[ViewVC] Diff of: cvs/AnyEvent/lib/AnyEvent.pm

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.170 by root, Wed Jul 9 11:53:40 2008 UTC vs.
Revision 1.232 by root, Thu Jul 9 01:08:22 2009 UTC

…		…
1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - provide framework for multiple event loops
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported
		6	event loops.
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 { ... });
		14
		15	# one-shot or repeating timers
		16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
		17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
		18
		19	print AnyEvent->now; # prints current event loop time
		20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
		21
		22	# POSIX signal
		23	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
		24
		25	# child process exit
		26	my $w = AnyEvent->child (pid => $pid, cb => sub {
		27	my ($pid, $status) = @_;
12	...	28	...
13	});	29	});
14		30
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	31	# called when event loop idle (if applicable)
16	...	32	my $w = AnyEvent->idle (cb => sub { ... });
17	});
18		33
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	34	my $w = AnyEvent->condvar; # stores whether a condition was flagged
20	$w->send; # wake up current and all future recv's	35	$w->send; # wake up current and all future recv's
21	$w->recv; # enters "main loop" till $condvar gets ->send	36	$w->recv; # enters "main loop" till $condvar gets ->send
		37	# use a condvar in callback mode:
		38	$w->cb (sub { $_[0]->recv });
22		39
23	=head1 INTRODUCTION/TUTORIAL	40	=head1 INTRODUCTION/TUTORIAL
24		41
25	This manpage is mainly a reference manual. If you are interested	42	This manpage is mainly a reference manual. If you are interested
26	in a tutorial or some gentle introduction, have a look at the	43	in a tutorial or some gentle introduction, have a look at the
128	These watchers are normal Perl objects with normal Perl lifetime. After	145	These watchers are normal Perl objects with normal Perl lifetime. After
129	creating a watcher it will immediately "watch" for events and invoke the	146	creating a watcher it will immediately "watch" for events and invoke the
130	callback when the event occurs (of course, only when the event model	147	callback when the event occurs (of course, only when the event model
131	is in control).	148	is in control).
132		149
		150	Note that B<callbacks must not permanently change global variables>
		151	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
		152	callbacks must not C<die> >>. The former is good programming practise in
		153	Perl and the latter stems from the fact that exception handling differs
		154	widely between event loops.
		155
133	To disable the watcher you have to destroy it (e.g. by setting the	156	To disable the watcher you have to destroy it (e.g. by setting the
134	variable you store it in to C<undef> or otherwise deleting all references	157	variable you store it in to C<undef> or otherwise deleting all references
135	to it).	158	to it).
136		159
137	All watchers are created by calling a method on the C<AnyEvent> class.	160	All watchers are created by calling a method on the C<AnyEvent> class.
…		…
153	=head2 I/O WATCHERS	176	=head2 I/O WATCHERS
154		177
155	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
156	with the following mandatory key-value pairs as arguments:	179	with the following mandatory key-value pairs as arguments:
157		180
158	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events	181	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
159	(AnyEvent might or might not keep a reference to this file handle). C<poll>	182	for events (AnyEvent might or might not keep a reference to this file
		183	handle). Note that only file handles pointing to things for which
		184	non-blocking operation makes sense are allowed. This includes sockets,
		185	most character devices, pipes, fifos and so on, but not for example files
		186	or block devices.
		187
160	must be a string that is either C<r> or C<w>, which creates a watcher	188	C<poll> must be a string that is either C<r> or C<w>, which creates a
161	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the	189	watcher waiting for "r"eadable or "w"ritable events, respectively.
		190
162	callback to invoke each time the file handle becomes ready.	191	C<cb> is the callback to invoke each time the file handle becomes ready.
163		192
164	Although the callback might get passed parameters, their value and	193	Although the callback might get passed parameters, their value and
165	presence is undefined and you cannot rely on them. Portable AnyEvent	194	presence is undefined and you cannot rely on them. Portable AnyEvent
166	callbacks cannot use arguments passed to I/O watcher callbacks.	195	callbacks cannot use arguments passed to I/O watcher callbacks.
167		196
…		…
299	In either case, if you care (and in most cases, you don't), then you	328	In either case, if you care (and in most cases, you don't), then you
300	can get whatever behaviour you want with any event loop, by taking the	329	can get whatever behaviour you want with any event loop, by taking the
301	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	330	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
302	account.	331	account.
303		332
		333	=item AnyEvent->now_update
		334
		335	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		336	the current time for each loop iteration (see the discussion of L<<
		337	AnyEvent->now >>, above).
		338
		339	When a callback runs for a long time (or when the process sleeps), then
		340	this "current" time will differ substantially from the real time, which
		341	might affect timers and time-outs.
		342
		343	When this is the case, you can call this method, which will update the
		344	event loop's idea of "current time".
		345
		346	Note that updating the time I<might> cause some events to be handled.
		347
304	=back	348	=back
305		349
306	=head2 SIGNAL WATCHERS	350	=head2 SIGNAL WATCHERS
307		351
308	You can watch for signals using a signal watcher, C<signal> is the signal	352	You can watch for signals using a signal watcher, C<signal> is the signal
…		…
331	=head2 CHILD PROCESS WATCHERS	375	=head2 CHILD PROCESS WATCHERS
332		376
333	You can also watch on a child process exit and catch its exit status.	377	You can also watch on a child process exit and catch its exit status.
334		378
335	The child process is specified by the C<pid> argument (if set to C<0>, it	379	The child process is specified by the C<pid> argument (if set to C<0>, it
336	watches for any child process exit). The watcher will trigger as often	380	watches for any child process exit). The watcher will triggered only when
337	as status change for the child are received. This works by installing a	381	the child process has finished and an exit status is available, not on
338	signal handler for C<SIGCHLD>. The callback will be called with the pid	382	any trace events (stopped/continued).
339	and exit status (as returned by waitpid), so unlike other watcher types,	383
340	you I<can> rely on child watcher callback arguments.	384	The callback will be called with the pid and exit status (as returned by
		385	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		386	callback arguments.
		387
		388	This watcher type works by installing a signal handler for C<SIGCHLD>,
		389	and since it cannot be shared, nothing else should use SIGCHLD or reap
		390	random child processes (waiting for specific child processes, e.g. inside
		391	C<system>, is just fine).
341		392
342	There is a slight catch to child watchers, however: you usually start them	393	There is a slight catch to child watchers, however: you usually start them
343	I<after> the child process was created, and this means the process could	394	I<after> the child process was created, and this means the process could
344	have exited already (and no SIGCHLD will be sent anymore).	395	have exited already (and no SIGCHLD will be sent anymore).
