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Revision 1.190 by root, Wed Nov 5 02:21:27 2008 UTC vs.
Revision 1.329 by root, Sun Jul 11 05:44:22 2010 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, 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	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
		15	# file handle or descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
12		17
		18	# one-shot or repeating timers
13	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
14	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
15		21
16	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
17	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
18		24
		25	# POSIX signal
19	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });	26	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
20		27
		28	# child process exit
21	my $w = AnyEvent->child (pid => $pid, cb => sub {	29	my $w = AnyEvent->child (pid => $pid, cb => sub {
22	my ($pid, $status) = @_;	30	my ($pid, $status) = @_;
23	...	31	...
24	});	32	});
		33
		34	# called when event loop idle (if applicable)
		35	my $w = AnyEvent->idle (cb => sub { ... });
25		36
26	my $w = AnyEvent->condvar; # stores whether a condition was flagged	37	my $w = AnyEvent->condvar; # stores whether a condition was flagged
27	$w->send; # wake up current and all future recv's	38	$w->send; # wake up current and all future recv's
28	$w->recv; # enters "main loop" till $condvar gets ->send	39	$w->recv; # enters "main loop" till $condvar gets ->send
29	# use a condvar in callback mode:	40	# use a condvar in callback mode:
…		…
32	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
33		44
34	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
35	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
36	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
		48
		49	=head1 SUPPORT
		50
		51	There is a mailinglist for discussing all things AnyEvent, and an IRC
		52	channel, too.
		53
		54	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		55	Repository>, at L<http://anyevent.schmorp.de>, for more info.
37		56
38	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	57	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
39		58
40	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	59	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
41	nowadays. So what is different about AnyEvent?	60	nowadays. So what is different about AnyEvent?
…		…
119	use AnyEvent;	138	use AnyEvent;
120		139
121	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
122		141
123	The I<likely> means that, if any module loads another event model and	142	The I<likely> means that, if any module loads another event model and
124	starts using it, all bets are off. Maybe you should tell their authors to	143	starts using it, all bets are off - this case should be very rare though,
125	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
126		146
127	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called
128	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	148	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
129	explicitly and enjoy the high availability of that event loop :)	149	explicitly and enjoy the high availability of that event loop :)
130		150
…		…
137	These watchers are normal Perl objects with normal Perl lifetime. After	157	These watchers are normal Perl objects with normal Perl lifetime. After
138	creating a watcher it will immediately "watch" for events and invoke the	158	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	159	callback when the event occurs (of course, only when the event model
140	is in control).	160	is in control).
141		161
		162	Note that B<callbacks must not permanently change global variables>
		163	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
		164	callbacks must not C<die> >>. The former is good programming practise in
		165	Perl and the latter stems from the fact that exception handling differs
		166	widely between event loops.
		167
142	To disable the watcher you have to destroy it (e.g. by setting the	168	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	169	variable you store it in to C<undef> or otherwise deleting all references
144	to it).	170	to it).
145		171
146	All watchers are created by calling a method on the C<AnyEvent> class.	172	All watchers are created by calling a method on the C<AnyEvent> class.
…		…
159	my variables are only visible after the statement in which they are	185	my variables are only visible after the statement in which they are
160	declared.	186	declared.
161		187
162	=head2 I/O WATCHERS	188	=head2 I/O WATCHERS
163		189
		190	$w = AnyEvent->io (
		191	fh => <filehandle_or_fileno>,
		192	poll => <"r" or "w">,
		193	cb => <callback>,
		194	);
		195
164	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	196	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
165	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
166		198
167	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events	199	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>	200	for events (AnyEvent might or might not keep a reference to this file
		201	handle). Note that only file handles pointing to things for which
		202	non-blocking operation makes sense are allowed. This includes sockets,
		203	most character devices, pipes, fifos and so on, but not for example files
		204	or block devices.
		205
169	must be a string that is either C<r> or C<w>, which creates a watcher	206	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	207	watcher waiting for "r"eadable or "w"ritable events, respectively.
		208
171	callback to invoke each time the file handle becomes ready.	209	C<cb> is the callback to invoke each time the file handle becomes ready.
172		210
173	Although the callback might get passed parameters, their value and	211	Although the callback might get passed parameters, their value and
174	presence is undefined and you cannot rely on them. Portable AnyEvent	212	presence is undefined and you cannot rely on them. Portable AnyEvent
175	callbacks cannot use arguments passed to I/O watcher callbacks.	213	callbacks cannot use arguments passed to I/O watcher callbacks.
176		214
…		…
191	undef $w;	229	undef $w;
192	});	230	});
193		231
194	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
195		233
		234	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		235
		236	$w = AnyEvent->timer (
		237	after => <fractional_seconds>,
		238	interval => <fractional_seconds>,
		239	cb => <callback>,
		240	);
		241
196	You can create a time watcher by calling the C<< AnyEvent->timer >>	242	You can create a time watcher by calling the C<< AnyEvent->timer >>
197	method with the following mandatory arguments:	243	method with the following mandatory arguments:
198		244
199	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
200	supported) the callback should be invoked. C<cb> is the callback to invoke	246	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
308	In either case, if you care (and in most cases, you don't), then you	354	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	355	can get whatever behaviour you want with any event loop, by taking the
310	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	356	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
311	account.	357	account.
312		358
		359	=item AnyEvent->now_update
		360
		361	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		362	the current time for each loop iteration (see the discussion of L<<
		363	AnyEvent->now >>, above).
		364
		365	When a callback runs for a long time (or when the process sleeps), then
		366	this "current" time will differ substantially from the real time, which
		367	might affect timers and time-outs.
		368
		369	When this is the case, you can call this method, which will update the
		370	event loop's idea of "current time".
		371
		372	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		373	when mod_perl executes the script, then the event loop will have the wrong
		374	idea about the "current time" (being potentially far in the past, when the
		375	script ran the last time). In that case you should arrange a call to C<<
		376	AnyEvent->now_update >> each time the web server process wakes up again
		377	(e.g. at the start of your script, or in a handler).
		378
		379	Note that updating the time I<might> cause some events to be handled.
		380
313	=back	381	=back
314		382
315	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
316		386
317	You can watch for signals using a signal watcher, C<signal> is the signal	387	You can watch for signals using a signal watcher, C<signal> is the signal
318	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	388	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
319	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
320		390
…		…
326	invocation, and callback invocation will be synchronous. Synchronous means	396	invocation, and callback invocation will be synchronous. Synchronous means
327	that it might take a while until the signal gets handled by the process,	397	that it might take a while until the signal gets handled by the process,
328	but it is guaranteed not to interrupt any other callbacks.	398	but it is guaranteed not to interrupt any other callbacks.
329		399
330	The main advantage of using these watchers is that you can share a signal	400	The main advantage of using these watchers is that you can share a signal
331	between multiple watchers.	401	between multiple watchers, and AnyEvent will ensure that signals will not
		402	interrupt your program at bad times.
332		403
333	This watcher might use C<%SIG>, so programs overwriting those signals	404	This watcher might use C<%SIG> (depending on the event loop used),
334	directly will likely not work correctly.	405	so programs overwriting those signals directly will likely not work
		406	correctly.
335		407
336	Example: exit on SIGINT	408	Example: exit on SIGINT
337		409
338	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
339		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling) or
		421	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		422	latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
		429	=head3 Signal Races, Delays and Workarounds
		430
		431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		432	callbacks to signals in a generic way, which is a pity, as you cannot
		433	do race-free signal handling in perl, requiring C libraries for
		434	this. AnyEvent will try to do it's best, which means in some cases,
		435	signals will be delayed. The maximum time a signal might be delayed is
		436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		437	variable can be changed only before the first signal watcher is created,
		438	and should be left alone otherwise. This variable determines how often
		439	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		440	will cause fewer spurious wake-ups, which is better for power and CPU
		441	saving.
		442
		443	All these problems can be avoided by installing the optional
		444	L<Async::Interrupt> module, which works with most event loops. It will not
		445	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		446	(and not with L<POE> currently, as POE does it's own workaround with
		447	one-second latency). For those, you just have to suffer the delays.
		448
340	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
341		450
		451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		452
342	You can also watch on a child process exit and catch its exit status.	453	You can also watch on a child process exit and catch its exit status.
343		454
344	The child process is specified by the C<pid> argument (if set to C<0>, it	455	The child process is specified by the C<pid> argument (one some backends,
345	watches for any child process exit). The watcher will triggered only when	456	using C<0> watches for any child process exit, on others this will
346	the child process has finished and an exit status is available, not on	457	croak). The watcher will be triggered only when the child process has
347	any trace events (stopped/continued).	458	finished and an exit status is available, not on any trace events
		459	(stopped/continued).
348		460
349	The callback will be called with the pid and exit status (as returned by	461	The callback will be called with the pid and exit status (as returned by
350	waitpid), so unlike other watcher types, you I<can> rely on child watcher	462	waitpid), so unlike other watcher types, you I<can> rely on child watcher
351	callback arguments.	463	callback arguments.
352		464
…		…
357		469
358	There is a slight catch to child watchers, however: you usually start them	470	There is a slight catch to child watchers, however: you usually start them
359	I<after> the child process was created, and this means the process could	471	I<after> the child process was created, and this means the process could
360	have exited already (and no SIGCHLD will be sent anymore).	472	have exited already (and no SIGCHLD will be sent anymore).
361		473
362	Not all event models handle this correctly (POE doesn't), but even for	474	Not all event models handle this correctly (neither POE nor IO::Async do,
		475	see their AnyEvent::Impl manpages for details), but even for event models
363	event models that I<do> handle this correctly, they usually need to be	476	that I<do> handle this correctly, they usually need to be loaded before
364	loaded before the process exits (i.e. before you fork in the first place).	477	the process exits (i.e. before you fork in the first place). AnyEvent's
		478	pure perl event loop handles all cases correctly regardless of when you
		479	start the watcher.
365		480
366	This means you cannot create a child watcher as the very first thing in an	481	This means you cannot create a child watcher as the very first
367	AnyEvent program, you I<have> to create at least one watcher before you	482	thing in an AnyEvent program, you I<have> to create at least one
368	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	483	watcher before you C<fork> the child (alternatively, you can call
		484	C<AnyEvent::detect>).
		485
		486	As most event loops do not support waiting for child events, they will be
		487	emulated by AnyEvent in most cases, in which the latency and race problems
		488	mentioned in the description of signal watchers apply.
