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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.159 by root, Fri Jun 6 16:19:19 2008 UTC vs.
Revision 1.189 by root, Mon Nov 3 21:49:25 2008 UTC

…		…
6		6
7	=head1 SYNOPSIS	7	=head1 SYNOPSIS
8		8
9	use AnyEvent;	9	use AnyEvent;
10		10
11	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub {	11	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub { ... });
12	...
13	});
14		12
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	13	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
		14	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
		15
		16	print AnyEvent->now; # prints current event loop time
		17	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
		18
		19	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
		20
		21	my $w = AnyEvent->child (pid => $pid, cb => sub {
		22	my ($pid, $status) = @_;
16	...	23	...
17	});	24	});
18		25
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	26	my $w = AnyEvent->condvar; # stores whether a condition was flagged
20	$w->send; # wake up current and all future recv's	27	$w->send; # wake up current and all future recv's
21	$w->recv; # enters "main loop" till $condvar gets ->send	28	$w->recv; # enters "main loop" till $condvar gets ->send
		29	# use a condvar in callback mode:
		30	$w->cb (sub { $_[0]->recv });
22		31
23	=head1 INTRODUCTION/TUTORIAL	32	=head1 INTRODUCTION/TUTORIAL
24		33
25	This manpage is mainly a reference manual. If you are interested	34	This manpage is mainly a reference manual. If you are interested
26	in a tutorial or some gentle introduction, have a look at the	35	in a tutorial or some gentle introduction, have a look at the
…		…
33		42
34	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of	43	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
35	policy> and AnyEvent is I<small and efficient>.	44	policy> and AnyEvent is I<small and efficient>.
36		45
37	First and foremost, I<AnyEvent is not an event model> itself, it only	46	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	47	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,	48	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,	49	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	50	only one event loop can be active at the same time in a process. AnyEvent
42	helps hiding the differences between those event loops.	51	cannot change this, but it can hide the differences between those event
		52	loops.
43		53
44	The goal of AnyEvent is to offer module authors the ability to do event	54	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	55	programming (waiting for I/O or timer events) without subscribing to a
46	religion, a way of living, and most importantly: without forcing your	56	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	57	module users into the same thing by forcing them to use the same event
48	model you use.	58	model you use.
49		59
50	For modules like POE or IO::Async (which is a total misnomer as it is	60	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	61	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	62	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	63	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	64	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.	65	module are I<also> forced to use the same event loop you use.
56		66
57	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	67	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
58	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	68	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	69	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,	70	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	71	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	72	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	73	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).	74	to AnyEvent, too, so it is future-proof).
65		75
66	In addition to being free of having to use I<the one and only true event	76	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	77	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	78	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	79	follow. AnyEvent, on the other hand, is lean and up to the point, by only
…		…
152	=head2 I/O WATCHERS	162	=head2 I/O WATCHERS
153		163
154	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	164	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
155	with the following mandatory key-value pairs as arguments:	165	with the following mandatory key-value pairs as arguments:
156		166
157	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	167	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events
158	for events. C<poll> must be a string that is either C<r> or C<w>,	168	(AnyEvent might or might not keep a reference to this file handle). C<poll>
159	which creates a watcher waiting for "r"eadable or "w"ritable events,	169	must be a string that is either C<r> or C<w>, which creates a watcher
160	respectively. C<cb> is the callback to invoke each time the file handle	170	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the
161	becomes ready.	171	callback to invoke each time the file handle becomes ready.
162		172
163	Although the callback might get passed parameters, their value and	173	Although the callback might get passed parameters, their value and
164	presence is undefined and you cannot rely on them. Portable AnyEvent	174	presence is undefined and you cannot rely on them. Portable AnyEvent
165	callbacks cannot use arguments passed to I/O watcher callbacks.	175	callbacks cannot use arguments passed to I/O watcher callbacks.
166		176
…		…
170		180
171	Some event loops issue spurious readyness notifications, so you should	181	Some event loops issue spurious readyness notifications, so you should
172	always use non-blocking calls when reading/writing from/to your file	182	always use non-blocking calls when reading/writing from/to your file
173	handles.	183	handles.