345		396
346	Not all event models handle this correctly (POE doesn't), but even for	397	Not all event models handle this correctly (neither POE nor IO::Async do,
		398	see their AnyEvent::Impl manpages for details), but even for event models
347	event models that I<do> handle this correctly, they usually need to be	399	that I<do> handle this correctly, they usually need to be loaded before
348	loaded before the process exits (i.e. before you fork in the first place).	400	the process exits (i.e. before you fork in the first place). AnyEvent's
		401	pure perl event loop handles all cases correctly regardless of when you
		402	start the watcher.
349		403
350	This means you cannot create a child watcher as the very first thing in an	404	This means you cannot create a child watcher as the very first
351	AnyEvent program, you I<have> to create at least one watcher before you	405	thing in an AnyEvent program, you I<have> to create at least one
352	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	406	watcher before you C<fork> the child (alternatively, you can call
		407	C<AnyEvent::detect>).
353		408
354	Example: fork a process and wait for it	409	Example: fork a process and wait for it
355		410
356	my $done = AnyEvent->condvar;	411	my $done = AnyEvent->condvar;
357		412
…		…
367	);	422	);
368		423
369	# do something else, then wait for process exit	424	# do something else, then wait for process exit
370	$done->recv;	425	$done->recv;
371		426
		427	=head2 IDLE WATCHERS
		428
		429	Sometimes there is a need to do something, but it is not so important
		430	to do it instantly, but only when there is nothing better to do. This
		431	"nothing better to do" is usually defined to be "no other events need
		432	attention by the event loop".
		433
		434	Idle watchers ideally get invoked when the event loop has nothing
		435	better to do, just before it would block the process to wait for new
		436	events. Instead of blocking, the idle watcher is invoked.
		437
		438	Most event loops unfortunately do not really support idle watchers (only
		439	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		440	will simply call the callback "from time to time".
		441
		442	Example: read lines from STDIN, but only process them when the
		443	program is otherwise idle:
		444
		445	my @lines; # read data
		446	my $idle_w;
		447	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		448	push @lines, scalar <STDIN>;
		449
		450	# start an idle watcher, if not already done
		451	$idle_w \|\|= AnyEvent->idle (cb => sub {
		452	# handle only one line, when there are lines left
		453	if (my $line = shift @lines) {
		454	print "handled when idle: $line";
		455	} else {
		456	# otherwise disable the idle watcher again
		457	undef $idle_w;
		458	}
		459	});
		460	});
		461
372	=head2 CONDITION VARIABLES	462	=head2 CONDITION VARIABLES
373		463
374	If you are familiar with some event loops you will know that all of them	464	If you are familiar with some event loops you will know that all of them
375	require you to run some blocking "loop", "run" or similar function that	465	require you to run some blocking "loop", "run" or similar function that
376	will actively watch for new events and call your callbacks.	466	will actively watch for new events and call your callbacks.
…		…
381	The instrument to do that is called a "condition variable", so called	471	The instrument to do that is called a "condition variable", so called
382	because they represent a condition that must become true.	472	because they represent a condition that must become true.
383		473
384	Condition variables can be created by calling the C<< AnyEvent->condvar	474	Condition variables can be created by calling the C<< AnyEvent->condvar
385	>> method, usually without arguments. The only argument pair allowed is	475	>> method, usually without arguments. The only argument pair allowed is
		476
386	C<cb>, which specifies a callback to be called when the condition variable	477	C<cb>, which specifies a callback to be called when the condition variable
387	becomes true.	478	becomes true, with the condition variable as the first argument (but not
		479	the results).
388		480
389	After creation, the condition variable is "false" until it becomes "true"	481	After creation, the condition variable is "false" until it becomes "true"
390	by calling the C<send> method (or calling the condition variable as if it	482	by calling the C<send> method (or calling the condition variable as if it
391	were a callback, read about the caveats in the description for the C<<	483	were a callback, read about the caveats in the description for the C<<
392	->send >> method).	484	->send >> method).
…		…
448		540
449	my $done = AnyEvent->condvar;	541	my $done = AnyEvent->condvar;
450	my $delay = AnyEvent->timer (after => 5, cb => $done);	542	my $delay = AnyEvent->timer (after => 5, cb => $done);
451	$done->recv;	543	$done->recv;
452		544
		545	Example: Imagine an API that returns a condvar and doesn't support
		546	callbacks. This is how you make a synchronous call, for example from
		547	the main program:
		548
		549	use AnyEvent::CouchDB;
		550
		551	...
		552
		553	my @info = $couchdb->info->recv;
		554
		555	And this is how you would just ste a callback to be called whenever the
		556	results are available:
		557
		558	$couchdb->info->cb (sub {
		559	my @info = $_[0]->recv;
		560	});
		561
453	=head3 METHODS FOR PRODUCERS	562	=head3 METHODS FOR PRODUCERS
454		563
455	These methods should only be used by the producing side, i.e. the	564	These methods should only be used by the producing side, i.e. the
456	code/module that eventually sends the signal. Note that it is also	565	code/module that eventually sends the signal. Note that it is also
457	the producer side which creates the condvar in most cases, but it isn't	566	the producer side which creates the condvar in most cases, but it isn't
…		…
490		599
491	=item $cv->begin ([group callback])	600	=item $cv->begin ([group callback])
492		601
493	=item $cv->end	602	=item $cv->end
494		603
495	These two methods are EXPERIMENTAL and MIGHT CHANGE.
496
497	These two methods can be used to combine many transactions/events into	604	These two methods can be used to combine many transactions/events into
498	one. For example, a function that pings many hosts in parallel might want	605	one. For example, a function that pings many hosts in parallel might want
499	to use a condition variable for the whole process.	606	to use a condition variable for the whole process.
500		607
501	Every call to C<< ->begin >> will increment a counter, and every call to	608	Every call to C<< ->begin >> will increment a counter, and every call to
502	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	609	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
503	>>, the (last) callback passed to C<begin> will be executed. That callback	610	>>, the (last) callback passed to C<begin> will be executed. That callback
504	is I<supposed> to call C<< ->send >>, but that is not required. If no	611	is I<supposed> to call C<< ->send >>, but that is not required. If no
505	callback was set, C<send> will be called without any arguments.	612	callback was set, C<send> will be called without any arguments.
