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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.148 by root, Sat May 31 00:40:16 2008 UTC vs.
Revision 1.210 by root, Wed May 13 15:19:43 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, POE - various supported event loops
6		6
7	=head1 SYNOPSIS	7	=head1 SYNOPSIS
8		8
9	use AnyEvent;	9	use AnyEvent;
10		10
		11	# file descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub {	12	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
		13
		14	# one-shot or repeating timers
		15	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
		16	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
		17
		18	print AnyEvent->now; # prints current event loop time
		19	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
		20
		21	# POSIX signal
		22	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
		23
		24	# child process exit
		25	my $w = AnyEvent->child (pid => $pid, cb => sub {
		26	my ($pid, $status) = @_;
12	...	27	...
13	});	28	});
14		29
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	30	# called when event loop idle (if applicable)
16	...	31	my $w = AnyEvent->idle (cb => sub { ... });
17	});
18		32
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	33	my $w = AnyEvent->condvar; # stores whether a condition was flagged
20	$w->send; # wake up current and all future recv's	34	$w->send; # wake up current and all future recv's
21	$w->recv; # enters "main loop" till $condvar gets ->send	35	$w->recv; # enters "main loop" till $condvar gets ->send
		36	# use a condvar in callback mode:
		37	$w->cb (sub { $_[0]->recv });
22		38
23	=head1 INTRODUCTION/TUTORIAL	39	=head1 INTRODUCTION/TUTORIAL
24		40
25	This manpage is mainly a reference manual. If you are interested	41	This manpage is mainly a reference manual. If you are interested
26	in a tutorial or some gentle introduction, have a look at the	42	in a tutorial or some gentle introduction, have a look at the
33		49
34	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of	50	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
35	policy> and AnyEvent is I<small and efficient>.	51	policy> and AnyEvent is I<small and efficient>.
36		52
37	First and foremost, I<AnyEvent is not an event model> itself, it only	53	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	54	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,	55	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,	56	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	57	only one event loop can be active at the same time in a process. AnyEvent
42	helps hiding the differences between those event loops.	58	cannot change this, but it can hide the differences between those event
		59	loops.
43		60
44	The goal of AnyEvent is to offer module authors the ability to do event	61	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	62	programming (waiting for I/O or timer events) without subscribing to a
46	religion, a way of living, and most importantly: without forcing your	63	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	64	module users into the same thing by forcing them to use the same event
48	model you use.	65	model you use.
49		66
50	For modules like POE or IO::Async (which is a total misnomer as it is	67	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	68	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	69	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	70	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	71	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.	72	module are I<also> forced to use the same event loop you use.
56		73
57	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	74	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
58	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	75	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	76	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,	77	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	78	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	79	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	80	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).	81	to AnyEvent, too, so it is future-proof).
65		82
66	In addition to being free of having to use I<the one and only true event	83	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	84	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	85	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	86	follow. AnyEvent, on the other hand, is lean and up to the point, by only
…		…
127	These watchers are normal Perl objects with normal Perl lifetime. After	144	These watchers are normal Perl objects with normal Perl lifetime. After
128	creating a watcher it will immediately "watch" for events and invoke the	145	creating a watcher it will immediately "watch" for events and invoke the
129	callback when the event occurs (of course, only when the event model	146	callback when the event occurs (of course, only when the event model
130	is in control).	147	is in control).
131		148
		149	Note that B<callbacks must not permanently change global variables>
		150	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
		151	callbacks must not C<die> >>. The former is good programming practise in
		152	Perl and the latter stems from the fact that exception handling differs
		153	widely between event loops.
		154
132	To disable the watcher you have to destroy it (e.g. by setting the	155	To disable the watcher you have to destroy it (e.g. by setting the
133	variable you store it in to C<undef> or otherwise deleting all references	156	variable you store it in to C<undef> or otherwise deleting all references
134	to it).	157	to it).
135		158
136	All watchers are created by calling a method on the C<AnyEvent> class.	159	All watchers are created by calling a method on the C<AnyEvent> class.
…		…
138	Many watchers either are used with "recursion" (repeating timers for	161	Many watchers either are used with "recursion" (repeating timers for
139	example), or need to refer to their watcher object in other ways.	162	example), or need to refer to their watcher object in other ways.
140		163
141	An any way to achieve that is this pattern:	164	An any way to achieve that is this pattern:
142		165
143	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	166	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
144	# you can use $w here, for example to undef it	167	# you can use $w here, for example to undef it
145	undef $w;	168	undef $w;
146	});	169	});
147		170
148	Note that C<my $w; $w => combination. This is necessary because in Perl,	171	Note that C<my $w; $w => combination. This is necessary because in Perl,
149	my variables are only visible after the statement in which they are	172	my variables are only visible after the statement in which they are
150	declared.	173	declared.
151		174
152	=head2 I/O WATCHERS	175	=head2 I/O WATCHERS
153		176
154	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	177	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
155	with the following mandatory key-value pairs as arguments:	178	with the following mandatory key-value pairs as arguments:
156		179
157	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	180	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch
		181	for events (AnyEvent might or might not keep a reference to this file
		182	handle). Note that only file handles pointing to things for which
		183	non-blocking operation makes sense are allowed. This includes sockets,
		184	most character devices, pipes, fifos and so on, but not for example files
		185	or block devices.
