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Revision 1.297 by root, Thu Nov 19 01:55:57 2009 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
…		…
40	=head1 INTRODUCTION/TUTORIAL	40	=head1 INTRODUCTION/TUTORIAL
41		41
42	This manpage is mainly a reference manual. If you are interested	42	This manpage is mainly a reference manual. If you are interested
43	in a tutorial or some gentle introduction, have a look at the	43	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	44	L<AnyEvent::Intro> manpage.
		45
		46	=head1 SUPPORT
		47
		48	There is a mailinglist for discussing all things AnyEvent, and an IRC
		49	channel, too.
		50
		51	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		52	Repository>, at L<http://anyevent.schmorp.de>, for more info.
45		53
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	54	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		55
48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	56	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49	nowadays. So what is different about AnyEvent?	57	nowadays. So what is different about AnyEvent?
…		…
173	my variables are only visible after the statement in which they are	181	my variables are only visible after the statement in which they are
174	declared.	182	declared.
175		183
176	=head2 I/O WATCHERS	184	=head2 I/O WATCHERS
177		185
		186	$w = AnyEvent->io (
		187	fh => <filehandle_or_fileno>,
		188	poll => <"r" or "w">,
		189	cb => <callback>,
		190	);
		191
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	192	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	193	with the following mandatory key-value pairs as arguments:
180		194
181	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch	195	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	196	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	197	handle). Note that only file handles pointing to things for which
184	non-blocking operation makes sense are allowed. This includes sockets,	198	non-blocking operation makes sense are allowed. This includes sockets,
185	most character devices, pipes, fifos and so on, but not for example files	199	most character devices, pipes, fifos and so on, but not for example files
186	or block devices.	200	or block devices.
…		…
211	undef $w;	225	undef $w;
212	});	226	});
213		227
214	=head2 TIME WATCHERS	228	=head2 TIME WATCHERS
215		229
		230	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		231
		232	$w = AnyEvent->timer (
		233	after => <fractional_seconds>,
		234	interval => <fractional_seconds>,
		235	cb => <callback>,
		236	);
		237
216	You can create a time watcher by calling the C<< AnyEvent->timer >>	238	You can create a time watcher by calling the C<< AnyEvent->timer >>
217	method with the following mandatory arguments:	239	method with the following mandatory arguments:
218		240
219	C<after> specifies after how many seconds (fractional values are	241	C<after> specifies after how many seconds (fractional values are
220	supported) the callback should be invoked. C<cb> is the callback to invoke	242	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
341	might affect timers and time-outs.	363	might affect timers and time-outs.
342		364
343	When this is the case, you can call this method, which will update the	365	When this is the case, you can call this method, which will update the
344	event loop's idea of "current time".	366	event loop's idea of "current time".
345		367
		368	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		369	when mod_perl executes the script, then the event loop will have the wrong
		370	idea about the "current time" (being potentially far in the past, when the
		371	script ran the last time). In that case you should arrange a call to C<<
		372	AnyEvent->now_update >> each time the web server process wakes up again
		373	(e.g. at the start of your script, or in a handler).
		374
346	Note that updating the time I<might> cause some events to be handled.	375	Note that updating the time I<might> cause some events to be handled.
347		376
348	=back	377	=back
349		378
350	=head2 SIGNAL WATCHERS	379	=head2 SIGNAL WATCHERS
		380
		381	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351		382
352	You can watch for signals using a signal watcher, C<signal> is the signal	383	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	384	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354	callback to be invoked whenever a signal occurs.	385	callback to be invoked whenever a signal occurs.
355		386
…		…
361	invocation, and callback invocation will be synchronous. Synchronous means	392	invocation, and callback invocation will be synchronous. Synchronous means
362	that it might take a while until the signal gets handled by the process,	393	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.	394	but it is guaranteed not to interrupt any other callbacks.
364		395
365	The main advantage of using these watchers is that you can share a signal	396	The main advantage of using these watchers is that you can share a signal
366	between multiple watchers.	397	between multiple watchers, and AnyEvent will ensure that signals will not
		398	interrupt your program at bad times.
367		399
368	This watcher might use C<%SIG>, so programs overwriting those signals	400	This watcher might use C<%SIG> (depending on the event loop used),
369	directly will likely not work correctly.	401	so programs overwriting those signals directly will likely not work
		402	correctly.
370		403
371	Example: exit on SIGINT	404	Example: exit on SIGINT
372		405
373	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	406	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
374		407
		408	=head3 Signal Races, Delays and Workarounds
		409
		410	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		411	callbacks to signals in a generic way, which is a pity, as you cannot
		412	do race-free signal handling in perl, requiring C libraries for
		413	this. AnyEvent will try to do it's best, which means in some cases,
		414	signals will be delayed. The maximum time a signal might be delayed is
		415	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		416	variable can be changed only before the first signal watcher is created,
		417	and should be left alone otherwise. This variable determines how often
		418	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		419	will cause fewer spurious wake-ups, which is better for power and CPU
		420	saving.
		421
		422	All these problems can be avoided by installing the optional
		423	L<Async::Interrupt> module, which works with most event loops. It will not
		424	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		425	(and not with L<POE> currently, as POE does it's own workaround with
		426	one-second latency). For those, you just have to suffer the delays.
		427
375	=head2 CHILD PROCESS WATCHERS	428	=head2 CHILD PROCESS WATCHERS
376		429
		430	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		431
377	You can also watch on a child process exit and catch its exit status.	432	You can also watch on a child process exit and catch its exit status.
378		433
379	The child process is specified by the C<pid> argument (if set to C<0>, it	434	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	435	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	436	croak). The watcher will be triggered only when the child process has
382	any trace events (stopped/continued).	437	finished and an exit status is available, not on any trace events
		438	(stopped/continued).
383		439
384	The callback will be called with the pid and exit status (as returned by	440	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	441	waitpid), so unlike other watcher types, you I<can> rely on child watcher
386	callback arguments.	442	callback arguments.
387		443
…		…
392		448
393	There is a slight catch to child watchers, however: you usually start them	449	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	450	I<after> the child process was created, and this means the process could
395	have exited already (and no SIGCHLD will be sent anymore).	451	have exited already (and no SIGCHLD will be sent anymore).
396		452
397	Not all event models handle this correctly (POE doesn't), but even for	453	Not all event models handle this correctly (neither POE nor IO::Async do,
		454	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	455	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).	456	the process exits (i.e. before you fork in the first place). AnyEvent's
		457	pure perl event loop handles all cases correctly regardless of when you
		458	start the watcher.
400		459
401	This means you cannot create a child watcher as the very first thing in an	460	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	461	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>).	462	watcher before you C<fork> the child (alternatively, you can call
		463	C<AnyEvent::detect>).
		464
		465	As most event loops do not support waiting for child events, they will be
		466	emulated by AnyEvent in most cases, in which the latency and race problems
		467	mentioned in the description of signal watchers apply.
404		468
405	Example: fork a process and wait for it	469	Example: fork a process and wait for it
406		470
407	my $done = AnyEvent->condvar;	471	my $done = AnyEvent->condvar;
408		472
…		…
420	# do something else, then wait for process exit	484	# do something else, then wait for process exit
421	$done->recv;	485	$done->recv;
422		486
423	=head2 IDLE WATCHERS	487	=head2 IDLE WATCHERS
424		488
		489	$w = AnyEvent->idle (cb => <callback>);
		490
425	Sometimes there is a need to do something, but it is not so important	491	Sometimes there is a need to do something, but it is not so important
426	to do it instantly, but only when there is nothing better to do. This	492	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	493	"nothing better to do" is usually defined to be "no other events need
428	attention by the event loop".	494	attention by the event loop".
429		495
…		…
455	});	521	});
456	});	522	});
457		523
458	=head2 CONDITION VARIABLES	524	=head2 CONDITION VARIABLES
459		525
		526	$cv = AnyEvent->condvar;
		527
		528	$cv->send (<list>);
		529	my @res = $cv->recv;
		530
460	If you are familiar with some event loops you will know that all of them	531	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	532	require you to run some blocking "loop", "run" or similar function that
462	will actively watch for new events and call your callbacks.	533	will actively watch for new events and call your callbacks.
463		534
464	AnyEvent is different, it expects somebody else to run the event loop and	535	AnyEvent is slightly different: it expects somebody else to run the event
465	will only block when necessary (usually when told by the user).	536	loop and will only block when necessary (usually when told by the user).
