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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.164 by root, Tue Jul 8 19:50:25 2008 UTC vs.
Revision 1.219 by root, Thu Jun 25 11:16:08 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
33		50
34	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of	51	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
35	policy> and AnyEvent is I<small and efficient>.	52	policy> and AnyEvent is I<small and efficient>.
36		53
37	First and foremost, I<AnyEvent is not an event model> itself, it only	54	First and foremost, I<AnyEvent is not an event model> itself, it only
38	interfaces to whatever event model the main program happens to use in a	55	interfaces to whatever event model the main program happens to use, in a
39	pragmatic way. For event models and certain classes of immortals alike,	56	pragmatic way. For event models and certain classes of immortals alike,
40	the statement "there can only be one" is a bitter reality: In general,	57	the statement "there can only be one" is a bitter reality: In general,
41	only one event loop can be active at the same time in a process. AnyEvent	58	only one event loop can be active at the same time in a process. AnyEvent
42	helps hiding the differences between those event loops.	59	cannot change this, but it can hide the differences between those event
		60	loops.
43		61
44	The goal of AnyEvent is to offer module authors the ability to do event	62	The goal of AnyEvent is to offer module authors the ability to do event
45	programming (waiting for I/O or timer events) without subscribing to a	63	programming (waiting for I/O or timer events) without subscribing to a
46	religion, a way of living, and most importantly: without forcing your	64	religion, a way of living, and most importantly: without forcing your
47	module users into the same thing by forcing them to use the same event	65	module users into the same thing by forcing them to use the same event
48	model you use.	66	model you use.
49		67
50	For modules like POE or IO::Async (which is a total misnomer as it is	68	For modules like POE or IO::Async (which is a total misnomer as it is
51	actually doing all I/O I<synchronously>...), using them in your module is	69	actually doing all I/O I<synchronously>...), using them in your module is
52	like joining a cult: After you joined, you are dependent on them and you	70	like joining a cult: After you joined, you are dependent on them and you
53	cannot use anything else, as it is simply incompatible to everything that	71	cannot use anything else, as they are simply incompatible to everything
54	isn't itself. What's worse, all the potential users of your module are	72	that isn't them. What's worse, all the potential users of your
55	I<also> forced to use the same event loop you use.	73	module are I<also> forced to use the same event loop you use.
56		74
57	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	75	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
58	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	76	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
59	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if	77	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
60	your module uses one of those, every user of your module has to use it,	78	your module uses one of those, every user of your module has to use it,
61	too. But if your module uses AnyEvent, it works transparently with all	79	too. But if your module uses AnyEvent, it works transparently with all
62	event models it supports (including stuff like POE and IO::Async, as long	80	event models it supports (including stuff like IO::Async, as long as those
63	as those use one of the supported event loops. It is trivial to add new	81	use one of the supported event loops. It is trivial to add new event loops
64	event loops to AnyEvent, too, so it is future-proof).	82	to AnyEvent, too, so it is future-proof).
65		83
66	In addition to being free of having to use I<the one and only true event	84	In addition to being free of having to use I<the one and only true event
67	model>, AnyEvent also is free of bloat and policy: with POE or similar	85	model>, AnyEvent also is free of bloat and policy: with POE or similar
68	modules, you get an enormous amount of code and strict rules you have to	86	modules, you get an enormous amount of code and strict rules you have to
69	follow. AnyEvent, on the other hand, is lean and up to the point, by only	87	follow. AnyEvent, on the other hand, is lean and up to the point, by only
…		…
127	These watchers are normal Perl objects with normal Perl lifetime. After	145	These watchers are normal Perl objects with normal Perl lifetime. After
128	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
129	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
130	is in control).	148	is in control).
131		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
132	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
133	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
134	to it).	158	to it).
135		159
136	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.
…		…
152	=head2 I/O WATCHERS	176	=head2 I/O WATCHERS
153		177
154	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
155	with the following mandatory key-value pairs as arguments:	179	with the following mandatory key-value pairs as arguments:
156		180
157	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	181	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch
		182	for events (AnyEvent might or might not keep a reference to this file
		183	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
158	for events. C<poll> must be a string that is either C<r> or C<w>,	188	C<poll> must be a string that is either C<r> or C<w>, which creates a
159	which creates a watcher waiting for "r"eadable or "w"ritable events,	189	watcher waiting for "r"eadable or "w"ritable events, respectively.
		190
160	respectively. C<cb> is the callback to invoke each time the file handle	191	C<cb> is the callback to invoke each time the file handle becomes ready.
161	becomes ready.
162		192
163	Although the callback might get passed parameters, their value and	193	Although the callback might get passed parameters, their value and
164	presence is undefined and you cannot rely on them. Portable AnyEvent	194	presence is undefined and you cannot rely on them. Portable AnyEvent
165	callbacks cannot use arguments passed to I/O watcher callbacks.	195	callbacks cannot use arguments passed to I/O watcher callbacks.
166		196
…		…
193	Although the callback might get passed parameters, their value and	223	Although the callback might get passed parameters, their value and
194	presence is undefined and you cannot rely on them. Portable AnyEvent	224	presence is undefined and you cannot rely on them. Portable AnyEvent
195	callbacks cannot use arguments passed to time watcher callbacks.	225	callbacks cannot use arguments passed to time watcher callbacks.