174		184
175	Example:
176
177	# wait for readability of STDIN, then read a line and disable the watcher	185	Example: wait for readability of STDIN, then read a line and disable the
		186	watcher.
		187
178	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	188	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
179	chomp (my $input = <STDIN>);	189	chomp (my $input = <STDIN>);
180	warn "read: $input\n";	190	warn "read: $input\n";
181	undef $w;	191	undef $w;
182	});	192	});
…		…
192		202
193	Although the callback might get passed parameters, their value and	203	Although the callback might get passed parameters, their value and
194	presence is undefined and you cannot rely on them. Portable AnyEvent	204	presence is undefined and you cannot rely on them. Portable AnyEvent
195	callbacks cannot use arguments passed to time watcher callbacks.	205	callbacks cannot use arguments passed to time watcher callbacks.
196		206
197	The timer callback will be invoked at most once: if you want a repeating	207	The callback will normally be invoked once only. If you specify another
198	timer you have to create a new watcher (this is a limitation by both Tk	208	parameter, C<interval>, as a strictly positive number (> 0), then the
199	and Glib).	209	callback will be invoked regularly at that interval (in fractional
		210	seconds) after the first invocation. If C<interval> is specified with a
		211	false value, then it is treated as if it were missing.
200		212
201	Example:	213	The callback will be rescheduled before invoking the callback, but no
		214	attempt is done to avoid timer drift in most backends, so the interval is
		215	only approximate.
202		216
203	# fire an event after 7.7 seconds	217	Example: fire an event after 7.7 seconds.
		218
204	my $w = AnyEvent->timer (after => 7.7, cb => sub {	219	my $w = AnyEvent->timer (after => 7.7, cb => sub {
205	warn "timeout\n";	220	warn "timeout\n";
206	});	221	});
207		222
208	# to cancel the timer:	223	# to cancel the timer:
209	undef $w;	224	undef $w;
210		225
211	Example 2:
212
213	# fire an event after 0.5 seconds, then roughly every second	226	Example 2: fire an event after 0.5 seconds, then roughly every second.
214	my $w;
215		227
216	my $cb = sub {
217	# cancel the old timer while creating a new one
218	$w = AnyEvent->timer (after => 1, cb => $cb);	228	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		229	warn "timeout\n";
219	};	230	};
220
221	# start the "loop" by creating the first watcher
222	$w = AnyEvent->timer (after => 0.5, cb => $cb);
223		231
224	=head3 TIMING ISSUES	232	=head3 TIMING ISSUES
225		233
226	There are two ways to handle timers: based on real time (relative, "fire	234	There are two ways to handle timers: based on real time (relative, "fire
227	in 10 seconds") and based on wallclock time (absolute, "fire at 12	235	in 10 seconds") and based on wallclock time (absolute, "fire at 12
…		…
305	=back	313	=back
306		314
307	=head2 SIGNAL WATCHERS	315	=head2 SIGNAL WATCHERS
308		316
309	You can watch for signals using a signal watcher, C<signal> is the signal	317	You can watch for signals using a signal watcher, C<signal> is the signal
310	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to	318	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
311	be invoked whenever a signal occurs.	319	callback to be invoked whenever a signal occurs.
312		320
313	Although the callback might get passed parameters, their value and	321	Although the callback might get passed parameters, their value and
314	presence is undefined and you cannot rely on them. Portable AnyEvent	322	presence is undefined and you cannot rely on them. Portable AnyEvent
315	callbacks cannot use arguments passed to signal watcher callbacks.	323	callbacks cannot use arguments passed to signal watcher callbacks.
316		324
…		…
332	=head2 CHILD PROCESS WATCHERS	340	=head2 CHILD PROCESS WATCHERS
333		341
334	You can also watch on a child process exit and catch its exit status.	342	You can also watch on a child process exit and catch its exit status.
335		343
336	The child process is specified by the C<pid> argument (if set to C<0>, it	344	The child process is specified by the C<pid> argument (if set to C<0>, it
337	watches for any child process exit). The watcher will trigger as often	345	watches for any child process exit). The watcher will triggered only when
338	as status change for the child are received. This works by installing a	346	the child process has finished and an exit status is available, not on
339	signal handler for C<SIGCHLD>. The callback will be called with the pid	347	any trace events (stopped/continued).
