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Revision 1.200 by root, Wed Apr 1 14:02:27 2009 UTC vs.
Revision 1.268 by root, Thu Jul 30 16:39:19 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
…		…
649	variable itself. Calling C<recv> inside the callback or at any later time	797	variable itself. Calling C<recv> inside the callback or at any later time
650	is guaranteed not to block.	798	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 = 4.9;
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	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1093	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1094
1095	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1096	}
1097
1098	my $signal = uc $arg{signal}	1438	my $signal = uc $arg{signal}
1099	or Carp::croak "required option 'signal' is missing";	1439	or Carp::croak "required option 'signal' is missing";
1100		1440
		1441	if ($HAVE_ASYNC_INTERRUPT) {
		1442	# async::interrupt
		1443
		1444	$signal = sig2num $signal;
1101	$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
1102	$SIG{$signal} ||= sub {	1461	$SIG{$signal} ||= sub {
		1462	local $!;
1103	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1463	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1104	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	};
1105	};	1490	};
1106		1491	die if $@;
1107	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1492	&signal
1108	}
1109
1110	sub AnyEvent::Base::Signal::DESTROY {
1111	my ($signal, $cb) = @{$_[0]};
1112
1113	delete $SIG_CB{$signal}{$cb};
1114
1115	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1116	}	1493	}
1117		1494
1118	# default implementation for ->child	1495	# default implementation for ->child
1119		1496
1120	our %PID_CB;	1497	our %PID_CB;
1121	our $CHLD_W;	1498	our $CHLD_W;
1122	our $CHLD_DELAY_W;	1499	our $CHLD_DELAY_W;
1123	our $PID_IDLE;
1124	our $WNOHANG;	1500	our $WNOHANG;
1125		1501
1126	sub _child_wait {	1502	sub _emit_childstatus($$) {
1127	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1503	my (undef, $rpid, $rstatus) = @_;
		1504
		1505	$_->($rpid, $rstatus)
1128	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1506	for values %{ $PID_CB{$rpid} || {} },
1129	(values %{ $PID_CB{0} || {} });	1507	values %{ $PID_CB{0} || {} };
1130	}
1131
1132	undef $PID_IDLE;
1133	}	1508	}
1134		1509
1135	sub _sigchld {	1510	sub _sigchld {
1136	# make sure we deliver these changes "synchronous" with the event loop.	1511	my $pid;
1137	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {	1512
1138	undef $CHLD_DELAY_W;	1513	AnyEvent->_emit_childstatus ($pid, $?)
1139	&_child_wait;	1514	while ($pid = waitpid -1, $WNOHANG) > 0;
1140	});
1141	}	1515	}
1142		1516
1143	sub child {	1517	sub child {
1144	my (undef, %arg) = @_;	1518	my (undef, %arg) = @_;
1145		1519
1146	defined (my $pid = $arg{pid} + 0)	1520	defined (my $pid = $arg{pid} + 0)
1147	or Carp::croak "required option 'pid' is missing";	1521	or Carp::croak "required option 'pid' is missing";
1148		1522
1149	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1523	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1150		1524
1151	unless ($WNOHANG) {	1525	# WNOHANG is almost cetrainly 1 everywhere
		1526	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1527	? 1
1152	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1528	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1153	}
1154		1529
1155	unless ($CHLD_W) {	1530	unless ($CHLD_W) {
1156	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1531	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1157	# child could be a zombie already, so make at least one round	1532	# child could be a zombie already, so make at least one round
1158	&_sigchld;	1533	&_sigchld;
1159	}	1534	}
1160		1535
1161	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1536	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1162	}	1537	}
1163		1538
1164	sub AnyEvent::Base::Child::DESTROY {	1539	sub AnyEvent::Base::child::DESTROY {
1165	my ($pid, $cb) = @{$_[0]};	1540	my ($pid, $cb) = @{$_[0]};
1166		1541
1167	delete $PID_CB{$pid}{$cb};	1542	delete $PID_CB{$pid}{$cb};
1168	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1543	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1169		1544
1170	undef $CHLD_W unless keys %PID_CB;	1545	undef $CHLD_W unless keys %PID_CB;
1171	}	1546	}
1172		1547
		1548	# idle emulation is done by simply using a timer, regardless
		1549	# of whether the process is idle or not, and not letting
		1550	# the callback use more than 50% of the time.
