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Revision 1.228 by root, Wed Jul 8 01:11:12 2009 UTC vs.
Revision 1.310 by root, Tue Jan 5 10:45:25 2010 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
6	event loops.	6	and POE are various supported event loops/environments.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
…		…
40	=head1 INTRODUCTION/TUTORIAL	40	=head1 INTRODUCTION/TUTORIAL
41		41
42	This manpage is mainly a reference manual. If you are interested	42	This manpage is mainly a reference manual. If you are interested
43	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
44	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.
45		53
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	54	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		55
48	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
49	nowadays. So what is different about AnyEvent?	57	nowadays. So what is different about AnyEvent?
…		…
173	my variables are only visible after the statement in which they are	181	my variables are only visible after the statement in which they are
174	declared.	182	declared.
175		183
176	=head2 I/O WATCHERS	184	=head2 I/O WATCHERS
177		185
		186	$w = AnyEvent->io (
		187	fh => <filehandle_or_fileno>,
		188	poll => <"r" or "w">,
		189	cb => <callback>,
		190	);
		191
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	192	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	193	with the following mandatory key-value pairs as arguments:
180		194
181	C<fh> is the Perl I<file handle> (I<not> file descriptor, see below) to	195	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
182	watch for events (AnyEvent might or might not keep a reference to this	196	for events (AnyEvent might or might not keep a reference to this file
183	file handle). Note that only file handles pointing to things for which	197	handle). Note that only file handles pointing to things for which
184	non-blocking operation makes sense are allowed. This includes sockets,	198	non-blocking operation makes sense are allowed. This includes sockets,
185	most character devices, pipes, fifos and so on, but not for example files	199	most character devices, pipes, fifos and so on, but not for example files
186	or block devices.	200	or block devices.
187		201
188	C<poll> must be a string that is either C<r> or C<w>, which creates a	202	C<poll> must be a string that is either C<r> or C<w>, which creates a
…		…
209	chomp (my $input = <STDIN>);	223	chomp (my $input = <STDIN>);
210	warn "read: $input\n";	224	warn "read: $input\n";
211	undef $w;	225	undef $w;
212	});	226	});
213		227
214	=head3 GETTING A FILE HANDLE FROM A FILE DESCRIPTOR
215
216	It is not uncommon to only have a file descriptor, while AnyEvent requires
217	a Perl file handle.
218
219	There are basically two methods to convert a file descriptor into a file handle. If you own
220	the file descriptor, you can open it with C<&=>, as in:
221
222	open my $fh, "<&=$fileno" or die "xxx: §!";
223
224	This will "own" the file descriptor, meaning that when C<$fh> is
225	destroyed, it will automatically close the C<$fileno>. Also, note that
226	the open mode (read, write, read/write) must correspond with how the
227	underlying file descriptor was opened.
228
229	In many cases, taking over the file descriptor is now what you want, in
230	which case the only alternative is to dup the file descriptor:
231
232	open my $fh, "<&$fileno" or die "xxx: $!";
233
234	This has the advantage of not closing the file descriptor and the
235	disadvantage of making a slow copy.
236
237	=head2 TIME WATCHERS	228	=head2 TIME WATCHERS
		229
		230	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		231
		232	$w = AnyEvent->timer (
		233	after => <fractional_seconds>,
		234	interval => <fractional_seconds>,
		235	cb => <callback>,
		236	);
238		237
239	You can create a time watcher by calling the C<< AnyEvent->timer >>	238	You can create a time watcher by calling the C<< AnyEvent->timer >>
240	method with the following mandatory arguments:	239	method with the following mandatory arguments:
241		240
242	C<after> specifies after how many seconds (fractional values are	241	C<after> specifies after how many seconds (fractional values are
…		…
364	might affect timers and time-outs.	363	might affect timers and time-outs.
365		364
366	When this is the case, you can call this method, which will update the	365	When this is the case, you can call this method, which will update the
367	event loop's idea of "current time".	366	event loop's idea of "current time".
368		367
		368	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		369	when mod_perl executes the script, then the event loop will have the wrong
		370	idea about the "current time" (being potentially far in the past, when the
		371	script ran the last time). In that case you should arrange a call to C<<
		372	AnyEvent->now_update >> each time the web server process wakes up again
		373	(e.g. at the start of your script, or in a handler).
		374
369	Note that updating the time I<might> cause some events to be handled.	375	Note that updating the time I<might> cause some events to be handled.
370		376
371	=back	377	=back
372		378
373	=head2 SIGNAL WATCHERS	379	=head2 SIGNAL WATCHERS
		380
		381	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
374		382
375	You can watch for signals using a signal watcher, C<signal> is the signal	383	You can watch for signals using a signal watcher, C<signal> is the signal
376	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	384	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
377	callback to be invoked whenever a signal occurs.	385	callback to be invoked whenever a signal occurs.
378		386
…		…
384	invocation, and callback invocation will be synchronous. Synchronous means	392	invocation, and callback invocation will be synchronous. Synchronous means
385	that it might take a while until the signal gets handled by the process,	393	that it might take a while until the signal gets handled by the process,
386	but it is guaranteed not to interrupt any other callbacks.	394	but it is guaranteed not to interrupt any other callbacks.
387		395
388	The main advantage of using these watchers is that you can share a signal	396	The main advantage of using these watchers is that you can share a signal
389	between multiple watchers.	397	between multiple watchers, and AnyEvent will ensure that signals will not
		398	interrupt your program at bad times.
390		399
391	This watcher might use C<%SIG>, so programs overwriting those signals	400	This watcher might use C<%SIG> (depending on the event loop used),
392	directly will likely not work correctly.	401	so programs overwriting those signals directly will likely not work
		402	correctly.
393		403
394	Example: exit on SIGINT	404	Example: exit on SIGINT
395		405
396	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	406	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
397		407
		408	=head3 Restart Behaviour
		409
		410	While restart behaviour is up to the event loop implementation, most will
		411	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		412	pure perl implementation).
		413
		414	=head3 Safe/Unsafe Signals
		415
		416	Perl signals can be either "safe" (synchronous to opcode handling) or
		417	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		418	latter might corrupt your memory.
		419
		420	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		421	i.e. they will not interrupt your running perl program but will only be
		422	called as part of the normal event handling (just like timer, I/O etc.
		423	callbacks, too).
		424
		425	=head3 Signal Races, Delays and Workarounds
		426
		427	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		428	callbacks to signals in a generic way, which is a pity, as you cannot
		429	do race-free signal handling in perl, requiring C libraries for
		430	this. AnyEvent will try to do it's best, which means in some cases,
		431	signals will be delayed. The maximum time a signal might be delayed is
		432	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		433	variable can be changed only before the first signal watcher is created,
		434	and should be left alone otherwise. This variable determines how often
		435	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		436	will cause fewer spurious wake-ups, which is better for power and CPU
		437	saving.
		438
		439	All these problems can be avoided by installing the optional
		440	L<Async::Interrupt> module, which works with most event loops. It will not
		441	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		442	(and not with L<POE> currently, as POE does it's own workaround with
		443	one-second latency). For those, you just have to suffer the delays.
		444
398	=head2 CHILD PROCESS WATCHERS	445	=head2 CHILD PROCESS WATCHERS
399		446
		447	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		448
400	You can also watch on a child process exit and catch its exit status.	449	You can also watch on a child process exit and catch its exit status.
401		450
402	The child process is specified by the C<pid> argument (if set to C<0>, it	451	The child process is specified by the C<pid> argument (one some backends,
403	watches for any child process exit). The watcher will triggered only when	452	using C<0> watches for any child process exit, on others this will
404	the child process has finished and an exit status is available, not on	453	croak). The watcher will be triggered only when the child process has
405	any trace events (stopped/continued).	454	finished and an exit status is available, not on any trace events
		455	(stopped/continued).
406		456
407	The callback will be called with the pid and exit status (as returned by	457	The callback will be called with the pid and exit status (as returned by
408	waitpid), so unlike other watcher types, you I<can> rely on child watcher	458	waitpid), so unlike other watcher types, you I<can> rely on child watcher
409	callback arguments.	459	callback arguments.
410		460
…		…
426		476
427	This means you cannot create a child watcher as the very first	477	This means you cannot create a child watcher as the very first
428	thing in an AnyEvent program, you I<have> to create at least one	478	thing in an AnyEvent program, you I<have> to create at least one
429	watcher before you C<fork> the child (alternatively, you can call	479	watcher before you C<fork> the child (alternatively, you can call
430	C<AnyEvent::detect>).	480	C<AnyEvent::detect>).
		481
		482	As most event loops do not support waiting for child events, they will be
		483	emulated by AnyEvent in most cases, in which the latency and race problems
		484	mentioned in the description of signal watchers apply.
