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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.110 by root, Sat May 10 00:57:31 2008 UTC vs.
Revision 1.171 by root, Wed Jul 16 21:17:59 2008 UTC

…		…
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 ->send	21	$w->recv; # enters "main loop" till $condvar gets ->send
21	$w->send; # 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
…		…
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->send;	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
302	If you are familiar with some event loops you will know that all of them	374	If you are familiar with some event loops you will know that all of them
303	require you to run some blocking "loop", "run" or similar function that	375	require you to run some blocking "loop", "run" or similar function that
…		…
312	Condition variables can be created by calling the C<< AnyEvent->condvar	384	Condition variables can be created by calling the C<< AnyEvent->condvar
313	>> method, usually without arguments. The only argument pair allowed is	385	>> method, usually without arguments. The only argument pair allowed is
314	C<cb>, which specifies a callback to be called when the condition variable	386	C<cb>, which specifies a callback to be called when the condition variable
315	becomes true.	387	becomes true.
316		388
317	After creation, the conditon variable is "false" until it becomes "true"	389	After creation, the condition variable is "false" until it becomes "true"
318	by calling the C<send> method.	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).
319		393
320	Condition variables are similar to callbacks, except that you can	394	Condition variables are similar to callbacks, except that you can
321	optionally wait for them. They can also be called merge points - points	395	optionally wait for them. They can also be called merge points - points
322	in time where multiple outstandign events have been processed. And yet	396	in time where multiple outstanding events have been processed. And yet
323	another way to call them is transations - each condition variable can be	397	another way to call them is transactions - each condition variable can be
324	used to represent a transaction, which finishes at some point and delivers	398	used to represent a transaction, which finishes at some point and delivers
325	a result.	399	a result.
326		400
327	Condition variables are very useful to signal that something has finished,	401	Condition variables are very useful to signal that something has finished,
328	for example, if you write a module that does asynchronous http requests,	402	for example, if you write a module that does asynchronous http requests,
329	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
330	availability of results. The user can either act when the callback is	404	availability of results. The user can either act when the callback is
331	called or can synchronously C<< ->wait >> for the results.	405	called or can synchronously C<< ->recv >> for the results.
332		406
333	You can also use them to simulate traditional event loops - for example,	407	You can also use them to simulate traditional event loops - for example,
334	you can block your main program until an event occurs - for example, you	408	you can block your main program until an event occurs - for example, you
335	could C<< ->wait >> in your main program until the user clicks the Quit	409	could C<< ->recv >> in your main program until the user clicks the Quit
336	button of your app, which would C<< ->send >> the "quit" event.	410	button of your app, which would C<< ->send >> the "quit" event.
337		411
338	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
339	two pieces 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
340	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
341	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,
342	as this asks for trouble.	416	as this asks for trouble.
343		417
344	Condition variables are represented by hash refs in perl, and the keys	418	Condition variables are represented by hash refs in perl, and the keys
…		…
349		423
350	There are two "sides" to a condition variable - the "producer side" which	424	There are two "sides" to a condition variable - the "producer side" which
351	eventually calls C<< -> send >>, and the "consumer side", which waits	425	eventually calls C<< -> send >>, and the "consumer side", which waits
352	for the send to occur.	426	for the send to occur.
353		427
354	Example:	428	Example: wait for a timer.
355		429
356	# wait till the result is ready	430	# wait till the result is ready
357	my $result_ready = AnyEvent->condvar;	431	my $result_ready = AnyEvent->condvar;
358		432
359	# do something such as adding a timer	433	# do something such as adding a timer
…		…
365	cb => sub { $result_ready->send },	439	cb => sub { $result_ready->send },
366	);	440	);
367		441
368	# this "blocks" (while handling events) till the callback	442	# this "blocks" (while handling events) till the callback
369	# calls send	443	# calls send
370	$result_ready->wait;	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;
371		452
372	=head3 METHODS FOR PRODUCERS	453	=head3 METHODS FOR PRODUCERS
373		454
374	These methods should only be used by the producing side, i.e. the	455	These methods should only be used by the producing side, i.e. the
375	code/module that eventually sends the signal. Note that it is also	456	code/module that eventually sends the signal. Note that it is also
…		…
378		459
379	=over 4	460	=over 4
380		461
381	=item $cv->send (...)	462	=item $cv->send (...)
