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Revision 1.202 by root, Wed Apr 1 15:29:00 2009 UTC vs.
Revision 1.272 by root, Thu Aug 6 13:31:01 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, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
		6	and POE are various supported event loops/environments.
6		7
7	=head1 SYNOPSIS	8	=head1 SYNOPSIS
8		9
9	use AnyEvent;	10	use AnyEvent;
10		11
		12	# file descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { ... });	13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
12		14
		15	# one-shot or repeating timers
13	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
14	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
15		18
16	print AnyEvent->now; # prints current event loop time	19	print AnyEvent->now; # prints current event loop time
17	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
18		21
		22	# POSIX signal
19	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });	23	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
20		24
		25	# child process exit
21	my $w = AnyEvent->child (pid => $pid, cb => sub {	26	my $w = AnyEvent->child (pid => $pid, cb => sub {
22	my ($pid, $status) = @_;	27	my ($pid, $status) = @_;
23	...	28	...
24	});	29	});
		30
		31	# called when event loop idle (if applicable)
		32	my $w = AnyEvent->idle (cb => sub { ... });
25		33
26	my $w = AnyEvent->condvar; # stores whether a condition was flagged	34	my $w = AnyEvent->condvar; # stores whether a condition was flagged
27	$w->send; # wake up current and all future recv's	35	$w->send; # wake up current and all future recv's
28	$w->recv; # enters "main loop" till $condvar gets ->send	36	$w->recv; # enters "main loop" till $condvar gets ->send
29	# use a condvar in callback mode:	37	# use a condvar in callback mode:
…		…
32	=head1 INTRODUCTION/TUTORIAL	40	=head1 INTRODUCTION/TUTORIAL
33		41
34	This manpage is mainly a reference manual. If you are interested	42	This manpage is mainly a reference manual. If you are interested
35	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
36	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.
37		53
38	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	54	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
39		55
40	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
41	nowadays. So what is different about AnyEvent?	57	nowadays. So what is different about AnyEvent?
…		…
165	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
166	declared.	182	declared.
167		183
168	=head2 I/O WATCHERS	184	=head2 I/O WATCHERS
169		185
		186	$w = AnyEvent->io (
		187	fh => <filehandle_or_fileno>,
		188	poll => <"r" or "w">,
		189	cb => <callback>,
		190	);
		191
170	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
171	with the following mandatory key-value pairs as arguments:	193	with the following mandatory key-value pairs as arguments:
172		194
173	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
174	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
175	handle). Note that only file handles pointing to things for which	197	handle). Note that only file handles pointing to things for which
176	non-blocking operation makes sense are allowed. This includes sockets,	198	non-blocking operation makes sense are allowed. This includes sockets,
177	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
178	or block devices.	200	or block devices.
…		…
203	undef $w;	225	undef $w;
204	});	226	});
205		227
206	=head2 TIME WATCHERS	228	=head2 TIME WATCHERS
207		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
208	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 >>
209	method with the following mandatory arguments:	239	method with the following mandatory arguments:
210		240
211	C<after> specifies after how many seconds (fractional values are	241	C<after> specifies after how many seconds (fractional values are
212	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
…		…
320	In either case, if you care (and in most cases, you don't), then you	350	In either case, if you care (and in most cases, you don't), then you
321	can get whatever behaviour you want with any event loop, by taking the	351	can get whatever behaviour you want with any event loop, by taking the
322	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	352	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
323	account.	353	account.
324		354
		355	=item AnyEvent->now_update
		356
		357	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		358	the current time for each loop iteration (see the discussion of L<<
		359	AnyEvent->now >>, above).
		360
		361	When a callback runs for a long time (or when the process sleeps), then
		362	this "current" time will differ substantially from the real time, which
		363	might affect timers and time-outs.
		364
		365	When this is the case, you can call this method, which will update the
		366	event loop's idea of "current time".
		367
		368	Note that updating the time I<might> cause some events to be handled.
		369
325	=back	370	=back
326		371
327	=head2 SIGNAL WATCHERS	372	=head2 SIGNAL WATCHERS
		373
		374	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
328		375
329	You can watch for signals using a signal watcher, C<signal> is the signal	376	You can watch for signals using a signal watcher, C<signal> is the signal
330	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	377	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
331	callback to be invoked whenever a signal occurs.	378	callback to be invoked whenever a signal occurs.
332		379
…		…
338	invocation, and callback invocation will be synchronous. Synchronous means	385	invocation, and callback invocation will be synchronous. Synchronous means
339	that it might take a while until the signal gets handled by the process,	386	that it might take a while until the signal gets handled by the process,
340	but it is guaranteed not to interrupt any other callbacks.	387	but it is guaranteed not to interrupt any other callbacks.
341		388
342	The main advantage of using these watchers is that you can share a signal	389	The main advantage of using these watchers is that you can share a signal
343	between multiple watchers.	390	between multiple watchers, and AnyEvent will ensure that signals will not
		391	interrupt your program at bad times.
344		392
345	This watcher might use C<%SIG>, so programs overwriting those signals	393	This watcher might use C<%SIG> (depending on the event loop used),
346	directly will likely not work correctly.	394	so programs overwriting those signals directly will likely not work
		395	correctly.
347		396
348	Example: exit on SIGINT	397	Example: exit on SIGINT
349		398
350	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	399	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
351		400
		401	=head3 Signal Races, Delays and Workarounds
		402
		403	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		404	callbacks to signals in a generic way, which is a pity, as you cannot
		405	do race-free signal handling in perl, requiring C libraries for
		406	this. AnyEvent will try to do it's best, which means in some cases,
		407	signals will be delayed. The maximum time a signal might be delayed is
		408	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		409	variable can be changed only before the first signal watcher is created,
		410	and should be left alone otherwise. This variable determines how often
		411	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		412	will cause fewer spurious wake-ups, which is better for power and CPU
		413	saving.
		414
		415	All these problems can be avoided by installing the optional
		416	L<Async::Interrupt> module, which works with most event loops. It will not
		417	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		418	(and not with L<POE> currently, as POE does it's own workaround with
		419	one-second latency). For those, you just have to suffer the delays.
		420
352	=head2 CHILD PROCESS WATCHERS	421	=head2 CHILD PROCESS WATCHERS
353		422
		423	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		424
354	You can also watch on a child process exit and catch its exit status.	425	You can also watch on a child process exit and catch its exit status.
355		426
356	The child process is specified by the C<pid> argument (if set to C<0>, it	427	The child process is specified by the C<pid> argument (one some backends,
357	watches for any child process exit). The watcher will triggered only when	428	using C<0> watches for any child process exit, on others this will
358	the child process has finished and an exit status is available, not on	429	croak). The watcher will be triggered only when the child process has
359	any trace events (stopped/continued).	430	finished and an exit status is available, not on any trace events
		431	(stopped/continued).
360		432
361	The callback will be called with the pid and exit status (as returned by	433	The callback will be called with the pid and exit status (as returned by
362	waitpid), so unlike other watcher types, you I<can> rely on child watcher	434	waitpid), so unlike other watcher types, you I<can> rely on child watcher
363	callback arguments.	435	callback arguments.
364		436
…		…
369		441
370	There is a slight catch to child watchers, however: you usually start them	442	There is a slight catch to child watchers, however: you usually start them
371	I<after> the child process was created, and this means the process could	443	I<after> the child process was created, and this means the process could
372	have exited already (and no SIGCHLD will be sent anymore).	444	have exited already (and no SIGCHLD will be sent anymore).
373		445
374	Not all event models handle this correctly (POE doesn't), but even for	446	Not all event models handle this correctly (neither POE nor IO::Async do,
		447	see their AnyEvent::Impl manpages for details), but even for event models
375	event models that I<do> handle this correctly, they usually need to be	448	that I<do> handle this correctly, they usually need to be loaded before
376	loaded before the process exits (i.e. before you fork in the first place).	449	the process exits (i.e. before you fork in the first place). AnyEvent's
		450	pure perl event loop handles all cases correctly regardless of when you
		451	start the watcher.
377		452
378	This means you cannot create a child watcher as the very first thing in an	453	This means you cannot create a child watcher as the very first
379	AnyEvent program, you I<have> to create at least one watcher before you	454	thing in an AnyEvent program, you I<have> to create at least one
380	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	455	watcher before you C<fork> the child (alternatively, you can call
		456	C<AnyEvent::detect>).
		457
		458	As most event loops do not support waiting for child events, they will be
		459	emulated by AnyEvent in most cases, in which the latency and race problems
		460	mentioned in the description of signal watchers apply.
