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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.133 by root, Sun May 25 03:44:03 2008 UTC vs.
Revision 1.196 by root, Thu Mar 26 07:47:42 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	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 });
		31
		32	=head1 INTRODUCTION/TUTORIAL
		33
		34	This manpage is mainly a reference manual. If you are interested
		35	in a tutorial or some gentle introduction, have a look at the
		36	L<AnyEvent::Intro> manpage.
22		37
23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	38	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24		39
25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	40	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26	nowadays. So what is different about AnyEvent?	41	nowadays. So what is different about AnyEvent?
27		42
28	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of	43	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
29	policy> and AnyEvent is I<small and efficient>.	44	policy> and AnyEvent is I<small and efficient>.
30		45
31	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
32	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
33	pragmatic way. For event models and certain classes of immortals alike,	48	pragmatic way. For event models and certain classes of immortals alike,
34	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,
35	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
36	helps hiding the differences between those event loops.	51	cannot change this, but it can hide the differences between those event
		52	loops.
37		53
38	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
39	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
40	religion, a way of living, and most importantly: without forcing your	56	religion, a way of living, and most importantly: without forcing your
41	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
42	model you use.	58	model you use.
43		59
44	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
45	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
46	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
47	cannot use anything else, as it is simply incompatible to everything that	63	cannot use anything else, as they are simply incompatible to everything
48	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
49	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.
50		66
51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	67	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52	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
53	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
54	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,
55	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
56	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
57	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
58	event loops to AnyEvent, too, so it is future-proof).	74	to AnyEvent, too, so it is future-proof).
59		75
60	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
61	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
62	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
63	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
64	offering the functionality that is necessary, in as thin as a wrapper as	80	offering the functionality that is necessary, in as thin as a wrapper as
65	technically possible.	81	technically possible.
66		82
		83	Of course, AnyEvent comes with a big (and fully optional!) toolbox
		84	of useful functionality, such as an asynchronous DNS resolver, 100%
		85	non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
		86	such as Windows) and lots of real-world knowledge and workarounds for
		87	platform bugs and differences.
		88
67	Of course, if you want lots of policy (this can arguably be somewhat	89	Now, if you I<do want> lots of policy (this can arguably be somewhat
68	useful) and you want to force your users to use the one and only event	90	useful) and you want to force your users to use the one and only event
69	model, you should I<not> use this module.	91	model, you should I<not> use this module.
70		92
71	=head1 DESCRIPTION	93	=head1 DESCRIPTION
72		94
102	starts using it, all bets are off. Maybe you should tell their authors to	124	starts using it, all bets are off. Maybe you should tell their authors to
103	use AnyEvent so their modules work together with others seamlessly...	125	use AnyEvent so their modules work together with others seamlessly...
104		126
105	The pure-perl implementation of AnyEvent is called	127	The pure-perl implementation of AnyEvent is called
106	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	128	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
107	explicitly.	129	explicitly and enjoy the high availability of that event loop :)
108		130
109	=head1 WATCHERS	131	=head1 WATCHERS
110		132
111	AnyEvent has the central concept of a I<watcher>, which is an object that	133	AnyEvent has the central concept of a I<watcher>, which is an object that
112	stores relevant data for each kind of event you are waiting for, such as	134	stores relevant data for each kind of event you are waiting for, such as
…		…
115	These watchers are normal Perl objects with normal Perl lifetime. After	137	These watchers are normal Perl objects with normal Perl lifetime. After
116	creating a watcher it will immediately "watch" for events and invoke the	138	creating a watcher it will immediately "watch" for events and invoke the
117	callback when the event occurs (of course, only when the event model	139	callback when the event occurs (of course, only when the event model
118	is in control).	140	is in control).
119		141
		142	Note that B<callbacks must not permanently change global variables>
		143	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
		144	callbacks must not C<die> >>. The former is good programming practise in
		145	Perl and the latter stems from the fact that exception handling differs
		146	widely between event loops.
		147
120	To disable the watcher you have to destroy it (e.g. by setting the	148	To disable the watcher you have to destroy it (e.g. by setting the
121	variable you store it in to C<undef> or otherwise deleting all references	149	variable you store it in to C<undef> or otherwise deleting all references
122	to it).	150	to it).
123		151
124	All watchers are created by calling a method on the C<AnyEvent> class.	152	All watchers are created by calling a method on the C<AnyEvent> class.
…		…
126	Many watchers either are used with "recursion" (repeating timers for	154	Many watchers either are used with "recursion" (repeating timers for
127	example), or need to refer to their watcher object in other ways.	155	example), or need to refer to their watcher object in other ways.
128		156
129	An any way to achieve that is this pattern:	157	An any way to achieve that is this pattern:
130		158
131	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	159	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
132	# you can use $w here, for example to undef it	160	# you can use $w here, for example to undef it
133	undef $w;	161	undef $w;
134	});	162	});
135		163
136	Note that C<my $w; $w => combination. This is necessary because in Perl,	164	Note that C<my $w; $w => combination. This is necessary because in Perl,
137	my variables are only visible after the statement in which they are	165	my variables are only visible after the statement in which they are
138	declared.	166	declared.
139		167
140	=head2 I/O WATCHERS	168	=head2 I/O WATCHERS
141		169
142	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	170	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
143	with the following mandatory key-value pairs as arguments:	171	with the following mandatory key-value pairs as arguments:
144		172
145	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	173	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events
146	for events. C<poll> must be a string that is either C<r> or C<w>,	174	(AnyEvent might or might not keep a reference to this file handle). C<poll>
147	which creates a watcher waiting for "r"eadable or "w"ritable events,	175	must be a string that is either C<r> or C<w>, which creates a watcher
148	respectively. C<cb> is the callback to invoke each time the file handle	176	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the
149	becomes ready.	177	callback to invoke each time the file handle becomes ready.