369		489
370	Example: fork a process and wait for it	490	Example: fork a process and wait for it
371		491
372	my $done = AnyEvent->condvar;	492	my $done = AnyEvent->condvar;
373		493
…		…
383	);	503	);
384		504
385	# do something else, then wait for process exit	505	# do something else, then wait for process exit
386	$done->recv;	506	$done->recv;
387		507
		508	=head2 IDLE WATCHERS
		509
		510	$w = AnyEvent->idle (cb => <callback>);
		511
		512	Repeatedly invoke the callback after the process becomes idle, until
		513	either the watcher is destroyed or new events have been detected.
		514
		515	Idle watchers are useful when there is a need to do something, but it
		516	is not so important (or wise) to do it instantly. The callback will be
		517	invoked only when there is "nothing better to do", which is usually
		518	defined as "all outstanding events have been handled and no new events
		519	have been detected". That means that idle watchers ideally get invoked
		520	when the event loop has just polled for new events but none have been
		521	detected. Instead of blocking to wait for more events, the idle watchers
		522	will be invoked.
		523
		524	Unfortunately, most event loops do not really support idle watchers (only
		525	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		526	will simply call the callback "from time to time".
		527
		528	Example: read lines from STDIN, but only process them when the
		529	program is otherwise idle:
		530
		531	my @lines; # read data
		532	my $idle_w;
		533	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		534	push @lines, scalar <STDIN>;
		535
		536	# start an idle watcher, if not already done
		537	$idle_w ||= AnyEvent->idle (cb => sub {
		538	# handle only one line, when there are lines left
		539	if (my $line = shift @lines) {
		540	print "handled when idle: $line";
		541	} else {
		542	# otherwise disable the idle watcher again
		543	undef $idle_w;
		544	}
		545	});
		546	});
		547
388	=head2 CONDITION VARIABLES	548	=head2 CONDITION VARIABLES
		549
		550	$cv = AnyEvent->condvar;
		551
		552	$cv->send (<list>);
		553	my @res = $cv->recv;
389		554
390	If you are familiar with some event loops you will know that all of them	555	If you are familiar with some event loops you will know that all of them
391	require you to run some blocking "loop", "run" or similar function that	556	require you to run some blocking "loop", "run" or similar function that
392	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
393		558
394	AnyEvent is different, it expects somebody else to run the event loop and	559	AnyEvent is slightly different: it expects somebody else to run the event
395	will only block when necessary (usually when told by the user).	560	loop and will only block when necessary (usually when told by the user).
396		561
397	The instrument to do that is called a "condition variable", so called	562	The tool to do that is called a "condition variable", so called because
398	because they represent a condition that must become true.	563	they represent a condition that must become true.
		564
		565	Now is probably a good time to look at the examples further below.
399		566
400	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
401	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
402
403	C<cb>, which specifies a callback to be called when the condition variable	569	C<cb>, which specifies a callback to be called when the condition variable
404	becomes true, with the condition variable as the first argument (but not	570	becomes true, with the condition variable as the first argument (but not
405	the results).	571	the results).
406		572
407	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
408	by calling the C<send> method (or calling the condition variable as if it	574	by calling the C<send> method (or calling the condition variable as if it
409	were a callback, read about the caveats in the description for the C<<	575	were a callback, read about the caveats in the description for the C<<
410	->send >> method).	576	->send >> method).
411		577
412	Condition variables are similar to callbacks, except that you can	578	Since condition variables are the most complex part of the AnyEvent API, here are
413	optionally wait for them. They can also be called merge points - points	579	some different mental models of what they are - pick the ones you can connect to:
414	in time where multiple outstanding events have been processed. And yet	580
415	another way to call them is transactions - each condition variable can be	581	=over 4
416	used to represent a transaction, which finishes at some point and delivers	582
417	a result.	583	=item * Condition variables are like callbacks - you can call them (and pass them instead
		584	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		585
		586	=item * Condition variables are signals - one side can emit or send them,
		587	the other side can wait for them, or install a handler that is called when
		588	the signal fires.
		589
		590	=item * Condition variables are like "Merge Points" - points in your program
		591	where you merge multiple independent results/control flows into one.
		592
		593	=item * Condition variables represent a transaction - function that start
		594	some kind of transaction can return them, leaving the caller the choice
		595	between waiting in a blocking fashion, or setting a callback.
		596
		597	=item * Condition variables represent future values, or promises to deliver
		598	some result, long before the result is available.
		599
		600	=back
418		601
419	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
420	for example, if you write a module that does asynchronous http requests,	603	for example, if you write a module that does asynchronous http requests,
421	then a condition variable would be the ideal candidate to signal the	604	then a condition variable would be the ideal candidate to signal the
422	availability of results. The user can either act when the callback is	605	availability of results. The user can either act when the callback is
…		…
443	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
444	for the send to occur.	627	for the send to occur.
445		628
446	Example: wait for a timer.	629	Example: wait for a timer.
447		630
448	# wait till the result is ready	631	# condition: "wait till the timer is fired"
449	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
450		633
451	# do something such as adding a timer	634	# create the timer - we could wait for, say
452	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
453	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
454	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
455	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
456	after => 1,	639	after => 1,
457	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
458	);	641	);
459		642
460	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
461	# calls send	644	# calls ->send
462	$result_ready->recv;	645	$timer_fired->recv;
463		646
464	Example: wait for a timer, but take advantage of the fact that	647	Example: wait for a timer, but take advantage of the fact that condition
465	condition variables are also code references.	648	variables are also callable directly.
466		649
467	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
468	my $delay = AnyEvent->timer (after => 5, cb => $done);	651	my $delay = AnyEvent->timer (after => 5, cb => $done);
469	$done->recv;	652	$done->recv;
470		653
…		…
476		659
477	...	660	...
478		661
479	my @info = $couchdb->info->recv;	662	my @info = $couchdb->info->recv;
480		663
481	And this is how you would just ste a callback to be called whenever the	664	And this is how you would just set a callback to be called whenever the
482	results are available:	665	results are available:
483		666
484	$couchdb->info->cb (sub {	667	$couchdb->info->cb (sub {
485	my @info = $_[0]->recv;	668	my @info = $_[0]->recv;
486	});	669	});
…		…
504	immediately from within send.	687	immediately from within send.
505		688
506	Any arguments passed to the C<send> call will be returned by all	689	Any arguments passed to the C<send> call will be returned by all
507	future C<< ->recv >> calls.	690	future C<< ->recv >> calls.
508		691
509	Condition variables are overloaded so one can call them directly	692	Condition variables are overloaded so one can call them directly (as if
510	(as a code reference). Calling them directly is the same as calling	693	they were a code reference). Calling them directly is the same as calling
511	C<send>. Note, however, that many C-based event loops do not handle	694	C<send>.
512	overloading, so as tempting as it may be, passing a condition variable
513	instead of a callback does not work. Both the pure perl and EV loops
514	support overloading, however, as well as all functions that use perl to
515	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
516	example).
517		695
518	=item $cv->croak ($error)	696	=item $cv->croak ($error)
519		697
520	Similar to send, but causes all call's to C<< ->recv >> to invoke	698	Similar to send, but causes all call's to C<< ->recv >> to invoke
521	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
522		700
523	This can be used to signal any errors to the condition variable	701	This can be used to signal any errors to the condition variable
524	user/consumer.	702	user/consumer. Doing it this way instead of calling C<croak> directly
		703	delays the error detetcion, but has the overwhelmign advantage that it
		704	diagnoses the error at the place where the result is expected, and not
		705	deep in some event clalback without connection to the actual code causing
		706	the problem.
525		707
526	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
527		709
528	=item $cv->end	710	=item $cv->end
529
530	These two methods are EXPERIMENTAL and MIGHT CHANGE.
531		711
532	These two methods can be used to combine many transactions/events into	712	These two methods can be used to combine many transactions/events into
533	one. For example, a function that pings many hosts in parallel might want	713	one. For example, a function that pings many hosts in parallel might want
534	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
535		715
536	Every call to C<< ->begin >> will increment a counter, and every call to	716	Every call to C<< ->begin >> will increment a counter, and every call to
537	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	717	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
538	>>, the (last) callback passed to C<begin> will be executed. That callback	718	>>, the (last) callback passed to C<begin> will be executed, passing the
539	is I<supposed> to call C<< ->send >>, but that is not required. If no	719	condvar as first argument. That callback is I<supposed> to call C<< ->send
540	callback was set, C<send> will be called without any arguments.	720	>>, but that is not required. If no group callback was set, C<send> will
		721	be called without any arguments.
541		722
542	Let's clarify this with the ping example:	723	You can think of C<< $cv->send >> giving you an OR condition (one call
		724	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		725	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		726
		727	Let's start with a simple example: you have two I/O watchers (for example,
		728	STDOUT and STDERR for a program), and you want to wait for both streams to
		729	close before activating a condvar:
543		730
544	my $cv = AnyEvent->condvar;	731	my $cv = AnyEvent->condvar;
545		732
		733	$cv->begin; # first watcher
		734	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		735	defined sysread $fh1, my $buf, 4096
		736	or $cv->end;
		737	});
		738
		739	$cv->begin; # second watcher
		740	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		741	defined sysread $fh2, my $buf, 4096
		742	or $cv->end;
		743	});
		744
		745	$cv->recv;
		746
		747	This works because for every event source (EOF on file handle), there is
		748	one call to C<begin>, so the condvar waits for all calls to C<end> before
		749	sending.
		750
		751	The ping example mentioned above is slightly more complicated, as the
		752	there are results to be passwd back, and the number of tasks that are
		753	begung can potentially be zero:
		754
		755	my $cv = AnyEvent->condvar;
		756
546	my %result;	757	my %result;
547	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
548		759
549	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
550	$cv->begin;	761	$cv->begin;
551	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
552	$result{$host} = ...;	763	$result{$host} = ...;
…		…
567	loop, which serves two important purposes: first, it sets the callback	778	loop, which serves two important purposes: first, it sets the callback
568	to be called once the counter reaches C<0>, and second, it ensures that	779	to be called once the counter reaches C<0>, and second, it ensures that
569	C<send> is called even when C<no> hosts are being pinged (the loop	780	C<send> is called even when C<no> hosts are being pinged (the loop
570	doesn't execute once).	781	doesn't execute once).