466		537
467	The instrument to do that is called a "condition variable", so called	538	The instrument to do that is called a "condition variable", so called
468	because they represent a condition that must become true.	539	because they represent a condition that must become true.
469		540
		541	Now is probably a good time to look at the examples further below.
		542
470	Condition variables can be created by calling the C<< AnyEvent->condvar	543	Condition variables can be created by calling the C<< AnyEvent->condvar
471	>> method, usually without arguments. The only argument pair allowed is	544	>> 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	545	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	546	becomes true, with the condition variable as the first argument (but not
475	the results).	547	the results).
476		548
477	After creation, the condition variable is "false" until it becomes "true"	549	After creation, the condition variable is "false" until it becomes "true"
…		…
482	Condition variables are similar to callbacks, except that you can	554	Condition variables are similar to callbacks, except that you can
483	optionally wait for them. They can also be called merge points - points	555	optionally wait for them. They can also be called merge points - points
484	in time where multiple outstanding events have been processed. And yet	556	in time where multiple outstanding events have been processed. And yet
485	another way to call them is transactions - each condition variable can be	557	another way to call them is transactions - each condition variable can be
486	used to represent a transaction, which finishes at some point and delivers	558	used to represent a transaction, which finishes at some point and delivers
487	a result.	559	a result. And yet some people know them as "futures" - a promise to
		560	compute/deliver something that you can wait for.
488		561
489	Condition variables are very useful to signal that something has finished,	562	Condition variables are very useful to signal that something has finished,
490	for example, if you write a module that does asynchronous http requests,	563	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	564	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	565	availability of results. The user can either act when the callback is
…		…
526	after => 1,	599	after => 1,
527	cb => sub { $result_ready->send },	600	cb => sub { $result_ready->send },
528	);	601	);
529		602
530	# this "blocks" (while handling events) till the callback	603	# this "blocks" (while handling events) till the callback
531	# calls send	604	# calls ->send
532	$result_ready->recv;	605	$result_ready->recv;
533		606
534	Example: wait for a timer, but take advantage of the fact that	607	Example: wait for a timer, but take advantage of the fact that condition
535	condition variables are also code references.	608	variables are also callable directly.
536		609
537	my $done = AnyEvent->condvar;	610	my $done = AnyEvent->condvar;
538	my $delay = AnyEvent->timer (after => 5, cb => $done);	611	my $delay = AnyEvent->timer (after => 5, cb => $done);
539	$done->recv;	612	$done->recv;
540		613
…		…
546		619
547	...	620	...
548		621
549	my @info = $couchdb->info->recv;	622	my @info = $couchdb->info->recv;
550		623
551	And this is how you would just ste a callback to be called whenever the	624	And this is how you would just set a callback to be called whenever the
552	results are available:	625	results are available:
553		626
554	$couchdb->info->cb (sub {	627	$couchdb->info->cb (sub {
555	my @info = $_[0]->recv;	628	my @info = $_[0]->recv;
556	});	629	});
…		…
574	immediately from within send.	647	immediately from within send.
575		648
576	Any arguments passed to the C<send> call will be returned by all	649	Any arguments passed to the C<send> call will be returned by all
577	future C<< ->recv >> calls.	650	future C<< ->recv >> calls.
578		651
579	Condition variables are overloaded so one can call them directly	652	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	653	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	654	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		655
588	=item $cv->croak ($error)	656	=item $cv->croak ($error)
589		657
590	Similar to send, but causes all call's to C<< ->recv >> to invoke	658	Similar to send, but causes all call's to C<< ->recv >> to invoke
591	C<Carp::croak> with the given error message/object/scalar.	659	C<Carp::croak> with the given error message/object/scalar.
592		660
593	This can be used to signal any errors to the condition variable	661	This can be used to signal any errors to the condition variable
594	user/consumer.	662	user/consumer. Doing it this way instead of calling C<croak> directly
		663	delays the error detetcion, but has the overwhelmign advantage that it
		664	diagnoses the error at the place where the result is expected, and not
		665	deep in some event clalback without connection to the actual code causing
		666	the problem.
595		667
596	=item $cv->begin ([group callback])	668	=item $cv->begin ([group callback])
597		669
598	=item $cv->end	670	=item $cv->end
599
600	These two methods are EXPERIMENTAL and MIGHT CHANGE.
601		671
602	These two methods can be used to combine many transactions/events into	672	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	673	one. For example, a function that pings many hosts in parallel might want
604	to use a condition variable for the whole process.	674	to use a condition variable for the whole process.
605		675
606	Every call to C<< ->begin >> will increment a counter, and every call to	676	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	677	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	678	>>, 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	679	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.	680	>>, but that is not required. If no group callback was set, C<send> will
		681	be called without any arguments.
611		682
612	Let's clarify this with the ping example:	683	You can think of C<< $cv->send >> giving you an OR condition (one call
		684	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		685	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		686
		687	Let's start with a simple example: you have two I/O watchers (for example,
		688	STDOUT and STDERR for a program), and you want to wait for both streams to
		689	close before activating a condvar:
613		690
614	my $cv = AnyEvent->condvar;	691	my $cv = AnyEvent->condvar;
615		692
		693	$cv->begin; # first watcher
		694	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		695	defined sysread $fh1, my $buf, 4096
		696	or $cv->end;
		697	});
		698
		699	$cv->begin; # second watcher
		700	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		701	defined sysread $fh2, my $buf, 4096
		702	or $cv->end;
		703	});
		704
		705	$cv->recv;
		706
		707	This works because for every event source (EOF on file handle), there is
		708	one call to C<begin>, so the condvar waits for all calls to C<end> before
		709	sending.
		710
		711	The ping example mentioned above is slightly more complicated, as the
		712	there are results to be passwd back, and the number of tasks that are
		713	begung can potentially be zero:
		714
		715	my $cv = AnyEvent->condvar;
		716
616	my %result;	717	my %result;
617	$cv->begin (sub { $cv->send (\%result) });	718	$cv->begin (sub { shift->send (\%result) });
618		719
619	for my $host (@list_of_hosts) {	720	for my $host (@list_of_hosts) {
620	$cv->begin;	721	$cv->begin;
621	ping_host_then_call_callback $host, sub {	722	ping_host_then_call_callback $host, sub {
622	$result{$host} = ...;	723	$result{$host} = ...;
…		…
637	loop, which serves two important purposes: first, it sets the callback	738	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	739	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	740	C<send> is called even when C<no> hosts are being pinged (the loop
640	doesn't execute once).	741	doesn't execute once).
641		742
642	This is the general pattern when you "fan out" into multiple subrequests:	743	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>	744	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	745	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>.	746	subrequest you start, call C<begin> and for each subrequest you finish,
		747	call C<end>.
646		748
647	=back	749	=back
648		750
649	=head3 METHODS FOR CONSUMERS	751	=head3 METHODS FOR CONSUMERS
650		752
…		…
666	function will call C<croak>.	768	function will call C<croak>.
667		769
668	In list context, all parameters passed to C<send> will be returned,	770	In list context, all parameters passed to C<send> will be returned,
669	in scalar context only the first one will be returned.	771	in scalar context only the first one will be returned.
670		772
		773	Note that doing a blocking wait in a callback is not supported by any
		774	event loop, that is, recursive invocation of a blocking C<< ->recv
		775	>> is not allowed, and the C<recv> call will C<croak> if such a
		776	condition is detected. This condition can be slightly loosened by using
		777	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		778	any thread that doesn't run the event loop itself.
		779
671	Not all event models support a blocking wait - some die in that case	780	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	781	(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	782	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	783	caller decide whether the call will block or not (for example, by coupling
675	condition variables with some kind of request results and supporting	784	condition variables with some kind of request results and supporting
676	callbacks so the caller knows that getting the result will not block,	785	callbacks so the caller knows that getting the result will not block,
677	while still supporting blocking waits if the caller so desires).	786	while still supporting blocking waits if the caller so desires).
678		787
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	788	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	789	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	790	time). This will work even when the event loop does not support blocking
693	waits otherwise.	791	waits otherwise.
694		792
…		…
700	=item $cb = $cv->cb ($cb->($cv))	798	=item $cb = $cv->cb ($cb->($cv))
701		799
702	This is a mutator function that returns the callback set and optionally	800	This is a mutator function that returns the callback set and optionally
703	replaces it before doing so.	801	replaces it before doing so.
704		802
705	The callback will be called when the condition becomes "true", i.e. when	803	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	804	"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	805	the only argument being the condition variable itself. Calling C<recv>
708	is guaranteed not to block.	806	inside the callback or at any later time is guaranteed not to block.
