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Revision 1.109 by root, Sat May 10 00:45:18 2008 UTC vs.
Revision 1.199 by root, Fri Mar 27 10:49:50 2009 UTC

…		…
6		6
7	=head1 SYNOPSIS	7	=head1 SYNOPSIS
8		8
9	use AnyEvent;	9	use AnyEvent;
10		10
11	my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub {	11	my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { ... });
		12
		13	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
		14	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
		15
		16	print AnyEvent->now; # prints current event loop time
		17	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
		18
		19	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
		20
		21	my $w = AnyEvent->child (pid => $pid, cb => sub {
		22	my ($pid, $status) = @_;
12	...	23	...
13	});	24	});
14		25
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {
16	...
17	});
18
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	26	my $w = AnyEvent->condvar; # stores whether a condition was flagged
		27	$w->send; # wake up current and all future recv's
20	$w->wait; # enters "main loop" till $condvar gets ->send	28	$w->recv; # enters "main loop" till $condvar gets ->send
21	$w->send; # wake up current and all future wait's	29	# use a condvar in callback mode:
		30	$w->cb (sub { $_[0]->recv });
		31
		32	=head1 INTRODUCTION/TUTORIAL
		33
		34	This manpage is mainly a reference manual. If you are interested
		35	in a tutorial or some gentle introduction, have a look at the
		36	L<AnyEvent::Intro> manpage.
22		37
23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	38	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24		39
25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	40	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26	nowadays. So what is different about AnyEvent?	41	nowadays. So what is different about AnyEvent?
27		42
28	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of	43	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
29	policy> and AnyEvent is I<small and efficient>.	44	policy> and AnyEvent is I<small and efficient>.
30		45
31	First and foremost, I<AnyEvent is not an event model> itself, it only	46	First and foremost, I<AnyEvent is not an event model> itself, it only
32	interfaces to whatever event model the main program happens to use in a	47	interfaces to whatever event model the main program happens to use, in a
33	pragmatic way. For event models and certain classes of immortals alike,	48	pragmatic way. For event models and certain classes of immortals alike,
34	the statement "there can only be one" is a bitter reality: In general,	49	the statement "there can only be one" is a bitter reality: In general,
35	only one event loop can be active at the same time in a process. AnyEvent	50	only one event loop can be active at the same time in a process. AnyEvent
36	helps hiding the differences between those event loops.	51	cannot change this, but it can hide the differences between those event
		52	loops.
37		53
38	The goal of AnyEvent is to offer module authors the ability to do event	54	The goal of AnyEvent is to offer module authors the ability to do event
39	programming (waiting for I/O or timer events) without subscribing to a	55	programming (waiting for I/O or timer events) without subscribing to a
40	religion, a way of living, and most importantly: without forcing your	56	religion, a way of living, and most importantly: without forcing your
41	module users into the same thing by forcing them to use the same event	57	module users into the same thing by forcing them to use the same event
42	model you use.	58	model you use.
43		59
44	For modules like POE or IO::Async (which is a total misnomer as it is	60	For modules like POE or IO::Async (which is a total misnomer as it is
45	actually doing all I/O I<synchronously>...), using them in your module is	61	actually doing all I/O I<synchronously>...), using them in your module is
46	like joining a cult: After you joined, you are dependent on them and you	62	like joining a cult: After you joined, you are dependent on them and you
47	cannot use anything else, as it is simply incompatible to everything that	63	cannot use anything else, as they are simply incompatible to everything
48	isn't itself. What's worse, all the potential users of your module are	64	that isn't them. What's worse, all the potential users of your
49	I<also> forced to use the same event loop you use.	65	module are I<also> forced to use the same event loop you use.
50		66
51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	67	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	68	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
53	with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if	69	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
54	your module uses one of those, every user of your module has to use it,	70	your module uses one of those, every user of your module has to use it,
55	too. But if your module uses AnyEvent, it works transparently with all	71	too. But if your module uses AnyEvent, it works transparently with all
56	event models it supports (including stuff like POE and IO::Async, as long	72	event models it supports (including stuff like IO::Async, as long as those
57	as those use one of the supported event loops. It is trivial to add new	73	use one of the supported event loops. It is trivial to add new event loops
58	event loops to AnyEvent, too, so it is future-proof).	74	to AnyEvent, too, so it is future-proof).
59		75
60	In addition to being free of having to use I<the one and only true event	76	In addition to being free of having to use I<the one and only true event
61	model>, AnyEvent also is free of bloat and policy: with POE or similar	77	model>, AnyEvent also is free of bloat and policy: with POE or similar
62	modules, you get an enourmous amount of code and strict rules you have to	78	modules, you get an enormous amount of code and strict rules you have to
63	follow. AnyEvent, on the other hand, is lean and up to the point, by only	79	follow. AnyEvent, on the other hand, is lean and up to the point, by only
64	offering the functionality that is necessary, in as thin as a wrapper as	80	offering the functionality that is necessary, in as thin as a wrapper as
65	technically possible.	81	technically possible.
66		82
		83	Of course, AnyEvent comes with a big (and fully optional!) toolbox
		84	of useful functionality, such as an asynchronous DNS resolver, 100%
		85	non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
		86	such as Windows) and lots of real-world knowledge and workarounds for
		87	platform bugs and differences.
		88
67	Of course, if you want lots of policy (this can arguably be somewhat	89	Now, if you I<do want> lots of policy (this can arguably be somewhat
68	useful) and you want to force your users to use the one and only event	90	useful) and you want to force your users to use the one and only event
69	model, you should I<not> use this module.	91	model, you should I<not> use this module.
70		92
71	=head1 DESCRIPTION	93	=head1 DESCRIPTION
72		94
…		…
102	starts using it, all bets are off. Maybe you should tell their authors to	124	starts using it, all bets are off. Maybe you should tell their authors to
103	use AnyEvent so their modules work together with others seamlessly...	125	use AnyEvent so their modules work together with others seamlessly...
104		126
105	The pure-perl implementation of AnyEvent is called	127	The pure-perl implementation of AnyEvent is called
106	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	128	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
107	explicitly.	129	explicitly and enjoy the high availability of that event loop :)
108		130
109	=head1 WATCHERS	131	=head1 WATCHERS
110		132
111	AnyEvent has the central concept of a I<watcher>, which is an object that	133	AnyEvent has the central concept of a I<watcher>, which is an object that
112	stores relevant data for each kind of event you are waiting for, such as	134	stores relevant data for each kind of event you are waiting for, such as
113	the callback to call, the filehandle to watch, etc.	135	the callback to call, the file handle to watch, etc.
114		136
115	These watchers are normal Perl objects with normal Perl lifetime. After	137	These watchers are normal Perl objects with normal Perl lifetime. After
116	creating a watcher it will immediately "watch" for events and invoke the	138	creating a watcher it will immediately "watch" for events and invoke the
117	callback when the event occurs (of course, only when the event model	139	callback when the event occurs (of course, only when the event model
118	is in control).	140	is in control).
119		141
		142	Note that B<callbacks must not permanently change global variables>
		143	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
		144	callbacks must not C<die> >>. The former is good programming practise in
		145	Perl and the latter stems from the fact that exception handling differs
		146	widely between event loops.
		147
120	To disable the watcher you have to destroy it (e.g. by setting the	148	To disable the watcher you have to destroy it (e.g. by setting the
121	variable you store it in to C<undef> or otherwise deleting all references	149	variable you store it in to C<undef> or otherwise deleting all references
122	to it).	150	to it).
123		151
124	All watchers are created by calling a method on the C<AnyEvent> class.	152	All watchers are created by calling a method on the C<AnyEvent> class.
…		…
126	Many watchers either are used with "recursion" (repeating timers for	154	Many watchers either are used with "recursion" (repeating timers for
127	example), or need to refer to their watcher object in other ways.	155	example), or need to refer to their watcher object in other ways.
128		156
129	An any way to achieve that is this pattern:	157	An any way to achieve that is this pattern:
130		158
131	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	159	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
132	# you can use $w here, for example to undef it	160	# you can use $w here, for example to undef it
133	undef $w;	161	undef $w;
134	});	162	});
135		163
136	Note that C<my $w; $w => combination. This is necessary because in Perl,	164	Note that C<my $w; $w => combination. This is necessary because in Perl,
137	my variables are only visible after the statement in which they are	165	my variables are only visible after the statement in which they are
138	declared.	166	declared.
