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Revision 1.185 by root, Thu Oct 2 15:11:01 2008 UTC vs.
Revision 1.296 by root, Tue Nov 17 01:19:49 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 $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
339		407
		408	=head3 Signal Races, Delays and Workarounds
		409
		410	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		411	callbacks to signals in a generic way, which is a pity, as you cannot
		412	do race-free signal handling in perl, requiring C libraries for
		413	this. AnyEvent will try to do it's best, which means in some cases,
		414	signals will be delayed. The maximum time a signal might be delayed is
		415	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		416	variable can be changed only before the first signal watcher is created,
		417	and should be left alone otherwise. This variable determines how often
		418	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		419	will cause fewer spurious wake-ups, which is better for power and CPU
		420	saving.
		421
		422	All these problems can be avoided by installing the optional
		423	L<Async::Interrupt> module, which works with most event loops. It will not
		424	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		425	(and not with L<POE> currently, as POE does it's own workaround with
		426	one-second latency). For those, you just have to suffer the delays.
		427
340	=head2 CHILD PROCESS WATCHERS	428	=head2 CHILD PROCESS WATCHERS
341		429
		430	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		431
342	You can also watch on a child process exit and catch its exit status.	432	You can also watch on a child process exit and catch its exit status.
343		433
344	The child process is specified by the C<pid> argument (if set to C<0>, it	434	The child process is specified by the C<pid> argument (one some backends,
345	watches for any child process exit). The watcher will triggered only when	435	using C<0> watches for any child process exit, on others this will
346	the child process has finished and an exit status is available, not on	436	croak). The watcher will be triggered only when the child process has
347	any trace events (stopped/continued).	437	finished and an exit status is available, not on any trace events
		438	(stopped/continued).
348		439
349	The callback will be called with the pid and exit status (as returned by	440	The callback will be called with the pid and exit status (as returned by
350	waitpid), so unlike other watcher types, you I<can> rely on child watcher	441	waitpid), so unlike other watcher types, you I<can> rely on child watcher
351	callback arguments.	442	callback arguments.
352		443
…		…
357		448
358	There is a slight catch to child watchers, however: you usually start them	449	There is a slight catch to child watchers, however: you usually start them
359	I<after> the child process was created, and this means the process could	450	I<after> the child process was created, and this means the process could
360	have exited already (and no SIGCHLD will be sent anymore).	451	have exited already (and no SIGCHLD will be sent anymore).
361		452
362	Not all event models handle this correctly (POE doesn't), but even for	453	Not all event models handle this correctly (neither POE nor IO::Async do,
		454	see their AnyEvent::Impl manpages for details), but even for event models
363	event models that I<do> handle this correctly, they usually need to be	455	that I<do> handle this correctly, they usually need to be loaded before
364	loaded before the process exits (i.e. before you fork in the first place).	456	the process exits (i.e. before you fork in the first place). AnyEvent's
		457	pure perl event loop handles all cases correctly regardless of when you
		458	start the watcher.
365		459
366	This means you cannot create a child watcher as the very first thing in an	460	This means you cannot create a child watcher as the very first
367	AnyEvent program, you I<have> to create at least one watcher before you	461	thing in an AnyEvent program, you I<have> to create at least one
368	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	462	watcher before you C<fork> the child (alternatively, you can call
		463	C<AnyEvent::detect>).
		464
		465	As most event loops do not support waiting for child events, they will be
		466	emulated by AnyEvent in most cases, in which the latency and race problems
		467	mentioned in the description of signal watchers apply.
369		468
370	Example: fork a process and wait for it	469	Example: fork a process and wait for it
371		470
372	my $done = AnyEvent->condvar;	471	my $done = AnyEvent->condvar;
373		472
…		…
383	);	482	);
384		483
385	# do something else, then wait for process exit	484	# do something else, then wait for process exit
386	$done->recv;	485	$done->recv;
387		486
		487	=head2 IDLE WATCHERS
		488
		489	$w = AnyEvent->idle (cb => <callback>);
		490
		491	Sometimes there is a need to do something, but it is not so important
		492	to do it instantly, but only when there is nothing better to do. This
		493	"nothing better to do" is usually defined to be "no other events need
		494	attention by the event loop".
		495
		496	Idle watchers ideally get invoked when the event loop has nothing
		497	better to do, just before it would block the process to wait for new
		498	events. Instead of blocking, the idle watcher is invoked.
		499
		500	Most event loops unfortunately do not really support idle watchers (only
		501	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		502	will simply call the callback "from time to time".
		503
		504	Example: read lines from STDIN, but only process them when the
		505	program is otherwise idle:
		506
		507	my @lines; # read data
		508	my $idle_w;
		509	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		510	push @lines, scalar <STDIN>;
		511
		512	# start an idle watcher, if not already done
		513	$idle_w ||= AnyEvent->idle (cb => sub {
		514	# handle only one line, when there are lines left
		515	if (my $line = shift @lines) {
		516	print "handled when idle: $line";
		517	} else {
		518	# otherwise disable the idle watcher again
		519	undef $idle_w;
		520	}
		521	});
		522	});
		523
388	=head2 CONDITION VARIABLES	524	=head2 CONDITION VARIABLES
		525
		526	$cv = AnyEvent->condvar;
		527
		528	$cv->send (<list>);
		529	my @res = $cv->recv;
389		530
390	If you are familiar with some event loops you will know that all of them	531	If you are familiar with some event loops you will know that all of them
391	require you to run some blocking "loop", "run" or similar function that	532	require you to run some blocking "loop", "run" or similar function that
392	will actively watch for new events and call your callbacks.	533	will actively watch for new events and call your callbacks.
393		534
394	AnyEvent is different, it expects somebody else to run the event loop and	535	AnyEvent is slightly different: it expects somebody else to run the event
395	will only block when necessary (usually when told by the user).	536	loop and will only block when necessary (usually when told by the user).
396		537
397	The instrument to do that is called a "condition variable", so called	538	The instrument to do that is called a "condition variable", so called
398	because they represent a condition that must become true.	539	because they represent a condition that must become true.
399		540
		541	Now is probably a good time to look at the examples further below.
		542
400	Condition variables can be created by calling the C<< AnyEvent->condvar	543	Condition variables can be created by calling the C<< AnyEvent->condvar
401	>> method, usually without arguments. The only argument pair allowed is	544	>> method, usually without arguments. The only argument pair allowed is
402
403	C<cb>, which specifies a callback to be called when the condition variable	545	C<cb>, which specifies a callback to be called when the condition variable
404	becomes true, with the condition variable as the first argument (but not	546	becomes true, with the condition variable as the first argument (but not
405	the results).	547	the results).
406		548
407	After creation, the condition variable is "false" until it becomes "true"	549	After creation, the condition variable is "false" until it becomes "true"
…		…
412	Condition variables are similar to callbacks, except that you can	554	Condition variables are similar to callbacks, except that you can
413	optionally wait for them. They can also be called merge points - points	555	optionally wait for them. They can also be called merge points - points
414	in time where multiple outstanding events have been processed. And yet	556	in time where multiple outstanding events have been processed. And yet
415	another way to call them is transactions - each condition variable can be	557	another way to call them is transactions - each condition variable can be
416	used to represent a transaction, which finishes at some point and delivers	558	used to represent a transaction, which finishes at some point and delivers
417	a result.	559	a result. And yet some people know them as "futures" - a promise to
		560	compute/deliver something that you can wait for.
418		561
419	Condition variables are very useful to signal that something has finished,	562	Condition variables are very useful to signal that something has finished,
420	for example, if you write a module that does asynchronous http requests,	563	for example, if you write a module that does asynchronous http requests,
421	then a condition variable would be the ideal candidate to signal the	564	then a condition variable would be the ideal candidate to signal the
422	availability of results. The user can either act when the callback is	565	availability of results. The user can either act when the callback is
…		…
456	after => 1,	599	after => 1,
457	cb => sub { $result_ready->send },	600	cb => sub { $result_ready->send },
458	);	601	);
459		602
460	# this "blocks" (while handling events) till the callback	603	# this "blocks" (while handling events) till the callback
461	# calls send	604	# calls ->send
462	$result_ready->recv;	605	$result_ready->recv;
463		606
464	Example: wait for a timer, but take advantage of the fact that	607	Example: wait for a timer, but take advantage of the fact that condition
465	condition variables are also code references.	608	variables are also callable directly.
466		609
467	my $done = AnyEvent->condvar;	610	my $done = AnyEvent->condvar;
468	my $delay = AnyEvent->timer (after => 5, cb => $done);	611	my $delay = AnyEvent->timer (after => 5, cb => $done);
469	$done->recv;	612	$done->recv;
470		613
…		…
476		619
477	...	620	...
