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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.173 by root, Mon Jul 21 03:47:22 2008 UTC vs.
Revision 1.229 by root, Wed Jul 8 02:01:12 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 { ... });
12		14
		15	# one-shot or repeating timers
13	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
14	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
15		18
16	print AnyEvent->now; # prints current event loop time	19	print AnyEvent->now; # prints current event loop time
17	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
18		21
		22	# POSIX signal
19	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });	23	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
20		24
		25	# child process exit
21	my $w = AnyEvent->child (pid => $pid, cb => sub {	26	my $w = AnyEvent->child (pid => $pid, cb => sub {
22	my ($pid, $status) = @_;	27	my ($pid, $status) = @_;
23	...	28	...
24	});	29	});
		30
		31	# called when event loop idle (if applicable)
		32	my $w = AnyEvent->idle (cb => sub { ... });
25		33
26	my $w = AnyEvent->condvar; # stores whether a condition was flagged	34	my $w = AnyEvent->condvar; # stores whether a condition was flagged
27	$w->send; # wake up current and all future recv's	35	$w->send; # wake up current and all future recv's
28	$w->recv; # enters "main loop" till $condvar gets ->send	36	$w->recv; # enters "main loop" till $condvar gets ->send
29	# use a condvar in callback mode:	37	# use a condvar in callback mode:
137	These watchers are normal Perl objects with normal Perl lifetime. After	145	These watchers are normal Perl objects with normal Perl lifetime. After
138	creating a watcher it will immediately "watch" for events and invoke the	146	creating a watcher it will immediately "watch" for events and invoke the
139	callback when the event occurs (of course, only when the event model	147	callback when the event occurs (of course, only when the event model
140	is in control).	148	is in control).
141		149
		150	Note that B<callbacks must not permanently change global variables>
		151	potentially in use by the event loop (such as C<$_> 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
142	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
143	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
144	to it).	158	to it).
145		159
146	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.
…		…
162	=head2 I/O WATCHERS	176	=head2 I/O WATCHERS
163		177
164	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
165	with the following mandatory key-value pairs as arguments:	179	with the following mandatory key-value pairs as arguments:
166		180
167	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events	181	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
168	(AnyEvent might or might not keep a reference to this file handle). C<poll>	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
169	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
170	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
171	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.
172		192
173	Although the callback might get passed parameters, their value and	193	Although the callback might get passed parameters, their value and
174	presence is undefined and you cannot rely on them. Portable AnyEvent	194	presence is undefined and you cannot rely on them. Portable AnyEvent
175	callbacks cannot use arguments passed to I/O watcher callbacks.	195	callbacks cannot use arguments passed to I/O watcher callbacks.
176		196
…		…
308	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
309	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
310	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	330	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
311	account.	331	account.
312		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
313	=back	348	=back
314		349
315	=head2 SIGNAL WATCHERS	350	=head2 SIGNAL WATCHERS
316		351
317	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
…		…
340	=head2 CHILD PROCESS WATCHERS	375	=head2 CHILD PROCESS WATCHERS
341		376
342	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.
343		378
344	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
345	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
346	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
347	signal handler for C<SIGCHLD>. The callback will be called with the pid	382	any trace events (stopped/continued).
348	and exit status (as returned by waitpid), so unlike other watcher types,	383
349	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).
350		392
351	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
352	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
353	have exited already (and no SIGCHLD will be sent anymore).	395	have exited already (and no SIGCHLD will be sent anymore).
354		396
355	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
356	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
357	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.
358		403
359	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
360	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
361	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>).
362		408
363	Example: fork a process and wait for it	409	Example: fork a process and wait for it
364		410
365	my $done = AnyEvent->condvar;	411	my $done = AnyEvent->condvar;
366		412
…		…
376	);	422	);
377		423
378	# do something else, then wait for process exit	424	# do something else, then wait for process exit
379	$done->recv;	425	$done->recv;
380		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
381	=head2 CONDITION VARIABLES	462	=head2 CONDITION VARIABLES
382		463
383	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
384	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
385	will actively watch for new events and call your callbacks.	466	will actively watch for new events and call your callbacks.
…		…
389		470
390	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
391	because they represent a condition that must become true.	472	because they represent a condition that must become true.
392		473
393	Condition variables can be created by calling the C<< AnyEvent->condvar	474	Condition variables can be created by calling the C<< AnyEvent->condvar
394
395	>> method, usually without arguments. The only argument pair allowed is	475	>> method, usually without arguments. The only argument pair allowed is
396		476
397	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
398	becomes true, with the condition variable as the first argument (but not	478	becomes true, with the condition variable as the first argument (but not
399	the results).	479	the results).