381		461
382	Example: fork a process and wait for it	462	Example: fork a process and wait for it
383		463
384	my $done = AnyEvent->condvar;	464	my $done = AnyEvent->condvar;
385		465
…		…
395	);	475	);
396		476
397	# do something else, then wait for process exit	477	# do something else, then wait for process exit
398	$done->recv;	478	$done->recv;
399		479
		480	=head2 IDLE WATCHERS
		481
		482	$w = AnyEvent->idle (cb => <callback>);
		483
		484	Sometimes there is a need to do something, but it is not so important
		485	to do it instantly, but only when there is nothing better to do. This
		486	"nothing better to do" is usually defined to be "no other events need
		487	attention by the event loop".
		488
		489	Idle watchers ideally get invoked when the event loop has nothing
		490	better to do, just before it would block the process to wait for new
		491	events. Instead of blocking, the idle watcher is invoked.
		492
		493	Most event loops unfortunately do not really support idle watchers (only
		494	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		495	will simply call the callback "from time to time".
		496
		497	Example: read lines from STDIN, but only process them when the
		498	program is otherwise idle:
		499
		500	my @lines; # read data
		501	my $idle_w;
		502	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		503	push @lines, scalar <STDIN>;
		504
		505	# start an idle watcher, if not already done
		506	$idle_w ||= AnyEvent->idle (cb => sub {
		507	# handle only one line, when there are lines left
		508	if (my $line = shift @lines) {
		509	print "handled when idle: $line";
		510	} else {
		511	# otherwise disable the idle watcher again
		512	undef $idle_w;
		513	}
		514	});
		515	});
		516
400	=head2 CONDITION VARIABLES	517	=head2 CONDITION VARIABLES
		518
		519	$cv = AnyEvent->condvar;
		520
		521	$cv->send (<list>);
		522	my @res = $cv->recv;
401		523
402	If you are familiar with some event loops you will know that all of them	524	If you are familiar with some event loops you will know that all of them
403	require you to run some blocking "loop", "run" or similar function that	525	require you to run some blocking "loop", "run" or similar function that
404	will actively watch for new events and call your callbacks.	526	will actively watch for new events and call your callbacks.
405		527
406	AnyEvent is different, it expects somebody else to run the event loop and	528	AnyEvent is slightly different: it expects somebody else to run the event
407	will only block when necessary (usually when told by the user).	529	loop and will only block when necessary (usually when told by the user).
408		530
409	The instrument to do that is called a "condition variable", so called	531	The instrument to do that is called a "condition variable", so called
410	because they represent a condition that must become true.	532	because they represent a condition that must become true.
411		533
		534	Now is probably a good time to look at the examples further below.
		535
412	Condition variables can be created by calling the C<< AnyEvent->condvar	536	Condition variables can be created by calling the C<< AnyEvent->condvar
413	>> method, usually without arguments. The only argument pair allowed is	537	>> method, usually without arguments. The only argument pair allowed is
414
415	C<cb>, which specifies a callback to be called when the condition variable	538	C<cb>, which specifies a callback to be called when the condition variable
416	becomes true, with the condition variable as the first argument (but not	539	becomes true, with the condition variable as the first argument (but not
417	the results).	540	the results).
418		541
419	After creation, the condition variable is "false" until it becomes "true"	542	After creation, the condition variable is "false" until it becomes "true"
…		…
424	Condition variables are similar to callbacks, except that you can	547	Condition variables are similar to callbacks, except that you can
425	optionally wait for them. They can also be called merge points - points	548	optionally wait for them. They can also be called merge points - points
426	in time where multiple outstanding events have been processed. And yet	549	in time where multiple outstanding events have been processed. And yet
427	another way to call them is transactions - each condition variable can be	550	another way to call them is transactions - each condition variable can be
428	used to represent a transaction, which finishes at some point and delivers	551	used to represent a transaction, which finishes at some point and delivers
429	a result.	552	a result. And yet some people know them as "futures" - a promise to
		553	compute/deliver something that you can wait for.
430		554
431	Condition variables are very useful to signal that something has finished,	555	Condition variables are very useful to signal that something has finished,
432	for example, if you write a module that does asynchronous http requests,	556	for example, if you write a module that does asynchronous http requests,
433	then a condition variable would be the ideal candidate to signal the	557	then a condition variable would be the ideal candidate to signal the
434	availability of results. The user can either act when the callback is	558	availability of results. The user can either act when the callback is
…		…
468	after => 1,	592	after => 1,
469	cb => sub { $result_ready->send },	593	cb => sub { $result_ready->send },
470	);	594	);
471		595
472	# this "blocks" (while handling events) till the callback	596	# this "blocks" (while handling events) till the callback
473	# calls send	597	# calls -<send
474	$result_ready->recv;	598	$result_ready->recv;
475		599
476	Example: wait for a timer, but take advantage of the fact that	600	Example: wait for a timer, but take advantage of the fact that condition
477	condition variables are also code references.	601	variables are also callable directly.
478		602
479	my $done = AnyEvent->condvar;	603	my $done = AnyEvent->condvar;
480	my $delay = AnyEvent->timer (after => 5, cb => $done);	604	my $delay = AnyEvent->timer (after => 5, cb => $done);
481	$done->recv;	605	$done->recv;
482		606
…		…
488		612
489	...	613	...
490		614
491	my @info = $couchdb->info->recv;	615	my @info = $couchdb->info->recv;
492		616
493	And this is how you would just ste a callback to be called whenever the	617	And this is how you would just set a callback to be called whenever the
494	results are available:	618	results are available:
495		619
496	$couchdb->info->cb (sub {	620	$couchdb->info->cb (sub {
497	my @info = $_[0]->recv;	621	my @info = $_[0]->recv;
498	});	622	});
…		…
516	immediately from within send.	640	immediately from within send.
517		641
518	Any arguments passed to the C<send> call will be returned by all	642	Any arguments passed to the C<send> call will be returned by all
519	future C<< ->recv >> calls.	643	future C<< ->recv >> calls.
520		644
521	Condition variables are overloaded so one can call them directly	645	Condition variables are overloaded so one can call them directly (as if
522	(as a code reference). Calling them directly is the same as calling	646	they were a code reference). Calling them directly is the same as calling
523	C<send>. Note, however, that many C-based event loops do not handle	647	C<send>.
524	overloading, so as tempting as it may be, passing a condition variable
525	instead of a callback does not work. Both the pure perl and EV loops
526	support overloading, however, as well as all functions that use perl to
527	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
528	example).
529		648
530	=item $cv->croak ($error)	649	=item $cv->croak ($error)
531		650
532	Similar to send, but causes all call's to C<< ->recv >> to invoke	651	Similar to send, but causes all call's to C<< ->recv >> to invoke
533	C<Carp::croak> with the given error message/object/scalar.	652	C<Carp::croak> with the given error message/object/scalar.
534		653
535	This can be used to signal any errors to the condition variable	654	This can be used to signal any errors to the condition variable
536	user/consumer.	655	user/consumer. Doing it this way instead of calling C<croak> directly
		656	delays the error detetcion, but has the overwhelmign advantage that it
		657	diagnoses the error at the place where the result is expected, and not
		658	deep in some event clalback without connection to the actual code causing
		659	the problem.
537		660
538	=item $cv->begin ([group callback])	661	=item $cv->begin ([group callback])
539		662
540	=item $cv->end	663	=item $cv->end
541
542	These two methods are EXPERIMENTAL and MIGHT CHANGE.
543		664
544	These two methods can be used to combine many transactions/events into	665	These two methods can be used to combine many transactions/events into
545	one. For example, a function that pings many hosts in parallel might want	666	one. For example, a function that pings many hosts in parallel might want
546	to use a condition variable for the whole process.	667	to use a condition variable for the whole process.
547		668
…		…
549	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	670	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
550	>>, the (last) callback passed to C<begin> will be executed. That callback	671	>>, the (last) callback passed to C<begin> will be executed. That callback
551	is I<supposed> to call C<< ->send >>, but that is not required. If no	672	is I<supposed> to call C<< ->send >>, but that is not required. If no
552	callback was set, C<send> will be called without any arguments.	673	callback was set, C<send> will be called without any arguments.
553		674
554	Let's clarify this with the ping example:	675	You can think of C<< $cv->send >> giving you an OR condition (one call
		676	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		677	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		678
		679	Let's start with a simple example: you have two I/O watchers (for example,
		680	STDOUT and STDERR for a program), and you want to wait for both streams to
		681	close before activating a condvar:
		682
		683	my $cv = AnyEvent->condvar;
		684
		685	$cv->begin; # first watcher
		686	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		687	defined sysread $fh1, my $buf, 4096
		688	or $cv->end;
		689	});
		690
		691	$cv->begin; # second watcher
		692	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		693	defined sysread $fh2, my $buf, 4096
		694	or $cv->end;
		695	});
		696
		697	$cv->recv;
		698
		699	This works because for every event source (EOF on file handle), there is
		700	one call to C<begin>, so the condvar waits for all calls to C<end> before
		701	sending.