		1551	sub idle {
		1552	my (undef, %arg) = @_;
		1553
		1554	my ($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
1173	package AnyEvent::CondVar;	1584	package AnyEvent::CondVar;
1174		1585
1175	our @ISA = AnyEvent::CondVar::Base::;	1586	our @ISA = AnyEvent::CondVar::Base::;
1176		1587
1177	package AnyEvent::CondVar::Base;	1588	package AnyEvent::CondVar::Base;
1178		1589
1179	use overload	1590	#use overload
1180	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1591	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1181	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;
1182		1601
1183	sub _send {	1602	sub _send {
1184	# nop	1603	# nop
1185	}	1604	}
1186		1605
…		…
1199	sub ready {	1618	sub ready {
1200	$_[0]{_ae_sent}	1619	$_[0]{_ae_sent}
1201	}	1620	}
1202		1621
1203	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;
1204	AnyEvent->one_event while !$_[0]{_ae_sent};	1628	AnyEvent->one_event while !$_[0]{_ae_sent};
1205	}	1629	}
1206		1630
1207	sub recv {	1631	sub recv {
1208	$_[0]->_wait;	1632	$_[0]->_wait;
…		…
1227	}	1651	}
1228		1652
1229	# undocumented/compatibility with pre-3.4	1653	# undocumented/compatibility with pre-3.4
1230	*broadcast = \&send;	1654	*broadcast = \&send;
1231	*wait = \&_wait;	1655	*wait = \&_wait;
		1656
		1657	#############################################################################
		1658	# "new" API, currently only emulation of it
		1659	#############################################################################
		1660
		1661	package AE;
		1662
		1663	sub io($$$) {
		1664	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1665	}
		1666
		1667	sub timer($$$) {
		1668	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2]);
		1669	}
		1670
		1671	sub signal($$) {
		1672	AnyEvent->signal (signal => $_[0], cb => $_[1]);
		1673	}
		1674
		1675	sub child($$) {
		1676	AnyEvent->child (pid => $_[0], cb => $_[1]);
		1677	}
		1678
		1679	sub idle($) {
		1680	AnyEvent->idle (cb => $_[0]);
		1681	}
		1682
		1683	sub cv() {
		1684	AnyEvent->condvar
		1685	}
		1686
		1687	sub now() {
		1688	AnyEvent->now
		1689	}
		1690
		1691	sub now_update() {
		1692	AnyEvent->now_update
		1693	}
		1694
		1695	sub time() {
		1696	AnyEvent->time
		1697	}
1232		1698
1233	=head1 ERROR AND EXCEPTION HANDLING	1699	=head1 ERROR AND EXCEPTION HANDLING
1234		1700
1235	In general, AnyEvent does not do any error handling - it relies on the	1701	In general, AnyEvent does not do any error handling - it relies on the
1236	caller to do that if required. The L<AnyEvent::Strict> module (see also	1702	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1249	so on.	1715	so on.
1250		1716
1251	=head1 ENVIRONMENT VARIABLES	1717	=head1 ENVIRONMENT VARIABLES
1252		1718
1253	The following environment variables are used by this module or its	1719	The following environment variables are used by this module or its
1254	submodules:	1720	submodules.
		1721
		1722	Note that AnyEvent will remove I<all> environment variables starting with
		1723	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1724	enabled.
1255		1725
1256	=over 4	1726	=over 4
1257		1727
1258	=item C<PERL_ANYEVENT_VERBOSE>	1728	=item C<PERL_ANYEVENT_VERBOSE>
1259		1729
…		…
1266	C<PERL_ANYEVENT_MODEL>.	1736	C<PERL_ANYEVENT_MODEL>.
1267		1737
1268	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1738	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1269	model it chooses.	1739	model it chooses.
1270		1740
		1741	When set to C<8> or higher, then AnyEvent will report extra information on
		1742	which optional modules it loads and how it implements certain features.
		1743
1271	=item C<PERL_ANYEVENT_STRICT>	1744	=item C<PERL_ANYEVENT_STRICT>
1272		1745
1273	AnyEvent does not do much argument checking by default, as thorough	1746	AnyEvent does not do much argument checking by default, as thorough
1274	argument checking is very costly. Setting this variable to a true value	1747	argument checking is very costly. Setting this variable to a true value
1275	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1748	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1276	check the arguments passed to most method calls. If it finds any problems	1749	check the arguments passed to most method calls. If it finds any problems,
1277	it will croak.	1750	it will croak.
1278		1751
1279	In other words, enables "strict" mode.	1752	In other words, enables "strict" mode.
1280		1753
1281	Unlike C<use strict>, it is definitely recommended ot keep it off in	1754	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1282	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1755	>>, it is definitely recommended to keep it off in production. Keeping
1283	developing programs can be very useful, however.	1756	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1757	can be very useful, however.
