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Revision 1.196 by root, Thu Mar 26 07:47:42 2009 UTC vs.
Revision 1.317 by root, Wed Mar 24 21:22:57 2010 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
		6	and POE are various supported event loops/environments.
6		7
7	=head1 SYNOPSIS	8	=head1 SYNOPSIS
8		9
9	use AnyEvent;	10	use AnyEvent;
10		11
		12	# file descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { ... });	13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
12		14
		15	# one-shot or repeating timers
13	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
14	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
15		18
16	print AnyEvent->now; # prints current event loop time	19	print AnyEvent->now; # prints current event loop time
17	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
18		21
		22	# POSIX signal
19	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });	23	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
20		24
		25	# child process exit
21	my $w = AnyEvent->child (pid => $pid, cb => sub {	26	my $w = AnyEvent->child (pid => $pid, cb => sub {
22	my ($pid, $status) = @_;	27	my ($pid, $status) = @_;
23	...	28	...
24	});	29	});
		30
		31	# called when event loop idle (if applicable)
		32	my $w = AnyEvent->idle (cb => sub { ... });
25		33
26	my $w = AnyEvent->condvar; # stores whether a condition was flagged	34	my $w = AnyEvent->condvar; # stores whether a condition was flagged
27	$w->send; # wake up current and all future recv's	35	$w->send; # wake up current and all future recv's
28	$w->recv; # enters "main loop" till $condvar gets ->send	36	$w->recv; # enters "main loop" till $condvar gets ->send
29	# use a condvar in callback mode:	37	# use a condvar in callback mode:
…		…
32	=head1 INTRODUCTION/TUTORIAL	40	=head1 INTRODUCTION/TUTORIAL
33		41
34	This manpage is mainly a reference manual. If you are interested	42	This manpage is mainly a reference manual. If you are interested
35	in a tutorial or some gentle introduction, have a look at the	43	in a tutorial or some gentle introduction, have a look at the
36	L<AnyEvent::Intro> manpage.	44	L<AnyEvent::Intro> manpage.
		45
		46	=head1 SUPPORT
		47
		48	There is a mailinglist for discussing all things AnyEvent, and an IRC
		49	channel, too.
		50
		51	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		52	Repository>, at L<http://anyevent.schmorp.de>, for more info.
37		53
38	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	54	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
39		55
40	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	56	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
41	nowadays. So what is different about AnyEvent?	57	nowadays. So what is different about AnyEvent?
…		…
165	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
166	declared.	182	declared.
167		183
168	=head2 I/O WATCHERS	184	=head2 I/O WATCHERS
169		185
		186	$w = AnyEvent->io (
		187	fh => <filehandle_or_fileno>,
		188	poll => <"r" or "w">,
		189	cb => <callback>,
		190	);
		191
170	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
171	with the following mandatory key-value pairs as arguments:	193	with the following mandatory key-value pairs as arguments:
172		194
173	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events	195	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
174	(AnyEvent might or might not keep a reference to this file handle). C<poll>	196	for events (AnyEvent might or might not keep a reference to this file
		197	handle). Note that only file handles pointing to things for which
		198	non-blocking operation makes sense are allowed. This includes sockets,
		199	most character devices, pipes, fifos and so on, but not for example files
		200	or block devices.
		201
175	must be a string that is either C<r> or C<w>, which creates a watcher	202	C<poll> must be a string that is either C<r> or C<w>, which creates a
176	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the	203	watcher waiting for "r"eadable or "w"ritable events, respectively.
		204
177	callback to invoke each time the file handle becomes ready.	205	C<cb> is the callback to invoke each time the file handle becomes ready.
178		206
179	Although the callback might get passed parameters, their value and	207	Although the callback might get passed parameters, their value and
180	presence is undefined and you cannot rely on them. Portable AnyEvent	208	presence is undefined and you cannot rely on them. Portable AnyEvent
181	callbacks cannot use arguments passed to I/O watcher callbacks.	209	callbacks cannot use arguments passed to I/O watcher callbacks.
182		210
…		…
197	undef $w;	225	undef $w;
198	});	226	});
199		227
200	=head2 TIME WATCHERS	228	=head2 TIME WATCHERS
201		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	);
		237
202	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 >>
203	method with the following mandatory arguments:	239	method with the following mandatory arguments:
204		240
205	C<after> specifies after how many seconds (fractional values are	241	C<after> specifies after how many seconds (fractional values are
206	supported) the callback should be invoked. C<cb> is the callback to invoke	242	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
314	In either case, if you care (and in most cases, you don't), then you	350	In either case, if you care (and in most cases, you don't), then you
315	can get whatever behaviour you want with any event loop, by taking the	351	can get whatever behaviour you want with any event loop, by taking the
316	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	352	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
317	account.	353	account.
318		354
		355	=item AnyEvent->now_update
		356
		357	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		358	the current time for each loop iteration (see the discussion of L<<
		359	AnyEvent->now >>, above).
		360
		361	When a callback runs for a long time (or when the process sleeps), then
		362	this "current" time will differ substantially from the real time, which
		363	might affect timers and time-outs.
		364
		365	When this is the case, you can call this method, which will update the
		366	event loop's idea of "current time".
		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
		375	Note that updating the time I<might> cause some events to be handled.
		376
319	=back	377	=back
320		378
321	=head2 SIGNAL WATCHERS	379	=head2 SIGNAL WATCHERS
		380
		381	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
322		382
323	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
324	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
325	callback to be invoked whenever a signal occurs.	385	callback to be invoked whenever a signal occurs.
326		386
…		…
332	invocation, and callback invocation will be synchronous. Synchronous means	392	invocation, and callback invocation will be synchronous. Synchronous means
333	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,
334	but it is guaranteed not to interrupt any other callbacks.	394	but it is guaranteed not to interrupt any other callbacks.
335		395
336	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
337	between multiple watchers.	397	between multiple watchers, and AnyEvent will ensure that signals will not
		398	interrupt your program at bad times.
338		399
339	This watcher might use C<%SIG>, so programs overwriting those signals	400	This watcher might use C<%SIG> (depending on the event loop used),
340	directly will likely not work correctly.	401	so programs overwriting those signals directly will likely not work
		402	correctly.
341		403
342	Example: exit on SIGINT	404	Example: exit on SIGINT
343		405
344	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	406	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
345		407
		408	=head3 Restart Behaviour
		409
		410	While restart behaviour is up to the event loop implementation, most will
		411	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		412	pure perl implementation).
		413
		414	=head3 Safe/Unsafe Signals
		415
		416	Perl signals can be either "safe" (synchronous to opcode handling) or
		417	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		418	latter might corrupt your memory.
		419
		420	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		421	i.e. they will not interrupt your running perl program but will only be
		422	called as part of the normal event handling (just like timer, I/O etc.
		423	callbacks, too).
		424
		425	=head3 Signal Races, Delays and Workarounds
		426
		427	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		428	callbacks to signals in a generic way, which is a pity, as you cannot
		429	do race-free signal handling in perl, requiring C libraries for
		430	this. AnyEvent will try to do it's best, which means in some cases,
		431	signals will be delayed. The maximum time a signal might be delayed is
		432	specified in C<$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
346	=head2 CHILD PROCESS WATCHERS	445	=head2 CHILD PROCESS WATCHERS
347		446
		447	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		448
348	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.
349		450
350	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,
351	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
352	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
353	any trace events (stopped/continued).	454	finished and an exit status is available, not on any trace events
		455	(stopped/continued).
354		456
355	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
356	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
357	callback arguments.	459	callback arguments.
358		460
…		…
363		465
364	There is a slight catch to child watchers, however: you usually start them	466	There is a slight catch to child watchers, however: you usually start them
365	I<after> the child process was created, and this means the process could	467	I<after> the child process was created, and this means the process could
366	have exited already (and no SIGCHLD will be sent anymore).	468	have exited already (and no SIGCHLD will be sent anymore).
367		469
368	Not all event models handle this correctly (POE doesn't), but even for	470	Not all event models handle this correctly (neither POE nor IO::Async do,
		471	see their AnyEvent::Impl manpages for details), but even for event models
369	event models that I<do> handle this correctly, they usually need to be	472	that I<do> handle this correctly, they usually need to be loaded before
370	loaded before the process exits (i.e. before you fork in the first place).	473	the process exits (i.e. before you fork in the first place). AnyEvent's
		474	pure perl event loop handles all cases correctly regardless of when you
		475	start the watcher.