431		485
432	Example: fork a process and wait for it	486	Example: fork a process and wait for it
433		487
434	my $done = AnyEvent->condvar;	488	my $done = AnyEvent->condvar;
435		489
…		…
447	# do something else, then wait for process exit	501	# do something else, then wait for process exit
448	$done->recv;	502	$done->recv;
449		503
450	=head2 IDLE WATCHERS	504	=head2 IDLE WATCHERS
451		505
452	Sometimes there is a need to do something, but it is not so important	506	$w = AnyEvent->idle (cb => <callback>);
453	to do it instantly, but only when there is nothing better to do. This
454	"nothing better to do" is usually defined to be "no other events need
455	attention by the event loop".
456		507
457	Idle watchers ideally get invoked when the event loop has nothing	508	Repeatedly invoke the callback after the process becomes idle, until
458	better to do, just before it would block the process to wait for new	509	either the watcher is destroyed or new events have been detected.
459	events. Instead of blocking, the idle watcher is invoked.
460		510
461	Most event loops unfortunately do not really support idle watchers (only	511	Idle watchers are useful when there is a need to do something, but it
		512	is not so important (or wise) to do it instantly. The callback will be
		513	invoked only when there is "nothing better to do", which is usually
		514	defined as "all outstanding events have been handled and no new events
		515	have been detected". That means that idle watchers ideally get invoked
		516	when the event loop has just polled for new events but none have been
		517	detected. Instead of blocking to wait for more events, the idle watchers
		518	will be invoked.
		519
		520	Unfortunately, most event loops do not really support idle watchers (only
462	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	521	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
463	will simply call the callback "from time to time".	522	will simply call the callback "from time to time".
464		523
465	Example: read lines from STDIN, but only process them when the	524	Example: read lines from STDIN, but only process them when the
466	program is otherwise idle:	525	program is otherwise idle:
…		…
482	});	541	});
483	});	542	});
484		543
485	=head2 CONDITION VARIABLES	544	=head2 CONDITION VARIABLES
486		545
		546	$cv = AnyEvent->condvar;
		547
		548	$cv->send (<list>);
		549	my @res = $cv->recv;
		550
487	If you are familiar with some event loops you will know that all of them	551	If you are familiar with some event loops you will know that all of them
488	require you to run some blocking "loop", "run" or similar function that	552	require you to run some blocking "loop", "run" or similar function that
489	will actively watch for new events and call your callbacks.	553	will actively watch for new events and call your callbacks.
490		554
491	AnyEvent is different, it expects somebody else to run the event loop and	555	AnyEvent is slightly different: it expects somebody else to run the event
492	will only block when necessary (usually when told by the user).	556	loop and will only block when necessary (usually when told by the user).
493		557
494	The instrument to do that is called a "condition variable", so called	558	The instrument to do that is called a "condition variable", so called
495	because they represent a condition that must become true.	559	because they represent a condition that must become true.
496		560
		561	Now is probably a good time to look at the examples further below.
		562
497	Condition variables can be created by calling the C<< AnyEvent->condvar	563	Condition variables can be created by calling the C<< AnyEvent->condvar
498	>> method, usually without arguments. The only argument pair allowed is	564	>> method, usually without arguments. The only argument pair allowed is
499
500	C<cb>, which specifies a callback to be called when the condition variable	565	C<cb>, which specifies a callback to be called when the condition variable
501	becomes true, with the condition variable as the first argument (but not	566	becomes true, with the condition variable as the first argument (but not
502	the results).	567	the results).
503		568
504	After creation, the condition variable is "false" until it becomes "true"	569	After creation, the condition variable is "false" until it becomes "true"
…		…
509	Condition variables are similar to callbacks, except that you can	574	Condition variables are similar to callbacks, except that you can
510	optionally wait for them. They can also be called merge points - points	575	optionally wait for them. They can also be called merge points - points
511	in time where multiple outstanding events have been processed. And yet	576	in time where multiple outstanding events have been processed. And yet
512	another way to call them is transactions - each condition variable can be	577	another way to call them is transactions - each condition variable can be
513	used to represent a transaction, which finishes at some point and delivers	578	used to represent a transaction, which finishes at some point and delivers
514	a result.	579	a result. And yet some people know them as "futures" - a promise to
		580	compute/deliver something that you can wait for.
515		581
516	Condition variables are very useful to signal that something has finished,	582	Condition variables are very useful to signal that something has finished,
517	for example, if you write a module that does asynchronous http requests,	583	for example, if you write a module that does asynchronous http requests,
518	then a condition variable would be the ideal candidate to signal the	584	then a condition variable would be the ideal candidate to signal the
519	availability of results. The user can either act when the callback is	585	availability of results. The user can either act when the callback is
…		…
553	after => 1,	619	after => 1,
554	cb => sub { $result_ready->send },	620	cb => sub { $result_ready->send },
555	);	621	);
556		622
557	# this "blocks" (while handling events) till the callback	623	# this "blocks" (while handling events) till the callback
558	# calls send	624	# calls ->send
559	$result_ready->recv;	625	$result_ready->recv;
560		626
561	Example: wait for a timer, but take advantage of the fact that	627	Example: wait for a timer, but take advantage of the fact that condition
562	condition variables are also code references.	628	variables are also callable directly.
563		629
564	my $done = AnyEvent->condvar;	630	my $done = AnyEvent->condvar;
565	my $delay = AnyEvent->timer (after => 5, cb => $done);	631	my $delay = AnyEvent->timer (after => 5, cb => $done);
566	$done->recv;	632	$done->recv;
567		633
…		…
573		639
574	...	640	...
575		641
576	my @info = $couchdb->info->recv;	642	my @info = $couchdb->info->recv;
577		643
578	And this is how you would just ste a callback to be called whenever the	644	And this is how you would just set a callback to be called whenever the
579	results are available:	645	results are available:
580		646
581	$couchdb->info->cb (sub {	647	$couchdb->info->cb (sub {
582	my @info = $_[0]->recv;	648	my @info = $_[0]->recv;
583	});	649	});
…		…
601	immediately from within send.	667	immediately from within send.
602		668
603	Any arguments passed to the C<send> call will be returned by all	669	Any arguments passed to the C<send> call will be returned by all
604	future C<< ->recv >> calls.	670	future C<< ->recv >> calls.
605		671
606	Condition variables are overloaded so one can call them directly	672	Condition variables are overloaded so one can call them directly (as if
607	(as a code reference). Calling them directly is the same as calling	673	they were a code reference). Calling them directly is the same as calling
608	C<send>. Note, however, that many C-based event loops do not handle	674	C<send>.
609	overloading, so as tempting as it may be, passing a condition variable
610	instead of a callback does not work. Both the pure perl and EV loops
611	support overloading, however, as well as all functions that use perl to
612	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
613	example).
614		675
615	=item $cv->croak ($error)	676	=item $cv->croak ($error)
616		677
617	Similar to send, but causes all call's to C<< ->recv >> to invoke	678	Similar to send, but causes all call's to C<< ->recv >> to invoke
618	C<Carp::croak> with the given error message/object/scalar.	679	C<Carp::croak> with the given error message/object/scalar.
619		680
620	This can be used to signal any errors to the condition variable	681	This can be used to signal any errors to the condition variable
621	user/consumer.	682	user/consumer. Doing it this way instead of calling C<croak> directly
		683	delays the error detetcion, but has the overwhelmign advantage that it
		684	diagnoses the error at the place where the result is expected, and not
		685	deep in some event clalback without connection to the actual code causing
		686	the problem.
622		687
623	=item $cv->begin ([group callback])	688	=item $cv->begin ([group callback])
624		689
625	=item $cv->end	690	=item $cv->end
626		691
…		…
628	one. For example, a function that pings many hosts in parallel might want	693	one. For example, a function that pings many hosts in parallel might want
629	to use a condition variable for the whole process.	694	to use a condition variable for the whole process.
630		695
631	Every call to C<< ->begin >> will increment a counter, and every call to	696	Every call to C<< ->begin >> will increment a counter, and every call to
632	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	697	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
633	>>, the (last) callback passed to C<begin> will be executed. That callback	698	>>, the (last) callback passed to C<begin> will be executed, passing the
634	is I<supposed> to call C<< ->send >>, but that is not required. If no	699	condvar as first argument. That callback is I<supposed> to call C<< ->send
635	callback was set, C<send> will be called without any arguments.	700	>>, but that is not required. If no group callback was set, C<send> will
		701	be called without any arguments.
