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Revision 1.180 by root, Sat Sep 6 07:00:45 2008 UTC vs.
Revision 1.305 by root, Sun Dec 13 05:13:15 2009 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 trigger as often	452	using C<0> watches for any child process exit, on others this will
346	as status change for the child are received. This works by installing a	453	croak). The watcher will be triggered only when the child process has
347	signal handler for C<SIGCHLD>. The callback will be called with the pid	454	finished and an exit status is available, not on any trace events
348	and exit status (as returned by waitpid), so unlike other watcher types,	455	(stopped/continued).
349	you I<can> rely on child watcher callback arguments.	456
		457	The callback will be called with the pid and exit status (as returned by
		458	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		459	callback arguments.
		460
		461	This watcher type works by installing a signal handler for C<SIGCHLD>,
		462	and since it cannot be shared, nothing else should use SIGCHLD or reap
		463	random child processes (waiting for specific child processes, e.g. inside
		464	C<system>, is just fine).
350		465
351	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
352	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
353	have exited already (and no SIGCHLD will be sent anymore).	468	have exited already (and no SIGCHLD will be sent anymore).
354		469
355	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
356	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
357	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.
358		476
359	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
360	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
361	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.
362		485
363	Example: fork a process and wait for it	486	Example: fork a process and wait for it
364		487
365	my $done = AnyEvent->condvar;	488	my $done = AnyEvent->condvar;
366		489
…		…
376	);	499	);
377		500
378	# do something else, then wait for process exit	501	# do something else, then wait for process exit
379	$done->recv;	502	$done->recv;
380		503
		504	=head2 IDLE WATCHERS
		505
		506	$w = AnyEvent->idle (cb => <callback>);
		507
		508	Sometimes there is a need to do something, but it is not so important
		509	to do it instantly, but only when there is nothing better to do. This
		510	"nothing better to do" is usually defined to be "no other events need
		511	attention by the event loop".
		512
		513	Idle watchers ideally get invoked when the event loop has nothing
		514	better to do, just before it would block the process to wait for new
		515	events. Instead of blocking, the idle watcher is invoked.
		516
		517	Most event loops unfortunately do not really support idle watchers (only
		518	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		519	will simply call the callback "from time to time".
		520
		521	Example: read lines from STDIN, but only process them when the
		522	program is otherwise idle:
		523
		524	my @lines; # read data
		525	my $idle_w;
		526	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		527	push @lines, scalar <STDIN>;
		528
		529	# start an idle watcher, if not already done
		530	$idle_w ||= AnyEvent->idle (cb => sub {
		531	# handle only one line, when there are lines left
		532	if (my $line = shift @lines) {
		533	print "handled when idle: $line";
		534	} else {
		535	# otherwise disable the idle watcher again
		536	undef $idle_w;
		537	}
		538	});
		539	});
		540
381	=head2 CONDITION VARIABLES	541	=head2 CONDITION VARIABLES
		542
		543	$cv = AnyEvent->condvar;
		544
		545	$cv->send (<list>);
		546	my @res = $cv->recv;
382		547
383	If you are familiar with some event loops you will know that all of them	548	If you are familiar with some event loops you will know that all of them
384	require you to run some blocking "loop", "run" or similar function that	549	require you to run some blocking "loop", "run" or similar function that
385	will actively watch for new events and call your callbacks.	550	will actively watch for new events and call your callbacks.
386		551
387	AnyEvent is different, it expects somebody else to run the event loop and	552	AnyEvent is slightly different: it expects somebody else to run the event
388	will only block when necessary (usually when told by the user).	553	loop and will only block when necessary (usually when told by the user).
389		554
390	The instrument to do that is called a "condition variable", so called	555	The instrument to do that is called a "condition variable", so called
391	because they represent a condition that must become true.	556	because they represent a condition that must become true.
392		557
		558	Now is probably a good time to look at the examples further below.
		559
393	Condition variables can be created by calling the C<< AnyEvent->condvar	560	Condition variables can be created by calling the C<< AnyEvent->condvar
394	>> method, usually without arguments. The only argument pair allowed is	561	>> method, usually without arguments. The only argument pair allowed is
395
396	C<cb>, which specifies a callback to be called when the condition variable	562	C<cb>, which specifies a callback to be called when the condition variable
397	becomes true, with the condition variable as the first argument (but not	563	becomes true, with the condition variable as the first argument (but not
398	the results).	564	the results).
399		565
400	After creation, the condition variable is "false" until it becomes "true"	566	After creation, the condition variable is "false" until it becomes "true"
…		…
405	Condition variables are similar to callbacks, except that you can	571	Condition variables are similar to callbacks, except that you can
406	optionally wait for them. They can also be called merge points - points	572	optionally wait for them. They can also be called merge points - points
407	in time where multiple outstanding events have been processed. And yet	573	in time where multiple outstanding events have been processed. And yet
408	another way to call them is transactions - each condition variable can be	574	another way to call them is transactions - each condition variable can be
409	used to represent a transaction, which finishes at some point and delivers	575	used to represent a transaction, which finishes at some point and delivers
410	a result.	576	a result. And yet some people know them as "futures" - a promise to
		577	compute/deliver something that you can wait for.
411		578
412	Condition variables are very useful to signal that something has finished,	579	Condition variables are very useful to signal that something has finished,
413	for example, if you write a module that does asynchronous http requests,	580	for example, if you write a module that does asynchronous http requests,
414	then a condition variable would be the ideal candidate to signal the	581	then a condition variable would be the ideal candidate to signal the
415	availability of results. The user can either act when the callback is	582	availability of results. The user can either act when the callback is
…		…
449	after => 1,	616	after => 1,
450	cb => sub { $result_ready->send },	617	cb => sub { $result_ready->send },
451	);	618	);
452		619
453	# this "blocks" (while handling events) till the callback	620	# this "blocks" (while handling events) till the callback
454	# calls send	621	# calls ->send
455	$result_ready->recv;	622	$result_ready->recv;
456		623
457	Example: wait for a timer, but take advantage of the fact that	624	Example: wait for a timer, but take advantage of the fact that condition
458	condition variables are also code references.	625	variables are also callable directly.
459		626
460	my $done = AnyEvent->condvar;	627	my $done = AnyEvent->condvar;
461	my $delay = AnyEvent->timer (after => 5, cb => $done);	628	my $delay = AnyEvent->timer (after => 5, cb => $done);
462	$done->recv;	629	$done->recv;
463		630
…		…
469		636
470	...	637	...
471		638
472	my @info = $couchdb->info->recv;	639	my @info = $couchdb->info->recv;
473		640
474	And this is how you would just ste a callback to be called whenever the	641	And this is how you would just set a callback to be called whenever the
475	results are available:	642	results are available:
476		643
477	$couchdb->info->cb (sub {	644	$couchdb->info->cb (sub {
478	my @info = $_[0]->recv;	645	my @info = $_[0]->recv;
479	});	646	});
…		…
497	immediately from within send.	664	immediately from within send.
498		665
499	Any arguments passed to the C<send> call will be returned by all	666	Any arguments passed to the C<send> call will be returned by all
500	future C<< ->recv >> calls.	667	future C<< ->recv >> calls.
501		668
502	Condition variables are overloaded so one can call them directly	669	Condition variables are overloaded so one can call them directly (as if
503	(as a code reference). Calling them directly is the same as calling	670	they were a code reference). Calling them directly is the same as calling
504	C<send>. Note, however, that many C-based event loops do not handle	671	C<send>.
505	overloading, so as tempting as it may be, passing a condition variable
506	instead of a callback does not work. Both the pure perl and EV loops
507	support overloading, however, as well as all functions that use perl to
508	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
509	example).
510		672
511	=item $cv->croak ($error)	673	=item $cv->croak ($error)
512		674
513	Similar to send, but causes all call's to C<< ->recv >> to invoke	675	Similar to send, but causes all call's to C<< ->recv >> to invoke
514	C<Carp::croak> with the given error message/object/scalar.	676	C<Carp::croak> with the given error message/object/scalar.
515		677
516	This can be used to signal any errors to the condition variable	678	This can be used to signal any errors to the condition variable
517	user/consumer.	679	user/consumer. Doing it this way instead of calling C<croak> directly
		680	delays the error detetcion, but has the overwhelmign advantage that it
		681	diagnoses the error at the place where the result is expected, and not
		682	deep in some event clalback without connection to the actual code causing
		683	the problem.