…		…
519		599
520	=item $cv->begin ([group callback])	600	=item $cv->begin ([group callback])
521		601
522	=item $cv->end	602	=item $cv->end
523		603
524	These two methods are EXPERIMENTAL and MIGHT CHANGE.
525
526	These two methods can be used to combine many transactions/events into	604	These two methods can be used to combine many transactions/events into
527	one. For example, a function that pings many hosts in parallel might want	605	one. For example, a function that pings many hosts in parallel might want
528	to use a condition variable for the whole process.	606	to use a condition variable for the whole process.
529		607
530	Every call to C<< ->begin >> will increment a counter, and every call to	608	Every call to C<< ->begin >> will increment a counter, and every call to
531	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	609	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
532	>>, the (last) callback passed to C<begin> will be executed. That callback	610	>>, the (last) callback passed to C<begin> will be executed. That callback
533	is I<supposed> to call C<< ->send >>, but that is not required. If no	611	is I<supposed> to call C<< ->send >>, but that is not required. If no
534	callback was set, C<send> will be called without any arguments.	612	callback was set, C<send> will be called without any arguments.
535		613
536	Let's clarify this with the ping example:	614	You can think of C<< $cv->send >> giving you an OR condition (one call
		615	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		616	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		617
		618	Let's start with a simple example: you have two I/O watchers (for example,
		619	STDOUT and STDERR for a program), and you want to wait for both streams to
		620	close before activating a condvar:
		621
		622	my $cv = AnyEvent->condvar;
		623
		624	$cv->begin; # first watcher
		625	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		626	defined sysread $fh1, my $buf, 4096
		627	or $cv->end;
		628	});
		629
		630	$cv->begin; # second watcher
		631	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		632	defined sysread $fh2, my $buf, 4096
		633	or $cv->end;
		634	});
		635
		636	$cv->recv;
		637
		638	This works because for every event source (EOF on file handle), there is
		639	one call to C<begin>, so the condvar waits for all calls to C<end> before
		640	sending.
		641
		642	The ping example mentioned above is slightly more complicated, as the
		643	there are results to be passwd back, and the number of tasks that are
		644	begung can potentially be zero:
537		645
538	my $cv = AnyEvent->condvar;	646	my $cv = AnyEvent->condvar;
539		647
540	my %result;	648	my %result;
541	$cv->begin (sub { $cv->send (\%result) });	649	$cv->begin (sub { $cv->send (\%result) });
…		…
561	loop, which serves two important purposes: first, it sets the callback	669	loop, which serves two important purposes: first, it sets the callback
562	to be called once the counter reaches C<0>, and second, it ensures that	670	to be called once the counter reaches C<0>, and second, it ensures that
563	C<send> is called even when C<no> hosts are being pinged (the loop	671	C<send> is called even when C<no> hosts are being pinged (the loop
564	doesn't execute once).	672	doesn't execute once).
565		673
566	This is the general pattern when you "fan out" into multiple subrequests:	674	This is the general pattern when you "fan out" into multiple (but
567	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	675	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
568	is called at least once, and then, for each subrequest you start, call	676	the callback and ensure C<end> is called at least once, and then, for each
569	C<begin> and for each subrequest you finish, call C<end>.	677	subrequest you start, call C<begin> and for each subrequest you finish,
		678	call C<end>.
570		679
571	=back	680	=back
572		681
573	=head3 METHODS FOR CONSUMERS	682	=head3 METHODS FOR CONSUMERS
574		683
…		…
654	AnyEvent::Impl::Tk based on Tk, very bad choice.	763	AnyEvent::Impl::Tk based on Tk, very bad choice.
655	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).	764	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
656	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	765	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
657	AnyEvent::Impl::POE based on POE, not generic enough for full support.	766	AnyEvent::Impl::POE based on POE, not generic enough for full support.
658		767
		768	# warning, support for IO::Async is only partial, as it is too broken
		769	# and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
		770	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
		771
659	There is no support for WxWidgets, as WxWidgets has no support for	772	There is no support for WxWidgets, as WxWidgets has no support for
660	watching file handles. However, you can use WxWidgets through the	773	watching file handles. However, you can use WxWidgets through the
661	POE Adaptor, as POE has a Wx backend that simply polls 20 times per	774	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
662	second, which was considered to be too horrible to even consider for	775	second, which was considered to be too horrible to even consider for
663	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using	776	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
…		…
819	=item L<AnyEvent::IGS>	932	=item L<AnyEvent::IGS>
820		933
821	A non-blocking interface to the Internet Go Server protocol (used by	934	A non-blocking interface to the Internet Go Server protocol (used by
822	L<App::IGS>).	935	L<App::IGS>).
823		936
824	=item L<Net::IRC3>	937	=item L<AnyEvent::IRC>
825		938
826	AnyEvent based IRC client module family.	939	AnyEvent based IRC client module family (replacing the older Net::IRC3).
