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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.127 by root, Sat May 24 01:15:19 2008 UTC vs.
Revision 1.173 by root, Mon Jul 21 03:47:22 2008 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 enourmous 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
113	the callback to call, the filehandle to watch, etc.	135	the callback to call, the file handle to watch, etc.
114		136
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).
…		…
126	Many watchers either are used with "recursion" (repeating timers for	148	Many watchers either are used with "recursion" (repeating timers for
127	example), or need to refer to their watcher object in other ways.	149	example), or need to refer to their watcher object in other ways.
128		150
129	An any way to achieve that is this pattern:	151	An any way to achieve that is this pattern:
130		152
131	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	153	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
132	# you can use $w here, for example to undef it	154	# you can use $w here, for example to undef it
133	undef $w;	155	undef $w;
134	});	156	});
135		157
136	Note that C<my $w; $w => combination. This is necessary because in Perl,	158	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	159	my variables are only visible after the statement in which they are
138	declared.	160	declared.
139		161
140	=head2 I/O WATCHERS	162	=head2 I/O WATCHERS
141		163
142	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	164	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
143	with the following mandatory key-value pairs as arguments:	165	with the following mandatory key-value pairs as arguments:
144		166
145	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	167	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events
146	for events. C<poll> must be a string that is either C<r> or C<w>,	168	(AnyEvent might or might not keep a reference to this file handle). C<poll>
147	which creates a watcher waiting for "r"eadable or "w"ritable events,	169	must be a string that is either C<r> or C<w>, which creates a watcher
148	respectively. C<cb> is the callback to invoke each time the file handle	170	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the
149	becomes ready.	171	callback to invoke each time the file handle becomes ready.
150		172
151	Although the callback might get passed parameters, their value and	173	Although the callback might get passed parameters, their value and
152	presence is undefined and you cannot rely on them. Portable AnyEvent	174	presence is undefined and you cannot rely on them. Portable AnyEvent
153	callbacks cannot use arguments passed to I/O watcher callbacks.	175	callbacks cannot use arguments passed to I/O watcher callbacks.
154		176
…		…
158		180
159	Some event loops issue spurious readyness notifications, so you should	181	Some event loops issue spurious readyness notifications, so you should
160	always use non-blocking calls when reading/writing from/to your file	182	always use non-blocking calls when reading/writing from/to your file
161	handles.	183	handles.
162		184
163	Example:
164
165	# wait for readability of STDIN, then read a line and disable the watcher	185	Example: wait for readability of STDIN, then read a line and disable the
		186	watcher.
		187
166	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	188	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
167	chomp (my $input = <STDIN>);	189	chomp (my $input = <STDIN>);
168	warn "read: $input\n";	190	warn "read: $input\n";
169	undef $w;	191	undef $w;
170	});	192	});
…		…
180		202
181	Although the callback might get passed parameters, their value and	203	Although the callback might get passed parameters, their value and
182	presence is undefined and you cannot rely on them. Portable AnyEvent	204	presence is undefined and you cannot rely on them. Portable AnyEvent
183	callbacks cannot use arguments passed to time watcher callbacks.	205	callbacks cannot use arguments passed to time watcher callbacks.
184		206
185	The timer callback will be invoked at most once: if you want a repeating	207	The callback will normally be invoked once only. If you specify another
186	timer you have to create a new watcher (this is a limitation by both Tk	208	parameter, C<interval>, as a strictly positive number (> 0), then the
187	and Glib).	209	callback will be invoked regularly at that interval (in fractional
		210	seconds) after the first invocation. If C<interval> is specified with a
		211	false value, then it is treated as if it were missing.
188		212
189	Example:	213	The callback will be rescheduled before invoking the callback, but no
		214	attempt is done to avoid timer drift in most backends, so the interval is
		215	only approximate.
190		216
191	# fire an event after 7.7 seconds	217	Example: fire an event after 7.7 seconds.
		218
192	my $w = AnyEvent->timer (after => 7.7, cb => sub {	219	my $w = AnyEvent->timer (after => 7.7, cb => sub {
193	warn "timeout\n";	220	warn "timeout\n";
194	});	221	});
195		222
196	# to cancel the timer:	223	# to cancel the timer:
197	undef $w;	224	undef $w;
198		225
199	Example 2:
200
201	# fire an event after 0.5 seconds, then roughly every second	226	Example 2: fire an event after 0.5 seconds, then roughly every second.
202	my $w;
203		227
204	my $cb = sub {
205	# cancel the old timer while creating a new one
206	$w = AnyEvent->timer (after => 1, cb => $cb);	228	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		229	warn "timeout\n";
207	};	230	};
208
209	# start the "loop" by creating the first watcher
210	$w = AnyEvent->timer (after => 0.5, cb => $cb);
211		231
212	=head3 TIMING ISSUES	232	=head3 TIMING ISSUES
213		233
214	There are two ways to handle timers: based on real time (relative, "fire	234	There are two ways to handle timers: based on real time (relative, "fire
215	in 10 seconds") and based on wallclock time (absolute, "fire at 12	235	in 10 seconds") and based on wallclock time (absolute, "fire at 12
…		…
227	timers.	247	timers.
