::Impl::$1";
1013	if (eval "require $model") {	1268	if (eval "require $model") {
1014	$MODEL = $model;	1269	$MODEL = $model;
1015	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1270	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1016	} else {	1271	last;
1017	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1272	}
1018	}	1273	}
1019	}	1274	}
1020		1275
1021	# check for already loaded models
1022	unless ($MODEL) {	1276	unless ($MODEL) {
		1277	# try to autoload a model
1023	for (@REGISTRY, @models) {	1278	for (@REGISTRY, @models) {
1024	my ($package, $model) = @$_;	1279	my ($package, $model, $autoload) = @$_;
		1280	if (
		1281	$autoload
		1282	and eval "require $package"
1025	if (${"$package\::VERSION"} > 0) {	1283	and ${"$package\::VERSION"} > 0
1026	if (eval "require $model") {	1284	and eval "require $model"
		1285	) {
1027	$MODEL = $model;	1286	$MODEL = $model;
1028	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1287	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1029	last;	1288	last;
1030	}
1031	}	1289	}
1032	}	1290	}
1033		1291
1034	unless ($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	1292	$MODEL
1049	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1293	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
1050	}
1051	}	1294	}
1052
1053	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1054
1055	unshift @ISA, $MODEL;
1056
1057	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1058
1059	(shift @post_detect)->() while @post_detect;
1060	}	1295	}
		1296
		1297	@models = (); # free probe data
		1298
		1299	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1300	unshift @ISA, $MODEL;
		1301
		1302	# now nuke some methods that are overriden by the backend.
		1303	# SUPER is not allowed.
		1304	for (qw(time signal child idle)) {
		1305	undef &{"AnyEvent::Base::$_"}
		1306	if defined &{"$MODEL\::$_"};
		1307	}
		1308
		1309	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1310
		1311	(shift @post_detect)->() while @post_detect;
		1312
		1313	*post_detect = sub(&) {
		1314	shift->();
		1315
		1316	undef
		1317	};
1061		1318
1062	$MODEL	1319	$MODEL
1063	}	1320	}
1064		1321
1065	sub AUTOLOAD {	1322	sub AUTOLOAD {
1066	(my $func = $AUTOLOAD) =~ s/.*://;	1323	(my $func = $AUTOLOAD) =~ s/.*://;
1067		1324
1068	$method{$func}	1325	$method{$func}
1069	or croak "$func: not a valid method for AnyEvent objects";	1326	or Carp::croak "$func: not a valid AnyEvent class method";
1070		1327
1071	detect unless $MODEL;	1328	detect;
1072		1329
1073	my $class = shift;	1330	my $class = shift;
1074	$class->$func (@_);	1331	$class->$func (@_);
1075	}	1332	}
1076		1333
1077	# utility function to dup a filehandle. this is used by many backends	1334	# utility function to dup a filehandle. this is used by many backends
1078	# to support binding more than one watcher per filehandle (they usually	1335	# 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).	1336	# allow only one watcher per fd, so we dup it to get a different one).
1080	sub _dupfh($$$$) {	1337	sub _dupfh($$;$$) {
1081	my ($poll, $fh, $r, $w) = @_;	1338	my ($poll, $fh, $r, $w) = @_;
1082		1339
1083	# cygwin requires the fh mode to be matching, unix doesn't	1340	# cygwin requires the fh mode to be matching, unix doesn't
1084	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1341	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1085	: $poll eq "w" ? ($w, ">")
1086	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1087		1342
1088	open my $fh2, "$mode&" . fileno $fh	1343	open my $fh2, $mode, $fh
1089	or die "cannot dup() filehandle: $!,";	1344	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1090		1345
1091	# we assume CLOEXEC is already set by perl in all important cases	1346	# we assume CLOEXEC is already set by perl in all important cases
1092		1347
1093	($fh2, $rw)	1348	($fh2, $rw)
1094	}	1349	}
1095		1350
		1351	=head1 SIMPLIFIED AE API
		1352
		1353	Starting with version 5.0, AnyEvent officially supports a second, much
		1354	simpler, API that is designed to reduce the calling, typing and memory
		1355	overhead by using function call syntax and a fixed number of parameters.
		1356
		1357	See the L<AE> manpage for details.
		1358
		1359	=cut
		1360
		1361	package AE;
		1362
		1363	our $VERSION = $AnyEvent::VERSION;
		1364
		1365	# fall back to the main API by default - backends and AnyEvent::Base
		1366	# implementations can overwrite these.