196		226
197	The callback will normally be invoked once only. If you specify another	227	The callback will normally be invoked once only. If you specify another
198	parameter, C<interval>, as a positive number, then the callback will be	228	parameter, C<interval>, as a strictly positive number (> 0), then the
199	invoked regularly at that interval (in fractional seconds) after the first	229	callback will be invoked regularly at that interval (in fractional
200	invocation.	230	seconds) after the first invocation. If C<interval> is specified with a
		231	false value, then it is treated as if it were missing.
201		232
202	The callback will be rescheduled before invoking the callback, but no	233	The callback will be rescheduled before invoking the callback, but no
203	attempt is done to avoid timer drift in most backends, so the interval is	234	attempt is done to avoid timer drift in most backends, so the interval is
204	only approximate.	235	only approximate.
205		236
…		…
297	In either case, if you care (and in most cases, you don't), then you	328	In either case, if you care (and in most cases, you don't), then you
298	can get whatever behaviour you want with any event loop, by taking the	329	can get whatever behaviour you want with any event loop, by taking the
299	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	330	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
300	account.	331	account.
301		332
		333	=item AnyEvent->now_update
		334
		335	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		336	the current time for each loop iteration (see the discussion of L<<
		337	AnyEvent->now >>, above).
		338
		339	When a callback runs for a long time (or when the process sleeps), then
		340	this "current" time will differ substantially from the real time, which
		341	might affect timers and time-outs.
		342
		343	When this is the case, you can call this method, which will update the
		344	event loop's idea of "current time".
		345
		346	Note that updating the time I<might> cause some events to be handled.
		347
302	=back	348	=back
303		349
304	=head2 SIGNAL WATCHERS	350	=head2 SIGNAL WATCHERS
305		351
306	You can watch for signals using a signal watcher, C<signal> is the signal	352	You can watch for signals using a signal watcher, C<signal> is the signal
307	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to	353	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
308	be invoked whenever a signal occurs.	354	callback to be invoked whenever a signal occurs.
309		355
310	Although the callback might get passed parameters, their value and	356	Although the callback might get passed parameters, their value and
311	presence is undefined and you cannot rely on them. Portable AnyEvent	357	presence is undefined and you cannot rely on them. Portable AnyEvent
312	callbacks cannot use arguments passed to signal watcher callbacks.	358	callbacks cannot use arguments passed to signal watcher callbacks.
313		359
…		…
329	=head2 CHILD PROCESS WATCHERS	375	=head2 CHILD PROCESS WATCHERS
330		376
331	You can also watch on a child process exit and catch its exit status.	377	You can also watch on a child process exit and catch its exit status.
332		378
333	The child process is specified by the C<pid> argument (if set to C<0>, it	379	The child process is specified by the C<pid> argument (if set to C<0>, it
334	watches for any child process exit). The watcher will trigger as often	380	watches for any child process exit). The watcher will triggered only when
335	as status change for the child are received. This works by installing a	381	the child process has finished and an exit status is available, not on
336	signal handler for C<SIGCHLD>. The callback will be called with the pid	382	any trace events (stopped/continued).
337	and exit status (as returned by waitpid), so unlike other watcher types,	383
338	you I<can> rely on child watcher callback arguments.	384	The callback will be called with the pid and exit status (as returned by
		385	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		386	callback arguments.
		387
		388	This watcher type works by installing a signal handler for C<SIGCHLD>,
		389	and since it cannot be shared, nothing else should use SIGCHLD or reap
		390	random child processes (waiting for specific child processes, e.g. inside
		391	C<system>, is just fine).
339		392
340	There is a slight catch to child watchers, however: you usually start them	393	There is a slight catch to child watchers, however: you usually start them
341	I<after> the child process was created, and this means the process could	394	I<after> the child process was created, and this means the process could
342	have exited already (and no SIGCHLD will be sent anymore).	395	have exited already (and no SIGCHLD will be sent anymore).
343		396
344	Not all event models handle this correctly (POE doesn't), but even for	397	Not all event models handle this correctly (neither POE nor IO::Async do,
		398	see their AnyEvent::Impl manpages for details), but even for event models
345	event models that I<do> handle this correctly, they usually need to be	399	that I<do> handle this correctly, they usually need to be loaded before
346	loaded before the process exits (i.e. before you fork in the first place).	400	the process exits (i.e. before you fork in the first place). AnyEvent's
		401	pure perl event loop handles all cases correctly regardless of when you
		402	start the watcher.
347		403
348	This means you cannot create a child watcher as the very first thing in an	404	This means you cannot create a child watcher as the very first
349	AnyEvent program, you I<have> to create at least one watcher before you	405	thing in an AnyEvent program, you I<have> to create at least one
350	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	406	watcher before you C<fork> the child (alternatively, you can call
		407	C<AnyEvent::detect>).
351		408
352	Example: fork a process and wait for it	409	Example: fork a process and wait for it
353		410
354	my $done = AnyEvent->condvar;	411	my $done = AnyEvent->condvar;
355		412
…		…
365	);	422	);
366		423
367	# do something else, then wait for process exit	424	# do something else, then wait for process exit
368	$done->recv;	425	$done->recv;
369		426
		427	=head2 IDLE WATCHERS
		428
		429	Sometimes there is a need to do something, but it is not so important
		430	to do it instantly, but only when there is nothing better to do. This
		431	"nothing better to do" is usually defined to be "no other events need
		432	attention by the event loop".