340	and exit status (as returned by waitpid), so unlike other watcher types,	348
341	you I<can> rely on child watcher callback arguments.	349	The callback will be called with the pid and exit status (as returned by
		350	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		351	callback arguments.
		352
		353	This watcher type works by installing a signal handler for C<SIGCHLD>,
		354	and since it cannot be shared, nothing else should use SIGCHLD or reap
		355	random child processes (waiting for specific child processes, e.g. inside
		356	C<system>, is just fine).
342		357
343	There is a slight catch to child watchers, however: you usually start them	358	There is a slight catch to child watchers, however: you usually start them
344	I<after> the child process was created, and this means the process could	359	I<after> the child process was created, and this means the process could
345	have exited already (and no SIGCHLD will be sent anymore).	360	have exited already (and no SIGCHLD will be sent anymore).
346		361
…		…
382	The instrument to do that is called a "condition variable", so called	397	The instrument to do that is called a "condition variable", so called
383	because they represent a condition that must become true.	398	because they represent a condition that must become true.
384		399
385	Condition variables can be created by calling the C<< AnyEvent->condvar	400	Condition variables can be created by calling the C<< AnyEvent->condvar
386	>> method, usually without arguments. The only argument pair allowed is	401	>> method, usually without arguments. The only argument pair allowed is
		402
387	C<cb>, which specifies a callback to be called when the condition variable	403	C<cb>, which specifies a callback to be called when the condition variable
388	becomes true.	404	becomes true, with the condition variable as the first argument (but not
		405	the results).
389		406
390	After creation, the condition variable is "false" until it becomes "true"	407	After creation, the condition variable is "false" until it becomes "true"
391	by calling the C<send> method (or calling the condition variable as if it	408	by calling the C<send> method (or calling the condition variable as if it
392	were a callback, read about the caveats in the description for the C<<	409	were a callback, read about the caveats in the description for the C<<
393	->send >> method).	410	->send >> method).
…		…
449		466
450	my $done = AnyEvent->condvar;	467	my $done = AnyEvent->condvar;
451	my $delay = AnyEvent->timer (after => 5, cb => $done);	468	my $delay = AnyEvent->timer (after => 5, cb => $done);
452	$done->recv;	469	$done->recv;
453		470
		471	Example: Imagine an API that returns a condvar and doesn't support
		472	callbacks. This is how you make a synchronous call, for example from
		473	the main program:
		474
		475	use AnyEvent::CouchDB;
		476
		477	...
		478
		479	my @info = $couchdb->info->recv;
		480
		481	And this is how you would just ste a callback to be called whenever the
		482	results are available:
		483
		484	$couchdb->info->cb (sub {
		485	my @info = $_[0]->recv;
		486	});
		487
454	=head3 METHODS FOR PRODUCERS	488	=head3 METHODS FOR PRODUCERS
455		489
456	These methods should only be used by the producing side, i.e. the	490	These methods should only be used by the producing side, i.e. the
457	code/module that eventually sends the signal. Note that it is also	491	code/module that eventually sends the signal. Note that it is also
458	the producer side which creates the condvar in most cases, but it isn't	492	the producer side which creates the condvar in most cases, but it isn't
…		…
591	=item $bool = $cv->ready	625	=item $bool = $cv->ready
592		626
593	Returns true when the condition is "true", i.e. whether C<send> or	627	Returns true when the condition is "true", i.e. whether C<send> or
594	C<croak> have been called.	628	C<croak> have been called.
595		629
596	=item $cb = $cv->cb ([new callback])	630	=item $cb = $cv->cb ($cb->($cv))
597		631
598	This is a mutator function that returns the callback set and optionally	632	This is a mutator function that returns the callback set and optionally
599	replaces it before doing so.	633	replaces it before doing so.
600		634
601	The callback will be called when the condition becomes "true", i.e. when	635	The callback will be called when the condition becomes "true", i.e. when
…		…
738	=item L<AnyEvent::Util>	772	=item L<AnyEvent::Util>
739		773
740	Contains various utility functions that replace often-used but blocking	774	Contains various utility functions that replace often-used but blocking
741	functions such as C<inet_aton> by event-/callback-based versions.	775	functions such as C<inet_aton> by event-/callback-based versions.
