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Revision 1.314 by root, Fri Mar 12 23:30:06 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> is the Perl I<file handle> (I<not> file descriptor) to watch	195	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
174	for events (AnyEvent might or might not keep a reference to this file	196	for events (AnyEvent might or might not keep a reference to this file
175	handle). Note that only file handles pointing to things for which	197	handle). Note that only file handles pointing to things for which
176	non-blocking operation makes sense are allowed. This includes sockets,	198	non-blocking operation makes sense are allowed. This includes sockets,
177	most character devices, pipes, fifos and so on, but not for example files	199	most character devices, pipes, fifos and so on, but not for example files
178	or block devices.	200	or block devices.
…		…
203	undef $w;	225	undef $w;
204	});	226	});
205		227
206	=head2 TIME WATCHERS	228	=head2 TIME WATCHERS
207		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
208	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 >>
209	method with the following mandatory arguments:	239	method with the following mandatory arguments:
210		240
211	C<after> specifies after how many seconds (fractional values are	241	C<after> specifies after how many seconds (fractional values are
212	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
…		…
320	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
321	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
322	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	352	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
323	account.	353	account.
324		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
325	=back	377	=back
326		378
327	=head2 SIGNAL WATCHERS	379	=head2 SIGNAL WATCHERS
		380
		381	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
328		382
329	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
330	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
331	callback to be invoked whenever a signal occurs.	385	callback to be invoked whenever a signal occurs.
332		386
…		…
338	invocation, and callback invocation will be synchronous. Synchronous means	392	invocation, and callback invocation will be synchronous. Synchronous means
339	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,
340	but it is guaranteed not to interrupt any other callbacks.	394	but it is guaranteed not to interrupt any other callbacks.
341		395
342	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
343	between multiple watchers.	397	between multiple watchers, and AnyEvent will ensure that signals will not
		398	interrupt your program at bad times.
344		399
345	This watcher might use C<%SIG>, so programs overwriting those signals	400	This watcher might use C<%SIG> (depending on the event loop used),
346	directly will likely not work correctly.	401	so programs overwriting those signals directly will likely not work
		402	correctly.
347		403
348	Example: exit on SIGINT	404	Example: exit on SIGINT
349		405
350	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	406	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
351		407
		408	=head3 Restart Behaviour
		409
		410	While restart behaviour is up to the event loop implementation, most will
		411	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		412	pure perl implementation).
		413
		414	=head3 Safe/Unsafe Signals
		415
		416	Perl signals can be either "safe" (synchronous to opcode handling) or
		417	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		418	latter might corrupt your memory.
		419
		420	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		421	i.e. they will not interrupt your running perl program but will only be
		422	called as part of the normal event handling (just like timer, I/O etc.
		423	callbacks, too).
		424
		425	=head3 Signal Races, Delays and Workarounds
		426
		427	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		428	callbacks to signals in a generic way, which is a pity, as you cannot
		429	do race-free signal handling in perl, requiring C libraries for
		430	this. AnyEvent will try to do it's best, which means in some cases,
		431	signals will be delayed. The maximum time a signal might be delayed is
		432	specified in C<$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
352	=head2 CHILD PROCESS WATCHERS	445	=head2 CHILD PROCESS WATCHERS
353		446
		447	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		448
354	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.
355		450
356	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,
357	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
358	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
359	any trace events (stopped/continued).	454	finished and an exit status is available, not on any trace events
		455	(stopped/continued).
360		456
361	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
362	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
363	callback arguments.	459	callback arguments.
364		460
…		…
369		465
370	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
371	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
372	have exited already (and no SIGCHLD will be sent anymore).	468	have exited already (and no SIGCHLD will be sent anymore).
373		469
374	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
375	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
376	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.
377		476
378	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
379	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
380	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.
381		485
382	Example: fork a process and wait for it	486	Example: fork a process and wait for it
383		487
384	my $done = AnyEvent->condvar;	488	my $done = AnyEvent->condvar;
385		489
…		…
395	);	499	);
396		500
397	# do something else, then wait for process exit	501	# do something else, then wait for process exit
398	$done->recv;	502	$done->recv;
399		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
400	=head2 CONDITION VARIABLES	544	=head2 CONDITION VARIABLES
		545
		546	$cv = AnyEvent->condvar;
		547
		548	$cv->send (<list>);
		549	my @res = $cv->recv;
401		550
402	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
403	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
404	will actively watch for new events and call your callbacks.	553	will actively watch for new events and call your callbacks.
405		554
406	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
407	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).
408		557
409	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
410	because they represent a condition that must become true.	559	because they represent a condition that must become true.
411		560
		561	Now is probably a good time to look at the examples further below.
		562
412	Condition variables can be created by calling the C<< AnyEvent->condvar	563	Condition variables can be created by calling the C<< AnyEvent->condvar
413	>> method, usually without arguments. The only argument pair allowed is	564	>> method, usually without arguments. The only argument pair allowed is
414
415	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
416	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
417	the results).	567	the results).
418		568
419	After creation, the condition variable is "false" until it becomes "true"	569	After creation, the condition variable is "false" until it becomes "true"
…		…
424	Condition variables are similar to callbacks, except that you can	574	Condition variables are similar to callbacks, except that you can
425	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
426	in time where multiple outstanding events have been processed. And yet	576	in time where multiple outstanding events have been processed. And yet
427	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
428	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
429	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.
430		581
431	Condition variables are very useful to signal that something has finished,	582	Condition variables are very useful to signal that something has finished,
432	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,
433	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
434	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
…		…
468	after => 1,	619	after => 1,
469	cb => sub { $result_ready->send },	620	cb => sub { $result_ready->send },
470	);	621	);
471		622
472	# this "blocks" (while handling events) till the callback	623	# this "blocks" (while handling events) till the callback
473	# calls send	624	# calls ->send
474	$result_ready->recv;	625	$result_ready->recv;
475		626
476	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
477	condition variables are also code references.	628	variables are also callable directly.
478		629
479	my $done = AnyEvent->condvar;	630	my $done = AnyEvent->condvar;
480	my $delay = AnyEvent->timer (after => 5, cb => $done);	631	my $delay = AnyEvent->timer (after => 5, cb => $done);
481	$done->recv;	632	$done->recv;
482		633
…		…
488		639
489	...	640	...
490		641
491	my @info = $couchdb->info->recv;	642	my @info = $couchdb->info->recv;
492		643
493	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
494	results are available:	645	results are available:
495		646
496	$couchdb->info->cb (sub {	647	$couchdb->info->cb (sub {
497	my @info = $_[0]->recv;	648	my @info = $_[0]->recv;
498	});	649	});
…		…
516	immediately from within send.	667	immediately from within send.
517		668
518	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
519	future C<< ->recv >> calls.	670	future C<< ->recv >> calls.
520		671
521	Condition variables are overloaded so one can call them directly	672	Condition variables are overloaded so one can call them directly (as if
522	(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
523	C<send>. Note, however, that many C-based event loops do not handle	674	C<send>.
524	overloading, so as tempting as it may be, passing a condition variable
525	instead of a callback does not work. Both the pure perl and EV loops
526	support overloading, however, as well as all functions that use perl to
527	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
528	example).
529		675
530	=item $cv->croak ($error)	676	=item $cv->croak ($error)
531		677
532	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
533	C<Carp::croak> with the given error message/object/scalar.	679	C<Carp::croak> with the given error message/object/scalar.