478		621
479	my @info = $couchdb->info->recv;	622	my @info = $couchdb->info->recv;
480		623
481	And this is how you would just ste a callback to be called whenever the	624	And this is how you would just set a callback to be called whenever the
482	results are available:	625	results are available:
483		626
484	$couchdb->info->cb (sub {	627	$couchdb->info->cb (sub {
485	my @info = $_[0]->recv;	628	my @info = $_[0]->recv;
486	});	629	});
…		…
504	immediately from within send.	647	immediately from within send.
505		648
506	Any arguments passed to the C<send> call will be returned by all	649	Any arguments passed to the C<send> call will be returned by all
507	future C<< ->recv >> calls.	650	future C<< ->recv >> calls.
508		651
509	Condition variables are overloaded so one can call them directly	652	Condition variables are overloaded so one can call them directly (as if
510	(as a code reference). Calling them directly is the same as calling	653	they were a code reference). Calling them directly is the same as calling
511	C<send>. Note, however, that many C-based event loops do not handle	654	C<send>.
512	overloading, so as tempting as it may be, passing a condition variable
513	instead of a callback does not work. Both the pure perl and EV loops
514	support overloading, however, as well as all functions that use perl to
515	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
516	example).
517		655
518	=item $cv->croak ($error)	656	=item $cv->croak ($error)
519		657
520	Similar to send, but causes all call's to C<< ->recv >> to invoke	658	Similar to send, but causes all call's to C<< ->recv >> to invoke
521	C<Carp::croak> with the given error message/object/scalar.	659	C<Carp::croak> with the given error message/object/scalar.
522		660
523	This can be used to signal any errors to the condition variable	661	This can be used to signal any errors to the condition variable
524	user/consumer.	662	user/consumer. Doing it this way instead of calling C<croak> directly
		663	delays the error detetcion, but has the overwhelmign advantage that it
		664	diagnoses the error at the place where the result is expected, and not
		665	deep in some event clalback without connection to the actual code causing
		666	the problem.
525		667
526	=item $cv->begin ([group callback])	668	=item $cv->begin ([group callback])
527		669
528	=item $cv->end	670	=item $cv->end
529
530	These two methods are EXPERIMENTAL and MIGHT CHANGE.
531		671
532	These two methods can be used to combine many transactions/events into	672	These two methods can be used to combine many transactions/events into
533	one. For example, a function that pings many hosts in parallel might want	673	one. For example, a function that pings many hosts in parallel might want
534	to use a condition variable for the whole process.	674	to use a condition variable for the whole process.
535		675
536	Every call to C<< ->begin >> will increment a counter, and every call to	676	Every call to C<< ->begin >> will increment a counter, and every call to
537	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	677	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
538	>>, the (last) callback passed to C<begin> will be executed. That callback	678	>>, the (last) callback passed to C<begin> will be executed, passing the
539	is I<supposed> to call C<< ->send >>, but that is not required. If no	679	condvar as first argument. That callback is I<supposed> to call C<< ->send
540	callback was set, C<send> will be called without any arguments.	680	>>, but that is not required. If no group callback was set, C<send> will
		681	be called without any arguments.
541		682
542	Let's clarify this with the ping example:	683	You can think of C<< $cv->send >> giving you an OR condition (one call
		684	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		685	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		686
		687	Let's start with a simple example: you have two I/O watchers (for example,
		688	STDOUT and STDERR for a program), and you want to wait for both streams to
		689	close before activating a condvar:
543		690
544	my $cv = AnyEvent->condvar;	691	my $cv = AnyEvent->condvar;
545		692
		693	$cv->begin; # first watcher
		694	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		695	defined sysread $fh1, my $buf, 4096
		696	or $cv->end;
		697	});
		698
		699	$cv->begin; # second watcher
		700	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		701	defined sysread $fh2, my $buf, 4096
		702	or $cv->end;
		703	});
		704
		705	$cv->recv;
		706
		707	This works because for every event source (EOF on file handle), there is
		708	one call to C<begin>, so the condvar waits for all calls to C<end> before
		709	sending.
		710
		711	The ping example mentioned above is slightly more complicated, as the
		712	there are results to be passwd back, and the number of tasks that are
		713	begung can potentially be zero:
		714
		715	my $cv = AnyEvent->condvar;
		716
546	my %result;	717	my %result;
547	$cv->begin (sub { $cv->send (\%result) });	718	$cv->begin (sub { shift->send (\%result) });
548		719
549	for my $host (@list_of_hosts) {	720	for my $host (@list_of_hosts) {
550	$cv->begin;	721	$cv->begin;
551	ping_host_then_call_callback $host, sub {	722	ping_host_then_call_callback $host, sub {
552	$result{$host} = ...;	723	$result{$host} = ...;
…		…
567	loop, which serves two important purposes: first, it sets the callback	738	loop, which serves two important purposes: first, it sets the callback
568	to be called once the counter reaches C<0>, and second, it ensures that	739	to be called once the counter reaches C<0>, and second, it ensures that
569	C<send> is called even when C<no> hosts are being pinged (the loop	740	C<send> is called even when C<no> hosts are being pinged (the loop
570	doesn't execute once).	741	doesn't execute once).
571		742
572	This is the general pattern when you "fan out" into multiple subrequests:	743	This is the general pattern when you "fan out" into multiple (but
573	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	744	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
574	is called at least once, and then, for each subrequest you start, call	745	the callback and ensure C<end> is called at least once, and then, for each
575	C<begin> and for each subrequest you finish, call C<end>.	746	subrequest you start, call C<begin> and for each subrequest you finish,
		747	call C<end>.
576		748
577	=back	749	=back
578		750
579	=head3 METHODS FOR CONSUMERS	751	=head3 METHODS FOR CONSUMERS
580		752
…		…
596	function will call C<croak>.	768	function will call C<croak>.
597		769
598	In list context, all parameters passed to C<send> will be returned,	770	In list context, all parameters passed to C<send> will be returned,
599	in scalar context only the first one will be returned.	771	in scalar context only the first one will be returned.
600		772
		773	Note that doing a blocking wait in a callback is not supported by any
		774	event loop, that is, recursive invocation of a blocking C<< ->recv
		775	>> is not allowed, and the C<recv> call will C<croak> if such a
		776	condition is detected. This condition can be slightly loosened by using
		777	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		778	any thread that doesn't run the event loop itself.
		779
601	Not all event models support a blocking wait - some die in that case	780	Not all event models support a blocking wait - some die in that case
602	(programs might want to do that to stay interactive), so I<if you are	781	(programs might want to do that to stay interactive), so I<if you are
603	using this from a module, never require a blocking wait>, but let the	782	using this from a module, never require a blocking wait>. Instead, let the
604	caller decide whether the call will block or not (for example, by coupling	783	caller decide whether the call will block or not (for example, by coupling
605	condition variables with some kind of request results and supporting	784	condition variables with some kind of request results and supporting
606	callbacks so the caller knows that getting the result will not block,	785	callbacks so the caller knows that getting the result will not block,
607	while still supporting blocking waits if the caller so desires).	786	while still supporting blocking waits if the caller so desires).
608		787
609	Another reason I<never> to C<< ->recv >> in a module is that you cannot
610	sensibly have two C<< ->recv >>'s in parallel, as that would require
611	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
612	can supply.
613
614	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
615	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
616	versions and also integrates coroutines into AnyEvent, making blocking
617	C<< ->recv >> calls perfectly safe as long as they are done from another
618	coroutine (one that doesn't run the event loop).
619
620	You can ensure that C<< -recv >> never blocks by setting a callback and	788	You can ensure that C<< -recv >> never blocks by setting a callback and
621	only calling C<< ->recv >> from within that callback (or at a later	789	only calling C<< ->recv >> from within that callback (or at a later
622	time). This will work even when the event loop does not support blocking	790	time). This will work even when the event loop does not support blocking
623	waits otherwise.	791	waits otherwise.
624		792
…		…
630	=item $cb = $cv->cb ($cb->($cv))	798	=item $cb = $cv->cb ($cb->($cv))
631		799
632	This is a mutator function that returns the callback set and optionally	800	This is a mutator function that returns the callback set and optionally
633	replaces it before doing so.	801	replaces it before doing so.
634		802
635	The callback will be called when the condition becomes "true", i.e. when	803	The callback will be called when the condition becomes (or already was)
636	C<send> or C<croak> are called, with the only argument being the condition	804	"true", i.e. when C<send> or C<croak> are called (or were called), with
637	variable itself. Calling C<recv> inside the callback or at any later time	805	the only argument being the condition variable itself. Calling C<recv>
638	is guaranteed not to block.	806	inside the callback or at any later time is guaranteed not to block.
639		807
640	=back	808	=back
641		809
		810	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		811
		812	The available backend classes are (every class has its own manpage):
		813
		814	=over 4
		815
		816	=item Backends that are autoprobed when no other event loop can be found.
