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Revision 1.180 by root, Sat Sep 6 07:00:45 2008 UTC vs.
Revision 1.262 by root, Tue Jul 28 13:08:17 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 $condvar gets ->send
29	# use a condvar in callback mode:	37	# use a condvar in callback mode:
…		…
32	=head1 INTRODUCTION/TUTORIAL	40	=head1 INTRODUCTION/TUTORIAL
33		41
34	This manpage is mainly a reference manual. If you are interested	42	This manpage is mainly a reference manual. If you are interested
35	in a tutorial or some gentle introduction, have a look at the	43	in a tutorial or some gentle introduction, have a look at the
36	L<AnyEvent::Intro> manpage.	44	L<AnyEvent::Intro> manpage.
		45
		46	=head1 SUPPORT
		47
		48	There is a mailinglist for discussing all things AnyEvent, and an IRC
		49	channel, too.
		50
		51	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		52	Repository>, at L<http://anyevent.schmorp.de>, for more info.
37		53
38	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	54	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
39		55
40	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	56	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
41	nowadays. So what is different about AnyEvent?	57	nowadays. So what is different about AnyEvent?
…		…
137	These watchers are normal Perl objects with normal Perl lifetime. After	153	These watchers are normal Perl objects with normal Perl lifetime. After
138	creating a watcher it will immediately "watch" for events and invoke the	154	creating a watcher it will immediately "watch" for events and invoke the
139	callback when the event occurs (of course, only when the event model	155	callback when the event occurs (of course, only when the event model
140	is in control).	156	is in control).
141		157
		158	Note that B<callbacks must not permanently change global variables>
		159	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
		160	callbacks must not C<die> >>. The former is good programming practise in
		161	Perl and the latter stems from the fact that exception handling differs
		162	widely between event loops.
		163
142	To disable the watcher you have to destroy it (e.g. by setting the	164	To disable the watcher you have to destroy it (e.g. by setting the
143	variable you store it in to C<undef> or otherwise deleting all references	165	variable you store it in to C<undef> or otherwise deleting all references
144	to it).	166	to it).
145		167
146	All watchers are created by calling a method on the C<AnyEvent> class.	168	All watchers are created by calling a method on the C<AnyEvent> class.
…		…
162	=head2 I/O WATCHERS	184	=head2 I/O WATCHERS
163		185
164	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	186	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
165	with the following mandatory key-value pairs as arguments:	187	with the following mandatory key-value pairs as arguments:
166		188
167	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events	189	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
168	(AnyEvent might or might not keep a reference to this file handle). C<poll>	190	for events (AnyEvent might or might not keep a reference to this file
		191	handle). Note that only file handles pointing to things for which
		192	non-blocking operation makes sense are allowed. This includes sockets,
		193	most character devices, pipes, fifos and so on, but not for example files
		194	or block devices.
		195
169	must be a string that is either C<r> or C<w>, which creates a watcher	196	C<poll> must be a string that is either C<r> or C<w>, which creates a
170	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the	197	watcher waiting for "r"eadable or "w"ritable events, respectively.
		198
171	callback to invoke each time the file handle becomes ready.	199	C<cb> is the callback to invoke each time the file handle becomes ready.
172		200
173	Although the callback might get passed parameters, their value and	201	Although the callback might get passed parameters, their value and
174	presence is undefined and you cannot rely on them. Portable AnyEvent	202	presence is undefined and you cannot rely on them. Portable AnyEvent
175	callbacks cannot use arguments passed to I/O watcher callbacks.	203	callbacks cannot use arguments passed to I/O watcher callbacks.
176		204
…		…
308	In either case, if you care (and in most cases, you don't), then you	336	In either case, if you care (and in most cases, you don't), then you
309	can get whatever behaviour you want with any event loop, by taking the	337	can get whatever behaviour you want with any event loop, by taking the
310	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	338	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
311	account.	339	account.
312		340
		341	=item AnyEvent->now_update
		342
		343	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		344	the current time for each loop iteration (see the discussion of L<<
		345	AnyEvent->now >>, above).
		346
		347	When a callback runs for a long time (or when the process sleeps), then
		348	this "current" time will differ substantially from the real time, which
		349	might affect timers and time-outs.
		350
		351	When this is the case, you can call this method, which will update the
		352	event loop's idea of "current time".
		353
		354	Note that updating the time I<might> cause some events to be handled.
		355
313	=back	356	=back
314		357
315	=head2 SIGNAL WATCHERS	358	=head2 SIGNAL WATCHERS
316		359
317	You can watch for signals using a signal watcher, C<signal> is the signal	360	You can watch for signals using a signal watcher, C<signal> is the signal
…		…
326	invocation, and callback invocation will be synchronous. Synchronous means	369	invocation, and callback invocation will be synchronous. Synchronous means
327	that it might take a while until the signal gets handled by the process,	370	that it might take a while until the signal gets handled by the process,
328	but it is guaranteed not to interrupt any other callbacks.	371	but it is guaranteed not to interrupt any other callbacks.
329		372
330	The main advantage of using these watchers is that you can share a signal	373	The main advantage of using these watchers is that you can share a signal
331	between multiple watchers.	374	between multiple watchers, and AnyEvent will ensure that signals will not
		375	interrupt your program at bad times.
332		376
333	This watcher might use C<%SIG>, so programs overwriting those signals	377	This watcher might use C<%SIG> (depending on the event loop used),
334	directly will likely not work correctly.	378	so programs overwriting those signals directly will likely not work
		379	correctly.
335		380
336	Example: exit on SIGINT	381	Example: exit on SIGINT
337		382
338	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	383	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
339		384
		385	=head3 Signal Races, Delays and Workarounds
		386
		387	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		388	callbacks to signals in a generic way, which is a pity, as you cannot do
		389	race-free signal handling in perl. AnyEvent will try to do it's best, but
		390	in some cases, signals will be delayed. The maximum time a signal might
		391	be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10
		392	seconds). This variable can be changed only before the first signal
		393	watcher is created, and should be left alone otherwise. Higher values
		394	will cause fewer spurious wake-ups, which is better for power and CPU
		395	saving. All these problems can be avoided by installing the optional
		396	L<Async::Interrupt> module. This will not work with inherently broken
		397	event loops such as L<Event> or L<Event::Lib> (and not with L<POE>
		398	currently, as POE does it's own workaround with one-second latency). With
		399	those, you just have to suffer the delays.
		400
340	=head2 CHILD PROCESS WATCHERS	401	=head2 CHILD PROCESS WATCHERS
341		402
342	You can also watch on a child process exit and catch its exit status.	403	You can also watch on a child process exit and catch its exit status.
343		404
344	The child process is specified by the C<pid> argument (if set to C<0>, it	405	The child process is specified by the C<pid> argument (one some backends,
345	watches for any child process exit). The watcher will trigger as often	406	using C<0> watches for any child process exit, on others this will
346	as status change for the child are received. This works by installing a	407	croak). The watcher will be triggered only when the child process has
347	signal handler for C<SIGCHLD>. The callback will be called with the pid	408	finished and an exit status is available, not on any trace events
348	and exit status (as returned by waitpid), so unlike other watcher types,	409	(stopped/continued).
349	you I<can> rely on child watcher callback arguments.	410
		411	The callback will be called with the pid and exit status (as returned by
		412	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		413	callback arguments.
		414
		415	This watcher type works by installing a signal handler for C<SIGCHLD>,
		416	and since it cannot be shared, nothing else should use SIGCHLD or reap
		417	random child processes (waiting for specific child processes, e.g. inside
		418	C<system>, is just fine).
350		419
351	There is a slight catch to child watchers, however: you usually start them	420	There is a slight catch to child watchers, however: you usually start them
352	I<after> the child process was created, and this means the process could	421	I<after> the child process was created, and this means the process could
353	have exited already (and no SIGCHLD will be sent anymore).	422	have exited already (and no SIGCHLD will be sent anymore).
354		423
355	Not all event models handle this correctly (POE doesn't), but even for	424	Not all event models handle this correctly (neither POE nor IO::Async do,
		425	see their AnyEvent::Impl manpages for details), but even for event models
356	event models that I<do> handle this correctly, they usually need to be	426	that I<do> handle this correctly, they usually need to be loaded before
357	loaded before the process exits (i.e. before you fork in the first place).	427	the process exits (i.e. before you fork in the first place). AnyEvent's
		428	pure perl event loop handles all cases correctly regardless of when you
		429	start the watcher.
