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Revision 1.376 by root, Thu Aug 25 06:34:11 2011 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt,
		6	FLTK and POE are various supported event loops/environments.
6		7
7	=head1 SYNOPSIS	8	=head1 SYNOPSIS
8		9
9	use AnyEvent;	10	use AnyEvent;
10		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
		15	# file handle or descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
12		17
		18	# one-shot or repeating timers
13	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
14	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
15		21
16	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
17	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
18		24
		25	# POSIX signal
19	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });	26	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
20		27
		28	# child process exit
21	my $w = AnyEvent->child (pid => $pid, cb => sub {	29	my $w = AnyEvent->child (pid => $pid, cb => sub {
22	my ($pid, $status) = @_;	30	my ($pid, $status) = @_;
23	...	31	...
24	});	32	});
		33
		34	# called when event loop idle (if applicable)
		35	my $w = AnyEvent->idle (cb => sub { ... });
25		36
26	my $w = AnyEvent->condvar; # stores whether a condition was flagged	37	my $w = AnyEvent->condvar; # stores whether a condition was flagged
27	$w->send; # wake up current and all future recv's	38	$w->send; # wake up current and all future recv's
28	$w->recv; # enters "main loop" till $condvar gets ->send	39	$w->recv; # enters "main loop" till $condvar gets ->send
29	# use a condvar in callback mode:	40	# use a condvar in callback mode:
…		…
32	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
33		44
34	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
35	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
36	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
		48
		49	=head1 SUPPORT
		50
		51	An FAQ document is available as L<AnyEvent::FAQ>.
		52
		53	There also is a mailinglist for discussing all things AnyEvent, and an IRC
		54	channel, too.
		55
		56	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		57	Repository>, at L<http://anyevent.schmorp.de>, for more info.
37		58
38	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	59	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
39		60
40	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	61	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
41	nowadays. So what is different about AnyEvent?	62	nowadays. So what is different about AnyEvent?
…		…
57	module users into the same thing by forcing them to use the same event	78	module users into the same thing by forcing them to use the same event
58	model you use.	79	model you use.
59		80
60	For modules like POE or IO::Async (which is a total misnomer as it is	81	For modules like POE or IO::Async (which is a total misnomer as it is
61	actually doing all I/O I<synchronously>...), using them in your module is	82	actually doing all I/O I<synchronously>...), using them in your module is
62	like joining a cult: After you joined, you are dependent on them and you	83	like joining a cult: After you join, you are dependent on them and you
63	cannot use anything else, as they are simply incompatible to everything	84	cannot use anything else, as they are simply incompatible to everything
64	that isn't them. What's worse, all the potential users of your	85	that isn't them. What's worse, all the potential users of your
65	module are I<also> forced to use the same event loop you use.	86	module are I<also> forced to use the same event loop you use.
66		87
67	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	88	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
68	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	89	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
69	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if	90	with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module
70	your module uses one of those, every user of your module has to use it,	91	uses one of those, every user of your module has to use it, too. But if
71	too. But if your module uses AnyEvent, it works transparently with all	92	your module uses AnyEvent, it works transparently with all event models it
72	event models it supports (including stuff like IO::Async, as long as those	93	supports (including stuff like IO::Async, as long as those use one of the
73	use one of the supported event loops. It is trivial to add new event loops	94	supported event loops. It is easy to add new event loops to AnyEvent, too,
74	to AnyEvent, too, so it is future-proof).	95	so it is future-proof).
75		96
76	In addition to being free of having to use I<the one and only true event	97	In addition to being free of having to use I<the one and only true event
77	model>, AnyEvent also is free of bloat and policy: with POE or similar	98	model>, AnyEvent also is free of bloat and policy: with POE or similar
78	modules, you get an enormous amount of code and strict rules you have to	99	modules, you get an enormous amount of code and strict rules you have to
79	follow. AnyEvent, on the other hand, is lean and up to the point, by only	100	follow. AnyEvent, on the other hand, is lean and to the point, by only
80	offering the functionality that is necessary, in as thin as a wrapper as	101	offering the functionality that is necessary, in as thin as a wrapper as
81	technically possible.	102	technically possible.
82		103
83	Of course, AnyEvent comes with a big (and fully optional!) toolbox	104	Of course, AnyEvent comes with a big (and fully optional!) toolbox
84	of useful functionality, such as an asynchronous DNS resolver, 100%	105	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
90	useful) and you want to force your users to use the one and only event	111	useful) and you want to force your users to use the one and only event
91	model, you should I<not> use this module.	112	model, you should I<not> use this module.
92		113
93	=head1 DESCRIPTION	114	=head1 DESCRIPTION
94		115
95	L<AnyEvent> provides an identical interface to multiple event loops. This	116	L<AnyEvent> provides a uniform interface to various event loops. This
96	allows module authors to utilise an event loop without forcing module	117	allows module authors to use event loop functionality without forcing
97	users to use the same event loop (as only a single event loop can coexist	118	module users to use a specific event loop implementation (since more
98	peacefully at any one time).	119	than one event loop cannot coexist peacefully).
99		120
100	The interface itself is vaguely similar, but not identical to the L<Event>	121	The interface itself is vaguely similar, but not identical to the L<Event>
101	module.	122	module.
102		123
103	During the first call of any watcher-creation method, the module tries	124	During the first call of any watcher-creation method, the module tries
104	to detect the currently loaded event loop by probing whether one of the	125	to detect the currently loaded event loop by probing whether one of the
105	following modules is already loaded: L<EV>,	126	following modules is already loaded: L<EV>, L<AnyEvent::Loop>,
106	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	127	L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one
107	L<POE>. The first one found is used. If none are found, the module tries	128	found is used. If none are detected, the module tries to load the first
108	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	129	four modules in the order given; but note that if L<EV> is not
109	adaptor should always succeed) in the order given. The first one that can	130	available, the pure-perl L<AnyEvent::Loop> should always work, so
110	be successfully loaded will be used. If, after this, still none could be	131	the other two are not normally tried.
111	found, AnyEvent will fall back to a pure-perl event loop, which is not
112	very efficient, but should work everywhere.
113		132
114	Because AnyEvent first checks for modules that are already loaded, loading	133	Because AnyEvent first checks for modules that are already loaded, loading
115	an event model explicitly before first using AnyEvent will likely make	134	an event model explicitly before first using AnyEvent will likely make
116	that model the default. For example:	135	that model the default. For example:
117		136
…		…
119	use AnyEvent;	138	use AnyEvent;
120		139
121	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
122		141
123	The I<likely> means that, if any module loads another event model and	142	The I<likely> means that, if any module loads another event model and
124	starts using it, all bets are off. Maybe you should tell their authors to	143	starts using it, all bets are off - this case should be very rare though,
125	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
126		146
127	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called C<AnyEvent::Loop>. Like
128	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	148	other event modules you can load it explicitly and enjoy the high
129	explicitly and enjoy the high availability of that event loop :)	149	availability of that event loop :)
130		150
131	=head1 WATCHERS	151	=head1 WATCHERS
132		152
133	AnyEvent has the central concept of a I<watcher>, which is an object that	153	AnyEvent has the central concept of a I<watcher>, which is an object that
134	stores relevant data for each kind of event you are waiting for, such as	154	stores relevant data for each kind of event you are waiting for, such as
…		…
139	callback when the event occurs (of course, only when the event model	159	callback when the event occurs (of course, only when the event model
140	is in control).	160	is in control).