827		940
828	=item L<Net::XMPP2>	941	=item L<Net::XMPP2>
829		942
830	AnyEvent based XMPP (Jabber protocol) module family.	943	AnyEvent based XMPP (Jabber protocol) module family.
831		944
…		…
851	=cut	964	=cut
852		965
853	package AnyEvent;	966	package AnyEvent;
854		967
855	no warnings;	968	no warnings;
856	use strict;	969	use strict qw(vars subs);
857		970
858	use Carp;	971	use Carp;
859		972
860	our $VERSION = 4.22;	973	our $VERSION = 4.8;
861	our $MODEL;	974	our $MODEL;
862		975
863	our $AUTOLOAD;	976	our $AUTOLOAD;
864	our @ISA;	977	our @ISA;
865		978
866	our @REGISTRY;	979	our @REGISTRY;
867		980
868	our $WIN32;	981	our $WIN32;
869		982
870	BEGIN {	983	BEGIN {
871	my $win32 = ! ! ($^O =~ /mswin32/i);	984	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
872	eval "sub WIN32(){ $win32 }";	985	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
		986
		987	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		988	if ${^TAINT};
873	}	989	}
874		990
875	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	991	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
876		992
877	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred	993	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
…		…
895	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1011	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
896	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1012	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
897	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1013	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
898	[Wx:: => AnyEvent::Impl::POE::],	1014	[Wx:: => AnyEvent::Impl::POE::],
899	[Prima:: => AnyEvent::Impl::POE::],	1015	[Prima:: => AnyEvent::Impl::POE::],
		1016	# IO::Async is just too broken - we would need workaorunds for its
		1017	# byzantine signal and broken child handling, among others.
		1018	# IO::Async is rather hard to detect, as it doesn't have any
		1019	# obvious default class.
		1020	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1021	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1022	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
900	);	1023	);
901		1024
902	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1025	our %method = map +($_ => 1),
		1026	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
903		1027
904	our @post_detect;	1028	our @post_detect;
905		1029
906	sub post_detect(&) {	1030	sub post_detect(&) {
907	my ($cb) = @_;	1031	my ($cb) = @_;
…		…
912	1	1036	1
913	} else {	1037	} else {
914	push @post_detect, $cb;	1038	push @post_detect, $cb;
915		1039
916	defined wantarray	1040	defined wantarray
917	? bless \$cb, "AnyEvent::Util::PostDetect"	1041	? bless \$cb, "AnyEvent::Util::postdetect"
918	: ()	1042	: ()
919	}	1043	}
920	}	1044	}
921		1045
922	sub AnyEvent::Util::PostDetect::DESTROY {	1046	sub AnyEvent::Util::postdetect::DESTROY {
923	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1047	@post_detect = grep $_ != ${$_[0]}, @post_detect;
924	}	1048	}
925		1049
926	sub detect() {	1050	sub detect() {
927	unless ($MODEL) {	1051	unless ($MODEL) {
…		…
964	last;	1088	last;
965	}	1089	}
966	}	1090	}
967		1091
968	$MODEL	1092	$MODEL
969	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1093	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
970	}	1094	}
971	}	1095	}
972		1096
973	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1097	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
974		1098
…		…
995	}	1119	}
996		1120
997	# utility function to dup a filehandle. this is used by many backends	1121	# utility function to dup a filehandle. this is used by many backends
998	# to support binding more than one watcher per filehandle (they usually	1122	# to support binding more than one watcher per filehandle (they usually
999	# allow only one watcher per fd, so we dup it to get a different one).	1123	# allow only one watcher per fd, so we dup it to get a different one).
1000	sub _dupfh($$$$) {	1124	sub _dupfh($$;$$) {
1001	my ($poll, $fh, $r, $w) = @_;	1125	my ($poll, $fh, $r, $w) = @_;
1002		1126
1003	require Fcntl;
1004
1005	# cygwin requires the fh mode to be matching, unix doesn't	1127	# cygwin requires the fh mode to be matching, unix doesn't
1006	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1128	my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">");
1007	: $poll eq "w" ? ($w, ">")
1008	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1009		1129
1010	open my $fh2, "$mode&" . fileno $fh	1130	open my $fh2, "$mode&", $fh
1011	or die "cannot dup() filehandle: $!";	1131	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1012		1132
1013	# we assume CLOEXEC is already set by perl in all important cases	1133	# we assume CLOEXEC is already set by perl in all important cases
1014		1134
1015	($fh2, $rw)	1135	($fh2, $rw)
1016	}	1136	}
1017		1137
1018	package AnyEvent::Base;	1138	package AnyEvent::Base;
1019		1139
1020	# default implementation for now and time	1140	# default implementations for many methods
1021		1141
1022	use Time::HiRes ();	1142	BEGIN {
		1143	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1144	*_time = \&Time::HiRes::time;
		1145	# if (eval "use POSIX (); (POSIX::times())...