228		248
229	AnyEvent always prefers relative timers, if available, matching the	249	AnyEvent always prefers relative timers, if available, matching the
230	AnyEvent API.	250	AnyEvent API.
231		251
		252	AnyEvent has two additional methods that return the "current time":
		253
		254	=over 4
		255
		256	=item AnyEvent->time
		257
		258	This returns the "current wallclock time" as a fractional number of
		259	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
		260	return, and the result is guaranteed to be compatible with those).
		261
		262	It progresses independently of any event loop processing, i.e. each call
		263	will check the system clock, which usually gets updated frequently.
		264
		265	=item AnyEvent->now
		266
		267	This also returns the "current wallclock time", but unlike C<time>, above,
		268	this value might change only once per event loop iteration, depending on
		269	the event loop (most return the same time as C<time>, above). This is the
		270	time that AnyEvent's timers get scheduled against.
		271
		272	I<In almost all cases (in all cases if you don't care), this is the
		273	function to call when you want to know the current time.>
		274
		275	This function is also often faster then C<< AnyEvent->time >>, and
		276	thus the preferred method if you want some timestamp (for example,
		277	L<AnyEvent::Handle> uses this to update it's activity timeouts).
		278
		279	The rest of this section is only of relevance if you try to be very exact
		280	with your timing, you can skip it without bad conscience.
		281
		282	For a practical example of when these times differ, consider L<Event::Lib>
		283	and L<EV> and the following set-up:
		284
		285	The event loop is running and has just invoked one of your callback at
		286	time=500 (assume no other callbacks delay processing). In your callback,
		287	you wait a second by executing C<sleep 1> (blocking the process for a
		288	second) and then (at time=501) you create a relative timer that fires
		289	after three seconds.
		290
		291	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
		292	both return C<501>, because that is the current time, and the timer will
		293	be scheduled to fire at time=504 (C<501> + C<3>).
		294
		295	With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
		296	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
		297	last event processing phase started. With L<EV>, your timer gets scheduled
		298	to run at time=503 (C<500> + C<3>).
		299
		300	In one sense, L<Event::Lib> is more exact, as it uses the current time
		301	regardless of any delays introduced by event processing. However, most
		302	callbacks do not expect large delays in processing, so this causes a
		303	higher drift (and a lot more system calls to get the current time).
		304
		305	In another sense, L<EV> is more exact, as your timer will be scheduled at
		306	the same time, regardless of how long event processing actually took.
		307
		308	In either case, if you care (and in most cases, you don't), then you
		309	can get whatever behaviour you want with any event loop, by taking the
		310	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
		311	account.
		312
		313	=back
		314
232	=head2 SIGNAL WATCHERS	315	=head2 SIGNAL WATCHERS
233		316
234	You can watch for signals using a signal watcher, C<signal> is the signal	317	You can watch for signals using a signal watcher, C<signal> is the signal
235	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to	318	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
236	be invoked whenever a signal occurs.	319	callback to be invoked whenever a signal occurs.
237		320
238	Although the callback might get passed parameters, their value and	321	Although the callback might get passed parameters, their value and
239	presence is undefined and you cannot rely on them. Portable AnyEvent	322	presence is undefined and you cannot rely on them. Portable AnyEvent
240	callbacks cannot use arguments passed to signal watcher callbacks.	323	callbacks cannot use arguments passed to signal watcher callbacks.
241		324
242	Multiple signal occurances can be clumped together into one callback	325	Multiple signal occurrences can be clumped together into one callback
243	invocation, and callback invocation will be synchronous. synchronous means	326	invocation, and callback invocation will be synchronous. Synchronous means
244	that it might take a while until the signal gets handled by the process,	327	that it might take a while until the signal gets handled by the process,
245	but it is guarenteed not to interrupt any other callbacks.	328	but it is guaranteed not to interrupt any other callbacks.
246		329
247	The main advantage of using these watchers is that you can share a signal	330	The main advantage of using these watchers is that you can share a signal
248	between multiple watchers.	331	between multiple watchers.
249		332
250	This watcher might use C<%SIG>, so programs overwriting those signals	333	This watcher might use C<%SIG>, so programs overwriting those signals
…		…
277	AnyEvent program, you I<have> to create at least one watcher before you	360	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>).	361	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
279		362
280	Example: fork a process and wait for it	363	Example: fork a process and wait for it
281		364
282	my $done = AnyEvent->condvar;	365	my $done = AnyEvent->condvar;
283		366
284	my $pid = fork or exit 5;	367	my $pid = fork or exit 5;
285		368
286	my $w = AnyEvent->child (	369	my $w = AnyEvent->child (
287	pid => $pid,	370	pid => $pid,
288	cb => sub {	371	cb => sub {
289	my ($pid, $status) = @_;	372	my ($pid, $status) = @_;
290	warn "pid $pid exited with status $status";	373	warn "pid $pid exited with status $status";
291	$done->send;	374	$done->send;
292	},	375	},
293	);	376	);
294		377
295	# do something else, then wait for process exit	378	# do something else, then wait for process exit
296	$done->recv;	379	$done->recv;
297		380
298	=head2 CONDITION VARIABLES	381	=head2 CONDITION VARIABLES
299		382
300	If you are familiar with some event loops you will know that all of them	383	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	384	require you to run some blocking "loop", "run" or similar function that
…		…
306		389
307	The instrument to do that is called a "condition variable", so called	390	The instrument to do that is called a "condition variable", so called
308	because they represent a condition that must become true.	391	because they represent a condition that must become true.