		433
		434	Idle watchers ideally get invoked when the event loop has nothing
		435	better to do, just before it would block the process to wait for new
		436	events. Instead of blocking, the idle watcher is invoked.
		437
		438	Most event loops unfortunately do not really support idle watchers (only
		439	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		440	will simply call the callback "from time to time".
		441
		442	Example: read lines from STDIN, but only process them when the
		443	program is otherwise idle:
		444
		445	my @lines; # read data
		446	my $idle_w;
		447	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		448	push @lines, scalar <STDIN>;
		449
		450	# start an idle watcher, if not already done
		451	$idle_w \|\|= AnyEvent->idle (cb => sub {
		452	# handle only one line, when there are lines left
		453	if (my $line = shift @lines) {
		454	print "handled when idle: $line";
		455	} else {
		456	# otherwise disable the idle watcher again
		457	undef $idle_w;
		458	}
		459	});
		460	});
		461
370	=head2 CONDITION VARIABLES	462	=head2 CONDITION VARIABLES
371		463
372	If you are familiar with some event loops you will know that all of them	464	If you are familiar with some event loops you will know that all of them
373	require you to run some blocking "loop", "run" or similar function that	465	require you to run some blocking "loop", "run" or similar function that
374	will actively watch for new events and call your callbacks.	466	will actively watch for new events and call your callbacks.
…		…
379	The instrument to do that is called a "condition variable", so called	471	The instrument to do that is called a "condition variable", so called
380	because they represent a condition that must become true.	472	because they represent a condition that must become true.
381		473
382	Condition variables can be created by calling the C<< AnyEvent->condvar	474	Condition variables can be created by calling the C<< AnyEvent->condvar
383	>> method, usually without arguments. The only argument pair allowed is	475	>> method, usually without arguments. The only argument pair allowed is
		476
384	C<cb>, which specifies a callback to be called when the condition variable	477	C<cb>, which specifies a callback to be called when the condition variable
385	becomes true.	478	becomes true, with the condition variable as the first argument (but not
		479	the results).
386		480
387	After creation, the condition variable is "false" until it becomes "true"	481	After creation, the condition variable is "false" until it becomes "true"
388	by calling the C<send> method (or calling the condition variable as if it	482	by calling the C<send> method (or calling the condition variable as if it
389	were a callback, read about the caveats in the description for the C<<	483	were a callback, read about the caveats in the description for the C<<
390	->send >> method).	484	->send >> method).
…		…
446		540
447	my $done = AnyEvent->condvar;	541	my $done = AnyEvent->condvar;
448	my $delay = AnyEvent->timer (after => 5, cb => $done);	542	my $delay = AnyEvent->timer (after => 5, cb => $done);
449	$done->recv;	543	$done->recv;
450		544
		545	Example: Imagine an API that returns a condvar and doesn't support
		546	callbacks. This is how you make a synchronous call, for example from
		547	the main program:
		548
		549	use AnyEvent::CouchDB;
		550
		551	...
		552
		553	my @info = $couchdb->info->recv;
		554
		555	And this is how you would just ste a callback to be called whenever the
		556	results are available:
		557
		558	$couchdb->info->cb (sub {
		559	my @info = $_[0]->recv;
		560	});
		561
451	=head3 METHODS FOR PRODUCERS	562	=head3 METHODS FOR PRODUCERS
452		563
453	These methods should only be used by the producing side, i.e. the	564	These methods should only be used by the producing side, i.e. the
454	code/module that eventually sends the signal. Note that it is also	565	code/module that eventually sends the signal. Note that it is also
455	the producer side which creates the condvar in most cases, but it isn't	566	the producer side which creates the condvar in most cases, but it isn't
…		…
588	=item $bool = $cv->ready	699	=item $bool = $cv->ready
589		700
590	Returns true when the condition is "true", i.e. whether C<send> or	701	Returns true when the condition is "true", i.e. whether C<send> or
591	C<croak> have been called.	702	C<croak> have been called.
592		703
593	=item $cb = $cv->cb ([new callback])	704	=item $cb = $cv->cb ($cb->($cv))
594		705
595	This is a mutator function that returns the callback set and optionally	706	This is a mutator function that returns the callback set and optionally
596	replaces it before doing so.	707	replaces it before doing so.
597		708
598	The callback will be called when the condition becomes "true", i.e. when	709	The callback will be called when the condition becomes "true", i.e. when
…		…
623	AnyEvent::Impl::Tk based on Tk, very bad choice.	734	AnyEvent::Impl::Tk based on Tk, very bad choice.
624	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).	735	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
625	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	736	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
626	AnyEvent::Impl::POE based on POE, not generic enough for full support.	737	AnyEvent::Impl::POE based on POE, not generic enough for full support.