506		613
507	Let's clarify this with the ping example:	614	You can think of C<< $cv->send >> giving you an OR condition (one call
		615	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		616	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		617
		618	Let's start with a simple example: you have two I/O watchers (for example,
		619	STDOUT and STDERR for a program), and you want to wait for both streams to
		620	close before activating a condvar:
		621
		622	my $cv = AnyEvent->condvar;
		623
		624	$cv->begin; # first watcher
		625	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		626	defined sysread $fh1, my $buf, 4096
		627	or $cv->end;
		628	});
		629
		630	$cv->begin; # second watcher
		631	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		632	defined sysread $fh2, my $buf, 4096
		633	or $cv->end;
		634	});
		635
		636	$cv->recv;
		637
		638	This works because for every event source (EOF on file handle), there is
		639	one call to C<begin>, so the condvar waits for all calls to C<end> before
		640	sending.
		641
		642	The ping example mentioned above is slightly more complicated, as the
		643	there are results to be passwd back, and the number of tasks that are
		644	begung can potentially be zero:
508		645
509	my $cv = AnyEvent->condvar;	646	my $cv = AnyEvent->condvar;
510		647
511	my %result;	648	my %result;
512	$cv->begin (sub { $cv->send (\%result) });	649	$cv->begin (sub { $cv->send (\%result) });
…		…
532	loop, which serves two important purposes: first, it sets the callback	669	loop, which serves two important purposes: first, it sets the callback
533	to be called once the counter reaches C<0>, and second, it ensures that	670	to be called once the counter reaches C<0>, and second, it ensures that
534	C<send> is called even when C<no> hosts are being pinged (the loop	671	C<send> is called even when C<no> hosts are being pinged (the loop
535	doesn't execute once).	672	doesn't execute once).
536		673
537	This is the general pattern when you "fan out" into multiple subrequests:	674	This is the general pattern when you "fan out" into multiple (but
538	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	675	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
539	is called at least once, and then, for each subrequest you start, call	676	the callback and ensure C<end> is called at least once, and then, for each
540	C<begin> and for each subrequest you finish, call C<end>.	677	subrequest you start, call C<begin> and for each subrequest you finish,
		678	call C<end>.
541		679
542	=back	680	=back
543		681
544	=head3 METHODS FOR CONSUMERS	682	=head3 METHODS FOR CONSUMERS
545		683
…		…
590	=item $bool = $cv->ready	728	=item $bool = $cv->ready
591		729
592	Returns true when the condition is "true", i.e. whether C<send> or	730	Returns true when the condition is "true", i.e. whether C<send> or
593	C<croak> have been called.	731	C<croak> have been called.
594		732
595	=item $cb = $cv->cb ([new callback])	733	=item $cb = $cv->cb ($cb->($cv))
596		734
597	This is a mutator function that returns the callback set and optionally	735	This is a mutator function that returns the callback set and optionally
598	replaces it before doing so.	736	replaces it before doing so.
599		737
600	The callback will be called when the condition becomes "true", i.e. when	738	The callback will be called when the condition becomes "true", i.e. when
601	C<send> or C<croak> are called, with the only argument being the condition	739	C<send> or C<croak> are called, with the only argument being the condition
602	variable itself. Calling C<recv> inside the callback or at any later time	740	variable itself. Calling C<recv> inside the callback or at any later time
603	is guaranteed not to block.	741	is guaranteed not to block.
		742
		743	=back
		744
		745	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		746
		747	The available backend classes are (every class has its own manpage):
		748
		749	=over 4
		750
		751	=item Backends that are autoprobed when no other event loop can be found.
		752
		753	EV is the preferred backend when no other event loop seems to be in
		754	use. If EV is not installed, then AnyEvent will try Event, and, failing
		755	that, will fall back to its own pure-perl implementation, which is
		756	available everywhere as it comes with AnyEvent itself.
		757
		758	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		759	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		760	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		761
		762	=item Backends that are transparently being picked up when they are used.
		763
		764	These will be used when they are currently loaded when the first watcher
		765	is created, in which case it is assumed that the application is using
		766	them. This means that AnyEvent will automatically pick the right backend
		767	when the main program loads an event module before anything starts to
		768	create watchers. Nothing special needs to be done by the main program.
		769
		770	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		771	AnyEvent::Impl::Tk based on Tk, very broken.
		772	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		773	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		774
		775	=item Backends with special needs.
		776
		777	Qt requires the Qt::Application to be instantiated first, but will
		778	otherwise be picked up automatically. As long as the main program
		779	instantiates the application before any AnyEvent watchers are created,
		780	everything should just work.
		781
		782	AnyEvent::Impl::Qt based on Qt.
		783
		784	Support for IO::Async can only be partial, as it is too broken and
		785	architecturally limited to even support the AnyEvent API. It also
		786	is the only event loop that needs the loop to be set explicitly, so
		787	it can only be used by a main program knowing about AnyEvent. See
		788	L<AnyEvent::Impl::Async> for the gory details.
		789
		790	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		791
		792	=item Event loops that are indirectly supported via other backends.
		793
		794	Some event loops can be supported via other modules:
		795
		796	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		797
		798	B<WxWidgets> has no support for watching file handles. However, you can
		799	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		800	polls 20 times per second, which was considered to be too horrible to even
		801	consider for AnyEvent.
		802
		803	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		804	backend, so it can be supported through POE.
		805
		806	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		807	load L<POE> when detecting them, in the hope that POE will pick them up,
		808	in which case everything will be automatic.
604		809
605	=back	810	=back
606		811
607	=head1 GLOBAL VARIABLES AND FUNCTIONS	812	=head1 GLOBAL VARIABLES AND FUNCTIONS
608		813
…		…
613	Contains C<undef> until the first watcher is being created. Then it	818	Contains C<undef> until the first watcher is being created. Then it
614	contains the event model that is being used, which is the name of the	819	contains the event model that is being used, which is the name of the
615	Perl class implementing the model. This class is usually one of the	820	Perl class implementing the model. This class is usually one of the
616	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	821	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
617	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	822	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
618
619	The known classes so far are:
620
621	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
622	AnyEvent::Impl::Event based on Event, second best choice.
623	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
624	AnyEvent::Impl::Glib based on Glib, third-best choice.
625	AnyEvent::Impl::Tk based on Tk, very bad choice.
626	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
627	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
628	AnyEvent::Impl::POE based on POE, not generic enough for full support.
629
630	There is no support for WxWidgets, as WxWidgets has no support for
631	watching file handles. However, you can use WxWidgets through the
632	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
633	second, which was considered to be too horrible to even consider for
634	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
635	it's adaptor.
636
637	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
638	autodetecting them.
