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Revision 1.320 by root, Mon Apr 12 02:50:31 2010 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
		6	and POE are various supported event loops/environments.
6		7
7	=head1 SYNOPSIS	8	=head1 SYNOPSIS
8		9
9	use AnyEvent;	10	use AnyEvent;
10		11
		12	# if you prefer function calls, look at the L<AE> manpage for
		13	# an alternative API.
		14
		15	# file handle or descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
12		17
		18	# one-shot or repeating timers
13	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
14	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
15		21
16	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
17	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
18		24
		25	# POSIX signal
19	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });	26	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
20		27
		28	# child process exit
21	my $w = AnyEvent->child (pid => $pid, cb => sub {	29	my $w = AnyEvent->child (pid => $pid, cb => sub {
22	my ($pid, $status) = @_;	30	my ($pid, $status) = @_;
23	...	31	...
24	});	32	});
		33
		34	# called when event loop idle (if applicable)
		35	my $w = AnyEvent->idle (cb => sub { ... });
25		36
26	my $w = AnyEvent->condvar; # stores whether a condition was flagged	37	my $w = AnyEvent->condvar; # stores whether a condition was flagged
27	$w->send; # wake up current and all future recv's	38	$w->send; # wake up current and all future recv's
28	$w->recv; # enters "main loop" till $condvar gets ->send	39	$w->recv; # enters "main loop" till $condvar gets ->send
29	# use a condvar in callback mode:	40	# use a condvar in callback mode:
…		…
32	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
33		44
34	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
35	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
36	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
		48
		49	=head1 SUPPORT
		50
		51	There is a mailinglist for discussing all things AnyEvent, and an IRC
		52	channel, too.
		53
		54	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		55	Repository>, at L<http://anyevent.schmorp.de>, for more info.
37		56
38	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	57	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
39		58
40	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	59	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
41	nowadays. So what is different about AnyEvent?	60	nowadays. So what is different about AnyEvent?
…		…
165	my variables are only visible after the statement in which they are	184	my variables are only visible after the statement in which they are
166	declared.	185	declared.
167		186
168	=head2 I/O WATCHERS	187	=head2 I/O WATCHERS
169		188
		189	$w = AnyEvent->io (
		190	fh => <filehandle_or_fileno>,
		191	poll => <"r" or "w">,
		192	cb => <callback>,
		193	);
		194
170	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	195	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
171	with the following mandatory key-value pairs as arguments:	196	with the following mandatory key-value pairs as arguments:
172		197
173	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events	198	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>	199	for events (AnyEvent might or might not keep a reference to this file
		200	handle). Note that only file handles pointing to things for which
		201	non-blocking operation makes sense are allowed. This includes sockets,
		202	most character devices, pipes, fifos and so on, but not for example files
		203	or block devices.
		204
175	must be a string that is either C<r> or C<w>, which creates a watcher	205	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	206	watcher waiting for "r"eadable or "w"ritable events, respectively.
		207
177	callback to invoke each time the file handle becomes ready.	208	C<cb> is the callback to invoke each time the file handle becomes ready.
178		209
179	Although the callback might get passed parameters, their value and	210	Although the callback might get passed parameters, their value and
180	presence is undefined and you cannot rely on them. Portable AnyEvent	211	presence is undefined and you cannot rely on them. Portable AnyEvent
181	callbacks cannot use arguments passed to I/O watcher callbacks.	212	callbacks cannot use arguments passed to I/O watcher callbacks.
182		213
…		…
197	undef $w;	228	undef $w;
198	});	229	});
199		230
200	=head2 TIME WATCHERS	231	=head2 TIME WATCHERS
201		232
		233	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		234
		235	$w = AnyEvent->timer (
		236	after => <fractional_seconds>,
		237	interval => <fractional_seconds>,
		238	cb => <callback>,
		239	);
		240
202	You can create a time watcher by calling the C<< AnyEvent->timer >>	241	You can create a time watcher by calling the C<< AnyEvent->timer >>
203	method with the following mandatory arguments:	242	method with the following mandatory arguments:
204		243
205	C<after> specifies after how many seconds (fractional values are	244	C<after> specifies after how many seconds (fractional values are
206	supported) the callback should be invoked. C<cb> is the callback to invoke	245	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	353	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	354	can get whatever behaviour you want with any event loop, by taking the
316	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	355	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
317	account.	356	account.
318		357
		358	=item AnyEvent->now_update
		359
		360	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		361	the current time for each loop iteration (see the discussion of L<<
		362	AnyEvent->now >>, above).
		363
		364	When a callback runs for a long time (or when the process sleeps), then
		365	this "current" time will differ substantially from the real time, which
		366	might affect timers and time-outs.
		367
		368	When this is the case, you can call this method, which will update the
		369	event loop's idea of "current time".
		370
		371	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		372	when mod_perl executes the script, then the event loop will have the wrong
		373	idea about the "current time" (being potentially far in the past, when the
		374	script ran the last time). In that case you should arrange a call to C<<
		375	AnyEvent->now_update >> each time the web server process wakes up again
		376	(e.g. at the start of your script, or in a handler).
		377
		378	Note that updating the time I<might> cause some events to be handled.
		379
319	=back	380	=back
320		381
321	=head2 SIGNAL WATCHERS	382	=head2 SIGNAL WATCHERS
		383
		384	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
322		385
323	You can watch for signals using a signal watcher, C<signal> is the signal	386	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	387	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
325	callback to be invoked whenever a signal occurs.	388	callback to be invoked whenever a signal occurs.
326		389
…		…
332	invocation, and callback invocation will be synchronous. Synchronous means	395	invocation, and callback invocation will be synchronous. Synchronous means
333	that it might take a while until the signal gets handled by the process,	396	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.	397	but it is guaranteed not to interrupt any other callbacks.
335		398
336	The main advantage of using these watchers is that you can share a signal	399	The main advantage of using these watchers is that you can share a signal
337	between multiple watchers.	400	between multiple watchers, and AnyEvent will ensure that signals will not
		401	interrupt your program at bad times.
338		402
339	This watcher might use C<%SIG>, so programs overwriting those signals	403	This watcher might use C<%SIG> (depending on the event loop used),
340	directly will likely not work correctly.	404	so programs overwriting those signals directly will likely not work
		405	correctly.
341		406
342	Example: exit on SIGINT	407	Example: exit on SIGINT
343		408
344	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	409	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
345		410
		411	=head3 Restart Behaviour
		412
		413	While restart behaviour is up to the event loop implementation, most will
		414	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		415	pure perl implementation).
		416
		417	=head3 Safe/Unsafe Signals
		418
		419	Perl signals can be either "safe" (synchronous to opcode handling) or
		420	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		421	latter might corrupt your memory.
		422
		423	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		424	i.e. they will not interrupt your running perl program but will only be
		425	called as part of the normal event handling (just like timer, I/O etc.
		426	callbacks, too).
		427
		428	=head3 Signal Races, Delays and Workarounds
		429
		430	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		431	callbacks to signals in a generic way, which is a pity, as you cannot
		432	do race-free signal handling in perl, requiring C libraries for
		433	this. AnyEvent will try to do it's best, which means in some cases,
		434	signals will be delayed. The maximum time a signal might be delayed is
		435	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		436	variable can be changed only before the first signal watcher is created,
		437	and should be left alone otherwise. This variable determines how often
		438	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		439	will cause fewer spurious wake-ups, which is better for power and CPU
		440	saving.
		441
		442	All these problems can be avoided by installing the optional
		443	L<Async::Interrupt> module, which works with most event loops. It will not
		444	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		445	(and not with L<POE> currently, as POE does it's own workaround with
		446	one-second latency). For those, you just have to suffer the delays.
		447
346	=head2 CHILD PROCESS WATCHERS	448	=head2 CHILD PROCESS WATCHERS
347		449
		450	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		451
348	You can also watch on a child process exit and catch its exit status.	452	You can also watch on a child process exit and catch its exit status.
349		453
350	The child process is specified by the C<pid> argument (if set to C<0>, it	454	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	455	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	456	croak). The watcher will be triggered only when the child process has
353	any trace events (stopped/continued).	457	finished and an exit status is available, not on any trace events
		458	(stopped/continued).
354		459
355	The callback will be called with the pid and exit status (as returned by	460	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	461	waitpid), so unlike other watcher types, you I<can> rely on child watcher
357	callback arguments.	462	callback arguments.
358		463
…		…
363		468
364	There is a slight catch to child watchers, however: you usually start them	469	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	470	I<after> the child process was created, and this means the process could
366	have exited already (and no SIGCHLD will be sent anymore).	471	have exited already (and no SIGCHLD will be sent anymore).
367		472
368	Not all event models handle this correctly (POE doesn't), but even for	473	Not all event models handle this correctly (neither POE nor IO::Async do,
		474	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	475	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).	476	the process exits (i.e. before you fork in the first place). AnyEvent's
		477	pure perl event loop handles all cases correctly regardless of when you
		478	start the watcher.
371		479
372	This means you cannot create a child watcher as the very first thing in an	480	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	481	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>).	482	watcher before you C<fork> the child (alternatively, you can call
		483	C<AnyEvent::detect>).
		484
		485	As most event loops do not support waiting for child events, they will be
		486	emulated by AnyEvent in most cases, in which the latency and race problems
		487	mentioned in the description of signal watchers apply.
