ViewVC Help

View File | Revision Log | Show Annotations | Download File

/cvs/AnyEvent/lib/AnyEvent.pm

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.83 by root, Fri Apr 25 13:39:08 2008 UTC vs.
Revision 1.209 by root, Wed May 13 13:36:49 2009 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - provide framework for multiple event loops
4		4
5	EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops
6		6
7	=head1 SYNOPSIS	7	=head1 SYNOPSIS
8		8
9	use AnyEvent;	9	use AnyEvent;
10		10
		11	# file descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub {	12	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
		13
		14	# one-shot or repeating timers
		15	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
		16	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
		17
		18	print AnyEvent->now; # prints current event loop time
		19	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
		20
		21	# POSIX signal
		22	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
		23
		24	# child process exit
		25	my $w = AnyEvent->child (pid => $pid, cb => sub {
		26	my ($pid, $status) = @_;
12	...	27	...
13	});	28	});
14		29
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	30	# called when event loop idle (if applicable)
16	...	31	my $w = AnyEvent->idle (cb => sub { ... });
17	});
18		32
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	33	my $w = AnyEvent->condvar; # stores whether a condition was flagged
		34	$w->send; # wake up current and all future recv's
20	$w->wait; # enters "main loop" till $condvar gets ->broadcast	35	$w->recv; # enters "main loop" till $condvar gets ->send
21	$w->broadcast; # wake up current and all future wait's	36	# use a condvar in callback mode:
		37	$w->cb (sub { $_[0]->recv });
		38
		39	=head1 INTRODUCTION/TUTORIAL
		40
		41	This manpage is mainly a reference manual. If you are interested
		42	in a tutorial or some gentle introduction, have a look at the
		43	L<AnyEvent::Intro> manpage.
22		44
23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	45	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24		46
25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	47	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26	nowadays. So what is different about AnyEvent?	48	nowadays. So what is different about AnyEvent?
27		49
28	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of	50	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
29	policy> and AnyEvent is I<small and efficient>.	51	policy> and AnyEvent is I<small and efficient>.
30		52
31	First and foremost, I<AnyEvent is not an event model> itself, it only	53	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	54	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,	55	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,	56	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	57	only one event loop can be active at the same time in a process. AnyEvent
36	helps hiding the differences between those event loops.	58	cannot change this, but it can hide the differences between those event
		59	loops.
37		60
38	The goal of AnyEvent is to offer module authors the ability to do event	61	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	62	programming (waiting for I/O or timer events) without subscribing to a
40	religion, a way of living, and most importantly: without forcing your	63	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	64	module users into the same thing by forcing them to use the same event
42	model you use.	65	model you use.
43		66
44	For modules like POE or IO::Async (which is a total misnomer as it is	67	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	68	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	69	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	70	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	71	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.	72	module are I<also> forced to use the same event loop you use.
50		73
51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	74	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	75	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	76	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,	77	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	78	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	79	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	80	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).	81	to AnyEvent, too, so it is future-proof).
59		82
60	In addition to being free of having to use I<the one and only true event	83	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	84	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	85	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	86	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	87	offering the functionality that is necessary, in as thin as a wrapper as
65	technically possible.	88	technically possible.
66		89
		90	Of course, AnyEvent comes with a big (and fully optional!) toolbox
		91	of useful functionality, such as an asynchronous DNS resolver, 100%
		92	non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
		93	such as Windows) and lots of real-world knowledge and workarounds for
		94	platform bugs and differences.
		95
67	Of course, if you want lots of policy (this can arguably be somewhat	96	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	97	useful) and you want to force your users to use the one and only event
69	model, you should I<not> use this module.	98	model, you should I<not> use this module.
70
71		99
72	=head1 DESCRIPTION	100	=head1 DESCRIPTION
73		101
74	L<AnyEvent> provides an identical interface to multiple event loops. This	102	L<AnyEvent> provides an identical interface to multiple event loops. This
75	allows module authors to utilise an event loop without forcing module	103	allows module authors to utilise an event loop without forcing module
…		…
79	The interface itself is vaguely similar, but not identical to the L<Event>	107	The interface itself is vaguely similar, but not identical to the L<Event>
80	module.	108	module.
81		109
82	During the first call of any watcher-creation method, the module tries	110	During the first call of any watcher-creation method, the module tries
83	to detect the currently loaded event loop by probing whether one of the	111	to detect the currently loaded event loop by probing whether one of the
84	following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>,	112	following modules is already loaded: L<EV>,
85	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	113	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,
86	L<POE>. The first one found is used. If none are found, the module tries	114	L<POE>. The first one found is used. If none are found, the module tries
87	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	115	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl
88	adaptor should always succeed) in the order given. The first one that can	116	adaptor should always succeed) in the order given. The first one that can
89	be successfully loaded will be used. If, after this, still none could be	117	be successfully loaded will be used. If, after this, still none could be
…		…
103	starts using it, all bets are off. Maybe you should tell their authors to	131	starts using it, all bets are off. Maybe you should tell their authors to
104	use AnyEvent so their modules work together with others seamlessly...	132	use AnyEvent so their modules work together with others seamlessly...
105		133
106	The pure-perl implementation of AnyEvent is called	134	The pure-perl implementation of AnyEvent is called
107	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	135	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
108	explicitly.	136	explicitly and enjoy the high availability of that event loop :)
109		137
110	=head1 WATCHERS	138	=head1 WATCHERS
111		139
112	AnyEvent has the central concept of a I<watcher>, which is an object that	140	AnyEvent has the central concept of a I<watcher>, which is an object that
113	stores relevant data for each kind of event you are waiting for, such as	141	stores relevant data for each kind of event you are waiting for, such as
114	the callback to call, the filehandle to watch, etc.	142	the callback to call, the file handle to watch, etc.
115		143
116	These watchers are normal Perl objects with normal Perl lifetime. After	144	These watchers are normal Perl objects with normal Perl lifetime. After
117	creating a watcher it will immediately "watch" for events and invoke the	145	creating a watcher it will immediately "watch" for events and invoke the
118	callback when the event occurs (of course, only when the event model	146	callback when the event occurs (of course, only when the event model
119	is in control).	147	is in control).
120		148
		149	Note that B<callbacks must not permanently change global variables>
		150	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
		151	callbacks must not C<die> >>. The former is good programming practise in
		152	Perl and the latter stems from the fact that exception handling differs
		153	widely between event loops.
		154
121	To disable the watcher you have to destroy it (e.g. by setting the	155	To disable the watcher you have to destroy it (e.g. by setting the
122	variable you store it in to C<undef> or otherwise deleting all references	156	variable you store it in to C<undef> or otherwise deleting all references
123	to it).	157	to it).
124		158
125	All watchers are created by calling a method on the C<AnyEvent> class.	159	All watchers are created by calling a method on the C<AnyEvent> class.
…		…
127	Many watchers either are used with "recursion" (repeating timers for	161	Many watchers either are used with "recursion" (repeating timers for
128	example), or need to refer to their watcher object in other ways.	162	example), or need to refer to their watcher object in other ways.
129		163
130	An any way to achieve that is this pattern:	164	An any way to achieve that is this pattern:
131		165
132	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	166	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
133	# you can use $w here, for example to undef it	167	# you can use $w here, for example to undef it
134	undef $w;	168	undef $w;
135	});	169	});
136		170
137	Note that C<my $w; $w => combination. This is necessary because in Perl,	171	Note that C<my $w; $w => combination. This is necessary because in Perl,
138	my variables are only visible after the statement in which they are	172	my variables are only visible after the statement in which they are
139	declared.	173	declared.
140		174
141	=head2 I/O WATCHERS	175	=head2 I/O WATCHERS
142		176
143	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	177	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
144	with the following mandatory key-value pairs as arguments:	178	with the following mandatory key-value pairs as arguments:
145		179
146	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for	180	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch
		181	for events (AnyEvent might or might not keep a reference to this file
		182	handle). Note that only file handles pointing to things for which
		183	non-blocking operation makes sense are allowed. This includes sockets,
		184	most character devices, pipes, fifos and so on, but not for example files
		185	or block devices.
		186
147	events. C<poll> must be a string that is either C<r> or C<w>, which	187	C<poll> must be a string that is either C<r> or C<w>, which creates a
148	creates a watcher waiting for "r"eadable or "w"ritable events,	188	watcher waiting for "r"eadable or "w"ritable events, respectively.
		189
149	respectively. C<cb> is the callback to invoke each time the file handle	190	C<cb> is the callback to invoke each time the file handle becomes ready.
150	becomes ready.	191
		192	Although the callback might get passed parameters, their value and
		193	presence is undefined and you cannot rely on them. Portable AnyEvent
		194	callbacks cannot use arguments passed to I/O watcher callbacks.
151		195
152	The I/O watcher might use the underlying file descriptor or a copy of it.	196	The I/O watcher might use the underlying file descriptor or a copy of it.
153	It is not allowed to close a file handle as long as any watcher is active	197	You must not close a file handle as long as any watcher is active on the
154	on the underlying file descriptor.	198	underlying file descriptor.
155		199
156	Some event loops issue spurious readyness notifications, so you should	200	Some event loops issue spurious readyness notifications, so you should
157	always use non-blocking calls when reading/writing from/to your file	201	always use non-blocking calls when reading/writing from/to your file
158	handles.	202	handles.
159		203
160	Example:
161
162	# wait for readability of STDIN, then read a line and disable the watcher	204	Example: wait for readability of STDIN, then read a line and disable the
		205	watcher.
		206
163	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	207	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
164	chomp (my $input = <STDIN>);	208	chomp (my $input = <STDIN>);
165	warn "read: $input\n";	209	warn "read: $input\n";
166	undef $w;	210	undef $w;
167	});	211	});
…		…
170		214
171	You can create a time watcher by calling the C<< AnyEvent->timer >>	215	You can create a time watcher by calling the C<< AnyEvent->timer >>
172	method with the following mandatory arguments:	216	method with the following mandatory arguments:
173		217
174	C<after> specifies after how many seconds (fractional values are	218	C<after> specifies after how many seconds (fractional values are
175	supported) should the timer activate. C<cb> the callback to invoke in that	219	supported) the callback should be invoked. C<cb> is the callback to invoke
176	case.	220	in that case.