		817
		818	EV is the preferred backend when no other event loop seems to be in
		819	use. If EV is not installed, then AnyEvent will fall back to its own
		820	pure-perl implementation, which is available everywhere as it comes with
		821	AnyEvent itself.
		822
		823	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		824	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		825
		826	=item Backends that are transparently being picked up when they are used.
		827
		828	These will be used when they are currently loaded when the first watcher
		829	is created, in which case it is assumed that the application is using
		830	them. This means that AnyEvent will automatically pick the right backend
		831	when the main program loads an event module before anything starts to
		832	create watchers. Nothing special needs to be done by the main program.
		833
		834	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		835	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		836	AnyEvent::Impl::Tk based on Tk, very broken.
		837	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		838	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		839	AnyEvent::Impl::Irssi used when running within irssi.
		840
		841	=item Backends with special needs.
		842
		843	Qt requires the Qt::Application to be instantiated first, but will
		844	otherwise be picked up automatically. As long as the main program
		845	instantiates the application before any AnyEvent watchers are created,
		846	everything should just work.
		847
		848	AnyEvent::Impl::Qt based on Qt.
		849
		850	Support for IO::Async can only be partial, as it is too broken and
		851	architecturally limited to even support the AnyEvent API. It also
		852	is the only event loop that needs the loop to be set explicitly, so
		853	it can only be used by a main program knowing about AnyEvent. See
		854	L<AnyEvent::Impl::Async> for the gory details.
		855
		856	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		857
		858	=item Event loops that are indirectly supported via other backends.
		859
		860	Some event loops can be supported via other modules:
		861
		862	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		863
		864	B<WxWidgets> has no support for watching file handles. However, you can
		865	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		866	polls 20 times per second, which was considered to be too horrible to even
		867	consider for AnyEvent.
		868
		869	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		870	backend, so it can be supported through POE.
		871
		872	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		873	load L<POE> when detecting them, in the hope that POE will pick them up,
		874	in which case everything will be automatic.
		875
		876	=back
		877
642	=head1 GLOBAL VARIABLES AND FUNCTIONS	878	=head1 GLOBAL VARIABLES AND FUNCTIONS
643		879
		880	These are not normally required to use AnyEvent, but can be useful to
		881	write AnyEvent extension modules.
		882
644	=over 4	883	=over 4
645		884
646	=item $AnyEvent::MODEL	885	=item $AnyEvent::MODEL
647		886
648	Contains C<undef> until the first watcher is being created. Then it	887	Contains C<undef> until the first watcher is being created, before the
		888	backend has been autodetected.
		889
649	contains the event model that is being used, which is the name of the	890	Afterwards it contains the event model that is being used, which is the
650	Perl class implementing the model. This class is usually one of the	891	name of the Perl class implementing the model. This class is usually one
651	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	892	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
652	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	893	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
653		894	will be C<urxvt::anyevent>).
654	The known classes so far are:
655
656	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
657	AnyEvent::Impl::Event based on Event, second best choice.
658	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
659	AnyEvent::Impl::Glib based on Glib, third-best choice.
660	AnyEvent::Impl::Tk based on Tk, very bad choice.
661	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
662	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
663	AnyEvent::Impl::POE based on POE, not generic enough for full support.
664
665	There is no support for WxWidgets, as WxWidgets has no support for
666	watching file handles. However, you can use WxWidgets through the
667	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
668	second, which was considered to be too horrible to even consider for
669	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
670	it's adaptor.
671
672	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
673	autodetecting them.
674		895
675	=item AnyEvent::detect	896	=item AnyEvent::detect
676		897
677	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	898	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
678	if necessary. You should only call this function right before you would	899	if necessary. You should only call this function right before you would
679	have created an AnyEvent watcher anyway, that is, as late as possible at	900	have created an AnyEvent watcher anyway, that is, as late as possible at
680	runtime.	901	runtime, and not e.g. while initialising of your module.
		902
		903	If you need to do some initialisation before AnyEvent watchers are
		904	created, use C<post_detect>.
681		905
682	=item $guard = AnyEvent::post_detect { BLOCK }	906	=item $guard = AnyEvent::post_detect { BLOCK }
683		907
684	Arranges for the code block to be executed as soon as the event model is	908	Arranges for the code block to be executed as soon as the event model is
685	autodetected (or immediately if this has already happened).	909	autodetected (or immediately if this has already happened).
686		910
		911	The block will be executed I<after> the actual backend has been detected
		912	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		913	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		914	other initialisations - see the sources of L<AnyEvent::Strict> or
		915	L<AnyEvent::AIO> to see how this is used.
		916
		917	The most common usage is to create some global watchers, without forcing
		918	event module detection too early, for example, L<AnyEvent::AIO> creates
		919	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		920	avoid autodetecting the event module at load time.
		921
687	If called in scalar or list context, then it creates and returns an object	922	If called in scalar or list context, then it creates and returns an object
688	that automatically removes the callback again when it is destroyed. See	923	that automatically removes the callback again when it is destroyed (or
		924	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
689	L<Coro::BDB> for a case where this is useful.	925	a case where this is useful.
		926
		927	Example: Create a watcher for the IO::AIO module and store it in
		928	C<$WATCHER>. Only do so after the event loop is initialised, though.
		929
		930	our WATCHER;
		931
		932	my $guard = AnyEvent::post_detect {
		933	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		934	};
		935
		936	# the ||= is important in case post_detect immediately runs the block,
		937	# as to not clobber the newly-created watcher. assigning both watcher and
		938	# post_detect guard to the same variable has the advantage of users being
		939	# able to just C<undef $WATCHER> if the watcher causes them grief.
		940
		941	$WATCHER ||= $guard;
690		942
691	=item @AnyEvent::post_detect	943	=item @AnyEvent::post_detect
692		944
693	If there are any code references in this array (you can C<push> to it	945	If there are any code references in this array (you can C<push> to it
694	before or after loading AnyEvent), then they will called directly after	946	before or after loading AnyEvent), then they will called directly after
695	the event loop has been chosen.	947	the event loop has been chosen.
696		948
697	You should check C<$AnyEvent::MODEL> before adding to this array, though:	949	You should check C<$AnyEvent::MODEL> before adding to this array, though:
698	if it contains a true value then the event loop has already been detected,	950	if it is defined then the event loop has already been detected, and the
699	and the array will be ignored.	951	array will be ignored.
700		952
701	Best use C<AnyEvent::post_detect { BLOCK }> instead.	953	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		954	it,as it takes care of these details.
		955
		956	This variable is mainly useful for modules that can do something useful
		957	when AnyEvent is used and thus want to know when it is initialised, but do
		958	not need to even load it by default. This array provides the means to hook
		959	into AnyEvent passively, without loading it.
702		960
703	=back	961	=back
704		962
705	=head1 WHAT TO DO IN A MODULE	963	=head1 WHAT TO DO IN A MODULE
706		964
…		…
761		1019
762		1020
763	=head1 OTHER MODULES	1021	=head1 OTHER MODULES
764		1022
765	The following is a non-exhaustive list of additional modules that use	1023	The following is a non-exhaustive list of additional modules that use
766	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1024	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
767	in the same program. Some of the modules come with AnyEvent, some are	1025	modules and other event loops in the same program. Some of the modules
768	available via CPAN.	1026	come with AnyEvent, most are available via CPAN.
769		1027
770	=over 4	1028	=over 4
771		1029
772	=item L<AnyEvent::Util>	1030	=item L<AnyEvent::Util>
773		1031
…		…
782		1040
783	=item L<AnyEvent::Handle>	1041	=item L<AnyEvent::Handle>
784		1042
785	Provide read and write buffers, manages watchers for reads and writes,	1043	Provide read and write buffers, manages watchers for reads and writes,
786	supports raw and formatted I/O, I/O queued and fully transparent and	1044	supports raw and formatted I/O, I/O queued and fully transparent and
787	non-blocking SSL/TLS.	1045	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
788		1046
789	=item L<AnyEvent::DNS>	1047	=item L<AnyEvent::DNS>
790		1048
791	Provides rich asynchronous DNS resolver capabilities.	1049	Provides rich asynchronous DNS resolver capabilities.
792		1050
…		…
820		1078
821	=item L<AnyEvent::GPSD>	1079	=item L<AnyEvent::GPSD>
822		1080
823	A non-blocking interface to gpsd, a daemon delivering GPS information.	1081	A non-blocking interface to gpsd, a daemon delivering GPS information.
824		1082
		1083	=item L<AnyEvent::IRC>
		1084
		1085	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1086
		1087	=item L<AnyEvent::XMPP>
		1088
		1089	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1090	Net::XMPP2>.
