[ViewVC] Diff of: cvs/AnyEvent/lib/AnyEvent.pm

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.170 by root, Wed Jul 9 11:53:40 2008 UTC vs.
Revision 1.228 by root, Wed Jul 8 01:11:12 2009 UTC

…		…
1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - provide framework for multiple event loops
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported
		6	event loops.
6		7
7	=head1 SYNOPSIS	8	=head1 SYNOPSIS
8		9
9	use AnyEvent;	10	use AnyEvent;
10		11
		12	# file descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub {	13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
		14
		15	# one-shot or repeating timers
		16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
		17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
		18
		19	print AnyEvent->now; # prints current event loop time
		20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
		21
		22	# POSIX signal
		23	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
		24
		25	# child process exit
		26	my $w = AnyEvent->child (pid => $pid, cb => sub {
		27	my ($pid, $status) = @_;
12	...	28	...
13	});	29	});
14		30
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	31	# called when event loop idle (if applicable)
16	...	32	my $w = AnyEvent->idle (cb => sub { ... });
17	});
18		33
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	34	my $w = AnyEvent->condvar; # stores whether a condition was flagged
20	$w->send; # wake up current and all future recv's	35	$w->send; # wake up current and all future recv's
21	$w->recv; # enters "main loop" till $condvar gets ->send	36	$w->recv; # enters "main loop" till $condvar gets ->send
		37	# use a condvar in callback mode:
		38	$w->cb (sub { $_[0]->recv });
22		39
23	=head1 INTRODUCTION/TUTORIAL	40	=head1 INTRODUCTION/TUTORIAL
24		41
25	This manpage is mainly a reference manual. If you are interested	42	This manpage is mainly a reference manual. If you are interested
26	in a tutorial or some gentle introduction, have a look at the	43	in a tutorial or some gentle introduction, have a look at the
128	These watchers are normal Perl objects with normal Perl lifetime. After	145	These watchers are normal Perl objects with normal Perl lifetime. After
129	creating a watcher it will immediately "watch" for events and invoke the	146	creating a watcher it will immediately "watch" for events and invoke the
130	callback when the event occurs (of course, only when the event model	147	callback when the event occurs (of course, only when the event model
131	is in control).	148	is in control).
132		149
		150	Note that B<callbacks must not permanently change global variables>
		151	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
		152	callbacks must not C<die> >>. The former is good programming practise in
		153	Perl and the latter stems from the fact that exception handling differs
		154	widely between event loops.
		155
133	To disable the watcher you have to destroy it (e.g. by setting the	156	To disable the watcher you have to destroy it (e.g. by setting the
134	variable you store it in to C<undef> or otherwise deleting all references	157	variable you store it in to C<undef> or otherwise deleting all references
135	to it).	158	to it).
136		159
137	All watchers are created by calling a method on the C<AnyEvent> class.	160	All watchers are created by calling a method on the C<AnyEvent> class.
…		…
153	=head2 I/O WATCHERS	176	=head2 I/O WATCHERS
154		177
155	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
156	with the following mandatory key-value pairs as arguments:	179	with the following mandatory key-value pairs as arguments:
157		180
158	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events	181	C<fh> is the Perl I<file handle> (I<not> file descriptor, see below) to
159	(AnyEvent might or might not keep a reference to this file handle). C<poll>	182	watch for events (AnyEvent might or might not keep a reference to this
		183	file handle). Note that only file handles pointing to things for which
		184	non-blocking operation makes sense are allowed. This includes sockets,
		185	most character devices, pipes, fifos and so on, but not for example files
		186	or block devices.
		187
160	must be a string that is either C<r> or C<w>, which creates a watcher	188	C<poll> must be a string that is either C<r> or C<w>, which creates a
161	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the	189	watcher waiting for "r"eadable or "w"ritable events, respectively.
		190
162	callback to invoke each time the file handle becomes ready.	191	C<cb> is the callback to invoke each time the file handle becomes ready.
163		192
164	Although the callback might get passed parameters, their value and	193	Although the callback might get passed parameters, their value and
165	presence is undefined and you cannot rely on them. Portable AnyEvent	194	presence is undefined and you cannot rely on them. Portable AnyEvent
166	callbacks cannot use arguments passed to I/O watcher callbacks.	195	callbacks cannot use arguments passed to I/O watcher callbacks.
167		196
…		…
180	chomp (my $input = <STDIN>);	209	chomp (my $input = <STDIN>);
181	warn "read: $input\n";	210	warn "read: $input\n";
182	undef $w;	211	undef $w;
183	});	212	});
184		213
		214	=head3 GETTING A FILE HANDLE FROM A FILE DESCRIPTOR
		215
		216	It is not uncommon to only have a file descriptor, while AnyEvent requires
		217	a Perl file handle.
		218
		219	There are basically two methods to convert a file descriptor into a file handle. If you own
		220	the file descriptor, you can open it with C<&=>, as in:
		221
		222	open my $fh, "<&=$fileno" or die "xxx: §!";
		223
		224	This will "own" the file descriptor, meaning that when C<$fh> is
		225	destroyed, it will automatically close the C<$fileno>. Also, note that
		226	the open mode (read, write, read/write) must correspond with how the
		227	underlying file descriptor was opened.
		228
		229	In many cases, taking over the file descriptor is now what you want, in
		230	which case the only alternative is to dup the file descriptor:
		231
		232	open my $fh, "<&$fileno" or die "xxx: $!";
		233
		234	This has the advantage of not closing the file descriptor and the
		235	disadvantage of making a slow copy.
		236
185	=head2 TIME WATCHERS	237	=head2 TIME WATCHERS
186		238
187	You can create a time watcher by calling the C<< AnyEvent->timer >>	239	You can create a time watcher by calling the C<< AnyEvent->timer >>
188	method with the following mandatory arguments:	240	method with the following mandatory arguments:
189		241
…		…
299	In either case, if you care (and in most cases, you don't), then you	351	In either case, if you care (and in most cases, you don't), then you
300	can get whatever behaviour you want with any event loop, by taking the	352	can get whatever behaviour you want with any event loop, by taking the
301	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	353	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
302	account.	354	account.