382		463
383	Flag the condition as ready - a running C<< ->wait >> and all further	464	Flag the condition as ready - a running C<< ->recv >> and all further
384	calls to C<wait> will (eventually) return after this method has been	465	calls to C<recv> will (eventually) return after this method has been
385	called. If nobody is waiting the send will be remembered.	466	called. If nobody is waiting the send will be remembered.
386		467
387	If a callback has been set on the condition variable, it is called	468	If a callback has been set on the condition variable, it is called
388	immediately from within send.	469	immediately from within send.
389		470
390	Any arguments passed to the C<send> call will be returned by all	471	Any arguments passed to the C<send> call will be returned by all
391	future C<< ->wait >> calls.	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).
392		482
393	=item $cv->croak ($error)	483	=item $cv->croak ($error)
394		484
395	Similar to send, but causes all call's wait C<< ->wait >> to invoke	485	Similar to send, but causes all call's to C<< ->recv >> to invoke
396	C<Carp::croak> with the given error message/object/scalar.	486	C<Carp::croak> with the given error message/object/scalar.
397		487
398	This can be used to signal any errors to the condition variable	488	This can be used to signal any errors to the condition variable
399	user/consumer.	489	user/consumer.
400		490
401	=item $cv->begin ([group callback])	491	=item $cv->begin ([group callback])
402		492
403	=item $cv->end	493	=item $cv->end
		494
		495	These two methods are EXPERIMENTAL and MIGHT CHANGE.
404		496
405	These two methods can be used to combine many transactions/events into	497	These two methods can be used to combine many transactions/events into
406	one. For example, a function that pings many hosts in parallel might want	498	one. For example, a function that pings many hosts in parallel might want
407	to use a condition variable for the whole process.	499	to use a condition variable for the whole process.
408		500
…		…
443	doesn't execute once).	535	doesn't execute once).
444		536
445	This is the general pattern when you "fan out" into multiple subrequests:	537	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>	538	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	539	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>.	540	C<begin> and for each subrequest you finish, call C<end>.
449		541
450	=back	542	=back
451		543
452	=head3 METHODS FOR CONSUMERS	544	=head3 METHODS FOR CONSUMERS
453		545
454	These methods should only be used by the consuming side, i.e. the	546	These methods should only be used by the consuming side, i.e. the
455	code awaits the condition.	547	code awaits the condition.
456		548
457	=over 4	549	=over 4
458		550
459	=item $cv->wait	551	=item $cv->recv
460		552
461	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	553	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
462	>> methods have been called on c<$cv>, while servicing other watchers	554	>> methods have been called on c<$cv>, while servicing other watchers
463	normally.	555	normally.
464		556
…		…
475	(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
476	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
477	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
478	condition variables with some kind of request results and supporting	570	condition variables with some kind of request results and supporting
479	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,
480	while still suppporting blocking waits if the caller so desires).	572	while still supporting blocking waits if the caller so desires).
481		573
482	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
483	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
484	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	576	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
485	can supply.	577	can supply.
486		578
487	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in	579	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
488	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe	580	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
489	versions and also integrates coroutines into AnyEvent, making blocking	581	versions and also integrates coroutines into AnyEvent, making blocking
490	C<< ->wait >> calls perfectly safe as long as they are done from another	582	C<< ->recv >> calls perfectly safe as long as they are done from another
491	coroutine (one that doesn't run the event loop).	583	coroutine (one that doesn't run the event loop).