141		161
142	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
143	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<	163	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
144	callbacks must not C<die> >>. The former is good programming practise in	164	callbacks must not C<die> >>. The former is good programming practice in
145	Perl and the latter stems from the fact that exception handling differs	165	Perl and the latter stems from the fact that exception handling differs
146	widely between event loops.	166	widely between event loops.
147		167
148	To disable the watcher you have to destroy it (e.g. by setting the	168	To disable a watcher you have to destroy it (e.g. by setting the
149	variable you store it in to C<undef> or otherwise deleting all references	169	variable you store it in to C<undef> or otherwise deleting all references
150	to it).	170	to it).
151		171
152	All watchers are created by calling a method on the C<AnyEvent> class.	172	All watchers are created by calling a method on the C<AnyEvent> class.
153		173
154	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
155	example), or need to refer to their watcher object in other ways.	175	example), or need to refer to their watcher object in other ways.
156		176
157	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
158		178
159	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
160	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
161	undef $w;	181	undef $w;
162	});	182	});
…		…
165	my variables are only visible after the statement in which they are	185	my variables are only visible after the statement in which they are
166	declared.	186	declared.
167		187
168	=head2 I/O WATCHERS	188	=head2 I/O WATCHERS
169		189
		190	$w = AnyEvent->io (
		191	fh => <filehandle_or_fileno>,
		192	poll => <"r" or "w">,
		193	cb => <callback>,
		194	);
		195
170	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	196	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
171	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
172		198
173	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events	199	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
174	(AnyEvent might or might not keep a reference to this file handle). C<poll>	200	for events (AnyEvent might or might not keep a reference to this file
		201	handle). Note that only file handles pointing to things for which
		202	non-blocking operation makes sense are allowed. This includes sockets,
		203	most character devices, pipes, fifos and so on, but not for example files
		204	or block devices.
		205
175	must be a string that is either C<r> or C<w>, which creates a watcher	206	C<poll> must be a string that is either C<r> or C<w>, which creates a
176	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the	207	watcher waiting for "r"eadable or "w"ritable events, respectively.
		208
177	callback to invoke each time the file handle becomes ready.	209	C<cb> is the callback to invoke each time the file handle becomes ready.
178		210
179	Although the callback might get passed parameters, their value and	211	Although the callback might get passed parameters, their value and
180	presence is undefined and you cannot rely on them. Portable AnyEvent	212	presence is undefined and you cannot rely on them. Portable AnyEvent
181	callbacks cannot use arguments passed to I/O watcher callbacks.	213	callbacks cannot use arguments passed to I/O watcher callbacks.
182		214
183	The I/O watcher might use the underlying file descriptor or a copy of it.	215	The I/O watcher might use the underlying file descriptor or a copy of it.
184	You must not close a file handle as long as any watcher is active on the	216	You must not close a file handle as long as any watcher is active on the
185	underlying file descriptor.	217	underlying file descriptor.
186		218
187	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
188	always use non-blocking calls when reading/writing from/to your file	220	always use non-blocking calls when reading/writing from/to your file
189	handles.	221	handles.
190		222
191	Example: wait for readability of STDIN, then read a line and disable the	223	Example: wait for readability of STDIN, then read a line and disable the
192	watcher.	224	watcher.
…		…
197	undef $w;	229	undef $w;
198	});	230	});
199		231
200	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
201		233
		234	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		235
		236	$w = AnyEvent->timer (
		237	after => <fractional_seconds>,
		238	interval => <fractional_seconds>,
		239	cb => <callback>,
		240	);
		241
202	You can create a time watcher by calling the C<< AnyEvent->timer >>	242	You can create a time watcher by calling the C<< AnyEvent->timer >>
203	method with the following mandatory arguments:	243	method with the following mandatory arguments:
204		244
205	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
206	supported) the callback should be invoked. C<cb> is the callback to invoke	246	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
208		248
209	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
210	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
211	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
212		252
213	The callback will normally be invoked once only. If you specify another	253	The callback will normally be invoked only once. If you specify another
214	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
215	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
216	seconds) after the first invocation. If C<interval> is specified with a	256	seconds) after the first invocation. If C<interval> is specified with a
217	false value, then it is treated as if it were missing.	257	false value, then it is treated as if it were not specified at all.
218		258
219	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
220	attempt is done to avoid timer drift in most backends, so the interval is	260	attempt is made to avoid timer drift in most backends, so the interval is
221	only approximate.	261	only approximate.
222		262
223	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
224		264
225	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
243		283
244	While most event loops expect timers to specified in a relative way, they	284	While most event loops expect timers to specified in a relative way, they
245	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
246	"jumps", for example, when ntp decides to set your clock backwards from	286	"jumps", for example, when ntp decides to set your clock backwards from
247	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to	287	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to
248	fire "after" a second might actually take six years to finally fire.	288	fire "after a second" might actually take six years to finally fire.
249		289
250	AnyEvent cannot compensate for this. The only event loop that is conscious	290	AnyEvent cannot compensate for this. The only event loop that is conscious
251	about these issues is L<EV>, which offers both relative (ev_timer, based	291	of these issues is L<EV>, which offers both relative (ev_timer, based
252	on true relative time) and absolute (ev_periodic, based on wallclock time)	292	on true relative time) and absolute (ev_periodic, based on wallclock time)
253	timers.	293	timers.
254		294
255	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
256	AnyEvent API.	296	AnyEvent API.
…		…
278	I<In almost all cases (in all cases if you don't care), this is the	318	I<In almost all cases (in all cases if you don't care), this is the
279	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
280		320
281	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
282	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
283	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
284		324
285	The rest of this section is only of relevance if you try to be very exact	325	The rest of this section is only of relevance if you try to be very exact
286	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
287		327
288	For a practical example of when these times differ, consider L<Event::Lib>	328	For a practical example of when these times differ, consider L<Event::Lib>
289	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
290		330
291	The event loop is running and has just invoked one of your callback at	331	The event loop is running and has just invoked one of your callbacks at
292	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
293	you wait a second by executing C<sleep 1> (blocking the process for a	333	you wait a second by executing C<sleep 1> (blocking the process for a
294	second) and then (at time=501) you create a relative timer that fires	334	second) and then (at time=501) you create a relative timer that fires
295	after three seconds.	335	after three seconds.
296		336
…		…
314	In either case, if you care (and in most cases, you don't), then you	354	In either case, if you care (and in most cases, you don't), then you
315	can get whatever behaviour you want with any event loop, by taking the	355	can get whatever behaviour you want with any event loop, by taking the
316	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	356	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
317	account.	357	account.
318		358
		359	=item AnyEvent->now_update
		360
		361	Some event loops (such as L<EV> or L<AnyEvent::Loop>) cache the current
		362	time for each loop iteration (see the discussion of L<< AnyEvent->now >>,
		363	above).