139		167
140	=head2 I/O WATCHERS	168	=head2 I/O WATCHERS
141		169
142	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	170	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
143	with the following mandatory key-value pairs as arguments:	171	with the following mandatory key-value pairs as arguments:
144		172
145	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	173	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch
		174	for events (AnyEvent might or might not keep a reference to this file
		175	handle). Note that only file handles pointing to things for which
		176	non-blocking operation makes sense are allowed. This includes sockets,
		177	most character devices, pipes, fifos and so on, but not for example files
		178	or block devices.
		179
146	for events. C<poll> must be a string that is either C<r> or C<w>,	180	C<poll> must be a string that is either C<r> or C<w>, which creates a
147	which creates a watcher waiting for "r"eadable or "w"ritable events,	181	watcher waiting for "r"eadable or "w"ritable events, respectively.
		182
148	respectively. C<cb> is the callback to invoke each time the file handle	183	C<cb> is the callback to invoke each time the file handle becomes ready.
149	becomes ready.
150		184
151	Although the callback might get passed parameters, their value and	185	Although the callback might get passed parameters, their value and
152	presence is undefined and you cannot rely on them. Portable AnyEvent	186	presence is undefined and you cannot rely on them. Portable AnyEvent
153	callbacks cannot use arguments passed to I/O watcher callbacks.	187	callbacks cannot use arguments passed to I/O watcher callbacks.
154		188
…		…
158		192
159	Some event loops issue spurious readyness notifications, so you should	193	Some event loops issue spurious readyness notifications, so you should
160	always use non-blocking calls when reading/writing from/to your file	194	always use non-blocking calls when reading/writing from/to your file
161	handles.	195	handles.
162		196
163	Example:
164
165	# wait for readability of STDIN, then read a line and disable the watcher	197	Example: wait for readability of STDIN, then read a line and disable the
		198	watcher.
		199
166	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	200	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
167	chomp (my $input = <STDIN>);	201	chomp (my $input = <STDIN>);
168	warn "read: $input\n";	202	warn "read: $input\n";
169	undef $w;	203	undef $w;
170	});	204	});
…		…
180		214
181	Although the callback might get passed parameters, their value and	215	Although the callback might get passed parameters, their value and
182	presence is undefined and you cannot rely on them. Portable AnyEvent	216	presence is undefined and you cannot rely on them. Portable AnyEvent
183	callbacks cannot use arguments passed to time watcher callbacks.	217	callbacks cannot use arguments passed to time watcher callbacks.
184		218
185	The timer callback will be invoked at most once: if you want a repeating	219	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	220	parameter, C<interval>, as a strictly positive number (> 0), then the
187	and Glib).	221	callback will be invoked regularly at that interval (in fractional
		222	seconds) after the first invocation. If C<interval> is specified with a
		223	false value, then it is treated as if it were missing.
188		224
189	Example:	225	The callback will be rescheduled before invoking the callback, but no
		226	attempt is done to avoid timer drift in most backends, so the interval is
		227	only approximate.
190		228
191	# fire an event after 7.7 seconds	229	Example: fire an event after 7.7 seconds.
		230
192	my $w = AnyEvent->timer (after => 7.7, cb => sub {	231	my $w = AnyEvent->timer (after => 7.7, cb => sub {
193	warn "timeout\n";	232	warn "timeout\n";
194	});	233	});
195		234
196	# to cancel the timer:	235	# to cancel the timer:
197	undef $w;	236	undef $w;
198		237
199	Example 2:
200
201	# fire an event after 0.5 seconds, then roughly every second	238	Example 2: fire an event after 0.5 seconds, then roughly every second.
202	my $w;
203		239
204	my $cb = sub {
205	# cancel the old timer while creating a new one
206	$w = AnyEvent->timer (after => 1, cb => $cb);	240	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		241	warn "timeout\n";
207	};	242	};
208
209	# start the "loop" by creating the first watcher
210	$w = AnyEvent->timer (after => 0.5, cb => $cb);
211		243
212	=head3 TIMING ISSUES	244	=head3 TIMING ISSUES
213		245
214	There are two ways to handle timers: based on real time (relative, "fire	246	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	247	in 10 seconds") and based on wallclock time (absolute, "fire at 12
…		…
227	timers.	259	timers.
228		260
229	AnyEvent always prefers relative timers, if available, matching the	261	AnyEvent always prefers relative timers, if available, matching the
230	AnyEvent API.	262	AnyEvent API.
231		263
		264	AnyEvent has two additional methods that return the "current time":
		265
		266	=over 4
		267
		268	=item AnyEvent->time
		269
		270	This returns the "current wallclock time" as a fractional number of
		271	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
		272	return, and the result is guaranteed to be compatible with those).
		273
		274	It progresses independently of any event loop processing, i.e. each call
		275	will check the system clock, which usually gets updated frequently.
		276
		277	=item AnyEvent->now
		278
		279	This also returns the "current wallclock time", but unlike C<time>, above,
		280	this value might change only once per event loop iteration, depending on
		281	the event loop (most return the same time as C<time>, above). This is the
		282	time that AnyEvent's timers get scheduled against.
		283
		284	I<In almost all cases (in all cases if you don't care), this is the
		285	function to call when you want to know the current time.>
		286
		287	This function is also often faster then C<< AnyEvent->time >>, and
		288	thus the preferred method if you want some timestamp (for example,
		289	L<AnyEvent::Handle> uses this to update it's activity timeouts).
		290
		291	The rest of this section is only of relevance if you try to be very exact
		292	with your timing, you can skip it without bad conscience.
		293
		294	For a practical example of when these times differ, consider L<Event::Lib>
		295	and L<EV> and the following set-up:
		296
		297	The event loop is running and has just invoked one of your callback at
		298	time=500 (assume no other callbacks delay processing). In your callback,
		299	you wait a second by executing C<sleep 1> (blocking the process for a
		300	second) and then (at time=501) you create a relative timer that fires
		301	after three seconds.
		302
		303	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
		304	both return C<501>, because that is the current time, and the timer will
		305	be scheduled to fire at time=504 (C<501> + C<3>).
		306
		307	With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
		308	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
		309	last event processing phase started. With L<EV>, your timer gets scheduled
		310	to run at time=503 (C<500> + C<3>).
		311
		312	In one sense, L<Event::Lib> is more exact, as it uses the current time
		313	regardless of any delays introduced by event processing. However, most
		314	callbacks do not expect large delays in processing, so this causes a
		315	higher drift (and a lot more system calls to get the current time).
		316
		317	In another sense, L<EV> is more exact, as your timer will be scheduled at
		318	the same time, regardless of how long event processing actually took.
		319
		320	In either case, if you care (and in most cases, you don't), then you
		321	can get whatever behaviour you want with any event loop, by taking the
		322	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
		323	account.
		324
		325	=back
		326
232	=head2 SIGNAL WATCHERS	327	=head2 SIGNAL WATCHERS
233		328
234	You can watch for signals using a signal watcher, C<signal> is the signal	329	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	330	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
236	be invoked whenever a signal occurs.	331	callback to be invoked whenever a signal occurs.
237		332
238	Although the callback might get passed parameters, their value and	333	Although the callback might get passed parameters, their value and
239	presence is undefined and you cannot rely on them. Portable AnyEvent	334	presence is undefined and you cannot rely on them. Portable AnyEvent
240	callbacks cannot use arguments passed to signal watcher callbacks.	335	callbacks cannot use arguments passed to signal watcher callbacks.
241		336
242	Multiple signal occurances can be clumped together into one callback	337	Multiple signal occurrences can be clumped together into one callback
243	invocation, and callback invocation will be synchronous. synchronous means	338	invocation, and callback invocation will be synchronous. Synchronous means
244	that it might take a while until the signal gets handled by the process,	339	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.	340	but it is guaranteed not to interrupt any other callbacks.
246		341
247	The main advantage of using these watchers is that you can share a signal	342	The main advantage of using these watchers is that you can share a signal
248	between multiple watchers.	343	between multiple watchers.
249		344
250	This watcher might use C<%SIG>, so programs overwriting those signals	345	This watcher might use C<%SIG>, so programs overwriting those signals
…		…
257	=head2 CHILD PROCESS WATCHERS	352	=head2 CHILD PROCESS WATCHERS
258		353
259	You can also watch on a child process exit and catch its exit status.	354	You can also watch on a child process exit and catch its exit status.
