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Revision 1.198 by root, Thu Mar 26 20:17:44 2009 UTC vs.
Revision 1.309 by root, Sat Dec 26 08:59:35 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?
…		…
165	my variables are only visible after the statement in which they are	181	my variables are only visible after the statement in which they are
166	declared.	182	declared.
167		183
168	=head2 I/O WATCHERS	184	=head2 I/O WATCHERS
169		185
		186	$w = AnyEvent->io (
		187	fh => <filehandle_or_fileno>,
		188	poll => <"r" or "w">,
		189	cb => <callback>,
		190	);
		191
170	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	192	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
171	with the following mandatory key-value pairs as arguments:	193	with the following mandatory key-value pairs as arguments:
172		194
173	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events	195	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
174	(AnyEvent might or might not keep a reference to this file handle). C<poll>	196	for events (AnyEvent might or might not keep a reference to this file
		197	handle). Note that only file handles pointing to things for which
		198	non-blocking operation makes sense are allowed. This includes sockets,
		199	most character devices, pipes, fifos and so on, but not for example files
		200	or block devices.
		201
175	must be a string that is either C<r> or C<w>, which creates a watcher	202	C<poll> must be a string that is either C<r> or C<w>, which creates a
176	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the	203	watcher waiting for "r"eadable or "w"ritable events, respectively.
		204
177	callback to invoke each time the file handle becomes ready.	205	C<cb> is the callback to invoke each time the file handle becomes ready.
178		206
179	Although the callback might get passed parameters, their value and	207	Although the callback might get passed parameters, their value and
180	presence is undefined and you cannot rely on them. Portable AnyEvent	208	presence is undefined and you cannot rely on them. Portable AnyEvent
181	callbacks cannot use arguments passed to I/O watcher callbacks.	209	callbacks cannot use arguments passed to I/O watcher callbacks.
182		210
…		…
197	undef $w;	225	undef $w;
198	});	226	});
199		227
200	=head2 TIME WATCHERS	228	=head2 TIME WATCHERS
201		229
		230	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		231
		232	$w = AnyEvent->timer (
		233	after => <fractional_seconds>,
		234	interval => <fractional_seconds>,
		235	cb => <callback>,
		236	);
		237
202	You can create a time watcher by calling the C<< AnyEvent->timer >>	238	You can create a time watcher by calling the C<< AnyEvent->timer >>
203	method with the following mandatory arguments:	239	method with the following mandatory arguments:
204		240
205	C<after> specifies after how many seconds (fractional values are	241	C<after> specifies after how many seconds (fractional values are
206	supported) the callback should be invoked. C<cb> is the callback to invoke	242	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
314	In either case, if you care (and in most cases, you don't), then you	350	In either case, if you care (and in most cases, you don't), then you
315	can get whatever behaviour you want with any event loop, by taking the	351	can get whatever behaviour you want with any event loop, by taking the
316	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	352	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
317	account.	353	account.
318		354
		355	=item AnyEvent->now_update
		356
		357	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		358	the current time for each loop iteration (see the discussion of L<<
		359	AnyEvent->now >>, above).
		360
		361	When a callback runs for a long time (or when the process sleeps), then
		362	this "current" time will differ substantially from the real time, which
		363	might affect timers and time-outs.
		364
		365	When this is the case, you can call this method, which will update the
		366	event loop's idea of "current time".
		367
		368	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		369	when mod_perl executes the script, then the event loop will have the wrong
		370	idea about the "current time" (being potentially far in the past, when the
		371	script ran the last time). In that case you should arrange a call to C<<
		372	AnyEvent->now_update >> each time the web server process wakes up again
		373	(e.g. at the start of your script, or in a handler).
		374
		375	Note that updating the time I<might> cause some events to be handled.
		376
319	=back	377	=back
320		378
321	=head2 SIGNAL WATCHERS	379	=head2 SIGNAL WATCHERS
		380
		381	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
322		382
323	You can watch for signals using a signal watcher, C<signal> is the signal	383	You can watch for signals using a signal watcher, C<signal> is the signal
324	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	384	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
325	callback to be invoked whenever a signal occurs.	385	callback to be invoked whenever a signal occurs.
326		386
…		…
332	invocation, and callback invocation will be synchronous. Synchronous means	392	invocation, and callback invocation will be synchronous. Synchronous means
333	that it might take a while until the signal gets handled by the process,	393	that it might take a while until the signal gets handled by the process,
334	but it is guaranteed not to interrupt any other callbacks.	394	but it is guaranteed not to interrupt any other callbacks.
335		395
336	The main advantage of using these watchers is that you can share a signal	396	The main advantage of using these watchers is that you can share a signal
337	between multiple watchers.	397	between multiple watchers, and AnyEvent will ensure that signals will not
		398	interrupt your program at bad times.
338		399
339	This watcher might use C<%SIG>, so programs overwriting those signals	400	This watcher might use C<%SIG> (depending on the event loop used),
340	directly will likely not work correctly.	401	so programs overwriting those signals directly will likely not work
		402	correctly.
341		403
342	Example: exit on SIGINT	404	Example: exit on SIGINT
343		405
344	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	406	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
345		407
		408	=head3 Restart Behaviour
		409
		410	While restart behaviour is up to the event loop implementation, most will
		411	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		412	pure perl implementation).
		413
		414	=head3 Safe/Unsafe Signals
		415
		416	Perl signals can be either "safe" (synchronous to opcode handling) or
		417	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		418	latter might corrupt your memory.
		419
		420	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		421	i.e. they will not interrupt your running perl program but will only be
		422	called as part of the normal event handling (just like timer, I/O etc.
		423	callbacks, too).
		424
		425	=head3 Signal Races, Delays and Workarounds
		426
		427	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		428	callbacks to signals in a generic way, which is a pity, as you cannot
		429	do race-free signal handling in perl, requiring C libraries for
		430	this. AnyEvent will try to do it's best, which means in some cases,
		431	signals will be delayed. The maximum time a signal might be delayed is
		432	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		433	variable can be changed only before the first signal watcher is created,
		434	and should be left alone otherwise. This variable determines how often
		435	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		436	will cause fewer spurious wake-ups, which is better for power and CPU
		437	saving.
		438
		439	All these problems can be avoided by installing the optional
		440	L<Async::Interrupt> module, which works with most event loops. It will not
		441	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		442	(and not with L<POE> currently, as POE does it's own workaround with
		443	one-second latency). For those, you just have to suffer the delays.
		444
346	=head2 CHILD PROCESS WATCHERS	445	=head2 CHILD PROCESS WATCHERS
347		446
		447	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		448
348	You can also watch on a child process exit and catch its exit status.	449	You can also watch on a child process exit and catch its exit status.
349		450
350	The child process is specified by the C<pid> argument (if set to C<0>, it	451	The child process is specified by the C<pid> argument (one some backends,
351	watches for any child process exit). The watcher will triggered only when	452	using C<0> watches for any child process exit, on others this will
352	the child process has finished and an exit status is available, not on	453	croak). The watcher will be triggered only when the child process has
353	any trace events (stopped/continued).	454	finished and an exit status is available, not on any trace events
		455	(stopped/continued).
354		456
355	The callback will be called with the pid and exit status (as returned by	457	The callback will be called with the pid and exit status (as returned by
356	waitpid), so unlike other watcher types, you I<can> rely on child watcher	458	waitpid), so unlike other watcher types, you I<can> rely on child watcher
357	callback arguments.	459	callback arguments.
358		460
…		…
363		465
364	There is a slight catch to child watchers, however: you usually start them	466	There is a slight catch to child watchers, however: you usually start them
365	I<after> the child process was created, and this means the process could	467	I<after> the child process was created, and this means the process could
366	have exited already (and no SIGCHLD will be sent anymore).	468	have exited already (and no SIGCHLD will be sent anymore).
367		469
368	Not all event models handle this correctly (POE doesn't), but even for	470	Not all event models handle this correctly (neither POE nor IO::Async do,
		471	see their AnyEvent::Impl manpages for details), but even for event models
369	event models that I<do> handle this correctly, they usually need to be	472	that I<do> handle this correctly, they usually need to be loaded before
370	loaded before the process exits (i.e. before you fork in the first place).	473	the process exits (i.e. before you fork in the first place). AnyEvent's
		474	pure perl event loop handles all cases correctly regardless of when you
		475	start the watcher.
371		476
372	This means you cannot create a child watcher as the very first thing in an	477	This means you cannot create a child watcher as the very first
373	AnyEvent program, you I<have> to create at least one watcher before you	478	thing in an AnyEvent program, you I<have> to create at least one
374	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	479	watcher before you C<fork> the child (alternatively, you can call
		480	C<AnyEvent::detect>).
		481
		482	As most event loops do not support waiting for child events, they will be
		483	emulated by AnyEvent in most cases, in which the latency and race problems
		484	mentioned in the description of signal watchers apply.
375		485
376	Example: fork a process and wait for it	486	Example: fork a process and wait for it
377		487
378	my $done = AnyEvent->condvar;	488	my $done = AnyEvent->condvar;
379		489
…		…
389	);	499	);
390		500
391	# do something else, then wait for process exit	501	# do something else, then wait for process exit
392	$done->recv;	502	$done->recv;
393		503
		504	=head2 IDLE WATCHERS
		505
		506	$w = AnyEvent->idle (cb => <callback>);
		507
		508	Repeatedly invoke the callback after the process becomes idle, until
		509	either the watcher is destroyed or new events have been detected.