150		178
151	Although the callback might get passed parameters, their value and	179	Although the callback might get passed parameters, their value and
152	presence is undefined and you cannot rely on them. Portable AnyEvent	180	presence is undefined and you cannot rely on them. Portable AnyEvent
153	callbacks cannot use arguments passed to I/O watcher callbacks.	181	callbacks cannot use arguments passed to I/O watcher callbacks.
154		182
…		…
158		186
159	Some event loops issue spurious readyness notifications, so you should	187	Some event loops issue spurious readyness notifications, so you should
160	always use non-blocking calls when reading/writing from/to your file	188	always use non-blocking calls when reading/writing from/to your file
161	handles.	189	handles.
162		190
163	Example:
164
165	# wait for readability of STDIN, then read a line and disable the watcher	191	Example: wait for readability of STDIN, then read a line and disable the
		192	watcher.
		193
166	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	194	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
167	chomp (my $input = <STDIN>);	195	chomp (my $input = <STDIN>);
168	warn "read: $input\n";	196	warn "read: $input\n";
169	undef $w;	197	undef $w;
170	});	198	});
…		…
180		208
181	Although the callback might get passed parameters, their value and	209	Although the callback might get passed parameters, their value and
182	presence is undefined and you cannot rely on them. Portable AnyEvent	210	presence is undefined and you cannot rely on them. Portable AnyEvent
183	callbacks cannot use arguments passed to time watcher callbacks.	211	callbacks cannot use arguments passed to time watcher callbacks.
184		212
185	The timer callback will be invoked at most once: if you want a repeating	213	The callback will normally be invoked once only. If you specify another
186	timer you have to create a new watcher (this is a limitation by both Tk	214	parameter, C<interval>, as a strictly positive number (> 0), then the
187	and Glib).	215	callback will be invoked regularly at that interval (in fractional
		216	seconds) after the first invocation. If C<interval> is specified with a
		217	false value, then it is treated as if it were missing.
188		218
189	Example:	219	The callback will be rescheduled before invoking the callback, but no
		220	attempt is done to avoid timer drift in most backends, so the interval is
		221	only approximate.
190		222
191	# fire an event after 7.7 seconds	223	Example: fire an event after 7.7 seconds.
		224
192	my $w = AnyEvent->timer (after => 7.7, cb => sub {	225	my $w = AnyEvent->timer (after => 7.7, cb => sub {
193	warn "timeout\n";	226	warn "timeout\n";
194	});	227	});
195		228
196	# to cancel the timer:	229	# to cancel the timer:
197	undef $w;	230	undef $w;
198		231
199	Example 2:
200
201	# fire an event after 0.5 seconds, then roughly every second	232	Example 2: fire an event after 0.5 seconds, then roughly every second.
202	my $w;
203		233
204	my $cb = sub {
205	# cancel the old timer while creating a new one
206	$w = AnyEvent->timer (after => 1, cb => $cb);	234	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		235	warn "timeout\n";
207	};	236	};
208
209	# start the "loop" by creating the first watcher
210	$w = AnyEvent->timer (after => 0.5, cb => $cb);
211		237
212	=head3 TIMING ISSUES	238	=head3 TIMING ISSUES
213		239
214	There are two ways to handle timers: based on real time (relative, "fire	240	There are two ways to handle timers: based on real time (relative, "fire
215	in 10 seconds") and based on wallclock time (absolute, "fire at 12	241	in 10 seconds") and based on wallclock time (absolute, "fire at 12
…		…
227	timers.	253	timers.
228		254
229	AnyEvent always prefers relative timers, if available, matching the	255	AnyEvent always prefers relative timers, if available, matching the
230	AnyEvent API.	256	AnyEvent API.
231		257
		258	AnyEvent has two additional methods that return the "current time":
		259
		260	=over 4
		261
		262	=item AnyEvent->time
		263
		264	This returns the "current wallclock time" as a fractional number of
		265	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
		266	return, and the result is guaranteed to be compatible with those).
		267
		268	It progresses independently of any event loop processing, i.e. each call
		269	will check the system clock, which usually gets updated frequently.
		270
		271	=item AnyEvent->now
		272
		273	This also returns the "current wallclock time", but unlike C<time>, above,
		274	this value might change only once per event loop iteration, depending on
		275	the event loop (most return the same time as C<time>, above). This is the
		276	time that AnyEvent's timers get scheduled against.
		277
		278	I<In almost all cases (in all cases if you don't care), this is the
		279	function to call when you want to know the current time.>
		280
		281	This function is also often faster then C<< AnyEvent->time >>, and
		282	thus the preferred method if you want some timestamp (for example,
		283	L<AnyEvent::Handle> uses this to update it's activity timeouts).
		284
		285	The rest of this section is only of relevance if you try to be very exact
		286	with your timing, you can skip it without bad conscience.
		287
		288	For a practical example of when these times differ, consider L<Event::Lib>
		289	and L<EV> and the following set-up:
		290
		291	The event loop is running and has just invoked one of your callback at
		292	time=500 (assume no other callbacks delay processing). In your callback,
		293	you wait a second by executing C<sleep 1> (blocking the process for a
		294	second) and then (at time=501) you create a relative timer that fires
		295	after three seconds.
		296
		297	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
		298	both return C<501>, because that is the current time, and the timer will
		299	be scheduled to fire at time=504 (C<501> + C<3>).
		300
		301	With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
		302	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
		303	last event processing phase started. With L<EV>, your timer gets scheduled
		304	to run at time=503 (C<500> + C<3>).
		305
		306	In one sense, L<Event::Lib> is more exact, as it uses the current time
		307	regardless of any delays introduced by event processing. However, most
		308	callbacks do not expect large delays in processing, so this causes a
		309	higher drift (and a lot more system calls to get the current time).