709		807
710	=back	808	=back
711		809
		810	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		811
		812	The available backend classes are (every class has its own manpage):
		813
		814	=over 4
		815
		816	=item Backends that are autoprobed when no other event loop can be found.
		817
		818	EV is the preferred backend when no other event loop seems to be in
		819	use. If EV is not installed, then AnyEvent will fall back to its own
		820	pure-perl implementation, which is available everywhere as it comes with
		821	AnyEvent itself.
		822
		823	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		824	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		825
		826	=item Backends that are transparently being picked up when they are used.
		827
		828	These will be used when they are currently loaded when the first watcher
		829	is created, in which case it is assumed that the application is using
		830	them. This means that AnyEvent will automatically pick the right backend
		831	when the main program loads an event module before anything starts to
		832	create watchers. Nothing special needs to be done by the main program.
		833
		834	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		835	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		836	AnyEvent::Impl::Tk based on Tk, very broken.
		837	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		838	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		839	AnyEvent::Impl::Irssi used when running within irssi.
		840
		841	=item Backends with special needs.
		842
		843	Qt requires the Qt::Application to be instantiated first, but will
		844	otherwise be picked up automatically. As long as the main program
		845	instantiates the application before any AnyEvent watchers are created,
		846	everything should just work.
		847
		848	AnyEvent::Impl::Qt based on Qt.
		849
		850	Support for IO::Async can only be partial, as it is too broken and
		851	architecturally limited to even support the AnyEvent API. It also
		852	is the only event loop that needs the loop to be set explicitly, so
		853	it can only be used by a main program knowing about AnyEvent. See
		854	L<AnyEvent::Impl::Async> for the gory details.
		855
		856	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		857
		858	=item Event loops that are indirectly supported via other backends.
		859
		860	Some event loops can be supported via other modules:
		861
		862	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		863
		864	B<WxWidgets> has no support for watching file handles. However, you can
		865	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		866	polls 20 times per second, which was considered to be too horrible to even
		867	consider for AnyEvent.
		868
		869	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		870	backend, so it can be supported through POE.
		871
		872	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		873	load L<POE> when detecting them, in the hope that POE will pick them up,
		874	in which case everything will be automatic.
		875
		876	=back
		877
712	=head1 GLOBAL VARIABLES AND FUNCTIONS	878	=head1 GLOBAL VARIABLES AND FUNCTIONS
713		879
		880	These are not normally required to use AnyEvent, but can be useful to
		881	write AnyEvent extension modules.
		882
714	=over 4	883	=over 4
715		884
716	=item $AnyEvent::MODEL	885	=item $AnyEvent::MODEL
717		886
718	Contains C<undef> until the first watcher is being created. Then it	887	Contains C<undef> until the first watcher is being created, before the
		888	backend has been autodetected.
		889
719	contains the event model that is being used, which is the name of the	890	Afterwards it contains the event model that is being used, which is the
720	Perl class implementing the model. This class is usually one of the	891	name of the Perl class implementing the model. This class is usually one
721	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	892	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
722	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	893	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
723		894	will be C<urxvt::anyevent>).
724	The known classes so far are:
725
726	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
727	AnyEvent::Impl::Event based on Event, second best choice.
728	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
729	AnyEvent::Impl::Glib based on Glib, third-best choice.
730	AnyEvent::Impl::Tk based on Tk, very bad choice.
731	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
732	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
733	AnyEvent::Impl::POE based on POE, not generic enough for full support.
734
735	There is no support for WxWidgets, as WxWidgets has no support for
736	watching file handles. However, you can use WxWidgets through the
737	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
738	second, which was considered to be too horrible to even consider for
739	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
740	it's adaptor.
741
742	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
743	autodetecting them.
744		895
745	=item AnyEvent::detect	896	=item AnyEvent::detect
746		897
747	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	898	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
748	if necessary. You should only call this function right before you would	899	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	900	have created an AnyEvent watcher anyway, that is, as late as possible at
750	runtime.	901	runtime, and not e.g. while initialising of your module.
		902
		903	If you need to do some initialisation before AnyEvent watchers are
		904	created, use C<post_detect>.
751		905
752	=item $guard = AnyEvent::post_detect { BLOCK }	906	=item $guard = AnyEvent::post_detect { BLOCK }
753		907
754	Arranges for the code block to be executed as soon as the event model is	908	Arranges for the code block to be executed as soon as the event model is
755	autodetected (or immediately if this has already happened).	909	autodetected (or immediately if this has already happened).
756		910
		911	The block will be executed I<after> the actual backend has been detected
		912	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		913	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		914	other initialisations - see the sources of L<AnyEvent::Strict> or
		915	L<AnyEvent::AIO> to see how this is used.
		916
		917	The most common usage is to create some global watchers, without forcing
		918	event module detection too early, for example, L<AnyEvent::AIO> creates
		919	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		920	avoid autodetecting the event module at load time.
		921
757	If called in scalar or list context, then it creates and returns an object	922	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	923	that automatically removes the callback again when it is destroyed (or
		924	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
759	L<Coro::BDB> for a case where this is useful.	925	a case where this is useful.
		926
		927	Example: Create a watcher for the IO::AIO module and store it in
		928	C<$WATCHER>. Only do so after the event loop is initialised, though.
		929
		930	our WATCHER;
		931
		932	my $guard = AnyEvent::post_detect {
		933	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		934	};
		935
		936	# the ||= is important in case post_detect immediately runs the block,
		937	# as to not clobber the newly-created watcher. assigning both watcher and
		938	# post_detect guard to the same variable has the advantage of users being
		939	# able to just C<undef $WATCHER> if the watcher causes them grief.
		940
		941	$WATCHER ||= $guard;
760		942
761	=item @AnyEvent::post_detect	943	=item @AnyEvent::post_detect
762		944
763	If there are any code references in this array (you can C<push> to it	945	If there are any code references in this array (you can C<push> to it
764	before or after loading AnyEvent), then they will called directly after	946	before or after loading AnyEvent), then they will called directly after
765	the event loop has been chosen.	947	the event loop has been chosen.
766		948
767	You should check C<$AnyEvent::MODEL> before adding to this array, though:	949	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,	950	if it is defined then the event loop has already been detected, and the
769	and the array will be ignored.	951	array will be ignored.
770		952
771	Best use C<AnyEvent::post_detect { BLOCK }> instead.	953	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		954	it,as it takes care of these details.
		955
		956	This variable is mainly useful for modules that can do something useful
		957	when AnyEvent is used and thus want to know when it is initialised, but do
		958	not need to even load it by default. This array provides the means to hook
		959	into AnyEvent passively, without loading it.
772		960
773	=back	961	=back
774		962
775	=head1 WHAT TO DO IN A MODULE	963	=head1 WHAT TO DO IN A MODULE
776		964
…		…
831		1019
832		1020
833	=head1 OTHER MODULES	1021	=head1 OTHER MODULES
834		1022
835	The following is a non-exhaustive list of additional modules that use	1023	The following is a non-exhaustive list of additional modules that use
836	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1024	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	1025	modules and other event loops in the same program. Some of the modules
838	available via CPAN.	1026	come with AnyEvent, most are available via CPAN.
839		1027
840	=over 4	1028	=over 4
841		1029
842	=item L<AnyEvent::Util>	1030	=item L<AnyEvent::Util>
843		1031
…		…
852		1040
853	=item L<AnyEvent::Handle>	1041	=item L<AnyEvent::Handle>
854		1042
855	Provide read and write buffers, manages watchers for reads and writes,	1043	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	1044	supports raw and formatted I/O, I/O queued and fully transparent and
857	non-blocking SSL/TLS.	1045	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
858		1046
859	=item L<AnyEvent::DNS>	1047	=item L<AnyEvent::DNS>
860		1048
861	Provides rich asynchronous DNS resolver capabilities.	1049	Provides rich asynchronous DNS resolver capabilities.
862		1050
…		…
890		1078
891	=item L<AnyEvent::GPSD>	1079	=item L<AnyEvent::GPSD>
892		1080
893	A non-blocking interface to gpsd, a daemon delivering GPS information.	1081	A non-blocking interface to gpsd, a daemon delivering GPS information.
894		1082
		1083	=item L<AnyEvent::IRC>
		1084
		1085	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1086
		1087	=item L<AnyEvent::XMPP>
		1088
		1089	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1090	Net::XMPP2>.
