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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.104 by root, Wed Apr 30 11:40:22 2008 UTC vs.
Revision 1.172 by root, Thu Jul 17 15:21:02 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, Coro::EV, Coro::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
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	15	my $w = AnyEvent->timer (after => $seconds, cb => sub {
16	...	16	...
17	});	17	});
18		18
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	19	my $w = AnyEvent->condvar; # stores whether a condition was flagged
		20	$w->send; # wake up current and all future recv's
20	$w->wait; # enters "main loop" till $condvar gets ->broadcast	21	$w->recv; # enters "main loop" till $condvar gets ->send
21	$w->broadcast; # wake up current and all future wait's	22
		23	=head1 INTRODUCTION/TUTORIAL
		24
		25	This manpage is mainly a reference manual. If you are interested
		26	in a tutorial or some gentle introduction, have a look at the
		27	L<AnyEvent::Intro> manpage.
22		28
23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	29	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24		30
25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	31	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26	nowadays. So what is different about AnyEvent?	32	nowadays. So what is different about AnyEvent?
27		33
28	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of	34	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
29	policy> and AnyEvent is I<small and efficient>.	35	policy> and AnyEvent is I<small and efficient>.
30		36
31	First and foremost, I<AnyEvent is not an event model> itself, it only	37	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	38	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,	39	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,	40	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	41	only one event loop can be active at the same time in a process. AnyEvent
36	helps hiding the differences between those event loops.	42	cannot change this, but it can hide the differences between those event
		43	loops.
37		44
38	The goal of AnyEvent is to offer module authors the ability to do event	45	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	46	programming (waiting for I/O or timer events) without subscribing to a
40	religion, a way of living, and most importantly: without forcing your	47	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	48	module users into the same thing by forcing them to use the same event
42	model you use.	49	model you use.
43		50
44	For modules like POE or IO::Async (which is a total misnomer as it is	51	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	52	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	53	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	54	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	55	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.	56	module are I<also> forced to use the same event loop you use.
50		57
51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	58	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	59	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	60	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,	61	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	62	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	63	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	64	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).	65	to AnyEvent, too, so it is future-proof).
59		66
60	In addition to being free of having to use I<the one and only true event	67	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	68	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	69	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	70	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	71	offering the functionality that is necessary, in as thin as a wrapper as
65	technically possible.	72	technically possible.
66		73
		74	Of course, AnyEvent comes with a big (and fully optional!) toolbox
		75	of useful functionality, such as an asynchronous DNS resolver, 100%
		76	non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
		77	such as Windows) and lots of real-world knowledge and workarounds for
		78	platform bugs and differences.
		79
67	Of course, if you want lots of policy (this can arguably be somewhat	80	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	81	useful) and you want to force your users to use the one and only event
69	model, you should I<not> use this module.	82	model, you should I<not> use this module.
70		83
71	=head1 DESCRIPTION	84	=head1 DESCRIPTION
72		85
…		…
78	The interface itself is vaguely similar, but not identical to the L<Event>	91	The interface itself is vaguely similar, but not identical to the L<Event>
79	module.	92	module.
80		93
81	During the first call of any watcher-creation method, the module tries	94	During the first call of any watcher-creation method, the module tries
82	to detect the currently loaded event loop by probing whether one of the	95	to detect the currently loaded event loop by probing whether one of the
83	following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>,	96	following modules is already loaded: L<EV>,
84	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	97	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,
85	L<POE>. The first one found is used. If none are found, the module tries	98	L<POE>. The first one found is used. If none are found, the module tries
86	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	99	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl
87	adaptor should always succeed) in the order given. The first one that can	100	adaptor should always succeed) in the order given. The first one that can
88	be successfully loaded will be used. If, after this, still none could be	101	be successfully loaded will be used. If, after this, still none could be
…		…
102	starts using it, all bets are off. Maybe you should tell their authors to	115	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...	116	use AnyEvent so their modules work together with others seamlessly...
104		117
105	The pure-perl implementation of AnyEvent is called	118	The pure-perl implementation of AnyEvent is called
106	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	119	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
107	explicitly.	120	explicitly and enjoy the high availability of that event loop :)
108		121
109	=head1 WATCHERS	122	=head1 WATCHERS
110		123
111	AnyEvent has the central concept of a I<watcher>, which is an object that	124	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	125	stores relevant data for each kind of event you are waiting for, such as
113	the callback to call, the filehandle to watch, etc.	126	the callback to call, the file handle to watch, etc.
114		127
115	These watchers are normal Perl objects with normal Perl lifetime. After	128	These watchers are normal Perl objects with normal Perl lifetime. After
116	creating a watcher it will immediately "watch" for events and invoke the	129	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	130	callback when the event occurs (of course, only when the event model
118	is in control).	131	is in control).
…		…
126	Many watchers either are used with "recursion" (repeating timers for	139	Many watchers either are used with "recursion" (repeating timers for
127	example), or need to refer to their watcher object in other ways.	140	example), or need to refer to their watcher object in other ways.
128		141
129	An any way to achieve that is this pattern:	142	An any way to achieve that is this pattern:
130		143
131	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	144	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
132	# you can use $w here, for example to undef it	145	# you can use $w here, for example to undef it
133	undef $w;	146	undef $w;
134	});	147	});
135		148
136	Note that C<my $w; $w => combination. This is necessary because in Perl,	149	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	150	my variables are only visible after the statement in which they are
138	declared.	151	declared.
139		152
140	=head2 I/O WATCHERS	153	=head2 I/O WATCHERS
141		154
142	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	155	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
143	with the following mandatory key-value pairs as arguments:	156	with the following mandatory key-value pairs as arguments:
144		157
145	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	158	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>,	159	(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,	160	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	161	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the
149	becomes ready.	162	callback to invoke each time the file handle becomes ready.
150		163
151	Although the callback might get passed parameters, their value and	164	Although the callback might get passed parameters, their value and
152	presence is undefined and you cannot rely on them. Portable AnyEvent	165	presence is undefined and you cannot rely on them. Portable AnyEvent
153	callbacks cannot use arguments passed to I/O watcher callbacks.	166	callbacks cannot use arguments passed to I/O watcher callbacks.
154		167
…		…
158		171
159	Some event loops issue spurious readyness notifications, so you should	172	Some event loops issue spurious readyness notifications, so you should
160	always use non-blocking calls when reading/writing from/to your file	173	always use non-blocking calls when reading/writing from/to your file
161	handles.	174	handles.
162		175
163	Example:
164
165	# wait for readability of STDIN, then read a line and disable the watcher	176	Example: wait for readability of STDIN, then read a line and disable the
		177	watcher.
		178
166	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	179	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
167	chomp (my $input = <STDIN>);	180	chomp (my $input = <STDIN>);
168	warn "read: $input\n";	181	warn "read: $input\n";
169	undef $w;	182	undef $w;
170	});	183	});
…		…
180		193
181	Although the callback might get passed parameters, their value and	194	Although the callback might get passed parameters, their value and
182	presence is undefined and you cannot rely on them. Portable AnyEvent	195	presence is undefined and you cannot rely on them. Portable AnyEvent
183	callbacks cannot use arguments passed to time watcher callbacks.	196	callbacks cannot use arguments passed to time watcher callbacks.