492		584
493	You can ensure that C<< -wait >> never blocks by setting a callback and	585	You can ensure that C<< -recv >> never blocks by setting a callback and
494	only calling C<< ->wait >> from within that callback (or at a later	586	only calling C<< ->recv >> from within that callback (or at a later
495	time). This will work even when the event loop does not support blocking	587	time). This will work even when the event loop does not support blocking
496	waits otherwise.	588	waits otherwise.
497		589
498	=item $bool = $cv->ready	590	=item $bool = $cv->ready
499		591
…		…
504		596
505	This is a mutator function that returns the callback set and optionally	597	This is a mutator function that returns the callback set and optionally
506	replaces it before doing so.	598	replaces it before doing so.
507		599
508	The callback will be called when the condition becomes "true", i.e. when	600	The callback will be called when the condition becomes "true", i.e. when
509	C<send> or C<croak> are called. Calling C<wait> inside the callback	601	C<send> or C<croak> are called, with the only argument being the condition
510	or at any later time is guaranteed not to block.	602	variable itself. Calling C<recv> inside the callback or at any later time
		603	is guaranteed not to block.
511		604
512	=back	605	=back
513		606
514	=head1 GLOBAL VARIABLES AND FUNCTIONS	607	=head1 GLOBAL VARIABLES AND FUNCTIONS
515		608
…		…
549	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	642	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
550	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
551	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
552	runtime.	645	runtime.
553		646
554	=item $guard = AnyEvent::on_detect { BLOCK }	647	=item $guard = AnyEvent::post_detect { BLOCK }
555		648
556	Arranges for the code block to be executed as soon as the event model is	649	Arranges for the code block to be executed as soon as the event model is
557	autodetected (or immediately if this has already happened).	650	autodetected (or immediately if this has already happened).
558		651
559	If called in scalar or list context, then it creates and returns an object	652	If called in scalar or list context, then it creates and returns an object
560	that automatically removes the callback again when it is destroyed.	653	that automatically removes the callback again when it is destroyed. See
		654	L<Coro::BDB> for a case where this is useful.
561		655
562	=item @AnyEvent::on_detect	656	=item @AnyEvent::post_detect
563		657
564	If there are any code references in this array (you can C<push> to it	658	If there are any code references in this array (you can C<push> to it
565	before or after loading AnyEvent), then they will called directly after	659	before or after loading AnyEvent), then they will called directly after
566	the event loop has been chosen.	660	the event loop has been chosen.
567		661
568	You should check C<$AnyEvent::MODEL> before adding to this array, though:	662	You should check C<$AnyEvent::MODEL> before adding to this array, though:
569	if it contains a true value then the event loop has already been detected,	663	if it contains a true value then the event loop has already been detected,
570	and the array will be ignored.	664	and the array will be ignored.
571		665
572	Best use C<AnyEvent::on_detect { BLOCK }> instead.	666	Best use C<AnyEvent::post_detect { BLOCK }> instead.
573		667
574	=back	668	=back
575		669
576	=head1 WHAT TO DO IN A MODULE	670	=head1 WHAT TO DO IN A MODULE
577		671
…		…
581	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
582	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
583	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
584	to load the event module first.	678	to load the event module first.
585		679
586	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
587	the C<< ->send >> method has been called on it already. This is	681	the C<< ->send >> method has been called on it already. This is
588	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
589	events is to stay interactive.	683	events is to stay interactive.
590		684
591	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
592	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
593	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 >>
594	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).
595		689
596	=head1 WHAT TO DO IN THE MAIN PROGRAM	690	=head1 WHAT TO DO IN THE MAIN PROGRAM
597		691
598	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
…		…
600		694
601	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
602	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
603	decide which implementation to chose if some module relies on it.	697	decide which implementation to chose if some module relies on it.
604		698
605	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
606	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
607	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
608	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
609	modules might create watchers when they are loaded, and AnyEvent will	703	modules might create watchers when they are loaded, and AnyEvent will
610	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
611	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.