260		355
261	The child process is specified by the C<pid> argument (if set to C<0>, it	356	The child process is specified by the C<pid> argument (if set to C<0>, it
262	watches for any child process exit). The watcher will trigger as often	357	watches for any child process exit). The watcher will triggered only when
263	as status change for the child are received. This works by installing a	358	the child process has finished and an exit status is available, not on
264	signal handler for C<SIGCHLD>. The callback will be called with the pid	359	any trace events (stopped/continued).
265	and exit status (as returned by waitpid), so unlike other watcher types,	360
266	you I<can> rely on child watcher callback arguments.	361	The callback will be called with the pid and exit status (as returned by
		362	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		363	callback arguments.
		364
		365	This watcher type works by installing a signal handler for C<SIGCHLD>,
		366	and since it cannot be shared, nothing else should use SIGCHLD or reap
		367	random child processes (waiting for specific child processes, e.g. inside
		368	C<system>, is just fine).
267		369
268	There is a slight catch to child watchers, however: you usually start them	370	There is a slight catch to child watchers, however: you usually start them
269	I<after> the child process was created, and this means the process could	371	I<after> the child process was created, and this means the process could
270	have exited already (and no SIGCHLD will be sent anymore).	372	have exited already (and no SIGCHLD will be sent anymore).
271		373
…		…
277	AnyEvent program, you I<have> to create at least one watcher before you	379	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>).	380	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
279		381
280	Example: fork a process and wait for it	382	Example: fork a process and wait for it
281		383
282	my $done = AnyEvent->condvar;	384	my $done = AnyEvent->condvar;
283		385
284	AnyEvent::detect; # force event module to be initialised
285
286	my $pid = fork or exit 5;	386	my $pid = fork or exit 5;
287		387
288	my $w = AnyEvent->child (	388	my $w = AnyEvent->child (
289	pid => $pid,	389	pid => $pid,
290	cb => sub {	390	cb => sub {
291	my ($pid, $status) = @_;	391	my ($pid, $status) = @_;
292	warn "pid $pid exited with status $status";	392	warn "pid $pid exited with status $status";
293	$done->send;	393	$done->send;
294	},	394	},
295	);	395	);
296		396
297	# do something else, then wait for process exit	397	# do something else, then wait for process exit
298	$done->wait;	398	$done->recv;
299		399
300	=head2 CONDITION VARIABLES	400	=head2 CONDITION VARIABLES
301		401
302	If you are familiar with some event loops you will know that all of them	402	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	403	require you to run some blocking "loop", "run" or similar function that
…		…
309	The instrument to do that is called a "condition variable", so called	409	The instrument to do that is called a "condition variable", so called
310	because they represent a condition that must become true.	410	because they represent a condition that must become true.
311		411
312	Condition variables can be created by calling the C<< AnyEvent->condvar	412	Condition variables can be created by calling the C<< AnyEvent->condvar
313	>> method, usually without arguments. The only argument pair allowed is	413	>> method, usually without arguments. The only argument pair allowed is
		414
314	C<cb>, which specifies a callback to be called when the condition variable	415	C<cb>, which specifies a callback to be called when the condition variable
315	becomes true.	416	becomes true, with the condition variable as the first argument (but not
		417	the results).
316		418
317	After creation, the conditon variable is "false" until it becomes "true"	419	After creation, the condition variable is "false" until it becomes "true"
318	by calling the C<send> method.	420	by calling the C<send> method (or calling the condition variable as if it
		421	were a callback, read about the caveats in the description for the C<<
		422	->send >> method).
319		423
320	Condition variables are similar to callbacks, except that you can	424	Condition variables are similar to callbacks, except that you can
321	optionally wait for them. They can also be called merge points - points	425	optionally wait for them. They can also be called merge points - points
322	in time where multiple outstandign events have been processed. And yet	426	in time where multiple outstanding events have been processed. And yet
323	another way to call them is transations - each condition variable can be	427	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	428	used to represent a transaction, which finishes at some point and delivers
325	a result.	429	a result.
326		430
327	Condition variables are very useful to signal that something has finished,	431	Condition variables are very useful to signal that something has finished,
328	for example, if you write a module that does asynchronous http requests,	432	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	433	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	434	availability of results. The user can either act when the callback is
331	called or can synchronously C<< ->wait >> for the results.	435	called or can synchronously C<< ->recv >> for the results.
332		436
333	You can also use them to simulate traditional event loops - for example,	437	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	438	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	439	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.	440	button of your app, which would C<< ->send >> the "quit" event.
337		441
338	Note that condition variables recurse into the event loop - if you have	442	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	443	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	444	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,	445	you should avoid making a blocking wait yourself, at least in callbacks,
342	as this asks for trouble.	446	as this asks for trouble.
343		447
344	Condition variables are represented by hash refs in perl, and the keys	448	Condition variables are represented by hash refs in perl, and the keys
…		…
349		453
350	There are two "sides" to a condition variable - the "producer side" which	454	There are two "sides" to a condition variable - the "producer side" which
351	eventually calls C<< -> send >>, and the "consumer side", which waits	455	eventually calls C<< -> send >>, and the "consumer side", which waits
352	for the send to occur.	456	for the send to occur.
353		457
354	Example:	458	Example: wait for a timer.
355		459
356	# wait till the result is ready	460	# wait till the result is ready
357	my $result_ready = AnyEvent->condvar;	461	my $result_ready = AnyEvent->condvar;
358		462
359	# do something such as adding a timer	463	# do something such as adding a timer
…		…
365	cb => sub { $result_ready->send },	469	cb => sub { $result_ready->send },
366	);	470	);
367		471
368	# this "blocks" (while handling events) till the callback	472	# this "blocks" (while handling events) till the callback
369	# calls send	473	# calls send
370	$result_ready->wait;	474	$result_ready->recv;
		475
		476	Example: wait for a timer, but take advantage of the fact that
		477	condition variables are also code references.
		478
		479	my $done = AnyEvent->condvar;
		480	my $delay = AnyEvent->timer (after => 5, cb => $done);
		481	$done->recv;
		482
		483	Example: Imagine an API that returns a condvar and doesn't support
		484	callbacks. This is how you make a synchronous call, for example from
		485	the main program:
		486
		487	use AnyEvent::CouchDB;
		488
		489	...
		490
		491	my @info = $couchdb->info->recv;
		492
		493	And this is how you would just ste a callback to be called whenever the
		494	results are available:
		495
		496	$couchdb->info->cb (sub {
		497	my @info = $_[0]->recv;
		498	});
371		499
372	=head3 METHODS FOR PRODUCERS	500	=head3 METHODS FOR PRODUCERS
373		501
374	These methods should only be used by the producing side, i.e. the	502	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	503	code/module that eventually sends the signal. Note that it is also
…		…
378		506
379	=over 4	507	=over 4
380		508
381	=item $cv->send (...)	509	=item $cv->send (...)
382		510
383	Flag the condition as ready - a running C<< ->wait >> and all further	511	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	512	calls to C<recv> will (eventually) return after this method has been
385	called. If nobody is waiting the send will be remembered.	513	called. If nobody is waiting the send will be remembered.
386		514
387	If a callback has been set on the condition variable, it is called	515	If a callback has been set on the condition variable, it is called
388	immediately from within send.	516	immediately from within send.
389		517
390	Any arguments passed to the C<send> call will be returned by all	518	Any arguments passed to the C<send> call will be returned by all
391	future C<< ->wait >> calls.	519	future C<< ->recv >> calls.
		520
		521	Condition variables are overloaded so one can call them directly
		522	(as a code reference). Calling them directly is the same as calling
		523	C<send>. Note, however, that many C-based event loops do not handle
		524	overloading, so as tempting as it may be, passing a condition variable
		525	instead of a callback does not work. Both the pure perl and EV loops
		526	support overloading, however, as well as all functions that use perl to
		527	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
		528	example).
392		529
393	=item $cv->croak ($error)	530	=item $cv->croak ($error)
394		531
395	Similar to send, but causes all call's wait C<< ->wait >> to invoke	532	Similar to send, but causes all call's to C<< ->recv >> to invoke
396	C<Carp::croak> with the given error message/object/scalar.	533	C<Carp::croak> with the given error message/object/scalar.