		510
		511	Idle watchers are useful when there is a need to do something, but it
		512	is not so important (or wise) to do it instantly. The callback will be
		513	invoked only when there is "nothing better to do", which is usually
		514	defined as "all outstanding events have been handled and no new events
		515	have been detected". That means that idle watchers ideally get invoked
		516	when the event loop has just polled for new events but none have been
		517	detected. Instead of blocking to wait for more events, the idle watchers
		518	will be invoked.
		519
		520	Unfortunately, most event loops do not really support idle watchers (only
		521	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		522	will simply call the callback "from time to time".
		523
		524	Example: read lines from STDIN, but only process them when the
		525	program is otherwise idle:
		526
		527	my @lines; # read data
		528	my $idle_w;
		529	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		530	push @lines, scalar <STDIN>;
		531
		532	# start an idle watcher, if not already done
		533	$idle_w ||= AnyEvent->idle (cb => sub {
		534	# handle only one line, when there are lines left
		535	if (my $line = shift @lines) {
		536	print "handled when idle: $line";
		537	} else {
		538	# otherwise disable the idle watcher again
		539	undef $idle_w;
		540	}
		541	});
		542	});
		543
394	=head2 CONDITION VARIABLES	544	=head2 CONDITION VARIABLES
		545
		546	$cv = AnyEvent->condvar;
		547
		548	$cv->send (<list>);
		549	my @res = $cv->recv;
395		550
396	If you are familiar with some event loops you will know that all of them	551	If you are familiar with some event loops you will know that all of them
397	require you to run some blocking "loop", "run" or similar function that	552	require you to run some blocking "loop", "run" or similar function that
398	will actively watch for new events and call your callbacks.	553	will actively watch for new events and call your callbacks.
399		554
400	AnyEvent is different, it expects somebody else to run the event loop and	555	AnyEvent is slightly different: it expects somebody else to run the event
401	will only block when necessary (usually when told by the user).	556	loop and will only block when necessary (usually when told by the user).
402		557
403	The instrument to do that is called a "condition variable", so called	558	The instrument to do that is called a "condition variable", so called
404	because they represent a condition that must become true.	559	because they represent a condition that must become true.
405		560
		561	Now is probably a good time to look at the examples further below.
		562
406	Condition variables can be created by calling the C<< AnyEvent->condvar	563	Condition variables can be created by calling the C<< AnyEvent->condvar
407	>> method, usually without arguments. The only argument pair allowed is	564	>> method, usually without arguments. The only argument pair allowed is
408
409	C<cb>, which specifies a callback to be called when the condition variable	565	C<cb>, which specifies a callback to be called when the condition variable
410	becomes true, with the condition variable as the first argument (but not	566	becomes true, with the condition variable as the first argument (but not
411	the results).	567	the results).
412		568
413	After creation, the condition variable is "false" until it becomes "true"	569	After creation, the condition variable is "false" until it becomes "true"
…		…
418	Condition variables are similar to callbacks, except that you can	574	Condition variables are similar to callbacks, except that you can
419	optionally wait for them. They can also be called merge points - points	575	optionally wait for them. They can also be called merge points - points
420	in time where multiple outstanding events have been processed. And yet	576	in time where multiple outstanding events have been processed. And yet
421	another way to call them is transactions - each condition variable can be	577	another way to call them is transactions - each condition variable can be
422	used to represent a transaction, which finishes at some point and delivers	578	used to represent a transaction, which finishes at some point and delivers
423	a result.	579	a result. And yet some people know them as "futures" - a promise to
		580	compute/deliver something that you can wait for.
424		581
425	Condition variables are very useful to signal that something has finished,	582	Condition variables are very useful to signal that something has finished,
426	for example, if you write a module that does asynchronous http requests,	583	for example, if you write a module that does asynchronous http requests,
427	then a condition variable would be the ideal candidate to signal the	584	then a condition variable would be the ideal candidate to signal the
428	availability of results. The user can either act when the callback is	585	availability of results. The user can either act when the callback is
…		…
462	after => 1,	619	after => 1,
463	cb => sub { $result_ready->send },	620	cb => sub { $result_ready->send },
464	);	621	);
465		622
466	# this "blocks" (while handling events) till the callback	623	# this "blocks" (while handling events) till the callback
467	# calls send	624	# calls ->send
468	$result_ready->recv;	625	$result_ready->recv;
469		626
470	Example: wait for a timer, but take advantage of the fact that	627	Example: wait for a timer, but take advantage of the fact that condition
471	condition variables are also code references.	628	variables are also callable directly.
472		629
473	my $done = AnyEvent->condvar;	630	my $done = AnyEvent->condvar;
474	my $delay = AnyEvent->timer (after => 5, cb => $done);	631	my $delay = AnyEvent->timer (after => 5, cb => $done);
475	$done->recv;	632	$done->recv;
476		633
…		…
482		639
483	...	640	...
484		641
485	my @info = $couchdb->info->recv;	642	my @info = $couchdb->info->recv;
486		643
487	And this is how you would just ste a callback to be called whenever the	644	And this is how you would just set a callback to be called whenever the
488	results are available:	645	results are available:
489		646
490	$couchdb->info->cb (sub {	647	$couchdb->info->cb (sub {
491	my @info = $_[0]->recv;	648	my @info = $_[0]->recv;
492	});	649	});
…		…
510	immediately from within send.	667	immediately from within send.
511		668
512	Any arguments passed to the C<send> call will be returned by all	669	Any arguments passed to the C<send> call will be returned by all
513	future C<< ->recv >> calls.	670	future C<< ->recv >> calls.
514		671
515	Condition variables are overloaded so one can call them directly	672	Condition variables are overloaded so one can call them directly (as if
516	(as a code reference). Calling them directly is the same as calling	673	they were a code reference). Calling them directly is the same as calling
517	C<send>. Note, however, that many C-based event loops do not handle	674	C<send>.
518	overloading, so as tempting as it may be, passing a condition variable
519	instead of a callback does not work. Both the pure perl and EV loops
520	support overloading, however, as well as all functions that use perl to
521	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
522	example).
523		675
524	=item $cv->croak ($error)	676	=item $cv->croak ($error)
525		677
526	Similar to send, but causes all call's to C<< ->recv >> to invoke	678	Similar to send, but causes all call's to C<< ->recv >> to invoke
527	C<Carp::croak> with the given error message/object/scalar.	679	C<Carp::croak> with the given error message/object/scalar.
528		680
529	This can be used to signal any errors to the condition variable	681	This can be used to signal any errors to the condition variable
530	user/consumer.	682	user/consumer. Doing it this way instead of calling C<croak> directly
		683	delays the error detetcion, but has the overwhelmign advantage that it
		684	diagnoses the error at the place where the result is expected, and not
		685	deep in some event clalback without connection to the actual code causing
		686	the problem.
531		687
532	=item $cv->begin ([group callback])	688	=item $cv->begin ([group callback])
533		689
534	=item $cv->end	690	=item $cv->end
535
536	These two methods are EXPERIMENTAL and MIGHT CHANGE.
537		691
538	These two methods can be used to combine many transactions/events into	692	These two methods can be used to combine many transactions/events into
539	one. For example, a function that pings many hosts in parallel might want	693	one. For example, a function that pings many hosts in parallel might want
540	to use a condition variable for the whole process.	694	to use a condition variable for the whole process.
541		695
542	Every call to C<< ->begin >> will increment a counter, and every call to	696	Every call to C<< ->begin >> will increment a counter, and every call to
543	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	697	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
544	>>, the (last) callback passed to C<begin> will be executed. That callback	698	>>, the (last) callback passed to C<begin> will be executed, passing the
545	is I<supposed> to call C<< ->send >>, but that is not required. If no	699	condvar as first argument. That callback is I<supposed> to call C<< ->send
546	callback was set, C<send> will be called without any arguments.	700	>>, but that is not required. If no group callback was set, C<send> will
		701	be called without any arguments.
547		702
548	Let's clarify this with the ping example:	703	You can think of C<< $cv->send >> giving you an OR condition (one call
		704	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		705	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		706
		707	Let's start with a simple example: you have two I/O watchers (for example,
		708	STDOUT and STDERR for a program), and you want to wait for both streams to
		709	close before activating a condvar:
549		710
550	my $cv = AnyEvent->condvar;	711	my $cv = AnyEvent->condvar;
551		712
		713	$cv->begin; # first watcher
		714	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		715	defined sysread $fh1, my $buf, 4096
		716	or $cv->end;
		717	});
		718
		719	$cv->begin; # second watcher
		720	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		721	defined sysread $fh2, my $buf, 4096
		722	or $cv->end;
		723	});
		724
		725	$cv->recv;
		726
		727	This works because for every event source (EOF on file handle), there is
		728	one call to C<begin>, so the condvar waits for all calls to C<end> before
		729	sending.
		730
		731	The ping example mentioned above is slightly more complicated, as the
		732	there are results to be passwd back, and the number of tasks that are
		733	begung can potentially be zero:
		734
		735	my $cv = AnyEvent->condvar;
		736
552	my %result;	737	my %result;
553	$cv->begin (sub { $cv->send (\%result) });	738	$cv->begin (sub { shift->send (\%result) });
554		739
555	for my $host (@list_of_hosts) {	740	for my $host (@list_of_hosts) {
556	$cv->begin;	741	$cv->begin;
557	ping_host_then_call_callback $host, sub {	742	ping_host_then_call_callback $host, sub {
558	$result{$host} = ...;	743	$result{$host} = ...;
…		…
573	loop, which serves two important purposes: first, it sets the callback	758	loop, which serves two important purposes: first, it sets the callback
574	to be called once the counter reaches C<0>, and second, it ensures that	759	to be called once the counter reaches C<0>, and second, it ensures that
575	C<send> is called even when C<no> hosts are being pinged (the loop	760	C<send> is called even when C<no> hosts are being pinged (the loop
576	doesn't execute once).	761	doesn't execute once).