534		680
535	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
536	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.
537		687
538	=item $cv->begin ([group callback])	688	=item $cv->begin ([group callback])
539		689
540	=item $cv->end	690	=item $cv->end
541
542	These two methods are EXPERIMENTAL and MIGHT CHANGE.
543		691
544	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
545	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
546	to use a condition variable for the whole process.	694	to use a condition variable for the whole process.
547		695
548	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
549	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
550	>>, 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
551	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
552	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.
553		702
554	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:
555		710
556	my $cv = AnyEvent->condvar;	711	my $cv = AnyEvent->condvar;
557		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
558	my %result;	737	my %result;
559	$cv->begin (sub { $cv->send (\%result) });	738	$cv->begin (sub { shift->send (\%result) });
560		739
561	for my $host (@list_of_hosts) {	740	for my $host (@list_of_hosts) {
562	$cv->begin;	741	$cv->begin;
563	ping_host_then_call_callback $host, sub {	742	ping_host_then_call_callback $host, sub {
564	$result{$host} = ...;	743	$result{$host} = ...;
…		…
579	loop, which serves two important purposes: first, it sets the callback	758	loop, which serves two important purposes: first, it sets the callback
580	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
581	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
582	doesn't execute once).	761	doesn't execute once).
583		762
584	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
585	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
586	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
587	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>.
588		768
589	=back	769	=back
590		770
591	=head3 METHODS FOR CONSUMERS	771	=head3 METHODS FOR CONSUMERS
592		772
…		…
608	function will call C<croak>.	788	function will call C<croak>.
609		789
610	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,
611	in scalar context only the first one will be returned.	791	in scalar context only the first one will be returned.
612		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
613	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
614	(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
615	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
616	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
617	condition variables with some kind of request results and supporting	804	condition variables with some kind of request results and supporting
618	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,
619	while still supporting blocking waits if the caller so desires).	806	while still supporting blocking waits if the caller so desires).
620		807
621	Another reason I<never> to C<< ->recv >> in a module is that you cannot
622	sensibly have two C<< ->recv >>'s in parallel, as that would require
623	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
624	can supply.
625
626	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
627	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
628	versions and also integrates coroutines into AnyEvent, making blocking
629	C<< ->recv >> calls perfectly safe as long as they are done from another
630	coroutine (one that doesn't run the event loop).
631
632	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
633	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
634	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
635	waits otherwise.	811	waits otherwise.
636		812
…		…
642	=item $cb = $cv->cb ($cb->($cv))	818	=item $cb = $cv->cb ($cb->($cv))
643		819
644	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
645	replaces it before doing so.	821	replaces it before doing so.
646		822
647	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)
648	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
649	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>
650	is guaranteed not to block.	826	inside the callback or at any later time is guaranteed not to block.
651		827
652	=back	828	=back
653		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
654	=head1 GLOBAL VARIABLES AND FUNCTIONS	898	=head1 GLOBAL VARIABLES AND FUNCTIONS
655		899
		900	These are not normally required to use AnyEvent, but can be useful to
		901	write AnyEvent extension modules.
		902
656	=over 4	903	=over 4
657		904
658	=item $AnyEvent::MODEL	905	=item $AnyEvent::MODEL
659		906
660	Contains C<undef> until the first watcher is being created. Then it	907	Contains C<undef> until the first watcher is being created, before the
		908	backend has been autodetected.
		909
661	contains the event model that is being used, which is the name of the	910	Afterwards it contains the event model that is being used, which is the
662	Perl class implementing the model. This class is usually one of the	911	name of the Perl class implementing the model. This class is usually one
663	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	912	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
664	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	913	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
665		914	will be C<urxvt::anyevent>).
666	The known classes so far are:
667
668	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
669	AnyEvent::Impl::Event based on Event, second best choice.
670	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
671	AnyEvent::Impl::Glib based on Glib, third-best choice.
672	AnyEvent::Impl::Tk based on Tk, very bad choice.
673	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
674	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
675	AnyEvent::Impl::POE based on POE, not generic enough for full support.
676
677	There is no support for WxWidgets, as WxWidgets has no support for
678	watching file handles. However, you can use WxWidgets through the
679	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
680	second, which was considered to be too horrible to even consider for
681	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
682	it's adaptor.
683
684	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
685	autodetecting them.
686		915
687	=item AnyEvent::detect	916	=item AnyEvent::detect
688		917
689	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	918	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
690	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
691	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
692	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>.
693		925
694	=item $guard = AnyEvent::post_detect { BLOCK }	926	=item $guard = AnyEvent::post_detect { BLOCK }
695		927
696	Arranges for the code block to be executed as soon as the event model is	928	Arranges for the code block to be executed as soon as the event model is
697	autodetected (or immediately if this has already happened).	929	autodetected (or immediately if this has already happened).
698		930
		931	The block will be executed I<after> the actual backend has been detected
		932	(C<$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
699	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
700	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
701	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 ||= $guard;
702		962
703	=item @AnyEvent::post_detect	963	=item @AnyEvent::post_detect
704		964
705	If there are any code references in this array (you can C<push> to it	965	If there are any code references in this array (you can C<push> to it
706	before or after loading AnyEvent), then they will called directly after	966	before or after loading AnyEvent), then they will called directly after
707	the event loop has been chosen.	967	the event loop has been chosen.
708		968
709	You should check C<$AnyEvent::MODEL> before adding to this array, though:	969	You should check C<$AnyEvent::MODEL> before adding to this array, though:
710	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
711	and the array will be ignored.	971	array will be ignored.
712		972
713	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	}
714		993
715	=back	994	=back
716		995
717	=head1 WHAT TO DO IN A MODULE	996	=head1 WHAT TO DO IN A MODULE
718		997
…		…
773		1052
774		1053
775	=head1 OTHER MODULES	1054	=head1 OTHER MODULES
776		1055
777	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
778	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
779	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
780	available via CPAN.	1059	come with AnyEvent, most are available via CPAN.
781		1060
782	=over 4	1061	=over 4
783		1062
784	=item L<AnyEvent::Util>	1063	=item L<AnyEvent::Util>
785		1064
…		…
794		1073
795	=item L<AnyEvent::Handle>	1074	=item L<AnyEvent::Handle>
796		1075
797	Provide read and write buffers, manages watchers for reads and writes,	1076	Provide read and write buffers, manages watchers for reads and writes,
798	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
799	non-blocking SSL/TLS.	1078	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
800		1079
801	=item L<AnyEvent::DNS>	1080	=item L<AnyEvent::DNS>
802		1081
803	Provides rich asynchronous DNS resolver capabilities.	1082	Provides rich asynchronous DNS resolver capabilities.
804		1083
…		…
832		1111
833	=item L<AnyEvent::GPSD>	1112	=item L<AnyEvent::GPSD>
834		1113
835	A non-blocking interface to gpsd, a daemon delivering GPS information.	1114	A non-blocking interface to gpsd, a daemon delivering GPS information.
836		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
837	=item L<AnyEvent::IGS>	1125	=item L<AnyEvent::IGS>
838		1126
839	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
840	L<App::IGS>).	1128	L<App::IGS>).
841		1129
842	=item L<AnyEvent::IRC>
843
844	AnyEvent based IRC client module family (replacing the older Net::IRC3).
845
846	=item L<Net::XMPP2>
847
848	AnyEvent based XMPP (Jabber protocol) module family.
849
850	=item L<Net::FCP>	1130	=item L<Net::FCP>
851		1131
852	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1132	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
853	of AnyEvent.	1133	of AnyEvent.
