ViewVC Help

View File | Revision Log | Show Annotations | Download File

/cvs/AnyEvent/lib/AnyEvent.pm

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.176 by root, Wed Aug 20 12:37:21 2008 UTC vs.
Revision 1.263 by root, Wed Jul 29 12:39:21 2009 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
		6	and POE are various supported event loops/environments.
6		7
7	=head1 SYNOPSIS	8	=head1 SYNOPSIS
8		9
9	use AnyEvent;	10	use AnyEvent;
10		11
		12	# file descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { ... });	13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
12		14
		15	# one-shot or repeating timers
13	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
14	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
15		18
16	print AnyEvent->now; # prints current event loop time	19	print AnyEvent->now; # prints current event loop time
17	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
18		21
		22	# POSIX signal
19	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });	23	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
20		24
		25	# child process exit
21	my $w = AnyEvent->child (pid => $pid, cb => sub {	26	my $w = AnyEvent->child (pid => $pid, cb => sub {
22	my ($pid, $status) = @_;	27	my ($pid, $status) = @_;
23	...	28	...
24	});	29	});
		30
		31	# called when event loop idle (if applicable)
		32	my $w = AnyEvent->idle (cb => sub { ... });
25		33
26	my $w = AnyEvent->condvar; # stores whether a condition was flagged	34	my $w = AnyEvent->condvar; # stores whether a condition was flagged
27	$w->send; # wake up current and all future recv's	35	$w->send; # wake up current and all future recv's
28	$w->recv; # enters "main loop" till $condvar gets ->send	36	$w->recv; # enters "main loop" till $condvar gets ->send
29	# use a condvar in callback mode:	37	# use a condvar in callback mode:
…		…
32	=head1 INTRODUCTION/TUTORIAL	40	=head1 INTRODUCTION/TUTORIAL
33		41
34	This manpage is mainly a reference manual. If you are interested	42	This manpage is mainly a reference manual. If you are interested
35	in a tutorial or some gentle introduction, have a look at the	43	in a tutorial or some gentle introduction, have a look at the
36	L<AnyEvent::Intro> manpage.	44	L<AnyEvent::Intro> manpage.
		45
		46	=head1 SUPPORT
		47
		48	There is a mailinglist for discussing all things AnyEvent, and an IRC
		49	channel, too.
		50
		51	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		52	Repository>, at L<http://anyevent.schmorp.de>, for more info.
37		53
38	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	54	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
39		55
40	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	56	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
41	nowadays. So what is different about AnyEvent?	57	nowadays. So what is different about AnyEvent?
…		…
137	These watchers are normal Perl objects with normal Perl lifetime. After	153	These watchers are normal Perl objects with normal Perl lifetime. After
138	creating a watcher it will immediately "watch" for events and invoke the	154	creating a watcher it will immediately "watch" for events and invoke the
139	callback when the event occurs (of course, only when the event model	155	callback when the event occurs (of course, only when the event model
140	is in control).	156	is in control).
141		157
		158	Note that B<callbacks must not permanently change global variables>
		159	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
		160	callbacks must not C<die> >>. The former is good programming practise in
		161	Perl and the latter stems from the fact that exception handling differs
		162	widely between event loops.
		163
142	To disable the watcher you have to destroy it (e.g. by setting the	164	To disable the watcher you have to destroy it (e.g. by setting the
143	variable you store it in to C<undef> or otherwise deleting all references	165	variable you store it in to C<undef> or otherwise deleting all references
144	to it).	166	to it).
145		167
146	All watchers are created by calling a method on the C<AnyEvent> class.	168	All watchers are created by calling a method on the C<AnyEvent> class.
…		…
162	=head2 I/O WATCHERS	184	=head2 I/O WATCHERS
163		185
164	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	186	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
165	with the following mandatory key-value pairs as arguments:	187	with the following mandatory key-value pairs as arguments:
166		188
167	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events	189	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
168	(AnyEvent might or might not keep a reference to this file handle). C<poll>	190	for events (AnyEvent might or might not keep a reference to this file
		191	handle). Note that only file handles pointing to things for which
		192	non-blocking operation makes sense are allowed. This includes sockets,
		193	most character devices, pipes, fifos and so on, but not for example files
		194	or block devices.
		195
169	must be a string that is either C<r> or C<w>, which creates a watcher	196	C<poll> must be a string that is either C<r> or C<w>, which creates a
170	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the	197	watcher waiting for "r"eadable or "w"ritable events, respectively.
		198
171	callback to invoke each time the file handle becomes ready.	199	C<cb> is the callback to invoke each time the file handle becomes ready.
172		200
173	Although the callback might get passed parameters, their value and	201	Although the callback might get passed parameters, their value and
174	presence is undefined and you cannot rely on them. Portable AnyEvent	202	presence is undefined and you cannot rely on them. Portable AnyEvent
175	callbacks cannot use arguments passed to I/O watcher callbacks.	203	callbacks cannot use arguments passed to I/O watcher callbacks.
176		204
…		…
308	In either case, if you care (and in most cases, you don't), then you	336	In either case, if you care (and in most cases, you don't), then you
309	can get whatever behaviour you want with any event loop, by taking the	337	can get whatever behaviour you want with any event loop, by taking the
310	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	338	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
311	account.	339	account.
312		340
		341	=item AnyEvent->now_update
		342
		343	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		344	the current time for each loop iteration (see the discussion of L<<
		345	AnyEvent->now >>, above).
		346
		347	When a callback runs for a long time (or when the process sleeps), then
		348	this "current" time will differ substantially from the real time, which
		349	might affect timers and time-outs.
		350
		351	When this is the case, you can call this method, which will update the
		352	event loop's idea of "current time".
		353
		354	Note that updating the time I<might> cause some events to be handled.
		355
313	=back	356	=back
314		357
315	=head2 SIGNAL WATCHERS	358	=head2 SIGNAL WATCHERS
316		359
317	You can watch for signals using a signal watcher, C<signal> is the signal	360	You can watch for signals using a signal watcher, C<signal> is the signal
…		…
326	invocation, and callback invocation will be synchronous. Synchronous means	369	invocation, and callback invocation will be synchronous. Synchronous means
327	that it might take a while until the signal gets handled by the process,	370	that it might take a while until the signal gets handled by the process,
328	but it is guaranteed not to interrupt any other callbacks.	371	but it is guaranteed not to interrupt any other callbacks.
329		372
330	The main advantage of using these watchers is that you can share a signal	373	The main advantage of using these watchers is that you can share a signal
331	between multiple watchers.	374	between multiple watchers, and AnyEvent will ensure that signals will not
		375	interrupt your program at bad times.
332		376
333	This watcher might use C<%SIG>, so programs overwriting those signals	377	This watcher might use C<%SIG> (depending on the event loop used),
334	directly will likely not work correctly.	378	so programs overwriting those signals directly will likely not work
		379	correctly.
335		380
336	Example: exit on SIGINT	381	Example: exit on SIGINT
337		382
338	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	383	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
339		384
		385	=head3 Signal Races, Delays and Workarounds
		386
		387	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		388	callbacks to signals in a generic way, which is a pity, as you cannot do
		389	race-free signal handling in perl. AnyEvent will try to do it's best, but
		390	in some cases, signals will be delayed. The maximum time a signal might
		391	be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10
		392	seconds). This variable can be changed only before the first signal
		393	watcher is created, and should be left alone otherwise. Higher values
		394	will cause fewer spurious wake-ups, which is better for power and CPU
		395	saving. All these problems can be avoided by installing the optional
		396	L<Async::Interrupt> module. This will not work with inherently broken
		397	event loops such as L<Event> or L<Event::Lib> (and not with L<POE>
		398	currently, as POE does it's own workaround with one-second latency). With
		399	those, you just have to suffer the delays.
		400
340	=head2 CHILD PROCESS WATCHERS	401	=head2 CHILD PROCESS WATCHERS
341		402
342	You can also watch on a child process exit and catch its exit status.	403	You can also watch on a child process exit and catch its exit status.
343		404
344	The child process is specified by the C<pid> argument (if set to C<0>, it	405	The child process is specified by the C<pid> argument (one some backends,
345	watches for any child process exit). The watcher will trigger as often	406	using C<0> watches for any child process exit, on others this will
346	as status change for the child are received. This works by installing a	407	croak). The watcher will be triggered only when the child process has
347	signal handler for C<SIGCHLD>. The callback will be called with the pid	408	finished and an exit status is available, not on any trace events
348	and exit status (as returned by waitpid), so unlike other watcher types,	409	(stopped/continued).
349	you I<can> rely on child watcher callback arguments.	410
		411	The callback will be called with the pid and exit status (as returned by
		412	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		413	callback arguments.
		414
		415	This watcher type works by installing a signal handler for C<SIGCHLD>,
		416	and since it cannot be shared, nothing else should use SIGCHLD or reap
		417	random child processes (waiting for specific child processes, e.g. inside
		418	C<system>, is just fine).
350		419
351	There is a slight catch to child watchers, however: you usually start them	420	There is a slight catch to child watchers, however: you usually start them
352	I<after> the child process was created, and this means the process could	421	I<after> the child process was created, and this means the process could
353	have exited already (and no SIGCHLD will be sent anymore).	422	have exited already (and no SIGCHLD will be sent anymore).