		702
		703	The ping example mentioned above is slightly more complicated, as the
		704	there are results to be passwd back, and the number of tasks that are
		705	begung can potentially be zero:
555		706
556	my $cv = AnyEvent->condvar;	707	my $cv = AnyEvent->condvar;
557		708
558	my %result;	709	my %result;
559	$cv->begin (sub { $cv->send (\%result) });	710	$cv->begin (sub { $cv->send (\%result) });
…		…
579	loop, which serves two important purposes: first, it sets the callback	730	loop, which serves two important purposes: first, it sets the callback
580	to be called once the counter reaches C<0>, and second, it ensures that	731	to be called once the counter reaches C<0>, and second, it ensures that
581	C<send> is called even when C<no> hosts are being pinged (the loop	732	C<send> is called even when C<no> hosts are being pinged (the loop
582	doesn't execute once).	733	doesn't execute once).
583		734
584	This is the general pattern when you "fan out" into multiple subrequests:	735	This is the general pattern when you "fan out" into multiple (but
585	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	736	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
586	is called at least once, and then, for each subrequest you start, call	737	the callback and ensure C<end> is called at least once, and then, for each
587	C<begin> and for each subrequest you finish, call C<end>.	738	subrequest you start, call C<begin> and for each subrequest you finish,
		739	call C<end>.
588		740
589	=back	741	=back
590		742
591	=head3 METHODS FOR CONSUMERS	743	=head3 METHODS FOR CONSUMERS
592		744
…		…
608	function will call C<croak>.	760	function will call C<croak>.
609		761
610	In list context, all parameters passed to C<send> will be returned,	762	In list context, all parameters passed to C<send> will be returned,
611	in scalar context only the first one will be returned.	763	in scalar context only the first one will be returned.
612		764
		765	Note that doing a blocking wait in a callback is not supported by any
		766	event loop, that is, recursive invocation of a blocking C<< ->recv
		767	>> is not allowed, and the C<recv> call will C<croak> if such a
		768	condition is detected. This condition can be slightly loosened by using
		769	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		770	any thread that doesn't run the event loop itself.
		771
613	Not all event models support a blocking wait - some die in that case	772	Not all event models support a blocking wait - some die in that case
614	(programs might want to do that to stay interactive), so I<if you are	773	(programs might want to do that to stay interactive), so I<if you are
615	using this from a module, never require a blocking wait>, but let the	774	using this from a module, never require a blocking wait>. Instead, let the
616	caller decide whether the call will block or not (for example, by coupling	775	caller decide whether the call will block or not (for example, by coupling
617	condition variables with some kind of request results and supporting	776	condition variables with some kind of request results and supporting
618	callbacks so the caller knows that getting the result will not block,	777	callbacks so the caller knows that getting the result will not block,
619	while still supporting blocking waits if the caller so desires).	778	while still supporting blocking waits if the caller so desires).
620		779
621	Another reason I<never> to C<< ->recv >> in a module is that you cannot
622	sensibly have two C<< ->recv >>'s in parallel, as that would require
623	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
624	can supply.
625
626	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
627	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
628	versions and also integrates coroutines into AnyEvent, making blocking
629	C<< ->recv >> calls perfectly safe as long as they are done from another
630	coroutine (one that doesn't run the event loop).
631
632	You can ensure that C<< -recv >> never blocks by setting a callback and	780	You can ensure that C<< -recv >> never blocks by setting a callback and
633	only calling C<< ->recv >> from within that callback (or at a later	781	only calling C<< ->recv >> from within that callback (or at a later
634	time). This will work even when the event loop does not support blocking	782	time). This will work even when the event loop does not support blocking
635	waits otherwise.	783	waits otherwise.
636		784
…		…
642	=item $cb = $cv->cb ($cb->($cv))	790	=item $cb = $cv->cb ($cb->($cv))
643		791
644	This is a mutator function that returns the callback set and optionally	792	This is a mutator function that returns the callback set and optionally
645	replaces it before doing so.	793	replaces it before doing so.
646		794
647	The callback will be called when the condition becomes "true", i.e. when	795	The callback will be called when the condition becomes (or already was)
648	C<send> or C<croak> are called, with the only argument being the condition	796	"true", i.e. when C<send> or C<croak> are called (or were called), with
649	variable itself. Calling C<recv> inside the callback or at any later time	797	the only argument being the condition variable itself. Calling C<recv>
650	is guaranteed not to block.	798	inside the callback or at any later time is guaranteed not to block.
651		799
652	=back	800	=back
653		801
		802	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		803
		804	The available backend classes are (every class has its own manpage):
		805
		806	=over 4
		807
		808	=item Backends that are autoprobed when no other event loop can be found.
		809
		810	EV is the preferred backend when no other event loop seems to be in
		811	use. If EV is not installed, then AnyEvent will try Event, and, failing
		812	that, will fall back to its own pure-perl implementation, which is
		813	available everywhere as it comes with AnyEvent itself.
		814
		815	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		816	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		817	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		818
		819	=item Backends that are transparently being picked up when they are used.
		820
		821	These will be used when they are currently loaded when the first watcher
		822	is created, in which case it is assumed that the application is using
		823	them. This means that AnyEvent will automatically pick the right backend
		824	when the main program loads an event module before anything starts to
		825	create watchers. Nothing special needs to be done by the main program.
		826
		827	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		828	AnyEvent::Impl::Tk based on Tk, very broken.
		829	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		830	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		831	AnyEvent::Impl::Irssi used when running within irssi.
		832
		833	=item Backends with special needs.
		834
		835	Qt requires the Qt::Application to be instantiated first, but will
		836	otherwise be picked up automatically. As long as the main program
		837	instantiates the application before any AnyEvent watchers are created,
		838	everything should just work.
		839
		840	AnyEvent::Impl::Qt based on Qt.
		841
		842	Support for IO::Async can only be partial, as it is too broken and
		843	architecturally limited to even support the AnyEvent API. It also
		844	is the only event loop that needs the loop to be set explicitly, so
		845	it can only be used by a main program knowing about AnyEvent. See
		846	L<AnyEvent::Impl::Async> for the gory details.
		847
		848	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		849
		850	=item Event loops that are indirectly supported via other backends.
		851
		852	Some event loops can be supported via other modules:
		853
		854	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		855
		856	B<WxWidgets> has no support for watching file handles. However, you can
		857	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		858	polls 20 times per second, which was considered to be too horrible to even
		859	consider for AnyEvent.
		860
		861	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		862	backend, so it can be supported through POE.
		863
		864	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		865	load L<POE> when detecting them, in the hope that POE will pick them up,
		866	in which case everything will be automatic.
		867
		868	=back
		869
654	=head1 GLOBAL VARIABLES AND FUNCTIONS	870	=head1 GLOBAL VARIABLES AND FUNCTIONS
655		871
		872	These are not normally required to use AnyEvent, but can be useful to
		873	write AnyEvent extension modules.
		874
656	=over 4	875	=over 4
657		876
658	=item $AnyEvent::MODEL	877	=item $AnyEvent::MODEL
659		878
660	Contains C<undef> until the first watcher is being created. Then it	879	Contains C<undef> until the first watcher is being created, before the
		880	backend has been autodetected.
		881
661	contains the event model that is being used, which is the name of the	882	Afterwards it contains the event model that is being used, which is the
662	Perl class implementing the model. This class is usually one of the	883	name of the Perl class implementing the model. This class is usually one
663	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	884	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
664	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	885	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
665		886	will be C<urxvt::anyevent>).
666	The known classes so far are:
667
668	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
669	AnyEvent::Impl::Event based on Event, second best choice.
670	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
671	AnyEvent::Impl::Glib based on Glib, third-best choice.
672	AnyEvent::Impl::Tk based on Tk, very bad choice.
673	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
674	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
675	AnyEvent::Impl::POE based on POE, not generic enough for full support.
676
677	There is no support for WxWidgets, as WxWidgets has no support for
678	watching file handles. However, you can use WxWidgets through the
679	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
680	second, which was considered to be too horrible to even consider for
681	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
682	it's adaptor.
683
684	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
685	autodetecting them.
686		887
687	=item AnyEvent::detect	888	=item AnyEvent::detect
688		889
689	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	890	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
690	if necessary. You should only call this function right before you would	891	if necessary. You should only call this function right before you would
691	have created an AnyEvent watcher anyway, that is, as late as possible at	892	have created an AnyEvent watcher anyway, that is, as late as possible at
692	runtime.	893	runtime, and not e.g. while initialising of your module.
		894
		895	If you need to do some initialisation before AnyEvent watchers are
		896	created, use C<post_detect>.
693		897
694	=item $guard = AnyEvent::post_detect { BLOCK }	898	=item $guard = AnyEvent::post_detect { BLOCK }
695		899
696	Arranges for the code block to be executed as soon as the event model is	900	Arranges for the code block to be executed as soon as the event model is
697	autodetected (or immediately if this has already happened).	901	autodetected (or immediately if this has already happened).