639		823
640	=item AnyEvent::detect	824	=item AnyEvent::detect
641		825
642	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	826	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
643	if necessary. You should only call this function right before you would	827	if necessary. You should only call this function right before you would
…		…
726		910
727		911
728	=head1 OTHER MODULES	912	=head1 OTHER MODULES
729		913
730	The following is a non-exhaustive list of additional modules that use	914	The following is a non-exhaustive list of additional modules that use
731	AnyEvent and can therefore be mixed easily with other AnyEvent modules	915	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
732	in the same program. Some of the modules come with AnyEvent, some are	916	modules and other event loops in the same program. Some of the modules
733	available via CPAN.	917	come with AnyEvent, most are available via CPAN.
734		918
735	=over 4	919	=over 4
736		920
737	=item L<AnyEvent::Util>	921	=item L<AnyEvent::Util>
738		922
…		…
747		931
748	=item L<AnyEvent::Handle>	932	=item L<AnyEvent::Handle>
749		933
750	Provide read and write buffers, manages watchers for reads and writes,	934	Provide read and write buffers, manages watchers for reads and writes,
751	supports raw and formatted I/O, I/O queued and fully transparent and	935	supports raw and formatted I/O, I/O queued and fully transparent and
752	non-blocking SSL/TLS.	936	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
753		937
754	=item L<AnyEvent::DNS>	938	=item L<AnyEvent::DNS>
755		939
756	Provides rich asynchronous DNS resolver capabilities.	940	Provides rich asynchronous DNS resolver capabilities.
757		941
…		…
785		969
786	=item L<AnyEvent::GPSD>	970	=item L<AnyEvent::GPSD>
787		971
788	A non-blocking interface to gpsd, a daemon delivering GPS information.	972	A non-blocking interface to gpsd, a daemon delivering GPS information.
789		973
		974	=item L<AnyEvent::IRC>
		975
		976	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		977
		978	=item L<AnyEvent::XMPP>
		979
		980	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		981	Net::XMPP2>.
		982
790	=item L<AnyEvent::IGS>	983	=item L<AnyEvent::IGS>
791		984
792	A non-blocking interface to the Internet Go Server protocol (used by	985	A non-blocking interface to the Internet Go Server protocol (used by
793	L<App::IGS>).	986	L<App::IGS>).
794		987
795	=item L<Net::IRC3>
796
797	AnyEvent based IRC client module family.
798
799	=item L<Net::XMPP2>
800
801	AnyEvent based XMPP (Jabber protocol) module family.
802
803	=item L<Net::FCP>	988	=item L<Net::FCP>
804		989
805	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	990	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
806	of AnyEvent.	991	of AnyEvent.
807		992
…		…
811		996
812	=item L<Coro>	997	=item L<Coro>
813		998
814	Has special support for AnyEvent via L<Coro::AnyEvent>.	999	Has special support for AnyEvent via L<Coro::AnyEvent>.
815		1000
816	=item L<IO::Lambda>
817
818	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
819
820	=back	1001	=back
821		1002
822	=cut	1003	=cut
823		1004
824	package AnyEvent;	1005	package AnyEvent;
825		1006
826	no warnings;	1007	no warnings;
827	use strict;	1008	use strict qw(vars subs);
828		1009
829	use Carp;	1010	use Carp;
830		1011
831	our $VERSION = 4.2;	1012	our $VERSION = 4.801;
832	our $MODEL;	1013	our $MODEL;
833		1014
834	our $AUTOLOAD;	1015	our $AUTOLOAD;
835	our @ISA;	1016	our @ISA;
836		1017
837	our @REGISTRY;	1018	our @REGISTRY;
838		1019
839	our $WIN32;	1020	our $WIN32;
840		1021
841	BEGIN {	1022	BEGIN {
842	my $win32 = ! ! ($^O =~ /mswin32/i);	1023	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
843	eval "sub WIN32(){ $win32 }";	1024	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
		1025
		1026	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1027	if ${^TAINT};
844	}	1028	}
845		1029
846	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1030	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
847		1031
848	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred	1032	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
…		…
859	[Event:: => AnyEvent::Impl::Event::],	1043	[Event:: => AnyEvent::Impl::Event::],
860	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1044	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
861	# everything below here will not be autoprobed	1045	# everything below here will not be autoprobed
862	# as the pureperl backend should work everywhere	1046	# as the pureperl backend should work everywhere
863	# and is usually faster	1047	# and is usually faster
864	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
865	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1048	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
866	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1049	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1050	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		1051	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
867	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1052	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
868	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
869	[Wx:: => AnyEvent::Impl::POE::],	1053	[Wx:: => AnyEvent::Impl::POE::],
870	[Prima:: => AnyEvent::Impl::POE::],	1054	[Prima:: => AnyEvent::Impl::POE::],
		1055	# IO::Async is just too broken - we would need workarounds for its
		1056	# byzantine signal and broken child handling, among others.
		1057	# IO::Async is rather hard to detect, as it doesn't have any
		1058	# obvious default class.
		1059	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1060	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1061	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
871	);	1062	);
872		1063
873	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1064	our %method = map +($_ => 1),
		1065	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
874		1066
875	our @post_detect;	1067	our @post_detect;
876		1068
877	sub post_detect(&) {	1069	sub post_detect(&) {
878	my ($cb) = @_;	1070	my ($cb) = @_;
…		…
883	1	1075	1
884	} else {	1076	} else {
885	push @post_detect, $cb;	1077	push @post_detect, $cb;
886		1078
887	defined wantarray	1079	defined wantarray
888	? bless \$cb, "AnyEvent::Util::PostDetect"	1080	? bless \$cb, "AnyEvent::Util::postdetect"
889	: ()	1081	: ()
890	}	1082	}
891	}	1083	}
892		1084
893	sub AnyEvent::Util::PostDetect::DESTROY {	1085	sub AnyEvent::Util::postdetect::DESTROY {
894	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1086	@post_detect = grep $_ != ${$_[0]}, @post_detect;
895	}	1087	}
896		1088
897	sub detect() {	1089	sub detect() {
898	unless ($MODEL) {	1090	unless ($MODEL) {
…		…
935	last;	1127	last;
936	}	1128	}
937	}	1129	}
938		1130
939	$MODEL	1131	$MODEL
940	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1132	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
941	}	1133	}
942	}	1134	}
943		1135
944	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1136	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
945		1137
…		…
966	}	1158	}
967		1159
968	# utility function to dup a filehandle. this is used by many backends	1160	# utility function to dup a filehandle. this is used by many backends
969	# to support binding more than one watcher per filehandle (they usually	1161	# to support binding more than one watcher per filehandle (they usually
970	# allow only one watcher per fd, so we dup it to get a different one).	1162	# allow only one watcher per fd, so we dup it to get a different one).