354		423
355	Not all event models handle this correctly (POE doesn't), but even for	424	Not all event models handle this correctly (neither POE nor IO::Async do,
		425	see their AnyEvent::Impl manpages for details), but even for event models
356	event models that I<do> handle this correctly, they usually need to be	426	that I<do> handle this correctly, they usually need to be loaded before
357	loaded before the process exits (i.e. before you fork in the first place).	427	the process exits (i.e. before you fork in the first place). AnyEvent's
		428	pure perl event loop handles all cases correctly regardless of when you
		429	start the watcher.
358		430
359	This means you cannot create a child watcher as the very first thing in an	431	This means you cannot create a child watcher as the very first
360	AnyEvent program, you I<have> to create at least one watcher before you	432	thing in an AnyEvent program, you I<have> to create at least one
361	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	433	watcher before you C<fork> the child (alternatively, you can call
		434	C<AnyEvent::detect>).
		435
		436	As most event loops do not support waiting for child events, they will be
		437	emulated by AnyEvent in most cases, in which the latency and race problems
		438	mentioned in the description of signal watchers apply.
362		439
363	Example: fork a process and wait for it	440	Example: fork a process and wait for it
364		441
365	my $done = AnyEvent->condvar;	442	my $done = AnyEvent->condvar;
366		443
…		…
376	);	453	);
377		454
378	# do something else, then wait for process exit	455	# do something else, then wait for process exit
379	$done->recv;	456	$done->recv;
380		457
		458	=head2 IDLE WATCHERS
		459
		460	Sometimes there is a need to do something, but it is not so important
		461	to do it instantly, but only when there is nothing better to do. This
		462	"nothing better to do" is usually defined to be "no other events need
		463	attention by the event loop".
		464
		465	Idle watchers ideally get invoked when the event loop has nothing
		466	better to do, just before it would block the process to wait for new
		467	events. Instead of blocking, the idle watcher is invoked.
		468
		469	Most event loops unfortunately do not really support idle watchers (only
		470	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		471	will simply call the callback "from time to time".
		472
		473	Example: read lines from STDIN, but only process them when the
		474	program is otherwise idle:
		475
		476	my @lines; # read data
		477	my $idle_w;
		478	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		479	push @lines, scalar <STDIN>;
		480
		481	# start an idle watcher, if not already done
		482	$idle_w ||= AnyEvent->idle (cb => sub {
		483	# handle only one line, when there are lines left
		484	if (my $line = shift @lines) {
		485	print "handled when idle: $line";
		486	} else {
		487	# otherwise disable the idle watcher again
		488	undef $idle_w;
		489	}
		490	});
		491	});
		492
381	=head2 CONDITION VARIABLES	493	=head2 CONDITION VARIABLES
382		494
383	If you are familiar with some event loops you will know that all of them	495	If you are familiar with some event loops you will know that all of them
384	require you to run some blocking "loop", "run" or similar function that	496	require you to run some blocking "loop", "run" or similar function that
385	will actively watch for new events and call your callbacks.	497	will actively watch for new events and call your callbacks.
386		498
387	AnyEvent is different, it expects somebody else to run the event loop and	499	AnyEvent is slightly different: it expects somebody else to run the event
388	will only block when necessary (usually when told by the user).	500	loop and will only block when necessary (usually when told by the user).
389		501
390	The instrument to do that is called a "condition variable", so called	502	The instrument to do that is called a "condition variable", so called
391	because they represent a condition that must become true.	503	because they represent a condition that must become true.
392		504
		505	Now is probably a good time to look at the examples further below.
		506
393	Condition variables can be created by calling the C<< AnyEvent->condvar	507	Condition variables can be created by calling the C<< AnyEvent->condvar
394	>> method, usually without arguments. The only argument pair allowed is	508	>> method, usually without arguments. The only argument pair allowed is
395
396	C<cb>, which specifies a callback to be called when the condition variable	509	C<cb>, which specifies a callback to be called when the condition variable
397	becomes true, with the condition variable as the first argument (but not	510	becomes true, with the condition variable as the first argument (but not
398	the results).	511	the results).
399		512
400	After creation, the condition variable is "false" until it becomes "true"	513	After creation, the condition variable is "false" until it becomes "true"
…		…
405	Condition variables are similar to callbacks, except that you can	518	Condition variables are similar to callbacks, except that you can
406	optionally wait for them. They can also be called merge points - points	519	optionally wait for them. They can also be called merge points - points
407	in time where multiple outstanding events have been processed. And yet	520	in time where multiple outstanding events have been processed. And yet
408	another way to call them is transactions - each condition variable can be	521	another way to call them is transactions - each condition variable can be
409	used to represent a transaction, which finishes at some point and delivers	522	used to represent a transaction, which finishes at some point and delivers
410	a result.	523	a result. And yet some people know them as "futures" - a promise to
		524	compute/deliver something that you can wait for.
411		525
412	Condition variables are very useful to signal that something has finished,	526	Condition variables are very useful to signal that something has finished,
413	for example, if you write a module that does asynchronous http requests,	527	for example, if you write a module that does asynchronous http requests,
414	then a condition variable would be the ideal candidate to signal the	528	then a condition variable would be the ideal candidate to signal the
415	availability of results. The user can either act when the callback is	529	availability of results. The user can either act when the callback is
…		…
449	after => 1,	563	after => 1,
450	cb => sub { $result_ready->send },	564	cb => sub { $result_ready->send },
451	);	565	);
452		566
453	# this "blocks" (while handling events) till the callback	567	# this "blocks" (while handling events) till the callback
454	# calls send	568	# calls -<send
455	$result_ready->recv;	569	$result_ready->recv;
456		570
457	Example: wait for a timer, but take advantage of the fact that	571	Example: wait for a timer, but take advantage of the fact that condition
458	condition variables are also code references.	572	variables are also callable directly.
459		573
460	my $done = AnyEvent->condvar;	574	my $done = AnyEvent->condvar;
461	my $delay = AnyEvent->timer (after => 5, cb => $done);	575	my $delay = AnyEvent->timer (after => 5, cb => $done);
462	$done->recv;	576	$done->recv;
463		577
…		…
469		583
470	...	584	...
471		585
472	my @info = $couchdb->info->recv;	586	my @info = $couchdb->info->recv;
473		587
474	And this is how you would just ste a callback to be called whenever the	588	And this is how you would just set a callback to be called whenever the
475	results are available:	589	results are available:
476		590
477	$couchdb->info->cb (sub {	591	$couchdb->info->cb (sub {
478	my @info = $_[0]->recv;	592	my @info = $_[0]->recv;
479	});	593	});
…		…
497	immediately from within send.	611	immediately from within send.
498		612
499	Any arguments passed to the C<send> call will be returned by all	613	Any arguments passed to the C<send> call will be returned by all
500	future C<< ->recv >> calls.	614	future C<< ->recv >> calls.
501		615
502	Condition variables are overloaded so one can call them directly	616	Condition variables are overloaded so one can call them directly (as if
503	(as a code reference). Calling them directly is the same as calling	617	they were a code reference). Calling them directly is the same as calling
504	C<send>. Note, however, that many C-based event loops do not handle	618	C<send>.
505	overloading, so as tempting as it may be, passing a condition variable
506	instead of a callback does not work. Both the pure perl and EV loops
507	support overloading, however, as well as all functions that use perl to
508	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
509	example).
510		619
511	=item $cv->croak ($error)	620	=item $cv->croak ($error)
512		621
513	Similar to send, but causes all call's to C<< ->recv >> to invoke	622	Similar to send, but causes all call's to C<< ->recv >> to invoke
514	C<Carp::croak> with the given error message/object/scalar.	623	C<Carp::croak> with the given error message/object/scalar.
515		624
516	This can be used to signal any errors to the condition variable	625	This can be used to signal any errors to the condition variable
517	user/consumer.	626	user/consumer. Doing it this way instead of calling C<croak> directly
		627	delays the error detetcion, but has the overwhelmign advantage that it
		628	diagnoses the error at the place where the result is expected, and not
		629	deep in some event clalback without connection to the actual code causing
		630	the problem.
518		631
519	=item $cv->begin ([group callback])	632	=item $cv->begin ([group callback])
520		633
521	=item $cv->end	634	=item $cv->end
522
523	These two methods are EXPERIMENTAL and MIGHT CHANGE.
524		635
525	These two methods can be used to combine many transactions/events into	636	These two methods can be used to combine many transactions/events into
526	one. For example, a function that pings many hosts in parallel might want	637	one. For example, a function that pings many hosts in parallel might want
527	to use a condition variable for the whole process.	638	to use a condition variable for the whole process.
528		639
…		…
530	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	641	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
531	>>, the (last) callback passed to C<begin> will be executed. That callback	642	>>, the (last) callback passed to C<begin> will be executed. That callback
532	is I<supposed> to call C<< ->send >>, but that is not required. If no	643	is I<supposed> to call C<< ->send >>, but that is not required. If no
533	callback was set, C<send> will be called without any arguments.	644	callback was set, C<send> will be called without any arguments.