		1146	} else {
		1147	*_time = sub { time }; # epic fail
		1148	}
		1149	}
1023		1150
1024	sub time { Time::HiRes::time }	1151	sub time { _time }
1025	sub now { Time::HiRes::time }	1152	sub now { _time }
		1153	sub now_update { }
1026		1154
1027	# default implementation for ->condvar	1155	# default implementation for ->condvar
1028		1156
1029	sub condvar {	1157	sub condvar {
1030	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1158	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1031	}	1159	}
1032		1160
1033	# default implementation for ->signal	1161	# default implementation for ->signal
1034		1162
1035	our %SIG_CB;	1163	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1164
		1165	sub _signal_exec {
		1166	sysread $SIGPIPE_R, my $dummy, 4;
		1167
		1168	while (%SIG_EV) {
		1169	for (keys %SIG_EV) {
		1170	delete $SIG_EV{$_};
		1171	$_->() for values %{ $SIG_CB{$_} \|\| {} };
		1172	}
		1173	}
		1174	}
1036		1175
1037	sub signal {	1176	sub signal {
1038	my (undef, %arg) = @_;	1177	my (undef, %arg) = @_;
1039		1178
		1179	unless ($SIGPIPE_R) {
		1180	require Fcntl;
		1181
		1182	if (AnyEvent::WIN32) {
		1183	require AnyEvent::Util;
		1184
		1185	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1186	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1187	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1188	} else {
		1189	pipe $SIGPIPE_R, $SIGPIPE_W;
		1190	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1191	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1192
		1193	# not strictly required, as $^F is normally 2, but let's make sure...
		1194	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1195	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1196	}
		1197
		1198	$SIGPIPE_R
		1199	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1200
		1201	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1202	}
		1203
1040	my $signal = uc $arg{signal}	1204	my $signal = uc $arg{signal}
1041	or Carp::croak "required option 'signal' is missing";	1205	or Carp::croak "required option 'signal' is missing";
1042		1206
1043	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1207	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1044	$SIG{$signal} \|\|= sub {	1208	$SIG{$signal} \|\|= sub {
1045	$_->() for values %{ $SIG_CB{$signal} \|\| {} };	1209	local $!;
		1210	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1211	undef $SIG_EV{$signal};
1046	};	1212	};
1047		1213
1048	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1214	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1049	}	1215	}
1050		1216
1051	sub AnyEvent::Base::Signal::DESTROY {	1217	sub AnyEvent::Base::signal::DESTROY {
1052	my ($signal, $cb) = @{$_[0]};	1218	my ($signal, $cb) = @{$_[0]};
1053		1219
1054	delete $SIG_CB{$signal}{$cb};	1220	delete $SIG_CB{$signal}{$cb};
1055		1221
		1222	# delete doesn't work with older perls - they then
		1223	# print weird messages, or just unconditionally exit
		1224	# instead of getting the default action.
1056	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };	1225	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1057	}	1226	}
1058		1227
1059	# default implementation for ->child	1228	# default implementation for ->child
1060		1229
1061	our %PID_CB;	1230	our %PID_CB;
1062	our $CHLD_W;	1231	our $CHLD_W;
1063	our $CHLD_DELAY_W;	1232	our $CHLD_DELAY_W;
1064	our $PID_IDLE;
1065	our $WNOHANG;	1233	our $WNOHANG;
1066		1234
1067	sub _child_wait {	1235	sub _sigchld {
1068	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1236	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1069	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),	1237	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),
1070	(values %{ $PID_CB{0} \|\| {} });	1238	(values %{ $PID_CB{0} \|\| {} });
1071	}	1239	}
1072
1073	undef $PID_IDLE;
1074	}
1075
1076	sub _sigchld {
1077	# make sure we deliver these changes "synchronous" with the event loop.
1078	$CHLD_DELAY_W \|\|= AnyEvent->timer (after => 0, cb => sub {
1079	undef $CHLD_DELAY_W;
1080	&_child_wait;
1081	});
1082	}	1240	}
1083		1241
1084	sub child {	1242	sub child {
1085	my (undef, %arg) = @_;	1243	my (undef, %arg) = @_;
1086		1244
1087	defined (my $pid = $arg{pid} + 0)	1245	defined (my $pid = $arg{pid} + 0)
1088	or Carp::croak "required option 'pid' is missing";	1246	or Carp::croak "required option 'pid' is missing";
1089		1247
1090	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1248	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1091		1249
1092	unless ($WNOHANG) {
1093	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;	1250	$WNOHANG \|\|= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
1094	}
1095		1251
1096	unless ($CHLD_W) {	1252	unless ($CHLD_W) {
1097	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1253	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1098	# child could be a zombie already, so make at least one round	1254	# child could be a zombie already, so make at least one round
1099	&_sigchld;	1255	&_sigchld;
1100	}	1256	}
1101		1257
1102	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1258	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1103	}	1259	}
1104		1260
1105	sub AnyEvent::Base::Child::DESTROY {	1261	sub AnyEvent::Base::child::DESTROY {
1106	my ($pid, $cb) = @{$_[0]};	1262	my ($pid, $cb) = @{$_[0]};
1107		1263
1108	delete $PID_CB{$pid}{$cb};	1264	delete $PID_CB{$pid}{$cb};
1109	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1265	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1110		1266
1111	undef $CHLD_W unless keys %PID_CB;	1267	undef $CHLD_W unless keys %PID_CB;
		1268	}
		1269
		1270	# idle emulation is done by simply using a timer, regardless
		1271	# of whether the process is idle or not, and not letting
		1272	# the callback use more than 50% of the time.