636		702
637	You can think of C<< $cv->send >> giving you an OR condition (one call	703	You can think of C<< $cv->send >> giving you an OR condition (one call
638	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND	704	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
639	condition (all C<begin> calls must be C<end>'ed before the condvar sends).	705	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
640		706
…		…
667	begung can potentially be zero:	733	begung can potentially be zero:
668		734
669	my $cv = AnyEvent->condvar;	735	my $cv = AnyEvent->condvar;
670		736
671	my %result;	737	my %result;
672	$cv->begin (sub { $cv->send (\%result) });	738	$cv->begin (sub { shift->send (\%result) });
673		739
674	for my $host (@list_of_hosts) {	740	for my $host (@list_of_hosts) {
675	$cv->begin;	741	$cv->begin;
676	ping_host_then_call_callback $host, sub {	742	ping_host_then_call_callback $host, sub {
677	$result{$host} = ...;	743	$result{$host} = ...;
…		…
722	function will call C<croak>.	788	function will call C<croak>.
723		789
724	In list context, all parameters passed to C<send> will be returned,	790	In list context, all parameters passed to C<send> will be returned,
725	in scalar context only the first one will be returned.	791	in scalar context only the first one will be returned.
726		792
		793	Note that doing a blocking wait in a callback is not supported by any
		794	event loop, that is, recursive invocation of a blocking C<< ->recv
		795	>> is not allowed, and the C<recv> call will C<croak> if such a
		796	condition is detected. This condition can be slightly loosened by using
		797	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		798	any thread that doesn't run the event loop itself.
		799
727	Not all event models support a blocking wait - some die in that case	800	Not all event models support a blocking wait - some die in that case
728	(programs might want to do that to stay interactive), so I<if you are	801	(programs might want to do that to stay interactive), so I<if you are
729	using this from a module, never require a blocking wait>, but let the	802	using this from a module, never require a blocking wait>. Instead, let the
730	caller decide whether the call will block or not (for example, by coupling	803	caller decide whether the call will block or not (for example, by coupling
731	condition variables with some kind of request results and supporting	804	condition variables with some kind of request results and supporting
732	callbacks so the caller knows that getting the result will not block,	805	callbacks so the caller knows that getting the result will not block,
733	while still supporting blocking waits if the caller so desires).	806	while still supporting blocking waits if the caller so desires).
734		807
735	Another reason I<never> to C<< ->recv >> in a module is that you cannot
736	sensibly have two C<< ->recv >>'s in parallel, as that would require
737	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
738	can supply.
739
740	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
741	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
742	versions and also integrates coroutines into AnyEvent, making blocking
743	C<< ->recv >> calls perfectly safe as long as they are done from another
744	coroutine (one that doesn't run the event loop).
745
746	You can ensure that C<< -recv >> never blocks by setting a callback and	808	You can ensure that C<< -recv >> never blocks by setting a callback and
747	only calling C<< ->recv >> from within that callback (or at a later	809	only calling C<< ->recv >> from within that callback (or at a later
748	time). This will work even when the event loop does not support blocking	810	time). This will work even when the event loop does not support blocking
749	waits otherwise.	811	waits otherwise.
750		812
…		…
756	=item $cb = $cv->cb ($cb->($cv))	818	=item $cb = $cv->cb ($cb->($cv))
757		819
758	This is a mutator function that returns the callback set and optionally	820	This is a mutator function that returns the callback set and optionally
759	replaces it before doing so.	821	replaces it before doing so.
760		822
761	The callback will be called when the condition becomes "true", i.e. when	823	The callback will be called when the condition becomes (or already was)
762	C<send> or C<croak> are called, with the only argument being the condition	824	"true", i.e. when C<send> or C<croak> are called (or were called), with
763	variable itself. Calling C<recv> inside the callback or at any later time	825	the only argument being the condition variable itself. Calling C<recv>
764	is guaranteed not to block.	826	inside the callback or at any later time is guaranteed not to block.
765		827
766	=back	828	=back
767		829
		830	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		831
		832	The available backend classes are (every class has its own manpage):
		833
		834	=over 4
		835
		836	=item Backends that are autoprobed when no other event loop can be found.
		837
		838	EV is the preferred backend when no other event loop seems to be in
		839	use. If EV is not installed, then AnyEvent will fall back to its own
		840	pure-perl implementation, which is available everywhere as it comes with
		841	AnyEvent itself.
		842
		843	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		844	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		845
		846	=item Backends that are transparently being picked up when they are used.
		847
		848	These will be used when they are currently loaded when the first watcher
		849	is created, in which case it is assumed that the application is using
		850	them. This means that AnyEvent will automatically pick the right backend
		851	when the main program loads an event module before anything starts to
		852	create watchers. Nothing special needs to be done by the main program.
		853
		854	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		855	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		856	AnyEvent::Impl::Tk based on Tk, very broken.
		857	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		858	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		859	AnyEvent::Impl::Irssi used when running within irssi.
		860
		861	=item Backends with special needs.
		862
		863	Qt requires the Qt::Application to be instantiated first, but will
		864	otherwise be picked up automatically. As long as the main program
		865	instantiates the application before any AnyEvent watchers are created,
		866	everything should just work.
		867
		868	AnyEvent::Impl::Qt based on Qt.
		869
		870	Support for IO::Async can only be partial, as it is too broken and
		871	architecturally limited to even support the AnyEvent API. It also
		872	is the only event loop that needs the loop to be set explicitly, so
		873	it can only be used by a main program knowing about AnyEvent. See
		874	L<AnyEvent::Impl::Async> for the gory details.
		875
		876	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		877
		878	=item Event loops that are indirectly supported via other backends.
		879
		880	Some event loops can be supported via other modules:
		881
		882	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		883
		884	B<WxWidgets> has no support for watching file handles. However, you can
		885	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		886	polls 20 times per second, which was considered to be too horrible to even
		887	consider for AnyEvent.
		888
		889	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		890	backend, so it can be supported through POE.
		891
		892	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		893	load L<POE> when detecting them, in the hope that POE will pick them up,
		894	in which case everything will be automatic.
		895
		896	=back
		897
768	=head1 GLOBAL VARIABLES AND FUNCTIONS	898	=head1 GLOBAL VARIABLES AND FUNCTIONS
769		899
		900	These are not normally required to use AnyEvent, but can be useful to
		901	write AnyEvent extension modules.
		902
770	=over 4	903	=over 4
771		904
772	=item $AnyEvent::MODEL	905	=item $AnyEvent::MODEL
773		906
774	Contains C<undef> until the first watcher is being created. Then it	907	Contains C<undef> until the first watcher is being created, before the
		908	backend has been autodetected.
		909
775	contains the event model that is being used, which is the name of the	910	Afterwards it contains the event model that is being used, which is the
776	Perl class implementing the model. This class is usually one of the	911	name of the Perl class implementing the model. This class is usually one
777	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	912	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
778	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	913	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
779		914	will be C<urxvt::anyevent>).
780	The known classes so far are:
781
782	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
783	AnyEvent::Impl::Event based on Event, second best choice.
784	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
785	AnyEvent::Impl::Glib based on Glib, third-best choice.
786	AnyEvent::Impl::Tk based on Tk, very bad choice.
787	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
788	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
789	AnyEvent::Impl::POE based on POE, not generic enough for full support.
790
791	# warning, support for IO::Async is only partial, as it is too broken
792	# and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
793	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
794
795	There is no support for WxWidgets, as WxWidgets has no support for
796	watching file handles. However, you can use WxWidgets through the
797	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
798	second, which was considered to be too horrible to even consider for
799	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
800	it's adaptor.
801
802	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
803	autodetecting them.
804		915
805	=item AnyEvent::detect	916	=item AnyEvent::detect
806		917
807	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	918	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
808	if necessary. You should only call this function right before you would	919	if necessary. You should only call this function right before you would
809	have created an AnyEvent watcher anyway, that is, as late as possible at	920	have created an AnyEvent watcher anyway, that is, as late as possible at
810	runtime.	921	runtime, and not e.g. while initialising of your module.
		922
		923	If you need to do some initialisation before AnyEvent watchers are
		924	created, use C<post_detect>.
811		925
812	=item $guard = AnyEvent::post_detect { BLOCK }	926	=item $guard = AnyEvent::post_detect { BLOCK }
813		927
814	Arranges for the code block to be executed as soon as the event model is	928	Arranges for the code block to be executed as soon as the event model is
815	autodetected (or immediately if this has already happened).	929	autodetected (or immediately if this has already happened).