577		762
578	This is the general pattern when you "fan out" into multiple subrequests:	763	This is the general pattern when you "fan out" into multiple (but
579	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	764	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
580	is called at least once, and then, for each subrequest you start, call	765	the callback and ensure C<end> is called at least once, and then, for each
581	C<begin> and for each subrequest you finish, call C<end>.	766	subrequest you start, call C<begin> and for each subrequest you finish,
		767	call C<end>.
582		768
583	=back	769	=back
584		770
585	=head3 METHODS FOR CONSUMERS	771	=head3 METHODS FOR CONSUMERS
586		772
…		…
602	function will call C<croak>.	788	function will call C<croak>.
603		789
604	In list context, all parameters passed to C<send> will be returned,	790	In list context, all parameters passed to C<send> will be returned,
605	in scalar context only the first one will be returned.	791	in scalar context only the first one will be returned.
606		792
		793	Note that doing a blocking wait in a callback is not supported by any
		794	event loop, that is, recursive invocation of a blocking C<< ->recv
		795	>> is not allowed, and the C<recv> call will C<croak> if such a
		796	condition is detected. This condition can be slightly loosened by using
		797	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		798	any thread that doesn't run the event loop itself.
		799
607	Not all event models support a blocking wait - some die in that case	800	Not all event models support a blocking wait - some die in that case
608	(programs might want to do that to stay interactive), so I<if you are	801	(programs might want to do that to stay interactive), so I<if you are
609	using this from a module, never require a blocking wait>, but let the	802	using this from a module, never require a blocking wait>. Instead, let the
610	caller decide whether the call will block or not (for example, by coupling	803	caller decide whether the call will block or not (for example, by coupling
611	condition variables with some kind of request results and supporting	804	condition variables with some kind of request results and supporting
612	callbacks so the caller knows that getting the result will not block,	805	callbacks so the caller knows that getting the result will not block,
613	while still supporting blocking waits if the caller so desires).	806	while still supporting blocking waits if the caller so desires).
614		807
615	Another reason I<never> to C<< ->recv >> in a module is that you cannot
616	sensibly have two C<< ->recv >>'s in parallel, as that would require
617	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
618	can supply.
619
620	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
621	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
622	versions and also integrates coroutines into AnyEvent, making blocking
623	C<< ->recv >> calls perfectly safe as long as they are done from another
624	coroutine (one that doesn't run the event loop).
625
626	You can ensure that C<< -recv >> never blocks by setting a callback and	808	You can ensure that C<< -recv >> never blocks by setting a callback and
627	only calling C<< ->recv >> from within that callback (or at a later	809	only calling C<< ->recv >> from within that callback (or at a later
628	time). This will work even when the event loop does not support blocking	810	time). This will work even when the event loop does not support blocking
629	waits otherwise.	811	waits otherwise.
630		812
…		…
636	=item $cb = $cv->cb ($cb->($cv))	818	=item $cb = $cv->cb ($cb->($cv))
637		819
638	This is a mutator function that returns the callback set and optionally	820	This is a mutator function that returns the callback set and optionally
639	replaces it before doing so.	821	replaces it before doing so.
640		822
641	The callback will be called when the condition becomes "true", i.e. when	823	The callback will be called when the condition becomes (or already was)
642	C<send> or C<croak> are called, with the only argument being the condition	824	"true", i.e. when C<send> or C<croak> are called (or were called), with
643	variable itself. Calling C<recv> inside the callback or at any later time	825	the only argument being the condition variable itself. Calling C<recv>
644	is guaranteed not to block.	826	inside the callback or at any later time is guaranteed not to block.
645		827
646	=back	828	=back
647		829
		830	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		831
		832	The available backend classes are (every class has its own manpage):
		833
		834	=over 4
		835
		836	=item Backends that are autoprobed when no other event loop can be found.
		837
		838	EV is the preferred backend when no other event loop seems to be in
		839	use. If EV is not installed, then AnyEvent will fall back to its own
		840	pure-perl implementation, which is available everywhere as it comes with
		841	AnyEvent itself.
		842
		843	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		844	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		845
		846	=item Backends that are transparently being picked up when they are used.
		847
		848	These will be used when they are currently loaded when the first watcher
		849	is created, in which case it is assumed that the application is using
		850	them. This means that AnyEvent will automatically pick the right backend
		851	when the main program loads an event module before anything starts to
		852	create watchers. Nothing special needs to be done by the main program.
		853
		854	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		855	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		856	AnyEvent::Impl::Tk based on Tk, very broken.
		857	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		858	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		859	AnyEvent::Impl::Irssi used when running within irssi.
		860
		861	=item Backends with special needs.
		862
		863	Qt requires the Qt::Application to be instantiated first, but will
		864	otherwise be picked up automatically. As long as the main program
		865	instantiates the application before any AnyEvent watchers are created,
		866	everything should just work.
		867
		868	AnyEvent::Impl::Qt based on Qt.
		869
		870	Support for IO::Async can only be partial, as it is too broken and
		871	architecturally limited to even support the AnyEvent API. It also
		872	is the only event loop that needs the loop to be set explicitly, so
		873	it can only be used by a main program knowing about AnyEvent. See
		874	L<AnyEvent::Impl::Async> for the gory details.
		875
		876	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		877
		878	=item Event loops that are indirectly supported via other backends.
		879
		880	Some event loops can be supported via other modules:
		881
		882	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		883
		884	B<WxWidgets> has no support for watching file handles. However, you can
		885	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		886	polls 20 times per second, which was considered to be too horrible to even
		887	consider for AnyEvent.
		888
		889	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		890	backend, so it can be supported through POE.
		891
		892	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		893	load L<POE> when detecting them, in the hope that POE will pick them up,
		894	in which case everything will be automatic.
		895
		896	=back
		897
648	=head1 GLOBAL VARIABLES AND FUNCTIONS	898	=head1 GLOBAL VARIABLES AND FUNCTIONS
649		899
		900	These are not normally required to use AnyEvent, but can be useful to
		901	write AnyEvent extension modules.
		902
650	=over 4	903	=over 4
651		904
652	=item $AnyEvent::MODEL	905	=item $AnyEvent::MODEL
653		906
654	Contains C<undef> until the first watcher is being created. Then it	907	Contains C<undef> until the first watcher is being created, before the
		908	backend has been autodetected.
		909
655	contains the event model that is being used, which is the name of the	910	Afterwards it contains the event model that is being used, which is the
656	Perl class implementing the model. This class is usually one of the	911	name of the Perl class implementing the model. This class is usually one
657	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	912	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
658	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	913	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
659		914	will be C<urxvt::anyevent>).
660	The known classes so far are:
661
662	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
663	AnyEvent::Impl::Event based on Event, second best choice.
664	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
665	AnyEvent::Impl::Glib based on Glib, third-best choice.
666	AnyEvent::Impl::Tk based on Tk, very bad choice.
667	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
668	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
669	AnyEvent::Impl::POE based on POE, not generic enough for full support.
670
671	There is no support for WxWidgets, as WxWidgets has no support for
672	watching file handles. However, you can use WxWidgets through the
673	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
674	second, which was considered to be too horrible to even consider for
675	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
676	it's adaptor.
677
678	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
679	autodetecting them.
680		915
681	=item AnyEvent::detect	916	=item AnyEvent::detect
682		917
683	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	918	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
684	if necessary. You should only call this function right before you would	919	if necessary. You should only call this function right before you would
685	have created an AnyEvent watcher anyway, that is, as late as possible at	920	have created an AnyEvent watcher anyway, that is, as late as possible at
686	runtime.	921	runtime, and not e.g. while initialising of your module.
		922
		923	If you need to do some initialisation before AnyEvent watchers are
		924	created, use C<post_detect>.
687		925
688	=item $guard = AnyEvent::post_detect { BLOCK }	926	=item $guard = AnyEvent::post_detect { BLOCK }
689		927
690	Arranges for the code block to be executed as soon as the event model is	928	Arranges for the code block to be executed as soon as the event model is
691	autodetected (or immediately if this has already happened).	929	autodetected (or immediately if this has already happened).
692		930
		931	The block will be executed I<after> the actual backend has been detected
		932	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		933	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		934	other initialisations - see the sources of L<AnyEvent::Strict> or
		935	L<AnyEvent::AIO> to see how this is used.
		936
		937	The most common usage is to create some global watchers, without forcing
		938	event module detection too early, for example, L<AnyEvent::AIO> creates
		939	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		940	avoid autodetecting the event module at load time.
		941
693	If called in scalar or list context, then it creates and returns an object	942	If called in scalar or list context, then it creates and returns an object
694	that automatically removes the callback again when it is destroyed. See	943	that automatically removes the callback again when it is destroyed (or
		944	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
695	L<Coro::BDB> for a case where this is useful.	945	a case where this is useful.
		946
		947	Example: Create a watcher for the IO::AIO module and store it in
		948	C<$WATCHER>. Only do so after the event loop is initialised, though.
		949
		950	our WATCHER;
		951
		952	my $guard = AnyEvent::post_detect {
		953	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		954	};
		955
		956	# the ||= is important in case post_detect immediately runs the block,
		957	# as to not clobber the newly-created watcher. assigning both watcher and
		958	# post_detect guard to the same variable has the advantage of users being
		959	# able to just C<undef $WATCHER> if the watcher causes them grief.