		1273	sub idle {
		1274	my (undef, %arg) = @_;
		1275
		1276	my ($cb, $w, $rcb) = $arg{cb};
		1277
		1278	$rcb = sub {
		1279	if ($cb) {
		1280	$w = _time;
		1281	&$cb;
		1282	$w = _time - $w;
		1283
		1284	# never use more then 50% of the time for the idle watcher,
		1285	# within some limits
		1286	$w = 0.0001 if $w < 0.0001;
		1287	$w = 5 if $w > 5;
		1288
		1289	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1290	} else {
		1291	# clean up...
		1292	undef $w;
		1293	undef $rcb;
		1294	}
		1295	};
		1296
		1297	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1298
		1299	bless \\$cb, "AnyEvent::Base::idle"
		1300	}
		1301
		1302	sub AnyEvent::Base::idle::DESTROY {
		1303	undef $${$_[0]};
1112	}	1304	}
1113		1305
1114	package AnyEvent::CondVar;	1306	package AnyEvent::CondVar;
1115		1307
1116	our @ISA = AnyEvent::CondVar::Base::;	1308	our @ISA = AnyEvent::CondVar::Base::;
…		…
1168	}	1360	}
1169		1361
1170	# undocumented/compatibility with pre-3.4	1362	# undocumented/compatibility with pre-3.4
1171	*broadcast = \&send;	1363	*broadcast = \&send;
1172	*wait = \&_wait;	1364	*wait = \&_wait;
		1365
		1366	=head1 ERROR AND EXCEPTION HANDLING
		1367
		1368	In general, AnyEvent does not do any error handling - it relies on the
		1369	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1370	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1371	checking of all AnyEvent methods, however, which is highly useful during
		1372	development.
		1373
		1374	As for exception handling (i.e. runtime errors and exceptions thrown while
		1375	executing a callback), this is not only highly event-loop specific, but
		1376	also not in any way wrapped by this module, as this is the job of the main
		1377	program.
		1378
		1379	The pure perl event loop simply re-throws the exception (usually
		1380	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1381	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1382	so on.
		1383
		1384	=head1 ENVIRONMENT VARIABLES
		1385
		1386	The following environment variables are used by this module or its
		1387	submodules.
		1388
		1389	Note that AnyEvent will remove I<all> environment variables starting with
		1390	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1391	enabled.
		1392
		1393	=over 4
		1394
		1395	=item C<PERL_ANYEVENT_VERBOSE>
		1396
		1397	By default, AnyEvent will be completely silent except in fatal
		1398	conditions. You can set this environment variable to make AnyEvent more
		1399	talkative.
		1400
		1401	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1402	conditions, such as not being able to load the event model specified by
		1403	C<PERL_ANYEVENT_MODEL>.
		1404
		1405	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1406	model it chooses.
		1407
		1408	=item C<PERL_ANYEVENT_STRICT>
		1409
		1410	AnyEvent does not do much argument checking by default, as thorough
		1411	argument checking is very costly. Setting this variable to a true value
		1412	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1413	check the arguments passed to most method calls. If it finds any problems,
		1414	it will croak.
		1415
		1416	In other words, enables "strict" mode.
		1417
		1418	Unlike C<use strict>, it is definitely recommended to keep it off in
		1419	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1420	developing programs can be very useful, however.
		1421
		1422	=item C<PERL_ANYEVENT_MODEL>
		1423
		1424	This can be used to specify the event model to be used by AnyEvent, before
		1425	auto detection and -probing kicks in. It must be a string consisting
		1426	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1427	and the resulting module name is loaded and if the load was successful,
		1428	used as event model. If it fails to load AnyEvent will proceed with
		1429	auto detection and -probing.
		1430
		1431	This functionality might change in future versions.
		1432
		1433	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1434	could start your program like this:
		1435
		1436	PERL_ANYEVENT_MODEL=Perl perl ...
		1437
		1438	=item C<PERL_ANYEVENT_PROTOCOLS>
		1439
		1440	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1441	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1442	of auto probing).
		1443
		1444	Must be set to a comma-separated list of protocols or address families,
		1445	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1446	used, and preference will be given to protocols mentioned earlier in the
		1447	list.