816		930
		931	The block will be executed I<after> the actual backend has been detected
		932	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		933	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		934	other initialisations - see the sources of L<AnyEvent::Strict> or
		935	L<AnyEvent::AIO> to see how this is used.
		936
		937	The most common usage is to create some global watchers, without forcing
		938	event module detection too early, for example, L<AnyEvent::AIO> creates
		939	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		940	avoid autodetecting the event module at load time.
		941
817	If called in scalar or list context, then it creates and returns an object	942	If called in scalar or list context, then it creates and returns an object
818	that automatically removes the callback again when it is destroyed. See	943	that automatically removes the callback again when it is destroyed (or
		944	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
819	L<Coro::BDB> for a case where this is useful.	945	a case where this is useful.
		946
		947	Example: Create a watcher for the IO::AIO module and store it in
		948	C<$WATCHER>. Only do so after the event loop is initialised, though.
		949
		950	our WATCHER;
		951
		952	my $guard = AnyEvent::post_detect {
		953	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		954	};
		955
		956	# the ||= is important in case post_detect immediately runs the block,
		957	# as to not clobber the newly-created watcher. assigning both watcher and
		958	# post_detect guard to the same variable has the advantage of users being
		959	# able to just C<undef $WATCHER> if the watcher causes them grief.
		960
		961	$WATCHER ||= $guard;
820		962
821	=item @AnyEvent::post_detect	963	=item @AnyEvent::post_detect
822		964
823	If there are any code references in this array (you can C<push> to it	965	If there are any code references in this array (you can C<push> to it
824	before or after loading AnyEvent), then they will called directly after	966	before or after loading AnyEvent), then they will called directly after
825	the event loop has been chosen.	967	the event loop has been chosen.
826		968
827	You should check C<$AnyEvent::MODEL> before adding to this array, though:	969	You should check C<$AnyEvent::MODEL> before adding to this array, though:
828	if it contains a true value then the event loop has already been detected,	970	if it is defined then the event loop has already been detected, and the
829	and the array will be ignored.	971	array will be ignored.
830		972
831	Best use C<AnyEvent::post_detect { BLOCK }> instead.	973	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		974	it, as it takes care of these details.
		975
		976	This variable is mainly useful for modules that can do something useful
		977	when AnyEvent is used and thus want to know when it is initialised, but do
		978	not need to even load it by default. This array provides the means to hook
		979	into AnyEvent passively, without loading it.
		980
		981	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		982	together, you could put this into Coro (this is the actual code used by
		983	Coro to accomplish this):
		984
		985	if (defined $AnyEvent::MODEL) {
		986	# AnyEvent already initialised, so load Coro::AnyEvent
		987	require Coro::AnyEvent;
		988	} else {
		989	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		990	# as soon as it is
		991	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		992	}
832		993
833	=back	994	=back
834		995
835	=head1 WHAT TO DO IN A MODULE	996	=head1 WHAT TO DO IN A MODULE
836		997
…		…
891		1052
892		1053
893	=head1 OTHER MODULES	1054	=head1 OTHER MODULES
894		1055
895	The following is a non-exhaustive list of additional modules that use	1056	The following is a non-exhaustive list of additional modules that use
896	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1057	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
897	in the same program. Some of the modules come with AnyEvent, some are	1058	modules and other event loops in the same program. Some of the modules
898	available via CPAN.	1059	come with AnyEvent, most are available via CPAN.
899		1060
900	=over 4	1061	=over 4
901		1062
902	=item L<AnyEvent::Util>	1063	=item L<AnyEvent::Util>
903		1064
…		…
912		1073
913	=item L<AnyEvent::Handle>	1074	=item L<AnyEvent::Handle>
914		1075
915	Provide read and write buffers, manages watchers for reads and writes,	1076	Provide read and write buffers, manages watchers for reads and writes,
916	supports raw and formatted I/O, I/O queued and fully transparent and	1077	supports raw and formatted I/O, I/O queued and fully transparent and
917	non-blocking SSL/TLS.	1078	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
918		1079
919	=item L<AnyEvent::DNS>	1080	=item L<AnyEvent::DNS>
920		1081
921	Provides rich asynchronous DNS resolver capabilities.	1082	Provides rich asynchronous DNS resolver capabilities.
922		1083
…		…
950		1111
951	=item L<AnyEvent::GPSD>	1112	=item L<AnyEvent::GPSD>
952		1113
953	A non-blocking interface to gpsd, a daemon delivering GPS information.	1114	A non-blocking interface to gpsd, a daemon delivering GPS information.
954		1115
		1116	=item L<AnyEvent::IRC>
		1117
		1118	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1119
		1120	=item L<AnyEvent::XMPP>
		1121
		1122	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1123	Net::XMPP2>.
		1124
955	=item L<AnyEvent::IGS>	1125	=item L<AnyEvent::IGS>
956		1126
957	A non-blocking interface to the Internet Go Server protocol (used by	1127	A non-blocking interface to the Internet Go Server protocol (used by
958	L<App::IGS>).	1128	L<App::IGS>).
959		1129
960	=item L<AnyEvent::IRC>
961
962	AnyEvent based IRC client module family (replacing the older Net::IRC3).
963
964	=item L<Net::XMPP2>
965
966	AnyEvent based XMPP (Jabber protocol) module family.
967
968	=item L<Net::FCP>	1130	=item L<Net::FCP>
969		1131
970	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1132	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
971	of AnyEvent.	1133	of AnyEvent.
972		1134
…		…
976		1138
977	=item L<Coro>	1139	=item L<Coro>
978		1140
979	Has special support for AnyEvent via L<Coro::AnyEvent>.	1141	Has special support for AnyEvent via L<Coro::AnyEvent>.
980		1142
981	=item L<IO::Lambda>
982
983	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
984
985	=back	1143	=back
986		1144
987	=cut	1145	=cut
988		1146
989	package AnyEvent;	1147	package AnyEvent;
990		1148
991	no warnings;	1149	# basically a tuned-down version of common::sense
992	use strict qw(vars subs);	1150	sub common_sense {
		1151	# from common:.sense 1.0
		1152	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
		1153	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1154	$^H |= 0x00000600;
		1155	}
993		1156
		1157	BEGIN { AnyEvent::common_sense }
		1158
994	use Carp;	1159	use Carp ();
995		1160
996	our $VERSION = 4.8;	1161	our $VERSION = '5.24';
997	our $MODEL;	1162	our $MODEL;
998		1163
999	our $AUTOLOAD;	1164	our $AUTOLOAD;
1000	our @ISA;	1165	our @ISA;
1001		1166
1002	our @REGISTRY;	1167	our @REGISTRY;
1003		1168
1004	our $WIN32;	1169	our $VERBOSE;
1005		1170
1006	BEGIN {	1171	BEGIN {
		1172	eval "sub CYGWIN(){" . (($^O =~ /cygwin/i) *1) . "}";
1007	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1173	eval "sub WIN32 (){" . (($^O =~ /mswin32/i)*1) . "}";
1008	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1174	eval "sub TAINT (){" . (${^TAINT} *1) . "}";
1009		1175
1010	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1176	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1011	if ${^TAINT};	1177	if ${^TAINT};
1012	}
1013		1178
1014	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1179	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1180
		1181	}
		1182
		1183	our $MAX_SIGNAL_LATENCY = 10;
1015		1184
1016	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1185	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
1017		1186
1018	{	1187	{
1019	my $idx;	1188	my $idx;
…		…
1021	for reverse split /\s*,\s*/,	1190	for reverse split /\s*,\s*/,
1022	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1191	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1023	}	1192	}
1024		1193
1025	my @models = (	1194	my @models = (
1026	[EV:: => AnyEvent::Impl::EV::],	1195	[EV:: => AnyEvent::Impl::EV:: , 1],
1027	[Event:: => AnyEvent::Impl::Event::],
1028	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1196	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1029	# everything below here will not be autoprobed	1197	# everything below here will not (normally) be autoprobed
1030	# as the pureperl backend should work everywhere	1198	# as the pureperl backend should work everywhere
1031	# and is usually faster	1199	# and is usually faster
		1200	[Event:: => AnyEvent::Impl::Event::, 1],
		1201	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1202	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1203	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1032	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1204	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1033	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
1034	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1035	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1205	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1036	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1206	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1037	[Wx:: => AnyEvent::Impl::POE::],	1207	[Wx:: => AnyEvent::Impl::POE::],
1038	[Prima:: => AnyEvent::Impl::POE::],	1208	[Prima:: => AnyEvent::Impl::POE::],
1039	# IO::Async is just too broken - we would need workaorunds for its	1209	# IO::Async is just too broken - we would need workarounds for its
1040	# byzantine signal and broken child handling, among others.	1210	# byzantine signal and broken child handling, among others.