		960
		961	$WATCHER ||= $guard;
696		962
697	=item @AnyEvent::post_detect	963	=item @AnyEvent::post_detect
698		964
699	If there are any code references in this array (you can C<push> to it	965	If there are any code references in this array (you can C<push> to it
700	before or after loading AnyEvent), then they will called directly after	966	before or after loading AnyEvent), then they will called directly after
701	the event loop has been chosen.	967	the event loop has been chosen.
702		968
703	You should check C<$AnyEvent::MODEL> before adding to this array, though:	969	You should check C<$AnyEvent::MODEL> before adding to this array, though:
704	if it contains a true value then the event loop has already been detected,	970	if it is defined then the event loop has already been detected, and the
705	and the array will be ignored.	971	array will be ignored.
706		972
707	Best use C<AnyEvent::post_detect { BLOCK }> instead.	973	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		974	it, as it takes care of these details.
		975
		976	This variable is mainly useful for modules that can do something useful
		977	when AnyEvent is used and thus want to know when it is initialised, but do
		978	not need to even load it by default. This array provides the means to hook
		979	into AnyEvent passively, without loading it.
		980
		981	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		982	together, you could put this into Coro (this is the actual code used by
		983	Coro to accomplish this):
		984
		985	if (defined $AnyEvent::MODEL) {
		986	# AnyEvent already initialised, so load Coro::AnyEvent
		987	require Coro::AnyEvent;
		988	} else {
		989	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		990	# as soon as it is
		991	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		992	}
708		993
709	=back	994	=back
710		995
711	=head1 WHAT TO DO IN A MODULE	996	=head1 WHAT TO DO IN A MODULE
712		997
…		…
767		1052
768		1053
769	=head1 OTHER MODULES	1054	=head1 OTHER MODULES
770		1055
771	The following is a non-exhaustive list of additional modules that use	1056	The following is a non-exhaustive list of additional modules that use
772	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1057	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
773	in the same program. Some of the modules come with AnyEvent, some are	1058	modules and other event loops in the same program. Some of the modules
774	available via CPAN.	1059	come with AnyEvent, most are available via CPAN.
775		1060
776	=over 4	1061	=over 4
777		1062
778	=item L<AnyEvent::Util>	1063	=item L<AnyEvent::Util>
779		1064
…		…
788		1073
789	=item L<AnyEvent::Handle>	1074	=item L<AnyEvent::Handle>
790		1075
791	Provide read and write buffers, manages watchers for reads and writes,	1076	Provide read and write buffers, manages watchers for reads and writes,
792	supports raw and formatted I/O, I/O queued and fully transparent and	1077	supports raw and formatted I/O, I/O queued and fully transparent and
793	non-blocking SSL/TLS.	1078	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
794		1079
795	=item L<AnyEvent::DNS>	1080	=item L<AnyEvent::DNS>
796		1081
797	Provides rich asynchronous DNS resolver capabilities.	1082	Provides rich asynchronous DNS resolver capabilities.
798		1083
…		…
826		1111
827	=item L<AnyEvent::GPSD>	1112	=item L<AnyEvent::GPSD>
828		1113
829	A non-blocking interface to gpsd, a daemon delivering GPS information.	1114	A non-blocking interface to gpsd, a daemon delivering GPS information.
830		1115
		1116	=item L<AnyEvent::IRC>
		1117
		1118	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1119
		1120	=item L<AnyEvent::XMPP>
		1121
		1122	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1123	Net::XMPP2>.
		1124
831	=item L<AnyEvent::IGS>	1125	=item L<AnyEvent::IGS>
832		1126
833	A non-blocking interface to the Internet Go Server protocol (used by	1127	A non-blocking interface to the Internet Go Server protocol (used by
834	L<App::IGS>).	1128	L<App::IGS>).
835		1129
836	=item L<AnyEvent::IRC>
837
838	AnyEvent based IRC client module family (replacing the older Net::IRC3).
839
840	=item L<Net::XMPP2>
841
842	AnyEvent based XMPP (Jabber protocol) module family.
843
844	=item L<Net::FCP>	1130	=item L<Net::FCP>
845		1131
846	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1132	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
847	of AnyEvent.	1133	of AnyEvent.
848		1134
…		…
852		1138
853	=item L<Coro>	1139	=item L<Coro>
854		1140
855	Has special support for AnyEvent via L<Coro::AnyEvent>.	1141	Has special support for AnyEvent via L<Coro::AnyEvent>.
856		1142
857	=item L<IO::Lambda>
858
859	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
860
861	=back	1143	=back
862		1144
863	=cut	1145	=cut
864		1146
865	package AnyEvent;	1147	package AnyEvent;
866		1148
867	no warnings;	1149	# basically a tuned-down version of common::sense
868	use strict qw(vars subs);	1150	sub common_sense {
		1151	# from common:.sense 1.0
		1152	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
		1153	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1154	$^H |= 0x00000600;
		1155	}
869		1156
		1157	BEGIN { AnyEvent::common_sense }
		1158
870	use Carp;	1159	use Carp ();
871		1160
872	our $VERSION = 4.341;	1161	our $VERSION = '5.23';
873	our $MODEL;	1162	our $MODEL;
874		1163
875	our $AUTOLOAD;	1164	our $AUTOLOAD;
876	our @ISA;	1165	our @ISA;
877		1166
878	our @REGISTRY;	1167	our @REGISTRY;
879		1168
880	our $WIN32;	1169	our $VERBOSE;
881		1170
882	BEGIN {	1171	BEGIN {
883	my $win32 = ! ! ($^O =~ /mswin32/i);	1172	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
884	eval "sub WIN32(){ $win32 }";	1173	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
885	}
886		1174
		1175	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1176	if ${^TAINT};
		1177
887	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1178	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1179
		1180	}
		1181
		1182	our $MAX_SIGNAL_LATENCY = 10;
888		1183
889	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1184	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
890		1185
891	{	1186	{
892	my $idx;	1187	my $idx;
…		…
894	for reverse split /\s*,\s*/,	1189	for reverse split /\s*,\s*/,
895	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1190	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
896	}	1191	}
897		1192
898	my @models = (	1193	my @models = (
899	[EV:: => AnyEvent::Impl::EV::],	1194	[EV:: => AnyEvent::Impl::EV:: , 1],
900	[Event:: => AnyEvent::Impl::Event::],
901	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1195	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
902	# everything below here will not be autoprobed	1196	# everything below here will not (normally) be autoprobed
903	# as the pureperl backend should work everywhere	1197	# as the pureperl backend should work everywhere
904	# and is usually faster	1198	# and is usually faster
		1199	[Event:: => AnyEvent::Impl::Event::, 1],
		1200	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1201	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1202	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
905	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1203	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
906	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
907	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
908	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1204	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
909	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1205	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
910	[Wx:: => AnyEvent::Impl::POE::],	1206	[Wx:: => AnyEvent::Impl::POE::],
911	[Prima:: => AnyEvent::Impl::POE::],	1207	[Prima:: => AnyEvent::Impl::POE::],
		1208	# IO::Async is just too broken - we would need workarounds for its
		1209	# byzantine signal and broken child handling, among others.
		1210	# IO::Async is rather hard to detect, as it doesn't have any
		1211	# obvious default class.
		1212	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1213	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1214	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1215	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
912	);	1216	);
913		1217
914	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1218	our %method = map +($_ => 1),
		1219	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
915		1220
916	our @post_detect;	1221	our @post_detect;
917		1222
918	sub post_detect(&) {	1223	sub post_detect(&) {
919	my ($cb) = @_;	1224	my ($cb) = @_;
920		1225
921	if ($MODEL) {	1226	if ($MODEL) {
922	$cb->();	1227	$cb->();
923		1228
924	1	1229	undef
925	} else {	1230	} else {
926	push @post_detect, $cb;	1231	push @post_detect, $cb;
927		1232
928	defined wantarray	1233	defined wantarray
929	? bless \$cb, "AnyEvent::Util::PostDetect"	1234	? bless \$cb, "AnyEvent::Util::postdetect"
930	: ()	1235	: ()
931	}	1236	}
932	}	1237	}
933		1238
934	sub AnyEvent::Util::PostDetect::DESTROY {	1239	sub AnyEvent::Util::postdetect::DESTROY {
935	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1240	@post_detect = grep $_ != ${$_[0]}, @post_detect;
936	}	1241	}
937		1242
938	sub detect() {	1243	sub detect() {
939	unless ($MODEL) {	1244	unless ($MODEL) {
940	no strict 'refs';
941	local $SIG{__DIE__};	1245	local $SIG{__DIE__};
942		1246
943	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1247	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
944	my $model = "AnyEvent::Impl::$1";	1248	my $model = "AnyEvent::Impl::$1";
945	if (eval "require $model") {	1249	if (eval "require $model") {
946	$MODEL = $model;	1250	$MODEL = $model;
947	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1251	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
948	} else {	1252	} else {
949	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1253	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
950	}	1254	}
951	}	1255	}
952		1256
953	# check for already loaded models	1257	# check for already loaded models
954	unless ($MODEL) {	1258	unless ($MODEL) {
955	for (@REGISTRY, @models) {	1259	for (@REGISTRY, @models) {
956	my ($package, $model) = @$_;	1260	my ($package, $model) = @$_;
957	if (${"$package\::VERSION"} > 0) {	1261	if (${"$package\::VERSION"} > 0) {
958	if (eval "require $model") {	1262	if (eval "require $model") {
959	$MODEL = $model;	1263	$MODEL = $model;
960	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1264	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
961	last;	1265	last;
962	}	1266	}
963	}	1267	}
964	}	1268	}
965		1269
966	unless ($MODEL) {	1270	unless ($MODEL) {
967	# try to load a model	1271	# try to autoload a model
968
969	for (@REGISTRY, @models) {	1272	for (@REGISTRY, @models) {
970	my ($package, $model) = @$_;	1273	my ($package, $model, $autoload) = @$_;
		1274	if (
		1275	$autoload
971	if (eval "require $package"	1276	and eval "require $package"
972	and ${"$package\::VERSION"} > 0	1277	and ${"$package\::VERSION"} > 0
973	and eval "require $model") {	1278	and eval "require $model"
		1279	) {
974	$MODEL = $model;	1280	$MODEL = $model;
975	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1281	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
976	last;	1282	last;
977	}	1283	}
978	}	1284	}
979		1285
980	$MODEL	1286	$MODEL
981	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1287	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
982	}	1288	}
983	}	1289	}
984		1290
985	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1291	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
986		1292
…		…
996		1302
997	sub AUTOLOAD {	1303	sub AUTOLOAD {
998	(my $func = $AUTOLOAD) =~ s/.*://;	1304	(my $func = $AUTOLOAD) =~ s/.*://;
999		1305
1000	$method{$func}	1306	$method{$func}
1001	or croak "$func: not a valid method for AnyEvent objects";	1307	or Carp::croak "$func: not a valid method for AnyEvent objects";
1002		1308
1003	detect unless $MODEL;	1309	detect unless $MODEL;
1004		1310
1005	my $class = shift;	1311	my $class = shift;
1006	$class->$func (@_);	1312	$class->$func (@_);
1007	}	1313	}
1008		1314
1009	# utility function to dup a filehandle. this is used by many backends	1315	# utility function to dup a filehandle. this is used by many backends
1010	# to support binding more than one watcher per filehandle (they usually	1316	# to support binding more than one watcher per filehandle (they usually
1011	# allow only one watcher per fd, so we dup it to get a different one).	1317	# allow only one watcher per fd, so we dup it to get a different one).