		364
		365	When a callback runs for a long time (or when the process sleeps), then
		366	this "current" time will differ substantially from the real time, which
		367	might affect timers and time-outs.
		368
		369	When this is the case, you can call this method, which will update the
		370	event loop's idea of "current time".
		371
		372	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		373	when mod_perl executes the script, then the event loop will have the wrong
		374	idea about the "current time" (being potentially far in the past, when the
		375	script ran the last time). In that case you should arrange a call to C<<
		376	AnyEvent->now_update >> each time the web server process wakes up again
		377	(e.g. at the start of your script, or in a handler).
		378
		379	Note that updating the time I<might> cause some events to be handled.
		380
319	=back	381	=back
320		382
321	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
322		386
323	You can watch for signals using a signal watcher, C<signal> is the signal	387	You can watch for signals using a signal watcher, C<signal> is the signal
324	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	388	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
325	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
326		390
…		…
332	invocation, and callback invocation will be synchronous. Synchronous means	396	invocation, and callback invocation will be synchronous. Synchronous means
333	that it might take a while until the signal gets handled by the process,	397	that it might take a while until the signal gets handled by the process,
334	but it is guaranteed not to interrupt any other callbacks.	398	but it is guaranteed not to interrupt any other callbacks.
335		399
336	The main advantage of using these watchers is that you can share a signal	400	The main advantage of using these watchers is that you can share a signal
337	between multiple watchers.	401	between multiple watchers, and AnyEvent will ensure that signals will not
		402	interrupt your program at bad times.
338		403
339	This watcher might use C<%SIG>, so programs overwriting those signals	404	This watcher might use C<%SIG> (depending on the event loop used),
340	directly will likely not work correctly.	405	so programs overwriting those signals directly will likely not work
		406	correctly.
341		407
342	Example: exit on SIGINT	408	Example: exit on SIGINT
343		409
344	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
345		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling) or
		421	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		422	latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
		429	=head3 Signal Races, Delays and Workarounds
		430
		431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		432	callbacks to signals in a generic way, which is a pity, as you cannot
		433	do race-free signal handling in perl, requiring C libraries for
		434	this. AnyEvent will try to do its best, which means in some cases,
		435	signals will be delayed. The maximum time a signal might be delayed is
		436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		437	variable can be changed only before the first signal watcher is created,
		438	and should be left alone otherwise. This variable determines how often
		439	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		440	will cause fewer spurious wake-ups, which is better for power and CPU
		441	saving.
		442
		443	All these problems can be avoided by installing the optional
		444	L<Async::Interrupt> module, which works with most event loops. It will not
		445	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		446	(and not with L<POE> currently, as POE does its own workaround with
		447	one-second latency). For those, you just have to suffer the delays.
		448
346	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
347		450
		451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		452
348	You can also watch on a child process exit and catch its exit status.	453	You can also watch for a child process exit and catch its exit status.
349		454
350	The child process is specified by the C<pid> argument (if set to C<0>, it	455	The child process is specified by the C<pid> argument (on some backends,
351	watches for any child process exit). The watcher will triggered only when	456	using C<0> watches for any child process exit, on others this will
352	the child process has finished and an exit status is available, not on	457	croak). The watcher will be triggered only when the child process has
353	any trace events (stopped/continued).	458	finished and an exit status is available, not on any trace events
		459	(stopped/continued).
354		460
355	The callback will be called with the pid and exit status (as returned by	461	The callback will be called with the pid and exit status (as returned by
356	waitpid), so unlike other watcher types, you I<can> rely on child watcher	462	waitpid), so unlike other watcher types, you I<can> rely on child watcher
357	callback arguments.	463	callback arguments.
358		464
…		…
363		469
364	There is a slight catch to child watchers, however: you usually start them	470	There is a slight catch to child watchers, however: you usually start them
365	I<after> the child process was created, and this means the process could	471	I<after> the child process was created, and this means the process could
366	have exited already (and no SIGCHLD will be sent anymore).	472	have exited already (and no SIGCHLD will be sent anymore).
367		473
368	Not all event models handle this correctly (POE doesn't), but even for	474	Not all event models handle this correctly (neither POE nor IO::Async do,
		475	see their AnyEvent::Impl manpages for details), but even for event models
369	event models that I<do> handle this correctly, they usually need to be	476	that I<do> handle this correctly, they usually need to be loaded before
370	loaded before the process exits (i.e. before you fork in the first place).	477	the process exits (i.e. before you fork in the first place). AnyEvent's
		478	pure perl event loop handles all cases correctly regardless of when you
		479	start the watcher.
371		480
372	This means you cannot create a child watcher as the very first thing in an	481	This means you cannot create a child watcher as the very first
373	AnyEvent program, you I<have> to create at least one watcher before you	482	thing in an AnyEvent program, you I<have> to create at least one
374	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	483	watcher before you C<fork> the child (alternatively, you can call
		484	C<AnyEvent::detect>).
		485
		486	As most event loops do not support waiting for child events, they will be
		487	emulated by AnyEvent in most cases, in which case the latency and race
		488	problems mentioned in the description of signal watchers apply.
375		489
376	Example: fork a process and wait for it	490	Example: fork a process and wait for it
377		491
378	my $done = AnyEvent->condvar;	492	my $done = AnyEvent->condvar;
379		493
…		…
389	);	503	);
390		504
391	# do something else, then wait for process exit	505	# do something else, then wait for process exit
392	$done->recv;	506	$done->recv;
393		507
		508	=head2 IDLE WATCHERS
		509
		510	$w = AnyEvent->idle (cb => <callback>);
		511
		512	This will repeatedly invoke the callback after the process becomes idle,
		513	until either the watcher is destroyed or new events have been detected.
		514
		515	Idle watchers are useful when there is a need to do something, but it
		516	is not so important (or wise) to do it instantly. The callback will be
		517	invoked only when there is "nothing better to do", which is usually
		518	defined as "all outstanding events have been handled and no new events
		519	have been detected". That means that idle watchers ideally get invoked
		520	when the event loop has just polled for new events but none have been
		521	detected. Instead of blocking to wait for more events, the idle watchers
		522	will be invoked.
		523
		524	Unfortunately, most event loops do not really support idle watchers (only
		525	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		526	will simply call the callback "from time to time".
		527
		528	Example: read lines from STDIN, but only process them when the
		529	program is otherwise idle:
		530
		531	my @lines; # read data
		532	my $idle_w;
		533	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		534	push @lines, scalar <STDIN>;
		535
		536	# start an idle watcher, if not already done
		537	$idle_w ||= AnyEvent->idle (cb => sub {
		538	# handle only one line, when there are lines left
		539	if (my $line = shift @lines) {
		540	print "handled when idle: $line";
		541	} else {
		542	# otherwise disable the idle watcher again
		543	undef $idle_w;
		544	}
		545	});
		546	});
		547
394	=head2 CONDITION VARIABLES	548	=head2 CONDITION VARIABLES
		549
		550	$cv = AnyEvent->condvar;
		551
		552	$cv->send (<list>);
		553	my @res = $cv->recv;
395		554
396	If you are familiar with some event loops you will know that all of them	555	If you are familiar with some event loops you will know that all of them
397	require you to run some blocking "loop", "run" or similar function that	556	require you to run some blocking "loop", "run" or similar function that
398	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
399		558
400	AnyEvent is different, it expects somebody else to run the event loop and	559	AnyEvent is slightly different: it expects somebody else to run the event
401	will only block when necessary (usually when told by the user).	560	loop and will only block when necessary (usually when told by the user).