971	sub _dupfh($$$$) {	1163	sub _dupfh($$;$$) {
972	my ($poll, $fh, $r, $w) = @_;	1164	my ($poll, $fh, $r, $w) = @_;
973		1165
974	require Fcntl;
975
976	# cygwin requires the fh mode to be matching, unix doesn't	1166	# cygwin requires the fh mode to be matching, unix doesn't
977	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1167	my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">");
978	: $poll eq "w" ? ($w, ">")
979	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
980		1168
981	open my $fh2, "$mode&" . fileno $fh	1169	open my $fh2, "$mode&", $fh
982	or die "cannot dup() filehandle: $!";	1170	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
983		1171
984	# we assume CLOEXEC is already set by perl in all important cases	1172	# we assume CLOEXEC is already set by perl in all important cases
985		1173
986	($fh2, $rw)	1174	($fh2, $rw)
987	}	1175	}
988		1176
989	package AnyEvent::Base;	1177	package AnyEvent::Base;
990		1178
991	# default implementation for now and time	1179	# default implementations for many methods
992		1180
993	use Time::HiRes ();	1181	BEGIN {
		1182	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1183	*_time = \&Time::HiRes::time;
		1184	# if (eval "use POSIX (); (POSIX::times())...
		1185	} else {
		1186	*_time = sub { time }; # epic fail
		1187	}
		1188	}
994		1189
995	sub time { Time::HiRes::time }	1190	sub time { _time }
996	sub now { Time::HiRes::time }	1191	sub now { _time }
		1192	sub now_update { }
997		1193
998	# default implementation for ->condvar	1194	# default implementation for ->condvar
999		1195
1000	sub condvar {	1196	sub condvar {
1001	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1197	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1002	}	1198	}
1003		1199
1004	# default implementation for ->signal	1200	# default implementation for ->signal
1005		1201
1006	our %SIG_CB;	1202	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1203
		1204	sub _signal_exec {
		1205	sysread $SIGPIPE_R, my $dummy, 4;
		1206
		1207	while (%SIG_EV) {
		1208	for (keys %SIG_EV) {
		1209	delete $SIG_EV{$_};
		1210	$_->() for values %{ $SIG_CB{$_} \|\| {} };
		1211	}
		1212	}
		1213	}
1007		1214
1008	sub signal {	1215	sub signal {
1009	my (undef, %arg) = @_;	1216	my (undef, %arg) = @_;
1010		1217
		1218	unless ($SIGPIPE_R) {
		1219	require Fcntl;
		1220
		1221	if (AnyEvent::WIN32) {
		1222	require AnyEvent::Util;
		1223
		1224	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1225	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1226	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1227	} else {
		1228	pipe $SIGPIPE_R, $SIGPIPE_W;
		1229	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1230	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1231
		1232	# not strictly required, as $^F is normally 2, but let's make sure...
		1233	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1234	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1235	}
		1236
		1237	$SIGPIPE_R
		1238	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1239
		1240	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1241	}
		1242
1011	my $signal = uc $arg{signal}	1243	my $signal = uc $arg{signal}
1012	or Carp::croak "required option 'signal' is missing";	1244	or Carp::croak "required option 'signal' is missing";
1013		1245
1014	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1246	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1015	$SIG{$signal} \|\|= sub {	1247	$SIG{$signal} \|\|= sub {
1016	$_->() for values %{ $SIG_CB{$signal} \|\| {} };	1248	local $!;
		1249	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1250	undef $SIG_EV{$signal};
1017	};	1251	};
1018		1252
1019	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1253	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1020	}	1254	}
1021		1255
1022	sub AnyEvent::Base::Signal::DESTROY {	1256	sub AnyEvent::Base::signal::DESTROY {
1023	my ($signal, $cb) = @{$_[0]};	1257	my ($signal, $cb) = @{$_[0]};
1024		1258
1025	delete $SIG_CB{$signal}{$cb};	1259	delete $SIG_CB{$signal}{$cb};
1026		1260
		1261	# delete doesn't work with older perls - they then
		1262	# print weird messages, or just unconditionally exit
		1263	# instead of getting the default action.
1027	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };	1264	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1028	}	1265	}
1029		1266
1030	# default implementation for ->child	1267	# default implementation for ->child
1031		1268
1032	our %PID_CB;	1269	our %PID_CB;
1033	our $CHLD_W;	1270	our $CHLD_W;
1034	our $CHLD_DELAY_W;	1271	our $CHLD_DELAY_W;
1035	our $PID_IDLE;
1036	our $WNOHANG;	1272	our $WNOHANG;
1037		1273
1038	sub _child_wait {	1274	sub _sigchld {
1039	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1275	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1040	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),	1276	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),
1041	(values %{ $PID_CB{0} \|\| {} });	1277	(values %{ $PID_CB{0} \|\| {} });
1042	}	1278	}
1043
1044	undef $PID_IDLE;
1045	}
1046
1047	sub _sigchld {
1048	# make sure we deliver these changes "synchronous" with the event loop.
1049	$CHLD_DELAY_W \|\|= AnyEvent->timer (after => 0, cb => sub {
1050	undef $CHLD_DELAY_W;
1051	&_child_wait;
1052	});
1053	}	1279	}
1054		1280
1055	sub child {	1281	sub child {
1056	my (undef, %arg) = @_;	1282	my (undef, %arg) = @_;
1057		1283
1058	defined (my $pid = $arg{pid} + 0)	1284	defined (my $pid = $arg{pid} + 0)
1059	or Carp::croak "required option 'pid' is missing";	1285	or Carp::croak "required option 'pid' is missing";
1060		1286
1061	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1287	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1062		1288
1063	unless ($WNOHANG) {
1064	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;	1289	$WNOHANG \|\|= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
1065	}
1066		1290
1067	unless ($CHLD_W) {	1291	unless ($CHLD_W) {
1068	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1292	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1069	# child could be a zombie already, so make at least one round	1293	# child could be a zombie already, so make at least one round
1070	&_sigchld;	1294	&_sigchld;
1071	}	1295	}
1072		1296
1073	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1297	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1074	}	1298	}
1075		1299
1076	sub AnyEvent::Base::Child::DESTROY {	1300	sub AnyEvent::Base::child::DESTROY {
1077	my ($pid, $cb) = @{$_[0]};	1301	my ($pid, $cb) = @{$_[0]};
1078		1302
1079	delete $PID_CB{$pid}{$cb};	1303	delete $PID_CB{$pid}{$cb};
1080	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1304	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1081		1305
1082	undef $CHLD_W unless keys %PID_CB;	1306	undef $CHLD_W unless keys %PID_CB;
		1307	}
		1308
		1309	# idle emulation is done by simply using a timer, regardless
		1310	# of whether the process is idle or not, and not letting
		1311	# the callback use more than 50% of the time.