534		645
535	Let's clarify this with the ping example:	646	You can think of C<< $cv->send >> giving you an OR condition (one call
		647	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		648	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		649
		650	Let's start with a simple example: you have two I/O watchers (for example,
		651	STDOUT and STDERR for a program), and you want to wait for both streams to
		652	close before activating a condvar:
		653
		654	my $cv = AnyEvent->condvar;
		655
		656	$cv->begin; # first watcher
		657	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		658	defined sysread $fh1, my $buf, 4096
		659	or $cv->end;
		660	});
		661
		662	$cv->begin; # second watcher
		663	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		664	defined sysread $fh2, my $buf, 4096
		665	or $cv->end;
		666	});
		667
		668	$cv->recv;
		669
		670	This works because for every event source (EOF on file handle), there is
		671	one call to C<begin>, so the condvar waits for all calls to C<end> before
		672	sending.
		673
		674	The ping example mentioned above is slightly more complicated, as the
		675	there are results to be passwd back, and the number of tasks that are
		676	begung can potentially be zero:
536		677
537	my $cv = AnyEvent->condvar;	678	my $cv = AnyEvent->condvar;
538		679
539	my %result;	680	my %result;
540	$cv->begin (sub { $cv->send (\%result) });	681	$cv->begin (sub { $cv->send (\%result) });
…		…
560	loop, which serves two important purposes: first, it sets the callback	701	loop, which serves two important purposes: first, it sets the callback
561	to be called once the counter reaches C<0>, and second, it ensures that	702	to be called once the counter reaches C<0>, and second, it ensures that
562	C<send> is called even when C<no> hosts are being pinged (the loop	703	C<send> is called even when C<no> hosts are being pinged (the loop
563	doesn't execute once).	704	doesn't execute once).
564		705
565	This is the general pattern when you "fan out" into multiple subrequests:	706	This is the general pattern when you "fan out" into multiple (but
566	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	707	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
567	is called at least once, and then, for each subrequest you start, call	708	the callback and ensure C<end> is called at least once, and then, for each
568	C<begin> and for each subrequest you finish, call C<end>.	709	subrequest you start, call C<begin> and for each subrequest you finish,
		710	call C<end>.
569		711
570	=back	712	=back
571		713
572	=head3 METHODS FOR CONSUMERS	714	=head3 METHODS FOR CONSUMERS
573		715
…		…
589	function will call C<croak>.	731	function will call C<croak>.
590		732
591	In list context, all parameters passed to C<send> will be returned,	733	In list context, all parameters passed to C<send> will be returned,
592	in scalar context only the first one will be returned.	734	in scalar context only the first one will be returned.
593		735
		736	Note that doing a blocking wait in a callback is not supported by any
		737	event loop, that is, recursive invocation of a blocking C<< ->recv
		738	>> is not allowed, and the C<recv> call will C<croak> if such a
		739	condition is detected. This condition can be slightly loosened by using
		740	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		741	any thread that doesn't run the event loop itself.
		742
594	Not all event models support a blocking wait - some die in that case	743	Not all event models support a blocking wait - some die in that case
595	(programs might want to do that to stay interactive), so I<if you are	744	(programs might want to do that to stay interactive), so I<if you are
596	using this from a module, never require a blocking wait>, but let the	745	using this from a module, never require a blocking wait>. Instead, let the
597	caller decide whether the call will block or not (for example, by coupling	746	caller decide whether the call will block or not (for example, by coupling
598	condition variables with some kind of request results and supporting	747	condition variables with some kind of request results and supporting
599	callbacks so the caller knows that getting the result will not block,	748	callbacks so the caller knows that getting the result will not block,
600	while still supporting blocking waits if the caller so desires).	749	while still supporting blocking waits if the caller so desires).
601		750
602	Another reason I<never> to C<< ->recv >> in a module is that you cannot
603	sensibly have two C<< ->recv >>'s in parallel, as that would require
604	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
605	can supply.
606
607	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
608	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
609	versions and also integrates coroutines into AnyEvent, making blocking
610	C<< ->recv >> calls perfectly safe as long as they are done from another
611	coroutine (one that doesn't run the event loop).
612
613	You can ensure that C<< -recv >> never blocks by setting a callback and	751	You can ensure that C<< -recv >> never blocks by setting a callback and
614	only calling C<< ->recv >> from within that callback (or at a later	752	only calling C<< ->recv >> from within that callback (or at a later
615	time). This will work even when the event loop does not support blocking	753	time). This will work even when the event loop does not support blocking
616	waits otherwise.	754	waits otherwise.
617		755
…		…
630	variable itself. Calling C<recv> inside the callback or at any later time	768	variable itself. Calling C<recv> inside the callback or at any later time
631	is guaranteed not to block.	769	is guaranteed not to block.
632		770
633	=back	771	=back
634		772
		773	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		774
		775	The available backend classes are (every class has its own manpage):
		776
		777	=over 4
		778
		779	=item Backends that are autoprobed when no other event loop can be found.
		780
		781	EV is the preferred backend when no other event loop seems to be in
		782	use. If EV is not installed, then AnyEvent will try Event, and, failing
		783	that, will fall back to its own pure-perl implementation, which is
		784	available everywhere as it comes with AnyEvent itself.
		785
		786	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		787	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		788	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		789
		790	=item Backends that are transparently being picked up when they are used.
		791
		792	These will be used when they are currently loaded when the first watcher
		793	is created, in which case it is assumed that the application is using
		794	them. This means that AnyEvent will automatically pick the right backend
		795	when the main program loads an event module before anything starts to
		796	create watchers. Nothing special needs to be done by the main program.
		797
		798	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		799	AnyEvent::Impl::Tk based on Tk, very broken.
		800	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		801	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		802	AnyEvent::Impl::Irssi used when running within irssi.
		803
		804	=item Backends with special needs.
		805
		806	Qt requires the Qt::Application to be instantiated first, but will
		807	otherwise be picked up automatically. As long as the main program
		808	instantiates the application before any AnyEvent watchers are created,
		809	everything should just work.
		810
		811	AnyEvent::Impl::Qt based on Qt.
		812
		813	Support for IO::Async can only be partial, as it is too broken and
		814	architecturally limited to even support the AnyEvent API. It also
		815	is the only event loop that needs the loop to be set explicitly, so
		816	it can only be used by a main program knowing about AnyEvent. See
		817	L<AnyEvent::Impl::Async> for the gory details.
		818
		819	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		820
		821	=item Event loops that are indirectly supported via other backends.
		822
		823	Some event loops can be supported via other modules:
		824
		825	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		826
		827	B<WxWidgets> has no support for watching file handles. However, you can
		828	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		829	polls 20 times per second, which was considered to be too horrible to even
		830	consider for AnyEvent.
		831
		832	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		833	backend, so it can be supported through POE.
		834
		835	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		836	load L<POE> when detecting them, in the hope that POE will pick them up,
		837	in which case everything will be automatic.
		838
		839	=back
		840
635	=head1 GLOBAL VARIABLES AND FUNCTIONS	841	=head1 GLOBAL VARIABLES AND FUNCTIONS
636		842
		843	These are not normally required to use AnyEvent, but can be useful to
		844	write AnyEvent extension modules.
		845
637	=over 4	846	=over 4
638		847
639	=item $AnyEvent::MODEL	848	=item $AnyEvent::MODEL
640		849
641	Contains C<undef> until the first watcher is being created. Then it	850	Contains C<undef> until the first watcher is being created, before the
		851	backend has been autodetected.
		852
642	contains the event model that is being used, which is the name of the	853	Afterwards it contains the event model that is being used, which is the
643	Perl class implementing the model. This class is usually one of the	854	name of the Perl class implementing the model. This class is usually one
644	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	855	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
645	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	856	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
646		857	will be C<urxvt::anyevent>).
647	The known classes so far are:
648
649	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
650	AnyEvent::Impl::Event based on Event, second best choice.
651	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
652	AnyEvent::Impl::Glib based on Glib, third-best choice.
653	AnyEvent::Impl::Tk based on Tk, very bad choice.
654	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
655	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
656	AnyEvent::Impl::POE based on POE, not generic enough for full support.
657
658	There is no support for WxWidgets, as WxWidgets has no support for
659	watching file handles. However, you can use WxWidgets through the
660	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
661	second, which was considered to be too horrible to even consider for
662	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
663	it's adaptor.
664
665	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
666	autodetecting them.
667		858
668	=item AnyEvent::detect	859	=item AnyEvent::detect
669		860
670	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	861	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
671	if necessary. You should only call this function right before you would	862	if necessary. You should only call this function right before you would
672	have created an AnyEvent watcher anyway, that is, as late as possible at	863	have created an AnyEvent watcher anyway, that is, as late as possible at
673	runtime.	864	runtime, and not e.g. while initialising of your module.
		865
		866	If you need to do some initialisation before AnyEvent watchers are
		867	created, use C<post_detect>.
674		868
675	=item $guard = AnyEvent::post_detect { BLOCK }	869	=item $guard = AnyEvent::post_detect { BLOCK }
676		870
677	Arranges for the code block to be executed as soon as the event model is	871	Arranges for the code block to be executed as soon as the event model is
678	autodetected (or immediately if this has already happened).	872	autodetected (or immediately if this has already happened).
679		873
		874	The block will be executed I<after> the actual backend has been detected
		875	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		876	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		877	other initialisations - see the sources of L<AnyEvent::Strict> or
		878	L<AnyEvent::AIO> to see how this is used.
		879
		880	The most common usage is to create some global watchers, without forcing
		881	event module detection too early, for example, L<AnyEvent::AIO> creates
		882	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		883	avoid autodetecting the event module at load time.