627		738
		739	# warning, support for IO::Async is only partial, as it is too broken
		740	# and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
		741	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
		742
628	There is no support for WxWidgets, as WxWidgets has no support for	743	There is no support for WxWidgets, as WxWidgets has no support for
629	watching file handles. However, you can use WxWidgets through the	744	watching file handles. However, you can use WxWidgets through the
630	POE Adaptor, as POE has a Wx backend that simply polls 20 times per	745	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
631	second, which was considered to be too horrible to even consider for	746	second, which was considered to be too horrible to even consider for
632	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using	747	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
…		…
788	=item L<AnyEvent::IGS>	903	=item L<AnyEvent::IGS>
789		904
790	A non-blocking interface to the Internet Go Server protocol (used by	905	A non-blocking interface to the Internet Go Server protocol (used by
791	L<App::IGS>).	906	L<App::IGS>).
792		907
793	=item L<Net::IRC3>	908	=item L<AnyEvent::IRC>
794		909
795	AnyEvent based IRC client module family.	910	AnyEvent based IRC client module family (replacing the older Net::IRC3).
796		911
797	=item L<Net::XMPP2>	912	=item L<Net::XMPP2>
798		913
799	AnyEvent based XMPP (Jabber protocol) module family.	914	AnyEvent based XMPP (Jabber protocol) module family.
800		915
…		…
820	=cut	935	=cut
821		936
822	package AnyEvent;	937	package AnyEvent;
823		938
824	no warnings;	939	no warnings;
825	use strict;	940	use strict qw(vars subs);
826		941
827	use Carp;	942	use Carp;
828		943
829	our $VERSION = 4.2;	944	our $VERSION = 4.412;
830	our $MODEL;	945	our $MODEL;
831		946
832	our $AUTOLOAD;	947	our $AUTOLOAD;
833	our @ISA;	948	our @ISA;
834		949
835	our @REGISTRY;	950	our @REGISTRY;
836		951
837	our $WIN32;	952	our $WIN32;
838		953
839	BEGIN {	954	BEGIN {
840	my $win32 = ! ! ($^O =~ /mswin32/i);	955	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
841	eval "sub WIN32(){ $win32 }";	956	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
		957
		958	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		959	if ${^TAINT};
842	}	960	}
843		961
844	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	962	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
845		963
846	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred	964	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
…		…
864	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	982	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
865	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	983	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
866	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	984	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
867	[Wx:: => AnyEvent::Impl::POE::],	985	[Wx:: => AnyEvent::Impl::POE::],
868	[Prima:: => AnyEvent::Impl::POE::],	986	[Prima:: => AnyEvent::Impl::POE::],
		987	# IO::Async is just too broken - we would need workaorunds for its
		988	# byzantine signal and broken child handling, among others.
		989	# IO::Async is rather hard to detect, as it doesn't have any
		990	# obvious default class.
		991	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		992	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		993	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
869	);	994	);
870		995
871	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	996	our %method = map +($_ => 1),
		997	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
872		998
873	our @post_detect;	999	our @post_detect;
874		1000
875	sub post_detect(&) {	1001	sub post_detect(&) {
876	my ($cb) = @_;	1002	my ($cb) = @_;
…		…
881	1	1007	1
882	} else {	1008	} else {
883	push @post_detect, $cb;	1009	push @post_detect, $cb;
884		1010
885	defined wantarray	1011	defined wantarray
886	? bless \$cb, "AnyEvent::Util::PostDetect"	1012	? bless \$cb, "AnyEvent::Util::postdetect"
887	: ()	1013	: ()
888	}	1014	}
889	}	1015	}
890		1016
891	sub AnyEvent::Util::PostDetect::DESTROY {	1017	sub AnyEvent::Util::postdetect::DESTROY {
892	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1018	@post_detect = grep $_ != ${$_[0]}, @post_detect;
893	}	1019	}
894		1020
895	sub detect() {	1021	sub detect() {
896	unless ($MODEL) {	1022	unless ($MODEL) {
…		…
933	last;	1059	last;
934	}	1060	}
935	}	1061	}
936		1062
937	$MODEL	1063	$MODEL
938	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1064	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
939	}	1065	}
940	}	1066	}
941		1067
		1068	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1069
942	unshift @ISA, $MODEL;	1070	unshift @ISA, $MODEL;
943	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1071
		1072	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
944		1073
945	(shift @post_detect)->() while @post_detect;	1074	(shift @post_detect)->() while @post_detect;
946	}	1075	}
947		1076
948	$MODEL	1077	$MODEL
…		…
958		1087
959	my $class = shift;	1088	my $class = shift;
960	$class->$func (@_);	1089	$class->$func (@_);
961	}	1090	}
962		1091
		1092	# utility function to dup a filehandle. this is used by many backends
		1093	# to support binding more than one watcher per filehandle (they usually
		1094	# allow only one watcher per fd, so we dup it to get a different one).