371		476
372	This means you cannot create a child watcher as the very first thing in an	477	This means you cannot create a child watcher as the very first
373	AnyEvent program, you I<have> to create at least one watcher before you	478	thing in an AnyEvent program, you I<have> to create at least one
374	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	479	watcher before you C<fork> the child (alternatively, you can call
		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.
375		485
376	Example: fork a process and wait for it	486	Example: fork a process and wait for it
377		487
378	my $done = AnyEvent->condvar;	488	my $done = AnyEvent->condvar;
379		489
…		…
389	);	499	);
390		500
391	# do something else, then wait for process exit	501	# do something else, then wait for process exit
392	$done->recv;	502	$done->recv;
393		503
		504	=head2 IDLE WATCHERS
		505
		506	$w = AnyEvent->idle (cb => <callback>);
		507
		508	Repeatedly invoke the callback after the process becomes idle, until
		509	either the watcher is destroyed or new events have been detected.
		510
		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
		521	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		522	will simply call the callback "from time to time".
		523
		524	Example: read lines from STDIN, but only process them when the
		525	program is otherwise idle:
		526
		527	my @lines; # read data
		528	my $idle_w;
		529	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		530	push @lines, scalar <STDIN>;
		531
		532	# start an idle watcher, if not already done
		533	$idle_w ||= AnyEvent->idle (cb => sub {
		534	# handle only one line, when there are lines left
		535	if (my $line = shift @lines) {
		536	print "handled when idle: $line";
		537	} else {
		538	# otherwise disable the idle watcher again
		539	undef $idle_w;
		540	}
		541	});
		542	});
		543
394	=head2 CONDITION VARIABLES	544	=head2 CONDITION VARIABLES
		545
		546	$cv = AnyEvent->condvar;
		547
		548	$cv->send (<list>);
		549	my @res = $cv->recv;
395		550
396	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
397	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
398	will actively watch for new events and call your callbacks.	553	will actively watch for new events and call your callbacks.
399		554
400	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
401	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).
402		557
403	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
404	because they represent a condition that must become true.	559	because they represent a condition that must become true.
405		560
		561	Now is probably a good time to look at the examples further below.
		562
406	Condition variables can be created by calling the C<< AnyEvent->condvar	563	Condition variables can be created by calling the C<< AnyEvent->condvar
407	>> method, usually without arguments. The only argument pair allowed is	564	>> method, usually without arguments. The only argument pair allowed is
408
409	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
410	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
411	the results).	567	the results).
412		568
413	After creation, the condition variable is "false" until it becomes "true"	569	After creation, the condition variable is "false" until it becomes "true"
…		…
418	Condition variables are similar to callbacks, except that you can	574	Condition variables are similar to callbacks, except that you can
419	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
420	in time where multiple outstanding events have been processed. And yet	576	in time where multiple outstanding events have been processed. And yet
421	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
422	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
423	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.
424		581
425	Condition variables are very useful to signal that something has finished,	582	Condition variables are very useful to signal that something has finished,
426	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,
427	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
428	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
…		…
462	after => 1,	619	after => 1,
463	cb => sub { $result_ready->send },	620	cb => sub { $result_ready->send },
464	);	621	);
465		622
466	# this "blocks" (while handling events) till the callback	623	# this "blocks" (while handling events) till the callback
467	# calls send	624	# calls ->send
468	$result_ready->recv;	625	$result_ready->recv;
469		626
470	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
471	condition variables are also code references.	628	variables are also callable directly.
472		629
473	my $done = AnyEvent->condvar;	630	my $done = AnyEvent->condvar;
474	my $delay = AnyEvent->timer (after => 5, cb => $done);	631	my $delay = AnyEvent->timer (after => 5, cb => $done);
475	$done->recv;	632	$done->recv;
476		633
…		…
482		639
483	...	640	...
484		641
485	my @info = $couchdb->info->recv;	642	my @info = $couchdb->info->recv;
486		643
487	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
488	results are available:	645	results are available:
489		646
490	$couchdb->info->cb (sub {	647	$couchdb->info->cb (sub {
491	my @info = $_[0]->recv;	648	my @info = $_[0]->recv;
492	});	649	});
…		…
510	immediately from within send.	667	immediately from within send.
511		668
512	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
513	future C<< ->recv >> calls.	670	future C<< ->recv >> calls.
514		671
515	Condition variables are overloaded so one can call them directly	672	Condition variables are overloaded so one can call them directly (as if
516	(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
517	C<send>. Note, however, that many C-based event loops do not handle	674	C<send>.
518	overloading, so as tempting as it may be, passing a condition variable
519	instead of a callback does not work. Both the pure perl and EV loops
520	support overloading, however, as well as all functions that use perl to
521	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
522	example).
523		675
524	=item $cv->croak ($error)	676	=item $cv->croak ($error)
525		677
526	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
527	C<Carp::croak> with the given error message/object/scalar.	679	C<Carp::croak> with the given error message/object/scalar.
528		680
529	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
530	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.
531		687
532	=item $cv->begin ([group callback])	688	=item $cv->begin ([group callback])
533		689
534	=item $cv->end	690	=item $cv->end
535
536	These two methods are EXPERIMENTAL and MIGHT CHANGE.
537		691
538	These two methods can be used to combine many transactions/events into	692	These two methods can be used to combine many transactions/events into
539	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
540	to use a condition variable for the whole process.	694	to use a condition variable for the whole process.
541		695
542	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
543	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
544	>>, 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
545	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
546	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.
547		702
548	Let's clarify this with the ping example:	703	You can think of C<< $cv->send >> giving you an OR condition (one call
		704	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		705	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		706
		707	Let's start with a simple example: you have two I/O watchers (for example,
		708	STDOUT and STDERR for a program), and you want to wait for both streams to
		709	close before activating a condvar:
549		710
550	my $cv = AnyEvent->condvar;	711	my $cv = AnyEvent->condvar;
551		712
		713	$cv->begin; # first watcher
		714	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		715	defined sysread $fh1, my $buf, 4096
		716	or $cv->end;
		717	});
		718
		719	$cv->begin; # second watcher
		720	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		721	defined sysread $fh2, my $buf, 4096
		722	or $cv->end;
		723	});
		724
		725	$cv->recv;
		726
		727	This works because for every event source (EOF on file handle), there is
		728	one call to C<begin>, so the condvar waits for all calls to C<end> before
		729	sending.
		730
		731	The ping example mentioned above is slightly more complicated, as the
		732	there are results to be passwd back, and the number of tasks that are
		733	begung can potentially be zero:
		734
		735	my $cv = AnyEvent->condvar;
		736
552	my %result;	737	my %result;
553	$cv->begin (sub { $cv->send (\%result) });	738	$cv->begin (sub { shift->send (\%result) });
554		739
555	for my $host (@list_of_hosts) {	740	for my $host (@list_of_hosts) {
556	$cv->begin;	741	$cv->begin;
557	ping_host_then_call_callback $host, sub {	742	ping_host_then_call_callback $host, sub {
558	$result{$host} = ...;	743	$result{$host} = ...;
…		…
573	loop, which serves two important purposes: first, it sets the callback	758	loop, which serves two important purposes: first, it sets the callback
574	to be called once the counter reaches C<0>, and second, it ensures that	759	to be called once the counter reaches C<0>, and second, it ensures that
575	C<send> is called even when C<no> hosts are being pinged (the loop	760	C<send> is called even when C<no> hosts are being pinged (the loop
576	doesn't execute once).	761	doesn't execute once).
577		762
578	This is the general pattern when you "fan out" into multiple subrequests:	763	This is the general pattern when you "fan out" into multiple (but
579	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	764	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
580	is called at least once, and then, for each subrequest you start, call	765	the callback and ensure C<end> is called at least once, and then, for each
581	C<begin> and for each subrequest you finish, call C<end>.	766	subrequest you start, call C<begin> and for each subrequest you finish,
		767	call C<end>.
582		768
583	=back	769	=back
584		770
585	=head3 METHODS FOR CONSUMERS	771	=head3 METHODS FOR CONSUMERS
586		772
…		…
602	function will call C<croak>.	788	function will call C<croak>.
603		789
604	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,
605	in scalar context only the first one will be returned.	791	in scalar context only the first one will be returned.
606		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
607	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
608	(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
609	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
610	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
611	condition variables with some kind of request results and supporting	804	condition variables with some kind of request results and supporting
612	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,
613	while still supporting blocking waits if the caller so desires).	806	while still supporting blocking waits if the caller so desires).
