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Revision 1.312 by root, Mon Feb 15 18:02:35 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 $condvar gets ->send
29	# use a condvar in callback mode:	37	# use a condvar in callback mode:
…		…
32	=head1 INTRODUCTION/TUTORIAL	40	=head1 INTRODUCTION/TUTORIAL
33		41
34	This manpage is mainly a reference manual. If you are interested	42	This manpage is mainly a reference manual. If you are interested
35	in a tutorial or some gentle introduction, have a look at the	43	in a tutorial or some gentle introduction, have a look at the
36	L<AnyEvent::Intro> manpage.	44	L<AnyEvent::Intro> manpage.
		45
		46	=head1 SUPPORT
		47
		48	There is a mailinglist for discussing all things AnyEvent, and an IRC
		49	channel, too.
		50
		51	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		52	Repository>, at L<http://anyevent.schmorp.de>, for more info.
37		53
38	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	54	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
39		55
40	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	56	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
41	nowadays. So what is different about AnyEvent?	57	nowadays. So what is different about AnyEvent?
…		…
137	These watchers are normal Perl objects with normal Perl lifetime. After	153	These watchers are normal Perl objects with normal Perl lifetime. After
138	creating a watcher it will immediately "watch" for events and invoke the	154	creating a watcher it will immediately "watch" for events and invoke the
139	callback when the event occurs (of course, only when the event model	155	callback when the event occurs (of course, only when the event model
140	is in control).	156	is in control).
141		157
		158	Note that B<callbacks must not permanently change global variables>
		159	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
		160	callbacks must not C<die> >>. The former is good programming practise in
		161	Perl and the latter stems from the fact that exception handling differs
		162	widely between event loops.
		163
142	To disable the watcher you have to destroy it (e.g. by setting the	164	To disable the watcher you have to destroy it (e.g. by setting the
143	variable you store it in to C<undef> or otherwise deleting all references	165	variable you store it in to C<undef> or otherwise deleting all references
144	to it).	166	to it).
145		167
146	All watchers are created by calling a method on the C<AnyEvent> class.	168	All watchers are created by calling a method on the C<AnyEvent> class.
…		…
159	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
160	declared.	182	declared.
161		183
162	=head2 I/O WATCHERS	184	=head2 I/O WATCHERS
163		185
		186	$w = AnyEvent->io (
		187	fh => <filehandle_or_fileno>,
		188	poll => <"r" or "w">,
		189	cb => <callback>,
		190	);
		191
164	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
165	with the following mandatory key-value pairs as arguments:	193	with the following mandatory key-value pairs as arguments:
166		194
167	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events	195	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
168	(AnyEvent might or might not keep a reference to this file handle). C<poll>	196	for events (AnyEvent might or might not keep a reference to this file
		197	handle). Note that only file handles pointing to things for which
		198	non-blocking operation makes sense are allowed. This includes sockets,
		199	most character devices, pipes, fifos and so on, but not for example files
		200	or block devices.
		201
169	must be a string that is either C<r> or C<w>, which creates a watcher	202	C<poll> must be a string that is either C<r> or C<w>, which creates a
170	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the	203	watcher waiting for "r"eadable or "w"ritable events, respectively.
		204
171	callback to invoke each time the file handle becomes ready.	205	C<cb> is the callback to invoke each time the file handle becomes ready.
172		206
173	Although the callback might get passed parameters, their value and	207	Although the callback might get passed parameters, their value and
174	presence is undefined and you cannot rely on them. Portable AnyEvent	208	presence is undefined and you cannot rely on them. Portable AnyEvent
175	callbacks cannot use arguments passed to I/O watcher callbacks.	209	callbacks cannot use arguments passed to I/O watcher callbacks.
176		210
…		…
191	undef $w;	225	undef $w;
192	});	226	});
193		227
194	=head2 TIME WATCHERS	228	=head2 TIME WATCHERS
195		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
196	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 >>
197	method with the following mandatory arguments:	239	method with the following mandatory arguments:
198		240
199	C<after> specifies after how many seconds (fractional values are	241	C<after> specifies after how many seconds (fractional values are
200	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
…		…
308	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
309	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
310	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	352	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
311	account.	353	account.
312		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
313	=back	377	=back
314		378
315	=head2 SIGNAL WATCHERS	379	=head2 SIGNAL WATCHERS
		380
		381	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
316		382
317	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
318	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
319	callback to be invoked whenever a signal occurs.	385	callback to be invoked whenever a signal occurs.
320		386
…		…
326	invocation, and callback invocation will be synchronous. Synchronous means	392	invocation, and callback invocation will be synchronous. Synchronous means
327	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,
328	but it is guaranteed not to interrupt any other callbacks.	394	but it is guaranteed not to interrupt any other callbacks.
329		395
330	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
331	between multiple watchers.	397	between multiple watchers, and AnyEvent will ensure that signals will not
		398	interrupt your program at bad times.
332		399
333	This watcher might use C<%SIG>, so programs overwriting those signals	400	This watcher might use C<%SIG> (depending on the event loop used),
334	directly will likely not work correctly.	401	so programs overwriting those signals directly will likely not work
		402	correctly.
335		403
336	Example: exit on SIGINT	404	Example: exit on SIGINT
337		405
338	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	406	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
339		407
		408	=head3 Restart Behaviour
		409
		410	While restart behaviour is up to the event loop implementation, most will
		411	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		412	pure perl implementation).
		413
		414	=head3 Safe/Unsafe Signals
		415
		416	Perl signals can be either "safe" (synchronous to opcode handling) or
		417	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		418	latter might corrupt your memory.
		419
		420	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		421	i.e. they will not interrupt your running perl program but will only be
		422	called as part of the normal event handling (just like timer, I/O etc.
		423	callbacks, too).
		424
		425	=head3 Signal Races, Delays and Workarounds
		426
		427	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		428	callbacks to signals in a generic way, which is a pity, as you cannot
		429	do race-free signal handling in perl, requiring C libraries for
		430	this. AnyEvent will try to do it's best, which means in some cases,
		431	signals will be delayed. The maximum time a signal might be delayed is
		432	specified in C<$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
340	=head2 CHILD PROCESS WATCHERS	445	=head2 CHILD PROCESS WATCHERS
341		446
		447	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		448
342	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.
343		450
344	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,
345	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
346	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
347	any trace events (stopped/continued).	454	finished and an exit status is available, not on any trace events
		455	(stopped/continued).
348		456
349	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
350	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
351	callback arguments.	459	callback arguments.
352		460
…		…
357		465
358	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
359	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
360	have exited already (and no SIGCHLD will be sent anymore).	468	have exited already (and no SIGCHLD will be sent anymore).
361		469
362	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
363	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
364	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.
365		476
366	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
367	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
368	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.
369		485
370	Example: fork a process and wait for it	486	Example: fork a process and wait for it
371		487
372	my $done = AnyEvent->condvar;	488	my $done = AnyEvent->condvar;
373		489
…		…
383	);	499	);
384		500
385	# do something else, then wait for process exit	501	# do something else, then wait for process exit
386	$done->recv;	502	$done->recv;
387		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
388	=head2 CONDITION VARIABLES	544	=head2 CONDITION VARIABLES
		545
		546	$cv = AnyEvent->condvar;
		547
		548	$cv->send (<list>);
		549	my @res = $cv->recv;
389		550
390	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
391	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
392	will actively watch for new events and call your callbacks.	553	will actively watch for new events and call your callbacks.