		186
158	for events. C<poll> must be a string that is either C<r> or C<w>,	187	C<poll> must be a string that is either C<r> or C<w>, which creates a
159	which creates a watcher waiting for "r"eadable or "w"ritable events,	188	watcher waiting for "r"eadable or "w"ritable events, respectively.
		189
160	respectively. C<cb> is the callback to invoke each time the file handle	190	C<cb> is the callback to invoke each time the file handle becomes ready.
161	becomes ready.
162		191
163	Although the callback might get passed parameters, their value and	192	Although the callback might get passed parameters, their value and
164	presence is undefined and you cannot rely on them. Portable AnyEvent	193	presence is undefined and you cannot rely on them. Portable AnyEvent
165	callbacks cannot use arguments passed to I/O watcher callbacks.	194	callbacks cannot use arguments passed to I/O watcher callbacks.
166		195
…		…
170		199
171	Some event loops issue spurious readyness notifications, so you should	200	Some event loops issue spurious readyness notifications, so you should
172	always use non-blocking calls when reading/writing from/to your file	201	always use non-blocking calls when reading/writing from/to your file
173	handles.	202	handles.
174		203
175	Example:
176
177	# wait for readability of STDIN, then read a line and disable the watcher	204	Example: wait for readability of STDIN, then read a line and disable the
		205	watcher.
		206
178	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	207	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
179	chomp (my $input = <STDIN>);	208	chomp (my $input = <STDIN>);
180	warn "read: $input\n";	209	warn "read: $input\n";
181	undef $w;	210	undef $w;
182	});	211	});
…		…
192		221
193	Although the callback might get passed parameters, their value and	222	Although the callback might get passed parameters, their value and
194	presence is undefined and you cannot rely on them. Portable AnyEvent	223	presence is undefined and you cannot rely on them. Portable AnyEvent
195	callbacks cannot use arguments passed to time watcher callbacks.	224	callbacks cannot use arguments passed to time watcher callbacks.
196		225
197	The timer callback will be invoked at most once: if you want a repeating	226	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	227	parameter, C<interval>, as a strictly positive number (> 0), then the
199	and Glib).	228	callback will be invoked regularly at that interval (in fractional
		229	seconds) after the first invocation. If C<interval> is specified with a
		230	false value, then it is treated as if it were missing.
200		231
201	Example:	232	The callback will be rescheduled before invoking the callback, but no
		233	attempt is done to avoid timer drift in most backends, so the interval is
		234	only approximate.
202		235
203	# fire an event after 7.7 seconds	236	Example: fire an event after 7.7 seconds.
		237
204	my $w = AnyEvent->timer (after => 7.7, cb => sub {	238	my $w = AnyEvent->timer (after => 7.7, cb => sub {
205	warn "timeout\n";	239	warn "timeout\n";
206	});	240	});
207		241
208	# to cancel the timer:	242	# to cancel the timer:
209	undef $w;	243	undef $w;
210		244
211	Example 2:
212
213	# fire an event after 0.5 seconds, then roughly every second	245	Example 2: fire an event after 0.5 seconds, then roughly every second.
214	my $w;
215		246
216	my $cb = sub {
217	# cancel the old timer while creating a new one
218	$w = AnyEvent->timer (after => 1, cb => $cb);	247	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		248	warn "timeout\n";
219	};	249	};
220
221	# start the "loop" by creating the first watcher
222	$w = AnyEvent->timer (after => 0.5, cb => $cb);
223		250
224	=head3 TIMING ISSUES	251	=head3 TIMING ISSUES
225		252
226	There are two ways to handle timers: based on real time (relative, "fire	253	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	254	in 10 seconds") and based on wallclock time (absolute, "fire at 12
…		…
300	In either case, if you care (and in most cases, you don't), then you	327	In either case, if you care (and in most cases, you don't), then you
301	can get whatever behaviour you want with any event loop, by taking the	328	can get whatever behaviour you want with any event loop, by taking the
302	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	329	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
303	account.	330	account.
304		331
		332	=item AnyEvent->now_update
		333
		334	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		335	the current time for each loop iteration (see the discussion of L<<
		336	AnyEvent->now >>, above).
		337
		338	When a callback runs for a long time (or when the process sleeps), then
		339	this "current" time will differ substantially from the real time, which
		340	might affect timers and time-outs.
		341
		342	When this is the case, you can call this method, which will update the
		343	event loop's idea of "current time".
		344
		345	Note that updating the time I<might> cause some events to be handled.
		346
305	=back	347	=back
306		348
307	=head2 SIGNAL WATCHERS	349	=head2 SIGNAL WATCHERS
308		350
309	You can watch for signals using a signal watcher, C<signal> is the signal	351	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	352	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
311	be invoked whenever a signal occurs.	353	callback to be invoked whenever a signal occurs.
312		354
313	Although the callback might get passed parameters, their value and	355	Although the callback might get passed parameters, their value and
314	presence is undefined and you cannot rely on them. Portable AnyEvent	356	presence is undefined and you cannot rely on them. Portable AnyEvent
315	callbacks cannot use arguments passed to signal watcher callbacks.	357	callbacks cannot use arguments passed to signal watcher callbacks.
316		358
…		…
332	=head2 CHILD PROCESS WATCHERS	374	=head2 CHILD PROCESS WATCHERS
333		375
334	You can also watch on a child process exit and catch its exit status.	376	You can also watch on a child process exit and catch its exit status.