698		902
		903	The block will be executed I<after> the actual backend has been detected
		904	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		905	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		906	other initialisations - see the sources of L<AnyEvent::Strict> or
		907	L<AnyEvent::AIO> to see how this is used.
		908
		909	The most common usage is to create some global watchers, without forcing
		910	event module detection too early, for example, L<AnyEvent::AIO> creates
		911	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		912	avoid autodetecting the event module at load time.
		913
699	If called in scalar or list context, then it creates and returns an object	914	If called in scalar or list context, then it creates and returns an object
700	that automatically removes the callback again when it is destroyed. See	915	that automatically removes the callback again when it is destroyed (or
		916	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
701	L<Coro::BDB> for a case where this is useful.	917	a case where this is useful.
		918
		919	Example: Create a watcher for the IO::AIO module and store it in
		920	C<$WATCHER>. Only do so after the event loop is initialised, though.
		921
		922	our WATCHER;
		923
		924	my $guard = AnyEvent::post_detect {
		925	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		926	};
		927
		928	# the ||= is important in case post_detect immediately runs the block,
		929	# as to not clobber the newly-created watcher. assigning both watcher and
		930	# post_detect guard to the same variable has the advantage of users being
		931	# able to just C<undef $WATCHER> if the watcher causes them grief.
		932
		933	$WATCHER ||= $guard;
702		934
703	=item @AnyEvent::post_detect	935	=item @AnyEvent::post_detect
704		936
705	If there are any code references in this array (you can C<push> to it	937	If there are any code references in this array (you can C<push> to it
706	before or after loading AnyEvent), then they will called directly after	938	before or after loading AnyEvent), then they will called directly after
707	the event loop has been chosen.	939	the event loop has been chosen.
708		940
709	You should check C<$AnyEvent::MODEL> before adding to this array, though:	941	You should check C<$AnyEvent::MODEL> before adding to this array, though:
710	if it contains a true value then the event loop has already been detected,	942	if it is defined then the event loop has already been detected, and the
711	and the array will be ignored.	943	array will be ignored.
712		944
713	Best use C<AnyEvent::post_detect { BLOCK }> instead.	945	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		946	it,as it takes care of these details.
		947
		948	This variable is mainly useful for modules that can do something useful
		949	when AnyEvent is used and thus want to know when it is initialised, but do
		950	not need to even load it by default. This array provides the means to hook
		951	into AnyEvent passively, without loading it.
714		952
715	=back	953	=back
716		954
717	=head1 WHAT TO DO IN A MODULE	955	=head1 WHAT TO DO IN A MODULE
718		956
…		…
773		1011
774		1012
775	=head1 OTHER MODULES	1013	=head1 OTHER MODULES
776		1014
777	The following is a non-exhaustive list of additional modules that use	1015	The following is a non-exhaustive list of additional modules that use
778	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1016	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
779	in the same program. Some of the modules come with AnyEvent, some are	1017	modules and other event loops in the same program. Some of the modules
780	available via CPAN.	1018	come with AnyEvent, most are available via CPAN.
781		1019
782	=over 4	1020	=over 4
783		1021
784	=item L<AnyEvent::Util>	1022	=item L<AnyEvent::Util>
785		1023
…		…
794		1032
795	=item L<AnyEvent::Handle>	1033	=item L<AnyEvent::Handle>
796		1034
797	Provide read and write buffers, manages watchers for reads and writes,	1035	Provide read and write buffers, manages watchers for reads and writes,
798	supports raw and formatted I/O, I/O queued and fully transparent and	1036	supports raw and formatted I/O, I/O queued and fully transparent and
799	non-blocking SSL/TLS.	1037	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
800		1038
801	=item L<AnyEvent::DNS>	1039	=item L<AnyEvent::DNS>
802		1040
803	Provides rich asynchronous DNS resolver capabilities.	1041	Provides rich asynchronous DNS resolver capabilities.
804		1042
…		…
832		1070
833	=item L<AnyEvent::GPSD>	1071	=item L<AnyEvent::GPSD>
834		1072
835	A non-blocking interface to gpsd, a daemon delivering GPS information.	1073	A non-blocking interface to gpsd, a daemon delivering GPS information.
836		1074
		1075	=item L<AnyEvent::IRC>
		1076
		1077	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1078
		1079	=item L<AnyEvent::XMPP>
		1080
		1081	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1082	Net::XMPP2>.
		1083
837	=item L<AnyEvent::IGS>	1084	=item L<AnyEvent::IGS>
838		1085
839	A non-blocking interface to the Internet Go Server protocol (used by	1086	A non-blocking interface to the Internet Go Server protocol (used by
840	L<App::IGS>).	1087	L<App::IGS>).
841		1088
842	=item L<AnyEvent::IRC>
843
844	AnyEvent based IRC client module family (replacing the older Net::IRC3).
845
846	=item L<Net::XMPP2>
847
848	AnyEvent based XMPP (Jabber protocol) module family.
849
850	=item L<Net::FCP>	1089	=item L<Net::FCP>
851		1090
852	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1091	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
853	of AnyEvent.	1092	of AnyEvent.
854		1093
…		…
858		1097
859	=item L<Coro>	1098	=item L<Coro>
860		1099
861	Has special support for AnyEvent via L<Coro::AnyEvent>.	1100	Has special support for AnyEvent via L<Coro::AnyEvent>.
862		1101
863	=item L<IO::Lambda>
864
865	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
866
867	=back	1102	=back
868		1103
869	=cut	1104	=cut
870		1105
871	package AnyEvent;	1106	package AnyEvent;
872		1107
		1108	# basically a tuned-down version of common::sense
		1109	sub common_sense {
873	no warnings;	1110	# no warnings
		1111	${^WARNING_BITS} ^= ${^WARNING_BITS};
874	use strict qw(vars subs);	1112	# use strict vars subs
		1113	$^H |= 0x00000600;
		1114	}
875		1115
		1116	BEGIN { AnyEvent::common_sense }
		1117
876	use Carp;	1118	use Carp ();
877		1119
878	our $VERSION = 4.35;	1120	our $VERSION = 4.901;
879	our $MODEL;	1121	our $MODEL;
880		1122
881	our $AUTOLOAD;	1123	our $AUTOLOAD;
882	our @ISA;	1124	our @ISA;
883		1125
884	our @REGISTRY;	1126	our @REGISTRY;
885		1127
886	our $WIN32;	1128	our $WIN32;
887		1129
		1130	our $VERBOSE;
		1131
888	BEGIN {	1132	BEGIN {
889	my $win32 = ! ! ($^O =~ /mswin32/i);	1133	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
890	eval "sub WIN32(){ $win32 }";	1134	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
891	}
892		1135
		1136	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1137	if ${^TAINT};
		1138
893	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1139	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1140
		1141	}
		1142
		1143	our $MAX_SIGNAL_LATENCY = 10;
894		1144
895	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1145	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
896		1146
897	{	1147	{
898	my $idx;	1148	my $idx;
…		…
900	for reverse split /\s*,\s*/,	1150	for reverse split /\s*,\s*/,
901	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1151	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
902	}	1152	}
903		1153
904	my @models = (	1154	my @models = (
905	[EV:: => AnyEvent::Impl::EV::],	1155	[EV:: => AnyEvent::Impl::EV:: , 1],
906	[Event:: => AnyEvent::Impl::Event::],	1156	[Event:: => AnyEvent::Impl::Event::, 1],
907	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1157	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
908	# everything below here will not be autoprobed	1158	# everything below here will not (normally) be autoprobed
909	# as the pureperl backend should work everywhere	1159	# as the pureperl backend should work everywhere
910	# and is usually faster	1160	# and is usually faster
		1161	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1162	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1163	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
911	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1164	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
912	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
913	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
914	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1165	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
915	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1166	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
916	[Wx:: => AnyEvent::Impl::POE::],	1167	[Wx:: => AnyEvent::Impl::POE::],
917	[Prima:: => AnyEvent::Impl::POE::],	1168	[Prima:: => AnyEvent::Impl::POE::],
		1169	# IO::Async is just too broken - we would need workarounds for its
		1170	# byzantine signal and broken child handling, among others.
		1171	# IO::Async is rather hard to detect, as it doesn't have any
		1172	# obvious default class.