393		554
394	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
395	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).
396		557
397	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
398	because they represent a condition that must become true.	559	because they represent a condition that must become true.
399		560
		561	Now is probably a good time to look at the examples further below.
		562
400	Condition variables can be created by calling the C<< AnyEvent->condvar	563	Condition variables can be created by calling the C<< AnyEvent->condvar
401	>> method, usually without arguments. The only argument pair allowed is	564	>> method, usually without arguments. The only argument pair allowed is
402
403	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
404	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
405	the results).	567	the results).
406		568
407	After creation, the condition variable is "false" until it becomes "true"	569	After creation, the condition variable is "false" until it becomes "true"
…		…
412	Condition variables are similar to callbacks, except that you can	574	Condition variables are similar to callbacks, except that you can
413	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
414	in time where multiple outstanding events have been processed. And yet	576	in time where multiple outstanding events have been processed. And yet
415	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
416	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
417	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.
418		581
419	Condition variables are very useful to signal that something has finished,	582	Condition variables are very useful to signal that something has finished,
420	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,
421	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
422	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
…		…
456	after => 1,	619	after => 1,
457	cb => sub { $result_ready->send },	620	cb => sub { $result_ready->send },
458	);	621	);
459		622
460	# this "blocks" (while handling events) till the callback	623	# this "blocks" (while handling events) till the callback
461	# calls send	624	# calls ->send
462	$result_ready->recv;	625	$result_ready->recv;
463		626
464	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
465	condition variables are also code references.	628	variables are also callable directly.
466		629
467	my $done = AnyEvent->condvar;	630	my $done = AnyEvent->condvar;
468	my $delay = AnyEvent->timer (after => 5, cb => $done);	631	my $delay = AnyEvent->timer (after => 5, cb => $done);
469	$done->recv;	632	$done->recv;
470		633
…		…
476		639
477	...	640	...
478		641
479	my @info = $couchdb->info->recv;	642	my @info = $couchdb->info->recv;
480		643
481	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
482	results are available:	645	results are available:
483		646
484	$couchdb->info->cb (sub {	647	$couchdb->info->cb (sub {
485	my @info = $_[0]->recv;	648	my @info = $_[0]->recv;
486	});	649	});
…		…
504	immediately from within send.	667	immediately from within send.
505		668
506	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
507	future C<< ->recv >> calls.	670	future C<< ->recv >> calls.
508		671
509	Condition variables are overloaded so one can call them directly	672	Condition variables are overloaded so one can call them directly (as if
510	(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
511	C<send>. Note, however, that many C-based event loops do not handle	674	C<send>.
512	overloading, so as tempting as it may be, passing a condition variable
513	instead of a callback does not work. Both the pure perl and EV loops
514	support overloading, however, as well as all functions that use perl to
515	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
516	example).
517		675
518	=item $cv->croak ($error)	676	=item $cv->croak ($error)
519		677
520	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
521	C<Carp::croak> with the given error message/object/scalar.	679	C<Carp::croak> with the given error message/object/scalar.
522		680
523	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
524	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.
525		687
526	=item $cv->begin ([group callback])	688	=item $cv->begin ([group callback])
527		689
528	=item $cv->end	690	=item $cv->end
529
530	These two methods are EXPERIMENTAL and MIGHT CHANGE.
531		691
532	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
533	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
534	to use a condition variable for the whole process.	694	to use a condition variable for the whole process.
535		695
536	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
537	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
538	>>, 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
539	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
540	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.
541		702
542	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:
543		710
544	my $cv = AnyEvent->condvar;	711	my $cv = AnyEvent->condvar;
545		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
546	my %result;	737	my %result;
547	$cv->begin (sub { $cv->send (\%result) });	738	$cv->begin (sub { shift->send (\%result) });
548		739
549	for my $host (@list_of_hosts) {	740	for my $host (@list_of_hosts) {
550	$cv->begin;	741	$cv->begin;
551	ping_host_then_call_callback $host, sub {	742	ping_host_then_call_callback $host, sub {
552	$result{$host} = ...;	743	$result{$host} = ...;
…		…
567	loop, which serves two important purposes: first, it sets the callback	758	loop, which serves two important purposes: first, it sets the callback
568	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
569	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
570	doesn't execute once).	761	doesn't execute once).
571		762
572	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
573	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
574	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
575	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>.
576		768
577	=back	769	=back
578		770
579	=head3 METHODS FOR CONSUMERS	771	=head3 METHODS FOR CONSUMERS
580		772
…		…
596	function will call C<croak>.	788	function will call C<croak>.
597		789
598	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,
599	in scalar context only the first one will be returned.	791	in scalar context only the first one will be returned.
600		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
601	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
602	(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
603	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
604	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
605	condition variables with some kind of request results and supporting	804	condition variables with some kind of request results and supporting
606	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,
607	while still supporting blocking waits if the caller so desires).	806	while still supporting blocking waits if the caller so desires).
608		807
609	Another reason I<never> to C<< ->recv >> in a module is that you cannot
610	sensibly have two C<< ->recv >>'s in parallel, as that would require
611	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
612	can supply.
613
614	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
615	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
616	versions and also integrates coroutines into AnyEvent, making blocking
617	C<< ->recv >> calls perfectly safe as long as they are done from another
618	coroutine (one that doesn't run the event loop).
619
620	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
621	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
622	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
623	waits otherwise.	811	waits otherwise.
624		812
…		…
630	=item $cb = $cv->cb ($cb->($cv))	818	=item $cb = $cv->cb ($cb->($cv))
631		819
632	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
633	replaces it before doing so.	821	replaces it before doing so.
634		822
635	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)
636	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
637	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>
638	is guaranteed not to block.	826	inside the callback or at any later time is guaranteed not to block.
639		827
640	=back	828	=back
641		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
642	=head1 GLOBAL VARIABLES AND FUNCTIONS	898	=head1 GLOBAL VARIABLES AND FUNCTIONS
643		899
		900	These are not normally required to use AnyEvent, but can be useful to
		901	write AnyEvent extension modules.
		902
644	=over 4	903	=over 4
645		904
646	=item $AnyEvent::MODEL	905	=item $AnyEvent::MODEL
647		906
648	Contains C<undef> until the first watcher is being created. Then it	907	Contains C<undef> until the first watcher is being created, before the
		908	backend has been autodetected.
		909
649	contains the event model that is being used, which is the name of the	910	Afterwards it contains the event model that is being used, which is the
650	Perl class implementing the model. This class is usually one of the	911	name of the Perl class implementing the model. This class is usually one
651	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	912	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
652	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	913	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
653		914	will be C<urxvt::anyevent>).
654	The known classes so far are:
655
656	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
657	AnyEvent::Impl::Event based on Event, second best choice.
658	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
659	AnyEvent::Impl::Glib based on Glib, third-best choice.
660	AnyEvent::Impl::Tk based on Tk, very bad choice.
661	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
662	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
663	AnyEvent::Impl::POE based on POE, not generic enough for full support.
664
665	There is no support for WxWidgets, as WxWidgets has no support for
666	watching file handles. However, you can use WxWidgets through the
667	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
668	second, which was considered to be too horrible to even consider for
669	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
670	it's adaptor.
671
672	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
673	autodetecting them.