		1312	sub idle {
		1313	my (undef, %arg) = @_;
		1314
		1315	my ($cb, $w, $rcb) = $arg{cb};
		1316
		1317	$rcb = sub {
		1318	if ($cb) {
		1319	$w = _time;
		1320	&$cb;
		1321	$w = _time - $w;
		1322
		1323	# never use more then 50% of the time for the idle watcher,
		1324	# within some limits
		1325	$w = 0.0001 if $w < 0.0001;
		1326	$w = 5 if $w > 5;
		1327
		1328	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1329	} else {
		1330	# clean up...
		1331	undef $w;
		1332	undef $rcb;
		1333	}
		1334	};
		1335
		1336	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1337
		1338	bless \\$cb, "AnyEvent::Base::idle"
		1339	}
		1340
		1341	sub AnyEvent::Base::idle::DESTROY {
		1342	undef $${$_[0]};
1083	}	1343	}
1084		1344
1085	package AnyEvent::CondVar;	1345	package AnyEvent::CondVar;
1086		1346
1087	our @ISA = AnyEvent::CondVar::Base::;	1347	our @ISA = AnyEvent::CondVar::Base::;
…		…
1139	}	1399	}
1140		1400
1141	# undocumented/compatibility with pre-3.4	1401	# undocumented/compatibility with pre-3.4
1142	*broadcast = \&send;	1402	*broadcast = \&send;
1143	*wait = \&_wait;	1403	*wait = \&_wait;
		1404
		1405	=head1 ERROR AND EXCEPTION HANDLING
		1406
		1407	In general, AnyEvent does not do any error handling - it relies on the
		1408	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1409	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1410	checking of all AnyEvent methods, however, which is highly useful during
		1411	development.
		1412
		1413	As for exception handling (i.e. runtime errors and exceptions thrown while
		1414	executing a callback), this is not only highly event-loop specific, but
		1415	also not in any way wrapped by this module, as this is the job of the main
		1416	program.
		1417
		1418	The pure perl event loop simply re-throws the exception (usually
		1419	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1420	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1421	so on.
		1422
		1423	=head1 ENVIRONMENT VARIABLES
		1424
		1425	The following environment variables are used by this module or its
		1426	submodules.
		1427
		1428	Note that AnyEvent will remove I<all> environment variables starting with
		1429	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1430	enabled.
		1431
		1432	=over 4
		1433
		1434	=item C<PERL_ANYEVENT_VERBOSE>
		1435
		1436	By default, AnyEvent will be completely silent except in fatal
		1437	conditions. You can set this environment variable to make AnyEvent more
		1438	talkative.
		1439
		1440	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1441	conditions, such as not being able to load the event model specified by
		1442	C<PERL_ANYEVENT_MODEL>.
		1443
		1444	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1445	model it chooses.
		1446
		1447	=item C<PERL_ANYEVENT_STRICT>
		1448
		1449	AnyEvent does not do much argument checking by default, as thorough
		1450	argument checking is very costly. Setting this variable to a true value
		1451	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1452	check the arguments passed to most method calls. If it finds any problems,
		1453	it will croak.
		1454
		1455	In other words, enables "strict" mode.
		1456
		1457	Unlike C<use strict>, it is definitely recommended to keep it off in
		1458	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1459	developing programs can be very useful, however.
		1460
		1461	=item C<PERL_ANYEVENT_MODEL>
		1462
		1463	This can be used to specify the event model to be used by AnyEvent, before
		1464	auto detection and -probing kicks in. It must be a string consisting
		1465	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1466	and the resulting module name is loaded and if the load was successful,
		1467	used as event model. If it fails to load AnyEvent will proceed with
		1468	auto detection and -probing.
		1469
		1470	This functionality might change in future versions.
		1471
		1472	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1473	could start your program like this:
		1474
		1475	PERL_ANYEVENT_MODEL=Perl perl ...
		1476
		1477	=item C<PERL_ANYEVENT_PROTOCOLS>
		1478
		1479	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1480	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1481	of auto probing).
		1482
		1483	Must be set to a comma-separated list of protocols or address families,
		1484	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1485	used, and preference will be given to protocols mentioned earlier in the
		1486	list.
		1487
		1488	This variable can effectively be used for denial-of-service attacks
		1489	against local programs (e.g. when setuid), although the impact is likely
		1490	small, as the program has to handle conenction and other failures anyways.
		1491
		1492	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1493	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1494	- only support IPv4, never try to resolve or contact IPv6
		1495	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1496	IPv6, but prefer IPv6 over IPv4.
		1497
		1498	=item C<PERL_ANYEVENT_EDNS0>
		1499
		1500	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1501	for DNS. This extension is generally useful to reduce DNS traffic, but
		1502	some (broken) firewalls drop such DNS packets, which is why it is off by
		1503	default.
		1504
		1505	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1506	EDNS0 in its DNS requests.
		1507
		1508	=item C<PERL_ANYEVENT_MAX_FORKS>
		1509
		1510	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1511	will create in parallel.
		1512
		1513	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1514
		1515	The default value for the C<max_outstanding> parameter for the default DNS
		1516	resolver - this is the maximum number of parallel DNS requests that are
		1517	sent to the DNS server.
		1518
		1519	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1520
		1521	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1522	configuration) in the default resolver. When set to the empty string, no
		1523	default config will be used.
		1524
		1525	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1526
		1527	When neither C<ca_file> nor C<ca_path> was specified during
		1528	L<AnyEvent::TLS> context creation, and either of these environment
		1529	variables exist, they will be used to specify CA certificate locations
		1530	instead of a system-dependent default.
		1531
		1532	=back
1144		1533
1145	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1534	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1146		1535
1147	This is an advanced topic that you do not normally need to use AnyEvent in	1536	This is an advanced topic that you do not normally need to use AnyEvent in
1148	a module. This section is only of use to event loop authors who want to	1537	a module. This section is only of use to event loop authors who want to
…		…
1182		1571
1183	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1572	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1184	condition variables: code blocking while waiting for a condition will	1573	condition variables: code blocking while waiting for a condition will
1185	C<die>. This still works with most modules/usages, and blocking calls must	1574	C<die>. This still works with most modules/usages, and blocking calls must
1186	not be done in an interactive application, so it makes sense.	1575	not be done in an interactive application, so it makes sense.