375		488
376	Example: fork a process and wait for it	489	Example: fork a process and wait for it
377		490
378	my $done = AnyEvent->condvar;	491	my $done = AnyEvent->condvar;
379		492
…		…
389	);	502	);
390		503
391	# do something else, then wait for process exit	504	# do something else, then wait for process exit
392	$done->recv;	505	$done->recv;
393		506
		507	=head2 IDLE WATCHERS
		508
		509	$w = AnyEvent->idle (cb => <callback>);
		510
		511	Repeatedly invoke the callback after the process becomes idle, until
		512	either the watcher is destroyed or new events have been detected.
		513
		514	Idle watchers are useful when there is a need to do something, but it
		515	is not so important (or wise) to do it instantly. The callback will be
		516	invoked only when there is "nothing better to do", which is usually
		517	defined as "all outstanding events have been handled and no new events
		518	have been detected". That means that idle watchers ideally get invoked
		519	when the event loop has just polled for new events but none have been
		520	detected. Instead of blocking to wait for more events, the idle watchers
		521	will be invoked.
		522
		523	Unfortunately, most event loops do not really support idle watchers (only
		524	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		525	will simply call the callback "from time to time".
		526
		527	Example: read lines from STDIN, but only process them when the
		528	program is otherwise idle:
		529
		530	my @lines; # read data
		531	my $idle_w;
		532	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		533	push @lines, scalar <STDIN>;
		534
		535	# start an idle watcher, if not already done
		536	$idle_w ||= AnyEvent->idle (cb => sub {
		537	# handle only one line, when there are lines left
		538	if (my $line = shift @lines) {
		539	print "handled when idle: $line";
		540	} else {
		541	# otherwise disable the idle watcher again
		542	undef $idle_w;
		543	}
		544	});
		545	});
		546
394	=head2 CONDITION VARIABLES	547	=head2 CONDITION VARIABLES
		548
		549	$cv = AnyEvent->condvar;
		550
		551	$cv->send (<list>);
		552	my @res = $cv->recv;
395		553
396	If you are familiar with some event loops you will know that all of them	554	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	555	require you to run some blocking "loop", "run" or similar function that
398	will actively watch for new events and call your callbacks.	556	will actively watch for new events and call your callbacks.
399		557
400	AnyEvent is different, it expects somebody else to run the event loop and	558	AnyEvent is slightly different: it expects somebody else to run the event
401	will only block when necessary (usually when told by the user).	559	loop and will only block when necessary (usually when told by the user).
402		560
403	The instrument to do that is called a "condition variable", so called	561	The instrument to do that is called a "condition variable", so called
404	because they represent a condition that must become true.	562	because they represent a condition that must become true.
405		563
		564	Now is probably a good time to look at the examples further below.
		565
406	Condition variables can be created by calling the C<< AnyEvent->condvar	566	Condition variables can be created by calling the C<< AnyEvent->condvar
407	>> method, usually without arguments. The only argument pair allowed is	567	>> 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	568	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	569	becomes true, with the condition variable as the first argument (but not
411	the results).	570	the results).
412		571
413	After creation, the condition variable is "false" until it becomes "true"	572	After creation, the condition variable is "false" until it becomes "true"
…		…
418	Condition variables are similar to callbacks, except that you can	577	Condition variables are similar to callbacks, except that you can
419	optionally wait for them. They can also be called merge points - points	578	optionally wait for them. They can also be called merge points - points
420	in time where multiple outstanding events have been processed. And yet	579	in time where multiple outstanding events have been processed. And yet
421	another way to call them is transactions - each condition variable can be	580	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	581	used to represent a transaction, which finishes at some point and delivers
423	a result.	582	a result. And yet some people know them as "futures" - a promise to
		583	compute/deliver something that you can wait for.
424		584
425	Condition variables are very useful to signal that something has finished,	585	Condition variables are very useful to signal that something has finished,
426	for example, if you write a module that does asynchronous http requests,	586	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	587	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	588	availability of results. The user can either act when the callback is
…		…
449	eventually calls C<< -> send >>, and the "consumer side", which waits	609	eventually calls C<< -> send >>, and the "consumer side", which waits
450	for the send to occur.	610	for the send to occur.
451		611
452	Example: wait for a timer.	612	Example: wait for a timer.
453		613
454	# wait till the result is ready	614	# condition: "wait till the timer is fired"
455	my $result_ready = AnyEvent->condvar;	615	my $timer_fired = AnyEvent->condvar;
456		616
457	# do something such as adding a timer	617	# create the timer - we could wait for, say
458	# or socket watcher the calls $result_ready->send	618	# a handle becomign ready, or even an
459	# when the "result" is ready.	619	# AnyEvent::HTTP request to finish, but
460	# in this case, we simply use a timer:	620	# in this case, we simply use a timer:
461	my $w = AnyEvent->timer (	621	my $w = AnyEvent->timer (
462	after => 1,	622	after => 1,
463	cb => sub { $result_ready->send },	623	cb => sub { $timer_fired->send },
464	);	624	);
465		625
466	# this "blocks" (while handling events) till the callback	626	# this "blocks" (while handling events) till the callback
467	# calls send	627	# calls ->send
468	$result_ready->recv;	628	$timer_fired->recv;
469		629
470	Example: wait for a timer, but take advantage of the fact that	630	Example: wait for a timer, but take advantage of the fact that condition
471	condition variables are also code references.	631	variables are also callable directly.
472		632
473	my $done = AnyEvent->condvar;	633	my $done = AnyEvent->condvar;
474	my $delay = AnyEvent->timer (after => 5, cb => $done);	634	my $delay = AnyEvent->timer (after => 5, cb => $done);
475	$done->recv;	635	$done->recv;
476		636
…		…
482		642
483	...	643	...
484		644
485	my @info = $couchdb->info->recv;	645	my @info = $couchdb->info->recv;
486		646
487	And this is how you would just ste a callback to be called whenever the	647	And this is how you would just set a callback to be called whenever the
488	results are available:	648	results are available:
489		649
490	$couchdb->info->cb (sub {	650	$couchdb->info->cb (sub {
491	my @info = $_[0]->recv;	651	my @info = $_[0]->recv;
492	});	652	});
…		…
510	immediately from within send.	670	immediately from within send.
511		671
512	Any arguments passed to the C<send> call will be returned by all	672	Any arguments passed to the C<send> call will be returned by all
513	future C<< ->recv >> calls.	673	future C<< ->recv >> calls.
514		674
515	Condition variables are overloaded so one can call them directly	675	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	676	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	677	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		678
524	=item $cv->croak ($error)	679	=item $cv->croak ($error)
525		680
526	Similar to send, but causes all call's to C<< ->recv >> to invoke	681	Similar to send, but causes all call's to C<< ->recv >> to invoke
527	C<Carp::croak> with the given error message/object/scalar.	682	C<Carp::croak> with the given error message/object/scalar.
528		683
529	This can be used to signal any errors to the condition variable	684	This can be used to signal any errors to the condition variable
530	user/consumer.	685	user/consumer. Doing it this way instead of calling C<croak> directly
		686	delays the error detetcion, but has the overwhelmign advantage that it
		687	diagnoses the error at the place where the result is expected, and not
		688	deep in some event clalback without connection to the actual code causing
		689	the problem.
531		690
532	=item $cv->begin ([group callback])	691	=item $cv->begin ([group callback])
533		692
534	=item $cv->end	693	=item $cv->end
535
536	These two methods are EXPERIMENTAL and MIGHT CHANGE.
537		694
538	These two methods can be used to combine many transactions/events into	695	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	696	one. For example, a function that pings many hosts in parallel might want
540	to use a condition variable for the whole process.	697	to use a condition variable for the whole process.
541		698
542	Every call to C<< ->begin >> will increment a counter, and every call to	699	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	700	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	701	>>, 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	702	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.	703	>>, but that is not required. If no group callback was set, C<send> will
		704	be called without any arguments.
547		705
548	Let's clarify this with the ping example:	706	You can think of C<< $cv->send >> giving you an OR condition (one call
		707	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		708	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		709
		710	Let's start with a simple example: you have two I/O watchers (for example,
		711	STDOUT and STDERR for a program), and you want to wait for both streams to
		712	close before activating a condvar:
549		713
550	my $cv = AnyEvent->condvar;	714	my $cv = AnyEvent->condvar;
551		715
		716	$cv->begin; # first watcher
		717	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		718	defined sysread $fh1, my $buf, 4096
		719	or $cv->end;
		720	});
		721
		722	$cv->begin; # second watcher
		723	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		724	defined sysread $fh2, my $buf, 4096
		725	or $cv->end;
		726	});
		727
		728	$cv->recv;
		729
		730	This works because for every event source (EOF on file handle), there is
		731	one call to C<begin>, so the condvar waits for all calls to C<end> before
		732	sending.