674		915
675	=item AnyEvent::detect	916	=item AnyEvent::detect
676		917
677	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	918	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
678	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
679	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
680	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>.
681		925
682	=item $guard = AnyEvent::post_detect { BLOCK }	926	=item $guard = AnyEvent::post_detect { BLOCK }
683		927
684	Arranges for the code block to be executed as soon as the event model is	928	Arranges for the code block to be executed as soon as the event model is
685	autodetected (or immediately if this has already happened).	929	autodetected (or immediately if this has already happened).
686		930
		931	The block will be executed I<after> the actual backend has been detected
		932	(C<$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
687	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
688	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
689	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 ||= $guard;
690		962
691	=item @AnyEvent::post_detect	963	=item @AnyEvent::post_detect
692		964
693	If there are any code references in this array (you can C<push> to it	965	If there are any code references in this array (you can C<push> to it
694	before or after loading AnyEvent), then they will called directly after	966	before or after loading AnyEvent), then they will called directly after
695	the event loop has been chosen.	967	the event loop has been chosen.
696		968
697	You should check C<$AnyEvent::MODEL> before adding to this array, though:	969	You should check C<$AnyEvent::MODEL> before adding to this array, though:
698	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
699	and the array will be ignored.	971	array will be ignored.
700		972
701	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	}
702		993
703	=back	994	=back
704		995
705	=head1 WHAT TO DO IN A MODULE	996	=head1 WHAT TO DO IN A MODULE
706		997
…		…
761		1052
762		1053
763	=head1 OTHER MODULES	1054	=head1 OTHER MODULES
764		1055
765	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
766	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
767	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
768	available via CPAN.	1059	come with AnyEvent, most are available via CPAN.
769		1060
770	=over 4	1061	=over 4
771		1062
772	=item L<AnyEvent::Util>	1063	=item L<AnyEvent::Util>
773		1064
…		…
782		1073
783	=item L<AnyEvent::Handle>	1074	=item L<AnyEvent::Handle>
784		1075
785	Provide read and write buffers, manages watchers for reads and writes,	1076	Provide read and write buffers, manages watchers for reads and writes,
786	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
787	non-blocking SSL/TLS.	1078	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
788		1079
789	=item L<AnyEvent::DNS>	1080	=item L<AnyEvent::DNS>
790		1081
791	Provides rich asynchronous DNS resolver capabilities.	1082	Provides rich asynchronous DNS resolver capabilities.
792		1083
…		…
820		1111
821	=item L<AnyEvent::GPSD>	1112	=item L<AnyEvent::GPSD>
822		1113
823	A non-blocking interface to gpsd, a daemon delivering GPS information.	1114	A non-blocking interface to gpsd, a daemon delivering GPS information.
824		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
825	=item L<AnyEvent::IGS>	1125	=item L<AnyEvent::IGS>
826		1126
827	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
828	L<App::IGS>).	1128	L<App::IGS>).
829		1129
830	=item L<AnyEvent::IRC>
831
832	AnyEvent based IRC client module family (replacing the older Net::IRC3).
833
834	=item L<Net::XMPP2>
835
836	AnyEvent based XMPP (Jabber protocol) module family.
837
838	=item L<Net::FCP>	1130	=item L<Net::FCP>
839		1131
840	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1132	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
841	of AnyEvent.	1133	of AnyEvent.
842		1134
…		…
846		1138
847	=item L<Coro>	1139	=item L<Coro>
848		1140
849	Has special support for AnyEvent via L<Coro::AnyEvent>.	1141	Has special support for AnyEvent via L<Coro::AnyEvent>.
850		1142
851	=item L<IO::Lambda>
852
853	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
854
855	=back	1143	=back
856		1144
857	=cut	1145	=cut
858		1146
859	package AnyEvent;	1147	package AnyEvent;
860		1148
861	no warnings;	1149	# basically a tuned-down version of common::sense
862	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	}
863		1156
		1157	BEGIN { AnyEvent::common_sense }
		1158
864	use Carp;	1159	use Carp ();
865		1160
866	our $VERSION = 4.34;	1161	our $VERSION = '5.24';
867	our $MODEL;	1162	our $MODEL;
868		1163
869	our $AUTOLOAD;	1164	our $AUTOLOAD;
870	our @ISA;	1165	our @ISA;
871		1166
872	our @REGISTRY;	1167	our @REGISTRY;
873		1168
874	our $WIN32;	1169	our $VERBOSE;
875		1170
876	BEGIN {	1171	BEGIN {
877	my $win32 = ! ! ($^O =~ /mswin32/i);	1172	eval "sub CYGWIN(){" . (($^O =~ /cygwin/i) *1) . "}";
878	eval "sub WIN32(){ $win32 }";	1173	eval "sub WIN32 (){" . (($^O =~ /mswin32/i)*1) . "}";
879	}	1174	eval "sub TAINT (){" . (${^TAINT} *1) . "}";
880		1175
		1176	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1177	if ${^TAINT};
		1178
881	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1179	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1180
		1181	}
		1182
		1183	our $MAX_SIGNAL_LATENCY = 10;
882		1184
883	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1185	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
884		1186
885	{	1187	{
886	my $idx;	1188	my $idx;
…		…
888	for reverse split /\s*,\s*/,	1190	for reverse split /\s*,\s*/,
889	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1191	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
890	}	1192	}
891		1193
892	my @models = (	1194	my @models = (
893	[EV:: => AnyEvent::Impl::EV::],	1195	[EV:: => AnyEvent::Impl::EV:: , 1],
894	[Event:: => AnyEvent::Impl::Event::],
895	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1196	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
896	# everything below here will not be autoprobed	1197	# everything below here will not (normally) be autoprobed
897	# as the pureperl backend should work everywhere	1198	# as the pureperl backend should work everywhere
898	# 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
899	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1204	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
900	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
901	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
902	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1205	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
903	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1206	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
904	[Wx:: => AnyEvent::Impl::POE::],	1207	[Wx:: => AnyEvent::Impl::POE::],
905	[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
906	);	1217	);
907		1218
908	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1219	our %method = map +($_ => 1),
		1220	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
909		1221
910	our @post_detect;	1222	our @post_detect;
911		1223
912	sub post_detect(&) {	1224	sub post_detect(&) {
913	my ($cb) = @_;	1225	my ($cb) = @_;
914		1226
915	if ($MODEL) {	1227	if ($MODEL) {
916	$cb->();	1228	$cb->();
917		1229
918	1	1230	undef
919	} else {	1231	} else {
920	push @post_detect, $cb;	1232	push @post_detect, $cb;
921		1233
922	defined wantarray	1234	defined wantarray
923	? bless \$cb, "AnyEvent::Util::PostDetect"	1235	? bless \$cb, "AnyEvent::Util::postdetect"
924	: ()	1236	: ()
925	}	1237	}
926	}	1238	}
927		1239
928	sub AnyEvent::Util::PostDetect::DESTROY {	1240	sub AnyEvent::Util::postdetect::DESTROY {
929	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1241	@post_detect = grep $_ != ${$_[0]}, @post_detect;
930	}	1242	}
931		1243
932	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 $VERBOSE;
		1258	}
		1259	}
		1260
		1261	# check for already loaded models
933	unless ($MODEL) {	1262	unless ($MODEL) {
934	no strict 'refs';	1263	for (@REGISTRY, @models) {
935	local $SIG{__DIE__};	1264	my ($package, $model) = @$_;
936		1265	if (${"$package\::VERSION"} > 0) {
937	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