		1091
895	=item L<AnyEvent::IGS>	1092	=item L<AnyEvent::IGS>
896		1093
897	A non-blocking interface to the Internet Go Server protocol (used by	1094	A non-blocking interface to the Internet Go Server protocol (used by
898	L<App::IGS>).	1095	L<App::IGS>).
899		1096
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>	1097	=item L<Net::FCP>
909		1098
910	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1099	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
911	of AnyEvent.	1100	of AnyEvent.
912		1101
…		…
916		1105
917	=item L<Coro>	1106	=item L<Coro>
918		1107
919	Has special support for AnyEvent via L<Coro::AnyEvent>.	1108	Has special support for AnyEvent via L<Coro::AnyEvent>.
920		1109
921	=item L<IO::Lambda>
922
923	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
924
925	=back	1110	=back
926		1111
927	=cut	1112	=cut
928		1113
929	package AnyEvent;	1114	package AnyEvent;
930		1115
931	no warnings;	1116	# basically a tuned-down version of common::sense
		1117	sub common_sense {
		1118	# from common:.sense 1.0
		1119	${^WARNING_BITS} = "\xfc\x3f\xf3\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x03";
932	use strict qw(vars subs);	1120	# use strict vars subs
		1121	$^H |= 0x00000600;
		1122	}
933		1123
		1124	BEGIN { AnyEvent::common_sense }
		1125
934	use Carp;	1126	use Carp ();
935		1127
936	our $VERSION = 4.41;	1128	our $VERSION = '5.21';
937	our $MODEL;	1129	our $MODEL;
938		1130
939	our $AUTOLOAD;	1131	our $AUTOLOAD;
940	our @ISA;	1132	our @ISA;
941		1133
942	our @REGISTRY;	1134	our @REGISTRY;
943		1135
944	our $WIN32;	1136	our $VERBOSE;
945		1137
946	BEGIN {	1138	BEGIN {
947	my $win32 = ! ! ($^O =~ /mswin32/i);	1139	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
948	eval "sub WIN32(){ $win32 }";	1140	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
949	}
950		1141
		1142	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1143	if ${^TAINT};
		1144
951	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1145	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1146
		1147	}
		1148
		1149	our $MAX_SIGNAL_LATENCY = 10;
952		1150
953	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1151	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
954		1152
955	{	1153	{
956	my $idx;	1154	my $idx;
…		…
958	for reverse split /\s*,\s*/,	1156	for reverse split /\s*,\s*/,
959	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1157	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
960	}	1158	}
961		1159
962	my @models = (	1160	my @models = (
963	[EV:: => AnyEvent::Impl::EV::],	1161	[EV:: => AnyEvent::Impl::EV:: , 1],
964	[Event:: => AnyEvent::Impl::Event::],
965	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1162	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
966	# everything below here will not be autoprobed	1163	# everything below here will not (normally) be autoprobed
967	# as the pureperl backend should work everywhere	1164	# as the pureperl backend should work everywhere
968	# and is usually faster	1165	# and is usually faster
		1166	[Event:: => AnyEvent::Impl::Event::, 1],
		1167	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1168	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1169	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
969	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1170	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
970	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
971	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
972	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1171	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
973	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1172	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
974	[Wx:: => AnyEvent::Impl::POE::],	1173	[Wx:: => AnyEvent::Impl::POE::],
975	[Prima:: => AnyEvent::Impl::POE::],	1174	[Prima:: => AnyEvent::Impl::POE::],
		1175	# IO::Async is just too broken - we would need workarounds for its
		1176	# byzantine signal and broken child handling, among others.
		1177	# IO::Async is rather hard to detect, as it doesn't have any
		1178	# obvious default class.
		1179	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1180	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1181	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1182	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
976	);	1183	);
977		1184
978	our %method = map +($_ => 1),	1185	our %method = map +($_ => 1),
979	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1186	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
980		1187
…		…
984	my ($cb) = @_;	1191	my ($cb) = @_;
985		1192
986	if ($MODEL) {	1193	if ($MODEL) {
987	$cb->();	1194	$cb->();
988		1195
989	1	1196	undef
990	} else {	1197	} else {
991	push @post_detect, $cb;	1198	push @post_detect, $cb;
992		1199
993	defined wantarray	1200	defined wantarray
994	? bless \$cb, "AnyEvent::Util::postdetect"	1201	? bless \$cb, "AnyEvent::Util::postdetect"
…		…
1000	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1207	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1001	}	1208	}
1002		1209
1003	sub detect() {	1210	sub detect() {
1004	unless ($MODEL) {	1211	unless ($MODEL) {
1005	no strict 'refs';
1006	local $SIG{__DIE__};	1212	local $SIG{__DIE__};
1007		1213
1008	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1214	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1009	my $model = "AnyEvent::Impl::$1";	1215	my $model = "AnyEvent::Impl::$1";
1010	if (eval "require $model") {	1216	if (eval "require $model") {
1011	$MODEL = $model;	1217	$MODEL = $model;
1012	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1218	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1013	} else {	1219	} else {
1014	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1220	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1015	}	1221	}
1016	}	1222	}
1017		1223
1018	# check for already loaded models	1224	# check for already loaded models
1019	unless ($MODEL) {	1225	unless ($MODEL) {
1020	for (@REGISTRY, @models) {	1226	for (@REGISTRY, @models) {
1021	my ($package, $model) = @$_;	1227	my ($package, $model) = @$_;
1022	if (${"$package\::VERSION"} > 0) {	1228	if (${"$package\::VERSION"} > 0) {
1023	if (eval "require $model") {	1229	if (eval "require $model") {
1024	$MODEL = $model;	1230	$MODEL = $model;
1025	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1231	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1026	last;	1232	last;
1027	}	1233	}
1028	}	1234	}
1029	}	1235	}
1030		1236
1031	unless ($MODEL) {	1237	unless ($MODEL) {
1032	# try to load a model	1238	# try to autoload a model
1033
1034	for (@REGISTRY, @models) {	1239	for (@REGISTRY, @models) {
1035	my ($package, $model) = @$_;	1240	my ($package, $model, $autoload) = @$_;
		1241	if (
		1242	$autoload
1036	if (eval "require $package"	1243	and eval "require $package"
1037	and ${"$package\::VERSION"} > 0	1244	and ${"$package\::VERSION"} > 0
1038	and eval "require $model") {	1245	and eval "require $model"
		1246	) {
1039	$MODEL = $model;	1247	$MODEL = $model;
1040	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1248	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1041	last;	1249	last;
1042	}	1250	}
1043	}	1251	}
1044		1252
1045	$MODEL	1253	$MODEL
…		…
1061		1269
1062	sub AUTOLOAD {	1270	sub AUTOLOAD {
1063	(my $func = $AUTOLOAD) =~ s/.*://;	1271	(my $func = $AUTOLOAD) =~ s/.*://;
1064		1272
1065	$method{$func}	1273	$method{$func}
1066	or croak "$func: not a valid method for AnyEvent objects";	1274	or Carp::croak "$func: not a valid method for AnyEvent objects";
1067		1275
1068	detect unless $MODEL;	1276	detect unless $MODEL;
1069		1277
1070	my $class = shift;	1278	my $class = shift;
1071	$class->$func (@_);	1279	$class->$func (@_);
1072	}	1280	}
1073		1281
1074	# utility function to dup a filehandle. this is used by many backends	1282	# utility function to dup a filehandle. this is used by many backends
1075	# to support binding more than one watcher per filehandle (they usually	1283	# to support binding more than one watcher per filehandle (they usually
1076	# allow only one watcher per fd, so we dup it to get a different one).	1284	# allow only one watcher per fd, so we dup it to get a different one).
1077	sub _dupfh($$$$) {	1285	sub _dupfh($$;$$) {
1078	my ($poll, $fh, $r, $w) = @_;	1286	my ($poll, $fh, $r, $w) = @_;
1079		1287
1080	# cygwin requires the fh mode to be matching, unix doesn't	1288	# cygwin requires the fh mode to be matching, unix doesn't
1081	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1289	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1082	: $poll eq "w" ? ($w, ">")
1083	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1084		1290
1085	open my $fh2, "$mode&" . fileno $fh	1291	open my $fh2, $mode, $fh
1086	or die "cannot dup() filehandle: $!,";	1292	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1087		1293
1088	# we assume CLOEXEC is already set by perl in all important cases	1294	# we assume CLOEXEC is already set by perl in all important cases
1089		1295
1090	($fh2, $rw)	1296	($fh2, $rw)
1091	}	1297	}
1092		1298
		1299	=head1 SIMPLIFIED AE API
		1300
		1301	Starting with version 5.0, AnyEvent officially supports a second, much
		1302	simpler, API that is designed to reduce the calling, typing and memory
		1303	overhead.