854		1134
…		…
858		1138
859	=item L<Coro>	1139	=item L<Coro>
860		1140
861	Has special support for AnyEvent via L<Coro::AnyEvent>.	1141	Has special support for AnyEvent via L<Coro::AnyEvent>.
862		1142
863	=item L<IO::Lambda>
864
865	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
866
867	=back	1143	=back
868		1144
869	=cut	1145	=cut
870		1146
871	package AnyEvent;	1147	package AnyEvent;
872		1148
873	no warnings;	1149	# basically a tuned-down version of common::sense
874	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	}
875		1156
		1157	BEGIN { AnyEvent::common_sense }
		1158
876	use Carp;	1159	use Carp ();
877		1160
878	our $VERSION = 4.35;	1161	our $VERSION = '5.25';
879	our $MODEL;	1162	our $MODEL;
880		1163
881	our $AUTOLOAD;	1164	our $AUTOLOAD;
882	our @ISA;	1165	our @ISA;
883		1166
884	our @REGISTRY;	1167	our @REGISTRY;
885		1168
886	our $WIN32;	1169	our $VERBOSE;
887		1170
888	BEGIN {	1171	BEGIN {
889	my $win32 = ! ! ($^O =~ /mswin32/i);	1172	require "AnyEvent/constants.pl";
890	eval "sub WIN32(){ $win32 }";
891	}
892		1173
		1174	eval "sub TAINT (){" . (${^TAINT} *1) . "}";
		1175
		1176	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1177	if ${^TAINT};
		1178
893	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1179	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1180
		1181	}
		1182
		1183	our $MAX_SIGNAL_LATENCY = 10;
894		1184
895	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1185	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
896		1186
897	{	1187	{
898	my $idx;	1188	my $idx;
…		…
900	for reverse split /\s*,\s*/,	1190	for reverse split /\s*,\s*/,
901	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1191	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
902	}	1192	}
903		1193
904	my @models = (	1194	my @models = (
905	[EV:: => AnyEvent::Impl::EV::],	1195	[EV:: => AnyEvent::Impl::EV:: , 1],
906	[Event:: => AnyEvent::Impl::Event::],
907	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1196	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
908	# everything below here will not be autoprobed	1197	# everything below here will not (normally) be autoprobed
909	# as the pureperl backend should work everywhere	1198	# as the pureperl backend should work everywhere
910	# 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
911	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1204	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
912	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
913	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
914	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1205	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
915	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1206	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
916	[Wx:: => AnyEvent::Impl::POE::],	1207	[Wx:: => AnyEvent::Impl::POE::],
917	[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
918	);	1217	);
919		1218
920	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1219	our %method = map +($_ => 1),
		1220	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
921		1221
922	our @post_detect;	1222	our @post_detect;
923		1223
924	sub post_detect(&) {	1224	sub post_detect(&) {
925	my ($cb) = @_;	1225	my ($cb) = @_;
926		1226
927	if ($MODEL) {	1227	if ($MODEL) {
928	$cb->();	1228	$cb->();
929		1229
930	1	1230	undef
931	} else {	1231	} else {
932	push @post_detect, $cb;	1232	push @post_detect, $cb;
933		1233
934	defined wantarray	1234	defined wantarray
935	? bless \$cb, "AnyEvent::Util::PostDetect"	1235	? bless \$cb, "AnyEvent::Util::postdetect"
936	: ()	1236	: ()
937	}	1237	}
938	}	1238	}
939		1239
940	sub AnyEvent::Util::PostDetect::DESTROY {	1240	sub AnyEvent::Util::postdetect::DESTROY {
941	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1241	@post_detect = grep $_ != ${$_[0]}, @post_detect;
942	}	1242	}
943		1243
944	sub detect() {	1244	sub detect() {
		1245	# free some memory
		1246	*detect = sub () { $MODEL };
		1247
		1248	local $!; # for good measure
		1249	local $SIG{__DIE__};
		1250
		1251	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1252	my $model = "AnyEvent::Impl::$1";
		1253	if (eval "require $model") {
		1254	$MODEL = $model;
		1255	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1256	} else {
		1257	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1258	}
		1259	}
		1260
		1261	# check for already loaded models
945	unless ($MODEL) {	1262	unless ($MODEL) {
946	no strict 'refs';	1263	for (@REGISTRY, @models) {
947	local $SIG{__DIE__};	1264	my ($package, $model) = @$_;
948		1265	if (${"$package\::VERSION"} > 0) {
949	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
950	my $model = "AnyEvent::Impl::$1";
951	if (eval "require $model") {	1266	if (eval "require $model") {
952	$MODEL = $model;	1267	$MODEL = $model;
953	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1268	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
954	} else {	1269	last;
955	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1270	}
956	}	1271	}
957	}	1272	}
958		1273
959	# check for already loaded models
960	unless ($MODEL) {	1274	unless ($MODEL) {
		1275	# try to autoload a model
961	for (@REGISTRY, @models) {	1276	for (@REGISTRY, @models) {
962	my ($package, $model) = @$_;	1277	my ($package, $model, $autoload) = @$_;
		1278	if (
		1279	$autoload
		1280	and eval "require $package"
963	if (${"$package\::VERSION"} > 0) {	1281	and ${"$package\::VERSION"} > 0
964	if (eval "require $model") {	1282	and eval "require $model"
		1283	) {
965	$MODEL = $model;	1284	$MODEL = $model;
966	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1285	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
967	last;	1286	last;
968	}
969	}	1287	}
970	}	1288	}
971		1289
972	unless ($MODEL) {
973	# try to load a model
974
975	for (@REGISTRY, @models) {
976	my ($package, $model) = @$_;
977	if (eval "require $package"
978	and ${"$package\::VERSION"} > 0
979	and eval "require $model") {
980	$MODEL = $model;
981	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
982	last;
983	}
984	}
985
986	$MODEL	1290	$MODEL
987	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1291	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
988	}
989	}	1292	}
990
991	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
992
993	unshift @ISA, $MODEL;
994
995	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
996
997	(shift @post_detect)->() while @post_detect;
998	}	1293	}
		1294
		1295	@models = (); # free probe data
		1296
		1297	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1298	unshift @ISA, $MODEL;
		1299
		1300	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1301
		1302	(shift @post_detect)->() while @post_detect;
999		1303
1000	$MODEL	1304	$MODEL
1001	}	1305	}
1002		1306
1003	sub AUTOLOAD {	1307	sub AUTOLOAD {
1004	(my $func = $AUTOLOAD) =~ s/.*://;	1308	(my $func = $AUTOLOAD) =~ s/.*://;
1005		1309
1006	$method{$func}	1310	$method{$func}
1007	or croak "$func: not a valid method for AnyEvent objects";	1311	or Carp::croak "$func: not a valid AnyEvent class method";
1008		1312
1009	detect unless $MODEL;	1313	detect;
1010		1314
1011	my $class = shift;	1315	my $class = shift;
1012	$class->$func (@_);	1316	$class->$func (@_);
1013	}	1317	}
1014		1318
1015	# utility function to dup a filehandle. this is used by many backends	1319	# utility function to dup a filehandle. this is used by many backends
1016	# to support binding more than one watcher per filehandle (they usually	1320	# to support binding more than one watcher per filehandle (they usually
1017	# allow only one watcher per fd, so we dup it to get a different one).	1321	# allow only one watcher per fd, so we dup it to get a different one).