		1367
		1368	sub io($$$) {
		1369	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1370	}
		1371
		1372	sub timer($$$) {
		1373	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1374	}
		1375
		1376	sub signal($$) {
		1377	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1378	}
		1379
		1380	sub child($$) {
		1381	AnyEvent->child (pid => $_[0], cb => $_[1])
		1382	}
		1383
		1384	sub idle($) {
		1385	AnyEvent->idle (cb => $_[0])
		1386	}
		1387
		1388	sub cv(;&) {
		1389	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1390	}
		1391
		1392	sub now() {
		1393	AnyEvent->now
		1394	}
		1395
		1396	sub now_update() {
		1397	AnyEvent->now_update
		1398	}
		1399
		1400	sub time() {
		1401	AnyEvent->time
		1402	}
		1403
1096	package AnyEvent::Base;	1404	package AnyEvent::Base;
1097		1405
1098	# default implementations for many methods	1406	# default implementations for many methods
1099		1407
1100	BEGIN {	1408	sub time {
		1409	eval q{ # poor man's autoloading {}
		1410	# probe for availability of Time::HiRes
1101	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1411	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1412	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1102	*_time = \&Time::HiRes::time;	1413	*AE::time = \&Time::HiRes::time;
1103	# if (eval "use POSIX (); (POSIX::times())...	1414	# if (eval "use POSIX (); (POSIX::times())...
1104	} else {	1415	} else {
		1416	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1105	*_time = sub { time }; # epic fail	1417	*AE::time = sub (){ time }; # epic fail
		1418	}
		1419
		1420	*time = sub { AE::time }; # different prototypes
		1421	};
		1422	die if $@;
		1423
		1424	&time
		1425	}
		1426
		1427	*now = \&time;
		1428
		1429	sub now_update { }
		1430
		1431	# default implementation for ->condvar
		1432
		1433	sub condvar {
		1434	eval q{ # poor man's autoloading {}
		1435	*condvar = sub {
		1436	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1437	};
		1438
		1439	*AE::cv = sub (;&) {
		1440	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1441	};
		1442	};
		1443	die if $@;
		1444
		1445	&condvar
		1446	}
		1447
		1448	# default implementation for ->signal
		1449
		1450	our $HAVE_ASYNC_INTERRUPT;
		1451
		1452	sub _have_async_interrupt() {
		1453	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1454	&& eval "use Async::Interrupt 1.02 (); 1")
		1455	unless defined $HAVE_ASYNC_INTERRUPT;
		1456
		1457	$HAVE_ASYNC_INTERRUPT
		1458	}
		1459
		1460	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1461	our (%SIG_ASY, %SIG_ASY_W);
		1462	our ($SIG_COUNT, $SIG_TW);
		1463
		1464	# install a dummy wakeup watcher to reduce signal catching latency
		1465	# used by Impls
		1466	sub _sig_add() {
		1467	unless ($SIG_COUNT++) {
		1468	# try to align timer on a full-second boundary, if possible
		1469	my $NOW = AE::now;
		1470
		1471	$SIG_TW = AE::timer
		1472	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1473	$MAX_SIGNAL_LATENCY,
		1474	sub { } # just for the PERL_ASYNC_CHECK
		1475	;
1106	}	1476	}
1107	}	1477	}
1108		1478
1109	sub time { _time }	1479	sub _sig_del {
1110	sub now { _time }	1480	undef $SIG_TW
1111	sub now_update { }	1481	unless --$SIG_COUNT;
1112
1113	# default implementation for ->condvar
1114
1115	sub condvar {
1116	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1117	}	1482	}
1118		1483
1119	# default implementation for ->signal	1484	our $_sig_name_init; $_sig_name_init = sub {
		1485	eval q{ # poor man's autoloading {}
		1486	undef $_sig_name_init;
1120		1487
1121	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1488	if (_have_async_interrupt) {
		1489	*sig2num = \&Async::Interrupt::sig2num;
		1490	*sig2name = \&Async::Interrupt::sig2name;
		1491	} else {
		1492	require Config;
1122		1493
1123	sub _signal_exec {	1494	my %signame2num;
1124	sysread $SIGPIPE_R, my $dummy, 4;	1495	@signame2num{ split ' ', $Config::Config{sig_name} }
		1496	= split ' ', $Config::Config{sig_num};
1125		1497
1126	while (%SIG_EV) {	1498	my @signum2name;
1127	for (keys %SIG_EV) {	1499	@signum2name[values %signame2num] = keys %signame2num;
1128	delete $SIG_EV{$_};	1500
1129	$_->() for values %{ $SIG_CB{$_} || {} };	1501	*sig2num = sub($) {
		1502	$_[0] > 0 ? shift : $signame2num{+shift}
		1503	};
		1504	*sig2name = sub ($) {
		1505	$_[0] > 0 ? $signum2name[+shift] : shift
		1506	};
1130	}	1507	}
1131	}	1508	};
1132	}	1509	die if $@;
		1510	};
		1511
		1512	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1513	sub sig2name($) { &$_sig_name_init; &sig2name }
1133		1514
1134	sub signal {	1515	sub signal {
1135	my (undef, %arg) = @_;	1516	eval q{ # poor man's autoloading {}
		1517	# probe for availability of Async::Interrupt
		1518	if (_have_async_interrupt) {
		1519	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1136		1520
1137	unless ($SIGPIPE_R) {	1521	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1138	require Fcntl;	1522	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1139		1523
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 {	1524	} else {
		1525	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1526
		1527	if (AnyEvent::WIN32) {
		1528	require AnyEvent::Util;
		1529
		1530	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1531	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1532	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1533	} else {
1147	pipe $SIGPIPE_R, $SIGPIPE_W;	1534	pipe $SIGPIPE_R, $SIGPIPE_W;
1148	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1535	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1149	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1536	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1150		1537
1151	# not strictly required, as $^F is normally 2, but let's make sure...	1538	# not strictly required, as $^F is normally 2, but let's make sure...