335		377
336	The child process is specified by the C<pid> argument (if set to C<0>, it	378	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	379	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	380	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	381	any trace events (stopped/continued).
340	and exit status (as returned by waitpid), so unlike other watcher types,	382
341	you I<can> rely on child watcher callback arguments.	383	The callback will be called with the pid and exit status (as returned by
		384	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		385	callback arguments.
		386
		387	This watcher type works by installing a signal handler for C<SIGCHLD>,
		388	and since it cannot be shared, nothing else should use SIGCHLD or reap
		389	random child processes (waiting for specific child processes, e.g. inside
		390	C<system>, is just fine).
342		391
343	There is a slight catch to child watchers, however: you usually start them	392	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	393	I<after> the child process was created, and this means the process could
345	have exited already (and no SIGCHLD will be sent anymore).	394	have exited already (and no SIGCHLD will be sent anymore).
346		395
…		…
352	AnyEvent program, you I<have> to create at least one watcher before you	401	AnyEvent program, you I<have> to create at least one watcher before you
353	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	402	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
354		403
355	Example: fork a process and wait for it	404	Example: fork a process and wait for it
356		405
357	my $done = AnyEvent->condvar;	406	my $done = AnyEvent->condvar;
358		407
359	my $pid = fork or exit 5;	408	my $pid = fork or exit 5;
360		409
361	my $w = AnyEvent->child (	410	my $w = AnyEvent->child (
362	pid => $pid,	411	pid => $pid,
363	cb => sub {	412	cb => sub {
364	my ($pid, $status) = @_;	413	my ($pid, $status) = @_;
365	warn "pid $pid exited with status $status";	414	warn "pid $pid exited with status $status";
366	$done->send;	415	$done->send;
367	},	416	},
368	);	417	);
369		418
370	# do something else, then wait for process exit	419	# do something else, then wait for process exit
371	$done->recv;	420	$done->recv;
		421
		422	=head2 IDLE WATCHERS
		423
		424	Sometimes there is a need to do something, but it is not so important
		425	to do it instantly, but only when there is nothing better to do. This
		426	"nothing better to do" is usually defined to be "no other events need
		427	attention by the event loop".
		428
		429	Idle watchers ideally get invoked when the event loop has nothing
		430	better to do, just before it would block the process to wait for new
		431	events. Instead of blocking, the idle watcher is invoked.
		432
		433	Most event loops unfortunately do not really support idle watchers (only
		434	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		435	will simply call the callback "from time to time".
		436
		437	Example: read lines from STDIN, but only process them when the
		438	program is otherwise idle:
		439
		440	my @lines; # read data
		441	my $idle_w;
		442	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		443	push @lines, scalar <STDIN>;
		444
		445	# start an idle watcher, if not already done
		446	$idle_w \|\|= AnyEvent->idle (cb => sub {
		447	# handle only one line, when there are lines left
		448	if (my $line = shift @lines) {
		449	print "handled when idle: $line";
		450	} else {
		451	# otherwise disable the idle watcher again
		452	undef $idle_w;
		453	}
		454	});
		455	});
372		456
373	=head2 CONDITION VARIABLES	457	=head2 CONDITION VARIABLES
374		458
375	If you are familiar with some event loops you will know that all of them	459	If you are familiar with some event loops you will know that all of them
376	require you to run some blocking "loop", "run" or similar function that	460	require you to run some blocking "loop", "run" or similar function that
…		…
382	The instrument to do that is called a "condition variable", so called	466	The instrument to do that is called a "condition variable", so called
383	because they represent a condition that must become true.	467	because they represent a condition that must become true.
384		468
385	Condition variables can be created by calling the C<< AnyEvent->condvar	469	Condition variables can be created by calling the C<< AnyEvent->condvar
386	>> method, usually without arguments. The only argument pair allowed is	470	>> method, usually without arguments. The only argument pair allowed is
		471
387	C<cb>, which specifies a callback to be called when the condition variable	472	C<cb>, which specifies a callback to be called when the condition variable
388	becomes true.	473	becomes true, with the condition variable as the first argument (but not
		474	the results).
389		475
390	After creation, the condition variable is "false" until it becomes "true"	476	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	477	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<<	478	were a callback, read about the caveats in the description for the C<<
393	->send >> method).	479	->send >> method).
…		…
449		535
450	my $done = AnyEvent->condvar;	536	my $done = AnyEvent->condvar;
451	my $delay = AnyEvent->timer (after => 5, cb => $done);	537	my $delay = AnyEvent->timer (after => 5, cb => $done);
452	$done->recv;	538	$done->recv;
453		539
		540	Example: Imagine an API that returns a condvar and doesn't support
		541	callbacks. This is how you make a synchronous call, for example from
		542	the main program:
		543
		544	use AnyEvent::CouchDB;
		545
		546	...