1284		1758
1285	=item C<PERL_ANYEVENT_MODEL>	1759	=item C<PERL_ANYEVENT_MODEL>
1286		1760
1287	This can be used to specify the event model to be used by AnyEvent, before	1761	This can be used to specify the event model to be used by AnyEvent, before
1288	auto detection and -probing kicks in. It must be a string consisting	1762	auto detection and -probing kicks in. It must be a string consisting
…		…
1331		1805
1332	=item C<PERL_ANYEVENT_MAX_FORKS>	1806	=item C<PERL_ANYEVENT_MAX_FORKS>
1333		1807
1334	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1808	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1335	will create in parallel.	1809	will create in parallel.
		1810
		1811	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1812
		1813	The default value for the C<max_outstanding> parameter for the default DNS
		1814	resolver - this is the maximum number of parallel DNS requests that are
		1815	sent to the DNS server.
		1816
		1817	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1818
		1819	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1820	configuration) in the default resolver. When set to the empty string, no
		1821	default config will be used.
		1822
		1823	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1824
		1825	When neither C<ca_file> nor C<ca_path> was specified during
		1826	L<AnyEvent::TLS> context creation, and either of these environment
		1827	variables exist, they will be used to specify CA certificate locations
		1828	instead of a system-dependent default.
		1829
		1830	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1831
		1832	When these are set to C<1>, then the respective modules are not
		1833	loaded. Mostly good for testing AnyEvent itself.
1336		1834
1337	=back	1835	=back
1338		1836
1339	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1837	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1340		1838
…		…
1585	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2083	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1586	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2084	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1587	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2085	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1588	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2086	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1589	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2087	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		2088	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		2089	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1590	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2090	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1591	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2091	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1592	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2092	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1593	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2093	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1594		2094
…		…
1623	performance becomes really bad with lots of file descriptors (and few of	2123	performance becomes really bad with lots of file descriptors (and few of
1624	them active), of course, but this was not subject of this benchmark.	2124	them active), of course, but this was not subject of this benchmark.
1625		2125
1626	The C<Event> module has a relatively high setup and callback invocation	2126	The C<Event> module has a relatively high setup and callback invocation
1627	cost, but overall scores in on the third place.	2127	cost, but overall scores in on the third place.
		2128
		2129	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2130	when using its pure perl backend.
1628		2131
1629	C<Glib>'s memory usage is quite a bit higher, but it features a	2132	C<Glib>'s memory usage is quite a bit higher, but it features a
1630	faster callback invocation and overall ends up in the same class as	2133	faster callback invocation and overall ends up in the same class as
1631	C<Event>. However, Glib scales extremely badly, doubling the number of	2134	C<Event>. However, Glib scales extremely badly, doubling the number of
1632	watchers increases the processing time by more than a factor of four,	2135	watchers increases the processing time by more than a factor of four,
…		…
1710	it to another server. This includes deleting the old timeout and creating	2213	it to another server. This includes deleting the old timeout and creating
1711	a new one that moves the timeout into the future.	2214	a new one that moves the timeout into the future.
1712		2215
1713	=head3 Results	2216	=head3 Results
1714		2217
1715	name sockets create request	2218	name sockets create request
1716	EV 20000 69.01 11.16	2219	EV 20000 69.01 11.16
1717	Perl 20000 73.32 35.87	2220	Perl 20000 73.32 35.87
		2221	IOAsync 20000 157.00 98.14 epoll
		2222	IOAsync 20000 159.31 616.06 poll
1718	Event 20000 212.62 257.32	2223	Event 20000 212.62 257.32
1719	Glib 20000 651.16 1896.30	2224	Glib 20000 651.16 1896.30
1720	POE 20000 349.67 12317.24 uses POE::Loop::Event	2225	POE 20000 349.67 12317.24 uses POE::Loop::Event
1721		2226
1722	=head3 Discussion	2227	=head3 Discussion
1723		2228
1724	This benchmark I<does> measure scalability and overall performance of the	2229	This benchmark I<does> measure scalability and overall performance of the
1725	particular event loop.	2230	particular event loop.
…		…
1727	EV is again fastest. Since it is using epoll on my system, the setup time	2232	EV is again fastest. Since it is using epoll on my system, the setup time
1728	is relatively high, though.	2233	is relatively high, though.
1729		2234
1730	Perl surprisingly comes second. It is much faster than the C-based event	2235	Perl surprisingly comes second. It is much faster than the C-based event
1731	loops Event and Glib.	2236	loops Event and Glib.