614		807
615	Another reason I<never> to C<< ->recv >> in a module is that you cannot
616	sensibly have two C<< ->recv >>'s in parallel, as that would require
617	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
618	can supply.
619
620	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
621	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
622	versions and also integrates coroutines into AnyEvent, making blocking
623	C<< ->recv >> calls perfectly safe as long as they are done from another
624	coroutine (one that doesn't run the event loop).
625
626	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
627	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
628	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
629	waits otherwise.	811	waits otherwise.
630		812
…		…
636	=item $cb = $cv->cb ($cb->($cv))	818	=item $cb = $cv->cb ($cb->($cv))
637		819
638	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
639	replaces it before doing so.	821	replaces it before doing so.
640		822
641	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)
642	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
643	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>
644	is guaranteed not to block.	826	inside the callback or at any later time is guaranteed not to block.
645		827
646	=back	828	=back
647		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
648	=head1 GLOBAL VARIABLES AND FUNCTIONS	898	=head1 GLOBAL VARIABLES AND FUNCTIONS
649		899
		900	These are not normally required to use AnyEvent, but can be useful to
		901	write AnyEvent extension modules.
		902
650	=over 4	903	=over 4
651		904
652	=item $AnyEvent::MODEL	905	=item $AnyEvent::MODEL
653		906
654	Contains C<undef> until the first watcher is being created. Then it	907	Contains C<undef> until the first watcher is being created, before the
		908	backend has been autodetected.
		909
655	contains the event model that is being used, which is the name of the	910	Afterwards it contains the event model that is being used, which is the
656	Perl class implementing the model. This class is usually one of the	911	name of the Perl class implementing the model. This class is usually one
657	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	912	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
658	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	913	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
659		914	will be C<urxvt::anyevent>).
660	The known classes so far are:
661
662	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
663	AnyEvent::Impl::Event based on Event, second best choice.
664	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
665	AnyEvent::Impl::Glib based on Glib, third-best choice.
666	AnyEvent::Impl::Tk based on Tk, very bad choice.
667	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
668	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
669	AnyEvent::Impl::POE based on POE, not generic enough for full support.
670
671	There is no support for WxWidgets, as WxWidgets has no support for
672	watching file handles. However, you can use WxWidgets through the
673	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
674	second, which was considered to be too horrible to even consider for
675	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
676	it's adaptor.
677
678	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
679	autodetecting them.
680		915
681	=item AnyEvent::detect	916	=item AnyEvent::detect
682		917
683	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	918	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
684	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
685	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
686	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>.
687		925
688	=item $guard = AnyEvent::post_detect { BLOCK }	926	=item $guard = AnyEvent::post_detect { BLOCK }
689		927
690	Arranges for the code block to be executed as soon as the event model is	928	Arranges for the code block to be executed as soon as the event model is
691	autodetected (or immediately if this has already happened).	929	autodetected (or immediately if this has already happened).
692		930
		931	The block will be executed I<after> the actual backend has been detected
		932	(C<$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
693	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
694	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
695	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 ||= $guard;
696		962
697	=item @AnyEvent::post_detect	963	=item @AnyEvent::post_detect
698		964
699	If there are any code references in this array (you can C<push> to it	965	If there are any code references in this array (you can C<push> to it
700	before or after loading AnyEvent), then they will called directly after	966	before or after loading AnyEvent), then they will called directly after
701	the event loop has been chosen.	967	the event loop has been chosen.
702		968
703	You should check C<$AnyEvent::MODEL> before adding to this array, though:	969	You should check C<$AnyEvent::MODEL> before adding to this array, though:
704	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
705	and the array will be ignored.	971	array will be ignored.
706		972
707	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	}
708		993
709	=back	994	=back
710		995
711	=head1 WHAT TO DO IN A MODULE	996	=head1 WHAT TO DO IN A MODULE
712		997
…		…
767		1052
768		1053
769	=head1 OTHER MODULES	1054	=head1 OTHER MODULES
770		1055
771	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
772	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
773	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
774	available via CPAN.	1059	come with AnyEvent, most are available via CPAN.
775		1060
776	=over 4	1061	=over 4
777		1062
778	=item L<AnyEvent::Util>	1063	=item L<AnyEvent::Util>
779		1064
…		…
788		1073
789	=item L<AnyEvent::Handle>	1074	=item L<AnyEvent::Handle>
790		1075
791	Provide read and write buffers, manages watchers for reads and writes,	1076	Provide read and write buffers, manages watchers for reads and writes,
792	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
793	non-blocking SSL/TLS.	1078	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
794		1079
795	=item L<AnyEvent::DNS>	1080	=item L<AnyEvent::DNS>
796		1081
797	Provides rich asynchronous DNS resolver capabilities.	1082	Provides rich asynchronous DNS resolver capabilities.
798		1083
…		…
826		1111
827	=item L<AnyEvent::GPSD>	1112	=item L<AnyEvent::GPSD>
828		1113
829	A non-blocking interface to gpsd, a daemon delivering GPS information.	1114	A non-blocking interface to gpsd, a daemon delivering GPS information.
830		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
831	=item L<AnyEvent::IGS>	1125	=item L<AnyEvent::IGS>
832		1126
833	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
834	L<App::IGS>).	1128	L<App::IGS>).
835		1129
836	=item L<AnyEvent::IRC>
837
838	AnyEvent based IRC client module family (replacing the older Net::IRC3).
839
840	=item L<Net::XMPP2>
841
842	AnyEvent based XMPP (Jabber protocol) module family.
843
844	=item L<Net::FCP>	1130	=item L<Net::FCP>
845		1131
846	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1132	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
847	of AnyEvent.	1133	of AnyEvent.
848		1134
…		…
852		1138
853	=item L<Coro>	1139	=item L<Coro>
854		1140
855	Has special support for AnyEvent via L<Coro::AnyEvent>.	1141	Has special support for AnyEvent via L<Coro::AnyEvent>.
856		1142
857	=item L<IO::Lambda>
858
859	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
860
861	=back	1143	=back
862		1144
863	=cut	1145	=cut
864		1146
865	package AnyEvent;	1147	package AnyEvent;
866		1148
867	no warnings;	1149	# basically a tuned-down version of common::sense
868	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	}
869		1156
		1157	BEGIN { AnyEvent::common_sense }
		1158
870	use Carp;	1159	use Carp ();
871		1160
872	our $VERSION = 4.341;	1161	our $VERSION = '5.251';
873	our $MODEL;	1162	our $MODEL;
874		1163
875	our $AUTOLOAD;	1164	our $AUTOLOAD;
876	our @ISA;	1165	our @ISA;
877		1166
878	our @REGISTRY;	1167	our @REGISTRY;
879		1168
880	our $WIN32;	1169	our $VERBOSE;
881		1170
882	BEGIN {	1171	BEGIN {
883	my $win32 = ! ! ($^O =~ /mswin32/i);	1172	require "AnyEvent/constants.pl";
884	eval "sub WIN32(){ $win32 }";
885	}
886		1173
		1174	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
		1175
		1176	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1177	if ${^TAINT};
		1178
887	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1179	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1180
		1181	}
		1182
		1183	our $MAX_SIGNAL_LATENCY = 10;
888		1184
889	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1185	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
890		1186
891	{	1187	{
892	my $idx;	1188	my $idx;
…		…
894	for reverse split /\s*,\s*/,	1190	for reverse split /\s*,\s*/,
895	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1191	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
896	}	1192	}
897		1193
898	my @models = (	1194	my @models = (
899	[EV:: => AnyEvent::Impl::EV::],	1195	[EV:: => AnyEvent::Impl::EV:: , 1],
900	[Event:: => AnyEvent::Impl::Event::],
901	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1196	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
902	# everything below here will not be autoprobed	1197	# everything below here will not (normally) be autoprobed
903	# as the pureperl backend should work everywhere	1198	# as the pureperl backend should work everywhere
904	# 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
905	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1204	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
906	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
907	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
908	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1205	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
909	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1206	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
910	[Wx:: => AnyEvent::Impl::POE::],	1207	[Wx:: => AnyEvent::Impl::POE::],
911	[Prima:: => AnyEvent::Impl::POE::],	1208	[Prima:: => AnyEvent::Impl::POE::],
		1209	# IO::Async is just too broken - we would need workarounds for its
		1210	# byzantine signal and broken child handling, among others.
		1211	# IO::Async is rather hard to detect, as it doesn't have any
		1212	# obvious default class.