		310
		311	In another sense, L<EV> is more exact, as your timer will be scheduled at
		312	the same time, regardless of how long event processing actually took.
		313
		314	In either case, if you care (and in most cases, you don't), then you
		315	can get whatever behaviour you want with any event loop, by taking the
		316	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
		317	account.
		318
		319	=back
		320
232	=head2 SIGNAL WATCHERS	321	=head2 SIGNAL WATCHERS
233		322
234	You can watch for signals using a signal watcher, C<signal> is the signal	323	You can watch for signals using a signal watcher, C<signal> is the signal
235	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to	324	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
236	be invoked whenever a signal occurs.	325	callback to be invoked whenever a signal occurs.
237		326
238	Although the callback might get passed parameters, their value and	327	Although the callback might get passed parameters, their value and
239	presence is undefined and you cannot rely on them. Portable AnyEvent	328	presence is undefined and you cannot rely on them. Portable AnyEvent
240	callbacks cannot use arguments passed to signal watcher callbacks.	329	callbacks cannot use arguments passed to signal watcher callbacks.
241		330
…		…
257	=head2 CHILD PROCESS WATCHERS	346	=head2 CHILD PROCESS WATCHERS
258		347
259	You can also watch on a child process exit and catch its exit status.	348	You can also watch on a child process exit and catch its exit status.
260		349
261	The child process is specified by the C<pid> argument (if set to C<0>, it	350	The child process is specified by the C<pid> argument (if set to C<0>, it
262	watches for any child process exit). The watcher will trigger as often	351	watches for any child process exit). The watcher will triggered only when
263	as status change for the child are received. This works by installing a	352	the child process has finished and an exit status is available, not on
264	signal handler for C<SIGCHLD>. The callback will be called with the pid	353	any trace events (stopped/continued).
265	and exit status (as returned by waitpid), so unlike other watcher types,	354
266	you I<can> rely on child watcher callback arguments.	355	The callback will be called with the pid and exit status (as returned by
		356	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		357	callback arguments.
		358
		359	This watcher type works by installing a signal handler for C<SIGCHLD>,
		360	and since it cannot be shared, nothing else should use SIGCHLD or reap
		361	random child processes (waiting for specific child processes, e.g. inside
		362	C<system>, is just fine).
267		363
268	There is a slight catch to child watchers, however: you usually start them	364	There is a slight catch to child watchers, however: you usually start them
269	I<after> the child process was created, and this means the process could	365	I<after> the child process was created, and this means the process could
270	have exited already (and no SIGCHLD will be sent anymore).	366	have exited already (and no SIGCHLD will be sent anymore).
271		367
…		…
277	AnyEvent program, you I<have> to create at least one watcher before you	373	AnyEvent program, you I<have> to create at least one watcher before you
278	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	374	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
279		375
280	Example: fork a process and wait for it	376	Example: fork a process and wait for it
281		377
282	my $done = AnyEvent->condvar;	378	my $done = AnyEvent->condvar;
283		379
284	my $pid = fork or exit 5;	380	my $pid = fork or exit 5;
285		381
286	my $w = AnyEvent->child (	382	my $w = AnyEvent->child (
287	pid => $pid,	383	pid => $pid,
288	cb => sub {	384	cb => sub {
289	my ($pid, $status) = @_;	385	my ($pid, $status) = @_;
290	warn "pid $pid exited with status $status";	386	warn "pid $pid exited with status $status";
291	$done->send;	387	$done->send;
292	},	388	},
293	);	389	);
294		390
295	# do something else, then wait for process exit	391	# do something else, then wait for process exit
296	$done->recv;	392	$done->recv;
297		393
298	=head2 CONDITION VARIABLES	394	=head2 CONDITION VARIABLES
299		395
300	If you are familiar with some event loops you will know that all of them	396	If you are familiar with some event loops you will know that all of them
301	require you to run some blocking "loop", "run" or similar function that	397	require you to run some blocking "loop", "run" or similar function that
…		…
307	The instrument to do that is called a "condition variable", so called	403	The instrument to do that is called a "condition variable", so called
308	because they represent a condition that must become true.	404	because they represent a condition that must become true.
309		405
310	Condition variables can be created by calling the C<< AnyEvent->condvar	406	Condition variables can be created by calling the C<< AnyEvent->condvar
311	>> method, usually without arguments. The only argument pair allowed is	407	>> method, usually without arguments. The only argument pair allowed is
		408
312	C<cb>, which specifies a callback to be called when the condition variable	409	C<cb>, which specifies a callback to be called when the condition variable
313	becomes true.	410	becomes true, with the condition variable as the first argument (but not
		411	the results).
314		412
315	After creation, the condition variable is "false" until it becomes "true"	413	After creation, the condition variable is "false" until it becomes "true"
316	by calling the C<send> method (or calling the condition variable as if it	414	by calling the C<send> method (or calling the condition variable as if it
317	were a callback).	415	were a callback, read about the caveats in the description for the C<<
		416	->send >> method).
318		417
319	Condition variables are similar to callbacks, except that you can	418	Condition variables are similar to callbacks, except that you can
320	optionally wait for them. They can also be called merge points - points	419	optionally wait for them. They can also be called merge points - points
321	in time where multiple outstanding events have been processed. And yet	420	in time where multiple outstanding events have been processed. And yet
322	another way to call them is transactions - each condition variable can be	421	another way to call them is transactions - each condition variable can be
…		…
373		472
374	my $done = AnyEvent->condvar;	473	my $done = AnyEvent->condvar;
375	my $delay = AnyEvent->timer (after => 5, cb => $done);	474	my $delay = AnyEvent->timer (after => 5, cb => $done);
376	$done->recv;	475	$done->recv;
377		476
		477	Example: Imagine an API that returns a condvar and doesn't support
		478	callbacks. This is how you make a synchronous call, for example from
		479	the main program:
		480
		481	use AnyEvent::CouchDB;
		482
		483	...