		1091
825	=item L<AnyEvent::IGS>	1092	=item L<AnyEvent::IGS>
826		1093
827	A non-blocking interface to the Internet Go Server protocol (used by	1094	A non-blocking interface to the Internet Go Server protocol (used by
828	L<App::IGS>).	1095	L<App::IGS>).
829		1096
830	=item L<AnyEvent::IRC>
831
832	AnyEvent based IRC client module family (replacing the older Net::IRC3).
833
834	=item L<Net::XMPP2>
835
836	AnyEvent based XMPP (Jabber protocol) module family.
837
838	=item L<Net::FCP>	1097	=item L<Net::FCP>
839		1098
840	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1099	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
841	of AnyEvent.	1100	of AnyEvent.
842		1101
…		…
846		1105
847	=item L<Coro>	1106	=item L<Coro>
848		1107
849	Has special support for AnyEvent via L<Coro::AnyEvent>.	1108	Has special support for AnyEvent via L<Coro::AnyEvent>.
850		1109
851	=item L<IO::Lambda>
852
853	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
854
855	=back	1110	=back
856		1111
857	=cut	1112	=cut
858		1113
859	package AnyEvent;	1114	package AnyEvent;
860		1115
861	no warnings;	1116	# basically a tuned-down version of common::sense
		1117	sub common_sense {
		1118	# from common:.sense 1.0
		1119	${^WARNING_BITS} = "\xfc\x3f\xf3\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x03";
862	use strict qw(vars subs);	1120	# use strict vars subs
		1121	$^H |= 0x00000600;
		1122	}
863		1123
		1124	BEGIN { AnyEvent::common_sense }
		1125
864	use Carp;	1126	use Carp ();
865		1127
866	our $VERSION = 4.3;	1128	our $VERSION = '5.202';
867	our $MODEL;	1129	our $MODEL;
868		1130
869	our $AUTOLOAD;	1131	our $AUTOLOAD;
870	our @ISA;	1132	our @ISA;
871		1133
872	our @REGISTRY;	1134	our @REGISTRY;
873		1135
874	our $WIN32;	1136	our $WIN32;
875		1137
		1138	our $VERBOSE;
		1139
876	BEGIN {	1140	BEGIN {
877	my $win32 = ! ! ($^O =~ /mswin32/i);	1141	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
878	eval "sub WIN32(){ $win32 }";	1142	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
879	}
880		1143
		1144	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1145	if ${^TAINT};
		1146
881	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1147	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1148
		1149	}
		1150
		1151	our $MAX_SIGNAL_LATENCY = 10;
882		1152
883	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1153	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
884		1154
885	{	1155	{
886	my $idx;	1156	my $idx;
…		…
888	for reverse split /\s*,\s*/,	1158	for reverse split /\s*,\s*/,
889	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1159	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
890	}	1160	}
891		1161
892	my @models = (	1162	my @models = (
893	[EV:: => AnyEvent::Impl::EV::],	1163	[EV:: => AnyEvent::Impl::EV:: , 1],
894	[Event:: => AnyEvent::Impl::Event::],
895	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1164	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
896	# everything below here will not be autoprobed	1165	# everything below here will not (normally) be autoprobed
897	# as the pureperl backend should work everywhere	1166	# as the pureperl backend should work everywhere
898	# and is usually faster	1167	# and is usually faster
		1168	[Event:: => AnyEvent::Impl::Event::, 1],
		1169	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1170	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1171	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
899	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1172	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
900	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
901	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
902	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1173	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
903	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1174	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
904	[Wx:: => AnyEvent::Impl::POE::],	1175	[Wx:: => AnyEvent::Impl::POE::],
905	[Prima:: => AnyEvent::Impl::POE::],	1176	[Prima:: => AnyEvent::Impl::POE::],
		1177	# IO::Async is just too broken - we would need workarounds for its
		1178	# byzantine signal and broken child handling, among others.
		1179	# IO::Async is rather hard to detect, as it doesn't have any
		1180	# obvious default class.
		1181	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1182	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1183	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1184	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
906	);	1185	);
907		1186
908	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1187	our %method = map +($_ => 1),
		1188	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
909		1189
910	our @post_detect;	1190	our @post_detect;
911		1191
912	sub post_detect(&) {	1192	sub post_detect(&) {
913	my ($cb) = @_;	1193	my ($cb) = @_;
914		1194
915	if ($MODEL) {	1195	if ($MODEL) {
916	$cb->();	1196	$cb->();
917		1197
918	1	1198	undef
919	} else {	1199	} else {
920	push @post_detect, $cb;	1200	push @post_detect, $cb;
921		1201
922	defined wantarray	1202	defined wantarray
923	? bless \$cb, "AnyEvent::Util::PostDetect"	1203	? bless \$cb, "AnyEvent::Util::postdetect"
924	: ()	1204	: ()
925	}	1205	}
926	}	1206	}
927		1207
928	sub AnyEvent::Util::PostDetect::DESTROY {	1208	sub AnyEvent::Util::postdetect::DESTROY {
929	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1209	@post_detect = grep $_ != ${$_[0]}, @post_detect;
930	}	1210	}
931		1211
932	sub detect() {	1212	sub detect() {
933	unless ($MODEL) {	1213	unless ($MODEL) {
934	no strict 'refs';
935	local $SIG{__DIE__};	1214	local $SIG{__DIE__};
936		1215
937	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1216	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
938	my $model = "AnyEvent::Impl::$1";	1217	my $model = "AnyEvent::Impl::$1";
939	if (eval "require $model") {	1218	if (eval "require $model") {
940	$MODEL = $model;	1219	$MODEL = $model;
941	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1220	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
942	} else {	1221	} else {
943	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1222	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
944	}	1223	}
945	}	1224	}
946		1225
947	# check for already loaded models	1226	# check for already loaded models
948	unless ($MODEL) {	1227	unless ($MODEL) {
949	for (@REGISTRY, @models) {	1228	for (@REGISTRY, @models) {
950	my ($package, $model) = @$_;	1229	my ($package, $model) = @$_;
951	if (${"$package\::VERSION"} > 0) {	1230	if (${"$package\::VERSION"} > 0) {
952	if (eval "require $model") {	1231	if (eval "require $model") {
953	$MODEL = $model;	1232	$MODEL = $model;
954	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1233	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
955	last;	1234	last;
956	}	1235	}
957	}	1236	}
958	}	1237	}
959		1238
960	unless ($MODEL) {	1239	unless ($MODEL) {
961	# try to load a model	1240	# try to autoload a model
962
963	for (@REGISTRY, @models) {	1241	for (@REGISTRY, @models) {
964	my ($package, $model) = @$_;	1242	my ($package, $model, $autoload) = @$_;
		1243	if (
		1244	$autoload
965	if (eval "require $package"	1245	and eval "require $package"
966	and ${"$package\::VERSION"} > 0	1246	and ${"$package\::VERSION"} > 0
967	and eval "require $model") {	1247	and eval "require $model"
		1248	) {
968	$MODEL = $model;	1249	$MODEL = $model;
969	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1250	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
970	last;	1251	last;
971	}	1252	}
972	}	1253	}
973		1254
974	$MODEL	1255	$MODEL
975	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1256	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
976	}	1257	}
977	}	1258	}
978		1259
979	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1260	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
980		1261
…		…
990		1271
991	sub AUTOLOAD {	1272	sub AUTOLOAD {
992	(my $func = $AUTOLOAD) =~ s/.*://;	1273	(my $func = $AUTOLOAD) =~ s/.*://;
993		1274
994	$method{$func}	1275	$method{$func}
995	or croak "$func: not a valid method for AnyEvent objects";	1276	or Carp::croak "$func: not a valid method for AnyEvent objects";
996		1277
997	detect unless $MODEL;	1278	detect unless $MODEL;
998		1279
999	my $class = shift;	1280	my $class = shift;
1000	$class->$func (@_);	1281	$class->$func (@_);
1001	}	1282	}
1002		1283
1003	# utility function to dup a filehandle. this is used by many backends	1284	# utility function to dup a filehandle. this is used by many backends
1004	# to support binding more than one watcher per filehandle (they usually	1285	# to support binding more than one watcher per filehandle (they usually
1005	# allow only one watcher per fd, so we dup it to get a different one).	1286	# allow only one watcher per fd, so we dup it to get a different one).
1006	sub _dupfh($$$$) {	1287	sub _dupfh($$;$$) {
1007	my ($poll, $fh, $r, $w) = @_;	1288	my ($poll, $fh, $r, $w) = @_;
1008		1289
1009	require Fcntl;
1010
1011	# cygwin requires the fh mode to be matching, unix doesn't	1290	# cygwin requires the fh mode to be matching, unix doesn't
1012	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1291	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1013	: $poll eq "w" ? ($w, ">")
1014	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1015		1292
1016	open my $fh2, "$mode&" . fileno $fh	1293	open my $fh2, $mode, $fh
1017	or die "cannot dup() filehandle: $!";	1294	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1018		1295
1019	# we assume CLOEXEC is already set by perl in all important cases	1296	# we assume CLOEXEC is already set by perl in all important cases
1020		1297
1021	($fh2, $rw)	1298	($fh2, $rw)
1022	}	1299	}
1023		1300
		1301	=head1 SIMPLIFIED AE API
		1302
		1303	Starting with version 5.0, AnyEvent officially supports a second, much
		1304	simpler, API that is designed to reduce the calling, typing and memory
		1305	overhead.