1018	sub _dupfh($$$$) {	1322	sub _dupfh($$;$$) {
1019	my ($poll, $fh, $r, $w) = @_;	1323	my ($poll, $fh, $r, $w) = @_;
1020		1324
1021	# cygwin requires the fh mode to be matching, unix doesn't	1325	# cygwin requires the fh mode to be matching, unix doesn't
1022	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1326	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1023	: $poll eq "w" ? ($w, ">")
1024	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1025		1327
1026	open my $fh2, "$mode&" . fileno $fh	1328	open my $fh2, $mode, $fh
1027	or die "cannot dup() filehandle: $!";	1329	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1028		1330
1029	# we assume CLOEXEC is already set by perl in all important cases	1331	# we assume CLOEXEC is already set by perl in all important cases
1030		1332
1031	($fh2, $rw)	1333	($fh2, $rw)
1032	}	1334	}
1033		1335
		1336	=head1 SIMPLIFIED AE API
		1337
		1338	Starting with version 5.0, AnyEvent officially supports a second, much
		1339	simpler, API that is designed to reduce the calling, typing and memory
		1340	overhead.
		1341
		1342	See the L<AE> manpage for details.
		1343
		1344	=cut
		1345
		1346	package AE;
		1347
		1348	our $VERSION = $AnyEvent::VERSION;
		1349
		1350	sub io($$$) {
		1351	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1352	}
		1353
		1354	sub timer($$$) {
		1355	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1356	}
		1357
		1358	sub signal($$) {
		1359	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1360	}
		1361
		1362	sub child($$) {
		1363	AnyEvent->child (pid => $_[0], cb => $_[1])
		1364	}
		1365
		1366	sub idle($) {
		1367	AnyEvent->idle (cb => $_[0])
		1368	}
		1369
		1370	sub cv(;&) {
		1371	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1372	}
		1373
		1374	sub now() {
		1375	AnyEvent->now
		1376	}
		1377
		1378	sub now_update() {
		1379	AnyEvent->now_update
		1380	}
		1381
		1382	sub time() {
		1383	AnyEvent->time
		1384	}
		1385
1034	package AnyEvent::Base;	1386	package AnyEvent::Base;
1035		1387
1036	# default implementation for now and time	1388	# default implementations for many methods
1037		1389
1038	BEGIN {	1390	sub _time() {
		1391	eval q{ # poor man's autoloading
		1392	# probe for availability of Time::HiRes
1039	if (eval "use Time::HiRes (); time (); 1") {	1393	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1394	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1040	*_time = \&Time::HiRes::time;	1395	*_time = \&Time::HiRes::time;
1041	# if (eval "use POSIX (); (POSIX::times())...	1396	# if (eval "use POSIX (); (POSIX::times())...
1042	} else {	1397	} else {
		1398	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1043	*_time = sub { time }; # epic fail	1399	*_time = sub (){ time }; # epic fail
		1400	}
1044	}	1401	};
		1402	die if $@;
		1403
		1404	&_time
1045	}	1405	}
1046		1406
1047	sub time { _time }	1407	sub time { _time }
1048	sub now { _time }	1408	sub now { _time }
		1409	sub now_update { }
1049		1410
1050	# default implementation for ->condvar	1411	# default implementation for ->condvar
1051		1412
1052	sub condvar {	1413	sub condvar {
1053	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1414	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1054	}	1415	}
1055		1416
1056	# default implementation for ->signal	1417	# default implementation for ->signal
1057		1418
		1419	our $HAVE_ASYNC_INTERRUPT;
		1420
		1421	sub _have_async_interrupt() {
		1422	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1423	&& eval "use Async::Interrupt 1.02 (); 1")
		1424	unless defined $HAVE_ASYNC_INTERRUPT;
		1425
		1426	$HAVE_ASYNC_INTERRUPT
		1427	}
		1428
1058	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1429	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1430	our (%SIG_ASY, %SIG_ASY_W);
		1431	our ($SIG_COUNT, $SIG_TW);
1059		1432
1060	sub _signal_exec {	1433	# install a dummy wakeup watcher to reduce signal catching latency
1061	sysread $SIGPIPE_R, my $dummy, 4;	1434	# used by Impls
		1435	sub _sig_add() {
		1436	unless ($SIG_COUNT++) {
		1437	# try to align timer on a full-second boundary, if possible
		1438	my $NOW = AE::now;
1062		1439
1063	while (%SIG_EV) {	1440	$SIG_TW = AE::timer
1064	for (keys %SIG_EV) {	1441	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1065	delete $SIG_EV{$_};	1442	$MAX_SIGNAL_LATENCY,
1066	$_->() for values %{ $SIG_CB{$_} || {} };	1443	sub { } # just for the PERL_ASYNC_CHECK
		1444	;
		1445	}
		1446	}
		1447
		1448	sub _sig_del {
		1449	undef $SIG_TW
		1450	unless --$SIG_COUNT;
		1451	}
		1452
		1453	our $_sig_name_init; $_sig_name_init = sub {
		1454	eval q{ # poor man's autoloading
		1455	undef $_sig_name_init;
		1456
		1457	if (_have_async_interrupt) {
		1458	*sig2num = \&Async::Interrupt::sig2num;
		1459	*sig2name = \&Async::Interrupt::sig2name;
		1460	} else {
		1461	require Config;
		1462
		1463	my %signame2num;
		1464	@signame2num{ split ' ', $Config::Config{sig_name} }
		1465	= split ' ', $Config::Config{sig_num};
		1466
		1467	my @signum2name;
		1468	@signum2name[values %signame2num] = keys %signame2num;
		1469
		1470	*sig2num = sub($) {
		1471	$_[0] > 0 ? shift : $signame2num{+shift}
		1472	};
		1473	*sig2name = sub ($) {
		1474	$_[0] > 0 ? $signum2name[+shift] : shift
		1475	};
1067	}	1476	}
1068	}	1477	};
1069	}	1478	die if $@;
		1479	};
		1480
		1481	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1482	sub sig2name($) { &$_sig_name_init; &sig2name }
1070		1483
1071	sub signal {	1484	sub signal {
1072	my (undef, %arg) = @_;	1485	eval q{ # poor man's autoloading {}
		1486	# probe for availability of Async::Interrupt
		1487	if (_have_async_interrupt) {
		1488	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1073		1489
1074	unless ($SIGPIPE_R) {	1490	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1075	require Fcntl;	1491	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1076		1492
1077	if (AnyEvent::WIN32) {
1078	require AnyEvent::Util;
1079
1080	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1081	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1082	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1083	} else {	1493	} else {
		1494	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1495
		1496	if (AnyEvent::WIN32) {
		1497	require AnyEvent::Util;
		1498
		1499	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1500	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1501	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1502	} else {
1084	pipe $SIGPIPE_R, $SIGPIPE_W;	1503	pipe $SIGPIPE_R, $SIGPIPE_W;
1085	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1504	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1086	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1505	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1506
		1507	# not strictly required, as $^F is normally 2, but let's make sure...