		733
		734	The ping example mentioned above is slightly more complicated, as the
		735	there are results to be passwd back, and the number of tasks that are
		736	begung can potentially be zero:
		737
		738	my $cv = AnyEvent->condvar;
		739
552	my %result;	740	my %result;
553	$cv->begin (sub { $cv->send (\%result) });	741	$cv->begin (sub { shift->send (\%result) });
554		742
555	for my $host (@list_of_hosts) {	743	for my $host (@list_of_hosts) {
556	$cv->begin;	744	$cv->begin;
557	ping_host_then_call_callback $host, sub {	745	ping_host_then_call_callback $host, sub {
558	$result{$host} = ...;	746	$result{$host} = ...;
…		…
573	loop, which serves two important purposes: first, it sets the callback	761	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	762	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	763	C<send> is called even when C<no> hosts are being pinged (the loop
576	doesn't execute once).	764	doesn't execute once).
577		765
578	This is the general pattern when you "fan out" into multiple subrequests:	766	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>	767	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	768	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>.	769	subrequest you start, call C<begin> and for each subrequest you finish,
		770	call C<end>.
582		771
583	=back	772	=back
584		773
585	=head3 METHODS FOR CONSUMERS	774	=head3 METHODS FOR CONSUMERS
586		775
…		…
602	function will call C<croak>.	791	function will call C<croak>.
603		792
604	In list context, all parameters passed to C<send> will be returned,	793	In list context, all parameters passed to C<send> will be returned,
605	in scalar context only the first one will be returned.	794	in scalar context only the first one will be returned.
606		795
		796	Note that doing a blocking wait in a callback is not supported by any
		797	event loop, that is, recursive invocation of a blocking C<< ->recv
		798	>> is not allowed, and the C<recv> call will C<croak> if such a
		799	condition is detected. This condition can be slightly loosened by using
		800	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		801	any thread that doesn't run the event loop itself.
		802
607	Not all event models support a blocking wait - some die in that case	803	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	804	(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	805	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	806	caller decide whether the call will block or not (for example, by coupling
611	condition variables with some kind of request results and supporting	807	condition variables with some kind of request results and supporting
612	callbacks so the caller knows that getting the result will not block,	808	callbacks so the caller knows that getting the result will not block,
613	while still supporting blocking waits if the caller so desires).	809	while still supporting blocking waits if the caller so desires).
614		810
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	811	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	812	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	813	time). This will work even when the event loop does not support blocking
629	waits otherwise.	814	waits otherwise.
630		815
…		…
636	=item $cb = $cv->cb ($cb->($cv))	821	=item $cb = $cv->cb ($cb->($cv))
637		822
638	This is a mutator function that returns the callback set and optionally	823	This is a mutator function that returns the callback set and optionally
639	replaces it before doing so.	824	replaces it before doing so.
640		825
641	The callback will be called when the condition becomes "true", i.e. when	826	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	827	"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	828	the only argument being the condition variable itself. Calling C<recv>
644	is guaranteed not to block.	829	inside the callback or at any later time is guaranteed not to block.
645		830
646	=back	831	=back
647		832
		833	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		834
		835	The available backend classes are (every class has its own manpage):
		836
		837	=over 4
		838
		839	=item Backends that are autoprobed when no other event loop can be found.
		840
		841	EV is the preferred backend when no other event loop seems to be in
		842	use. If EV is not installed, then AnyEvent will fall back to its own
		843	pure-perl implementation, which is available everywhere as it comes with
		844	AnyEvent itself.
		845
		846	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		847	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		848
		849	=item Backends that are transparently being picked up when they are used.
		850
		851	These will be used when they are currently loaded when the first watcher
		852	is created, in which case it is assumed that the application is using
		853	them. This means that AnyEvent will automatically pick the right backend
		854	when the main program loads an event module before anything starts to
		855	create watchers. Nothing special needs to be done by the main program.
		856
		857	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		858	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		859	AnyEvent::Impl::Tk based on Tk, very broken.
		860	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		861	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		862	AnyEvent::Impl::Irssi used when running within irssi.
		863
		864	=item Backends with special needs.
		865
		866	Qt requires the Qt::Application to be instantiated first, but will
		867	otherwise be picked up automatically. As long as the main program
		868	instantiates the application before any AnyEvent watchers are created,
		869	everything should just work.
		870
		871	AnyEvent::Impl::Qt based on Qt.
		872
		873	Support for IO::Async can only be partial, as it is too broken and
		874	architecturally limited to even support the AnyEvent API. It also
		875	is the only event loop that needs the loop to be set explicitly, so
		876	it can only be used by a main program knowing about AnyEvent. See
		877	L<AnyEvent::Impl::Async> for the gory details.
		878
		879	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		880
		881	=item Event loops that are indirectly supported via other backends.
		882
		883	Some event loops can be supported via other modules:
		884
		885	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		886
		887	B<WxWidgets> has no support for watching file handles. However, you can
		888	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		889	polls 20 times per second, which was considered to be too horrible to even
		890	consider for AnyEvent.
		891
		892	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		893	backend, so it can be supported through POE.
		894
		895	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		896	load L<POE> when detecting them, in the hope that POE will pick them up,
		897	in which case everything will be automatic.
		898
		899	=back
		900
648	=head1 GLOBAL VARIABLES AND FUNCTIONS	901	=head1 GLOBAL VARIABLES AND FUNCTIONS
649		902
		903	These are not normally required to use AnyEvent, but can be useful to
		904	write AnyEvent extension modules.
		905
650	=over 4	906	=over 4
651		907
652	=item $AnyEvent::MODEL	908	=item $AnyEvent::MODEL
653		909
654	Contains C<undef> until the first watcher is being created. Then it	910	Contains C<undef> until the first watcher is being created, before the
		911	backend has been autodetected.
		912
655	contains the event model that is being used, which is the name of the	913	Afterwards it contains the event model that is being used, which is the
656	Perl class implementing the model. This class is usually one of the	914	name of the Perl class implementing the model. This class is usually one
657	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	915	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
658	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	916	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
659		917	will be C<urxvt::anyevent>).
660	The known classes so far are:
661
662	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
663	AnyEvent::Impl::Event based on Event, second best choice.
664	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
665	AnyEvent::Impl::Glib based on Glib, third-best choice.
666	AnyEvent::Impl::Tk based on Tk, very bad choice.
667	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
668	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
669	AnyEvent::Impl::POE based on POE, not generic enough for full support.
670
671	There is no support for WxWidgets, as WxWidgets has no support for
672	watching file handles. However, you can use WxWidgets through the
673	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
674	second, which was considered to be too horrible to even consider for
675	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
676	it's adaptor.
677
678	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
679	autodetecting them.
680		918
681	=item AnyEvent::detect	919	=item AnyEvent::detect
682		920
683	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	921	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
684	if necessary. You should only call this function right before you would	922	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	923	have created an AnyEvent watcher anyway, that is, as late as possible at
686	runtime.	924	runtime, and not e.g. while initialising of your module.
		925
		926	If you need to do some initialisation before AnyEvent watchers are
		927	created, use C<post_detect>.
687		928
688	=item $guard = AnyEvent::post_detect { BLOCK }	929	=item $guard = AnyEvent::post_detect { BLOCK }
689		930
690	Arranges for the code block to be executed as soon as the event model is	931	Arranges for the code block to be executed as soon as the event model is
691	autodetected (or immediately if this has already happened).	932	autodetected (or immediately if this has already happened).
692		933
		934	The block will be executed I<after> the actual backend has been detected
		935	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		936	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		937	other initialisations - see the sources of L<AnyEvent::Strict> or
		938	L<AnyEvent::AIO> to see how this is used.
		939
		940	The most common usage is to create some global watchers, without forcing
		941	event module detection too early, for example, L<AnyEvent::AIO> creates
		942	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		943	avoid autodetecting the event module at load time.
		944
693	If called in scalar or list context, then it creates and returns an object	945	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	946	that automatically removes the callback again when it is destroyed (or
		947	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
695	L<Coro::BDB> for a case where this is useful.	948	a case where this is useful.
		949
		950	Example: Create a watcher for the IO::AIO module and store it in
		951	C<$WATCHER>. Only do so after the event loop is initialised, though.
		952
		953	our WATCHER;
		954
		955	my $guard = AnyEvent::post_detect {
		956	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		957	};
		958
		959	# the ||= is important in case post_detect immediately runs the block,
		960	# as to not clobber the newly-created watcher. assigning both watcher and
		961	# post_detect guard to the same variable has the advantage of users being
		962	# able to just C<undef $WATCHER> if the watcher causes them grief.
		963
		964	$WATCHER ||= $guard;
696		965
697	=item @AnyEvent::post_detect	966	=item @AnyEvent::post_detect
698		967
699	If there are any code references in this array (you can C<push> to it	968	If there are any code references in this array (you can C<push> to it
700	before or after loading AnyEvent), then they will called directly after	969	before or after loading AnyEvent), then they will called directly after
701	the event loop has been chosen.	970	the event loop has been chosen.
702		971
703	You should check C<$AnyEvent::MODEL> before adding to this array, though:	972	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,	973	if it is defined then the event loop has already been detected, and the
705	and the array will be ignored.	974	array will be ignored.
706		975
707	Best use C<AnyEvent::post_detect { BLOCK }> instead.	976	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		977	it, as it takes care of these details.
		978
		979	This variable is mainly useful for modules that can do something useful
		980	when AnyEvent is used and thus want to know when it is initialised, but do
		981	not need to even load it by default. This array provides the means to hook
		982	into AnyEvent passively, without loading it.