303		355
		356	=item AnyEvent->now_update
		357
		358	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		359	the current time for each loop iteration (see the discussion of L<<
		360	AnyEvent->now >>, above).
		361
		362	When a callback runs for a long time (or when the process sleeps), then
		363	this "current" time will differ substantially from the real time, which
		364	might affect timers and time-outs.
		365
		366	When this is the case, you can call this method, which will update the
		367	event loop's idea of "current time".
		368
		369	Note that updating the time I<might> cause some events to be handled.
		370
304	=back	371	=back
305		372
306	=head2 SIGNAL WATCHERS	373	=head2 SIGNAL WATCHERS
307		374
308	You can watch for signals using a signal watcher, C<signal> is the signal	375	You can watch for signals using a signal watcher, C<signal> is the signal
…		…
331	=head2 CHILD PROCESS WATCHERS	398	=head2 CHILD PROCESS WATCHERS
332		399
333	You can also watch on a child process exit and catch its exit status.	400	You can also watch on a child process exit and catch its exit status.
334		401
335	The child process is specified by the C<pid> argument (if set to C<0>, it	402	The child process is specified by the C<pid> argument (if set to C<0>, it
336	watches for any child process exit). The watcher will trigger as often	403	watches for any child process exit). The watcher will triggered only when
337	as status change for the child are received. This works by installing a	404	the child process has finished and an exit status is available, not on
338	signal handler for C<SIGCHLD>. The callback will be called with the pid	405	any trace events (stopped/continued).
339	and exit status (as returned by waitpid), so unlike other watcher types,	406
340	you I<can> rely on child watcher callback arguments.	407	The callback will be called with the pid and exit status (as returned by
		408	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		409	callback arguments.
		410
		411	This watcher type works by installing a signal handler for C<SIGCHLD>,
		412	and since it cannot be shared, nothing else should use SIGCHLD or reap
		413	random child processes (waiting for specific child processes, e.g. inside
		414	C<system>, is just fine).
341		415
342	There is a slight catch to child watchers, however: you usually start them	416	There is a slight catch to child watchers, however: you usually start them
343	I<after> the child process was created, and this means the process could	417	I<after> the child process was created, and this means the process could
344	have exited already (and no SIGCHLD will be sent anymore).	418	have exited already (and no SIGCHLD will be sent anymore).
345		419
346	Not all event models handle this correctly (POE doesn't), but even for	420	Not all event models handle this correctly (neither POE nor IO::Async do,
		421	see their AnyEvent::Impl manpages for details), but even for event models
347	event models that I<do> handle this correctly, they usually need to be	422	that I<do> handle this correctly, they usually need to be loaded before
348	loaded before the process exits (i.e. before you fork in the first place).	423	the process exits (i.e. before you fork in the first place). AnyEvent's
		424	pure perl event loop handles all cases correctly regardless of when you
		425	start the watcher.
349		426
350	This means you cannot create a child watcher as the very first thing in an	427	This means you cannot create a child watcher as the very first
351	AnyEvent program, you I<have> to create at least one watcher before you	428	thing in an AnyEvent program, you I<have> to create at least one
352	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	429	watcher before you C<fork> the child (alternatively, you can call
		430	C<AnyEvent::detect>).
353		431
354	Example: fork a process and wait for it	432	Example: fork a process and wait for it
355		433
356	my $done = AnyEvent->condvar;	434	my $done = AnyEvent->condvar;
357		435
…		…
367	);	445	);
368		446
369	# do something else, then wait for process exit	447	# do something else, then wait for process exit
370	$done->recv;	448	$done->recv;
371		449
		450	=head2 IDLE WATCHERS
		451
		452	Sometimes there is a need to do something, but it is not so important
		453	to do it instantly, but only when there is nothing better to do. This
		454	"nothing better to do" is usually defined to be "no other events need
		455	attention by the event loop".
		456
		457	Idle watchers ideally get invoked when the event loop has nothing
		458	better to do, just before it would block the process to wait for new
		459	events. Instead of blocking, the idle watcher is invoked.
		460
		461	Most event loops unfortunately do not really support idle watchers (only
		462	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		463	will simply call the callback "from time to time".
		464
		465	Example: read lines from STDIN, but only process them when the
		466	program is otherwise idle:
		467
		468	my @lines; # read data
		469	my $idle_w;
		470	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		471	push @lines, scalar <STDIN>;
		472
		473	# start an idle watcher, if not already done
		474	$idle_w \|\|= AnyEvent->idle (cb => sub {
		475	# handle only one line, when there are lines left
		476	if (my $line = shift @lines) {
		477	print "handled when idle: $line";
		478	} else {
		479	# otherwise disable the idle watcher again
		480	undef $idle_w;
		481	}
		482	});
		483	});
		484
372	=head2 CONDITION VARIABLES	485	=head2 CONDITION VARIABLES
373		486
374	If you are familiar with some event loops you will know that all of them	487	If you are familiar with some event loops you will know that all of them
375	require you to run some blocking "loop", "run" or similar function that	488	require you to run some blocking "loop", "run" or similar function that
376	will actively watch for new events and call your callbacks.	489	will actively watch for new events and call your callbacks.
…		…
381	The instrument to do that is called a "condition variable", so called	494	The instrument to do that is called a "condition variable", so called
382	because they represent a condition that must become true.	495	because they represent a condition that must become true.
383		496
384	Condition variables can be created by calling the C<< AnyEvent->condvar	497	Condition variables can be created by calling the C<< AnyEvent->condvar
385	>> method, usually without arguments. The only argument pair allowed is	498	>> method, usually without arguments. The only argument pair allowed is
		499
386	C<cb>, which specifies a callback to be called when the condition variable	500	C<cb>, which specifies a callback to be called when the condition variable
387	becomes true.	501	becomes true, with the condition variable as the first argument (but not
		502	the results).