		1448
		1449	This variable can effectively be used for denial-of-service attacks
		1450	against local programs (e.g. when setuid), although the impact is likely
		1451	small, as the program has to handle conenction and other failures anyways.
		1452
		1453	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1454	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1455	- only support IPv4, never try to resolve or contact IPv6
		1456	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1457	IPv6, but prefer IPv6 over IPv4.
		1458
		1459	=item C<PERL_ANYEVENT_EDNS0>
		1460
		1461	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1462	for DNS. This extension is generally useful to reduce DNS traffic, but
		1463	some (broken) firewalls drop such DNS packets, which is why it is off by
		1464	default.
		1465
		1466	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1467	EDNS0 in its DNS requests.
		1468
		1469	=item C<PERL_ANYEVENT_MAX_FORKS>
		1470
		1471	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1472	will create in parallel.
		1473
		1474	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1475
		1476	The default value for the C<max_outstanding> parameter for the default DNS
		1477	resolver - this is the maximum number of parallel DNS requests that are
		1478	sent to the DNS server.
		1479
		1480	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1481
		1482	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1483	configuration) in the default resolver. When set to the empty string, no
		1484	default config will be used.
		1485
		1486	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1487
		1488	When neither C<ca_file> nor C<ca_path> was specified during
		1489	L<AnyEvent::TLS> context creation, and either of these environment
		1490	variables exist, they will be used to specify CA certificate locations
		1491	instead of a system-dependent default.
		1492
		1493	=back
1173		1494
1174	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1495	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1175		1496
1176	This is an advanced topic that you do not normally need to use AnyEvent in	1497	This is an advanced topic that you do not normally need to use AnyEvent in
1177	a module. This section is only of use to event loop authors who want to	1498	a module. This section is only of use to event loop authors who want to
…		…
1211		1532
1212	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1533	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1213	condition variables: code blocking while waiting for a condition will	1534	condition variables: code blocking while waiting for a condition will
1214	C<die>. This still works with most modules/usages, and blocking calls must	1535	C<die>. This still works with most modules/usages, and blocking calls must
1215	not be done in an interactive application, so it makes sense.	1536	not be done in an interactive application, so it makes sense.
1216
1217	=head1 ENVIRONMENT VARIABLES
1218
1219	The following environment variables are used by this module:
1220
1221	=over 4
1222
1223	=item C<PERL_ANYEVENT_VERBOSE>
1224
1225	By default, AnyEvent will be completely silent except in fatal
1226	conditions. You can set this environment variable to make AnyEvent more
1227	talkative.
1228
1229	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1230	conditions, such as not being able to load the event model specified by
1231	C<PERL_ANYEVENT_MODEL>.
1232
1233	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1234	model it chooses.
1235
1236	=item C<PERL_ANYEVENT_STRICT>
1237
1238	AnyEvent does not do much argument checking by default, as thorough
1239	argument checking is very costly. Setting this variable to a true value
1240	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1241	check the arguments passed to most method calls. If it finds any problems
1242	it will croak.
1243
1244	In other words, enables "strict" mode.
1245
1246	Unlike C<use strict> it is definitely recommended ot keep it off in
1247	production.
1248
1249	=item C<PERL_ANYEVENT_MODEL>
1250
1251	This can be used to specify the event model to be used by AnyEvent, before
1252	auto detection and -probing kicks in. It must be a string consisting
1253	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1254	and the resulting module name is loaded and if the load was successful,
1255	used as event model. If it fails to load AnyEvent will proceed with
1256	auto detection and -probing.
1257
1258	This functionality might change in future versions.
1259
1260	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1261	could start your program like this:
1262
1263	PERL_ANYEVENT_MODEL=Perl perl ...
1264
1265	=item C<PERL_ANYEVENT_PROTOCOLS>
1266
1267	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1268	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1269	of auto probing).
1270
1271	Must be set to a comma-separated list of protocols or address families,
1272	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1273	used, and preference will be given to protocols mentioned earlier in the
1274	list.
1275
1276	This variable can effectively be used for denial-of-service attacks
1277	against local programs (e.g. when setuid), although the impact is likely
1278	small, as the program has to handle connection errors already-
1279
1280	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1281	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1282	- only support IPv4, never try to resolve or contact IPv6
1283	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1284	IPv6, but prefer IPv6 over IPv4.
1285
1286	=item C<PERL_ANYEVENT_EDNS0>
1287
1288	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1289	for DNS. This extension is generally useful to reduce DNS traffic, but
1290	some (broken) firewalls drop such DNS packets, which is why it is off by
1291	default.
1292
1293	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1294	EDNS0 in its DNS requests.
1295
1296	=item C<PERL_ANYEVENT_MAX_FORKS>
1297
1298	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1299	will create in parallel.