571		782
572	This is the general pattern when you "fan out" into multiple subrequests:	783	This is the general pattern when you "fan out" into multiple (but
573	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	784	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
574	is called at least once, and then, for each subrequest you start, call	785	the callback and ensure C<end> is called at least once, and then, for each
575	C<begin> and for each subrequest you finish, call C<end>.	786	subrequest you start, call C<begin> and for each subrequest you finish,
		787	call C<end>.
576		788
577	=back	789	=back
578		790
579	=head3 METHODS FOR CONSUMERS	791	=head3 METHODS FOR CONSUMERS
580		792
…		…
596	function will call C<croak>.	808	function will call C<croak>.
597		809
598	In list context, all parameters passed to C<send> will be returned,	810	In list context, all parameters passed to C<send> will be returned,
599	in scalar context only the first one will be returned.	811	in scalar context only the first one will be returned.
600		812
		813	Note that doing a blocking wait in a callback is not supported by any
		814	event loop, that is, recursive invocation of a blocking C<< ->recv
		815	>> is not allowed, and the C<recv> call will C<croak> if such a
		816	condition is detected. This condition can be slightly loosened by using
		817	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		818	any thread that doesn't run the event loop itself.
		819
601	Not all event models support a blocking wait - some die in that case	820	Not all event models support a blocking wait - some die in that case
602	(programs might want to do that to stay interactive), so I<if you are	821	(programs might want to do that to stay interactive), so I<if you are
603	using this from a module, never require a blocking wait>, but let the	822	using this from a module, never require a blocking wait>. Instead, let the
604	caller decide whether the call will block or not (for example, by coupling	823	caller decide whether the call will block or not (for example, by coupling
605	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
606	callbacks so the caller knows that getting the result will not block,	825	callbacks so the caller knows that getting the result will not block,
607	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
608		827
609	Another reason I<never> to C<< ->recv >> in a module is that you cannot
610	sensibly have two C<< ->recv >>'s in parallel, as that would require
611	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
612	can supply.
613
614	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
615	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
616	versions and also integrates coroutines into AnyEvent, making blocking
617	C<< ->recv >> calls perfectly safe as long as they are done from another
618	coroutine (one that doesn't run the event loop).
619
620	You can ensure that C<< -recv >> never blocks by setting a callback and	828	You can ensure that C<< -recv >> never blocks by setting a callback and
621	only calling C<< ->recv >> from within that callback (or at a later	829	only calling C<< ->recv >> from within that callback (or at a later
622	time). This will work even when the event loop does not support blocking	830	time). This will work even when the event loop does not support blocking
623	waits otherwise.	831	waits otherwise.
624		832
…		…
630	=item $cb = $cv->cb ($cb->($cv))	838	=item $cb = $cv->cb ($cb->($cv))
631		839
632	This is a mutator function that returns the callback set and optionally	840	This is a mutator function that returns the callback set and optionally
633	replaces it before doing so.	841	replaces it before doing so.
634		842
635	The callback will be called when the condition becomes "true", i.e. when	843	The callback will be called when the condition becomes (or already was)
636	C<send> or C<croak> are called, with the only argument being the condition	844	"true", i.e. when C<send> or C<croak> are called (or were called), with
637	variable itself. Calling C<recv> inside the callback or at any later time	845	the only argument being the condition variable itself. Calling C<recv>
638	is guaranteed not to block.	846	inside the callback or at any later time is guaranteed not to block.
639		847
640	=back	848	=back
641		849
		850	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		851
		852	The available backend classes are (every class has its own manpage):
		853
		854	=over 4
		855
		856	=item Backends that are autoprobed when no other event loop can be found.
		857
		858	EV is the preferred backend when no other event loop seems to be in
		859	use. If EV is not installed, then AnyEvent will fall back to its own
		860	pure-perl implementation, which is available everywhere as it comes with
		861	AnyEvent itself.
		862
		863	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		864	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		865
		866	=item Backends that are transparently being picked up when they are used.
		867
		868	These will be used when they are currently loaded when the first watcher
		869	is created, in which case it is assumed that the application is using
		870	them. This means that AnyEvent will automatically pick the right backend
		871	when the main program loads an event module before anything starts to
		872	create watchers. Nothing special needs to be done by the main program.
		873
		874	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		875	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		876	AnyEvent::Impl::Tk based on Tk, very broken.
		877	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		878	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		879	AnyEvent::Impl::Irssi used when running within irssi.
		880
		881	=item Backends with special needs.
		882
		883	Qt requires the Qt::Application to be instantiated first, but will
		884	otherwise be picked up automatically. As long as the main program
		885	instantiates the application before any AnyEvent watchers are created,
		886	everything should just work.
		887
		888	AnyEvent::Impl::Qt based on Qt.
		889
		890	Support for IO::Async can only be partial, as it is too broken and
		891	architecturally limited to even support the AnyEvent API. It also
		892	is the only event loop that needs the loop to be set explicitly, so
		893	it can only be used by a main program knowing about AnyEvent. See
		894	L<AnyEvent::Impl::Async> for the gory details.
		895
		896	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		897
		898	=item Event loops that are indirectly supported via other backends.
		899
		900	Some event loops can be supported via other modules:
		901
		902	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		903
		904	B<WxWidgets> has no support for watching file handles. However, you can
		905	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		906	polls 20 times per second, which was considered to be too horrible to even
		907	consider for AnyEvent.
		908
		909	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		910	backend, so it can be supported through POE.
		911
		912	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		913	load L<POE> when detecting them, in the hope that POE will pick them up,
		914	in which case everything will be automatic.
		915
		916	=back
		917
642	=head1 GLOBAL VARIABLES AND FUNCTIONS	918	=head1 GLOBAL VARIABLES AND FUNCTIONS
643		919
		920	These are not normally required to use AnyEvent, but can be useful to
		921	write AnyEvent extension modules.
		922
644	=over 4	923	=over 4
645		924
646	=item $AnyEvent::MODEL	925	=item $AnyEvent::MODEL
647		926
648	Contains C<undef> until the first watcher is being created. Then it	927	Contains C<undef> until the first watcher is being created, before the
		928	backend has been autodetected.
		929
649	contains the event model that is being used, which is the name of the	930	Afterwards it contains the event model that is being used, which is the
650	Perl class implementing the model. This class is usually one of the	931	name of the Perl class implementing the model. This class is usually one
651	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	932	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
652	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	933	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
653		934	will be C<urxvt::anyevent>).
654	The known classes so far are:
655
656	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
657	AnyEvent::Impl::Event based on Event, second best choice.
658	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
659	AnyEvent::Impl::Glib based on Glib, third-best choice.
660	AnyEvent::Impl::Tk based on Tk, very bad choice.
661	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
662	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
663	AnyEvent::Impl::POE based on POE, not generic enough for full support.
664
665	There is no support for WxWidgets, as WxWidgets has no support for
666	watching file handles. However, you can use WxWidgets through the
667	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
668	second, which was considered to be too horrible to even consider for
669	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
670	it's adaptor.
671
672	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
673	autodetecting them.
674		935
675	=item AnyEvent::detect	936	=item AnyEvent::detect
676		937
677	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	938	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
678	if necessary. You should only call this function right before you would	939	if necessary. You should only call this function right before you would
679	have created an AnyEvent watcher anyway, that is, as late as possible at	940	have created an AnyEvent watcher anyway, that is, as late as possible at
680	runtime.	941	runtime, and not e.g. while initialising of your module.
		942
		943	If you need to do some initialisation before AnyEvent watchers are
		944	created, use C<post_detect>.
681		945
682	=item $guard = AnyEvent::post_detect { BLOCK }	946	=item $guard = AnyEvent::post_detect { BLOCK }
683		947
684	Arranges for the code block to be executed as soon as the event model is	948	Arranges for the code block to be executed as soon as the event model is
685	autodetected (or immediately if this has already happened).	949	autodetected (or immediately if this has already happened).
686		950
		951	The block will be executed I<after> the actual backend has been detected
		952	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		953	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		954	other initialisations - see the sources of L<AnyEvent::Strict> or
		955	L<AnyEvent::AIO> to see how this is used.
		956
		957	The most common usage is to create some global watchers, without forcing
		958	event module detection too early, for example, L<AnyEvent::AIO> creates
		959	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		960	avoid autodetecting the event module at load time.
		961
687	If called in scalar or list context, then it creates and returns an object	962	If called in scalar or list context, then it creates and returns an object
688	that automatically removes the callback again when it is destroyed. See	963	that automatically removes the callback again when it is destroyed (or
		964	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
689	L<Coro::BDB> for a case where this is useful.	965	a case where this is useful.
		966
		967	Example: Create a watcher for the IO::AIO module and store it in
		968	C<$WATCHER>. Only do so after the event loop is initialised, though.
		969
		970	our WATCHER;
		971
		972	my $guard = AnyEvent::post_detect {
		973	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		974	};
		975
		976	# the ||= is important in case post_detect immediately runs the block,
		977	# as to not clobber the newly-created watcher. assigning both watcher and
		978	# post_detect guard to the same variable has the advantage of users being
		979	# able to just C<undef $WATCHER> if the watcher causes them grief.
		980
		981	$WATCHER ||= $guard;
690		982
691	=item @AnyEvent::post_detect	983	=item @AnyEvent::post_detect
692		984
693	If there are any code references in this array (you can C<push> to it	985	If there are any code references in this array (you can C<push> to it
694	before or after loading AnyEvent), then they will called directly after	986	before or after loading AnyEvent), then they will called directly after
695	the event loop has been chosen.	987	the event loop has been chosen.
696		988
697	You should check C<$AnyEvent::MODEL> before adding to this array, though:	989	You should check C<$AnyEvent::MODEL> before adding to this array, though:
698	if it contains a true value then the event loop has already been detected,	990	if it is defined then the event loop has already been detected, and the
699	and the array will be ignored.	991	array will be ignored.
700		992
701	Best use C<AnyEvent::post_detect { BLOCK }> instead.	993	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		994	it, as it takes care of these details.