		1306
		1307	See the L<AE> manpage for details.
		1308
		1309	=cut
		1310
		1311	package AE;
		1312
		1313	our $VERSION = $AnyEvent::VERSION;
		1314
		1315	sub io($$$) {
		1316	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1317	}
		1318
		1319	sub timer($$$) {
		1320	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1321	}
		1322
		1323	sub signal($$) {
		1324	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1325	}
		1326
		1327	sub child($$) {
		1328	AnyEvent->child (pid => $_[0], cb => $_[1])
		1329	}
		1330
		1331	sub idle($) {
		1332	AnyEvent->idle (cb => $_[0])
		1333	}
		1334
		1335	sub cv(;&) {
		1336	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1337	}
		1338
		1339	sub now() {
		1340	AnyEvent->now
		1341	}
		1342
		1343	sub now_update() {
		1344	AnyEvent->now_update
		1345	}
		1346
		1347	sub time() {
		1348	AnyEvent->time
		1349	}
		1350
1024	package AnyEvent::Base;	1351	package AnyEvent::Base;
1025		1352
1026	# default implementation for now and time	1353	# default implementations for many methods
1027		1354
1028	BEGIN {	1355	sub _time() {
		1356	# probe for availability of Time::HiRes
1029	if (eval "use Time::HiRes (); time (); 1") {	1357	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1358	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1030	*_time = \&Time::HiRes::time;	1359	*_time = \&Time::HiRes::time;
1031	# if (eval "use POSIX (); (POSIX::times())...	1360	# if (eval "use POSIX (); (POSIX::times())...
1032	} else {	1361	} else {
		1362	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1033	*_time = sub { time }; # epic fail	1363	*_time = sub { time }; # epic fail
1034	}	1364	}
		1365
		1366	&_time
1035	}	1367	}
1036		1368
1037	sub time { _time }	1369	sub time { _time }
1038	sub now { _time }	1370	sub now { _time }
		1371	sub now_update { }
1039		1372
1040	# default implementation for ->condvar	1373	# default implementation for ->condvar
1041		1374
1042	sub condvar {	1375	sub condvar {
1043	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1376	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1044	}	1377	}
1045		1378
1046	# default implementation for ->signal	1379	# default implementation for ->signal
1047		1380
1048	our %SIG_CB;	1381	our $HAVE_ASYNC_INTERRUPT;
		1382
		1383	sub _have_async_interrupt() {
		1384	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1385	&& eval "use Async::Interrupt 1.02 (); 1")
		1386	unless defined $HAVE_ASYNC_INTERRUPT;
		1387
		1388	$HAVE_ASYNC_INTERRUPT
		1389	}
		1390
		1391	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1392	our (%SIG_ASY, %SIG_ASY_W);
		1393	our ($SIG_COUNT, $SIG_TW);
		1394
		1395	sub _signal_exec {
		1396	$HAVE_ASYNC_INTERRUPT
		1397	? $SIGPIPE_R->drain
		1398	: sysread $SIGPIPE_R, (my $dummy), 9;
		1399
		1400	while (%SIG_EV) {
		1401	for (keys %SIG_EV) {
		1402	delete $SIG_EV{$_};
		1403	$_->() for values %{ $SIG_CB{$_} || {} };
		1404	}
		1405	}
		1406	}
		1407
		1408	# install a dummy wakeup watcher to reduce signal catching latency
		1409	sub _sig_add() {
		1410	unless ($SIG_COUNT++) {
		1411	# try to align timer on a full-second boundary, if possible
		1412	my $NOW = AE::now;
		1413
		1414	$SIG_TW = AE::timer
		1415	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1416	$MAX_SIGNAL_LATENCY,
		1417	sub { } # just for the PERL_ASYNC_CHECK
		1418	;
		1419	}
		1420	}
		1421
		1422	sub _sig_del {
		1423	undef $SIG_TW
		1424	unless --$SIG_COUNT;
		1425	}
		1426
		1427	our $_sig_name_init; $_sig_name_init = sub {
		1428	eval q{ # poor man's autoloading
		1429	undef $_sig_name_init;
		1430
		1431	if (_have_async_interrupt) {
		1432	*sig2num = \&Async::Interrupt::sig2num;
		1433	*sig2name = \&Async::Interrupt::sig2name;
		1434	} else {
		1435	require Config;
		1436
		1437	my %signame2num;
		1438	@signame2num{ split ' ', $Config::Config{sig_name} }
		1439	= split ' ', $Config::Config{sig_num};
		1440
		1441	my @signum2name;
		1442	@signum2name[values %signame2num] = keys %signame2num;
		1443
		1444	*sig2num = sub($) {
		1445	$_[0] > 0 ? shift : $signame2num{+shift}
		1446	};
		1447	*sig2name = sub ($) {
		1448	$_[0] > 0 ? $signum2name[+shift] : shift
		1449	};
		1450	}
		1451	};
		1452	die if $@;
		1453	};
		1454
		1455	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1456	sub sig2name($) { &$_sig_name_init; &sig2name }
1049		1457
1050	sub signal {	1458	sub signal {
		1459	eval q{ # poor man's autoloading {}
		1460	# probe for availability of Async::Interrupt
		1461	if (_have_async_interrupt) {
		1462	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
		1463
		1464	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1465	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
		1466
		1467	} else {
		1468	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1469
		1470	require Fcntl;
		1471
		1472	if (AnyEvent::WIN32) {
		1473	require AnyEvent::Util;
		1474
		1475	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1476	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1477	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1478	} else {
		1479	pipe $SIGPIPE_R, $SIGPIPE_W;
		1480	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1481	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1482
		1483	# not strictly required, as $^F is normally 2, but let's make sure...
		1484	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1485	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1486	}
		1487
		1488	$SIGPIPE_R
		1489	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1490
		1491	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
		1492	}
		1493
		1494	*signal = sub {
1051	my (undef, %arg) = @_;	1495	my (undef, %arg) = @_;
1052		1496
1053	my $signal = uc $arg{signal}	1497	my $signal = uc $arg{signal}
1054	or Carp::croak "required option 'signal' is missing";	1498	or Carp::croak "required option 'signal' is missing";
1055		1499
		1500	if ($HAVE_ASYNC_INTERRUPT) {
		1501	# async::interrupt
		1502
		1503	$signal = sig2num $signal;
1056	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1504	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1505
		1506	$SIG_ASY{$signal} ||= new Async::Interrupt
		1507	cb => sub { undef $SIG_EV{$signal} },
		1508	signal => $signal,
		1509	pipe => [$SIGPIPE_R->filenos],
		1510	pipe_autodrain => 0,
		1511	;
		1512
		1513	} else {
		1514	# pure perl
		1515
		1516	# AE::Util has been loaded in signal
		1517	$signal = sig2name $signal;
		1518	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1519
1057	$SIG{$signal} ||= sub {	1520	$SIG{$signal} ||= sub {
1058	$_->() for values %{ $SIG_CB{$signal} || {} };	1521	local $!;
		1522	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1523	undef $SIG_EV{$signal};
		1524	};
		1525
		1526	# can't do signal processing without introducing races in pure perl,
		1527	# so limit the signal latency.
		1528	_sig_add;
		1529	}
		1530
		1531	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1532	};
		1533
		1534	*AnyEvent::Base::signal::DESTROY = sub {
		1535	my ($signal, $cb) = @{$_[0]};
		1536
		1537	_sig_del;
		1538
		1539	delete $SIG_CB{$signal}{$cb};
		1540
		1541	$HAVE_ASYNC_INTERRUPT
		1542	? delete $SIG_ASY{$signal}
		1543	: # delete doesn't work with older perls - they then
		1544	# print weird messages, or just unconditionally exit
		1545	# instead of getting the default action.