		983
		984	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		985	together, you could put this into Coro (this is the actual code used by
		986	Coro to accomplish this):
		987
		988	if (defined $AnyEvent::MODEL) {
		989	# AnyEvent already initialised, so load Coro::AnyEvent
		990	require Coro::AnyEvent;
		991	} else {
		992	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		993	# as soon as it is
		994	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		995	}
708		996
709	=back	997	=back
710		998
711	=head1 WHAT TO DO IN A MODULE	999	=head1 WHAT TO DO IN A MODULE
712		1000
…		…
767		1055
768		1056
769	=head1 OTHER MODULES	1057	=head1 OTHER MODULES
770		1058
771	The following is a non-exhaustive list of additional modules that use	1059	The following is a non-exhaustive list of additional modules that use
772	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1060	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	1061	modules and other event loops in the same program. Some of the modules
774	available via CPAN.	1062	come with AnyEvent, most are available via CPAN.
775		1063
776	=over 4	1064	=over 4
777		1065
778	=item L<AnyEvent::Util>	1066	=item L<AnyEvent::Util>
779		1067
…		…
788		1076
789	=item L<AnyEvent::Handle>	1077	=item L<AnyEvent::Handle>
790		1078
791	Provide read and write buffers, manages watchers for reads and writes,	1079	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	1080	supports raw and formatted I/O, I/O queued and fully transparent and
793	non-blocking SSL/TLS.	1081	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
794		1082
795	=item L<AnyEvent::DNS>	1083	=item L<AnyEvent::DNS>
796		1084
797	Provides rich asynchronous DNS resolver capabilities.	1085	Provides rich asynchronous DNS resolver capabilities.
798		1086
…		…
826		1114
827	=item L<AnyEvent::GPSD>	1115	=item L<AnyEvent::GPSD>
828		1116
829	A non-blocking interface to gpsd, a daemon delivering GPS information.	1117	A non-blocking interface to gpsd, a daemon delivering GPS information.
830		1118
		1119	=item L<AnyEvent::IRC>
		1120
		1121	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1122
		1123	=item L<AnyEvent::XMPP>
		1124
		1125	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1126	Net::XMPP2>.
		1127
831	=item L<AnyEvent::IGS>	1128	=item L<AnyEvent::IGS>
832		1129
833	A non-blocking interface to the Internet Go Server protocol (used by	1130	A non-blocking interface to the Internet Go Server protocol (used by
834	L<App::IGS>).	1131	L<App::IGS>).
835		1132
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>	1133	=item L<Net::FCP>
845		1134
846	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1135	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
847	of AnyEvent.	1136	of AnyEvent.
848		1137
…		…
852		1141
853	=item L<Coro>	1142	=item L<Coro>
854		1143
855	Has special support for AnyEvent via L<Coro::AnyEvent>.	1144	Has special support for AnyEvent via L<Coro::AnyEvent>.
856		1145
857	=item L<IO::Lambda>
858
859	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
860
861	=back	1146	=back
862		1147
863	=cut	1148	=cut
864		1149
865	package AnyEvent;	1150	package AnyEvent;
866		1151
867	no warnings;	1152	# basically a tuned-down version of common::sense
868	use strict qw(vars subs);	1153	sub common_sense {
		1154	# from common:.sense 1.0
		1155	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
		1156	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1157	$^H |= 0x00000600;
		1158	}
869		1159
		1160	BEGIN { AnyEvent::common_sense }
		1161
870	use Carp;	1162	use Carp ();
871		1163
872	our $VERSION = 4.341;	1164	our $VERSION = '5.26';
873	our $MODEL;	1165	our $MODEL;
874		1166
875	our $AUTOLOAD;	1167	our $AUTOLOAD;
876	our @ISA;	1168	our @ISA;
877		1169
878	our @REGISTRY;	1170	our @REGISTRY;
879		1171
880	our $WIN32;	1172	our $VERBOSE;
881		1173
882	BEGIN {	1174	BEGIN {
883	my $win32 = ! ! ($^O =~ /mswin32/i);	1175	require "AnyEvent/constants.pl";
884	eval "sub WIN32(){ $win32 }";
885	}
886		1176
		1177	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
		1178
		1179	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1180	if ${^TAINT};
		1181
887	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1182	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1183
		1184	}
		1185
		1186	our $MAX_SIGNAL_LATENCY = 10;
888		1187
889	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1188	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
890		1189
891	{	1190	{
892	my $idx;	1191	my $idx;
…		…
894	for reverse split /\s*,\s*/,	1193	for reverse split /\s*,\s*/,
895	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1194	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
896	}	1195	}
897		1196
898	my @models = (	1197	my @models = (
899	[EV:: => AnyEvent::Impl::EV::],	1198	[EV:: => AnyEvent::Impl::EV:: , 1],
900	[Event:: => AnyEvent::Impl::Event::],
901	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1199	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
902	# everything below here will not be autoprobed	1200	# everything below here will not (normally) be autoprobed
903	# as the pureperl backend should work everywhere	1201	# as the pureperl backend should work everywhere
904	# and is usually faster	1202	# and is usually faster
		1203	[Event:: => AnyEvent::Impl::Event::, 1],
		1204	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1205	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1206	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
905	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1207	[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	1208	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
909	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1209	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
910	[Wx:: => AnyEvent::Impl::POE::],	1210	[Wx:: => AnyEvent::Impl::POE::],
911	[Prima:: => AnyEvent::Impl::POE::],	1211	[Prima:: => AnyEvent::Impl::POE::],
		1212	# IO::Async is just too broken - we would need workarounds for its
		1213	# byzantine signal and broken child handling, among others.
		1214	# IO::Async is rather hard to detect, as it doesn't have any
		1215	# obvious default class.
		1216	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1217	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1218	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1219	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
912	);	1220	);
913		1221
914	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1222	our %method = map +($_ => 1),
		1223	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
915		1224
916	our @post_detect;	1225	our @post_detect;
917		1226
918	sub post_detect(&) {	1227	sub post_detect(&) {
919	my ($cb) = @_;	1228	my ($cb) = @_;
920		1229
921	if ($MODEL) {
922	$cb->();
923
924	1
925	} else {
926	push @post_detect, $cb;	1230	push @post_detect, $cb;
927		1231
928	defined wantarray	1232	defined wantarray
929	? bless \$cb, "AnyEvent::Util::PostDetect"	1233	? bless \$cb, "AnyEvent::Util::postdetect"
930	: ()	1234	: ()
		1235	}
		1236
		1237	sub AnyEvent::Util::postdetect::DESTROY {
		1238	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1239	}
		1240
		1241	sub detect() {
		1242	# free some memory
		1243	*detect = sub () { $MODEL };
		1244
		1245	local $!; # for good measure
		1246	local $SIG{__DIE__};
		1247
		1248	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1249	my $model = "AnyEvent::Impl::$1";
		1250	if (eval "require $model") {
		1251	$MODEL = $model;
		1252	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1253	} else {
		1254	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1255	}
931	}	1256	}
932	}
933		1257
934	sub AnyEvent::Util::PostDetect::DESTROY {	1258	# check for already loaded models
935	@post_detect = grep $_ != ${$_[0]}, @post_detect;
936	}
937
938	sub detect() {
939	unless ($MODEL) {	1259	unless ($MODEL) {
940	no strict 'refs';	1260	for (@REGISTRY, @models) {
941	local $SIG{__DIE__};	1261	my ($package, $model) = @$_;
942		1262	if (${"$package\::VERSION"} > 0) {
943	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
944	my $model = "AnyEvent::Impl::$1";
945	if (eval "require $model") {	1263	if (eval "require $model") {
946	$MODEL = $model;	1264	$MODEL = $model;
947	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1265	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
948	} else {	1266	last;
949	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1267	}
950	}	1268	}
951	}	1269	}
952		1270
953	# check for already loaded models
954	unless ($MODEL) {	1271	unless ($MODEL) {
		1272	# try to autoload a model
955	for (@REGISTRY, @models) {	1273	for (@REGISTRY, @models) {
956	my ($package, $model) = @$_;	1274	my ($package, $model, $autoload) = @$_;
		1275	if (
		1276	$autoload
		1277	and eval "require $package"
957	if (${"$package\::VERSION"} > 0) {	1278	and ${"$package\::VERSION"} > 0
958	if (eval "require $model") {	1279	and eval "require $model"
		1280	) {
959	$MODEL = $model;	1281	$MODEL = $model;
960	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1282	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
961	last;	1283	last;
962	}
963	}	1284	}
964	}	1285	}
965		1286
966	unless ($MODEL) {
967	# try to load a model
968
969	for (@REGISTRY, @models) {
970	my ($package, $model) = @$_;
971	if (eval "require $package"
972	and ${"$package\::VERSION"} > 0
973	and eval "require $model") {
974	$MODEL = $model;
975	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
976	last;
977	}
978	}
979
980	$MODEL	1287	$MODEL
981	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1288	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
982	}
983	}	1289	}
984
985	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
986
987	unshift @ISA, $MODEL;
988
989	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
990
991	(shift @post_detect)->() while @post_detect;
992	}	1290	}
		1291
		1292	@models = (); # free probe data
		1293
		1294	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1295	unshift @ISA, $MODEL;
		1296
		1297	# now nuke some methods that are overriden by the backend.
		1298	# SUPER is not allowed.