388		503
389	After creation, the condition variable is "false" until it becomes "true"	504	After creation, the condition variable is "false" until it becomes "true"
390	by calling the C<send> method (or calling the condition variable as if it	505	by calling the C<send> method (or calling the condition variable as if it
391	were a callback, read about the caveats in the description for the C<<	506	were a callback, read about the caveats in the description for the C<<
392	->send >> method).	507	->send >> method).
…		…
448		563
449	my $done = AnyEvent->condvar;	564	my $done = AnyEvent->condvar;
450	my $delay = AnyEvent->timer (after => 5, cb => $done);	565	my $delay = AnyEvent->timer (after => 5, cb => $done);
451	$done->recv;	566	$done->recv;
452		567
		568	Example: Imagine an API that returns a condvar and doesn't support
		569	callbacks. This is how you make a synchronous call, for example from
		570	the main program:
		571
		572	use AnyEvent::CouchDB;
		573
		574	...
		575
		576	my @info = $couchdb->info->recv;
		577
		578	And this is how you would just ste a callback to be called whenever the
		579	results are available:
		580
		581	$couchdb->info->cb (sub {
		582	my @info = $_[0]->recv;
		583	});
		584
453	=head3 METHODS FOR PRODUCERS	585	=head3 METHODS FOR PRODUCERS
454		586
455	These methods should only be used by the producing side, i.e. the	587	These methods should only be used by the producing side, i.e. the
456	code/module that eventually sends the signal. Note that it is also	588	code/module that eventually sends the signal. Note that it is also
457	the producer side which creates the condvar in most cases, but it isn't	589	the producer side which creates the condvar in most cases, but it isn't
…		…
490		622
491	=item $cv->begin ([group callback])	623	=item $cv->begin ([group callback])
492		624
493	=item $cv->end	625	=item $cv->end
494		626
495	These two methods are EXPERIMENTAL and MIGHT CHANGE.
496
497	These two methods can be used to combine many transactions/events into	627	These two methods can be used to combine many transactions/events into
498	one. For example, a function that pings many hosts in parallel might want	628	one. For example, a function that pings many hosts in parallel might want
499	to use a condition variable for the whole process.	629	to use a condition variable for the whole process.
500		630
501	Every call to C<< ->begin >> will increment a counter, and every call to	631	Every call to C<< ->begin >> will increment a counter, and every call to
502	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	632	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
503	>>, the (last) callback passed to C<begin> will be executed. That callback	633	>>, the (last) callback passed to C<begin> will be executed. That callback
504	is I<supposed> to call C<< ->send >>, but that is not required. If no	634	is I<supposed> to call C<< ->send >>, but that is not required. If no
505	callback was set, C<send> will be called without any arguments.	635	callback was set, C<send> will be called without any arguments.
506		636
507	Let's clarify this with the ping example:	637	You can think of C<< $cv->send >> giving you an OR condition (one call
		638	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		639	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		640
		641	Let's start with a simple example: you have two I/O watchers (for example,
		642	STDOUT and STDERR for a program), and you want to wait for both streams to
		643	close before activating a condvar:
		644
		645	my $cv = AnyEvent->condvar;
		646
		647	$cv->begin; # first watcher
		648	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		649	defined sysread $fh1, my $buf, 4096
		650	or $cv->end;
		651	});
		652
		653	$cv->begin; # second watcher
		654	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		655	defined sysread $fh2, my $buf, 4096
		656	or $cv->end;
		657	});
		658
		659	$cv->recv;
		660
		661	This works because for every event source (EOF on file handle), there is
		662	one call to C<begin>, so the condvar waits for all calls to C<end> before
		663	sending.
		664
		665	The ping example mentioned above is slightly more complicated, as the
		666	there are results to be passwd back, and the number of tasks that are
		667	begung can potentially be zero:
508		668
509	my $cv = AnyEvent->condvar;	669	my $cv = AnyEvent->condvar;
510		670
511	my %result;	671	my %result;
512	$cv->begin (sub { $cv->send (\%result) });	672	$cv->begin (sub { $cv->send (\%result) });
…		…
532	loop, which serves two important purposes: first, it sets the callback	692	loop, which serves two important purposes: first, it sets the callback
533	to be called once the counter reaches C<0>, and second, it ensures that	693	to be called once the counter reaches C<0>, and second, it ensures that
534	C<send> is called even when C<no> hosts are being pinged (the loop	694	C<send> is called even when C<no> hosts are being pinged (the loop
535	doesn't execute once).	695	doesn't execute once).
536		696
537	This is the general pattern when you "fan out" into multiple subrequests:	697	This is the general pattern when you "fan out" into multiple (but
538	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	698	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
539	is called at least once, and then, for each subrequest you start, call	699	the callback and ensure C<end> is called at least once, and then, for each
540	C<begin> and for each subrequest you finish, call C<end>.	700	subrequest you start, call C<begin> and for each subrequest you finish,
		701	call C<end>.
541		702
542	=back	703	=back
543		704
544	=head3 METHODS FOR CONSUMERS	705	=head3 METHODS FOR CONSUMERS
545		706
…		…
590	=item $bool = $cv->ready	751	=item $bool = $cv->ready
591		752
592	Returns true when the condition is "true", i.e. whether C<send> or	753	Returns true when the condition is "true", i.e. whether C<send> or
593	C<croak> have been called.	754	C<croak> have been called.
594		755
595	=item $cb = $cv->cb ([new callback])	756	=item $cb = $cv->cb ($cb->($cv))
596		757
597	This is a mutator function that returns the callback set and optionally	758	This is a mutator function that returns the callback set and optionally
598	replaces it before doing so.	759	replaces it before doing so.
599		760
600	The callback will be called when the condition becomes "true", i.e. when	761	The callback will be called when the condition becomes "true", i.e. when
…		…
625	AnyEvent::Impl::Tk based on Tk, very bad choice.	786	AnyEvent::Impl::Tk based on Tk, very bad choice.
626	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).	787	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
627	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	788	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
628	AnyEvent::Impl::POE based on POE, not generic enough for full support.	789	AnyEvent::Impl::POE based on POE, not generic enough for full support.