358		430
359	This means you cannot create a child watcher as the very first thing in an	431	This means you cannot create a child watcher as the very first
360	AnyEvent program, you I<have> to create at least one watcher before you	432	thing in an AnyEvent program, you I<have> to create at least one
361	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	433	watcher before you C<fork> the child (alternatively, you can call
		434	C<AnyEvent::detect>).
		435
		436	As most event loops do not support waiting for child events, they will be
		437	emulated by AnyEvent in most cases, in which the latency and race problems
		438	mentioned in the description of signal watchers apply.
362		439
363	Example: fork a process and wait for it	440	Example: fork a process and wait for it
364		441
365	my $done = AnyEvent->condvar;	442	my $done = AnyEvent->condvar;
366		443
…		…
376	);	453	);
377		454
378	# do something else, then wait for process exit	455	# do something else, then wait for process exit
379	$done->recv;	456	$done->recv;
380		457
		458	=head2 IDLE WATCHERS
		459
		460	Sometimes there is a need to do something, but it is not so important
		461	to do it instantly, but only when there is nothing better to do. This
		462	"nothing better to do" is usually defined to be "no other events need
		463	attention by the event loop".
		464
		465	Idle watchers ideally get invoked when the event loop has nothing
		466	better to do, just before it would block the process to wait for new
		467	events. Instead of blocking, the idle watcher is invoked.
		468
		469	Most event loops unfortunately do not really support idle watchers (only
		470	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		471	will simply call the callback "from time to time".
		472
		473	Example: read lines from STDIN, but only process them when the
		474	program is otherwise idle:
		475
		476	my @lines; # read data
		477	my $idle_w;
		478	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		479	push @lines, scalar <STDIN>;
		480
		481	# start an idle watcher, if not already done
		482	$idle_w ||= AnyEvent->idle (cb => sub {
		483	# handle only one line, when there are lines left
		484	if (my $line = shift @lines) {
		485	print "handled when idle: $line";
		486	} else {
		487	# otherwise disable the idle watcher again
		488	undef $idle_w;
		489	}
		490	});
		491	});
		492
381	=head2 CONDITION VARIABLES	493	=head2 CONDITION VARIABLES
382		494
383	If you are familiar with some event loops you will know that all of them	495	If you are familiar with some event loops you will know that all of them
384	require you to run some blocking "loop", "run" or similar function that	496	require you to run some blocking "loop", "run" or similar function that
385	will actively watch for new events and call your callbacks.	497	will actively watch for new events and call your callbacks.
386		498
387	AnyEvent is different, it expects somebody else to run the event loop and	499	AnyEvent is slightly different: it expects somebody else to run the event
388	will only block when necessary (usually when told by the user).	500	loop and will only block when necessary (usually when told by the user).
389		501
390	The instrument to do that is called a "condition variable", so called	502	The instrument to do that is called a "condition variable", so called
391	because they represent a condition that must become true.	503	because they represent a condition that must become true.
392		504
		505	Now is probably a good time to look at the examples further below.
		506
393	Condition variables can be created by calling the C<< AnyEvent->condvar	507	Condition variables can be created by calling the C<< AnyEvent->condvar
394	>> method, usually without arguments. The only argument pair allowed is	508	>> method, usually without arguments. The only argument pair allowed is
395
396	C<cb>, which specifies a callback to be called when the condition variable	509	C<cb>, which specifies a callback to be called when the condition variable
397	becomes true, with the condition variable as the first argument (but not	510	becomes true, with the condition variable as the first argument (but not
398	the results).	511	the results).
399		512
400	After creation, the condition variable is "false" until it becomes "true"	513	After creation, the condition variable is "false" until it becomes "true"
…		…
405	Condition variables are similar to callbacks, except that you can	518	Condition variables are similar to callbacks, except that you can
406	optionally wait for them. They can also be called merge points - points	519	optionally wait for them. They can also be called merge points - points
407	in time where multiple outstanding events have been processed. And yet	520	in time where multiple outstanding events have been processed. And yet
408	another way to call them is transactions - each condition variable can be	521	another way to call them is transactions - each condition variable can be
409	used to represent a transaction, which finishes at some point and delivers	522	used to represent a transaction, which finishes at some point and delivers
410	a result.	523	a result. And yet some people know them as "futures" - a promise to
		524	compute/deliver something that you can wait for.
411		525
412	Condition variables are very useful to signal that something has finished,	526	Condition variables are very useful to signal that something has finished,
413	for example, if you write a module that does asynchronous http requests,	527	for example, if you write a module that does asynchronous http requests,
414	then a condition variable would be the ideal candidate to signal the	528	then a condition variable would be the ideal candidate to signal the
415	availability of results. The user can either act when the callback is	529	availability of results. The user can either act when the callback is
…		…
449	after => 1,	563	after => 1,
450	cb => sub { $result_ready->send },	564	cb => sub { $result_ready->send },
451	);	565	);
452		566
453	# this "blocks" (while handling events) till the callback	567	# this "blocks" (while handling events) till the callback
454	# calls send	568	# calls -<send
455	$result_ready->recv;	569	$result_ready->recv;
456		570
457	Example: wait for a timer, but take advantage of the fact that	571	Example: wait for a timer, but take advantage of the fact that condition
458	condition variables are also code references.	572	variables are also callable directly.
459		573
460	my $done = AnyEvent->condvar;	574	my $done = AnyEvent->condvar;
461	my $delay = AnyEvent->timer (after => 5, cb => $done);	575	my $delay = AnyEvent->timer (after => 5, cb => $done);
462	$done->recv;	576	$done->recv;
463		577
…		…
469		583
470	...	584	...
471		585
472	my @info = $couchdb->info->recv;	586	my @info = $couchdb->info->recv;
473		587
474	And this is how you would just ste a callback to be called whenever the	588	And this is how you would just set a callback to be called whenever the
475	results are available:	589	results are available:
476		590
477	$couchdb->info->cb (sub {	591	$couchdb->info->cb (sub {
478	my @info = $_[0]->recv;	592	my @info = $_[0]->recv;
479	});	593	});
…		…
497	immediately from within send.	611	immediately from within send.
498		612
499	Any arguments passed to the C<send> call will be returned by all	613	Any arguments passed to the C<send> call will be returned by all
500	future C<< ->recv >> calls.	614	future C<< ->recv >> calls.
501		615
502	Condition variables are overloaded so one can call them directly	616	Condition variables are overloaded so one can call them directly (as if
503	(as a code reference). Calling them directly is the same as calling	617	they were a code reference). Calling them directly is the same as calling
504	C<send>. Note, however, that many C-based event loops do not handle	618	C<send>.
505	overloading, so as tempting as it may be, passing a condition variable
506	instead of a callback does not work. Both the pure perl and EV loops
507	support overloading, however, as well as all functions that use perl to
508	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
509	example).
510		619
511	=item $cv->croak ($error)	620	=item $cv->croak ($error)
512		621
513	Similar to send, but causes all call's to C<< ->recv >> to invoke	622	Similar to send, but causes all call's to C<< ->recv >> to invoke
514	C<Carp::croak> with the given error message/object/scalar.	623	C<Carp::croak> with the given error message/object/scalar.
515		624
516	This can be used to signal any errors to the condition variable	625	This can be used to signal any errors to the condition variable
517	user/consumer.	626	user/consumer. Doing it this way instead of calling C<croak> directly
		627	delays the error detetcion, but has the overwhelmign advantage that it
		628	diagnoses the error at the place where the result is expected, and not
		629	deep in some event clalback without connection to the actual code causing
		630	the problem.
518		631
519	=item $cv->begin ([group callback])	632	=item $cv->begin ([group callback])
520		633
521	=item $cv->end	634	=item $cv->end
522
523	These two methods are EXPERIMENTAL and MIGHT CHANGE.
524		635
525	These two methods can be used to combine many transactions/events into	636	These two methods can be used to combine many transactions/events into
526	one. For example, a function that pings many hosts in parallel might want	637	one. For example, a function that pings many hosts in parallel might want
527	to use a condition variable for the whole process.	638	to use a condition variable for the whole process.
528		639
…		…
530	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	641	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
531	>>, the (last) callback passed to C<begin> will be executed. That callback	642	>>, the (last) callback passed to C<begin> will be executed. That callback
532	is I<supposed> to call C<< ->send >>, but that is not required. If no	643	is I<supposed> to call C<< ->send >>, but that is not required. If no
533	callback was set, C<send> will be called without any arguments.	644	callback was set, C<send> will be called without any arguments.