		1173	# [0, IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1174	# [0, IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1175	# [0, IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
918	);	1176	);
919		1177
920	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1178	our %method = map +($_ => 1),
		1179	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
921		1180
922	our @post_detect;	1181	our @post_detect;
923		1182
924	sub post_detect(&) {	1183	sub post_detect(&) {
925	my ($cb) = @_;	1184	my ($cb) = @_;
926		1185
927	if ($MODEL) {	1186	if ($MODEL) {
928	$cb->();	1187	$cb->();
929		1188
930	1	1189	undef
931	} else {	1190	} else {
932	push @post_detect, $cb;	1191	push @post_detect, $cb;
933		1192
934	defined wantarray	1193	defined wantarray
935	? bless \$cb, "AnyEvent::Util::PostDetect"	1194	? bless \$cb, "AnyEvent::Util::postdetect"
936	: ()	1195	: ()
937	}	1196	}
938	}	1197	}
939		1198
940	sub AnyEvent::Util::PostDetect::DESTROY {	1199	sub AnyEvent::Util::postdetect::DESTROY {
941	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1200	@post_detect = grep $_ != ${$_[0]}, @post_detect;
942	}	1201	}
943		1202
944	sub detect() {	1203	sub detect() {
945	unless ($MODEL) {	1204	unless ($MODEL) {
946	no strict 'refs';
947	local $SIG{__DIE__};	1205	local $SIG{__DIE__};
948		1206
949	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1207	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
950	my $model = "AnyEvent::Impl::$1";	1208	my $model = "AnyEvent::Impl::$1";
951	if (eval "require $model") {	1209	if (eval "require $model") {
952	$MODEL = $model;	1210	$MODEL = $model;
953	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1211	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
954	} else {	1212	} else {
955	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1213	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
956	}	1214	}
957	}	1215	}
958		1216
959	# check for already loaded models	1217	# check for already loaded models
960	unless ($MODEL) {	1218	unless ($MODEL) {
961	for (@REGISTRY, @models) {	1219	for (@REGISTRY, @models) {
962	my ($package, $model) = @$_;	1220	my ($package, $model) = @$_;
963	if (${"$package\::VERSION"} > 0) {	1221	if (${"$package\::VERSION"} > 0) {
964	if (eval "require $model") {	1222	if (eval "require $model") {
965	$MODEL = $model;	1223	$MODEL = $model;
966	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1224	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
967	last;	1225	last;
968	}	1226	}
969	}	1227	}
970	}	1228	}
971		1229
972	unless ($MODEL) {	1230	unless ($MODEL) {
973	# try to load a model	1231	# try to autoload a model
974
975	for (@REGISTRY, @models) {	1232	for (@REGISTRY, @models) {
976	my ($package, $model) = @$_;	1233	my ($package, $model, $autoload) = @$_;
		1234	if (
		1235	$autoload
977	if (eval "require $package"	1236	and eval "require $package"
978	and ${"$package\::VERSION"} > 0	1237	and ${"$package\::VERSION"} > 0
979	and eval "require $model") {	1238	and eval "require $model"
		1239	) {
980	$MODEL = $model;	1240	$MODEL = $model;
981	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1241	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
982	last;	1242	last;
983	}	1243	}
984	}	1244	}
985		1245
986	$MODEL	1246	$MODEL
987	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1247	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
988	}	1248	}
989	}	1249	}
990		1250
991	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1251	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
992		1252
…		…
1002		1262
1003	sub AUTOLOAD {	1263	sub AUTOLOAD {
1004	(my $func = $AUTOLOAD) =~ s/.*://;	1264	(my $func = $AUTOLOAD) =~ s/.*://;
1005		1265
1006	$method{$func}	1266	$method{$func}
1007	or croak "$func: not a valid method for AnyEvent objects";	1267	or Carp::croak "$func: not a valid method for AnyEvent objects";
1008		1268
1009	detect unless $MODEL;	1269	detect unless $MODEL;
1010		1270
1011	my $class = shift;	1271	my $class = shift;
1012	$class->$func (@_);	1272	$class->$func (@_);
1013	}	1273	}
1014		1274
1015	# utility function to dup a filehandle. this is used by many backends	1275	# utility function to dup a filehandle. this is used by many backends
1016	# to support binding more than one watcher per filehandle (they usually	1276	# to support binding more than one watcher per filehandle (they usually
1017	# allow only one watcher per fd, so we dup it to get a different one).	1277	# allow only one watcher per fd, so we dup it to get a different one).
1018	sub _dupfh($$$$) {	1278	sub _dupfh($$;$$) {
1019	my ($poll, $fh, $r, $w) = @_;	1279	my ($poll, $fh, $r, $w) = @_;
1020		1280
1021	# cygwin requires the fh mode to be matching, unix doesn't	1281	# cygwin requires the fh mode to be matching, unix doesn't
1022	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1282	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1023	: $poll eq "w" ? ($w, ">")
1024	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1025		1283
1026	open my $fh2, "$mode&" . fileno $fh	1284	open my $fh2, $mode, $fh
1027	or die "cannot dup() filehandle: $!";	1285	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1028		1286
1029	# we assume CLOEXEC is already set by perl in all important cases	1287	# we assume CLOEXEC is already set by perl in all important cases
1030		1288
1031	($fh2, $rw)	1289	($fh2, $rw)
1032	}	1290	}
1033		1291
1034	package AnyEvent::Base;	1292	package AnyEvent::Base;
1035		1293
1036	# default implementation for now and time	1294	# default implementations for many methods
1037		1295
1038	BEGIN {	1296	sub _time {
		1297	# probe for availability of Time::HiRes
1039	if (eval "use Time::HiRes (); time (); 1") {	1298	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1299	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1040	*_time = \&Time::HiRes::time;	1300	*_time = \&Time::HiRes::time;
1041	# if (eval "use POSIX (); (POSIX::times())...	1301	# if (eval "use POSIX (); (POSIX::times())...
1042	} else {	1302	} else {
		1303	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1043	*_time = sub { time }; # epic fail	1304	*_time = sub { time }; # epic fail
1044	}	1305	}
		1306
		1307	&_time
1045	}	1308	}
1046		1309
1047	sub time { _time }	1310	sub time { _time }
1048	sub now { _time }	1311	sub now { _time }
		1312	sub now_update { }
1049		1313
1050	# default implementation for ->condvar	1314	# default implementation for ->condvar
1051		1315
1052	sub condvar {	1316	sub condvar {
1053	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1317	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1054	}	1318	}
1055		1319
1056	# default implementation for ->signal	1320	# default implementation for ->signal
1057		1321
		1322	our $HAVE_ASYNC_INTERRUPT;
		1323
		1324	sub _have_async_interrupt() {
		1325	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1326	&& eval "use Async::Interrupt 1.0 (); 1")
		1327	unless defined $HAVE_ASYNC_INTERRUPT;
		1328
		1329	$HAVE_ASYNC_INTERRUPT
		1330	}
		1331
1058	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1332	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1333	our (%SIG_ASY, %SIG_ASY_W);
		1334	our ($SIG_COUNT, $SIG_TW);
1059		1335
1060	sub _signal_exec {	1336	sub _signal_exec {
		1337	$HAVE_ASYNC_INTERRUPT
		1338	? $SIGPIPE_R->drain
1061	sysread $SIGPIPE_R, my $dummy, 4;	1339	: sysread $SIGPIPE_R, my $dummy, 9;
1062		1340
1063	while (%SIG_EV) {	1341	while (%SIG_EV) {
1064	for (keys %SIG_EV) {	1342	for (keys %SIG_EV) {
1065	delete $SIG_EV{$_};	1343	delete $SIG_EV{$_};
1066	$_->() for values %{ $SIG_CB{$_} || {} };	1344	$_->() for values %{ $SIG_CB{$_} || {} };
1067	}	1345	}
1068	}	1346	}
1069	}	1347	}
1070		1348
		1349	# install a dummy wakeup watcher to reduce signal catching latency
		1350	sub _sig_add() {
		1351	unless ($SIG_COUNT++) {
		1352	# try to align timer on a full-second boundary, if possible
		1353	my $NOW = AnyEvent->now;
		1354
		1355	$SIG_TW = AnyEvent->timer (
		1356	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1357	interval => $MAX_SIGNAL_LATENCY,
		1358	cb => sub { }, # just for the PERL_ASYNC_CHECK
		1359	);
		1360	}
		1361	}
		1362
		1363	sub _sig_del {
		1364	undef $SIG_TW
		1365	unless --$SIG_COUNT;
		1366	}
		1367
		1368	our $_sig_name_init; $_sig_name_init = sub {
		1369	eval q{ # poor man's autoloading
		1370	undef $_sig_name_init;
		1371
		1372	if (_have_async_interrupt) {
		1373	*sig2num = \&Async::Interrupt::sig2num;
		1374	*sig2name = \&Async::Interrupt::sig2name;
		1375	} else {
		1376	require Config;
		1377
		1378	my %signame2num;
		1379	@signame2num{ split ' ', $Config::Config{sig_name} }
		1380	= split ' ', $Config::Config{sig_num};
		1381
		1382	my @signum2name;
		1383	@signum2name[values %signame2num] = keys %signame2num;
		1384
		1385	*sig2num = sub($) {
		1386	$_[0] > 0 ? shift : $signame2num{+shift}
		1387	};
		1388	*sig2name = sub ($) {
		1389	$_[0] > 0 ? $signum2name[+shift] : shift
		1390	};
		1391	}
		1392	};
		1393	die if $@;
		1394	};
		1395
		1396	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1397	sub sig2name($) { &$_sig_name_init; &sig2name }
		1398
1071	sub signal {	1399	sub signal {
1072	my (undef, %arg) = @_;	1400	eval q{ # poor man's autoloading {}
		1401	# probe for availability of Async::Interrupt
		1402	if (_have_async_interrupt) {
		1403	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1073		1404
1074	unless ($SIGPIPE_R) {	1405	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1075	require Fcntl;	1406	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1076		1407
1077	if (AnyEvent::WIN32) {
1078	require AnyEvent::Util;
1079
1080	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1081	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1082	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1083	} else {	1408	} else {
		1409	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1410
		1411	require Fcntl;
		1412
		1413	if (AnyEvent::WIN32) {
		1414	require AnyEvent::Util;
		1415
		1416	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1417	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1418	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1419	} else {
1084	pipe $SIGPIPE_R, $SIGPIPE_W;	1420	pipe $SIGPIPE_R, $SIGPIPE_W;
1085	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1421	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1086	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1422	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1423
		1424	# not strictly required, as $^F is normally 2, but let's make sure...