1187
1188	=head1 ENVIRONMENT VARIABLES
1189
1190	The following environment variables are used by this module:
1191
1192	=over 4
1193
1194	=item C<PERL_ANYEVENT_VERBOSE>
1195
1196	By default, AnyEvent will be completely silent except in fatal
1197	conditions. You can set this environment variable to make AnyEvent more
1198	talkative.
1199
1200	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1201	conditions, such as not being able to load the event model specified by
1202	C<PERL_ANYEVENT_MODEL>.
1203
1204	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1205	model it chooses.
1206
1207	=item C<PERL_ANYEVENT_STRICT>
1208
1209	AnyEvent does not do much argument checking by default, as thorough
1210	argument checking is very costly. Setting this variable to a true value
1211	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1212	check the arguments passed to most method calls. If it finds any problems
1213	it will croak.
1214
1215	In other words, enables "strict" mode.
1216
1217	Unlike C<use strict> it is definitely recommended ot keep it off in
1218	production.
1219
1220	=item C<PERL_ANYEVENT_MODEL>
1221
1222	This can be used to specify the event model to be used by AnyEvent, before
1223	auto detection and -probing kicks in. It must be a string consisting
1224	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1225	and the resulting module name is loaded and if the load was successful,
1226	used as event model. If it fails to load AnyEvent will proceed with
1227	auto detection and -probing.
1228
1229	This functionality might change in future versions.
1230
1231	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1232	could start your program like this:
1233
1234	PERL_ANYEVENT_MODEL=Perl perl ...
1235
1236	=item C<PERL_ANYEVENT_PROTOCOLS>
1237
1238	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1239	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1240	of auto probing).
1241
1242	Must be set to a comma-separated list of protocols or address families,
1243	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1244	used, and preference will be given to protocols mentioned earlier in the
1245	list.
1246
1247	This variable can effectively be used for denial-of-service attacks
1248	against local programs (e.g. when setuid), although the impact is likely
1249	small, as the program has to handle connection errors already-
1250
1251	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1252	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1253	- only support IPv4, never try to resolve or contact IPv6
1254	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1255	IPv6, but prefer IPv6 over IPv4.
1256
1257	=item C<PERL_ANYEVENT_EDNS0>
1258
1259	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1260	for DNS. This extension is generally useful to reduce DNS traffic, but
1261	some (broken) firewalls drop such DNS packets, which is why it is off by
1262	default.
1263
1264	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1265	EDNS0 in its DNS requests.
1266
1267	=item C<PERL_ANYEVENT_MAX_FORKS>
1268
1269	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1270	will create in parallel.
1271
1272	=back
1273		1576
1274	=head1 EXAMPLE PROGRAM	1577	=head1 EXAMPLE PROGRAM
1275		1578
1276	The following program uses an I/O watcher to read data from STDIN, a timer	1579	The following program uses an I/O watcher to read data from STDIN, a timer
1277	to display a message once per second, and a condition variable to quit the	1580	to display a message once per second, and a condition variable to quit the
…		…
1471	watcher.	1774	watcher.
1472		1775
1473	=head3 Results	1776	=head3 Results
1474		1777
1475	name watchers bytes create invoke destroy comment	1778	name watchers bytes create invoke destroy comment
1476	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1779	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1477	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1780	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1478	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1781	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1479	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1782	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1480	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1783	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1481	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	1784	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		1785	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		1786	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1482	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1787	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1483	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1788	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1484	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1789	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1485	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1790	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1486		1791
1487	=head3 Discussion	1792	=head3 Discussion
1488		1793
1489	The benchmark does I<not> measure scalability of the event loop very	1794	The benchmark does I<not> measure scalability of the event loop very
1490	well. For example, a select-based event loop (such as the pure perl one)	1795	well. For example, a select-based event loop (such as the pure perl one)
…		…
1515	performance becomes really bad with lots of file descriptors (and few of	1820	performance becomes really bad with lots of file descriptors (and few of
1516	them active), of course, but this was not subject of this benchmark.	1821	them active), of course, but this was not subject of this benchmark.
1517		1822
1518	The C<Event> module has a relatively high setup and callback invocation	1823	The C<Event> module has a relatively high setup and callback invocation
1519	cost, but overall scores in on the third place.	1824	cost, but overall scores in on the third place.
		1825
		1826	C<IO::Async> performs admirably well, about on par with C<Event>, even
		1827	when using its pure perl backend.
1520		1828
1521	C<Glib>'s memory usage is quite a bit higher, but it features a	1829	C<Glib>'s memory usage is quite a bit higher, but it features a
1522	faster callback invocation and overall ends up in the same class as	1830	faster callback invocation and overall ends up in the same class as
1523	C<Event>. However, Glib scales extremely badly, doubling the number of	1831	C<Event>. However, Glib scales extremely badly, doubling the number of
1524	watchers increases the processing time by more than a factor of four,	1832	watchers increases the processing time by more than a factor of four,
…		…
1602	it to another server. This includes deleting the old timeout and creating	1910	it to another server. This includes deleting the old timeout and creating
1603	a new one that moves the timeout into the future.	1911	a new one that moves the timeout into the future.
1604		1912
1605	=head3 Results	1913	=head3 Results
1606		1914
1607	name sockets create request	1915	name sockets create request
1608	EV 20000 69.01 11.16	1916	EV 20000 69.01 11.16
1609	Perl 20000 73.32 35.87	1917	Perl 20000 73.32 35.87
		1918	IOAsync 20000 157.00 98.14 epoll
		1919	IOAsync 20000 159.31 616.06 poll
1610	Event 20000 212.62 257.32	1920	Event 20000 212.62 257.32
1611	Glib 20000 651.16 1896.30	1921	Glib 20000 651.16 1896.30
1612	POE 20000 349.67 12317.24 uses POE::Loop::Event	1922	POE 20000 349.67 12317.24 uses POE::Loop::Event
1613		1923
1614	=head3 Discussion	1924	=head3 Discussion
1615		1925
1616	This benchmark I<does> measure scalability and overall performance of the	1926	This benchmark I<does> measure scalability and overall performance of the
1617	particular event loop.	1927	particular event loop.
…		…
1619	EV is again fastest. Since it is using epoll on my system, the setup time	1929	EV is again fastest. Since it is using epoll on my system, the setup time
1620	is relatively high, though.	1930	is relatively high, though.
1621		1931
1622	Perl surprisingly comes second. It is much faster than the C-based event	1932	Perl surprisingly comes second. It is much faster than the C-based event
1623	loops Event and Glib.	1933	loops Event and Glib.