612		706
613	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
614	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	708	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
615	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
616		727
617	=head1 OTHER MODULES	728	=head1 OTHER MODULES
618		729
619	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
620	AnyEvent and can therefore be mixed easily with other AnyEvent modules	731	AnyEvent and can therefore be mixed easily with other AnyEvent modules
…		…
626	=item L<AnyEvent::Util>	737	=item L<AnyEvent::Util>
627		738
628	Contains various utility functions that replace often-used but blocking	739	Contains various utility functions that replace often-used but blocking
629	functions such as C<inet_aton> by event-/callback-based versions.	740	functions such as C<inet_aton> by event-/callback-based versions.
630		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
631	=item L<AnyEvent::Handle>	748	=item L<AnyEvent::Handle>
632		749
633	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.
634		753
635	=item L<AnyEvent::Socket>	754	=item L<AnyEvent::DNS>
636		755
637	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.
638		762
639	=item L<AnyEvent::HTTPD>	763	=item L<AnyEvent::HTTPD>
640		764
641	Provides a simple web application server framework.	765	Provides a simple web application server framework.
642		766
643	=item L<AnyEvent::DNS>
644
645	Provides asynchronous DNS resolver capabilities, beyond what
646	L<AnyEvent::Util> offers.
647
648	=item L<AnyEvent::FastPing>	767	=item L<AnyEvent::FastPing>
649		768
650	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>).
651		794
652	=item L<Net::IRC3>	795	=item L<Net::IRC3>
653		796
654	AnyEvent based IRC client module family.	797	AnyEvent based IRC client module family.
655		798
…		…
672		815
673	=item L<IO::Lambda>	816	=item L<IO::Lambda>
674		817
675	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.
676		819
677	=item L<IO::AIO>
678
679	Truly asynchronous I/O, should be in the toolbox of every event
680	programmer. Can be trivially made to use AnyEvent.
681
682	=item L<BDB>
683
684	Truly asynchronous Berkeley DB access. Can be trivially made to use
685	AnyEvent.
686
687	=back	820	=back
688		821
689	=cut	822	=cut
690		823
691	package AnyEvent;	824	package AnyEvent;
…		…
693	no warnings;	826	no warnings;
694	use strict;	827	use strict;
695		828
696	use Carp;	829	use Carp;
697		830
698	our $VERSION = '3.4';	831	our $VERSION = 4.21;
699	our $MODEL;	832	our $MODEL;
700		833
701	our $AUTOLOAD;	834	our $AUTOLOAD;
702	our @ISA;	835	our @ISA;
703		836
		837	our @REGISTRY;
		838
		839	our $WIN32;
		840
		841	BEGIN {
		842	my $win32 = ! ! ($^O =~ /mswin32/i);
		843	eval "sub WIN32(){ $win32 }";
		844	}
		845
704	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	846	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
705		847
706	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	$ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
		855	}
707		856
708	my @models = (	857	my @models = (
709	[EV:: => AnyEvent::Impl::EV::],	858	[EV:: => AnyEvent::Impl::EV::],
710	[Event:: => AnyEvent::Impl::Event::],	859	[Event:: => AnyEvent::Impl::Event::],
711	[Tk:: => AnyEvent::Impl::Tk::],
712	[Wx:: => AnyEvent::Impl::POE::],
713	[Prima:: => AnyEvent::Impl::POE::],
714	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	860	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
715	# everything below here will not be autoprobed as the pureperl backend should work everywhere	861	# everything below here will not be autoprobed
716	[Glib:: => AnyEvent::Impl::Glib::],	862	# as the pureperl backend should work everywhere
		863	# and is usually faster
		864	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		865	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
717	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	866	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
718	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	867	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
719	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	868	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
		869	[Wx:: => AnyEvent::Impl::POE::],
		870	[Prima:: => AnyEvent::Impl::POE::],
720	);	871	);
721		872
722	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);	873	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
723		874
724	our @on_detect;	875	our @post_detect;
725		876
726	sub on_detect(&) {	877	sub post_detect(&) {