629		790
		791	# warning, support for IO::Async is only partial, as it is too broken
		792	# and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
		793	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
		794
630	There is no support for WxWidgets, as WxWidgets has no support for	795	There is no support for WxWidgets, as WxWidgets has no support for
631	watching file handles. However, you can use WxWidgets through the	796	watching file handles. However, you can use WxWidgets through the
632	POE Adaptor, as POE has a Wx backend that simply polls 20 times per	797	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
633	second, which was considered to be too horrible to even consider for	798	second, which was considered to be too horrible to even consider for
634	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using	799	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
…		…
790	=item L<AnyEvent::IGS>	955	=item L<AnyEvent::IGS>
791		956
792	A non-blocking interface to the Internet Go Server protocol (used by	957	A non-blocking interface to the Internet Go Server protocol (used by
793	L<App::IGS>).	958	L<App::IGS>).
794		959
795	=item L<Net::IRC3>	960	=item L<AnyEvent::IRC>
796		961
797	AnyEvent based IRC client module family.	962	AnyEvent based IRC client module family (replacing the older Net::IRC3).
798		963
799	=item L<Net::XMPP2>	964	=item L<Net::XMPP2>
800		965
801	AnyEvent based XMPP (Jabber protocol) module family.	966	AnyEvent based XMPP (Jabber protocol) module family.
802		967
…		…
822	=cut	987	=cut
823		988
824	package AnyEvent;	989	package AnyEvent;
825		990
826	no warnings;	991	no warnings;
827	use strict;	992	use strict qw(vars subs);
828		993
829	use Carp;	994	use Carp;
830		995
831	our $VERSION = 4.2;	996	our $VERSION = 4.8;
832	our $MODEL;	997	our $MODEL;
833		998
834	our $AUTOLOAD;	999	our $AUTOLOAD;
835	our @ISA;	1000	our @ISA;
836		1001
837	our @REGISTRY;	1002	our @REGISTRY;
838		1003
839	our $WIN32;	1004	our $WIN32;
840		1005
841	BEGIN {	1006	BEGIN {
842	my $win32 = ! ! ($^O =~ /mswin32/i);	1007	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
843	eval "sub WIN32(){ $win32 }";	1008	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
		1009
		1010	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1011	if ${^TAINT};
844	}	1012	}
845		1013
846	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1014	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
847		1015
848	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred	1016	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
…		…
866	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1034	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
867	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1035	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
868	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1036	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
869	[Wx:: => AnyEvent::Impl::POE::],	1037	[Wx:: => AnyEvent::Impl::POE::],
870	[Prima:: => AnyEvent::Impl::POE::],	1038	[Prima:: => AnyEvent::Impl::POE::],
		1039	# IO::Async is just too broken - we would need workaorunds for its
		1040	# byzantine signal and broken child handling, among others.
		1041	# IO::Async is rather hard to detect, as it doesn't have any
		1042	# obvious default class.
		1043	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1044	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1045	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
871	);	1046	);
872		1047
873	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1048	our %method = map +($_ => 1),
		1049	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
874		1050
875	our @post_detect;	1051	our @post_detect;
876		1052
877	sub post_detect(&) {	1053	sub post_detect(&) {
878	my ($cb) = @_;	1054	my ($cb) = @_;
…		…
883	1	1059	1
884	} else {	1060	} else {
885	push @post_detect, $cb;	1061	push @post_detect, $cb;
886		1062
887	defined wantarray	1063	defined wantarray
888	? bless \$cb, "AnyEvent::Util::PostDetect"	1064	? bless \$cb, "AnyEvent::Util::postdetect"
889	: ()	1065	: ()
890	}	1066	}
891	}	1067	}
892		1068
893	sub AnyEvent::Util::PostDetect::DESTROY {	1069	sub AnyEvent::Util::postdetect::DESTROY {
894	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1070	@post_detect = grep $_ != ${$_[0]}, @post_detect;
895	}	1071	}
896		1072
897	sub detect() {	1073	sub detect() {
898	unless ($MODEL) {	1074	unless ($MODEL) {
…		…
935	last;	1111	last;
936	}	1112	}
937	}	1113	}
938		1114
939	$MODEL	1115	$MODEL
940	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1116	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
941	}	1117	}
942	}	1118	}
943		1119
944	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1120	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
945		1121
…		…
966	}	1142	}
967		1143
968	# utility function to dup a filehandle. this is used by many backends	1144	# utility function to dup a filehandle. this is used by many backends
969	# to support binding more than one watcher per filehandle (they usually	1145	# to support binding more than one watcher per filehandle (they usually
970	# allow only one watcher per fd, so we dup it to get a different one).	1146	# allow only one watcher per fd, so we dup it to get a different one).
971	sub _dupfh($$$$) {	1147	sub _dupfh($$;$$) {
972	my ($poll, $fh, $r, $w) = @_;	1148	my ($poll, $fh, $r, $w) = @_;
973
974	require Fcntl;
975		1149
976	# cygwin requires the fh mode to be matching, unix doesn't	1150	# cygwin requires the fh mode to be matching, unix doesn't
977	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1151	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
978	: $poll eq "w" ? ($w, ">")	1152	: $poll eq "w" ? ($w, ">")
979	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";	1153	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
980		1154
981	open my $fh2, "$mode&" . fileno $fh	1155	open my $fh2, "$mode&" . fileno $fh
982	or die "cannot dup() filehandle: $!";	1156	or die "cannot dup() filehandle: $!,";
983		1157
984	# we assume CLOEXEC is already set by perl in all important cases	1158	# we assume CLOEXEC is already set by perl in all important cases
985		1159
986	($fh2, $rw)	1160	($fh2, $rw)
987	}	1161	}
988		1162
989	package AnyEvent::Base;	1163	package AnyEvent::Base;
990		1164
991	# default implementation for now and time	1165	# default implementations for many methods
992		1166
993	use Time::HiRes ();	1167	BEGIN {
		1168	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1169	*_time = \&Time::HiRes::time;
		1170	# if (eval "use POSIX (); (POSIX::times())...