		1213	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1214	[IO::Async::Loop:: => 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
912	);	1217	);
913		1218
914	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1219	our %method = map +($_ => 1),
		1220	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
915		1221
916	our @post_detect;	1222	our @post_detect;
917		1223
918	sub post_detect(&) {	1224	sub post_detect(&) {
919	my ($cb) = @_;	1225	my ($cb) = @_;
920		1226
921	if ($MODEL) {
922	$cb->();
923
924	1
925	} else {
926	push @post_detect, $cb;	1227	push @post_detect, $cb;
927		1228
928	defined wantarray	1229	defined wantarray
929	? bless \$cb, "AnyEvent::Util::PostDetect"	1230	? bless \$cb, "AnyEvent::Util::postdetect"
930	: ()	1231	: ()
		1232	}
		1233
		1234	sub AnyEvent::Util::postdetect::DESTROY {
		1235	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1236	}
		1237
		1238	sub detect() {
		1239	# free some memory
		1240	*detect = sub () { $MODEL };
		1241
		1242	local $!; # for good measure
		1243	local $SIG{__DIE__};
		1244
		1245	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1246	my $model = "AnyEvent::Impl::$1";
		1247	if (eval "require $model") {
		1248	$MODEL = $model;
		1249	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1250	} else {
		1251	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1252	}
931	}	1253	}
932	}
933		1254
934	sub AnyEvent::Util::PostDetect::DESTROY {	1255	# check for already loaded models
935	@post_detect = grep $_ != ${$_[0]}, @post_detect;
936	}
937
938	sub detect() {
939	unless ($MODEL) {	1256	unless ($MODEL) {
940	no strict 'refs';	1257	for (@REGISTRY, @models) {
941	local $SIG{__DIE__};	1258	my ($package, $model) = @$_;
942		1259	if (${"$package\::VERSION"} > 0) {
943	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
944	my $model = "AnyEvent::Impl::$1";
945	if (eval "require $model") {	1260	if (eval "require $model") {
946	$MODEL = $model;	1261	$MODEL = $model;
947	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1262	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
948	} else {	1263	last;
949	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1264	}
950	}	1265	}
951	}	1266	}
952		1267
953	# check for already loaded models
954	unless ($MODEL) {	1268	unless ($MODEL) {
		1269	# try to autoload a model
955	for (@REGISTRY, @models) {	1270	for (@REGISTRY, @models) {
956	my ($package, $model) = @$_;	1271	my ($package, $model, $autoload) = @$_;
		1272	if (
		1273	$autoload
		1274	and eval "require $package"
957	if (${"$package\::VERSION"} > 0) {	1275	and ${"$package\::VERSION"} > 0
958	if (eval "require $model") {	1276	and eval "require $model"
		1277	) {
959	$MODEL = $model;	1278	$MODEL = $model;
960	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1279	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
961	last;	1280	last;
962	}
963	}	1281	}
964	}	1282	}
965		1283
966	unless ($MODEL) {
967	# try to load a model
968
969	for (@REGISTRY, @models) {
970	my ($package, $model) = @$_;
971	if (eval "require $package"
972	and ${"$package\::VERSION"} > 0
973	and eval "require $model") {
974	$MODEL = $model;
975	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
976	last;
977	}
978	}
979
980	$MODEL	1284	$MODEL
981	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1285	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
982	}
983	}	1286	}
984
985	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
986
987	unshift @ISA, $MODEL;
988
989	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
990
991	(shift @post_detect)->() while @post_detect;
992	}	1287	}
		1288
		1289	@models = (); # free probe data
		1290
		1291	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1292	unshift @ISA, $MODEL;
		1293
		1294	# now nuke some methods that are overriden by the backend.
		1295	# SUPER is not allowed.
		1296	for (qw(time signal child idle)) {
		1297	undef &{"AnyEvent::Base::$_"}
		1298	if defined &{"$MODEL\::$_"};
		1299	}
		1300
		1301	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1302
		1303	(shift @post_detect)->() while @post_detect;
		1304
		1305	*post_detect = sub(&) {
		1306	shift->();
		1307
		1308	undef
		1309	};
993		1310
994	$MODEL	1311	$MODEL
995	}	1312	}
996		1313
997	sub AUTOLOAD {	1314	sub AUTOLOAD {
998	(my $func = $AUTOLOAD) =~ s/.*://;	1315	(my $func = $AUTOLOAD) =~ s/.*://;
999		1316
1000	$method{$func}	1317	$method{$func}
1001	or croak "$func: not a valid method for AnyEvent objects";	1318	or Carp::croak "$func: not a valid AnyEvent class method";
1002		1319
1003	detect unless $MODEL;	1320	detect;
1004		1321
1005	my $class = shift;	1322	my $class = shift;
1006	$class->$func (@_);	1323	$class->$func (@_);
1007	}	1324	}
1008		1325
1009	# utility function to dup a filehandle. this is used by many backends	1326	# utility function to dup a filehandle. this is used by many backends
1010	# to support binding more than one watcher per filehandle (they usually	1327	# to support binding more than one watcher per filehandle (they usually
1011	# allow only one watcher per fd, so we dup it to get a different one).	1328	# allow only one watcher per fd, so we dup it to get a different one).
1012	sub _dupfh($$$$) {	1329	sub _dupfh($$;$$) {
1013	my ($poll, $fh, $r, $w) = @_;	1330	my ($poll, $fh, $r, $w) = @_;
1014		1331
1015	# cygwin requires the fh mode to be matching, unix doesn't	1332	# cygwin requires the fh mode to be matching, unix doesn't
1016	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1333	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1017	: $poll eq "w" ? ($w, ">")
1018	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1019		1334
1020	open my $fh2, "$mode&" . fileno $fh	1335	open my $fh2, $mode, $fh
1021	or die "cannot dup() filehandle: $!";	1336	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1022		1337
1023	# we assume CLOEXEC is already set by perl in all important cases	1338	# we assume CLOEXEC is already set by perl in all important cases
1024		1339
1025	($fh2, $rw)	1340	($fh2, $rw)
1026	}	1341	}
1027		1342
		1343	=head1 SIMPLIFIED AE API
		1344
		1345	Starting with version 5.0, AnyEvent officially supports a second, much
		1346	simpler, API that is designed to reduce the calling, typing and memory
		1347	overhead.
		1348
		1349	See the L<AE> manpage for details.
		1350
		1351	=cut
		1352
		1353	package AE;
		1354
		1355	our $VERSION = $AnyEvent::VERSION;
		1356
		1357	sub io($$$) {
		1358	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1359	}
		1360
		1361	sub timer($$$) {
		1362	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1363	}
		1364
		1365	sub signal($$) {
		1366	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1367	}
		1368
		1369	sub child($$) {
		1370	AnyEvent->child (pid => $_[0], cb => $_[1])
		1371	}
		1372
		1373	sub idle($) {
		1374	AnyEvent->idle (cb => $_[0])
		1375	}
		1376
		1377	sub cv(;&) {
		1378	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1379	}
		1380
		1381	sub now() {
		1382	AnyEvent->now
		1383	}
		1384
		1385	sub now_update() {
		1386	AnyEvent->now_update
		1387	}
		1388
		1389	sub time() {
		1390	AnyEvent->time
		1391	}
		1392
1028	package AnyEvent::Base;	1393	package AnyEvent::Base;
1029		1394
1030	# default implementation for now and time	1395	# default implementations for many methods
1031		1396
1032	BEGIN {	1397	sub time {
		1398	eval q{ # poor man's autoloading {}
		1399	# probe for availability of Time::HiRes
1033	if (eval "use Time::HiRes (); time (); 1") {	1400	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1401	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1034	*_time = \&Time::HiRes::time;	1402	*AE::time = \&Time::HiRes::time;
1035	# if (eval "use POSIX (); (POSIX::times())...	1403	# if (eval "use POSIX (); (POSIX::times())...