534		645
535	Let's clarify this with the ping example:	646	You can think of C<< $cv->send >> giving you an OR condition (one call
		647	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		648	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		649
		650	Let's start with a simple example: you have two I/O watchers (for example,
		651	STDOUT and STDERR for a program), and you want to wait for both streams to
		652	close before activating a condvar:
		653
		654	my $cv = AnyEvent->condvar;
		655
		656	$cv->begin; # first watcher
		657	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		658	defined sysread $fh1, my $buf, 4096
		659	or $cv->end;
		660	});
		661
		662	$cv->begin; # second watcher
		663	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		664	defined sysread $fh2, my $buf, 4096
		665	or $cv->end;
		666	});
		667
		668	$cv->recv;
		669
		670	This works because for every event source (EOF on file handle), there is
		671	one call to C<begin>, so the condvar waits for all calls to C<end> before
		672	sending.
		673
		674	The ping example mentioned above is slightly more complicated, as the
		675	there are results to be passwd back, and the number of tasks that are
		676	begung can potentially be zero:
536		677
537	my $cv = AnyEvent->condvar;	678	my $cv = AnyEvent->condvar;
538		679
539	my %result;	680	my %result;
540	$cv->begin (sub { $cv->send (\%result) });	681	$cv->begin (sub { $cv->send (\%result) });
…		…
560	loop, which serves two important purposes: first, it sets the callback	701	loop, which serves two important purposes: first, it sets the callback
561	to be called once the counter reaches C<0>, and second, it ensures that	702	to be called once the counter reaches C<0>, and second, it ensures that
562	C<send> is called even when C<no> hosts are being pinged (the loop	703	C<send> is called even when C<no> hosts are being pinged (the loop
563	doesn't execute once).	704	doesn't execute once).
564		705
565	This is the general pattern when you "fan out" into multiple subrequests:	706	This is the general pattern when you "fan out" into multiple (but
566	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	707	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
567	is called at least once, and then, for each subrequest you start, call	708	the callback and ensure C<end> is called at least once, and then, for each
568	C<begin> and for each subrequest you finish, call C<end>.	709	subrequest you start, call C<begin> and for each subrequest you finish,
		710	call C<end>.
569		711
570	=back	712	=back
571		713
572	=head3 METHODS FOR CONSUMERS	714	=head3 METHODS FOR CONSUMERS
573		715
…		…
589	function will call C<croak>.	731	function will call C<croak>.
590		732
591	In list context, all parameters passed to C<send> will be returned,	733	In list context, all parameters passed to C<send> will be returned,
592	in scalar context only the first one will be returned.	734	in scalar context only the first one will be returned.
593		735
		736	Note that doing a blocking wait in a callback is not supported by any
		737	event loop, that is, recursive invocation of a blocking C<< ->recv
		738	>> is not allowed, and the C<recv> call will C<croak> if such a
		739	condition is detected. This condition can be slightly loosened by using
		740	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		741	any thread that doesn't run the event loop itself.
		742
594	Not all event models support a blocking wait - some die in that case	743	Not all event models support a blocking wait - some die in that case
595	(programs might want to do that to stay interactive), so I<if you are	744	(programs might want to do that to stay interactive), so I<if you are
596	using this from a module, never require a blocking wait>, but let the	745	using this from a module, never require a blocking wait>. Instead, let the
597	caller decide whether the call will block or not (for example, by coupling	746	caller decide whether the call will block or not (for example, by coupling
598	condition variables with some kind of request results and supporting	747	condition variables with some kind of request results and supporting
599	callbacks so the caller knows that getting the result will not block,	748	callbacks so the caller knows that getting the result will not block,
600	while still supporting blocking waits if the caller so desires).	749	while still supporting blocking waits if the caller so desires).
601		750
602	Another reason I<never> to C<< ->recv >> in a module is that you cannot
603	sensibly have two C<< ->recv >>'s in parallel, as that would require
604	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
605	can supply.
606
607	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
608	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
609	versions and also integrates coroutines into AnyEvent, making blocking
610	C<< ->recv >> calls perfectly safe as long as they are done from another
611	coroutine (one that doesn't run the event loop).
612
613	You can ensure that C<< -recv >> never blocks by setting a callback and	751	You can ensure that C<< -recv >> never blocks by setting a callback and
614	only calling C<< ->recv >> from within that callback (or at a later	752	only calling C<< ->recv >> from within that callback (or at a later
615	time). This will work even when the event loop does not support blocking	753	time). This will work even when the event loop does not support blocking
616	waits otherwise.	754	waits otherwise.
617		755
…		…
630	variable itself. Calling C<recv> inside the callback or at any later time	768	variable itself. Calling C<recv> inside the callback or at any later time
631	is guaranteed not to block.	769	is guaranteed not to block.
632		770
633	=back	771	=back
634		772
		773	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		774
		775	The available backend classes are (every class has its own manpage):
		776
		777	=over 4
		778
		779	=item Backends that are autoprobed when no other event loop can be found.
		780
		781	EV is the preferred backend when no other event loop seems to be in
		782	use. If EV is not installed, then AnyEvent will try Event, and, failing
		783	that, will fall back to its own pure-perl implementation, which is
		784	available everywhere as it comes with AnyEvent itself.
		785
		786	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		787	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		788	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		789
		790	=item Backends that are transparently being picked up when they are used.
		791
		792	These will be used when they are currently loaded when the first watcher
		793	is created, in which case it is assumed that the application is using
		794	them. This means that AnyEvent will automatically pick the right backend
		795	when the main program loads an event module before anything starts to
		796	create watchers. Nothing special needs to be done by the main program.
		797
		798	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		799	AnyEvent::Impl::Tk based on Tk, very broken.
		800	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		801	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		802	AnyEvent::Impl::Irssi used when running within irssi.
		803
		804	=item Backends with special needs.
		805
		806	Qt requires the Qt::Application to be instantiated first, but will
		807	otherwise be picked up automatically. As long as the main program
		808	instantiates the application before any AnyEvent watchers are created,
		809	everything should just work.
		810
		811	AnyEvent::Impl::Qt based on Qt.
		812
		813	Support for IO::Async can only be partial, as it is too broken and
		814	architecturally limited to even support the AnyEvent API. It also
		815	is the only event loop that needs the loop to be set explicitly, so
		816	it can only be used by a main program knowing about AnyEvent. See
		817	L<AnyEvent::Impl::Async> for the gory details.
		818
		819	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		820
		821	=item Event loops that are indirectly supported via other backends.
		822
		823	Some event loops can be supported via other modules:
		824
		825	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		826
		827	B<WxWidgets> has no support for watching file handles. However, you can
		828	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		829	polls 20 times per second, which was considered to be too horrible to even
		830	consider for AnyEvent.
		831
		832	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		833	backend, so it can be supported through POE.
		834
		835	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		836	load L<POE> when detecting them, in the hope that POE will pick them up,
		837	in which case everything will be automatic.
		838
		839	=back
		840
635	=head1 GLOBAL VARIABLES AND FUNCTIONS	841	=head1 GLOBAL VARIABLES AND FUNCTIONS
636		842
		843	These are not normally required to use AnyEvent, but can be useful to
		844	write AnyEvent extension modules.
		845
637	=over 4	846	=over 4
638		847
639	=item $AnyEvent::MODEL	848	=item $AnyEvent::MODEL
640		849
641	Contains C<undef> until the first watcher is being created. Then it	850	Contains C<undef> until the first watcher is being created, before the
		851	backend has been autodetected.
		852
642	contains the event model that is being used, which is the name of the	853	Afterwards it contains the event model that is being used, which is the
643	Perl class implementing the model. This class is usually one of the	854	name of the Perl class implementing the model. This class is usually one
644	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	855	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
645	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	856	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
646		857	will be C<urxvt::anyevent>).
647	The known classes so far are:
648
649	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
650	AnyEvent::Impl::Event based on Event, second best choice.
651	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
652	AnyEvent::Impl::Glib based on Glib, third-best choice.
653	AnyEvent::Impl::Tk based on Tk, very bad choice.
654	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
655	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
656	AnyEvent::Impl::POE based on POE, not generic enough for full support.
657
658	There is no support for WxWidgets, as WxWidgets has no support for
659	watching file handles. However, you can use WxWidgets through the
660	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
661	second, which was considered to be too horrible to even consider for
662	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
663	it's adaptor.
664
665	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
666	autodetecting them.