		884
680	If called in scalar or list context, then it creates and returns an object	885	If called in scalar or list context, then it creates and returns an object
681	that automatically removes the callback again when it is destroyed. See	886	that automatically removes the callback again when it is destroyed (or
		887	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
682	L<Coro::BDB> for a case where this is useful.	888	a case where this is useful.
		889
		890	Example: Create a watcher for the IO::AIO module and store it in
		891	C<$WATCHER>. Only do so after the event loop is initialised, though.
		892
		893	our WATCHER;
		894
		895	my $guard = AnyEvent::post_detect {
		896	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		897	};
		898
		899	# the ||= is important in case post_detect immediately runs the block,
		900	# as to not clobber the newly-created watcher. assigning both watcher and
		901	# post_detect guard to the same variable has the advantage of users being
		902	# able to just C<undef $WATCHER> if the watcher causes them grief.
		903
		904	$WATCHER ||= $guard;
683		905
684	=item @AnyEvent::post_detect	906	=item @AnyEvent::post_detect
685		907
686	If there are any code references in this array (you can C<push> to it	908	If there are any code references in this array (you can C<push> to it
687	before or after loading AnyEvent), then they will called directly after	909	before or after loading AnyEvent), then they will called directly after
688	the event loop has been chosen.	910	the event loop has been chosen.
689		911
690	You should check C<$AnyEvent::MODEL> before adding to this array, though:	912	You should check C<$AnyEvent::MODEL> before adding to this array, though:
691	if it contains a true value then the event loop has already been detected,	913	if it is defined then the event loop has already been detected, and the
692	and the array will be ignored.	914	array will be ignored.
693		915
694	Best use C<AnyEvent::post_detect { BLOCK }> instead.	916	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		917	it,as it takes care of these details.
		918
		919	This variable is mainly useful for modules that can do something useful
		920	when AnyEvent is used and thus want to know when it is initialised, but do
		921	not need to even load it by default. This array provides the means to hook
		922	into AnyEvent passively, without loading it.
695		923
696	=back	924	=back
697		925
698	=head1 WHAT TO DO IN A MODULE	926	=head1 WHAT TO DO IN A MODULE
699		927
…		…
754		982
755		983
756	=head1 OTHER MODULES	984	=head1 OTHER MODULES
757		985
758	The following is a non-exhaustive list of additional modules that use	986	The following is a non-exhaustive list of additional modules that use
759	AnyEvent and can therefore be mixed easily with other AnyEvent modules	987	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
760	in the same program. Some of the modules come with AnyEvent, some are	988	modules and other event loops in the same program. Some of the modules
761	available via CPAN.	989	come with AnyEvent, most are available via CPAN.
762		990
763	=over 4	991	=over 4
764		992
765	=item L<AnyEvent::Util>	993	=item L<AnyEvent::Util>
766		994
…		…
775		1003
776	=item L<AnyEvent::Handle>	1004	=item L<AnyEvent::Handle>
777		1005
778	Provide read and write buffers, manages watchers for reads and writes,	1006	Provide read and write buffers, manages watchers for reads and writes,
779	supports raw and formatted I/O, I/O queued and fully transparent and	1007	supports raw and formatted I/O, I/O queued and fully transparent and
780	non-blocking SSL/TLS.	1008	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
781		1009
782	=item L<AnyEvent::DNS>	1010	=item L<AnyEvent::DNS>
783		1011
784	Provides rich asynchronous DNS resolver capabilities.	1012	Provides rich asynchronous DNS resolver capabilities.
785		1013
…		…
813		1041
814	=item L<AnyEvent::GPSD>	1042	=item L<AnyEvent::GPSD>
815		1043
816	A non-blocking interface to gpsd, a daemon delivering GPS information.	1044	A non-blocking interface to gpsd, a daemon delivering GPS information.
817		1045
		1046	=item L<AnyEvent::IRC>
		1047
		1048	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1049
		1050	=item L<AnyEvent::XMPP>
		1051
		1052	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1053	Net::XMPP2>.
		1054
818	=item L<AnyEvent::IGS>	1055	=item L<AnyEvent::IGS>
819		1056
820	A non-blocking interface to the Internet Go Server protocol (used by	1057	A non-blocking interface to the Internet Go Server protocol (used by
821	L<App::IGS>).	1058	L<App::IGS>).
822		1059
823	=item L<Net::IRC3>
824
825	AnyEvent based IRC client module family.
826
827	=item L<Net::XMPP2>
828
829	AnyEvent based XMPP (Jabber protocol) module family.
830
831	=item L<Net::FCP>	1060	=item L<Net::FCP>
832		1061
833	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1062	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
834	of AnyEvent.	1063	of AnyEvent.
835		1064
…		…
839		1068
840	=item L<Coro>	1069	=item L<Coro>
841		1070
842	Has special support for AnyEvent via L<Coro::AnyEvent>.	1071	Has special support for AnyEvent via L<Coro::AnyEvent>.
843		1072
844	=item L<IO::Lambda>
845
846	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
847
848	=back	1073	=back
849		1074
850	=cut	1075	=cut
851		1076
852	package AnyEvent;	1077	package AnyEvent;
853		1078
		1079	# basically a tuned-down version of common::sense
		1080	sub common_sense {
854	no warnings;	1081	# no warnings
855	use strict;	1082	${^WARNING_BITS} ^= ${^WARNING_BITS};
		1083	# use strict vars subs
		1084	$^H |= 0x00000600;
		1085	}
856		1086
		1087	BEGIN { AnyEvent::common_sense }
		1088
857	use Carp;	1089	use Carp ();
858		1090
859	our $VERSION = 4.231;	1091	our $VERSION = 4.881;
860	our $MODEL;	1092	our $MODEL;
861		1093
862	our $AUTOLOAD;	1094	our $AUTOLOAD;
863	our @ISA;	1095	our @ISA;
864		1096
865	our @REGISTRY;	1097	our @REGISTRY;
866		1098
867	our $WIN32;	1099	our $WIN32;
868		1100
		1101	our $VERBOSE;
		1102
869	BEGIN {	1103	BEGIN {
870	my $win32 = ! ! ($^O =~ /mswin32/i);	1104	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
871	eval "sub WIN32(){ $win32 }";	1105	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
872	}
873		1106
		1107	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1108	if ${^TAINT};
		1109
874	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1110	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1111
		1112	}
		1113
		1114	our $MAX_SIGNAL_LATENCY = 10;
875		1115
876	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1116	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
877		1117
878	{	1118	{
879	my $idx;	1119	my $idx;
…		…
881	for reverse split /\s*,\s*/,	1121	for reverse split /\s*,\s*/,
882	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1122	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
883	}	1123	}
884		1124
885	my @models = (	1125	my @models = (
886	[EV:: => AnyEvent::Impl::EV::],	1126	[EV:: => AnyEvent::Impl::EV:: , 1],
887	[Event:: => AnyEvent::Impl::Event::],	1127	[Event:: => AnyEvent::Impl::Event::, 1],
888	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1128	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
889	# everything below here will not be autoprobed	1129	# everything below here will not (normally) be autoprobed
890	# as the pureperl backend should work everywhere	1130	# as the pureperl backend should work everywhere
891	# and is usually faster	1131	# and is usually faster
		1132	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1133	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1134	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
892	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1135	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
893	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
894	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
895	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1136	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
896	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1137	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
897	[Wx:: => AnyEvent::Impl::POE::],	1138	[Wx:: => AnyEvent::Impl::POE::],
898	[Prima:: => AnyEvent::Impl::POE::],	1139	[Prima:: => AnyEvent::Impl::POE::],
		1140	# IO::Async is just too broken - we would need workarounds for its
		1141	# byzantine signal and broken child handling, among others.
		1142	# IO::Async is rather hard to detect, as it doesn't have any
		1143	# obvious default class.