397		534
398	This can be used to signal any errors to the condition variable	535	This can be used to signal any errors to the condition variable
399	user/consumer.	536	user/consumer.
400		537
401	=item $cv->begin ([group callback])	538	=item $cv->begin ([group callback])
402		539
403	=item $cv->end	540	=item $cv->end
		541
		542	These two methods are EXPERIMENTAL and MIGHT CHANGE.
404		543
405	These two methods can be used to combine many transactions/events into	544	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	545	one. For example, a function that pings many hosts in parallel might want
407	to use a condition variable for the whole process.	546	to use a condition variable for the whole process.
408		547
…		…
443	doesn't execute once).	582	doesn't execute once).
444		583
445	This is the general pattern when you "fan out" into multiple subrequests:	584	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>	585	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	586	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>.	587	C<begin> and for each subrequest you finish, call C<end>.
449		588
450	=back	589	=back
451		590
452	=head3 METHODS FOR CONSUMERS	591	=head3 METHODS FOR CONSUMERS
453		592
454	These methods should only be used by the consuming side, i.e. the	593	These methods should only be used by the consuming side, i.e. the
455	code awaits the condition.	594	code awaits the condition.
456		595
457	=over 4	596	=over 4
458		597
459	=item $cv->wait	598	=item $cv->recv
460		599
461	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	600	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
462	>> methods have been called on c<$cv>, while servicing other watchers	601	>> methods have been called on c<$cv>, while servicing other watchers
463	normally.	602	normally.
464		603
…		…
475	(programs might want to do that to stay interactive), so I<if you are	614	(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	615	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	616	caller decide whether the call will block or not (for example, by coupling
478	condition variables with some kind of request results and supporting	617	condition variables with some kind of request results and supporting
479	callbacks so the caller knows that getting the result will not block,	618	callbacks so the caller knows that getting the result will not block,
480	while still suppporting blocking waits if the caller so desires).	619	while still supporting blocking waits if the caller so desires).
481		620
482	Another reason I<never> to C<< ->wait >> in a module is that you cannot	621	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	622	sensibly have two C<< ->recv >>'s in parallel, as that would require
484	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	623	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
485	can supply.	624	can supply.
486		625
487	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in	626	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	627	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
489	versions and also integrates coroutines into AnyEvent, making blocking	628	versions and also integrates coroutines into AnyEvent, making blocking
490	C<< ->wait >> calls perfectly safe as long as they are done from another	629	C<< ->recv >> calls perfectly safe as long as they are done from another
491	coroutine (one that doesn't run the event loop).	630	coroutine (one that doesn't run the event loop).
492		631
493	You can ensure that C<< -wait >> never blocks by setting a callback and	632	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	633	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	634	time). This will work even when the event loop does not support blocking
496	waits otherwise.	635	waits otherwise.
497		636
498	=item $bool = $cv->ready	637	=item $bool = $cv->ready
499		638
500	Returns true when the condition is "true", i.e. whether C<send> or	639	Returns true when the condition is "true", i.e. whether C<send> or
501	C<croak> have been called.	640	C<croak> have been called.
502		641
503	=item $cb = $cv->cb ([new callback])	642	=item $cb = $cv->cb ($cb->($cv))
504		643
505	This is a mutator function that returns the callback set and optionally	644	This is a mutator function that returns the callback set and optionally
506	replaces it before doing so.	645	replaces it before doing so.
507		646
508	The callback will be called when the condition becomes "true", i.e. when	647	The callback will be called when the condition becomes "true", i.e. when
509	C<send> or C<croak> are called. Calling C<wait> inside the callback	648	C<send> or C<croak> are called, with the only argument being the condition
510	or at any later time is guaranteed not to block.	649	variable itself. Calling C<recv> inside the callback or at any later time
		650	is guaranteed not to block.
511		651
512	=back	652	=back
513		653
514	=head1 GLOBAL VARIABLES AND FUNCTIONS	654	=head1 GLOBAL VARIABLES AND FUNCTIONS
515		655
…		…
549	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	689	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
550	if necessary. You should only call this function right before you would	690	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	691	have created an AnyEvent watcher anyway, that is, as late as possible at
552	runtime.	692	runtime.
553		693
554	=item AnyEvent::on_detect { BLOCK }	694	=item $guard = AnyEvent::post_detect { BLOCK }
555		695
556	Arranges for the code block to be executed as soon as the event model is	696	Arranges for the code block to be executed as soon as the event model is
557	autodetected (or immediately if this has already happened).	697	autodetected (or immediately if this has already happened).
558		698
		699	If called in scalar or list context, then it creates and returns an object
		700	that automatically removes the callback again when it is destroyed. See
		701	L<Coro::BDB> for a case where this is useful.
		702
559	=item @AnyEvent::on_detect	703	=item @AnyEvent::post_detect
560		704
561	If there are any code references in this array (you can C<push> to it	705	If there are any code references in this array (you can C<push> to it
562	before or after loading AnyEvent), then they will called directly after	706	before or after loading AnyEvent), then they will called directly after
563	the event loop has been chosen.	707	the event loop has been chosen.
564		708
565	You should check C<$AnyEvent::MODEL> before adding to this array, though:	709	You should check C<$AnyEvent::MODEL> before adding to this array, though:
566	if it contains a true value then the event loop has already been detected,	710	if it contains a true value then the event loop has already been detected,
567	and the array will be ignored.	711	and the array will be ignored.
568		712
569	Best use C<AnyEvent::on_detect { BLOCK }> instead.	713	Best use C<AnyEvent::post_detect { BLOCK }> instead.
570		714
571	=back	715	=back
572		716
573	=head1 WHAT TO DO IN A MODULE	717	=head1 WHAT TO DO IN A MODULE
574		718
…		…
578	Be careful when you create watchers in the module body - AnyEvent will	722	Be careful when you create watchers in the module body - AnyEvent will
579	decide which event module to use as soon as the first method is called, so	723	decide which event module to use as soon as the first method is called, so
580	by calling AnyEvent in your module body you force the user of your module	724	by calling AnyEvent in your module body you force the user of your module
581	to load the event module first.	725	to load the event module first.
582		726
583	Never call C<< ->wait >> on a condition variable unless you I<know> that	727	Never call C<< ->recv >> on a condition variable unless you I<know> that
584	the C<< ->send >> method has been called on it already. This is	728	the C<< ->send >> method has been called on it already. This is
585	because it will stall the whole program, and the whole point of using	729	because it will stall the whole program, and the whole point of using
586	events is to stay interactive.	730	events is to stay interactive.
587		731
588	It is fine, however, to call C<< ->wait >> when the user of your module	732	It is fine, however, to call C<< ->recv >> when the user of your module
589	requests it (i.e. if you create a http request object ad have a method	733	requests it (i.e. if you create a http request object ad have a method
590	called C<results> that returns the results, it should call C<< ->wait >>	734	called C<results> that returns the results, it should call C<< ->recv >>
591	freely, as the user of your module knows what she is doing. always).	735	freely, as the user of your module knows what she is doing. always).
592		736
593	=head1 WHAT TO DO IN THE MAIN PROGRAM	737	=head1 WHAT TO DO IN THE MAIN PROGRAM
594		738
595	There will always be a single main program - the only place that should	739	There will always be a single main program - the only place that should
…		…
597		741
598	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	742	If it doesn't care, it can just "use AnyEvent" and use it itself, or not
599	do anything special (it does not need to be event-based) and let AnyEvent	743	do anything special (it does not need to be event-based) and let AnyEvent
600	decide which implementation to chose if some module relies on it.	744	decide which implementation to chose if some module relies on it.
601		745
602	If the main program relies on a specific event model. For example, in	746	If the main program relies on a specific event model - for example, in
603	Gtk2 programs you have to rely on the Glib module. You should load the	747	Gtk2 programs you have to rely on the Glib module - you should load the
604	event module before loading AnyEvent or any module that uses it: generally	748	event module before loading AnyEvent or any module that uses it: generally
605	speaking, you should load it as early as possible. The reason is that	749	speaking, you should load it as early as possible. The reason is that
606	modules might create watchers when they are loaded, and AnyEvent will	750	modules might create watchers when they are loaded, and AnyEvent will
607	decide on the event model to use as soon as it creates watchers, and it	751	decide on the event model to use as soon as it creates watchers, and it
608	might chose the wrong one unless you load the correct one yourself.	752	might chose the wrong one unless you load the correct one yourself.