309		392
310	Condition variables can be created by calling the C<< AnyEvent->condvar	393	Condition variables can be created by calling the C<< AnyEvent->condvar
		394
311	>> method, usually without arguments. The only argument pair allowed is	395	>> method, usually without arguments. The only argument pair allowed is
		396
312	C<cb>, which specifies a callback to be called when the condition variable	397	C<cb>, which specifies a callback to be called when the condition variable
313	becomes true.	398	becomes true, with the condition variable as the first argument (but not
		399	the results).
314		400
315	After creation, the conditon variable is "false" until it becomes "true"	401	After creation, the condition variable is "false" until it becomes "true"
316	by calling the C<send> method.	402	by calling the C<send> method (or calling the condition variable as if it
		403	were a callback, read about the caveats in the description for the C<<
		404	->send >> method).
317		405
318	Condition variables are similar to callbacks, except that you can	406	Condition variables are similar to callbacks, except that you can
319	optionally wait for them. They can also be called merge points - points	407	optionally wait for them. They can also be called merge points - points
320	in time where multiple outstandign events have been processed. And yet	408	in time where multiple outstanding events have been processed. And yet
321	another way to call them is transations - each condition variable can be	409	another way to call them is transactions - each condition variable can be
322	used to represent a transaction, which finishes at some point and delivers	410	used to represent a transaction, which finishes at some point and delivers
323	a result.	411	a result.
324		412
325	Condition variables are very useful to signal that something has finished,	413	Condition variables are very useful to signal that something has finished,
326	for example, if you write a module that does asynchronous http requests,	414	for example, if you write a module that does asynchronous http requests,
…		…
332	you can block your main program until an event occurs - for example, you	420	you can block your main program until an event occurs - for example, you
333	could C<< ->recv >> in your main program until the user clicks the Quit	421	could C<< ->recv >> in your main program until the user clicks the Quit
334	button of your app, which would C<< ->send >> the "quit" event.	422	button of your app, which would C<< ->send >> the "quit" event.
335		423
336	Note that condition variables recurse into the event loop - if you have	424	Note that condition variables recurse into the event loop - if you have
337	two pieces of code that call C<< ->recv >> in a round-robbin fashion, you	425	two pieces of code that call C<< ->recv >> in a round-robin fashion, you
338	lose. Therefore, condition variables are good to export to your caller, but	426	lose. Therefore, condition variables are good to export to your caller, but
339	you should avoid making a blocking wait yourself, at least in callbacks,	427	you should avoid making a blocking wait yourself, at least in callbacks,
340	as this asks for trouble.	428	as this asks for trouble.
341		429
342	Condition variables are represented by hash refs in perl, and the keys	430	Condition variables are represented by hash refs in perl, and the keys
…		…
347		435
348	There are two "sides" to a condition variable - the "producer side" which	436	There are two "sides" to a condition variable - the "producer side" which
349	eventually calls C<< -> send >>, and the "consumer side", which waits	437	eventually calls C<< -> send >>, and the "consumer side", which waits
350	for the send to occur.	438	for the send to occur.
351		439
352	Example:	440	Example: wait for a timer.
353		441
354	# wait till the result is ready	442	# wait till the result is ready
355	my $result_ready = AnyEvent->condvar;	443	my $result_ready = AnyEvent->condvar;
356		444
357	# do something such as adding a timer	445	# do something such as adding a timer
…		…
365		453
366	# this "blocks" (while handling events) till the callback	454	# this "blocks" (while handling events) till the callback
367	# calls send	455	# calls send
368	$result_ready->recv;	456	$result_ready->recv;
369		457
		458	Example: wait for a timer, but take advantage of the fact that
		459	condition variables are also code references.
		460
		461	my $done = AnyEvent->condvar;
		462	my $delay = AnyEvent->timer (after => 5, cb => $done);
		463	$done->recv;
		464
		465	Example: Imagine an API that returns a condvar and doesn't support
		466	callbacks. This is how you make a synchronous call, for example from
		467	the main program:
		468
		469	use AnyEvent::CouchDB;
		470
		471	...
		472
		473	my @info = $couchdb->info->recv;
		474
		475	And this is how you would just ste a callback to be called whenever the
		476	results are available:
		477
		478	$couchdb->info->cb (sub {
		479	my @info = $_[0]->recv;
		480	});
		481
370	=head3 METHODS FOR PRODUCERS	482	=head3 METHODS FOR PRODUCERS
371		483
372	These methods should only be used by the producing side, i.e. the	484	These methods should only be used by the producing side, i.e. the
373	code/module that eventually sends the signal. Note that it is also	485	code/module that eventually sends the signal. Note that it is also
374	the producer side which creates the condvar in most cases, but it isn't	486	the producer side which creates the condvar in most cases, but it isn't
…		…
385	If a callback has been set on the condition variable, it is called	497	If a callback has been set on the condition variable, it is called
386	immediately from within send.	498	immediately from within send.
387		499
388	Any arguments passed to the C<send> call will be returned by all	500	Any arguments passed to the C<send> call will be returned by all
389	future C<< ->recv >> calls.	501	future C<< ->recv >> calls.
		502
		503	Condition variables are overloaded so one can call them directly
		504	(as a code reference). Calling them directly is the same as calling
		505	C<send>. Note, however, that many C-based event loops do not handle
		506	overloading, so as tempting as it may be, passing a condition variable
		507	instead of a callback does not work. Both the pure perl and EV loops
		508	support overloading, however, as well as all functions that use perl to
		509	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
		510	example).