184		197
185	The timer callback will be invoked at most once: if you want a repeating	198	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	199	parameter, C<interval>, as a strictly positive number (> 0), then the
187	and Glib).	200	callback will be invoked regularly at that interval (in fractional
		201	seconds) after the first invocation. If C<interval> is specified with a
		202	false value, then it is treated as if it were missing.
188		203
189	Example:	204	The callback will be rescheduled before invoking the callback, but no
		205	attempt is done to avoid timer drift in most backends, so the interval is
		206	only approximate.
190		207
191	# fire an event after 7.7 seconds	208	Example: fire an event after 7.7 seconds.
		209
192	my $w = AnyEvent->timer (after => 7.7, cb => sub {	210	my $w = AnyEvent->timer (after => 7.7, cb => sub {
193	warn "timeout\n";	211	warn "timeout\n";
194	});	212	});
195		213
196	# to cancel the timer:	214	# to cancel the timer:
197	undef $w;	215	undef $w;
198		216
199	Example 2:
200
201	# fire an event after 0.5 seconds, then roughly every second	217	Example 2: fire an event after 0.5 seconds, then roughly every second.
202	my $w;
203		218
204	my $cb = sub {
205	# cancel the old timer while creating a new one
206	$w = AnyEvent->timer (after => 1, cb => $cb);	219	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		220	warn "timeout\n";
207	};	221	};
208
209	# start the "loop" by creating the first watcher
210	$w = AnyEvent->timer (after => 0.5, cb => $cb);
211		222
212	=head3 TIMING ISSUES	223	=head3 TIMING ISSUES
213		224
214	There are two ways to handle timers: based on real time (relative, "fire	225	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	226	in 10 seconds") and based on wallclock time (absolute, "fire at 12
…		…
227	timers.	238	timers.
228		239
229	AnyEvent always prefers relative timers, if available, matching the	240	AnyEvent always prefers relative timers, if available, matching the
230	AnyEvent API.	241	AnyEvent API.
231		242
		243	AnyEvent has two additional methods that return the "current time":
		244
		245	=over 4
		246
		247	=item AnyEvent->time
		248
		249	This returns the "current wallclock time" as a fractional number of
		250	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
		251	return, and the result is guaranteed to be compatible with those).
		252
		253	It progresses independently of any event loop processing, i.e. each call
		254	will check the system clock, which usually gets updated frequently.
		255
		256	=item AnyEvent->now
		257
		258	This also returns the "current wallclock time", but unlike C<time>, above,
		259	this value might change only once per event loop iteration, depending on
		260	the event loop (most return the same time as C<time>, above). This is the
		261	time that AnyEvent's timers get scheduled against.
		262
		263	I<In almost all cases (in all cases if you don't care), this is the
		264	function to call when you want to know the current time.>
		265
		266	This function is also often faster then C<< AnyEvent->time >>, and
		267	thus the preferred method if you want some timestamp (for example,
		268	L<AnyEvent::Handle> uses this to update it's activity timeouts).
		269
		270	The rest of this section is only of relevance if you try to be very exact
		271	with your timing, you can skip it without bad conscience.
		272
		273	For a practical example of when these times differ, consider L<Event::Lib>
		274	and L<EV> and the following set-up:
		275
		276	The event loop is running and has just invoked one of your callback at
		277	time=500 (assume no other callbacks delay processing). In your callback,
		278	you wait a second by executing C<sleep 1> (blocking the process for a
		279	second) and then (at time=501) you create a relative timer that fires
		280	after three seconds.
		281
		282	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
		283	both return C<501>, because that is the current time, and the timer will
		284	be scheduled to fire at time=504 (C<501> + C<3>).
		285
		286	With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
		287	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
		288	last event processing phase started. With L<EV>, your timer gets scheduled
		289	to run at time=503 (C<500> + C<3>).
		290
		291	In one sense, L<Event::Lib> is more exact, as it uses the current time
		292	regardless of any delays introduced by event processing. However, most
		293	callbacks do not expect large delays in processing, so this causes a
		294	higher drift (and a lot more system calls to get the current time).
		295
		296	In another sense, L<EV> is more exact, as your timer will be scheduled at
		297	the same time, regardless of how long event processing actually took.
		298
		299	In either case, if you care (and in most cases, you don't), then you
		300	can get whatever behaviour you want with any event loop, by taking the
		301	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
		302	account.
		303
		304	=back
		305
232	=head2 SIGNAL WATCHERS	306	=head2 SIGNAL WATCHERS
233		307
234	You can watch for signals using a signal watcher, C<signal> is the signal	308	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	309	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
236	be invoked whenever a signal occurs.	310	callback to be invoked whenever a signal occurs.
237		311
238	Although the callback might get passed parameters, their value and	312	Although the callback might get passed parameters, their value and
239	presence is undefined and you cannot rely on them. Portable AnyEvent	313	presence is undefined and you cannot rely on them. Portable AnyEvent
240	callbacks cannot use arguments passed to signal watcher callbacks.	314	callbacks cannot use arguments passed to signal watcher callbacks.
241		315
242	Multiple signal occurances can be clumped together into one callback	316	Multiple signal occurrences can be clumped together into one callback
243	invocation, and callback invocation will be synchronous. synchronous means	317	invocation, and callback invocation will be synchronous. Synchronous means
244	that it might take a while until the signal gets handled by the process,	318	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.	319	but it is guaranteed not to interrupt any other callbacks.
246		320
247	The main advantage of using these watchers is that you can share a signal	321	The main advantage of using these watchers is that you can share a signal
248	between multiple watchers.	322	between multiple watchers.
249		323
250	This watcher might use C<%SIG>, so programs overwriting those signals	324	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	351	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>).	352	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
279		353
280	Example: fork a process and wait for it	354	Example: fork a process and wait for it
281		355
282	my $done = AnyEvent->condvar;	356	my $done = AnyEvent->condvar;
283		357
284	AnyEvent::detect; # force event module to be initialised
285
286	my $pid = fork or exit 5;	358	my $pid = fork or exit 5;
287		359
288	my $w = AnyEvent->child (	360	my $w = AnyEvent->child (
289	pid => $pid,	361	pid => $pid,
290	cb => sub {	362	cb => sub {
291	my ($pid, $status) = @_;	363	my ($pid, $status) = @_;
292	warn "pid $pid exited with status $status";	364	warn "pid $pid exited with status $status";
293	$done->broadcast;	365	$done->send;
294	},	366	},
295	);	367	);
296		368
297	# do something else, then wait for process exit	369	# do something else, then wait for process exit
298	$done->wait;	370	$done->recv;
299		371
300	=head2 CONDITION VARIABLES	372	=head2 CONDITION VARIABLES
301		373
		374	If you are familiar with some event loops you will know that all of them
		375	require you to run some blocking "loop", "run" or similar function that
		376	will actively watch for new events and call your callbacks.
		377
		378	AnyEvent is different, it expects somebody else to run the event loop and
		379	will only block when necessary (usually when told by the user).
		380
		381	The instrument to do that is called a "condition variable", so called
		382	because they represent a condition that must become true.