		484
		485	my @info = $couchdb->info->recv;
		486
		487	And this is how you would just ste a callback to be called whenever the
		488	results are available:
		489
		490	$couchdb->info->cb (sub {
		491	my @info = $_[0]->recv;
		492	});
		493
378	=head3 METHODS FOR PRODUCERS	494	=head3 METHODS FOR PRODUCERS
379		495
380	These methods should only be used by the producing side, i.e. the	496	These methods should only be used by the producing side, i.e. the
381	code/module that eventually sends the signal. Note that it is also	497	code/module that eventually sends the signal. Note that it is also
382	the producer side which creates the condvar in most cases, but it isn't	498	the producer side which creates the condvar in most cases, but it isn't
…		…
394	immediately from within send.	510	immediately from within send.
395		511
396	Any arguments passed to the C<send> call will be returned by all	512	Any arguments passed to the C<send> call will be returned by all
397	future C<< ->recv >> calls.	513	future C<< ->recv >> calls.
398		514
399	Condition variables are overloaded so one can call them directly (as a	515	Condition variables are overloaded so one can call them directly
400	code reference). Calling them directly is the same as calling C<send>.	516	(as a code reference). Calling them directly is the same as calling
		517	C<send>. Note, however, that many C-based event loops do not handle
		518	overloading, so as tempting as it may be, passing a condition variable
		519	instead of a callback does not work. Both the pure perl and EV loops
		520	support overloading, however, as well as all functions that use perl to
		521	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
		522	example).
401		523
402	=item $cv->croak ($error)	524	=item $cv->croak ($error)
403		525
404	Similar to send, but causes all call's to C<< ->recv >> to invoke	526	Similar to send, but causes all call's to C<< ->recv >> to invoke
405	C<Carp::croak> with the given error message/object/scalar.	527	C<Carp::croak> with the given error message/object/scalar.
…		…
509	=item $bool = $cv->ready	631	=item $bool = $cv->ready
510		632
511	Returns true when the condition is "true", i.e. whether C<send> or	633	Returns true when the condition is "true", i.e. whether C<send> or
512	C<croak> have been called.	634	C<croak> have been called.
513		635
514	=item $cb = $cv->cb ([new callback])	636	=item $cb = $cv->cb ($cb->($cv))
515		637
516	This is a mutator function that returns the callback set and optionally	638	This is a mutator function that returns the callback set and optionally
517	replaces it before doing so.	639	replaces it before doing so.
518		640
519	The callback will be called when the condition becomes "true", i.e. when	641	The callback will be called when the condition becomes "true", i.e. when
520	C<send> or C<croak> are called. Calling C<recv> inside the callback	642	C<send> or C<croak> are called, with the only argument being the condition
521	or at any later time is guaranteed not to block.	643	variable itself. Calling C<recv> inside the callback or at any later time
		644	is guaranteed not to block.
522		645
523	=back	646	=back
524
525	=head3 MAINLOOP EMULATION
526
527	Sometimes (often for short test scripts, or even standalone programs
528	who only want to use AnyEvent), you I<do> want your program to block
529	indefinitely in some event loop.
530
531	In that case, you cna use a condition variable like this:
532
533	AnyEvent->condvar->recv;
534
535	This has the effect of entering the event loop and looping forever.
536
537	Note that usually your program has some exit condition, in which case
538	it is better to use the "traditional" approach of storing a condition
539	variable, waiting for it, and sending it when the program should exit
540	cleanly.
541
542		647
543	=head1 GLOBAL VARIABLES AND FUNCTIONS	648	=head1 GLOBAL VARIABLES AND FUNCTIONS
544		649
545	=over 4	650	=over 4
546		651
…		…
630		735
631	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	736	If it doesn't care, it can just "use AnyEvent" and use it itself, or not
632	do anything special (it does not need to be event-based) and let AnyEvent	737	do anything special (it does not need to be event-based) and let AnyEvent
633	decide which implementation to chose if some module relies on it.	738	decide which implementation to chose if some module relies on it.
634		739
635	If the main program relies on a specific event model. For example, in	740	If the main program relies on a specific event model - for example, in
636	Gtk2 programs you have to rely on the Glib module. You should load the	741	Gtk2 programs you have to rely on the Glib module - you should load the
637	event module before loading AnyEvent or any module that uses it: generally	742	event module before loading AnyEvent or any module that uses it: generally
638	speaking, you should load it as early as possible. The reason is that	743	speaking, you should load it as early as possible. The reason is that
639	modules might create watchers when they are loaded, and AnyEvent will	744	modules might create watchers when they are loaded, and AnyEvent will
640	decide on the event model to use as soon as it creates watchers, and it	745	decide on the event model to use as soon as it creates watchers, and it
641	might chose the wrong one unless you load the correct one yourself.	746	might chose the wrong one unless you load the correct one yourself.
642		747
643	You can chose to use a rather inefficient pure-perl implementation by	748	You can chose to use a pure-perl implementation by loading the
644	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	749	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
645	behaviour everywhere, but letting AnyEvent chose is generally better.	750	everywhere, but letting AnyEvent chose the model is generally better.
		751
		752	=head2 MAINLOOP EMULATION
		753
		754	Sometimes (often for short test scripts, or even standalone programs who
		755	only want to use AnyEvent), you do not want to run a specific event loop.
		756
		757	In that case, you can use a condition variable like this:
		758
		759	AnyEvent->condvar->recv;
		760
		761	This has the effect of entering the event loop and looping forever.
		762
		763	Note that usually your program has some exit condition, in which case
		764	it is better to use the "traditional" approach of storing a condition
		765	variable somewhere, waiting for it, and sending it when the program should
		766	exit cleanly.