609		753
610	You can chose to use a rather inefficient pure-perl implementation by	754	You can chose to use a pure-perl implementation by loading the
611	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	755	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
612	behaviour everywhere, but letting AnyEvent chose is generally better.	756	everywhere, but letting AnyEvent chose the model is generally better.
		757
		758	=head2 MAINLOOP EMULATION
		759
		760	Sometimes (often for short test scripts, or even standalone programs who
		761	only want to use AnyEvent), you do not want to run a specific event loop.
		762
		763	In that case, you can use a condition variable like this:
		764
		765	AnyEvent->condvar->recv;
		766
		767	This has the effect of entering the event loop and looping forever.
		768
		769	Note that usually your program has some exit condition, in which case
		770	it is better to use the "traditional" approach of storing a condition
		771	variable somewhere, waiting for it, and sending it when the program should
		772	exit cleanly.
		773
613		774
614	=head1 OTHER MODULES	775	=head1 OTHER MODULES
615		776
616	The following is a non-exhaustive list of additional modules that use	777	The following is a non-exhaustive list of additional modules that use
617	AnyEvent and can therefore be mixed easily with other AnyEvent modules	778	AnyEvent and can therefore be mixed easily with other AnyEvent modules
…		…
623	=item L<AnyEvent::Util>	784	=item L<AnyEvent::Util>
624		785
625	Contains various utility functions that replace often-used but blocking	786	Contains various utility functions that replace often-used but blocking
626	functions such as C<inet_aton> by event-/callback-based versions.	787	functions such as C<inet_aton> by event-/callback-based versions.
627		788
		789	=item L<AnyEvent::Socket>
		790
		791	Provides various utility functions for (internet protocol) sockets,
		792	addresses and name resolution. Also functions to create non-blocking tcp
		793	connections or tcp servers, with IPv6 and SRV record support and more.
		794
628	=item L<AnyEvent::Handle>	795	=item L<AnyEvent::Handle>
629		796
630	Provide read and write buffers and manages watchers for reads and writes.	797	Provide read and write buffers, manages watchers for reads and writes,
		798	supports raw and formatted I/O, I/O queued and fully transparent and
		799	non-blocking SSL/TLS.
631		800
632	=item L<AnyEvent::Socket>	801	=item L<AnyEvent::DNS>
633		802
634	Provides a means to do non-blocking connects, accepts etc.	803	Provides rich asynchronous DNS resolver capabilities.
		804
		805	=item L<AnyEvent::HTTP>
		806
		807	A simple-to-use HTTP library that is capable of making a lot of concurrent
		808	HTTP requests.
635		809
636	=item L<AnyEvent::HTTPD>	810	=item L<AnyEvent::HTTPD>
637		811
638	Provides a simple web application server framework.	812	Provides a simple web application server framework.
639		813
640	=item L<AnyEvent::DNS>
641
642	Provides asynchronous DNS resolver capabilities, beyond what
643	L<AnyEvent::Util> offers.
644
645	=item L<AnyEvent::FastPing>	814	=item L<AnyEvent::FastPing>
646		815
647	The fastest ping in the west.	816	The fastest ping in the west.
648		817
		818	=item L<AnyEvent::DBI>
		819
		820	Executes L<DBI> requests asynchronously in a proxy process.
		821
		822	=item L<AnyEvent::AIO>
		823
		824	Truly asynchronous I/O, should be in the toolbox of every event
		825	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		826	together.
		827
		828	=item L<AnyEvent::BDB>
		829
		830	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		831	L<BDB> and AnyEvent together.
		832
		833	=item L<AnyEvent::GPSD>
		834
		835	A non-blocking interface to gpsd, a daemon delivering GPS information.
		836
		837	=item L<AnyEvent::IGS>
		838
		839	A non-blocking interface to the Internet Go Server protocol (used by
		840	L<App::IGS>).
		841
649	=item L<Net::IRC3>	842	=item L<AnyEvent::IRC>
650		843
651	AnyEvent based IRC client module family.	844	AnyEvent based IRC client module family (replacing the older Net::IRC3).
652		845
653	=item L<Net::XMPP2>	846	=item L<Net::XMPP2>
654		847
655	AnyEvent based XMPP (Jabber protocol) module family.	848	AnyEvent based XMPP (Jabber protocol) module family.
656		849
…		…
669		862
670	=item L<IO::Lambda>	863	=item L<IO::Lambda>
671		864
672	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	865	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
673		866
674	=item L<IO::AIO>
675
676	Truly asynchronous I/O, should be in the toolbox of every event
677	programmer. Can be trivially made to use AnyEvent.
678
679	=item L<BDB>
680
681	Truly asynchronous Berkeley DB access. Can be trivially made to use
682	AnyEvent.
683
684	=back	867	=back
685		868
686	=cut	869	=cut
687		870
688	package AnyEvent;	871	package AnyEvent;
689		872
690	no warnings;	873	no warnings;
691	use strict;	874	use strict qw(vars subs);
692		875
693	use Carp;	876	use Carp;
694		877
695	our $VERSION = '3.4';	878	our $VERSION = 4.35;
696	our $MODEL;	879	our $MODEL;
697		880
698	our $AUTOLOAD;	881	our $AUTOLOAD;
699	our @ISA;	882	our @ISA;
700		883
		884	our @REGISTRY;
		885
		886	our $WIN32;
		887
		888	BEGIN {
		889	my $win32 = ! ! ($^O =~ /mswin32/i);
		890	eval "sub WIN32(){ $win32 }";
		891	}
		892
701	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	893	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
702		894
703	our @REGISTRY;	895	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
		896
		897	{
		898	my $idx;
		899	$PROTOCOL{$_} = ++$idx
		900	for reverse split /\s*,\s*/,
		901	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
		902	}
704		903
705	my @models = (	904	my @models = (
706	[EV:: => AnyEvent::Impl::EV::],	905	[EV:: => AnyEvent::Impl::EV::],
707	[Event:: => AnyEvent::Impl::Event::],	906	[Event:: => AnyEvent::Impl::Event::],
708	[Tk:: => AnyEvent::Impl::Tk::],
709	[Wx:: => AnyEvent::Impl::POE::],
710	[Prima:: => AnyEvent::Impl::POE::],
711	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	907	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
712	# everything below here will not be autoprobed as the pureperl backend should work everywhere	908	# everything below here will not be autoprobed
713	[Glib:: => AnyEvent::Impl::Glib::],	909	# as the pureperl backend should work everywhere
		910	# and is usually faster
		911	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		912	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
714	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	913	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
715	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	914	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
716	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	915	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
		916	[Wx:: => AnyEvent::Impl::POE::],
		917	[Prima:: => AnyEvent::Impl::POE::],
717	);	918	);
718		919
719	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);	920	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
720		921
721	our @on_detect;	922	our @post_detect;
722		923
723	sub on_detect(&) {	924	sub post_detect(&) {
		925	my ($cb) = @_;
		926
724	if ($MODEL) {	927	if ($MODEL) {
725	$_[0]->();	928	$cb->();
		929
		930	1
726	} else {	931	} else {
727	push @on_detect, $_[0];	932	push @post_detect, $cb;
		933
		934	defined wantarray
		935	? bless \$cb, "AnyEvent::Util::PostDetect"
		936	: ()
728	}	937	}
		938	}
		939
		940	sub AnyEvent::Util::PostDetect::DESTROY {
		941	@post_detect = grep $_ != ${$_[0]}, @post_detect;
729	}	942	}
730		943
731	sub detect() {	944	sub detect() {
732	unless ($MODEL) {	945	unless ($MODEL) {
733	no strict 'refs';	946	no strict 'refs';
		947	local $SIG{__DIE__};
734		948
735	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	949	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
736	my $model = "AnyEvent::Impl::$1";	950	my $model = "AnyEvent::Impl::$1";
737	if (eval "require $model") {	951	if (eval "require $model") {
738	$MODEL = $model;	952	$MODEL = $model;
…		…
772	$MODEL	986	$MODEL
773	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	987	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
774	}	988	}
775	}	989	}
776		990
		991	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		992
777	unshift @ISA, $MODEL;	993	unshift @ISA, $MODEL;
778	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
779		994
		995	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		996
780	(shift @on_detect)->() while @on_detect;	997	(shift @post_detect)->() while @post_detect;
781	}	998	}
782		999
783	$MODEL	1000	$MODEL
784	}	1001	}
785		1002
…		…
793		1010
794	my $class = shift;	1011	my $class = shift;
795	$class->$func (@_);	1012	$class->$func (@_);
796	}	1013	}
797		1014
		1015	# utility function to dup a filehandle. this is used by many backends
		1016	# to support binding more than one watcher per filehandle (they usually
		1017	# allow only one watcher per fd, so we dup it to get a different one).