1041	# IO::Async is rather hard to detect, as it doesn't have any	1211	# IO::Async is rather hard to detect, as it doesn't have any
1042	# obvious default class.	1212	# obvious default class.
1043	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program	1213	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1044	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program	1214	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1045	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program	1215	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1216	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1046	);	1217	);
1047		1218
1048	our %method = map +($_ => 1),	1219	our %method = map +($_ => 1),
1049	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1220	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
1050		1221
…		…
1054	my ($cb) = @_;	1225	my ($cb) = @_;
1055		1226
1056	if ($MODEL) {	1227	if ($MODEL) {
1057	$cb->();	1228	$cb->();
1058		1229
1059	1	1230	undef
1060	} else {	1231	} else {
1061	push @post_detect, $cb;	1232	push @post_detect, $cb;
1062		1233
1063	defined wantarray	1234	defined wantarray
1064	? bless \$cb, "AnyEvent::Util::postdetect"	1235	? bless \$cb, "AnyEvent::Util::postdetect"
…		…
1070	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1241	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1071	}	1242	}
1072		1243
1073	sub detect() {	1244	sub detect() {
1074	unless ($MODEL) {	1245	unless ($MODEL) {
1075	no strict 'refs';
1076	local $SIG{__DIE__};	1246	local $SIG{__DIE__};
1077		1247
1078	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1248	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1079	my $model = "AnyEvent::Impl::$1";	1249	my $model = "AnyEvent::Impl::$1";
1080	if (eval "require $model") {	1250	if (eval "require $model") {
1081	$MODEL = $model;	1251	$MODEL = $model;
1082	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1252	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1083	} else {	1253	} else {
1084	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1254	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1085	}	1255	}
1086	}	1256	}
1087		1257
1088	# check for already loaded models	1258	# check for already loaded models
1089	unless ($MODEL) {	1259	unless ($MODEL) {
1090	for (@REGISTRY, @models) {	1260	for (@REGISTRY, @models) {
1091	my ($package, $model) = @$_;	1261	my ($package, $model) = @$_;
1092	if (${"$package\::VERSION"} > 0) {	1262	if (${"$package\::VERSION"} > 0) {
1093	if (eval "require $model") {	1263	if (eval "require $model") {
1094	$MODEL = $model;	1264	$MODEL = $model;
1095	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1265	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1096	last;	1266	last;
1097	}	1267	}
1098	}	1268	}
1099	}	1269	}
1100		1270
1101	unless ($MODEL) {	1271	unless ($MODEL) {
1102	# try to load a model	1272	# try to autoload a model
1103
1104	for (@REGISTRY, @models) {	1273	for (@REGISTRY, @models) {
1105	my ($package, $model) = @$_;	1274	my ($package, $model, $autoload) = @$_;
		1275	if (
		1276	$autoload
1106	if (eval "require $package"	1277	and eval "require $package"
1107	and ${"$package\::VERSION"} > 0	1278	and ${"$package\::VERSION"} > 0
1108	and eval "require $model") {	1279	and eval "require $model"
		1280	) {
1109	$MODEL = $model;	1281	$MODEL = $model;
1110	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1282	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1111	last;	1283	last;
1112	}	1284	}
1113	}	1285	}
1114		1286
1115	$MODEL	1287	$MODEL
…		…
1131		1303
1132	sub AUTOLOAD {	1304	sub AUTOLOAD {
1133	(my $func = $AUTOLOAD) =~ s/.*://;	1305	(my $func = $AUTOLOAD) =~ s/.*://;
1134		1306
1135	$method{$func}	1307	$method{$func}
1136	or croak "$func: not a valid method for AnyEvent objects";	1308	or Carp::croak "$func: not a valid method for AnyEvent objects";
1137		1309
1138	detect unless $MODEL;	1310	detect unless $MODEL;
1139		1311
1140	my $class = shift;	1312	my $class = shift;
1141	$class->$func (@_);	1313	$class->$func (@_);
…		…
1146	# allow only one watcher per fd, so we dup it to get a different one).	1318	# allow only one watcher per fd, so we dup it to get a different one).
1147	sub _dupfh($$;$$) {	1319	sub _dupfh($$;$$) {
1148	my ($poll, $fh, $r, $w) = @_;	1320	my ($poll, $fh, $r, $w) = @_;
1149		1321
1150	# cygwin requires the fh mode to be matching, unix doesn't	1322	# cygwin requires the fh mode to be matching, unix doesn't
1151	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1323	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1152	: $poll eq "w" ? ($w, ">")
1153	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1154		1324
1155	open my $fh2, "$mode&" . fileno $fh	1325	open my $fh2, $mode, $fh
1156	or die "cannot dup() filehandle: $!,";	1326	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1157		1327
1158	# we assume CLOEXEC is already set by perl in all important cases	1328	# we assume CLOEXEC is already set by perl in all important cases
1159		1329
1160	($fh2, $rw)	1330	($fh2, $rw)
1161	}	1331	}
1162		1332
		1333	=head1 SIMPLIFIED AE API
		1334
		1335	Starting with version 5.0, AnyEvent officially supports a second, much
		1336	simpler, API that is designed to reduce the calling, typing and memory
		1337	overhead.
		1338
		1339	See the L<AE> manpage for details.
		1340
		1341	=cut
		1342
		1343	package AE;
		1344
		1345	our $VERSION = $AnyEvent::VERSION;
		1346
		1347	sub io($$$) {
		1348	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1349	}
		1350
		1351	sub timer($$$) {
		1352	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1353	}
		1354
		1355	sub signal($$) {
		1356	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1357	}
		1358
		1359	sub child($$) {
		1360	AnyEvent->child (pid => $_[0], cb => $_[1])
		1361	}
		1362
		1363	sub idle($) {
		1364	AnyEvent->idle (cb => $_[0])
		1365	}
		1366
		1367	sub cv(;&) {
		1368	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1369	}
		1370
		1371	sub now() {
		1372	AnyEvent->now
		1373	}
		1374
		1375	sub now_update() {
		1376	AnyEvent->now_update
		1377	}
		1378
		1379	sub time() {
		1380	AnyEvent->time
		1381	}
		1382
1163	package AnyEvent::Base;	1383	package AnyEvent::Base;
1164		1384
1165	# default implementations for many methods	1385	# default implementations for many methods
1166		1386
1167	BEGIN {	1387	sub _time() {
		1388	# probe for availability of Time::HiRes
1168	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1389	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1390	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1169	*_time = \&Time::HiRes::time;	1391	*_time = \&Time::HiRes::time;
1170	# if (eval "use POSIX (); (POSIX::times())...	1392	# if (eval "use POSIX (); (POSIX::times())...