		995
		996	This variable is mainly useful for modules that can do something useful
		997	when AnyEvent is used and thus want to know when it is initialised, but do
		998	not need to even load it by default. This array provides the means to hook
		999	into AnyEvent passively, without loading it.
		1000
		1001	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1002	together, you could put this into Coro (this is the actual code used by
		1003	Coro to accomplish this):
		1004
		1005	if (defined $AnyEvent::MODEL) {
		1006	# AnyEvent already initialised, so load Coro::AnyEvent
		1007	require Coro::AnyEvent;
		1008	} else {
		1009	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1010	# as soon as it is
		1011	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1012	}
702		1013
703	=back	1014	=back
704		1015
705	=head1 WHAT TO DO IN A MODULE	1016	=head1 WHAT TO DO IN A MODULE
706		1017
…		…
761		1072
762		1073
763	=head1 OTHER MODULES	1074	=head1 OTHER MODULES
764		1075
765	The following is a non-exhaustive list of additional modules that use	1076	The following is a non-exhaustive list of additional modules that use
766	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1077	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
767	in the same program. Some of the modules come with AnyEvent, some are	1078	modules and other event loops in the same program. Some of the modules
768	available via CPAN.	1079	come as part of AnyEvent, the others are available via CPAN.
769		1080
770	=over 4	1081	=over 4
771		1082
772	=item L<AnyEvent::Util>	1083	=item L<AnyEvent::Util>
773		1084
…		…
782		1093
783	=item L<AnyEvent::Handle>	1094	=item L<AnyEvent::Handle>
784		1095
785	Provide read and write buffers, manages watchers for reads and writes,	1096	Provide read and write buffers, manages watchers for reads and writes,
786	supports raw and formatted I/O, I/O queued and fully transparent and	1097	supports raw and formatted I/O, I/O queued and fully transparent and
787	non-blocking SSL/TLS.	1098	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
788		1099
789	=item L<AnyEvent::DNS>	1100	=item L<AnyEvent::DNS>
790		1101
791	Provides rich asynchronous DNS resolver capabilities.	1102	Provides rich asynchronous DNS resolver capabilities.
792		1103
		1104	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1105
		1106	Implement event-based interfaces to the protocols of the same name (for
		1107	the curious, IGS is the International Go Server and FCP is the Freenet
		1108	Client Protocol).
		1109
		1110	=item L<AnyEvent::Handle::UDP>
		1111
		1112	Here be danger!
		1113
		1114	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1115	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1116	it's use of a stream-based API with a protocol that isn't streamable, that
		1117	the only way to improve it is to delete it.
		1118
		1119	It features data corruption (but typically only under load) and general
		1120	confusion. On top, the author is not only clueless about UDP but also
		1121	fact-resistant - some gems of his understanding: "connect doesn't work
		1122	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1123	packets", "I don't need to implement proper error checking as UDP doesn't
		1124	support error checking" and so on - he doesn't even understand what's
		1125	wrong with his module when it is explained to him.
		1126
793	=item L<AnyEvent::HTTP>	1127	=item L<AnyEvent::DBI>
794		1128
795	A simple-to-use HTTP library that is capable of making a lot of concurrent	1129	Executes L<DBI> requests asynchronously in a proxy process for you,
796	HTTP requests.	1130	notifying you in an event-bnased way when the operation is finished.
		1131
		1132	=item L<AnyEvent::AIO>
		1133
		1134	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1135	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1136	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1137	file I/O, and much more.
797		1138
798	=item L<AnyEvent::HTTPD>	1139	=item L<AnyEvent::HTTPD>
799		1140
800	Provides a simple web application server framework.	1141	A simple embedded webserver.
801		1142
802	=item L<AnyEvent::FastPing>	1143	=item L<AnyEvent::FastPing>
803		1144
804	The fastest ping in the west.	1145	The fastest ping in the west.
805		1146
806	=item L<AnyEvent::DBI>
807
808	Executes L<DBI> requests asynchronously in a proxy process.
809
810	=item L<AnyEvent::AIO>
811
812	Truly asynchronous I/O, should be in the toolbox of every event
813	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
814	together.
815
816	=item L<AnyEvent::BDB>
817
818	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
819	L<BDB> and AnyEvent together.
820
821	=item L<AnyEvent::GPSD>
822
823	A non-blocking interface to gpsd, a daemon delivering GPS information.
824
825	=item L<AnyEvent::IGS>
826
827	A non-blocking interface to the Internet Go Server protocol (used by
828	L<App::IGS>).
829
830	=item L<AnyEvent::IRC>
831
832	AnyEvent based IRC client module family (replacing the older Net::IRC3).
833
834	=item L<Net::XMPP2>
835
836	AnyEvent based XMPP (Jabber protocol) module family.
837
838	=item L<Net::FCP>
839
840	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
841	of AnyEvent.
842
843	=item L<Event::ExecFlow>
844
845	High level API for event-based execution flow control.
846
847	=item L<Coro>	1147	=item L<Coro>
848		1148
849	Has special support for AnyEvent via L<Coro::AnyEvent>.	1149	Has special support for AnyEvent via L<Coro::AnyEvent>.
850		1150
851	=item L<IO::Lambda>
852
853	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
854
855	=back	1151	=back
856		1152
857	=cut	1153	=cut
858		1154
859	package AnyEvent;	1155	package AnyEvent;
860		1156
861	no warnings;	1157	# basically a tuned-down version of common::sense
862	use strict qw(vars subs);	1158	sub common_sense {
		1159	# from common:.sense 1.0
		1160	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
		1161	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1162	$^H |= 0x00000600;
		1163	}
863		1164
		1165	BEGIN { AnyEvent::common_sense }
		1166
864	use Carp;	1167	use Carp ();
865		1168
866	our $VERSION = 4.32;	1169	our $VERSION = '5.271';
867	our $MODEL;	1170	our $MODEL;
868		1171
869	our $AUTOLOAD;	1172	our $AUTOLOAD;
870	our @ISA;	1173	our @ISA;
871		1174
872	our @REGISTRY;	1175	our @REGISTRY;
873		1176
874	our $WIN32;	1177	our $VERBOSE;
875		1178
876	BEGIN {	1179	BEGIN {
877	my $win32 = ! ! ($^O =~ /mswin32/i);	1180	require "AnyEvent/constants.pl";
878	eval "sub WIN32(){ $win32 }";
879	}
880		1181
		1182	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
		1183
		1184	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1185	if ${^TAINT};
		1186
881	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1187	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1188
		1189	}
		1190
		1191	our $MAX_SIGNAL_LATENCY = 10;
882		1192
883	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1193	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
884		1194
885	{	1195	{
886	my $idx;	1196	my $idx;
…		…
888	for reverse split /\s*,\s*/,	1198	for reverse split /\s*,\s*/,
889	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1199	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
890	}	1200	}
891		1201
892	my @models = (	1202	my @models = (
893	[EV:: => AnyEvent::Impl::EV::],	1203	[EV:: => AnyEvent::Impl::EV:: , 1],
894	[Event:: => AnyEvent::Impl::Event::],
895	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1204	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
896	# everything below here will not be autoprobed	1205	# everything below here will not (normally) be autoprobed
897	# as the pureperl backend should work everywhere	1206	# as the pureperl backend should work everywhere
898	# and is usually faster	1207	# and is usually faster
		1208	[Event:: => AnyEvent::Impl::Event::, 1],
		1209	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1210	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1211	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
899	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1212	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
900	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
901	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
902	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1213	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
903	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1214	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
904	[Wx:: => AnyEvent::Impl::POE::],	1215	[Wx:: => AnyEvent::Impl::POE::],
905	[Prima:: => AnyEvent::Impl::POE::],	1216	[Prima:: => AnyEvent::Impl::POE::],
		1217	# IO::Async is just too broken - we would need workarounds for its
		1218	# byzantine signal and broken child handling, among others.
		1219	# IO::Async is rather hard to detect, as it doesn't have any
		1220	# obvious default class.
		1221	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1222	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1223	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1224	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
906	);	1225	);
907		1226
908	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1227	our %method = map +($_ => 1),
		1228	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
909		1229
910	our @post_detect;	1230	our @post_detect;
911		1231
912	sub post_detect(&) {	1232	sub post_detect(&) {
913	my ($cb) = @_;	1233	my ($cb) = @_;
914		1234
915	if ($MODEL) {
916	$cb->();
917
918	1
919	} else {
920	push @post_detect, $cb;	1235	push @post_detect, $cb;
921		1236
922	defined wantarray	1237	defined wantarray
923	? bless \$cb, "AnyEvent::Util::PostDetect"	1238	? bless \$cb, "AnyEvent::Util::postdetect"
924	: ()	1239	: ()
		1240	}
		1241
		1242	sub AnyEvent::Util::postdetect::DESTROY {
		1243	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1244	}
		1245
		1246	sub detect() {
		1247	# free some memory
		1248	*detect = sub () { $MODEL };
		1249
		1250	local $!; # for good measure
		1251	local $SIG{__DIE__};
		1252
		1253	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1254	my $model = "AnyEvent::Impl::$1";
		1255	if (eval "require $model") {
		1256	$MODEL = $model;
		1257	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1258	} else {
		1259	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1260	}
925	}	1261	}
926	}
927		1262
928	sub AnyEvent::Util::PostDetect::DESTROY {	1263	# check for already loaded models
929	@post_detect = grep $_ != ${$_[0]}, @post_detect;
930	}
931
932	sub detect() {
933	unless ($MODEL) {	1264	unless ($MODEL) {
934	no strict 'refs';	1265	for (@REGISTRY, @models) {
935	local $SIG{__DIE__};	1266	my ($package, $model) = @$_;
936		1267	if (${"$package\::VERSION"} > 0) {
937	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
938	my $model = "AnyEvent::Impl::$1";
939	if (eval "require $model") {	1268	if (eval "require $model") {
940	$MODEL = $model;	1269	$MODEL = $model;
941	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1270	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
942	} else {	1271	last;
943	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1272	}
944	}	1273	}
945	}	1274	}
946		1275
947	# check for already loaded models
948	unless ($MODEL) {	1276	unless ($MODEL) {
		1277	# try to autoload a model
949	for (@REGISTRY, @models) {	1278	for (@REGISTRY, @models) {
950	my ($package, $model) = @$_;	1279	my ($package, $model, $autoload) = @$_;
		1280	if (
		1281	$autoload
		1282	and eval "require $package"
951	if (${"$package\::VERSION"} > 0) {	1283	and ${"$package\::VERSION"} > 0
952	if (eval "require $model") {	1284	and eval "require $model"
		1285	) {
953	$MODEL = $model;	1286	$MODEL = $model;
954	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1287	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
955	last;	1288	last;
956	}
957	}	1289	}
958	}	1290	}
959		1291
960	unless ($MODEL) {
961	# try to load a model
962
963	for (@REGISTRY, @models) {
964	my ($package, $model) = @$_;
965	if (eval "require $package"
966	and ${"$package\::VERSION"} > 0
967	and eval "require $model") {
968	$MODEL = $model;
969	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
970	last;
971	}
972	}
973
974	$MODEL	1292	$MODEL
975	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1293	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
976	}
977	}	1294	}
978
979	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
980
981	unshift @ISA, $MODEL;
982
983	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
984
985	(shift @post_detect)->() while @post_detect;
986	}	1295	}
		1296
		1297	@models = (); # free probe data
		1298
		1299	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1300	unshift @ISA, $MODEL;
		1301
		1302	# now nuke some methods that are overriden by the backend.