		1095	sub _dupfh($$;$$) {
		1096	my ($poll, $fh, $r, $w) = @_;
		1097
		1098	# cygwin requires the fh mode to be matching, unix doesn't
		1099	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		1100	: $poll eq "w" ? ($w, ">")
		1101	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		1102
		1103	open my $fh2, "$mode&" . fileno $fh
		1104	or die "cannot dup() filehandle: $!,";
		1105
		1106	# we assume CLOEXEC is already set by perl in all important cases
		1107
		1108	($fh2, $rw)
		1109	}
		1110
963	package AnyEvent::Base;	1111	package AnyEvent::Base;
964		1112
965	# default implementation for now and time	1113	# default implementations for many methods
966		1114
967	use Time::HiRes ();	1115	BEGIN {
		1116	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1117	*_time = \&Time::HiRes::time;
		1118	# if (eval "use POSIX (); (POSIX::times())...
		1119	} else {
		1120	*_time = sub { time }; # epic fail
		1121	}
		1122	}
968		1123
969	sub time { Time::HiRes::time }	1124	sub time { _time }
970	sub now { Time::HiRes::time }	1125	sub now { _time }
		1126	sub now_update { }
971		1127
972	# default implementation for ->condvar	1128	# default implementation for ->condvar
973		1129
974	sub condvar {	1130	sub condvar {
975	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1131	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
976	}	1132	}
977		1133
978	# default implementation for ->signal	1134	# default implementation for ->signal
979		1135
980	our %SIG_CB;	1136	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1137
		1138	sub _signal_exec {
		1139	sysread $SIGPIPE_R, my $dummy, 4;
		1140
		1141	while (%SIG_EV) {
		1142	for (keys %SIG_EV) {
		1143	delete $SIG_EV{$_};
		1144	$_->() for values %{ $SIG_CB{$_} \|\| {} };
		1145	}
		1146	}
		1147	}
981		1148
982	sub signal {	1149	sub signal {
983	my (undef, %arg) = @_;	1150	my (undef, %arg) = @_;
984		1151
		1152	unless ($SIGPIPE_R) {
		1153	require Fcntl;
		1154
		1155	if (AnyEvent::WIN32) {
		1156	require AnyEvent::Util;
		1157
		1158	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1159	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1160	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1161	} else {
		1162	pipe $SIGPIPE_R, $SIGPIPE_W;
		1163	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1164	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1165
		1166	# not strictly required, as $^F is normally 2, but let's make sure...
		1167	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1168	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1169	}
		1170
		1171	$SIGPIPE_R
		1172	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1173
		1174	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1175	}
		1176
985	my $signal = uc $arg{signal}	1177	my $signal = uc $arg{signal}
986	or Carp::croak "required option 'signal' is missing";	1178	or Carp::croak "required option 'signal' is missing";
987		1179
988	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1180	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
989	$SIG{$signal} \|\|= sub {	1181	$SIG{$signal} \|\|= sub {
990	$_->() for values %{ $SIG_CB{$signal} \|\| {} };	1182	local $!;
		1183	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1184	undef $SIG_EV{$signal};
991	};	1185	};
992		1186
993	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1187	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
994	}	1188	}
995		1189
996	sub AnyEvent::Base::Signal::DESTROY {	1190	sub AnyEvent::Base::signal::DESTROY {
997	my ($signal, $cb) = @{$_[0]};	1191	my ($signal, $cb) = @{$_[0]};
998		1192
999	delete $SIG_CB{$signal}{$cb};	1193	delete $SIG_CB{$signal}{$cb};
1000		1194
		1195	# delete doesn't work with older perls - they then
		1196	# print weird messages, or just unconditionally exit
		1197	# instead of getting the default action.
1001	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };	1198	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1002	}	1199	}
1003		1200
1004	# default implementation for ->child	1201	# default implementation for ->child
1005		1202
1006	our %PID_CB;	1203	our %PID_CB;
1007	our $CHLD_W;	1204	our $CHLD_W;
1008	our $CHLD_DELAY_W;	1205	our $CHLD_DELAY_W;
1009	our $PID_IDLE;
1010	our $WNOHANG;	1206	our $WNOHANG;
1011		1207
1012	sub _child_wait {	1208	sub _sigchld {
1013	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1209	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1014	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),	1210	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),
1015	(values %{ $PID_CB{0} \|\| {} });	1211	(values %{ $PID_CB{0} \|\| {} });
1016	}	1212	}
1017
1018	undef $PID_IDLE;
1019	}
1020
1021	sub _sigchld {
1022	# make sure we deliver these changes "synchronous" with the event loop.