518		684
519	=item $cv->begin ([group callback])	685	=item $cv->begin ([group callback])
520		686
521	=item $cv->end	687	=item $cv->end
522
523	These two methods are EXPERIMENTAL and MIGHT CHANGE.
524		688
525	These two methods can be used to combine many transactions/events into	689	These two methods can be used to combine many transactions/events into
526	one. For example, a function that pings many hosts in parallel might want	690	one. For example, a function that pings many hosts in parallel might want
527	to use a condition variable for the whole process.	691	to use a condition variable for the whole process.
528		692
529	Every call to C<< ->begin >> will increment a counter, and every call to	693	Every call to C<< ->begin >> will increment a counter, and every call to
530	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	694	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
531	>>, the (last) callback passed to C<begin> will be executed. That callback	695	>>, the (last) callback passed to C<begin> will be executed, passing the
532	is I<supposed> to call C<< ->send >>, but that is not required. If no	696	condvar as first argument. That callback is I<supposed> to call C<< ->send
533	callback was set, C<send> will be called without any arguments.	697	>>, but that is not required. If no group callback was set, C<send> will
		698	be called without any arguments.
534		699
535	Let's clarify this with the ping example:	700	You can think of C<< $cv->send >> giving you an OR condition (one call
		701	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		702	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		703
		704	Let's start with a simple example: you have two I/O watchers (for example,
		705	STDOUT and STDERR for a program), and you want to wait for both streams to
		706	close before activating a condvar:
536		707
537	my $cv = AnyEvent->condvar;	708	my $cv = AnyEvent->condvar;
538		709
		710	$cv->begin; # first watcher
		711	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		712	defined sysread $fh1, my $buf, 4096
		713	or $cv->end;
		714	});
		715
		716	$cv->begin; # second watcher
		717	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		718	defined sysread $fh2, my $buf, 4096
		719	or $cv->end;
		720	});
		721
		722	$cv->recv;
		723
		724	This works because for every event source (EOF on file handle), there is
		725	one call to C<begin>, so the condvar waits for all calls to C<end> before
		726	sending.
		727
		728	The ping example mentioned above is slightly more complicated, as the
		729	there are results to be passwd back, and the number of tasks that are
		730	begung can potentially be zero:
		731
		732	my $cv = AnyEvent->condvar;
		733
539	my %result;	734	my %result;
540	$cv->begin (sub { $cv->send (\%result) });	735	$cv->begin (sub { shift->send (\%result) });
541		736
542	for my $host (@list_of_hosts) {	737	for my $host (@list_of_hosts) {
543	$cv->begin;	738	$cv->begin;
544	ping_host_then_call_callback $host, sub {	739	ping_host_then_call_callback $host, sub {
545	$result{$host} = ...;	740	$result{$host} = ...;
…		…
560	loop, which serves two important purposes: first, it sets the callback	755	loop, which serves two important purposes: first, it sets the callback
561	to be called once the counter reaches C<0>, and second, it ensures that	756	to be called once the counter reaches C<0>, and second, it ensures that
562	C<send> is called even when C<no> hosts are being pinged (the loop	757	C<send> is called even when C<no> hosts are being pinged (the loop
563	doesn't execute once).	758	doesn't execute once).
564		759
565	This is the general pattern when you "fan out" into multiple subrequests:	760	This is the general pattern when you "fan out" into multiple (but
566	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	761	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
567	is called at least once, and then, for each subrequest you start, call	762	the callback and ensure C<end> is called at least once, and then, for each
568	C<begin> and for each subrequest you finish, call C<end>.	763	subrequest you start, call C<begin> and for each subrequest you finish,
		764	call C<end>.
569		765
570	=back	766	=back
571		767
572	=head3 METHODS FOR CONSUMERS	768	=head3 METHODS FOR CONSUMERS
573		769
…		…
589	function will call C<croak>.	785	function will call C<croak>.
590		786
591	In list context, all parameters passed to C<send> will be returned,	787	In list context, all parameters passed to C<send> will be returned,
592	in scalar context only the first one will be returned.	788	in scalar context only the first one will be returned.
593		789
		790	Note that doing a blocking wait in a callback is not supported by any
		791	event loop, that is, recursive invocation of a blocking C<< ->recv
		792	>> is not allowed, and the C<recv> call will C<croak> if such a
		793	condition is detected. This condition can be slightly loosened by using
		794	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		795	any thread that doesn't run the event loop itself.
		796
594	Not all event models support a blocking wait - some die in that case	797	Not all event models support a blocking wait - some die in that case
595	(programs might want to do that to stay interactive), so I<if you are	798	(programs might want to do that to stay interactive), so I<if you are
596	using this from a module, never require a blocking wait>, but let the	799	using this from a module, never require a blocking wait>. Instead, let the
597	caller decide whether the call will block or not (for example, by coupling	800	caller decide whether the call will block or not (for example, by coupling
598	condition variables with some kind of request results and supporting	801	condition variables with some kind of request results and supporting
599	callbacks so the caller knows that getting the result will not block,	802	callbacks so the caller knows that getting the result will not block,
600	while still supporting blocking waits if the caller so desires).	803	while still supporting blocking waits if the caller so desires).
601		804
602	Another reason I<never> to C<< ->recv >> in a module is that you cannot
603	sensibly have two C<< ->recv >>'s in parallel, as that would require
604	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
605	can supply.
606
607	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
608	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
609	versions and also integrates coroutines into AnyEvent, making blocking
610	C<< ->recv >> calls perfectly safe as long as they are done from another
611	coroutine (one that doesn't run the event loop).
612
613	You can ensure that C<< -recv >> never blocks by setting a callback and	805	You can ensure that C<< -recv >> never blocks by setting a callback and
614	only calling C<< ->recv >> from within that callback (or at a later	806	only calling C<< ->recv >> from within that callback (or at a later
615	time). This will work even when the event loop does not support blocking	807	time). This will work even when the event loop does not support blocking
616	waits otherwise.	808	waits otherwise.
617		809
…		…
623	=item $cb = $cv->cb ($cb->($cv))	815	=item $cb = $cv->cb ($cb->($cv))
624		816
625	This is a mutator function that returns the callback set and optionally	817	This is a mutator function that returns the callback set and optionally
626	replaces it before doing so.	818	replaces it before doing so.
627		819
628	The callback will be called when the condition becomes "true", i.e. when	820	The callback will be called when the condition becomes (or already was)
629	C<send> or C<croak> are called, with the only argument being the condition	821	"true", i.e. when C<send> or C<croak> are called (or were called), with
630	variable itself. Calling C<recv> inside the callback or at any later time	822	the only argument being the condition variable itself. Calling C<recv>
631	is guaranteed not to block.	823	inside the callback or at any later time is guaranteed not to block.
632		824
633	=back	825	=back
634		826
		827	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		828
		829	The available backend classes are (every class has its own manpage):
		830
		831	=over 4
		832
		833	=item Backends that are autoprobed when no other event loop can be found.
		834
		835	EV is the preferred backend when no other event loop seems to be in
		836	use. If EV is not installed, then AnyEvent will fall back to its own
		837	pure-perl implementation, which is available everywhere as it comes with
		838	AnyEvent itself.
		839
		840	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		841	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		842
		843	=item Backends that are transparently being picked up when they are used.
		844
		845	These will be used when they are currently loaded when the first watcher
		846	is created, in which case it is assumed that the application is using
		847	them. This means that AnyEvent will automatically pick the right backend
		848	when the main program loads an event module before anything starts to
		849	create watchers. Nothing special needs to be done by the main program.
		850
		851	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		852	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		853	AnyEvent::Impl::Tk based on Tk, very broken.
		854	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		855	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		856	AnyEvent::Impl::Irssi used when running within irssi.
		857
		858	=item Backends with special needs.
		859
		860	Qt requires the Qt::Application to be instantiated first, but will
		861	otherwise be picked up automatically. As long as the main program
		862	instantiates the application before any AnyEvent watchers are created,
		863	everything should just work.
		864
		865	AnyEvent::Impl::Qt based on Qt.
		866
		867	Support for IO::Async can only be partial, as it is too broken and
		868	architecturally limited to even support the AnyEvent API. It also
		869	is the only event loop that needs the loop to be set explicitly, so
		870	it can only be used by a main program knowing about AnyEvent. See
		871	L<AnyEvent::Impl::Async> for the gory details.
		872
		873	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		874
		875	=item Event loops that are indirectly supported via other backends.
		876
		877	Some event loops can be supported via other modules:
		878
		879	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		880
		881	B<WxWidgets> has no support for watching file handles. However, you can
		882	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		883	polls 20 times per second, which was considered to be too horrible to even
		884	consider for AnyEvent.
		885
		886	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		887	backend, so it can be supported through POE.
		888
		889	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		890	load L<POE> when detecting them, in the hope that POE will pick them up,
		891	in which case everything will be automatic.