		1508	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1509	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1510	}
		1511
		1512	$SIGPIPE_R
		1513	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1514
		1515	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1087	}	1516	}
1088		1517
1089	$SIGPIPE_R	1518	*signal = sub {
1090	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1519	my (undef, %arg) = @_;
1091		1520
1092	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1093	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1094
1095	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1096	}
1097
1098	my $signal = uc $arg{signal}	1521	my $signal = uc $arg{signal}
1099	or Carp::croak "required option 'signal' is missing";	1522	or Carp::croak "required option 'signal' is missing";
1100		1523
		1524	if ($HAVE_ASYNC_INTERRUPT) {
		1525	# async::interrupt
		1526
		1527	$signal = sig2num $signal;
1101	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1528	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1529
		1530	$SIG_ASY{$signal} ||= new Async::Interrupt
		1531	cb => sub { undef $SIG_EV{$signal} },
		1532	signal => $signal,
		1533	pipe => [$SIGPIPE_R->filenos],
		1534	pipe_autodrain => 0,
		1535	;
		1536
		1537	} else {
		1538	# pure perl
		1539
		1540	# AE::Util has been loaded in signal
		1541	$signal = sig2name $signal;
		1542	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1543
1102	$SIG{$signal} ||= sub {	1544	$SIG{$signal} ||= sub {
		1545	local $!;
1103	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1546	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1104	undef $SIG_EV{$signal};	1547	undef $SIG_EV{$signal};
		1548	};
		1549
		1550	# can't do signal processing without introducing races in pure perl,
		1551	# so limit the signal latency.
		1552	_sig_add;
		1553	}
		1554
		1555	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1556	};
		1557
		1558	*AnyEvent::Base::signal::DESTROY = sub {
		1559	my ($signal, $cb) = @{$_[0]};
		1560
		1561	_sig_del;
		1562
		1563	delete $SIG_CB{$signal}{$cb};
		1564
		1565	$HAVE_ASYNC_INTERRUPT
		1566	? delete $SIG_ASY{$signal}
		1567	: # delete doesn't work with older perls - they then
		1568	# print weird messages, or just unconditionally exit
		1569	# instead of getting the default action.
		1570	undef $SIG{$signal}
		1571	unless keys %{ $SIG_CB{$signal} };
		1572	};
		1573
		1574	*_signal_exec = sub {
		1575	$HAVE_ASYNC_INTERRUPT
		1576	? $SIGPIPE_R->drain
		1577	: sysread $SIGPIPE_R, (my $dummy), 9;
		1578
		1579	while (%SIG_EV) {
		1580	for (keys %SIG_EV) {
		1581	delete $SIG_EV{$_};
		1582	$_->() for values %{ $SIG_CB{$_} || {} };
		1583	}
		1584	}
		1585	};
1105	};	1586	};
		1587	die if $@;
1106		1588
1107	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1589	&signal
1108	}
1109
1110	sub AnyEvent::Base::Signal::DESTROY {
1111	my ($signal, $cb) = @{$_[0]};
1112
1113	delete $SIG_CB{$signal}{$cb};
1114
1115	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1116	}	1590	}
1117		1591
1118	# default implementation for ->child	1592	# default implementation for ->child
1119		1593
1120	our %PID_CB;	1594	our %PID_CB;
1121	our $CHLD_W;	1595	our $CHLD_W;
1122	our $CHLD_DELAY_W;	1596	our $CHLD_DELAY_W;
1123	our $PID_IDLE;
1124	our $WNOHANG;	1597	our $WNOHANG;
1125		1598
1126	sub _child_wait {	1599	# used by many Impl's
1127	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1600	sub _emit_childstatus($$) {
		1601	my (undef, $rpid, $rstatus) = @_;
		1602
		1603	$_->($rpid, $rstatus)
1128	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1604	for values %{ $PID_CB{$rpid} || {} },
1129	(values %{ $PID_CB{0} || {} });	1605	values %{ $PID_CB{0} || {} };
1130	}
1131
1132	undef $PID_IDLE;
1133	}
1134
1135	sub _sigchld {
1136	# make sure we deliver these changes "synchronous" with the event loop.
1137	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
1138	undef $CHLD_DELAY_W;
1139	&_child_wait;
1140	});
1141	}	1606	}
1142		1607
1143	sub child {	1608	sub child {
		1609	eval q{ # poor man's autoloading {}
		1610	*_sigchld = sub {
		1611	my $pid;
		1612
		1613	AnyEvent->_emit_childstatus ($pid, $?)
		1614	while ($pid = waitpid -1, $WNOHANG) > 0;
		1615	};
		1616
		1617	*child = sub {
1144	my (undef, %arg) = @_;	1618	my (undef, %arg) = @_;
1145		1619
1146	defined (my $pid = $arg{pid} + 0)	1620	defined (my $pid = $arg{pid} + 0)
1147	or Carp::croak "required option 'pid' is missing";	1621	or Carp::croak "required option 'pid' is missing";
1148		1622
1149	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1623	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1150		1624
1151	unless ($WNOHANG) {	1625	# WNOHANG is almost cetrainly 1 everywhere
		1626	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1627	? 1
1152	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1628	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1153	}
1154		1629
1155	unless ($CHLD_W) {	1630	unless ($CHLD_W) {
1156	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1631	$CHLD_W = AE::signal CHLD => \&_sigchld;
1157	# child could be a zombie already, so make at least one round	1632	# child could be a zombie already, so make at least one round
1158	&_sigchld;	1633	&_sigchld;
1159	}	1634	}
1160		1635
1161	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1636	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1162	}	1637	};
1163		1638
1164	sub AnyEvent::Base::Child::DESTROY {	1639	*AnyEvent::Base::child::DESTROY = sub {
1165	my ($pid, $cb) = @{$_[0]};	1640	my ($pid, $cb) = @{$_[0]};
1166		1641
1167	delete $PID_CB{$pid}{$cb};	1642	delete $PID_CB{$pid}{$cb};
1168	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1643	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1169		1644
1170	undef $CHLD_W unless keys %PID_CB;	1645	undef $CHLD_W unless keys %PID_CB;
		1646	};
		1647	};
		1648	die if $@;
		1649
		1650	&child
		1651	}
		1652
		1653	# idle emulation is done by simply using a timer, regardless
		1654	# of whether the process is idle or not, and not letting
		1655	# the callback use more than 50% of the time.
		1656	sub idle {
		1657	eval q{ # poor man's autoloading {}
		1658	*idle = sub {
		1659	my (undef, %arg) = @_;
		1660
		1661	my ($cb, $w, $rcb) = $arg{cb};
		1662
		1663	$rcb = sub {
		1664	if ($cb) {
		1665	$w = _time;
		1666	&$cb;
		1667	$w = _time - $w;
		1668
		1669	# never use more then 50% of the time for the idle watcher,
		1670	# within some limits
		1671	$w = 0.0001 if $w < 0.0001;
		1672	$w = 5 if $w > 5;
		1673
		1674	$w = AE::timer $w, 0, $rcb;
		1675	} else {
		1676	# clean up...