938	my $model = "AnyEvent::Impl::$1";
939	if (eval "require $model") {	1266	if (eval "require $model") {
940	$MODEL = $model;	1267	$MODEL = $model;
941	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1268	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
942	} else {	1269	last;
943	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1270	}
944	}	1271	}
945	}	1272	}
946		1273
947	# check for already loaded models
948	unless ($MODEL) {	1274	unless ($MODEL) {
		1275	# try to autoload a model
949	for (@REGISTRY, @models) {	1276	for (@REGISTRY, @models) {
950	my ($package, $model) = @$_;	1277	my ($package, $model, $autoload) = @$_;
		1278	if (
		1279	$autoload
		1280	and eval "require $package"
951	if (${"$package\::VERSION"} > 0) {	1281	and ${"$package\::VERSION"} > 0
952	if (eval "require $model") {	1282	and eval "require $model"
		1283	) {
953	$MODEL = $model;	1284	$MODEL = $model;
954	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1285	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
955	last;	1286	last;
956	}
957	}	1287	}
958	}	1288	}
959		1289
960	unless ($MODEL) {
961	# try to load a model
962
963	for (@REGISTRY, @models) {
964	my ($package, $model) = @$_;
965	if (eval "require $package"
966	and ${"$package\::VERSION"} > 0
967	and eval "require $model") {
968	$MODEL = $model;
969	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
970	last;
971	}
972	}
973
974	$MODEL	1290	$MODEL
975	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1291	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
976	}
977	}	1292	}
978
979	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
980
981	unshift @ISA, $MODEL;
982
983	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
984
985	(shift @post_detect)->() while @post_detect;
986	}	1293	}
		1294
		1295	@models = (); # free probe data
		1296
		1297	push @{"$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;
987		1303
988	$MODEL	1304	$MODEL
989	}	1305	}
990		1306
991	sub AUTOLOAD {	1307	sub AUTOLOAD {
992	(my $func = $AUTOLOAD) =~ s/.*://;	1308	(my $func = $AUTOLOAD) =~ s/.*://;
993		1309
994	$method{$func}	1310	$method{$func}
995	or croak "$func: not a valid method for AnyEvent objects";	1311	or Carp::croak "$func: not a valid AnyEvent class method";
996		1312
997	detect unless $MODEL;	1313	detect;
998		1314
999	my $class = shift;	1315	my $class = shift;
1000	$class->$func (@_);	1316	$class->$func (@_);
1001	}	1317	}
1002		1318
1003	# 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
1004	# to support binding more than one watcher per filehandle (they usually	1320	# to support binding more than one watcher per filehandle (they usually
1005	# 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).
1006	sub _dupfh($$$$) {	1322	sub _dupfh($$;$$) {
1007	my ($poll, $fh, $r, $w) = @_;	1323	my ($poll, $fh, $r, $w) = @_;
1008		1324
1009	require Fcntl;
1010
1011	# cygwin requires the fh mode to be matching, unix doesn't	1325	# cygwin requires the fh mode to be matching, unix doesn't
1012	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1326	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1013	: $poll eq "w" ? ($w, ">")
1014	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1015		1327
1016	open my $fh2, "$mode&" . fileno $fh	1328	open my $fh2, $mode, $fh
1017	or die "cannot dup() filehandle: $!";	1329	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1018		1330
1019	# we assume CLOEXEC is already set by perl in all important cases	1331	# we assume CLOEXEC is already set by perl in all important cases
1020		1332
1021	($fh2, $rw)	1333	($fh2, $rw)
1022	}	1334	}
1023		1335
		1336	=head1 SIMPLIFIED AE API
		1337
		1338	Starting with version 5.0, AnyEvent officially supports a second, much
		1339	simpler, API that is designed to reduce the calling, typing and memory
		1340	overhead.
		1341
		1342	See the L<AE> manpage for details.
		1343
		1344	=cut
		1345
		1346	package AE;
		1347
		1348	our $VERSION = $AnyEvent::VERSION;
		1349
		1350	sub io($$$) {
		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
1024	package AnyEvent::Base;	1386	package AnyEvent::Base;
1025		1387
1026	# default implementation for now and time	1388	# default implementations for many methods
1027		1389
1028	BEGIN {	1390	sub _time() {
		1391	eval q{ # poor man's autoloading
		1392	# probe for availability of Time::HiRes
1029	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;
1030	*_time = \&Time::HiRes::time;	1395	*_time = \&Time::HiRes::time;
1031	# if (eval "use POSIX (); (POSIX::times())...	1396	# if (eval "use POSIX (); (POSIX::times())...
1032	} else {	1397	} else {
		1398	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1033	*_time = sub { time }; # epic fail	1399	*_time = sub (){ time }; # epic fail
		1400	}
1034	}	1401	};
		1402	die if $@;
		1403
		1404	&_time
1035	}	1405	}
1036		1406
1037	sub time { _time }	1407	sub time { _time }
1038	sub now { _time }	1408	sub now { _time }
		1409	sub now_update { }
1039		1410
1040	# default implementation for ->condvar	1411	# default implementation for ->condvar
1041		1412
1042	sub condvar {	1413	sub condvar {
1043	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1414	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1044	}	1415	}
1045		1416
1046	# default implementation for ->signal	1417	# default implementation for ->signal
1047		1418
1048	our %SIG_CB;	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
		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);
		1432
		1433	# install a dummy wakeup watcher to reduce signal catching latency
		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;
		1439
		1440	$SIG_TW = AE::timer
		1441	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1442	$MAX_SIGNAL_LATENCY,
		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	};
		1476	}
		1477	};
		1478	die if $@;
		1479	};
		1480
		1481	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1482	sub sig2name($) { &$_sig_name_init; &sig2name }
1049		1483
1050	sub signal {	1484	sub signal {
		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;
		1489
		1490	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1491	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
		1492
		1493	} else {
		1494	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1495
		1496	require Fcntl;
		1497
		1498	if (AnyEvent::WIN32) {
		1499	require AnyEvent::Util;
		1500
		1501	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1502	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1503	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1504	} else {
		1505	pipe $SIGPIPE_R, $SIGPIPE_W;
		1506	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1507	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1508
		1509	# not strictly required, as $^F is normally 2, but let's make sure...
		1510	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1511	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1512	}
		1513
		1514	$SIGPIPE_R
		1515	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1516
		1517	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
		1518	}
		1519
		1520	*signal = sub {
1051	my (undef, %arg) = @_;	1521	my (undef, %arg) = @_;
1052		1522
1053	my $signal = uc $arg{signal}	1523	my $signal = uc $arg{signal}
1054	or Carp::croak "required option 'signal' is missing";	1524	or Carp::croak "required option 'signal' is missing";
1055		1525
		1526	if ($HAVE_ASYNC_INTERRUPT) {
		1527	# async::interrupt
		1528
		1529	$signal = sig2num $signal;
1056	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1530	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1531
		1532	$SIG_ASY{$signal} ||= new Async::Interrupt
		1533	cb => sub { undef $SIG_EV{$signal} },
		1534	signal => $signal,
		1535	pipe => [$SIGPIPE_R->filenos],
		1536	pipe_autodrain => 0,
		1537	;
		1538
		1539	} else {
		1540	# pure perl
		1541
		1542	# AE::Util has been loaded in signal
		1543	$signal = sig2name $signal;
		1544	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1545
1057	$SIG{$signal} ||= sub {	1546	$SIG{$signal} ||= sub {
		1547	local $!;
		1548	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1549	undef $SIG_EV{$signal};
		1550	};
		1551
		1552	# can't do signal processing without introducing races in pure perl,
		1553	# so limit the signal latency.