		892
		893	=back
		894
635	=head1 GLOBAL VARIABLES AND FUNCTIONS	895	=head1 GLOBAL VARIABLES AND FUNCTIONS
636		896
		897	These are not normally required to use AnyEvent, but can be useful to
		898	write AnyEvent extension modules.
		899
637	=over 4	900	=over 4
638		901
639	=item $AnyEvent::MODEL	902	=item $AnyEvent::MODEL
640		903
641	Contains C<undef> until the first watcher is being created. Then it	904	Contains C<undef> until the first watcher is being created, before the
		905	backend has been autodetected.
		906
642	contains the event model that is being used, which is the name of the	907	Afterwards it contains the event model that is being used, which is the
643	Perl class implementing the model. This class is usually one of the	908	name of the Perl class implementing the model. This class is usually one
644	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	909	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
645	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	910	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
646		911	will be C<urxvt::anyevent>).
647	The known classes so far are:
648
649	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
650	AnyEvent::Impl::Event based on Event, second best choice.
651	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
652	AnyEvent::Impl::Glib based on Glib, third-best choice.
653	AnyEvent::Impl::Tk based on Tk, very bad choice.
654	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
655	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
656	AnyEvent::Impl::POE based on POE, not generic enough for full support.
657
658	There is no support for WxWidgets, as WxWidgets has no support for
659	watching file handles. However, you can use WxWidgets through the
660	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
661	second, which was considered to be too horrible to even consider for
662	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
663	it's adaptor.
664
665	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
666	autodetecting them.
667		912
668	=item AnyEvent::detect	913	=item AnyEvent::detect
669		914
670	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	915	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
671	if necessary. You should only call this function right before you would	916	if necessary. You should only call this function right before you would
672	have created an AnyEvent watcher anyway, that is, as late as possible at	917	have created an AnyEvent watcher anyway, that is, as late as possible at
673	runtime.	918	runtime, and not e.g. while initialising of your module.
		919
		920	If you need to do some initialisation before AnyEvent watchers are
		921	created, use C<post_detect>.
674		922
675	=item $guard = AnyEvent::post_detect { BLOCK }	923	=item $guard = AnyEvent::post_detect { BLOCK }
676		924
677	Arranges for the code block to be executed as soon as the event model is	925	Arranges for the code block to be executed as soon as the event model is
678	autodetected (or immediately if this has already happened).	926	autodetected (or immediately if this has already happened).
679		927
		928	The block will be executed I<after> the actual backend has been detected
		929	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		930	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		931	other initialisations - see the sources of L<AnyEvent::Strict> or
		932	L<AnyEvent::AIO> to see how this is used.
		933
		934	The most common usage is to create some global watchers, without forcing
		935	event module detection too early, for example, L<AnyEvent::AIO> creates
		936	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		937	avoid autodetecting the event module at load time.
		938
680	If called in scalar or list context, then it creates and returns an object	939	If called in scalar or list context, then it creates and returns an object
681	that automatically removes the callback again when it is destroyed. See	940	that automatically removes the callback again when it is destroyed (or
		941	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
682	L<Coro::BDB> for a case where this is useful.	942	a case where this is useful.
		943
		944	Example: Create a watcher for the IO::AIO module and store it in
		945	C<$WATCHER>. Only do so after the event loop is initialised, though.
		946
		947	our WATCHER;
		948
		949	my $guard = AnyEvent::post_detect {
		950	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		951	};
		952
		953	# the ||= is important in case post_detect immediately runs the block,
		954	# as to not clobber the newly-created watcher. assigning both watcher and
		955	# post_detect guard to the same variable has the advantage of users being
		956	# able to just C<undef $WATCHER> if the watcher causes them grief.
		957
		958	$WATCHER ||= $guard;
683		959
684	=item @AnyEvent::post_detect	960	=item @AnyEvent::post_detect
685		961
686	If there are any code references in this array (you can C<push> to it	962	If there are any code references in this array (you can C<push> to it
687	before or after loading AnyEvent), then they will called directly after	963	before or after loading AnyEvent), then they will called directly after
688	the event loop has been chosen.	964	the event loop has been chosen.
689		965
690	You should check C<$AnyEvent::MODEL> before adding to this array, though:	966	You should check C<$AnyEvent::MODEL> before adding to this array, though:
691	if it contains a true value then the event loop has already been detected,	967	if it is defined then the event loop has already been detected, and the
692	and the array will be ignored.	968	array will be ignored.
693		969
694	Best use C<AnyEvent::post_detect { BLOCK }> instead.	970	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		971	it, as it takes care of these details.
		972
		973	This variable is mainly useful for modules that can do something useful
		974	when AnyEvent is used and thus want to know when it is initialised, but do
		975	not need to even load it by default. This array provides the means to hook
		976	into AnyEvent passively, without loading it.
		977
		978	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		979	together, you could put this into Coro (this is the actual code used by
		980	Coro to accomplish this):
		981
		982	if (defined $AnyEvent::MODEL) {
		983	# AnyEvent already initialised, so load Coro::AnyEvent
		984	require Coro::AnyEvent;
		985	} else {
		986	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		987	# as soon as it is
		988	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		989	}
695		990
696	=back	991	=back
697		992
698	=head1 WHAT TO DO IN A MODULE	993	=head1 WHAT TO DO IN A MODULE
699		994
…		…
754		1049
755		1050
756	=head1 OTHER MODULES	1051	=head1 OTHER MODULES
757		1052
758	The following is a non-exhaustive list of additional modules that use	1053	The following is a non-exhaustive list of additional modules that use
759	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1054	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
760	in the same program. Some of the modules come with AnyEvent, some are	1055	modules and other event loops in the same program. Some of the modules
761	available via CPAN.	1056	come with AnyEvent, most are available via CPAN.
762		1057
763	=over 4	1058	=over 4
764		1059
765	=item L<AnyEvent::Util>	1060	=item L<AnyEvent::Util>
766		1061
…		…
775		1070
776	=item L<AnyEvent::Handle>	1071	=item L<AnyEvent::Handle>
777		1072
778	Provide read and write buffers, manages watchers for reads and writes,	1073	Provide read and write buffers, manages watchers for reads and writes,
779	supports raw and formatted I/O, I/O queued and fully transparent and	1074	supports raw and formatted I/O, I/O queued and fully transparent and
780	non-blocking SSL/TLS.	1075	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
781		1076
782	=item L<AnyEvent::DNS>	1077	=item L<AnyEvent::DNS>
783		1078
784	Provides rich asynchronous DNS resolver capabilities.	1079	Provides rich asynchronous DNS resolver capabilities.
785		1080
…		…
813		1108
814	=item L<AnyEvent::GPSD>	1109	=item L<AnyEvent::GPSD>
815		1110
816	A non-blocking interface to gpsd, a daemon delivering GPS information.	1111	A non-blocking interface to gpsd, a daemon delivering GPS information.
817		1112
		1113	=item L<AnyEvent::IRC>
		1114
		1115	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1116
		1117	=item L<AnyEvent::XMPP>
		1118
		1119	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1120	Net::XMPP2>.
		1121
818	=item L<AnyEvent::IGS>	1122	=item L<AnyEvent::IGS>
819		1123
820	A non-blocking interface to the Internet Go Server protocol (used by	1124	A non-blocking interface to the Internet Go Server protocol (used by
821	L<App::IGS>).	1125	L<App::IGS>).
822		1126
823	=item L<Net::IRC3>
824
825	AnyEvent based IRC client module family.
826
827	=item L<Net::XMPP2>
828
829	AnyEvent based XMPP (Jabber protocol) module family.
830
831	=item L<Net::FCP>	1127	=item L<Net::FCP>
832		1128
833	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1129	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
834	of AnyEvent.	1130	of AnyEvent.