		1018	sub _dupfh($$$$) {
		1019	my ($poll, $fh, $r, $w) = @_;
		1020
		1021	# cygwin requires the fh mode to be matching, unix doesn't
		1022	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		1023	: $poll eq "w" ? ($w, ">")
		1024	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		1025
		1026	open my $fh2, "$mode&" . fileno $fh
		1027	or die "cannot dup() filehandle: $!";
		1028
		1029	# we assume CLOEXEC is already set by perl in all important cases
		1030
		1031	($fh2, $rw)
		1032	}
		1033
798	package AnyEvent::Base;	1034	package AnyEvent::Base;
799		1035
		1036	# default implementation for now and time
		1037
		1038	BEGIN {
		1039	if (eval "use Time::HiRes (); time (); 1") {
		1040	*_time = \&Time::HiRes::time;
		1041	# if (eval "use POSIX (); (POSIX::times())...
		1042	} else {
		1043	*_time = sub { time }; # epic fail
		1044	}
		1045	}
		1046
		1047	sub time { _time }
		1048	sub now { _time }
		1049
800	# default implementation for ->condvar, ->wait, ->broadcast	1050	# default implementation for ->condvar
801		1051
802	sub condvar {	1052	sub condvar {
803	bless \my $flag, "AnyEvent::Base::CondVar"	1053	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
804	}
805
806	sub AnyEvent::Base::CondVar::broadcast {
807	${$_[0]}++;
808	}
809
810	sub AnyEvent::Base::CondVar::wait {
811	AnyEvent->one_event while !${$_[0]};
812	}	1054	}
813		1055
814	# default implementation for ->signal	1056	# default implementation for ->signal
815		1057
816	our %SIG_CB;	1058	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1059
		1060	sub _signal_exec {
		1061	sysread $SIGPIPE_R, my $dummy, 4;
		1062
		1063	while (%SIG_EV) {
		1064	for (keys %SIG_EV) {
		1065	delete $SIG_EV{$_};
		1066	$_->() for values %{ $SIG_CB{$_} || {} };
		1067	}
		1068	}
		1069	}
817		1070
818	sub signal {	1071	sub signal {
819	my (undef, %arg) = @_;	1072	my (undef, %arg) = @_;
820		1073
		1074	unless ($SIGPIPE_R) {
		1075	if (AnyEvent::WIN32) {
		1076	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1077	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1078	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1079	} else {
		1080	pipe $SIGPIPE_R, $SIGPIPE_W;
		1081	require Fcntl;
		1082	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1083	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1084	}
		1085
		1086	$SIGPIPE_R
		1087	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1088
		1089	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1090	}
		1091
821	my $signal = uc $arg{signal}	1092	my $signal = uc $arg{signal}
822	or Carp::croak "required option 'signal' is missing";	1093	or Carp::croak "required option 'signal' is missing";
823		1094
824	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1095	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
825	$SIG{$signal} ||= sub {	1096	$SIG{$signal} ||= sub {
826	$_->() for values %{ $SIG_CB{$signal} || {} };	1097	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1098	undef $SIG_EV{$signal};
827	};	1099	};
828		1100
829	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1101	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
830	}	1102	}
831		1103
832	sub AnyEvent::Base::Signal::DESTROY {	1104	sub AnyEvent::Base::Signal::DESTROY {
833	my ($signal, $cb) = @{$_[0]};	1105	my ($signal, $cb) = @{$_[0]};
834		1106
835	delete $SIG_CB{$signal}{$cb};	1107	delete $SIG_CB{$signal}{$cb};
836		1108
837	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1109	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
838	}	1110	}
839		1111
840	# default implementation for ->child	1112	# default implementation for ->child
841		1113
842	our %PID_CB;	1114	our %PID_CB;
…		…
869	or Carp::croak "required option 'pid' is missing";	1141	or Carp::croak "required option 'pid' is missing";
870		1142
871	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1143	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
872		1144
873	unless ($WNOHANG) {	1145	unless ($WNOHANG) {
874	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1;	1146	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
875	}	1147	}
876		1148
877	unless ($CHLD_W) {	1149	unless ($CHLD_W) {
878	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1150	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
879	# child could be a zombie already, so make at least one round	1151	# child could be a zombie already, so make at least one round
…		…
889	delete $PID_CB{$pid}{$cb};	1161	delete $PID_CB{$pid}{$cb};
890	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1162	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
891		1163
892	undef $CHLD_W unless keys %PID_CB;	1164	undef $CHLD_W unless keys %PID_CB;
893	}	1165	}
		1166
		1167	package AnyEvent::CondVar;
		1168
		1169	our @ISA = AnyEvent::CondVar::Base::;
		1170
		1171	package AnyEvent::CondVar::Base;
		1172
		1173	use overload
		1174	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		1175	fallback => 1;
		1176
		1177	sub _send {
		1178	# nop
		1179	}
		1180
		1181	sub send {
		1182	my $cv = shift;
		1183	$cv->{_ae_sent} = [@_];
		1184	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		1185	$cv->_send;
		1186	}
		1187
		1188	sub croak {
		1189	$_[0]{_ae_croak} = $_[1];
		1190	$_[0]->send;
		1191	}
		1192
		1193	sub ready {
		1194	$_[0]{_ae_sent}
		1195	}
		1196
		1197	sub _wait {
		1198	AnyEvent->one_event while !$_[0]{_ae_sent};
		1199	}
		1200
		1201	sub recv {
		1202	$_[0]->_wait;
		1203
		1204	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		1205	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		1206	}
		1207
		1208	sub cb {
		1209	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		1210	$_[0]{_ae_cb}
		1211	}
		1212
		1213	sub begin {
		1214	++$_[0]{_ae_counter};
		1215	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		1216	}
		1217
		1218	sub end {
		1219	return if --$_[0]{_ae_counter};
		1220	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
		1221	}
		1222
		1223	# undocumented/compatibility with pre-3.4
		1224	*broadcast = \&send;
		1225	*wait = \&_wait;
		1226
		1227	=head1 ERROR AND EXCEPTION HANDLING
		1228
		1229	In general, AnyEvent does not do any error handling - it relies on the
		1230	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1231	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1232	checking of all AnyEvent methods, however, which is highly useful during
		1233	development.
		1234
		1235	As for exception handling (i.e. runtime errors and exceptions thrown while
		1236	executing a callback), this is not only highly event-loop specific, but
		1237	also not in any way wrapped by this module, as this is the job of the main
		1238	program.
		1239
		1240	The pure perl event loop simply re-throws the exception (usually
		1241	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1242	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1243	so on.
		1244
		1245	=head1 ENVIRONMENT VARIABLES
		1246
		1247	The following environment variables are used by this module or its
		1248	submodules:
		1249
		1250	=over 4
		1251
		1252	=item C<PERL_ANYEVENT_VERBOSE>
		1253
		1254	By default, AnyEvent will be completely silent except in fatal
		1255	conditions. You can set this environment variable to make AnyEvent more
		1256	talkative.
		1257
		1258	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1259	conditions, such as not being able to load the event model specified by
		1260	C<PERL_ANYEVENT_MODEL>.
		1261
		1262	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1263	model it chooses.
		1264
		1265	=item C<PERL_ANYEVENT_STRICT>
		1266
		1267	AnyEvent does not do much argument checking by default, as thorough
		1268	argument checking is very costly. Setting this variable to a true value
		1269	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1270	check the arguments passed to most method calls. If it finds any problems
		1271	it will croak.
		1272
		1273	In other words, enables "strict" mode.
		1274
		1275	Unlike C<use strict>, it is definitely recommended ot keep it off in
		1276	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1277	developing programs can be very useful, however.
		1278
		1279	=item C<PERL_ANYEVENT_MODEL>
		1280
		1281	This can be used to specify the event model to be used by AnyEvent, before
		1282	auto detection and -probing kicks in. It must be a string consisting
		1283	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1284	and the resulting module name is loaded and if the load was successful,
		1285	used as event model. If it fails to load AnyEvent will proceed with
		1286	auto detection and -probing.