		2237
		2238	IO::Async performs very well when using its epoll backend, and still quite
		2239	good compared to Glib when using its pure perl backend.
1732		2240
1733	Event suffers from high setup time as well (look at its code and you will	2241	Event suffers from high setup time as well (look at its code and you will
1734	understand why). Callback invocation also has a high overhead compared to	2242	understand why). Callback invocation also has a high overhead compared to
1735	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2243	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1736	uses select or poll in basically all documented configurations.	2244	uses select or poll in basically all documented configurations.
…		…
1799	=item * C-based event loops perform very well with small number of	2307	=item * C-based event loops perform very well with small number of
1800	watchers, as the management overhead dominates.	2308	watchers, as the management overhead dominates.
1801		2309
1802	=back	2310	=back
1803		2311
		2312	=head2 THE IO::Lambda BENCHMARK
		2313
		2314	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2315	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2316	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2317	shouldn't come as a surprise to anybody). As such, the benchmark is
		2318	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2319	very optimal. But how would AnyEvent compare when used without the extra
		2320	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2321
		2322	The benchmark itself creates an echo-server, and then, for 500 times,
		2323	connects to the echo server, sends a line, waits for the reply, and then
		2324	creates the next connection. This is a rather bad benchmark, as it doesn't
		2325	test the efficiency of the framework or much non-blocking I/O, but it is a
		2326	benchmark nevertheless.
		2327
		2328	name runtime
		2329	Lambda/select 0.330 sec
		2330	+ optimized 0.122 sec
		2331	Lambda/AnyEvent 0.327 sec
		2332	+ optimized 0.138 sec
		2333	Raw sockets/select 0.077 sec
		2334	POE/select, components 0.662 sec
		2335	POE/select, raw sockets 0.226 sec
		2336	POE/select, optimized 0.404 sec
		2337
		2338	AnyEvent/select/nb 0.085 sec
		2339	AnyEvent/EV/nb 0.068 sec
		2340	+state machine 0.134 sec
		2341
		2342	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2343	benchmarks actually make blocking connects and use 100% blocking I/O,
		2344	defeating the purpose of an event-based solution. All of the newly
		2345	written AnyEvent benchmarks use 100% non-blocking connects (using
		2346	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2347	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2348	generally require a lot more bookkeeping and event handling than blocking
		2349	connects (which involve a single syscall only).
		2350
		2351	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2352	offers similar expressive power as POE and IO::Lambda, using conventional
		2353	Perl syntax. This means that both the echo server and the client are 100%
		2354	non-blocking, further placing it at a disadvantage.
		2355
		2356	As you can see, the AnyEvent + EV combination even beats the
		2357	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2358	backend easily beats IO::Lambda and POE.
		2359
		2360	And even the 100% non-blocking version written using the high-level (and
		2361	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2362	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2363	in a non-blocking way.
		2364
		2365	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2366	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2367	part of the IO::lambda distribution and were used without any changes.
		2368
1804		2369
1805	=head1 SIGNALS	2370	=head1 SIGNALS
1806		2371
1807	AnyEvent currently installs handlers for these signals:	2372	AnyEvent currently installs handlers for these signals:
1808		2373
…		…
1811	=item SIGCHLD	2376	=item SIGCHLD
1812		2377
1813	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2378	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1814	emulation for event loops that do not support them natively. Also, some	2379	emulation for event loops that do not support them natively. Also, some
1815	event loops install a similar handler.	2380	event loops install a similar handler.
		2381
		2382	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2383	AnyEvent will reset it to default, to avoid losing child exit statuses.
1816		2384
1817	=item SIGPIPE	2385	=item SIGPIPE
1818		2386
1819	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2387	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1820	when AnyEvent gets loaded.	2388	when AnyEvent gets loaded.
…		…
1832		2400
1833	=back	2401	=back
1834		2402
1835	=cut	2403	=cut
1836		2404
		2405	undef $SIG{CHLD}
		2406	if $SIG{CHLD} eq 'IGNORE';
		2407
1837	$SIG{PIPE} = sub { }	2408	$SIG{PIPE} = sub { }
1838	unless defined $SIG{PIPE};	2409	unless defined $SIG{PIPE};
		2410
		2411	=head1 RECOMMENDED/OPTIONAL MODULES
		2412
		2413	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2414	it's built-in modules) are required to use it.
		2415
		2416	That does not mean that AnyEvent won't take advantage of some additional
		2417	modules if they are installed.
		2418
		2419	This section epxlains which additional modules will be used, and how they
		2420	affect AnyEvent's operetion.