742		776
743	=item L<AnyEvent::Handle>
744
745	Provide read and write buffers and manages watchers for reads and writes.
746
747	=item L<AnyEvent::Socket>	777	=item L<AnyEvent::Socket>
748		778
749	Provides various utility functions for (internet protocol) sockets,	779	Provides various utility functions for (internet protocol) sockets,
750	addresses and name resolution. Also functions to create non-blocking tcp	780	addresses and name resolution. Also functions to create non-blocking tcp
751	connections or tcp servers, with IPv6 and SRV record support and more.	781	connections or tcp servers, with IPv6 and SRV record support and more.
752		782
		783	=item L<AnyEvent::Handle>
		784
		785	Provide read and write buffers, manages watchers for reads and writes,
		786	supports raw and formatted I/O, I/O queued and fully transparent and
		787	non-blocking SSL/TLS.
		788
753	=item L<AnyEvent::DNS>	789	=item L<AnyEvent::DNS>
754		790
755	Provides rich asynchronous DNS resolver capabilities.	791	Provides rich asynchronous DNS resolver capabilities.
756		792
757	=item L<AnyEvent::HTTP>	793	=item L<AnyEvent::HTTP>
…		…
767		803
768	The fastest ping in the west.	804	The fastest ping in the west.
769		805
770	=item L<AnyEvent::DBI>	806	=item L<AnyEvent::DBI>
771		807
772	Executes DBI requests asynchronously in a proxy process.	808	Executes L<DBI> requests asynchronously in a proxy process.
773		809
		810	=item L<AnyEvent::AIO>
		811
		812	Truly asynchronous I/O, should be in the toolbox of every event
		813	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		814	together.
		815
		816	=item L<AnyEvent::BDB>
		817
		818	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		819	L<BDB> and AnyEvent together.
		820
		821	=item L<AnyEvent::GPSD>
		822
		823	A non-blocking interface to gpsd, a daemon delivering GPS information.
		824
		825	=item L<AnyEvent::IGS>
		826
		827	A non-blocking interface to the Internet Go Server protocol (used by
		828	L<App::IGS>).
		829
774	=item L<Net::IRC3>	830	=item L<AnyEvent::IRC>
775		831
776	AnyEvent based IRC client module family.	832	AnyEvent based IRC client module family (replacing the older Net::IRC3).
777		833
778	=item L<Net::XMPP2>	834	=item L<Net::XMPP2>
779		835
780	AnyEvent based XMPP (Jabber protocol) module family.	836	AnyEvent based XMPP (Jabber protocol) module family.
781		837
…		…
790		846
791	=item L<Coro>	847	=item L<Coro>
792		848
793	Has special support for AnyEvent via L<Coro::AnyEvent>.	849	Has special support for AnyEvent via L<Coro::AnyEvent>.
794		850
795	=item L<AnyEvent::AIO>, L<IO::AIO>
796
797	Truly asynchronous I/O, should be in the toolbox of every event
798	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
799	together.
800
801	=item L<AnyEvent::BDB>, L<BDB>
802
803	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
804	IO::AIO and AnyEvent together.
805
806	=item L<IO::Lambda>	851	=item L<IO::Lambda>
807		852
808	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	853	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
809		854
810	=back	855	=back
…		…
812	=cut	857	=cut
813		858
814	package AnyEvent;	859	package AnyEvent;
815		860
816	no warnings;	861	no warnings;
817	use strict;	862	use strict qw(vars subs);
818		863
819	use Carp;	864	use Carp;
820		865
821	our $VERSION = 4.151;	866	our $VERSION = 4.32;
822	our $MODEL;	867	our $MODEL;
823		868
824	our $AUTOLOAD;	869	our $AUTOLOAD;
825	our @ISA;	870	our @ISA;
826		871
…		…
929	$MODEL	974	$MODEL
930	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	975	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
931	}	976	}
932	}	977	}
933		978
		979	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		980
934	unshift @ISA, $MODEL;	981	unshift @ISA, $MODEL;
935	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	982
		983	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
936		984
937	(shift @post_detect)->() while @post_detect;	985	(shift @post_detect)->() while @post_detect;
938	}	986	}
939		987
940	$MODEL	988	$MODEL
…		…
950		998
951	my $class = shift;	999	my $class = shift;
952	$class->$func (@_);	1000	$class->$func (@_);
953	}	1001	}
954		1002
		1003	# utility function to dup a filehandle. this is used by many backends
		1004	# to support binding more than one watcher per filehandle (they usually
		1005	# allow only one watcher per fd, so we dup it to get a different one).