390		511
391	=item $cv->croak ($error)	512	=item $cv->croak ($error)
392		513
393	Similar to send, but causes all call's to C<< ->recv >> to invoke	514	Similar to send, but causes all call's to C<< ->recv >> to invoke
394	C<Carp::croak> with the given error message/object/scalar.	515	C<Carp::croak> with the given error message/object/scalar.
…		…
443	doesn't execute once).	564	doesn't execute once).
444		565
445	This is the general pattern when you "fan out" into multiple subrequests:	566	This is the general pattern when you "fan out" into multiple subrequests:
446	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	567	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>
447	is called at least once, and then, for each subrequest you start, call	568	is called at least once, and then, for each subrequest you start, call
448	C<begin> and for eahc subrequest you finish, call C<end>.	569	C<begin> and for each subrequest you finish, call C<end>.
449		570
450	=back	571	=back
451		572
452	=head3 METHODS FOR CONSUMERS	573	=head3 METHODS FOR CONSUMERS
453		574
…		…
475	(programs might want to do that to stay interactive), so I<if you are	596	(programs might want to do that to stay interactive), so I<if you are
476	using this from a module, never require a blocking wait>, but let the	597	using this from a module, never require a blocking wait>, but let the
477	caller decide whether the call will block or not (for example, by coupling	598	caller decide whether the call will block or not (for example, by coupling
478	condition variables with some kind of request results and supporting	599	condition variables with some kind of request results and supporting
479	callbacks so the caller knows that getting the result will not block,	600	callbacks so the caller knows that getting the result will not block,
480	while still suppporting blocking waits if the caller so desires).	601	while still supporting blocking waits if the caller so desires).
481		602
482	Another reason I<never> to C<< ->recv >> in a module is that you cannot	603	Another reason I<never> to C<< ->recv >> in a module is that you cannot
483	sensibly have two C<< ->recv >>'s in parallel, as that would require	604	sensibly have two C<< ->recv >>'s in parallel, as that would require
484	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	605	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
485	can supply.	606	can supply.
…		…
498	=item $bool = $cv->ready	619	=item $bool = $cv->ready
499		620
500	Returns true when the condition is "true", i.e. whether C<send> or	621	Returns true when the condition is "true", i.e. whether C<send> or
501	C<croak> have been called.	622	C<croak> have been called.
502		623
503	=item $cb = $cv->cb ([new callback])	624	=item $cb = $cv->cb ($cb->($cv))
504		625
505	This is a mutator function that returns the callback set and optionally	626	This is a mutator function that returns the callback set and optionally
506	replaces it before doing so.	627	replaces it before doing so.
507		628
508	The callback will be called when the condition becomes "true", i.e. when	629	The callback will be called when the condition becomes "true", i.e. when
509	C<send> or C<croak> are called. Calling C<recv> inside the callback	630	C<send> or C<croak> are called, with the only argument being the condition
510	or at any later time is guaranteed not to block.	631	variable itself. Calling C<recv> inside the callback or at any later time
		632	is guaranteed not to block.
511		633
512	=back	634	=back
513		635
514	=head1 GLOBAL VARIABLES AND FUNCTIONS	636	=head1 GLOBAL VARIABLES AND FUNCTIONS
515		637
…		…
601		723
602	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	724	If it doesn't care, it can just "use AnyEvent" and use it itself, or not
603	do anything special (it does not need to be event-based) and let AnyEvent	725	do anything special (it does not need to be event-based) and let AnyEvent
604	decide which implementation to chose if some module relies on it.	726	decide which implementation to chose if some module relies on it.
605		727
606	If the main program relies on a specific event model. For example, in	728	If the main program relies on a specific event model - for example, in
607	Gtk2 programs you have to rely on the Glib module. You should load the	729	Gtk2 programs you have to rely on the Glib module - you should load the
608	event module before loading AnyEvent or any module that uses it: generally	730	event module before loading AnyEvent or any module that uses it: generally
609	speaking, you should load it as early as possible. The reason is that	731	speaking, you should load it as early as possible. The reason is that
610	modules might create watchers when they are loaded, and AnyEvent will	732	modules might create watchers when they are loaded, and AnyEvent will
611	decide on the event model to use as soon as it creates watchers, and it	733	decide on the event model to use as soon as it creates watchers, and it
612	might chose the wrong one unless you load the correct one yourself.	734	might chose the wrong one unless you load the correct one yourself.
613		735
614	You can chose to use a rather inefficient pure-perl implementation by	736	You can chose to use a pure-perl implementation by loading the
615	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	737	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
616	behaviour everywhere, but letting AnyEvent chose is generally better.	738	everywhere, but letting AnyEvent chose the model is generally better.
		739
		740	=head2 MAINLOOP EMULATION
		741
		742	Sometimes (often for short test scripts, or even standalone programs who
		743	only want to use AnyEvent), you do not want to run a specific event loop.
		744
		745	In that case, you can use a condition variable like this:
		746
		747	AnyEvent->condvar->recv;
		748
		749	This has the effect of entering the event loop and looping forever.
		750
		751	Note that usually your program has some exit condition, in which case
		752	it is better to use the "traditional" approach of storing a condition
		753	variable somewhere, waiting for it, and sending it when the program should
		754	exit cleanly.