		1304
		1305	See the L<AE> manpage for details.
		1306
		1307	=cut
		1308
		1309	package AE;
		1310
		1311	our $VERSION = $AnyEvent::VERSION;
		1312
		1313	sub io($$$) {
		1314	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1315	}
		1316
		1317	sub timer($$$) {
		1318	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1319	}
		1320
		1321	sub signal($$) {
		1322	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1323	}
		1324
		1325	sub child($$) {
		1326	AnyEvent->child (pid => $_[0], cb => $_[1])
		1327	}
		1328
		1329	sub idle($) {
		1330	AnyEvent->idle (cb => $_[0])
		1331	}
		1332
		1333	sub cv(;&) {
		1334	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1335	}
		1336
		1337	sub now() {
		1338	AnyEvent->now
		1339	}
		1340
		1341	sub now_update() {
		1342	AnyEvent->now_update
		1343	}
		1344
		1345	sub time() {
		1346	AnyEvent->time
		1347	}
		1348
1093	package AnyEvent::Base;	1349	package AnyEvent::Base;
1094		1350
1095	# default implementations for many methods	1351	# default implementations for many methods
1096		1352
1097	BEGIN {	1353	sub _time() {
		1354	# probe for availability of Time::HiRes
1098	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1355	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1356	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1099	*_time = \&Time::HiRes::time;	1357	*_time = \&Time::HiRes::time;
1100	# if (eval "use POSIX (); (POSIX::times())...	1358	# if (eval "use POSIX (); (POSIX::times())...
1101	} else {	1359	} else {
		1360	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1102	*_time = sub { time }; # epic fail	1361	*_time = sub { time }; # epic fail
1103	}	1362	}
		1363
		1364	&_time
1104	}	1365	}
1105		1366
1106	sub time { _time }	1367	sub time { _time }
1107	sub now { _time }	1368	sub now { _time }
1108	sub now_update { }	1369	sub now_update { }
…		…
1113	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1374	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1114	}	1375	}
1115		1376
1116	# default implementation for ->signal	1377	# default implementation for ->signal
1117		1378
		1379	our $HAVE_ASYNC_INTERRUPT;
		1380
		1381	sub _have_async_interrupt() {
		1382	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1383	&& eval "use Async::Interrupt 1.02 (); 1")
		1384	unless defined $HAVE_ASYNC_INTERRUPT;
		1385
		1386	$HAVE_ASYNC_INTERRUPT
		1387	}
		1388
1118	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1389	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1390	our (%SIG_ASY, %SIG_ASY_W);
		1391	our ($SIG_COUNT, $SIG_TW);
1119		1392
1120	sub _signal_exec {	1393	sub _signal_exec {
		1394	$HAVE_ASYNC_INTERRUPT
		1395	? $SIGPIPE_R->drain
1121	sysread $SIGPIPE_R, my $dummy, 4;	1396	: sysread $SIGPIPE_R, (my $dummy), 9;
1122		1397
1123	while (%SIG_EV) {	1398	while (%SIG_EV) {
1124	for (keys %SIG_EV) {	1399	for (keys %SIG_EV) {
1125	delete $SIG_EV{$_};	1400	delete $SIG_EV{$_};
1126	$_->() for values %{ $SIG_CB{$_} || {} };	1401	$_->() for values %{ $SIG_CB{$_} || {} };
1127	}	1402	}
1128	}	1403	}
1129	}	1404	}
1130		1405
		1406	# install a dummy wakeup watcher to reduce signal catching latency
		1407	sub _sig_add() {
		1408	unless ($SIG_COUNT++) {
		1409	# try to align timer on a full-second boundary, if possible
		1410	my $NOW = AE::now;
		1411
		1412	$SIG_TW = AE::timer
		1413	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1414	$MAX_SIGNAL_LATENCY,
		1415	sub { } # just for the PERL_ASYNC_CHECK
		1416	;
		1417	}
		1418	}
		1419
		1420	sub _sig_del {
		1421	undef $SIG_TW
		1422	unless --$SIG_COUNT;
		1423	}
		1424
		1425	our $_sig_name_init; $_sig_name_init = sub {
		1426	eval q{ # poor man's autoloading
		1427	undef $_sig_name_init;
		1428
		1429	if (_have_async_interrupt) {
		1430	*sig2num = \&Async::Interrupt::sig2num;
		1431	*sig2name = \&Async::Interrupt::sig2name;
		1432	} else {
		1433	require Config;
		1434
		1435	my %signame2num;
		1436	@signame2num{ split ' ', $Config::Config{sig_name} }
		1437	= split ' ', $Config::Config{sig_num};
		1438
		1439	my @signum2name;
		1440	@signum2name[values %signame2num] = keys %signame2num;
		1441
		1442	*sig2num = sub($) {
		1443	$_[0] > 0 ? shift : $signame2num{+shift}
		1444	};
		1445	*sig2name = sub ($) {
		1446	$_[0] > 0 ? $signum2name[+shift] : shift
		1447	};
		1448	}
		1449	};
		1450	die if $@;
		1451	};
		1452
		1453	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1454	sub sig2name($) { &$_sig_name_init; &sig2name }
		1455
1131	sub signal {	1456	sub signal {
1132	my (undef, %arg) = @_;	1457	eval q{ # poor man's autoloading {}
		1458	# probe for availability of Async::Interrupt
		1459	if (_have_async_interrupt) {
		1460	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1133		1461
1134	unless ($SIGPIPE_R) {	1462	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1135	require Fcntl;	1463	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1136		1464
1137	if (AnyEvent::WIN32) {
1138	require AnyEvent::Util;
1139
1140	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1141	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1142	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1143	} else {	1465	} else {
		1466	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1467
		1468	require Fcntl;
		1469
		1470	if (AnyEvent::WIN32) {
		1471	require AnyEvent::Util;
		1472
		1473	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1474	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1475	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1476	} else {
1144	pipe $SIGPIPE_R, $SIGPIPE_W;	1477	pipe $SIGPIPE_R, $SIGPIPE_W;
1145	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1478	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1146	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1479	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1147		1480
1148	# not strictly required, as $^F is normally 2, but let's make sure...	1481	# not strictly required, as $^F is normally 2, but let's make sure...
1149	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1482	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1150	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1483	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1484	}
		1485
		1486	$SIGPIPE_R
		1487	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1488
		1489	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1151	}	1490	}
1152		1491
1153	$SIGPIPE_R	1492	*signal = sub {
1154	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1493	my (undef, %arg) = @_;
1155		1494
1156	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1157	}
1158
1159	my $signal = uc $arg{signal}	1495	my $signal = uc $arg{signal}
1160	or Carp::croak "required option 'signal' is missing";	1496	or Carp::croak "required option 'signal' is missing";
1161		1497
		1498	if ($HAVE_ASYNC_INTERRUPT) {
		1499	# async::interrupt
		1500
		1501	$signal = sig2num $signal;
1162	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1502	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1503
		1504	$SIG_ASY{$signal} ||= new Async::Interrupt
		1505	cb => sub { undef $SIG_EV{$signal} },
		1506	signal => $signal,
		1507	pipe => [$SIGPIPE_R->filenos],
		1508	pipe_autodrain => 0,
		1509	;
		1510
		1511	} else {
		1512	# pure perl
		1513
		1514	# AE::Util has been loaded in signal
		1515	$signal = sig2name $signal;
		1516	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1517
1163	$SIG{$signal} ||= sub {	1518	$SIG{$signal} ||= sub {
1164	local $!;	1519	local $!;
1165	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1520	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1166	undef $SIG_EV{$signal};	1521	undef $SIG_EV{$signal};
		1522	};
		1523
		1524	# can't do signal processing without introducing races in pure perl,
		1525	# so limit the signal latency.
		1526	_sig_add;
		1527	}
		1528
		1529	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1530	};
		1531
		1532	*AnyEvent::Base::signal::DESTROY = sub {
		1533	my ($signal, $cb) = @{$_[0]};
		1534
		1535	_sig_del;
		1536
		1537	delete $SIG_CB{$signal}{$cb};
		1538
		1539	$HAVE_ASYNC_INTERRUPT
		1540	? delete $SIG_ASY{$signal}
		1541	: # delete doesn't work with older perls - they then
		1542	# print weird messages, or just unconditionally exit
		1543	# instead of getting the default action.