		767
646		768
647	=head1 OTHER MODULES	769	=head1 OTHER MODULES
648		770
649	The following is a non-exhaustive list of additional modules that use	771	The following is a non-exhaustive list of additional modules that use
650	AnyEvent and can therefore be mixed easily with other AnyEvent modules	772	AnyEvent and can therefore be mixed easily with other AnyEvent modules
…		…
656	=item L<AnyEvent::Util>	778	=item L<AnyEvent::Util>
657		779
658	Contains various utility functions that replace often-used but blocking	780	Contains various utility functions that replace often-used but blocking
659	functions such as C<inet_aton> by event-/callback-based versions.	781	functions such as C<inet_aton> by event-/callback-based versions.
660		782
661	=item L<AnyEvent::Handle>
662
663	Provide read and write buffers and manages watchers for reads and writes.
664
665	=item L<AnyEvent::Socket>	783	=item L<AnyEvent::Socket>
666		784
667	Provides various utility functions for (internet protocol) sockets,	785	Provides various utility functions for (internet protocol) sockets,
668	addresses and name resolution. Also functions to create non-blocking tcp	786	addresses and name resolution. Also functions to create non-blocking tcp
669	connections or tcp servers, with IPv6 and SRV record support and more.	787	connections or tcp servers, with IPv6 and SRV record support and more.
670		788
		789	=item L<AnyEvent::Handle>
		790
		791	Provide read and write buffers, manages watchers for reads and writes,
		792	supports raw and formatted I/O, I/O queued and fully transparent and
		793	non-blocking SSL/TLS.
		794
		795	=item L<AnyEvent::DNS>
		796
		797	Provides rich asynchronous DNS resolver capabilities.
		798
		799	=item L<AnyEvent::HTTP>
		800
		801	A simple-to-use HTTP library that is capable of making a lot of concurrent
		802	HTTP requests.
		803
671	=item L<AnyEvent::HTTPD>	804	=item L<AnyEvent::HTTPD>
672		805
673	Provides a simple web application server framework.	806	Provides a simple web application server framework.
674		807
675	=item L<AnyEvent::DNS>
676
677	Provides rich asynchronous DNS resolver capabilities.
678
679	=item L<AnyEvent::FastPing>	808	=item L<AnyEvent::FastPing>
680		809
681	The fastest ping in the west.	810	The fastest ping in the west.
682		811
		812	=item L<AnyEvent::DBI>
		813
		814	Executes L<DBI> requests asynchronously in a proxy process.
		815
		816	=item L<AnyEvent::AIO>
		817
		818	Truly asynchronous I/O, should be in the toolbox of every event
		819	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		820	together.
		821
		822	=item L<AnyEvent::BDB>
		823
		824	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		825	L<BDB> and AnyEvent together.
		826
		827	=item L<AnyEvent::GPSD>
		828
		829	A non-blocking interface to gpsd, a daemon delivering GPS information.
		830
		831	=item L<AnyEvent::IGS>
		832
		833	A non-blocking interface to the Internet Go Server protocol (used by
		834	L<App::IGS>).
		835
683	=item L<Net::IRC3>	836	=item L<AnyEvent::IRC>
684		837
685	AnyEvent based IRC client module family.	838	AnyEvent based IRC client module family (replacing the older Net::IRC3).
686		839
687	=item L<Net::XMPP2>	840	=item L<Net::XMPP2>
688		841
689	AnyEvent based XMPP (Jabber protocol) module family.	842	AnyEvent based XMPP (Jabber protocol) module family.
690		843
…		…
699		852
700	=item L<Coro>	853	=item L<Coro>
701		854
702	Has special support for AnyEvent via L<Coro::AnyEvent>.	855	Has special support for AnyEvent via L<Coro::AnyEvent>.
703		856
704	=item L<AnyEvent::AIO>, L<IO::AIO>
705
706	Truly asynchronous I/O, should be in the toolbox of every event
707	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
708	together.