1171	} else {	1393	} else {
		1394	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1172	*_time = sub { time }; # epic fail	1395	*_time = sub { time }; # epic fail
1173	}	1396	}
		1397
		1398	&_time
1174	}	1399	}
1175		1400
1176	sub time { _time }	1401	sub time { _time }
1177	sub now { _time }	1402	sub now { _time }
1178	sub now_update { }	1403	sub now_update { }
…		…
1183	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1408	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1184	}	1409	}
1185		1410
1186	# default implementation for ->signal	1411	# default implementation for ->signal
1187		1412
		1413	our $HAVE_ASYNC_INTERRUPT;
		1414
		1415	sub _have_async_interrupt() {
		1416	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1417	&& eval "use Async::Interrupt 1.02 (); 1")
		1418	unless defined $HAVE_ASYNC_INTERRUPT;
		1419
		1420	$HAVE_ASYNC_INTERRUPT
		1421	}
		1422
1188	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1423	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1424	our (%SIG_ASY, %SIG_ASY_W);
		1425	our ($SIG_COUNT, $SIG_TW);
1189		1426
1190	sub _signal_exec {	1427	sub _signal_exec {
		1428	$HAVE_ASYNC_INTERRUPT
		1429	? $SIGPIPE_R->drain
1191	sysread $SIGPIPE_R, my $dummy, 4;	1430	: sysread $SIGPIPE_R, (my $dummy), 9;
1192		1431
1193	while (%SIG_EV) {	1432	while (%SIG_EV) {
1194	for (keys %SIG_EV) {	1433	for (keys %SIG_EV) {
1195	delete $SIG_EV{$_};	1434	delete $SIG_EV{$_};
1196	$_->() for values %{ $SIG_CB{$_} || {} };	1435	$_->() for values %{ $SIG_CB{$_} || {} };
1197	}	1436	}
1198	}	1437	}
1199	}	1438	}
1200		1439
		1440	# install a dummy wakeup watcher to reduce signal catching latency
		1441	sub _sig_add() {
		1442	unless ($SIG_COUNT++) {
		1443	# try to align timer on a full-second boundary, if possible
		1444	my $NOW = AE::now;
		1445
		1446	$SIG_TW = AE::timer
		1447	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1448	$MAX_SIGNAL_LATENCY,
		1449	sub { } # just for the PERL_ASYNC_CHECK
		1450	;
		1451	}
		1452	}
		1453
		1454	sub _sig_del {
		1455	undef $SIG_TW
		1456	unless --$SIG_COUNT;
		1457	}
		1458
		1459	our $_sig_name_init; $_sig_name_init = sub {
		1460	eval q{ # poor man's autoloading
		1461	undef $_sig_name_init;
		1462
		1463	if (_have_async_interrupt) {
		1464	*sig2num = \&Async::Interrupt::sig2num;
		1465	*sig2name = \&Async::Interrupt::sig2name;
		1466	} else {
		1467	require Config;
		1468
		1469	my %signame2num;
		1470	@signame2num{ split ' ', $Config::Config{sig_name} }
		1471	= split ' ', $Config::Config{sig_num};
		1472
		1473	my @signum2name;
		1474	@signum2name[values %signame2num] = keys %signame2num;
		1475
		1476	*sig2num = sub($) {
		1477	$_[0] > 0 ? shift : $signame2num{+shift}
		1478	};
		1479	*sig2name = sub ($) {
		1480	$_[0] > 0 ? $signum2name[+shift] : shift
		1481	};
		1482	}
		1483	};
		1484	die if $@;
		1485	};
		1486
		1487	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1488	sub sig2name($) { &$_sig_name_init; &sig2name }
		1489
1201	sub signal {	1490	sub signal {
1202	my (undef, %arg) = @_;	1491	eval q{ # poor man's autoloading {}
		1492	# probe for availability of Async::Interrupt
		1493	if (_have_async_interrupt) {
		1494	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1203		1495
1204	unless ($SIGPIPE_R) {	1496	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1205	require Fcntl;	1497	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1206		1498
1207	if (AnyEvent::WIN32) {
1208	require AnyEvent::Util;
1209
1210	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1211	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1212	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1213	} else {	1499	} else {
		1500	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1501
		1502	require Fcntl;
		1503
		1504	if (AnyEvent::WIN32) {
		1505	require AnyEvent::Util;
		1506
		1507	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1508	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1509	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1510	} else {
1214	pipe $SIGPIPE_R, $SIGPIPE_W;	1511	pipe $SIGPIPE_R, $SIGPIPE_W;
1215	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1512	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1216	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1513	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1217		1514
1218	# not strictly required, as $^F is normally 2, but let's make sure...	1515	# not strictly required, as $^F is normally 2, but let's make sure...
1219	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1516	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1220	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1517	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1518	}
		1519
		1520	$SIGPIPE_R
		1521	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1522
		1523	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1221	}	1524	}
1222		1525
1223	$SIGPIPE_R	1526	*signal = sub {
1224	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1527	my (undef, %arg) = @_;
1225		1528
1226	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1227	}
1228
1229	my $signal = uc $arg{signal}	1529	my $signal = uc $arg{signal}
1230	or Carp::croak "required option 'signal' is missing";	1530	or Carp::croak "required option 'signal' is missing";
1231		1531
		1532	if ($HAVE_ASYNC_INTERRUPT) {
		1533	# async::interrupt
		1534
		1535	$signal = sig2num $signal;
1232	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1536	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1537
		1538	$SIG_ASY{$signal} ||= new Async::Interrupt
		1539	cb => sub { undef $SIG_EV{$signal} },
		1540	signal => $signal,
		1541	pipe => [$SIGPIPE_R->filenos],
		1542	pipe_autodrain => 0,
		1543	;
		1544
		1545	} else {
		1546	# pure perl
		1547
		1548	# AE::Util has been loaded in signal
		1549	$signal = sig2name $signal;
		1550	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1551
1233	$SIG{$signal} ||= sub {	1552	$SIG{$signal} ||= sub {
1234	local $!;	1553	local $!;
1235	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1554	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1236	undef $SIG_EV{$signal};	1555	undef $SIG_EV{$signal};
		1556	};
		1557
		1558	# can't do signal processing without introducing races in pure perl,
		1559	# so limit the signal latency.
		1560	_sig_add;
		1561	}
		1562
		1563	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1564	};
		1565
		1566	*AnyEvent::Base::signal::DESTROY = sub {
		1567	my ($signal, $cb) = @{$_[0]};
		1568
		1569	_sig_del;
		1570
		1571	delete $SIG_CB{$signal}{$cb};
		1572
		1573	$HAVE_ASYNC_INTERRUPT
		1574	? delete $SIG_ASY{$signal}
		1575	: # delete doesn't work with older perls - they then
		1576	# print weird messages, or just unconditionally exit
		1577	# instead of getting the default action.
		1578	undef $SIG{$signal}
		1579	unless keys %{ $SIG_CB{$signal} };
		1580	};
1237	};	1581	};
1238		1582	die if $@;
1239	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1583	&signal
1240	}
1241
1242	sub AnyEvent::Base::signal::DESTROY {
1243	my ($signal, $cb) = @{$_[0]};
1244
1245	delete $SIG_CB{$signal}{$cb};
1246
1247	# delete doesn't work with older perls - they then
1248	# print weird messages, or just unconditionally exit
1249	# instead of getting the default action.
1250	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1251	}	1584	}
1252		1585
1253	# default implementation for ->child	1586	# default implementation for ->child
1254		1587
1255	our %PID_CB;	1588	our %PID_CB;
1256	our $CHLD_W;	1589	our $CHLD_W;
1257	our $CHLD_DELAY_W;	1590	our $CHLD_DELAY_W;
1258	our $WNOHANG;	1591	our $WNOHANG;
1259		1592
		1593	sub _emit_childstatus($$) {
		1594	my (undef, $rpid, $rstatus) = @_;
		1595
		1596	$_->($rpid, $rstatus)
		1597	for values %{ $PID_CB{$rpid} || {} },
		1598	values %{ $PID_CB{0} || {} };
		1599	}
		1600
1260	sub _sigchld {	1601	sub _sigchld {
		1602	my $pid;
		1603
		1604	AnyEvent->_emit_childstatus ($pid, $?)
1261	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1605	while ($pid = waitpid -1, $WNOHANG) > 0;
1262	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),
1263	(values %{ $PID_CB{0} || {} });
1264	}
1265	}	1606	}
1266		1607
1267	sub child {	1608	sub child {
1268	my (undef, %arg) = @_;	1609	my (undef, %arg) = @_;
1269		1610
1270	defined (my $pid = $arg{pid} + 0)	1611	defined (my $pid = $arg{pid} + 0)
1271	or Carp::croak "required option 'pid' is missing";	1612	or Carp::croak "required option 'pid' is missing";
1272		1613
1273	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1614	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1274		1615
		1616	# WNOHANG is almost cetrainly 1 everywhere
		1617	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1618	? 1
1275	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1619	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1276		1620
1277	unless ($CHLD_W) {	1621	unless ($CHLD_W) {
1278	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1622	$CHLD_W = AE::signal CHLD => \&_sigchld;
1279	# child could be a zombie already, so make at least one round	1623	# child could be a zombie already, so make at least one round
1280	&_sigchld;	1624	&_sigchld;
1281	}	1625	}
1282		1626
1283	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1627	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
…		…
1309	# never use more then 50% of the time for the idle watcher,	1653	# never use more then 50% of the time for the idle watcher,
1310	# within some limits	1654	# within some limits
1311	$w = 0.0001 if $w < 0.0001;	1655	$w = 0.0001 if $w < 0.0001;
1312	$w = 5 if $w > 5;	1656	$w = 5 if $w > 5;
1313		1657
1314	$w = AnyEvent->timer (after => $w, cb => $rcb);	1658	$w = AE::timer $w, 0, $rcb;
1315	} else {	1659	} else {
1316	# clean up...	1660	# clean up...