		1171	} else {
		1172	*_time = sub { time }; # epic fail
		1173	}
		1174	}
994		1175
995	sub time { Time::HiRes::time }	1176	sub time { _time }
996	sub now { Time::HiRes::time }	1177	sub now { _time }
		1178	sub now_update { }
997		1179
998	# default implementation for ->condvar	1180	# default implementation for ->condvar
999		1181
1000	sub condvar {	1182	sub condvar {
1001	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1183	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1002	}	1184	}
1003		1185
1004	# default implementation for ->signal	1186	# default implementation for ->signal
1005		1187
1006	our %SIG_CB;	1188	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1189
		1190	sub _signal_exec {
		1191	sysread $SIGPIPE_R, my $dummy, 4;
		1192
		1193	while (%SIG_EV) {
		1194	for (keys %SIG_EV) {
		1195	delete $SIG_EV{$_};
		1196	$_->() for values %{ $SIG_CB{$_} \|\| {} };
		1197	}
		1198	}
		1199	}
1007		1200
1008	sub signal {	1201	sub signal {
1009	my (undef, %arg) = @_;	1202	my (undef, %arg) = @_;
1010		1203
		1204	unless ($SIGPIPE_R) {
		1205	require Fcntl;
		1206
		1207	if (AnyEvent::WIN32) {
		1208	require AnyEvent::Util;
		1209
		1210	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1211	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1212	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1213	} else {
		1214	pipe $SIGPIPE_R, $SIGPIPE_W;
		1215	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1216	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1217
		1218	# not strictly required, as $^F is normally 2, but let's make sure...
		1219	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1220	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1221	}
		1222
		1223	$SIGPIPE_R
		1224	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1225
		1226	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1227	}
		1228
1011	my $signal = uc $arg{signal}	1229	my $signal = uc $arg{signal}
1012	or Carp::croak "required option 'signal' is missing";	1230	or Carp::croak "required option 'signal' is missing";
1013		1231
1014	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1232	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1015	$SIG{$signal} \|\|= sub {	1233	$SIG{$signal} \|\|= sub {
1016	$_->() for values %{ $SIG_CB{$signal} \|\| {} };	1234	local $!;
		1235	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1236	undef $SIG_EV{$signal};
1017	};	1237	};
1018		1238
1019	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1239	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1020	}	1240	}
1021		1241
1022	sub AnyEvent::Base::Signal::DESTROY {	1242	sub AnyEvent::Base::signal::DESTROY {
1023	my ($signal, $cb) = @{$_[0]};	1243	my ($signal, $cb) = @{$_[0]};
1024		1244
1025	delete $SIG_CB{$signal}{$cb};	1245	delete $SIG_CB{$signal}{$cb};
1026		1246
		1247	# delete doesn't work with older perls - they then
		1248	# print weird messages, or just unconditionally exit
		1249	# instead of getting the default action.
1027	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };	1250	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1028	}	1251	}
1029		1252
1030	# default implementation for ->child	1253	# default implementation for ->child
1031		1254
1032	our %PID_CB;	1255	our %PID_CB;
1033	our $CHLD_W;	1256	our $CHLD_W;
1034	our $CHLD_DELAY_W;	1257	our $CHLD_DELAY_W;
1035	our $PID_IDLE;
1036	our $WNOHANG;	1258	our $WNOHANG;
1037		1259
1038	sub _child_wait {	1260	sub _sigchld {
1039	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1261	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1040	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),	1262	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),
1041	(values %{ $PID_CB{0} \|\| {} });	1263	(values %{ $PID_CB{0} \|\| {} });
1042	}	1264	}
1043
1044	undef $PID_IDLE;
1045	}
1046
1047	sub _sigchld {
1048	# make sure we deliver these changes "synchronous" with the event loop.
1049	$CHLD_DELAY_W \|\|= AnyEvent->timer (after => 0, cb => sub {
1050	undef $CHLD_DELAY_W;
1051	&_child_wait;
1052	});
1053	}	1265	}
1054		1266
1055	sub child {	1267	sub child {
1056	my (undef, %arg) = @_;	1268	my (undef, %arg) = @_;
1057		1269
1058	defined (my $pid = $arg{pid} + 0)	1270	defined (my $pid = $arg{pid} + 0)
1059	or Carp::croak "required option 'pid' is missing";	1271	or Carp::croak "required option 'pid' is missing";
1060		1272
1061	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1273	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1062		1274
1063	unless ($WNOHANG) {
1064	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;	1275	$WNOHANG \|\|= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
1065	}
1066		1276
1067	unless ($CHLD_W) {	1277	unless ($CHLD_W) {
1068	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1278	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1069	# child could be a zombie already, so make at least one round	1279	# child could be a zombie already, so make at least one round
1070	&_sigchld;	1280	&_sigchld;
1071	}	1281	}
1072		1282
1073	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1283	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1074	}	1284	}
1075		1285
1076	sub AnyEvent::Base::Child::DESTROY {	1286	sub AnyEvent::Base::child::DESTROY {
1077	my ($pid, $cb) = @{$_[0]};	1287	my ($pid, $cb) = @{$_[0]};
1078		1288
1079	delete $PID_CB{$pid}{$cb};	1289	delete $PID_CB{$pid}{$cb};
1080	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1290	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1081		1291
1082	undef $CHLD_W unless keys %PID_CB;	1292	undef $CHLD_W unless keys %PID_CB;
		1293	}
		1294
		1295	# idle emulation is done by simply using a timer, regardless
		1296	# of whether the process is idle or not, and not letting
		1297	# the callback use more than 50% of the time.
		1298	sub idle {
		1299	my (undef, %arg) = @_;
		1300
		1301	my ($cb, $w, $rcb) = $arg{cb};
		1302
		1303	$rcb = sub {
		1304	if ($cb) {
		1305	$w = _time;
		1306	&$cb;
		1307	$w = _time - $w;
		1308
		1309	# never use more then 50% of the time for the idle watcher,
		1310	# within some limits
		1311	$w = 0.0001 if $w < 0.0001;
		1312	$w = 5 if $w > 5;
		1313
		1314	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1315	} else {
		1316	# clean up...