		1144	# [0, IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1145	# [0, IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1146	# [0, IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
899	);	1147	);
900		1148
901	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1149	our %method = map +($_ => 1),
		1150	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
902		1151
903	our @post_detect;	1152	our @post_detect;
904		1153
905	sub post_detect(&) {	1154	sub post_detect(&) {
906	my ($cb) = @_;	1155	my ($cb) = @_;
907		1156
908	if ($MODEL) {	1157	if ($MODEL) {
909	$cb->();	1158	$cb->();
910		1159
911	1	1160	undef
912	} else {	1161	} else {
913	push @post_detect, $cb;	1162	push @post_detect, $cb;
914		1163
915	defined wantarray	1164	defined wantarray
916	? bless \$cb, "AnyEvent::Util::PostDetect"	1165	? bless \$cb, "AnyEvent::Util::postdetect"
917	: ()	1166	: ()
918	}	1167	}
919	}	1168	}
920		1169
921	sub AnyEvent::Util::PostDetect::DESTROY {	1170	sub AnyEvent::Util::postdetect::DESTROY {
922	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1171	@post_detect = grep $_ != ${$_[0]}, @post_detect;
923	}	1172	}
924		1173
925	sub detect() {	1174	sub detect() {
926	unless ($MODEL) {	1175	unless ($MODEL) {
927	no strict 'refs';
928	local $SIG{__DIE__};	1176	local $SIG{__DIE__};
929		1177
930	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1178	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
931	my $model = "AnyEvent::Impl::$1";	1179	my $model = "AnyEvent::Impl::$1";
932	if (eval "require $model") {	1180	if (eval "require $model") {
933	$MODEL = $model;	1181	$MODEL = $model;
934	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1182	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
935	} else {	1183	} else {
936	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1184	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
937	}	1185	}
938	}	1186	}
939		1187
940	# check for already loaded models	1188	# check for already loaded models
941	unless ($MODEL) {	1189	unless ($MODEL) {
942	for (@REGISTRY, @models) {	1190	for (@REGISTRY, @models) {
943	my ($package, $model) = @$_;	1191	my ($package, $model) = @$_;
944	if (${"$package\::VERSION"} > 0) {	1192	if (${"$package\::VERSION"} > 0) {
945	if (eval "require $model") {	1193	if (eval "require $model") {
946	$MODEL = $model;	1194	$MODEL = $model;
947	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1195	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
948	last;	1196	last;
949	}	1197	}
950	}	1198	}
951	}	1199	}
952		1200
953	unless ($MODEL) {	1201	unless ($MODEL) {
954	# try to load a model	1202	# try to autoload a model
955
956	for (@REGISTRY, @models) {	1203	for (@REGISTRY, @models) {
957	my ($package, $model) = @$_;	1204	my ($package, $model, $autoload) = @$_;
		1205	if (
		1206	$autoload
958	if (eval "require $package"	1207	and eval "require $package"
959	and ${"$package\::VERSION"} > 0	1208	and ${"$package\::VERSION"} > 0
960	and eval "require $model") {	1209	and eval "require $model"
		1210	) {
961	$MODEL = $model;	1211	$MODEL = $model;
962	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1212	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
963	last;	1213	last;
964	}	1214	}
965	}	1215	}
966		1216
967	$MODEL	1217	$MODEL
968	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1218	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
969	}	1219	}
970	}	1220	}
971		1221
972	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1222	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
973		1223
…		…
983		1233
984	sub AUTOLOAD {	1234	sub AUTOLOAD {
985	(my $func = $AUTOLOAD) =~ s/.*://;	1235	(my $func = $AUTOLOAD) =~ s/.*://;
986		1236
987	$method{$func}	1237	$method{$func}
988	or croak "$func: not a valid method for AnyEvent objects";	1238	or Carp::croak "$func: not a valid method for AnyEvent objects";
989		1239
990	detect unless $MODEL;	1240	detect unless $MODEL;
991		1241
992	my $class = shift;	1242	my $class = shift;
993	$class->$func (@_);	1243	$class->$func (@_);
994	}	1244	}
995		1245
996	# utility function to dup a filehandle. this is used by many backends	1246	# utility function to dup a filehandle. this is used by many backends
997	# to support binding more than one watcher per filehandle (they usually	1247	# to support binding more than one watcher per filehandle (they usually
998	# allow only one watcher per fd, so we dup it to get a different one).	1248	# allow only one watcher per fd, so we dup it to get a different one).
999	sub _dupfh($$$$) {	1249	sub _dupfh($$;$$) {
1000	my ($poll, $fh, $r, $w) = @_;	1250	my ($poll, $fh, $r, $w) = @_;
1001		1251
1002	require Fcntl;
1003
1004	# cygwin requires the fh mode to be matching, unix doesn't	1252	# cygwin requires the fh mode to be matching, unix doesn't
1005	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1253	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1006	: $poll eq "w" ? ($w, ">")
1007	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1008		1254
1009	open my $fh2, "$mode&" . fileno $fh	1255	open my $fh2, $mode, $fh
1010	or die "cannot dup() filehandle: $!";	1256	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1011		1257
1012	# we assume CLOEXEC is already set by perl in all important cases	1258	# we assume CLOEXEC is already set by perl in all important cases
1013		1259
1014	($fh2, $rw)	1260	($fh2, $rw)
1015	}	1261	}
1016		1262
1017	package AnyEvent::Base;	1263	package AnyEvent::Base;
1018		1264
1019	# default implementation for now and time	1265	# default implementations for many methods
1020		1266
1021	use Time::HiRes ();	1267	sub _time {
		1268	# probe for availability of Time::HiRes
		1269	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1270	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
		1271	*_time = \&Time::HiRes::time;
		1272	# if (eval "use POSIX (); (POSIX::times())...
		1273	} else {
		1274	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
		1275	*_time = sub { time }; # epic fail
		1276	}
1022		1277
1023	sub time { Time::HiRes::time }	1278	&_time
1024	sub now { Time::HiRes::time }	1279	}
		1280
		1281	sub time { _time }
		1282	sub now { _time }
		1283	sub now_update { }
1025		1284
1026	# default implementation for ->condvar	1285	# default implementation for ->condvar
1027		1286
1028	sub condvar {	1287	sub condvar {
1029	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1288	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1030	}	1289	}
1031		1290
1032	# default implementation for ->signal	1291	# default implementation for ->signal
1033		1292
1034	our %SIG_CB;	1293	our $HAVE_ASYNC_INTERRUPT;
1035		1294
		1295	sub _have_async_interrupt() {
		1296	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1297	&& eval "use Async::Interrupt 1.0 (); 1")
		1298	unless defined $HAVE_ASYNC_INTERRUPT;
		1299
		1300	$HAVE_ASYNC_INTERRUPT
		1301	}
		1302
		1303	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1304	our (%SIG_ASY, %SIG_ASY_W);
		1305	our ($SIG_COUNT, $SIG_TW);
		1306
		1307	sub _signal_exec {
		1308	$HAVE_ASYNC_INTERRUPT
		1309	? $SIGPIPE_R->drain
		1310	: sysread $SIGPIPE_R, my $dummy, 9;
		1311
		1312	while (%SIG_EV) {
		1313	for (keys %SIG_EV) {
		1314	delete $SIG_EV{$_};
		1315	$_->() for values %{ $SIG_CB{$_} || {} };
		1316	}
		1317	}
		1318	}
		1319
		1320	# install a dummy wakeup watcher to reduce signal catching latency
		1321	sub _sig_add() {
		1322	unless ($SIG_COUNT++) {
		1323	# try to align timer on a full-second boundary, if possible
		1324	my $NOW = AnyEvent->now;
		1325
		1326	$SIG_TW = AnyEvent->timer (
		1327	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1328	interval => $MAX_SIGNAL_LATENCY,
		1329	cb => sub { }, # just for the PERL_ASYNC_CHECK
		1330	);
		1331	}
		1332	}
		1333
		1334	sub _sig_del {
		1335	undef $SIG_TW
		1336	unless --$SIG_COUNT;
		1337	}
		1338
		1339	our %SIGNAME2NUM;
		1340	our @SIGNUM2NAME;
		1341	our $_sig_name_init; $_sig_name_init = sub {
		1342	undef $_sig_name_init;
		1343
		1344	if (_have_async_interrupt) {
		1345	*sig2num = \&Async::Interrupt::sig2num;
		1346	*sig2name = \&Async::Interrupt::sig2name;
		1347	} else {
		1348	require Config;
		1349
		1350	@SIGNAME2NUM{ split ' ', $Config::Config{sig_name} }
		1351	= split ' ', $Config::Config{sig_num};
		1352	@SIGNUM2NAME[values %SIGNAME2NUM] = keys %SIGNAME2NUM;
		1353
		1354	*sig2num = sub($) {
		1355	$_[0] > 0 ? shift : $SIGNAME2NUM{+shift}
		1356	};
		1357	*sig2name = sub ($) {
		1358	$_[0] > 0 ? $SIGNUM2NAME[+shift] : shift
		1359	};
		1360	}
		1361	};
		1362
		1363	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1364	sub sig2name($) { &$_sig_name_init; &sig2name }
		1365
1036	sub signal {	1366	sub _signal {
1037	my (undef, %arg) = @_;	1367	my (undef, %arg) = @_;
1038		1368
1039	my $signal = uc $arg{signal}	1369	my $signal = uc $arg{signal}
1040	or Carp::croak "required option 'signal' is missing";	1370	or Carp::croak "required option 'signal' is missing";
1041		1371
		1372	if ($HAVE_ASYNC_INTERRUPT) {
		1373	# async::interrupt
		1374
		1375	$signal = sig2num $signal;
1042	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1376	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1377
		1378	$SIG_ASY{$signal} ||= new Async::Interrupt
		1379	cb => sub { undef $SIG_EV{$signal} },
		1380	signal => $signal,
		1381	pipe => [$SIGPIPE_R->filenos],
		1382	pipe_autodrain => 0,
		1383	;
		1384
		1385	} else {
		1386	# pure perl
		1387
		1388	# AE::Util has been loaded in signal
		1389	$signal = sig2name $signal;
		1390	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1391
1043	$SIG{$signal} ||= sub {	1392	$SIG{$signal} ||= sub {
1044	$_->() for values %{ $SIG_CB{$signal} || {} };	1393	local $!;
		1394	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1395	undef $SIG_EV{$signal};
		1396	};
		1397
		1398	# can't do signal processing without introducing races in pure perl,
		1399	# so limit the signal latency.