1023	$CHLD_DELAY_W \|\|= AnyEvent->timer (after => 0, cb => sub {
1024	undef $CHLD_DELAY_W;
1025	&_child_wait;
1026	});
1027	}	1213	}
1028		1214
1029	sub child {	1215	sub child {
1030	my (undef, %arg) = @_;	1216	my (undef, %arg) = @_;
1031		1217
1032	defined (my $pid = $arg{pid} + 0)	1218	defined (my $pid = $arg{pid} + 0)
1033	or Carp::croak "required option 'pid' is missing";	1219	or Carp::croak "required option 'pid' is missing";
1034		1220
1035	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1221	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1036		1222
1037	unless ($WNOHANG) {
1038	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;	1223	$WNOHANG \|\|= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
1039	}
1040		1224
1041	unless ($CHLD_W) {	1225	unless ($CHLD_W) {
1042	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1226	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1043	# child could be a zombie already, so make at least one round	1227	# child could be a zombie already, so make at least one round
1044	&_sigchld;	1228	&_sigchld;
1045	}	1229	}
1046		1230
1047	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1231	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1048	}	1232	}
1049		1233
1050	sub AnyEvent::Base::Child::DESTROY {	1234	sub AnyEvent::Base::child::DESTROY {
1051	my ($pid, $cb) = @{$_[0]};	1235	my ($pid, $cb) = @{$_[0]};
1052		1236
1053	delete $PID_CB{$pid}{$cb};	1237	delete $PID_CB{$pid}{$cb};
1054	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1238	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1055		1239
1056	undef $CHLD_W unless keys %PID_CB;	1240	undef $CHLD_W unless keys %PID_CB;
		1241	}
		1242
		1243	# idle emulation is done by simply using a timer, regardless
		1244	# of whether the process is idle or not, and not letting
		1245	# the callback use more than 50% of the time.
		1246	sub idle {
		1247	my (undef, %arg) = @_;
		1248
		1249	my ($cb, $w, $rcb) = $arg{cb};
		1250
		1251	$rcb = sub {
		1252	if ($cb) {
		1253	$w = _time;
		1254	&$cb;
		1255	$w = _time - $w;
		1256
		1257	# never use more then 50% of the time for the idle watcher,
		1258	# within some limits
		1259	$w = 0.0001 if $w < 0.0001;
		1260	$w = 5 if $w > 5;
		1261
		1262	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1263	} else {
		1264	# clean up...
		1265	undef $w;
		1266	undef $rcb;
		1267	}
		1268	};
		1269
		1270	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1271
		1272	bless \\$cb, "AnyEvent::Base::idle"
		1273	}
		1274
		1275	sub AnyEvent::Base::idle::DESTROY {
		1276	undef $${$_[0]};
1057	}	1277	}
1058		1278
1059	package AnyEvent::CondVar;	1279	package AnyEvent::CondVar;
1060		1280
1061	our @ISA = AnyEvent::CondVar::Base::;	1281	our @ISA = AnyEvent::CondVar::Base::;
…		…
1113	}	1333	}
1114		1334
1115	# undocumented/compatibility with pre-3.4	1335	# undocumented/compatibility with pre-3.4
1116	*broadcast = \&send;	1336	*broadcast = \&send;
1117	*wait = \&_wait;	1337	*wait = \&_wait;
		1338
		1339	=head1 ERROR AND EXCEPTION HANDLING
		1340
		1341	In general, AnyEvent does not do any error handling - it relies on the
		1342	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1343	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1344	checking of all AnyEvent methods, however, which is highly useful during
		1345	development.
		1346
		1347	As for exception handling (i.e. runtime errors and exceptions thrown while
		1348	executing a callback), this is not only highly event-loop specific, but
		1349	also not in any way wrapped by this module, as this is the job of the main
		1350	program.
		1351
		1352	The pure perl event loop simply re-throws the exception (usually
		1353	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1354	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1355	so on.
		1356
		1357	=head1 ENVIRONMENT VARIABLES
		1358
		1359	The following environment variables are used by this module or its
		1360	submodules.
		1361
		1362	Note that AnyEvent will remove I<all> environment variables starting with
		1363	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1364	enabled.
		1365
		1366	=over 4
		1367
		1368	=item C<PERL_ANYEVENT_VERBOSE>
		1369
		1370	By default, AnyEvent will be completely silent except in fatal
		1371	conditions. You can set this environment variable to make AnyEvent more
		1372	talkative.
		1373
		1374	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1375	conditions, such as not being able to load the event model specified by
		1376	C<PERL_ANYEVENT_MODEL>.
		1377
		1378	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1379	model it chooses.
		1380
		1381	=item C<PERL_ANYEVENT_STRICT>
		1382
		1383	AnyEvent does not do much argument checking by default, as thorough
		1384	argument checking is very costly. Setting this variable to a true value
		1385	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1386	check the arguments passed to most method calls. If it finds any problems,
		1387	it will croak.
		1388
		1389	In other words, enables "strict" mode.
		1390
		1391	Unlike C<use strict>, it is definitely recommended to keep it off in
		1392	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1393	developing programs can be very useful, however.
		1394
		1395	=item C<PERL_ANYEVENT_MODEL>
		1396
		1397	This can be used to specify the event model to be used by AnyEvent, before
		1398	auto detection and -probing kicks in. It must be a string consisting
		1399	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1400	and the resulting module name is loaded and if the load was successful,
		1401	used as event model. If it fails to load AnyEvent will proceed with
		1402	auto detection and -probing.
		1403
		1404	This functionality might change in future versions.
		1405
		1406	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1407	could start your program like this:
		1408
		1409	PERL_ANYEVENT_MODEL=Perl perl ...
		1410
		1411	=item C<PERL_ANYEVENT_PROTOCOLS>
		1412
		1413	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1414	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1415	of auto probing).