		1425	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1426	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1427	}
		1428
		1429	$SIGPIPE_R
		1430	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1431
		1432	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1087	}	1433	}
1088		1434
1089	$SIGPIPE_R	1435	*signal = sub {
1090	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1436	my (undef, %arg) = @_;
1091		1437
1092	# not strictly required, as $^F is normally 2, but let's make sure...
1093	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1094	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1095
1096	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1097	}
1098
1099	my $signal = uc $arg{signal}	1438	my $signal = uc $arg{signal}
1100	or Carp::croak "required option 'signal' is missing";	1439	or Carp::croak "required option 'signal' is missing";
1101		1440
		1441	if ($HAVE_ASYNC_INTERRUPT) {
		1442	# async::interrupt
		1443
		1444	$signal = sig2num $signal;
1102	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1445	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1446
		1447	$SIG_ASY{$signal} ||= new Async::Interrupt
		1448	cb => sub { undef $SIG_EV{$signal} },
		1449	signal => $signal,
		1450	pipe => [$SIGPIPE_R->filenos],
		1451	pipe_autodrain => 0,
		1452	;
		1453
		1454	} else {
		1455	# pure perl
		1456
		1457	# AE::Util has been loaded in signal
		1458	$signal = sig2name $signal;
		1459	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1460
1103	$SIG{$signal} ||= sub {	1461	$SIG{$signal} ||= sub {
1104	local $!;	1462	local $!;
1105	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1463	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1106	undef $SIG_EV{$signal};	1464	undef $SIG_EV{$signal};
		1465	};
		1466
		1467	# can't do signal processing without introducing races in pure perl,
		1468	# so limit the signal latency.
		1469	_sig_add;
		1470	}
		1471
		1472	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1473	};
		1474
		1475	*AnyEvent::Base::signal::DESTROY = sub {
		1476	my ($signal, $cb) = @{$_[0]};
		1477
		1478	_sig_del;
		1479
		1480	delete $SIG_CB{$signal}{$cb};
		1481
		1482	$HAVE_ASYNC_INTERRUPT
		1483	? delete $SIG_ASY{$signal}
		1484	: # delete doesn't work with older perls - they then
		1485	# print weird messages, or just unconditionally exit
		1486	# instead of getting the default action.
		1487	undef $SIG{$signal}
		1488	unless keys %{ $SIG_CB{$signal} };
		1489	};
1107	};	1490	};
1108		1491	die if $@;
1109	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1492	&signal
1110	}
1111
1112	sub AnyEvent::Base::Signal::DESTROY {
1113	my ($signal, $cb) = @{$_[0]};
1114
1115	delete $SIG_CB{$signal}{$cb};
1116
1117	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1118	}	1493	}
1119		1494
1120	# default implementation for ->child	1495	# default implementation for ->child
1121		1496
1122	our %PID_CB;	1497	our %PID_CB;
1123	our $CHLD_W;	1498	our $CHLD_W;
1124	our $CHLD_DELAY_W;	1499	our $CHLD_DELAY_W;
1125	our $PID_IDLE;
1126	our $WNOHANG;	1500	our $WNOHANG;
1127		1501
1128	sub _child_wait {	1502	sub _emit_childstatus($$) {
1129	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1503	my (undef, $rpid, $rstatus) = @_;
		1504
		1505	$_->($rpid, $rstatus)
1130	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1506	for values %{ $PID_CB{$rpid} || {} },
1131	(values %{ $PID_CB{0} || {} });	1507	values %{ $PID_CB{0} || {} };
1132	}
1133
1134	undef $PID_IDLE;
1135	}	1508	}
1136		1509
1137	sub _sigchld {	1510	sub _sigchld {
1138	# make sure we deliver these changes "synchronous" with the event loop.	1511	my $pid;
1139	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {	1512
1140	undef $CHLD_DELAY_W;	1513	AnyEvent->_emit_childstatus ($pid, $?)
1141	&_child_wait;	1514	while ($pid = waitpid -1, $WNOHANG) > 0;
1142	});
1143	}	1515	}
1144		1516
1145	sub child {	1517	sub child {
1146	my (undef, %arg) = @_;	1518	my (undef, %arg) = @_;
1147		1519
1148	defined (my $pid = $arg{pid} + 0)	1520	defined (my $pid = $arg{pid} + 0)
1149	or Carp::croak "required option 'pid' is missing";	1521	or Carp::croak "required option 'pid' is missing";
1150		1522
1151	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1523	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1152		1524
1153	unless ($WNOHANG) {	1525	# WNOHANG is almost cetrainly 1 everywhere
		1526	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1527	? 1
1154	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1528	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1155	}
1156		1529
1157	unless ($CHLD_W) {	1530	unless ($CHLD_W) {
1158	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1531	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1159	# child could be a zombie already, so make at least one round	1532	# child could be a zombie already, so make at least one round
1160	&_sigchld;	1533	&_sigchld;
1161	}	1534	}
1162		1535
1163	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1536	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1164	}	1537	}
1165		1538
1166	sub AnyEvent::Base::Child::DESTROY {	1539	sub AnyEvent::Base::child::DESTROY {
1167	my ($pid, $cb) = @{$_[0]};	1540	my ($pid, $cb) = @{$_[0]};
1168		1541
1169	delete $PID_CB{$pid}{$cb};	1542	delete $PID_CB{$pid}{$cb};
1170	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1543	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1171		1544
1172	undef $CHLD_W unless keys %PID_CB;	1545	undef $CHLD_W unless keys %PID_CB;
1173	}	1546	}
1174		1547
		1548	# idle emulation is done by simply using a timer, regardless
		1549	# of whether the process is idle or not, and not letting
		1550	# the callback use more than 50% of the time.
		1551	sub idle {
		1552	my (undef, %arg) = @_;
		1553
		1554	my ($cb, $w, $rcb) = $arg{cb};
		1555
		1556	$rcb = sub {
		1557	if ($cb) {
		1558	$w = _time;
		1559	&$cb;
		1560	$w = _time - $w;
		1561
		1562	# never use more then 50% of the time for the idle watcher,
		1563	# within some limits
		1564	$w = 0.0001 if $w < 0.0001;
		1565	$w = 5 if $w > 5;
		1566
		1567	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1568	} else {
		1569	# clean up...