		1006	sub _dupfh($$$$) {
		1007	my ($poll, $fh, $r, $w) = @_;
		1008
		1009	require Fcntl;
		1010
		1011	# cygwin requires the fh mode to be matching, unix doesn't
		1012	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		1013	: $poll eq "w" ? ($w, ">")
		1014	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		1015
		1016	open my $fh2, "$mode&" . fileno $fh
		1017	or die "cannot dup() filehandle: $!";
		1018
		1019	# we assume CLOEXEC is already set by perl in all important cases
		1020
		1021	($fh2, $rw)
		1022	}
		1023
955	package AnyEvent::Base;	1024	package AnyEvent::Base;
956		1025
957	# default implementation for now and time	1026	# default implementation for now and time
958		1027
959	use Time::HiRes ();	1028	BEGIN {
		1029	if (eval "use Time::HiRes (); time (); 1") {
		1030	*_time = \&Time::HiRes::time;
		1031	# if (eval "use POSIX (); (POSIX::times())...
		1032	} else {
		1033	*_time = sub { time }; # epic fail
		1034	}
		1035	}
960		1036
961	sub time { Time::HiRes::time }	1037	sub time { _time }
962	sub now { Time::HiRes::time }	1038	sub now { _time }
963		1039
964	# default implementation for ->condvar	1040	# default implementation for ->condvar
965		1041
966	sub condvar {	1042	sub condvar {
967	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1043	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
…		…
988	sub AnyEvent::Base::Signal::DESTROY {	1064	sub AnyEvent::Base::Signal::DESTROY {
989	my ($signal, $cb) = @{$_[0]};	1065	my ($signal, $cb) = @{$_[0]};
990		1066
991	delete $SIG_CB{$signal}{$cb};	1067	delete $SIG_CB{$signal}{$cb};
992		1068
993	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1069	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
994	}	1070	}
995		1071
996	# default implementation for ->child	1072	# default implementation for ->child
997		1073
998	our %PID_CB;	1074	our %PID_CB;
…		…
1106		1182
1107	# undocumented/compatibility with pre-3.4	1183	# undocumented/compatibility with pre-3.4
1108	*broadcast = \&send;	1184	*broadcast = \&send;
1109	*wait = \&_wait;	1185	*wait = \&_wait;
1110		1186
		1187	=head1 ERROR AND EXCEPTION HANDLING
		1188
		1189	In general, AnyEvent does not do any error handling - it relies on the
		1190	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1191	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1192	checking of all AnyEvent methods, however, which is highly useful during
		1193	development.
		1194
		1195	As for exception handling (i.e. runtime errors and exceptions thrown while
		1196	executing a callback), this is not only highly event-loop specific, but
		1197	also not in any way wrapped by this module, as this is the job of the main
		1198	program.
		1199
		1200	The pure perl event loop simply re-throws the exception (usually
		1201	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1202	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1203	so on.
		1204
		1205	=head1 ENVIRONMENT VARIABLES
		1206
		1207	The following environment variables are used by this module or its
		1208	submodules:
		1209
		1210	=over 4
		1211
		1212	=item C<PERL_ANYEVENT_VERBOSE>
		1213
		1214	By default, AnyEvent will be completely silent except in fatal
		1215	conditions. You can set this environment variable to make AnyEvent more
		1216	talkative.
		1217
		1218	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1219	conditions, such as not being able to load the event model specified by
		1220	C<PERL_ANYEVENT_MODEL>.
		1221
		1222	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1223	model it chooses.
		1224
		1225	=item C<PERL_ANYEVENT_STRICT>
		1226
		1227	AnyEvent does not do much argument checking by default, as thorough
		1228	argument checking is very costly. Setting this variable to a true value
		1229	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1230	check the arguments passed to most method calls. If it finds any problems
		1231	it will croak.