177		221
178	The timer callback will be invoked at most once: if you want a repeating	222	Although the callback might get passed parameters, their value and
179	timer you have to create a new watcher (this is a limitation by both Tk	223	presence is undefined and you cannot rely on them. Portable AnyEvent
180	and Glib).	224	callbacks cannot use arguments passed to time watcher callbacks.
181		225
182	Example:	226	The callback will normally be invoked once only. If you specify another
		227	parameter, C<interval>, as a strictly positive number (> 0), then the
		228	callback will be invoked regularly at that interval (in fractional
		229	seconds) after the first invocation. If C<interval> is specified with a
		230	false value, then it is treated as if it were missing.
183		231
		232	The callback will be rescheduled before invoking the callback, but no
		233	attempt is done to avoid timer drift in most backends, so the interval is
		234	only approximate.
		235
184	# fire an event after 7.7 seconds	236	Example: fire an event after 7.7 seconds.
		237
185	my $w = AnyEvent->timer (after => 7.7, cb => sub {	238	my $w = AnyEvent->timer (after => 7.7, cb => sub {
186	warn "timeout\n";	239	warn "timeout\n";
187	});	240	});
188		241
189	# to cancel the timer:	242	# to cancel the timer:
190	undef $w;	243	undef $w;
191		244
192	Example 2:
193
194	# fire an event after 0.5 seconds, then roughly every second	245	Example 2: fire an event after 0.5 seconds, then roughly every second.
195	my $w;
196		246
197	my $cb = sub {
198	# cancel the old timer while creating a new one
199	$w = AnyEvent->timer (after => 1, cb => $cb);	247	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		248	warn "timeout\n";
200	};	249	};
201
202	# start the "loop" by creating the first watcher
203	$w = AnyEvent->timer (after => 0.5, cb => $cb);
204		250
205	=head3 TIMING ISSUES	251	=head3 TIMING ISSUES
206		252
207	There are two ways to handle timers: based on real time (relative, "fire	253	There are two ways to handle timers: based on real time (relative, "fire
208	in 10 seconds") and based on wallclock time (absolute, "fire at 12	254	in 10 seconds") and based on wallclock time (absolute, "fire at 12
…		…
220	timers.	266	timers.
221		267
222	AnyEvent always prefers relative timers, if available, matching the	268	AnyEvent always prefers relative timers, if available, matching the
223	AnyEvent API.	269	AnyEvent API.
224		270
		271	AnyEvent has two additional methods that return the "current time":
		272
		273	=over 4
		274
		275	=item AnyEvent->time
		276
		277	This returns the "current wallclock time" as a fractional number of
		278	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
		279	return, and the result is guaranteed to be compatible with those).
		280
		281	It progresses independently of any event loop processing, i.e. each call
		282	will check the system clock, which usually gets updated frequently.
		283
		284	=item AnyEvent->now
		285
		286	This also returns the "current wallclock time", but unlike C<time>, above,
		287	this value might change only once per event loop iteration, depending on
		288	the event loop (most return the same time as C<time>, above). This is the
		289	time that AnyEvent's timers get scheduled against.
		290
		291	I<In almost all cases (in all cases if you don't care), this is the
		292	function to call when you want to know the current time.>
		293
		294	This function is also often faster then C<< AnyEvent->time >>, and
		295	thus the preferred method if you want some timestamp (for example,
		296	L<AnyEvent::Handle> uses this to update it's activity timeouts).
		297
		298	The rest of this section is only of relevance if you try to be very exact
		299	with your timing, you can skip it without bad conscience.
		300
		301	For a practical example of when these times differ, consider L<Event::Lib>
		302	and L<EV> and the following set-up:
		303
		304	The event loop is running and has just invoked one of your callback at
		305	time=500 (assume no other callbacks delay processing). In your callback,
		306	you wait a second by executing C<sleep 1> (blocking the process for a
		307	second) and then (at time=501) you create a relative timer that fires
		308	after three seconds.
		309
		310	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
		311	both return C<501>, because that is the current time, and the timer will
		312	be scheduled to fire at time=504 (C<501> + C<3>).
		313
		314	With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
		315	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
		316	last event processing phase started. With L<EV>, your timer gets scheduled
		317	to run at time=503 (C<500> + C<3>).
		318
		319	In one sense, L<Event::Lib> is more exact, as it uses the current time
		320	regardless of any delays introduced by event processing. However, most
		321	callbacks do not expect large delays in processing, so this causes a
		322	higher drift (and a lot more system calls to get the current time).
		323
		324	In another sense, L<EV> is more exact, as your timer will be scheduled at
		325	the same time, regardless of how long event processing actually took.
		326
		327	In either case, if you care (and in most cases, you don't), then you
		328	can get whatever behaviour you want with any event loop, by taking the
		329	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
		330	account.
		331
		332	=item AnyEvent->now_update
		333
		334	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		335	the current time for each loop iteration (see the discussion of L<<
		336	AnyEvent->now >>, above).
		337
		338	When a callback runs for a long time (or when the process sleeps), then
		339	this "current" time will differ substantially from the real time, which
		340	might affect timers and time-outs.
		341
		342	When this is the case, you can call this method, which will update the
		343	event loop's idea of "current time".
		344
		345	Note that updating the time I<might> cause some events to be handled.
		346
		347	=back
		348
225	=head2 SIGNAL WATCHERS	349	=head2 SIGNAL WATCHERS
226		350
227	You can watch for signals using a signal watcher, C<signal> is the signal	351	You can watch for signals using a signal watcher, C<signal> is the signal
228	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to	352	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
229	be invoked whenever a signal occurs.	353	callback to be invoked whenever a signal occurs.
230		354
		355	Although the callback might get passed parameters, their value and
		356	presence is undefined and you cannot rely on them. Portable AnyEvent
		357	callbacks cannot use arguments passed to signal watcher callbacks.
		358
231	Multiple signal occurances can be clumped together into one callback	359	Multiple signal occurrences can be clumped together into one callback
232	invocation, and callback invocation will be synchronous. synchronous means	360	invocation, and callback invocation will be synchronous. Synchronous means
233	that it might take a while until the signal gets handled by the process,	361	that it might take a while until the signal gets handled by the process,
234	but it is guarenteed not to interrupt any other callbacks.	362	but it is guaranteed not to interrupt any other callbacks.
235		363
236	The main advantage of using these watchers is that you can share a signal	364	The main advantage of using these watchers is that you can share a signal
237	between multiple watchers.	365	between multiple watchers.
238		366
239	This watcher might use C<%SIG>, so programs overwriting those signals	367	This watcher might use C<%SIG>, so programs overwriting those signals
…		…
246	=head2 CHILD PROCESS WATCHERS	374	=head2 CHILD PROCESS WATCHERS
247		375
248	You can also watch on a child process exit and catch its exit status.	376	You can also watch on a child process exit and catch its exit status.
249		377
250	The child process is specified by the C<pid> argument (if set to C<0>, it	378	The child process is specified by the C<pid> argument (if set to C<0>, it
251	watches for any child process exit). The watcher will trigger as often	379	watches for any child process exit). The watcher will triggered only when
252	as status change for the child are received. This works by installing a	380	the child process has finished and an exit status is available, not on
253	signal handler for C<SIGCHLD>. The callback will be called with the pid	381	any trace events (stopped/continued).
254	and exit status (as returned by waitpid).	382
		383	The callback will be called with the pid and exit status (as returned by
		384	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		385	callback arguments.
		386
		387	This watcher type works by installing a signal handler for C<SIGCHLD>,
		388	and since it cannot be shared, nothing else should use SIGCHLD or reap
		389	random child processes (waiting for specific child processes, e.g. inside
		390	C<system>, is just fine).
255		391
256	There is a slight catch to child watchers, however: you usually start them	392	There is a slight catch to child watchers, however: you usually start them
257	I<after> the child process was created, and this means the process could	393	I<after> the child process was created, and this means the process could
258	have exited already (and no SIGCHLD will be sent anymore).	394	have exited already (and no SIGCHLD will be sent anymore).
259		395
…		…
265	AnyEvent program, you I<have> to create at least one watcher before you	401	AnyEvent program, you I<have> to create at least one watcher before you
266	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	402	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
267		403
268	Example: fork a process and wait for it	404	Example: fork a process and wait for it
269		405
270	my $done = AnyEvent->condvar;	406	my $done = AnyEvent->condvar;
271		407
272	AnyEvent::detect; # force event module to be initialised
273
274	my $pid = fork or exit 5;	408	my $pid = fork or exit 5;
275		409
276	my $w = AnyEvent->child (	410	my $w = AnyEvent->child (
277	pid => $pid,	411	pid => $pid,
278	cb => sub {	412	cb => sub {
279	my ($pid, $status) = @_;	413	my ($pid, $status) = @_;
280	warn "pid $pid exited with status $status";	414	warn "pid $pid exited with status $status";
281	$done->broadcast;	415	$done->send;
282	},	416	},
283	);	417	);
284		418
285	# do something else, then wait for process exit	419	# do something else, then wait for process exit
286	$done->wait;	420	$done->recv;
		421
		422	=head2 IDLE WATCHERS
		423
		424	Sometimes there is a need to do something, but it is not so important
		425	to do it instantly, but only when there is nothing better to do. This
		426	"nothing better to do" is usually defined to be "no other events need
		427	attention by the event loop".
		428
		429	Idle watchers ideally get invoked when the event loop has nothing
		430	better to do, just before it would block the process to wait for new
		431	events. Instead of blocking, the idle watcher is invoked.
		432
		433	Most event loops unfortunately do not really support idle watchers (only
		434	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		435	will simply call the callback "from time to time".