1300
1301	=back
1302		1537
1303	=head1 EXAMPLE PROGRAM	1538	=head1 EXAMPLE PROGRAM
1304		1539
1305	The following program uses an I/O watcher to read data from STDIN, a timer	1540	The following program uses an I/O watcher to read data from STDIN, a timer
1306	to display a message once per second, and a condition variable to quit the	1541	to display a message once per second, and a condition variable to quit the
…		…
1500	watcher.	1735	watcher.
1501		1736
1502	=head3 Results	1737	=head3 Results
1503		1738
1504	name watchers bytes create invoke destroy comment	1739	name watchers bytes create invoke destroy comment
1505	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1740	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1506	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1741	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1507	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1742	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1508	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1743	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1509	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1744	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1510	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	1745	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		1746	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		1747	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1511	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1748	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1512	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1749	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1513	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1750	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1514	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1751	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1515		1752
1516	=head3 Discussion	1753	=head3 Discussion
1517		1754
1518	The benchmark does I<not> measure scalability of the event loop very	1755	The benchmark does I<not> measure scalability of the event loop very
1519	well. For example, a select-based event loop (such as the pure perl one)	1756	well. For example, a select-based event loop (such as the pure perl one)
…		…
1544	performance becomes really bad with lots of file descriptors (and few of	1781	performance becomes really bad with lots of file descriptors (and few of
1545	them active), of course, but this was not subject of this benchmark.	1782	them active), of course, but this was not subject of this benchmark.
1546		1783
1547	The C<Event> module has a relatively high setup and callback invocation	1784	The C<Event> module has a relatively high setup and callback invocation
1548	cost, but overall scores in on the third place.	1785	cost, but overall scores in on the third place.
		1786
		1787	C<IO::Async> performs admirably well, about on par with C<Event>, even
		1788	when using its pure perl backend.
1549		1789
1550	C<Glib>'s memory usage is quite a bit higher, but it features a	1790	C<Glib>'s memory usage is quite a bit higher, but it features a
1551	faster callback invocation and overall ends up in the same class as	1791	faster callback invocation and overall ends up in the same class as
1552	C<Event>. However, Glib scales extremely badly, doubling the number of	1792	C<Event>. However, Glib scales extremely badly, doubling the number of
1553	watchers increases the processing time by more than a factor of four,	1793	watchers increases the processing time by more than a factor of four,
…		…
1631	it to another server. This includes deleting the old timeout and creating	1871	it to another server. This includes deleting the old timeout and creating
1632	a new one that moves the timeout into the future.	1872	a new one that moves the timeout into the future.
1633		1873
1634	=head3 Results	1874	=head3 Results
1635		1875
1636	name sockets create request	1876	name sockets create request
1637	EV 20000 69.01 11.16	1877	EV 20000 69.01 11.16
1638	Perl 20000 73.32 35.87	1878	Perl 20000 73.32 35.87
		1879	IOAsync 20000 157.00 98.14 epoll
		1880	IOAsync 20000 159.31 616.06 poll
1639	Event 20000 212.62 257.32	1881	Event 20000 212.62 257.32
1640	Glib 20000 651.16 1896.30	1882	Glib 20000 651.16 1896.30
1641	POE 20000 349.67 12317.24 uses POE::Loop::Event	1883	POE 20000 349.67 12317.24 uses POE::Loop::Event
1642		1884
1643	=head3 Discussion	1885	=head3 Discussion
1644		1886
1645	This benchmark I<does> measure scalability and overall performance of the	1887	This benchmark I<does> measure scalability and overall performance of the
1646	particular event loop.	1888	particular event loop.
…		…
1648	EV is again fastest. Since it is using epoll on my system, the setup time	1890	EV is again fastest. Since it is using epoll on my system, the setup time
1649	is relatively high, though.	1891	is relatively high, though.
1650		1892
1651	Perl surprisingly comes second. It is much faster than the C-based event	1893	Perl surprisingly comes second. It is much faster than the C-based event
1652	loops Event and Glib.	1894	loops Event and Glib.
		1895
		1896	IO::Async performs very well when using its epoll backend, and still quite
		1897	good compared to Glib when using its pure perl backend.
1653		1898
1654	Event suffers from high setup time as well (look at its code and you will	1899	Event suffers from high setup time as well (look at its code and you will
1655	understand why). Callback invocation also has a high overhead compared to	1900	understand why). Callback invocation also has a high overhead compared to
1656	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	1901	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1657	uses select or poll in basically all documented configurations.	1902	uses select or poll in basically all documented configurations.
…		…
1720	=item * C-based event loops perform very well with small number of	1965	=item * C-based event loops perform very well with small number of
1721	watchers, as the management overhead dominates.	1966	watchers, as the management overhead dominates.