835		1131
…		…
839		1135
840	=item L<Coro>	1136	=item L<Coro>
841		1137
842	Has special support for AnyEvent via L<Coro::AnyEvent>.	1138	Has special support for AnyEvent via L<Coro::AnyEvent>.
843		1139
844	=item L<IO::Lambda>
845
846	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
847
848	=back	1140	=back
849		1141
850	=cut	1142	=cut
851		1143
852	package AnyEvent;	1144	package AnyEvent;
853		1145
854	no warnings;	1146	# basically a tuned-down version of common::sense
		1147	sub common_sense {
		1148	# from common:.sense 1.0
		1149	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
855	use strict qw(vars subs);	1150	# use strict vars subs
		1151	$^H |= 0x00000600;
		1152	}
856		1153
		1154	BEGIN { AnyEvent::common_sense }
		1155
857	use Carp;	1156	use Carp ();
858		1157
859	our $VERSION = 4.233;	1158	our $VERSION = '5.22';
860	our $MODEL;	1159	our $MODEL;
861		1160
862	our $AUTOLOAD;	1161	our $AUTOLOAD;
863	our @ISA;	1162	our @ISA;
864		1163
865	our @REGISTRY;	1164	our @REGISTRY;
866		1165
867	our $WIN32;	1166	our $VERBOSE;
868		1167
869	BEGIN {	1168	BEGIN {
870	my $win32 = ! ! ($^O =~ /mswin32/i);	1169	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
871	eval "sub WIN32(){ $win32 }";	1170	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
872	}
873		1171
		1172	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1173	if ${^TAINT};
		1174
874	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1175	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1176
		1177	}
		1178
		1179	our $MAX_SIGNAL_LATENCY = 10;
875		1180
876	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1181	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
877		1182
878	{	1183	{
879	my $idx;	1184	my $idx;
…		…
881	for reverse split /\s*,\s*/,	1186	for reverse split /\s*,\s*/,
882	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1187	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
883	}	1188	}
884		1189
885	my @models = (	1190	my @models = (
886	[EV:: => AnyEvent::Impl::EV::],	1191	[EV:: => AnyEvent::Impl::EV:: , 1],
887	[Event:: => AnyEvent::Impl::Event::],
888	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1192	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
889	# everything below here will not be autoprobed	1193	# everything below here will not (normally) be autoprobed
890	# as the pureperl backend should work everywhere	1194	# as the pureperl backend should work everywhere
891	# and is usually faster	1195	# and is usually faster
		1196	[Event:: => AnyEvent::Impl::Event::, 1],
		1197	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1198	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1199	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
892	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1200	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
893	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
894	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
895	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1201	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
896	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1202	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
897	[Wx:: => AnyEvent::Impl::POE::],	1203	[Wx:: => AnyEvent::Impl::POE::],
898	[Prima:: => AnyEvent::Impl::POE::],	1204	[Prima:: => AnyEvent::Impl::POE::],
		1205	# IO::Async is just too broken - we would need workarounds for its
		1206	# byzantine signal and broken child handling, among others.
		1207	# IO::Async is rather hard to detect, as it doesn't have any
		1208	# obvious default class.
		1209	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1210	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1211	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1212	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
899	);	1213	);
900		1214
901	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1215	our %method = map +($_ => 1),
		1216	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
902		1217
903	our @post_detect;	1218	our @post_detect;
904		1219
905	sub post_detect(&) {	1220	sub post_detect(&) {
906	my ($cb) = @_;	1221	my ($cb) = @_;
907		1222
908	if ($MODEL) {	1223	if ($MODEL) {
909	$cb->();	1224	$cb->();
910		1225
911	1	1226	undef
912	} else {	1227	} else {
913	push @post_detect, $cb;	1228	push @post_detect, $cb;
914		1229
915	defined wantarray	1230	defined wantarray
916	? bless \$cb, "AnyEvent::Util::PostDetect"	1231	? bless \$cb, "AnyEvent::Util::postdetect"
917	: ()	1232	: ()
918	}	1233	}
919	}	1234	}
920		1235
921	sub AnyEvent::Util::PostDetect::DESTROY {	1236	sub AnyEvent::Util::postdetect::DESTROY {
922	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1237	@post_detect = grep $_ != ${$_[0]}, @post_detect;
923	}	1238	}
924		1239
925	sub detect() {	1240	sub detect() {
926	unless ($MODEL) {	1241	unless ($MODEL) {
927	no strict 'refs';
928	local $SIG{__DIE__};	1242	local $SIG{__DIE__};
929		1243
930	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1244	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
931	my $model = "AnyEvent::Impl::$1";	1245	my $model = "AnyEvent::Impl::$1";
932	if (eval "require $model") {	1246	if (eval "require $model") {
933	$MODEL = $model;	1247	$MODEL = $model;
934	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1248	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
935	} else {	1249	} else {
936	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1250	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
937	}	1251	}
938	}	1252	}
939		1253
940	# check for already loaded models	1254	# check for already loaded models
941	unless ($MODEL) {	1255	unless ($MODEL) {
942	for (@REGISTRY, @models) {	1256	for (@REGISTRY, @models) {
943	my ($package, $model) = @$_;	1257	my ($package, $model) = @$_;
944	if (${"$package\::VERSION"} > 0) {	1258	if (${"$package\::VERSION"} > 0) {
945	if (eval "require $model") {	1259	if (eval "require $model") {
946	$MODEL = $model;	1260	$MODEL = $model;
947	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1261	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
948	last;	1262	last;
949	}	1263	}
950	}	1264	}
951	}	1265	}
952		1266
953	unless ($MODEL) {	1267	unless ($MODEL) {
954	# try to load a model	1268	# try to autoload a model
955
956	for (@REGISTRY, @models) {	1269	for (@REGISTRY, @models) {
957	my ($package, $model) = @$_;	1270	my ($package, $model, $autoload) = @$_;
		1271	if (
		1272	$autoload
958	if (eval "require $package"	1273	and eval "require $package"
959	and ${"$package\::VERSION"} > 0	1274	and ${"$package\::VERSION"} > 0
960	and eval "require $model") {	1275	and eval "require $model"
		1276	) {
961	$MODEL = $model;	1277	$MODEL = $model;
962	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1278	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
963	last;	1279	last;
964	}	1280	}
965	}	1281	}
966		1282
967	$MODEL	1283	$MODEL
968	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1284	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
969	}	1285	}
970	}	1286	}
971		1287
972	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1288	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
973		1289
…		…
983		1299
984	sub AUTOLOAD {	1300	sub AUTOLOAD {
985	(my $func = $AUTOLOAD) =~ s/.*://;	1301	(my $func = $AUTOLOAD) =~ s/.*://;
986		1302
987	$method{$func}	1303	$method{$func}
988	or croak "$func: not a valid method for AnyEvent objects";	1304	or Carp::croak "$func: not a valid method for AnyEvent objects";
989		1305
990	detect unless $MODEL;	1306	detect unless $MODEL;
991		1307
992	my $class = shift;	1308	my $class = shift;
993	$class->$func (@_);	1309	$class->$func (@_);
994	}	1310	}
995		1311
996	# utility function to dup a filehandle. this is used by many backends	1312	# utility function to dup a filehandle. this is used by many backends
997	# to support binding more than one watcher per filehandle (they usually	1313	# to support binding more than one watcher per filehandle (they usually
998	# allow only one watcher per fd, so we dup it to get a different one).	1314	# allow only one watcher per fd, so we dup it to get a different one).
999	sub _dupfh($$$$) {	1315	sub _dupfh($$;$$) {
1000	my ($poll, $fh, $r, $w) = @_;	1316	my ($poll, $fh, $r, $w) = @_;
1001		1317
1002	require Fcntl;
1003
1004	# cygwin requires the fh mode to be matching, unix doesn't	1318	# cygwin requires the fh mode to be matching, unix doesn't
1005	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1319	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1006	: $poll eq "w" ? ($w, ">")
1007	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1008		1320
1009	open my $fh2, "$mode&" . fileno $fh	1321	open my $fh2, $mode, $fh
1010	or die "cannot dup() filehandle: $!";	1322	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1011		1323
1012	# we assume CLOEXEC is already set by perl in all important cases	1324	# we assume CLOEXEC is already set by perl in all important cases
1013		1325
1014	($fh2, $rw)	1326	($fh2, $rw)
1015	}	1327	}
1016		1328
		1329	=head1 SIMPLIFIED AE API
		1330
		1331	Starting with version 5.0, AnyEvent officially supports a second, much
		1332	simpler, API that is designed to reduce the calling, typing and memory
		1333	overhead.
		1334
		1335	See the L<AE> manpage for details.
		1336
		1337	=cut
		1338
		1339	package AE;
		1340
		1341	our $VERSION = $AnyEvent::VERSION;
		1342
		1343	sub io($$$) {
		1344	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1345	}
		1346
		1347	sub timer($$$) {
		1348	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1349	}
		1350
		1351	sub signal($$) {
		1352	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1353	}
		1354
		1355	sub child($$) {
		1356	AnyEvent->child (pid => $_[0], cb => $_[1])
		1357	}
		1358
		1359	sub idle($) {
		1360	AnyEvent->idle (cb => $_[0])
		1361	}
		1362
		1363	sub cv(;&) {
		1364	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1365	}
		1366
		1367	sub now() {
		1368	AnyEvent->now
		1369	}
		1370
		1371	sub now_update() {
		1372	AnyEvent->now_update
		1373	}
		1374
		1375	sub time() {
		1376	AnyEvent->time
		1377	}
		1378
1017	package AnyEvent::Base;	1379	package AnyEvent::Base;
1018		1380
1019	# default implementation for now and time	1381	# default implementations for many methods
1020		1382
1021	BEGIN {	1383	sub _time() {
		1384	# probe for availability of Time::HiRes
1022	if (eval "use Time::HiRes (); time (); 1") {	1385	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1386	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1023	*_time = \&Time::HiRes::time;	1387	*_time = \&Time::HiRes::time;
1024	# if (eval "use POSIX (); (POSIX::times())...	1388	# if (eval "use POSIX (); (POSIX::times())...