		436
		437	Example: read lines from STDIN, but only process them when the
		438	program is otherwise idle:
		439
		440	my @lines; # read data
		441	my $idle_w;
		442	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		443	push @lines, scalar <STDIN>;
		444
		445	# start an idle watcher, if not already done
		446	$idle_w ||= AnyEvent->idle (cb => sub {
		447	# handle only one line, when there are lines left
		448	if (my $line = shift @lines) {
		449	print "handled when idle: $line";
		450	} else {
		451	# otherwise disable the idle watcher again
		452	undef $idle_w;
		453	}
		454	});
		455	});
287		456
288	=head2 CONDITION VARIABLES	457	=head2 CONDITION VARIABLES
289		458
		459	If you are familiar with some event loops you will know that all of them
		460	require you to run some blocking "loop", "run" or similar function that
		461	will actively watch for new events and call your callbacks.
		462
		463	AnyEvent is different, it expects somebody else to run the event loop and
		464	will only block when necessary (usually when told by the user).
		465
		466	The instrument to do that is called a "condition variable", so called
		467	because they represent a condition that must become true.
		468
290	Condition variables can be created by calling the C<< AnyEvent->condvar >>	469	Condition variables can be created by calling the C<< AnyEvent->condvar
291	method without any arguments.	470	>> method, usually without arguments. The only argument pair allowed is
292		471
293	A condition variable waits for a condition - precisely that the C<<	472	C<cb>, which specifies a callback to be called when the condition variable
294	->broadcast >> method has been called.	473	becomes true, with the condition variable as the first argument (but not
		474	the results).
295		475
296	They are very useful to signal that a condition has been fulfilled, for	476	After creation, the condition variable is "false" until it becomes "true"
		477	by calling the C<send> method (or calling the condition variable as if it
		478	were a callback, read about the caveats in the description for the C<<
		479	->send >> method).
		480
		481	Condition variables are similar to callbacks, except that you can
		482	optionally wait for them. They can also be called merge points - points
		483	in time where multiple outstanding events have been processed. And yet
		484	another way to call them is transactions - each condition variable can be
		485	used to represent a transaction, which finishes at some point and delivers
		486	a result.
		487
		488	Condition variables are very useful to signal that something has finished,
297	example, if you write a module that does asynchronous http requests,	489	for example, if you write a module that does asynchronous http requests,
298	then a condition variable would be the ideal candidate to signal the	490	then a condition variable would be the ideal candidate to signal the
299	availability of results.	491	availability of results. The user can either act when the callback is
		492	called or can synchronously C<< ->recv >> for the results.
300		493
301	You can also use condition variables to block your main program until	494	You can also use them to simulate traditional event loops - for example,
302	an event occurs - for example, you could C<< ->wait >> in your main	495	you can block your main program until an event occurs - for example, you
303	program until the user clicks the Quit button in your app, which would C<<	496	could C<< ->recv >> in your main program until the user clicks the Quit
304	->broadcast >> the "quit" event.	497	button of your app, which would C<< ->send >> the "quit" event.
305		498
306	Note that condition variables recurse into the event loop - if you have	499	Note that condition variables recurse into the event loop - if you have
307	two pirces of code that call C<< ->wait >> in a round-robbin fashion, you	500	two pieces of code that call C<< ->recv >> in a round-robin fashion, you
308	lose. Therefore, condition variables are good to export to your caller, but	501	lose. Therefore, condition variables are good to export to your caller, but
309	you should avoid making a blocking wait yourself, at least in callbacks,	502	you should avoid making a blocking wait yourself, at least in callbacks,
310	as this asks for trouble.	503	as this asks for trouble.
311		504
312	This object has two methods:	505	Condition variables are represented by hash refs in perl, and the keys
		506	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
		507	easy (it is often useful to build your own transaction class on top of
		508	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
		509	it's C<new> method in your own C<new> method.
		510
		511	There are two "sides" to a condition variable - the "producer side" which
		512	eventually calls C<< -> send >>, and the "consumer side", which waits
		513	for the send to occur.
		514
		515	Example: wait for a timer.
		516
		517	# wait till the result is ready
		518	my $result_ready = AnyEvent->condvar;
		519
		520	# do something such as adding a timer
		521	# or socket watcher the calls $result_ready->send
		522	# when the "result" is ready.
		523	# in this case, we simply use a timer:
		524	my $w = AnyEvent->timer (
		525	after => 1,
		526	cb => sub { $result_ready->send },
		527	);
		528
		529	# this "blocks" (while handling events) till the callback
		530	# calls send
		531	$result_ready->recv;
		532
		533	Example: wait for a timer, but take advantage of the fact that
		534	condition variables are also code references.
		535
		536	my $done = AnyEvent->condvar;
		537	my $delay = AnyEvent->timer (after => 5, cb => $done);
		538	$done->recv;
		539
		540	Example: Imagine an API that returns a condvar and doesn't support
		541	callbacks. This is how you make a synchronous call, for example from
		542	the main program:
		543
		544	use AnyEvent::CouchDB;
		545
		546	...
		547
		548	my @info = $couchdb->info->recv;
		549
		550	And this is how you would just ste a callback to be called whenever the
		551	results are available:
		552
		553	$couchdb->info->cb (sub {
		554	my @info = $_[0]->recv;
		555	});
		556
		557	=head3 METHODS FOR PRODUCERS
		558
		559	These methods should only be used by the producing side, i.e. the
		560	code/module that eventually sends the signal. Note that it is also
		561	the producer side which creates the condvar in most cases, but it isn't
		562	uncommon for the consumer to create it as well.
313		563
314	=over 4	564	=over 4
315		565
		566	=item $cv->send (...)
		567
		568	Flag the condition as ready - a running C<< ->recv >> and all further
		569	calls to C<recv> will (eventually) return after this method has been
		570	called. If nobody is waiting the send will be remembered.
		571
		572	If a callback has been set on the condition variable, it is called
		573	immediately from within send.
		574
		575	Any arguments passed to the C<send> call will be returned by all
		576	future C<< ->recv >> calls.
		577
		578	Condition variables are overloaded so one can call them directly
		579	(as a code reference). Calling them directly is the same as calling
		580	C<send>. Note, however, that many C-based event loops do not handle
		581	overloading, so as tempting as it may be, passing a condition variable
		582	instead of a callback does not work. Both the pure perl and EV loops
		583	support overloading, however, as well as all functions that use perl to
		584	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
		585	example).
		586
		587	=item $cv->croak ($error)
		588
		589	Similar to send, but causes all call's to C<< ->recv >> to invoke
		590	C<Carp::croak> with the given error message/object/scalar.
		591
		592	This can be used to signal any errors to the condition variable
		593	user/consumer.
		594
		595	=item $cv->begin ([group callback])
		596
316	=item $cv->wait	597	=item $cv->end
317		598
318	Wait (blocking if necessary) until the C<< ->broadcast >> method has been	599	These two methods are EXPERIMENTAL and MIGHT CHANGE.
		600
		601	These two methods can be used to combine many transactions/events into
		602	one. For example, a function that pings many hosts in parallel might want
		603	to use a condition variable for the whole process.
		604
		605	Every call to C<< ->begin >> will increment a counter, and every call to
		606	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
		607	>>, the (last) callback passed to C<begin> will be executed. That callback
		608	is I<supposed> to call C<< ->send >>, but that is not required. If no
		609	callback was set, C<send> will be called without any arguments.
		610
		611	Let's clarify this with the ping example:
		612
		613	my $cv = AnyEvent->condvar;
		614
		615	my %result;
		616	$cv->begin (sub { $cv->send (\%result) });
		617
		618	for my $host (@list_of_hosts) {
		619	$cv->begin;
		620	ping_host_then_call_callback $host, sub {
		621	$result{$host} = ...;
		622	$cv->end;
		623	};
		624	}
		625
		626	$cv->end;
		627
		628	This code fragment supposedly pings a number of hosts and calls
		629	C<send> after results for all then have have been gathered - in any
		630	order. To achieve this, the code issues a call to C<begin> when it starts
		631	each ping request and calls C<end> when it has received some result for
		632	it. Since C<begin> and C<end> only maintain a counter, the order in which
		633	results arrive is not relevant.
		634
		635	There is an additional bracketing call to C<begin> and C<end> outside the
		636	loop, which serves two important purposes: first, it sets the callback
		637	to be called once the counter reaches C<0>, and second, it ensures that
		638	C<send> is called even when C<no> hosts are being pinged (the loop
		639	doesn't execute once).
		640
		641	This is the general pattern when you "fan out" into multiple subrequests:
		642	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>
		643	is called at least once, and then, for each subrequest you start, call
		644	C<begin> and for each subrequest you finish, call C<end>.
		645
		646	=back
		647
		648	=head3 METHODS FOR CONSUMERS
		649
		650	These methods should only be used by the consuming side, i.e. the
		651	code awaits the condition.
		652
		653	=over 4
		654
		655	=item $cv->recv
		656
		657	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
319	called on c<$cv>, while servicing other watchers normally.	658	>> methods have been called on c<$cv>, while servicing other watchers
		659	normally.
320		660
321	You can only wait once on a condition - additional calls will return	661	You can only wait once on a condition - additional calls are valid but
322	immediately.	662	will return immediately.
		663
		664	If an error condition has been set by calling C<< ->croak >>, then this
		665	function will call C<croak>.
		666
		667	In list context, all parameters passed to C<send> will be returned,
		668	in scalar context only the first one will be returned.
323		669
324	Not all event models support a blocking wait - some die in that case	670	Not all event models support a blocking wait - some die in that case
325	(programs might want to do that to stay interactive), so I<if you are	671	(programs might want to do that to stay interactive), so I<if you are
326	using this from a module, never require a blocking wait>, but let the	672	using this from a module, never require a blocking wait>, but let the
327	caller decide whether the call will block or not (for example, by coupling	673	caller decide whether the call will block or not (for example, by coupling
328	condition variables with some kind of request results and supporting	674	condition variables with some kind of request results and supporting
329	callbacks so the caller knows that getting the result will not block,	675	callbacks so the caller knows that getting the result will not block,
330	while still suppporting blocking waits if the caller so desires).	676	while still supporting blocking waits if the caller so desires).