		1400	_sig_add;
1045	};	1401	}
1046		1402
1047	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1403	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1048	}	1404	}
1049		1405
		1406	sub signal {
		1407	# probe for availability of Async::Interrupt
		1408	if (_have_async_interrupt) {
		1409	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
		1410
		1411	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1412	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
		1413
		1414	} else {
		1415	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1416
		1417	require Fcntl;
		1418
		1419	if (AnyEvent::WIN32) {
		1420	require AnyEvent::Util;
		1421
		1422	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1423	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1424	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1425	} else {
		1426	pipe $SIGPIPE_R, $SIGPIPE_W;
		1427	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1428	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1429
		1430	# not strictly required, as $^F is normally 2, but let's make sure...
		1431	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1432	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1433	}
		1434
		1435	$SIGPIPE_R
		1436	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1437
		1438	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1439	}
		1440
		1441	*signal = \&_signal;
		1442	&signal
		1443	}
		1444
1050	sub AnyEvent::Base::Signal::DESTROY {	1445	sub AnyEvent::Base::signal::DESTROY {
1051	my ($signal, $cb) = @{$_[0]};	1446	my ($signal, $cb) = @{$_[0]};
1052		1447
		1448	_sig_del;
		1449
1053	delete $SIG_CB{$signal}{$cb};	1450	delete $SIG_CB{$signal}{$cb};
1054		1451
		1452	$HAVE_ASYNC_INTERRUPT
		1453	? delete $SIG_ASY{$signal}
		1454	: # delete doesn't work with older perls - they then
		1455	# print weird messages, or just unconditionally exit
		1456	# instead of getting the default action.
		1457	undef $SIG{$signal}
1055	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };	1458	unless keys %{ $SIG_CB{$signal} };
1056	}	1459	}
1057		1460
1058	# default implementation for ->child	1461	# default implementation for ->child
1059		1462
1060	our %PID_CB;	1463	our %PID_CB;
1061	our $CHLD_W;	1464	our $CHLD_W;
1062	our $CHLD_DELAY_W;	1465	our $CHLD_DELAY_W;
1063	our $PID_IDLE;
1064	our $WNOHANG;	1466	our $WNOHANG;
1065		1467
1066	sub _child_wait {	1468	sub _emit_childstatus($$) {
1067	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1469	my (undef, $rpid, $rstatus) = @_;
		1470
		1471	$_->($rpid, $rstatus)
1068	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1472	for values %{ $PID_CB{$rpid} || {} },
1069	(values %{ $PID_CB{0} || {} });	1473	values %{ $PID_CB{0} || {} };
1070	}
1071
1072	undef $PID_IDLE;
1073	}	1474	}
1074		1475
1075	sub _sigchld {	1476	sub _sigchld {
1076	# make sure we deliver these changes "synchronous" with the event loop.	1477	my $pid;
1077	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {	1478
1078	undef $CHLD_DELAY_W;	1479	AnyEvent->_emit_childstatus ($pid, $?)
1079	&_child_wait;	1480	while ($pid = waitpid -1, $WNOHANG) > 0;
1080	});
1081	}	1481	}
1082		1482
1083	sub child {	1483	sub child {
1084	my (undef, %arg) = @_;	1484	my (undef, %arg) = @_;
1085		1485
1086	defined (my $pid = $arg{pid} + 0)	1486	defined (my $pid = $arg{pid} + 0)
1087	or Carp::croak "required option 'pid' is missing";	1487	or Carp::croak "required option 'pid' is missing";
1088		1488
1089	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1489	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1090		1490
1091	unless ($WNOHANG) {	1491	# WNOHANG is almost cetrainly 1 everywhere
		1492	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1493	? 1
1092	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1494	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1093	}
1094		1495
1095	unless ($CHLD_W) {	1496	unless ($CHLD_W) {
1096	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1497	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1097	# child could be a zombie already, so make at least one round	1498	# child could be a zombie already, so make at least one round
1098	&_sigchld;	1499	&_sigchld;
1099	}	1500	}
1100		1501
1101	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1502	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1102	}	1503	}
1103		1504
1104	sub AnyEvent::Base::Child::DESTROY {	1505	sub AnyEvent::Base::child::DESTROY {
1105	my ($pid, $cb) = @{$_[0]};	1506	my ($pid, $cb) = @{$_[0]};
1106		1507
1107	delete $PID_CB{$pid}{$cb};	1508	delete $PID_CB{$pid}{$cb};
1108	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1509	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1109		1510
1110	undef $CHLD_W unless keys %PID_CB;	1511	undef $CHLD_W unless keys %PID_CB;
1111	}	1512	}
1112		1513
		1514	# idle emulation is done by simply using a timer, regardless
		1515	# of whether the process is idle or not, and not letting
		1516	# the callback use more than 50% of the time.
		1517	sub idle {
		1518	my (undef, %arg) = @_;
		1519
		1520	my ($cb, $w, $rcb) = $arg{cb};
		1521
		1522	$rcb = sub {
		1523	if ($cb) {
		1524	$w = _time;
		1525	&$cb;
		1526	$w = _time - $w;
		1527
		1528	# never use more then 50% of the time for the idle watcher,
		1529	# within some limits
		1530	$w = 0.0001 if $w < 0.0001;
		1531	$w = 5 if $w > 5;
		1532
		1533	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1534	} else {
		1535	# clean up...
		1536	undef $w;
		1537	undef $rcb;
		1538	}
		1539	};
		1540
		1541	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1542
		1543	bless \\$cb, "AnyEvent::Base::idle"
		1544	}
		1545
		1546	sub AnyEvent::Base::idle::DESTROY {
		1547	undef $${$_[0]};
		1548	}
		1549
1113	package AnyEvent::CondVar;	1550	package AnyEvent::CondVar;
1114		1551
1115	our @ISA = AnyEvent::CondVar::Base::;	1552	our @ISA = AnyEvent::CondVar::Base::;
1116		1553
1117	package AnyEvent::CondVar::Base;	1554	package AnyEvent::CondVar::Base;
1118		1555
1119	use overload	1556	#use overload
1120	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1557	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1121	fallback => 1;	1558	# fallback => 1;
		1559
		1560	# save 300+ kilobytes by dirtily hardcoding overloading
		1561	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1562	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1563	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1564	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1565
		1566	our $WAITING;
1122		1567
1123	sub _send {	1568	sub _send {
1124	# nop	1569	# nop
1125	}	1570	}
1126		1571
…		…
1139	sub ready {	1584	sub ready {
1140	$_[0]{_ae_sent}	1585	$_[0]{_ae_sent}
1141	}	1586	}
1142		1587
1143	sub _wait {	1588	sub _wait {
		1589	$WAITING
		1590	and !$_[0]{_ae_sent}
		1591	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1592
		1593	local $WAITING = 1;
1144	AnyEvent->one_event while !$_[0]{_ae_sent};	1594	AnyEvent->one_event while !$_[0]{_ae_sent};
1145	}	1595	}
1146		1596
1147	sub recv {	1597	sub recv {
1148	$_[0]->_wait;	1598	$_[0]->_wait;
…		…
1167	}	1617	}
1168		1618
1169	# undocumented/compatibility with pre-3.4	1619	# undocumented/compatibility with pre-3.4
1170	*broadcast = \&send;	1620	*broadcast = \&send;
1171	*wait = \&_wait;	1621	*wait = \&_wait;
		1622
		1623	=head1 ERROR AND EXCEPTION HANDLING
		1624
		1625	In general, AnyEvent does not do any error handling - it relies on the
		1626	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1627	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1628	checking of all AnyEvent methods, however, which is highly useful during
		1629	development.
		1630
		1631	As for exception handling (i.e. runtime errors and exceptions thrown while
		1632	executing a callback), this is not only highly event-loop specific, but
		1633	also not in any way wrapped by this module, as this is the job of the main
		1634	program.
		1635
		1636	The pure perl event loop simply re-throws the exception (usually
		1637	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1638	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1639	so on.
		1640
		1641	=head1 ENVIRONMENT VARIABLES
		1642
		1643	The following environment variables are used by this module or its
		1644	submodules.
		1645
		1646	Note that AnyEvent will remove I<all> environment variables starting with
		1647	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1648	enabled.
		1649
		1650	=over 4
		1651
		1652	=item C<PERL_ANYEVENT_VERBOSE>
		1653
		1654	By default, AnyEvent will be completely silent except in fatal
		1655	conditions. You can set this environment variable to make AnyEvent more
		1656	talkative.
		1657
		1658	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1659	conditions, such as not being able to load the event model specified by
		1660	C<PERL_ANYEVENT_MODEL>.
		1661
		1662	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1663	model it chooses.
		1664
		1665	When set to C<8> or higher, then AnyEvent will report extra information on
		1666	which optional modules it loads and how it implements certain features.
		1667
		1668	=item C<PERL_ANYEVENT_STRICT>
		1669
		1670	AnyEvent does not do much argument checking by default, as thorough
		1671	argument checking is very costly. Setting this variable to a true value
		1672	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1673	check the arguments passed to most method calls. If it finds any problems,
		1674	it will croak.
		1675
		1676	In other words, enables "strict" mode.
		1677
		1678	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
		1679	>>, it is definitely recommended to keep it off in production. Keeping
		1680	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1681	can be very useful, however.
		1682
		1683	=item C<PERL_ANYEVENT_MODEL>
		1684
		1685	This can be used to specify the event model to be used by AnyEvent, before
		1686	auto detection and -probing kicks in. It must be a string consisting
		1687	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1688	and the resulting module name is loaded and if the load was successful,
		1689	used as event model. If it fails to load AnyEvent will proceed with
		1690	auto detection and -probing.