		383
302	Condition variables can be created by calling the C<< AnyEvent->condvar >>	384	Condition variables can be created by calling the C<< AnyEvent->condvar
303	method without any arguments.	385	>> method, usually without arguments. The only argument pair allowed is
		386	C<cb>, which specifies a callback to be called when the condition variable
		387	becomes true.
304		388
305	A condition variable waits for a condition - precisely that the C<<	389	After creation, the condition variable is "false" until it becomes "true"
306	->broadcast >> method has been called.	390	by calling the C<send> method (or calling the condition variable as if it
		391	were a callback, read about the caveats in the description for the C<<
		392	->send >> method).
307		393
308	They are very useful to signal that a condition has been fulfilled, for	394	Condition variables are similar to callbacks, except that you can
		395	optionally wait for them. They can also be called merge points - points
		396	in time where multiple outstanding events have been processed. And yet
		397	another way to call them is transactions - each condition variable can be
		398	used to represent a transaction, which finishes at some point and delivers
		399	a result.
		400
		401	Condition variables are very useful to signal that something has finished,
309	example, if you write a module that does asynchronous http requests,	402	for example, if you write a module that does asynchronous http requests,
310	then a condition variable would be the ideal candidate to signal the	403	then a condition variable would be the ideal candidate to signal the
311	availability of results.	404	availability of results. The user can either act when the callback is
		405	called or can synchronously C<< ->recv >> for the results.
312		406
313	You can also use condition variables to block your main program until	407	You can also use them to simulate traditional event loops - for example,
314	an event occurs - for example, you could C<< ->wait >> in your main	408	you can block your main program until an event occurs - for example, you
315	program until the user clicks the Quit button in your app, which would C<<	409	could C<< ->recv >> in your main program until the user clicks the Quit
316	->broadcast >> the "quit" event.	410	button of your app, which would C<< ->send >> the "quit" event.
317		411
318	Note that condition variables recurse into the event loop - if you have	412	Note that condition variables recurse into the event loop - if you have
319	two pirces of code that call C<< ->wait >> in a round-robbin fashion, you	413	two pieces of code that call C<< ->recv >> in a round-robin fashion, you
320	lose. Therefore, condition variables are good to export to your caller, but	414	lose. Therefore, condition variables are good to export to your caller, but
321	you should avoid making a blocking wait yourself, at least in callbacks,	415	you should avoid making a blocking wait yourself, at least in callbacks,
322	as this asks for trouble.	416	as this asks for trouble.
323		417
324	This object has two methods:	418	Condition variables are represented by hash refs in perl, and the keys
		419	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
		420	easy (it is often useful to build your own transaction class on top of
		421	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
		422	it's C<new> method in your own C<new> method.
		423
		424	There are two "sides" to a condition variable - the "producer side" which
		425	eventually calls C<< -> send >>, and the "consumer side", which waits
		426	for the send to occur.
		427
		428	Example: wait for a timer.
		429
		430	# wait till the result is ready
		431	my $result_ready = AnyEvent->condvar;
		432
		433	# do something such as adding a timer
		434	# or socket watcher the calls $result_ready->send
		435	# when the "result" is ready.
		436	# in this case, we simply use a timer:
		437	my $w = AnyEvent->timer (
		438	after => 1,
		439	cb => sub { $result_ready->send },
		440	);
		441
		442	# this "blocks" (while handling events) till the callback
		443	# calls send
		444	$result_ready->recv;
		445
		446	Example: wait for a timer, but take advantage of the fact that
		447	condition variables are also code references.
		448
		449	my $done = AnyEvent->condvar;
		450	my $delay = AnyEvent->timer (after => 5, cb => $done);
		451	$done->recv;
		452
		453	=head3 METHODS FOR PRODUCERS
		454
		455	These methods should only be used by the producing side, i.e. the
		456	code/module that eventually sends the signal. Note that it is also
		457	the producer side which creates the condvar in most cases, but it isn't
		458	uncommon for the consumer to create it as well.
325		459
326	=over 4	460	=over 4
327		461
		462	=item $cv->send (...)
		463
		464	Flag the condition as ready - a running C<< ->recv >> and all further
		465	calls to C<recv> will (eventually) return after this method has been
		466	called. If nobody is waiting the send will be remembered.
		467
		468	If a callback has been set on the condition variable, it is called
		469	immediately from within send.
		470
		471	Any arguments passed to the C<send> call will be returned by all
		472	future C<< ->recv >> calls.
		473
		474	Condition variables are overloaded so one can call them directly
		475	(as a code reference). Calling them directly is the same as calling
		476	C<send>. Note, however, that many C-based event loops do not handle
		477	overloading, so as tempting as it may be, passing a condition variable
		478	instead of a callback does not work. Both the pure perl and EV loops
		479	support overloading, however, as well as all functions that use perl to
		480	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
		481	example).
		482
		483	=item $cv->croak ($error)
		484
		485	Similar to send, but causes all call's to C<< ->recv >> to invoke
		486	C<Carp::croak> with the given error message/object/scalar.
		487
		488	This can be used to signal any errors to the condition variable
		489	user/consumer.
		490
		491	=item $cv->begin ([group callback])
		492
328	=item $cv->wait	493	=item $cv->end
329		494
330	Wait (blocking if necessary) until the C<< ->broadcast >> method has been	495	These two methods are EXPERIMENTAL and MIGHT CHANGE.
		496
		497	These two methods can be used to combine many transactions/events into
		498	one. For example, a function that pings many hosts in parallel might want
		499	to use a condition variable for the whole process.
		500
		501	Every call to C<< ->begin >> will increment a counter, and every call to
		502	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
		503	>>, the (last) callback passed to C<begin> will be executed. That callback
		504	is I<supposed> to call C<< ->send >>, but that is not required. If no
		505	callback was set, C<send> will be called without any arguments.
		506
		507	Let's clarify this with the ping example:
		508
		509	my $cv = AnyEvent->condvar;
		510
		511	my %result;
		512	$cv->begin (sub { $cv->send (\%result) });
		513
		514	for my $host (@list_of_hosts) {
		515	$cv->begin;
		516	ping_host_then_call_callback $host, sub {
		517	$result{$host} = ...;
		518	$cv->end;
		519	};
		520	}
		521
		522	$cv->end;
		523
		524	This code fragment supposedly pings a number of hosts and calls
		525	C<send> after results for all then have have been gathered - in any
		526	order. To achieve this, the code issues a call to C<begin> when it starts
		527	each ping request and calls C<end> when it has received some result for
		528	it. Since C<begin> and C<end> only maintain a counter, the order in which
		529	results arrive is not relevant.
		530
		531	There is an additional bracketing call to C<begin> and C<end> outside the
		532	loop, which serves two important purposes: first, it sets the callback
		533	to be called once the counter reaches C<0>, and second, it ensures that
		534	C<send> is called even when C<no> hosts are being pinged (the loop
		535	doesn't execute once).
		536
		537	This is the general pattern when you "fan out" into multiple subrequests:
		538	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>
		539	is called at least once, and then, for each subrequest you start, call
		540	C<begin> and for each subrequest you finish, call C<end>.
		541
		542	=back
		543
		544	=head3 METHODS FOR CONSUMERS
		545
		546	These methods should only be used by the consuming side, i.e. the
		547	code awaits the condition.