1152	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1539	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1153	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1540	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1541	}
		1542
		1543	$SIGPIPE_R
		1544	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1545
		1546	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1154	}	1547	}
1155		1548
1156	$SIGPIPE_R	1549	*signal = $HAVE_ASYNC_INTERRUPT
1157	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1550	? sub {
		1551	my (undef, %arg) = @_;
1158		1552
1159	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1553	# async::interrupt
1160	}
1161
1162	my $signal = uc $arg{signal}	1554	my $signal = sig2num $arg{signal};
1163	or Carp::croak "required option 'signal' is missing";
1164
1165	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1555	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1556
		1557	$SIG_ASY{$signal} ||= new Async::Interrupt
		1558	cb => sub { undef $SIG_EV{$signal} },
		1559	signal => $signal,
		1560	pipe => [$SIGPIPE_R->filenos],
		1561	pipe_autodrain => 0,
		1562	;
		1563
		1564	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1565	}
		1566	: sub {
		1567	my (undef, %arg) = @_;
		1568
		1569	# pure perl
		1570	my $signal = sig2name $arg{signal};
		1571	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1572
1166	$SIG{$signal} ||= sub {	1573	$SIG{$signal} ||= sub {
1167	local $!;	1574	local $!;
1168	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1575	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1169	undef $SIG_EV{$signal};	1576	undef $SIG_EV{$signal};
		1577	};
		1578
		1579	# can't do signal processing without introducing races in pure perl,
		1580	# so limit the signal latency.
		1581	_sig_add;
		1582
		1583	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1584	}
		1585	;
		1586
		1587	*AnyEvent::Base::signal::DESTROY = sub {
		1588	my ($signal, $cb) = @{$_[0]};
		1589
		1590	_sig_del;
		1591
		1592	delete $SIG_CB{$signal}{$cb};
		1593
		1594	$HAVE_ASYNC_INTERRUPT
		1595	? delete $SIG_ASY{$signal}
		1596	: # delete doesn't work with older perls - they then
		1597	# print weird messages, or just unconditionally exit
		1598	# instead of getting the default action.
		1599	undef $SIG{$signal}
		1600	unless keys %{ $SIG_CB{$signal} };
		1601	};
		1602
		1603	*_signal_exec = sub {
		1604	$HAVE_ASYNC_INTERRUPT
		1605	? $SIGPIPE_R->drain
		1606	: sysread $SIGPIPE_R, (my $dummy), 9;
		1607
		1608	while (%SIG_EV) {
		1609	for (keys %SIG_EV) {
		1610	delete $SIG_EV{$_};
		1611	$_->() for values %{ $SIG_CB{$_} || {} };
		1612	}
		1613	}
		1614	};
1170	};	1615	};
		1616	die if $@;
1171		1617
1172	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1618	&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	}	1619	}
1185		1620
1186	# default implementation for ->child	1621	# default implementation for ->child
1187		1622
1188	our %PID_CB;	1623	our %PID_CB;
1189	our $CHLD_W;	1624	our $CHLD_W;
1190	our $CHLD_DELAY_W;	1625	our $CHLD_DELAY_W;
1191	our $WNOHANG;	1626	our $WNOHANG;
1192		1627
1193	sub _sigchld {	1628	# used by many Impl's
1194	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1629	sub _emit_childstatus($$) {
		1630	my (undef, $rpid, $rstatus) = @_;
		1631
		1632	$_->($rpid, $rstatus)
1195	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1633	for values %{ $PID_CB{$rpid} || {} },
1196	(values %{ $PID_CB{0} || {} });	1634	values %{ $PID_CB{0} || {} };
1197	}
1198	}	1635	}
1199		1636
1200	sub child {	1637	sub child {
		1638	eval q{ # poor man's autoloading {}
		1639	*_sigchld = sub {
		1640	my $pid;