		755
617		756
618	=head1 OTHER MODULES	757	=head1 OTHER MODULES
619		758
620	The following is a non-exhaustive list of additional modules that use	759	The following is a non-exhaustive list of additional modules that use
621	AnyEvent and can therefore be mixed easily with other AnyEvent modules	760	AnyEvent and can therefore be mixed easily with other AnyEvent modules
…		…
627	=item L<AnyEvent::Util>	766	=item L<AnyEvent::Util>
628		767
629	Contains various utility functions that replace often-used but blocking	768	Contains various utility functions that replace often-used but blocking
630	functions such as C<inet_aton> by event-/callback-based versions.	769	functions such as C<inet_aton> by event-/callback-based versions.
631		770
632	=item L<AnyEvent::Handle>
633
634	Provide read and write buffers and manages watchers for reads and writes.
635
636	=item L<AnyEvent::Socket>	771	=item L<AnyEvent::Socket>
637		772
638	Provides various utility functions for (internet protocol) sockets,	773	Provides various utility functions for (internet protocol) sockets,
639	addresses and name resolution. Also functions to create non-blocking tcp	774	addresses and name resolution. Also functions to create non-blocking tcp
640	connections or tcp servers, with IPv6 and SRV record support and more.	775	connections or tcp servers, with IPv6 and SRV record support and more.
641		776
		777	=item L<AnyEvent::Handle>
		778
		779	Provide read and write buffers, manages watchers for reads and writes,
		780	supports raw and formatted I/O, I/O queued and fully transparent and
		781	non-blocking SSL/TLS.
		782
		783	=item L<AnyEvent::DNS>
		784
		785	Provides rich asynchronous DNS resolver capabilities.
		786
		787	=item L<AnyEvent::HTTP>
		788
		789	A simple-to-use HTTP library that is capable of making a lot of concurrent
		790	HTTP requests.
		791
642	=item L<AnyEvent::HTTPD>	792	=item L<AnyEvent::HTTPD>
643		793
644	Provides a simple web application server framework.	794	Provides a simple web application server framework.
645		795
646	=item L<AnyEvent::DNS>
647
648	Provides rich asynchronous DNS resolver capabilities.
649
650	=item L<AnyEvent::FastPing>	796	=item L<AnyEvent::FastPing>
651		797
652	The fastest ping in the west.	798	The fastest ping in the west.
		799
		800	=item L<AnyEvent::DBI>
		801
		802	Executes L<DBI> requests asynchronously in a proxy process.
		803
		804	=item L<AnyEvent::AIO>
		805
		806	Truly asynchronous I/O, should be in the toolbox of every event
		807	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		808	together.
		809
		810	=item L<AnyEvent::BDB>
		811
		812	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		813	L<BDB> and AnyEvent together.
		814
		815	=item L<AnyEvent::GPSD>
		816
		817	A non-blocking interface to gpsd, a daemon delivering GPS information.
		818
		819	=item L<AnyEvent::IGS>
		820
		821	A non-blocking interface to the Internet Go Server protocol (used by
		822	L<App::IGS>).
653		823
654	=item L<Net::IRC3>	824	=item L<Net::IRC3>
655		825
656	AnyEvent based IRC client module family.	826	AnyEvent based IRC client module family.
657		827
…		…
670		840
671	=item L<Coro>	841	=item L<Coro>
672		842
673	Has special support for AnyEvent via L<Coro::AnyEvent>.	843	Has special support for AnyEvent via L<Coro::AnyEvent>.
674		844
675	=item L<AnyEvent::AIO>, L<IO::AIO>
676
677	Truly asynchronous I/O, should be in the toolbox of every event
678	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
679	together.
680
681	=item L<AnyEvent::BDB>, L<BDB>
682
683	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
684	IO::AIO and AnyEvent together.
685
686	=item L<IO::Lambda>	845	=item L<IO::Lambda>
687		846
688	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	847	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
689		848
690	=back	849	=back
…		…
696	no warnings;	855	no warnings;
697	use strict;	856	use strict;
698		857
699	use Carp;	858	use Carp;
700		859
701	our $VERSION = '3.6';	860	our $VERSION = 4.22;
702	our $MODEL;	861	our $MODEL;
703		862
704	our $AUTOLOAD;	863	our $AUTOLOAD;
705	our @ISA;	864	our @ISA;
706		865
		866	our @REGISTRY;
		867
		868	our $WIN32;
		869
		870	BEGIN {
		871	my $win32 = ! ! ($^O =~ /mswin32/i);
		872	eval "sub WIN32(){ $win32 }";
		873	}
		874
707	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	875	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
708		876
709	our @REGISTRY;	877	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
710
711	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2)
712		878
713	{	879	{
714	my $idx;	880	my $idx;
715	$PROTOCOL{$_} = ++$idx	881	$PROTOCOL{$_} = ++$idx
		882	for reverse split /\s,\s/,
716	for split /\s,\s/, $ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";	883	$ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
717	}	884	}
718		885
719	my @models = (	886	my @models = (
720	[EV:: => AnyEvent::Impl::EV::],	887	[EV:: => AnyEvent::Impl::EV::],
721	[Event:: => AnyEvent::Impl::Event::],	888	[Event:: => AnyEvent::Impl::Event::],
722	[Tk:: => AnyEvent::Impl::Tk::],
723	[Wx:: => AnyEvent::Impl::POE::],
724	[Prima:: => AnyEvent::Impl::POE::],
725	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	889	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
726	# everything below here will not be autoprobed as the pureperl backend should work everywhere	890	# everything below here will not be autoprobed
727	[Glib:: => AnyEvent::Impl::Glib::],	891	# as the pureperl backend should work everywhere
		892	# and is usually faster
		893	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		894	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