		1317	undef $w;
		1318	undef $rcb;
		1319	}
		1320	};
		1321
		1322	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1323
		1324	bless \\$cb, "AnyEvent::Base::idle"
		1325	}
		1326
		1327	sub AnyEvent::Base::idle::DESTROY {
		1328	undef $${$_[0]};
1083	}	1329	}
1084		1330
1085	package AnyEvent::CondVar;	1331	package AnyEvent::CondVar;
1086		1332
1087	our @ISA = AnyEvent::CondVar::Base::;	1333	our @ISA = AnyEvent::CondVar::Base::;
…		…
1139	}	1385	}
1140		1386
1141	# undocumented/compatibility with pre-3.4	1387	# undocumented/compatibility with pre-3.4
1142	*broadcast = \&send;	1388	*broadcast = \&send;
1143	*wait = \&_wait;	1389	*wait = \&_wait;
		1390
		1391	=head1 ERROR AND EXCEPTION HANDLING
		1392
		1393	In general, AnyEvent does not do any error handling - it relies on the
		1394	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1395	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1396	checking of all AnyEvent methods, however, which is highly useful during
		1397	development.
		1398
		1399	As for exception handling (i.e. runtime errors and exceptions thrown while
		1400	executing a callback), this is not only highly event-loop specific, but
		1401	also not in any way wrapped by this module, as this is the job of the main
		1402	program.
		1403
		1404	The pure perl event loop simply re-throws the exception (usually
		1405	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1406	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1407	so on.
		1408
		1409	=head1 ENVIRONMENT VARIABLES
		1410
		1411	The following environment variables are used by this module or its
		1412	submodules.
		1413
		1414	Note that AnyEvent will remove I<all> environment variables starting with
		1415	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1416	enabled.
		1417
		1418	=over 4
		1419
		1420	=item C<PERL_ANYEVENT_VERBOSE>
		1421
		1422	By default, AnyEvent will be completely silent except in fatal
		1423	conditions. You can set this environment variable to make AnyEvent more
		1424	talkative.
		1425
		1426	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1427	conditions, such as not being able to load the event model specified by
		1428	C<PERL_ANYEVENT_MODEL>.
		1429
		1430	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1431	model it chooses.
		1432
		1433	=item C<PERL_ANYEVENT_STRICT>
		1434
		1435	AnyEvent does not do much argument checking by default, as thorough
		1436	argument checking is very costly. Setting this variable to a true value
		1437	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1438	check the arguments passed to most method calls. If it finds any problems,
		1439	it will croak.
		1440
		1441	In other words, enables "strict" mode.
		1442
		1443	Unlike C<use strict>, it is definitely recommended to keep it off in
		1444	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1445	developing programs can be very useful, however.
		1446
		1447	=item C<PERL_ANYEVENT_MODEL>
		1448
		1449	This can be used to specify the event model to be used by AnyEvent, before
		1450	auto detection and -probing kicks in. It must be a string consisting
		1451	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1452	and the resulting module name is loaded and if the load was successful,
		1453	used as event model. If it fails to load AnyEvent will proceed with
		1454	auto detection and -probing.
		1455
		1456	This functionality might change in future versions.
		1457
		1458	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1459	could start your program like this:
		1460
		1461	PERL_ANYEVENT_MODEL=Perl perl ...
		1462
		1463	=item C<PERL_ANYEVENT_PROTOCOLS>
		1464
		1465	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1466	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1467	of auto probing).
		1468
		1469	Must be set to a comma-separated list of protocols or address families,
		1470	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1471	used, and preference will be given to protocols mentioned earlier in the
		1472	list.
		1473
		1474	This variable can effectively be used for denial-of-service attacks
		1475	against local programs (e.g. when setuid), although the impact is likely
		1476	small, as the program has to handle conenction and other failures anyways.
		1477
		1478	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1479	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1480	- only support IPv4, never try to resolve or contact IPv6
		1481	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1482	IPv6, but prefer IPv6 over IPv4.
		1483
		1484	=item C<PERL_ANYEVENT_EDNS0>
		1485
		1486	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1487	for DNS. This extension is generally useful to reduce DNS traffic, but
		1488	some (broken) firewalls drop such DNS packets, which is why it is off by
		1489	default.
		1490
		1491	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1492	EDNS0 in its DNS requests.
		1493
		1494	=item C<PERL_ANYEVENT_MAX_FORKS>
		1495
		1496	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1497	will create in parallel.
		1498
		1499	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1500
		1501	The default value for the C<max_outstanding> parameter for the default DNS
		1502	resolver - this is the maximum number of parallel DNS requests that are
		1503	sent to the DNS server.
		1504
		1505	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1506
		1507	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1508	configuration) in the default resolver. When set to the empty string, no
		1509	default config will be used.
		1510
		1511	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1512
		1513	When neither C<ca_file> nor C<ca_path> was specified during
		1514	L<AnyEvent::TLS> context creation, and either of these environment
		1515	variables exist, they will be used to specify CA certificate locations
		1516	instead of a system-dependent default.
		1517
		1518	=back
1144		1519
1145	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1520	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1146		1521
1147	This is an advanced topic that you do not normally need to use AnyEvent in	1522	This is an advanced topic that you do not normally need to use AnyEvent in
1148	a module. This section is only of use to event loop authors who want to	1523	a module. This section is only of use to event loop authors who want to
…		…
1182		1557
1183	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1558	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1184	condition variables: code blocking while waiting for a condition will	1559	condition variables: code blocking while waiting for a condition will
1185	C<die>. This still works with most modules/usages, and blocking calls must	1560	C<die>. This still works with most modules/usages, and blocking calls must
1186	not be done in an interactive application, so it makes sense.	1561	not be done in an interactive application, so it makes sense.
1187
1188	=head1 ENVIRONMENT VARIABLES
1189
1190	The following environment variables are used by this module:
1191
1192	=over 4
1193
1194	=item C<PERL_ANYEVENT_VERBOSE>
1195
1196	By default, AnyEvent will be completely silent except in fatal
1197	conditions. You can set this environment variable to make AnyEvent more
1198	talkative.