		1691
		1692	This functionality might change in future versions.
		1693
		1694	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1695	could start your program like this:
		1696
		1697	PERL_ANYEVENT_MODEL=Perl perl ...
		1698
		1699	=item C<PERL_ANYEVENT_PROTOCOLS>
		1700
		1701	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1702	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1703	of auto probing).
		1704
		1705	Must be set to a comma-separated list of protocols or address families,
		1706	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1707	used, and preference will be given to protocols mentioned earlier in the
		1708	list.
		1709
		1710	This variable can effectively be used for denial-of-service attacks
		1711	against local programs (e.g. when setuid), although the impact is likely
		1712	small, as the program has to handle conenction and other failures anyways.
		1713
		1714	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1715	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1716	- only support IPv4, never try to resolve or contact IPv6
		1717	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1718	IPv6, but prefer IPv6 over IPv4.
		1719
		1720	=item C<PERL_ANYEVENT_EDNS0>
		1721
		1722	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1723	for DNS. This extension is generally useful to reduce DNS traffic, but
		1724	some (broken) firewalls drop such DNS packets, which is why it is off by
		1725	default.
		1726
		1727	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1728	EDNS0 in its DNS requests.
		1729
		1730	=item C<PERL_ANYEVENT_MAX_FORKS>
		1731
		1732	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1733	will create in parallel.
		1734
		1735	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1736
		1737	The default value for the C<max_outstanding> parameter for the default DNS
		1738	resolver - this is the maximum number of parallel DNS requests that are
		1739	sent to the DNS server.
		1740
		1741	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1742
		1743	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1744	configuration) in the default resolver. When set to the empty string, no
		1745	default config will be used.
		1746
		1747	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1748
		1749	When neither C<ca_file> nor C<ca_path> was specified during
		1750	L<AnyEvent::TLS> context creation, and either of these environment
		1751	variables exist, they will be used to specify CA certificate locations
		1752	instead of a system-dependent default.
		1753
		1754	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1755
		1756	When these are set to C<1>, then the respective modules are not
		1757	loaded. Mostly good for testing AnyEvent itself.
		1758
		1759	=back
1172		1760
1173	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1761	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1174		1762
1175	This is an advanced topic that you do not normally need to use AnyEvent in	1763	This is an advanced topic that you do not normally need to use AnyEvent in
1176	a module. This section is only of use to event loop authors who want to	1764	a module. This section is only of use to event loop authors who want to
…		…
1210		1798
1211	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1799	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1212	condition variables: code blocking while waiting for a condition will	1800	condition variables: code blocking while waiting for a condition will
1213	C<die>. This still works with most modules/usages, and blocking calls must	1801	C<die>. This still works with most modules/usages, and blocking calls must
1214	not be done in an interactive application, so it makes sense.	1802	not be done in an interactive application, so it makes sense.
1215
1216	=head1 ENVIRONMENT VARIABLES
1217
1218	The following environment variables are used by this module:
1219
1220	=over 4
1221
1222	=item C<PERL_ANYEVENT_VERBOSE>
1223
1224	By default, AnyEvent will be completely silent except in fatal
1225	conditions. You can set this environment variable to make AnyEvent more
1226	talkative.
1227
1228	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1229	conditions, such as not being able to load the event model specified by
1230	C<PERL_ANYEVENT_MODEL>.
1231
1232	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1233	model it chooses.
1234
1235	=item C<PERL_ANYEVENT_STRICT>
1236
1237	AnyEvent does not do much argument checking by default, as thorough
1238	argument checking is very costly. Setting this variable to a true value
1239	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1240	check the arguments passed to most method calls. If it finds any problems
1241	it will croak.
1242
1243	In other words, enables "strict" mode.
1244
1245	Unlike C<use strict> it is definitely recommended ot keep it off in
1246	production.
1247
1248	=item C<PERL_ANYEVENT_MODEL>
1249
1250	This can be used to specify the event model to be used by AnyEvent, before
1251	auto detection and -probing kicks in. It must be a string consisting
1252	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1253	and the resulting module name is loaded and if the load was successful,
1254	used as event model. If it fails to load AnyEvent will proceed with
1255	auto detection and -probing.
1256
1257	This functionality might change in future versions.
1258
1259	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1260	could start your program like this:
1261
1262	PERL_ANYEVENT_MODEL=Perl perl ...
1263
1264	=item C<PERL_ANYEVENT_PROTOCOLS>
1265
1266	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1267	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1268	of auto probing).
1269
1270	Must be set to a comma-separated list of protocols or address families,
1271	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1272	used, and preference will be given to protocols mentioned earlier in the
1273	list.
1274
1275	This variable can effectively be used for denial-of-service attacks
1276	against local programs (e.g. when setuid), although the impact is likely
1277	small, as the program has to handle connection errors already-
1278
1279	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1280	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1281	- only support IPv4, never try to resolve or contact IPv6
1282	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1283	IPv6, but prefer IPv6 over IPv4.
1284
1285	=item C<PERL_ANYEVENT_EDNS0>
1286
1287	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1288	for DNS. This extension is generally useful to reduce DNS traffic, but
1289	some (broken) firewalls drop such DNS packets, which is why it is off by
1290	default.
1291
1292	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1293	EDNS0 in its DNS requests.
1294
1295	=item C<PERL_ANYEVENT_MAX_FORKS>
1296
1297	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1298	will create in parallel.
1299
1300	=back
1301		1803
1302	=head1 EXAMPLE PROGRAM	1804	=head1 EXAMPLE PROGRAM
1303		1805
1304	The following program uses an I/O watcher to read data from STDIN, a timer	1806	The following program uses an I/O watcher to read data from STDIN, a timer
1305	to display a message once per second, and a condition variable to quit the	1807	to display a message once per second, and a condition variable to quit the
…		…
1499	watcher.	2001	watcher.
1500		2002
1501	=head3 Results	2003	=head3 Results
1502		2004
1503	name watchers bytes create invoke destroy comment	2005	name watchers bytes create invoke destroy comment
1504	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	2006	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1505	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	2007	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1506	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	2008	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1507	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	2009	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1508	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	2010	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1509	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	2011	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		2012	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		2013	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1510	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	2014	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1511	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	2015	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1512	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	2016	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1513	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	2017	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1514		2018
1515	=head3 Discussion	2019	=head3 Discussion
1516		2020
1517	The benchmark does I<not> measure scalability of the event loop very	2021	The benchmark does I<not> measure scalability of the event loop very
1518	well. For example, a select-based event loop (such as the pure perl one)	2022	well. For example, a select-based event loop (such as the pure perl one)
…		…
1543	performance becomes really bad with lots of file descriptors (and few of	2047	performance becomes really bad with lots of file descriptors (and few of
1544	them active), of course, but this was not subject of this benchmark.	2048	them active), of course, but this was not subject of this benchmark.
1545		2049
1546	The C<Event> module has a relatively high setup and callback invocation	2050	The C<Event> module has a relatively high setup and callback invocation
1547	cost, but overall scores in on the third place.	2051	cost, but overall scores in on the third place.
		2052
		2053	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2054	when using its pure perl backend.
1548		2055
1549	C<Glib>'s memory usage is quite a bit higher, but it features a	2056	C<Glib>'s memory usage is quite a bit higher, but it features a
1550	faster callback invocation and overall ends up in the same class as	2057	faster callback invocation and overall ends up in the same class as
1551	C<Event>. However, Glib scales extremely badly, doubling the number of	2058	C<Event>. However, Glib scales extremely badly, doubling the number of
1552	watchers increases the processing time by more than a factor of four,	2059	watchers increases the processing time by more than a factor of four,
…		…
1630	it to another server. This includes deleting the old timeout and creating	2137	it to another server. This includes deleting the old timeout and creating
1631	a new one that moves the timeout into the future.	2138	a new one that moves the timeout into the future.
1632		2139
1633	=head3 Results	2140	=head3 Results
1634		2141
1635	name sockets create request	2142	name sockets create request
1636	EV 20000 69.01 11.16	2143	EV 20000 69.01 11.16
1637	Perl 20000 73.32 35.87	2144	Perl 20000 73.32 35.87
		2145	IOAsync 20000 157.00 98.14 epoll
		2146	IOAsync 20000 159.31 616.06 poll
1638	Event 20000 212.62 257.32	2147	Event 20000 212.62 257.32
1639	Glib 20000 651.16 1896.30	2148	Glib 20000 651.16 1896.30
1640	POE 20000 349.67 12317.24 uses POE::Loop::Event	2149	POE 20000 349.67 12317.24 uses POE::Loop::Event
1641		2150
1642	=head3 Discussion	2151	=head3 Discussion
1643		2152
1644	This benchmark I<does> measure scalability and overall performance of the	2153	This benchmark I<does> measure scalability and overall performance of the
1645	particular event loop.	2154	particular event loop.
…		…
1647	EV is again fastest. Since it is using epoll on my system, the setup time	2156	EV is again fastest. Since it is using epoll on my system, the setup time
1648	is relatively high, though.	2157	is relatively high, though.
1649		2158
1650	Perl surprisingly comes second. It is much faster than the C-based event	2159	Perl surprisingly comes second. It is much faster than the C-based event
1651	loops Event and Glib.	2160	loops Event and Glib.