1317	undef $w;	1661	undef $w;
1318	undef $rcb;	1662	undef $rcb;
1319	}	1663	}
1320	};	1664	};
1321		1665
1322	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1666	$w = AE::timer 0.05, 0, $rcb;
1323		1667
1324	bless \\$cb, "AnyEvent::Base::idle"	1668	bless \\$cb, "AnyEvent::Base::idle"
1325	}	1669	}
1326		1670
1327	sub AnyEvent::Base::idle::DESTROY {	1671	sub AnyEvent::Base::idle::DESTROY {
…		…
1332		1676
1333	our @ISA = AnyEvent::CondVar::Base::;	1677	our @ISA = AnyEvent::CondVar::Base::;
1334		1678
1335	package AnyEvent::CondVar::Base;	1679	package AnyEvent::CondVar::Base;
1336		1680
1337	use overload	1681	#use overload
1338	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1682	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1339	fallback => 1;	1683	# fallback => 1;
		1684
		1685	# save 300+ kilobytes by dirtily hardcoding overloading
		1686	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1687	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1688	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1689	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1690
		1691	our $WAITING;
1340		1692
1341	sub _send {	1693	sub _send {
1342	# nop	1694	# nop
1343	}	1695	}
1344		1696
…		…
1357	sub ready {	1709	sub ready {
1358	$_[0]{_ae_sent}	1710	$_[0]{_ae_sent}
1359	}	1711	}
1360		1712
1361	sub _wait {	1713	sub _wait {
		1714	$WAITING
		1715	and !$_[0]{_ae_sent}
		1716	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1717
		1718	local $WAITING = 1;
1362	AnyEvent->one_event while !$_[0]{_ae_sent};	1719	AnyEvent->one_event while !$_[0]{_ae_sent};
1363	}	1720	}
1364		1721
1365	sub recv {	1722	sub recv {
1366	$_[0]->_wait;	1723	$_[0]->_wait;
…		…
1368	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1725	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1369	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1726	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1370	}	1727	}
1371		1728
1372	sub cb {	1729	sub cb {
1373	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1730	my $cv = shift;
		1731
		1732	@_
		1733	and $cv->{_ae_cb} = shift
		1734	and $cv->{_ae_sent}
		1735	and (delete $cv->{_ae_cb})->($cv);
		1736
1374	$_[0]{_ae_cb}	1737	$cv->{_ae_cb}
1375	}	1738	}
1376		1739
1377	sub begin {	1740	sub begin {
1378	++$_[0]{_ae_counter};	1741	++$_[0]{_ae_counter};
1379	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1742	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1428	C<PERL_ANYEVENT_MODEL>.	1791	C<PERL_ANYEVENT_MODEL>.
1429		1792
1430	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1793	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1431	model it chooses.	1794	model it chooses.
1432		1795
		1796	When set to C<8> or higher, then AnyEvent will report extra information on
		1797	which optional modules it loads and how it implements certain features.
		1798
1433	=item C<PERL_ANYEVENT_STRICT>	1799	=item C<PERL_ANYEVENT_STRICT>
1434		1800
1435	AnyEvent does not do much argument checking by default, as thorough	1801	AnyEvent does not do much argument checking by default, as thorough
1436	argument checking is very costly. Setting this variable to a true value	1802	argument checking is very costly. Setting this variable to a true value
1437	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1803	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1438	check the arguments passed to most method calls. If it finds any problems,	1804	check the arguments passed to most method calls. If it finds any problems,
1439	it will croak.	1805	it will croak.
1440		1806
1441	In other words, enables "strict" mode.	1807	In other words, enables "strict" mode.
1442		1808
1443	Unlike C<use strict>, it is definitely recommended to keep it off in	1809	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1444	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1810	>>, it is definitely recommended to keep it off in production. Keeping
1445	developing programs can be very useful, however.	1811	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1812	can be very useful, however.
1446		1813
1447	=item C<PERL_ANYEVENT_MODEL>	1814	=item C<PERL_ANYEVENT_MODEL>
1448		1815
1449	This can be used to specify the event model to be used by AnyEvent, before	1816	This can be used to specify the event model to be used by AnyEvent, before
1450	auto detection and -probing kicks in. It must be a string consisting	1817	auto detection and -probing kicks in. It must be a string consisting
…		…
1512		1879
1513	When neither C<ca_file> nor C<ca_path> was specified during	1880	When neither C<ca_file> nor C<ca_path> was specified during
1514	L<AnyEvent::TLS> context creation, and either of these environment	1881	L<AnyEvent::TLS> context creation, and either of these environment
1515	variables exist, they will be used to specify CA certificate locations	1882	variables exist, they will be used to specify CA certificate locations
1516	instead of a system-dependent default.	1883	instead of a system-dependent default.
		1884
		1885	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1886
		1887	When these are set to C<1>, then the respective modules are not
		1888	loaded. Mostly good for testing AnyEvent itself.
1517		1889
1518	=back	1890	=back
1519		1891
1520	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1892	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1521		1893
…		…
1579	warn "read: $input\n"; # output what has been read	1951	warn "read: $input\n"; # output what has been read
1580	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1952	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1581	},	1953	},
1582	);	1954	);
1583		1955
1584	my $time_watcher; # can only be used once
1585
1586	sub new_timer {
1587	$timer = AnyEvent->timer (after => 1, cb => sub {	1956	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1588	warn "timeout\n"; # print 'timeout' about every second	1957	warn "timeout\n"; # print 'timeout' at most every second
1589	&new_timer; # and restart the time
1590	});	1958	});
1591	}
1592
1593	new_timer; # create first timer
1594		1959
1595	$cv->recv; # wait until user enters /^q/i	1960	$cv->recv; # wait until user enters /^q/i
1596		1961
1597	=head1 REAL-WORLD EXAMPLE	1962	=head1 REAL-WORLD EXAMPLE
1598		1963
…		…
1729	through AnyEvent. The benchmark creates a lot of timers (with a zero	2094	through AnyEvent. The benchmark creates a lot of timers (with a zero
1730	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2095	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1731	which it is), lets them fire exactly once and destroys them again.	2096	which it is), lets them fire exactly once and destroys them again.
1732		2097
1733	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2098	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1734	distribution.	2099	distribution. It uses the L<AE> interface, which makes a real difference
		2100	for the EV and Perl backends only.
1735		2101
1736	=head3 Explanation of the columns	2102	=head3 Explanation of the columns
1737		2103
1738	I<watcher> is the number of event watchers created/destroyed. Since	2104	I<watcher> is the number of event watchers created/destroyed. Since
1739	different event models feature vastly different performances, each event	2105	different event models feature vastly different performances, each event
…		…
1760	watcher.	2126	watcher.
1761		2127
1762	=head3 Results	2128	=head3 Results
1763		2129
1764	name watchers bytes create invoke destroy comment	2130	name watchers bytes create invoke destroy comment
1765	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2131	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1766	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2132	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1767	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2133	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1768	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2134	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1769	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2135	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1770	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2136	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1771	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2137	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1772	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2138	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1773	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2139	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1774	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2140	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1775	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2141	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1776	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2142	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1777		2143
1778	=head3 Discussion	2144	=head3 Discussion
1779		2145
1780	The benchmark does I<not> measure scalability of the event loop very	2146	The benchmark does I<not> measure scalability of the event loop very
1781	well. For example, a select-based event loop (such as the pure perl one)	2147	well. For example, a select-based event loop (such as the pure perl one)
…		…
1793	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2159	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1794	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2160	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1795	cycles with POE.	2161	cycles with POE.
1796		2162
1797	C<EV> is the sole leader regarding speed and memory use, which are both	2163	C<EV> is the sole leader regarding speed and memory use, which are both
1798	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2164	maximal/minimal, respectively. When using the L<AE> API there is zero
		2165	overhead (when going through the AnyEvent API create is about 5-6 times
		2166	slower, with other times being equal, so still uses far less memory than
1799	far less memory than any other event loop and is still faster than Event	2167	any other event loop and is still faster than Event natively).
1800	natively.
1801		2168
1802	The pure perl implementation is hit in a few sweet spots (both the	2169	The pure perl implementation is hit in a few sweet spots (both the
1803	constant timeout and the use of a single fd hit optimisations in the perl	2170	constant timeout and the use of a single fd hit optimisations in the perl
1804	interpreter and the backend itself). Nevertheless this shows that it	2171	interpreter and the backend itself). Nevertheless this shows that it
1805	adds very little overhead in itself. Like any select-based backend its	2172	adds very little overhead in itself. Like any select-based backend its
…		…
1879	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2246	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1880	(1%) are active. This mirrors the activity of large servers with many	2247	(1%) are active. This mirrors the activity of large servers with many
1881	connections, most of which are idle at any one point in time.	2248	connections, most of which are idle at any one point in time.
1882		2249
1883	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2250	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1884	distribution.	2251	distribution. It uses the L<AE> interface, which makes a real difference
		2252	for the EV and Perl backends only.