402		561
403	The instrument to do that is called a "condition variable", so called	562	The tool to do that is called a "condition variable", so called because
404	because they represent a condition that must become true.	563	they represent a condition that must become true.
		564
		565	Now is probably a good time to look at the examples further below.
405		566
406	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
407	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
408
409	C<cb>, which specifies a callback to be called when the condition variable	569	C<cb>, which specifies a callback to be called when the condition variable
410	becomes true, with the condition variable as the first argument (but not	570	becomes true, with the condition variable as the first argument (but not
411	the results).	571	the results).
412		572
413	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
414	by calling the C<send> method (or calling the condition variable as if it	574	by calling the C<send> method (or calling the condition variable as if it
415	were a callback, read about the caveats in the description for the C<<	575	were a callback, read about the caveats in the description for the C<<
416	->send >> method).	576	->send >> method).
417		577
418	Condition variables are similar to callbacks, except that you can	578	Since condition variables are the most complex part of the AnyEvent API, here are
419	optionally wait for them. They can also be called merge points - points	579	some different mental models of what they are - pick the ones you can connect to:
420	in time where multiple outstanding events have been processed. And yet	580
421	another way to call them is transactions - each condition variable can be	581	=over 4
422	used to represent a transaction, which finishes at some point and delivers	582
423	a result.	583	=item * Condition variables are like callbacks - you can call them (and pass them instead
		584	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		585
		586	=item * Condition variables are signals - one side can emit or send them,
		587	the other side can wait for them, or install a handler that is called when
		588	the signal fires.
		589
		590	=item * Condition variables are like "Merge Points" - points in your program
		591	where you merge multiple independent results/control flows into one.
		592
		593	=item * Condition variables represent a transaction - functions that start
		594	some kind of transaction can return them, leaving the caller the choice
		595	between waiting in a blocking fashion, or setting a callback.
		596
		597	=item * Condition variables represent future values, or promises to deliver
		598	some result, long before the result is available.
		599
		600	=back
424		601
425	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
426	for example, if you write a module that does asynchronous http requests,	603	for example, if you write a module that does asynchronous http requests,
427	then a condition variable would be the ideal candidate to signal the	604	then a condition variable would be the ideal candidate to signal the
428	availability of results. The user can either act when the callback is	605	availability of results. The user can either act when the callback is
…		…
441		618
442	Condition variables are represented by hash refs in perl, and the keys	619	Condition variables are represented by hash refs in perl, and the keys
443	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing	620	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
444	easy (it is often useful to build your own transaction class on top of	621	easy (it is often useful to build your own transaction class on top of
445	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call	622	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
446	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
447		624
448	There are two "sides" to a condition variable - the "producer side" which	625	There are two "sides" to a condition variable - the "producer side" which
449	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
450	for the send to occur.	627	for the send to occur.
451		628
452	Example: wait for a timer.	629	Example: wait for a timer.
453		630
454	# wait till the result is ready	631	# condition: "wait till the timer is fired"
455	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
456		633
457	# do something such as adding a timer	634	# create the timer - we could wait for, say
458	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
459	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
460	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
461	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
462	after => 1,	639	after => 1,
463	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
464	);	641	);
465		642
466	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
467	# calls send	644	# calls ->send
468	$result_ready->recv;	645	$timer_fired->recv;
469		646
470	Example: wait for a timer, but take advantage of the fact that	647	Example: wait for a timer, but take advantage of the fact that condition
471	condition variables are also code references.	648	variables are also callable directly.
472		649
473	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
474	my $delay = AnyEvent->timer (after => 5, cb => $done);	651	my $delay = AnyEvent->timer (after => 5, cb => $done);
475	$done->recv;	652	$done->recv;
476		653
…		…
482		659
483	...	660	...
484		661
485	my @info = $couchdb->info->recv;	662	my @info = $couchdb->info->recv;
486		663
487	And this is how you would just ste a callback to be called whenever the	664	And this is how you would just set a callback to be called whenever the
488	results are available:	665	results are available:
489		666
490	$couchdb->info->cb (sub {	667	$couchdb->info->cb (sub {
491	my @info = $_[0]->recv;	668	my @info = $_[0]->recv;
492	});	669	});
…		…
510	immediately from within send.	687	immediately from within send.
511		688
512	Any arguments passed to the C<send> call will be returned by all	689	Any arguments passed to the C<send> call will be returned by all
513	future C<< ->recv >> calls.	690	future C<< ->recv >> calls.
514		691
515	Condition variables are overloaded so one can call them directly	692	Condition variables are overloaded so one can call them directly (as if
516	(as a code reference). Calling them directly is the same as calling	693	they were a code reference). Calling them directly is the same as calling
517	C<send>. Note, however, that many C-based event loops do not handle	694	C<send>.
518	overloading, so as tempting as it may be, passing a condition variable
519	instead of a callback does not work. Both the pure perl and EV loops
520	support overloading, however, as well as all functions that use perl to
521	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
522	example).
523		695
524	=item $cv->croak ($error)	696	=item $cv->croak ($error)
525		697
526	Similar to send, but causes all call's to C<< ->recv >> to invoke	698	Similar to send, but causes all calls to C<< ->recv >> to invoke
527	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
528		700
529	This can be used to signal any errors to the condition variable	701	This can be used to signal any errors to the condition variable
530	user/consumer.	702	user/consumer. Doing it this way instead of calling C<croak> directly
		703	delays the error detection, but has the overwhelming advantage that it
		704	diagnoses the error at the place where the result is expected, and not
		705	deep in some event callback with no connection to the actual code causing
		706	the problem.
531		707
532	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
533		709
534	=item $cv->end	710	=item $cv->end
535
536	These two methods are EXPERIMENTAL and MIGHT CHANGE.
537		711
538	These two methods can be used to combine many transactions/events into	712	These two methods can be used to combine many transactions/events into
539	one. For example, a function that pings many hosts in parallel might want	713	one. For example, a function that pings many hosts in parallel might want
540	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
541		715
542	Every call to C<< ->begin >> will increment a counter, and every call to	716	Every call to C<< ->begin >> will increment a counter, and every call to
543	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	717	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
544	>>, the (last) callback passed to C<begin> will be executed. That callback	718	>>, the (last) callback passed to C<begin> will be executed, passing the
545	is I<supposed> to call C<< ->send >>, but that is not required. If no	719	condvar as first argument. That callback is I<supposed> to call C<< ->send
546	callback was set, C<send> will be called without any arguments.	720	>>, but that is not required. If no group callback was set, C<send> will
		721	be called without any arguments.