		547
		548	my @info = $couchdb->info->recv;
		549
		550	And this is how you would just ste a callback to be called whenever the
		551	results are available:
		552
		553	$couchdb->info->cb (sub {
		554	my @info = $_[0]->recv;
		555	});
		556
454	=head3 METHODS FOR PRODUCERS	557	=head3 METHODS FOR PRODUCERS
455		558
456	These methods should only be used by the producing side, i.e. the	559	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	560	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	561	the producer side which creates the condvar in most cases, but it isn't
…		…
591	=item $bool = $cv->ready	694	=item $bool = $cv->ready
592		695
593	Returns true when the condition is "true", i.e. whether C<send> or	696	Returns true when the condition is "true", i.e. whether C<send> or
594	C<croak> have been called.	697	C<croak> have been called.
595		698
596	=item $cb = $cv->cb ([new callback])	699	=item $cb = $cv->cb ($cb->($cv))
597		700
598	This is a mutator function that returns the callback set and optionally	701	This is a mutator function that returns the callback set and optionally
599	replaces it before doing so.	702	replaces it before doing so.
600		703
601	The callback will be called when the condition becomes "true", i.e. when	704	The callback will be called when the condition becomes "true", i.e. when
602	C<send> or C<croak> are called. Calling C<recv> inside the callback	705	C<send> or C<croak> are called, with the only argument being the condition
603	or at any later time is guaranteed not to block.	706	variable itself. Calling C<recv> inside the callback or at any later time
		707	is guaranteed not to block.
604		708
605	=back	709	=back
606		710
607	=head1 GLOBAL VARIABLES AND FUNCTIONS	711	=head1 GLOBAL VARIABLES AND FUNCTIONS
608		712
…		…
737	=item L<AnyEvent::Util>	841	=item L<AnyEvent::Util>
738		842
739	Contains various utility functions that replace often-used but blocking	843	Contains various utility functions that replace often-used but blocking
740	functions such as C<inet_aton> by event-/callback-based versions.	844	functions such as C<inet_aton> by event-/callback-based versions.
741		845
742	=item L<AnyEvent::Handle>
743
744	Provide read and write buffers and manages watchers for reads and writes.
745
746	=item L<AnyEvent::Socket>	846	=item L<AnyEvent::Socket>
747		847
748	Provides various utility functions for (internet protocol) sockets,	848	Provides various utility functions for (internet protocol) sockets,
749	addresses and name resolution. Also functions to create non-blocking tcp	849	addresses and name resolution. Also functions to create non-blocking tcp
750	connections or tcp servers, with IPv6 and SRV record support and more.	850	connections or tcp servers, with IPv6 and SRV record support and more.
751		851
		852	=item L<AnyEvent::Handle>
		853
		854	Provide read and write buffers, manages watchers for reads and writes,
		855	supports raw and formatted I/O, I/O queued and fully transparent and
		856	non-blocking SSL/TLS.
		857
752	=item L<AnyEvent::DNS>	858	=item L<AnyEvent::DNS>
753		859
754	Provides rich asynchronous DNS resolver capabilities.	860	Provides rich asynchronous DNS resolver capabilities.
755		861
		862	=item L<AnyEvent::HTTP>
		863
		864	A simple-to-use HTTP library that is capable of making a lot of concurrent
		865	HTTP requests.
		866
756	=item L<AnyEvent::HTTPD>	867	=item L<AnyEvent::HTTPD>
757		868
758	Provides a simple web application server framework.	869	Provides a simple web application server framework.
759		870
760	=item L<AnyEvent::FastPing>	871	=item L<AnyEvent::FastPing>
761		872
762	The fastest ping in the west.	873	The fastest ping in the west.
763		874
		875	=item L<AnyEvent::DBI>
		876
		877	Executes L<DBI> requests asynchronously in a proxy process.
		878
		879	=item L<AnyEvent::AIO>
		880
		881	Truly asynchronous I/O, should be in the toolbox of every event
		882	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		883	together.
		884
		885	=item L<AnyEvent::BDB>
		886
		887	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		888	L<BDB> and AnyEvent together.
		889
		890	=item L<AnyEvent::GPSD>
		891
		892	A non-blocking interface to gpsd, a daemon delivering GPS information.
		893
		894	=item L<AnyEvent::IGS>
		895
		896	A non-blocking interface to the Internet Go Server protocol (used by
		897	L<App::IGS>).
		898
764	=item L<Net::IRC3>	899	=item L<AnyEvent::IRC>
765		900
766	AnyEvent based IRC client module family.	901	AnyEvent based IRC client module family (replacing the older Net::IRC3).
767		902
768	=item L<Net::XMPP2>	903	=item L<Net::XMPP2>
769		904
770	AnyEvent based XMPP (Jabber protocol) module family.	905	AnyEvent based XMPP (Jabber protocol) module family.
771		906
…		…
780		915
781	=item L<Coro>	916	=item L<Coro>
782		917
783	Has special support for AnyEvent via L<Coro::AnyEvent>.	918	Has special support for AnyEvent via L<Coro::AnyEvent>.
784		919
785	=item L<AnyEvent::AIO>, L<IO::AIO>
786
787	Truly asynchronous I/O, should be in the toolbox of every event
788	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
789	together.