		1554	_sig_add;
		1555	}
		1556
		1557	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1558	};
		1559
		1560	*AnyEvent::Base::signal::DESTROY = sub {
		1561	my ($signal, $cb) = @{$_[0]};
		1562
		1563	_sig_del;
		1564
		1565	delete $SIG_CB{$signal}{$cb};
		1566
		1567	$HAVE_ASYNC_INTERRUPT
		1568	? delete $SIG_ASY{$signal}
		1569	: # delete doesn't work with older perls - they then
		1570	# print weird messages, or just unconditionally exit
		1571	# instead of getting the default action.
		1572	undef $SIG{$signal}
		1573	unless keys %{ $SIG_CB{$signal} };
		1574	};
		1575
		1576	*_signal_exec = sub {
		1577	$HAVE_ASYNC_INTERRUPT
		1578	? $SIGPIPE_R->drain
		1579	: sysread $SIGPIPE_R, (my $dummy), 9;
		1580
		1581	while (%SIG_EV) {
		1582	for (keys %SIG_EV) {
		1583	delete $SIG_EV{$_};
1058	$_->() for values %{ $SIG_CB{$signal} || {} };	1584	$_->() for values %{ $SIG_CB{$_} || {} };
		1585	}
		1586	}
		1587	};
1059	};	1588	};
		1589	die if $@;
1060		1590
1061	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1591	&signal
1062	}
1063
1064	sub AnyEvent::Base::Signal::DESTROY {
1065	my ($signal, $cb) = @{$_[0]};
1066
1067	delete $SIG_CB{$signal}{$cb};
1068
1069	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1070	}	1592	}
1071		1593
1072	# default implementation for ->child	1594	# default implementation for ->child
1073		1595
1074	our %PID_CB;	1596	our %PID_CB;
1075	our $CHLD_W;	1597	our $CHLD_W;
1076	our $CHLD_DELAY_W;	1598	our $CHLD_DELAY_W;
1077	our $PID_IDLE;
1078	our $WNOHANG;	1599	our $WNOHANG;
1079		1600
1080	sub _child_wait {	1601	# used by many Impl's
1081	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1602	sub _emit_childstatus($$) {
		1603	my (undef, $rpid, $rstatus) = @_;
		1604
		1605	$_->($rpid, $rstatus)
1082	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1606	for values %{ $PID_CB{$rpid} || {} },
1083	(values %{ $PID_CB{0} || {} });	1607	values %{ $PID_CB{0} || {} };
1084	}
1085
1086	undef $PID_IDLE;
1087	}
1088
1089	sub _sigchld {
1090	# make sure we deliver these changes "synchronous" with the event loop.
1091	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
1092	undef $CHLD_DELAY_W;
1093	&_child_wait;
1094	});
1095	}	1608	}
1096		1609
1097	sub child {	1610	sub child {
		1611	eval q{ # poor man's autoloading {}
		1612	*_sigchld = sub {
		1613	my $pid;
		1614
		1615	AnyEvent->_emit_childstatus ($pid, $?)
		1616	while ($pid = waitpid -1, $WNOHANG) > 0;
		1617	};
		1618
		1619	*child = sub {
1098	my (undef, %arg) = @_;	1620	my (undef, %arg) = @_;
1099		1621
1100	defined (my $pid = $arg{pid} + 0)	1622	defined (my $pid = $arg{pid} + 0)
1101	or Carp::croak "required option 'pid' is missing";	1623	or Carp::croak "required option 'pid' is missing";
1102		1624
1103	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1625	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1104		1626
1105	unless ($WNOHANG) {	1627	# WNOHANG is almost cetrainly 1 everywhere
		1628	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1629	? 1
1106	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1630	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1107	}
1108		1631
1109	unless ($CHLD_W) {	1632	unless ($CHLD_W) {
1110	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1633	$CHLD_W = AE::signal CHLD => \&_sigchld;
1111	# child could be a zombie already, so make at least one round	1634	# child could be a zombie already, so make at least one round
1112	&_sigchld;	1635	&_sigchld;
1113	}	1636	}
1114		1637
1115	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1638	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1116	}	1639	};
1117		1640
1118	sub AnyEvent::Base::Child::DESTROY {	1641	*AnyEvent::Base::child::DESTROY = sub {
1119	my ($pid, $cb) = @{$_[0]};	1642	my ($pid, $cb) = @{$_[0]};
1120		1643
1121	delete $PID_CB{$pid}{$cb};	1644	delete $PID_CB{$pid}{$cb};
1122	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1645	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1123		1646
1124	undef $CHLD_W unless keys %PID_CB;	1647	undef $CHLD_W unless keys %PID_CB;
		1648	};
		1649	};
		1650	die if $@;
		1651
		1652	&child
		1653	}
		1654
		1655	# idle emulation is done by simply using a timer, regardless
		1656	# of whether the process is idle or not, and not letting
		1657	# the callback use more than 50% of the time.
		1658	sub idle {
		1659	eval q{ # poor man's autoloading {}
		1660	*idle = sub {
		1661	my (undef, %arg) = @_;
		1662
		1663	my ($cb, $w, $rcb) = $arg{cb};
		1664
		1665	$rcb = sub {
		1666	if ($cb) {
		1667	$w = _time;
		1668	&$cb;
		1669	$w = _time - $w;
		1670
		1671	# never use more then 50% of the time for the idle watcher,
		1672	# within some limits
		1673	$w = 0.0001 if $w < 0.0001;
		1674	$w = 5 if $w > 5;
		1675
		1676	$w = AE::timer $w, 0, $rcb;
		1677	} else {
		1678	# clean up...