		1303	# SUPER is not allowed.
		1304	for (qw(time signal child idle)) {
		1305	undef &{"AnyEvent::Base::$_"}
		1306	if defined &{"$MODEL\::$_"};
		1307	}
		1308
		1309	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1310
		1311	(shift @post_detect)->() while @post_detect;
		1312
		1313	*post_detect = sub(&) {
		1314	shift->();
		1315
		1316	undef
		1317	};
987		1318
988	$MODEL	1319	$MODEL
989	}	1320	}
990		1321
991	sub AUTOLOAD {	1322	sub AUTOLOAD {
992	(my $func = $AUTOLOAD) =~ s/.*://;	1323	(my $func = $AUTOLOAD) =~ s/.*://;
993		1324
994	$method{$func}	1325	$method{$func}
995	or croak "$func: not a valid method for AnyEvent objects";	1326	or Carp::croak "$func: not a valid AnyEvent class method";
996		1327
997	detect unless $MODEL;	1328	detect;
998		1329
999	my $class = shift;	1330	my $class = shift;
1000	$class->$func (@_);	1331	$class->$func (@_);
1001	}	1332	}
1002		1333
1003	# utility function to dup a filehandle. this is used by many backends	1334	# utility function to dup a filehandle. this is used by many backends
1004	# to support binding more than one watcher per filehandle (they usually	1335	# to support binding more than one watcher per filehandle (they usually
1005	# allow only one watcher per fd, so we dup it to get a different one).	1336	# allow only one watcher per fd, so we dup it to get a different one).
1006	sub _dupfh($$$$) {	1337	sub _dupfh($$;$$) {
1007	my ($poll, $fh, $r, $w) = @_;	1338	my ($poll, $fh, $r, $w) = @_;
1008		1339
1009	require Fcntl;
1010
1011	# cygwin requires the fh mode to be matching, unix doesn't	1340	# cygwin requires the fh mode to be matching, unix doesn't
1012	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1341	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1013	: $poll eq "w" ? ($w, ">")
1014	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1015		1342
1016	open my $fh2, "$mode&" . fileno $fh	1343	open my $fh2, $mode, $fh
1017	or die "cannot dup() filehandle: $!";	1344	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1018		1345
1019	# we assume CLOEXEC is already set by perl in all important cases	1346	# we assume CLOEXEC is already set by perl in all important cases
1020		1347
1021	($fh2, $rw)	1348	($fh2, $rw)
1022	}	1349	}
1023		1350
		1351	=head1 SIMPLIFIED AE API
		1352
		1353	Starting with version 5.0, AnyEvent officially supports a second, much
		1354	simpler, API that is designed to reduce the calling, typing and memory
		1355	overhead by using function call syntax and a fixed number of parameters.
		1356
		1357	See the L<AE> manpage for details.
		1358
		1359	=cut
		1360
		1361	package AE;
		1362
		1363	our $VERSION = $AnyEvent::VERSION;
		1364
		1365	# fall back to the main API by default - backends and AnyEvent::Base
		1366	# implementations can overwrite these.
		1367
		1368	sub io($$$) {
		1369	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1370	}
		1371
		1372	sub timer($$$) {
		1373	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1374	}
		1375
		1376	sub signal($$) {
		1377	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1378	}
		1379
		1380	sub child($$) {
		1381	AnyEvent->child (pid => $_[0], cb => $_[1])
		1382	}
		1383
		1384	sub idle($) {
		1385	AnyEvent->idle (cb => $_[0])
		1386	}
		1387
		1388	sub cv(;&) {
		1389	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1390	}
		1391
		1392	sub now() {
		1393	AnyEvent->now
		1394	}
		1395
		1396	sub now_update() {
		1397	AnyEvent->now_update
		1398	}
		1399
		1400	sub time() {
		1401	AnyEvent->time
		1402	}
		1403
1024	package AnyEvent::Base;	1404	package AnyEvent::Base;
1025		1405
1026	# default implementation for now and time	1406	# default implementations for many methods
1027		1407
1028	BEGIN {	1408	sub time {
		1409	eval q{ # poor man's autoloading {}
		1410	# probe for availability of Time::HiRes
1029	if (eval "use Time::HiRes (); time (); 1") {	1411	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1412	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1030	*_time = \&Time::HiRes::time;	1413	*AE::time = \&Time::HiRes::time;
1031	# if (eval "use POSIX (); (POSIX::times())...	1414	# if (eval "use POSIX (); (POSIX::times())...
1032	} else {	1415	} else {
		1416	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1033	*_time = sub { time }; # epic fail	1417	*AE::time = sub (){ time }; # epic fail
		1418	}
		1419
		1420	*time = sub { AE::time }; # different prototypes
		1421	};
		1422	die if $@;
		1423
		1424	&time
		1425	}
		1426
		1427	*now = \&time;
		1428
		1429	sub now_update { }
		1430
		1431	# default implementation for ->condvar
		1432
		1433	sub condvar {
		1434	eval q{ # poor man's autoloading {}
		1435	*condvar = sub {
		1436	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1437	};
		1438
		1439	*AE::cv = sub (;&) {
		1440	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1441	};
		1442	};
		1443	die if $@;
		1444
		1445	&condvar
		1446	}
		1447
		1448	# default implementation for ->signal
		1449
		1450	our $HAVE_ASYNC_INTERRUPT;
		1451
		1452	sub _have_async_interrupt() {
		1453	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1454	&& eval "use Async::Interrupt 1.02 (); 1")
		1455	unless defined $HAVE_ASYNC_INTERRUPT;
		1456
		1457	$HAVE_ASYNC_INTERRUPT
		1458	}
		1459
		1460	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1461	our (%SIG_ASY, %SIG_ASY_W);
		1462	our ($SIG_COUNT, $SIG_TW);
		1463
		1464	# install a dummy wakeup watcher to reduce signal catching latency
		1465	# used by Impls
		1466	sub _sig_add() {
		1467	unless ($SIG_COUNT++) {
		1468	# try to align timer on a full-second boundary, if possible
		1469	my $NOW = AE::now;
		1470
		1471	$SIG_TW = AE::timer
		1472	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1473	$MAX_SIGNAL_LATENCY,
		1474	sub { } # just for the PERL_ASYNC_CHECK
		1475	;
1034	}	1476	}
1035	}	1477	}
1036		1478
1037	sub time { _time }	1479	sub _sig_del {
1038	sub now { _time }	1480	undef $SIG_TW
1039		1481	unless --$SIG_COUNT;
1040	# default implementation for ->condvar
1041
1042	sub condvar {
1043	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
1044	}	1482	}
1045		1483
1046	# default implementation for ->signal	1484	our $_sig_name_init; $_sig_name_init = sub {
		1485	eval q{ # poor man's autoloading {}
		1486	undef $_sig_name_init;
1047		1487
1048	our %SIG_CB;	1488	if (_have_async_interrupt) {
		1489	*sig2num = \&Async::Interrupt::sig2num;
		1490	*sig2name = \&Async::Interrupt::sig2name;
		1491	} else {
		1492	require Config;
		1493
		1494	my %signame2num;
		1495	@signame2num{ split ' ', $Config::Config{sig_name} }
		1496	= split ' ', $Config::Config{sig_num};
		1497
		1498	my @signum2name;
		1499	@signum2name[values %signame2num] = keys %signame2num;
		1500
		1501	*sig2num = sub($) {
		1502	$_[0] > 0 ? shift : $signame2num{+shift}
		1503	};
		1504	*sig2name = sub ($) {
		1505	$_[0] > 0 ? $signum2name[+shift] : shift
		1506	};
		1507	}
		1508	};
		1509	die if $@;
		1510	};
		1511
		1512	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1513	sub sig2name($) { &$_sig_name_init; &sig2name }
1049		1514
1050	sub signal {	1515	sub signal {
		1516	eval q{ # poor man's autoloading {}
		1517	# probe for availability of Async::Interrupt
		1518	if (_have_async_interrupt) {
		1519	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
		1520
		1521	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1522	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
		1523
		1524	} else {
		1525	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1526
		1527	if (AnyEvent::WIN32) {
		1528	require AnyEvent::Util;
		1529
		1530	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1531	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1532	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1533	} else {
		1534	pipe $SIGPIPE_R, $SIGPIPE_W;
		1535	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
		1536	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1537
		1538	# not strictly required, as $^F is normally 2, but let's make sure...
		1539	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1540	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1541	}
		1542
		1543	$SIGPIPE_R
		1544	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1545
		1546	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
		1547	}
		1548
		1549	*signal = $HAVE_ASYNC_INTERRUPT
		1550	? sub {
1051	my (undef, %arg) = @_;	1551	my (undef, %arg) = @_;
1052		1552
		1553	# async::interrupt
1053	my $signal = uc $arg{signal}	1554	my $signal = sig2num $arg{signal};
1054	or Carp::croak "required option 'signal' is missing";
1055
1056	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1555	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1556
		1557	$SIG_ASY{$signal} ||= new Async::Interrupt
		1558	cb => sub { undef $SIG_EV{$signal} },
		1559	signal => $signal,
		1560	pipe => [$SIGPIPE_R->filenos],
		1561	pipe_autodrain => 0,
		1562	;
		1563
		1564	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1565	}
		1566	: sub {
		1567	my (undef, %arg) = @_;
		1568
		1569	# pure perl
		1570	my $signal = sig2name $arg{signal};
		1571	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1572
1057	$SIG{$signal} ||= sub {	1573	$SIG{$signal} ||= sub {
		1574	local $!;
		1575	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1576	undef $SIG_EV{$signal};
		1577	};
		1578
		1579	# can't do signal processing without introducing races in pure perl,
		1580	# so limit the signal latency.