667		858
668	=item AnyEvent::detect	859	=item AnyEvent::detect
669		860
670	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	861	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
671	if necessary. You should only call this function right before you would	862	if necessary. You should only call this function right before you would
672	have created an AnyEvent watcher anyway, that is, as late as possible at	863	have created an AnyEvent watcher anyway, that is, as late as possible at
673	runtime.	864	runtime, and not e.g. while initialising of your module.
		865
		866	If you need to do some initialisation before AnyEvent watchers are
		867	created, use C<post_detect>.
674		868
675	=item $guard = AnyEvent::post_detect { BLOCK }	869	=item $guard = AnyEvent::post_detect { BLOCK }
676		870
677	Arranges for the code block to be executed as soon as the event model is	871	Arranges for the code block to be executed as soon as the event model is
678	autodetected (or immediately if this has already happened).	872	autodetected (or immediately if this has already happened).
679		873
		874	The block will be executed I<after> the actual backend has been detected
		875	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		876	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		877	other initialisations - see the sources of L<AnyEvent::Strict> or
		878	L<AnyEvent::AIO> to see how this is used.
		879
		880	The most common usage is to create some global watchers, without forcing
		881	event module detection too early, for example, L<AnyEvent::AIO> creates
		882	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		883	avoid autodetecting the event module at load time.
		884
680	If called in scalar or list context, then it creates and returns an object	885	If called in scalar or list context, then it creates and returns an object
681	that automatically removes the callback again when it is destroyed. See	886	that automatically removes the callback again when it is destroyed (or
		887	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
682	L<Coro::BDB> for a case where this is useful.	888	a case where this is useful.
		889
		890	Example: Create a watcher for the IO::AIO module and store it in
		891	C<$WATCHER>. Only do so after the event loop is initialised, though.
		892
		893	our WATCHER;
		894
		895	my $guard = AnyEvent::post_detect {
		896	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		897	};
		898
		899	# the ||= is important in case post_detect immediately runs the block,
		900	# as to not clobber the newly-created watcher. assigning both watcher and
		901	# post_detect guard to the same variable has the advantage of users being
		902	# able to just C<undef $WATCHER> if the watcher causes them grief.
		903
		904	$WATCHER ||= $guard;
683		905
684	=item @AnyEvent::post_detect	906	=item @AnyEvent::post_detect
685		907
686	If there are any code references in this array (you can C<push> to it	908	If there are any code references in this array (you can C<push> to it
687	before or after loading AnyEvent), then they will called directly after	909	before or after loading AnyEvent), then they will called directly after
688	the event loop has been chosen.	910	the event loop has been chosen.
689		911
690	You should check C<$AnyEvent::MODEL> before adding to this array, though:	912	You should check C<$AnyEvent::MODEL> before adding to this array, though:
691	if it contains a true value then the event loop has already been detected,	913	if it is defined then the event loop has already been detected, and the
692	and the array will be ignored.	914	array will be ignored.
693		915
694	Best use C<AnyEvent::post_detect { BLOCK }> instead.	916	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		917	it,as it takes care of these details.
		918
		919	This variable is mainly useful for modules that can do something useful
		920	when AnyEvent is used and thus want to know when it is initialised, but do
		921	not need to even load it by default. This array provides the means to hook
		922	into AnyEvent passively, without loading it.
695		923
696	=back	924	=back
697		925
698	=head1 WHAT TO DO IN A MODULE	926	=head1 WHAT TO DO IN A MODULE
699		927
…		…
754		982
755		983
756	=head1 OTHER MODULES	984	=head1 OTHER MODULES
757		985
758	The following is a non-exhaustive list of additional modules that use	986	The following is a non-exhaustive list of additional modules that use
759	AnyEvent and can therefore be mixed easily with other AnyEvent modules	987	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
760	in the same program. Some of the modules come with AnyEvent, some are	988	modules and other event loops in the same program. Some of the modules
761	available via CPAN.	989	come with AnyEvent, most are available via CPAN.
762		990
763	=over 4	991	=over 4
764		992
765	=item L<AnyEvent::Util>	993	=item L<AnyEvent::Util>
766		994
…		…
775		1003
776	=item L<AnyEvent::Handle>	1004	=item L<AnyEvent::Handle>
777		1005
778	Provide read and write buffers, manages watchers for reads and writes,	1006	Provide read and write buffers, manages watchers for reads and writes,
779	supports raw and formatted I/O, I/O queued and fully transparent and	1007	supports raw and formatted I/O, I/O queued and fully transparent and
780	non-blocking SSL/TLS.	1008	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
781		1009
782	=item L<AnyEvent::DNS>	1010	=item L<AnyEvent::DNS>
783		1011
784	Provides rich asynchronous DNS resolver capabilities.	1012	Provides rich asynchronous DNS resolver capabilities.
785		1013
…		…
813		1041
814	=item L<AnyEvent::GPSD>	1042	=item L<AnyEvent::GPSD>
815		1043
816	A non-blocking interface to gpsd, a daemon delivering GPS information.	1044	A non-blocking interface to gpsd, a daemon delivering GPS information.
817		1045
		1046	=item L<AnyEvent::IRC>
		1047
		1048	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1049
		1050	=item L<AnyEvent::XMPP>
		1051
		1052	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1053	Net::XMPP2>.
		1054
818	=item L<AnyEvent::IGS>	1055	=item L<AnyEvent::IGS>
819		1056
820	A non-blocking interface to the Internet Go Server protocol (used by	1057	A non-blocking interface to the Internet Go Server protocol (used by
821	L<App::IGS>).	1058	L<App::IGS>).
822		1059
823	=item L<Net::IRC3>
824
825	AnyEvent based IRC client module family.
826
827	=item L<Net::XMPP2>
828
829	AnyEvent based XMPP (Jabber protocol) module family.
830
831	=item L<Net::FCP>	1060	=item L<Net::FCP>
832		1061
833	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1062	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
834	of AnyEvent.	1063	of AnyEvent.
835		1064
…		…
839		1068
840	=item L<Coro>	1069	=item L<Coro>
841		1070
842	Has special support for AnyEvent via L<Coro::AnyEvent>.	1071	Has special support for AnyEvent via L<Coro::AnyEvent>.
843		1072
844	=item L<IO::Lambda>
845
846	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
847
848	=back	1073	=back
849		1074
850	=cut	1075	=cut
851		1076
852	package AnyEvent;	1077	package AnyEvent;
853		1078
		1079	# basically a tuned-down version of common::sense
		1080	sub common_sense {
854	no warnings;	1081	# no warnings
		1082	${^WARNING_BITS} ^= ${^WARNING_BITS};
855	use strict qw(vars subs);	1083	# use strict vars subs
		1084	$^H |= 0x00000600;
		1085	}
856		1086
		1087	BEGIN { AnyEvent::common_sense }
		1088
857	use Carp;	1089	use Carp ();
858		1090
859	our $VERSION = 4.233;	1091	our $VERSION = 4.881;
860	our $MODEL;	1092	our $MODEL;
861		1093
862	our $AUTOLOAD;	1094	our $AUTOLOAD;
863	our @ISA;	1095	our @ISA;
864		1096
865	our @REGISTRY;	1097	our @REGISTRY;
866		1098
867	our $WIN32;	1099	our $WIN32;
868		1100
		1101	our $VERBOSE;
		1102
869	BEGIN {	1103	BEGIN {
870	my $win32 = ! ! ($^O =~ /mswin32/i);	1104	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
871	eval "sub WIN32(){ $win32 }";	1105	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
872	}
873		1106
		1107	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1108	if ${^TAINT};
		1109
874	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1110	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1111
		1112	}
		1113
		1114	our $MAX_SIGNAL_LATENCY = 10;
875		1115
876	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1116	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
877		1117
878	{	1118	{
879	my $idx;	1119	my $idx;
…		…
881	for reverse split /\s*,\s*/,	1121	for reverse split /\s*,\s*/,
882	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1122	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
883	}	1123	}
884		1124
885	my @models = (	1125	my @models = (
886	[EV:: => AnyEvent::Impl::EV::],	1126	[EV:: => AnyEvent::Impl::EV:: , 1],
887	[Event:: => AnyEvent::Impl::Event::],	1127	[Event:: => AnyEvent::Impl::Event::, 1],
888	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1128	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
889	# everything below here will not be autoprobed	1129	# everything below here will not (normally) be autoprobed
890	# as the pureperl backend should work everywhere	1130	# as the pureperl backend should work everywhere
891	# and is usually faster	1131	# and is usually faster
		1132	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1133	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1134	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
892	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1135	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
893	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
894	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
895	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1136	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
896	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1137	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
897	[Wx:: => AnyEvent::Impl::POE::],	1138	[Wx:: => AnyEvent::Impl::POE::],
898	[Prima:: => AnyEvent::Impl::POE::],	1139	[Prima:: => AnyEvent::Impl::POE::],
		1140	# IO::Async is just too broken - we would need workarounds for its
		1141	# byzantine signal and broken child handling, among others.