		1299	for (qw(time signal child idle)) {
		1300	undef &{"AnyEvent::Base::$_"}
		1301	if defined &{"$MODEL\::$_"};
		1302	}
		1303
		1304	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1305
		1306	(shift @post_detect)->() while @post_detect;
		1307
		1308	*post_detect = sub(&) {
		1309	shift->();
		1310
		1311	undef
		1312	};
993		1313
994	$MODEL	1314	$MODEL
995	}	1315	}
996		1316
997	sub AUTOLOAD {	1317	sub AUTOLOAD {
998	(my $func = $AUTOLOAD) =~ s/.*://;	1318	(my $func = $AUTOLOAD) =~ s/.*://;
999		1319
1000	$method{$func}	1320	$method{$func}
1001	or croak "$func: not a valid method for AnyEvent objects";	1321	or Carp::croak "$func: not a valid AnyEvent class method";
1002		1322
1003	detect unless $MODEL;	1323	detect;
1004		1324
1005	my $class = shift;	1325	my $class = shift;
1006	$class->$func (@_);	1326	$class->$func (@_);
1007	}	1327	}
1008		1328
1009	# utility function to dup a filehandle. this is used by many backends	1329	# utility function to dup a filehandle. this is used by many backends
1010	# to support binding more than one watcher per filehandle (they usually	1330	# 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).	1331	# allow only one watcher per fd, so we dup it to get a different one).
1012	sub _dupfh($$$$) {	1332	sub _dupfh($$;$$) {
1013	my ($poll, $fh, $r, $w) = @_;	1333	my ($poll, $fh, $r, $w) = @_;
1014		1334
1015	# cygwin requires the fh mode to be matching, unix doesn't	1335	# cygwin requires the fh mode to be matching, unix doesn't
1016	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1336	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1017	: $poll eq "w" ? ($w, ">")
1018	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1019		1337
1020	open my $fh2, "$mode&" . fileno $fh	1338	open my $fh2, $mode, $fh
1021	or die "cannot dup() filehandle: $!";	1339	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1022		1340
1023	# we assume CLOEXEC is already set by perl in all important cases	1341	# we assume CLOEXEC is already set by perl in all important cases
1024		1342
1025	($fh2, $rw)	1343	($fh2, $rw)
1026	}	1344	}
1027		1345
		1346	=head1 SIMPLIFIED AE API
		1347
		1348	Starting with version 5.0, AnyEvent officially supports a second, much
		1349	simpler, API that is designed to reduce the calling, typing and memory
		1350	overhead by using function call syntax and a fixed number of parameters.
		1351
		1352	See the L<AE> manpage for details.
		1353
		1354	=cut
		1355
		1356	package AE;
		1357
		1358	our $VERSION = $AnyEvent::VERSION;
		1359
		1360	# fall back to the main API by default - backends and AnyEvent::Base
		1361	# implementations can overwrite these.
		1362
		1363	sub io($$$) {
		1364	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1365	}
		1366
		1367	sub timer($$$) {
		1368	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1369	}
		1370
		1371	sub signal($$) {
		1372	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1373	}
		1374
		1375	sub child($$) {
		1376	AnyEvent->child (pid => $_[0], cb => $_[1])
		1377	}
		1378
		1379	sub idle($) {
		1380	AnyEvent->idle (cb => $_[0])
		1381	}
		1382
		1383	sub cv(;&) {
		1384	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1385	}
		1386
		1387	sub now() {
		1388	AnyEvent->now
		1389	}
		1390
		1391	sub now_update() {
		1392	AnyEvent->now_update
		1393	}
		1394
		1395	sub time() {
		1396	AnyEvent->time
		1397	}
		1398
1028	package AnyEvent::Base;	1399	package AnyEvent::Base;
1029		1400
1030	# default implementation for now and time	1401	# default implementations for many methods
1031		1402
1032	BEGIN {	1403	sub time {
		1404	eval q{ # poor man's autoloading {}
		1405	# probe for availability of Time::HiRes
1033	if (eval "use Time::HiRes (); time (); 1") {	1406	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1407	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1034	*_time = \&Time::HiRes::time;	1408	*AE::time = \&Time::HiRes::time;
1035	# if (eval "use POSIX (); (POSIX::times())...	1409	# if (eval "use POSIX (); (POSIX::times())...
1036	} else {	1410	} else {
		1411	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1037	*_time = sub { time }; # epic fail	1412	*AE::time = sub (){ time }; # epic fail
		1413	}
		1414
		1415	*time = sub { AE::time }; # different prototypes
		1416	};
		1417	die if $@;
		1418
		1419	&time
		1420	}
		1421
		1422	*now = \&time;
		1423
		1424	sub now_update { }
		1425
		1426	# default implementation for ->condvar
		1427
		1428	sub condvar {
		1429	eval q{ # poor man's autoloading {}
		1430	*condvar = sub {
		1431	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1432	};
		1433
		1434	*AE::cv = sub (;&) {
		1435	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1436	};
		1437	};
		1438	die if $@;
		1439
		1440	&condvar
		1441	}
		1442
		1443	# default implementation for ->signal
		1444
		1445	our $HAVE_ASYNC_INTERRUPT;
		1446
		1447	sub _have_async_interrupt() {
		1448	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1449	&& eval "use Async::Interrupt 1.02 (); 1")
		1450	unless defined $HAVE_ASYNC_INTERRUPT;
		1451
		1452	$HAVE_ASYNC_INTERRUPT
		1453	}
		1454
		1455	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1456	our (%SIG_ASY, %SIG_ASY_W);
		1457	our ($SIG_COUNT, $SIG_TW);
		1458
		1459	# install a dummy wakeup watcher to reduce signal catching latency
		1460	# used by Impls
		1461	sub _sig_add() {
		1462	unless ($SIG_COUNT++) {
		1463	# try to align timer on a full-second boundary, if possible
		1464	my $NOW = AE::now;
		1465
		1466	$SIG_TW = AE::timer
		1467	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1468	$MAX_SIGNAL_LATENCY,
		1469	sub { } # just for the PERL_ASYNC_CHECK
		1470	;
1038	}	1471	}
1039	}	1472	}
1040		1473
1041	sub time { _time }	1474	sub _sig_del {
1042	sub now { _time }	1475	undef $SIG_TW
1043		1476	unless --$SIG_COUNT;
1044	# default implementation for ->condvar
1045
1046	sub condvar {
1047	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
1048	}	1477	}
1049		1478
1050	# default implementation for ->signal	1479	our $_sig_name_init; $_sig_name_init = sub {
		1480	eval q{ # poor man's autoloading {}
		1481	undef $_sig_name_init;
1051		1482
1052	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1483	if (_have_async_interrupt) {
		1484	*sig2num = \&Async::Interrupt::sig2num;
		1485	*sig2name = \&Async::Interrupt::sig2name;
		1486	} else {
		1487	require Config;
1053		1488
1054	sub _signal_exec {	1489	my %signame2num;
1055	sysread $SIGPIPE_R, my $dummy, 4;	1490	@signame2num{ split ' ', $Config::Config{sig_name} }
		1491	= split ' ', $Config::Config{sig_num};
1056		1492
1057	while (%SIG_EV) {	1493	my @signum2name;
1058	for (keys %SIG_EV) {	1494	@signum2name[values %signame2num] = keys %signame2num;
1059	delete $SIG_EV{$_};	1495
1060	$_->() for values %{ $SIG_CB{$_} || {} };	1496	*sig2num = sub($) {
		1497	$_[0] > 0 ? shift : $signame2num{+shift}
		1498	};
		1499	*sig2name = sub ($) {
		1500	$_[0] > 0 ? $signum2name[+shift] : shift
		1501	};
1061	}	1502	}
1062	}	1503	};
1063	}	1504	die if $@;
		1505	};
		1506
		1507	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1508	sub sig2name($) { &$_sig_name_init; &sig2name }
1064		1509
1065	sub signal {	1510	sub signal {
1066	my (undef, %arg) = @_;	1511	eval q{ # poor man's autoloading {}
		1512	# probe for availability of Async::Interrupt
		1513	if (_have_async_interrupt) {
		1514	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1067		1515
1068	unless ($SIGPIPE_R) {	1516	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1069	if (AnyEvent::WIN32) {	1517	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1070	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();	1518
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 {	1519	} else {
		1520	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1521
		1522	if (AnyEvent::WIN32) {
		1523	require AnyEvent::Util;
		1524
		1525	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1526	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1527	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1528	} else {
1074	pipe $SIGPIPE_R, $SIGPIPE_W;	1529	pipe $SIGPIPE_R, $SIGPIPE_W;
1075	require Fcntl;
1076	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1530	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1077	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1531	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1532
		1533	# not strictly required, as $^F is normally 2, but let's make sure...