		1287
		1288	This functionality might change in future versions.
		1289
		1290	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1291	could start your program like this:
		1292
		1293	PERL_ANYEVENT_MODEL=Perl perl ...
		1294
		1295	=item C<PERL_ANYEVENT_PROTOCOLS>
		1296
		1297	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1298	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1299	of auto probing).
		1300
		1301	Must be set to a comma-separated list of protocols or address families,
		1302	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1303	used, and preference will be given to protocols mentioned earlier in the
		1304	list.
		1305
		1306	This variable can effectively be used for denial-of-service attacks
		1307	against local programs (e.g. when setuid), although the impact is likely
		1308	small, as the program has to handle conenction and other failures anyways.
		1309
		1310	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1311	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1312	- only support IPv4, never try to resolve or contact IPv6
		1313	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1314	IPv6, but prefer IPv6 over IPv4.
		1315
		1316	=item C<PERL_ANYEVENT_EDNS0>
		1317
		1318	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1319	for DNS. This extension is generally useful to reduce DNS traffic, but
		1320	some (broken) firewalls drop such DNS packets, which is why it is off by
		1321	default.
		1322
		1323	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1324	EDNS0 in its DNS requests.
		1325
		1326	=item C<PERL_ANYEVENT_MAX_FORKS>
		1327
		1328	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1329	will create in parallel.
		1330
		1331	=back
894		1332
895	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1333	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
896		1334
897	This is an advanced topic that you do not normally need to use AnyEvent in	1335	This is an advanced topic that you do not normally need to use AnyEvent in
898	a module. This section is only of use to event loop authors who want to	1336	a module. This section is only of use to event loop authors who want to
…		…
932		1370
933	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1371	I<rxvt-unicode> also cheats a bit by not providing blocking access to
934	condition variables: code blocking while waiting for a condition will	1372	condition variables: code blocking while waiting for a condition will
935	C<die>. This still works with most modules/usages, and blocking calls must	1373	C<die>. This still works with most modules/usages, and blocking calls must
936	not be done in an interactive application, so it makes sense.	1374	not be done in an interactive application, so it makes sense.
937
938	=head1 ENVIRONMENT VARIABLES
939
940	The following environment variables are used by this module:
941
942	=over 4
943
944	=item C<PERL_ANYEVENT_VERBOSE>
945
946	By default, AnyEvent will be completely silent except in fatal
947	conditions. You can set this environment variable to make AnyEvent more
948	talkative.
949
950	When set to C<1> or higher, causes AnyEvent to warn about unexpected
951	conditions, such as not being able to load the event model specified by
952	C<PERL_ANYEVENT_MODEL>.
953
954	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
955	model it chooses.
956
957	=item C<PERL_ANYEVENT_MODEL>
958
959	This can be used to specify the event model to be used by AnyEvent, before
960	autodetection and -probing kicks in. It must be a string consisting
961	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
962	and the resulting module name is loaded and if the load was successful,
963	used as event model. If it fails to load AnyEvent will proceed with
964	autodetection and -probing.
965
966	This functionality might change in future versions.
967
968	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
969	could start your program like this:
970
971	PERL_ANYEVENT_MODEL=Perl perl ...
972
973	=back
974		1375
975	=head1 EXAMPLE PROGRAM	1376	=head1 EXAMPLE PROGRAM
976		1377
977	The following program uses an I/O watcher to read data from STDIN, a timer	1378	The following program uses an I/O watcher to read data from STDIN, a timer
978	to display a message once per second, and a condition variable to quit the	1379	to display a message once per second, and a condition variable to quit the
…		…
987	poll => 'r',	1388	poll => 'r',
988	cb => sub {	1389	cb => sub {
989	warn "io event <$_[0]>\n"; # will always output <r>	1390	warn "io event <$_[0]>\n"; # will always output <r>
990	chomp (my $input = <STDIN>); # read a line	1391	chomp (my $input = <STDIN>); # read a line
991	warn "read: $input\n"; # output what has been read	1392	warn "read: $input\n"; # output what has been read
992	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1393	$cv->send if $input =~ /^q/i; # quit program if /^q/i
993	},	1394	},
994	);	1395	);
995		1396
996	my $time_watcher; # can only be used once	1397	my $time_watcher; # can only be used once
997		1398
…		…
1002	});	1403	});
1003	}	1404	}
1004		1405
1005	new_timer; # create first timer	1406	new_timer; # create first timer
1006		1407
1007	$cv->wait; # wait until user enters /^q/i	1408	$cv->recv; # wait until user enters /^q/i
1008		1409
1009	=head1 REAL-WORLD EXAMPLE	1410	=head1 REAL-WORLD EXAMPLE
1010		1411
1011	Consider the L<Net::FCP> module. It features (among others) the following	1412	Consider the L<Net::FCP> module. It features (among others) the following
1012	API calls, which are to freenet what HTTP GET requests are to http:	1413	API calls, which are to freenet what HTTP GET requests are to http:
…		…
1062	syswrite $txn->{fh}, $txn->{request}	1463	syswrite $txn->{fh}, $txn->{request}
1063	or die "connection or write error";	1464	or die "connection or write error";
1064	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1465	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1065		1466
1066	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1467	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
1067	result and signals any possible waiters that the request ahs finished:	1468	result and signals any possible waiters that the request has finished:
1068		1469
1069	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1470	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1070		1471
1071	if (end-of-file or data complete) {	1472	if (end-of-file or data complete) {
1072	$txn->{result} = $txn->{buf};	1473	$txn->{result} = $txn->{buf};
1073	$txn->{finished}->broadcast;	1474	$txn->{finished}->send;
1074	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1475	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
1075	}	1476	}
1076		1477
1077	The C<result> method, finally, just waits for the finished signal (if the	1478	The C<result> method, finally, just waits for the finished signal (if the
1078	request was already finished, it doesn't wait, of course, and returns the	1479	request was already finished, it doesn't wait, of course, and returns the
1079	data:	1480	data:
1080		1481
1081	$txn->{finished}->wait;	1482	$txn->{finished}->recv;
1082	return $txn->{result};	1483	return $txn->{result};
1083		1484
1084	The actual code goes further and collects all errors (C<die>s, exceptions)	1485	The actual code goes further and collects all errors (C<die>s, exceptions)
1085	that occured during request processing. The C<result> method detects	1486	that occurred during request processing. The C<result> method detects
1086	whether an exception as thrown (it is stored inside the $txn object)	1487	whether an exception as thrown (it is stored inside the $txn object)
1087	and just throws the exception, which means connection errors and other	1488	and just throws the exception, which means connection errors and other
1088	problems get reported tot he code that tries to use the result, not in a	1489	problems get reported tot he code that tries to use the result, not in a
1089	random callback.	1490	random callback.
1090		1491
…		…
1121		1522
1122	my $quit = AnyEvent->condvar;	1523	my $quit = AnyEvent->condvar;
1123		1524
1124	$fcp->txn_client_get ($url)->cb (sub {	1525	$fcp->txn_client_get ($url)->cb (sub {
1125	...	1526	...
1126	$quit->broadcast;	1527	$quit->send;
1127	});	1528	});
1128		1529
1129	$quit->wait;	1530	$quit->recv;
1130		1531
1131		1532
1132	=head1 BENCHMARKS	1533	=head1 BENCHMARKS
1133		1534
1134	To give you an idea of the performance and overheads that AnyEvent adds	1535	To give you an idea of the performance and overheads that AnyEvent adds
…		…
1136	of various event loops I prepared some benchmarks.	1537	of various event loops I prepared some benchmarks.
1137		1538
1138	=head2 BENCHMARKING ANYEVENT OVERHEAD	1539	=head2 BENCHMARKING ANYEVENT OVERHEAD
1139		1540
1140	Here is a benchmark of various supported event models used natively and	1541	Here is a benchmark of various supported event models used natively and
1141	through anyevent. The benchmark creates a lot of timers (with a zero	1542	through AnyEvent. The benchmark creates a lot of timers (with a zero
1142	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	1543	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1143	which it is), lets them fire exactly once and destroys them again.	1544	which it is), lets them fire exactly once and destroys them again.
1144		1545
1145	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1546	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1146	distribution.	1547	distribution.