		1544	undef $SIG{$signal}
		1545	unless keys %{ $SIG_CB{$signal} };
		1546	};
1167	};	1547	};
1168		1548	die if $@;
1169	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1549	&signal
1170	}
1171
1172	sub AnyEvent::Base::signal::DESTROY {
1173	my ($signal, $cb) = @{$_[0]};
1174
1175	delete $SIG_CB{$signal}{$cb};
1176
1177	# delete doesn't work with older perls - they then
1178	# print weird messages, or just unconditionally exit
1179	# instead of getting the default action.
1180	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1181	}	1550	}
1182		1551
1183	# default implementation for ->child	1552	# default implementation for ->child
1184		1553
1185	our %PID_CB;	1554	our %PID_CB;
1186	our $CHLD_W;	1555	our $CHLD_W;
1187	our $CHLD_DELAY_W;	1556	our $CHLD_DELAY_W;
1188	our $WNOHANG;	1557	our $WNOHANG;
1189		1558
		1559	sub _emit_childstatus($$) {
		1560	my (undef, $rpid, $rstatus) = @_;
		1561
		1562	$_->($rpid, $rstatus)
		1563	for values %{ $PID_CB{$rpid} || {} },
		1564	values %{ $PID_CB{0} || {} };
		1565	}
		1566
1190	sub _sigchld {	1567	sub _sigchld {
		1568	my $pid;
		1569
		1570	AnyEvent->_emit_childstatus ($pid, $?)
1191	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1571	while ($pid = waitpid -1, $WNOHANG) > 0;
1192	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),
1193	(values %{ $PID_CB{0} || {} });
1194	}
1195	}	1572	}
1196		1573
1197	sub child {	1574	sub child {
1198	my (undef, %arg) = @_;	1575	my (undef, %arg) = @_;
1199		1576
1200	defined (my $pid = $arg{pid} + 0)	1577	defined (my $pid = $arg{pid} + 0)
1201	or Carp::croak "required option 'pid' is missing";	1578	or Carp::croak "required option 'pid' is missing";
1202		1579
1203	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1580	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1204		1581
		1582	# WNOHANG is almost cetrainly 1 everywhere
		1583	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1584	? 1
1205	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1585	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1206		1586
1207	unless ($CHLD_W) {	1587	unless ($CHLD_W) {
1208	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1588	$CHLD_W = AE::signal CHLD => \&_sigchld;
1209	# child could be a zombie already, so make at least one round	1589	# child could be a zombie already, so make at least one round
1210	&_sigchld;	1590	&_sigchld;
1211	}	1591	}
1212		1592
1213	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1593	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
…		…
1239	# never use more then 50% of the time for the idle watcher,	1619	# never use more then 50% of the time for the idle watcher,
1240	# within some limits	1620	# within some limits
1241	$w = 0.0001 if $w < 0.0001;	1621	$w = 0.0001 if $w < 0.0001;
1242	$w = 5 if $w > 5;	1622	$w = 5 if $w > 5;
1243		1623
1244	$w = AnyEvent->timer (after => $w, cb => $rcb);	1624	$w = AE::timer $w, 0, $rcb;
1245	} else {	1625	} else {
1246	# clean up...	1626	# clean up...
1247	undef $w;	1627	undef $w;
1248	undef $rcb;	1628	undef $rcb;
1249	}	1629	}
1250	};	1630	};
1251		1631
1252	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1632	$w = AE::timer 0.05, 0, $rcb;
1253		1633
1254	bless \\$cb, "AnyEvent::Base::idle"	1634	bless \\$cb, "AnyEvent::Base::idle"
1255	}	1635	}
1256		1636
1257	sub AnyEvent::Base::idle::DESTROY {	1637	sub AnyEvent::Base::idle::DESTROY {
…		…
1262		1642
1263	our @ISA = AnyEvent::CondVar::Base::;	1643	our @ISA = AnyEvent::CondVar::Base::;
1264		1644
1265	package AnyEvent::CondVar::Base;	1645	package AnyEvent::CondVar::Base;
1266		1646
1267	use overload	1647	#use overload
1268	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1648	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1269	fallback => 1;	1649	# fallback => 1;
		1650
		1651	# save 300+ kilobytes by dirtily hardcoding overloading
		1652	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1653	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1654	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1655	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1656
		1657	our $WAITING;
1270		1658
1271	sub _send {	1659	sub _send {
1272	# nop	1660	# nop
1273	}	1661	}
1274		1662
…		…
1287	sub ready {	1675	sub ready {
1288	$_[0]{_ae_sent}	1676	$_[0]{_ae_sent}
1289	}	1677	}
1290		1678
1291	sub _wait {	1679	sub _wait {
		1680	$WAITING
		1681	and !$_[0]{_ae_sent}
		1682	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1683
		1684	local $WAITING = 1;
1292	AnyEvent->one_event while !$_[0]{_ae_sent};	1685	AnyEvent->one_event while !$_[0]{_ae_sent};
1293	}	1686	}
1294		1687
1295	sub recv {	1688	sub recv {
1296	$_[0]->_wait;	1689	$_[0]->_wait;
…		…
1298	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1691	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1299	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1692	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1300	}	1693	}
1301		1694
1302	sub cb {	1695	sub cb {
1303	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1696	my $cv = shift;
		1697
		1698	@_
		1699	and $cv->{_ae_cb} = shift
		1700	and $cv->{_ae_sent}
		1701	and (delete $cv->{_ae_cb})->($cv);
		1702
1304	$_[0]{_ae_cb}	1703	$cv->{_ae_cb}
1305	}	1704	}
1306		1705
1307	sub begin {	1706	sub begin {
1308	++$_[0]{_ae_counter};	1707	++$_[0]{_ae_counter};
1309	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1708	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1337	so on.	1736	so on.
1338		1737
1339	=head1 ENVIRONMENT VARIABLES	1738	=head1 ENVIRONMENT VARIABLES
1340		1739
1341	The following environment variables are used by this module or its	1740	The following environment variables are used by this module or its
1342	submodules:	1741	submodules.
		1742
		1743	Note that AnyEvent will remove I<all> environment variables starting with
		1744	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1745	enabled.
1343		1746
1344	=over 4	1747	=over 4
1345		1748
1346	=item C<PERL_ANYEVENT_VERBOSE>	1749	=item C<PERL_ANYEVENT_VERBOSE>
1347		1750
…		…
1354	C<PERL_ANYEVENT_MODEL>.	1757	C<PERL_ANYEVENT_MODEL>.
1355		1758
1356	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1759	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1357	model it chooses.	1760	model it chooses.
1358		1761
		1762	When set to C<8> or higher, then AnyEvent will report extra information on
		1763	which optional modules it loads and how it implements certain features.
		1764
1359	=item C<PERL_ANYEVENT_STRICT>	1765	=item C<PERL_ANYEVENT_STRICT>
1360		1766
1361	AnyEvent does not do much argument checking by default, as thorough	1767	AnyEvent does not do much argument checking by default, as thorough
1362	argument checking is very costly. Setting this variable to a true value	1768	argument checking is very costly. Setting this variable to a true value
1363	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1769	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1364	check the arguments passed to most method calls. If it finds any problems	1770	check the arguments passed to most method calls. If it finds any problems,
1365	it will croak.	1771	it will croak.
1366		1772
1367	In other words, enables "strict" mode.	1773	In other words, enables "strict" mode.
1368		1774
1369	Unlike C<use strict>, it is definitely recommended ot keep it off in	1775	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1370	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1776	>>, it is definitely recommended to keep it off in production. Keeping
1371	developing programs can be very useful, however.	1777	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1778	can be very useful, however.
1372		1779
1373	=item C<PERL_ANYEVENT_MODEL>	1780	=item C<PERL_ANYEVENT_MODEL>
1374		1781
1375	This can be used to specify the event model to be used by AnyEvent, before	1782	This can be used to specify the event model to be used by AnyEvent, before
1376	auto detection and -probing kicks in. It must be a string consisting	1783	auto detection and -probing kicks in. It must be a string consisting
…		…
1419		1826
1420	=item C<PERL_ANYEVENT_MAX_FORKS>	1827	=item C<PERL_ANYEVENT_MAX_FORKS>
1421		1828
1422	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1829	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1423	will create in parallel.	1830	will create in parallel.