		1934
		1935	IO::Async performs very well when using its epoll backend, and still quite
		1936	good compared to Glib when using its pure perl backend.
1624		1937
1625	Event suffers from high setup time as well (look at its code and you will	1938	Event suffers from high setup time as well (look at its code and you will
1626	understand why). Callback invocation also has a high overhead compared to	1939	understand why). Callback invocation also has a high overhead compared to
1627	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	1940	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1628	uses select or poll in basically all documented configurations.	1941	uses select or poll in basically all documented configurations.
…		…
1691	=item * C-based event loops perform very well with small number of	2004	=item * C-based event loops perform very well with small number of
1692	watchers, as the management overhead dominates.	2005	watchers, as the management overhead dominates.
1693		2006
1694	=back	2007	=back
1695		2008
		2009	=head2 THE IO::Lambda BENCHMARK
		2010
		2011	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2012	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2013	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2014	shouldn't come as a surprise to anybody). As such, the benchmark is
		2015	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2016	very optimal. But how would AnyEvent compare when used without the extra
		2017	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2018
		2019	The benchmark itself creates an echo-server, and then, for 500 times,
		2020	connects to the echo server, sends a line, waits for the reply, and then
		2021	creates the next connection. This is a rather bad benchmark, as it doesn't
		2022	test the efficiency of the framework or much non-blocking I/O, but it is a
		2023	benchmark nevertheless.
		2024
		2025	name runtime
		2026	Lambda/select 0.330 sec
		2027	+ optimized 0.122 sec
		2028	Lambda/AnyEvent 0.327 sec
		2029	+ optimized 0.138 sec
		2030	Raw sockets/select 0.077 sec
		2031	POE/select, components 0.662 sec
		2032	POE/select, raw sockets 0.226 sec
		2033	POE/select, optimized 0.404 sec
		2034
		2035	AnyEvent/select/nb 0.085 sec
		2036	AnyEvent/EV/nb 0.068 sec
		2037	+state machine 0.134 sec
		2038
		2039	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2040	benchmarks actually make blocking connects and use 100% blocking I/O,
		2041	defeating the purpose of an event-based solution. All of the newly
		2042	written AnyEvent benchmarks use 100% non-blocking connects (using
		2043	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2044	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2045	generally require a lot more bookkeeping and event handling than blocking
		2046	connects (which involve a single syscall only).
		2047
		2048	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2049	offers similar expressive power as POE and IO::Lambda, using conventional
		2050	Perl syntax. This means that both the echo server and the client are 100%
		2051	non-blocking, further placing it at a disadvantage.
		2052
		2053	As you can see, the AnyEvent + EV combination even beats the
		2054	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2055	backend easily beats IO::Lambda and POE.
		2056
		2057	And even the 100% non-blocking version written using the high-level (and
		2058	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2059	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2060	in a non-blocking way.
		2061
		2062	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2063	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2064	part of the IO::lambda distribution and were used without any changes.
		2065
		2066
		2067	=head1 SIGNALS
		2068
		2069	AnyEvent currently installs handlers for these signals:
		2070
		2071	=over 4
		2072
		2073	=item SIGCHLD
		2074
		2075	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		2076	emulation for event loops that do not support them natively. Also, some
		2077	event loops install a similar handler.
		2078
		2079	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will
		2080	reset it to default, to avoid losing child exit statuses.
		2081
		2082	=item SIGPIPE
		2083
		2084	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		2085	when AnyEvent gets loaded.
		2086
		2087	The rationale for this is that AnyEvent users usually do not really depend
		2088	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		2089	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		2090	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		2091	some random socket.
		2092
		2093	The rationale for installing a no-op handler as opposed to ignoring it is
		2094	that this way, the handler will be restored to defaults on exec.
		2095
		2096	Feel free to install your own handler, or reset it to defaults.
		2097
		2098	=back
		2099
		2100	=cut
		2101
		2102	undef $SIG{CHLD}
		2103	if $SIG{CHLD} eq 'IGNORE';
		2104
		2105	$SIG{PIPE} = sub { }
		2106	unless defined $SIG{PIPE};
1696		2107
1697	=head1 FORK	2108	=head1 FORK
1698		2109
1699	Most event libraries are not fork-safe. The ones who are usually are	2110	Most event libraries are not fork-safe. The ones who are usually are
1700	because they rely on inefficient but fork-safe C<select> or C<poll>	2111	because they rely on inefficient but fork-safe C<select> or C<poll>
…		…
1721	use AnyEvent;	2132	use AnyEvent;
1722		2133
1723	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2134	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1724	be used to probe what backend is used and gain other information (which is	2135	be used to probe what backend is used and gain other information (which is
1725	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2136	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1726	$ENV{PERL_ANYEGENT_STRICT}.	2137	$ENV{PERL_ANYEVENT_STRICT}.
		2138
		2139	Note that AnyEvent will remove I<all> environment variables starting with
		2140	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2141	enabled.
1727		2142
1728		2143
1729	=head1 BUGS	2144	=head1 BUGS
1730		2145
1731	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2146	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1732	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2147	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1733	and check wether the leaks still show up. (Perl 5.10.0 has other annoying	2148	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1734	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as	2149	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1735	pronounced).	2150	pronounced).
1736		2151
1737		2152
1738	=head1 SEE ALSO	2153	=head1 SEE ALSO
1739		2154
…		…
1743	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2158	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1744		2159
1745	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2160	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1746	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2161	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1747	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2162	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1748	L<AnyEvent::Impl::POE>.	2163	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.
1749		2164
1750	Non-blocking file handles, sockets, TCP clients and	2165	Non-blocking file handles, sockets, TCP clients and
1751	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2166	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1752		2167
1753	Asynchronous DNS: L<AnyEvent::DNS>.	2168	Asynchronous DNS: L<AnyEvent::DNS>.
1754		2169
1755	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2170	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2171	L<Coro::Event>,
1756		2172
1757	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2173	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2174	L<AnyEvent::HTTP>.
1758		2175
1759		2176
1760	=head1 AUTHOR	2177	=head1 AUTHOR
1761		2178
1762	Marc Lehmann <schmorp@schmorp.de>	2179	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.170 by root, Wed Jul 9 11:53:40 2008 UTC vs. Revision 1.232 by root, Thu Jul 9 01:08:22 2009 UTC

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Revision 1.170 by root, Wed Jul 9 11:53:40 2008 UTC vs.
Revision 1.232 by root, Thu Jul 9 01:08:22 2009 UTC