1036	} else {	1404	} else {
		1405	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1037	*_time = sub { time }; # epic fail	1406	*AE::time = sub (){ time }; # epic fail
		1407	}
		1408
		1409	*time = sub { AE::time }; # different prototypes
		1410	};
		1411	die if $@;
		1412
		1413	&time
		1414	}
		1415
		1416	*now = \&time;
		1417
		1418	sub now_update { }
		1419
		1420	# default implementation for ->condvar
		1421
		1422	sub condvar {
		1423	eval q{ # poor man's autoloading {}
		1424	*condvar = sub {
		1425	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1426	};
		1427
		1428	*AE::cv = sub (;&) {
		1429	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1430	};
		1431	};
		1432	die if $@;
		1433
		1434	&condvar
		1435	}
		1436
		1437	# default implementation for ->signal
		1438
		1439	our $HAVE_ASYNC_INTERRUPT;
		1440
		1441	sub _have_async_interrupt() {
		1442	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1443	&& eval "use Async::Interrupt 1.02 (); 1")
		1444	unless defined $HAVE_ASYNC_INTERRUPT;
		1445
		1446	$HAVE_ASYNC_INTERRUPT
		1447	}
		1448
		1449	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1450	our (%SIG_ASY, %SIG_ASY_W);
		1451	our ($SIG_COUNT, $SIG_TW);
		1452
		1453	# install a dummy wakeup watcher to reduce signal catching latency
		1454	# used by Impls
		1455	sub _sig_add() {
		1456	unless ($SIG_COUNT++) {
		1457	# try to align timer on a full-second boundary, if possible
		1458	my $NOW = AE::now;
		1459
		1460	$SIG_TW = AE::timer
		1461	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1462	$MAX_SIGNAL_LATENCY,
		1463	sub { } # just for the PERL_ASYNC_CHECK
		1464	;
1038	}	1465	}
1039	}	1466	}
1040		1467
1041	sub time { _time }	1468	sub _sig_del {
1042	sub now { _time }	1469	undef $SIG_TW
1043		1470	unless --$SIG_COUNT;
1044	# default implementation for ->condvar
1045
1046	sub condvar {
1047	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
1048	}	1471	}
1049		1472
1050	# default implementation for ->signal	1473	our $_sig_name_init; $_sig_name_init = sub {
		1474	eval q{ # poor man's autoloading {}
		1475	undef $_sig_name_init;
1051		1476
1052	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1477	if (_have_async_interrupt) {
		1478	*sig2num = \&Async::Interrupt::sig2num;
		1479	*sig2name = \&Async::Interrupt::sig2name;
		1480	} else {
		1481	require Config;
1053		1482
1054	sub _signal_exec {	1483	my %signame2num;
1055	while (%SIG_EV) {	1484	@signame2num{ split ' ', $Config::Config{sig_name} }
1056	sysread $SIGPIPE_R, my $dummy, 4;	1485	= split ' ', $Config::Config{sig_num};
1057	for (keys %SIG_EV) {	1486
1058	delete $SIG_EV{$_};	1487	my @signum2name;
1059	$_->() for values %{ $SIG_CB{$_} || {} };	1488	@signum2name[values %signame2num] = keys %signame2num;
		1489
		1490	*sig2num = sub($) {
		1491	$_[0] > 0 ? shift : $signame2num{+shift}
		1492	};
		1493	*sig2name = sub ($) {
		1494	$_[0] > 0 ? $signum2name[+shift] : shift
		1495	};
1060	}	1496	}
1061	}	1497	};
1062	}	1498	die if $@;
		1499	};
		1500
		1501	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1502	sub sig2name($) { &$_sig_name_init; &sig2name }
1063		1503
1064	sub signal {	1504	sub signal {
1065	my (undef, %arg) = @_;	1505	eval q{ # poor man's autoloading {}
		1506	# probe for availability of Async::Interrupt
		1507	if (_have_async_interrupt) {
		1508	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1066		1509
1067	unless ($SIGPIPE_R) {	1510	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1068	if (AnyEvent::WIN32) {	1511	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1069	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();	1512
1070	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1071	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1072	} else {	1513	} else {
		1514	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1515
		1516	if (AnyEvent::WIN32) {
		1517	require AnyEvent::Util;
		1518
		1519	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1520	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1521	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1522	} else {
1073	pipe $SIGPIPE_R, $SIGPIPE_W;	1523	pipe $SIGPIPE_R, $SIGPIPE_W;
1074	require Fcntl;
1075	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1524	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1076	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1525	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1526
		1527	# not strictly required, as $^F is normally 2, but let's make sure...
		1528	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1529	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1530	}
		1531
		1532	$SIGPIPE_R
		1533	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1534
		1535	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1077	}	1536	}
1078		1537
1079	$SIGPIPE_R	1538	*signal = $HAVE_ASYNC_INTERRUPT
1080	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1539	? sub {
		1540	my (undef, %arg) = @_;
1081		1541
1082	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1542	# async::interrupt
1083	}
1084
1085	my $signal = uc $arg{signal}	1543	my $signal = sig2num $arg{signal};
1086	or Carp::croak "required option 'signal' is missing";
1087
1088	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1544	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1545
		1546	$SIG_ASY{$signal} ||= new Async::Interrupt
		1547	cb => sub { undef $SIG_EV{$signal} },
		1548	signal => $signal,
		1549	pipe => [$SIGPIPE_R->filenos],
		1550	pipe_autodrain => 0,
		1551	;
		1552
		1553	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1554	}
		1555	: sub {
		1556	my (undef, %arg) = @_;
		1557
		1558	# pure perl
		1559	my $signal = sig2name $arg{signal};
		1560	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1561
1089	$SIG{$signal} ||= sub {	1562	$SIG{$signal} ||= sub {
		1563	local $!;
1090	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1564	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1091	undef $SIG_EV{$signal};	1565	undef $SIG_EV{$signal};
		1566	};
		1567
		1568	# can't do signal processing without introducing races in pure perl,
		1569	# so limit the signal latency.
		1570	_sig_add;
		1571
		1572	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1573	}
		1574	;
		1575
		1576	*AnyEvent::Base::signal::DESTROY = sub {
		1577	my ($signal, $cb) = @{$_[0]};
		1578
		1579	_sig_del;
		1580
		1581	delete $SIG_CB{$signal}{$cb};
		1582
		1583	$HAVE_ASYNC_INTERRUPT
		1584	? delete $SIG_ASY{$signal}
		1585	: # delete doesn't work with older perls - they then
		1586	# print weird messages, or just unconditionally exit
		1587	# instead of getting the default action.
		1588	undef $SIG{$signal}
		1589	unless keys %{ $SIG_CB{$signal} };
		1590	};
		1591
		1592	*_signal_exec = sub {
		1593	$HAVE_ASYNC_INTERRUPT
		1594	? $SIGPIPE_R->drain
		1595	: sysread $SIGPIPE_R, (my $dummy), 9;
		1596
		1597	while (%SIG_EV) {
		1598	for (keys %SIG_EV) {
		1599	delete $SIG_EV{$_};
		1600	$_->() for values %{ $SIG_CB{$_} || {} };
		1601	}
		1602	}
		1603	};
1092	};	1604	};
		1605	die if $@;
1093		1606
1094	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1607	&signal
1095	}
1096
1097	sub AnyEvent::Base::Signal::DESTROY {
1098	my ($signal, $cb) = @{$_[0]};
1099
1100	delete $SIG_CB{$signal}{$cb};
1101
1102	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1103	}	1608	}
1104		1609
1105	# default implementation for ->child	1610	# default implementation for ->child
1106		1611
1107	our %PID_CB;	1612	our %PID_CB;
1108	our $CHLD_W;	1613	our $CHLD_W;
1109	our $CHLD_DELAY_W;	1614	our $CHLD_DELAY_W;
1110	our $PID_IDLE;
1111	our $WNOHANG;	1615	our $WNOHANG;
1112		1616
1113	sub _child_wait {	1617	# used by many Impl's
1114	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1618	sub _emit_childstatus($$) {
		1619	my (undef, $rpid, $rstatus) = @_;
		1620
		1621	$_->($rpid, $rstatus)
1115	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1622	for values %{ $PID_CB{$rpid} || {} },
1116	(values %{ $PID_CB{0} || {} });	1623	values %{ $PID_CB{0} || {} };
1117	}
1118
1119	undef $PID_IDLE;
1120	}
1121
1122	sub _sigchld {
1123	# make sure we deliver these changes "synchronous" with the event loop.