		1534	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1535	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1536	}
		1537
		1538	$SIGPIPE_R
		1539	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1540
		1541	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1078	}	1542	}
1079		1543
1080	$SIGPIPE_R	1544	*signal = $HAVE_ASYNC_INTERRUPT
1081	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1545	? sub {
		1546	my (undef, %arg) = @_;
1082		1547
1083	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1548	# async::interrupt
1084	}
1085
1086	my $signal = uc $arg{signal}	1549	my $signal = sig2num $arg{signal};
1087	or Carp::croak "required option 'signal' is missing";
1088
1089	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1550	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1551
		1552	$SIG_ASY{$signal} ||= new Async::Interrupt
		1553	cb => sub { undef $SIG_EV{$signal} },
		1554	signal => $signal,
		1555	pipe => [$SIGPIPE_R->filenos],
		1556	pipe_autodrain => 0,
		1557	;
		1558
		1559	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1560	}
		1561	: sub {
		1562	my (undef, %arg) = @_;
		1563
		1564	# pure perl
		1565	my $signal = sig2name $arg{signal};
		1566	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1567
1090	$SIG{$signal} ||= sub {	1568	$SIG{$signal} ||= sub {
		1569	local $!;
1091	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1570	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1092	undef $SIG_EV{$signal};	1571	undef $SIG_EV{$signal};
		1572	};
		1573
		1574	# can't do signal processing without introducing races in pure perl,
		1575	# so limit the signal latency.
		1576	_sig_add;
		1577
		1578	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1579	}
		1580	;
		1581
		1582	*AnyEvent::Base::signal::DESTROY = sub {
		1583	my ($signal, $cb) = @{$_[0]};
		1584
		1585	_sig_del;
		1586
		1587	delete $SIG_CB{$signal}{$cb};
		1588
		1589	$HAVE_ASYNC_INTERRUPT
		1590	? delete $SIG_ASY{$signal}
		1591	: # delete doesn't work with older perls - they then
		1592	# print weird messages, or just unconditionally exit
		1593	# instead of getting the default action.
		1594	undef $SIG{$signal}
		1595	unless keys %{ $SIG_CB{$signal} };
		1596	};
		1597
		1598	*_signal_exec = sub {
		1599	$HAVE_ASYNC_INTERRUPT
		1600	? $SIGPIPE_R->drain
		1601	: sysread $SIGPIPE_R, (my $dummy), 9;
		1602
		1603	while (%SIG_EV) {
		1604	for (keys %SIG_EV) {
		1605	delete $SIG_EV{$_};
		1606	$_->() for values %{ $SIG_CB{$_} || {} };
		1607	}
		1608	}
		1609	};
1093	};	1610	};
		1611	die if $@;
1094		1612
1095	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1613	&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	}	1614	}
1105		1615
1106	# default implementation for ->child	1616	# default implementation for ->child
1107		1617
1108	our %PID_CB;	1618	our %PID_CB;
1109	our $CHLD_W;	1619	our $CHLD_W;
1110	our $CHLD_DELAY_W;	1620	our $CHLD_DELAY_W;
1111	our $PID_IDLE;
1112	our $WNOHANG;	1621	our $WNOHANG;
1113		1622
1114	sub _child_wait {	1623	# used by many Impl's
1115	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1624	sub _emit_childstatus($$) {
		1625	my (undef, $rpid, $rstatus) = @_;
		1626
		1627	$_->($rpid, $rstatus)
1116	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1628	for values %{ $PID_CB{$rpid} || {} },
1117	(values %{ $PID_CB{0} || {} });	1629	values %{ $PID_CB{0} || {} };
1118	}
1119
1120	undef $PID_IDLE;
1121	}
1122
1123	sub _sigchld {
1124	# make sure we deliver these changes "synchronous" with the event loop.
1125	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
1126	undef $CHLD_DELAY_W;
1127	&_child_wait;
1128	});
1129	}	1630	}
1130		1631
1131	sub child {	1632	sub child {
		1633	eval q{ # poor man's autoloading {}
		1634	*_sigchld = sub {
		1635	my $pid;
		1636
		1637	AnyEvent->_emit_childstatus ($pid, $?)
		1638	while ($pid = waitpid -1, $WNOHANG) > 0;
		1639	};
		1640
		1641	*child = sub {
1132	my (undef, %arg) = @_;	1642	my (undef, %arg) = @_;
1133		1643
1134	defined (my $pid = $arg{pid} + 0)	1644	defined (my $pid = $arg{pid} + 0)
1135	or Carp::croak "required option 'pid' is missing";	1645	or Carp::croak "required option 'pid' is missing";
1136		1646
1137	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1647	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1138		1648
1139	unless ($WNOHANG) {	1649	# WNOHANG is almost cetrainly 1 everywhere
		1650	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1651	? 1
1140	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1652	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1141	}
1142		1653
1143	unless ($CHLD_W) {	1654	unless ($CHLD_W) {
1144	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1655	$CHLD_W = AE::signal CHLD => \&_sigchld;
1145	# child could be a zombie already, so make at least one round	1656	# child could be a zombie already, so make at least one round
1146	&_sigchld;	1657	&_sigchld;
1147	}	1658	}
1148		1659
1149	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1660	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1150	}	1661	};
1151		1662
1152	sub AnyEvent::Base::Child::DESTROY {	1663	*AnyEvent::Base::child::DESTROY = sub {
1153	my ($pid, $cb) = @{$_[0]};	1664	my ($pid, $cb) = @{$_[0]};
1154		1665
1155	delete $PID_CB{$pid}{$cb};	1666	delete $PID_CB{$pid}{$cb};
1156	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1667	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1157		1668
1158	undef $CHLD_W unless keys %PID_CB;	1669	undef $CHLD_W unless keys %PID_CB;
		1670	};
		1671	};
		1672	die if $@;
		1673
		1674	&child
		1675	}
		1676
		1677	# idle emulation is done by simply using a timer, regardless
		1678	# of whether the process is idle or not, and not letting
		1679	# the callback use more than 50% of the time.
		1680	sub idle {
		1681	eval q{ # poor man's autoloading {}
		1682	*idle = sub {
		1683	my (undef, %arg) = @_;
		1684
		1685	my ($cb, $w, $rcb) = $arg{cb};
		1686
		1687	$rcb = sub {
		1688	if ($cb) {
		1689	$w = _time;
		1690	&$cb;
		1691	$w = _time - $w;
		1692
		1693	# never use more then 50% of the time for the idle watcher,
		1694	# within some limits
		1695	$w = 0.0001 if $w < 0.0001;
		1696	$w = 5 if $w > 5;
		1697
		1698	$w = AE::timer $w, 0, $rcb;
		1699	} else {
		1700	# clean up...
		1701	undef $w;
		1702	undef $rcb;
		1703	}
		1704	};
		1705
		1706	$w = AE::timer 0.05, 0, $rcb;
		1707
		1708	bless \\$cb, "AnyEvent::Base::idle"
		1709	};
		1710
		1711	*AnyEvent::Base::idle::DESTROY = sub {
		1712	undef $${$_[0]};
		1713	};
		1714	};
		1715	die if $@;
		1716
		1717	&idle
1159	}	1718	}
1160		1719
1161	package AnyEvent::CondVar;	1720	package AnyEvent::CondVar;
1162		1721
1163	our @ISA = AnyEvent::CondVar::Base::;	1722	our @ISA = AnyEvent::CondVar::Base::;
1164		1723
1165	package AnyEvent::CondVar::Base;	1724	package AnyEvent::CondVar::Base;
1166		1725
1167	use overload	1726	#use overload
1168	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1727	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1169	fallback => 1;	1728	# fallback => 1;
		1729
		1730	# save 300+ kilobytes by dirtily hardcoding overloading
		1731	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1732	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1733	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1734	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1735
		1736	our $WAITING;
1170		1737
1171	sub _send {	1738	sub _send {
1172	# nop	1739	# nop
1173	}	1740	}
1174		1741
…		…
1187	sub ready {	1754	sub ready {
1188	$_[0]{_ae_sent}	1755	$_[0]{_ae_sent}
1189	}	1756	}
1190		1757
1191	sub _wait {	1758	sub _wait {
		1759	$WAITING
		1760	and !$_[0]{_ae_sent}
		1761	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1762
		1763	local $WAITING = 1;
1192	AnyEvent->one_event while !$_[0]{_ae_sent};	1764	AnyEvent->one_event while !$_[0]{_ae_sent};
1193	}	1765	}
1194		1766
1195	sub recv {	1767	sub recv {
1196	$_[0]->_wait;	1768	$_[0]->_wait;
…		…
1198	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1770	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1199	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1771	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1200	}	1772	}
1201		1773
1202	sub cb {	1774	sub cb {
1203	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1775	my $cv = shift;
		1776
		1777	@_
		1778	and $cv->{_ae_cb} = shift
		1779	and $cv->{_ae_sent}
		1780	and (delete $cv->{_ae_cb})->($cv);
		1781
1204	$_[0]{_ae_cb}	1782	$cv->{_ae_cb}
1205	}	1783	}
1206		1784
1207	sub begin {	1785	sub begin {
1208	++$_[0]{_ae_counter};	1786	++$_[0]{_ae_counter};
1209	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1787	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1237	so on.	1815	so on.
1238		1816
1239	=head1 ENVIRONMENT VARIABLES	1817	=head1 ENVIRONMENT VARIABLES
1240		1818
1241	The following environment variables are used by this module or its	1819	The following environment variables are used by this module or its
1242	submodules:	1820	submodules.
		1821
		1822	Note that AnyEvent will remove I<all> environment variables starting with
		1823	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1824	enabled.