		1570	undef $w;
		1571	undef $rcb;
		1572	}
		1573	};
		1574
		1575	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1576
		1577	bless \\$cb, "AnyEvent::Base::idle"
		1578	}
		1579
		1580	sub AnyEvent::Base::idle::DESTROY {
		1581	undef $${$_[0]};
		1582	}
		1583
1175	package AnyEvent::CondVar;	1584	package AnyEvent::CondVar;
1176		1585
1177	our @ISA = AnyEvent::CondVar::Base::;	1586	our @ISA = AnyEvent::CondVar::Base::;
1178		1587
1179	package AnyEvent::CondVar::Base;	1588	package AnyEvent::CondVar::Base;
1180		1589
1181	use overload	1590	#use overload
1182	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1591	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1183	fallback => 1;	1592	# fallback => 1;
		1593
		1594	# save 300+ kilobytes by dirtily hardcoding overloading
		1595	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1596	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1597	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1598	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1599
		1600	our $WAITING;
1184		1601
1185	sub _send {	1602	sub _send {
1186	# nop	1603	# nop
1187	}	1604	}
1188		1605
…		…
1201	sub ready {	1618	sub ready {
1202	$_[0]{_ae_sent}	1619	$_[0]{_ae_sent}
1203	}	1620	}
1204		1621
1205	sub _wait {	1622	sub _wait {
		1623	$WAITING
		1624	and !$_[0]{_ae_sent}
		1625	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1626
		1627	local $WAITING = 1;
1206	AnyEvent->one_event while !$_[0]{_ae_sent};	1628	AnyEvent->one_event while !$_[0]{_ae_sent};
1207	}	1629	}
1208		1630
1209	sub recv {	1631	sub recv {
1210	$_[0]->_wait;	1632	$_[0]->_wait;
…		…
1212	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1634	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1213	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1635	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1214	}	1636	}
1215		1637
1216	sub cb {	1638	sub cb {
1217	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1639	my $cv = shift;
		1640
		1641	@_
		1642	and $cv->{_ae_cb} = shift
		1643	and $cv->{_ae_sent}
		1644	and (delete $cv->{_ae_cb})->($cv);
		1645
1218	$_[0]{_ae_cb}	1646	$cv->{_ae_cb}
1219	}	1647	}
1220		1648
1221	sub begin {	1649	sub begin {
1222	++$_[0]{_ae_counter};	1650	++$_[0]{_ae_counter};
1223	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1651	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1229	}	1657	}
1230		1658
1231	# undocumented/compatibility with pre-3.4	1659	# undocumented/compatibility with pre-3.4
1232	*broadcast = \&send;	1660	*broadcast = \&send;
1233	*wait = \&_wait;	1661	*wait = \&_wait;
		1662
		1663	#############################################################################
		1664	# "new" API, currently only emulation of it
		1665	#############################################################################
		1666
		1667	package AE;
		1668
		1669	sub io($$$) {
		1670	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1671	}
		1672
		1673	sub timer($$$) {
		1674	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2]);
		1675	}
		1676
		1677	sub signal($$) {
		1678	AnyEvent->signal (signal => $_[0], cb => $_[1]);
		1679	}
		1680
		1681	sub child($$) {
		1682	AnyEvent->child (pid => $_[0], cb => $_[1]);
		1683	}
		1684
		1685	sub idle($) {
		1686	AnyEvent->idle (cb => $_[0]);
		1687	}
		1688
		1689	sub cv(;&) {
		1690	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1691	}
		1692
		1693	sub now() {
		1694	AnyEvent->now
		1695	}
		1696
		1697	sub now_update() {
		1698	AnyEvent->now_update
		1699	}
		1700
		1701	sub time() {
		1702	AnyEvent->time
		1703	}
1234		1704
1235	=head1 ERROR AND EXCEPTION HANDLING	1705	=head1 ERROR AND EXCEPTION HANDLING
1236		1706
1237	In general, AnyEvent does not do any error handling - it relies on the	1707	In general, AnyEvent does not do any error handling - it relies on the
1238	caller to do that if required. The L<AnyEvent::Strict> module (see also	1708	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1251	so on.	1721	so on.
1252		1722
1253	=head1 ENVIRONMENT VARIABLES	1723	=head1 ENVIRONMENT VARIABLES
1254		1724
1255	The following environment variables are used by this module or its	1725	The following environment variables are used by this module or its
1256	submodules:	1726	submodules.
		1727
		1728	Note that AnyEvent will remove I<all> environment variables starting with
		1729	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1730	enabled.
1257		1731
1258	=over 4	1732	=over 4
1259		1733
1260	=item C<PERL_ANYEVENT_VERBOSE>	1734	=item C<PERL_ANYEVENT_VERBOSE>
1261		1735
…		…
1268	C<PERL_ANYEVENT_MODEL>.	1742	C<PERL_ANYEVENT_MODEL>.
1269		1743
1270	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1744	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1271	model it chooses.	1745	model it chooses.
1272		1746
		1747	When set to C<8> or higher, then AnyEvent will report extra information on
		1748	which optional modules it loads and how it implements certain features.
		1749
1273	=item C<PERL_ANYEVENT_STRICT>	1750	=item C<PERL_ANYEVENT_STRICT>
1274		1751
1275	AnyEvent does not do much argument checking by default, as thorough	1752	AnyEvent does not do much argument checking by default, as thorough
1276	argument checking is very costly. Setting this variable to a true value	1753	argument checking is very costly. Setting this variable to a true value
1277	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1754	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1278	check the arguments passed to most method calls. If it finds any problems	1755	check the arguments passed to most method calls. If it finds any problems,
1279	it will croak.	1756	it will croak.
1280		1757
1281	In other words, enables "strict" mode.	1758	In other words, enables "strict" mode.
1282		1759
1283	Unlike C<use strict>, it is definitely recommended ot keep it off in	1760	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1284	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1761	>>, it is definitely recommended to keep it off in production. Keeping
1285	developing programs can be very useful, however.	1762	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1763	can be very useful, however.
1286		1764
1287	=item C<PERL_ANYEVENT_MODEL>	1765	=item C<PERL_ANYEVENT_MODEL>
1288		1766
1289	This can be used to specify the event model to be used by AnyEvent, before	1767	This can be used to specify the event model to be used by AnyEvent, before
1290	auto detection and -probing kicks in. It must be a string consisting	1768	auto detection and -probing kicks in. It must be a string consisting
…		…
1333		1811
1334	=item C<PERL_ANYEVENT_MAX_FORKS>	1812	=item C<PERL_ANYEVENT_MAX_FORKS>
1335		1813
1336	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1814	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1337	will create in parallel.	1815	will create in parallel.
		1816
		1817	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1818
		1819	The default value for the C<max_outstanding> parameter for the default DNS
		1820	resolver - this is the maximum number of parallel DNS requests that are
		1821	sent to the DNS server.
		1822
		1823	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1824
		1825	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1826	configuration) in the default resolver. When set to the empty string, no
		1827	default config will be used.
		1828
		1829	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1830
		1831	When neither C<ca_file> nor C<ca_path> was specified during
		1832	L<AnyEvent::TLS> context creation, and either of these environment
		1833	variables exist, they will be used to specify CA certificate locations
		1834	instead of a system-dependent default.
		1835
		1836	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1837
		1838	When these are set to C<1>, then the respective modules are not
		1839	loaded. Mostly good for testing AnyEvent itself.
1338		1840
1339	=back	1841	=back
1340		1842
1341	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1843	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1342		1844
…		…
1587	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2089	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1588	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2090	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1589	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2091	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1590	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2092	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1591	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2093	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		2094	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		2095	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1592	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2096	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1593	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2097	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1594	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2098	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1595	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2099	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1596		2100
…		…
1625	performance becomes really bad with lots of file descriptors (and few of	2129	performance becomes really bad with lots of file descriptors (and few of
1626	them active), of course, but this was not subject of this benchmark.	2130	them active), of course, but this was not subject of this benchmark.
1627		2131
1628	The C<Event> module has a relatively high setup and callback invocation	2132	The C<Event> module has a relatively high setup and callback invocation
1629	cost, but overall scores in on the third place.	2133	cost, but overall scores in on the third place.
		2134
		2135	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2136	when using its pure perl backend.
1630		2137
1631	C<Glib>'s memory usage is quite a bit higher, but it features a	2138	C<Glib>'s memory usage is quite a bit higher, but it features a
1632	faster callback invocation and overall ends up in the same class as	2139	faster callback invocation and overall ends up in the same class as
1633	C<Event>. However, Glib scales extremely badly, doubling the number of	2140	C<Event>. However, Glib scales extremely badly, doubling the number of
1634	watchers increases the processing time by more than a factor of four,	2141	watchers increases the processing time by more than a factor of four,
…		…
1712	it to another server. This includes deleting the old timeout and creating	2219	it to another server. This includes deleting the old timeout and creating
1713	a new one that moves the timeout into the future.	2220	a new one that moves the timeout into the future.
1714		2221
1715	=head3 Results	2222	=head3 Results
1716		2223
1717	name sockets create request	2224	name sockets create request
1718	EV 20000 69.01 11.16	2225	EV 20000 69.01 11.16
1719	Perl 20000 73.32 35.87	2226	Perl 20000 73.32 35.87
		2227	IOAsync 20000 157.00 98.14 epoll
		2228	IOAsync 20000 159.31 616.06 poll
1720	Event 20000 212.62 257.32	2229	Event 20000 212.62 257.32
1721	Glib 20000 651.16 1896.30	2230	Glib 20000 651.16 1896.30
1722	POE 20000 349.67 12317.24 uses POE::Loop::Event	2231	POE 20000 349.67 12317.24 uses POE::Loop::Event
1723		2232
1724	=head3 Discussion	2233	=head3 Discussion
1725		2234
1726	This benchmark I<does> measure scalability and overall performance of the	2235	This benchmark I<does> measure scalability and overall performance of the
1727	particular event loop.	2236	particular event loop.
…		…
1729	EV is again fastest. Since it is using epoll on my system, the setup time	2238	EV is again fastest. Since it is using epoll on my system, the setup time
1730	is relatively high, though.	2239	is relatively high, though.
1731		2240
1732	Perl surprisingly comes second. It is much faster than the C-based event	2241	Perl surprisingly comes second. It is much faster than the C-based event
1733	loops Event and Glib.	2242	loops Event and Glib.
		2243
		2244	IO::Async performs very well when using its epoll backend, and still quite
		2245	good compared to Glib when using its pure perl backend.