		1679	undef $w;
		1680	undef $rcb;
		1681	}
		1682	};
		1683
		1684	$w = AE::timer 0.05, 0, $rcb;
		1685
		1686	bless \\$cb, "AnyEvent::Base::idle"
		1687	};
		1688
		1689	*AnyEvent::Base::idle::DESTROY = sub {
		1690	undef $${$_[0]};
		1691	};
		1692	};
		1693	die if $@;
		1694
		1695	&idle
1125	}	1696	}
1126		1697
1127	package AnyEvent::CondVar;	1698	package AnyEvent::CondVar;
1128		1699
1129	our @ISA = AnyEvent::CondVar::Base::;	1700	our @ISA = AnyEvent::CondVar::Base::;
1130		1701
1131	package AnyEvent::CondVar::Base;	1702	package AnyEvent::CondVar::Base;
1132		1703
1133	use overload	1704	#use overload
1134	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1705	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1135	fallback => 1;	1706	# fallback => 1;
		1707
		1708	# save 300+ kilobytes by dirtily hardcoding overloading
		1709	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1710	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1711	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1712	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1713
		1714	our $WAITING;
1136		1715
1137	sub _send {	1716	sub _send {
1138	# nop	1717	# nop
1139	}	1718	}
1140		1719
…		…
1153	sub ready {	1732	sub ready {
1154	$_[0]{_ae_sent}	1733	$_[0]{_ae_sent}
1155	}	1734	}
1156		1735
1157	sub _wait {	1736	sub _wait {
		1737	$WAITING
		1738	and !$_[0]{_ae_sent}
		1739	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1740
		1741	local $WAITING = 1;
1158	AnyEvent->one_event while !$_[0]{_ae_sent};	1742	AnyEvent->one_event while !$_[0]{_ae_sent};
1159	}	1743	}
1160		1744
1161	sub recv {	1745	sub recv {
1162	$_[0]->_wait;	1746	$_[0]->_wait;
…		…
1164	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1748	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1165	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1749	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1166	}	1750	}
1167		1751
1168	sub cb {	1752	sub cb {
1169	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1753	my $cv = shift;
		1754
		1755	@_
		1756	and $cv->{_ae_cb} = shift
		1757	and $cv->{_ae_sent}
		1758	and (delete $cv->{_ae_cb})->($cv);
		1759
1170	$_[0]{_ae_cb}	1760	$cv->{_ae_cb}
1171	}	1761	}
1172		1762
1173	sub begin {	1763	sub begin {
1174	++$_[0]{_ae_counter};	1764	++$_[0]{_ae_counter};
1175	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1765	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1203	so on.	1793	so on.
1204		1794
1205	=head1 ENVIRONMENT VARIABLES	1795	=head1 ENVIRONMENT VARIABLES
1206		1796
1207	The following environment variables are used by this module or its	1797	The following environment variables are used by this module or its
1208	submodules:	1798	submodules.
		1799
		1800	Note that AnyEvent will remove I<all> environment variables starting with
		1801	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1802	enabled.
1209		1803
1210	=over 4	1804	=over 4
1211		1805
1212	=item C<PERL_ANYEVENT_VERBOSE>	1806	=item C<PERL_ANYEVENT_VERBOSE>
1213		1807
…		…
1220	C<PERL_ANYEVENT_MODEL>.	1814	C<PERL_ANYEVENT_MODEL>.
1221		1815
1222	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1816	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1223	model it chooses.	1817	model it chooses.
1224		1818
		1819	When set to C<8> or higher, then AnyEvent will report extra information on
		1820	which optional modules it loads and how it implements certain features.
		1821
1225	=item C<PERL_ANYEVENT_STRICT>	1822	=item C<PERL_ANYEVENT_STRICT>
1226		1823
1227	AnyEvent does not do much argument checking by default, as thorough	1824	AnyEvent does not do much argument checking by default, as thorough
1228	argument checking is very costly. Setting this variable to a true value	1825	argument checking is very costly. Setting this variable to a true value
1229	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1826	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1230	check the arguments passed to most method calls. If it finds any problems	1827	check the arguments passed to most method calls. If it finds any problems,
1231	it will croak.	1828	it will croak.
1232		1829
1233	In other words, enables "strict" mode.	1830	In other words, enables "strict" mode.
1234		1831
1235	Unlike C<use strict>, it is definitely recommended ot keep it off in	1832	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1236	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1833	>>, it is definitely recommended to keep it off in production. Keeping
1237	developing programs can be very useful, however.	1834	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1835	can be very useful, however.
1238		1836
1239	=item C<PERL_ANYEVENT_MODEL>	1837	=item C<PERL_ANYEVENT_MODEL>
1240		1838
1241	This can be used to specify the event model to be used by AnyEvent, before	1839	This can be used to specify the event model to be used by AnyEvent, before
1242	auto detection and -probing kicks in. It must be a string consisting	1840	auto detection and -probing kicks in. It must be a string consisting
…		…
1285		1883
1286	=item C<PERL_ANYEVENT_MAX_FORKS>	1884	=item C<PERL_ANYEVENT_MAX_FORKS>
1287		1885
1288	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1886	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1289	will create in parallel.	1887	will create in parallel.
		1888
		1889	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1890
		1891	The default value for the C<max_outstanding> parameter for the default DNS
		1892	resolver - this is the maximum number of parallel DNS requests that are
		1893	sent to the DNS server.
		1894
		1895	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1896
		1897	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1898	configuration) in the default resolver. When set to the empty string, no
		1899	default config will be used.
		1900
		1901	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1902
		1903	When neither C<ca_file> nor C<ca_path> was specified during
		1904	L<AnyEvent::TLS> context creation, and either of these environment
		1905	variables exist, they will be used to specify CA certificate locations
		1906	instead of a system-dependent default.
		1907
		1908	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1909
		1910	When these are set to C<1>, then the respective modules are not
		1911	loaded. Mostly good for testing AnyEvent itself.
1290		1912
1291	=back	1913	=back
1292		1914
1293	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1915	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1294		1916
…		…
1352	warn "read: $input\n"; # output what has been read	1974	warn "read: $input\n"; # output what has been read
1353	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1975	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1354	},	1976	},
1355	);	1977	);
1356		1978
1357	my $time_watcher; # can only be used once
1358
1359	sub new_timer {
1360	$timer = AnyEvent->timer (after => 1, cb => sub {	1979	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1361	warn "timeout\n"; # print 'timeout' about every second	1980	warn "timeout\n"; # print 'timeout' at most every second
1362	&new_timer; # and restart the time
1363	});	1981	});
1364	}
1365
1366	new_timer; # create first timer
1367		1982
1368	$cv->recv; # wait until user enters /^q/i	1983	$cv->recv; # wait until user enters /^q/i
1369		1984
1370	=head1 REAL-WORLD EXAMPLE	1985	=head1 REAL-WORLD EXAMPLE
1371		1986
…		…
1502	through AnyEvent. The benchmark creates a lot of timers (with a zero	2117	through AnyEvent. The benchmark creates a lot of timers (with a zero
1503	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2118	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1504	which it is), lets them fire exactly once and destroys them again.	2119	which it is), lets them fire exactly once and destroys them again.
1505		2120
1506	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2121	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1507	distribution.	2122	distribution. It uses the L<AE> interface, which makes a real difference
		2123	for the EV and Perl backends only.
1508		2124
1509	=head3 Explanation of the columns	2125	=head3 Explanation of the columns
1510		2126
1511	I<watcher> is the number of event watchers created/destroyed. Since	2127	I<watcher> is the number of event watchers created/destroyed. Since
1512	different event models feature vastly different performances, each event	2128	different event models feature vastly different performances, each event
…		…
1533	watcher.	2149	watcher.
1534		2150
1535	=head3 Results	2151	=head3 Results
1536		2152
1537	name watchers bytes create invoke destroy comment	2153	name watchers bytes create invoke destroy comment
1538	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2154	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1539	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2155	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1540	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2156	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1541	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2157	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1542	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2158	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1543	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2159	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2160	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2161	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1544	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2162	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1545	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2163	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1546	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2164	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1547	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2165	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1548		2166
1549	=head3 Discussion	2167	=head3 Discussion
1550		2168
1551	The benchmark does I<not> measure scalability of the event loop very	2169	The benchmark does I<not> measure scalability of the event loop very
1552	well. For example, a select-based event loop (such as the pure perl one)	2170	well. For example, a select-based event loop (such as the pure perl one)
…		…
1564	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2182	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1565	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2183	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1566	cycles with POE.	2184	cycles with POE.