728	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	895	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
729	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	896	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
730	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	897	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
		898	[Wx:: => AnyEvent::Impl::POE::],
		899	[Prima:: => AnyEvent::Impl::POE::],
731	);	900	);
732		901
733	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);	902	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
734		903
735	our @post_detect;	904	our @post_detect;
736		905
737	sub post_detect(&) {	906	sub post_detect(&) {
738	my ($cb) = @_;	907	my ($cb) = @_;
…		…
755	}	924	}
756		925
757	sub detect() {	926	sub detect() {
758	unless ($MODEL) {	927	unless ($MODEL) {
759	no strict 'refs';	928	no strict 'refs';
		929	local $SIG{__DIE__};
760		930
761	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	931	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
762	my $model = "AnyEvent::Impl::$1";	932	my $model = "AnyEvent::Impl::$1";
763	if (eval "require $model") {	933	if (eval "require $model") {
764	$MODEL = $model;	934	$MODEL = $model;
…		…
798	$MODEL	968	$MODEL
799	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	969	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
800	}	970	}
801	}	971	}
802		972
		973	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		974
803	unshift @ISA, $MODEL;	975	unshift @ISA, $MODEL;
804	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	976
		977	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
805		978
806	(shift @post_detect)->() while @post_detect;	979	(shift @post_detect)->() while @post_detect;
807	}	980	}
808		981
809	$MODEL	982	$MODEL
…		…
819		992
820	my $class = shift;	993	my $class = shift;
821	$class->$func (@_);	994	$class->$func (@_);
822	}	995	}
823		996
		997	# utility function to dup a filehandle. this is used by many backends
		998	# to support binding more than one watcher per filehandle (they usually
		999	# allow only one watcher per fd, so we dup it to get a different one).
		1000	sub _dupfh($$$$) {
		1001	my ($poll, $fh, $r, $w) = @_;
		1002
		1003	require Fcntl;
		1004
		1005	# cygwin requires the fh mode to be matching, unix doesn't
		1006	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		1007	: $poll eq "w" ? ($w, ">")
		1008	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		1009
		1010	open my $fh2, "$mode&" . fileno $fh
		1011	or die "cannot dup() filehandle: $!";
		1012
		1013	# we assume CLOEXEC is already set by perl in all important cases
		1014
		1015	($fh2, $rw)
		1016	}
		1017
824	package AnyEvent::Base;	1018	package AnyEvent::Base;
		1019
		1020	# default implementation for now and time
		1021
		1022	use Time::HiRes ();
		1023
		1024	sub time { Time::HiRes::time }
		1025	sub now { Time::HiRes::time }
825		1026
826	# default implementation for ->condvar	1027	# default implementation for ->condvar
827		1028
828	sub condvar {	1029	sub condvar {
829	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1030	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
…		…
850	sub AnyEvent::Base::Signal::DESTROY {	1051	sub AnyEvent::Base::Signal::DESTROY {
851	my ($signal, $cb) = @{$_[0]};	1052	my ($signal, $cb) = @{$_[0]};
852		1053
853	delete $SIG_CB{$signal}{$cb};	1054	delete $SIG_CB{$signal}{$cb};
854		1055
855	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1056	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
856	}	1057	}
857		1058
858	# default implementation for ->child	1059	# default implementation for ->child
859		1060
860	our %PID_CB;	1061	our %PID_CB;
…		…
887	or Carp::croak "required option 'pid' is missing";	1088	or Carp::croak "required option 'pid' is missing";
888		1089
889	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1090	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
890		1091
891	unless ($WNOHANG) {	1092	unless ($WNOHANG) {
892	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } \|\| 1;	1093	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
893	}	1094	}
894		1095
895	unless ($CHLD_W) {	1096	unless ($CHLD_W) {
896	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1097	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
897	# child could be a zombie already, so make at least one round	1098	# child could be a zombie already, so make at least one round
…		…
913	package AnyEvent::CondVar;	1114	package AnyEvent::CondVar;
914		1115
915	our @ISA = AnyEvent::CondVar::Base::;	1116	our @ISA = AnyEvent::CondVar::Base::;
916		1117
917	package AnyEvent::CondVar::Base;	1118	package AnyEvent::CondVar::Base;
		1119
		1120	use overload
		1121	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		1122	fallback => 1;
918		1123
919	sub _send {	1124	sub _send {
920	# nop	1125	# nop
921	}	1126	}
922		1127
…		…
1026	C<PERL_ANYEVENT_MODEL>.	1231	C<PERL_ANYEVENT_MODEL>.
1027		1232
1028	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1233	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1029	model it chooses.	1234	model it chooses.
1030		1235
		1236	=item C<PERL_ANYEVENT_STRICT>
		1237
		1238	AnyEvent does not do much argument checking by default, as thorough
		1239	argument checking is very costly. Setting this variable to a true value
		1240	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1241	check the arguments passed to most method calls. If it finds any problems
		1242	it will croak.
		1243
		1244	In other words, enables "strict" mode.
		1245
		1246	Unlike C<use strict> it is definitely recommended ot keep it off in
		1247	production.