1243		1825
1244	=over 4	1826	=over 4
1245		1827
1246	=item C<PERL_ANYEVENT_VERBOSE>	1828	=item C<PERL_ANYEVENT_VERBOSE>
1247		1829
…		…
1254	C<PERL_ANYEVENT_MODEL>.	1836	C<PERL_ANYEVENT_MODEL>.
1255		1837
1256	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1838	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1257	model it chooses.	1839	model it chooses.
1258		1840
		1841	When set to C<8> or higher, then AnyEvent will report extra information on
		1842	which optional modules it loads and how it implements certain features.
		1843
1259	=item C<PERL_ANYEVENT_STRICT>	1844	=item C<PERL_ANYEVENT_STRICT>
1260		1845
1261	AnyEvent does not do much argument checking by default, as thorough	1846	AnyEvent does not do much argument checking by default, as thorough
1262	argument checking is very costly. Setting this variable to a true value	1847	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	1848	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	1849	check the arguments passed to most method calls. If it finds any problems,
1265	it will croak.	1850	it will croak.
1266		1851
1267	In other words, enables "strict" mode.	1852	In other words, enables "strict" mode.
1268		1853
1269	Unlike C<use strict>, it is definitely recommended ot keep it off in	1854	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	1855	>>, it is definitely recommended to keep it off in production. Keeping
1271	developing programs can be very useful, however.	1856	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1857	can be very useful, however.
1272		1858
1273	=item C<PERL_ANYEVENT_MODEL>	1859	=item C<PERL_ANYEVENT_MODEL>
1274		1860
1275	This can be used to specify the event model to be used by AnyEvent, before	1861	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	1862	auto detection and -probing kicks in. It must be a string consisting
…		…
1319		1905
1320	=item C<PERL_ANYEVENT_MAX_FORKS>	1906	=item C<PERL_ANYEVENT_MAX_FORKS>
1321		1907
1322	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1908	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1323	will create in parallel.	1909	will create in parallel.
		1910
		1911	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1912
		1913	The default value for the C<max_outstanding> parameter for the default DNS
		1914	resolver - this is the maximum number of parallel DNS requests that are
		1915	sent to the DNS server.
		1916
		1917	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1918
		1919	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1920	configuration) in the default resolver. When set to the empty string, no
		1921	default config will be used.
		1922
		1923	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1924
		1925	When neither C<ca_file> nor C<ca_path> was specified during
		1926	L<AnyEvent::TLS> context creation, and either of these environment
		1927	variables exist, they will be used to specify CA certificate locations
		1928	instead of a system-dependent default.
		1929
		1930	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1931
		1932	When these are set to C<1>, then the respective modules are not
		1933	loaded. Mostly good for testing AnyEvent itself.
1324		1934
1325	=back	1935	=back
1326		1936
1327	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1937	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1328		1938
…		…
1386	warn "read: $input\n"; # output what has been read	1996	warn "read: $input\n"; # output what has been read
1387	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1997	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1388	},	1998	},
1389	);	1999	);
1390		2000
1391	my $time_watcher; # can only be used once
1392
1393	sub new_timer {
1394	$timer = AnyEvent->timer (after => 1, cb => sub {	2001	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1395	warn "timeout\n"; # print 'timeout' about every second	2002	warn "timeout\n"; # print 'timeout' at most every second
1396	&new_timer; # and restart the time
1397	});	2003	});
1398	}
1399
1400	new_timer; # create first timer
1401		2004
1402	$cv->recv; # wait until user enters /^q/i	2005	$cv->recv; # wait until user enters /^q/i
1403		2006
1404	=head1 REAL-WORLD EXAMPLE	2007	=head1 REAL-WORLD EXAMPLE
1405		2008
…		…
1478		2081
1479	The actual code goes further and collects all errors (C<die>s, exceptions)	2082	The actual code goes further and collects all errors (C<die>s, exceptions)
1480	that occurred during request processing. The C<result> method detects	2083	that occurred during request processing. The C<result> method detects
1481	whether an exception as thrown (it is stored inside the $txn object)	2084	whether an exception as thrown (it is stored inside the $txn object)
1482	and just throws the exception, which means connection errors and other	2085	and just throws the exception, which means connection errors and other
1483	problems get reported tot he code that tries to use the result, not in a	2086	problems get reported to the code that tries to use the result, not in a
1484	random callback.	2087	random callback.
1485		2088
1486	All of this enables the following usage styles:	2089	All of this enables the following usage styles:
1487		2090
1488	1. Blocking:	2091	1. Blocking:
…		…
1536	through AnyEvent. The benchmark creates a lot of timers (with a zero	2139	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,	2140	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.	2141	which it is), lets them fire exactly once and destroys them again.
1539		2142
1540	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2143	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1541	distribution.	2144	distribution. It uses the L<AE> interface, which makes a real difference
		2145	for the EV and Perl backends only.
1542		2146
1543	=head3 Explanation of the columns	2147	=head3 Explanation of the columns
1544		2148
1545	I<watcher> is the number of event watchers created/destroyed. Since	2149	I<watcher> is the number of event watchers created/destroyed. Since
1546	different event models feature vastly different performances, each event	2150	different event models feature vastly different performances, each event
…		…
1567	watcher.	2171	watcher.
1568		2172
1569	=head3 Results	2173	=head3 Results
1570		2174
1571	name watchers bytes create invoke destroy comment	2175	name watchers bytes create invoke destroy comment
1572	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2176	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	2177	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	2178	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	2179	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	2180	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	2181	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2182	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2183	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	2184	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	2185	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	2186	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	2187	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1582		2188
1583	=head3 Discussion	2189	=head3 Discussion
1584		2190
1585	The benchmark does I<not> measure scalability of the event loop very	2191	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)	2192	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	2204	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	2205	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1600	cycles with POE.	2206	cycles with POE.
1601		2207
1602	C<EV> is the sole leader regarding speed and memory use, which are both	2208	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	2209	maximal/minimal, respectively. When using the L<AE> API there is zero
		2210	overhead (when going through the AnyEvent API create is about 5-6 times
		2211	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	2212	any other event loop and is still faster than Event natively).
1605	natively.
1606		2213
1607	The pure perl implementation is hit in a few sweet spots (both the	2214	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	2215	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	2216	interpreter and the backend itself). Nevertheless this shows that it
1610	adds very little overhead in itself. Like any select-based backend its	2217	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	2218	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.	2219	them active), of course, but this was not subject of this benchmark.
1613		2220
1614	The C<Event> module has a relatively high setup and callback invocation	2221	The C<Event> module has a relatively high setup and callback invocation
1615	cost, but overall scores in on the third place.	2222	cost, but overall scores in on the third place.
		2223
		2224	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2225	when using its pure perl backend.
1616		2226
1617	C<Glib>'s memory usage is quite a bit higher, but it features a	2227	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	2228	faster callback invocation and overall ends up in the same class as
1619	C<Event>. However, Glib scales extremely badly, doubling the number of	2229	C<Event>. However, Glib scales extremely badly, doubling the number of
1620	watchers increases the processing time by more than a factor of four,	2230	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	2291	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	2292	(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.	2293	connections, most of which are idle at any one point in time.
1684		2294
1685	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2295	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1686	distribution.	2296	distribution. It uses the L<AE> interface, which makes a real difference
		2297	for the EV and Perl backends only.
1687		2298
1688	=head3 Explanation of the columns	2299	=head3 Explanation of the columns
1689		2300
1690	I<sockets> is the number of sockets, and twice the number of "servers" (as	2301	I<sockets> is the number of sockets, and twice the number of "servers" (as
1691	each server has a read and write socket end).	2302	each server has a read and write socket end).
…		…
1698	it to another server. This includes deleting the old timeout and creating	2309	it to another server. This includes deleting the old timeout and creating
1699	a new one that moves the timeout into the future.	2310	a new one that moves the timeout into the future.
1700		2311
1701	=head3 Results	2312	=head3 Results
1702		2313
1703	name sockets create request	2314	name sockets create request
1704	EV 20000 69.01 11.16	2315	EV 20000 62.66 7.99
1705	Perl 20000 73.32 35.87	2316	Perl 20000 68.32 32.64
1706	Event 20000 212.62 257.32	2317	IOAsync 20000 174.06 101.15 epoll
1707	Glib 20000 651.16 1896.30	2318	IOAsync 20000 174.67 610.84 poll
		2319	Event 20000 202.69 242.91
		2320	Glib 20000 557.01 1689.52
1708	POE 20000 349.67 12317.24 uses POE::Loop::Event	2321	POE 20000 341.54 12086.32 uses POE::Loop::Event
1709		2322
1710	=head3 Discussion	2323	=head3 Discussion
1711		2324
1712	This benchmark I<does> measure scalability and overall performance of the	2325	This benchmark I<does> measure scalability and overall performance of the
1713	particular event loop.	2326	particular event loop.
…		…
1715	EV is again fastest. Since it is using epoll on my system, the setup time	2328	EV is again fastest. Since it is using epoll on my system, the setup time
1716	is relatively high, though.	2329	is relatively high, though.
1717		2330
1718	Perl surprisingly comes second. It is much faster than the C-based event	2331	Perl surprisingly comes second. It is much faster than the C-based event
1719	loops Event and Glib.	2332	loops Event and Glib.
		2333
		2334	IO::Async performs very well when using its epoll backend, and still quite
		2335	good compared to Glib when using its pure perl backend.