		1232
		1233	In other words, enables "strict" mode.
		1234
		1235	Unlike C<use strict>, it is definitely recommended ot keep it off in
		1236	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1237	developing programs can be very useful, however.
		1238
		1239	=item C<PERL_ANYEVENT_MODEL>
		1240
		1241	This can be used to specify the event model to be used by AnyEvent, before
		1242	auto detection and -probing kicks in. It must be a string consisting
		1243	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1244	and the resulting module name is loaded and if the load was successful,
		1245	used as event model. If it fails to load AnyEvent will proceed with
		1246	auto detection and -probing.
		1247
		1248	This functionality might change in future versions.
		1249
		1250	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1251	could start your program like this:
		1252
		1253	PERL_ANYEVENT_MODEL=Perl perl ...
		1254
		1255	=item C<PERL_ANYEVENT_PROTOCOLS>
		1256
		1257	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1258	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1259	of auto probing).
		1260
		1261	Must be set to a comma-separated list of protocols or address families,
		1262	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1263	used, and preference will be given to protocols mentioned earlier in the
		1264	list.
		1265
		1266	This variable can effectively be used for denial-of-service attacks
		1267	against local programs (e.g. when setuid), although the impact is likely
		1268	small, as the program has to handle connection errors already-
		1269
		1270	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1271	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1272	- only support IPv4, never try to resolve or contact IPv6
		1273	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1274	IPv6, but prefer IPv6 over IPv4.
		1275
		1276	=item C<PERL_ANYEVENT_EDNS0>
		1277
		1278	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1279	for DNS. This extension is generally useful to reduce DNS traffic, but
		1280	some (broken) firewalls drop such DNS packets, which is why it is off by
		1281	default.
		1282
		1283	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1284	EDNS0 in its DNS requests.
		1285
		1286	=item C<PERL_ANYEVENT_MAX_FORKS>
		1287
		1288	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1289	will create in parallel.
		1290
		1291	=back
		1292
1111	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1293	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1112		1294
1113	This is an advanced topic that you do not normally need to use AnyEvent in	1295	This is an advanced topic that you do not normally need to use AnyEvent in
1114	a module. This section is only of use to event loop authors who want to	1296	a module. This section is only of use to event loop authors who want to
1115	provide AnyEvent compatibility.	1297	provide AnyEvent compatibility.
…		…
1148		1330
1149	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1331	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1150	condition variables: code blocking while waiting for a condition will	1332	condition variables: code blocking while waiting for a condition will
1151	C<die>. This still works with most modules/usages, and blocking calls must	1333	C<die>. This still works with most modules/usages, and blocking calls must
1152	not be done in an interactive application, so it makes sense.	1334	not be done in an interactive application, so it makes sense.
1153
1154	=head1 ENVIRONMENT VARIABLES
1155
1156	The following environment variables are used by this module:
1157
1158	=over 4
1159
1160	=item C<PERL_ANYEVENT_VERBOSE>
1161
1162	By default, AnyEvent will be completely silent except in fatal
1163	conditions. You can set this environment variable to make AnyEvent more
1164	talkative.
1165
1166	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1167	conditions, such as not being able to load the event model specified by
1168	C<PERL_ANYEVENT_MODEL>.
1169
1170	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1171	model it chooses.
1172
1173	=item C<PERL_ANYEVENT_MODEL>
1174
1175	This can be used to specify the event model to be used by AnyEvent, before
1176	auto detection and -probing kicks in. It must be a string consisting
1177	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1178	and the resulting module name is loaded and if the load was successful,
1179	used as event model. If it fails to load AnyEvent will proceed with
1180	auto detection and -probing.
1181
1182	This functionality might change in future versions.
1183
1184	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1185	could start your program like this:
1186
1187	PERL_ANYEVENT_MODEL=Perl perl ...
1188
1189	=item C<PERL_ANYEVENT_PROTOCOLS>
1190
1191	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1192	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1193	of auto probing).
1194
1195	Must be set to a comma-separated list of protocols or address families,
1196	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1197	used, and preference will be given to protocols mentioned earlier in the
1198	list.
1199
1200	This variable can effectively be used for denial-of-service attacks
1201	against local programs (e.g. when setuid), although the impact is likely
1202	small, as the program has to handle connection errors already-
1203
1204	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1205	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1206	- only support IPv4, never try to resolve or contact IPv6
1207	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1208	IPv6, but prefer IPv6 over IPv4.