		1142	# IO::Async is rather hard to detect, as it doesn't have any
		1143	# obvious default class.
		1144	# [0, IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1145	# [0, IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1146	# [0, IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
899	);	1147	);
900		1148
901	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1149	our %method = map +($_ => 1),
		1150	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
902		1151
903	our @post_detect;	1152	our @post_detect;
904		1153
905	sub post_detect(&) {	1154	sub post_detect(&) {
906	my ($cb) = @_;	1155	my ($cb) = @_;
907		1156
908	if ($MODEL) {	1157	if ($MODEL) {
909	$cb->();	1158	$cb->();
910		1159
911	1	1160	undef
912	} else {	1161	} else {
913	push @post_detect, $cb;	1162	push @post_detect, $cb;
914		1163
915	defined wantarray	1164	defined wantarray
916	? bless \$cb, "AnyEvent::Util::PostDetect"	1165	? bless \$cb, "AnyEvent::Util::postdetect"
917	: ()	1166	: ()
918	}	1167	}
919	}	1168	}
920		1169
921	sub AnyEvent::Util::PostDetect::DESTROY {	1170	sub AnyEvent::Util::postdetect::DESTROY {
922	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1171	@post_detect = grep $_ != ${$_[0]}, @post_detect;
923	}	1172	}
924		1173
925	sub detect() {	1174	sub detect() {
926	unless ($MODEL) {	1175	unless ($MODEL) {
927	no strict 'refs';
928	local $SIG{__DIE__};	1176	local $SIG{__DIE__};
929		1177
930	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1178	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
931	my $model = "AnyEvent::Impl::$1";	1179	my $model = "AnyEvent::Impl::$1";
932	if (eval "require $model") {	1180	if (eval "require $model") {
933	$MODEL = $model;	1181	$MODEL = $model;
934	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1182	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
935	} else {	1183	} else {
936	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1184	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
937	}	1185	}
938	}	1186	}
939		1187
940	# check for already loaded models	1188	# check for already loaded models
941	unless ($MODEL) {	1189	unless ($MODEL) {
942	for (@REGISTRY, @models) {	1190	for (@REGISTRY, @models) {
943	my ($package, $model) = @$_;	1191	my ($package, $model) = @$_;
944	if (${"$package\::VERSION"} > 0) {	1192	if (${"$package\::VERSION"} > 0) {
945	if (eval "require $model") {	1193	if (eval "require $model") {
946	$MODEL = $model;	1194	$MODEL = $model;
947	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1195	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
948	last;	1196	last;
949	}	1197	}
950	}	1198	}
951	}	1199	}
952		1200
953	unless ($MODEL) {	1201	unless ($MODEL) {
954	# try to load a model	1202	# try to autoload a model
955
956	for (@REGISTRY, @models) {	1203	for (@REGISTRY, @models) {
957	my ($package, $model) = @$_;	1204	my ($package, $model, $autoload) = @$_;
		1205	if (
		1206	$autoload
958	if (eval "require $package"	1207	and eval "require $package"
959	and ${"$package\::VERSION"} > 0	1208	and ${"$package\::VERSION"} > 0
960	and eval "require $model") {	1209	and eval "require $model"
		1210	) {
961	$MODEL = $model;	1211	$MODEL = $model;
962	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1212	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
963	last;	1213	last;
964	}	1214	}
965	}	1215	}
966		1216
967	$MODEL	1217	$MODEL
968	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1218	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
969	}	1219	}
970	}	1220	}
971		1221
972	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1222	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
973		1223
…		…
983		1233
984	sub AUTOLOAD {	1234	sub AUTOLOAD {
985	(my $func = $AUTOLOAD) =~ s/.*://;	1235	(my $func = $AUTOLOAD) =~ s/.*://;
986		1236
987	$method{$func}	1237	$method{$func}
988	or croak "$func: not a valid method for AnyEvent objects";	1238	or Carp::croak "$func: not a valid method for AnyEvent objects";
989		1239
990	detect unless $MODEL;	1240	detect unless $MODEL;
991		1241
992	my $class = shift;	1242	my $class = shift;
993	$class->$func (@_);	1243	$class->$func (@_);
994	}	1244	}
995		1245
996	# utility function to dup a filehandle. this is used by many backends	1246	# utility function to dup a filehandle. this is used by many backends
997	# to support binding more than one watcher per filehandle (they usually	1247	# to support binding more than one watcher per filehandle (they usually
998	# allow only one watcher per fd, so we dup it to get a different one).	1248	# allow only one watcher per fd, so we dup it to get a different one).
999	sub _dupfh($$$$) {	1249	sub _dupfh($$;$$) {
1000	my ($poll, $fh, $r, $w) = @_;	1250	my ($poll, $fh, $r, $w) = @_;
1001		1251
1002	require Fcntl;
1003
1004	# cygwin requires the fh mode to be matching, unix doesn't	1252	# cygwin requires the fh mode to be matching, unix doesn't
1005	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1253	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1006	: $poll eq "w" ? ($w, ">")
1007	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1008		1254
1009	open my $fh2, "$mode&" . fileno $fh	1255	open my $fh2, $mode, $fh
1010	or die "cannot dup() filehandle: $!";	1256	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1011		1257
1012	# we assume CLOEXEC is already set by perl in all important cases	1258	# we assume CLOEXEC is already set by perl in all important cases
1013		1259
1014	($fh2, $rw)	1260	($fh2, $rw)
1015	}	1261	}
1016		1262
1017	package AnyEvent::Base;	1263	package AnyEvent::Base;
1018		1264
1019	# default implementation for now and time	1265	# default implementations for many methods
1020		1266
1021	BEGIN {	1267	sub _time {
		1268	# probe for availability of Time::HiRes
1022	if (eval "use Time::HiRes (); time (); 1") {	1269	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1270	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1023	*_time = \&Time::HiRes::time;	1271	*_time = \&Time::HiRes::time;
1024	# if (eval "use POSIX (); (POSIX::times())...	1272	# if (eval "use POSIX (); (POSIX::times())...
1025	} else {	1273	} else {
		1274	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1026	*_time = \&CORE::time; # epic fail	1275	*_time = sub { time }; # epic fail
1027	}	1276	}
		1277
		1278	&_time
1028	}	1279	}
1029		1280
1030	sub time { _time }	1281	sub time { _time }
1031	sub now { _time }	1282	sub now { _time }
		1283	sub now_update { }
1032		1284
1033	# default implementation for ->condvar	1285	# default implementation for ->condvar
1034		1286
1035	sub condvar {	1287	sub condvar {
1036	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1288	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1037	}	1289	}
1038		1290
1039	# default implementation for ->signal	1291	# default implementation for ->signal
1040		1292
1041	our %SIG_CB;	1293	our $HAVE_ASYNC_INTERRUPT;
		1294	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1295	our (%SIG_ASY, %SIG_ASY_W);
		1296	our ($SIG_COUNT, $SIG_TW);
1042		1297
		1298	sub _signal_exec {
		1299	$HAVE_ASYNC_INTERRUPT
		1300	? $SIGPIPE_R->drain
		1301	: sysread $SIGPIPE_R, my $dummy, 9;
		1302
		1303	while (%SIG_EV) {
		1304	for (keys %SIG_EV) {
		1305	delete $SIG_EV{$_};
		1306	$_->() for values %{ $SIG_CB{$_} || {} };
		1307	}
		1308	}
		1309	}
		1310
		1311	# install a dummy wakeup watcher to reduce signal catching latency
		1312	sub _sig_add() {
		1313	unless ($SIG_COUNT++) {
		1314	# try to align timer on a full-second boundary, if possible
		1315	my $NOW = AnyEvent->now;
		1316
		1317	$SIG_TW = AnyEvent->timer (
		1318	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1319	interval => $MAX_SIGNAL_LATENCY,
		1320	cb => sub { }, # just for the PERL_ASYNC_CHECK
		1321	);
		1322	}
		1323	}
		1324
		1325	sub _sig_del {
		1326	undef $SIG_TW
		1327	unless --$SIG_COUNT;
		1328	}
		1329
1043	sub signal {	1330	sub _signal {
1044	my (undef, %arg) = @_;	1331	my (undef, %arg) = @_;
1045		1332
1046	my $signal = uc $arg{signal}	1333	my $signal = uc $arg{signal}
1047	or Carp::croak "required option 'signal' is missing";	1334	or Carp::croak "required option 'signal' is missing";
1048		1335
		1336	if ($HAVE_ASYNC_INTERRUPT) {
		1337	# async::interrupt
		1338
		1339	$signal = Async::Interrupt::sig2num ($signal);
1049	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1340	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1341
		1342	$SIG_ASY{$signal} ||= new Async::Interrupt
		1343	cb => sub { undef $SIG_EV{$signal} },
		1344	signal => $signal,
		1345	pipe => [$SIGPIPE_R->filenos],
		1346	pipe_autodrain => 0,
		1347	;
		1348
		1349	} else {
		1350	# pure perl
		1351
		1352	# AE::Util has been loaded in signal
		1353	$signal = AnyEvent::Util::sig2name ($signal);
		1354	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1355
1050	$SIG{$signal} ||= sub {	1356	$SIG{$signal} ||= sub {
1051	$_->() for values %{ $SIG_CB{$signal} || {} };	1357	local $!;
		1358	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1359	undef $SIG_EV{$signal};
		1360	};
		1361
		1362	# can't do signal processing without introducing races in pure perl,
		1363	# so limit the signal latency.