…		…
1163	all watchers, to avoid adding memory overhead. That means closure creation	1564	all watchers, to avoid adding memory overhead. That means closure creation
1164	and memory usage is not included in the figures.	1565	and memory usage is not included in the figures.
1165		1566
1166	I<invoke> is the time, in microseconds, used to invoke a simple	1567	I<invoke> is the time, in microseconds, used to invoke a simple
1167	callback. The callback simply counts down a Perl variable and after it was	1568	callback. The callback simply counts down a Perl variable and after it was
1168	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1569	invoked "watcher" times, it would C<< ->send >> a condvar once to
1169	signal the end of this phase.	1570	signal the end of this phase.
1170		1571
1171	I<destroy> is the time, in microseconds, that it takes to destroy a single	1572	I<destroy> is the time, in microseconds, that it takes to destroy a single
1172	watcher.	1573	watcher.
1173		1574
1174	=head3 Results	1575	=head3 Results
1175		1576
1176	name watchers bytes create invoke destroy comment	1577	name watchers bytes create invoke destroy comment
1177	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1578	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1178	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1579	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1179	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1580	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1180	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1581	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1181	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1582	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1182	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	1583	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1183	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1584	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1184	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1585	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1185	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1586	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1186	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1587	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1187		1588
1188	=head3 Discussion	1589	=head3 Discussion
1189		1590
1190	The benchmark does I<not> measure scalability of the event loop very	1591	The benchmark does I<not> measure scalability of the event loop very
1191	well. For example, a select-based event loop (such as the pure perl one)	1592	well. For example, a select-based event loop (such as the pure perl one)
…		…
1269		1670
1270	=back	1671	=back
1271		1672
1272	=head2 BENCHMARKING THE LARGE SERVER CASE	1673	=head2 BENCHMARKING THE LARGE SERVER CASE
1273		1674
1274	This benchmark atcually benchmarks the event loop itself. It works by	1675	This benchmark actually benchmarks the event loop itself. It works by
1275	creating a number of "servers": each server consists of a socketpair, a	1676	creating a number of "servers": each server consists of a socket pair, a
1276	timeout watcher that gets reset on activity (but never fires), and an I/O	1677	timeout watcher that gets reset on activity (but never fires), and an I/O
1277	watcher waiting for input on one side of the socket. Each time the socket	1678	watcher waiting for input on one side of the socket. Each time the socket
1278	watcher reads a byte it will write that byte to a random other "server".	1679	watcher reads a byte it will write that byte to a random other "server".
1279		1680
1280	The effect is that there will be a lot of I/O watchers, only part of which	1681	The effect is that there will be a lot of I/O watchers, only part of which
1281	are active at any one point (so there is a constant number of active	1682	are active at any one point (so there is a constant number of active
1282	fds for each loop iterstaion, but which fds these are is random). The	1683	fds for each loop iteration, but which fds these are is random). The
1283	timeout is reset each time something is read because that reflects how	1684	timeout is reset each time something is read because that reflects how
1284	most timeouts work (and puts extra pressure on the event loops).	1685	most timeouts work (and puts extra pressure on the event loops).
1285		1686
1286	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1687	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1287	(1%) are active. This mirrors the activity of large servers with many	1688	(1%) are active. This mirrors the activity of large servers with many
1288	connections, most of which are idle at any one point in time.	1689	connections, most of which are idle at any one point in time.
1289		1690
1290	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1691	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1291	distribution.	1692	distribution.
…		…
1293	=head3 Explanation of the columns	1694	=head3 Explanation of the columns
1294		1695
1295	I<sockets> is the number of sockets, and twice the number of "servers" (as	1696	I<sockets> is the number of sockets, and twice the number of "servers" (as
1296	each server has a read and write socket end).	1697	each server has a read and write socket end).
1297		1698
1298	I<create> is the time it takes to create a socketpair (which is	1699	I<create> is the time it takes to create a socket pair (which is
1299	nontrivial) and two watchers: an I/O watcher and a timeout watcher.	1700	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1300		1701
1301	I<request>, the most important value, is the time it takes to handle a	1702	I<request>, the most important value, is the time it takes to handle a
1302	single "request", that is, reading the token from the pipe and forwarding	1703	single "request", that is, reading the token from the pipe and forwarding
1303	it to another server. This includes deleting the old timeout and creating	1704	it to another server. This includes deleting the old timeout and creating
…		…
1376	speed most when you have lots of watchers, not when you only have a few of	1777	speed most when you have lots of watchers, not when you only have a few of
1377	them).	1778	them).
1378		1779
1379	EV is again fastest.	1780	EV is again fastest.
1380		1781
1381	Perl again comes second. It is noticably faster than the C-based event	1782	Perl again comes second. It is noticeably faster than the C-based event
1382	loops Event and Glib, although the difference is too small to really	1783	loops Event and Glib, although the difference is too small to really
1383	matter.	1784	matter.
1384		1785
1385	POE also performs much better in this case, but is is still far behind the	1786	POE also performs much better in this case, but is is still far behind the
1386	others.	1787	others.
…		…
1391		1792
1392	=item * C-based event loops perform very well with small number of	1793	=item * C-based event loops perform very well with small number of
1393	watchers, as the management overhead dominates.	1794	watchers, as the management overhead dominates.
1394		1795
1395	=back	1796	=back
		1797
		1798
		1799	=head1 SIGNALS
		1800
		1801	AnyEvent currently installs handlers for these signals:
		1802
		1803	=over 4
		1804
		1805	=item SIGCHLD
		1806
		1807	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		1808	emulation for event loops that do not support them natively. Also, some
		1809	event loops install a similar handler.
		1810
		1811	=item SIGPIPE
		1812
		1813	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		1814	when AnyEvent gets loaded.
		1815
		1816	The rationale for this is that AnyEvent users usually do not really depend
		1817	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		1818	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		1819	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		1820	some random socket.
		1821
		1822	The rationale for installing a no-op handler as opposed to ignoring it is
		1823	that this way, the handler will be restored to defaults on exec.
		1824
		1825	Feel free to install your own handler, or reset it to defaults.
		1826
		1827	=back
		1828
		1829	=cut
		1830
		1831	$SIG{PIPE} = sub { }
		1832	unless defined $SIG{PIPE};
1396		1833
1397		1834
1398	=head1 FORK	1835	=head1 FORK
1399		1836
1400	Most event libraries are not fork-safe. The ones who are usually are	1837	Most event libraries are not fork-safe. The ones who are usually are
…		…
1415	specified in the variable.	1852	specified in the variable.
1416		1853
1417	You can make AnyEvent completely ignore this variable by deleting it	1854	You can make AnyEvent completely ignore this variable by deleting it
1418	before the first watcher gets created, e.g. with a C<BEGIN> block:	1855	before the first watcher gets created, e.g. with a C<BEGIN> block:
1419		1856
1420	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1857	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1421		1858
1422	use AnyEvent;	1859	use AnyEvent;
1423		1860
1424	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1861	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1425	be used to probe what backend is used and gain other information (which is	1862	be used to probe what backend is used and gain other information (which is
1426	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	1863	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1864	$ENV{PERL_ANYEGENT_STRICT}.
		1865
		1866
		1867	=head1 BUGS
		1868
		1869	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		1870	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		1871	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		1872	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
		1873	pronounced).
1427		1874
1428		1875
1429	=head1 SEE ALSO	1876	=head1 SEE ALSO
		1877
		1878	Utility functions: L<AnyEvent::Util>.
1430		1879
1431	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	1880	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1432	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	1881	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1433		1882
1434	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	1883	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1435	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	1884	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1436	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	1885	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1437	L<AnyEvent::Impl::POE>.	1886	L<AnyEvent::Impl::POE>.
1438		1887
		1888	Non-blocking file handles, sockets, TCP clients and
		1889	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1890
		1891	Asynchronous DNS: L<AnyEvent::DNS>.
		1892
1439	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	1893	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
1440		1894
1441	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1895	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1442		1896
1443		1897
1444	=head1 AUTHOR	1898	=head1 AUTHOR
1445		1899
1446	Marc Lehmann <schmorp@schmorp.de>	1900	Marc Lehmann <schmorp@schmorp.de>
1447	http://home.schmorp.de/	1901	http://home.schmorp.de/
1448		1902
1449	=cut	1903	=cut
1450		1904
1451	1	1905	1
1452		1906

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