1025	} else {	1389	} else {
		1390	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1026	*_time = \&CORE::time; # epic fail	1391	*_time = sub { time }; # epic fail
1027	}	1392	}
		1393
		1394	&_time
1028	}	1395	}
1029		1396
1030	sub time { _time }	1397	sub time { _time }
1031	sub now { _time }	1398	sub now { _time }
		1399	sub now_update { }
1032		1400
1033	# default implementation for ->condvar	1401	# default implementation for ->condvar
1034		1402
1035	sub condvar {	1403	sub condvar {
1036	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1404	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1037	}	1405	}
1038		1406
1039	# default implementation for ->signal	1407	# default implementation for ->signal
1040		1408
1041	our %SIG_CB;	1409	our $HAVE_ASYNC_INTERRUPT;
		1410
		1411	sub _have_async_interrupt() {
		1412	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1413	&& eval "use Async::Interrupt 1.02 (); 1")
		1414	unless defined $HAVE_ASYNC_INTERRUPT;
		1415
		1416	$HAVE_ASYNC_INTERRUPT
		1417	}
		1418
		1419	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1420	our (%SIG_ASY, %SIG_ASY_W);
		1421	our ($SIG_COUNT, $SIG_TW);
		1422
		1423	sub _signal_exec {
		1424	$HAVE_ASYNC_INTERRUPT
		1425	? $SIGPIPE_R->drain
		1426	: sysread $SIGPIPE_R, (my $dummy), 9;
		1427
		1428	while (%SIG_EV) {
		1429	for (keys %SIG_EV) {
		1430	delete $SIG_EV{$_};
		1431	$_->() for values %{ $SIG_CB{$_} || {} };
		1432	}
		1433	}
		1434	}
		1435
		1436	# install a dummy wakeup watcher to reduce signal catching latency
		1437	sub _sig_add() {
		1438	unless ($SIG_COUNT++) {
		1439	# try to align timer on a full-second boundary, if possible
		1440	my $NOW = AE::now;
		1441
		1442	$SIG_TW = AE::timer
		1443	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1444	$MAX_SIGNAL_LATENCY,
		1445	sub { } # just for the PERL_ASYNC_CHECK
		1446	;
		1447	}
		1448	}
		1449
		1450	sub _sig_del {
		1451	undef $SIG_TW
		1452	unless --$SIG_COUNT;
		1453	}
		1454
		1455	our $_sig_name_init; $_sig_name_init = sub {
		1456	eval q{ # poor man's autoloading
		1457	undef $_sig_name_init;
		1458
		1459	if (_have_async_interrupt) {
		1460	*sig2num = \&Async::Interrupt::sig2num;
		1461	*sig2name = \&Async::Interrupt::sig2name;
		1462	} else {
		1463	require Config;
		1464
		1465	my %signame2num;
		1466	@signame2num{ split ' ', $Config::Config{sig_name} }
		1467	= split ' ', $Config::Config{sig_num};
		1468
		1469	my @signum2name;
		1470	@signum2name[values %signame2num] = keys %signame2num;
		1471
		1472	*sig2num = sub($) {
		1473	$_[0] > 0 ? shift : $signame2num{+shift}
		1474	};
		1475	*sig2name = sub ($) {
		1476	$_[0] > 0 ? $signum2name[+shift] : shift
		1477	};
		1478	}
		1479	};
		1480	die if $@;
		1481	};
		1482
		1483	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1484	sub sig2name($) { &$_sig_name_init; &sig2name }
1042		1485
1043	sub signal {	1486	sub signal {
		1487	eval q{ # poor man's autoloading {}
		1488	# probe for availability of Async::Interrupt
		1489	if (_have_async_interrupt) {
		1490	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
		1491
		1492	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1493	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
		1494
		1495	} else {
		1496	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1497
		1498	require Fcntl;
		1499
		1500	if (AnyEvent::WIN32) {
		1501	require AnyEvent::Util;
		1502
		1503	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1504	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1505	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1506	} else {
		1507	pipe $SIGPIPE_R, $SIGPIPE_W;
		1508	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1509	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1510
		1511	# not strictly required, as $^F is normally 2, but let's make sure...
		1512	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1513	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1514	}
		1515
		1516	$SIGPIPE_R
		1517	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1518
		1519	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
		1520	}
		1521
		1522	*signal = sub {
1044	my (undef, %arg) = @_;	1523	my (undef, %arg) = @_;
1045		1524
1046	my $signal = uc $arg{signal}	1525	my $signal = uc $arg{signal}
1047	or Carp::croak "required option 'signal' is missing";	1526	or Carp::croak "required option 'signal' is missing";
1048		1527
		1528	if ($HAVE_ASYNC_INTERRUPT) {
		1529	# async::interrupt
		1530
		1531	$signal = sig2num $signal;
1049	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1532	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1533
		1534	$SIG_ASY{$signal} ||= new Async::Interrupt
		1535	cb => sub { undef $SIG_EV{$signal} },
		1536	signal => $signal,
		1537	pipe => [$SIGPIPE_R->filenos],
		1538	pipe_autodrain => 0,
		1539	;
		1540
		1541	} else {
		1542	# pure perl
		1543
		1544	# AE::Util has been loaded in signal
		1545	$signal = sig2name $signal;
		1546	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1547
1050	$SIG{$signal} ||= sub {	1548	$SIG{$signal} ||= sub {
1051	$_->() for values %{ $SIG_CB{$signal} || {} };	1549	local $!;
		1550	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1551	undef $SIG_EV{$signal};
		1552	};
		1553
		1554	# can't do signal processing without introducing races in pure perl,
		1555	# so limit the signal latency.
		1556	_sig_add;
		1557	}
		1558
		1559	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1560	};
		1561
		1562	*AnyEvent::Base::signal::DESTROY = sub {
		1563	my ($signal, $cb) = @{$_[0]};
		1564
		1565	_sig_del;
		1566
		1567	delete $SIG_CB{$signal}{$cb};
		1568
		1569	$HAVE_ASYNC_INTERRUPT
		1570	? delete $SIG_ASY{$signal}
		1571	: # delete doesn't work with older perls - they then
		1572	# print weird messages, or just unconditionally exit
		1573	# instead of getting the default action.
		1574	undef $SIG{$signal}
		1575	unless keys %{ $SIG_CB{$signal} };
		1576	};
1052	};	1577	};
1053		1578	die if $@;
1054	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1579	&signal
1055	}
1056
1057	sub AnyEvent::Base::Signal::DESTROY {
1058	my ($signal, $cb) = @{$_[0]};
1059
1060	delete $SIG_CB{$signal}{$cb};
1061
1062	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1063	}	1580	}
1064		1581
1065	# default implementation for ->child	1582	# default implementation for ->child
1066		1583
1067	our %PID_CB;	1584	our %PID_CB;
1068	our $CHLD_W;	1585	our $CHLD_W;
1069	our $CHLD_DELAY_W;	1586	our $CHLD_DELAY_W;
1070	our $PID_IDLE;
1071	our $WNOHANG;	1587	our $WNOHANG;
1072		1588
1073	sub _child_wait {	1589	sub _emit_childstatus($$) {
1074	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1590	my (undef, $rpid, $rstatus) = @_;
		1591
		1592	$_->($rpid, $rstatus)
1075	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1593	for values %{ $PID_CB{$rpid} || {} },
1076	(values %{ $PID_CB{0} || {} });	1594	values %{ $PID_CB{0} || {} };
1077	}
1078
1079	undef $PID_IDLE;
1080	}	1595	}
1081		1596
1082	sub _sigchld {	1597	sub _sigchld {
1083	# make sure we deliver these changes "synchronous" with the event loop.	1598	my $pid;
1084	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {	1599
1085	undef $CHLD_DELAY_W;	1600	AnyEvent->_emit_childstatus ($pid, $?)