1567		2185
1568	C<EV> is the sole leader regarding speed and memory use, which are both	2186	C<EV> is the sole leader regarding speed and memory use, which are both
1569	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2187	maximal/minimal, respectively. When using the L<AE> API there is zero
		2188	overhead (when going through the AnyEvent API create is about 5-6 times
		2189	slower, with other times being equal, so still uses far less memory than
1570	far less memory than any other event loop and is still faster than Event	2190	any other event loop and is still faster than Event natively).
1571	natively.
1572		2191
1573	The pure perl implementation is hit in a few sweet spots (both the	2192	The pure perl implementation is hit in a few sweet spots (both the
1574	constant timeout and the use of a single fd hit optimisations in the perl	2193	constant timeout and the use of a single fd hit optimisations in the perl
1575	interpreter and the backend itself). Nevertheless this shows that it	2194	interpreter and the backend itself). Nevertheless this shows that it
1576	adds very little overhead in itself. Like any select-based backend its	2195	adds very little overhead in itself. Like any select-based backend its
1577	performance becomes really bad with lots of file descriptors (and few of	2196	performance becomes really bad with lots of file descriptors (and few of
1578	them active), of course, but this was not subject of this benchmark.	2197	them active), of course, but this was not subject of this benchmark.
1579		2198
1580	The C<Event> module has a relatively high setup and callback invocation	2199	The C<Event> module has a relatively high setup and callback invocation
1581	cost, but overall scores in on the third place.	2200	cost, but overall scores in on the third place.
		2201
		2202	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2203	when using its pure perl backend.
1582		2204
1583	C<Glib>'s memory usage is quite a bit higher, but it features a	2205	C<Glib>'s memory usage is quite a bit higher, but it features a
1584	faster callback invocation and overall ends up in the same class as	2206	faster callback invocation and overall ends up in the same class as
1585	C<Event>. However, Glib scales extremely badly, doubling the number of	2207	C<Event>. However, Glib scales extremely badly, doubling the number of
1586	watchers increases the processing time by more than a factor of four,	2208	watchers increases the processing time by more than a factor of four,
…		…
1647	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2269	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1648	(1%) are active. This mirrors the activity of large servers with many	2270	(1%) are active. This mirrors the activity of large servers with many
1649	connections, most of which are idle at any one point in time.	2271	connections, most of which are idle at any one point in time.
1650		2272
1651	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2273	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1652	distribution.	2274	distribution. It uses the L<AE> interface, which makes a real difference
		2275	for the EV and Perl backends only.
1653		2276
1654	=head3 Explanation of the columns	2277	=head3 Explanation of the columns
1655		2278
1656	I<sockets> is the number of sockets, and twice the number of "servers" (as	2279	I<sockets> is the number of sockets, and twice the number of "servers" (as
1657	each server has a read and write socket end).	2280	each server has a read and write socket end).
…		…
1664	it to another server. This includes deleting the old timeout and creating	2287	it to another server. This includes deleting the old timeout and creating
1665	a new one that moves the timeout into the future.	2288	a new one that moves the timeout into the future.
1666		2289
1667	=head3 Results	2290	=head3 Results
1668		2291
1669	name sockets create request	2292	name sockets create request
1670	EV 20000 69.01 11.16	2293	EV 20000 62.66 7.99
1671	Perl 20000 73.32 35.87	2294	Perl 20000 68.32 32.64
1672	Event 20000 212.62 257.32	2295	IOAsync 20000 174.06 101.15 epoll
1673	Glib 20000 651.16 1896.30	2296	IOAsync 20000 174.67 610.84 poll
		2297	Event 20000 202.69 242.91
		2298	Glib 20000 557.01 1689.52
1674	POE 20000 349.67 12317.24 uses POE::Loop::Event	2299	POE 20000 341.54 12086.32 uses POE::Loop::Event
1675		2300
1676	=head3 Discussion	2301	=head3 Discussion
1677		2302
1678	This benchmark I<does> measure scalability and overall performance of the	2303	This benchmark I<does> measure scalability and overall performance of the
1679	particular event loop.	2304	particular event loop.
…		…
1681	EV is again fastest. Since it is using epoll on my system, the setup time	2306	EV is again fastest. Since it is using epoll on my system, the setup time
1682	is relatively high, though.	2307	is relatively high, though.
1683		2308
1684	Perl surprisingly comes second. It is much faster than the C-based event	2309	Perl surprisingly comes second. It is much faster than the C-based event
1685	loops Event and Glib.	2310	loops Event and Glib.
		2311
		2312	IO::Async performs very well when using its epoll backend, and still quite
		2313	good compared to Glib when using its pure perl backend.
1686		2314
1687	Event suffers from high setup time as well (look at its code and you will	2315	Event suffers from high setup time as well (look at its code and you will
1688	understand why). Callback invocation also has a high overhead compared to	2316	understand why). Callback invocation also has a high overhead compared to
1689	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2317	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1690	uses select or poll in basically all documented configurations.	2318	uses select or poll in basically all documented configurations.
…		…
1753	=item * C-based event loops perform very well with small number of	2381	=item * C-based event loops perform very well with small number of
1754	watchers, as the management overhead dominates.	2382	watchers, as the management overhead dominates.
1755		2383
1756	=back	2384	=back
1757		2385
		2386	=head2 THE IO::Lambda BENCHMARK
		2387
		2388	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2389	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2390	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2391	shouldn't come as a surprise to anybody). As such, the benchmark is
		2392	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2393	very optimal. But how would AnyEvent compare when used without the extra
		2394	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2395
		2396	The benchmark itself creates an echo-server, and then, for 500 times,
		2397	connects to the echo server, sends a line, waits for the reply, and then
		2398	creates the next connection. This is a rather bad benchmark, as it doesn't
		2399	test the efficiency of the framework or much non-blocking I/O, but it is a
		2400	benchmark nevertheless.
		2401
		2402	name runtime
		2403	Lambda/select 0.330 sec
		2404	+ optimized 0.122 sec
		2405	Lambda/AnyEvent 0.327 sec
		2406	+ optimized 0.138 sec
		2407	Raw sockets/select 0.077 sec
		2408	POE/select, components 0.662 sec
		2409	POE/select, raw sockets 0.226 sec
		2410	POE/select, optimized 0.404 sec
		2411
		2412	AnyEvent/select/nb 0.085 sec
		2413	AnyEvent/EV/nb 0.068 sec
		2414	+state machine 0.134 sec
		2415
		2416	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2417	benchmarks actually make blocking connects and use 100% blocking I/O,
		2418	defeating the purpose of an event-based solution. All of the newly
		2419	written AnyEvent benchmarks use 100% non-blocking connects (using
		2420	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2421	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2422	generally require a lot more bookkeeping and event handling than blocking
		2423	connects (which involve a single syscall only).
		2424
		2425	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2426	offers similar expressive power as POE and IO::Lambda, using conventional
		2427	Perl syntax. This means that both the echo server and the client are 100%
		2428	non-blocking, further placing it at a disadvantage.
		2429
		2430	As you can see, the AnyEvent + EV combination even beats the
		2431	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2432	backend easily beats IO::Lambda and POE.
		2433
		2434	And even the 100% non-blocking version written using the high-level (and
		2435	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2436	higher level ("unoptimised") abstractions by a large margin, even though
		2437	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
		2438
		2439	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2440	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2441	part of the IO::Lambda distribution and were used without any changes.