		1677	undef $w;
		1678	undef $rcb;
		1679	}
		1680	};
		1681
		1682	$w = AE::timer 0.05, 0, $rcb;
		1683
		1684	bless \\$cb, "AnyEvent::Base::idle"
		1685	};
		1686
		1687	*AnyEvent::Base::idle::DESTROY = sub {
		1688	undef $${$_[0]};
		1689	};
		1690	};
		1691	die if $@;
		1692
		1693	&idle
1171	}	1694	}
1172		1695
1173	package AnyEvent::CondVar;	1696	package AnyEvent::CondVar;
1174		1697
1175	our @ISA = AnyEvent::CondVar::Base::;	1698	our @ISA = AnyEvent::CondVar::Base::;
1176		1699
1177	package AnyEvent::CondVar::Base;	1700	package AnyEvent::CondVar::Base;
1178		1701
1179	use overload	1702	#use overload
1180	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1703	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1181	fallback => 1;	1704	# fallback => 1;
		1705
		1706	# save 300+ kilobytes by dirtily hardcoding overloading
		1707	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1708	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1709	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1710	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1711
		1712	our $WAITING;
1182		1713
1183	sub _send {	1714	sub _send {
1184	# nop	1715	# nop
1185	}	1716	}
1186		1717
…		…
1199	sub ready {	1730	sub ready {
1200	$_[0]{_ae_sent}	1731	$_[0]{_ae_sent}
1201	}	1732	}
1202		1733
1203	sub _wait {	1734	sub _wait {
		1735	$WAITING
		1736	and !$_[0]{_ae_sent}
		1737	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1738
		1739	local $WAITING = 1;
1204	AnyEvent->one_event while !$_[0]{_ae_sent};	1740	AnyEvent->one_event while !$_[0]{_ae_sent};
1205	}	1741	}
1206		1742
1207	sub recv {	1743	sub recv {
1208	$_[0]->_wait;	1744	$_[0]->_wait;
…		…
1210	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1746	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1211	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1747	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1212	}	1748	}
1213		1749
1214	sub cb {	1750	sub cb {
1215	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1751	my $cv = shift;
		1752
		1753	@_
		1754	and $cv->{_ae_cb} = shift
		1755	and $cv->{_ae_sent}
		1756	and (delete $cv->{_ae_cb})->($cv);
		1757
1216	$_[0]{_ae_cb}	1758	$cv->{_ae_cb}
1217	}	1759	}
1218		1760
1219	sub begin {	1761	sub begin {
1220	++$_[0]{_ae_counter};	1762	++$_[0]{_ae_counter};
1221	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1763	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1249	so on.	1791	so on.
1250		1792
1251	=head1 ENVIRONMENT VARIABLES	1793	=head1 ENVIRONMENT VARIABLES
1252		1794
1253	The following environment variables are used by this module or its	1795	The following environment variables are used by this module or its
1254	submodules:	1796	submodules.
		1797
		1798	Note that AnyEvent will remove I<all> environment variables starting with
		1799	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1800	enabled.
1255		1801
1256	=over 4	1802	=over 4
1257		1803
1258	=item C<PERL_ANYEVENT_VERBOSE>	1804	=item C<PERL_ANYEVENT_VERBOSE>
1259		1805
…		…
1266	C<PERL_ANYEVENT_MODEL>.	1812	C<PERL_ANYEVENT_MODEL>.
1267		1813
1268	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1814	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1269	model it chooses.	1815	model it chooses.
1270		1816
		1817	When set to C<8> or higher, then AnyEvent will report extra information on
		1818	which optional modules it loads and how it implements certain features.
		1819
1271	=item C<PERL_ANYEVENT_STRICT>	1820	=item C<PERL_ANYEVENT_STRICT>
1272		1821
1273	AnyEvent does not do much argument checking by default, as thorough	1822	AnyEvent does not do much argument checking by default, as thorough
1274	argument checking is very costly. Setting this variable to a true value	1823	argument checking is very costly. Setting this variable to a true value
1275	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1824	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1276	check the arguments passed to most method calls. If it finds any problems	1825	check the arguments passed to most method calls. If it finds any problems,
1277	it will croak.	1826	it will croak.
1278		1827
1279	In other words, enables "strict" mode.	1828	In other words, enables "strict" mode.
1280		1829
1281	Unlike C<use strict>, it is definitely recommended ot keep it off in	1830	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1282	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1831	>>, it is definitely recommended to keep it off in production. Keeping
1283	developing programs can be very useful, however.	1832	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1833	can be very useful, however.
1284		1834
1285	=item C<PERL_ANYEVENT_MODEL>	1835	=item C<PERL_ANYEVENT_MODEL>
1286		1836
1287	This can be used to specify the event model to be used by AnyEvent, before	1837	This can be used to specify the event model to be used by AnyEvent, before
1288	auto detection and -probing kicks in. It must be a string consisting	1838	auto detection and -probing kicks in. It must be a string consisting
…		…
1331		1881
1332	=item C<PERL_ANYEVENT_MAX_FORKS>	1882	=item C<PERL_ANYEVENT_MAX_FORKS>
1333		1883
1334	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1884	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1335	will create in parallel.	1885	will create in parallel.
		1886
		1887	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1888
		1889	The default value for the C<max_outstanding> parameter for the default DNS
		1890	resolver - this is the maximum number of parallel DNS requests that are
		1891	sent to the DNS server.
		1892
		1893	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1894
		1895	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1896	configuration) in the default resolver. When set to the empty string, no
		1897	default config will be used.
		1898
		1899	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1900
		1901	When neither C<ca_file> nor C<ca_path> was specified during
		1902	L<AnyEvent::TLS> context creation, and either of these environment
		1903	variables exist, they will be used to specify CA certificate locations
		1904	instead of a system-dependent default.
		1905
		1906	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1907
		1908	When these are set to C<1>, then the respective modules are not
		1909	loaded. Mostly good for testing AnyEvent itself.
1336		1910
1337	=back	1911	=back
1338		1912
1339	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1913	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1340		1914
…		…
1398	warn "read: $input\n"; # output what has been read	1972	warn "read: $input\n"; # output what has been read
1399	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1973	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1400	},	1974	},
1401	);	1975	);
1402		1976
1403	my $time_watcher; # can only be used once
1404
1405	sub new_timer {
1406	$timer = AnyEvent->timer (after => 1, cb => sub {	1977	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1407	warn "timeout\n"; # print 'timeout' about every second	1978	warn "timeout\n"; # print 'timeout' at most every second
1408	&new_timer; # and restart the time
1409	});	1979	});
1410	}
1411
1412	new_timer; # create first timer
1413		1980
1414	$cv->recv; # wait until user enters /^q/i	1981	$cv->recv; # wait until user enters /^q/i
1415		1982
1416	=head1 REAL-WORLD EXAMPLE	1983	=head1 REAL-WORLD EXAMPLE
1417		1984
…		…
1548	through AnyEvent. The benchmark creates a lot of timers (with a zero	2115	through AnyEvent. The benchmark creates a lot of timers (with a zero
1549	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2116	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1550	which it is), lets them fire exactly once and destroys them again.	2117	which it is), lets them fire exactly once and destroys them again.
1551		2118
1552	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2119	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1553	distribution.	2120	distribution. It uses the L<AE> interface, which makes a real difference
		2121	for the EV and Perl backends only.
1554		2122
1555	=head3 Explanation of the columns	2123	=head3 Explanation of the columns
1556		2124
1557	I<watcher> is the number of event watchers created/destroyed. Since	2125	I<watcher> is the number of event watchers created/destroyed. Since
1558	different event models feature vastly different performances, each event	2126	different event models feature vastly different performances, each event
…		…
1579	watcher.	2147	watcher.