727	my ($cb) = @_;	878	my ($cb) = @_;
728		879
729	if ($MODEL) {	880	if ($MODEL) {
730	$cb->();	881	$cb->();
731		882
732	1	883	1
733	} else {	884	} else {
734	push @on_detect, $cb;	885	push @post_detect, $cb;
735		886
736	defined wantarray	887	defined wantarray
737	? bless \$cb, "AnyEvent::Util::Guard"	888	? bless \$cb, "AnyEvent::Util::PostDetect"
738	: ()	889	: ()
739	}	890	}
740	}	891	}
741		892
742	sub AnyEvent::Util::Guard::DESTROY {	893	sub AnyEvent::Util::PostDetect::DESTROY {
743	@on_detect = grep $_ != ${$_[0]}, @on_detect;	894	@post_detect = grep $_ != ${$_[0]}, @post_detect;
744	}	895	}
745		896
746	sub detect() {	897	sub detect() {
747	unless ($MODEL) {	898	unless ($MODEL) {
748	no strict 'refs';	899	no strict 'refs';
		900	local $SIG{__DIE__};
749		901
750	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	902	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
751	my $model = "AnyEvent::Impl::$1";	903	my $model = "AnyEvent::Impl::$1";
752	if (eval "require $model") {	904	if (eval "require $model") {
753	$MODEL = $model;	905	$MODEL = $model;
…		…
787	$MODEL	939	$MODEL
788	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	940	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
789	}	941	}
790	}	942	}
791		943
		944	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		945
792	unshift @ISA, $MODEL;	946	unshift @ISA, $MODEL;
793	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
794		947
		948	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		949
795	(shift @on_detect)->() while @on_detect;	950	(shift @post_detect)->() while @post_detect;
796	}	951	}
797		952
798	$MODEL	953	$MODEL
799	}	954	}
800		955
…		…
808		963
809	my $class = shift;	964	my $class = shift;
810	$class->$func (@_);	965	$class->$func (@_);
811	}	966	}
812		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
813	package AnyEvent::Base;	989	package AnyEvent::Base;
814		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
815	# default implementation for ->condvar, ->wait, ->broadcast	998	# default implementation for ->condvar
816		999
817	sub condvar {	1000	sub condvar {
818	bless \my $flag, "AnyEvent::Base::CondVar"	1001	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
819	}
820
821	sub AnyEvent::Base::CondVar::broadcast {
822	${$_[0]}++;
823	}
824
825	sub AnyEvent::Base::CondVar::wait {
826	AnyEvent->one_event while !${$_[0]};
827	}	1002	}
828		1003
829	# default implementation for ->signal	1004	# default implementation for ->signal
830		1005
831	our %SIG_CB;	1006	our %SIG_CB;
…		…
847	sub AnyEvent::Base::Signal::DESTROY {	1022	sub AnyEvent::Base::Signal::DESTROY {
848	my ($signal, $cb) = @{$_[0]};	1023	my ($signal, $cb) = @{$_[0]};
849		1024
850	delete $SIG_CB{$signal}{$cb};	1025	delete $SIG_CB{$signal}{$cb};
851		1026
852	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1027	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
853	}	1028	}
854		1029
855	# default implementation for ->child	1030	# default implementation for ->child
856		1031
857	our %PID_CB;	1032	our %PID_CB;
…		…
884	or Carp::croak "required option 'pid' is missing";	1059	or Carp::croak "required option 'pid' is missing";
885		1060
886	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1061	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
887		1062
888	unless ($WNOHANG) {	1063	unless ($WNOHANG) {
889	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } \|\| 1;	1064	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
890	}	1065	}
891		1066
892	unless ($CHLD_W) {	1067	unless ($CHLD_W) {
893	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1068	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
894	# 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
…		…
904	delete $PID_CB{$pid}{$cb};	1079	delete $PID_CB{$pid}{$cb};
905	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1080	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
906		1081
907	undef $CHLD_W unless keys %PID_CB;	1082	undef $CHLD_W unless keys %PID_CB;
908	}	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;
909		1144
910	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1145	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
911		1146
912	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
913	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
…		…
967	C<PERL_ANYEVENT_MODEL>.	1202	C<PERL_ANYEVENT_MODEL>.
968		1203
969	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
970	model it chooses.	1205	model it chooses.