547		722
548	Let's clarify this with the ping example:	723	You can think of C<< $cv->send >> giving you an OR condition (one call
		724	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		725	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		726
		727	Let's start with a simple example: you have two I/O watchers (for example,
		728	STDOUT and STDERR for a program), and you want to wait for both streams to
		729	close before activating a condvar:
549		730
550	my $cv = AnyEvent->condvar;	731	my $cv = AnyEvent->condvar;
551		732
		733	$cv->begin; # first watcher
		734	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		735	defined sysread $fh1, my $buf, 4096
		736	or $cv->end;
		737	});
		738
		739	$cv->begin; # second watcher
		740	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		741	defined sysread $fh2, my $buf, 4096
		742	or $cv->end;
		743	});
		744
		745	$cv->recv;
		746
		747	This works because for every event source (EOF on file handle), there is
		748	one call to C<begin>, so the condvar waits for all calls to C<end> before
		749	sending.
		750
		751	The ping example mentioned above is slightly more complicated, as the
		752	there are results to be passwd back, and the number of tasks that are
		753	begun can potentially be zero:
		754
		755	my $cv = AnyEvent->condvar;
		756
552	my %result;	757	my %result;
553	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
554		759
555	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
556	$cv->begin;	761	$cv->begin;
557	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
558	$result{$host} = ...;	763	$result{$host} = ...;
…		…
573	loop, which serves two important purposes: first, it sets the callback	778	loop, which serves two important purposes: first, it sets the callback
574	to be called once the counter reaches C<0>, and second, it ensures that	779	to be called once the counter reaches C<0>, and second, it ensures that
575	C<send> is called even when C<no> hosts are being pinged (the loop	780	C<send> is called even when C<no> hosts are being pinged (the loop
576	doesn't execute once).	781	doesn't execute once).
577		782
578	This is the general pattern when you "fan out" into multiple subrequests:	783	This is the general pattern when you "fan out" into multiple (but
579	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	784	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
580	is called at least once, and then, for each subrequest you start, call	785	the callback and ensure C<end> is called at least once, and then, for each
581	C<begin> and for each subrequest you finish, call C<end>.	786	subrequest you start, call C<begin> and for each subrequest you finish,
		787	call C<end>.
582		788
583	=back	789	=back
584		790
585	=head3 METHODS FOR CONSUMERS	791	=head3 METHODS FOR CONSUMERS
586		792
…		…
590	=over 4	796	=over 4
591		797
592	=item $cv->recv	798	=item $cv->recv
593		799
594	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
595	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
596	normally.	802	normally.
597		803
598	You can only wait once on a condition - additional calls are valid but	804	You can only wait once on a condition - additional calls are valid but
599	will return immediately.	805	will return immediately.
600		806
…		…
602	function will call C<croak>.	808	function will call C<croak>.
603		809
604	In list context, all parameters passed to C<send> will be returned,	810	In list context, all parameters passed to C<send> will be returned,
605	in scalar context only the first one will be returned.	811	in scalar context only the first one will be returned.
606		812
		813	Note that doing a blocking wait in a callback is not supported by any
		814	event loop, that is, recursive invocation of a blocking C<< ->recv
		815	>> is not allowed, and the C<recv> call will C<croak> if such a
		816	condition is detected. This condition can be slightly loosened by using
		817	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		818	any thread that doesn't run the event loop itself.
		819
607	Not all event models support a blocking wait - some die in that case	820	Not all event models support a blocking wait - some die in that case
608	(programs might want to do that to stay interactive), so I<if you are	821	(programs might want to do that to stay interactive), so I<if you are
609	using this from a module, never require a blocking wait>, but let the	822	using this from a module, never require a blocking wait>. Instead, let the
610	caller decide whether the call will block or not (for example, by coupling	823	caller decide whether the call will block or not (for example, by coupling
611	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
612	callbacks so the caller knows that getting the result will not block,	825	callbacks so the caller knows that getting the result will not block,
613	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
614		827
615	Another reason I<never> to C<< ->recv >> in a module is that you cannot
616	sensibly have two C<< ->recv >>'s in parallel, as that would require
617	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
618	can supply.
619
620	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
621	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
622	versions and also integrates coroutines into AnyEvent, making blocking
623	C<< ->recv >> calls perfectly safe as long as they are done from another
624	coroutine (one that doesn't run the event loop).
625
626	You can ensure that C<< -recv >> never blocks by setting a callback and	828	You can ensure that C<< ->recv >> never blocks by setting a callback and
627	only calling C<< ->recv >> from within that callback (or at a later	829	only calling C<< ->recv >> from within that callback (or at a later
628	time). This will work even when the event loop does not support blocking	830	time). This will work even when the event loop does not support blocking
629	waits otherwise.	831	waits otherwise.
630		832
631	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
637		839
638	This is a mutator function that returns the callback set and optionally	840	This is a mutator function that returns the callback set and optionally
639	replaces it before doing so.	841	replaces it before doing so.
640		842
641	The callback will be called when the condition becomes "true", i.e. when	843	The callback will be called when the condition becomes "true", i.e. when
642	C<send> or C<croak> are called, with the only argument being the condition	844	C<send> or C<croak> are called, with the only argument being the
643	variable itself. Calling C<recv> inside the callback or at any later time	845	condition variable itself. If the condition is already true, the
644	is guaranteed not to block.	846	callback is called immediately when it is set. Calling C<recv> inside
		847	the callback or at any later time is guaranteed not to block.
645		848
646	=back	849	=back
647		850
		851	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		852
		853	The available backend classes are (every class has its own manpage):
		854
		855	=over 4
		856
		857	=item Backends that are autoprobed when no other event loop can be found.
		858
		859	EV is the preferred backend when no other event loop seems to be in
		860	use. If EV is not installed, then AnyEvent will fall back to its own
		861	pure-perl implementation, which is available everywhere as it comes with
		862	AnyEvent itself.
		863
		864	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		865	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
		866
		867	=item Backends that are transparently being picked up when they are used.
		868
		869	These will be used if they are already loaded when the first watcher
		870	is created, in which case it is assumed that the application is using
		871	them. This means that AnyEvent will automatically pick the right backend
		872	when the main program loads an event module before anything starts to
		873	create watchers. Nothing special needs to be done by the main program.
		874
		875	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		876	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		877	AnyEvent::Impl::Tk based on Tk, very broken.
		878	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		879	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		880	AnyEvent::Impl::Irssi used when running within irssi.
		881	AnyEvent::Impl::IOAsync based on IO::Async.
		882	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
		883	AnyEvent::Impl::FLTK2 based on FLTK (fltk 2 binding).
		884
		885	=item Backends with special needs.
		886
		887	Qt requires the Qt::Application to be instantiated first, but will
		888	otherwise be picked up automatically. As long as the main program
		889	instantiates the application before any AnyEvent watchers are created,
		890	everything should just work.
		891
		892	AnyEvent::Impl::Qt based on Qt.
		893
		894	=item Event loops that are indirectly supported via other backends.
		895
		896	Some event loops can be supported via other modules:
		897
		898	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		899
		900	B<WxWidgets> has no support for watching file handles. However, you can
		901	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		902	polls 20 times per second, which was considered to be too horrible to even
		903	consider for AnyEvent.
		904
		905	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		906	backend, so it can be supported through POE.