		1641
		1642	AnyEvent->_emit_childstatus ($pid, $?)
		1643	while ($pid = waitpid -1, $WNOHANG) > 0;
		1644	};
		1645
		1646	*child = sub {
1201	my (undef, %arg) = @_;	1647	my (undef, %arg) = @_;
1202		1648
1203	defined (my $pid = $arg{pid} + 0)	1649	defined (my $pid = $arg{pid} + 0)
1204	or Carp::croak "required option 'pid' is missing";	1650	or Carp::croak "required option 'pid' is missing";
1205		1651
1206	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1652	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1207		1653
		1654	# WNOHANG is almost cetrainly 1 everywhere
		1655	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1656	? 1
1208	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1657	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1209		1658
1210	unless ($CHLD_W) {	1659	unless ($CHLD_W) {
1211	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1660	$CHLD_W = AE::signal CHLD => \&_sigchld;
1212	# child could be a zombie already, so make at least one round	1661	# child could be a zombie already, so make at least one round
1213	&_sigchld;	1662	&_sigchld;
1214	}	1663	}
1215		1664
1216	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1665	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1217	}	1666	};
1218		1667
1219	sub AnyEvent::Base::child::DESTROY {	1668	*AnyEvent::Base::child::DESTROY = sub {
1220	my ($pid, $cb) = @{$_[0]};	1669	my ($pid, $cb) = @{$_[0]};
1221		1670
1222	delete $PID_CB{$pid}{$cb};	1671	delete $PID_CB{$pid}{$cb};
1223	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1672	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1224		1673
1225	undef $CHLD_W unless keys %PID_CB;	1674	undef $CHLD_W unless keys %PID_CB;
		1675	};
		1676	};
		1677	die if $@;
		1678
		1679	&child
1226	}	1680	}
1227		1681
1228	# idle emulation is done by simply using a timer, regardless	1682	# idle emulation is done by simply using a timer, regardless
1229	# of whether the process is idle or not, and not letting	1683	# of whether the process is idle or not, and not letting
1230	# the callback use more than 50% of the time.	1684	# the callback use more than 50% of the time.
1231	sub idle {	1685	sub idle {
		1686	eval q{ # poor man's autoloading {}
		1687	*idle = sub {
1232	my (undef, %arg) = @_;	1688	my (undef, %arg) = @_;
1233		1689
1234	my ($cb, $w, $rcb) = $arg{cb};	1690	my ($cb, $w, $rcb) = $arg{cb};
1235		1691
1236	$rcb = sub {	1692	$rcb = sub {
1237	if ($cb) {	1693	if ($cb) {
1238	$w = _time;	1694	$w = _time;
1239	&$cb;	1695	&$cb;
1240	$w = _time - $w;	1696	$w = _time - $w;
1241		1697
1242	# never use more then 50% of the time for the idle watcher,	1698	# never use more then 50% of the time for the idle watcher,
1243	# within some limits	1699	# within some limits
1244	$w = 0.0001 if $w < 0.0001;	1700	$w = 0.0001 if $w < 0.0001;
1245	$w = 5 if $w > 5;	1701	$w = 5 if $w > 5;
1246		1702
1247	$w = AnyEvent->timer (after => $w, cb => $rcb);	1703	$w = AE::timer $w, 0, $rcb;
1248	} else {	1704	} else {
1249	# clean up...	1705	# clean up...
1250	undef $w;	1706	undef $w;
1251	undef $rcb;	1707	undef $rcb;
		1708	}
		1709	};
		1710
		1711	$w = AE::timer 0.05, 0, $rcb;
		1712
		1713	bless \\$cb, "AnyEvent::Base::idle"
1252	}	1714	};
		1715
		1716	*AnyEvent::Base::idle::DESTROY = sub {
		1717	undef $${$_[0]};
		1718	};
1253	};	1719	};
		1720	die if $@;
1254		1721
1255	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1722	&idle
1256
1257	bless \\$cb, "AnyEvent::Base::idle"
1258	}
1259
1260	sub AnyEvent::Base::idle::DESTROY {
1261	undef $${$_[0]};
1262	}	1723	}
1263		1724
1264	package AnyEvent::CondVar;	1725	package AnyEvent::CondVar;
1265		1726
1266	our @ISA = AnyEvent::CondVar::Base::;	1727	our @ISA = AnyEvent::CondVar::Base::;
1267		1728
1268	package AnyEvent::CondVar::Base;	1729	package AnyEvent::CondVar::Base;
1269		1730
1270	use overload	1731	#use overload
1271	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1732	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1272	fallback => 1;	1733	# fallback => 1;
		1734
		1735	# save 300+ kilobytes by dirtily hardcoding overloading
		1736	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1737	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1738	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1739	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1740
		1741	our $WAITING;
1273		1742
1274	sub _send {	1743	sub _send {
1275	# nop	1744	# nop
1276	}	1745	}
1277		1746
…		…
1290	sub ready {	1759	sub ready {
1291	$_[0]{_ae_sent}	1760	$_[0]{_ae_sent}