		1581	_sig_add;
		1582
		1583	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1584	}
		1585	;
		1586
		1587	*AnyEvent::Base::signal::DESTROY = sub {
		1588	my ($signal, $cb) = @{$_[0]};
		1589
		1590	_sig_del;
		1591
		1592	delete $SIG_CB{$signal}{$cb};
		1593
		1594	$HAVE_ASYNC_INTERRUPT
		1595	? delete $SIG_ASY{$signal}
		1596	: # delete doesn't work with older perls - they then
		1597	# print weird messages, or just unconditionally exit
		1598	# instead of getting the default action.
		1599	undef $SIG{$signal}
		1600	unless keys %{ $SIG_CB{$signal} };
		1601	};
		1602
		1603	*_signal_exec = sub {
		1604	$HAVE_ASYNC_INTERRUPT
		1605	? $SIGPIPE_R->drain
		1606	: sysread $SIGPIPE_R, (my $dummy), 9;
		1607
		1608	while (%SIG_EV) {
		1609	for (keys %SIG_EV) {
		1610	delete $SIG_EV{$_};
1058	$_->() for values %{ $SIG_CB{$signal} || {} };	1611	$_->() for values %{ $SIG_CB{$_} || {} };
		1612	}
		1613	}
		1614	};
1059	};	1615	};
		1616	die if $@;
1060		1617
1061	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1618	&signal
1062	}
1063
1064	sub AnyEvent::Base::Signal::DESTROY {
1065	my ($signal, $cb) = @{$_[0]};
1066
1067	delete $SIG_CB{$signal}{$cb};
1068
1069	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1070	}	1619	}
1071		1620
1072	# default implementation for ->child	1621	# default implementation for ->child
1073		1622
1074	our %PID_CB;	1623	our %PID_CB;
1075	our $CHLD_W;	1624	our $CHLD_W;
1076	our $CHLD_DELAY_W;	1625	our $CHLD_DELAY_W;
1077	our $PID_IDLE;
1078	our $WNOHANG;	1626	our $WNOHANG;
1079		1627
1080	sub _child_wait {	1628	# used by many Impl's
1081	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1629	sub _emit_childstatus($$) {
		1630	my (undef, $rpid, $rstatus) = @_;
		1631
		1632	$_->($rpid, $rstatus)
1082	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1633	for values %{ $PID_CB{$rpid} || {} },
1083	(values %{ $PID_CB{0} || {} });	1634	values %{ $PID_CB{0} || {} };
1084	}
1085
1086	undef $PID_IDLE;
1087	}
1088
1089	sub _sigchld {
1090	# make sure we deliver these changes "synchronous" with the event loop.
1091	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
1092	undef $CHLD_DELAY_W;
1093	&_child_wait;
1094	});
1095	}	1635	}
1096		1636
1097	sub child {	1637	sub child {
		1638	eval q{ # poor man's autoloading {}
		1639	*_sigchld = sub {
		1640	my $pid;
		1641
		1642	AnyEvent->_emit_childstatus ($pid, $?)
		1643	while ($pid = waitpid -1, $WNOHANG) > 0;
		1644	};
		1645
		1646	*child = sub {
1098	my (undef, %arg) = @_;	1647	my (undef, %arg) = @_;
1099		1648
1100	defined (my $pid = $arg{pid} + 0)	1649	defined (my $pid = $arg{pid} + 0)
1101	or Carp::croak "required option 'pid' is missing";	1650	or Carp::croak "required option 'pid' is missing";
1102		1651
1103	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1652	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1104		1653
1105	unless ($WNOHANG) {	1654	# WNOHANG is almost cetrainly 1 everywhere
		1655	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1656	? 1
1106	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1657	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1107	}
1108		1658
1109	unless ($CHLD_W) {	1659	unless ($CHLD_W) {
1110	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1660	$CHLD_W = AE::signal CHLD => \&_sigchld;
1111	# child could be a zombie already, so make at least one round	1661	# child could be a zombie already, so make at least one round
1112	&_sigchld;	1662	&_sigchld;
1113	}	1663	}
1114		1664
1115	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1665	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1116	}	1666	};
1117		1667
1118	sub AnyEvent::Base::Child::DESTROY {	1668	*AnyEvent::Base::child::DESTROY = sub {
1119	my ($pid, $cb) = @{$_[0]};	1669	my ($pid, $cb) = @{$_[0]};
1120		1670
1121	delete $PID_CB{$pid}{$cb};	1671	delete $PID_CB{$pid}{$cb};
1122	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1672	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1123		1673
1124	undef $CHLD_W unless keys %PID_CB;	1674	undef $CHLD_W unless keys %PID_CB;
		1675	};
		1676	};
		1677	die if $@;
		1678
		1679	&child
		1680	}
		1681
		1682	# idle emulation is done by simply using a timer, regardless
		1683	# of whether the process is idle or not, and not letting
		1684	# the callback use more than 50% of the time.
		1685	sub idle {
		1686	eval q{ # poor man's autoloading {}
		1687	*idle = sub {
		1688	my (undef, %arg) = @_;
		1689
		1690	my ($cb, $w, $rcb) = $arg{cb};
		1691
		1692	$rcb = sub {
		1693	if ($cb) {
		1694	$w = _time;
		1695	&$cb;
		1696	$w = _time - $w;
		1697
		1698	# never use more then 50% of the time for the idle watcher,
		1699	# within some limits
		1700	$w = 0.0001 if $w < 0.0001;
		1701	$w = 5 if $w > 5;
		1702
		1703	$w = AE::timer $w, 0, $rcb;
		1704	} else {
		1705	# clean up...
		1706	undef $w;
		1707	undef $rcb;
		1708	}
		1709	};
		1710
		1711	$w = AE::timer 0.05, 0, $rcb;
		1712
		1713	bless \\$cb, "AnyEvent::Base::idle"
		1714	};
		1715
		1716	*AnyEvent::Base::idle::DESTROY = sub {
		1717	undef $${$_[0]};
		1718	};
		1719	};
		1720	die if $@;
		1721
		1722	&idle
1125	}	1723	}
1126		1724
1127	package AnyEvent::CondVar;	1725	package AnyEvent::CondVar;
1128		1726
1129	our @ISA = AnyEvent::CondVar::Base::;	1727	our @ISA = AnyEvent::CondVar::Base::;
1130		1728
1131	package AnyEvent::CondVar::Base;	1729	package AnyEvent::CondVar::Base;
1132		1730
1133	use overload	1731	#use overload
1134	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1732	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1135	fallback => 1;	1733	# fallback => 1;
		1734
		1735	# save 300+ kilobytes by dirtily hardcoding overloading
		1736	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1737	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1738	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1739	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1740
		1741	our $WAITING;
1136		1742
1137	sub _send {	1743	sub _send {
1138	# nop	1744	# nop
1139	}	1745	}
1140		1746
…		…
1153	sub ready {	1759	sub ready {
1154	$_[0]{_ae_sent}	1760	$_[0]{_ae_sent}
1155	}	1761	}
1156		1762
1157	sub _wait {	1763	sub _wait {
		1764	$WAITING
		1765	and !$_[0]{_ae_sent}
		1766	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1767
		1768	local $WAITING = 1;
1158	AnyEvent->one_event while !$_[0]{_ae_sent};	1769	AnyEvent->one_event while !$_[0]{_ae_sent};
1159	}	1770	}
1160		1771
1161	sub recv {	1772	sub recv {
1162	$_[0]->_wait;	1773	$_[0]->_wait;
…		…
1164	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1775	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1165	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1776	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1166	}	1777	}
1167		1778
1168	sub cb {	1779	sub cb {
1169	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1780	my $cv = shift;
		1781
		1782	@_
		1783	and $cv->{_ae_cb} = shift
		1784	and $cv->{_ae_sent}
		1785	and (delete $cv->{_ae_cb})->($cv);
		1786
1170	$_[0]{_ae_cb}	1787	$cv->{_ae_cb}
1171	}	1788	}
1172		1789
1173	sub begin {	1790	sub begin {
1174	++$_[0]{_ae_counter};	1791	++$_[0]{_ae_counter};
1175	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1792	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1203	so on.	1820	so on.
1204		1821
1205	=head1 ENVIRONMENT VARIABLES	1822	=head1 ENVIRONMENT VARIABLES
1206		1823
1207	The following environment variables are used by this module or its	1824	The following environment variables are used by this module or its
1208	submodules:	1825	submodules.
		1826
		1827	Note that AnyEvent will remove I<all> environment variables starting with
		1828	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1829	enabled.
1209		1830
1210	=over 4	1831	=over 4
1211		1832
1212	=item C<PERL_ANYEVENT_VERBOSE>	1833	=item C<PERL_ANYEVENT_VERBOSE>
1213		1834
…		…
1220	C<PERL_ANYEVENT_MODEL>.	1841	C<PERL_ANYEVENT_MODEL>.
1221		1842
1222	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1843	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1223	model it chooses.	1844	model it chooses.
1224		1845
		1846	When set to C<8> or higher, then AnyEvent will report extra information on
		1847	which optional modules it loads and how it implements certain features.
		1848
1225	=item C<PERL_ANYEVENT_STRICT>	1849	=item C<PERL_ANYEVENT_STRICT>
1226		1850
1227	AnyEvent does not do much argument checking by default, as thorough	1851	AnyEvent does not do much argument checking by default, as thorough
1228	argument checking is very costly. Setting this variable to a true value	1852	argument checking is very costly. Setting this variable to a true value
1229	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1853	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1230	check the arguments passed to most method calls. If it finds any problems	1854	check the arguments passed to most method calls. If it finds any problems,
1231	it will croak.	1855	it will croak.