1012	sub _dupfh($$$$) {	1318	sub _dupfh($$;$$) {
1013	my ($poll, $fh, $r, $w) = @_;	1319	my ($poll, $fh, $r, $w) = @_;
1014		1320
1015	# cygwin requires the fh mode to be matching, unix doesn't	1321	# cygwin requires the fh mode to be matching, unix doesn't
1016	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1322	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1017	: $poll eq "w" ? ($w, ">")
1018	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1019		1323
1020	open my $fh2, "$mode&" . fileno $fh	1324	open my $fh2, $mode, $fh
1021	or die "cannot dup() filehandle: $!";	1325	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1022		1326
1023	# we assume CLOEXEC is already set by perl in all important cases	1327	# we assume CLOEXEC is already set by perl in all important cases
1024		1328
1025	($fh2, $rw)	1329	($fh2, $rw)
1026	}	1330	}
1027		1331
		1332	=head1 SIMPLIFIED AE API
		1333
		1334	Starting with version 5.0, AnyEvent officially supports a second, much
		1335	simpler, API that is designed to reduce the calling, typing and memory
		1336	overhead.
		1337
		1338	See the L<AE> manpage for details.
		1339
		1340	=cut
		1341
		1342	package AE;
		1343
		1344	our $VERSION = $AnyEvent::VERSION;
		1345
		1346	sub io($$$) {
		1347	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1348	}
		1349
		1350	sub timer($$$) {
		1351	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1352	}
		1353
		1354	sub signal($$) {
		1355	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1356	}
		1357
		1358	sub child($$) {
		1359	AnyEvent->child (pid => $_[0], cb => $_[1])
		1360	}
		1361
		1362	sub idle($) {
		1363	AnyEvent->idle (cb => $_[0])
		1364	}
		1365
		1366	sub cv(;&) {
		1367	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1368	}
		1369
		1370	sub now() {
		1371	AnyEvent->now
		1372	}
		1373
		1374	sub now_update() {
		1375	AnyEvent->now_update
		1376	}
		1377
		1378	sub time() {
		1379	AnyEvent->time
		1380	}
		1381
1028	package AnyEvent::Base;	1382	package AnyEvent::Base;
1029		1383
1030	# default implementation for now and time	1384	# default implementations for many methods
1031		1385
1032	BEGIN {	1386	sub _time() {
		1387	# probe for availability of Time::HiRes
1033	if (eval "use Time::HiRes (); time (); 1") {	1388	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1389	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1034	*_time = \&Time::HiRes::time;	1390	*_time = \&Time::HiRes::time;
1035	# if (eval "use POSIX (); (POSIX::times())...	1391	# if (eval "use POSIX (); (POSIX::times())...
1036	} else {	1392	} else {
		1393	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1037	*_time = sub { time }; # epic fail	1394	*_time = sub { time }; # epic fail
1038	}	1395	}
		1396
		1397	&_time
1039	}	1398	}
1040		1399
1041	sub time { _time }	1400	sub time { _time }
1042	sub now { _time }	1401	sub now { _time }
		1402	sub now_update { }
1043		1403
1044	# default implementation for ->condvar	1404	# default implementation for ->condvar
1045		1405
1046	sub condvar {	1406	sub condvar {
1047	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1407	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1048	}	1408	}
1049		1409
1050	# default implementation for ->signal	1410	# default implementation for ->signal
1051		1411
		1412	our $HAVE_ASYNC_INTERRUPT;
		1413
		1414	sub _have_async_interrupt() {
		1415	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1416	&& eval "use Async::Interrupt 1.02 (); 1")
		1417	unless defined $HAVE_ASYNC_INTERRUPT;
		1418
		1419	$HAVE_ASYNC_INTERRUPT
		1420	}
		1421
1052	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1422	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1423	our (%SIG_ASY, %SIG_ASY_W);
		1424	our ($SIG_COUNT, $SIG_TW);
1053		1425
1054	sub _signal_exec {	1426	sub _signal_exec {
		1427	$HAVE_ASYNC_INTERRUPT
		1428	? $SIGPIPE_R->drain
1055	sysread $SIGPIPE_R, my $dummy, 4;	1429	: sysread $SIGPIPE_R, (my $dummy), 9;
1056		1430
1057	while (%SIG_EV) {	1431	while (%SIG_EV) {
1058	for (keys %SIG_EV) {	1432	for (keys %SIG_EV) {
1059	delete $SIG_EV{$_};	1433	delete $SIG_EV{$_};
1060	$_->() for values %{ $SIG_CB{$_} || {} };	1434	$_->() for values %{ $SIG_CB{$_} || {} };
1061	}	1435	}
1062	}	1436	}
1063	}	1437	}
1064		1438
		1439	# install a dummy wakeup watcher to reduce signal catching latency
		1440	sub _sig_add() {
		1441	unless ($SIG_COUNT++) {
		1442	# try to align timer on a full-second boundary, if possible
		1443	my $NOW = AE::now;
		1444
		1445	$SIG_TW = AE::timer
		1446	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1447	$MAX_SIGNAL_LATENCY,
		1448	sub { } # just for the PERL_ASYNC_CHECK
		1449	;
		1450	}
		1451	}
		1452
		1453	sub _sig_del {
		1454	undef $SIG_TW
		1455	unless --$SIG_COUNT;
		1456	}
		1457
		1458	our $_sig_name_init; $_sig_name_init = sub {
		1459	eval q{ # poor man's autoloading
		1460	undef $_sig_name_init;
		1461
		1462	if (_have_async_interrupt) {
		1463	*sig2num = \&Async::Interrupt::sig2num;
		1464	*sig2name = \&Async::Interrupt::sig2name;
		1465	} else {
		1466	require Config;
		1467
		1468	my %signame2num;
		1469	@signame2num{ split ' ', $Config::Config{sig_name} }
		1470	= split ' ', $Config::Config{sig_num};
		1471
		1472	my @signum2name;
		1473	@signum2name[values %signame2num] = keys %signame2num;
		1474
		1475	*sig2num = sub($) {
		1476	$_[0] > 0 ? shift : $signame2num{+shift}
		1477	};
		1478	*sig2name = sub ($) {
		1479	$_[0] > 0 ? $signum2name[+shift] : shift
		1480	};
		1481	}
		1482	};
		1483	die if $@;
		1484	};
		1485
		1486	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1487	sub sig2name($) { &$_sig_name_init; &sig2name }
		1488
1065	sub signal {	1489	sub signal {
1066	my (undef, %arg) = @_;	1490	eval q{ # poor man's autoloading {}
		1491	# probe for availability of Async::Interrupt
		1492	if (_have_async_interrupt) {
		1493	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1067		1494
1068	unless ($SIGPIPE_R) {	1495	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1069	if (AnyEvent::WIN32) {	1496	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1070	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();	1497
1071	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1072	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1073	} else {	1498	} else {
1074	pipe $SIGPIPE_R, $SIGPIPE_W;	1499	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1500
1075	require Fcntl;	1501	require Fcntl;
		1502
		1503	if (AnyEvent::WIN32) {
		1504	require AnyEvent::Util;
		1505
		1506	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1507	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1508	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1509	} else {
		1510	pipe $SIGPIPE_R, $SIGPIPE_W;
1076	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1511	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1077	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1512	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1513
		1514	# not strictly required, as $^F is normally 2, but let's make sure...