1086	&_child_wait;	1601	while ($pid = waitpid -1, $WNOHANG) > 0;
1087	});
1088	}	1602	}
1089		1603
1090	sub child {	1604	sub child {
1091	my (undef, %arg) = @_;	1605	my (undef, %arg) = @_;
1092		1606
1093	defined (my $pid = $arg{pid} + 0)	1607	defined (my $pid = $arg{pid} + 0)
1094	or Carp::croak "required option 'pid' is missing";	1608	or Carp::croak "required option 'pid' is missing";
1095		1609
1096	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1610	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1097		1611
1098	unless ($WNOHANG) {	1612	# WNOHANG is almost cetrainly 1 everywhere
		1613	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1614	? 1
1099	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1615	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1100	}
1101		1616
1102	unless ($CHLD_W) {	1617	unless ($CHLD_W) {
1103	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1618	$CHLD_W = AE::signal CHLD => \&_sigchld;
1104	# child could be a zombie already, so make at least one round	1619	# child could be a zombie already, so make at least one round
1105	&_sigchld;	1620	&_sigchld;
1106	}	1621	}
1107		1622
1108	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1623	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1109	}	1624	}
1110		1625
1111	sub AnyEvent::Base::Child::DESTROY {	1626	sub AnyEvent::Base::child::DESTROY {
1112	my ($pid, $cb) = @{$_[0]};	1627	my ($pid, $cb) = @{$_[0]};
1113		1628
1114	delete $PID_CB{$pid}{$cb};	1629	delete $PID_CB{$pid}{$cb};
1115	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1630	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1116		1631
1117	undef $CHLD_W unless keys %PID_CB;	1632	undef $CHLD_W unless keys %PID_CB;
1118	}	1633	}
1119		1634
		1635	# idle emulation is done by simply using a timer, regardless
		1636	# of whether the process is idle or not, and not letting
		1637	# the callback use more than 50% of the time.
		1638	sub idle {
		1639	my (undef, %arg) = @_;
		1640
		1641	my ($cb, $w, $rcb) = $arg{cb};
		1642
		1643	$rcb = sub {
		1644	if ($cb) {
		1645	$w = _time;
		1646	&$cb;
		1647	$w = _time - $w;
		1648
		1649	# never use more then 50% of the time for the idle watcher,
		1650	# within some limits
		1651	$w = 0.0001 if $w < 0.0001;
		1652	$w = 5 if $w > 5;
		1653
		1654	$w = AE::timer $w, 0, $rcb;
		1655	} else {
		1656	# clean up...
		1657	undef $w;
		1658	undef $rcb;
		1659	}
		1660	};
		1661
		1662	$w = AE::timer 0.05, 0, $rcb;
		1663
		1664	bless \\$cb, "AnyEvent::Base::idle"
		1665	}
		1666
		1667	sub AnyEvent::Base::idle::DESTROY {
		1668	undef $${$_[0]};
		1669	}
		1670
1120	package AnyEvent::CondVar;	1671	package AnyEvent::CondVar;
1121		1672
1122	our @ISA = AnyEvent::CondVar::Base::;	1673	our @ISA = AnyEvent::CondVar::Base::;
1123		1674
1124	package AnyEvent::CondVar::Base;	1675	package AnyEvent::CondVar::Base;
1125		1676
1126	use overload	1677	#use overload
1127	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1678	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1128	fallback => 1;	1679	# fallback => 1;
		1680
		1681	# save 300+ kilobytes by dirtily hardcoding overloading
		1682	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1683	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1684	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1685	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1686
		1687	our $WAITING;
1129		1688
1130	sub _send {	1689	sub _send {
1131	# nop	1690	# nop
1132	}	1691	}
1133		1692
…		…
1146	sub ready {	1705	sub ready {
1147	$_[0]{_ae_sent}	1706	$_[0]{_ae_sent}
1148	}	1707	}
1149		1708
1150	sub _wait {	1709	sub _wait {
		1710	$WAITING
		1711	and !$_[0]{_ae_sent}
		1712	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1713
		1714	local $WAITING = 1;
1151	AnyEvent->one_event while !$_[0]{_ae_sent};	1715	AnyEvent->one_event while !$_[0]{_ae_sent};
1152	}	1716	}
1153		1717
1154	sub recv {	1718	sub recv {
1155	$_[0]->_wait;	1719	$_[0]->_wait;
…		…
1157	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1721	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1158	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1722	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1159	}	1723	}
1160		1724
1161	sub cb {	1725	sub cb {
1162	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1726	my $cv = shift;
		1727
		1728	@_
		1729	and $cv->{_ae_cb} = shift
		1730	and $cv->{_ae_sent}
		1731	and (delete $cv->{_ae_cb})->($cv);
		1732
1163	$_[0]{_ae_cb}	1733	$cv->{_ae_cb}
1164	}	1734	}
1165		1735
1166	sub begin {	1736	sub begin {
1167	++$_[0]{_ae_counter};	1737	++$_[0]{_ae_counter};
1168	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1738	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1196	so on.	1766	so on.
1197		1767
1198	=head1 ENVIRONMENT VARIABLES	1768	=head1 ENVIRONMENT VARIABLES
1199		1769
1200	The following environment variables are used by this module or its	1770	The following environment variables are used by this module or its
1201	submodules:	1771	submodules.
		1772
		1773	Note that AnyEvent will remove I<all> environment variables starting with
		1774	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1775	enabled.
1202		1776
1203	=over 4	1777	=over 4
1204		1778
1205	=item C<PERL_ANYEVENT_VERBOSE>	1779	=item C<PERL_ANYEVENT_VERBOSE>
1206		1780
…		…
1213	C<PERL_ANYEVENT_MODEL>.	1787	C<PERL_ANYEVENT_MODEL>.
1214		1788
1215	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1789	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1216	model it chooses.	1790	model it chooses.
1217		1791
		1792	When set to C<8> or higher, then AnyEvent will report extra information on
		1793	which optional modules it loads and how it implements certain features.
		1794
1218	=item C<PERL_ANYEVENT_STRICT>	1795	=item C<PERL_ANYEVENT_STRICT>
1219		1796
1220	AnyEvent does not do much argument checking by default, as thorough	1797	AnyEvent does not do much argument checking by default, as thorough
1221	argument checking is very costly. Setting this variable to a true value	1798	argument checking is very costly. Setting this variable to a true value
1222	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1799	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1223	check the arguments passed to most method calls. If it finds any problems	1800	check the arguments passed to most method calls. If it finds any problems,
1224	it will croak.	1801	it will croak.
1225		1802
1226	In other words, enables "strict" mode.	1803	In other words, enables "strict" mode.
1227		1804
1228	Unlike C<use strict>, it is definitely recommended ot keep it off in	1805	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1229	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1806	>>, it is definitely recommended to keep it off in production. Keeping
1230	developing programs can be very useful, however.	1807	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1808	can be very useful, however.
1231		1809
1232	=item C<PERL_ANYEVENT_MODEL>	1810	=item C<PERL_ANYEVENT_MODEL>
1233		1811
1234	This can be used to specify the event model to be used by AnyEvent, before	1812	This can be used to specify the event model to be used by AnyEvent, before
1235	auto detection and -probing kicks in. It must be a string consisting	1813	auto detection and -probing kicks in. It must be a string consisting
…		…
1256	used, and preference will be given to protocols mentioned earlier in the	1834	used, and preference will be given to protocols mentioned earlier in the
1257	list.	1835	list.
1258		1836
1259	This variable can effectively be used for denial-of-service attacks	1837	This variable can effectively be used for denial-of-service attacks
1260	against local programs (e.g. when setuid), although the impact is likely	1838	against local programs (e.g. when setuid), although the impact is likely
1261	small, as the program has to handle connection errors already-	1839	small, as the program has to handle conenction and other failures anyways.
1262		1840
1263	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,	1841	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1264	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>	1842	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1265	- only support IPv4, never try to resolve or contact IPv6	1843	- only support IPv4, never try to resolve or contact IPv6
1266	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or	1844	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
…		…
1278		1856
1279	=item C<PERL_ANYEVENT_MAX_FORKS>	1857	=item C<PERL_ANYEVENT_MAX_FORKS>
1280		1858
1281	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1859	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1282	will create in parallel.	1860	will create in parallel.
		1861
		1862	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1863
		1864	The default value for the C<max_outstanding> parameter for the default DNS
		1865	resolver - this is the maximum number of parallel DNS requests that are
		1866	sent to the DNS server.
		1867
		1868	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1869
		1870	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1871	configuration) in the default resolver. When set to the empty string, no
		1872	default config will be used.