		1248
1031	=item C<PERL_ANYEVENT_MODEL>	1249	=item C<PERL_ANYEVENT_MODEL>
1032		1250
1033	This can be used to specify the event model to be used by AnyEvent, before	1251	This can be used to specify the event model to be used by AnyEvent, before
1034	autodetection and -probing kicks in. It must be a string consisting	1252	auto detection and -probing kicks in. It must be a string consisting
1035	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1253	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1036	and the resulting module name is loaded and if the load was successful,	1254	and the resulting module name is loaded and if the load was successful,
1037	used as event model. If it fails to load AnyEvent will proceed with	1255	used as event model. If it fails to load AnyEvent will proceed with
1038	autodetection and -probing.	1256	auto detection and -probing.
1039		1257
1040	This functionality might change in future versions.	1258	This functionality might change in future versions.
1041		1259
1042	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1260	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1043	could start your program like this:	1261	could start your program like this:
1044		1262
1045	PERL_ANYEVENT_MODEL=Perl perl ...	1263	PERL_ANYEVENT_MODEL=Perl perl ...
1046		1264
1047	=item C<PERL_ANYEVENT_PROTOCOLS>	1265	=item C<PERL_ANYEVENT_PROTOCOLS>
1048		1266
1049	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences	1267	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1050	for IPv4 or IPv6. The default is unspecified (and might change, or be the result	1268	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1051	of autoprobing).	1269	of auto probing).
1052		1270
1053	Must be set to a comma-separated list of protocols or address families,	1271	Must be set to a comma-separated list of protocols or address families,
1054	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be	1272	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1055	used, and preference will be given to protocols mentioned earlier in the	1273	used, and preference will be given to protocols mentioned earlier in the
1056	list.	1274	list.
…		…
1060	small, as the program has to handle connection errors already-	1278	small, as the program has to handle connection errors already-
1061		1279
1062	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,	1280	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1063	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>	1281	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1064	- only support IPv4, never try to resolve or contact IPv6	1282	- only support IPv4, never try to resolve or contact IPv6
1065	addressses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or	1283	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1066	IPv6, but prefer IPv6 over IPv4.	1284	IPv6, but prefer IPv6 over IPv4.
1067		1285
1068	=item C<PERL_ANYEVENT_EDNS0>	1286	=item C<PERL_ANYEVENT_EDNS0>
1069		1287
1070	Used by L<AnyEvent::DNS> to decide wether to use the EDNS0 extension	1288	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1071	for DNS. This extension is generally useful to reduce DNS traffic, but	1289	for DNS. This extension is generally useful to reduce DNS traffic, but
1072	some (broken) firewalls drop such DNS packets, which is why it is off by	1290	some (broken) firewalls drop such DNS packets, which is why it is off by
1073	default.	1291	default.
1074		1292
1075	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce	1293	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1076	EDNS0 in its DNS requests.	1294	EDNS0 in its DNS requests.
		1295
		1296	=item C<PERL_ANYEVENT_MAX_FORKS>
		1297
		1298	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1299	will create in parallel.
1077		1300
1078	=back	1301	=back
1079		1302
1080	=head1 EXAMPLE PROGRAM	1303	=head1 EXAMPLE PROGRAM
1081		1304
…		…
1167	syswrite $txn->{fh}, $txn->{request}	1390	syswrite $txn->{fh}, $txn->{request}
1168	or die "connection or write error";	1391	or die "connection or write error";
1169	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1392	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1170		1393
1171	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1394	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
1172	result and signals any possible waiters that the request ahs finished:	1395	result and signals any possible waiters that the request has finished:
1173		1396
1174	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1397	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1175		1398
1176	if (end-of-file or data complete) {	1399	if (end-of-file or data complete) {
1177	$txn->{result} = $txn->{buf};	1400	$txn->{result} = $txn->{buf};
…		…
1185		1408
1186	$txn->{finished}->recv;	1409	$txn->{finished}->recv;
1187	return $txn->{result};	1410	return $txn->{result};
1188		1411
1189	The actual code goes further and collects all errors (C<die>s, exceptions)	1412	The actual code goes further and collects all errors (C<die>s, exceptions)
1190	that occured during request processing. The C<result> method detects	1413	that occurred during request processing. The C<result> method detects
1191	whether an exception as thrown (it is stored inside the $txn object)	1414	whether an exception as thrown (it is stored inside the $txn object)
1192	and just throws the exception, which means connection errors and other	1415	and just throws the exception, which means connection errors and other
1193	problems get reported tot he code that tries to use the result, not in a	1416	problems get reported tot he code that tries to use the result, not in a
1194	random callback.	1417	random callback.
1195		1418
…		…
1241	of various event loops I prepared some benchmarks.	1464	of various event loops I prepared some benchmarks.
1242		1465
1243	=head2 BENCHMARKING ANYEVENT OVERHEAD	1466	=head2 BENCHMARKING ANYEVENT OVERHEAD
1244		1467
1245	Here is a benchmark of various supported event models used natively and	1468	Here is a benchmark of various supported event models used natively and
1246	through anyevent. The benchmark creates a lot of timers (with a zero	1469	through AnyEvent. The benchmark creates a lot of timers (with a zero
1247	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	1470	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1248	which it is), lets them fire exactly once and destroys them again.	1471	which it is), lets them fire exactly once and destroys them again.