		1515	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1516	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1517	}
		1518
		1519	$SIGPIPE_R
		1520	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1521
		1522	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1078	}	1523	}
1079		1524
1080	$SIGPIPE_R	1525	*signal = sub {
1081	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1526	my (undef, %arg) = @_;
1082		1527
1083	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1084	}
1085
1086	my $signal = uc $arg{signal}	1528	my $signal = uc $arg{signal}
1087	or Carp::croak "required option 'signal' is missing";	1529	or Carp::croak "required option 'signal' is missing";
1088		1530
		1531	if ($HAVE_ASYNC_INTERRUPT) {
		1532	# async::interrupt
		1533
		1534	$signal = sig2num $signal;
1089	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1535	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1536
		1537	$SIG_ASY{$signal} ||= new Async::Interrupt
		1538	cb => sub { undef $SIG_EV{$signal} },
		1539	signal => $signal,
		1540	pipe => [$SIGPIPE_R->filenos],
		1541	pipe_autodrain => 0,
		1542	;
		1543
		1544	} else {
		1545	# pure perl
		1546
		1547	# AE::Util has been loaded in signal
		1548	$signal = sig2name $signal;
		1549	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1550
1090	$SIG{$signal} ||= sub {	1551	$SIG{$signal} ||= sub {
		1552	local $!;
1091	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1553	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1092	undef $SIG_EV{$signal};	1554	undef $SIG_EV{$signal};
		1555	};
		1556
		1557	# can't do signal processing without introducing races in pure perl,
		1558	# so limit the signal latency.
		1559	_sig_add;
		1560	}
		1561
		1562	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1563	};
		1564
		1565	*AnyEvent::Base::signal::DESTROY = sub {
		1566	my ($signal, $cb) = @{$_[0]};
		1567
		1568	_sig_del;
		1569
		1570	delete $SIG_CB{$signal}{$cb};
		1571
		1572	$HAVE_ASYNC_INTERRUPT
		1573	? delete $SIG_ASY{$signal}
		1574	: # delete doesn't work with older perls - they then
		1575	# print weird messages, or just unconditionally exit
		1576	# instead of getting the default action.
		1577	undef $SIG{$signal}
		1578	unless keys %{ $SIG_CB{$signal} };
		1579	};
1093	};	1580	};
1094		1581	die if $@;
1095	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1582	&signal
1096	}
1097
1098	sub AnyEvent::Base::Signal::DESTROY {
1099	my ($signal, $cb) = @{$_[0]};
1100
1101	delete $SIG_CB{$signal}{$cb};
1102
1103	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1104	}	1583	}
1105		1584
1106	# default implementation for ->child	1585	# default implementation for ->child
1107		1586
1108	our %PID_CB;	1587	our %PID_CB;
1109	our $CHLD_W;	1588	our $CHLD_W;
1110	our $CHLD_DELAY_W;	1589	our $CHLD_DELAY_W;
1111	our $PID_IDLE;
1112	our $WNOHANG;	1590	our $WNOHANG;
1113		1591
1114	sub _child_wait {	1592	sub _emit_childstatus($$) {
1115	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1593	my (undef, $rpid, $rstatus) = @_;
		1594
		1595	$_->($rpid, $rstatus)
1116	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1596	for values %{ $PID_CB{$rpid} || {} },
1117	(values %{ $PID_CB{0} || {} });	1597	values %{ $PID_CB{0} || {} };
1118	}
1119
1120	undef $PID_IDLE;
1121	}	1598	}
1122		1599
1123	sub _sigchld {	1600	sub _sigchld {
1124	# make sure we deliver these changes "synchronous" with the event loop.	1601	my $pid;
1125	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {	1602
1126	undef $CHLD_DELAY_W;	1603	AnyEvent->_emit_childstatus ($pid, $?)
1127	&_child_wait;	1604	while ($pid = waitpid -1, $WNOHANG) > 0;
1128	});
1129	}	1605	}
1130		1606
1131	sub child {	1607	sub child {
1132	my (undef, %arg) = @_;	1608	my (undef, %arg) = @_;
1133		1609
1134	defined (my $pid = $arg{pid} + 0)	1610	defined (my $pid = $arg{pid} + 0)
1135	or Carp::croak "required option 'pid' is missing";	1611	or Carp::croak "required option 'pid' is missing";
1136		1612
1137	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1613	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1138		1614
1139	unless ($WNOHANG) {	1615	# WNOHANG is almost cetrainly 1 everywhere
		1616	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1617	? 1
1140	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1618	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1141	}
1142		1619
1143	unless ($CHLD_W) {	1620	unless ($CHLD_W) {
1144	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1621	$CHLD_W = AE::signal CHLD => \&_sigchld;
1145	# child could be a zombie already, so make at least one round	1622	# child could be a zombie already, so make at least one round
1146	&_sigchld;	1623	&_sigchld;
1147	}	1624	}
1148		1625
1149	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1626	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1150	}	1627	}
1151		1628
1152	sub AnyEvent::Base::Child::DESTROY {	1629	sub AnyEvent::Base::child::DESTROY {
1153	my ($pid, $cb) = @{$_[0]};	1630	my ($pid, $cb) = @{$_[0]};
1154		1631
1155	delete $PID_CB{$pid}{$cb};	1632	delete $PID_CB{$pid}{$cb};
1156	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1633	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1157		1634
1158	undef $CHLD_W unless keys %PID_CB;	1635	undef $CHLD_W unless keys %PID_CB;
1159	}	1636	}
1160		1637
		1638	# idle emulation is done by simply using a timer, regardless
		1639	# of whether the process is idle or not, and not letting
		1640	# the callback use more than 50% of the time.
		1641	sub idle {
		1642	my (undef, %arg) = @_;
		1643
		1644	my ($cb, $w, $rcb) = $arg{cb};
		1645
		1646	$rcb = sub {
		1647	if ($cb) {
		1648	$w = _time;
		1649	&$cb;
		1650	$w = _time - $w;
		1651
		1652	# never use more then 50% of the time for the idle watcher,
		1653	# within some limits
		1654	$w = 0.0001 if $w < 0.0001;
		1655	$w = 5 if $w > 5;
		1656
		1657	$w = AE::timer $w, 0, $rcb;
		1658	} else {
		1659	# clean up...
		1660	undef $w;
		1661	undef $rcb;
		1662	}
		1663	};
		1664
		1665	$w = AE::timer 0.05, 0, $rcb;
		1666
		1667	bless \\$cb, "AnyEvent::Base::idle"
		1668	}
		1669
		1670	sub AnyEvent::Base::idle::DESTROY {
		1671	undef $${$_[0]};
		1672	}
		1673
1161	package AnyEvent::CondVar;	1674	package AnyEvent::CondVar;
1162		1675
1163	our @ISA = AnyEvent::CondVar::Base::;	1676	our @ISA = AnyEvent::CondVar::Base::;
1164		1677
1165	package AnyEvent::CondVar::Base;	1678	package AnyEvent::CondVar::Base;
1166		1679
1167	use overload	1680	#use overload
1168	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1681	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1169	fallback => 1;	1682	# fallback => 1;
		1683
		1684	# save 300+ kilobytes by dirtily hardcoding overloading
		1685	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1686	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1687	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1688	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1689
		1690	our $WAITING;
1170		1691
1171	sub _send {	1692	sub _send {
1172	# nop	1693	# nop
1173	}	1694	}
1174		1695
…		…
1187	sub ready {	1708	sub ready {
1188	$_[0]{_ae_sent}	1709	$_[0]{_ae_sent}
1189	}	1710	}
1190		1711
1191	sub _wait {	1712	sub _wait {
		1713	$WAITING
		1714	and !$_[0]{_ae_sent}
		1715	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1716
		1717	local $WAITING = 1;
1192	AnyEvent->one_event while !$_[0]{_ae_sent};	1718	AnyEvent->one_event while !$_[0]{_ae_sent};
1193	}	1719	}
1194		1720
1195	sub recv {	1721	sub recv {
1196	$_[0]->_wait;	1722	$_[0]->_wait;
…		…
1198	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1724	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1199	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1725	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1200	}	1726	}
1201		1727
1202	sub cb {	1728	sub cb {
1203	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1729	my $cv = shift;
		1730
		1731	@_
		1732	and $cv->{_ae_cb} = shift
		1733	and $cv->{_ae_sent}
		1734	and (delete $cv->{_ae_cb})->($cv);
		1735
1204	$_[0]{_ae_cb}	1736	$cv->{_ae_cb}
1205	}	1737	}
1206		1738
1207	sub begin {	1739	sub begin {
1208	++$_[0]{_ae_counter};	1740	++$_[0]{_ae_counter};
1209	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1741	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1237	so on.	1769	so on.
1238		1770
1239	=head1 ENVIRONMENT VARIABLES	1771	=head1 ENVIRONMENT VARIABLES
1240		1772
1241	The following environment variables are used by this module or its	1773	The following environment variables are used by this module or its
1242	submodules:	1774	submodules.
		1775
		1776	Note that AnyEvent will remove I<all> environment variables starting with
		1777	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1778	enabled.
1243		1779
1244	=over 4	1780	=over 4
1245		1781
1246	=item C<PERL_ANYEVENT_VERBOSE>	1782	=item C<PERL_ANYEVENT_VERBOSE>
1247		1783
…		…
1254	C<PERL_ANYEVENT_MODEL>.	1790	C<PERL_ANYEVENT_MODEL>.
1255		1791
1256	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1792	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1257	model it chooses.	1793	model it chooses.
1258		1794
		1795	When set to C<8> or higher, then AnyEvent will report extra information on
		1796	which optional modules it loads and how it implements certain features.