1292	}	1761	}
1293		1762
1294	sub _wait {	1763	sub _wait {
		1764	$WAITING
		1765	and !$_[0]{_ae_sent}
		1766	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1767
		1768	local $WAITING = 1;
1295	AnyEvent->one_event while !$_[0]{_ae_sent};	1769	AnyEvent->one_event while !$_[0]{_ae_sent};
1296	}	1770	}
1297		1771
1298	sub recv {	1772	sub recv {
1299	$_[0]->_wait;	1773	$_[0]->_wait;
…		…
1301	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1775	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1302	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1776	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1303	}	1777	}
1304		1778
1305	sub cb {	1779	sub cb {
1306	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1780	my $cv = shift;
		1781
		1782	@_
		1783	and $cv->{_ae_cb} = shift
		1784	and $cv->{_ae_sent}
		1785	and (delete $cv->{_ae_cb})->($cv);
		1786
1307	$_[0]{_ae_cb}	1787	$cv->{_ae_cb}
1308	}	1788	}
1309		1789
1310	sub begin {	1790	sub begin {
1311	++$_[0]{_ae_counter};	1791	++$_[0]{_ae_counter};
1312	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1792	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1361	C<PERL_ANYEVENT_MODEL>.	1841	C<PERL_ANYEVENT_MODEL>.
1362		1842
1363	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1843	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1364	model it chooses.	1844	model it chooses.
1365		1845
		1846	When set to C<8> or higher, then AnyEvent will report extra information on
		1847	which optional modules it loads and how it implements certain features.
		1848
1366	=item C<PERL_ANYEVENT_STRICT>	1849	=item C<PERL_ANYEVENT_STRICT>
1367		1850
1368	AnyEvent does not do much argument checking by default, as thorough	1851	AnyEvent does not do much argument checking by default, as thorough
1369	argument checking is very costly. Setting this variable to a true value	1852	argument checking is very costly. Setting this variable to a true value
1370	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1853	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1371	check the arguments passed to most method calls. If it finds any problems,	1854	check the arguments passed to most method calls. If it finds any problems,
1372	it will croak.	1855	it will croak.
1373		1856
1374	In other words, enables "strict" mode.	1857	In other words, enables "strict" mode.
1375		1858
1376	Unlike C<use strict>, it is definitely recommended to keep it off in	1859	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1377	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1860	>>, it is definitely recommended to keep it off in production. Keeping
1378	developing programs can be very useful, however.	1861	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1862	can be very useful, however.
1379		1863
1380	=item C<PERL_ANYEVENT_MODEL>	1864	=item C<PERL_ANYEVENT_MODEL>
1381		1865
1382	This can be used to specify the event model to be used by AnyEvent, before	1866	This can be used to specify the event model to be used by AnyEvent, before
1383	auto detection and -probing kicks in. It must be a string consisting	1867	auto detection and -probing kicks in. It must be a string consisting
…		…
1426		1910
1427	=item C<PERL_ANYEVENT_MAX_FORKS>	1911	=item C<PERL_ANYEVENT_MAX_FORKS>
1428		1912
1429	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1913	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1430	will create in parallel.	1914	will create in parallel.
		1915
		1916	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1917
		1918	The default value for the C<max_outstanding> parameter for the default DNS
		1919	resolver - this is the maximum number of parallel DNS requests that are
		1920	sent to the DNS server.
		1921
		1922	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1923
		1924	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1925	configuration) in the default resolver. When set to the empty string, no
		1926	default config will be used.
		1927
		1928	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1929
		1930	When neither C<ca_file> nor C<ca_path> was specified during
		1931	L<AnyEvent::TLS> context creation, and either of these environment
		1932	variables exist, they will be used to specify CA certificate locations
		1933	instead of a system-dependent default.
		1934
		1935	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1936
		1937	When these are set to C<1>, then the respective modules are not
		1938	loaded. Mostly good for testing AnyEvent itself.