		1364	_sig_add;
1052	};	1365	}
1053		1366
1054	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1367	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1055	}	1368	}
1056		1369
		1370	sub signal {
		1371	# probe for availability of Async::Interrupt
		1372	if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 1.0 (); 1") {
		1373	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
		1374
		1375	$HAVE_ASYNC_INTERRUPT = 1;
		1376	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1377	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
		1378
		1379	} else {
		1380	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1381
		1382	require Fcntl;
		1383
		1384	if (AnyEvent::WIN32) {
		1385	require AnyEvent::Util;
		1386
		1387	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1388	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1389	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1390	} else {
		1391	pipe $SIGPIPE_R, $SIGPIPE_W;
		1392	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1393	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1394
		1395	# not strictly required, as $^F is normally 2, but let's make sure...
		1396	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1397	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1398	}
		1399
		1400	$SIGPIPE_R
		1401	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1402
		1403	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1404	}
		1405
		1406	*signal = \&_signal;
		1407	&signal
		1408	}
		1409
1057	sub AnyEvent::Base::Signal::DESTROY {	1410	sub AnyEvent::Base::signal::DESTROY {
1058	my ($signal, $cb) = @{$_[0]};	1411	my ($signal, $cb) = @{$_[0]};
1059		1412
		1413	_sig_del;
		1414
1060	delete $SIG_CB{$signal}{$cb};	1415	delete $SIG_CB{$signal}{$cb};
1061		1416
		1417	$HAVE_ASYNC_INTERRUPT
		1418	? delete $SIG_ASY{$signal}
		1419	: # delete doesn't work with older perls - they then
		1420	# print weird messages, or just unconditionally exit
		1421	# instead of getting the default action.
		1422	undef $SIG{$signal}
1062	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };	1423	unless keys %{ $SIG_CB{$signal} };
1063	}	1424	}
1064		1425
1065	# default implementation for ->child	1426	# default implementation for ->child
1066		1427
1067	our %PID_CB;	1428	our %PID_CB;
1068	our $CHLD_W;	1429	our $CHLD_W;
1069	our $CHLD_DELAY_W;	1430	our $CHLD_DELAY_W;
1070	our $PID_IDLE;
1071	our $WNOHANG;	1431	our $WNOHANG;
1072		1432
1073	sub _child_wait {	1433	sub _emit_childstatus($$) {
1074	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1434	my (undef, $rpid, $rstatus) = @_;
		1435
		1436	$_->($rpid, $rstatus)
1075	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1437	for values %{ $PID_CB{$rpid} || {} },
1076	(values %{ $PID_CB{0} || {} });	1438	values %{ $PID_CB{0} || {} };
1077	}
1078
1079	undef $PID_IDLE;
1080	}	1439	}
1081		1440
1082	sub _sigchld {	1441	sub _sigchld {
1083	# make sure we deliver these changes "synchronous" with the event loop.	1442	my $pid;
1084	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {	1443
1085	undef $CHLD_DELAY_W;	1444	AnyEvent->_emit_childstatus ($pid, $?)
1086	&_child_wait;	1445	while ($pid = waitpid -1, $WNOHANG) > 0;
1087	});
1088	}	1446	}
1089		1447
1090	sub child {	1448	sub child {
1091	my (undef, %arg) = @_;	1449	my (undef, %arg) = @_;
1092		1450
1093	defined (my $pid = $arg{pid} + 0)	1451	defined (my $pid = $arg{pid} + 0)
1094	or Carp::croak "required option 'pid' is missing";	1452	or Carp::croak "required option 'pid' is missing";
1095		1453
1096	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1454	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1097		1455
1098	unless ($WNOHANG) {	1456	# WNOHANG is almost cetrainly 1 everywhere
		1457	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1458	? 1
1099	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1459	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1100	}
1101		1460
1102	unless ($CHLD_W) {	1461	unless ($CHLD_W) {
1103	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1462	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1104	# child could be a zombie already, so make at least one round	1463	# child could be a zombie already, so make at least one round
1105	&_sigchld;	1464	&_sigchld;
1106	}	1465	}
1107		1466
1108	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1467	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1109	}	1468	}
1110		1469
1111	sub AnyEvent::Base::Child::DESTROY {	1470	sub AnyEvent::Base::child::DESTROY {
1112	my ($pid, $cb) = @{$_[0]};	1471	my ($pid, $cb) = @{$_[0]};
1113		1472
1114	delete $PID_CB{$pid}{$cb};	1473	delete $PID_CB{$pid}{$cb};
1115	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1474	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1116		1475
1117	undef $CHLD_W unless keys %PID_CB;	1476	undef $CHLD_W unless keys %PID_CB;
1118	}	1477	}
1119		1478
		1479	# idle emulation is done by simply using a timer, regardless
		1480	# of whether the process is idle or not, and not letting
		1481	# the callback use more than 50% of the time.
		1482	sub idle {
		1483	my (undef, %arg) = @_;
		1484
		1485	my ($cb, $w, $rcb) = $arg{cb};
		1486
		1487	$rcb = sub {
		1488	if ($cb) {
		1489	$w = _time;
		1490	&$cb;
		1491	$w = _time - $w;
		1492
		1493	# never use more then 50% of the time for the idle watcher,
		1494	# within some limits
		1495	$w = 0.0001 if $w < 0.0001;
		1496	$w = 5 if $w > 5;
		1497
		1498	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1499	} else {
		1500	# clean up...
		1501	undef $w;
		1502	undef $rcb;
		1503	}
		1504	};
		1505
		1506	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1507
		1508	bless \\$cb, "AnyEvent::Base::idle"
		1509	}
		1510
		1511	sub AnyEvent::Base::idle::DESTROY {
		1512	undef $${$_[0]};
		1513	}
		1514
1120	package AnyEvent::CondVar;	1515	package AnyEvent::CondVar;
1121		1516
1122	our @ISA = AnyEvent::CondVar::Base::;	1517	our @ISA = AnyEvent::CondVar::Base::;
1123		1518
1124	package AnyEvent::CondVar::Base;	1519	package AnyEvent::CondVar::Base;
1125		1520
1126	use overload	1521	#use overload
1127	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1522	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1128	fallback => 1;	1523	# fallback => 1;
		1524
		1525	# save 300+ kilobytes by dirtily hardcoding overloading
		1526	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1527	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1528	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1529	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1530
		1531	our $WAITING;
1129		1532
1130	sub _send {	1533	sub _send {
1131	# nop	1534	# nop
1132	}	1535	}
1133		1536
…		…
1146	sub ready {	1549	sub ready {
1147	$_[0]{_ae_sent}	1550	$_[0]{_ae_sent}
1148	}	1551	}
1149		1552
1150	sub _wait {	1553	sub _wait {
		1554	$WAITING
		1555	and !$_[0]{_ae_sent}
		1556	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1557
		1558	local $WAITING = 1;
1151	AnyEvent->one_event while !$_[0]{_ae_sent};	1559	AnyEvent->one_event while !$_[0]{_ae_sent};
1152	}	1560	}
1153		1561
1154	sub recv {	1562	sub recv {
1155	$_[0]->_wait;	1563	$_[0]->_wait;
…		…
1196	so on.	1604	so on.