		1416
		1417	Must be set to a comma-separated list of protocols or address families,
		1418	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1419	used, and preference will be given to protocols mentioned earlier in the
		1420	list.
		1421
		1422	This variable can effectively be used for denial-of-service attacks
		1423	against local programs (e.g. when setuid), although the impact is likely
		1424	small, as the program has to handle conenction and other failures anyways.
		1425
		1426	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1427	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1428	- only support IPv4, never try to resolve or contact IPv6
		1429	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1430	IPv6, but prefer IPv6 over IPv4.
		1431
		1432	=item C<PERL_ANYEVENT_EDNS0>
		1433
		1434	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1435	for DNS. This extension is generally useful to reduce DNS traffic, but
		1436	some (broken) firewalls drop such DNS packets, which is why it is off by
		1437	default.
		1438
		1439	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1440	EDNS0 in its DNS requests.
		1441
		1442	=item C<PERL_ANYEVENT_MAX_FORKS>
		1443
		1444	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1445	will create in parallel.
		1446
		1447	=back
1118		1448
1119	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1449	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1120		1450
1121	This is an advanced topic that you do not normally need to use AnyEvent in	1451	This is an advanced topic that you do not normally need to use AnyEvent in
1122	a module. This section is only of use to event loop authors who want to	1452	a module. This section is only of use to event loop authors who want to
…		…
1156		1486
1157	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1487	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1158	condition variables: code blocking while waiting for a condition will	1488	condition variables: code blocking while waiting for a condition will
1159	C<die>. This still works with most modules/usages, and blocking calls must	1489	C<die>. This still works with most modules/usages, and blocking calls must
1160	not be done in an interactive application, so it makes sense.	1490	not be done in an interactive application, so it makes sense.
1161
1162	=head1 ENVIRONMENT VARIABLES
1163
1164	The following environment variables are used by this module:
1165
1166	=over 4
1167
1168	=item C<PERL_ANYEVENT_VERBOSE>
1169
1170	By default, AnyEvent will be completely silent except in fatal
1171	conditions. You can set this environment variable to make AnyEvent more
1172	talkative.
1173
1174	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1175	conditions, such as not being able to load the event model specified by
1176	C<PERL_ANYEVENT_MODEL>.
1177
1178	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1179	model it chooses.
1180
1181	=item C<PERL_ANYEVENT_MODEL>
1182
1183	This can be used to specify the event model to be used by AnyEvent, before
1184	auto detection and -probing kicks in. It must be a string consisting
1185	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1186	and the resulting module name is loaded and if the load was successful,
1187	used as event model. If it fails to load AnyEvent will proceed with
1188	auto detection and -probing.
1189
1190	This functionality might change in future versions.
1191
1192	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1193	could start your program like this:
1194
1195	PERL_ANYEVENT_MODEL=Perl perl ...
1196
1197	=item C<PERL_ANYEVENT_PROTOCOLS>
1198
1199	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1200	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1201	of auto probing).
1202
1203	Must be set to a comma-separated list of protocols or address families,
1204	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1205	used, and preference will be given to protocols mentioned earlier in the
1206	list.
1207
1208	This variable can effectively be used for denial-of-service attacks
1209	against local programs (e.g. when setuid), although the impact is likely
1210	small, as the program has to handle connection errors already-
1211
1212	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1213	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1214	- only support IPv4, never try to resolve or contact IPv6
1215	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1216	IPv6, but prefer IPv6 over IPv4.
1217
1218	=item C<PERL_ANYEVENT_EDNS0>
1219
1220	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1221	for DNS. This extension is generally useful to reduce DNS traffic, but
1222	some (broken) firewalls drop such DNS packets, which is why it is off by
1223	default.
1224
1225	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1226	EDNS0 in its DNS requests.
1227
1228	=item C<PERL_ANYEVENT_MAX_FORKS>
1229
1230	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1231	will create in parallel.
1232
1233	=back
1234		1491
1235	=head1 EXAMPLE PROGRAM	1492	=head1 EXAMPLE PROGRAM
1236		1493
1237	The following program uses an I/O watcher to read data from STDIN, a timer	1494	The following program uses an I/O watcher to read data from STDIN, a timer
1238	to display a message once per second, and a condition variable to quit the	1495	to display a message once per second, and a condition variable to quit the
…		…
1432	watcher.	1689	watcher.
1433		1690
1434	=head3 Results	1691	=head3 Results
1435		1692
1436	name watchers bytes create invoke destroy comment	1693	name watchers bytes create invoke destroy comment
1437	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1694	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1438	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1695	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1439	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1696	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1440	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1697	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1441	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1698	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1442	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	1699	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1443	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1700	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1444	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1701	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1445	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1702	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1446	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1703	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1447		1704
1448	=head3 Discussion	1705	=head3 Discussion
1449		1706
1450	The benchmark does I<not> measure scalability of the event loop very	1707	The benchmark does I<not> measure scalability of the event loop very
1451	well. For example, a select-based event loop (such as the pure perl one)	1708	well. For example, a select-based event loop (such as the pure perl one)
…		…
1652	=item * C-based event loops perform very well with small number of	1909	=item * C-based event loops perform very well with small number of
1653	watchers, as the management overhead dominates.	1910	watchers, as the management overhead dominates.