		1546	undef $SIG{$signal}
		1547	unless keys %{ $SIG_CB{$signal} };
		1548	};
1059	};	1549	};
1060		1550	die if $@;
1061	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1551	&signal
1062	}
1063
1064	sub AnyEvent::Base::Signal::DESTROY {
1065	my ($signal, $cb) = @{$_[0]};
1066
1067	delete $SIG_CB{$signal}{$cb};
1068
1069	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1070	}	1552	}
1071		1553
1072	# default implementation for ->child	1554	# default implementation for ->child
1073		1555
1074	our %PID_CB;	1556	our %PID_CB;
1075	our $CHLD_W;	1557	our $CHLD_W;
1076	our $CHLD_DELAY_W;	1558	our $CHLD_DELAY_W;
1077	our $PID_IDLE;
1078	our $WNOHANG;	1559	our $WNOHANG;
1079		1560
1080	sub _child_wait {	1561	sub _emit_childstatus($$) {
1081	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1562	my (undef, $rpid, $rstatus) = @_;
		1563
		1564	$_->($rpid, $rstatus)
1082	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1565	for values %{ $PID_CB{$rpid} || {} },
1083	(values %{ $PID_CB{0} || {} });	1566	values %{ $PID_CB{0} || {} };
1084	}
1085
1086	undef $PID_IDLE;
1087	}	1567	}
1088		1568
1089	sub _sigchld {	1569	sub _sigchld {
1090	# make sure we deliver these changes "synchronous" with the event loop.	1570	my $pid;
1091	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {	1571
1092	undef $CHLD_DELAY_W;	1572	AnyEvent->_emit_childstatus ($pid, $?)
1093	&_child_wait;	1573	while ($pid = waitpid -1, $WNOHANG) > 0;
1094	});
1095	}	1574	}
1096		1575
1097	sub child {	1576	sub child {
1098	my (undef, %arg) = @_;	1577	my (undef, %arg) = @_;
1099		1578
1100	defined (my $pid = $arg{pid} + 0)	1579	defined (my $pid = $arg{pid} + 0)
1101	or Carp::croak "required option 'pid' is missing";	1580	or Carp::croak "required option 'pid' is missing";
1102		1581
1103	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1582	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1104		1583
1105	unless ($WNOHANG) {	1584	# WNOHANG is almost cetrainly 1 everywhere
		1585	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1586	? 1
1106	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1587	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1107	}
1108		1588
1109	unless ($CHLD_W) {	1589	unless ($CHLD_W) {
1110	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1590	$CHLD_W = AE::signal CHLD => \&_sigchld;
1111	# child could be a zombie already, so make at least one round	1591	# child could be a zombie already, so make at least one round
1112	&_sigchld;	1592	&_sigchld;
1113	}	1593	}
1114		1594
1115	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1595	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1116	}	1596	}
1117		1597
1118	sub AnyEvent::Base::Child::DESTROY {	1598	sub AnyEvent::Base::child::DESTROY {
1119	my ($pid, $cb) = @{$_[0]};	1599	my ($pid, $cb) = @{$_[0]};
1120		1600
1121	delete $PID_CB{$pid}{$cb};	1601	delete $PID_CB{$pid}{$cb};
1122	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1602	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1123		1603
1124	undef $CHLD_W unless keys %PID_CB;	1604	undef $CHLD_W unless keys %PID_CB;
1125	}	1605	}
1126		1606
		1607	# idle emulation is done by simply using a timer, regardless
		1608	# of whether the process is idle or not, and not letting
		1609	# the callback use more than 50% of the time.
		1610	sub idle {
		1611	my (undef, %arg) = @_;
		1612
		1613	my ($cb, $w, $rcb) = $arg{cb};
		1614
		1615	$rcb = sub {
		1616	if ($cb) {
		1617	$w = _time;
		1618	&$cb;
		1619	$w = _time - $w;
		1620
		1621	# never use more then 50% of the time for the idle watcher,
		1622	# within some limits
		1623	$w = 0.0001 if $w < 0.0001;
		1624	$w = 5 if $w > 5;
		1625
		1626	$w = AE::timer $w, 0, $rcb;
		1627	} else {
		1628	# clean up...
		1629	undef $w;
		1630	undef $rcb;
		1631	}
		1632	};
		1633
		1634	$w = AE::timer 0.05, 0, $rcb;
		1635
		1636	bless \\$cb, "AnyEvent::Base::idle"
		1637	}
		1638
		1639	sub AnyEvent::Base::idle::DESTROY {
		1640	undef $${$_[0]};
		1641	}
		1642
1127	package AnyEvent::CondVar;	1643	package AnyEvent::CondVar;
1128		1644
1129	our @ISA = AnyEvent::CondVar::Base::;	1645	our @ISA = AnyEvent::CondVar::Base::;
1130		1646
1131	package AnyEvent::CondVar::Base;	1647	package AnyEvent::CondVar::Base;
1132		1648
1133	use overload	1649	#use overload
1134	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1650	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1135	fallback => 1;	1651	# fallback => 1;
		1652
		1653	# save 300+ kilobytes by dirtily hardcoding overloading
		1654	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1655	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1656	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1657	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1658
		1659	our $WAITING;
1136		1660
1137	sub _send {	1661	sub _send {
1138	# nop	1662	# nop
1139	}	1663	}
1140		1664
…		…
1153	sub ready {	1677	sub ready {
1154	$_[0]{_ae_sent}	1678	$_[0]{_ae_sent}
1155	}	1679	}
1156		1680
1157	sub _wait {	1681	sub _wait {
		1682	$WAITING
		1683	and !$_[0]{_ae_sent}
		1684	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1685
		1686	local $WAITING = 1;
1158	AnyEvent->one_event while !$_[0]{_ae_sent};	1687	AnyEvent->one_event while !$_[0]{_ae_sent};
1159	}	1688	}
1160		1689
1161	sub recv {	1690	sub recv {
1162	$_[0]->_wait;	1691	$_[0]->_wait;
…		…
1164	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1693	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1165	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1694	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1166	}	1695	}
1167		1696
1168	sub cb {	1697	sub cb {
1169	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1698	my $cv = shift;
		1699
		1700	@_
		1701	and $cv->{_ae_cb} = shift
		1702	and $cv->{_ae_sent}
		1703	and (delete $cv->{_ae_cb})->($cv);
		1704
1170	$_[0]{_ae_cb}	1705	$cv->{_ae_cb}
1171	}	1706	}
1172		1707
1173	sub begin {	1708	sub begin {
1174	++$_[0]{_ae_counter};	1709	++$_[0]{_ae_counter};
1175	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1710	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1203	so on.	1738	so on.
1204		1739
1205	=head1 ENVIRONMENT VARIABLES	1740	=head1 ENVIRONMENT VARIABLES
1206		1741
1207	The following environment variables are used by this module or its	1742	The following environment variables are used by this module or its
1208	submodules:	1743	submodules.
		1744
		1745	Note that AnyEvent will remove I<all> environment variables starting with
		1746	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1747	enabled.
1209		1748
1210	=over 4	1749	=over 4
1211		1750
1212	=item C<PERL_ANYEVENT_VERBOSE>	1751	=item C<PERL_ANYEVENT_VERBOSE>
1213		1752
…		…
1220	C<PERL_ANYEVENT_MODEL>.	1759	C<PERL_ANYEVENT_MODEL>.
1221		1760
1222	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1761	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1223	model it chooses.	1762	model it chooses.
1224		1763
		1764	When set to C<8> or higher, then AnyEvent will report extra information on
		1765	which optional modules it loads and how it implements certain features.
		1766
1225	=item C<PERL_ANYEVENT_STRICT>	1767	=item C<PERL_ANYEVENT_STRICT>
1226		1768
1227	AnyEvent does not do much argument checking by default, as thorough	1769	AnyEvent does not do much argument checking by default, as thorough
1228	argument checking is very costly. Setting this variable to a true value	1770	argument checking is very costly. Setting this variable to a true value
1229	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1771	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1230	check the arguments passed to most method calls. If it finds any problems	1772	check the arguments passed to most method calls. If it finds any problems,
1231	it will croak.	1773	it will croak.
1232		1774
1233	In other words, enables "strict" mode.	1775	In other words, enables "strict" mode.
1234		1776
1235	Unlike C<use strict>, it is definitely recommended ot keep it off in	1777	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1236	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1778	>>, it is definitely recommended to keep it off in production. Keeping
1237	developing programs can be very useful, however.	1779	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1780	can be very useful, however.
1238		1781
1239	=item C<PERL_ANYEVENT_MODEL>	1782	=item C<PERL_ANYEVENT_MODEL>
1240		1783
1241	This can be used to specify the event model to be used by AnyEvent, before	1784	This can be used to specify the event model to be used by AnyEvent, before
1242	auto detection and -probing kicks in. It must be a string consisting	1785	auto detection and -probing kicks in. It must be a string consisting
…		…
1263	used, and preference will be given to protocols mentioned earlier in the	1806	used, and preference will be given to protocols mentioned earlier in the
1264	list.	1807	list.
1265		1808
1266	This variable can effectively be used for denial-of-service attacks	1809	This variable can effectively be used for denial-of-service attacks
1267	against local programs (e.g. when setuid), although the impact is likely	1810	against local programs (e.g. when setuid), although the impact is likely
1268	small, as the program has to handle connection errors already-	1811	small, as the program has to handle conenction and other failures anyways.