1431		1939
1432	=back	1940	=back
1433		1941
1434	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1942	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1435		1943
…		…
1493	warn "read: $input\n"; # output what has been read	2001	warn "read: $input\n"; # output what has been read
1494	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2002	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1495	},	2003	},
1496	);	2004	);
1497		2005
1498	my $time_watcher; # can only be used once
1499
1500	sub new_timer {
1501	$timer = AnyEvent->timer (after => 1, cb => sub {	2006	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1502	warn "timeout\n"; # print 'timeout' about every second	2007	warn "timeout\n"; # print 'timeout' at most every second
1503	&new_timer; # and restart the time
1504	});	2008	});
1505	}
1506
1507	new_timer; # create first timer
1508		2009
1509	$cv->recv; # wait until user enters /^q/i	2010	$cv->recv; # wait until user enters /^q/i
1510		2011
1511	=head1 REAL-WORLD EXAMPLE	2012	=head1 REAL-WORLD EXAMPLE
1512		2013
…		…
1585		2086
1586	The actual code goes further and collects all errors (C<die>s, exceptions)	2087	The actual code goes further and collects all errors (C<die>s, exceptions)
1587	that occurred during request processing. The C<result> method detects	2088	that occurred during request processing. The C<result> method detects
1588	whether an exception as thrown (it is stored inside the $txn object)	2089	whether an exception as thrown (it is stored inside the $txn object)
1589	and just throws the exception, which means connection errors and other	2090	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	2091	problems get reported to the code that tries to use the result, not in a
1591	random callback.	2092	random callback.
1592		2093
1593	All of this enables the following usage styles:	2094	All of this enables the following usage styles:
1594		2095
1595	1. Blocking:	2096	1. Blocking:
…		…
1643	through AnyEvent. The benchmark creates a lot of timers (with a zero	2144	through AnyEvent. The benchmark creates a lot of timers (with a zero
1644	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2145	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1645	which it is), lets them fire exactly once and destroys them again.	2146	which it is), lets them fire exactly once and destroys them again.
1646		2147
1647	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2148	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1648	distribution.	2149	distribution. It uses the L<AE> interface, which makes a real difference
		2150	for the EV and Perl backends only.
1649		2151
1650	=head3 Explanation of the columns	2152	=head3 Explanation of the columns
1651		2153
1652	I<watcher> is the number of event watchers created/destroyed. Since	2154	I<watcher> is the number of event watchers created/destroyed. Since
1653	different event models feature vastly different performances, each event	2155	different event models feature vastly different performances, each event
…		…
1674	watcher.	2176	watcher.
1675		2177
1676	=head3 Results	2178	=head3 Results
1677		2179
1678	name watchers bytes create invoke destroy comment	2180	name watchers bytes create invoke destroy comment
1679	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2181	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1680	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2182	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1681	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2183	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1682	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2184	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1683	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2185	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1684	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2186	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2187	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2188	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	2189	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	2190	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	2191	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	2192	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1689		2193
1690	=head3 Discussion	2194	=head3 Discussion
1691		2195
1692	The benchmark does I<not> measure scalability of the event loop very	2196	The benchmark does I<not> measure scalability of the event loop very
1693	well. For example, a select-based event loop (such as the pure perl one)	2197	well. For example, a select-based event loop (such as the pure perl one)
…		…
1705	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2209	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	2210	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1707	cycles with POE.	2211	cycles with POE.
1708		2212
1709	C<EV> is the sole leader regarding speed and memory use, which are both	2213	C<EV> is the sole leader regarding speed and memory use, which are both
1710	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2214	maximal/minimal, respectively. When using the L<AE> API there is zero
		2215	overhead (when going through the AnyEvent API create is about 5-6 times
		2216	slower, with other times being equal, so still uses far less memory than
1711	far less memory than any other event loop and is still faster than Event	2217	any other event loop and is still faster than Event natively).
1712	natively.
1713		2218
1714	The pure perl implementation is hit in a few sweet spots (both the	2219	The pure perl implementation is hit in a few sweet spots (both the
1715	constant timeout and the use of a single fd hit optimisations in the perl	2220	constant timeout and the use of a single fd hit optimisations in the perl
1716	interpreter and the backend itself). Nevertheless this shows that it	2221	interpreter and the backend itself). Nevertheless this shows that it
1717	adds very little overhead in itself. Like any select-based backend its	2222	adds very little overhead in itself. Like any select-based backend its
1718	performance becomes really bad with lots of file descriptors (and few of	2223	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.	2224	them active), of course, but this was not subject of this benchmark.
1720		2225
1721	The C<Event> module has a relatively high setup and callback invocation	2226	The C<Event> module has a relatively high setup and callback invocation
1722	cost, but overall scores in on the third place.	2227	cost, but overall scores in on the third place.
		2228
		2229	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2230	when using its pure perl backend.
1723		2231
1724	C<Glib>'s memory usage is quite a bit higher, but it features a	2232	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	2233	faster callback invocation and overall ends up in the same class as
1726	C<Event>. However, Glib scales extremely badly, doubling the number of	2234	C<Event>. However, Glib scales extremely badly, doubling the number of
1727	watchers increases the processing time by more than a factor of four,	2235	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	2296	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	2297	(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.	2298	connections, most of which are idle at any one point in time.
1791		2299
1792	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2300	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1793	distribution.	2301	distribution. It uses the L<AE> interface, which makes a real difference
		2302	for the EV and Perl backends only.