		1873
		1874	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1875
		1876	When neither C<ca_file> nor C<ca_path> was specified during
		1877	L<AnyEvent::TLS> context creation, and either of these environment
		1878	variables exist, they will be used to specify CA certificate locations
		1879	instead of a system-dependent default.
		1880
		1881	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1882
		1883	When these are set to C<1>, then the respective modules are not
		1884	loaded. Mostly good for testing AnyEvent itself.
1283		1885
1284	=back	1886	=back
1285		1887
1286	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1888	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1287		1889
…		…
1345	warn "read: $input\n"; # output what has been read	1947	warn "read: $input\n"; # output what has been read
1346	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1948	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1347	},	1949	},
1348	);	1950	);
1349		1951
1350	my $time_watcher; # can only be used once
1351
1352	sub new_timer {
1353	$timer = AnyEvent->timer (after => 1, cb => sub {	1952	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1354	warn "timeout\n"; # print 'timeout' about every second	1953	warn "timeout\n"; # print 'timeout' at most every second
1355	&new_timer; # and restart the time
1356	});	1954	});
1357	}
1358
1359	new_timer; # create first timer
1360		1955
1361	$cv->recv; # wait until user enters /^q/i	1956	$cv->recv; # wait until user enters /^q/i
1362		1957
1363	=head1 REAL-WORLD EXAMPLE	1958	=head1 REAL-WORLD EXAMPLE
1364		1959
…		…
1495	through AnyEvent. The benchmark creates a lot of timers (with a zero	2090	through AnyEvent. The benchmark creates a lot of timers (with a zero
1496	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2091	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1497	which it is), lets them fire exactly once and destroys them again.	2092	which it is), lets them fire exactly once and destroys them again.
1498		2093
1499	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2094	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1500	distribution.	2095	distribution. It uses the L<AE> interface, which makes a real difference
		2096	for the EV and Perl backends only.
1501		2097
1502	=head3 Explanation of the columns	2098	=head3 Explanation of the columns
1503		2099
1504	I<watcher> is the number of event watchers created/destroyed. Since	2100	I<watcher> is the number of event watchers created/destroyed. Since
1505	different event models feature vastly different performances, each event	2101	different event models feature vastly different performances, each event
…		…
1526	watcher.	2122	watcher.
1527		2123
1528	=head3 Results	2124	=head3 Results
1529		2125
1530	name watchers bytes create invoke destroy comment	2126	name watchers bytes create invoke destroy comment
1531	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	2127	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1532	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	2128	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1533	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	2129	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1534	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	2130	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1535	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	2131	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1536	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	2132	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2133	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2134	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1537	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	2135	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1538	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	2136	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1539	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	2137	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1540	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	2138	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1541		2139
1542	=head3 Discussion	2140	=head3 Discussion
1543		2141
1544	The benchmark does I<not> measure scalability of the event loop very	2142	The benchmark does I<not> measure scalability of the event loop very
1545	well. For example, a select-based event loop (such as the pure perl one)	2143	well. For example, a select-based event loop (such as the pure perl one)
…		…
1557	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2155	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1558	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2156	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1559	cycles with POE.	2157	cycles with POE.
1560		2158
1561	C<EV> is the sole leader regarding speed and memory use, which are both	2159	C<EV> is the sole leader regarding speed and memory use, which are both
1562	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2160	maximal/minimal, respectively. When using the L<AE> API there is zero
		2161	overhead (when going through the AnyEvent API create is about 5-6 times
		2162	slower, with other times being equal, so still uses far less memory than
1563	far less memory than any other event loop and is still faster than Event	2163	any other event loop and is still faster than Event natively).
1564	natively.
1565		2164
1566	The pure perl implementation is hit in a few sweet spots (both the	2165	The pure perl implementation is hit in a few sweet spots (both the
1567	constant timeout and the use of a single fd hit optimisations in the perl	2166	constant timeout and the use of a single fd hit optimisations in the perl
1568	interpreter and the backend itself). Nevertheless this shows that it	2167	interpreter and the backend itself). Nevertheless this shows that it
1569	adds very little overhead in itself. Like any select-based backend its	2168	adds very little overhead in itself. Like any select-based backend its
1570	performance becomes really bad with lots of file descriptors (and few of	2169	performance becomes really bad with lots of file descriptors (and few of
1571	them active), of course, but this was not subject of this benchmark.	2170	them active), of course, but this was not subject of this benchmark.
1572		2171
1573	The C<Event> module has a relatively high setup and callback invocation	2172	The C<Event> module has a relatively high setup and callback invocation
1574	cost, but overall scores in on the third place.	2173	cost, but overall scores in on the third place.
		2174
		2175	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2176	when using its pure perl backend.
1575		2177
1576	C<Glib>'s memory usage is quite a bit higher, but it features a	2178	C<Glib>'s memory usage is quite a bit higher, but it features a
1577	faster callback invocation and overall ends up in the same class as	2179	faster callback invocation and overall ends up in the same class as
1578	C<Event>. However, Glib scales extremely badly, doubling the number of	2180	C<Event>. However, Glib scales extremely badly, doubling the number of
1579	watchers increases the processing time by more than a factor of four,	2181	watchers increases the processing time by more than a factor of four,
…		…
1640	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2242	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1641	(1%) are active. This mirrors the activity of large servers with many	2243	(1%) are active. This mirrors the activity of large servers with many
1642	connections, most of which are idle at any one point in time.	2244	connections, most of which are idle at any one point in time.
1643		2245
1644	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2246	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1645	distribution.	2247	distribution. It uses the L<AE> interface, which makes a real difference
		2248	for the EV and Perl backends only.
1646		2249
1647	=head3 Explanation of the columns	2250	=head3 Explanation of the columns
1648		2251
1649	I<sockets> is the number of sockets, and twice the number of "servers" (as	2252	I<sockets> is the number of sockets, and twice the number of "servers" (as
1650	each server has a read and write socket end).	2253	each server has a read and write socket end).
…		…
1657	it to another server. This includes deleting the old timeout and creating	2260	it to another server. This includes deleting the old timeout and creating
1658	a new one that moves the timeout into the future.	2261	a new one that moves the timeout into the future.
1659		2262
1660	=head3 Results	2263	=head3 Results
1661		2264
1662	name sockets create request	2265	name sockets create request
1663	EV 20000 69.01 11.16	2266	EV 20000 62.66 7.99
1664	Perl 20000 73.32 35.87	2267	Perl 20000 68.32 32.64
1665	Event 20000 212.62 257.32	2268	IOAsync 20000 174.06 101.15 epoll
1666	Glib 20000 651.16 1896.30	2269	IOAsync 20000 174.67 610.84 poll
		2270	Event 20000 202.69 242.91
		2271	Glib 20000 557.01 1689.52
1667	POE 20000 349.67 12317.24 uses POE::Loop::Event	2272	POE 20000 341.54 12086.32 uses POE::Loop::Event
1668		2273
1669	=head3 Discussion	2274	=head3 Discussion
1670		2275
1671	This benchmark I<does> measure scalability and overall performance of the	2276	This benchmark I<does> measure scalability and overall performance of the
1672	particular event loop.	2277	particular event loop.
…		…
1674	EV is again fastest. Since it is using epoll on my system, the setup time	2279	EV is again fastest. Since it is using epoll on my system, the setup time
1675	is relatively high, though.	2280	is relatively high, though.
1676		2281
1677	Perl surprisingly comes second. It is much faster than the C-based event	2282	Perl surprisingly comes second. It is much faster than the C-based event
1678	loops Event and Glib.	2283	loops Event and Glib.
		2284
		2285	IO::Async performs very well when using its epoll backend, and still quite
		2286	good compared to Glib when using its pure perl backend.
1679		2287
1680	Event suffers from high setup time as well (look at its code and you will	2288	Event suffers from high setup time as well (look at its code and you will
1681	understand why). Callback invocation also has a high overhead compared to	2289	understand why). Callback invocation also has a high overhead compared to
1682	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2290	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1683	uses select or poll in basically all documented configurations.	2291	uses select or poll in basically all documented configurations.
…		…
1746	=item * C-based event loops perform very well with small number of	2354	=item * C-based event loops perform very well with small number of
1747	watchers, as the management overhead dominates.	2355	watchers, as the management overhead dominates.
1748		2356
1749	=back	2357	=back
1750		2358
		2359	=head2 THE IO::Lambda BENCHMARK
		2360
		2361	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2362	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2363	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2364	shouldn't come as a surprise to anybody). As such, the benchmark is
		2365	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2366	very optimal. But how would AnyEvent compare when used without the extra
		2367	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2368
		2369	The benchmark itself creates an echo-server, and then, for 500 times,
		2370	connects to the echo server, sends a line, waits for the reply, and then
		2371	creates the next connection. This is a rather bad benchmark, as it doesn't
		2372	test the efficiency of the framework or much non-blocking I/O, but it is a
		2373	benchmark nevertheless.