		1797
1259	=item C<PERL_ANYEVENT_STRICT>	1798	=item C<PERL_ANYEVENT_STRICT>
1260		1799
1261	AnyEvent does not do much argument checking by default, as thorough	1800	AnyEvent does not do much argument checking by default, as thorough
1262	argument checking is very costly. Setting this variable to a true value	1801	argument checking is very costly. Setting this variable to a true value
1263	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1802	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1264	check the arguments passed to most method calls. If it finds any problems	1803	check the arguments passed to most method calls. If it finds any problems,
1265	it will croak.	1804	it will croak.
1266		1805
1267	In other words, enables "strict" mode.	1806	In other words, enables "strict" mode.
1268		1807
1269	Unlike C<use strict>, it is definitely recommended ot keep it off in	1808	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1270	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1809	>>, it is definitely recommended to keep it off in production. Keeping
1271	developing programs can be very useful, however.	1810	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1811	can be very useful, however.
1272		1812
1273	=item C<PERL_ANYEVENT_MODEL>	1813	=item C<PERL_ANYEVENT_MODEL>
1274		1814
1275	This can be used to specify the event model to be used by AnyEvent, before	1815	This can be used to specify the event model to be used by AnyEvent, before
1276	auto detection and -probing kicks in. It must be a string consisting	1816	auto detection and -probing kicks in. It must be a string consisting
…		…
1319		1859
1320	=item C<PERL_ANYEVENT_MAX_FORKS>	1860	=item C<PERL_ANYEVENT_MAX_FORKS>
1321		1861
1322	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1862	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1323	will create in parallel.	1863	will create in parallel.
		1864
		1865	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1866
		1867	The default value for the C<max_outstanding> parameter for the default DNS
		1868	resolver - this is the maximum number of parallel DNS requests that are
		1869	sent to the DNS server.
		1870
		1871	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1872
		1873	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1874	configuration) in the default resolver. When set to the empty string, no
		1875	default config will be used.
		1876
		1877	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1878
		1879	When neither C<ca_file> nor C<ca_path> was specified during
		1880	L<AnyEvent::TLS> context creation, and either of these environment
		1881	variables exist, they will be used to specify CA certificate locations
		1882	instead of a system-dependent default.
		1883
		1884	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1885
		1886	When these are set to C<1>, then the respective modules are not
		1887	loaded. Mostly good for testing AnyEvent itself.
1324		1888
1325	=back	1889	=back
1326		1890
1327	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1891	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1328		1892
…		…
1386	warn "read: $input\n"; # output what has been read	1950	warn "read: $input\n"; # output what has been read
1387	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1951	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1388	},	1952	},
1389	);	1953	);
1390		1954
1391	my $time_watcher; # can only be used once
1392
1393	sub new_timer {
1394	$timer = AnyEvent->timer (after => 1, cb => sub {	1955	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1395	warn "timeout\n"; # print 'timeout' about every second	1956	warn "timeout\n"; # print 'timeout' at most every second
1396	&new_timer; # and restart the time
1397	});	1957	});
1398	}
1399
1400	new_timer; # create first timer
1401		1958
1402	$cv->recv; # wait until user enters /^q/i	1959	$cv->recv; # wait until user enters /^q/i
1403		1960
1404	=head1 REAL-WORLD EXAMPLE	1961	=head1 REAL-WORLD EXAMPLE
1405		1962
…		…
1536	through AnyEvent. The benchmark creates a lot of timers (with a zero	2093	through AnyEvent. The benchmark creates a lot of timers (with a zero
1537	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2094	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1538	which it is), lets them fire exactly once and destroys them again.	2095	which it is), lets them fire exactly once and destroys them again.
1539		2096
1540	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2097	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1541	distribution.	2098	distribution. It uses the L<AE> interface, which makes a real difference
		2099	for the EV and Perl backends only.
1542		2100
1543	=head3 Explanation of the columns	2101	=head3 Explanation of the columns
1544		2102
1545	I<watcher> is the number of event watchers created/destroyed. Since	2103	I<watcher> is the number of event watchers created/destroyed. Since
1546	different event models feature vastly different performances, each event	2104	different event models feature vastly different performances, each event
…		…
1567	watcher.	2125	watcher.
1568		2126
1569	=head3 Results	2127	=head3 Results
1570		2128
1571	name watchers bytes create invoke destroy comment	2129	name watchers bytes create invoke destroy comment
1572	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2130	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1573	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2131	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1574	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2132	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1575	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2133	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1576	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2134	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1577	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2135	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2136	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2137	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1578	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2138	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1579	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2139	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1580	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2140	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1581	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2141	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1582		2142
1583	=head3 Discussion	2143	=head3 Discussion
1584		2144
1585	The benchmark does I<not> measure scalability of the event loop very	2145	The benchmark does I<not> measure scalability of the event loop very
1586	well. For example, a select-based event loop (such as the pure perl one)	2146	well. For example, a select-based event loop (such as the pure perl one)
…		…
1598	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2158	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1599	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2159	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1600	cycles with POE.	2160	cycles with POE.
1601		2161
1602	C<EV> is the sole leader regarding speed and memory use, which are both	2162	C<EV> is the sole leader regarding speed and memory use, which are both
1603	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2163	maximal/minimal, respectively. When using the L<AE> API there is zero
		2164	overhead (when going through the AnyEvent API create is about 5-6 times
		2165	slower, with other times being equal, so still uses far less memory than
1604	far less memory than any other event loop and is still faster than Event	2166	any other event loop and is still faster than Event natively).
1605	natively.
1606		2167
1607	The pure perl implementation is hit in a few sweet spots (both the	2168	The pure perl implementation is hit in a few sweet spots (both the
1608	constant timeout and the use of a single fd hit optimisations in the perl	2169	constant timeout and the use of a single fd hit optimisations in the perl
1609	interpreter and the backend itself). Nevertheless this shows that it	2170	interpreter and the backend itself). Nevertheless this shows that it
1610	adds very little overhead in itself. Like any select-based backend its	2171	adds very little overhead in itself. Like any select-based backend its
1611	performance becomes really bad with lots of file descriptors (and few of	2172	performance becomes really bad with lots of file descriptors (and few of
1612	them active), of course, but this was not subject of this benchmark.	2173	them active), of course, but this was not subject of this benchmark.
1613		2174
1614	The C<Event> module has a relatively high setup and callback invocation	2175	The C<Event> module has a relatively high setup and callback invocation
1615	cost, but overall scores in on the third place.	2176	cost, but overall scores in on the third place.
		2177
		2178	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2179	when using its pure perl backend.
1616		2180
1617	C<Glib>'s memory usage is quite a bit higher, but it features a	2181	C<Glib>'s memory usage is quite a bit higher, but it features a
1618	faster callback invocation and overall ends up in the same class as	2182	faster callback invocation and overall ends up in the same class as
1619	C<Event>. However, Glib scales extremely badly, doubling the number of	2183	C<Event>. However, Glib scales extremely badly, doubling the number of
1620	watchers increases the processing time by more than a factor of four,	2184	watchers increases the processing time by more than a factor of four,
…		…
1681	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2245	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1682	(1%) are active. This mirrors the activity of large servers with many	2246	(1%) are active. This mirrors the activity of large servers with many
1683	connections, most of which are idle at any one point in time.	2247	connections, most of which are idle at any one point in time.
1684		2248
1685	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2249	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1686	distribution.	2250	distribution. It uses the L<AE> interface, which makes a real difference
		2251	for the EV and Perl backends only.
1687		2252
1688	=head3 Explanation of the columns	2253	=head3 Explanation of the columns
1689		2254
1690	I<sockets> is the number of sockets, and twice the number of "servers" (as	2255	I<sockets> is the number of sockets, and twice the number of "servers" (as
1691	each server has a read and write socket end).	2256	each server has a read and write socket end).
…		…
1698	it to another server. This includes deleting the old timeout and creating	2263	it to another server. This includes deleting the old timeout and creating
1699	a new one that moves the timeout into the future.	2264	a new one that moves the timeout into the future.
1700		2265
1701	=head3 Results	2266	=head3 Results
1702		2267
1703	name sockets create request	2268	name sockets create request
1704	EV 20000 69.01 11.16	2269	EV 20000 62.66 7.99
1705	Perl 20000 73.32 35.87	2270	Perl 20000 68.32 32.64
1706	Event 20000 212.62 257.32	2271	IOAsync 20000 174.06 101.15 epoll
1707	Glib 20000 651.16 1896.30	2272	IOAsync 20000 174.67 610.84 poll
		2273	Event 20000 202.69 242.91
		2274	Glib 20000 557.01 1689.52
1708	POE 20000 349.67 12317.24 uses POE::Loop::Event	2275	POE 20000 341.54 12086.32 uses POE::Loop::Event
1709		2276
1710	=head3 Discussion	2277	=head3 Discussion
1711		2278
1712	This benchmark I<does> measure scalability and overall performance of the	2279	This benchmark I<does> measure scalability and overall performance of the
1713	particular event loop.	2280	particular event loop.
…		…
1715	EV is again fastest. Since it is using epoll on my system, the setup time	2282	EV is again fastest. Since it is using epoll on my system, the setup time
1716	is relatively high, though.	2283	is relatively high, though.
1717		2284
1718	Perl surprisingly comes second. It is much faster than the C-based event	2285	Perl surprisingly comes second. It is much faster than the C-based event
1719	loops Event and Glib.	2286	loops Event and Glib.
		2287
		2288	IO::Async performs very well when using its epoll backend, and still quite
		2289	good compared to Glib when using its pure perl backend.