331		677
332	Another reason I<never> to C<< ->wait >> in a module is that you cannot	678	Another reason I<never> to C<< ->recv >> in a module is that you cannot
333	sensibly have two C<< ->wait >>'s in parallel, as that would require	679	sensibly have two C<< ->recv >>'s in parallel, as that would require
334	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	680	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
335	can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and	681	can supply.
336	L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
337	from different coroutines, however).
338		682
339	=item $cv->broadcast	683	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
		684	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
		685	versions and also integrates coroutines into AnyEvent, making blocking
		686	C<< ->recv >> calls perfectly safe as long as they are done from another
		687	coroutine (one that doesn't run the event loop).
340		688
341	Flag the condition as ready - a running C<< ->wait >> and all further	689	You can ensure that C<< -recv >> never blocks by setting a callback and
342	calls to C<wait> will (eventually) return after this method has been	690	only calling C<< ->recv >> from within that callback (or at a later
343	called. If nobody is waiting the broadcast will be remembered..	691	time). This will work even when the event loop does not support blocking
		692	waits otherwise.
		693
		694	=item $bool = $cv->ready
		695
		696	Returns true when the condition is "true", i.e. whether C<send> or
		697	C<croak> have been called.
		698
		699	=item $cb = $cv->cb ($cb->($cv))
		700
		701	This is a mutator function that returns the callback set and optionally
		702	replaces it before doing so.
		703
		704	The callback will be called when the condition becomes "true", i.e. when
		705	C<send> or C<croak> are called, with the only argument being the condition
		706	variable itself. Calling C<recv> inside the callback or at any later time
		707	is guaranteed not to block.
344		708
345	=back	709	=back
346
347	Example:
348
349	# wait till the result is ready
350	my $result_ready = AnyEvent->condvar;
351
352	# do something such as adding a timer
353	# or socket watcher the calls $result_ready->broadcast
354	# when the "result" is ready.
355	# in this case, we simply use a timer:
356	my $w = AnyEvent->timer (
357	after => 1,
358	cb => sub { $result_ready->broadcast },
359	);
360
361	# this "blocks" (while handling events) till the watcher
362	# calls broadcast
363	$result_ready->wait;
364		710
365	=head1 GLOBAL VARIABLES AND FUNCTIONS	711	=head1 GLOBAL VARIABLES AND FUNCTIONS
366		712
367	=over 4	713	=over 4
368		714
…		…
374	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	720	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
375	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	721	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
376		722
377	The known classes so far are:	723	The known classes so far are:
378		724
379	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
380	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
381	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).	725	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
382	AnyEvent::Impl::Event based on Event, second best choice.	726	AnyEvent::Impl::Event based on Event, second best choice.
		727	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
383	AnyEvent::Impl::Glib based on Glib, third-best choice.	728	AnyEvent::Impl::Glib based on Glib, third-best choice.
384	AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable.
385	AnyEvent::Impl::Tk based on Tk, very bad choice.	729	AnyEvent::Impl::Tk based on Tk, very bad choice.
386	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).	730	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
387	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	731	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
388	AnyEvent::Impl::POE based on POE, not generic enough for full support.	732	AnyEvent::Impl::POE based on POE, not generic enough for full support.
389		733
…		…
402	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	746	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
403	if necessary. You should only call this function right before you would	747	if necessary. You should only call this function right before you would
404	have created an AnyEvent watcher anyway, that is, as late as possible at	748	have created an AnyEvent watcher anyway, that is, as late as possible at
405	runtime.	749	runtime.
406		750
		751	=item $guard = AnyEvent::post_detect { BLOCK }
		752
		753	Arranges for the code block to be executed as soon as the event model is
		754	autodetected (or immediately if this has already happened).
		755
		756	If called in scalar or list context, then it creates and returns an object
		757	that automatically removes the callback again when it is destroyed. See
		758	L<Coro::BDB> for a case where this is useful.
		759
		760	=item @AnyEvent::post_detect
		761
		762	If there are any code references in this array (you can C<push> to it
		763	before or after loading AnyEvent), then they will called directly after
		764	the event loop has been chosen.
		765
		766	You should check C<$AnyEvent::MODEL> before adding to this array, though:
		767	if it contains a true value then the event loop has already been detected,
		768	and the array will be ignored.
		769
		770	Best use C<AnyEvent::post_detect { BLOCK }> instead.
		771
407	=back	772	=back
408		773
409	=head1 WHAT TO DO IN A MODULE	774	=head1 WHAT TO DO IN A MODULE
410		775
411	As a module author, you should C<use AnyEvent> and call AnyEvent methods	776	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
414	Be careful when you create watchers in the module body - AnyEvent will	779	Be careful when you create watchers in the module body - AnyEvent will
415	decide which event module to use as soon as the first method is called, so	780	decide which event module to use as soon as the first method is called, so
416	by calling AnyEvent in your module body you force the user of your module	781	by calling AnyEvent in your module body you force the user of your module
417	to load the event module first.	782	to load the event module first.
418		783
419	Never call C<< ->wait >> on a condition variable unless you I<know> that	784	Never call C<< ->recv >> on a condition variable unless you I<know> that
420	the C<< ->broadcast >> method has been called on it already. This is	785	the C<< ->send >> method has been called on it already. This is
421	because it will stall the whole program, and the whole point of using	786	because it will stall the whole program, and the whole point of using
422	events is to stay interactive.	787	events is to stay interactive.
423		788
424	It is fine, however, to call C<< ->wait >> when the user of your module	789	It is fine, however, to call C<< ->recv >> when the user of your module
425	requests it (i.e. if you create a http request object ad have a method	790	requests it (i.e. if you create a http request object ad have a method
426	called C<results> that returns the results, it should call C<< ->wait >>	791	called C<results> that returns the results, it should call C<< ->recv >>
427	freely, as the user of your module knows what she is doing. always).	792	freely, as the user of your module knows what she is doing. always).
428		793
429	=head1 WHAT TO DO IN THE MAIN PROGRAM	794	=head1 WHAT TO DO IN THE MAIN PROGRAM
430		795
431	There will always be a single main program - the only place that should	796	There will always be a single main program - the only place that should
…		…
433		798
434	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	799	If it doesn't care, it can just "use AnyEvent" and use it itself, or not
435	do anything special (it does not need to be event-based) and let AnyEvent	800	do anything special (it does not need to be event-based) and let AnyEvent
436	decide which implementation to chose if some module relies on it.	801	decide which implementation to chose if some module relies on it.
437		802
438	If the main program relies on a specific event model. For example, in	803	If the main program relies on a specific event model - for example, in
439	Gtk2 programs you have to rely on the Glib module. You should load the	804	Gtk2 programs you have to rely on the Glib module - you should load the
440	event module before loading AnyEvent or any module that uses it: generally	805	event module before loading AnyEvent or any module that uses it: generally
441	speaking, you should load it as early as possible. The reason is that	806	speaking, you should load it as early as possible. The reason is that
442	modules might create watchers when they are loaded, and AnyEvent will	807	modules might create watchers when they are loaded, and AnyEvent will
443	decide on the event model to use as soon as it creates watchers, and it	808	decide on the event model to use as soon as it creates watchers, and it
444	might chose the wrong one unless you load the correct one yourself.	809	might chose the wrong one unless you load the correct one yourself.
445		810
446	You can chose to use a rather inefficient pure-perl implementation by	811	You can chose to use a pure-perl implementation by loading the
447	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	812	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
448	behaviour everywhere, but letting AnyEvent chose is generally better.	813	everywhere, but letting AnyEvent chose the model is generally better.
		814
		815	=head2 MAINLOOP EMULATION
		816
		817	Sometimes (often for short test scripts, or even standalone programs who
		818	only want to use AnyEvent), you do not want to run a specific event loop.
		819
		820	In that case, you can use a condition variable like this:
		821
		822	AnyEvent->condvar->recv;
		823
		824	This has the effect of entering the event loop and looping forever.
		825
		826	Note that usually your program has some exit condition, in which case
		827	it is better to use the "traditional" approach of storing a condition
		828	variable somewhere, waiting for it, and sending it when the program should
		829	exit cleanly.
		830
		831
		832	=head1 OTHER MODULES
		833
		834	The following is a non-exhaustive list of additional modules that use
		835	AnyEvent and can therefore be mixed easily with other AnyEvent modules
		836	in the same program. Some of the modules come with AnyEvent, some are
		837	available via CPAN.
		838
		839	=over 4
		840
		841	=item L<AnyEvent::Util>
		842
		843	Contains various utility functions that replace often-used but blocking
		844	functions such as C<inet_aton> by event-/callback-based versions.
		845
		846	=item L<AnyEvent::Socket>
		847
		848	Provides various utility functions for (internet protocol) sockets,
		849	addresses and name resolution. Also functions to create non-blocking tcp
		850	connections or tcp servers, with IPv6 and SRV record support and more.
		851
		852	=item L<AnyEvent::Handle>
		853
		854	Provide read and write buffers, manages watchers for reads and writes,
		855	supports raw and formatted I/O, I/O queued and fully transparent and
		856	non-blocking SSL/TLS.
		857
		858	=item L<AnyEvent::DNS>
		859
		860	Provides rich asynchronous DNS resolver capabilities.
		861
		862	=item L<AnyEvent::HTTP>
		863
		864	A simple-to-use HTTP library that is capable of making a lot of concurrent
		865	HTTP requests.
		866
		867	=item L<AnyEvent::HTTPD>
		868
		869	Provides a simple web application server framework.
		870
		871	=item L<AnyEvent::FastPing>
		872
		873	The fastest ping in the west.
		874
		875	=item L<AnyEvent::DBI>
		876
		877	Executes L<DBI> requests asynchronously in a proxy process.
		878
		879	=item L<AnyEvent::AIO>
		880
		881	Truly asynchronous I/O, should be in the toolbox of every event
		882	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		883	together.