		907
		908	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		909	load L<POE> when detecting them, in the hope that POE will pick them up,
		910	in which case everything will be automatic.
		911
		912	=back
		913
648	=head1 GLOBAL VARIABLES AND FUNCTIONS	914	=head1 GLOBAL VARIABLES AND FUNCTIONS
649		915
		916	These are not normally required to use AnyEvent, but can be useful to
		917	write AnyEvent extension modules.
		918
650	=over 4	919	=over 4
651		920
652	=item $AnyEvent::MODEL	921	=item $AnyEvent::MODEL
653		922
654	Contains C<undef> until the first watcher is being created. Then it	923	Contains C<undef> until the first watcher is being created, before the
		924	backend has been autodetected.
		925
655	contains the event model that is being used, which is the name of the	926	Afterwards it contains the event model that is being used, which is the
656	Perl class implementing the model. This class is usually one of the	927	name of the Perl class implementing the model. This class is usually one
657	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	928	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
658	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	929	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
659		930	will be C<urxvt::anyevent>).
660	The known classes so far are:
661
662	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
663	AnyEvent::Impl::Event based on Event, second best choice.
664	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
665	AnyEvent::Impl::Glib based on Glib, third-best choice.
666	AnyEvent::Impl::Tk based on Tk, very bad choice.
667	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
668	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
669	AnyEvent::Impl::POE based on POE, not generic enough for full support.
670
671	There is no support for WxWidgets, as WxWidgets has no support for
672	watching file handles. However, you can use WxWidgets through the
673	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
674	second, which was considered to be too horrible to even consider for
675	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
676	it's adaptor.
677
678	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
679	autodetecting them.
680		931
681	=item AnyEvent::detect	932	=item AnyEvent::detect
682		933
683	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	934	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
684	if necessary. You should only call this function right before you would	935	if necessary. You should only call this function right before you would
685	have created an AnyEvent watcher anyway, that is, as late as possible at	936	have created an AnyEvent watcher anyway, that is, as late as possible at
686	runtime.	937	runtime, and not e.g. during initialisation of your module.
		938
		939	The effect of calling this function is as if a watcher had been created
		940	(specifically, actions that happen "when the first watcher is created"
		941	happen when calling detetc as well).
		942
		943	If you need to do some initialisation before AnyEvent watchers are
		944	created, use C<post_detect>.
687		945
688	=item $guard = AnyEvent::post_detect { BLOCK }	946	=item $guard = AnyEvent::post_detect { BLOCK }
689		947
690	Arranges for the code block to be executed as soon as the event model is	948	Arranges for the code block to be executed as soon as the event model is
691	autodetected (or immediately if this has already happened).	949	autodetected (or immediately if that has already happened).
		950
		951	The block will be executed I<after> the actual backend has been detected
		952	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		953	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		954	other initialisations - see the sources of L<AnyEvent::Strict> or
		955	L<AnyEvent::AIO> to see how this is used.
		956
		957	The most common usage is to create some global watchers, without forcing
		958	event module detection too early, for example, L<AnyEvent::AIO> creates
		959	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		960	avoid autodetecting the event module at load time.
692		961
693	If called in scalar or list context, then it creates and returns an object	962	If called in scalar or list context, then it creates and returns an object
694	that automatically removes the callback again when it is destroyed. See	963	that automatically removes the callback again when it is destroyed (or
		964	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
695	L<Coro::BDB> for a case where this is useful.	965	a case where this is useful.
		966
		967	Example: Create a watcher for the IO::AIO module and store it in
		968	C<$WATCHER>, but do so only do so after the event loop is initialised.
		969
		970	our WATCHER;
		971
		972	my $guard = AnyEvent::post_detect {
		973	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		974	};
		975
		976	# the ||= is important in case post_detect immediately runs the block,
		977	# as to not clobber the newly-created watcher. assigning both watcher and
		978	# post_detect guard to the same variable has the advantage of users being
		979	# able to just C<undef $WATCHER> if the watcher causes them grief.
		980
		981	$WATCHER ||= $guard;
696		982
697	=item @AnyEvent::post_detect	983	=item @AnyEvent::post_detect
698		984
699	If there are any code references in this array (you can C<push> to it	985	If there are any code references in this array (you can C<push> to it
700	before or after loading AnyEvent), then they will called directly after	986	before or after loading AnyEvent), then they will be called directly
701	the event loop has been chosen.	987	after the event loop has been chosen.
702		988
703	You should check C<$AnyEvent::MODEL> before adding to this array, though:	989	You should check C<$AnyEvent::MODEL> before adding to this array, though:
704	if it contains a true value then the event loop has already been detected,	990	if it is defined then the event loop has already been detected, and the
705	and the array will be ignored.	991	array will be ignored.
706		992
707	Best use C<AnyEvent::post_detect { BLOCK }> instead.	993	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		994	it, as it takes care of these details.
		995
		996	This variable is mainly useful for modules that can do something useful
		997	when AnyEvent is used and thus want to know when it is initialised, but do
		998	not need to even load it by default. This array provides the means to hook
		999	into AnyEvent passively, without loading it.
		1000
		1001	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1002	together, you could put this into Coro (this is the actual code used by
		1003	Coro to accomplish this):
		1004
		1005	if (defined $AnyEvent::MODEL) {
		1006	# AnyEvent already initialised, so load Coro::AnyEvent
		1007	require Coro::AnyEvent;
		1008	} else {
		1009	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1010	# as soon as it is
		1011	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1012	}
		1013
		1014	=item AnyEvent::postpone { BLOCK }
		1015
		1016	Arranges for the block to be executed as soon as possible, but not before
		1017	the call itself returns. In practise, the block will be executed just
		1018	before the event loop polls for new events, or shortly afterwards.
		1019
		1020	This function never returns anything (to make the C<return postpone { ...
		1021	}> idiom more useful.
		1022
		1023	To understand the usefulness of this function, consider a function that
		1024	asynchronously does something for you and returns some transaction
		1025	object or guard to let you cancel the operation. For example,
		1026	C<AnyEvent::Socket::tcp_connect>:
		1027
		1028	# start a conenction attempt unless one is active
		1029	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1030	delete $self->{connect_guard};
		1031	...
		1032	};
		1033
		1034	Imagine that this function could instantly call the callback, for
		1035	example, because it detects an obvious error such as a negative port
		1036	number. Invoking the callback before the function returns causes problems
		1037	however: the callback will be called and will try to delete the guard
		1038	object. But since the function hasn't returned yet, there is nothing to
		1039	delete. When the function eventually returns it will assign the guard
		1040	object to C<< $self->{connect_guard} >>, where it will likely never be
		1041	deleted, so the program thinks it is still trying to connect.
		1042
		1043	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1044	callback directly on error:
		1045
		1046	$cb->(undef), return # signal error to callback, BAD!
		1047	if $some_error_condition;
		1048
		1049	It should use C<postpone>:
		1050
		1051	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1052	if $some_error_condition;
		1053
		1054	=item AnyEvent::log $level, $msg[, @args]
		1055
		1056	Log the given C<$msg> at the given C<$level>.
		1057
		1058	If L<AnyEvent::Log> is not loaded then this function makes a simple test
		1059	to see whether the message will be logged. If the test succeeds it will
		1060	load AnyEvent::Log and call C<AnyEvent::Log::log> - consequently, look at
		1061	the L<AnyEvent::Log> documentation for details.