1124	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
1125	undef $CHLD_DELAY_W;
1126	&_child_wait;
1127	});
1128	}	1624	}
1129		1625
1130	sub child {	1626	sub child {
		1627	eval q{ # poor man's autoloading {}
		1628	*_sigchld = sub {
		1629	my $pid;
		1630
		1631	AnyEvent->_emit_childstatus ($pid, $?)
		1632	while ($pid = waitpid -1, $WNOHANG) > 0;
		1633	};
		1634
		1635	*child = sub {
1131	my (undef, %arg) = @_;	1636	my (undef, %arg) = @_;
1132		1637
1133	defined (my $pid = $arg{pid} + 0)	1638	defined (my $pid = $arg{pid} + 0)
1134	or Carp::croak "required option 'pid' is missing";	1639	or Carp::croak "required option 'pid' is missing";
1135		1640
1136	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1641	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1137		1642
1138	unless ($WNOHANG) {	1643	# WNOHANG is almost cetrainly 1 everywhere
		1644	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1645	? 1
1139	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1646	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1140	}
1141		1647
1142	unless ($CHLD_W) {	1648	unless ($CHLD_W) {
1143	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1649	$CHLD_W = AE::signal CHLD => \&_sigchld;
1144	# child could be a zombie already, so make at least one round	1650	# child could be a zombie already, so make at least one round
1145	&_sigchld;	1651	&_sigchld;
1146	}	1652	}
1147		1653
1148	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1654	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1149	}	1655	};
1150		1656
1151	sub AnyEvent::Base::Child::DESTROY {	1657	*AnyEvent::Base::child::DESTROY = sub {
1152	my ($pid, $cb) = @{$_[0]};	1658	my ($pid, $cb) = @{$_[0]};
1153		1659
1154	delete $PID_CB{$pid}{$cb};	1660	delete $PID_CB{$pid}{$cb};
1155	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1661	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1156		1662
1157	undef $CHLD_W unless keys %PID_CB;	1663	undef $CHLD_W unless keys %PID_CB;
		1664	};
		1665	};
		1666	die if $@;
		1667
		1668	&child
		1669	}
		1670
		1671	# idle emulation is done by simply using a timer, regardless
		1672	# of whether the process is idle or not, and not letting
		1673	# the callback use more than 50% of the time.
		1674	sub idle {
		1675	eval q{ # poor man's autoloading {}
		1676	*idle = sub {
		1677	my (undef, %arg) = @_;
		1678
		1679	my ($cb, $w, $rcb) = $arg{cb};
		1680
		1681	$rcb = sub {
		1682	if ($cb) {
		1683	$w = _time;
		1684	&$cb;
		1685	$w = _time - $w;
		1686
		1687	# never use more then 50% of the time for the idle watcher,
		1688	# within some limits
		1689	$w = 0.0001 if $w < 0.0001;
		1690	$w = 5 if $w > 5;
		1691
		1692	$w = AE::timer $w, 0, $rcb;
		1693	} else {
		1694	# clean up...
		1695	undef $w;
		1696	undef $rcb;
		1697	}
		1698	};
		1699
		1700	$w = AE::timer 0.05, 0, $rcb;
		1701
		1702	bless \\$cb, "AnyEvent::Base::idle"
		1703	};
		1704
		1705	*AnyEvent::Base::idle::DESTROY = sub {
		1706	undef $${$_[0]};
		1707	};
		1708	};
		1709	die if $@;
		1710
		1711	&idle
1158	}	1712	}
1159		1713
1160	package AnyEvent::CondVar;	1714	package AnyEvent::CondVar;
1161		1715
1162	our @ISA = AnyEvent::CondVar::Base::;	1716	our @ISA = AnyEvent::CondVar::Base::;
1163		1717
1164	package AnyEvent::CondVar::Base;	1718	package AnyEvent::CondVar::Base;
1165		1719
1166	use overload	1720	#use overload
1167	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1721	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1168	fallback => 1;	1722	# fallback => 1;
		1723
		1724	# save 300+ kilobytes by dirtily hardcoding overloading
		1725	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1726	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1727	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1728	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1729
		1730	our $WAITING;
1169		1731
1170	sub _send {	1732	sub _send {
1171	# nop	1733	# nop
1172	}	1734	}
1173		1735
…		…
1186	sub ready {	1748	sub ready {
1187	$_[0]{_ae_sent}	1749	$_[0]{_ae_sent}
1188	}	1750	}
1189		1751
1190	sub _wait {	1752	sub _wait {
		1753	$WAITING
		1754	and !$_[0]{_ae_sent}
		1755	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1756
		1757	local $WAITING = 1;
1191	AnyEvent->one_event while !$_[0]{_ae_sent};	1758	AnyEvent->one_event while !$_[0]{_ae_sent};
1192	}	1759	}
1193		1760
1194	sub recv {	1761	sub recv {
1195	$_[0]->_wait;	1762	$_[0]->_wait;
…		…
1197	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1764	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1198	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1765	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1199	}	1766	}
1200		1767
1201	sub cb {	1768	sub cb {
1202	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1769	my $cv = shift;
		1770
		1771	@_
		1772	and $cv->{_ae_cb} = shift
		1773	and $cv->{_ae_sent}
		1774	and (delete $cv->{_ae_cb})->($cv);
		1775
1203	$_[0]{_ae_cb}	1776	$cv->{_ae_cb}
1204	}	1777	}
1205		1778
1206	sub begin {	1779	sub begin {
1207	++$_[0]{_ae_counter};	1780	++$_[0]{_ae_counter};
1208	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1781	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1236	so on.	1809	so on.
1237		1810
1238	=head1 ENVIRONMENT VARIABLES	1811	=head1 ENVIRONMENT VARIABLES
1239		1812
1240	The following environment variables are used by this module or its	1813	The following environment variables are used by this module or its
1241	submodules:	1814	submodules.
		1815
		1816	Note that AnyEvent will remove I<all> environment variables starting with
		1817	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1818	enabled.
1242		1819
1243	=over 4	1820	=over 4
1244		1821
1245	=item C<PERL_ANYEVENT_VERBOSE>	1822	=item C<PERL_ANYEVENT_VERBOSE>
1246		1823
…		…
1253	C<PERL_ANYEVENT_MODEL>.	1830	C<PERL_ANYEVENT_MODEL>.
1254		1831
1255	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1832	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1256	model it chooses.	1833	model it chooses.
1257		1834
		1835	When set to C<8> or higher, then AnyEvent will report extra information on
		1836	which optional modules it loads and how it implements certain features.
		1837
1258	=item C<PERL_ANYEVENT_STRICT>	1838	=item C<PERL_ANYEVENT_STRICT>
1259		1839
1260	AnyEvent does not do much argument checking by default, as thorough	1840	AnyEvent does not do much argument checking by default, as thorough
1261	argument checking is very costly. Setting this variable to a true value	1841	argument checking is very costly. Setting this variable to a true value
1262	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1842	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1263	check the arguments passed to most method calls. If it finds any problems	1843	check the arguments passed to most method calls. If it finds any problems,
1264	it will croak.	1844	it will croak.
1265		1845
1266	In other words, enables "strict" mode.	1846	In other words, enables "strict" mode.
1267		1847
1268	Unlike C<use strict>, it is definitely recommended ot keep it off in	1848	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1269	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1849	>>, it is definitely recommended to keep it off in production. Keeping
1270	developing programs can be very useful, however.	1850	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1851	can be very useful, however.
1271		1852
1272	=item C<PERL_ANYEVENT_MODEL>	1853	=item C<PERL_ANYEVENT_MODEL>
1273		1854
1274	This can be used to specify the event model to be used by AnyEvent, before	1855	This can be used to specify the event model to be used by AnyEvent, before
1275	auto detection and -probing kicks in. It must be a string consisting	1856	auto detection and -probing kicks in. It must be a string consisting
…		…
1318		1899
1319	=item C<PERL_ANYEVENT_MAX_FORKS>	1900	=item C<PERL_ANYEVENT_MAX_FORKS>
1320		1901
1321	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1902	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1322	will create in parallel.	1903	will create in parallel.
		1904
		1905	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1906
		1907	The default value for the C<max_outstanding> parameter for the default DNS
		1908	resolver - this is the maximum number of parallel DNS requests that are
		1909	sent to the DNS server.
		1910
		1911	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1912
		1913	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1914	configuration) in the default resolver. When set to the empty string, no
		1915	default config will be used.
		1916
		1917	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1918
		1919	When neither C<ca_file> nor C<ca_path> was specified during
		1920	L<AnyEvent::TLS> context creation, and either of these environment
		1921	variables exist, they will be used to specify CA certificate locations
		1922	instead of a system-dependent default.
		1923
		1924	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1925
		1926	When these are set to C<1>, then the respective modules are not
		1927	loaded. Mostly good for testing AnyEvent itself.