		884
		885	=item L<AnyEvent::BDB>
		886
		887	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		888	L<BDB> and AnyEvent together.
		889
		890	=item L<AnyEvent::GPSD>
		891
		892	A non-blocking interface to gpsd, a daemon delivering GPS information.
		893
		894	=item L<AnyEvent::IGS>
		895
		896	A non-blocking interface to the Internet Go Server protocol (used by
		897	L<App::IGS>).
		898
		899	=item L<AnyEvent::IRC>
		900
		901	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		902
		903	=item L<Net::XMPP2>
		904
		905	AnyEvent based XMPP (Jabber protocol) module family.
		906
		907	=item L<Net::FCP>
		908
		909	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
		910	of AnyEvent.
		911
		912	=item L<Event::ExecFlow>
		913
		914	High level API for event-based execution flow control.
		915
		916	=item L<Coro>
		917
		918	Has special support for AnyEvent via L<Coro::AnyEvent>.
		919
		920	=item L<IO::Lambda>
		921
		922	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
		923
		924	=back
449		925
450	=cut	926	=cut
451		927
452	package AnyEvent;	928	package AnyEvent;
453		929
454	no warnings;	930	no warnings;
455	use strict;	931	use strict qw(vars subs);
456		932
457	use Carp;	933	use Carp;
458		934
459	our $VERSION = '3.3';	935	our $VERSION = 4.41;
460	our $MODEL;	936	our $MODEL;
461		937
462	our $AUTOLOAD;	938	our $AUTOLOAD;
463	our @ISA;	939	our @ISA;
464		940
		941	our @REGISTRY;
		942
		943	our $WIN32;
		944
		945	BEGIN {
		946	my $win32 = ! ! ($^O =~ /mswin32/i);
		947	eval "sub WIN32(){ $win32 }";
		948	}
		949
465	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	950	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
466		951
467	our @REGISTRY;	952	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
		953
		954	{
		955	my $idx;
		956	$PROTOCOL{$_} = ++$idx
		957	for reverse split /\s*,\s*/,
		958	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
		959	}
468		960
469	my @models = (	961	my @models = (
470	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
471	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
472	[EV:: => AnyEvent::Impl::EV::],	962	[EV:: => AnyEvent::Impl::EV::],
473	[Event:: => AnyEvent::Impl::Event::],	963	[Event:: => AnyEvent::Impl::Event::],
474	[Glib:: => AnyEvent::Impl::Glib::],
475	[Tk:: => AnyEvent::Impl::Tk::],
476	[Wx:: => AnyEvent::Impl::POE::],
477	[Prima:: => AnyEvent::Impl::POE::],
478	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	964	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
479	# everything below here will not be autoprobed as the pureperl backend should work everywhere	965	# everything below here will not be autoprobed
		966	# as the pureperl backend should work everywhere
		967	# and is usually faster
		968	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		969	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
480	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	970	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
481	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	971	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
482	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	972	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
		973	[Wx:: => AnyEvent::Impl::POE::],
		974	[Prima:: => AnyEvent::Impl::POE::],
483	);	975	);
484		976
485	our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY);	977	our %method = map +($_ => 1),
		978	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
		979
		980	our @post_detect;
		981
		982	sub post_detect(&) {
		983	my ($cb) = @_;
		984
		985	if ($MODEL) {
		986	$cb->();
		987
		988	1
		989	} else {
		990	push @post_detect, $cb;
		991
		992	defined wantarray
		993	? bless \$cb, "AnyEvent::Util::postdetect"
		994	: ()
		995	}
		996	}
		997
		998	sub AnyEvent::Util::postdetect::DESTROY {
		999	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1000	}
486		1001
487	sub detect() {	1002	sub detect() {
488	unless ($MODEL) {	1003	unless ($MODEL) {
489	no strict 'refs';	1004	no strict 'refs';
		1005	local $SIG{__DIE__};
490		1006
491	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1007	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
492	my $model = "AnyEvent::Impl::$1";	1008	my $model = "AnyEvent::Impl::$1";
493	if (eval "require $model") {	1009	if (eval "require $model") {
494	$MODEL = $model;	1010	$MODEL = $model;
…		…
524	last;	1040	last;
525	}	1041	}
526	}	1042	}
527		1043
528	$MODEL	1044	$MODEL
529	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib.";	1045	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
530	}	1046	}
531	}	1047	}
532		1048
		1049	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1050
533	unshift @ISA, $MODEL;	1051	unshift @ISA, $MODEL;
534	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1052
		1053	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1054
		1055	(shift @post_detect)->() while @post_detect;
535	}	1056	}
536		1057
537	$MODEL	1058	$MODEL
538	}	1059	}
539		1060
…		…
547		1068
548	my $class = shift;	1069	my $class = shift;
549	$class->$func (@_);	1070	$class->$func (@_);
550	}	1071	}
551		1072
		1073	# utility function to dup a filehandle. this is used by many backends
		1074	# to support binding more than one watcher per filehandle (they usually
		1075	# allow only one watcher per fd, so we dup it to get a different one).
		1076	sub _dupfh($$$$) {
		1077	my ($poll, $fh, $r, $w) = @_;
		1078
		1079	# cygwin requires the fh mode to be matching, unix doesn't
		1080	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		1081	: $poll eq "w" ? ($w, ">")
		1082	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		1083
		1084	open my $fh2, "$mode&" . fileno $fh
		1085	or die "cannot dup() filehandle: $!,";
		1086
		1087	# we assume CLOEXEC is already set by perl in all important cases
		1088
		1089	($fh2, $rw)
		1090	}
		1091
552	package AnyEvent::Base;	1092	package AnyEvent::Base;
553		1093
		1094	# default implementations for many methods
		1095
		1096	BEGIN {
		1097	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1098	*_time = \&Time::HiRes::time;
		1099	# if (eval "use POSIX (); (POSIX::times())...
		1100	} else {
		1101	*_time = sub { time }; # epic fail
		1102	}
		1103	}
		1104
		1105	sub time { _time }
		1106	sub now { _time }
		1107	sub now_update { }
		1108
554	# default implementation for ->condvar, ->wait, ->broadcast	1109	# default implementation for ->condvar
555		1110
556	sub condvar {	1111	sub condvar {
557	bless \my $flag, "AnyEvent::Base::CondVar"	1112	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
558	}
559
560	sub AnyEvent::Base::CondVar::broadcast {
561	${$_[0]}++;
562	}
563
564	sub AnyEvent::Base::CondVar::wait {
565	AnyEvent->one_event while !${$_[0]};
566	}	1113	}
567		1114
568	# default implementation for ->signal	1115	# default implementation for ->signal
569		1116
570	our %SIG_CB;	1117	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1118
		1119	sub _signal_exec {
		1120	sysread $SIGPIPE_R, my $dummy, 4;
		1121
		1122	while (%SIG_EV) {
		1123	for (keys %SIG_EV) {
		1124	delete $SIG_EV{$_};
		1125	$_->() for values %{ $SIG_CB{$_} || {} };
		1126	}
		1127	}
		1128	}
571		1129
572	sub signal {	1130	sub signal {
573	my (undef, %arg) = @_;	1131	my (undef, %arg) = @_;
574		1132
		1133	unless ($SIGPIPE_R) {
		1134	require Fcntl;
		1135
		1136	if (AnyEvent::WIN32) {
		1137	require AnyEvent::Util;
		1138
		1139	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1140	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1141	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1142	} else {
		1143	pipe $SIGPIPE_R, $SIGPIPE_W;
		1144	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1145	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1146	}
		1147
		1148	$SIGPIPE_R
		1149	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1150
		1151	# not strictly required, as $^F is normally 2, but let's make sure...
		1152	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1153	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1154
		1155	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1156	}
		1157
575	my $signal = uc $arg{signal}	1158	my $signal = uc $arg{signal}
576	or Carp::croak "required option 'signal' is missing";	1159	or Carp::croak "required option 'signal' is missing";
577		1160
578	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1161	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
579	$SIG{$signal} ||= sub {	1162	$SIG{$signal} ||= sub {
580	$_->() for values %{ $SIG_CB{$signal} || {} };	1163	local $!;
		1164	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1165	undef $SIG_EV{$signal};
581	};	1166	};
582		1167
583	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1168	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
584	}	1169	}
585		1170
586	sub AnyEvent::Base::Signal::DESTROY {	1171	sub AnyEvent::Base::signal::DESTROY {
587	my ($signal, $cb) = @{$_[0]};	1172	my ($signal, $cb) = @{$_[0]};
588		1173
589	delete $SIG_CB{$signal}{$cb};	1174	delete $SIG_CB{$signal}{$cb};
590		1175
591	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1176	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };
…		…
623	or Carp::croak "required option 'pid' is missing";	1208	or Carp::croak "required option 'pid' is missing";
624		1209
625	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1210	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
626		1211
627	unless ($WNOHANG) {	1212	unless ($WNOHANG) {
628	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1;	1213	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
629	}	1214	}
630		1215
631	unless ($CHLD_W) {	1216	unless ($CHLD_W) {
632	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1217	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
633	# child could be a zombie already, so make at least one round	1218	# child could be a zombie already, so make at least one round
634	&_sigchld;	1219	&_sigchld;
635	}	1220	}
636		1221
637	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1222	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
638	}	1223	}
639		1224
640	sub AnyEvent::Base::Child::DESTROY {	1225	sub AnyEvent::Base::child::DESTROY {
641	my ($pid, $cb) = @{$_[0]};	1226	my ($pid, $cb) = @{$_[0]};
642		1227
643	delete $PID_CB{$pid}{$cb};	1228	delete $PID_CB{$pid}{$cb};
644	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1229	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
645		1230
646	undef $CHLD_W unless keys %PID_CB;	1231	undef $CHLD_W unless keys %PID_CB;
647	}	1232	}
		1233
		1234	# idle emulation is done by simply using a timer, regardless
		1235	# of whether the proces sis idle or not, and not letting
		1236	# the callback use more than 50% of the time.