1794		2303
1795	=head3 Explanation of the columns	2304	=head3 Explanation of the columns
1796		2305
1797	I<sockets> is the number of sockets, and twice the number of "servers" (as	2306	I<sockets> is the number of sockets, and twice the number of "servers" (as
1798	each server has a read and write socket end).	2307	each server has a read and write socket end).
…		…
1805	it to another server. This includes deleting the old timeout and creating	2314	it to another server. This includes deleting the old timeout and creating
1806	a new one that moves the timeout into the future.	2315	a new one that moves the timeout into the future.
1807		2316
1808	=head3 Results	2317	=head3 Results
1809		2318
1810	name sockets create request	2319	name sockets create request
1811	EV 20000 69.01 11.16	2320	EV 20000 62.66 7.99
1812	Perl 20000 73.32 35.87	2321	Perl 20000 68.32 32.64
1813	Event 20000 212.62 257.32	2322	IOAsync 20000 174.06 101.15 epoll
1814	Glib 20000 651.16 1896.30	2323	IOAsync 20000 174.67 610.84 poll
		2324	Event 20000 202.69 242.91
		2325	Glib 20000 557.01 1689.52
1815	POE 20000 349.67 12317.24 uses POE::Loop::Event	2326	POE 20000 341.54 12086.32 uses POE::Loop::Event
1816		2327
1817	=head3 Discussion	2328	=head3 Discussion
1818		2329
1819	This benchmark I<does> measure scalability and overall performance of the	2330	This benchmark I<does> measure scalability and overall performance of the
1820	particular event loop.	2331	particular event loop.
…		…
1822	EV is again fastest. Since it is using epoll on my system, the setup time	2333	EV is again fastest. Since it is using epoll on my system, the setup time
1823	is relatively high, though.	2334	is relatively high, though.
1824		2335
1825	Perl surprisingly comes second. It is much faster than the C-based event	2336	Perl surprisingly comes second. It is much faster than the C-based event
1826	loops Event and Glib.	2337	loops Event and Glib.
		2338
		2339	IO::Async performs very well when using its epoll backend, and still quite
		2340	good compared to Glib when using its pure perl backend.
1827		2341
1828	Event suffers from high setup time as well (look at its code and you will	2342	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	2343	understand why). Callback invocation also has a high overhead compared to
1830	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2344	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1831	uses select or poll in basically all documented configurations.	2345	uses select or poll in basically all documented configurations.
…		…
1943	As you can see, the AnyEvent + EV combination even beats the	2457	As you can see, the AnyEvent + EV combination even beats the
1944	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2458	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
1945	backend easily beats IO::Lambda and POE.	2459	backend easily beats IO::Lambda and POE.
1946		2460
1947	And even the 100% non-blocking version written using the high-level (and	2461	And even the 100% non-blocking version written using the high-level (and
1948	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2462	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
1949	large margin, even though it does all of DNS, tcp-connect and socket I/O	2463	higher level ("unoptimised") abstractions by a large margin, even though
1950	in a non-blocking way.	2464	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
1951		2465
1952	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2466	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
1953	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2467	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
1954	part of the IO::lambda distribution and were used without any changes.	2468	part of the IO::Lambda distribution and were used without any changes.
1955		2469
1956		2470
1957	=head1 SIGNALS	2471	=head1 SIGNALS
1958		2472
1959	AnyEvent currently installs handlers for these signals:	2473	AnyEvent currently installs handlers for these signals:
…		…
1963	=item SIGCHLD	2477	=item SIGCHLD
1964		2478
1965	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2479	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1966	emulation for event loops that do not support them natively. Also, some	2480	emulation for event loops that do not support them natively. Also, some
1967	event loops install a similar handler.	2481	event loops install a similar handler.
		2482
		2483	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2484	AnyEvent will reset it to default, to avoid losing child exit statuses.
1968		2485
1969	=item SIGPIPE	2486	=item SIGPIPE
1970		2487
1971	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2488	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1972	when AnyEvent gets loaded.	2489	when AnyEvent gets loaded.
…		…
1984		2501
1985	=back	2502	=back
1986		2503
1987	=cut	2504	=cut
1988		2505
		2506	undef $SIG{CHLD}
		2507	if $SIG{CHLD} eq 'IGNORE';
		2508
1989	$SIG{PIPE} = sub { }	2509	$SIG{PIPE} = sub { }
1990	unless defined $SIG{PIPE};	2510	unless defined $SIG{PIPE};
1991		2511
		2512	=head1 RECOMMENDED/OPTIONAL MODULES
		2513
		2514	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2515	it's built-in modules) are required to use it.
		2516
		2517	That does not mean that AnyEvent won't take advantage of some additional
		2518	modules if they are installed.
		2519
		2520	This section explains which additional modules will be used, and how they
		2521	affect AnyEvent's operation.