1199
1200	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1201	conditions, such as not being able to load the event model specified by
1202	C<PERL_ANYEVENT_MODEL>.
1203
1204	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1205	model it chooses.
1206
1207	=item C<PERL_ANYEVENT_STRICT>
1208
1209	AnyEvent does not do much argument checking by default, as thorough
1210	argument checking is very costly. Setting this variable to a true value
1211	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1212	check the arguments passed to most method calls. If it finds any problems
1213	it will croak.
1214
1215	In other words, enables "strict" mode.
1216
1217	Unlike C<use strict> it is definitely recommended ot keep it off in
1218	production.
1219
1220	=item C<PERL_ANYEVENT_MODEL>
1221
1222	This can be used to specify the event model to be used by AnyEvent, before
1223	auto detection and -probing kicks in. It must be a string consisting
1224	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1225	and the resulting module name is loaded and if the load was successful,
1226	used as event model. If it fails to load AnyEvent will proceed with
1227	auto detection and -probing.
1228
1229	This functionality might change in future versions.
1230
1231	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1232	could start your program like this:
1233
1234	PERL_ANYEVENT_MODEL=Perl perl ...
1235
1236	=item C<PERL_ANYEVENT_PROTOCOLS>
1237
1238	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1239	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1240	of auto probing).
1241
1242	Must be set to a comma-separated list of protocols or address families,
1243	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1244	used, and preference will be given to protocols mentioned earlier in the
1245	list.
1246
1247	This variable can effectively be used for denial-of-service attacks
1248	against local programs (e.g. when setuid), although the impact is likely
1249	small, as the program has to handle connection errors already-
1250
1251	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1252	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1253	- only support IPv4, never try to resolve or contact IPv6
1254	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1255	IPv6, but prefer IPv6 over IPv4.
1256
1257	=item C<PERL_ANYEVENT_EDNS0>
1258
1259	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1260	for DNS. This extension is generally useful to reduce DNS traffic, but
1261	some (broken) firewalls drop such DNS packets, which is why it is off by
1262	default.
1263
1264	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1265	EDNS0 in its DNS requests.
1266
1267	=item C<PERL_ANYEVENT_MAX_FORKS>
1268
1269	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1270	will create in parallel.
1271
1272	=back
1273		1562
1274	=head1 EXAMPLE PROGRAM	1563	=head1 EXAMPLE PROGRAM
1275		1564
1276	The following program uses an I/O watcher to read data from STDIN, a timer	1565	The following program uses an I/O watcher to read data from STDIN, a timer
1277	to display a message once per second, and a condition variable to quit the	1566	to display a message once per second, and a condition variable to quit the
…		…
1471	watcher.	1760	watcher.
1472		1761
1473	=head3 Results	1762	=head3 Results
1474		1763
1475	name watchers bytes create invoke destroy comment	1764	name watchers bytes create invoke destroy comment
1476	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1765	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1477	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1766	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1478	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1767	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1479	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1768	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1480	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1769	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1481	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	1770	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		1771	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		1772	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1482	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1773	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1483	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1774	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1484	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1775	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1485	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1776	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1486		1777
1487	=head3 Discussion	1778	=head3 Discussion
1488		1779
1489	The benchmark does I<not> measure scalability of the event loop very	1780	The benchmark does I<not> measure scalability of the event loop very
1490	well. For example, a select-based event loop (such as the pure perl one)	1781	well. For example, a select-based event loop (such as the pure perl one)
…		…
1515	performance becomes really bad with lots of file descriptors (and few of	1806	performance becomes really bad with lots of file descriptors (and few of
1516	them active), of course, but this was not subject of this benchmark.	1807	them active), of course, but this was not subject of this benchmark.
1517		1808
1518	The C<Event> module has a relatively high setup and callback invocation	1809	The C<Event> module has a relatively high setup and callback invocation
1519	cost, but overall scores in on the third place.	1810	cost, but overall scores in on the third place.
		1811
		1812	C<IO::Async> performs admirably well, about on par with C<Event>, even
		1813	when using its pure perl backend.
1520		1814
1521	C<Glib>'s memory usage is quite a bit higher, but it features a	1815	C<Glib>'s memory usage is quite a bit higher, but it features a
1522	faster callback invocation and overall ends up in the same class as	1816	faster callback invocation and overall ends up in the same class as
1523	C<Event>. However, Glib scales extremely badly, doubling the number of	1817	C<Event>. However, Glib scales extremely badly, doubling the number of
1524	watchers increases the processing time by more than a factor of four,	1818	watchers increases the processing time by more than a factor of four,
…		…
1602	it to another server. This includes deleting the old timeout and creating	1896	it to another server. This includes deleting the old timeout and creating
1603	a new one that moves the timeout into the future.	1897	a new one that moves the timeout into the future.
1604		1898
1605	=head3 Results	1899	=head3 Results
1606		1900
1607	name sockets create request	1901	name sockets create request
1608	EV 20000 69.01 11.16	1902	EV 20000 69.01 11.16
1609	Perl 20000 73.32 35.87	1903	Perl 20000 73.32 35.87
		1904	IOAsync 20000 157.00 98.14 epoll
		1905	IOAsync 20000 159.31 616.06 poll
1610	Event 20000 212.62 257.32	1906	Event 20000 212.62 257.32
1611	Glib 20000 651.16 1896.30	1907	Glib 20000 651.16 1896.30
1612	POE 20000 349.67 12317.24 uses POE::Loop::Event	1908	POE 20000 349.67 12317.24 uses POE::Loop::Event
1613		1909
1614	=head3 Discussion	1910	=head3 Discussion
1615		1911
1616	This benchmark I<does> measure scalability and overall performance of the	1912	This benchmark I<does> measure scalability and overall performance of the
1617	particular event loop.	1913	particular event loop.