		1237	sub idle {
		1238	my (undef, %arg) = @_;
		1239
		1240	my ($cb, $w, $rcb) = $arg{cb};
		1241
		1242	$rcb = sub {
		1243	if ($cb) {
		1244	$w = _time;
		1245	&$cb;
		1246	$w = _time - $w;
		1247
		1248	# never use more then 50% of the time for the idle watcher,
		1249	# within some limits
		1250	$w = 0.0001 if $w < 0.0001;
		1251	$w = 5 if $w > 5;
		1252
		1253	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1254	} else {
		1255	# clean up...
		1256	undef $w;
		1257	undef $rcb;
		1258	}
		1259	};
		1260
		1261	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1262
		1263	bless \\$cb, "AnyEvent::Base::idle"
		1264	}
		1265
		1266	sub AnyEvent::Base::idle::DESTROY {
		1267	undef $${$_[0]};
		1268	}
		1269
		1270	package AnyEvent::CondVar;
		1271
		1272	our @ISA = AnyEvent::CondVar::Base::;
		1273
		1274	package AnyEvent::CondVar::Base;
		1275
		1276	use overload
		1277	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		1278	fallback => 1;
		1279
		1280	sub _send {
		1281	# nop
		1282	}
		1283
		1284	sub send {
		1285	my $cv = shift;
		1286	$cv->{_ae_sent} = [@_];
		1287	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		1288	$cv->_send;
		1289	}
		1290
		1291	sub croak {
		1292	$_[0]{_ae_croak} = $_[1];
		1293	$_[0]->send;
		1294	}
		1295
		1296	sub ready {
		1297	$_[0]{_ae_sent}
		1298	}
		1299
		1300	sub _wait {
		1301	AnyEvent->one_event while !$_[0]{_ae_sent};
		1302	}
		1303
		1304	sub recv {
		1305	$_[0]->_wait;
		1306
		1307	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		1308	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		1309	}
		1310
		1311	sub cb {
		1312	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		1313	$_[0]{_ae_cb}
		1314	}
		1315
		1316	sub begin {
		1317	++$_[0]{_ae_counter};
		1318	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		1319	}
		1320
		1321	sub end {
		1322	return if --$_[0]{_ae_counter};
		1323	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
		1324	}
		1325
		1326	# undocumented/compatibility with pre-3.4
		1327	*broadcast = \&send;
		1328	*wait = \&_wait;
		1329
		1330	=head1 ERROR AND EXCEPTION HANDLING
		1331
		1332	In general, AnyEvent does not do any error handling - it relies on the
		1333	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1334	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1335	checking of all AnyEvent methods, however, which is highly useful during
		1336	development.
		1337
		1338	As for exception handling (i.e. runtime errors and exceptions thrown while
		1339	executing a callback), this is not only highly event-loop specific, but
		1340	also not in any way wrapped by this module, as this is the job of the main
		1341	program.
		1342
		1343	The pure perl event loop simply re-throws the exception (usually
		1344	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1345	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1346	so on.
		1347
		1348	=head1 ENVIRONMENT VARIABLES
		1349
		1350	The following environment variables are used by this module or its
		1351	submodules:
		1352
		1353	=over 4
		1354
		1355	=item C<PERL_ANYEVENT_VERBOSE>
		1356
		1357	By default, AnyEvent will be completely silent except in fatal
		1358	conditions. You can set this environment variable to make AnyEvent more
		1359	talkative.
		1360
		1361	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1362	conditions, such as not being able to load the event model specified by
		1363	C<PERL_ANYEVENT_MODEL>.
		1364
		1365	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1366	model it chooses.
		1367
		1368	=item C<PERL_ANYEVENT_STRICT>
		1369
		1370	AnyEvent does not do much argument checking by default, as thorough
		1371	argument checking is very costly. Setting this variable to a true value
		1372	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1373	check the arguments passed to most method calls. If it finds any problems
		1374	it will croak.
		1375
		1376	In other words, enables "strict" mode.
		1377
		1378	Unlike C<use strict>, it is definitely recommended ot keep it off in
		1379	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1380	developing programs can be very useful, however.
		1381
		1382	=item C<PERL_ANYEVENT_MODEL>
		1383
		1384	This can be used to specify the event model to be used by AnyEvent, before
		1385	auto detection and -probing kicks in. It must be a string consisting
		1386	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1387	and the resulting module name is loaded and if the load was successful,
		1388	used as event model. If it fails to load AnyEvent will proceed with
		1389	auto detection and -probing.
		1390
		1391	This functionality might change in future versions.
		1392
		1393	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1394	could start your program like this:
		1395
		1396	PERL_ANYEVENT_MODEL=Perl perl ...
		1397
		1398	=item C<PERL_ANYEVENT_PROTOCOLS>
		1399
		1400	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1401	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1402	of auto probing).
		1403
		1404	Must be set to a comma-separated list of protocols or address families,
		1405	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1406	used, and preference will be given to protocols mentioned earlier in the
		1407	list.
		1408
		1409	This variable can effectively be used for denial-of-service attacks
		1410	against local programs (e.g. when setuid), although the impact is likely
		1411	small, as the program has to handle conenction and other failures anyways.
		1412
		1413	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1414	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1415	- only support IPv4, never try to resolve or contact IPv6
		1416	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1417	IPv6, but prefer IPv6 over IPv4.
		1418
		1419	=item C<PERL_ANYEVENT_EDNS0>
		1420
		1421	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1422	for DNS. This extension is generally useful to reduce DNS traffic, but
		1423	some (broken) firewalls drop such DNS packets, which is why it is off by
		1424	default.
		1425
		1426	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1427	EDNS0 in its DNS requests.
		1428
		1429	=item C<PERL_ANYEVENT_MAX_FORKS>
		1430
		1431	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1432	will create in parallel.
		1433
		1434	=back
648		1435
649	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1436	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
650		1437
651	This is an advanced topic that you do not normally need to use AnyEvent in	1438	This is an advanced topic that you do not normally need to use AnyEvent in
652	a module. This section is only of use to event loop authors who want to	1439	a module. This section is only of use to event loop authors who want to
…		…
686		1473
687	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1474	I<rxvt-unicode> also cheats a bit by not providing blocking access to
688	condition variables: code blocking while waiting for a condition will	1475	condition variables: code blocking while waiting for a condition will
689	C<die>. This still works with most modules/usages, and blocking calls must	1476	C<die>. This still works with most modules/usages, and blocking calls must
690	not be done in an interactive application, so it makes sense.	1477	not be done in an interactive application, so it makes sense.
691
692	=head1 ENVIRONMENT VARIABLES
693
694	The following environment variables are used by this module:
695
696	=over 4
697
698	=item C<PERL_ANYEVENT_VERBOSE>
699
700	By default, AnyEvent will be completely silent except in fatal
701	conditions. You can set this environment variable to make AnyEvent more
702	talkative.
703
704	When set to C<1> or higher, causes AnyEvent to warn about unexpected
705	conditions, such as not being able to load the event model specified by
706	C<PERL_ANYEVENT_MODEL>.
707
708	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
709	model it chooses.
710
711	=item C<PERL_ANYEVENT_MODEL>
712
713	This can be used to specify the event model to be used by AnyEvent, before
714	autodetection and -probing kicks in. It must be a string consisting
715	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
716	and the resulting module name is loaded and if the load was successful,
717	used as event model. If it fails to load AnyEvent will proceed with
718	autodetection and -probing.
719
720	This functionality might change in future versions.
721
722	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
723	could start your program like this:
724
725	PERL_ANYEVENT_MODEL=Perl perl ...
726
727	=back
728		1478
729	=head1 EXAMPLE PROGRAM	1479	=head1 EXAMPLE PROGRAM
730		1480
731	The following program uses an I/O watcher to read data from STDIN, a timer	1481	The following program uses an I/O watcher to read data from STDIN, a timer
732	to display a message once per second, and a condition variable to quit the	1482	to display a message once per second, and a condition variable to quit the
…		…
741	poll => 'r',	1491	poll => 'r',
742	cb => sub {	1492	cb => sub {
743	warn "io event <$_[0]>\n"; # will always output <r>	1493	warn "io event <$_[0]>\n"; # will always output <r>
744	chomp (my $input = <STDIN>); # read a line	1494	chomp (my $input = <STDIN>); # read a line
745	warn "read: $input\n"; # output what has been read	1495	warn "read: $input\n"; # output what has been read
746	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1496	$cv->send if $input =~ /^q/i; # quit program if /^q/i
747	},	1497	},
748	);	1498	);
749		1499
750	my $time_watcher; # can only be used once	1500	my $time_watcher; # can only be used once
751		1501
…		…
756	});	1506	});
757	}	1507	}
758		1508
759	new_timer; # create first timer	1509	new_timer; # create first timer
760		1510
761	$cv->wait; # wait until user enters /^q/i	1511	$cv->recv; # wait until user enters /^q/i
762		1512
763	=head1 REAL-WORLD EXAMPLE	1513	=head1 REAL-WORLD EXAMPLE
764		1514
765	Consider the L<Net::FCP> module. It features (among others) the following	1515	Consider the L<Net::FCP> module. It features (among others) the following
766	API calls, which are to freenet what HTTP GET requests are to http:	1516	API calls, which are to freenet what HTTP GET requests are to http:
…		…
816	syswrite $txn->{fh}, $txn->{request}	1566	syswrite $txn->{fh}, $txn->{request}
817	or die "connection or write error";	1567	or die "connection or write error";
818	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1568	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
819		1569
820	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1570	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
821	result and signals any possible waiters that the request ahs finished:	1571	result and signals any possible waiters that the request has finished:
822		1572
823	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1573	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
824		1574
825	if (end-of-file or data complete) {	1575	if (end-of-file or data complete) {
826	$txn->{result} = $txn->{buf};	1576	$txn->{result} = $txn->{buf};
827	$txn->{finished}->broadcast;	1577	$txn->{finished}->send;
828	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1578	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
829	}	1579	}
830		1580
831	The C<result> method, finally, just waits for the finished signal (if the	1581	The C<result> method, finally, just waits for the finished signal (if the
832	request was already finished, it doesn't wait, of course, and returns the	1582	request was already finished, it doesn't wait, of course, and returns the
833	data:	1583	data:
834		1584
835	$txn->{finished}->wait;	1585	$txn->{finished}->recv;
836	return $txn->{result};	1586	return $txn->{result};
837		1587
838	The actual code goes further and collects all errors (C<die>s, exceptions)	1588	The actual code goes further and collects all errors (C<die>s, exceptions)
839	that occured during request processing. The C<result> method detects	1589	that occurred during request processing. The C<result> method detects
840	whether an exception as thrown (it is stored inside the $txn object)	1590	whether an exception as thrown (it is stored inside the $txn object)
841	and just throws the exception, which means connection errors and other	1591	and just throws the exception, which means connection errors and other
842	problems get reported tot he code that tries to use the result, not in a	1592	problems get reported tot he code that tries to use the result, not in a
843	random callback.	1593	random callback.