		2421
		2422	=over 4
		2423
		2424	=item L<Async::Interrupt>
		2425
		2426	This slightly arcane module is used to implement fast signal handling: To
		2427	my knowledge, there is no way to do completely race-free and quick
		2428	signal handling in pure perl. To ensure that signals still get
		2429	delivered, AnyEvent will start an interval timer to wake up perl (and
		2430	catch the signals) with some delay (default is 10 seconds, look for
		2431	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2432
		2433	If this module is available, then it will be used to implement signal
		2434	catching, which means that signals will not be delayed, and the event loop
		2435	will not be interrupted regularly, which is more efficient (And good for
		2436	battery life on laptops).
		2437
		2438	This affects not just the pure-perl event loop, but also other event loops
		2439	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2440
		2441	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2442	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2443	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2444	does nothing for those backends.
		2445
		2446	=item L<EV>
		2447
		2448	This module isn't really "optional", as it is simply one of the backend
		2449	event loops that AnyEvent can use. However, it is simply the best event
		2450	loop available in terms of features, speed and stability: It supports
		2451	the AnyEvent API optimally, implements all the watcher types in XS, does
		2452	automatic timer adjustments even when no monotonic clock is available,
		2453	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2454	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2455	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2456
		2457	=item L<Guard>
		2458
		2459	The guard module, when used, will be used to implement
		2460	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2461	lot less memory), but otherwise doesn't affect guard operation much. It is
		2462	purely used for performance.
		2463
		2464	=item L<JSON> and L<JSON::XS>
		2465
		2466	This module is required when you want to read or write JSON data via
		2467	L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2468	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2469
		2470	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2471	installed.
		2472
		2473	=item L<Net::SSLeay>
		2474
		2475	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2476	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2477	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2478
		2479	=item L<Time::HiRes>
		2480
		2481	This module is part of perl since release 5.008. It will be used when the
		2482	chosen event library does not come with a timing source on it's own. The
		2483	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2484	try to use a monotonic clock for timing stability.
		2485
		2486	=back
1839		2487
1840		2488
1841	=head1 FORK	2489	=head1 FORK
1842		2490
1843	Most event libraries are not fork-safe. The ones who are usually are	2491	Most event libraries are not fork-safe. The ones who are usually are
1844	because they rely on inefficient but fork-safe C<select> or C<poll>	2492	because they rely on inefficient but fork-safe C<select> or C<poll>
1845	calls. Only L<EV> is fully fork-aware.	2493	calls. Only L<EV> is fully fork-aware.
1846		2494
1847	If you have to fork, you must either do so I<before> creating your first	2495	If you have to fork, you must either do so I<before> creating your first
1848	watcher OR you must not use AnyEvent at all in the child.	2496	watcher OR you must not use AnyEvent at all in the child OR you must do
		2497	something completely out of the scope of AnyEvent.
1849		2498
1850		2499
1851	=head1 SECURITY CONSIDERATIONS	2500	=head1 SECURITY CONSIDERATIONS
1852		2501
1853	AnyEvent can be forced to load any event model via	2502	AnyEvent can be forced to load any event model via
…		…
1865	use AnyEvent;	2514	use AnyEvent;
1866		2515
1867	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2516	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1868	be used to probe what backend is used and gain other information (which is	2517	be used to probe what backend is used and gain other information (which is
1869	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2518	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1870	$ENV{PERL_ANYEGENT_STRICT}.	2519	$ENV{PERL_ANYEVENT_STRICT}.
		2520
		2521	Note that AnyEvent will remove I<all> environment variables starting with
		2522	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2523	enabled.
1871		2524
1872		2525
1873	=head1 BUGS	2526	=head1 BUGS
1874		2527
1875	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2528	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
…		…
1887	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2540	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1888		2541
1889	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2542	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1890	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2543	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1891	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2544	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1892	L<AnyEvent::Impl::POE>.	2545	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1893		2546
1894	Non-blocking file handles, sockets, TCP clients and	2547	Non-blocking file handles, sockets, TCP clients and
1895	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2548	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1896		2549
1897	Asynchronous DNS: L<AnyEvent::DNS>.	2550	Asynchronous DNS: L<AnyEvent::DNS>.
1898		2551
1899	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2552	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2553	L<Coro::Event>,
1900		2554
1901	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2555	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2556	L<AnyEvent::HTTP>.
1902		2557
1903		2558
1904	=head1 AUTHOR	2559	=head1 AUTHOR
1905		2560
1906	Marc Lehmann <schmorp@schmorp.de>	2561	Marc Lehmann <schmorp@schmorp.de>

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