1209
1210	=item C<PERL_ANYEVENT_EDNS0>
1211
1212	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1213	for DNS. This extension is generally useful to reduce DNS traffic, but
1214	some (broken) firewalls drop such DNS packets, which is why it is off by
1215	default.
1216
1217	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1218	EDNS0 in its DNS requests.
1219
1220	=item C<PERL_ANYEVENT_MAX_FORKS>
1221
1222	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1223	will create in parallel.
1224
1225	=back
1226		1335
1227	=head1 EXAMPLE PROGRAM	1336	=head1 EXAMPLE PROGRAM
1228		1337
1229	The following program uses an I/O watcher to read data from STDIN, a timer	1338	The following program uses an I/O watcher to read data from STDIN, a timer
1230	to display a message once per second, and a condition variable to quit the	1339	to display a message once per second, and a condition variable to quit the
…		…
1424	watcher.	1533	watcher.
1425		1534
1426	=head3 Results	1535	=head3 Results
1427		1536
1428	name watchers bytes create invoke destroy comment	1537	name watchers bytes create invoke destroy comment
1429	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1538	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1430	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1539	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1431	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1540	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1432	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1541	Perl/Any 100000 452 4.14 0.75 0.99 pure perl implementation
1433	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1542	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1434	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	1543	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1435	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1544	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1436	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1545	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1437	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1546	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1438	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1547	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1439		1548
1440	=head3 Discussion	1549	=head3 Discussion
1441		1550
1442	The benchmark does I<not> measure scalability of the event loop very	1551	The benchmark does I<not> measure scalability of the event loop very
1443	well. For example, a select-based event loop (such as the pure perl one)	1552	well. For example, a select-based event loop (such as the pure perl one)
…		…
1645	watchers, as the management overhead dominates.	1754	watchers, as the management overhead dominates.
1646		1755
1647	=back	1756	=back
1648		1757
1649		1758
		1759	=head1 SIGNALS
		1760
		1761	AnyEvent currently installs handlers for these signals:
		1762
		1763	=over 4
		1764
		1765	=item SIGCHLD
		1766
		1767	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		1768	emulation for event loops that do not support them natively. Also, some
		1769	event loops install a similar handler.
		1770
		1771	=item SIGPIPE
		1772
		1773	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		1774	when AnyEvent gets loaded.
		1775
		1776	The rationale for this is that AnyEvent users usually do not really depend
		1777	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		1778	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		1779	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		1780	some random socket.
		1781
		1782	The rationale for installing a no-op handler as opposed to ignoring it is
		1783	that this way, the handler will be restored to defaults on exec.
		1784
		1785	Feel free to install your own handler, or reset it to defaults.
		1786
		1787	=back
		1788
		1789	=cut
		1790
		1791	$SIG{PIPE} = sub { }
		1792	unless defined $SIG{PIPE};
		1793
		1794
1650	=head1 FORK	1795	=head1 FORK
1651		1796
1652	Most event libraries are not fork-safe. The ones who are usually are	1797	Most event libraries are not fork-safe. The ones who are usually are
1653	because they rely on inefficient but fork-safe C<select> or C<poll>	1798	because they rely on inefficient but fork-safe C<select> or C<poll>
1654	calls. Only L<EV> is fully fork-aware.	1799	calls. Only L<EV> is fully fork-aware.
…		…
1673		1818
1674	use AnyEvent;	1819	use AnyEvent;
1675		1820
1676	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1821	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1677	be used to probe what backend is used and gain other information (which is	1822	be used to probe what backend is used and gain other information (which is
1678	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	1823	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1824	$ENV{PERL_ANYEGENT_STRICT}.
1679		1825
1680		1826
1681	=head1 BUGS	1827	=head1 BUGS
1682		1828
1683	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	1829	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.159 by root, Fri Jun 6 16:19:19 2008 UTC vs. Revision 1.189 by root, Mon Nov 3 21:49:25 2008 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.159 by root, Fri Jun 6 16:19:19 2008 UTC vs.
Revision 1.189 by root, Mon Nov 3 21:49:25 2008 UTC