		2161
		2162	IO::Async performs very well when using its epoll backend, and still quite
		2163	good compared to Glib when using its pure perl backend.
1652		2164
1653	Event suffers from high setup time as well (look at its code and you will	2165	Event suffers from high setup time as well (look at its code and you will
1654	understand why). Callback invocation also has a high overhead compared to	2166	understand why). Callback invocation also has a high overhead compared to
1655	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2167	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1656	uses select or poll in basically all documented configurations.	2168	uses select or poll in basically all documented configurations.
…		…
1719	=item * C-based event loops perform very well with small number of	2231	=item * C-based event loops perform very well with small number of
1720	watchers, as the management overhead dominates.	2232	watchers, as the management overhead dominates.
1721		2233
1722	=back	2234	=back
1723		2235
		2236	=head2 THE IO::Lambda BENCHMARK
		2237
		2238	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2239	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2240	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2241	shouldn't come as a surprise to anybody). As such, the benchmark is
		2242	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2243	very optimal. But how would AnyEvent compare when used without the extra
		2244	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2245
		2246	The benchmark itself creates an echo-server, and then, for 500 times,
		2247	connects to the echo server, sends a line, waits for the reply, and then
		2248	creates the next connection. This is a rather bad benchmark, as it doesn't
		2249	test the efficiency of the framework or much non-blocking I/O, but it is a
		2250	benchmark nevertheless.
		2251
		2252	name runtime
		2253	Lambda/select 0.330 sec
		2254	+ optimized 0.122 sec
		2255	Lambda/AnyEvent 0.327 sec
		2256	+ optimized 0.138 sec
		2257	Raw sockets/select 0.077 sec
		2258	POE/select, components 0.662 sec
		2259	POE/select, raw sockets 0.226 sec
		2260	POE/select, optimized 0.404 sec
		2261
		2262	AnyEvent/select/nb 0.085 sec
		2263	AnyEvent/EV/nb 0.068 sec
		2264	+state machine 0.134 sec
		2265
		2266	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2267	benchmarks actually make blocking connects and use 100% blocking I/O,
		2268	defeating the purpose of an event-based solution. All of the newly
		2269	written AnyEvent benchmarks use 100% non-blocking connects (using
		2270	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2271	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2272	generally require a lot more bookkeeping and event handling than blocking
		2273	connects (which involve a single syscall only).
		2274
		2275	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2276	offers similar expressive power as POE and IO::Lambda, using conventional
		2277	Perl syntax. This means that both the echo server and the client are 100%
		2278	non-blocking, further placing it at a disadvantage.
		2279
		2280	As you can see, the AnyEvent + EV combination even beats the
		2281	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2282	backend easily beats IO::Lambda and POE.
		2283
		2284	And even the 100% non-blocking version written using the high-level (and
		2285	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2286	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2287	in a non-blocking way.
		2288
		2289	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2290	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2291	part of the IO::lambda distribution and were used without any changes.
		2292
		2293
		2294	=head1 SIGNALS
		2295
		2296	AnyEvent currently installs handlers for these signals:
		2297
		2298	=over 4
		2299
		2300	=item SIGCHLD
		2301
		2302	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		2303	emulation for event loops that do not support them natively. Also, some
		2304	event loops install a similar handler.
		2305
		2306	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2307	AnyEvent will reset it to default, to avoid losing child exit statuses.
		2308
		2309	=item SIGPIPE
		2310
		2311	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		2312	when AnyEvent gets loaded.
		2313
		2314	The rationale for this is that AnyEvent users usually do not really depend
		2315	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		2316	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		2317	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		2318	some random socket.
		2319
		2320	The rationale for installing a no-op handler as opposed to ignoring it is
		2321	that this way, the handler will be restored to defaults on exec.
		2322
		2323	Feel free to install your own handler, or reset it to defaults.
		2324
		2325	=back
		2326
		2327	=cut
		2328
		2329	undef $SIG{CHLD}
		2330	if $SIG{CHLD} eq 'IGNORE';
		2331
		2332	$SIG{PIPE} = sub { }
		2333	unless defined $SIG{PIPE};
		2334
		2335	=head1 RECOMMENDED/OPTIONAL MODULES
		2336
		2337	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2338	it's built-in modules) are required to use it.
		2339
		2340	That does not mean that AnyEvent won't take advantage of some additional
		2341	modules if they are installed.
		2342
		2343	This section epxlains which additional modules will be used, and how they
		2344	affect AnyEvent's operetion.
		2345
		2346	=over 4
		2347
		2348	=item L<Async::Interrupt>
		2349
		2350	This slightly arcane module is used to implement fast signal handling: To
		2351	my knowledge, there is no way to do completely race-free and quick
		2352	signal handling in pure perl. To ensure that signals still get
		2353	delivered, AnyEvent will start an interval timer to wake up perl (and
		2354	catch the signals) with some delay (default is 10 seconds, look for
		2355	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2356
		2357	If this module is available, then it will be used to implement signal
		2358	catching, which means that signals will not be delayed, and the event loop
		2359	will not be interrupted regularly, which is more efficient (And good for
		2360	battery life on laptops).
		2361
		2362	This affects not just the pure-perl event loop, but also other event loops
		2363	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2364
		2365	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2366	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2367	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2368	does nothing for those backends.
		2369
		2370	=item L<EV>
		2371
		2372	This module isn't really "optional", as it is simply one of the backend
		2373	event loops that AnyEvent can use. However, it is simply the best event
		2374	loop available in terms of features, speed and stability: It supports
		2375	the AnyEvent API optimally, implements all the watcher types in XS, does
		2376	automatic timer adjustments even when no monotonic clock is available,
		2377	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2378	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2379	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2380
		2381	=item L<Guard>
		2382
		2383	The guard module, when used, will be used to implement
		2384	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2385	lot less memory), but otherwise doesn't affect guard operation much. It is
		2386	purely used for performance.
		2387
		2388	=item L<JSON> and L<JSON::XS>
		2389
		2390	This module is required when you want to read or write JSON data via
		2391	L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2392	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2393
		2394	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2395	installed.
		2396
		2397	=item L<Net::SSLeay>
		2398
		2399	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2400	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2401	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2402
		2403	=item L<Time::HiRes>
		2404
		2405	This module is part of perl since release 5.008. It will be used when the
		2406	chosen event library does not come with a timing source on it's own. The
		2407	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2408	try to use a monotonic clock for timing stability.
		2409
		2410	=back
		2411
1724		2412
1725	=head1 FORK	2413	=head1 FORK
1726		2414
1727	Most event libraries are not fork-safe. The ones who are usually are	2415	Most event libraries are not fork-safe. The ones who are usually are
1728	because they rely on inefficient but fork-safe C<select> or C<poll>	2416	because they rely on inefficient but fork-safe C<select> or C<poll>
1729	calls. Only L<EV> is fully fork-aware.	2417	calls. Only L<EV> is fully fork-aware.
1730		2418
1731	If you have to fork, you must either do so I<before> creating your first	2419	If you have to fork, you must either do so I<before> creating your first
1732	watcher OR you must not use AnyEvent at all in the child.	2420	watcher OR you must not use AnyEvent at all in the child OR you must do
		2421	something completely out of the scope of AnyEvent.
1733		2422
1734		2423
1735	=head1 SECURITY CONSIDERATIONS	2424	=head1 SECURITY CONSIDERATIONS
1736		2425
1737	AnyEvent can be forced to load any event model via	2426	AnyEvent can be forced to load any event model via
…		…
1749	use AnyEvent;	2438	use AnyEvent;
1750		2439
1751	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2440	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1752	be used to probe what backend is used and gain other information (which is	2441	be used to probe what backend is used and gain other information (which is
1753	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2442	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1754	$ENV{PERL_ANYEGENT_STRICT}.	2443	$ENV{PERL_ANYEVENT_STRICT}.
		2444
		2445	Note that AnyEvent will remove I<all> environment variables starting with
		2446	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2447	enabled.
1755		2448
1756		2449
1757	=head1 BUGS	2450	=head1 BUGS
1758		2451
1759	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2452	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1760	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2453	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1761	and check wether the leaks still show up. (Perl 5.10.0 has other annoying	2454	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1762	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as	2455	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1763	pronounced).	2456	pronounced).
1764		2457
1765		2458
1766	=head1 SEE ALSO	2459	=head1 SEE ALSO
1767		2460
…		…
1771	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2464	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1772		2465
1773	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2466	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1774	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2467	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1775	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2468	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1776	L<AnyEvent::Impl::POE>.	2469	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1777		2470
1778	Non-blocking file handles, sockets, TCP clients and	2471	Non-blocking file handles, sockets, TCP clients and
1779	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2472	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1780		2473
1781	Asynchronous DNS: L<AnyEvent::DNS>.	2474	Asynchronous DNS: L<AnyEvent::DNS>.
1782		2475
1783	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2476	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2477	L<Coro::Event>,
1784		2478
1785	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2479	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2480	L<AnyEvent::HTTP>.
1786		2481
1787		2482
1788	=head1 AUTHOR	2483	=head1 AUTHOR
1789		2484
1790	Marc Lehmann <schmorp@schmorp.de>	2485	Marc Lehmann <schmorp@schmorp.de>

Diff Legend

–	Removed lines
+	Added lines
<	Changed lines
>	Changed lines