1654		1911
1655	=back	1912	=back
1656		1913
		1914	=head2 THE IO::Lambda BENCHMARK
		1915
		1916	Recently I was told about the benchmark in the IO::Lambda manpage, which
		1917	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		1918	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		1919	shouldn't come as a surprise to anybody). As such, the benchmark is
		1920	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		1921	very optimal. But how would AnyEvent compare when used without the extra
		1922	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		1923
		1924	The benchmark itself creates an echo-server, and then, for 500 times,
		1925	connects to the echo server, sends a line, waits for the reply, and then
		1926	creates the next connection. This is a rather bad benchmark, as it doesn't
		1927	test the efficiency of the framework or much non-blocking I/O, but it is a
		1928	benchmark nevertheless.
		1929
		1930	name runtime
		1931	Lambda/select 0.330 sec
		1932	+ optimized 0.122 sec
		1933	Lambda/AnyEvent 0.327 sec
		1934	+ optimized 0.138 sec
		1935	Raw sockets/select 0.077 sec
		1936	POE/select, components 0.662 sec
		1937	POE/select, raw sockets 0.226 sec
		1938	POE/select, optimized 0.404 sec
		1939
		1940	AnyEvent/select/nb 0.085 sec
		1941	AnyEvent/EV/nb 0.068 sec
		1942	+state machine 0.134 sec
		1943
		1944	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		1945	benchmarks actually make blocking connects and use 100% blocking I/O,
		1946	defeating the purpose of an event-based solution. All of the newly
		1947	written AnyEvent benchmarks use 100% non-blocking connects (using
		1948	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		1949	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		1950	generally require a lot more bookkeeping and event handling than blocking
		1951	connects (which involve a single syscall only).
		1952
		1953	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		1954	offers similar expressive power as POE and IO::Lambda, using conventional
		1955	Perl syntax. This means that both the echo server and the client are 100%
		1956	non-blocking, further placing it at a disadvantage.
		1957
		1958	As you can see, the AnyEvent + EV combination even beats the
		1959	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		1960	backend easily beats IO::Lambda and POE.
		1961
		1962	And even the 100% non-blocking version written using the high-level (and
		1963	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		1964	large margin, even though it does all of DNS, tcp-connect and socket I/O
		1965	in a non-blocking way.
		1966
		1967	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		1968	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		1969	part of the IO::lambda distribution and were used without any changes.
		1970
		1971
		1972	=head1 SIGNALS
		1973
		1974	AnyEvent currently installs handlers for these signals:
		1975
		1976	=over 4
		1977
		1978	=item SIGCHLD
		1979
		1980	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		1981	emulation for event loops that do not support them natively. Also, some
		1982	event loops install a similar handler.
		1983
		1984	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will
		1985	reset it to default, to avoid losing child exit statuses.
		1986
		1987	=item SIGPIPE
		1988
		1989	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		1990	when AnyEvent gets loaded.
		1991
		1992	The rationale for this is that AnyEvent users usually do not really depend
		1993	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		1994	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		1995	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		1996	some random socket.
		1997
		1998	The rationale for installing a no-op handler as opposed to ignoring it is
		1999	that this way, the handler will be restored to defaults on exec.
		2000
		2001	Feel free to install your own handler, or reset it to defaults.
		2002
		2003	=back
		2004
		2005	=cut
		2006
		2007	undef $SIG{CHLD}
		2008	if $SIG{CHLD} eq 'IGNORE';
		2009
		2010	$SIG{PIPE} = sub { }
		2011	unless defined $SIG{PIPE};
1657		2012
1658	=head1 FORK	2013	=head1 FORK
1659		2014
1660	Most event libraries are not fork-safe. The ones who are usually are	2015	Most event libraries are not fork-safe. The ones who are usually are
1661	because they rely on inefficient but fork-safe C<select> or C<poll>	2016	because they rely on inefficient but fork-safe C<select> or C<poll>
…		…
1681		2036
1682	use AnyEvent;	2037	use AnyEvent;
1683		2038
1684	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2039	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1685	be used to probe what backend is used and gain other information (which is	2040	be used to probe what backend is used and gain other information (which is
1686	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	2041	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		2042	$ENV{PERL_ANYEVENT_STRICT}.
		2043
		2044	Note that AnyEvent will remove I<all> environment variables starting with
		2045	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2046	enabled.
1687		2047
1688		2048
1689	=head1 BUGS	2049	=head1 BUGS
1690		2050
1691	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2051	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1692	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2052	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1693	and check wether the leaks still show up. (Perl 5.10.0 has other annoying	2053	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1694	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as	2054	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1695	pronounced).	2055	pronounced).
1696		2056
1697		2057
1698	=head1 SEE ALSO	2058	=head1 SEE ALSO
1699		2059

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.164 by root, Tue Jul 8 19:50:25 2008 UTC vs. Revision 1.219 by root, Thu Jun 25 11:16:08 2009 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.164 by root, Tue Jul 8 19:50:25 2008 UTC vs.
Revision 1.219 by root, Thu Jun 25 11:16:08 2009 UTC