		1062
		1063	If the test fails it will simply return.
		1064
		1065	If you want to sprinkle loads of logging calls around your code, consider
		1066	creating a logger callback with the C<AnyEvent::Log::logger> function,
		1067	which can reduce typing, codesize and can reduce the logging overhead
		1068	enourmously.
708		1069
709	=back	1070	=back
710		1071
711	=head1 WHAT TO DO IN A MODULE	1072	=head1 WHAT TO DO IN A MODULE
712		1073
…		…
723	because it will stall the whole program, and the whole point of using	1084	because it will stall the whole program, and the whole point of using
724	events is to stay interactive.	1085	events is to stay interactive.
725		1086
726	It is fine, however, to call C<< ->recv >> when the user of your module	1087	It is fine, however, to call C<< ->recv >> when the user of your module
727	requests it (i.e. if you create a http request object ad have a method	1088	requests it (i.e. if you create a http request object ad have a method
728	called C<results> that returns the results, it should call C<< ->recv >>	1089	called C<results> that returns the results, it may call C<< ->recv >>
729	freely, as the user of your module knows what she is doing. always).	1090	freely, as the user of your module knows what she is doing. Always).
730		1091
731	=head1 WHAT TO DO IN THE MAIN PROGRAM	1092	=head1 WHAT TO DO IN THE MAIN PROGRAM
732		1093
733	There will always be a single main program - the only place that should	1094	There will always be a single main program - the only place that should
734	dictate which event model to use.	1095	dictate which event model to use.
735		1096
736	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1097	If the program is not event-based, it need not do anything special, even
737	do anything special (it does not need to be event-based) and let AnyEvent	1098	when it depends on a module that uses an AnyEvent. If the program itself
738	decide which implementation to chose if some module relies on it.	1099	uses AnyEvent, but does not care which event loop is used, all it needs
		1100	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1101	available loop implementation.
739		1102
740	If the main program relies on a specific event model - for example, in	1103	If the main program relies on a specific event model - for example, in
741	Gtk2 programs you have to rely on the Glib module - you should load the	1104	Gtk2 programs you have to rely on the Glib module - you should load the
742	event module before loading AnyEvent or any module that uses it: generally	1105	event module before loading AnyEvent or any module that uses it: generally
743	speaking, you should load it as early as possible. The reason is that	1106	speaking, you should load it as early as possible. The reason is that
744	modules might create watchers when they are loaded, and AnyEvent will	1107	modules might create watchers when they are loaded, and AnyEvent will
745	decide on the event model to use as soon as it creates watchers, and it	1108	decide on the event model to use as soon as it creates watchers, and it
746	might chose the wrong one unless you load the correct one yourself.	1109	might choose the wrong one unless you load the correct one yourself.
747		1110
748	You can chose to use a pure-perl implementation by loading the	1111	You can chose to use a pure-perl implementation by loading the
749	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1112	C<AnyEvent::Loop> module, which gives you similar behaviour
750	everywhere, but letting AnyEvent chose the model is generally better.	1113	everywhere, but letting AnyEvent chose the model is generally better.
751		1114
752	=head2 MAINLOOP EMULATION	1115	=head2 MAINLOOP EMULATION
753		1116
754	Sometimes (often for short test scripts, or even standalone programs who	1117	Sometimes (often for short test scripts, or even standalone programs who
…		…
767		1130
768		1131
769	=head1 OTHER MODULES	1132	=head1 OTHER MODULES
770		1133
771	The following is a non-exhaustive list of additional modules that use	1134	The following is a non-exhaustive list of additional modules that use
772	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1135	AnyEvent as a client and can therefore be mixed easily with other
773	in the same program. Some of the modules come with AnyEvent, some are	1136	AnyEvent modules and other event loops in the same program. Some of the
774	available via CPAN.	1137	modules come as part of AnyEvent, the others are available via CPAN (see
		1138	L<http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for
		1139	a longer non-exhaustive list), and the list is heavily biased towards
		1140	modules of the AnyEvent author himself :)
775		1141
776	=over 4	1142	=over 4
777		1143
778	=item L<AnyEvent::Util>	1144	=item L<AnyEvent::Util>
779		1145
780	Contains various utility functions that replace often-used but blocking	1146	Contains various utility functions that replace often-used blocking
781	functions such as C<inet_aton> by event-/callback-based versions.	1147	functions such as C<inet_aton> with event/callback-based versions.
782		1148
783	=item L<AnyEvent::Socket>	1149	=item L<AnyEvent::Socket>
784		1150
785	Provides various utility functions for (internet protocol) sockets,	1151	Provides various utility functions for (internet protocol) sockets,
786	addresses and name resolution. Also functions to create non-blocking tcp	1152	addresses and name resolution. Also functions to create non-blocking tcp
…		…
788		1154
789	=item L<AnyEvent::Handle>	1155	=item L<AnyEvent::Handle>
790		1156
791	Provide read and write buffers, manages watchers for reads and writes,	1157	Provide read and write buffers, manages watchers for reads and writes,
792	supports raw and formatted I/O, I/O queued and fully transparent and	1158	supports raw and formatted I/O, I/O queued and fully transparent and
793	non-blocking SSL/TLS.	1159	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
794		1160
795	=item L<AnyEvent::DNS>	1161	=item L<AnyEvent::DNS>
796		1162
797	Provides rich asynchronous DNS resolver capabilities.	1163	Provides rich asynchronous DNS resolver capabilities.
798		1164
		1165	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1166
		1167	Implement event-based interfaces to the protocols of the same name (for
		1168	the curious, IGS is the International Go Server and FCP is the Freenet
		1169	Client Protocol).
		1170
		1171	=item L<AnyEvent::Handle::UDP>
		1172
		1173	Here be danger!
		1174
		1175	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1176	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1177	its use of a stream-based API with a protocol that isn't streamable, that
		1178	the only way to improve it is to delete it.
		1179
		1180	It features data corruption (but typically only under load) and general
		1181	confusion. On top, the author is not only clueless about UDP but also
		1182	fact-resistant - some gems of his understanding: "connect doesn't work
		1183	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1184	packets", "I don't need to implement proper error checking as UDP doesn't
		1185	support error checking" and so on - he doesn't even understand what's
		1186	wrong with his module when it is explained to him.
		1187
799	=item L<AnyEvent::HTTP>	1188	=item L<AnyEvent::DBI>
800		1189
801	A simple-to-use HTTP library that is capable of making a lot of concurrent	1190	Executes L<DBI> requests asynchronously in a proxy process for you,
802	HTTP requests.	1191	notifying you in an event-based way when the operation is finished.
		1192
		1193	=item L<AnyEvent::AIO>
		1194
		1195	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1196	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1197	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1198	file I/O, and much more.