		548
		549	=over 4
		550
		551	=item $cv->recv
		552
		553	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
331	called on c<$cv>, while servicing other watchers normally.	554	>> methods have been called on c<$cv>, while servicing other watchers
		555	normally.
332		556
333	You can only wait once on a condition - additional calls will return	557	You can only wait once on a condition - additional calls are valid but
334	immediately.	558	will return immediately.
		559
		560	If an error condition has been set by calling C<< ->croak >>, then this
		561	function will call C<croak>.
		562
		563	In list context, all parameters passed to C<send> will be returned,
		564	in scalar context only the first one will be returned.
335		565
336	Not all event models support a blocking wait - some die in that case	566	Not all event models support a blocking wait - some die in that case
337	(programs might want to do that to stay interactive), so I<if you are	567	(programs might want to do that to stay interactive), so I<if you are
338	using this from a module, never require a blocking wait>, but let the	568	using this from a module, never require a blocking wait>, but let the
339	caller decide whether the call will block or not (for example, by coupling	569	caller decide whether the call will block or not (for example, by coupling
340	condition variables with some kind of request results and supporting	570	condition variables with some kind of request results and supporting
341	callbacks so the caller knows that getting the result will not block,	571	callbacks so the caller knows that getting the result will not block,
342	while still suppporting blocking waits if the caller so desires).	572	while still supporting blocking waits if the caller so desires).
343		573
344	Another reason I<never> to C<< ->wait >> in a module is that you cannot	574	Another reason I<never> to C<< ->recv >> in a module is that you cannot
345	sensibly have two C<< ->wait >>'s in parallel, as that would require	575	sensibly have two C<< ->recv >>'s in parallel, as that would require
346	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	576	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
347	can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and	577	can supply.
348	L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
349	from different coroutines, however).
350		578
351	=item $cv->broadcast	579	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
		580	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
		581	versions and also integrates coroutines into AnyEvent, making blocking
		582	C<< ->recv >> calls perfectly safe as long as they are done from another
		583	coroutine (one that doesn't run the event loop).
352		584
353	Flag the condition as ready - a running C<< ->wait >> and all further	585	You can ensure that C<< -recv >> never blocks by setting a callback and
354	calls to C<wait> will (eventually) return after this method has been	586	only calling C<< ->recv >> from within that callback (or at a later
355	called. If nobody is waiting the broadcast will be remembered..	587	time). This will work even when the event loop does not support blocking
		588	waits otherwise.
		589
		590	=item $bool = $cv->ready
		591
		592	Returns true when the condition is "true", i.e. whether C<send> or
		593	C<croak> have been called.
		594
		595	=item $cb = $cv->cb ([new callback])
		596
		597	This is a mutator function that returns the callback set and optionally
		598	replaces it before doing so.
		599
		600	The callback will be called when the condition becomes "true", i.e. when
		601	C<send> or C<croak> are called, with the only argument being the condition
		602	variable itself. Calling C<recv> inside the callback or at any later time
		603	is guaranteed not to block.
356		604
357	=back	605	=back
358
359	Example:
360
361	# wait till the result is ready
362	my $result_ready = AnyEvent->condvar;
363
364	# do something such as adding a timer
365	# or socket watcher the calls $result_ready->broadcast
366	# when the "result" is ready.
367	# in this case, we simply use a timer:
368	my $w = AnyEvent->timer (
369	after => 1,
370	cb => sub { $result_ready->broadcast },
371	);
372
373	# this "blocks" (while handling events) till the watcher
374	# calls broadcast
375	$result_ready->wait;
376		606
377	=head1 GLOBAL VARIABLES AND FUNCTIONS	607	=head1 GLOBAL VARIABLES AND FUNCTIONS
378		608
379	=over 4	609	=over 4
380		610
…		…
386	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	616	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
387	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	617	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
388		618
389	The known classes so far are:	619	The known classes so far are:
390		620
391	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
392	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
393	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).	621	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
394	AnyEvent::Impl::Event based on Event, second best choice.	622	AnyEvent::Impl::Event based on Event, second best choice.
395	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	623	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
396	AnyEvent::Impl::Glib based on Glib, third-best choice.	624	AnyEvent::Impl::Glib based on Glib, third-best choice.
397	AnyEvent::Impl::Tk based on Tk, very bad choice.	625	AnyEvent::Impl::Tk based on Tk, very bad choice.
…		…
414	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	642	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
415	if necessary. You should only call this function right before you would	643	if necessary. You should only call this function right before you would
416	have created an AnyEvent watcher anyway, that is, as late as possible at	644	have created an AnyEvent watcher anyway, that is, as late as possible at
417	runtime.	645	runtime.
418		646
		647	=item $guard = AnyEvent::post_detect { BLOCK }
		648
		649	Arranges for the code block to be executed as soon as the event model is
		650	autodetected (or immediately if this has already happened).
		651
		652	If called in scalar or list context, then it creates and returns an object
		653	that automatically removes the callback again when it is destroyed. See
		654	L<Coro::BDB> for a case where this is useful.
		655
		656	=item @AnyEvent::post_detect
		657
		658	If there are any code references in this array (you can C<push> to it
		659	before or after loading AnyEvent), then they will called directly after
		660	the event loop has been chosen.
		661
		662	You should check C<$AnyEvent::MODEL> before adding to this array, though:
		663	if it contains a true value then the event loop has already been detected,
		664	and the array will be ignored.
		665
		666	Best use C<AnyEvent::post_detect { BLOCK }> instead.
		667
419	=back	668	=back
420		669
421	=head1 WHAT TO DO IN A MODULE	670	=head1 WHAT TO DO IN A MODULE
422		671
423	As a module author, you should C<use AnyEvent> and call AnyEvent methods	672	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
426	Be careful when you create watchers in the module body - AnyEvent will	675	Be careful when you create watchers in the module body - AnyEvent will
427	decide which event module to use as soon as the first method is called, so	676	decide which event module to use as soon as the first method is called, so
428	by calling AnyEvent in your module body you force the user of your module	677	by calling AnyEvent in your module body you force the user of your module
429	to load the event module first.	678	to load the event module first.
430		679
431	Never call C<< ->wait >> on a condition variable unless you I<know> that	680	Never call C<< ->recv >> on a condition variable unless you I<know> that
432	the C<< ->broadcast >> method has been called on it already. This is	681	the C<< ->send >> method has been called on it already. This is
433	because it will stall the whole program, and the whole point of using	682	because it will stall the whole program, and the whole point of using
434	events is to stay interactive.	683	events is to stay interactive.
435		684
436	It is fine, however, to call C<< ->wait >> when the user of your module	685	It is fine, however, to call C<< ->recv >> when the user of your module
437	requests it (i.e. if you create a http request object ad have a method	686	requests it (i.e. if you create a http request object ad have a method
438	called C<results> that returns the results, it should call C<< ->wait >>	687	called C<results> that returns the results, it should call C<< ->recv >>
439	freely, as the user of your module knows what she is doing. always).	688	freely, as the user of your module knows what she is doing. always).