1580		2148
1581	=head3 Results	2149	=head3 Results
1582		2150
1583	name watchers bytes create invoke destroy comment	2151	name watchers bytes create invoke destroy comment
1584	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2152	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1585	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2153	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1586	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2154	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1587	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2155	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1588	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2156	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1589	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2157	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2158	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2159	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1590	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2160	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1591	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2161	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1592	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2162	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1593	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2163	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1594		2164
1595	=head3 Discussion	2165	=head3 Discussion
1596		2166
1597	The benchmark does I<not> measure scalability of the event loop very	2167	The benchmark does I<not> measure scalability of the event loop very
1598	well. For example, a select-based event loop (such as the pure perl one)	2168	well. For example, a select-based event loop (such as the pure perl one)
…		…
1610	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2180	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1611	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2181	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1612	cycles with POE.	2182	cycles with POE.
1613		2183
1614	C<EV> is the sole leader regarding speed and memory use, which are both	2184	C<EV> is the sole leader regarding speed and memory use, which are both
1615	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2185	maximal/minimal, respectively. When using the L<AE> API there is zero
		2186	overhead (when going through the AnyEvent API create is about 5-6 times
		2187	slower, with other times being equal, so still uses far less memory than
1616	far less memory than any other event loop and is still faster than Event	2188	any other event loop and is still faster than Event natively).
1617	natively.
1618		2189
1619	The pure perl implementation is hit in a few sweet spots (both the	2190	The pure perl implementation is hit in a few sweet spots (both the
1620	constant timeout and the use of a single fd hit optimisations in the perl	2191	constant timeout and the use of a single fd hit optimisations in the perl
1621	interpreter and the backend itself). Nevertheless this shows that it	2192	interpreter and the backend itself). Nevertheless this shows that it
1622	adds very little overhead in itself. Like any select-based backend its	2193	adds very little overhead in itself. Like any select-based backend its
1623	performance becomes really bad with lots of file descriptors (and few of	2194	performance becomes really bad with lots of file descriptors (and few of
1624	them active), of course, but this was not subject of this benchmark.	2195	them active), of course, but this was not subject of this benchmark.
1625		2196
1626	The C<Event> module has a relatively high setup and callback invocation	2197	The C<Event> module has a relatively high setup and callback invocation
1627	cost, but overall scores in on the third place.	2198	cost, but overall scores in on the third place.
		2199
		2200	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2201	when using its pure perl backend.
1628		2202
1629	C<Glib>'s memory usage is quite a bit higher, but it features a	2203	C<Glib>'s memory usage is quite a bit higher, but it features a
1630	faster callback invocation and overall ends up in the same class as	2204	faster callback invocation and overall ends up in the same class as
1631	C<Event>. However, Glib scales extremely badly, doubling the number of	2205	C<Event>. However, Glib scales extremely badly, doubling the number of
1632	watchers increases the processing time by more than a factor of four,	2206	watchers increases the processing time by more than a factor of four,
…		…
1693	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2267	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1694	(1%) are active. This mirrors the activity of large servers with many	2268	(1%) are active. This mirrors the activity of large servers with many
1695	connections, most of which are idle at any one point in time.	2269	connections, most of which are idle at any one point in time.
1696		2270
1697	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2271	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1698	distribution.	2272	distribution. It uses the L<AE> interface, which makes a real difference
		2273	for the EV and Perl backends only.
1699		2274
1700	=head3 Explanation of the columns	2275	=head3 Explanation of the columns
1701		2276
1702	I<sockets> is the number of sockets, and twice the number of "servers" (as	2277	I<sockets> is the number of sockets, and twice the number of "servers" (as
1703	each server has a read and write socket end).	2278	each server has a read and write socket end).
…		…
1710	it to another server. This includes deleting the old timeout and creating	2285	it to another server. This includes deleting the old timeout and creating
1711	a new one that moves the timeout into the future.	2286	a new one that moves the timeout into the future.
1712		2287
1713	=head3 Results	2288	=head3 Results
1714		2289
1715	name sockets create request	2290	name sockets create request
1716	EV 20000 69.01 11.16	2291	EV 20000 62.66 7.99
1717	Perl 20000 73.32 35.87	2292	Perl 20000 68.32 32.64
1718	Event 20000 212.62 257.32	2293	IOAsync 20000 174.06 101.15 epoll
1719	Glib 20000 651.16 1896.30	2294	IOAsync 20000 174.67 610.84 poll
		2295	Event 20000 202.69 242.91
		2296	Glib 20000 557.01 1689.52
1720	POE 20000 349.67 12317.24 uses POE::Loop::Event	2297	POE 20000 341.54 12086.32 uses POE::Loop::Event
1721		2298
1722	=head3 Discussion	2299	=head3 Discussion
1723		2300
1724	This benchmark I<does> measure scalability and overall performance of the	2301	This benchmark I<does> measure scalability and overall performance of the
1725	particular event loop.	2302	particular event loop.
…		…
1727	EV is again fastest. Since it is using epoll on my system, the setup time	2304	EV is again fastest. Since it is using epoll on my system, the setup time
1728	is relatively high, though.	2305	is relatively high, though.
1729		2306
1730	Perl surprisingly comes second. It is much faster than the C-based event	2307	Perl surprisingly comes second. It is much faster than the C-based event
1731	loops Event and Glib.	2308	loops Event and Glib.
		2309
		2310	IO::Async performs very well when using its epoll backend, and still quite
		2311	good compared to Glib when using its pure perl backend.
1732		2312
1733	Event suffers from high setup time as well (look at its code and you will	2313	Event suffers from high setup time as well (look at its code and you will
1734	understand why). Callback invocation also has a high overhead compared to	2314	understand why). Callback invocation also has a high overhead compared to
1735	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2315	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1736	uses select or poll in basically all documented configurations.	2316	uses select or poll in basically all documented configurations.
…		…
1799	=item * C-based event loops perform very well with small number of	2379	=item * C-based event loops perform very well with small number of
1800	watchers, as the management overhead dominates.	2380	watchers, as the management overhead dominates.
1801		2381
1802	=back	2382	=back
1803		2383
		2384	=head2 THE IO::Lambda BENCHMARK
		2385
		2386	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2387	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2388	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2389	shouldn't come as a surprise to anybody). As such, the benchmark is
		2390	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2391	very optimal. But how would AnyEvent compare when used without the extra
		2392	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2393
		2394	The benchmark itself creates an echo-server, and then, for 500 times,
		2395	connects to the echo server, sends a line, waits for the reply, and then
		2396	creates the next connection. This is a rather bad benchmark, as it doesn't
		2397	test the efficiency of the framework or much non-blocking I/O, but it is a
		2398	benchmark nevertheless.
		2399
		2400	name runtime
		2401	Lambda/select 0.330 sec
		2402	+ optimized 0.122 sec
		2403	Lambda/AnyEvent 0.327 sec
		2404	+ optimized 0.138 sec
		2405	Raw sockets/select 0.077 sec
		2406	POE/select, components 0.662 sec
		2407	POE/select, raw sockets 0.226 sec
		2408	POE/select, optimized 0.404 sec
		2409
		2410	AnyEvent/select/nb 0.085 sec
		2411	AnyEvent/EV/nb 0.068 sec
		2412	+state machine 0.134 sec
		2413
		2414	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2415	benchmarks actually make blocking connects and use 100% blocking I/O,
		2416	defeating the purpose of an event-based solution. All of the newly
		2417	written AnyEvent benchmarks use 100% non-blocking connects (using
		2418	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2419	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2420	generally require a lot more bookkeeping and event handling than blocking
		2421	connects (which involve a single syscall only).
		2422
		2423	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2424	offers similar expressive power as POE and IO::Lambda, using conventional
		2425	Perl syntax. This means that both the echo server and the client are 100%
		2426	non-blocking, further placing it at a disadvantage.