1323		1928
1324	=back	1929	=back
1325		1930
1326	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1931	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1327		1932
…		…
1385	warn "read: $input\n"; # output what has been read	1990	warn "read: $input\n"; # output what has been read
1386	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1991	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1387	},	1992	},
1388	);	1993	);
1389		1994
1390	my $time_watcher; # can only be used once
1391
1392	sub new_timer {
1393	$timer = AnyEvent->timer (after => 1, cb => sub {	1995	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1394	warn "timeout\n"; # print 'timeout' about every second	1996	warn "timeout\n"; # print 'timeout' at most every second
1395	&new_timer; # and restart the time
1396	});	1997	});
1397	}
1398
1399	new_timer; # create first timer
1400		1998
1401	$cv->recv; # wait until user enters /^q/i	1999	$cv->recv; # wait until user enters /^q/i
1402		2000
1403	=head1 REAL-WORLD EXAMPLE	2001	=head1 REAL-WORLD EXAMPLE
1404		2002
…		…
1535	through AnyEvent. The benchmark creates a lot of timers (with a zero	2133	through AnyEvent. The benchmark creates a lot of timers (with a zero
1536	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2134	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1537	which it is), lets them fire exactly once and destroys them again.	2135	which it is), lets them fire exactly once and destroys them again.
1538		2136
1539	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2137	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1540	distribution.	2138	distribution. It uses the L<AE> interface, which makes a real difference
		2139	for the EV and Perl backends only.
1541		2140
1542	=head3 Explanation of the columns	2141	=head3 Explanation of the columns
1543		2142
1544	I<watcher> is the number of event watchers created/destroyed. Since	2143	I<watcher> is the number of event watchers created/destroyed. Since
1545	different event models feature vastly different performances, each event	2144	different event models feature vastly different performances, each event
…		…
1566	watcher.	2165	watcher.
1567		2166
1568	=head3 Results	2167	=head3 Results
1569		2168
1570	name watchers bytes create invoke destroy comment	2169	name watchers bytes create invoke destroy comment
1571	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2170	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1572	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2171	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1573	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2172	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1574	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2173	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1575	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2174	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1576	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2175	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2176	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2177	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1577	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2178	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1578	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2179	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1579	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2180	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1580	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2181	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1581		2182
1582	=head3 Discussion	2183	=head3 Discussion
1583		2184
1584	The benchmark does I<not> measure scalability of the event loop very	2185	The benchmark does I<not> measure scalability of the event loop very
1585	well. For example, a select-based event loop (such as the pure perl one)	2186	well. For example, a select-based event loop (such as the pure perl one)
…		…
1597	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2198	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1598	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2199	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1599	cycles with POE.	2200	cycles with POE.
1600		2201
1601	C<EV> is the sole leader regarding speed and memory use, which are both	2202	C<EV> is the sole leader regarding speed and memory use, which are both
1602	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2203	maximal/minimal, respectively. When using the L<AE> API there is zero
		2204	overhead (when going through the AnyEvent API create is about 5-6 times
		2205	slower, with other times being equal, so still uses far less memory than
1603	far less memory than any other event loop and is still faster than Event	2206	any other event loop and is still faster than Event natively).
1604	natively.
1605		2207
1606	The pure perl implementation is hit in a few sweet spots (both the	2208	The pure perl implementation is hit in a few sweet spots (both the
1607	constant timeout and the use of a single fd hit optimisations in the perl	2209	constant timeout and the use of a single fd hit optimisations in the perl
1608	interpreter and the backend itself). Nevertheless this shows that it	2210	interpreter and the backend itself). Nevertheless this shows that it
1609	adds very little overhead in itself. Like any select-based backend its	2211	adds very little overhead in itself. Like any select-based backend its
1610	performance becomes really bad with lots of file descriptors (and few of	2212	performance becomes really bad with lots of file descriptors (and few of
1611	them active), of course, but this was not subject of this benchmark.	2213	them active), of course, but this was not subject of this benchmark.
1612		2214
1613	The C<Event> module has a relatively high setup and callback invocation	2215	The C<Event> module has a relatively high setup and callback invocation
1614	cost, but overall scores in on the third place.	2216	cost, but overall scores in on the third place.
		2217
		2218	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2219	when using its pure perl backend.
1615		2220
1616	C<Glib>'s memory usage is quite a bit higher, but it features a	2221	C<Glib>'s memory usage is quite a bit higher, but it features a
1617	faster callback invocation and overall ends up in the same class as	2222	faster callback invocation and overall ends up in the same class as
1618	C<Event>. However, Glib scales extremely badly, doubling the number of	2223	C<Event>. However, Glib scales extremely badly, doubling the number of
1619	watchers increases the processing time by more than a factor of four,	2224	watchers increases the processing time by more than a factor of four,
…		…
1680	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2285	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1681	(1%) are active. This mirrors the activity of large servers with many	2286	(1%) are active. This mirrors the activity of large servers with many
1682	connections, most of which are idle at any one point in time.	2287	connections, most of which are idle at any one point in time.
1683		2288
1684	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2289	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1685	distribution.	2290	distribution. It uses the L<AE> interface, which makes a real difference
		2291	for the EV and Perl backends only.
1686		2292
1687	=head3 Explanation of the columns	2293	=head3 Explanation of the columns
1688		2294
1689	I<sockets> is the number of sockets, and twice the number of "servers" (as	2295	I<sockets> is the number of sockets, and twice the number of "servers" (as
1690	each server has a read and write socket end).	2296	each server has a read and write socket end).
…		…
1697	it to another server. This includes deleting the old timeout and creating	2303	it to another server. This includes deleting the old timeout and creating
1698	a new one that moves the timeout into the future.	2304	a new one that moves the timeout into the future.
1699		2305
1700	=head3 Results	2306	=head3 Results
1701		2307
1702	name sockets create request	2308	name sockets create request
1703	EV 20000 69.01 11.16	2309	EV 20000 62.66 7.99
1704	Perl 20000 73.32 35.87	2310	Perl 20000 68.32 32.64
1705	Event 20000 212.62 257.32	2311	IOAsync 20000 174.06 101.15 epoll
1706	Glib 20000 651.16 1896.30	2312	IOAsync 20000 174.67 610.84 poll
		2313	Event 20000 202.69 242.91
		2314	Glib 20000 557.01 1689.52
1707	POE 20000 349.67 12317.24 uses POE::Loop::Event	2315	POE 20000 341.54 12086.32 uses POE::Loop::Event
1708		2316
1709	=head3 Discussion	2317	=head3 Discussion
1710		2318
1711	This benchmark I<does> measure scalability and overall performance of the	2319	This benchmark I<does> measure scalability and overall performance of the
1712	particular event loop.	2320	particular event loop.
…		…
1714	EV is again fastest. Since it is using epoll on my system, the setup time	2322	EV is again fastest. Since it is using epoll on my system, the setup time
1715	is relatively high, though.	2323	is relatively high, though.
1716		2324
1717	Perl surprisingly comes second. It is much faster than the C-based event	2325	Perl surprisingly comes second. It is much faster than the C-based event
1718	loops Event and Glib.	2326	loops Event and Glib.
		2327
		2328	IO::Async performs very well when using its epoll backend, and still quite
		2329	good compared to Glib when using its pure perl backend.
1719		2330
1720	Event suffers from high setup time as well (look at its code and you will	2331	Event suffers from high setup time as well (look at its code and you will
1721	understand why). Callback invocation also has a high overhead compared to	2332	understand why). Callback invocation also has a high overhead compared to
1722	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2333	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1723	uses select or poll in basically all documented configurations.	2334	uses select or poll in basically all documented configurations.
…		…
1786	=item * C-based event loops perform very well with small number of	2397	=item * C-based event loops perform very well with small number of
1787	watchers, as the management overhead dominates.	2398	watchers, as the management overhead dominates.
1788		2399
1789	=back	2400	=back
1790		2401
		2402	=head2 THE IO::Lambda BENCHMARK
		2403
		2404	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2405	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2406	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2407	shouldn't come as a surprise to anybody). As such, the benchmark is
		2408	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2409	very optimal. But how would AnyEvent compare when used without the extra
		2410	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2411
		2412	The benchmark itself creates an echo-server, and then, for 500 times,
		2413	connects to the echo server, sends a line, waits for the reply, and then
		2414	creates the next connection. This is a rather bad benchmark, as it doesn't
		2415	test the efficiency of the framework or much non-blocking I/O, but it is a
		2416	benchmark nevertheless.