709
710	=item L<AnyEvent::BDB>, L<BDB>
711
712	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
713	IO::AIO and AnyEvent together.
714
715	=item L<IO::Lambda>	857	=item L<IO::Lambda>
716		858
717	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	859	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
718		860
719	=back	861	=back
…		…
721	=cut	863	=cut
722		864
723	package AnyEvent;	865	package AnyEvent;
724		866
725	no warnings;	867	no warnings;
726	use strict;	868	use strict qw(vars subs);
727		869
728	use Carp;	870	use Carp;
729		871
730	our $VERSION = '4.03';	872	our $VERSION = 4.341;
731	our $MODEL;	873	our $MODEL;
732		874
733	our $AUTOLOAD;	875	our $AUTOLOAD;
734	our @ISA;	876	our @ISA;
735		877
		878	our @REGISTRY;
		879
		880	our $WIN32;
		881
		882	BEGIN {
		883	my $win32 = ! ! ($^O =~ /mswin32/i);
		884	eval "sub WIN32(){ $win32 }";
		885	}
		886
736	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	887	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
737		888
738	our @REGISTRY;	889	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
739
740	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2)
741		890
742	{	891	{
743	my $idx;	892	my $idx;
744	$PROTOCOL{$_} = ++$idx	893	$PROTOCOL{$_} = ++$idx
		894	for reverse split /\s,\s/,
745	for split /\s,\s/, $ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";	895	$ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
746	}	896	}
747		897
748	my @models = (	898	my @models = (
749	[EV:: => AnyEvent::Impl::EV::],	899	[EV:: => AnyEvent::Impl::EV::],
750	[Event:: => AnyEvent::Impl::Event::],	900	[Event:: => AnyEvent::Impl::Event::],
751	[Tk:: => AnyEvent::Impl::Tk::],
752	[Wx:: => AnyEvent::Impl::POE::],
753	[Prima:: => AnyEvent::Impl::POE::],
754	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	901	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
755	# everything below here will not be autoprobed as the pureperl backend should work everywhere	902	# everything below here will not be autoprobed
756	[Glib:: => AnyEvent::Impl::Glib::],	903	# as the pureperl backend should work everywhere
		904	# and is usually faster
		905	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		906	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
757	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	907	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
758	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	908	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
759	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	909	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
		910	[Wx:: => AnyEvent::Impl::POE::],
		911	[Prima:: => AnyEvent::Impl::POE::],
760	);	912	);
761		913
762	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);	914	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
763		915
764	our @post_detect;	916	our @post_detect;
765		917
766	sub post_detect(&) {	918	sub post_detect(&) {
767	my ($cb) = @_;	919	my ($cb) = @_;
…		…
784	}	936	}
785		937
786	sub detect() {	938	sub detect() {
787	unless ($MODEL) {	939	unless ($MODEL) {
788	no strict 'refs';	940	no strict 'refs';
		941	local $SIG{__DIE__};
789		942
790	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	943	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
791	my $model = "AnyEvent::Impl::$1";	944	my $model = "AnyEvent::Impl::$1";
792	if (eval "require $model") {	945	if (eval "require $model") {
793	$MODEL = $model;	946	$MODEL = $model;
…		…
827	$MODEL	980	$MODEL
828	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	981	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
829	}	982	}
830	}	983	}
831		984
		985	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		986
832	unshift @ISA, $MODEL;	987	unshift @ISA, $MODEL;
833	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	988
		989	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
834		990
835	(shift @post_detect)->() while @post_detect;	991	(shift @post_detect)->() while @post_detect;
836	}	992	}
837		993
838	$MODEL	994	$MODEL
…		…
848		1004
849	my $class = shift;	1005	my $class = shift;
850	$class->$func (@_);	1006	$class->$func (@_);
851	}	1007	}
852		1008
		1009	# utility function to dup a filehandle. this is used by many backends
		1010	# to support binding more than one watcher per filehandle (they usually
		1011	# allow only one watcher per fd, so we dup it to get a different one).
		1012	sub _dupfh($$$$) {
		1013	my ($poll, $fh, $r, $w) = @_;
		1014
		1015	# cygwin requires the fh mode to be matching, unix doesn't
		1016	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		1017	: $poll eq "w" ? ($w, ">")
		1018	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		1019
		1020	open my $fh2, "$mode&" . fileno $fh
		1021	or die "cannot dup() filehandle: $!";
		1022
		1023	# we assume CLOEXEC is already set by perl in all important cases
		1024
		1025	($fh2, $rw)
		1026	}
		1027
853	package AnyEvent::Base;	1028	package AnyEvent::Base;
		1029
		1030	# default implementation for now and time
		1031
		1032	BEGIN {
		1033	if (eval "use Time::HiRes (); time (); 1") {
		1034	*_time = \&Time::HiRes::time;
		1035	# if (eval "use POSIX (); (POSIX::times())...
		1036	} else {
		1037	*_time = sub { time }; # epic fail
		1038	}
		1039	}
		1040
		1041	sub time { _time }
		1042	sub now { _time }
854		1043
855	# default implementation for ->condvar	1044	# default implementation for ->condvar
856		1045
857	sub condvar {	1046	sub condvar {
858	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1047	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
859	}	1048	}
860		1049
861	# default implementation for ->signal	1050	# default implementation for ->signal
862		1051
863	our %SIG_CB;	1052	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1053
		1054	sub _signal_exec {
		1055	while (%SIG_EV) {
		1056	sysread $SIGPIPE_R, my $dummy, 4;
		1057	for (keys %SIG_EV) {
		1058	delete $SIG_EV{$_};
		1059	$_->() for values %{ $SIG_CB{$_} \|\| {} };
		1060	}
		1061	}
		1062	}
864		1063
865	sub signal {	1064	sub signal {
866	my (undef, %arg) = @_;	1065	my (undef, %arg) = @_;
867		1066
		1067	unless ($SIGPIPE_R) {
		1068	if (AnyEvent::WIN32) {
		1069	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1070	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1071	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1072	} else {
		1073	pipe $SIGPIPE_R, $SIGPIPE_W;
		1074	require Fcntl;
		1075	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1076	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1077	}
		1078
		1079	$SIGPIPE_R
		1080	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1081
		1082	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1083	}
		1084
868	my $signal = uc $arg{signal}	1085	my $signal = uc $arg{signal}
869	or Carp::croak "required option 'signal' is missing";	1086	or Carp::croak "required option 'signal' is missing";
870		1087
871	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1088	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
872	$SIG{$signal} \|\|= sub {	1089	$SIG{$signal} \|\|= sub {
873	$_->() for values %{ $SIG_CB{$signal} \|\| {} };	1090	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1091	undef $SIG_EV{$signal};
874	};	1092	};
875		1093
876	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1094	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
877	}	1095	}
878		1096
879	sub AnyEvent::Base::Signal::DESTROY {	1097	sub AnyEvent::Base::Signal::DESTROY {
880	my ($signal, $cb) = @{$_[0]};	1098	my ($signal, $cb) = @{$_[0]};
881		1099
882	delete $SIG_CB{$signal}{$cb};	1100	delete $SIG_CB{$signal}{$cb};
883		1101
884	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1102	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
885	}	1103	}
886		1104
887	# default implementation for ->child	1105	# default implementation for ->child
888		1106
889	our %PID_CB;	1107	our %PID_CB;
…		…
916	or Carp::croak "required option 'pid' is missing";	1134	or Carp::croak "required option 'pid' is missing";
917		1135
918	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1136	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
919		1137
920	unless ($WNOHANG) {	1138	unless ($WNOHANG) {
921	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } \|\| 1;	1139	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
922	}	1140	}
923		1141
924	unless ($CHLD_W) {	1142	unless ($CHLD_W) {
925	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1143	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
926	# child could be a zombie already, so make at least one round	1144	# child could be a zombie already, so make at least one round
…		…
996	}	1214	}
997		1215
998	# undocumented/compatibility with pre-3.4	1216	# undocumented/compatibility with pre-3.4
999	*broadcast = \&send;	1217	*broadcast = \&send;
1000	*wait = \&_wait;	1218	*wait = \&_wait;
		1219
		1220	=head1 ERROR AND EXCEPTION HANDLING
		1221
		1222	In general, AnyEvent does not do any error handling - it relies on the
		1223	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1224	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1225	checking of all AnyEvent methods, however, which is highly useful during
		1226	development.