1269		1812
1270	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,	1813	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1271	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>	1814	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1272	- only support IPv4, never try to resolve or contact IPv6	1815	- only support IPv4, never try to resolve or contact IPv6
1273	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or	1816	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
…		…
1285		1828
1286	=item C<PERL_ANYEVENT_MAX_FORKS>	1829	=item C<PERL_ANYEVENT_MAX_FORKS>
1287		1830
1288	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1831	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1289	will create in parallel.	1832	will create in parallel.
		1833
		1834	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1835
		1836	The default value for the C<max_outstanding> parameter for the default DNS
		1837	resolver - this is the maximum number of parallel DNS requests that are
		1838	sent to the DNS server.
		1839
		1840	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1841
		1842	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1843	configuration) in the default resolver. When set to the empty string, no
		1844	default config will be used.
		1845
		1846	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1847
		1848	When neither C<ca_file> nor C<ca_path> was specified during
		1849	L<AnyEvent::TLS> context creation, and either of these environment
		1850	variables exist, they will be used to specify CA certificate locations
		1851	instead of a system-dependent default.
		1852
		1853	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1854
		1855	When these are set to C<1>, then the respective modules are not
		1856	loaded. Mostly good for testing AnyEvent itself.
1290		1857
1291	=back	1858	=back
1292		1859
1293	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1860	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1294		1861
…		…
1352	warn "read: $input\n"; # output what has been read	1919	warn "read: $input\n"; # output what has been read
1353	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1920	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1354	},	1921	},
1355	);	1922	);
1356		1923
1357	my $time_watcher; # can only be used once
1358
1359	sub new_timer {
1360	$timer = AnyEvent->timer (after => 1, cb => sub {	1924	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1361	warn "timeout\n"; # print 'timeout' about every second	1925	warn "timeout\n"; # print 'timeout' at most every second
1362	&new_timer; # and restart the time
1363	});	1926	});
1364	}
1365
1366	new_timer; # create first timer
1367		1927
1368	$cv->recv; # wait until user enters /^q/i	1928	$cv->recv; # wait until user enters /^q/i
1369		1929
1370	=head1 REAL-WORLD EXAMPLE	1930	=head1 REAL-WORLD EXAMPLE
1371		1931
…		…
1502	through AnyEvent. The benchmark creates a lot of timers (with a zero	2062	through AnyEvent. The benchmark creates a lot of timers (with a zero
1503	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2063	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1504	which it is), lets them fire exactly once and destroys them again.	2064	which it is), lets them fire exactly once and destroys them again.
1505		2065
1506	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2066	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1507	distribution.	2067	distribution. It uses the L<AE> interface, which makes a real difference
		2068	for the EV and Perl backends only.
1508		2069
1509	=head3 Explanation of the columns	2070	=head3 Explanation of the columns
1510		2071
1511	I<watcher> is the number of event watchers created/destroyed. Since	2072	I<watcher> is the number of event watchers created/destroyed. Since
1512	different event models feature vastly different performances, each event	2073	different event models feature vastly different performances, each event
…		…
1533	watcher.	2094	watcher.
1534		2095
1535	=head3 Results	2096	=head3 Results
1536		2097
1537	name watchers bytes create invoke destroy comment	2098	name watchers bytes create invoke destroy comment
1538	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	2099	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1539	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	2100	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1540	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	2101	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1541	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	2102	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1542	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	2103	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1543	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	2104	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2105	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2106	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1544	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	2107	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1545	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	2108	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1546	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	2109	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1547	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	2110	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1548		2111
1549	=head3 Discussion	2112	=head3 Discussion
1550		2113
1551	The benchmark does I<not> measure scalability of the event loop very	2114	The benchmark does I<not> measure scalability of the event loop very
1552	well. For example, a select-based event loop (such as the pure perl one)	2115	well. For example, a select-based event loop (such as the pure perl one)
…		…
1564	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2127	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1565	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2128	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1566	cycles with POE.	2129	cycles with POE.
1567		2130
1568	C<EV> is the sole leader regarding speed and memory use, which are both	2131	C<EV> is the sole leader regarding speed and memory use, which are both
1569	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2132	maximal/minimal, respectively. When using the L<AE> API there is zero
		2133	overhead (when going through the AnyEvent API create is about 5-6 times
		2134	slower, with other times being equal, so still uses far less memory than
1570	far less memory than any other event loop and is still faster than Event	2135	any other event loop and is still faster than Event natively).
1571	natively.
1572		2136
1573	The pure perl implementation is hit in a few sweet spots (both the	2137	The pure perl implementation is hit in a few sweet spots (both the
1574	constant timeout and the use of a single fd hit optimisations in the perl	2138	constant timeout and the use of a single fd hit optimisations in the perl
1575	interpreter and the backend itself). Nevertheless this shows that it	2139	interpreter and the backend itself). Nevertheless this shows that it
1576	adds very little overhead in itself. Like any select-based backend its	2140	adds very little overhead in itself. Like any select-based backend its
1577	performance becomes really bad with lots of file descriptors (and few of	2141	performance becomes really bad with lots of file descriptors (and few of
1578	them active), of course, but this was not subject of this benchmark.	2142	them active), of course, but this was not subject of this benchmark.
1579		2143
1580	The C<Event> module has a relatively high setup and callback invocation	2144	The C<Event> module has a relatively high setup and callback invocation
1581	cost, but overall scores in on the third place.	2145	cost, but overall scores in on the third place.
		2146
		2147	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2148	when using its pure perl backend.
1582		2149
1583	C<Glib>'s memory usage is quite a bit higher, but it features a	2150	C<Glib>'s memory usage is quite a bit higher, but it features a
1584	faster callback invocation and overall ends up in the same class as	2151	faster callback invocation and overall ends up in the same class as
1585	C<Event>. However, Glib scales extremely badly, doubling the number of	2152	C<Event>. However, Glib scales extremely badly, doubling the number of
1586	watchers increases the processing time by more than a factor of four,	2153	watchers increases the processing time by more than a factor of four,
…		…
1647	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2214	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1648	(1%) are active. This mirrors the activity of large servers with many	2215	(1%) are active. This mirrors the activity of large servers with many
1649	connections, most of which are idle at any one point in time.	2216	connections, most of which are idle at any one point in time.
1650		2217
1651	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2218	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1652	distribution.	2219	distribution. It uses the L<AE> interface, which makes a real difference
		2220	for the EV and Perl backends only.
1653		2221
1654	=head3 Explanation of the columns	2222	=head3 Explanation of the columns
1655		2223
1656	I<sockets> is the number of sockets, and twice the number of "servers" (as	2224	I<sockets> is the number of sockets, and twice the number of "servers" (as
1657	each server has a read and write socket end).	2225	each server has a read and write socket end).
…		…
1664	it to another server. This includes deleting the old timeout and creating	2232	it to another server. This includes deleting the old timeout and creating
1665	a new one that moves the timeout into the future.	2233	a new one that moves the timeout into the future.
1666		2234
1667	=head3 Results	2235	=head3 Results
1668		2236
1669	name sockets create request	2237	name sockets create request
1670	EV 20000 69.01 11.16	2238	EV 20000 62.66 7.99
1671	Perl 20000 73.32 35.87	2239	Perl 20000 68.32 32.64
1672	Event 20000 212.62 257.32	2240	IOAsync 20000 174.06 101.15 epoll
1673	Glib 20000 651.16 1896.30	2241	IOAsync 20000 174.67 610.84 poll
		2242	Event 20000 202.69 242.91
		2243	Glib 20000 557.01 1689.52
1674	POE 20000 349.67 12317.24 uses POE::Loop::Event	2244	POE 20000 341.54 12086.32 uses POE::Loop::Event
1675		2245
1676	=head3 Discussion	2246	=head3 Discussion
1677		2247
1678	This benchmark I<does> measure scalability and overall performance of the	2248	This benchmark I<does> measure scalability and overall performance of the
1679	particular event loop.	2249	particular event loop.
…		…
1681	EV is again fastest. Since it is using epoll on my system, the setup time	2251	EV is again fastest. Since it is using epoll on my system, the setup time
1682	is relatively high, though.	2252	is relatively high, though.
1683		2253
1684	Perl surprisingly comes second. It is much faster than the C-based event	2254	Perl surprisingly comes second. It is much faster than the C-based event
1685	loops Event and Glib.	2255	loops Event and Glib.
		2256
		2257	IO::Async performs very well when using its epoll backend, and still quite
		2258	good compared to Glib when using its pure perl backend.
1686		2259
1687	Event suffers from high setup time as well (look at its code and you will	2260	Event suffers from high setup time as well (look at its code and you will
1688	understand why). Callback invocation also has a high overhead compared to	2261	understand why). Callback invocation also has a high overhead compared to
1689	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2262	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1690	uses select or poll in basically all documented configurations.	2263	uses select or poll in basically all documented configurations.