		2417
		2418	name runtime
		2419	Lambda/select 0.330 sec
		2420	+ optimized 0.122 sec
		2421	Lambda/AnyEvent 0.327 sec
		2422	+ optimized 0.138 sec
		2423	Raw sockets/select 0.077 sec
		2424	POE/select, components 0.662 sec
		2425	POE/select, raw sockets 0.226 sec
		2426	POE/select, optimized 0.404 sec
		2427
		2428	AnyEvent/select/nb 0.085 sec
		2429	AnyEvent/EV/nb 0.068 sec
		2430	+state machine 0.134 sec
		2431
		2432	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2433	benchmarks actually make blocking connects and use 100% blocking I/O,
		2434	defeating the purpose of an event-based solution. All of the newly
		2435	written AnyEvent benchmarks use 100% non-blocking connects (using
		2436	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2437	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2438	generally require a lot more bookkeeping and event handling than blocking
		2439	connects (which involve a single syscall only).
		2440
		2441	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2442	offers similar expressive power as POE and IO::Lambda, using conventional
		2443	Perl syntax. This means that both the echo server and the client are 100%
		2444	non-blocking, further placing it at a disadvantage.
		2445
		2446	As you can see, the AnyEvent + EV combination even beats the
		2447	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2448	backend easily beats IO::Lambda and POE.
		2449
		2450	And even the 100% non-blocking version written using the high-level (and
		2451	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2452	higher level ("unoptimised") abstractions by a large margin, even though
		2453	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
		2454
		2455	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2456	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2457	part of the IO::Lambda distribution and were used without any changes.
		2458
1791		2459
1792	=head1 SIGNALS	2460	=head1 SIGNALS
1793		2461
1794	AnyEvent currently installs handlers for these signals:	2462	AnyEvent currently installs handlers for these signals:
1795		2463
…		…
1798	=item SIGCHLD	2466	=item SIGCHLD
1799		2467
1800	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2468	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1801	emulation for event loops that do not support them natively. Also, some	2469	emulation for event loops that do not support them natively. Also, some
1802	event loops install a similar handler.	2470	event loops install a similar handler.
		2471
		2472	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2473	AnyEvent will reset it to default, to avoid losing child exit statuses.
1803		2474
1804	=item SIGPIPE	2475	=item SIGPIPE
1805		2476
1806	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2477	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1807	when AnyEvent gets loaded.	2478	when AnyEvent gets loaded.
…		…
1819		2490
1820	=back	2491	=back
1821		2492
1822	=cut	2493	=cut
1823		2494
		2495	undef $SIG{CHLD}
		2496	if $SIG{CHLD} eq 'IGNORE';
		2497
1824	$SIG{PIPE} = sub { }	2498	$SIG{PIPE} = sub { }
1825	unless defined $SIG{PIPE};	2499	unless defined $SIG{PIPE};
1826		2500
		2501	=head1 RECOMMENDED/OPTIONAL MODULES
		2502
		2503	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2504	it's built-in modules) are required to use it.
		2505
		2506	That does not mean that AnyEvent won't take advantage of some additional
		2507	modules if they are installed.
		2508
		2509	This section explains which additional modules will be used, and how they
		2510	affect AnyEvent's operation.
		2511
		2512	=over 4
		2513
		2514	=item L<Async::Interrupt>
		2515
		2516	This slightly arcane module is used to implement fast signal handling: To
		2517	my knowledge, there is no way to do completely race-free and quick
		2518	signal handling in pure perl. To ensure that signals still get
		2519	delivered, AnyEvent will start an interval timer to wake up perl (and
		2520	catch the signals) with some delay (default is 10 seconds, look for
		2521	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2522
		2523	If this module is available, then it will be used to implement signal
		2524	catching, which means that signals will not be delayed, and the event loop
		2525	will not be interrupted regularly, which is more efficient (and good for
		2526	battery life on laptops).
		2527
		2528	This affects not just the pure-perl event loop, but also other event loops
		2529	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2530
		2531	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2532	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2533	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2534	does nothing for those backends.
		2535
		2536	=item L<EV>
		2537
		2538	This module isn't really "optional", as it is simply one of the backend
		2539	event loops that AnyEvent can use. However, it is simply the best event
		2540	loop available in terms of features, speed and stability: It supports
		2541	the AnyEvent API optimally, implements all the watcher types in XS, does
		2542	automatic timer adjustments even when no monotonic clock is available,
		2543	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2544	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2545	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2546
		2547	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2548	then this module will do nothing for you.
		2549
		2550	=item L<Guard>
		2551
		2552	The guard module, when used, will be used to implement
		2553	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2554	lot less memory), but otherwise doesn't affect guard operation much. It is
		2555	purely used for performance.
		2556
		2557	=item L<JSON> and L<JSON::XS>
		2558
		2559	One of these modules is required when you want to read or write JSON data
		2560	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2561	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2562
		2563	=item L<Net::SSLeay>
		2564
		2565	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2566	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2567	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2568
		2569	=item L<Time::HiRes>
		2570
		2571	This module is part of perl since release 5.008. It will be used when the
		2572	chosen event library does not come with a timing source on it's own. The
		2573	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2574	try to use a monotonic clock for timing stability.
		2575
		2576	=back
		2577
1827		2578
1828	=head1 FORK	2579	=head1 FORK
1829		2580
1830	Most event libraries are not fork-safe. The ones who are usually are	2581	Most event libraries are not fork-safe. The ones who are usually are
1831	because they rely on inefficient but fork-safe C<select> or C<poll>	2582	because they rely on inefficient but fork-safe C<select> or C<poll> calls
1832	calls. Only L<EV> is fully fork-aware.	2583	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2584	are usually badly thought-out hacks that are incompatible with fork in
		2585	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2586	continue event-processing in both parent and child (or both, if you know
		2587	what you are doing).
		2588
		2589	This means that, in general, you cannot fork and do event processing in
		2590	the child if the event library was initialised before the fork (which
		2591	usually happens when the first AnyEvent watcher is created, or the library
		2592	is loaded).
1833		2593
1834	If you have to fork, you must either do so I<before> creating your first	2594	If you have to fork, you must either do so I<before> creating your first
1835	watcher OR you must not use AnyEvent at all in the child.	2595	watcher OR you must not use AnyEvent at all in the child OR you must do
		2596	something completely out of the scope of AnyEvent.
		2597
		2598	The problem of doing event processing in the parent I<and> the child
		2599	is much more complicated: even for backends that I<are> fork-aware or
		2600	fork-safe, their behaviour is not usually what you want: fork clones all
		2601	watchers, that means all timers, I/O watchers etc. are active in both
		2602	parent and child, which is almost never what you want. USing C<exec>
		2603	to start worker children from some kind of manage rprocess is usually
		2604	preferred, because it is much easier and cleaner, at the expense of having
		2605	to have another binary.
1836		2606
1837		2607
1838	=head1 SECURITY CONSIDERATIONS	2608	=head1 SECURITY CONSIDERATIONS
1839		2609
1840	AnyEvent can be forced to load any event model via	2610	AnyEvent can be forced to load any event model via
…		…
1852	use AnyEvent;	2622	use AnyEvent;
1853		2623
1854	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2624	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1855	be used to probe what backend is used and gain other information (which is	2625	be used to probe what backend is used and gain other information (which is
1856	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2626	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1857	$ENV{PERL_ANYEGENT_STRICT}.	2627	$ENV{PERL_ANYEVENT_STRICT}.
		2628
		2629	Note that AnyEvent will remove I<all> environment variables starting with
		2630	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2631	enabled.
1858		2632
1859		2633
1860	=head1 BUGS	2634	=head1 BUGS
1861		2635
1862	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2636	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1863	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2637	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1864	and check wether the leaks still show up. (Perl 5.10.0 has other annoying	2638	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1865	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as	2639	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1866	pronounced).	2640	pronounced).
1867		2641
1868		2642
1869	=head1 SEE ALSO	2643	=head1 SEE ALSO
1870		2644
…		…
1874	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2648	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1875		2649
1876	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2650	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1877	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2651	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1878	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2652	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1879	L<AnyEvent::Impl::POE>.	2653	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1880		2654
1881	Non-blocking file handles, sockets, TCP clients and	2655	Non-blocking file handles, sockets, TCP clients and
1882	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2656	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1883		2657
1884	Asynchronous DNS: L<AnyEvent::DNS>.	2658	Asynchronous DNS: L<AnyEvent::DNS>.
1885		2659
1886	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2660	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2661	L<Coro::Event>,
1887		2662
1888	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2663	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2664	L<AnyEvent::HTTP>.
1889		2665
1890		2666
1891	=head1 AUTHOR	2667	=head1 AUTHOR
1892		2668
1893	Marc Lehmann <schmorp@schmorp.de>	2669	Marc Lehmann <schmorp@schmorp.de>

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