1885		2253
1886	=head3 Explanation of the columns	2254	=head3 Explanation of the columns
1887		2255
1888	I<sockets> is the number of sockets, and twice the number of "servers" (as	2256	I<sockets> is the number of sockets, and twice the number of "servers" (as
1889	each server has a read and write socket end).	2257	each server has a read and write socket end).
…		…
1897	a new one that moves the timeout into the future.	2265	a new one that moves the timeout into the future.
1898		2266
1899	=head3 Results	2267	=head3 Results
1900		2268
1901	name sockets create request	2269	name sockets create request
1902	EV 20000 69.01 11.16	2270	EV 20000 62.66 7.99
1903	Perl 20000 73.32 35.87	2271	Perl 20000 68.32 32.64
1904	IOAsync 20000 157.00 98.14 epoll	2272	IOAsync 20000 174.06 101.15 epoll
1905	IOAsync 20000 159.31 616.06 poll	2273	IOAsync 20000 174.67 610.84 poll
1906	Event 20000 212.62 257.32	2274	Event 20000 202.69 242.91
1907	Glib 20000 651.16 1896.30	2275	Glib 20000 557.01 1689.52
1908	POE 20000 349.67 12317.24 uses POE::Loop::Event	2276	POE 20000 341.54 12086.32 uses POE::Loop::Event
1909		2277
1910	=head3 Discussion	2278	=head3 Discussion
1911		2279
1912	This benchmark I<does> measure scalability and overall performance of the	2280	This benchmark I<does> measure scalability and overall performance of the
1913	particular event loop.	2281	particular event loop.
…		…
2039	As you can see, the AnyEvent + EV combination even beats the	2407	As you can see, the AnyEvent + EV combination even beats the
2040	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2408	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2041	backend easily beats IO::Lambda and POE.	2409	backend easily beats IO::Lambda and POE.
2042		2410
2043	And even the 100% non-blocking version written using the high-level (and	2411	And even the 100% non-blocking version written using the high-level (and
2044	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2412	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2045	large margin, even though it does all of DNS, tcp-connect and socket I/O	2413	higher level ("unoptimised") abstractions by a large margin, even though
2046	in a non-blocking way.	2414	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2047		2415
2048	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2416	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2049	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2417	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2050	part of the IO::lambda distribution and were used without any changes.	2418	part of the IO::Lambda distribution and were used without any changes.
2051		2419
2052		2420
2053	=head1 SIGNALS	2421	=head1 SIGNALS
2054		2422
2055	AnyEvent currently installs handlers for these signals:	2423	AnyEvent currently installs handlers for these signals:
…		…
2060		2428
2061	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2429	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
2062	emulation for event loops that do not support them natively. Also, some	2430	emulation for event loops that do not support them natively. Also, some
2063	event loops install a similar handler.	2431	event loops install a similar handler.
2064		2432
2065	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will	2433	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2066	reset it to default, to avoid losing child exit statuses.	2434	AnyEvent will reset it to default, to avoid losing child exit statuses.
2067		2435
2068	=item SIGPIPE	2436	=item SIGPIPE
2069		2437
2070	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2438	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
2071	when AnyEvent gets loaded.	2439	when AnyEvent gets loaded.
…		…
2089	if $SIG{CHLD} eq 'IGNORE';	2457	if $SIG{CHLD} eq 'IGNORE';
2090		2458
2091	$SIG{PIPE} = sub { }	2459	$SIG{PIPE} = sub { }
2092	unless defined $SIG{PIPE};	2460	unless defined $SIG{PIPE};
2093		2461
		2462	=head1 RECOMMENDED/OPTIONAL MODULES
		2463
		2464	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2465	it's built-in modules) are required to use it.
		2466
		2467	That does not mean that AnyEvent won't take advantage of some additional
		2468	modules if they are installed.
		2469
		2470	This section explains which additional modules will be used, and how they
		2471	affect AnyEvent's operation.
		2472
		2473	=over 4
		2474
		2475	=item L<Async::Interrupt>
		2476
		2477	This slightly arcane module is used to implement fast signal handling: To
		2478	my knowledge, there is no way to do completely race-free and quick
		2479	signal handling in pure perl. To ensure that signals still get
		2480	delivered, AnyEvent will start an interval timer to wake up perl (and
		2481	catch the signals) with some delay (default is 10 seconds, look for
		2482	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2483
		2484	If this module is available, then it will be used to implement signal
		2485	catching, which means that signals will not be delayed, and the event loop
		2486	will not be interrupted regularly, which is more efficient (and good for
		2487	battery life on laptops).
		2488
		2489	This affects not just the pure-perl event loop, but also other event loops
		2490	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2491
		2492	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2493	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2494	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2495	does nothing for those backends.
		2496
		2497	=item L<EV>
		2498
		2499	This module isn't really "optional", as it is simply one of the backend
		2500	event loops that AnyEvent can use. However, it is simply the best event
		2501	loop available in terms of features, speed and stability: It supports
		2502	the AnyEvent API optimally, implements all the watcher types in XS, does
		2503	automatic timer adjustments even when no monotonic clock is available,
		2504	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2505	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2506	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2507
		2508	=item L<Guard>
		2509
		2510	The guard module, when used, will be used to implement
		2511	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2512	lot less memory), but otherwise doesn't affect guard operation much. It is
		2513	purely used for performance.
		2514
		2515	=item L<JSON> and L<JSON::XS>
		2516
		2517	One of these modules is required when you want to read or write JSON data
		2518	via L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2519	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2520
		2521	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2522	installed.
		2523
		2524	=item L<Net::SSLeay>
		2525
		2526	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2527	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2528	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2529
		2530	=item L<Time::HiRes>
		2531
		2532	This module is part of perl since release 5.008. It will be used when the
		2533	chosen event library does not come with a timing source on it's own. The
		2534	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2535	try to use a monotonic clock for timing stability.
		2536
		2537	=back
		2538
		2539
2094	=head1 FORK	2540	=head1 FORK
2095		2541
2096	Most event libraries are not fork-safe. The ones who are usually are	2542	Most event libraries are not fork-safe. The ones who are usually are
2097	because they rely on inefficient but fork-safe C<select> or C<poll>	2543	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2098	calls. Only L<EV> is fully fork-aware.	2544	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2545	are usually badly thought-out hacks that are incompatible with fork in
		2546	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2547	continue event-processing in both parent and child (or both, if you know
		2548	what you are doing).
		2549
		2550	This means that, in general, you cannot fork and do event processing in
		2551	the child if the event library was initialised before the fork (which
		2552	usually happens when the first AnyEvent watcher is created, or the library
		2553	is loaded).
2099		2554
2100	If you have to fork, you must either do so I<before> creating your first	2555	If you have to fork, you must either do so I<before> creating your first
2101	watcher OR you must not use AnyEvent at all in the child.	2556	watcher OR you must not use AnyEvent at all in the child OR you must do
		2557	something completely out of the scope of AnyEvent.
		2558
		2559	The problem of doing event processing in the parent I<and> the child
		2560	is much more complicated: even for backends that I<are> fork-aware or
		2561	fork-safe, their behaviour is not usually what you want: fork clones all
		2562	watchers, that means all timers, I/O watchers etc. are active in both
		2563	parent and child, which is almost never what you want. USing C<exec>
		2564	to start worker children from some kind of manage rprocess is usually
		2565	preferred, because it is much easier and cleaner, at the expense of having
		2566	to have another binary.
2102		2567
2103		2568
2104	=head1 SECURITY CONSIDERATIONS	2569	=head1 SECURITY CONSIDERATIONS
2105		2570
2106	AnyEvent can be forced to load any event model via	2571	AnyEvent can be forced to load any event model via
…		…
2144	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2609	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2145		2610
2146	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2611	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2147	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2612	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2148	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2613	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2149	L<AnyEvent::Impl::POE>.	2614	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2150		2615
2151	Non-blocking file handles, sockets, TCP clients and	2616	Non-blocking file handles, sockets, TCP clients and
2152	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2617	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2153		2618
2154	Asynchronous DNS: L<AnyEvent::DNS>.	2619	Asynchronous DNS: L<AnyEvent::DNS>.
2155		2620
2156	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2621	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2622	L<Coro::Event>,
2157		2623
2158	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2624	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2625	L<AnyEvent::HTTP>.
2159		2626
2160		2627
2161	=head1 AUTHOR	2628	=head1 AUTHOR
2162		2629
2163	Marc Lehmann <schmorp@schmorp.de>	2630	Marc Lehmann <schmorp@schmorp.de>

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