		1227
		1228	As for exception handling (i.e. runtime errors and exceptions thrown while
		1229	executing a callback), this is not only highly event-loop specific, but
		1230	also not in any way wrapped by this module, as this is the job of the main
		1231	program.
		1232
		1233	The pure perl event loop simply re-throws the exception (usually
		1234	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1235	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1236	so on.
		1237
		1238	=head1 ENVIRONMENT VARIABLES
		1239
		1240	The following environment variables are used by this module or its
		1241	submodules:
		1242
		1243	=over 4
		1244
		1245	=item C<PERL_ANYEVENT_VERBOSE>
		1246
		1247	By default, AnyEvent will be completely silent except in fatal
		1248	conditions. You can set this environment variable to make AnyEvent more
		1249	talkative.
		1250
		1251	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1252	conditions, such as not being able to load the event model specified by
		1253	C<PERL_ANYEVENT_MODEL>.
		1254
		1255	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1256	model it chooses.
		1257
		1258	=item C<PERL_ANYEVENT_STRICT>
		1259
		1260	AnyEvent does not do much argument checking by default, as thorough
		1261	argument checking is very costly. Setting this variable to a true value
		1262	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1263	check the arguments passed to most method calls. If it finds any problems
		1264	it will croak.
		1265
		1266	In other words, enables "strict" mode.
		1267
		1268	Unlike C<use strict>, it is definitely recommended ot keep it off in
		1269	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1270	developing programs can be very useful, however.
		1271
		1272	=item C<PERL_ANYEVENT_MODEL>
		1273
		1274	This can be used to specify the event model to be used by AnyEvent, before
		1275	auto detection and -probing kicks in. It must be a string consisting
		1276	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1277	and the resulting module name is loaded and if the load was successful,
		1278	used as event model. If it fails to load AnyEvent will proceed with
		1279	auto detection and -probing.
		1280
		1281	This functionality might change in future versions.
		1282
		1283	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1284	could start your program like this:
		1285
		1286	PERL_ANYEVENT_MODEL=Perl perl ...
		1287
		1288	=item C<PERL_ANYEVENT_PROTOCOLS>
		1289
		1290	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1291	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1292	of auto probing).
		1293
		1294	Must be set to a comma-separated list of protocols or address families,
		1295	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1296	used, and preference will be given to protocols mentioned earlier in the
		1297	list.
		1298
		1299	This variable can effectively be used for denial-of-service attacks
		1300	against local programs (e.g. when setuid), although the impact is likely
		1301	small, as the program has to handle conenction and other failures anyways.
		1302
		1303	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1304	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1305	- only support IPv4, never try to resolve or contact IPv6
		1306	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1307	IPv6, but prefer IPv6 over IPv4.
		1308
		1309	=item C<PERL_ANYEVENT_EDNS0>
		1310
		1311	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1312	for DNS. This extension is generally useful to reduce DNS traffic, but
		1313	some (broken) firewalls drop such DNS packets, which is why it is off by
		1314	default.
		1315
		1316	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1317	EDNS0 in its DNS requests.
		1318
		1319	=item C<PERL_ANYEVENT_MAX_FORKS>
		1320
		1321	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1322	will create in parallel.
		1323
		1324	=back
1001		1325
1002	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1326	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1003		1327
1004	This is an advanced topic that you do not normally need to use AnyEvent in	1328	This is an advanced topic that you do not normally need to use AnyEvent in
1005	a module. This section is only of use to event loop authors who want to	1329	a module. This section is only of use to event loop authors who want to
…		…
1039		1363
1040	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1364	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1041	condition variables: code blocking while waiting for a condition will	1365	condition variables: code blocking while waiting for a condition will
1042	C<die>. This still works with most modules/usages, and blocking calls must	1366	C<die>. This still works with most modules/usages, and blocking calls must
1043	not be done in an interactive application, so it makes sense.	1367	not be done in an interactive application, so it makes sense.
1044
1045	=head1 ENVIRONMENT VARIABLES
1046
1047	The following environment variables are used by this module:
1048
1049	=over 4
1050
1051	=item C<PERL_ANYEVENT_VERBOSE>
1052
1053	By default, AnyEvent will be completely silent except in fatal
1054	conditions. You can set this environment variable to make AnyEvent more
1055	talkative.
1056
1057	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1058	conditions, such as not being able to load the event model specified by
1059	C<PERL_ANYEVENT_MODEL>.
1060
1061	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1062	model it chooses.
1063
1064	=item C<PERL_ANYEVENT_MODEL>
1065
1066	This can be used to specify the event model to be used by AnyEvent, before
1067	auto detection and -probing kicks in. It must be a string consisting
1068	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1069	and the resulting module name is loaded and if the load was successful,
1070	used as event model. If it fails to load AnyEvent will proceed with
1071	auto detection and -probing.