1197		1605
1198	=head1 ENVIRONMENT VARIABLES	1606	=head1 ENVIRONMENT VARIABLES
1199		1607
1200	The following environment variables are used by this module or its	1608	The following environment variables are used by this module or its
1201	submodules:	1609	submodules.
		1610
		1611	Note that AnyEvent will remove I<all> environment variables starting with
		1612	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1613	enabled.
1202		1614
1203	=over 4	1615	=over 4
1204		1616
1205	=item C<PERL_ANYEVENT_VERBOSE>	1617	=item C<PERL_ANYEVENT_VERBOSE>
1206		1618
…		…
1213	C<PERL_ANYEVENT_MODEL>.	1625	C<PERL_ANYEVENT_MODEL>.
1214		1626
1215	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1627	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1216	model it chooses.	1628	model it chooses.
1217		1629
		1630	When set to C<8> or higher, then AnyEvent will report extra information on
		1631	which optional modules it loads and how it implements certain features.
		1632
1218	=item C<PERL_ANYEVENT_STRICT>	1633	=item C<PERL_ANYEVENT_STRICT>
1219		1634
1220	AnyEvent does not do much argument checking by default, as thorough	1635	AnyEvent does not do much argument checking by default, as thorough
1221	argument checking is very costly. Setting this variable to a true value	1636	argument checking is very costly. Setting this variable to a true value
1222	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1637	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1223	check the arguments passed to most method calls. If it finds any problems	1638	check the arguments passed to most method calls. If it finds any problems,
1224	it will croak.	1639	it will croak.
1225		1640
1226	In other words, enables "strict" mode.	1641	In other words, enables "strict" mode.
1227		1642
1228	Unlike C<use strict>, it is definitely recommended ot keep it off in	1643	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1229	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1644	>>, it is definitely recommended to keep it off in production. Keeping
1230	developing programs can be very useful, however.	1645	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1646	can be very useful, however.
1231		1647
1232	=item C<PERL_ANYEVENT_MODEL>	1648	=item C<PERL_ANYEVENT_MODEL>
1233		1649
1234	This can be used to specify the event model to be used by AnyEvent, before	1650	This can be used to specify the event model to be used by AnyEvent, before
1235	auto detection and -probing kicks in. It must be a string consisting	1651	auto detection and -probing kicks in. It must be a string consisting
…		…
1256	used, and preference will be given to protocols mentioned earlier in the	1672	used, and preference will be given to protocols mentioned earlier in the
1257	list.	1673	list.
1258		1674
1259	This variable can effectively be used for denial-of-service attacks	1675	This variable can effectively be used for denial-of-service attacks
1260	against local programs (e.g. when setuid), although the impact is likely	1676	against local programs (e.g. when setuid), although the impact is likely
1261	small, as the program has to handle connection errors already-	1677	small, as the program has to handle conenction and other failures anyways.
1262		1678
1263	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,	1679	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1264	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>	1680	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1265	- only support IPv4, never try to resolve or contact IPv6	1681	- only support IPv4, never try to resolve or contact IPv6
1266	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or	1682	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
…		…
1278		1694
1279	=item C<PERL_ANYEVENT_MAX_FORKS>	1695	=item C<PERL_ANYEVENT_MAX_FORKS>
1280		1696
1281	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1697	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1282	will create in parallel.	1698	will create in parallel.
		1699
		1700	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1701
		1702	The default value for the C<max_outstanding> parameter for the default DNS
		1703	resolver - this is the maximum number of parallel DNS requests that are
		1704	sent to the DNS server.
		1705
		1706	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1707
		1708	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1709	configuration) in the default resolver. When set to the empty string, no
		1710	default config will be used.
		1711
		1712	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1713
		1714	When neither C<ca_file> nor C<ca_path> was specified during
		1715	L<AnyEvent::TLS> context creation, and either of these environment
		1716	variables exist, they will be used to specify CA certificate locations
		1717	instead of a system-dependent default.
		1718
		1719	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1720
		1721	When these are set to C<1>, then the respective modules are not
		1722	loaded. Mostly good for testing AnyEvent itself.
1283		1723
1284	=back	1724	=back
1285		1725
1286	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1726	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1287		1727
…		…
1526	watcher.	1966	watcher.
1527		1967
1528	=head3 Results	1968	=head3 Results
1529		1969
1530	name watchers bytes create invoke destroy comment	1970	name watchers bytes create invoke destroy comment
1531	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1971	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1532	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1972	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1533	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1973	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1534	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1974	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1535	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1975	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1536	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	1976	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		1977	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		1978	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1537	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1979	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1538	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1980	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1539	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1981	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1540	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1982	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1541		1983
1542	=head3 Discussion	1984	=head3 Discussion
1543		1985
1544	The benchmark does I<not> measure scalability of the event loop very	1986	The benchmark does I<not> measure scalability of the event loop very
1545	well. For example, a select-based event loop (such as the pure perl one)	1987	well. For example, a select-based event loop (such as the pure perl one)
…		…
1570	performance becomes really bad with lots of file descriptors (and few of	2012	performance becomes really bad with lots of file descriptors (and few of
1571	them active), of course, but this was not subject of this benchmark.	2013	them active), of course, but this was not subject of this benchmark.
1572		2014
1573	The C<Event> module has a relatively high setup and callback invocation	2015	The C<Event> module has a relatively high setup and callback invocation
1574	cost, but overall scores in on the third place.	2016	cost, but overall scores in on the third place.
		2017
		2018	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2019	when using its pure perl backend.
1575		2020
1576	C<Glib>'s memory usage is quite a bit higher, but it features a	2021	C<Glib>'s memory usage is quite a bit higher, but it features a
1577	faster callback invocation and overall ends up in the same class as	2022	faster callback invocation and overall ends up in the same class as
1578	C<Event>. However, Glib scales extremely badly, doubling the number of	2023	C<Event>. However, Glib scales extremely badly, doubling the number of
1579	watchers increases the processing time by more than a factor of four,	2024	watchers increases the processing time by more than a factor of four,
…		…
1657	it to another server. This includes deleting the old timeout and creating	2102	it to another server. This includes deleting the old timeout and creating
1658	a new one that moves the timeout into the future.	2103	a new one that moves the timeout into the future.
1659		2104
1660	=head3 Results	2105	=head3 Results
1661		2106
1662	name sockets create request	2107	name sockets create request
1663	EV 20000 69.01 11.16	2108	EV 20000 69.01 11.16
1664	Perl 20000 73.32 35.87	2109	Perl 20000 73.32 35.87
		2110	IOAsync 20000 157.00 98.14 epoll
		2111	IOAsync 20000 159.31 616.06 poll
1665	Event 20000 212.62 257.32	2112	Event 20000 212.62 257.32
1666	Glib 20000 651.16 1896.30	2113	Glib 20000 651.16 1896.30
1667	POE 20000 349.67 12317.24 uses POE::Loop::Event	2114	POE 20000 349.67 12317.24 uses POE::Loop::Event
1668		2115
1669	=head3 Discussion	2116	=head3 Discussion
1670		2117
1671	This benchmark I<does> measure scalability and overall performance of the	2118	This benchmark I<does> measure scalability and overall performance of the
1672	particular event loop.	2119	particular event loop.
…		…
1674	EV is again fastest. Since it is using epoll on my system, the setup time	2121	EV is again fastest. Since it is using epoll on my system, the setup time
1675	is relatively high, though.	2122	is relatively high, though.
1676		2123
1677	Perl surprisingly comes second. It is much faster than the C-based event	2124	Perl surprisingly comes second. It is much faster than the C-based event
1678	loops Event and Glib.	2125	loops Event and Glib.
		2126
		2127	IO::Async performs very well when using its epoll backend, and still quite
		2128	good compared to Glib when using its pure perl backend.
1679		2129
1680	Event suffers from high setup time as well (look at its code and you will	2130	Event suffers from high setup time as well (look at its code and you will
1681	understand why). Callback invocation also has a high overhead compared to	2131	understand why). Callback invocation also has a high overhead compared to
1682	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2132	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1683	uses select or poll in basically all documented configurations.	2133	uses select or poll in basically all documented configurations.
…		…
1746	=item * C-based event loops perform very well with small number of	2196	=item * C-based event loops perform very well with small number of
1747	watchers, as the management overhead dominates.	2197	watchers, as the management overhead dominates.