971		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
972	=item C<PERL_ANYEVENT_MODEL>	1220	=item C<PERL_ANYEVENT_MODEL>
973		1221
974	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
975	autodetection and -probing kicks in. It must be a string consisting	1223	auto detection and -probing kicks in. It must be a string consisting
976	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1224	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
977	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,
978	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
979	autodetection and -probing.	1227	auto detection and -probing.
980		1228
981	This functionality might change in future versions.	1229	This functionality might change in future versions.
982		1230
983	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
984	could start your program like this:	1232	could start your program like this:
985		1233
986	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.
987		1271
988	=back	1272	=back
989		1273
990	=head1 EXAMPLE PROGRAM	1274	=head1 EXAMPLE PROGRAM
991		1275
…		…
1002	poll => 'r',	1286	poll => 'r',
1003	cb => sub {	1287	cb => sub {
1004	warn "io event <$_[0]>\n"; # will always output <r>	1288	warn "io event <$_[0]>\n"; # will always output <r>
1005	chomp (my $input = <STDIN>); # read a line	1289	chomp (my $input = <STDIN>); # read a line
1006	warn "read: $input\n"; # output what has been read	1290	warn "read: $input\n"; # output what has been read
1007	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1291	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1008	},	1292	},
1009	);	1293	);
1010		1294
1011	my $time_watcher; # can only be used once	1295	my $time_watcher; # can only be used once
1012		1296
…		…
1017	});	1301	});
1018	}	1302	}
1019		1303
1020	new_timer; # create first timer	1304	new_timer; # create first timer
1021		1305
1022	$cv->wait; # wait until user enters /^q/i	1306	$cv->recv; # wait until user enters /^q/i
1023		1307
1024	=head1 REAL-WORLD EXAMPLE	1308	=head1 REAL-WORLD EXAMPLE
1025		1309
1026	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
1027	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:
…		…
1077	syswrite $txn->{fh}, $txn->{request}	1361	syswrite $txn->{fh}, $txn->{request}
1078	or die "connection or write error";	1362	or die "connection or write error";
1079	$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 });
1080		1364
1081	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
1082	result and signals any possible waiters that the request ahs finished:	1366	result and signals any possible waiters that the request has finished:
1083		1367
1084	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1368	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1085		1369
1086	if (end-of-file or data complete) {	1370	if (end-of-file or data complete) {
1087	$txn->{result} = $txn->{buf};	1371	$txn->{result} = $txn->{buf};
1088	$txn->{finished}->broadcast;	1372	$txn->{finished}->send;
1089	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1373	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
1090	}	1374	}
1091		1375
1092	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
1093	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
1094	data:	1378	data:
1095		1379
1096	$txn->{finished}->wait;	1380	$txn->{finished}->recv;
1097	return $txn->{result};	1381	return $txn->{result};
1098		1382
1099	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)
1100	that occured during request processing. The C<result> method detects	1384	that occurred during request processing. The C<result> method detects
1101	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)
1102	and just throws the exception, which means connection errors and other	1386	and just throws the exception, which means connection errors and other
1103	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
1104	random callback.	1388	random callback.
1105		1389
…		…
1136		1420
1137	my $quit = AnyEvent->condvar;	1421	my $quit = AnyEvent->condvar;
1138		1422
1139	$fcp->txn_client_get ($url)->cb (sub {	1423	$fcp->txn_client_get ($url)->cb (sub {
1140	...	1424	...