		2374
		2375	name runtime
		2376	Lambda/select 0.330 sec
		2377	+ optimized 0.122 sec
		2378	Lambda/AnyEvent 0.327 sec
		2379	+ optimized 0.138 sec
		2380	Raw sockets/select 0.077 sec
		2381	POE/select, components 0.662 sec
		2382	POE/select, raw sockets 0.226 sec
		2383	POE/select, optimized 0.404 sec
		2384
		2385	AnyEvent/select/nb 0.085 sec
		2386	AnyEvent/EV/nb 0.068 sec
		2387	+state machine 0.134 sec
		2388
		2389	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2390	benchmarks actually make blocking connects and use 100% blocking I/O,
		2391	defeating the purpose of an event-based solution. All of the newly
		2392	written AnyEvent benchmarks use 100% non-blocking connects (using
		2393	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2394	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2395	generally require a lot more bookkeeping and event handling than blocking
		2396	connects (which involve a single syscall only).
		2397
		2398	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2399	offers similar expressive power as POE and IO::Lambda, using conventional
		2400	Perl syntax. This means that both the echo server and the client are 100%
		2401	non-blocking, further placing it at a disadvantage.
		2402
		2403	As you can see, the AnyEvent + EV combination even beats the
		2404	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2405	backend easily beats IO::Lambda and POE.
		2406
		2407	And even the 100% non-blocking version written using the high-level (and
		2408	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2409	higher level ("unoptimised") abstractions by a large margin, even though
		2410	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
		2411
		2412	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2413	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2414	part of the IO::Lambda distribution and were used without any changes.
		2415
		2416
		2417	=head1 SIGNALS
		2418
		2419	AnyEvent currently installs handlers for these signals:
		2420
		2421	=over 4
		2422
		2423	=item SIGCHLD
		2424
		2425	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		2426	emulation for event loops that do not support them natively. Also, some
		2427	event loops install a similar handler.
		2428
		2429	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2430	AnyEvent will reset it to default, to avoid losing child exit statuses.
		2431
		2432	=item SIGPIPE
		2433
		2434	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		2435	when AnyEvent gets loaded.
		2436
		2437	The rationale for this is that AnyEvent users usually do not really depend
		2438	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		2439	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		2440	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		2441	some random socket.
		2442
		2443	The rationale for installing a no-op handler as opposed to ignoring it is
		2444	that this way, the handler will be restored to defaults on exec.
		2445
		2446	Feel free to install your own handler, or reset it to defaults.
		2447
		2448	=back
		2449
		2450	=cut
		2451
		2452	undef $SIG{CHLD}
		2453	if $SIG{CHLD} eq 'IGNORE';
		2454
		2455	$SIG{PIPE} = sub { }
		2456	unless defined $SIG{PIPE};
		2457
		2458	=head1 RECOMMENDED/OPTIONAL MODULES
		2459
		2460	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2461	it's built-in modules) are required to use it.
		2462
		2463	That does not mean that AnyEvent won't take advantage of some additional
		2464	modules if they are installed.
		2465
		2466	This section explains which additional modules will be used, and how they
		2467	affect AnyEvent's operation.
		2468
		2469	=over 4
		2470
		2471	=item L<Async::Interrupt>
		2472
		2473	This slightly arcane module is used to implement fast signal handling: To
		2474	my knowledge, there is no way to do completely race-free and quick
		2475	signal handling in pure perl. To ensure that signals still get
		2476	delivered, AnyEvent will start an interval timer to wake up perl (and
		2477	catch the signals) with some delay (default is 10 seconds, look for
		2478	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2479
		2480	If this module is available, then it will be used to implement signal
		2481	catching, which means that signals will not be delayed, and the event loop
		2482	will not be interrupted regularly, which is more efficient (and good for
		2483	battery life on laptops).
		2484
		2485	This affects not just the pure-perl event loop, but also other event loops
		2486	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2487
		2488	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2489	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2490	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2491	does nothing for those backends.
		2492
		2493	=item L<EV>
		2494
		2495	This module isn't really "optional", as it is simply one of the backend
		2496	event loops that AnyEvent can use. However, it is simply the best event
		2497	loop available in terms of features, speed and stability: It supports
		2498	the AnyEvent API optimally, implements all the watcher types in XS, does
		2499	automatic timer adjustments even when no monotonic clock is available,
		2500	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2501	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2502	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2503
		2504	=item L<Guard>
		2505
		2506	The guard module, when used, will be used to implement
		2507	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2508	lot less memory), but otherwise doesn't affect guard operation much. It is
		2509	purely used for performance.
		2510
		2511	=item L<JSON> and L<JSON::XS>
		2512
		2513	One of these modules is required when you want to read or write JSON data
		2514	via L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2515	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2516
		2517	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2518	installed.
		2519
		2520	=item L<Net::SSLeay>
		2521
		2522	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2523	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2524	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2525
		2526	=item L<Time::HiRes>
		2527
		2528	This module is part of perl since release 5.008. It will be used when the
		2529	chosen event library does not come with a timing source on it's own. The
		2530	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2531	try to use a monotonic clock for timing stability.
		2532
		2533	=back
		2534
1751		2535
1752	=head1 FORK	2536	=head1 FORK
1753		2537
1754	Most event libraries are not fork-safe. The ones who are usually are	2538	Most event libraries are not fork-safe. The ones who are usually are
1755	because they rely on inefficient but fork-safe C<select> or C<poll>	2539	because they rely on inefficient but fork-safe C<select> or C<poll>
1756	calls. Only L<EV> is fully fork-aware.	2540	calls. Only L<EV> is fully fork-aware.
1757		2541
		2542	This means that, in general, you cannot fork and do event processing
		2543	in the child if a watcher was created before the fork (which in turn
		2544	initialises the event library).
		2545
1758	If you have to fork, you must either do so I<before> creating your first	2546	If you have to fork, you must either do so I<before> creating your first
1759	watcher OR you must not use AnyEvent at all in the child.	2547	watcher OR you must not use AnyEvent at all in the child OR you must do
		2548	something completely out of the scope of AnyEvent.
		2549
		2550	The problem of doing event processing in the parent I<and> the child
		2551	is much more complicated: even for backends that I<are> fork-aware or
		2552	fork-safe, their behaviour is not usually what you want: fork clones all
		2553	watchers, that means all timers, I/O watchers etc. are active in both
		2554	parent and child, which is almost never what you want.
1760		2555
1761		2556
1762	=head1 SECURITY CONSIDERATIONS	2557	=head1 SECURITY CONSIDERATIONS
1763		2558
1764	AnyEvent can be forced to load any event model via	2559	AnyEvent can be forced to load any event model via
…		…
1776	use AnyEvent;	2571	use AnyEvent;
1777		2572
1778	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2573	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1779	be used to probe what backend is used and gain other information (which is	2574	be used to probe what backend is used and gain other information (which is
1780	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2575	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1781	$ENV{PERL_ANYEGENT_STRICT}.	2576	$ENV{PERL_ANYEVENT_STRICT}.
		2577
		2578	Note that AnyEvent will remove I<all> environment variables starting with
		2579	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2580	enabled.
1782		2581
1783		2582
1784	=head1 BUGS	2583	=head1 BUGS
1785		2584
1786	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2585	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1787	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2586	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1788	and check wether the leaks still show up. (Perl 5.10.0 has other annoying	2587	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1789	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as	2588	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1790	pronounced).	2589	pronounced).
1791		2590
1792		2591
1793	=head1 SEE ALSO	2592	=head1 SEE ALSO
1794		2593
…		…
1798	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2597	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1799		2598
1800	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2599	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1801	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2600	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1802	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2601	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1803	L<AnyEvent::Impl::POE>.	2602	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1804		2603
1805	Non-blocking file handles, sockets, TCP clients and	2604	Non-blocking file handles, sockets, TCP clients and
1806	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2605	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1807		2606
1808	Asynchronous DNS: L<AnyEvent::DNS>.	2607	Asynchronous DNS: L<AnyEvent::DNS>.
1809		2608
1810	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2609	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2610	L<Coro::Event>,
1811		2611
1812	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2612	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2613	L<AnyEvent::HTTP>.
1813		2614
1814		2615
1815	=head1 AUTHOR	2616	=head1 AUTHOR
1816		2617
1817	Marc Lehmann <schmorp@schmorp.de>	2618	Marc Lehmann <schmorp@schmorp.de>

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