844		1594
…		…
875		1625
876	my $quit = AnyEvent->condvar;	1626	my $quit = AnyEvent->condvar;
877		1627
878	$fcp->txn_client_get ($url)->cb (sub {	1628	$fcp->txn_client_get ($url)->cb (sub {
879	...	1629	...
880	$quit->broadcast;	1630	$quit->send;
881	});	1631	});
882		1632
883	$quit->wait;	1633	$quit->recv;
884		1634
885		1635
886	=head1 BENCHMARK	1636	=head1 BENCHMARKS
887		1637
888	To give you an idea of the performance and overheads that AnyEvent adds	1638	To give you an idea of the performance and overheads that AnyEvent adds
889	over the event loops themselves (and to give you an impression of the	1639	over the event loops themselves and to give you an impression of the speed
890	speed of various event loops), here is a benchmark of various supported	1640	of various event loops I prepared some benchmarks.
891	event models natively and with anyevent. The benchmark creates a lot of	1641
892	timers (with a zero timeout) and I/O watchers (watching STDOUT, a pty, to	1642	=head2 BENCHMARKING ANYEVENT OVERHEAD
		1643
		1644	Here is a benchmark of various supported event models used natively and
		1645	through AnyEvent. The benchmark creates a lot of timers (with a zero
		1646	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
893	become writable, which it is), lets them fire exactly once and destroys	1647	which it is), lets them fire exactly once and destroys them again.
894	them again.
895		1648
896	Rewriting the benchmark to use many different sockets instead of using	1649	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
897	the same filehandle for all I/O watchers results in a much longer runtime	1650	distribution.
898	(socket creation is expensive), but qualitatively the same figures, so it
899	was not used.
900		1651
901	=head2 Explanation of the columns	1652	=head3 Explanation of the columns
902		1653
903	I<watcher> is the number of event watchers created/destroyed. Since	1654	I<watcher> is the number of event watchers created/destroyed. Since
904	different event models feature vastly different performances, each event	1655	different event models feature vastly different performances, each event
905	loop was given a number of watchers so that overall runtime is acceptable	1656	loop was given a number of watchers so that overall runtime is acceptable
906	and similar between tested event loop (and keep them from crashing): Glib	1657	and similar between tested event loop (and keep them from crashing): Glib
…		…
916	all watchers, to avoid adding memory overhead. That means closure creation	1667	all watchers, to avoid adding memory overhead. That means closure creation
917	and memory usage is not included in the figures.	1668	and memory usage is not included in the figures.
918		1669
919	I<invoke> is the time, in microseconds, used to invoke a simple	1670	I<invoke> is the time, in microseconds, used to invoke a simple
920	callback. The callback simply counts down a Perl variable and after it was	1671	callback. The callback simply counts down a Perl variable and after it was
921	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1672	invoked "watcher" times, it would C<< ->send >> a condvar once to
922	signal the end of this phase.	1673	signal the end of this phase.
923		1674
924	I<destroy> is the time, in microseconds, that it takes to destroy a single	1675	I<destroy> is the time, in microseconds, that it takes to destroy a single
925	watcher.	1676	watcher.
926		1677
927	=head2 Results	1678	=head3 Results
928		1679
929	name watchers bytes create invoke destroy comment	1680	name watchers bytes create invoke destroy comment
930	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1681	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
931	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1682	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
932	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1683	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
933	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1684	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
934	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1685	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
935	Event/Any 16000 936 39.17 33.63 1.43 Event + AnyEvent watchers	1686	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
936	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1687	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
937	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1688	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
938	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1689	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
939	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1690	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
940		1691
941	=head2 Discussion	1692	=head3 Discussion
942		1693
943	The benchmark does I<not> measure scalability of the event loop very	1694	The benchmark does I<not> measure scalability of the event loop very
944	well. For example, a select-based event loop (such as the pure perl one)	1695	well. For example, a select-based event loop (such as the pure perl one)
945	can never compete with an event loop that uses epoll when the number of	1696	can never compete with an event loop that uses epoll when the number of
946	file descriptors grows high. In this benchmark, all events become ready at	1697	file descriptors grows high. In this benchmark, all events become ready at
947	the same time, so select/poll-based implementations get an unnatural speed	1698	the same time, so select/poll-based implementations get an unnatural speed
948	boost.	1699	boost.
949		1700
		1701	Also, note that the number of watchers usually has a nonlinear effect on
		1702	overall speed, that is, creating twice as many watchers doesn't take twice
		1703	the time - usually it takes longer. This puts event loops tested with a
		1704	higher number of watchers at a disadvantage.
		1705
		1706	To put the range of results into perspective, consider that on the
		1707	benchmark machine, handling an event takes roughly 1600 CPU cycles with
		1708	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
		1709	cycles with POE.
		1710
950	C<EV> is the sole leader regarding speed and memory use, which are both	1711	C<EV> is the sole leader regarding speed and memory use, which are both
951	maximal/minimal, respectively. Even when going through AnyEvent, there are	1712	maximal/minimal, respectively. Even when going through AnyEvent, it uses
952	only two event loops that use slightly less memory (the C<Event> module	1713	far less memory than any other event loop and is still faster than Event
953	natively and the pure perl backend), and no faster event models, not even	1714	natively.
954	C<Event> natively.
955		1715
956	The pure perl implementation is hit in a few sweet spots (both the	1716	The pure perl implementation is hit in a few sweet spots (both the
957	zero timeout and the use of a single fd hit optimisations in the perl	1717	constant timeout and the use of a single fd hit optimisations in the perl
958	interpreter and the backend itself, and all watchers become ready at the	1718	interpreter and the backend itself). Nevertheless this shows that it
959	same time). Nevertheless this shows that it adds very little overhead in	1719	adds very little overhead in itself. Like any select-based backend its
960	itself. Like any select-based backend its performance becomes really bad	1720	performance becomes really bad with lots of file descriptors (and few of
961	with lots of file descriptors (and few of them active), of course, but	1721	them active), of course, but this was not subject of this benchmark.
962	this was not subject of this benchmark.
963		1722
964	The C<Event> module has a relatively high setup and callback invocation cost,	1723	The C<Event> module has a relatively high setup and callback invocation
965	but overall scores on the third place.	1724	cost, but overall scores in on the third place.
966		1725
967	C<Glib>'s memory usage is quite a bit bit higher, but it features a	1726	C<Glib>'s memory usage is quite a bit higher, but it features a
968	faster callback invocation and overall ends up in the same class as	1727	faster callback invocation and overall ends up in the same class as
969	C<Event>. However, Glib scales extremely badly, doubling the number of	1728	C<Event>. However, Glib scales extremely badly, doubling the number of
970	watchers increases the processing time by more than a factor of four,	1729	watchers increases the processing time by more than a factor of four,
971	making it completely unusable when using larger numbers of watchers	1730	making it completely unusable when using larger numbers of watchers
972	(note that only a single file descriptor was used in the benchmark, so	1731	(note that only a single file descriptor was used in the benchmark, so
…		…
975	The C<Tk> adaptor works relatively well. The fact that it crashes with	1734	The C<Tk> adaptor works relatively well. The fact that it crashes with
976	more than 2000 watchers is a big setback, however, as correctness takes	1735	more than 2000 watchers is a big setback, however, as correctness takes
977	precedence over speed. Nevertheless, its performance is surprising, as the	1736	precedence over speed. Nevertheless, its performance is surprising, as the
978	file descriptor is dup()ed for each watcher. This shows that the dup()	1737	file descriptor is dup()ed for each watcher. This shows that the dup()
979	employed by some adaptors is not a big performance issue (it does incur a	1738	employed by some adaptors is not a big performance issue (it does incur a
980	hidden memory cost inside the kernel, though, that is not reflected in the	1739	hidden memory cost inside the kernel which is not reflected in the figures
981	figures above).	1740	above).
982		1741
983	C<POE>, regardless of underlying event loop (wether using its pure perl	1742	C<POE>, regardless of underlying event loop (whether using its pure perl
984	select-based backend or the Event module) shows abysmal performance and	1743	select-based backend or the Event module, the POE-EV backend couldn't
		1744	be tested because it wasn't working) shows abysmal performance and
985	memory usage: Watchers use almost 30 times as much memory as EV watchers,	1745	memory usage with AnyEvent: Watchers use almost 30 times as much memory
986	and 10 times as much memory as both Event or EV via AnyEvent. Watcher	1746	as EV watchers, and 10 times as much memory as Event (the high memory
		1747	requirements are caused by requiring a session for each watcher). Watcher
987	invocation is almost 900 times slower than with AnyEvent's pure perl	1748	invocation speed is almost 900 times slower than with AnyEvent's pure perl
		1749	implementation.