…		…
1619	EV is again fastest. Since it is using epoll on my system, the setup time	1915	EV is again fastest. Since it is using epoll on my system, the setup time
1620	is relatively high, though.	1916	is relatively high, though.
1621		1917
1622	Perl surprisingly comes second. It is much faster than the C-based event	1918	Perl surprisingly comes second. It is much faster than the C-based event
1623	loops Event and Glib.	1919	loops Event and Glib.
		1920
		1921	IO::Async performs very well when using its epoll backend, and still quite
		1922	good compared to Glib when using its pure perl backend.
1624		1923
1625	Event suffers from high setup time as well (look at its code and you will	1924	Event suffers from high setup time as well (look at its code and you will
1626	understand why). Callback invocation also has a high overhead compared to	1925	understand why). Callback invocation also has a high overhead compared to
1627	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	1926	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1628	uses select or poll in basically all documented configurations.	1927	uses select or poll in basically all documented configurations.
…		…
1691	=item * C-based event loops perform very well with small number of	1990	=item * C-based event loops perform very well with small number of
1692	watchers, as the management overhead dominates.	1991	watchers, as the management overhead dominates.
1693		1992
1694	=back	1993	=back
1695		1994
		1995	=head2 THE IO::Lambda BENCHMARK
		1996
		1997	Recently I was told about the benchmark in the IO::Lambda manpage, which
		1998	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		1999	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2000	shouldn't come as a surprise to anybody). As such, the benchmark is
		2001	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2002	very optimal. But how would AnyEvent compare when used without the extra
		2003	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2004
		2005	The benchmark itself creates an echo-server, and then, for 500 times,
		2006	connects to the echo server, sends a line, waits for the reply, and then
		2007	creates the next connection. This is a rather bad benchmark, as it doesn't
		2008	test the efficiency of the framework or much non-blocking I/O, but it is a
		2009	benchmark nevertheless.
		2010
		2011	name runtime
		2012	Lambda/select 0.330 sec
		2013	+ optimized 0.122 sec
		2014	Lambda/AnyEvent 0.327 sec
		2015	+ optimized 0.138 sec
		2016	Raw sockets/select 0.077 sec
		2017	POE/select, components 0.662 sec
		2018	POE/select, raw sockets 0.226 sec
		2019	POE/select, optimized 0.404 sec
		2020
		2021	AnyEvent/select/nb 0.085 sec
		2022	AnyEvent/EV/nb 0.068 sec
		2023	+state machine 0.134 sec
		2024
		2025	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2026	benchmarks actually make blocking connects and use 100% blocking I/O,
		2027	defeating the purpose of an event-based solution. All of the newly
		2028	written AnyEvent benchmarks use 100% non-blocking connects (using
		2029	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2030	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2031	generally require a lot more bookkeeping and event handling than blocking
		2032	connects (which involve a single syscall only).
		2033
		2034	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2035	offers similar expressive power as POE and IO::Lambda, using conventional
		2036	Perl syntax. This means that both the echo server and the client are 100%
		2037	non-blocking, further placing it at a disadvantage.
		2038
		2039	As you can see, the AnyEvent + EV combination even beats the
		2040	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2041	backend easily beats IO::Lambda and POE.
		2042
		2043	And even the 100% non-blocking version written using the high-level (and
		2044	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2045	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2046	in a non-blocking way.
		2047
		2048	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2049	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2050	part of the IO::lambda distribution and were used without any changes.
		2051
		2052
		2053	=head1 SIGNALS
		2054
		2055	AnyEvent currently installs handlers for these signals:
		2056
		2057	=over 4
		2058
		2059	=item SIGCHLD
		2060
		2061	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		2062	emulation for event loops that do not support them natively. Also, some
		2063	event loops install a similar handler.
		2064
		2065	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will
		2066	reset it to default, to avoid losing child exit statuses.
		2067
		2068	=item SIGPIPE
		2069
		2070	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		2071	when AnyEvent gets loaded.
		2072
		2073	The rationale for this is that AnyEvent users usually do not really depend
		2074	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		2075	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		2076	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		2077	some random socket.
		2078
		2079	The rationale for installing a no-op handler as opposed to ignoring it is
		2080	that this way, the handler will be restored to defaults on exec.
		2081
		2082	Feel free to install your own handler, or reset it to defaults.
		2083
		2084	=back
		2085
		2086	=cut
		2087
		2088	undef $SIG{CHLD}
		2089	if $SIG{CHLD} eq 'IGNORE';
		2090
		2091	$SIG{PIPE} = sub { }
		2092	unless defined $SIG{PIPE};
1696		2093
1697	=head1 FORK	2094	=head1 FORK
1698		2095
1699	Most event libraries are not fork-safe. The ones who are usually are	2096	Most event libraries are not fork-safe. The ones who are usually are
1700	because they rely on inefficient but fork-safe C<select> or C<poll>	2097	because they rely on inefficient but fork-safe C<select> or C<poll>
…		…
1721	use AnyEvent;	2118	use AnyEvent;
1722		2119
1723	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2120	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1724	be used to probe what backend is used and gain other information (which is	2121	be used to probe what backend is used and gain other information (which is
1725	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2122	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1726	$ENV{PERL_ANYEGENT_STRICT}.	2123	$ENV{PERL_ANYEVENT_STRICT}.
		2124
		2125	Note that AnyEvent will remove I<all> environment variables starting with
		2126	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2127	enabled.
1727		2128
1728		2129
1729	=head1 BUGS	2130	=head1 BUGS
1730		2131
1731	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2132	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1732	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2133	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1733	and check wether the leaks still show up. (Perl 5.10.0 has other annoying	2134	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1734	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as	2135	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1735	pronounced).	2136	pronounced).
1736		2137
1737		2138
1738	=head1 SEE ALSO	2139	=head1 SEE ALSO
1739		2140

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.170 by root, Wed Jul 9 11:53:40 2008 UTC vs. Revision 1.228 by root, Wed Jul 8 01:11:12 2009 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.170 by root, Wed Jul 9 11:53:40 2008 UTC vs.
Revision 1.228 by root, Wed Jul 8 01:11:12 2009 UTC