1249		1472
1250	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1473	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1251	distribution.	1474	distribution.
…		…
1374		1597
1375	=back	1598	=back
1376		1599
1377	=head2 BENCHMARKING THE LARGE SERVER CASE	1600	=head2 BENCHMARKING THE LARGE SERVER CASE
1378		1601
1379	This benchmark atcually benchmarks the event loop itself. It works by	1602	This benchmark actually benchmarks the event loop itself. It works by
1380	creating a number of "servers": each server consists of a socketpair, a	1603	creating a number of "servers": each server consists of a socket pair, a
1381	timeout watcher that gets reset on activity (but never fires), and an I/O	1604	timeout watcher that gets reset on activity (but never fires), and an I/O
1382	watcher waiting for input on one side of the socket. Each time the socket	1605	watcher waiting for input on one side of the socket. Each time the socket
1383	watcher reads a byte it will write that byte to a random other "server".	1606	watcher reads a byte it will write that byte to a random other "server".
1384		1607
1385	The effect is that there will be a lot of I/O watchers, only part of which	1608	The effect is that there will be a lot of I/O watchers, only part of which
1386	are active at any one point (so there is a constant number of active	1609	are active at any one point (so there is a constant number of active
1387	fds for each loop iterstaion, but which fds these are is random). The	1610	fds for each loop iteration, but which fds these are is random). The
1388	timeout is reset each time something is read because that reflects how	1611	timeout is reset each time something is read because that reflects how
1389	most timeouts work (and puts extra pressure on the event loops).	1612	most timeouts work (and puts extra pressure on the event loops).
1390		1613
1391	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1614	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1392	(1%) are active. This mirrors the activity of large servers with many	1615	(1%) are active. This mirrors the activity of large servers with many
1393	connections, most of which are idle at any one point in time.	1616	connections, most of which are idle at any one point in time.
1394		1617
1395	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1618	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1396	distribution.	1619	distribution.
…		…
1398	=head3 Explanation of the columns	1621	=head3 Explanation of the columns
1399		1622
1400	I<sockets> is the number of sockets, and twice the number of "servers" (as	1623	I<sockets> is the number of sockets, and twice the number of "servers" (as
1401	each server has a read and write socket end).	1624	each server has a read and write socket end).
1402		1625
1403	I<create> is the time it takes to create a socketpair (which is	1626	I<create> is the time it takes to create a socket pair (which is
1404	nontrivial) and two watchers: an I/O watcher and a timeout watcher.	1627	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1405		1628
1406	I<request>, the most important value, is the time it takes to handle a	1629	I<request>, the most important value, is the time it takes to handle a
1407	single "request", that is, reading the token from the pipe and forwarding	1630	single "request", that is, reading the token from the pipe and forwarding
1408	it to another server. This includes deleting the old timeout and creating	1631	it to another server. This includes deleting the old timeout and creating
…		…
1481	speed most when you have lots of watchers, not when you only have a few of	1704	speed most when you have lots of watchers, not when you only have a few of
1482	them).	1705	them).
1483		1706
1484	EV is again fastest.	1707	EV is again fastest.
1485		1708
1486	Perl again comes second. It is noticably faster than the C-based event	1709	Perl again comes second. It is noticeably faster than the C-based event
1487	loops Event and Glib, although the difference is too small to really	1710	loops Event and Glib, although the difference is too small to really
1488	matter.	1711	matter.
1489		1712
1490	POE also performs much better in this case, but is is still far behind the	1713	POE also performs much better in this case, but is is still far behind the
1491	others.	1714	others.
…		…
1520	specified in the variable.	1743	specified in the variable.
1521		1744
1522	You can make AnyEvent completely ignore this variable by deleting it	1745	You can make AnyEvent completely ignore this variable by deleting it
1523	before the first watcher gets created, e.g. with a C<BEGIN> block:	1746	before the first watcher gets created, e.g. with a C<BEGIN> block:
1524		1747
1525	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1748	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1526		1749
1527	use AnyEvent;	1750	use AnyEvent;
1528		1751
1529	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1752	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1530	be used to probe what backend is used and gain other information (which is	1753	be used to probe what backend is used and gain other information (which is
1531	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	1754	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1755	$ENV{PERL_ANYEGENT_STRICT}.
		1756
		1757
		1758	=head1 BUGS
		1759
		1760	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		1761	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		1762	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		1763	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as
		1764	pronounced).
1532		1765
1533		1766
1534	=head1 SEE ALSO	1767	=head1 SEE ALSO
1535		1768
1536	Utility functions: L<AnyEvent::Util>.	1769	Utility functions: L<AnyEvent::Util>.
…		…
1553	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	1786	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1554		1787
1555		1788
1556	=head1 AUTHOR	1789	=head1 AUTHOR
1557		1790
1558	Marc Lehmann <schmorp@schmorp.de>	1791	Marc Lehmann <schmorp@schmorp.de>
1559	http://home.schmorp.de/	1792	http://home.schmorp.de/
1560		1793
1561	=cut	1794	=cut
1562		1795
1563	1	1796	1
1564		1797

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.127 by root, Sat May 24 01:15:19 2008 UTC vs. Revision 1.173 by root, Mon Jul 21 03:47:22 2008 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.127 by root, Sat May 24 01:15:19 2008 UTC vs.
Revision 1.173 by root, Mon Jul 21 03:47:22 2008 UTC