1232		1856
1233	In other words, enables "strict" mode.	1857	In other words, enables "strict" mode.
1234		1858
1235	Unlike C<use strict>, it is definitely recommended ot keep it off in	1859	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1236	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1860	>>, it is definitely recommended to keep it off in production. Keeping
1237	developing programs can be very useful, however.	1861	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1862	can be very useful, however.
1238		1863
1239	=item C<PERL_ANYEVENT_MODEL>	1864	=item C<PERL_ANYEVENT_MODEL>
1240		1865
1241	This can be used to specify the event model to be used by AnyEvent, before	1866	This can be used to specify the event model to be used by AnyEvent, before
1242	auto detection and -probing kicks in. It must be a string consisting	1867	auto detection and -probing kicks in. It must be a string consisting
…		…
1263	used, and preference will be given to protocols mentioned earlier in the	1888	used, and preference will be given to protocols mentioned earlier in the
1264	list.	1889	list.
1265		1890
1266	This variable can effectively be used for denial-of-service attacks	1891	This variable can effectively be used for denial-of-service attacks
1267	against local programs (e.g. when setuid), although the impact is likely	1892	against local programs (e.g. when setuid), although the impact is likely
1268	small, as the program has to handle connection errors already-	1893	small, as the program has to handle conenction and other failures anyways.
1269		1894
1270	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,	1895	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1271	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>	1896	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1272	- only support IPv4, never try to resolve or contact IPv6	1897	- only support IPv4, never try to resolve or contact IPv6
1273	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or	1898	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
…		…
1285		1910
1286	=item C<PERL_ANYEVENT_MAX_FORKS>	1911	=item C<PERL_ANYEVENT_MAX_FORKS>
1287		1912
1288	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1913	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1289	will create in parallel.	1914	will create in parallel.
		1915
		1916	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1917
		1918	The default value for the C<max_outstanding> parameter for the default DNS
		1919	resolver - this is the maximum number of parallel DNS requests that are
		1920	sent to the DNS server.
		1921
		1922	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1923
		1924	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1925	configuration) in the default resolver. When set to the empty string, no
		1926	default config will be used.
		1927
		1928	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1929
		1930	When neither C<ca_file> nor C<ca_path> was specified during
		1931	L<AnyEvent::TLS> context creation, and either of these environment
		1932	variables exist, they will be used to specify CA certificate locations
		1933	instead of a system-dependent default.
		1934
		1935	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1936
		1937	When these are set to C<1>, then the respective modules are not
		1938	loaded. Mostly good for testing AnyEvent itself.
1290		1939
1291	=back	1940	=back
1292		1941
1293	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1942	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1294		1943
…		…
1352	warn "read: $input\n"; # output what has been read	2001	warn "read: $input\n"; # output what has been read
1353	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2002	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1354	},	2003	},
1355	);	2004	);
1356		2005
1357	my $time_watcher; # can only be used once
1358
1359	sub new_timer {
1360	$timer = AnyEvent->timer (after => 1, cb => sub {	2006	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1361	warn "timeout\n"; # print 'timeout' about every second	2007	warn "timeout\n"; # print 'timeout' at most every second
1362	&new_timer; # and restart the time
1363	});	2008	});
1364	}
1365
1366	new_timer; # create first timer
1367		2009
1368	$cv->recv; # wait until user enters /^q/i	2010	$cv->recv; # wait until user enters /^q/i
1369		2011
1370	=head1 REAL-WORLD EXAMPLE	2012	=head1 REAL-WORLD EXAMPLE
1371		2013
…		…
1444		2086
1445	The actual code goes further and collects all errors (C<die>s, exceptions)	2087	The actual code goes further and collects all errors (C<die>s, exceptions)
1446	that occurred during request processing. The C<result> method detects	2088	that occurred during request processing. The C<result> method detects
1447	whether an exception as thrown (it is stored inside the $txn object)	2089	whether an exception as thrown (it is stored inside the $txn object)
1448	and just throws the exception, which means connection errors and other	2090	and just throws the exception, which means connection errors and other
1449	problems get reported tot he code that tries to use the result, not in a	2091	problems get reported to the code that tries to use the result, not in a
1450	random callback.	2092	random callback.
1451		2093
1452	All of this enables the following usage styles:	2094	All of this enables the following usage styles:
1453		2095
1454	1. Blocking:	2096	1. Blocking:
…		…
1502	through AnyEvent. The benchmark creates a lot of timers (with a zero	2144	through AnyEvent. The benchmark creates a lot of timers (with a zero
1503	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2145	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1504	which it is), lets them fire exactly once and destroys them again.	2146	which it is), lets them fire exactly once and destroys them again.
1505		2147
1506	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2148	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1507	distribution.	2149	distribution. It uses the L<AE> interface, which makes a real difference
		2150	for the EV and Perl backends only.
1508		2151
1509	=head3 Explanation of the columns	2152	=head3 Explanation of the columns
1510		2153
1511	I<watcher> is the number of event watchers created/destroyed. Since	2154	I<watcher> is the number of event watchers created/destroyed. Since
1512	different event models feature vastly different performances, each event	2155	different event models feature vastly different performances, each event
…		…
1533	watcher.	2176	watcher.
1534		2177
1535	=head3 Results	2178	=head3 Results
1536		2179
1537	name watchers bytes create invoke destroy comment	2180	name watchers bytes create invoke destroy comment
1538	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2181	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1539	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2182	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1540	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2183	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1541	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2184	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1542	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2185	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1543	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2186	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2187	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2188	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1544	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2189	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1545	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2190	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1546	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2191	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1547	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2192	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1548		2193
1549	=head3 Discussion	2194	=head3 Discussion
1550		2195
1551	The benchmark does I<not> measure scalability of the event loop very	2196	The benchmark does I<not> measure scalability of the event loop very
1552	well. For example, a select-based event loop (such as the pure perl one)	2197	well. For example, a select-based event loop (such as the pure perl one)
…		…
1564	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2209	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1565	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2210	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1566	cycles with POE.	2211	cycles with POE.
1567		2212
1568	C<EV> is the sole leader regarding speed and memory use, which are both	2213	C<EV> is the sole leader regarding speed and memory use, which are both
1569	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2214	maximal/minimal, respectively. When using the L<AE> API there is zero
		2215	overhead (when going through the AnyEvent API create is about 5-6 times
		2216	slower, with other times being equal, so still uses far less memory than
1570	far less memory than any other event loop and is still faster than Event	2217	any other event loop and is still faster than Event natively).
1571	natively.
1572		2218
1573	The pure perl implementation is hit in a few sweet spots (both the	2219	The pure perl implementation is hit in a few sweet spots (both the
1574	constant timeout and the use of a single fd hit optimisations in the perl	2220	constant timeout and the use of a single fd hit optimisations in the perl
1575	interpreter and the backend itself). Nevertheless this shows that it	2221	interpreter and the backend itself). Nevertheless this shows that it
1576	adds very little overhead in itself. Like any select-based backend its	2222	adds very little overhead in itself. Like any select-based backend its
1577	performance becomes really bad with lots of file descriptors (and few of	2223	performance becomes really bad with lots of file descriptors (and few of
1578	them active), of course, but this was not subject of this benchmark.	2224	them active), of course, but this was not subject of this benchmark.
1579		2225
1580	The C<Event> module has a relatively high setup and callback invocation	2226	The C<Event> module has a relatively high setup and callback invocation
1581	cost, but overall scores in on the third place.	2227	cost, but overall scores in on the third place.
		2228
		2229	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2230	when using its pure perl backend.
1582		2231
1583	C<Glib>'s memory usage is quite a bit higher, but it features a	2232	C<Glib>'s memory usage is quite a bit higher, but it features a
1584	faster callback invocation and overall ends up in the same class as	2233	faster callback invocation and overall ends up in the same class as
1585	C<Event>. However, Glib scales extremely badly, doubling the number of	2234	C<Event>. However, Glib scales extremely badly, doubling the number of
1586	watchers increases the processing time by more than a factor of four,	2235	watchers increases the processing time by more than a factor of four,
…		…
1647	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2296	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1648	(1%) are active. This mirrors the activity of large servers with many	2297	(1%) are active. This mirrors the activity of large servers with many
1649	connections, most of which are idle at any one point in time.	2298	connections, most of which are idle at any one point in time.
1650		2299
1651	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2300	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1652	distribution.	2301	distribution. It uses the L<AE> interface, which makes a real difference
		2302	for the EV and Perl backends only.
1653		2303
1654	=head3 Explanation of the columns	2304	=head3 Explanation of the columns
1655		2305
1656	I<sockets> is the number of sockets, and twice the number of "servers" (as	2306	I<sockets> is the number of sockets, and twice the number of "servers" (as
1657	each server has a read and write socket end).	2307	each server has a read and write socket end).
…		…
1664	it to another server. This includes deleting the old timeout and creating	2314	it to another server. This includes deleting the old timeout and creating
1665	a new one that moves the timeout into the future.	2315	a new one that moves the timeout into the future.
1666		2316
1667	=head3 Results	2317	=head3 Results
1668		2318
1669	name sockets create request	2319	name sockets create request
1670	EV 20000 69.01 11.16	2320	EV 20000 62.66 7.99
1671	Perl 20000 73.32 35.87	2321	Perl 20000 68.32 32.64
1672	Event 20000 212.62 257.32	2322	IOAsync 20000 174.06 101.15 epoll
1673	Glib 20000 651.16 1896.30	2323	IOAsync 20000 174.67 610.84 poll
		2324	Event 20000 202.69 242.91
		2325	Glib 20000 557.01 1689.52
1674	POE 20000 349.67 12317.24 uses POE::Loop::Event	2326	POE 20000 341.54 12086.32 uses POE::Loop::Event
1675		2327
1676	=head3 Discussion	2328	=head3 Discussion
1677		2329
1678	This benchmark I<does> measure scalability and overall performance of the	2330	This benchmark I<does> measure scalability and overall performance of the
1679	particular event loop.	2331	particular event loop.
…		…
1681	EV is again fastest. Since it is using epoll on my system, the setup time	2333	EV is again fastest. Since it is using epoll on my system, the setup time
1682	is relatively high, though.	2334	is relatively high, though.