440		689
441	=head1 WHAT TO DO IN THE MAIN PROGRAM	690	=head1 WHAT TO DO IN THE MAIN PROGRAM
442		691
443	There will always be a single main program - the only place that should	692	There will always be a single main program - the only place that should
…		…
445		694
446	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	695	If it doesn't care, it can just "use AnyEvent" and use it itself, or not
447	do anything special (it does not need to be event-based) and let AnyEvent	696	do anything special (it does not need to be event-based) and let AnyEvent
448	decide which implementation to chose if some module relies on it.	697	decide which implementation to chose if some module relies on it.
449		698
450	If the main program relies on a specific event model. For example, in	699	If the main program relies on a specific event model - for example, in
451	Gtk2 programs you have to rely on the Glib module. You should load the	700	Gtk2 programs you have to rely on the Glib module - you should load the
452	event module before loading AnyEvent or any module that uses it: generally	701	event module before loading AnyEvent or any module that uses it: generally
453	speaking, you should load it as early as possible. The reason is that	702	speaking, you should load it as early as possible. The reason is that
454	modules might create watchers when they are loaded, and AnyEvent will	703	modules might create watchers when they are loaded, and AnyEvent will
455	decide on the event model to use as soon as it creates watchers, and it	704	decide on the event model to use as soon as it creates watchers, and it
456	might chose the wrong one unless you load the correct one yourself.	705	might chose the wrong one unless you load the correct one yourself.
457		706
458	You can chose to use a rather inefficient pure-perl implementation by	707	You can chose to use a pure-perl implementation by loading the
459	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	708	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
460	behaviour everywhere, but letting AnyEvent chose is generally better.	709	everywhere, but letting AnyEvent chose the model is generally better.
		710
		711	=head2 MAINLOOP EMULATION
		712
		713	Sometimes (often for short test scripts, or even standalone programs who
		714	only want to use AnyEvent), you do not want to run a specific event loop.
		715
		716	In that case, you can use a condition variable like this:
		717
		718	AnyEvent->condvar->recv;
		719
		720	This has the effect of entering the event loop and looping forever.
		721
		722	Note that usually your program has some exit condition, in which case
		723	it is better to use the "traditional" approach of storing a condition
		724	variable somewhere, waiting for it, and sending it when the program should
		725	exit cleanly.
		726
461		727
462	=head1 OTHER MODULES	728	=head1 OTHER MODULES
463		729
464	The following is a non-exhaustive list of additional modules that use	730	The following is a non-exhaustive list of additional modules that use
465	AnyEvent and can therefore be mixed easily with other AnyEvent modules	731	AnyEvent and can therefore be mixed easily with other AnyEvent modules
…		…
471	=item L<AnyEvent::Util>	737	=item L<AnyEvent::Util>
472		738
473	Contains various utility functions that replace often-used but blocking	739	Contains various utility functions that replace often-used but blocking
474	functions such as C<inet_aton> by event-/callback-based versions.	740	functions such as C<inet_aton> by event-/callback-based versions.
475		741
		742	=item L<AnyEvent::Socket>
		743
		744	Provides various utility functions for (internet protocol) sockets,
		745	addresses and name resolution. Also functions to create non-blocking tcp
		746	connections or tcp servers, with IPv6 and SRV record support and more.
		747
476	=item L<AnyEvent::Handle>	748	=item L<AnyEvent::Handle>
477		749
478	Provide read and write buffers and manages watchers for reads and writes.	750	Provide read and write buffers, manages watchers for reads and writes,
		751	supports raw and formatted I/O, I/O queued and fully transparent and
		752	non-blocking SSL/TLS.
479		753
480	=item L<AnyEvent::Socket>	754	=item L<AnyEvent::DNS>
481		755
482	Provides a means to do non-blocking connects, accepts etc.	756	Provides rich asynchronous DNS resolver capabilities.
		757
		758	=item L<AnyEvent::HTTP>
		759
		760	A simple-to-use HTTP library that is capable of making a lot of concurrent
		761	HTTP requests.
483		762
484	=item L<AnyEvent::HTTPD>	763	=item L<AnyEvent::HTTPD>
485		764
486	Provides a simple web application server framework.	765	Provides a simple web application server framework.
487		766
488	=item L<AnyEvent::DNS>
489
490	Provides asynchronous DNS resolver capabilities, beyond what
491	L<AnyEvent::Util> offers.
492
493	=item L<AnyEvent::FastPing>	767	=item L<AnyEvent::FastPing>
494		768
495	The fastest ping in the west.	769	The fastest ping in the west.
		770
		771	=item L<AnyEvent::DBI>
		772
		773	Executes L<DBI> requests asynchronously in a proxy process.
		774
		775	=item L<AnyEvent::AIO>
		776
		777	Truly asynchronous I/O, should be in the toolbox of every event
		778	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		779	together.
		780
		781	=item L<AnyEvent::BDB>
		782
		783	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		784	L<BDB> and AnyEvent together.
		785
		786	=item L<AnyEvent::GPSD>
		787
		788	A non-blocking interface to gpsd, a daemon delivering GPS information.
		789
		790	=item L<AnyEvent::IGS>
		791
		792	A non-blocking interface to the Internet Go Server protocol (used by
		793	L<App::IGS>).
496		794
497	=item L<Net::IRC3>	795	=item L<Net::IRC3>
498		796
499	AnyEvent based IRC client module family.	797	AnyEvent based IRC client module family.
500		798
…		…
511		809
512	High level API for event-based execution flow control.	810	High level API for event-based execution flow control.
513		811
514	=item L<Coro>	812	=item L<Coro>
515		813
516	Has special support for AnyEvent.	814	Has special support for AnyEvent via L<Coro::AnyEvent>.
517		815
518	=item L<IO::Lambda>	816	=item L<IO::Lambda>
519		817
520	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	818	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
521
522	=item L<IO::AIO>
523
524	Truly asynchronous I/O, should be in the toolbox of every event
525	programmer. Can be trivially made to use AnyEvent.