		1750
988	implementation. The design of the POE adaptor class in AnyEvent can not	1751	The design of the POE adaptor class in AnyEvent can not really account
989	really account for this, as session creation overhead is small compared	1752	for the performance issues, though, as session creation overhead is
990	to execution of the state machine, which is coded pretty optimally within	1753	small compared to execution of the state machine, which is coded pretty
991	L<AnyEvent::Impl::POE>. POE simply seems to be abysmally slow.	1754	optimally within L<AnyEvent::Impl::POE> (and while everybody agrees that
		1755	using multiple sessions is not a good approach, especially regarding
		1756	memory usage, even the author of POE could not come up with a faster
		1757	design).
992		1758
993	=head2 Summary	1759	=head3 Summary
994		1760
		1761	=over 4
		1762
995	Using EV through AnyEvent is faster than any other event loop, but most	1763	=item * Using EV through AnyEvent is faster than any other event loop
996	event loops have acceptable performance with or without AnyEvent.	1764	(even when used without AnyEvent), but most event loops have acceptable
		1765	performance with or without AnyEvent.
997		1766
998	The overhead AnyEvent adds is usually much smaller than the overhead of	1767	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
999	the actual event loop, only with extremely fast event loops such as the EV	1768	the actual event loop, only with extremely fast event loops such as EV
1000	adds AnyEvent significant overhead.	1769	adds AnyEvent significant overhead.
1001		1770
1002	And you should simply avoid POE like the plague if you want performance or	1771	=item * You should avoid POE like the plague if you want performance or
1003	reasonable memory usage.	1772	reasonable memory usage.
1004		1773
		1774	=back
		1775
		1776	=head2 BENCHMARKING THE LARGE SERVER CASE
		1777
		1778	This benchmark actually benchmarks the event loop itself. It works by
		1779	creating a number of "servers": each server consists of a socket pair, a
		1780	timeout watcher that gets reset on activity (but never fires), and an I/O
		1781	watcher waiting for input on one side of the socket. Each time the socket
		1782	watcher reads a byte it will write that byte to a random other "server".
		1783
		1784	The effect is that there will be a lot of I/O watchers, only part of which
		1785	are active at any one point (so there is a constant number of active
		1786	fds for each loop iteration, but which fds these are is random). The
		1787	timeout is reset each time something is read because that reflects how
		1788	most timeouts work (and puts extra pressure on the event loops).
		1789
		1790	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
		1791	(1%) are active. This mirrors the activity of large servers with many
		1792	connections, most of which are idle at any one point in time.
		1793
		1794	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
		1795	distribution.
		1796
		1797	=head3 Explanation of the columns
		1798
		1799	I<sockets> is the number of sockets, and twice the number of "servers" (as
		1800	each server has a read and write socket end).
		1801
		1802	I<create> is the time it takes to create a socket pair (which is
		1803	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
		1804
		1805	I<request>, the most important value, is the time it takes to handle a
		1806	single "request", that is, reading the token from the pipe and forwarding
		1807	it to another server. This includes deleting the old timeout and creating
		1808	a new one that moves the timeout into the future.
		1809
		1810	=head3 Results
		1811
		1812	name sockets create request
		1813	EV 20000 69.01 11.16
		1814	Perl 20000 73.32 35.87
		1815	Event 20000 212.62 257.32
		1816	Glib 20000 651.16 1896.30
		1817	POE 20000 349.67 12317.24 uses POE::Loop::Event
		1818
		1819	=head3 Discussion
		1820
		1821	This benchmark I<does> measure scalability and overall performance of the
		1822	particular event loop.
		1823
		1824	EV is again fastest. Since it is using epoll on my system, the setup time
		1825	is relatively high, though.
		1826
		1827	Perl surprisingly comes second. It is much faster than the C-based event
		1828	loops Event and Glib.
		1829
		1830	Event suffers from high setup time as well (look at its code and you will
		1831	understand why). Callback invocation also has a high overhead compared to
		1832	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
		1833	uses select or poll in basically all documented configurations.
		1834
		1835	Glib is hit hard by its quadratic behaviour w.r.t. many watchers. It
		1836	clearly fails to perform with many filehandles or in busy servers.
		1837
		1838	POE is still completely out of the picture, taking over 1000 times as long
		1839	as EV, and over 100 times as long as the Perl implementation, even though
		1840	it uses a C-based event loop in this case.
		1841
		1842	=head3 Summary
		1843
		1844	=over 4
		1845
		1846	=item * The pure perl implementation performs extremely well.
		1847
		1848	=item * Avoid Glib or POE in large projects where performance matters.
		1849
		1850	=back
		1851
		1852	=head2 BENCHMARKING SMALL SERVERS
		1853
		1854	While event loops should scale (and select-based ones do not...) even to
		1855	large servers, most programs we (or I :) actually write have only a few
		1856	I/O watchers.
		1857
		1858	In this benchmark, I use the same benchmark program as in the large server
		1859	case, but it uses only eight "servers", of which three are active at any
		1860	one time. This should reflect performance for a small server relatively
		1861	well.
		1862
		1863	The columns are identical to the previous table.
		1864
		1865	=head3 Results
		1866
		1867	name sockets create request
		1868	EV 16 20.00 6.54
		1869	Perl 16 25.75 12.62
		1870	Event 16 81.27 35.86
		1871	Glib 16 32.63 15.48
		1872	POE 16 261.87 276.28 uses POE::Loop::Event
		1873
		1874	=head3 Discussion
		1875
		1876	The benchmark tries to test the performance of a typical small
		1877	server. While knowing how various event loops perform is interesting, keep
		1878	in mind that their overhead in this case is usually not as important, due
		1879	to the small absolute number of watchers (that is, you need efficiency and
		1880	speed most when you have lots of watchers, not when you only have a few of
		1881	them).
		1882
		1883	EV is again fastest.
		1884
		1885	Perl again comes second. It is noticeably faster than the C-based event
		1886	loops Event and Glib, although the difference is too small to really
		1887	matter.
		1888
		1889	POE also performs much better in this case, but is is still far behind the
		1890	others.
		1891
		1892	=head3 Summary
		1893
		1894	=over 4
		1895
		1896	=item * C-based event loops perform very well with small number of
		1897	watchers, as the management overhead dominates.
		1898
		1899	=back
		1900
		1901
		1902	=head1 SIGNALS
		1903
		1904	AnyEvent currently installs handlers for these signals:
		1905
		1906	=over 4
		1907
		1908	=item SIGCHLD
		1909
		1910	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		1911	emulation for event loops that do not support them natively. Also, some
		1912	event loops install a similar handler.
		1913
		1914	=item SIGPIPE
		1915
		1916	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		1917	when AnyEvent gets loaded.
		1918
		1919	The rationale for this is that AnyEvent users usually do not really depend
		1920	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		1921	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		1922	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		1923	some random socket.
		1924
		1925	The rationale for installing a no-op handler as opposed to ignoring it is
		1926	that this way, the handler will be restored to defaults on exec.
		1927
		1928	Feel free to install your own handler, or reset it to defaults.
		1929
		1930	=back
		1931
		1932	=cut
		1933
		1934	$SIG{PIPE} = sub { }
		1935	unless defined $SIG{PIPE};
		1936
1005		1937
1006	=head1 FORK	1938	=head1 FORK
1007		1939
1008	Most event libraries are not fork-safe. The ones who are usually are	1940	Most event libraries are not fork-safe. The ones who are usually are
1009	because they are so inefficient. Only L<EV> is fully fork-aware.	1941	because they rely on inefficient but fork-safe C<select> or C<poll>
		1942	calls. Only L<EV> is fully fork-aware.
1010		1943
1011	If you have to fork, you must either do so I<before> creating your first	1944	If you have to fork, you must either do so I<before> creating your first
1012	watcher OR you must not use AnyEvent at all in the child.	1945	watcher OR you must not use AnyEvent at all in the child.
1013		1946
1014		1947
…		…
1022	specified in the variable.	1955	specified in the variable.
1023		1956
1024	You can make AnyEvent completely ignore this variable by deleting it	1957	You can make AnyEvent completely ignore this variable by deleting it
1025	before the first watcher gets created, e.g. with a C<BEGIN> block:	1958	before the first watcher gets created, e.g. with a C<BEGIN> block:
1026		1959
1027	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1960	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1028		1961
1029	use AnyEvent;	1962	use AnyEvent;
		1963
		1964	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
		1965	be used to probe what backend is used and gain other information (which is
		1966	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1967	$ENV{PERL_ANYEGENT_STRICT}.
		1968
		1969
		1970	=head1 BUGS
		1971
		1972	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		1973	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		1974	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		1975	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
		1976	pronounced).
1030		1977
1031		1978
1032	=head1 SEE ALSO	1979	=head1 SEE ALSO
1033		1980
1034	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,	1981	Utility functions: L<AnyEvent::Util>.
1035	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,	1982
		1983	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1036	L<Event::Lib>, L<Qt>, L<POE>.	1984	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1037		1985
1038	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,	1986	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1039	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,	1987	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1040	L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>,	1988	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1041	L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>.	1989	L<AnyEvent::Impl::POE>.
1042		1990
		1991	Non-blocking file handles, sockets, TCP clients and
		1992	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1993
		1994	Asynchronous DNS: L<AnyEvent::DNS>.
		1995
		1996	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
		1997
1043	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1998	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1044		1999
1045		2000
1046	=head1 AUTHOR	2001	=head1 AUTHOR
1047		2002
1048	Marc Lehmann <schmorp@schmorp.de>	2003	Marc Lehmann <schmorp@schmorp.de>
1049	http://home.schmorp.de/	2004	http://home.schmorp.de/
1050		2005
1051	=cut	2006	=cut
1052		2007
1053	1	2008	1
1054		2009

Diff Legend

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