1734		2246
1735	Event suffers from high setup time as well (look at its code and you will	2247	Event suffers from high setup time as well (look at its code and you will
1736	understand why). Callback invocation also has a high overhead compared to	2248	understand why). Callback invocation also has a high overhead compared to
1737	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2249	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1738	uses select or poll in basically all documented configurations.	2250	uses select or poll in basically all documented configurations.
…		…
1801	=item * C-based event loops perform very well with small number of	2313	=item * C-based event loops perform very well with small number of
1802	watchers, as the management overhead dominates.	2314	watchers, as the management overhead dominates.
1803		2315
1804	=back	2316	=back
1805		2317
		2318	=head2 THE IO::Lambda BENCHMARK
		2319
		2320	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2321	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2322	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2323	shouldn't come as a surprise to anybody). As such, the benchmark is
		2324	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2325	very optimal. But how would AnyEvent compare when used without the extra
		2326	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2327
		2328	The benchmark itself creates an echo-server, and then, for 500 times,
		2329	connects to the echo server, sends a line, waits for the reply, and then
		2330	creates the next connection. This is a rather bad benchmark, as it doesn't
		2331	test the efficiency of the framework or much non-blocking I/O, but it is a
		2332	benchmark nevertheless.
		2333
		2334	name runtime
		2335	Lambda/select 0.330 sec
		2336	+ optimized 0.122 sec
		2337	Lambda/AnyEvent 0.327 sec
		2338	+ optimized 0.138 sec
		2339	Raw sockets/select 0.077 sec
		2340	POE/select, components 0.662 sec
		2341	POE/select, raw sockets 0.226 sec
		2342	POE/select, optimized 0.404 sec
		2343
		2344	AnyEvent/select/nb 0.085 sec
		2345	AnyEvent/EV/nb 0.068 sec
		2346	+state machine 0.134 sec
		2347
		2348	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2349	benchmarks actually make blocking connects and use 100% blocking I/O,
		2350	defeating the purpose of an event-based solution. All of the newly
		2351	written AnyEvent benchmarks use 100% non-blocking connects (using
		2352	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2353	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2354	generally require a lot more bookkeeping and event handling than blocking
		2355	connects (which involve a single syscall only).
		2356
		2357	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2358	offers similar expressive power as POE and IO::Lambda, using conventional
		2359	Perl syntax. This means that both the echo server and the client are 100%
		2360	non-blocking, further placing it at a disadvantage.
		2361
		2362	As you can see, the AnyEvent + EV combination even beats the
		2363	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2364	backend easily beats IO::Lambda and POE.
		2365
		2366	And even the 100% non-blocking version written using the high-level (and
		2367	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2368	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2369	in a non-blocking way.
		2370
		2371	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2372	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2373	part of the IO::lambda distribution and were used without any changes.
		2374
1806		2375
1807	=head1 SIGNALS	2376	=head1 SIGNALS
1808		2377
1809	AnyEvent currently installs handlers for these signals:	2378	AnyEvent currently installs handlers for these signals:
1810		2379
…		…
1813	=item SIGCHLD	2382	=item SIGCHLD
1814		2383
1815	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2384	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1816	emulation for event loops that do not support them natively. Also, some	2385	emulation for event loops that do not support them natively. Also, some
1817	event loops install a similar handler.	2386	event loops install a similar handler.
		2387
		2388	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2389	AnyEvent will reset it to default, to avoid losing child exit statuses.
1818		2390
1819	=item SIGPIPE	2391	=item SIGPIPE
1820		2392
1821	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2393	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1822	when AnyEvent gets loaded.	2394	when AnyEvent gets loaded.
…		…
1834		2406
1835	=back	2407	=back
1836		2408
1837	=cut	2409	=cut
1838		2410
		2411	undef $SIG{CHLD}
		2412	if $SIG{CHLD} eq 'IGNORE';
		2413
1839	$SIG{PIPE} = sub { }	2414	$SIG{PIPE} = sub { }
1840	unless defined $SIG{PIPE};	2415	unless defined $SIG{PIPE};
		2416
		2417	=head1 RECOMMENDED/OPTIONAL MODULES
		2418
		2419	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2420	it's built-in modules) are required to use it.
		2421
		2422	That does not mean that AnyEvent won't take advantage of some additional
		2423	modules if they are installed.
		2424
		2425	This section epxlains which additional modules will be used, and how they
		2426	affect AnyEvent's operetion.
		2427
		2428	=over 4
		2429
		2430	=item L<Async::Interrupt>
		2431
		2432	This slightly arcane module is used to implement fast signal handling: To
		2433	my knowledge, there is no way to do completely race-free and quick
		2434	signal handling in pure perl. To ensure that signals still get
		2435	delivered, AnyEvent will start an interval timer to wake up perl (and
		2436	catch the signals) with some delay (default is 10 seconds, look for
		2437	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2438
		2439	If this module is available, then it will be used to implement signal
		2440	catching, which means that signals will not be delayed, and the event loop
		2441	will not be interrupted regularly, which is more efficient (And good for
		2442	battery life on laptops).
		2443
		2444	This affects not just the pure-perl event loop, but also other event loops
		2445	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2446
		2447	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2448	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2449	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2450	does nothing for those backends.
		2451
		2452	=item L<EV>
		2453
		2454	This module isn't really "optional", as it is simply one of the backend
		2455	event loops that AnyEvent can use. However, it is simply the best event
		2456	loop available in terms of features, speed and stability: It supports
		2457	the AnyEvent API optimally, implements all the watcher types in XS, does
		2458	automatic timer adjustments even when no monotonic clock is available,
		2459	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2460	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2461	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2462
		2463	=item L<Guard>
		2464
		2465	The guard module, when used, will be used to implement
		2466	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2467	lot less memory), but otherwise doesn't affect guard operation much. It is
		2468	purely used for performance.
		2469
		2470	=item L<JSON> and L<JSON::XS>
		2471
		2472	This module is required when you want to read or write JSON data via
		2473	L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2474	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2475
		2476	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2477	installed.
		2478
		2479	=item L<Net::SSLeay>
		2480
		2481	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2482	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2483	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2484
		2485	=item L<Time::HiRes>
		2486
		2487	This module is part of perl since release 5.008. It will be used when the
		2488	chosen event library does not come with a timing source on it's own. The
		2489	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2490	try to use a monotonic clock for timing stability.
		2491
		2492	=back
1841		2493
1842		2494
1843	=head1 FORK	2495	=head1 FORK
1844		2496
1845	Most event libraries are not fork-safe. The ones who are usually are	2497	Most event libraries are not fork-safe. The ones who are usually are
1846	because they rely on inefficient but fork-safe C<select> or C<poll>	2498	because they rely on inefficient but fork-safe C<select> or C<poll>
1847	calls. Only L<EV> is fully fork-aware.	2499	calls. Only L<EV> is fully fork-aware.
1848		2500
1849	If you have to fork, you must either do so I<before> creating your first	2501	If you have to fork, you must either do so I<before> creating your first
1850	watcher OR you must not use AnyEvent at all in the child.	2502	watcher OR you must not use AnyEvent at all in the child OR you must do
		2503	something completely out of the scope of AnyEvent.
1851		2504
1852		2505
1853	=head1 SECURITY CONSIDERATIONS	2506	=head1 SECURITY CONSIDERATIONS
1854		2507
1855	AnyEvent can be forced to load any event model via	2508	AnyEvent can be forced to load any event model via
…		…
1867	use AnyEvent;	2520	use AnyEvent;
1868		2521
1869	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2522	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1870	be used to probe what backend is used and gain other information (which is	2523	be used to probe what backend is used and gain other information (which is
1871	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2524	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1872	$ENV{PERL_ANYEGENT_STRICT}.	2525	$ENV{PERL_ANYEVENT_STRICT}.
		2526
		2527	Note that AnyEvent will remove I<all> environment variables starting with
		2528	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2529	enabled.
1873		2530
1874		2531
1875	=head1 BUGS	2532	=head1 BUGS
1876		2533
1877	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2534	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
…		…
1889	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2546	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1890		2547
1891	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2548	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1892	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2549	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1893	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2550	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1894	L<AnyEvent::Impl::POE>.	2551	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1895		2552
1896	Non-blocking file handles, sockets, TCP clients and	2553	Non-blocking file handles, sockets, TCP clients and
1897	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2554	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1898		2555
1899	Asynchronous DNS: L<AnyEvent::DNS>.	2556	Asynchronous DNS: L<AnyEvent::DNS>.
1900		2557
1901	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2558	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2559	L<Coro::Event>,
1902		2560
1903	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2561	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2562	L<AnyEvent::HTTP>.
1904		2563
1905		2564
1906	=head1 AUTHOR	2565	=head1 AUTHOR
1907		2566
1908	Marc Lehmann <schmorp@schmorp.de>	2567	Marc Lehmann <schmorp@schmorp.de>

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