526
527	=item L<BDB>
528
529	Truly asynchronous Berkeley DB access. Can be trivially made to use
530	AnyEvent.
531		819
532	=back	820	=back
533		821
534	=cut	822	=cut
535		823
…		…
538	no warnings;	826	no warnings;
539	use strict;	827	use strict;
540		828
541	use Carp;	829	use Carp;
542		830
543	our $VERSION = '3.3';	831	our $VERSION = 4.22;
544	our $MODEL;	832	our $MODEL;
545		833
546	our $AUTOLOAD;	834	our $AUTOLOAD;
547	our @ISA;	835	our @ISA;
548		836
		837	our @REGISTRY;
		838
		839	our $WIN32;
		840
		841	BEGIN {
		842	my $win32 = ! ! ($^O =~ /mswin32/i);
		843	eval "sub WIN32(){ $win32 }";
		844	}
		845
549	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	846	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
550		847
551	our @REGISTRY;	848	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
		849
		850	{
		851	my $idx;
		852	$PROTOCOL{$_} = ++$idx
		853	for reverse split /\s,\s/,
		854	$ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
		855	}
552		856
553	my @models = (	857	my @models = (
554	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
555	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
556	[EV:: => AnyEvent::Impl::EV::],	858	[EV:: => AnyEvent::Impl::EV::],
557	[Event:: => AnyEvent::Impl::Event::],	859	[Event:: => AnyEvent::Impl::Event::],
558	[Tk:: => AnyEvent::Impl::Tk::],
559	[Wx:: => AnyEvent::Impl::POE::],
560	[Prima:: => AnyEvent::Impl::POE::],
561	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	860	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
562	# everything below here will not be autoprobed as the pureperl backend should work everywhere	861	# everything below here will not be autoprobed
563	[Glib:: => AnyEvent::Impl::Glib::],	862	# as the pureperl backend should work everywhere
		863	# and is usually faster
		864	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		865	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
564	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	866	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
565	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	867	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
566	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	868	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
		869	[Wx:: => AnyEvent::Impl::POE::],
		870	[Prima:: => AnyEvent::Impl::POE::],
567	);	871	);
568		872
569	our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY);	873	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
		874
		875	our @post_detect;
		876
		877	sub post_detect(&) {
		878	my ($cb) = @_;
		879
		880	if ($MODEL) {
		881	$cb->();
		882
		883	1
		884	} else {
		885	push @post_detect, $cb;
		886
		887	defined wantarray
		888	? bless \$cb, "AnyEvent::Util::PostDetect"
		889	: ()
		890	}
		891	}
		892
		893	sub AnyEvent::Util::PostDetect::DESTROY {
		894	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		895	}
570		896
571	sub detect() {	897	sub detect() {
572	unless ($MODEL) {	898	unless ($MODEL) {
573	no strict 'refs';	899	no strict 'refs';
		900	local $SIG{__DIE__};
574		901
575	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	902	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
576	my $model = "AnyEvent::Impl::$1";	903	my $model = "AnyEvent::Impl::$1";
577	if (eval "require $model") {	904	if (eval "require $model") {
578	$MODEL = $model;	905	$MODEL = $model;
…		…
608	last;	935	last;
609	}	936	}
610	}	937	}
611		938
612	$MODEL	939	$MODEL
613	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib.";	940	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
614	}	941	}
615	}	942	}
616		943
		944	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		945
617	unshift @ISA, $MODEL;	946	unshift @ISA, $MODEL;
618	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	947
		948	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		949
		950	(shift @post_detect)->() while @post_detect;
619	}	951	}
620		952
621	$MODEL	953	$MODEL
622	}	954	}
623		955
…		…
631		963
632	my $class = shift;	964	my $class = shift;
633	$class->$func (@_);	965	$class->$func (@_);
634	}	966	}
635		967
		968	# utility function to dup a filehandle. this is used by many backends
		969	# to support binding more than one watcher per filehandle (they usually
		970	# allow only one watcher per fd, so we dup it to get a different one).
		971	sub _dupfh($$$$) {
		972	my ($poll, $fh, $r, $w) = @_;
		973
		974	require Fcntl;
		975
		976	# cygwin requires the fh mode to be matching, unix doesn't
		977	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		978	: $poll eq "w" ? ($w, ">")
		979	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		980
		981	open my $fh2, "$mode&" . fileno $fh
		982	or die "cannot dup() filehandle: $!";
		983
		984	# we assume CLOEXEC is already set by perl in all important cases
		985
		986	($fh2, $rw)
		987	}
		988
636	package AnyEvent::Base;	989	package AnyEvent::Base;
637		990
		991	# default implementation for now and time
		992
		993	use Time::HiRes ();
		994
		995	sub time { Time::HiRes::time }
		996	sub now { Time::HiRes::time }
		997
638	# default implementation for ->condvar, ->wait, ->broadcast	998	# default implementation for ->condvar
639		999
640	sub condvar {	1000	sub condvar {
641	bless \my $flag, "AnyEvent::Base::CondVar"	1001	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
642	}
643
644	sub AnyEvent::Base::CondVar::broadcast {
645	${$_[0]}++;
646	}
647
648	sub AnyEvent::Base::CondVar::wait {
649	AnyEvent->one_event while !${$_[0]};
650	}	1002	}
651		1003
652	# default implementation for ->signal	1004	# default implementation for ->signal
653		1005
654	our %SIG_CB;	1006	our %SIG_CB;
…		…
670	sub AnyEvent::Base::Signal::DESTROY {	1022	sub AnyEvent::Base::Signal::DESTROY {
671	my ($signal, $cb) = @{$_[0]};	1023	my ($signal, $cb) = @{$_[0]};
672		1024
673	delete $SIG_CB{$signal}{$cb};	1025	delete $SIG_CB{$signal}{$cb};
674		1026
675	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1027	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
676	}	1028	}
677		1029
678	# default implementation for ->child	1030	# default implementation for ->child
679		1031
680	our %PID_CB;	1032	our %PID_CB;
…		…
707	or Carp::croak "required option 'pid' is missing";	1059	or Carp::croak "required option 'pid' is missing";
708		1060
709	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1061	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
710		1062
711	unless ($WNOHANG) {	1063	unless ($WNOHANG) {
712	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } \|\| 1;	1064	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
713	}	1065	}
714		1066
715	unless ($CHLD_W) {	1067	unless ($CHLD_W) {
716	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1068	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
717	# child could be a zombie already, so make at least one round	1069	# child could be a zombie already, so make at least one round
…		…
727	delete $PID_CB{$pid}{$cb};	1079	delete $PID_CB{$pid}{$cb};
728	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1080	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
729		1081
730	undef $CHLD_W unless keys %PID_CB;	1082	undef $CHLD_W unless keys %PID_CB;
731	}	1083	}
		1084
		1085	package AnyEvent::CondVar;
		1086
		1087	our @ISA = AnyEvent::CondVar::Base::;
		1088
		1089	package AnyEvent::CondVar::Base;
		1090
		1091	use overload
		1092	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		1093	fallback => 1;
		1094
		1095	sub _send {
		1096	# nop
		1097	}
		1098
		1099	sub send {
		1100	my $cv = shift;
		1101	$cv->{_ae_sent} = [@_];
		1102	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		1103	$cv->_send;
		1104	}
		1105
		1106	sub croak {
		1107	$_[0]{_ae_croak} = $_[1];
		1108	$_[0]->send;
		1109	}
		1110
		1111	sub ready {
		1112	$_[0]{_ae_sent}
		1113	}
		1114
		1115	sub _wait {
		1116	AnyEvent->one_event while !$_[0]{_ae_sent};
		1117	}
		1118
		1119	sub recv {
		1120	$_[0]->_wait;
		1121
		1122	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		1123	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		1124	}
		1125
		1126	sub cb {
		1127	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		1128	$_[0]{_ae_cb}
		1129	}
		1130
		1131	sub begin {
		1132	++$_[0]{_ae_counter};
		1133	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		1134	}
		1135
		1136	sub end {
		1137	return if --$_[0]{_ae_counter};
		1138	&{ $_[0]{_ae_end_cb} \|\| sub { $_[0]->send } };
		1139	}
		1140
		1141	# undocumented/compatibility with pre-3.4
		1142	*broadcast = \&send;
		1143	*wait = \&_wait;
732		1144
733	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1145	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
734		1146
735	This is an advanced topic that you do not normally need to use AnyEvent in	1147	This is an advanced topic that you do not normally need to use AnyEvent in
736	a module. This section is only of use to event loop authors who want to	1148	a module. This section is only of use to event loop authors who want to
…		…
790	C<PERL_ANYEVENT_MODEL>.	1202	C<PERL_ANYEVENT_MODEL>.
791		1203
792	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1204	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
793	model it chooses.	1205	model it chooses.