		2442
1758		2443
1759	=head1 SIGNALS	2444	=head1 SIGNALS
1760		2445
1761	AnyEvent currently installs handlers for these signals:	2446	AnyEvent currently installs handlers for these signals:
1762		2447
…		…
1765	=item SIGCHLD	2450	=item SIGCHLD
1766		2451
1767	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2452	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1768	emulation for event loops that do not support them natively. Also, some	2453	emulation for event loops that do not support them natively. Also, some
1769	event loops install a similar handler.	2454	event loops install a similar handler.
		2455
		2456	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2457	AnyEvent will reset it to default, to avoid losing child exit statuses.
1770		2458
1771	=item SIGPIPE	2459	=item SIGPIPE
1772		2460
1773	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2461	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1774	when AnyEvent gets loaded.	2462	when AnyEvent gets loaded.
…		…
1786		2474
1787	=back	2475	=back
1788		2476
1789	=cut	2477	=cut
1790		2478
		2479	undef $SIG{CHLD}
		2480	if $SIG{CHLD} eq 'IGNORE';
		2481
1791	$SIG{PIPE} = sub { }	2482	$SIG{PIPE} = sub { }
1792	unless defined $SIG{PIPE};	2483	unless defined $SIG{PIPE};
1793		2484
		2485	=head1 RECOMMENDED/OPTIONAL MODULES
		2486
		2487	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2488	it's built-in modules) are required to use it.
		2489
		2490	That does not mean that AnyEvent won't take advantage of some additional
		2491	modules if they are installed.
		2492
		2493	This section explains which additional modules will be used, and how they
		2494	affect AnyEvent's operation.
		2495
		2496	=over 4
		2497
		2498	=item L<Async::Interrupt>
		2499
		2500	This slightly arcane module is used to implement fast signal handling: To
		2501	my knowledge, there is no way to do completely race-free and quick
		2502	signal handling in pure perl. To ensure that signals still get
		2503	delivered, AnyEvent will start an interval timer to wake up perl (and
		2504	catch the signals) with some delay (default is 10 seconds, look for
		2505	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2506
		2507	If this module is available, then it will be used to implement signal
		2508	catching, which means that signals will not be delayed, and the event loop
		2509	will not be interrupted regularly, which is more efficient (and good for
		2510	battery life on laptops).
		2511
		2512	This affects not just the pure-perl event loop, but also other event loops
		2513	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2514
		2515	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2516	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2517	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2518	does nothing for those backends.
		2519
		2520	=item L<EV>
		2521
		2522	This module isn't really "optional", as it is simply one of the backend
		2523	event loops that AnyEvent can use. However, it is simply the best event
		2524	loop available in terms of features, speed and stability: It supports
		2525	the AnyEvent API optimally, implements all the watcher types in XS, does
		2526	automatic timer adjustments even when no monotonic clock is available,
		2527	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2528	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2529	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2530
		2531	=item L<Guard>
		2532
		2533	The guard module, when used, will be used to implement
		2534	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2535	lot less memory), but otherwise doesn't affect guard operation much. It is
		2536	purely used for performance.
		2537
		2538	=item L<JSON> and L<JSON::XS>
		2539
		2540	One of these modules is required when you want to read or write JSON data
		2541	via L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2542	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2543
		2544	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2545	installed.
		2546
		2547	=item L<Net::SSLeay>
		2548
		2549	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2550	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2551	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2552
		2553	=item L<Time::HiRes>
		2554
		2555	This module is part of perl since release 5.008. It will be used when the
		2556	chosen event library does not come with a timing source on it's own. The
		2557	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2558	try to use a monotonic clock for timing stability.
		2559
		2560	=back
		2561
1794		2562
1795	=head1 FORK	2563	=head1 FORK
1796		2564
1797	Most event libraries are not fork-safe. The ones who are usually are	2565	Most event libraries are not fork-safe. The ones who are usually are
1798	because they rely on inefficient but fork-safe C<select> or C<poll>	2566	because they rely on inefficient but fork-safe C<select> or C<poll> calls
1799	calls. Only L<EV> is fully fork-aware.	2567	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2568	are usually badly thought-out hacks that are incompatible with fork in
		2569	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2570	continue event-processing in both parent and child (or both, if you know
		2571	what you are doing).
		2572
		2573	This means that, in general, you cannot fork and do event processing in
		2574	the child if the event library was initialised before the fork (which
		2575	usually happens when the first AnyEvent watcher is created, or the library
		2576	is loaded).
1800		2577
1801	If you have to fork, you must either do so I<before> creating your first	2578	If you have to fork, you must either do so I<before> creating your first
1802	watcher OR you must not use AnyEvent at all in the child.	2579	watcher OR you must not use AnyEvent at all in the child OR you must do
		2580	something completely out of the scope of AnyEvent.
		2581
		2582	The problem of doing event processing in the parent I<and> the child
		2583	is much more complicated: even for backends that I<are> fork-aware or
		2584	fork-safe, their behaviour is not usually what you want: fork clones all
		2585	watchers, that means all timers, I/O watchers etc. are active in both
		2586	parent and child, which is almost never what you want. USing C<exec>
		2587	to start worker children from some kind of manage rprocess is usually
		2588	preferred, because it is much easier and cleaner, at the expense of having
		2589	to have another binary.
1803		2590
1804		2591
1805	=head1 SECURITY CONSIDERATIONS	2592	=head1 SECURITY CONSIDERATIONS
1806		2593
1807	AnyEvent can be forced to load any event model via	2594	AnyEvent can be forced to load any event model via
…		…
1819	use AnyEvent;	2606	use AnyEvent;
1820		2607
1821	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2608	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1822	be used to probe what backend is used and gain other information (which is	2609	be used to probe what backend is used and gain other information (which is
1823	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2610	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1824	$ENV{PERL_ANYEGENT_STRICT}.	2611	$ENV{PERL_ANYEVENT_STRICT}.
		2612
		2613	Note that AnyEvent will remove I<all> environment variables starting with
		2614	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2615	enabled.
1825		2616
1826		2617
1827	=head1 BUGS	2618	=head1 BUGS
1828		2619
1829	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2620	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1830	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2621	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1831	and check wether the leaks still show up. (Perl 5.10.0 has other annoying	2622	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1832	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as	2623	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1833	pronounced).	2624	pronounced).
1834		2625
1835		2626
1836	=head1 SEE ALSO	2627	=head1 SEE ALSO
1837		2628
…		…
1841	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2632	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1842		2633
1843	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2634	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1844	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2635	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1845	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2636	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1846	L<AnyEvent::Impl::POE>.	2637	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1847		2638
1848	Non-blocking file handles, sockets, TCP clients and	2639	Non-blocking file handles, sockets, TCP clients and
1849	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2640	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1850		2641
1851	Asynchronous DNS: L<AnyEvent::DNS>.	2642	Asynchronous DNS: L<AnyEvent::DNS>.
1852		2643
1853	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2644	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2645	L<Coro::Event>,
1854		2646
1855	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2647	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2648	L<AnyEvent::HTTP>.
1856		2649
1857		2650
1858	=head1 AUTHOR	2651	=head1 AUTHOR
1859		2652
1860	Marc Lehmann <schmorp@schmorp.de>	2653	Marc Lehmann <schmorp@schmorp.de>

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