790
791	=item L<AnyEvent::BDB>, L<BDB>
792
793	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
794	IO::AIO and AnyEvent together.
795
796	=item L<IO::Lambda>	920	=item L<IO::Lambda>
797		921
798	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	922	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
799		923
800	=back	924	=back
…		…
802	=cut	926	=cut
803		927
804	package AnyEvent;	928	package AnyEvent;
805		929
806	no warnings;	930	no warnings;
807	use strict;	931	use strict qw(vars subs);
808		932
809	use Carp;	933	use Carp;
810		934
811	our $VERSION = 4.11;	935	our $VERSION = 4.41;
812	our $MODEL;	936	our $MODEL;
813		937
814	our $AUTOLOAD;	938	our $AUTOLOAD;
815	our @ISA;	939	our @ISA;
816		940
…		…
848	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	972	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
849	[Wx:: => AnyEvent::Impl::POE::],	973	[Wx:: => AnyEvent::Impl::POE::],
850	[Prima:: => AnyEvent::Impl::POE::],	974	[Prima:: => AnyEvent::Impl::POE::],
851	);	975	);
852		976
853	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	977	our %method = map +($_ => 1),
		978	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
854		979
855	our @post_detect;	980	our @post_detect;
856		981
857	sub post_detect(&) {	982	sub post_detect(&) {
858	my ($cb) = @_;	983	my ($cb) = @_;
…		…
863	1	988	1
864	} else {	989	} else {
865	push @post_detect, $cb;	990	push @post_detect, $cb;
866		991
867	defined wantarray	992	defined wantarray
868	? bless \$cb, "AnyEvent::Util::PostDetect"	993	? bless \$cb, "AnyEvent::Util::postdetect"
869	: ()	994	: ()
870	}	995	}
871	}	996	}
872		997
873	sub AnyEvent::Util::PostDetect::DESTROY {	998	sub AnyEvent::Util::postdetect::DESTROY {
874	@post_detect = grep $_ != ${$_[0]}, @post_detect;	999	@post_detect = grep $_ != ${$_[0]}, @post_detect;
875	}	1000	}
876		1001
877	sub detect() {	1002	sub detect() {
878	unless ($MODEL) {	1003	unless ($MODEL) {
…		…
915	last;	1040	last;
916	}	1041	}
917	}	1042	}
918		1043
919	$MODEL	1044	$MODEL
920	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1045	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
921	}	1046	}
922	}	1047	}
923		1048
		1049	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1050
924	unshift @ISA, $MODEL;	1051	unshift @ISA, $MODEL;
925	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1052
		1053	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
926		1054
927	(shift @post_detect)->() while @post_detect;	1055	(shift @post_detect)->() while @post_detect;
928	}	1056	}
929		1057
930	$MODEL	1058	$MODEL
…		…
940		1068
941	my $class = shift;	1069	my $class = shift;
942	$class->$func (@_);	1070	$class->$func (@_);
943	}	1071	}
944		1072
		1073	# utility function to dup a filehandle. this is used by many backends
		1074	# to support binding more than one watcher per filehandle (they usually
		1075	# allow only one watcher per fd, so we dup it to get a different one).
		1076	sub _dupfh($$$$) {
		1077	my ($poll, $fh, $r, $w) = @_;
		1078
		1079	# cygwin requires the fh mode to be matching, unix doesn't
		1080	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		1081	: $poll eq "w" ? ($w, ">")
		1082	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		1083
		1084	open my $fh2, "$mode&" . fileno $fh
		1085	or die "cannot dup() filehandle: $!,";
		1086
		1087	# we assume CLOEXEC is already set by perl in all important cases
		1088
		1089	($fh2, $rw)
		1090	}
		1091
945	package AnyEvent::Base;	1092	package AnyEvent::Base;
946		1093
947	# default implementation for now and time	1094	# default implementations for many methods
948		1095
949	use Time::HiRes ();	1096	BEGIN {
		1097	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1098	*_time = \&Time::HiRes::time;
		1099	# if (eval "use POSIX (); (POSIX::times())...
		1100	} else {
		1101	*_time = sub { time }; # epic fail
		1102	}
		1103	}
950		1104
951	sub time { Time::HiRes::time }	1105	sub time { _time }
952	sub now { Time::HiRes::time }	1106	sub now { _time }
		1107	sub now_update { }
953		1108
954	# default implementation for ->condvar	1109	# default implementation for ->condvar
955		1110
956	sub condvar {	1111	sub condvar {
957	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1112	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
958	}	1113	}
959		1114
960	# default implementation for ->signal	1115	# default implementation for ->signal
961		1116
962	our %SIG_CB;	1117	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1118
		1119	sub _signal_exec {
		1120	sysread $SIGPIPE_R, my $dummy, 4;
		1121
		1122	while (%SIG_EV) {
		1123	for (keys %SIG_EV) {
		1124	delete $SIG_EV{$_};
		1125	$_->() for values %{ $SIG_CB{$_} \|\| {} };
		1126	}
		1127	}
		1128	}
963		1129
964	sub signal {	1130	sub signal {
965	my (undef, %arg) = @_;	1131	my (undef, %arg) = @_;
966		1132
		1133	unless ($SIGPIPE_R) {
		1134	require Fcntl;
		1135
		1136	if (AnyEvent::WIN32) {
		1137	require AnyEvent::Util;
		1138
		1139	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1140	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1141	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1142	} else {
		1143	pipe $SIGPIPE_R, $SIGPIPE_W;
		1144	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1145	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1146	}
		1147
		1148	$SIGPIPE_R
		1149	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1150
		1151	# not strictly required, as $^F is normally 2, but let's make sure...