1683		2335
1684	Perl surprisingly comes second. It is much faster than the C-based event	2336	Perl surprisingly comes second. It is much faster than the C-based event
1685	loops Event and Glib.	2337	loops Event and Glib.
		2338
		2339	IO::Async performs very well when using its epoll backend, and still quite
		2340	good compared to Glib when using its pure perl backend.
1686		2341
1687	Event suffers from high setup time as well (look at its code and you will	2342	Event suffers from high setup time as well (look at its code and you will
1688	understand why). Callback invocation also has a high overhead compared to	2343	understand why). Callback invocation also has a high overhead compared to
1689	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2344	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1690	uses select or poll in basically all documented configurations.	2345	uses select or poll in basically all documented configurations.
…		…
1753	=item * C-based event loops perform very well with small number of	2408	=item * C-based event loops perform very well with small number of
1754	watchers, as the management overhead dominates.	2409	watchers, as the management overhead dominates.
1755		2410
1756	=back	2411	=back
1757		2412
		2413	=head2 THE IO::Lambda BENCHMARK
		2414
		2415	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2416	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2417	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2418	shouldn't come as a surprise to anybody). As such, the benchmark is
		2419	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2420	very optimal. But how would AnyEvent compare when used without the extra
		2421	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2422
		2423	The benchmark itself creates an echo-server, and then, for 500 times,
		2424	connects to the echo server, sends a line, waits for the reply, and then
		2425	creates the next connection. This is a rather bad benchmark, as it doesn't
		2426	test the efficiency of the framework or much non-blocking I/O, but it is a
		2427	benchmark nevertheless.
		2428
		2429	name runtime
		2430	Lambda/select 0.330 sec
		2431	+ optimized 0.122 sec
		2432	Lambda/AnyEvent 0.327 sec
		2433	+ optimized 0.138 sec
		2434	Raw sockets/select 0.077 sec
		2435	POE/select, components 0.662 sec
		2436	POE/select, raw sockets 0.226 sec
		2437	POE/select, optimized 0.404 sec
		2438
		2439	AnyEvent/select/nb 0.085 sec
		2440	AnyEvent/EV/nb 0.068 sec
		2441	+state machine 0.134 sec
		2442
		2443	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2444	benchmarks actually make blocking connects and use 100% blocking I/O,
		2445	defeating the purpose of an event-based solution. All of the newly
		2446	written AnyEvent benchmarks use 100% non-blocking connects (using
		2447	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2448	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2449	generally require a lot more bookkeeping and event handling than blocking
		2450	connects (which involve a single syscall only).
		2451
		2452	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2453	offers similar expressive power as POE and IO::Lambda, using conventional
		2454	Perl syntax. This means that both the echo server and the client are 100%
		2455	non-blocking, further placing it at a disadvantage.
		2456
		2457	As you can see, the AnyEvent + EV combination even beats the
		2458	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2459	backend easily beats IO::Lambda and POE.
		2460
		2461	And even the 100% non-blocking version written using the high-level (and
		2462	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2463	higher level ("unoptimised") abstractions by a large margin, even though
		2464	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
		2465
		2466	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2467	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2468	part of the IO::Lambda distribution and were used without any changes.
		2469
1758		2470
1759	=head1 SIGNALS	2471	=head1 SIGNALS
1760		2472
1761	AnyEvent currently installs handlers for these signals:	2473	AnyEvent currently installs handlers for these signals:
1762		2474
…		…
1765	=item SIGCHLD	2477	=item SIGCHLD
1766		2478
1767	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2479	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1768	emulation for event loops that do not support them natively. Also, some	2480	emulation for event loops that do not support them natively. Also, some
1769	event loops install a similar handler.	2481	event loops install a similar handler.
		2482
		2483	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2484	AnyEvent will reset it to default, to avoid losing child exit statuses.
1770		2485
1771	=item SIGPIPE	2486	=item SIGPIPE
1772		2487
1773	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2488	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1774	when AnyEvent gets loaded.	2489	when AnyEvent gets loaded.
…		…
1786		2501
1787	=back	2502	=back
1788		2503
1789	=cut	2504	=cut
1790		2505
		2506	undef $SIG{CHLD}
		2507	if $SIG{CHLD} eq 'IGNORE';
		2508
1791	$SIG{PIPE} = sub { }	2509	$SIG{PIPE} = sub { }
1792	unless defined $SIG{PIPE};	2510	unless defined $SIG{PIPE};
1793		2511
		2512	=head1 RECOMMENDED/OPTIONAL MODULES
		2513
		2514	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2515	it's built-in modules) are required to use it.
		2516
		2517	That does not mean that AnyEvent won't take advantage of some additional
		2518	modules if they are installed.
		2519
		2520	This section explains which additional modules will be used, and how they
		2521	affect AnyEvent's operation.
		2522
		2523	=over 4
		2524
		2525	=item L<Async::Interrupt>
		2526
		2527	This slightly arcane module is used to implement fast signal handling: To
		2528	my knowledge, there is no way to do completely race-free and quick
		2529	signal handling in pure perl. To ensure that signals still get
		2530	delivered, AnyEvent will start an interval timer to wake up perl (and
		2531	catch the signals) with some delay (default is 10 seconds, look for
		2532	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2533
		2534	If this module is available, then it will be used to implement signal
		2535	catching, which means that signals will not be delayed, and the event loop
		2536	will not be interrupted regularly, which is more efficient (and good for
		2537	battery life on laptops).
		2538
		2539	This affects not just the pure-perl event loop, but also other event loops
		2540	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2541
		2542	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2543	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2544	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2545	does nothing for those backends.
		2546
		2547	=item L<EV>
		2548
		2549	This module isn't really "optional", as it is simply one of the backend
		2550	event loops that AnyEvent can use. However, it is simply the best event
		2551	loop available in terms of features, speed and stability: It supports
		2552	the AnyEvent API optimally, implements all the watcher types in XS, does
		2553	automatic timer adjustments even when no monotonic clock is available,
		2554	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2555	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2556	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2557
		2558	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2559	then this module will do nothing for you.
		2560
		2561	=item L<Guard>
		2562
		2563	The guard module, when used, will be used to implement
		2564	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2565	lot less memory), but otherwise doesn't affect guard operation much. It is
		2566	purely used for performance.
		2567
		2568	=item L<JSON> and L<JSON::XS>
		2569
		2570	One of these modules is required when you want to read or write JSON data
		2571	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2572	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2573
		2574	=item L<Net::SSLeay>
		2575
		2576	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2577	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2578	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2579
		2580	=item L<Time::HiRes>
		2581
		2582	This module is part of perl since release 5.008. It will be used when the
		2583	chosen event library does not come with a timing source on it's own. The
		2584	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2585	try to use a monotonic clock for timing stability.
		2586
		2587	=back
		2588
1794		2589
1795	=head1 FORK	2590	=head1 FORK
1796		2591
1797	Most event libraries are not fork-safe. The ones who are usually are	2592	Most event libraries are not fork-safe. The ones who are usually are
1798	because they rely on inefficient but fork-safe C<select> or C<poll>	2593	because they rely on inefficient but fork-safe C<select> or C<poll> calls
1799	calls. Only L<EV> is fully fork-aware.	2594	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2595	are usually badly thought-out hacks that are incompatible with fork in
		2596	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2597	continue event-processing in both parent and child (or both, if you know
		2598	what you are doing).
		2599
		2600	This means that, in general, you cannot fork and do event processing in
		2601	the child if the event library was initialised before the fork (which
		2602	usually happens when the first AnyEvent watcher is created, or the library
		2603	is loaded).
1800		2604
1801	If you have to fork, you must either do so I<before> creating your first	2605	If you have to fork, you must either do so I<before> creating your first
1802	watcher OR you must not use AnyEvent at all in the child.	2606	watcher OR you must not use AnyEvent at all in the child OR you must do
		2607	something completely out of the scope of AnyEvent.
		2608
		2609	The problem of doing event processing in the parent I<and> the child
		2610	is much more complicated: even for backends that I<are> fork-aware or
		2611	fork-safe, their behaviour is not usually what you want: fork clones all
		2612	watchers, that means all timers, I/O watchers etc. are active in both
		2613	parent and child, which is almost never what you want. USing C<exec>
		2614	to start worker children from some kind of manage rprocess is usually
		2615	preferred, because it is much easier and cleaner, at the expense of having
		2616	to have another binary.
1803		2617
1804		2618
1805	=head1 SECURITY CONSIDERATIONS	2619	=head1 SECURITY CONSIDERATIONS
1806		2620
1807	AnyEvent can be forced to load any event model via	2621	AnyEvent can be forced to load any event model via
…		…
1819	use AnyEvent;	2633	use AnyEvent;
1820		2634
1821	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2635	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1822	be used to probe what backend is used and gain other information (which is	2636	be used to probe what backend is used and gain other information (which is
1823	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2637	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1824	$ENV{PERL_ANYEGENT_STRICT}.	2638	$ENV{PERL_ANYEVENT_STRICT}.
		2639
		2640	Note that AnyEvent will remove I<all> environment variables starting with
		2641	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2642	enabled.
1825		2643
1826		2644
1827	=head1 BUGS	2645	=head1 BUGS
1828		2646
1829	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2647	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1830	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2648	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1831	and check wether the leaks still show up. (Perl 5.10.0 has other annoying	2649	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1832	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as	2650	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1833	pronounced).	2651	pronounced).
1834		2652
1835		2653
1836	=head1 SEE ALSO	2654	=head1 SEE ALSO
1837		2655
…		…
1841	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2659	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1842		2660
1843	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2661	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1844	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2662	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1845	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2663	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1846	L<AnyEvent::Impl::POE>.	2664	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1847		2665
1848	Non-blocking file handles, sockets, TCP clients and	2666	Non-blocking file handles, sockets, TCP clients and
1849	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2667	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1850		2668
1851	Asynchronous DNS: L<AnyEvent::DNS>.	2669	Asynchronous DNS: L<AnyEvent::DNS>.
1852		2670
1853	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2671	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2672	L<Coro::Event>,
1854		2673
1855	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2674	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2675	L<AnyEvent::HTTP>.
1856		2676
1857		2677
1858	=head1 AUTHOR	2678	=head1 AUTHOR
1859		2679
1860	Marc Lehmann <schmorp@schmorp.de>	2680	Marc Lehmann <schmorp@schmorp.de>

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