794		1206
		1207	=item C<PERL_ANYEVENT_STRICT>
		1208
		1209	AnyEvent does not do much argument checking by default, as thorough
		1210	argument checking is very costly. Setting this variable to a true value
		1211	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1212	check the arguments passed to most method calls. If it finds any problems
		1213	it will croak.
		1214
		1215	In other words, enables "strict" mode.
		1216
		1217	Unlike C<use strict> it is definitely recommended ot keep it off in
		1218	production.
		1219
795	=item C<PERL_ANYEVENT_MODEL>	1220	=item C<PERL_ANYEVENT_MODEL>
796		1221
797	This can be used to specify the event model to be used by AnyEvent, before	1222	This can be used to specify the event model to be used by AnyEvent, before
798	autodetection and -probing kicks in. It must be a string consisting	1223	auto detection and -probing kicks in. It must be a string consisting
799	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1224	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
800	and the resulting module name is loaded and if the load was successful,	1225	and the resulting module name is loaded and if the load was successful,
801	used as event model. If it fails to load AnyEvent will proceed with	1226	used as event model. If it fails to load AnyEvent will proceed with
802	autodetection and -probing.	1227	auto detection and -probing.
803		1228
804	This functionality might change in future versions.	1229	This functionality might change in future versions.
805		1230
806	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1231	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
807	could start your program like this:	1232	could start your program like this:
808		1233
809	PERL_ANYEVENT_MODEL=Perl perl ...	1234	PERL_ANYEVENT_MODEL=Perl perl ...
		1235
		1236	=item C<PERL_ANYEVENT_PROTOCOLS>
		1237
		1238	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1239	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1240	of auto probing).
		1241
		1242	Must be set to a comma-separated list of protocols or address families,
		1243	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1244	used, and preference will be given to protocols mentioned earlier in the
		1245	list.
		1246
		1247	This variable can effectively be used for denial-of-service attacks
		1248	against local programs (e.g. when setuid), although the impact is likely
		1249	small, as the program has to handle connection errors already-
		1250
		1251	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1252	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1253	- only support IPv4, never try to resolve or contact IPv6
		1254	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1255	IPv6, but prefer IPv6 over IPv4.
		1256
		1257	=item C<PERL_ANYEVENT_EDNS0>
		1258
		1259	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1260	for DNS. This extension is generally useful to reduce DNS traffic, but
		1261	some (broken) firewalls drop such DNS packets, which is why it is off by
		1262	default.
		1263
		1264	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1265	EDNS0 in its DNS requests.
		1266
		1267	=item C<PERL_ANYEVENT_MAX_FORKS>
		1268
		1269	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1270	will create in parallel.
810		1271
811	=back	1272	=back
812		1273
813	=head1 EXAMPLE PROGRAM	1274	=head1 EXAMPLE PROGRAM
814		1275
…		…
825	poll => 'r',	1286	poll => 'r',
826	cb => sub {	1287	cb => sub {
827	warn "io event <$_[0]>\n"; # will always output <r>	1288	warn "io event <$_[0]>\n"; # will always output <r>
828	chomp (my $input = <STDIN>); # read a line	1289	chomp (my $input = <STDIN>); # read a line
829	warn "read: $input\n"; # output what has been read	1290	warn "read: $input\n"; # output what has been read
830	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1291	$cv->send if $input =~ /^q/i; # quit program if /^q/i
831	},	1292	},
832	);	1293	);
833		1294
834	my $time_watcher; # can only be used once	1295	my $time_watcher; # can only be used once
835		1296
…		…
840	});	1301	});
841	}	1302	}
842		1303
843	new_timer; # create first timer	1304	new_timer; # create first timer
844		1305
845	$cv->wait; # wait until user enters /^q/i	1306	$cv->recv; # wait until user enters /^q/i
846		1307
847	=head1 REAL-WORLD EXAMPLE	1308	=head1 REAL-WORLD EXAMPLE
848		1309
849	Consider the L<Net::FCP> module. It features (among others) the following	1310	Consider the L<Net::FCP> module. It features (among others) the following
850	API calls, which are to freenet what HTTP GET requests are to http:	1311	API calls, which are to freenet what HTTP GET requests are to http:
…		…
900	syswrite $txn->{fh}, $txn->{request}	1361	syswrite $txn->{fh}, $txn->{request}
901	or die "connection or write error";	1362	or die "connection or write error";
902	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1363	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
903		1364
904	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1365	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
905	result and signals any possible waiters that the request ahs finished:	1366	result and signals any possible waiters that the request has finished:
906		1367
907	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1368	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
908		1369
909	if (end-of-file or data complete) {	1370	if (end-of-file or data complete) {
910	$txn->{result} = $txn->{buf};	1371	$txn->{result} = $txn->{buf};
911	$txn->{finished}->broadcast;	1372	$txn->{finished}->send;
912	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1373	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
913	}	1374	}
914		1375
915	The C<result> method, finally, just waits for the finished signal (if the	1376	The C<result> method, finally, just waits for the finished signal (if the
916	request was already finished, it doesn't wait, of course, and returns the	1377	request was already finished, it doesn't wait, of course, and returns the
917	data:	1378	data:
918		1379
919	$txn->{finished}->wait;	1380	$txn->{finished}->recv;
920	return $txn->{result};	1381	return $txn->{result};
921		1382
922	The actual code goes further and collects all errors (C<die>s, exceptions)	1383	The actual code goes further and collects all errors (C<die>s, exceptions)
923	that occured during request processing. The C<result> method detects	1384	that occurred during request processing. The C<result> method detects
924	whether an exception as thrown (it is stored inside the $txn object)	1385	whether an exception as thrown (it is stored inside the $txn object)
925	and just throws the exception, which means connection errors and other	1386	and just throws the exception, which means connection errors and other
926	problems get reported tot he code that tries to use the result, not in a	1387	problems get reported tot he code that tries to use the result, not in a
927	random callback.	1388	random callback.
928		1389
…		…
959		1420
960	my $quit = AnyEvent->condvar;	1421	my $quit = AnyEvent->condvar;
961		1422
962	$fcp->txn_client_get ($url)->cb (sub {	1423	$fcp->txn_client_get ($url)->cb (sub {
963	...	1424	...
964	$quit->broadcast;	1425	$quit->send;
965	});	1426	});
966		1427
967	$quit->wait;	1428	$quit->recv;
968		1429
969		1430
970	=head1 BENCHMARKS	1431	=head1 BENCHMARKS
971		1432
972	To give you an idea of the performance and overheads that AnyEvent adds	1433	To give you an idea of the performance and overheads that AnyEvent adds
…		…
974	of various event loops I prepared some benchmarks.	1435	of various event loops I prepared some benchmarks.