1720		2336
1721	Event suffers from high setup time as well (look at its code and you will	2337	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	2338	understand why). Callback invocation also has a high overhead compared to
1723	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2339	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1724	uses select or poll in basically all documented configurations.	2340	uses select or poll in basically all documented configurations.
…		…
1787	=item * C-based event loops perform very well with small number of	2403	=item * C-based event loops perform very well with small number of
1788	watchers, as the management overhead dominates.	2404	watchers, as the management overhead dominates.
1789		2405
1790	=back	2406	=back
1791		2407
		2408	=head2 THE IO::Lambda BENCHMARK
		2409
		2410	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2411	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2412	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2413	shouldn't come as a surprise to anybody). As such, the benchmark is
		2414	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2415	very optimal. But how would AnyEvent compare when used without the extra
		2416	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2417
		2418	The benchmark itself creates an echo-server, and then, for 500 times,
		2419	connects to the echo server, sends a line, waits for the reply, and then
		2420	creates the next connection. This is a rather bad benchmark, as it doesn't
		2421	test the efficiency of the framework or much non-blocking I/O, but it is a
		2422	benchmark nevertheless.
		2423
		2424	name runtime
		2425	Lambda/select 0.330 sec
		2426	+ optimized 0.122 sec
		2427	Lambda/AnyEvent 0.327 sec
		2428	+ optimized 0.138 sec
		2429	Raw sockets/select 0.077 sec
		2430	POE/select, components 0.662 sec
		2431	POE/select, raw sockets 0.226 sec
		2432	POE/select, optimized 0.404 sec
		2433
		2434	AnyEvent/select/nb 0.085 sec
		2435	AnyEvent/EV/nb 0.068 sec
		2436	+state machine 0.134 sec
		2437
		2438	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2439	benchmarks actually make blocking connects and use 100% blocking I/O,
		2440	defeating the purpose of an event-based solution. All of the newly
		2441	written AnyEvent benchmarks use 100% non-blocking connects (using
		2442	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2443	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2444	generally require a lot more bookkeeping and event handling than blocking
		2445	connects (which involve a single syscall only).
		2446
		2447	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2448	offers similar expressive power as POE and IO::Lambda, using conventional
		2449	Perl syntax. This means that both the echo server and the client are 100%
		2450	non-blocking, further placing it at a disadvantage.
		2451
		2452	As you can see, the AnyEvent + EV combination even beats the
		2453	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2454	backend easily beats IO::Lambda and POE.
		2455
		2456	And even the 100% non-blocking version written using the high-level (and
		2457	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2458	higher level ("unoptimised") abstractions by a large margin, even though
		2459	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
		2460
		2461	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2462	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2463	part of the IO::Lambda distribution and were used without any changes.
		2464
1792		2465
1793	=head1 SIGNALS	2466	=head1 SIGNALS
1794		2467
1795	AnyEvent currently installs handlers for these signals:	2468	AnyEvent currently installs handlers for these signals:
1796		2469
…		…
1799	=item SIGCHLD	2472	=item SIGCHLD
1800		2473
1801	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2474	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	2475	emulation for event loops that do not support them natively. Also, some
1803	event loops install a similar handler.	2476	event loops install a similar handler.
		2477
		2478	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2479	AnyEvent will reset it to default, to avoid losing child exit statuses.
1804		2480
1805	=item SIGPIPE	2481	=item SIGPIPE
1806		2482
1807	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2483	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1808	when AnyEvent gets loaded.	2484	when AnyEvent gets loaded.
…		…
1820		2496
1821	=back	2497	=back
1822		2498
1823	=cut	2499	=cut
1824		2500
		2501	undef $SIG{CHLD}
		2502	if $SIG{CHLD} eq 'IGNORE';
		2503
1825	$SIG{PIPE} = sub { }	2504	$SIG{PIPE} = sub { }
1826	unless defined $SIG{PIPE};	2505	unless defined $SIG{PIPE};
1827		2506
		2507	=head1 RECOMMENDED/OPTIONAL MODULES
		2508
		2509	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2510	it's built-in modules) are required to use it.
		2511
		2512	That does not mean that AnyEvent won't take advantage of some additional
		2513	modules if they are installed.
		2514
		2515	This section explains which additional modules will be used, and how they
		2516	affect AnyEvent's operation.
		2517
		2518	=over 4
		2519
		2520	=item L<Async::Interrupt>
		2521
		2522	This slightly arcane module is used to implement fast signal handling: To
		2523	my knowledge, there is no way to do completely race-free and quick
		2524	signal handling in pure perl. To ensure that signals still get
		2525	delivered, AnyEvent will start an interval timer to wake up perl (and
		2526	catch the signals) with some delay (default is 10 seconds, look for
		2527	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2528
		2529	If this module is available, then it will be used to implement signal
		2530	catching, which means that signals will not be delayed, and the event loop
		2531	will not be interrupted regularly, which is more efficient (and good for
		2532	battery life on laptops).
		2533
		2534	This affects not just the pure-perl event loop, but also other event loops
		2535	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2536
		2537	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2538	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2539	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2540	does nothing for those backends.
		2541
		2542	=item L<EV>
		2543
		2544	This module isn't really "optional", as it is simply one of the backend
		2545	event loops that AnyEvent can use. However, it is simply the best event
		2546	loop available in terms of features, speed and stability: It supports
		2547	the AnyEvent API optimally, implements all the watcher types in XS, does
		2548	automatic timer adjustments even when no monotonic clock is available,
		2549	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2550	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2551	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2552
		2553	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2554	then this module will do nothing for you.
		2555
		2556	=item L<Guard>
		2557
		2558	The guard module, when used, will be used to implement
		2559	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2560	lot less memory), but otherwise doesn't affect guard operation much. It is
		2561	purely used for performance.
		2562
		2563	=item L<JSON> and L<JSON::XS>
		2564
		2565	One of these modules is required when you want to read or write JSON data
		2566	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2567	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2568
		2569	=item L<Net::SSLeay>
		2570
		2571	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2572	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2573	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2574
		2575	=item L<Time::HiRes>
		2576
		2577	This module is part of perl since release 5.008. It will be used when the
		2578	chosen event library does not come with a timing source on it's own. The
		2579	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2580	try to use a monotonic clock for timing stability.
		2581
		2582	=back
		2583
1828		2584
1829	=head1 FORK	2585	=head1 FORK
1830		2586
1831	Most event libraries are not fork-safe. The ones who are usually are	2587	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>	2588	because they rely on inefficient but fork-safe C<select> or C<poll> calls
1833	calls. Only L<EV> is fully fork-aware.	2589	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2590	are usually badly thought-out hacks that are incompatible with fork in
		2591	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2592	continue event-processing in both parent and child (or both, if you know
		2593	what you are doing).
		2594
		2595	This means that, in general, you cannot fork and do event processing in
		2596	the child if the event library was initialised before the fork (which
		2597	usually happens when the first AnyEvent watcher is created, or the library
		2598	is loaded).
1834		2599
1835	If you have to fork, you must either do so I<before> creating your first	2600	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.	2601	watcher OR you must not use AnyEvent at all in the child OR you must do
		2602	something completely out of the scope of AnyEvent.
		2603
		2604	The problem of doing event processing in the parent I<and> the child
		2605	is much more complicated: even for backends that I<are> fork-aware or
		2606	fork-safe, their behaviour is not usually what you want: fork clones all
		2607	watchers, that means all timers, I/O watchers etc. are active in both
		2608	parent and child, which is almost never what you want. USing C<exec>
		2609	to start worker children from some kind of manage rprocess is usually
		2610	preferred, because it is much easier and cleaner, at the expense of having
		2611	to have another binary.
1837		2612
1838		2613
1839	=head1 SECURITY CONSIDERATIONS	2614	=head1 SECURITY CONSIDERATIONS
1840		2615
1841	AnyEvent can be forced to load any event model via	2616	AnyEvent can be forced to load any event model via
…		…
1853	use AnyEvent;	2628	use AnyEvent;
1854		2629
1855	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2630	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	2631	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	2632	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1858	$ENV{PERL_ANYEGENT_STRICT}.	2633	$ENV{PERL_ANYEVENT_STRICT}.
		2634
		2635	Note that AnyEvent will remove I<all> environment variables starting with
		2636	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2637	enabled.
1859		2638
1860		2639
1861	=head1 BUGS	2640	=head1 BUGS
1862		2641
1863	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2642	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>.	2654	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1876		2655
1877	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2656	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1878	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2657	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1879	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2658	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1880	L<AnyEvent::Impl::POE>.	2659	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1881		2660
1882	Non-blocking file handles, sockets, TCP clients and	2661	Non-blocking file handles, sockets, TCP clients and
1883	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2662	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1884		2663
1885	Asynchronous DNS: L<AnyEvent::DNS>.	2664	Asynchronous DNS: L<AnyEvent::DNS>.
1886		2665
1887	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2666	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2667	L<Coro::Event>,
1888		2668
1889	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2669	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2670	L<AnyEvent::HTTP>.
1890		2671
1891		2672
1892	=head1 AUTHOR	2673	=head1 AUTHOR
1893		2674
1894	Marc Lehmann <schmorp@schmorp.de>	2675	Marc Lehmann <schmorp@schmorp.de>

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