		1152	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1153	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1154
		1155	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1156	}
		1157
967	my $signal = uc $arg{signal}	1158	my $signal = uc $arg{signal}
968	or Carp::croak "required option 'signal' is missing";	1159	or Carp::croak "required option 'signal' is missing";
969		1160
970	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1161	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
971	$SIG{$signal} \|\|= sub {	1162	$SIG{$signal} \|\|= sub {
972	$_->() for values %{ $SIG_CB{$signal} \|\| {} };	1163	local $!;
		1164	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1165	undef $SIG_EV{$signal};
973	};	1166	};
974		1167
975	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1168	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
976	}	1169	}
977		1170
978	sub AnyEvent::Base::Signal::DESTROY {	1171	sub AnyEvent::Base::signal::DESTROY {
979	my ($signal, $cb) = @{$_[0]};	1172	my ($signal, $cb) = @{$_[0]};
980		1173
981	delete $SIG_CB{$signal}{$cb};	1174	delete $SIG_CB{$signal}{$cb};
982		1175
		1176	# delete doesn't work with older perls - they then
		1177	# print weird messages, or just unconditionally exit
		1178	# instead of getting the default action.
983	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1179	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
984	}	1180	}
985		1181
986	# default implementation for ->child	1182	# default implementation for ->child
987		1183
988	our %PID_CB;	1184	our %PID_CB;
989	our $CHLD_W;	1185	our $CHLD_W;
990	our $CHLD_DELAY_W;	1186	our $CHLD_DELAY_W;
991	our $PID_IDLE;
992	our $WNOHANG;	1187	our $WNOHANG;
993		1188
994	sub _child_wait {	1189	sub _sigchld {
995	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1190	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
996	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),	1191	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),
997	(values %{ $PID_CB{0} \|\| {} });	1192	(values %{ $PID_CB{0} \|\| {} });
998	}	1193	}
999
1000	undef $PID_IDLE;
1001	}
1002
1003	sub _sigchld {
1004	# make sure we deliver these changes "synchronous" with the event loop.
1005	$CHLD_DELAY_W \|\|= AnyEvent->timer (after => 0, cb => sub {
1006	undef $CHLD_DELAY_W;
1007	&_child_wait;
1008	});
1009	}	1194	}
1010		1195
1011	sub child {	1196	sub child {
1012	my (undef, %arg) = @_;	1197	my (undef, %arg) = @_;
1013		1198
1014	defined (my $pid = $arg{pid} + 0)	1199	defined (my $pid = $arg{pid} + 0)
1015	or Carp::croak "required option 'pid' is missing";	1200	or Carp::croak "required option 'pid' is missing";
1016		1201
1017	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1202	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1018		1203
1019	unless ($WNOHANG) {
1020	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;	1204	$WNOHANG \|\|= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
1021	}
1022		1205
1023	unless ($CHLD_W) {	1206	unless ($CHLD_W) {
1024	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1207	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1025	# child could be a zombie already, so make at least one round	1208	# child could be a zombie already, so make at least one round
1026	&_sigchld;	1209	&_sigchld;
1027	}	1210	}
1028		1211
1029	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1212	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1030	}	1213	}
1031		1214
1032	sub AnyEvent::Base::Child::DESTROY {	1215	sub AnyEvent::Base::child::DESTROY {
1033	my ($pid, $cb) = @{$_[0]};	1216	my ($pid, $cb) = @{$_[0]};
1034		1217
1035	delete $PID_CB{$pid}{$cb};	1218	delete $PID_CB{$pid}{$cb};
1036	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1219	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1037		1220
1038	undef $CHLD_W unless keys %PID_CB;	1221	undef $CHLD_W unless keys %PID_CB;
		1222	}
		1223
		1224	# idle emulation is done by simply using a timer, regardless
		1225	# of whether the process is idle or not, and not letting
		1226	# the callback use more than 50% of the time.
		1227	sub idle {
		1228	my (undef, %arg) = @_;
		1229
		1230	my ($cb, $w, $rcb) = $arg{cb};
		1231
		1232	$rcb = sub {
		1233	if ($cb) {
		1234	$w = _time;
		1235	&$cb;
		1236	$w = _time - $w;
		1237
		1238	# never use more then 50% of the time for the idle watcher,
		1239	# within some limits
		1240	$w = 0.0001 if $w < 0.0001;
		1241	$w = 5 if $w > 5;
		1242
		1243	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1244	} else {
		1245	# clean up...
		1246	undef $w;
		1247	undef $rcb;
		1248	}
		1249	};
		1250
		1251	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1252
		1253	bless \\$cb, "AnyEvent::Base::idle"
		1254	}
		1255
		1256	sub AnyEvent::Base::idle::DESTROY {
		1257	undef $${$_[0]};
1039	}	1258	}
1040		1259
1041	package AnyEvent::CondVar;	1260	package AnyEvent::CondVar;
1042		1261
1043	our @ISA = AnyEvent::CondVar::Base::;	1262	our @ISA = AnyEvent::CondVar::Base::;
…		…
1095	}	1314	}
1096		1315
1097	# undocumented/compatibility with pre-3.4	1316	# undocumented/compatibility with pre-3.4
1098	*broadcast = \&send;	1317	*broadcast = \&send;
1099	*wait = \&_wait;	1318	*wait = \&_wait;
		1319
		1320	=head1 ERROR AND EXCEPTION HANDLING
		1321
		1322	In general, AnyEvent does not do any error handling - it relies on the
		1323	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1324	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1325	checking of all AnyEvent methods, however, which is highly useful during
		1326	development.