975		1436
976	=head2 BENCHMARKING ANYEVENT OVERHEAD	1437	=head2 BENCHMARKING ANYEVENT OVERHEAD
977		1438
978	Here is a benchmark of various supported event models used natively and	1439	Here is a benchmark of various supported event models used natively and
979	through anyevent. The benchmark creates a lot of timers (with a zero	1440	through AnyEvent. The benchmark creates a lot of timers (with a zero
980	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	1441	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
981	which it is), lets them fire exactly once and destroys them again.	1442	which it is), lets them fire exactly once and destroys them again.
982		1443
983	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1444	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
984	distribution.	1445	distribution.
…		…
1001	all watchers, to avoid adding memory overhead. That means closure creation	1462	all watchers, to avoid adding memory overhead. That means closure creation
1002	and memory usage is not included in the figures.	1463	and memory usage is not included in the figures.
1003		1464
1004	I<invoke> is the time, in microseconds, used to invoke a simple	1465	I<invoke> is the time, in microseconds, used to invoke a simple
1005	callback. The callback simply counts down a Perl variable and after it was	1466	callback. The callback simply counts down a Perl variable and after it was
1006	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1467	invoked "watcher" times, it would C<< ->send >> a condvar once to
1007	signal the end of this phase.	1468	signal the end of this phase.
1008		1469
1009	I<destroy> is the time, in microseconds, that it takes to destroy a single	1470	I<destroy> is the time, in microseconds, that it takes to destroy a single
1010	watcher.	1471	watcher.
1011		1472
…		…
1107		1568
1108	=back	1569	=back
1109		1570
1110	=head2 BENCHMARKING THE LARGE SERVER CASE	1571	=head2 BENCHMARKING THE LARGE SERVER CASE
1111		1572
1112	This benchmark atcually benchmarks the event loop itself. It works by	1573	This benchmark actually benchmarks the event loop itself. It works by
1113	creating a number of "servers": each server consists of a socketpair, a	1574	creating a number of "servers": each server consists of a socket pair, a
1114	timeout watcher that gets reset on activity (but never fires), and an I/O	1575	timeout watcher that gets reset on activity (but never fires), and an I/O
1115	watcher waiting for input on one side of the socket. Each time the socket	1576	watcher waiting for input on one side of the socket. Each time the socket
1116	watcher reads a byte it will write that byte to a random other "server".	1577	watcher reads a byte it will write that byte to a random other "server".
1117		1578
1118	The effect is that there will be a lot of I/O watchers, only part of which	1579	The effect is that there will be a lot of I/O watchers, only part of which
1119	are active at any one point (so there is a constant number of active	1580	are active at any one point (so there is a constant number of active
1120	fds for each loop iterstaion, but which fds these are is random). The	1581	fds for each loop iteration, but which fds these are is random). The
1121	timeout is reset each time something is read because that reflects how	1582	timeout is reset each time something is read because that reflects how
1122	most timeouts work (and puts extra pressure on the event loops).	1583	most timeouts work (and puts extra pressure on the event loops).
1123		1584
1124	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1585	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1125	(1%) are active. This mirrors the activity of large servers with many	1586	(1%) are active. This mirrors the activity of large servers with many
1126	connections, most of which are idle at any one point in time.	1587	connections, most of which are idle at any one point in time.
1127		1588
1128	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1589	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1129	distribution.	1590	distribution.
…		…
1131	=head3 Explanation of the columns	1592	=head3 Explanation of the columns
1132		1593
1133	I<sockets> is the number of sockets, and twice the number of "servers" (as	1594	I<sockets> is the number of sockets, and twice the number of "servers" (as
1134	each server has a read and write socket end).	1595	each server has a read and write socket end).
1135		1596
1136	I<create> is the time it takes to create a socketpair (which is	1597	I<create> is the time it takes to create a socket pair (which is
1137	nontrivial) and two watchers: an I/O watcher and a timeout watcher.	1598	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1138		1599
1139	I<request>, the most important value, is the time it takes to handle a	1600	I<request>, the most important value, is the time it takes to handle a
1140	single "request", that is, reading the token from the pipe and forwarding	1601	single "request", that is, reading the token from the pipe and forwarding
1141	it to another server. This includes deleting the old timeout and creating	1602	it to another server. This includes deleting the old timeout and creating
…		…
1214	speed most when you have lots of watchers, not when you only have a few of	1675	speed most when you have lots of watchers, not when you only have a few of
1215	them).	1676	them).
1216		1677
1217	EV is again fastest.	1678	EV is again fastest.
1218		1679
1219	Perl again comes second. It is noticably faster than the C-based event	1680	Perl again comes second. It is noticeably faster than the C-based event
1220	loops Event and Glib, although the difference is too small to really	1681	loops Event and Glib, although the difference is too small to really
1221	matter.	1682	matter.
1222		1683
1223	POE also performs much better in this case, but is is still far behind the	1684	POE also performs much better in this case, but is is still far behind the
1224	others.	1685	others.
…		…
1253	specified in the variable.	1714	specified in the variable.
1254		1715
1255	You can make AnyEvent completely ignore this variable by deleting it	1716	You can make AnyEvent completely ignore this variable by deleting it
1256	before the first watcher gets created, e.g. with a C<BEGIN> block:	1717	before the first watcher gets created, e.g. with a C<BEGIN> block:
1257		1718
1258	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1719	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1259		1720
1260	use AnyEvent;	1721	use AnyEvent;
		1722
		1723	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
		1724	be used to probe what backend is used and gain other information (which is
		1725	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1726	$ENV{PERL_ANYEGENT_STRICT}.
		1727
		1728
		1729	=head1 BUGS
		1730
		1731	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		1732	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		1733	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		1734	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as
		1735	pronounced).
1261		1736
1262		1737
1263	=head1 SEE ALSO	1738	=head1 SEE ALSO
1264		1739
1265	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,	1740	Utility functions: L<AnyEvent::Util>.
1266	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,	1741
		1742	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1267	L<Event::Lib>, L<Qt>, L<POE>.	1743	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1268		1744
1269	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,	1745	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1270	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,	1746	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1271	L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>,	1747	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1272	L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>.	1748	L<AnyEvent::Impl::POE>.
1273		1749
		1750	Non-blocking file handles, sockets, TCP clients and
		1751	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1752
		1753	Asynchronous DNS: L<AnyEvent::DNS>.
		1754
		1755	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
		1756
1274	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1757	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1275		1758
1276		1759
1277	=head1 AUTHOR	1760	=head1 AUTHOR
1278		1761
1279	Marc Lehmann <schmorp@schmorp.de>	1762	Marc Lehmann <schmorp@schmorp.de>
1280	http://home.schmorp.de/	1763	http://home.schmorp.de/
1281		1764
1282	=cut	1765	=cut
1283		1766
1284	1	1767	1
1285		1768

Diff Legend

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

Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.104 by root, Wed Apr 30 11:40:22 2008 UTC vs. Revision 1.172 by root, Thu Jul 17 15:21:02 2008 UTC

Diff Legend

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.104 by root, Wed Apr 30 11:40:22 2008 UTC vs.
Revision 1.172 by root, Thu Jul 17 15:21:02 2008 UTC