		1831
		1832	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1833
		1834	The default value for the C<max_outstanding> parameter for the default DNS
		1835	resolver - this is the maximum number of parallel DNS requests that are
		1836	sent to the DNS server.
		1837
		1838	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1839
		1840	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1841	configuration) in the default resolver. When set to the empty string, no
		1842	default config will be used.
		1843
		1844	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1845
		1846	When neither C<ca_file> nor C<ca_path> was specified during
		1847	L<AnyEvent::TLS> context creation, and either of these environment
		1848	variables exist, they will be used to specify CA certificate locations
		1849	instead of a system-dependent default.
		1850
		1851	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1852
		1853	When these are set to C<1>, then the respective modules are not
		1854	loaded. Mostly good for testing AnyEvent itself.
1424		1855
1425	=back	1856	=back
1426		1857
1427	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1858	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1428		1859
…		…
1486	warn "read: $input\n"; # output what has been read	1917	warn "read: $input\n"; # output what has been read
1487	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1918	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1488	},	1919	},
1489	);	1920	);
1490		1921
1491	my $time_watcher; # can only be used once
1492
1493	sub new_timer {
1494	$timer = AnyEvent->timer (after => 1, cb => sub {	1922	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1495	warn "timeout\n"; # print 'timeout' about every second	1923	warn "timeout\n"; # print 'timeout' at most every second
1496	&new_timer; # and restart the time
1497	});	1924	});
1498	}
1499
1500	new_timer; # create first timer
1501		1925
1502	$cv->recv; # wait until user enters /^q/i	1926	$cv->recv; # wait until user enters /^q/i
1503		1927
1504	=head1 REAL-WORLD EXAMPLE	1928	=head1 REAL-WORLD EXAMPLE
1505		1929
…		…
1636	through AnyEvent. The benchmark creates a lot of timers (with a zero	2060	through AnyEvent. The benchmark creates a lot of timers (with a zero
1637	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2061	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1638	which it is), lets them fire exactly once and destroys them again.	2062	which it is), lets them fire exactly once and destroys them again.
1639		2063
1640	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2064	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1641	distribution.	2065	distribution. It uses the L<AE> interface, which makes a real difference
		2066	for the EV and Perl backends only.
1642		2067
1643	=head3 Explanation of the columns	2068	=head3 Explanation of the columns
1644		2069
1645	I<watcher> is the number of event watchers created/destroyed. Since	2070	I<watcher> is the number of event watchers created/destroyed. Since
1646	different event models feature vastly different performances, each event	2071	different event models feature vastly different performances, each event
…		…
1667	watcher.	2092	watcher.
1668		2093
1669	=head3 Results	2094	=head3 Results
1670		2095
1671	name watchers bytes create invoke destroy comment	2096	name watchers bytes create invoke destroy comment
1672	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2097	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1673	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2098	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1674	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2099	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1675	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2100	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1676	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2101	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1677	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2102	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2103	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2104	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1678	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2105	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1679	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2106	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1680	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2107	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1681	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2108	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1682		2109
1683	=head3 Discussion	2110	=head3 Discussion
1684		2111
1685	The benchmark does I<not> measure scalability of the event loop very	2112	The benchmark does I<not> measure scalability of the event loop very
1686	well. For example, a select-based event loop (such as the pure perl one)	2113	well. For example, a select-based event loop (such as the pure perl one)
…		…
1698	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2125	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1699	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2126	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1700	cycles with POE.	2127	cycles with POE.
1701		2128
1702	C<EV> is the sole leader regarding speed and memory use, which are both	2129	C<EV> is the sole leader regarding speed and memory use, which are both
1703	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2130	maximal/minimal, respectively. When using the L<AE> API there is zero
		2131	overhead (when going through the AnyEvent API create is about 5-6 times
		2132	slower, with other times being equal, so still uses far less memory than
1704	far less memory than any other event loop and is still faster than Event	2133	any other event loop and is still faster than Event natively).
1705	natively.
1706		2134
1707	The pure perl implementation is hit in a few sweet spots (both the	2135	The pure perl implementation is hit in a few sweet spots (both the
1708	constant timeout and the use of a single fd hit optimisations in the perl	2136	constant timeout and the use of a single fd hit optimisations in the perl
1709	interpreter and the backend itself). Nevertheless this shows that it	2137	interpreter and the backend itself). Nevertheless this shows that it
1710	adds very little overhead in itself. Like any select-based backend its	2138	adds very little overhead in itself. Like any select-based backend its
1711	performance becomes really bad with lots of file descriptors (and few of	2139	performance becomes really bad with lots of file descriptors (and few of
1712	them active), of course, but this was not subject of this benchmark.	2140	them active), of course, but this was not subject of this benchmark.
1713		2141
1714	The C<Event> module has a relatively high setup and callback invocation	2142	The C<Event> module has a relatively high setup and callback invocation
1715	cost, but overall scores in on the third place.	2143	cost, but overall scores in on the third place.
		2144
		2145	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2146	when using its pure perl backend.
1716		2147
1717	C<Glib>'s memory usage is quite a bit higher, but it features a	2148	C<Glib>'s memory usage is quite a bit higher, but it features a
1718	faster callback invocation and overall ends up in the same class as	2149	faster callback invocation and overall ends up in the same class as
1719	C<Event>. However, Glib scales extremely badly, doubling the number of	2150	C<Event>. However, Glib scales extremely badly, doubling the number of
1720	watchers increases the processing time by more than a factor of four,	2151	watchers increases the processing time by more than a factor of four,
…		…
1781	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2212	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1782	(1%) are active. This mirrors the activity of large servers with many	2213	(1%) are active. This mirrors the activity of large servers with many
1783	connections, most of which are idle at any one point in time.	2214	connections, most of which are idle at any one point in time.
1784		2215
1785	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2216	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1786	distribution.	2217	distribution. It uses the L<AE> interface, which makes a real difference
		2218	for the EV and Perl backends only.
1787		2219
1788	=head3 Explanation of the columns	2220	=head3 Explanation of the columns
1789		2221
1790	I<sockets> is the number of sockets, and twice the number of "servers" (as	2222	I<sockets> is the number of sockets, and twice the number of "servers" (as
1791	each server has a read and write socket end).	2223	each server has a read and write socket end).
…		…
1798	it to another server. This includes deleting the old timeout and creating	2230	it to another server. This includes deleting the old timeout and creating
1799	a new one that moves the timeout into the future.	2231	a new one that moves the timeout into the future.
1800		2232
1801	=head3 Results	2233	=head3 Results
1802		2234
1803	name sockets create request	2235	name sockets create request
1804	EV 20000 69.01 11.16	2236	EV 20000 62.66 7.99
1805	Perl 20000 73.32 35.87	2237	Perl 20000 68.32 32.64
1806	Event 20000 212.62 257.32	2238	IOAsync 20000 174.06 101.15 epoll
1807	Glib 20000 651.16 1896.30	2239	IOAsync 20000 174.67 610.84 poll
		2240	Event 20000 202.69 242.91
		2241	Glib 20000 557.01 1689.52
1808	POE 20000 349.67 12317.24 uses POE::Loop::Event	2242	POE 20000 341.54 12086.32 uses POE::Loop::Event
1809		2243
1810	=head3 Discussion	2244	=head3 Discussion
1811		2245
1812	This benchmark I<does> measure scalability and overall performance of the	2246	This benchmark I<does> measure scalability and overall performance of the
1813	particular event loop.	2247	particular event loop.
…		…
1815	EV is again fastest. Since it is using epoll on my system, the setup time	2249	EV is again fastest. Since it is using epoll on my system, the setup time
1816	is relatively high, though.	2250	is relatively high, though.
1817		2251
1818	Perl surprisingly comes second. It is much faster than the C-based event	2252	Perl surprisingly comes second. It is much faster than the C-based event
1819	loops Event and Glib.	2253	loops Event and Glib.
		2254
		2255	IO::Async performs very well when using its epoll backend, and still quite
		2256	good compared to Glib when using its pure perl backend.
1820		2257
1821	Event suffers from high setup time as well (look at its code and you will	2258	Event suffers from high setup time as well (look at its code and you will
1822	understand why). Callback invocation also has a high overhead compared to	2259	understand why). Callback invocation also has a high overhead compared to
1823	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2260	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1824	uses select or poll in basically all documented configurations.	2261	uses select or poll in basically all documented configurations.
…		…
1887	=item * C-based event loops perform very well with small number of	2324	=item * C-based event loops perform very well with small number of
1888	watchers, as the management overhead dominates.	2325	watchers, as the management overhead dominates.