…		…
1753	=item * C-based event loops perform very well with small number of	2326	=item * C-based event loops perform very well with small number of
1754	watchers, as the management overhead dominates.	2327	watchers, as the management overhead dominates.
1755		2328
1756	=back	2329	=back
1757		2330
		2331	=head2 THE IO::Lambda BENCHMARK
		2332
		2333	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2334	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2335	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2336	shouldn't come as a surprise to anybody). As such, the benchmark is
		2337	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2338	very optimal. But how would AnyEvent compare when used without the extra
		2339	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2340
		2341	The benchmark itself creates an echo-server, and then, for 500 times,
		2342	connects to the echo server, sends a line, waits for the reply, and then
		2343	creates the next connection. This is a rather bad benchmark, as it doesn't
		2344	test the efficiency of the framework or much non-blocking I/O, but it is a
		2345	benchmark nevertheless.
		2346
		2347	name runtime
		2348	Lambda/select 0.330 sec
		2349	+ optimized 0.122 sec
		2350	Lambda/AnyEvent 0.327 sec
		2351	+ optimized 0.138 sec
		2352	Raw sockets/select 0.077 sec
		2353	POE/select, components 0.662 sec
		2354	POE/select, raw sockets 0.226 sec
		2355	POE/select, optimized 0.404 sec
		2356
		2357	AnyEvent/select/nb 0.085 sec
		2358	AnyEvent/EV/nb 0.068 sec
		2359	+state machine 0.134 sec
		2360
		2361	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2362	benchmarks actually make blocking connects and use 100% blocking I/O,
		2363	defeating the purpose of an event-based solution. All of the newly
		2364	written AnyEvent benchmarks use 100% non-blocking connects (using
		2365	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2366	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2367	generally require a lot more bookkeeping and event handling than blocking
		2368	connects (which involve a single syscall only).
		2369
		2370	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2371	offers similar expressive power as POE and IO::Lambda, using conventional
		2372	Perl syntax. This means that both the echo server and the client are 100%
		2373	non-blocking, further placing it at a disadvantage.
		2374
		2375	As you can see, the AnyEvent + EV combination even beats the
		2376	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2377	backend easily beats IO::Lambda and POE.
		2378
		2379	And even the 100% non-blocking version written using the high-level (and
		2380	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2381	higher level ("unoptimised") abstractions by a large margin, even though
		2382	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
		2383
		2384	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2385	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2386	part of the IO::Lambda distribution and were used without any changes.
		2387
1758		2388
1759	=head1 SIGNALS	2389	=head1 SIGNALS
1760		2390
1761	AnyEvent currently installs handlers for these signals:	2391	AnyEvent currently installs handlers for these signals:
1762		2392
…		…
1765	=item SIGCHLD	2395	=item SIGCHLD
1766		2396
1767	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2397	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1768	emulation for event loops that do not support them natively. Also, some	2398	emulation for event loops that do not support them natively. Also, some
1769	event loops install a similar handler.	2399	event loops install a similar handler.
		2400
		2401	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2402	AnyEvent will reset it to default, to avoid losing child exit statuses.
1770		2403
1771	=item SIGPIPE	2404	=item SIGPIPE
1772		2405
1773	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2406	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1774	when AnyEvent gets loaded.	2407	when AnyEvent gets loaded.
…		…
1786		2419
1787	=back	2420	=back
1788		2421
1789	=cut	2422	=cut
1790		2423
		2424	undef $SIG{CHLD}
		2425	if $SIG{CHLD} eq 'IGNORE';
		2426
1791	$SIG{PIPE} = sub { }	2427	$SIG{PIPE} = sub { }
1792	unless defined $SIG{PIPE};	2428	unless defined $SIG{PIPE};
		2429
		2430	=head1 RECOMMENDED/OPTIONAL MODULES
		2431
		2432	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2433	it's built-in modules) are required to use it.
		2434
		2435	That does not mean that AnyEvent won't take advantage of some additional
		2436	modules if they are installed.
		2437
		2438	This section epxlains which additional modules will be used, and how they
		2439	affect AnyEvent's operetion.
		2440
		2441	=over 4
		2442
		2443	=item L<Async::Interrupt>
		2444
		2445	This slightly arcane module is used to implement fast signal handling: To
		2446	my knowledge, there is no way to do completely race-free and quick
		2447	signal handling in pure perl. To ensure that signals still get
		2448	delivered, AnyEvent will start an interval timer to wake up perl (and
		2449	catch the signals) with some delay (default is 10 seconds, look for
		2450	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2451
		2452	If this module is available, then it will be used to implement signal
		2453	catching, which means that signals will not be delayed, and the event loop
		2454	will not be interrupted regularly, which is more efficient (And good for
		2455	battery life on laptops).
		2456
		2457	This affects not just the pure-perl event loop, but also other event loops
		2458	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2459
		2460	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2461	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2462	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2463	does nothing for those backends.
		2464
		2465	=item L<EV>
		2466
		2467	This module isn't really "optional", as it is simply one of the backend
		2468	event loops that AnyEvent can use. However, it is simply the best event
		2469	loop available in terms of features, speed and stability: It supports
		2470	the AnyEvent API optimally, implements all the watcher types in XS, does
		2471	automatic timer adjustments even when no monotonic clock is available,
		2472	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2473	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2474	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2475
		2476	=item L<Guard>
		2477
		2478	The guard module, when used, will be used to implement
		2479	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2480	lot less memory), but otherwise doesn't affect guard operation much. It is
		2481	purely used for performance.
		2482
		2483	=item L<JSON> and L<JSON::XS>
		2484
		2485	One of these modules is required when you want to read or write JSON data
		2486	via L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2487	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2488
		2489	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2490	installed.
		2491
		2492	=item L<Net::SSLeay>
		2493
		2494	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2495	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2496	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2497
		2498	=item L<Time::HiRes>
		2499
		2500	This module is part of perl since release 5.008. It will be used when the
		2501	chosen event library does not come with a timing source on it's own. The
		2502	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2503	try to use a monotonic clock for timing stability.
		2504
		2505	=back
1793		2506
1794		2507
1795	=head1 FORK	2508	=head1 FORK
1796		2509
1797	Most event libraries are not fork-safe. The ones who are usually are	2510	Most event libraries are not fork-safe. The ones who are usually are
1798	because they rely on inefficient but fork-safe C<select> or C<poll>	2511	because they rely on inefficient but fork-safe C<select> or C<poll>
1799	calls. Only L<EV> is fully fork-aware.	2512	calls. Only L<EV> is fully fork-aware.
1800		2513
1801	If you have to fork, you must either do so I<before> creating your first	2514	If you have to fork, you must either do so I<before> creating your first
1802	watcher OR you must not use AnyEvent at all in the child.	2515	watcher OR you must not use AnyEvent at all in the child OR you must do
		2516	something completely out of the scope of AnyEvent.
1803		2517
1804		2518
1805	=head1 SECURITY CONSIDERATIONS	2519	=head1 SECURITY CONSIDERATIONS
1806		2520
1807	AnyEvent can be forced to load any event model via	2521	AnyEvent can be forced to load any event model via
…		…
1819	use AnyEvent;	2533	use AnyEvent;
1820		2534
1821	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2535	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1822	be used to probe what backend is used and gain other information (which is	2536	be used to probe what backend is used and gain other information (which is
1823	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2537	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1824	$ENV{PERL_ANYEGENT_STRICT}.	2538	$ENV{PERL_ANYEVENT_STRICT}.
		2539
		2540	Note that AnyEvent will remove I<all> environment variables starting with
		2541	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2542	enabled.
1825		2543
1826		2544
1827	=head1 BUGS	2545	=head1 BUGS
1828		2546
1829	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2547	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1830	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2548	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1831	and check wether the leaks still show up. (Perl 5.10.0 has other annoying	2549	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1832	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as	2550	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1833	pronounced).	2551	pronounced).
1834		2552
1835		2553
1836	=head1 SEE ALSO	2554	=head1 SEE ALSO
1837		2555
…		…
1841	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2559	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1842		2560
1843	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2561	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1844	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2562	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1845	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2563	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1846	L<AnyEvent::Impl::POE>.	2564	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1847		2565
1848	Non-blocking file handles, sockets, TCP clients and	2566	Non-blocking file handles, sockets, TCP clients and
1849	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2567	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1850		2568
1851	Asynchronous DNS: L<AnyEvent::DNS>.	2569	Asynchronous DNS: L<AnyEvent::DNS>.
1852		2570
1853	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2571	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2572	L<Coro::Event>,
1854		2573
1855	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2574	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2575	L<AnyEvent::HTTP>.
1856		2576
1857		2577
1858	=head1 AUTHOR	2578	=head1 AUTHOR
1859		2579
1860	Marc Lehmann <schmorp@schmorp.de>	2580	Marc Lehmann <schmorp@schmorp.de>

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