1748		2198
1749	=back	2199	=back
1750		2200
		2201	=head2 THE IO::Lambda BENCHMARK
		2202
		2203	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2204	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2205	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2206	shouldn't come as a surprise to anybody). As such, the benchmark is
		2207	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2208	very optimal. But how would AnyEvent compare when used without the extra
		2209	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2210
		2211	The benchmark itself creates an echo-server, and then, for 500 times,
		2212	connects to the echo server, sends a line, waits for the reply, and then
		2213	creates the next connection. This is a rather bad benchmark, as it doesn't
		2214	test the efficiency of the framework or much non-blocking I/O, but it is a
		2215	benchmark nevertheless.
		2216
		2217	name runtime
		2218	Lambda/select 0.330 sec
		2219	+ optimized 0.122 sec
		2220	Lambda/AnyEvent 0.327 sec
		2221	+ optimized 0.138 sec
		2222	Raw sockets/select 0.077 sec
		2223	POE/select, components 0.662 sec
		2224	POE/select, raw sockets 0.226 sec
		2225	POE/select, optimized 0.404 sec
		2226
		2227	AnyEvent/select/nb 0.085 sec
		2228	AnyEvent/EV/nb 0.068 sec
		2229	+state machine 0.134 sec
		2230
		2231	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2232	benchmarks actually make blocking connects and use 100% blocking I/O,
		2233	defeating the purpose of an event-based solution. All of the newly
		2234	written AnyEvent benchmarks use 100% non-blocking connects (using
		2235	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2236	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2237	generally require a lot more bookkeeping and event handling than blocking
		2238	connects (which involve a single syscall only).
		2239
		2240	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2241	offers similar expressive power as POE and IO::Lambda, using conventional
		2242	Perl syntax. This means that both the echo server and the client are 100%
		2243	non-blocking, further placing it at a disadvantage.
		2244
		2245	As you can see, the AnyEvent + EV combination even beats the
		2246	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2247	backend easily beats IO::Lambda and POE.
		2248
		2249	And even the 100% non-blocking version written using the high-level (and
		2250	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2251	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2252	in a non-blocking way.
		2253
		2254	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2255	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2256	part of the IO::lambda distribution and were used without any changes.
		2257
		2258
		2259	=head1 SIGNALS
		2260
		2261	AnyEvent currently installs handlers for these signals:
		2262
		2263	=over 4
		2264
		2265	=item SIGCHLD
		2266
		2267	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		2268	emulation for event loops that do not support them natively. Also, some
		2269	event loops install a similar handler.
		2270
		2271	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2272	AnyEvent will reset it to default, to avoid losing child exit statuses.
		2273
		2274	=item SIGPIPE
		2275
		2276	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		2277	when AnyEvent gets loaded.
		2278
		2279	The rationale for this is that AnyEvent users usually do not really depend
		2280	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		2281	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		2282	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		2283	some random socket.
		2284
		2285	The rationale for installing a no-op handler as opposed to ignoring it is
		2286	that this way, the handler will be restored to defaults on exec.
		2287
		2288	Feel free to install your own handler, or reset it to defaults.
		2289
		2290	=back
		2291
		2292	=cut
		2293
		2294	undef $SIG{CHLD}
		2295	if $SIG{CHLD} eq 'IGNORE';
		2296
		2297	$SIG{PIPE} = sub { }
		2298	unless defined $SIG{PIPE};
		2299
		2300	=head1 RECOMMENDED/OPTIONAL MODULES
		2301
		2302	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2303	it's built-in modules) are required to use it.
		2304
		2305	That does not mean that AnyEvent won't take advantage of some additional
		2306	modules if they are installed.
		2307
		2308	This section epxlains which additional modules will be used, and how they
		2309	affect AnyEvent's operetion.
		2310
		2311	=over 4
		2312
		2313	=item L<Async::Interrupt>
		2314
		2315	This slightly arcane module is used to implement fast signal handling: To
		2316	my knowledge, there is no way to do completely race-free and quick
		2317	signal handling in pure perl. To ensure that signals still get
		2318	delivered, AnyEvent will start an interval timer to wake up perl (and
		2319	catch the signals) with some delay (default is 10 seconds, look for
		2320	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2321
		2322	If this module is available, then it will be used to implement signal
		2323	catching, which means that signals will not be delayed, and the event loop
		2324	will not be interrupted regularly, which is more efficient (And good for
		2325	battery life on laptops).
		2326
		2327	This affects not just the pure-perl event loop, but also other event loops
		2328	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2329
		2330	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2331	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2332	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2333	does nothing for those backends.
		2334
		2335	=item L<EV>
		2336
		2337	This module isn't really "optional", as it is simply one of the backend
		2338	event loops that AnyEvent can use. However, it is simply the best event
		2339	loop available in terms of features, speed and stability: It supports
		2340	the AnyEvent API optimally, implements all the watcher types in XS, does
		2341	automatic timer adjustments even when no monotonic clock is available,
		2342	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2343	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2344	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2345
		2346	=item L<Guard>
		2347
		2348	The guard module, when used, will be used to implement
		2349	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2350	lot less memory), but otherwise doesn't affect guard operation much. It is
		2351	purely used for performance.
		2352
		2353	=item L<JSON> and L<JSON::XS>
		2354
		2355	This module is required when you want to read or write JSON data via
		2356	L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2357	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2358
		2359	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2360	installed.
		2361
		2362	=item L<Net::SSLeay>
		2363
		2364	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2365	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2366	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2367
		2368	=item L<Time::HiRes>
		2369
		2370	This module is part of perl since release 5.008. It will be used when the
		2371	chosen event library does not come with a timing source on it's own. The
		2372	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2373	try to use a monotonic clock for timing stability.
		2374
		2375	=back
		2376
1751		2377
1752	=head1 FORK	2378	=head1 FORK
1753		2379
1754	Most event libraries are not fork-safe. The ones who are usually are	2380	Most event libraries are not fork-safe. The ones who are usually are
1755	because they rely on inefficient but fork-safe C<select> or C<poll>	2381	because they rely on inefficient but fork-safe C<select> or C<poll>
1756	calls. Only L<EV> is fully fork-aware.	2382	calls. Only L<EV> is fully fork-aware.
1757		2383
1758	If you have to fork, you must either do so I<before> creating your first	2384	If you have to fork, you must either do so I<before> creating your first
1759	watcher OR you must not use AnyEvent at all in the child.	2385	watcher OR you must not use AnyEvent at all in the child OR you must do
		2386	something completely out of the scope of AnyEvent.
1760		2387
1761		2388
1762	=head1 SECURITY CONSIDERATIONS	2389	=head1 SECURITY CONSIDERATIONS
1763		2390
1764	AnyEvent can be forced to load any event model via	2391	AnyEvent can be forced to load any event model via
…		…
1776	use AnyEvent;	2403	use AnyEvent;
1777		2404
1778	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2405	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1779	be used to probe what backend is used and gain other information (which is	2406	be used to probe what backend is used and gain other information (which is
1780	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2407	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1781	$ENV{PERL_ANYEGENT_STRICT}.	2408	$ENV{PERL_ANYEVENT_STRICT}.
		2409
		2410	Note that AnyEvent will remove I<all> environment variables starting with
		2411	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2412	enabled.
1782		2413
1783		2414
1784	=head1 BUGS	2415	=head1 BUGS
1785		2416
1786	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2417	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1787	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2418	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1788	and check wether the leaks still show up. (Perl 5.10.0 has other annoying	2419	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1789	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as	2420	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1790	pronounced).	2421	pronounced).
1791		2422
1792		2423
1793	=head1 SEE ALSO	2424	=head1 SEE ALSO
1794		2425
…		…
1798	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2429	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1799		2430
1800	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2431	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1801	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2432	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1802	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2433	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1803	L<AnyEvent::Impl::POE>.	2434	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1804		2435
1805	Non-blocking file handles, sockets, TCP clients and	2436	Non-blocking file handles, sockets, TCP clients and
1806	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2437	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1807		2438
1808	Asynchronous DNS: L<AnyEvent::DNS>.	2439	Asynchronous DNS: L<AnyEvent::DNS>.
1809		2440
1810	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2441	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2442	L<Coro::Event>,
1811		2443
1812	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2444	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2445	L<AnyEvent::HTTP>.
1813		2446
1814		2447
1815	=head1 AUTHOR	2448	=head1 AUTHOR
1816		2449
1817	Marc Lehmann <schmorp@schmorp.de>	2450	Marc Lehmann <schmorp@schmorp.de>

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