		2427
		2428	As you can see, the AnyEvent + EV combination even beats the
		2429	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2430	backend easily beats IO::Lambda and POE.
		2431
		2432	And even the 100% non-blocking version written using the high-level (and
		2433	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2434	higher level ("unoptimised") abstractions by a large margin, even though
		2435	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
		2436
		2437	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2438	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2439	part of the IO::Lambda distribution and were used without any changes.
		2440
1804		2441
1805	=head1 SIGNALS	2442	=head1 SIGNALS
1806		2443
1807	AnyEvent currently installs handlers for these signals:	2444	AnyEvent currently installs handlers for these signals:
1808		2445
…		…
1811	=item SIGCHLD	2448	=item SIGCHLD
1812		2449
1813	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2450	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1814	emulation for event loops that do not support them natively. Also, some	2451	emulation for event loops that do not support them natively. Also, some
1815	event loops install a similar handler.	2452	event loops install a similar handler.
		2453
		2454	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2455	AnyEvent will reset it to default, to avoid losing child exit statuses.
1816		2456
1817	=item SIGPIPE	2457	=item SIGPIPE
1818		2458
1819	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2459	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1820	when AnyEvent gets loaded.	2460	when AnyEvent gets loaded.
…		…
1832		2472
1833	=back	2473	=back
1834		2474
1835	=cut	2475	=cut
1836		2476
		2477	undef $SIG{CHLD}
		2478	if $SIG{CHLD} eq 'IGNORE';
		2479
1837	$SIG{PIPE} = sub { }	2480	$SIG{PIPE} = sub { }
1838	unless defined $SIG{PIPE};	2481	unless defined $SIG{PIPE};
1839		2482
		2483	=head1 RECOMMENDED/OPTIONAL MODULES
		2484
		2485	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2486	it's built-in modules) are required to use it.
		2487
		2488	That does not mean that AnyEvent won't take advantage of some additional
		2489	modules if they are installed.
		2490
		2491	This section explains which additional modules will be used, and how they
		2492	affect AnyEvent's operation.
		2493
		2494	=over 4
		2495
		2496	=item L<Async::Interrupt>
		2497
		2498	This slightly arcane module is used to implement fast signal handling: To
		2499	my knowledge, there is no way to do completely race-free and quick
		2500	signal handling in pure perl. To ensure that signals still get
		2501	delivered, AnyEvent will start an interval timer to wake up perl (and
		2502	catch the signals) with some delay (default is 10 seconds, look for
		2503	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2504
		2505	If this module is available, then it will be used to implement signal
		2506	catching, which means that signals will not be delayed, and the event loop
		2507	will not be interrupted regularly, which is more efficient (and good for
		2508	battery life on laptops).
		2509
		2510	This affects not just the pure-perl event loop, but also other event loops
		2511	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2512
		2513	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2514	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2515	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2516	does nothing for those backends.
		2517
		2518	=item L<EV>
		2519
		2520	This module isn't really "optional", as it is simply one of the backend
		2521	event loops that AnyEvent can use. However, it is simply the best event
		2522	loop available in terms of features, speed and stability: It supports
		2523	the AnyEvent API optimally, implements all the watcher types in XS, does
		2524	automatic timer adjustments even when no monotonic clock is available,
		2525	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2526	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2527	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2528
		2529	=item L<Guard>
		2530
		2531	The guard module, when used, will be used to implement
		2532	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2533	lot less memory), but otherwise doesn't affect guard operation much. It is
		2534	purely used for performance.
		2535
		2536	=item L<JSON> and L<JSON::XS>
		2537
		2538	One of these modules is required when you want to read or write JSON data
		2539	via L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2540	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2541
		2542	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2543	installed.
		2544
		2545	=item L<Net::SSLeay>
		2546
		2547	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2548	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2549	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2550
		2551	=item L<Time::HiRes>
		2552
		2553	This module is part of perl since release 5.008. It will be used when the
		2554	chosen event library does not come with a timing source on it's own. The
		2555	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2556	try to use a monotonic clock for timing stability.
		2557
		2558	=back
		2559
1840		2560
1841	=head1 FORK	2561	=head1 FORK
1842		2562
1843	Most event libraries are not fork-safe. The ones who are usually are	2563	Most event libraries are not fork-safe. The ones who are usually are
1844	because they rely on inefficient but fork-safe C<select> or C<poll>	2564	because they rely on inefficient but fork-safe C<select> or C<poll> calls
1845	calls. Only L<EV> is fully fork-aware.	2565	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2566	are usually badly thought-out hacks that are incompatible with fork in
		2567	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2568	continue event-processing in both parent and child (or both, if you know
		2569	what you are doing).
		2570
		2571	This means that, in general, you cannot fork and do event processing in
		2572	the child if the event library was initialised before the fork (which
		2573	usually happens when the first AnyEvent watcher is created, or the library
		2574	is loaded).
1846		2575
1847	If you have to fork, you must either do so I<before> creating your first	2576	If you have to fork, you must either do so I<before> creating your first
1848	watcher OR you must not use AnyEvent at all in the child.	2577	watcher OR you must not use AnyEvent at all in the child OR you must do
		2578	something completely out of the scope of AnyEvent.
		2579
		2580	The problem of doing event processing in the parent I<and> the child
		2581	is much more complicated: even for backends that I<are> fork-aware or
		2582	fork-safe, their behaviour is not usually what you want: fork clones all
		2583	watchers, that means all timers, I/O watchers etc. are active in both
		2584	parent and child, which is almost never what you want. USing C<exec>
		2585	to start worker children from some kind of manage rprocess is usually
		2586	preferred, because it is much easier and cleaner, at the expense of having
		2587	to have another binary.
1849		2588
1850		2589
1851	=head1 SECURITY CONSIDERATIONS	2590	=head1 SECURITY CONSIDERATIONS
1852		2591
1853	AnyEvent can be forced to load any event model via	2592	AnyEvent can be forced to load any event model via
…		…
1865	use AnyEvent;	2604	use AnyEvent;
1866		2605
1867	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2606	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1868	be used to probe what backend is used and gain other information (which is	2607	be used to probe what backend is used and gain other information (which is
1869	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2608	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1870	$ENV{PERL_ANYEGENT_STRICT}.	2609	$ENV{PERL_ANYEVENT_STRICT}.
		2610
		2611	Note that AnyEvent will remove I<all> environment variables starting with
		2612	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2613	enabled.
1871		2614
1872		2615
1873	=head1 BUGS	2616	=head1 BUGS
1874		2617
1875	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2618	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
…		…
1887	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2630	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1888		2631
1889	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2632	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1890	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2633	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1891	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2634	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1892	L<AnyEvent::Impl::POE>.	2635	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1893		2636
1894	Non-blocking file handles, sockets, TCP clients and	2637	Non-blocking file handles, sockets, TCP clients and
1895	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2638	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1896		2639
1897	Asynchronous DNS: L<AnyEvent::DNS>.	2640	Asynchronous DNS: L<AnyEvent::DNS>.
1898		2641
1899	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2642	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2643	L<Coro::Event>,
1900		2644
1901	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2645	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2646	L<AnyEvent::HTTP>.
1902		2647
1903		2648
1904	=head1 AUTHOR	2649	=head1 AUTHOR
1905		2650
1906	Marc Lehmann <schmorp@schmorp.de>	2651	Marc Lehmann <schmorp@schmorp.de>

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