1889		2326
1890	=back	2327	=back
1891		2328
		2329	=head2 THE IO::Lambda BENCHMARK
		2330
		2331	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2332	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2333	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2334	shouldn't come as a surprise to anybody). As such, the benchmark is
		2335	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2336	very optimal. But how would AnyEvent compare when used without the extra
		2337	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2338
		2339	The benchmark itself creates an echo-server, and then, for 500 times,
		2340	connects to the echo server, sends a line, waits for the reply, and then
		2341	creates the next connection. This is a rather bad benchmark, as it doesn't
		2342	test the efficiency of the framework or much non-blocking I/O, but it is a
		2343	benchmark nevertheless.
		2344
		2345	name runtime
		2346	Lambda/select 0.330 sec
		2347	+ optimized 0.122 sec
		2348	Lambda/AnyEvent 0.327 sec
		2349	+ optimized 0.138 sec
		2350	Raw sockets/select 0.077 sec
		2351	POE/select, components 0.662 sec
		2352	POE/select, raw sockets 0.226 sec
		2353	POE/select, optimized 0.404 sec
		2354
		2355	AnyEvent/select/nb 0.085 sec
		2356	AnyEvent/EV/nb 0.068 sec
		2357	+state machine 0.134 sec
		2358
		2359	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2360	benchmarks actually make blocking connects and use 100% blocking I/O,
		2361	defeating the purpose of an event-based solution. All of the newly
		2362	written AnyEvent benchmarks use 100% non-blocking connects (using
		2363	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2364	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2365	generally require a lot more bookkeeping and event handling than blocking
		2366	connects (which involve a single syscall only).
		2367
		2368	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2369	offers similar expressive power as POE and IO::Lambda, using conventional
		2370	Perl syntax. This means that both the echo server and the client are 100%
		2371	non-blocking, further placing it at a disadvantage.
		2372
		2373	As you can see, the AnyEvent + EV combination even beats the
		2374	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2375	backend easily beats IO::Lambda and POE.
		2376
		2377	And even the 100% non-blocking version written using the high-level (and
		2378	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2379	higher level ("unoptimised") abstractions by a large margin, even though
		2380	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
		2381
		2382	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2383	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2384	part of the IO::Lambda distribution and were used without any changes.
		2385
1892		2386
1893	=head1 SIGNALS	2387	=head1 SIGNALS
1894		2388
1895	AnyEvent currently installs handlers for these signals:	2389	AnyEvent currently installs handlers for these signals:
1896		2390
…		…
1899	=item SIGCHLD	2393	=item SIGCHLD
1900		2394
1901	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2395	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1902	emulation for event loops that do not support them natively. Also, some	2396	emulation for event loops that do not support them natively. Also, some
1903	event loops install a similar handler.	2397	event loops install a similar handler.
		2398
		2399	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2400	AnyEvent will reset it to default, to avoid losing child exit statuses.
1904		2401
1905	=item SIGPIPE	2402	=item SIGPIPE
1906		2403
1907	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2404	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1908	when AnyEvent gets loaded.	2405	when AnyEvent gets loaded.
…		…
1920		2417
1921	=back	2418	=back
1922		2419
1923	=cut	2420	=cut
1924		2421
		2422	undef $SIG{CHLD}
		2423	if $SIG{CHLD} eq 'IGNORE';
		2424
1925	$SIG{PIPE} = sub { }	2425	$SIG{PIPE} = sub { }
1926	unless defined $SIG{PIPE};	2426	unless defined $SIG{PIPE};
		2427
		2428	=head1 RECOMMENDED/OPTIONAL MODULES
		2429
		2430	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2431	it's built-in modules) are required to use it.
		2432
		2433	That does not mean that AnyEvent won't take advantage of some additional
		2434	modules if they are installed.
		2435
		2436	This section epxlains which additional modules will be used, and how they
		2437	affect AnyEvent's operetion.
		2438
		2439	=over 4
		2440
		2441	=item L<Async::Interrupt>
		2442
		2443	This slightly arcane module is used to implement fast signal handling: To
		2444	my knowledge, there is no way to do completely race-free and quick
		2445	signal handling in pure perl. To ensure that signals still get
		2446	delivered, AnyEvent will start an interval timer to wake up perl (and
		2447	catch the signals) with some delay (default is 10 seconds, look for
		2448	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2449
		2450	If this module is available, then it will be used to implement signal
		2451	catching, which means that signals will not be delayed, and the event loop
		2452	will not be interrupted regularly, which is more efficient (And good for
		2453	battery life on laptops).
		2454
		2455	This affects not just the pure-perl event loop, but also other event loops
		2456	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2457
		2458	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2459	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2460	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2461	does nothing for those backends.
		2462
		2463	=item L<EV>
		2464
		2465	This module isn't really "optional", as it is simply one of the backend
		2466	event loops that AnyEvent can use. However, it is simply the best event
		2467	loop available in terms of features, speed and stability: It supports
		2468	the AnyEvent API optimally, implements all the watcher types in XS, does
		2469	automatic timer adjustments even when no monotonic clock is available,
		2470	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2471	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2472	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2473
		2474	=item L<Guard>
		2475
		2476	The guard module, when used, will be used to implement
		2477	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2478	lot less memory), but otherwise doesn't affect guard operation much. It is
		2479	purely used for performance.
		2480
		2481	=item L<JSON> and L<JSON::XS>
		2482
		2483	One of these modules is required when you want to read or write JSON data
		2484	via L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2485	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2486
		2487	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2488	installed.
		2489
		2490	=item L<Net::SSLeay>
		2491
		2492	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2493	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2494	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2495
		2496	=item L<Time::HiRes>
		2497
		2498	This module is part of perl since release 5.008. It will be used when the
		2499	chosen event library does not come with a timing source on it's own. The
		2500	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2501	try to use a monotonic clock for timing stability.
		2502
		2503	=back
1927		2504
1928		2505
1929	=head1 FORK	2506	=head1 FORK
1930		2507
1931	Most event libraries are not fork-safe. The ones who are usually are	2508	Most event libraries are not fork-safe. The ones who are usually are
1932	because they rely on inefficient but fork-safe C<select> or C<poll>	2509	because they rely on inefficient but fork-safe C<select> or C<poll>
1933	calls. Only L<EV> is fully fork-aware.	2510	calls. Only L<EV> is fully fork-aware.
1934		2511
1935	If you have to fork, you must either do so I<before> creating your first	2512	If you have to fork, you must either do so I<before> creating your first
1936	watcher OR you must not use AnyEvent at all in the child.	2513	watcher OR you must not use AnyEvent at all in the child OR you must do
		2514	something completely out of the scope of AnyEvent.
1937		2515
1938		2516
1939	=head1 SECURITY CONSIDERATIONS	2517	=head1 SECURITY CONSIDERATIONS
1940		2518
1941	AnyEvent can be forced to load any event model via	2519	AnyEvent can be forced to load any event model via
…		…
1953	use AnyEvent;	2531	use AnyEvent;
1954		2532
1955	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2533	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1956	be used to probe what backend is used and gain other information (which is	2534	be used to probe what backend is used and gain other information (which is
1957	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2535	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1958	$ENV{PERL_ANYEGENT_STRICT}.	2536	$ENV{PERL_ANYEVENT_STRICT}.
		2537
		2538	Note that AnyEvent will remove I<all> environment variables starting with
		2539	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2540	enabled.
1959		2541
1960		2542
1961	=head1 BUGS	2543	=head1 BUGS
1962		2544
1963	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2545	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
…		…
1975	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2557	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1976		2558
1977	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2559	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1978	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2560	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1979	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2561	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1980	L<AnyEvent::Impl::POE>.	2562	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1981		2563
1982	Non-blocking file handles, sockets, TCP clients and	2564	Non-blocking file handles, sockets, TCP clients and
1983	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2565	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1984		2566
1985	Asynchronous DNS: L<AnyEvent::DNS>.	2567	Asynchronous DNS: L<AnyEvent::DNS>.
1986		2568
1987	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2569	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2570	L<Coro::Event>,
1988		2571
1989	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2572	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2573	L<AnyEvent::HTTP>.
1990		2574
1991		2575
1992	=head1 AUTHOR	2576	=head1 AUTHOR
1993		2577
1994	Marc Lehmann <schmorp@schmorp.de>	2578	Marc Lehmann <schmorp@schmorp.de>

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