		2522
		2523	=over 4
		2524
		2525	=item L<Async::Interrupt>
		2526
		2527	This slightly arcane module is used to implement fast signal handling: To
		2528	my knowledge, there is no way to do completely race-free and quick
		2529	signal handling in pure perl. To ensure that signals still get
		2530	delivered, AnyEvent will start an interval timer to wake up perl (and
		2531	catch the signals) with some delay (default is 10 seconds, look for
		2532	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2533
		2534	If this module is available, then it will be used to implement signal
		2535	catching, which means that signals will not be delayed, and the event loop
		2536	will not be interrupted regularly, which is more efficient (and good for
		2537	battery life on laptops).
		2538
		2539	This affects not just the pure-perl event loop, but also other event loops
		2540	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2541
		2542	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2543	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2544	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2545	does nothing for those backends.
		2546
		2547	=item L<EV>
		2548
		2549	This module isn't really "optional", as it is simply one of the backend
		2550	event loops that AnyEvent can use. However, it is simply the best event
		2551	loop available in terms of features, speed and stability: It supports
		2552	the AnyEvent API optimally, implements all the watcher types in XS, does
		2553	automatic timer adjustments even when no monotonic clock is available,
		2554	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2555	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2556	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2557
		2558	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2559	then this module will do nothing for you.
		2560
		2561	=item L<Guard>
		2562
		2563	The guard module, when used, will be used to implement
		2564	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2565	lot less memory), but otherwise doesn't affect guard operation much. It is
		2566	purely used for performance.
		2567
		2568	=item L<JSON> and L<JSON::XS>
		2569
		2570	One of these modules is required when you want to read or write JSON data
		2571	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2572	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2573
		2574	=item L<Net::SSLeay>
		2575
		2576	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2577	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2578	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2579
		2580	=item L<Time::HiRes>
		2581
		2582	This module is part of perl since release 5.008. It will be used when the
		2583	chosen event library does not come with a timing source on it's own. The
		2584	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2585	try to use a monotonic clock for timing stability.
		2586
		2587	=back
		2588
1992		2589
1993	=head1 FORK	2590	=head1 FORK
1994		2591
1995	Most event libraries are not fork-safe. The ones who are usually are	2592	Most event libraries are not fork-safe. The ones who are usually are
1996	because they rely on inefficient but fork-safe C<select> or C<poll>	2593	because they rely on inefficient but fork-safe C<select> or C<poll> calls
1997	calls. Only L<EV> is fully fork-aware.	2594	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2595	are usually badly thought-out hacks that are incompatible with fork in
		2596	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2597	continue event-processing in both parent and child (or both, if you know
		2598	what you are doing).
		2599
		2600	This means that, in general, you cannot fork and do event processing in
		2601	the child if the event library was initialised before the fork (which
		2602	usually happens when the first AnyEvent watcher is created, or the library
		2603	is loaded).
1998		2604
1999	If you have to fork, you must either do so I<before> creating your first	2605	If you have to fork, you must either do so I<before> creating your first
2000	watcher OR you must not use AnyEvent at all in the child.	2606	watcher OR you must not use AnyEvent at all in the child OR you must do
		2607	something completely out of the scope of AnyEvent.
		2608
		2609	The problem of doing event processing in the parent I<and> the child
		2610	is much more complicated: even for backends that I<are> fork-aware or
		2611	fork-safe, their behaviour is not usually what you want: fork clones all
		2612	watchers, that means all timers, I/O watchers etc. are active in both
		2613	parent and child, which is almost never what you want. USing C<exec>
		2614	to start worker children from some kind of manage rprocess is usually
		2615	preferred, because it is much easier and cleaner, at the expense of having
		2616	to have another binary.
2001		2617
2002		2618
2003	=head1 SECURITY CONSIDERATIONS	2619	=head1 SECURITY CONSIDERATIONS
2004		2620
2005	AnyEvent can be forced to load any event model via	2621	AnyEvent can be forced to load any event model via
…		…
2043	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2659	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2044		2660
2045	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2661	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2046	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2662	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2047	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2663	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2048	L<AnyEvent::Impl::POE>.	2664	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2049		2665
2050	Non-blocking file handles, sockets, TCP clients and	2666	Non-blocking file handles, sockets, TCP clients and
2051	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2667	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2052		2668
2053	Asynchronous DNS: L<AnyEvent::DNS>.	2669	Asynchronous DNS: L<AnyEvent::DNS>.
2054		2670
2055	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2671	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2672	L<Coro::Event>,
2056		2673
2057	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2674	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2675	L<AnyEvent::HTTP>.
2058		2676
2059		2677
2060	=head1 AUTHOR	2678	=head1 AUTHOR
2061		2679
2062	Marc Lehmann <schmorp@schmorp.de>	2680	Marc Lehmann <schmorp@schmorp.de>

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