1722		1967
1723	=back	1968	=back
1724		1969
		1970	=head2 THE IO::Lambda BENCHMARK
		1971
		1972	Recently I was told about the benchmark in the IO::Lambda manpage, which
		1973	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		1974	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		1975	shouldn't come as a surprise to anybody). As such, the benchmark is
		1976	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		1977	very optimal. But how would AnyEvent compare when used without the extra
		1978	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		1979
		1980	The benchmark itself creates an echo-server, and then, for 500 times,
		1981	connects to the echo server, sends a line, waits for the reply, and then
		1982	creates the next connection. This is a rather bad benchmark, as it doesn't
		1983	test the efficiency of the framework or much non-blocking I/O, but it is a
		1984	benchmark nevertheless.
		1985
		1986	name runtime
		1987	Lambda/select 0.330 sec
		1988	+ optimized 0.122 sec
		1989	Lambda/AnyEvent 0.327 sec
		1990	+ optimized 0.138 sec
		1991	Raw sockets/select 0.077 sec
		1992	POE/select, components 0.662 sec
		1993	POE/select, raw sockets 0.226 sec
		1994	POE/select, optimized 0.404 sec
		1995
		1996	AnyEvent/select/nb 0.085 sec
		1997	AnyEvent/EV/nb 0.068 sec
		1998	+state machine 0.134 sec
		1999
		2000	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2001	benchmarks actually make blocking connects and use 100% blocking I/O,
		2002	defeating the purpose of an event-based solution. All of the newly
		2003	written AnyEvent benchmarks use 100% non-blocking connects (using
		2004	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2005	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2006	generally require a lot more bookkeeping and event handling than blocking
		2007	connects (which involve a single syscall only).
		2008
		2009	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2010	offers similar expressive power as POE and IO::Lambda, using conventional
		2011	Perl syntax. This means that both the echo server and the client are 100%
		2012	non-blocking, further placing it at a disadvantage.
		2013
		2014	As you can see, the AnyEvent + EV combination even beats the
		2015	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2016	backend easily beats IO::Lambda and POE.
		2017
		2018	And even the 100% non-blocking version written using the high-level (and
		2019	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2020	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2021	in a non-blocking way.
		2022
		2023	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2024	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2025	part of the IO::lambda distribution and were used without any changes.
		2026
		2027
		2028	=head1 SIGNALS
		2029
		2030	AnyEvent currently installs handlers for these signals:
		2031
		2032	=over 4
		2033
		2034	=item SIGCHLD
		2035
		2036	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		2037	emulation for event loops that do not support them natively. Also, some
		2038	event loops install a similar handler.
		2039
		2040	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will
		2041	reset it to default, to avoid losing child exit statuses.
		2042
		2043	=item SIGPIPE
		2044
		2045	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		2046	when AnyEvent gets loaded.
		2047
		2048	The rationale for this is that AnyEvent users usually do not really depend
		2049	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		2050	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		2051	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		2052	some random socket.
		2053
		2054	The rationale for installing a no-op handler as opposed to ignoring it is
		2055	that this way, the handler will be restored to defaults on exec.
		2056
		2057	Feel free to install your own handler, or reset it to defaults.
		2058
		2059	=back
		2060
		2061	=cut
		2062
		2063	undef $SIG{CHLD}
		2064	if $SIG{CHLD} eq 'IGNORE';
		2065
		2066	$SIG{PIPE} = sub { }
		2067	unless defined $SIG{PIPE};
1725		2068
1726	=head1 FORK	2069	=head1 FORK
1727		2070
1728	Most event libraries are not fork-safe. The ones who are usually are	2071	Most event libraries are not fork-safe. The ones who are usually are
1729	because they rely on inefficient but fork-safe C<select> or C<poll>	2072	because they rely on inefficient but fork-safe C<select> or C<poll>
…		…
1750	use AnyEvent;	2093	use AnyEvent;
1751		2094
1752	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2095	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1753	be used to probe what backend is used and gain other information (which is	2096	be used to probe what backend is used and gain other information (which is
1754	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2097	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1755	$ENV{PERL_ANYEGENT_STRICT}.	2098	$ENV{PERL_ANYEVENT_STRICT}.
		2099
		2100	Note that AnyEvent will remove I<all> environment variables starting with
		2101	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2102	enabled.
1756		2103
1757		2104
1758	=head1 BUGS	2105	=head1 BUGS
1759		2106
1760	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2107	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1761	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2108	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1762	and check wether the leaks still show up. (Perl 5.10.0 has other annoying	2109	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1763	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as	2110	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1764	pronounced).	2111	pronounced).
1765		2112
1766		2113
1767	=head1 SEE ALSO	2114	=head1 SEE ALSO
1768		2115

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.173 by root, Mon Jul 21 03:47:22 2008 UTC vs. Revision 1.229 by root, Wed Jul 8 02:01:12 2009 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.173 by root, Mon Jul 21 03:47:22 2008 UTC vs.
Revision 1.229 by root, Wed Jul 8 02:01:12 2009 UTC