1072
1073	This functionality might change in future versions.
1074
1075	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1076	could start your program like this:
1077
1078	PERL_ANYEVENT_MODEL=Perl perl ...
1079
1080	=item C<PERL_ANYEVENT_PROTOCOLS>
1081
1082	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1083	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1084	of auto probing).
1085
1086	Must be set to a comma-separated list of protocols or address families,
1087	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1088	used, and preference will be given to protocols mentioned earlier in the
1089	list.
1090
1091	This variable can effectively be used for denial-of-service attacks
1092	against local programs (e.g. when setuid), although the impact is likely
1093	small, as the program has to handle connection errors already-
1094
1095	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1096	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1097	- only support IPv4, never try to resolve or contact IPv6
1098	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1099	IPv6, but prefer IPv6 over IPv4.
1100
1101	=item C<PERL_ANYEVENT_EDNS0>
1102
1103	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1104	for DNS. This extension is generally useful to reduce DNS traffic, but
1105	some (broken) firewalls drop such DNS packets, which is why it is off by
1106	default.
1107
1108	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1109	EDNS0 in its DNS requests.
1110
1111	=back
1112		1368
1113	=head1 EXAMPLE PROGRAM	1369	=head1 EXAMPLE PROGRAM
1114		1370
1115	The following program uses an I/O watcher to read data from STDIN, a timer	1371	The following program uses an I/O watcher to read data from STDIN, a timer
1116	to display a message once per second, and a condition variable to quit the	1372	to display a message once per second, and a condition variable to quit the
…		…
1310	watcher.	1566	watcher.
1311		1567
1312	=head3 Results	1568	=head3 Results
1313		1569
1314	name watchers bytes create invoke destroy comment	1570	name watchers bytes create invoke destroy comment
1315	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1571	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1316	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1572	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1317	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1573	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1318	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1574	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1319	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1575	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1320	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	1576	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1321	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1577	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1322	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1578	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1323	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1579	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1324	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1580	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1325		1581
1326	=head3 Discussion	1582	=head3 Discussion
1327		1583
1328	The benchmark does I<not> measure scalability of the event loop very	1584	The benchmark does I<not> measure scalability of the event loop very
1329	well. For example, a select-based event loop (such as the pure perl one)	1585	well. For example, a select-based event loop (such as the pure perl one)
…		…
1531	watchers, as the management overhead dominates.	1787	watchers, as the management overhead dominates.
1532		1788
1533	=back	1789	=back
1534		1790
1535		1791
		1792	=head1 SIGNALS
		1793
		1794	AnyEvent currently installs handlers for these signals:
		1795
		1796	=over 4
		1797
		1798	=item SIGCHLD
		1799
		1800	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		1801	emulation for event loops that do not support them natively. Also, some
		1802	event loops install a similar handler.
		1803
		1804	=item SIGPIPE
		1805
		1806	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		1807	when AnyEvent gets loaded.
		1808
		1809	The rationale for this is that AnyEvent users usually do not really depend
		1810	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		1811	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		1812	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		1813	some random socket.
		1814
		1815	The rationale for installing a no-op handler as opposed to ignoring it is
		1816	that this way, the handler will be restored to defaults on exec.
		1817
		1818	Feel free to install your own handler, or reset it to defaults.
		1819
		1820	=back
		1821
		1822	=cut
		1823
		1824	$SIG{PIPE} = sub { }
		1825	unless defined $SIG{PIPE};
		1826
		1827
1536	=head1 FORK	1828	=head1 FORK
1537		1829
1538	Most event libraries are not fork-safe. The ones who are usually are	1830	Most event libraries are not fork-safe. The ones who are usually are
1539	because they rely on inefficient but fork-safe C<select> or C<poll>	1831	because they rely on inefficient but fork-safe C<select> or C<poll>
1540	calls. Only L<EV> is fully fork-aware.	1832	calls. Only L<EV> is fully fork-aware.
…		…
1553	specified in the variable.	1845	specified in the variable.
1554		1846
1555	You can make AnyEvent completely ignore this variable by deleting it	1847	You can make AnyEvent completely ignore this variable by deleting it
1556	before the first watcher gets created, e.g. with a C<BEGIN> block:	1848	before the first watcher gets created, e.g. with a C<BEGIN> block:
1557		1849
1558	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1850	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1559		1851
1560	use AnyEvent;	1852	use AnyEvent;
1561		1853
1562	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1854	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1563	be used to probe what backend is used and gain other information (which is	1855	be used to probe what backend is used and gain other information (which is
1564	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	1856	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1857	$ENV{PERL_ANYEGENT_STRICT}.
		1858
		1859
		1860	=head1 BUGS
		1861
		1862	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		1863	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		1864	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		1865	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as
		1866	pronounced).
1565		1867
1566		1868
1567	=head1 SEE ALSO	1869	=head1 SEE ALSO
1568		1870
1569	Utility functions: L<AnyEvent::Util>.	1871	Utility functions: L<AnyEvent::Util>.
…		…
1586	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	1888	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1587		1889
1588		1890
1589	=head1 AUTHOR	1891	=head1 AUTHOR
1590		1892
1591	Marc Lehmann <schmorp@schmorp.de>	1893	Marc Lehmann <schmorp@schmorp.de>
1592	http://home.schmorp.de/	1894	http://home.schmorp.de/
1593		1895
1594	=cut	1896	=cut
1595		1897
1596	1	1898	1
1597		1899

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.133 by root, Sun May 25 03:44:03 2008 UTC vs. Revision 1.196 by root, Thu Mar 26 07:47:42 2009 UTC

Diff Legend

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.133 by root, Sun May 25 03:44:03 2008 UTC vs.
Revision 1.196 by root, Thu Mar 26 07:47:42 2009 UTC