1141	$quit->broadcast;	1425	$quit->send;
1142	});	1426	});
1143		1427
1144	$quit->wait;	1428	$quit->recv;
1145		1429
1146		1430
1147	=head1 BENCHMARKS	1431	=head1 BENCHMARKS
1148		1432
1149	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
…		…
1151	of various event loops I prepared some benchmarks.	1435	of various event loops I prepared some benchmarks.
1152		1436
1153	=head2 BENCHMARKING ANYEVENT OVERHEAD	1437	=head2 BENCHMARKING ANYEVENT OVERHEAD
1154		1438
1155	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
1156	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
1157	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,
1158	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.
1159		1443
1160	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
1161	distribution.	1445	distribution.
…		…
1178	all watchers, to avoid adding memory overhead. That means closure creation	1462	all watchers, to avoid adding memory overhead. That means closure creation
1179	and memory usage is not included in the figures.	1463	and memory usage is not included in the figures.
1180		1464
1181	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
1182	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
1183	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1467	invoked "watcher" times, it would C<< ->send >> a condvar once to
1184	signal the end of this phase.	1468	signal the end of this phase.
1185		1469
1186	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
1187	watcher.	1471	watcher.
1188		1472
…		…
1284		1568
1285	=back	1569	=back
1286		1570
1287	=head2 BENCHMARKING THE LARGE SERVER CASE	1571	=head2 BENCHMARKING THE LARGE SERVER CASE
1288		1572
1289	This benchmark atcually benchmarks the event loop itself. It works by	1573	This benchmark actually benchmarks the event loop itself. It works by
1290	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
1291	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
1292	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
1293	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".
1294		1578
1295	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
1296	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
1297	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
1298	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
1299	most timeouts work (and puts extra pressure on the event loops).	1583	most timeouts work (and puts extra pressure on the event loops).
1300		1584
1301	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
1302	(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
1303	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.
1304		1588
1305	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
1306	distribution.	1590	distribution.
…		…
1308	=head3 Explanation of the columns	1592	=head3 Explanation of the columns
1309		1593
1310	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
1311	each server has a read and write socket end).	1595	each server has a read and write socket end).
1312		1596
1313	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
1314	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.
1315		1599
1316	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
1317	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
1318	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
…		…
1391	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
1392	them).	1676	them).
1393		1677
1394	EV is again fastest.	1678	EV is again fastest.
1395		1679
1396	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
1397	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
1398	matter.	1682	matter.
1399		1683
1400	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
1401	others.	1685	others.
…		…
1430	specified in the variable.	1714	specified in the variable.
1431		1715
1432	You can make AnyEvent completely ignore this variable by deleting it	1716	You can make AnyEvent completely ignore this variable by deleting it
1433	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:
1434		1718
1435	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1719	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1436		1720
1437	use AnyEvent;	1721	use AnyEvent;
1438		1722
1439	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1723	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1440	be used to probe what backend is used and gain other information (which is	1724	be used to probe what backend is used and gain other information (which is
1441	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	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).
1442		1736
1443		1737
1444	=head1 SEE ALSO	1738	=head1 SEE ALSO
		1739
		1740	Utility functions: L<AnyEvent::Util>.
1445		1741
1446	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	1742	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1447	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	1743	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1448		1744
1449	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	1745	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1450	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	1746	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1451	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	1747	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1452	L<AnyEvent::Impl::POE>.	1748	L<AnyEvent::Impl::POE>.
1453		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
1454	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	1755	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
1455		1756
1456	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1757	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1457		1758
1458		1759
1459	=head1 AUTHOR	1760	=head1 AUTHOR
1460		1761
1461	Marc Lehmann <schmorp@schmorp.de>	1762	Marc Lehmann <schmorp@schmorp.de>
1462	http://home.schmorp.de/	1763	http://home.schmorp.de/
1463		1764
1464	=cut	1765	=cut
1465		1766
1466	1	1767	1
1467		1768

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.110 by root, Sat May 10 00:57:31 2008 UTC vs.
Revision 1.171 by root, Wed Jul 16 21:17:59 2008 UTC