		1327
		1328	As for exception handling (i.e. runtime errors and exceptions thrown while
		1329	executing a callback), this is not only highly event-loop specific, but
		1330	also not in any way wrapped by this module, as this is the job of the main
		1331	program.
		1332
		1333	The pure perl event loop simply re-throws the exception (usually
		1334	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1335	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1336	so on.
		1337
		1338	=head1 ENVIRONMENT VARIABLES
		1339
		1340	The following environment variables are used by this module or its
		1341	submodules:
		1342
		1343	=over 4
		1344
		1345	=item C<PERL_ANYEVENT_VERBOSE>
		1346
		1347	By default, AnyEvent will be completely silent except in fatal
		1348	conditions. You can set this environment variable to make AnyEvent more
		1349	talkative.
		1350
		1351	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1352	conditions, such as not being able to load the event model specified by
		1353	C<PERL_ANYEVENT_MODEL>.
		1354
		1355	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1356	model it chooses.
		1357
		1358	=item C<PERL_ANYEVENT_STRICT>
		1359
		1360	AnyEvent does not do much argument checking by default, as thorough
		1361	argument checking is very costly. Setting this variable to a true value
		1362	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1363	check the arguments passed to most method calls. If it finds any problems
		1364	it will croak.
		1365
		1366	In other words, enables "strict" mode.
		1367
		1368	Unlike C<use strict>, it is definitely recommended ot keep it off in
		1369	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1370	developing programs can be very useful, however.
		1371
		1372	=item C<PERL_ANYEVENT_MODEL>
		1373
		1374	This can be used to specify the event model to be used by AnyEvent, before
		1375	auto detection and -probing kicks in. It must be a string consisting
		1376	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1377	and the resulting module name is loaded and if the load was successful,
		1378	used as event model. If it fails to load AnyEvent will proceed with
		1379	auto detection and -probing.
		1380
		1381	This functionality might change in future versions.
		1382
		1383	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1384	could start your program like this:
		1385
		1386	PERL_ANYEVENT_MODEL=Perl perl ...
		1387
		1388	=item C<PERL_ANYEVENT_PROTOCOLS>
		1389
		1390	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1391	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1392	of auto probing).
		1393
		1394	Must be set to a comma-separated list of protocols or address families,
		1395	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1396	used, and preference will be given to protocols mentioned earlier in the
		1397	list.
		1398
		1399	This variable can effectively be used for denial-of-service attacks
		1400	against local programs (e.g. when setuid), although the impact is likely
		1401	small, as the program has to handle conenction and other failures anyways.
		1402
		1403	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1404	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1405	- only support IPv4, never try to resolve or contact IPv6
		1406	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1407	IPv6, but prefer IPv6 over IPv4.
		1408
		1409	=item C<PERL_ANYEVENT_EDNS0>
		1410
		1411	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1412	for DNS. This extension is generally useful to reduce DNS traffic, but
		1413	some (broken) firewalls drop such DNS packets, which is why it is off by
		1414	default.
		1415
		1416	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1417	EDNS0 in its DNS requests.
		1418
		1419	=item C<PERL_ANYEVENT_MAX_FORKS>
		1420
		1421	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1422	will create in parallel.
		1423
		1424	=back
1100		1425
1101	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1426	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1102		1427
1103	This is an advanced topic that you do not normally need to use AnyEvent in	1428	This is an advanced topic that you do not normally need to use AnyEvent in
1104	a module. This section is only of use to event loop authors who want to	1429	a module. This section is only of use to event loop authors who want to
…		…
1138		1463
1139	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1464	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1140	condition variables: code blocking while waiting for a condition will	1465	condition variables: code blocking while waiting for a condition will
1141	C<die>. This still works with most modules/usages, and blocking calls must	1466	C<die>. This still works with most modules/usages, and blocking calls must
1142	not be done in an interactive application, so it makes sense.	1467	not be done in an interactive application, so it makes sense.
1143
1144	=head1 ENVIRONMENT VARIABLES
1145
1146	The following environment variables are used by this module:
1147
1148	=over 4
1149
1150	=item C<PERL_ANYEVENT_VERBOSE>
1151
1152	By default, AnyEvent will be completely silent except in fatal
1153	conditions. You can set this environment variable to make AnyEvent more
1154	talkative.
1155
1156	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1157	conditions, such as not being able to load the event model specified by
1158	C<PERL_ANYEVENT_MODEL>.
1159
1160	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1161	model it chooses.
1162
1163	=item C<PERL_ANYEVENT_MODEL>
1164
1165	This can be used to specify the event model to be used by AnyEvent, before
1166	auto detection and -probing kicks in. It must be a string consisting
1167	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1168	and the resulting module name is loaded and if the load was successful,
1169	used as event model. If it fails to load AnyEvent will proceed with
1170	auto detection and -probing.
1171
1172	This functionality might change in future versions.
1173
1174	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1175	could start your program like this:
1176
1177	PERL_ANYEVENT_MODEL=Perl perl ...
1178
1179	=item C<PERL_ANYEVENT_PROTOCOLS>
1180
1181	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1182	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1183	of auto probing).
1184
1185	Must be set to a comma-separated list of protocols or address families,
1186	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1187	used, and preference will be given to protocols mentioned earlier in the
1188	list.