1720		2290
1721	Event suffers from high setup time as well (look at its code and you will	2291	Event suffers from high setup time as well (look at its code and you will
1722	understand why). Callback invocation also has a high overhead compared to	2292	understand why). Callback invocation also has a high overhead compared to
1723	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2293	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1724	uses select or poll in basically all documented configurations.	2294	uses select or poll in basically all documented configurations.
…		…
1787	=item * C-based event loops perform very well with small number of	2357	=item * C-based event loops perform very well with small number of
1788	watchers, as the management overhead dominates.	2358	watchers, as the management overhead dominates.
1789		2359
1790	=back	2360	=back
1791		2361
		2362	=head2 THE IO::Lambda BENCHMARK
		2363
		2364	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2365	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2366	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2367	shouldn't come as a surprise to anybody). As such, the benchmark is
		2368	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2369	very optimal. But how would AnyEvent compare when used without the extra
		2370	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2371
		2372	The benchmark itself creates an echo-server, and then, for 500 times,
		2373	connects to the echo server, sends a line, waits for the reply, and then
		2374	creates the next connection. This is a rather bad benchmark, as it doesn't
		2375	test the efficiency of the framework or much non-blocking I/O, but it is a
		2376	benchmark nevertheless.
		2377
		2378	name runtime
		2379	Lambda/select 0.330 sec
		2380	+ optimized 0.122 sec
		2381	Lambda/AnyEvent 0.327 sec
		2382	+ optimized 0.138 sec
		2383	Raw sockets/select 0.077 sec
		2384	POE/select, components 0.662 sec
		2385	POE/select, raw sockets 0.226 sec
		2386	POE/select, optimized 0.404 sec
		2387
		2388	AnyEvent/select/nb 0.085 sec
		2389	AnyEvent/EV/nb 0.068 sec
		2390	+state machine 0.134 sec
		2391
		2392	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2393	benchmarks actually make blocking connects and use 100% blocking I/O,
		2394	defeating the purpose of an event-based solution. All of the newly
		2395	written AnyEvent benchmarks use 100% non-blocking connects (using
		2396	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2397	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2398	generally require a lot more bookkeeping and event handling than blocking
		2399	connects (which involve a single syscall only).
		2400
		2401	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2402	offers similar expressive power as POE and IO::Lambda, using conventional
		2403	Perl syntax. This means that both the echo server and the client are 100%
		2404	non-blocking, further placing it at a disadvantage.
		2405
		2406	As you can see, the AnyEvent + EV combination even beats the
		2407	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2408	backend easily beats IO::Lambda and POE.
		2409
		2410	And even the 100% non-blocking version written using the high-level (and
		2411	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2412	higher level ("unoptimised") abstractions by a large margin, even though
		2413	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
		2414
		2415	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2416	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2417	part of the IO::Lambda distribution and were used without any changes.
		2418
1792		2419
1793	=head1 SIGNALS	2420	=head1 SIGNALS
1794		2421
1795	AnyEvent currently installs handlers for these signals:	2422	AnyEvent currently installs handlers for these signals:
1796		2423
…		…
1799	=item SIGCHLD	2426	=item SIGCHLD
1800		2427
1801	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2428	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1802	emulation for event loops that do not support them natively. Also, some	2429	emulation for event loops that do not support them natively. Also, some
1803	event loops install a similar handler.	2430	event loops install a similar handler.
		2431
		2432	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2433	AnyEvent will reset it to default, to avoid losing child exit statuses.
1804		2434
1805	=item SIGPIPE	2435	=item SIGPIPE
1806		2436
1807	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2437	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1808	when AnyEvent gets loaded.	2438	when AnyEvent gets loaded.
…		…
1820		2450
1821	=back	2451	=back
1822		2452
1823	=cut	2453	=cut
1824		2454
		2455	undef $SIG{CHLD}
		2456	if $SIG{CHLD} eq 'IGNORE';
		2457
1825	$SIG{PIPE} = sub { }	2458	$SIG{PIPE} = sub { }
1826	unless defined $SIG{PIPE};	2459	unless defined $SIG{PIPE};
1827		2460
		2461	=head1 RECOMMENDED/OPTIONAL MODULES
		2462
		2463	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2464	it's built-in modules) are required to use it.
		2465
		2466	That does not mean that AnyEvent won't take advantage of some additional
		2467	modules if they are installed.
		2468
		2469	This section explains which additional modules will be used, and how they
		2470	affect AnyEvent's operation.
		2471
		2472	=over 4
		2473
		2474	=item L<Async::Interrupt>
		2475
		2476	This slightly arcane module is used to implement fast signal handling: To
		2477	my knowledge, there is no way to do completely race-free and quick
		2478	signal handling in pure perl. To ensure that signals still get
		2479	delivered, AnyEvent will start an interval timer to wake up perl (and
		2480	catch the signals) with some delay (default is 10 seconds, look for
		2481	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2482
		2483	If this module is available, then it will be used to implement signal
		2484	catching, which means that signals will not be delayed, and the event loop
		2485	will not be interrupted regularly, which is more efficient (and good for
		2486	battery life on laptops).
		2487
		2488	This affects not just the pure-perl event loop, but also other event loops
		2489	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2490
		2491	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2492	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2493	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2494	does nothing for those backends.
		2495
		2496	=item L<EV>
		2497
		2498	This module isn't really "optional", as it is simply one of the backend
		2499	event loops that AnyEvent can use. However, it is simply the best event
		2500	loop available in terms of features, speed and stability: It supports
		2501	the AnyEvent API optimally, implements all the watcher types in XS, does
		2502	automatic timer adjustments even when no monotonic clock is available,
		2503	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2504	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2505	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2506
		2507	=item L<Guard>
		2508
		2509	The guard module, when used, will be used to implement
		2510	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2511	lot less memory), but otherwise doesn't affect guard operation much. It is
		2512	purely used for performance.
		2513
		2514	=item L<JSON> and L<JSON::XS>
		2515
		2516	One of these modules is required when you want to read or write JSON data
		2517	via L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2518	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2519
		2520	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2521	installed.
		2522
		2523	=item L<Net::SSLeay>
		2524
		2525	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2526	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2527	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2528
		2529	=item L<Time::HiRes>
		2530
		2531	This module is part of perl since release 5.008. It will be used when the
		2532	chosen event library does not come with a timing source on it's own. The
		2533	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2534	try to use a monotonic clock for timing stability.
		2535
		2536	=back
		2537
1828		2538
1829	=head1 FORK	2539	=head1 FORK
1830		2540
1831	Most event libraries are not fork-safe. The ones who are usually are	2541	Most event libraries are not fork-safe. The ones who are usually are
1832	because they rely on inefficient but fork-safe C<select> or C<poll>	2542	because they rely on inefficient but fork-safe C<select> or C<poll> calls
1833	calls. Only L<EV> is fully fork-aware.	2543	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2544	are usually badly thought-out hacks that are incompatible with fork in
		2545	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2546	continue event-processing in both parent and child (or both, if you know
		2547	what you are doing).
		2548
		2549	This means that, in general, you cannot fork and do event processing in
		2550	the child if the event library was initialised before the fork (which
		2551	usually happens when the first AnyEvent watcher is created, or the library
		2552	is loaded).
1834		2553
1835	If you have to fork, you must either do so I<before> creating your first	2554	If you have to fork, you must either do so I<before> creating your first
1836	watcher OR you must not use AnyEvent at all in the child.	2555	watcher OR you must not use AnyEvent at all in the child OR you must do
		2556	something completely out of the scope of AnyEvent.
		2557
		2558	The problem of doing event processing in the parent I<and> the child
		2559	is much more complicated: even for backends that I<are> fork-aware or
		2560	fork-safe, their behaviour is not usually what you want: fork clones all
		2561	watchers, that means all timers, I/O watchers etc. are active in both
		2562	parent and child, which is almost never what you want. USing C<exec>
		2563	to start worker children from some kind of manage rprocess is usually
		2564	preferred, because it is much easier and cleaner, at the expense of having
		2565	to have another binary.
1837		2566
1838		2567
1839	=head1 SECURITY CONSIDERATIONS	2568	=head1 SECURITY CONSIDERATIONS
1840		2569
1841	AnyEvent can be forced to load any event model via	2570	AnyEvent can be forced to load any event model via
…		…
1853	use AnyEvent;	2582	use AnyEvent;
1854		2583
1855	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2584	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1856	be used to probe what backend is used and gain other information (which is	2585	be used to probe what backend is used and gain other information (which is
1857	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2586	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1858	$ENV{PERL_ANYEGENT_STRICT}.	2587	$ENV{PERL_ANYEVENT_STRICT}.
		2588
		2589	Note that AnyEvent will remove I<all> environment variables starting with
		2590	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2591	enabled.
1859		2592
1860		2593
1861	=head1 BUGS	2594	=head1 BUGS
1862		2595
1863	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2596	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
…		…
1875	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2608	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1876		2609
1877	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2610	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1878	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2611	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1879	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2612	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1880	L<AnyEvent::Impl::POE>.	2613	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1881		2614
1882	Non-blocking file handles, sockets, TCP clients and	2615	Non-blocking file handles, sockets, TCP clients and
1883	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2616	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1884		2617
1885	Asynchronous DNS: L<AnyEvent::DNS>.	2618	Asynchronous DNS: L<AnyEvent::DNS>.
1886		2619
1887	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2620	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2621	L<Coro::Event>,
1888		2622
1889	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2623	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2624	L<AnyEvent::HTTP>.
1890		2625
1891		2626
1892	=head1 AUTHOR	2627	=head1 AUTHOR
1893		2628
1894	Marc Lehmann <schmorp@schmorp.de>	2629	Marc Lehmann <schmorp@schmorp.de>

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