1189
1190	This variable can effectively be used for denial-of-service attacks
1191	against local programs (e.g. when setuid), although the impact is likely
1192	small, as the program has to handle connection errors already-
1193
1194	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1195	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1196	- only support IPv4, never try to resolve or contact IPv6
1197	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1198	IPv6, but prefer IPv6 over IPv4.
1199
1200	=item C<PERL_ANYEVENT_EDNS0>
1201
1202	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1203	for DNS. This extension is generally useful to reduce DNS traffic, but
1204	some (broken) firewalls drop such DNS packets, which is why it is off by
1205	default.
1206
1207	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1208	EDNS0 in its DNS requests.
1209
1210	=item C<PERL_ANYEVENT_MAX_FORKS>
1211
1212	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1213	will create in parallel.
1214
1215	=back
1216		1468
1217	=head1 EXAMPLE PROGRAM	1469	=head1 EXAMPLE PROGRAM
1218		1470
1219	The following program uses an I/O watcher to read data from STDIN, a timer	1471	The following program uses an I/O watcher to read data from STDIN, a timer
1220	to display a message once per second, and a condition variable to quit the	1472	to display a message once per second, and a condition variable to quit the
…		…
1414	watcher.	1666	watcher.
1415		1667
1416	=head3 Results	1668	=head3 Results
1417		1669
1418	name watchers bytes create invoke destroy comment	1670	name watchers bytes create invoke destroy comment
1419	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1671	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1420	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1672	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1421	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1673	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1422	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1674	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1423	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1675	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1424	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	1676	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1425	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1677	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1426	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1678	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1427	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1679	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1428	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1680	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1429		1681
1430	=head3 Discussion	1682	=head3 Discussion
1431		1683
1432	The benchmark does I<not> measure scalability of the event loop very	1684	The benchmark does I<not> measure scalability of the event loop very
1433	well. For example, a select-based event loop (such as the pure perl one)	1685	well. For example, a select-based event loop (such as the pure perl one)
…		…
1635	watchers, as the management overhead dominates.	1887	watchers, as the management overhead dominates.
1636		1888
1637	=back	1889	=back
1638		1890
1639		1891
		1892	=head1 SIGNALS
		1893
		1894	AnyEvent currently installs handlers for these signals:
		1895
		1896	=over 4
		1897
		1898	=item SIGCHLD
		1899
		1900	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		1901	emulation for event loops that do not support them natively. Also, some
		1902	event loops install a similar handler.
		1903
		1904	=item SIGPIPE
		1905
		1906	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		1907	when AnyEvent gets loaded.
		1908
		1909	The rationale for this is that AnyEvent users usually do not really depend
		1910	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		1911	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		1912	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		1913	some random socket.
		1914
		1915	The rationale for installing a no-op handler as opposed to ignoring it is
		1916	that this way, the handler will be restored to defaults on exec.
		1917
		1918	Feel free to install your own handler, or reset it to defaults.
		1919
		1920	=back
		1921
		1922	=cut
		1923
		1924	$SIG{PIPE} = sub { }
		1925	unless defined $SIG{PIPE};
		1926
		1927
1640	=head1 FORK	1928	=head1 FORK
1641		1929
1642	Most event libraries are not fork-safe. The ones who are usually are	1930	Most event libraries are not fork-safe. The ones who are usually are
1643	because they rely on inefficient but fork-safe C<select> or C<poll>	1931	because they rely on inefficient but fork-safe C<select> or C<poll>
1644	calls. Only L<EV> is fully fork-aware.	1932	calls. Only L<EV> is fully fork-aware.
…		…
1657	specified in the variable.	1945	specified in the variable.
1658		1946
1659	You can make AnyEvent completely ignore this variable by deleting it	1947	You can make AnyEvent completely ignore this variable by deleting it
1660	before the first watcher gets created, e.g. with a C<BEGIN> block:	1948	before the first watcher gets created, e.g. with a C<BEGIN> block:
1661		1949
1662	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1950	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1663		1951
1664	use AnyEvent;	1952	use AnyEvent;
1665		1953
1666	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1954	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1667	be used to probe what backend is used and gain other information (which is	1955	be used to probe what backend is used and gain other information (which is
1668	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	1956	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1957	$ENV{PERL_ANYEGENT_STRICT}.
		1958
		1959
		1960	=head1 BUGS
		1961
		1962	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		1963	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		1964	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		1965	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
		1966	pronounced).
1669		1967
1670		1968
1671	=head1 SEE ALSO	1969	=head1 SEE ALSO
1672		1970
1673	Utility functions: L<AnyEvent::Util>.	1971	Utility functions: L<AnyEvent::Util>.
…		…
1690	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	1988	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1691		1989
1692		1990
1693	=head1 AUTHOR	1991	=head1 AUTHOR
1694		1992
1695	Marc Lehmann <schmorp@schmorp.de>	1993	Marc Lehmann <schmorp@schmorp.de>
1696	http://home.schmorp.de/	1994	http://home.schmorp.de/
1697		1995
1698	=cut	1996	=cut
1699		1997
1700	1	1998	1
1701		1999

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.148 by root, Sat May 31 00:40:16 2008 UTC vs. Revision 1.210 by root, Wed May 13 15:19:43 2009 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.148 by root, Sat May 31 00:40:16 2008 UTC vs.
Revision 1.210 by root, Wed May 13 15:19:43 2009 UTC