803		1199
804	=item L<AnyEvent::HTTPD>	1200	=item L<AnyEvent::HTTPD>
805		1201
806	Provides a simple web application server framework.	1202	A simple embedded webserver.
807		1203
808	=item L<AnyEvent::FastPing>	1204	=item L<AnyEvent::FastPing>
809		1205
810	The fastest ping in the west.	1206	The fastest ping in the west.
811		1207
812	=item L<AnyEvent::DBI>
813
814	Executes L<DBI> requests asynchronously in a proxy process.
815
816	=item L<AnyEvent::AIO>
817
818	Truly asynchronous I/O, should be in the toolbox of every event
819	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
820	together.
821
822	=item L<AnyEvent::BDB>
823
824	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
825	L<BDB> and AnyEvent together.
826
827	=item L<AnyEvent::GPSD>
828
829	A non-blocking interface to gpsd, a daemon delivering GPS information.
830
831	=item L<AnyEvent::IGS>
832
833	A non-blocking interface to the Internet Go Server protocol (used by
834	L<App::IGS>).
835
836	=item L<AnyEvent::IRC>
837
838	AnyEvent based IRC client module family (replacing the older Net::IRC3).
839
840	=item L<Net::XMPP2>
841
842	AnyEvent based XMPP (Jabber protocol) module family.
843
844	=item L<Net::FCP>
845
846	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
847	of AnyEvent.
848
849	=item L<Event::ExecFlow>
850
851	High level API for event-based execution flow control.
852
853	=item L<Coro>	1208	=item L<Coro>
854		1209
855	Has special support for AnyEvent via L<Coro::AnyEvent>.	1210	Has special support for AnyEvent via L<Coro::AnyEvent>.
856		1211
857	=item L<IO::Lambda>
858
859	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
860
861	=back	1212	=back
862		1213
863	=cut	1214	=cut
864		1215
865	package AnyEvent;	1216	package AnyEvent;
866		1217
867	no warnings;	1218	# basically a tuned-down version of common::sense
868	use strict qw(vars subs);	1219	sub common_sense {
		1220	# from common:.sense 3.4
		1221	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
		1222	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1223	$^H |= 0x00000600;
		1224	}
869		1225
		1226	BEGIN { AnyEvent::common_sense }
		1227
870	use Carp;	1228	use Carp ();
871		1229
872	our $VERSION = 4.341;	1230	our $VERSION = '6.01';
873	our $MODEL;	1231	our $MODEL;
874		1232
875	our $AUTOLOAD;
876	our @ISA;	1233	our @ISA;
877		1234
878	our @REGISTRY;	1235	our @REGISTRY;
879		1236
880	our $WIN32;	1237	our $VERBOSE;
881		1238
882	BEGIN {	1239	BEGIN {
883	my $win32 = ! ! ($^O =~ /mswin32/i);	1240	require "AnyEvent/constants.pl";
884	eval "sub WIN32(){ $win32 }";
885	}
886		1241
		1242	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
		1243
		1244	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1245	if ${^TAINT};
		1246
		1247	$ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
		1248	for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
		1249
		1250	@ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
		1251	if ${^TAINT};
		1252
887	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1253	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1254	}
		1255
		1256	our $MAX_SIGNAL_LATENCY = 10;
888		1257
889	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1258	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
890		1259
891	{	1260	{
892	my $idx;	1261	my $idx;
893	$PROTOCOL{$_} = ++$idx	1262	$PROTOCOL{$_} = ++$idx
894	for reverse split /\s*,\s*/,	1263	for reverse split /\s*,\s*/,
895	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1264	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
896	}	1265	}
897		1266
		1267	our @post_detect;
		1268
		1269	sub post_detect(&) {
		1270	my ($cb) = @_;
		1271
		1272	push @post_detect, $cb;
		1273
		1274	defined wantarray
		1275	? bless \$cb, "AnyEvent::Util::postdetect"
		1276	: ()
		1277	}
		1278
		1279	sub AnyEvent::Util::postdetect::DESTROY {
		1280	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1281	}
		1282
		1283	our $POSTPONE_W;
		1284	our @POSTPONE;
		1285
		1286	sub _postpone_exec {
		1287	undef $POSTPONE_W;
		1288
		1289	&{ shift @POSTPONE }
		1290	while @POSTPONE;
		1291	}
		1292
		1293	sub postpone(&) {
		1294	push @POSTPONE, shift;
		1295
		1296	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1297
		1298	()
		1299	}
		1300
		1301	sub log($$;@) {
		1302	# only load the big bloated module when we actually are about to log something
		1303	if ($_[0] <= $VERBOSE) { # also catches non-numeric levels(!)
		1304	require AnyEvent::Log;
		1305	# AnyEvent::Log overwrites this function
		1306	goto &log;
		1307	}
		1308
		1309	0 # not logged
		1310	}
		1311
		1312	if (length $ENV{PERL_ANYEVENT_LOG}) {
		1313	require AnyEvent::Log; # AnyEvent::Log does the thing for us
		1314	}
		1315
898	my @models = (	1316	our @models = (
899	[EV:: => AnyEvent::Impl::EV::],	1317	[EV:: => AnyEvent::Impl::EV:: , 1],
900	[Event:: => AnyEvent::Impl::Event::],	1318	[AnyEvent::Loop:: => AnyEvent::Impl::Perl:: , 1],
901	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
902	# everything below here will not be autoprobed	1319	# everything below here will not (normally) be autoprobed
903	# as the pureperl backend should work everywhere	1320	# as the pure perl backend should work everywhere
904	# and is usually faster	1321	# and is usually faster
		1322	[Event:: => AnyEvent::Impl::Event::, 1],
		1323	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1324	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1325	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
905	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1326	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
906	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
907	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
908	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1327	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
909	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1328	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
910	[Wx:: => AnyEvent::Impl::POE::],	1329	[Wx:: => AnyEvent::Impl::POE::],
911	[Prima:: => AnyEvent::Impl::POE::],	1330	[Prima:: => AnyEvent::Impl::POE::],
		1331	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
		1332	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
		1333	[FLTK:: => AnyEvent::Impl::FLTK2::],
912	);	1334	);
913		1335
914	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1336	our @isa_hook;
915		1337
916	our @post_detect;	1338	sub _isa_set {
		1339	my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
917		1340
		1341	@{"$pkg[$_-1]::ISA"} = $pkg[$_]
		1342	for 1 .. $#pkg;
		1343
		1344	grep $_ && $_->[1], @isa_hook
		1345	and AE::_reset ();
		1346	}
		1347
		1348	# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
		1349	sub _isa_hook($$;$) {
		1350	my ($i, $pkg, $reset_ae) = @_;
		1351
		1352	$isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
		1353
		1354	_isa_set;
		1355	}
		1356
		1357	# all autoloaded methods reserve the complete glob, not just the method slot.
		1358	# due to bugs in perls method cache implementation.
		1359	our @methods = qw(io timer time now now_update signal child idle condvar);
		1360
918	sub post_detect(&) {	1361	sub detect() {
919	my ($cb) = @_;	1362	return $MODEL if $MODEL; # some programs keep references to detect
920		1363
921	if ($MODEL) {	1364	local $!; # for good measure
922	$cb->();	1365	local $SIG{__DIE__}; # we use eval
923		1366
924	1	1367	# free some memory
		1368	*detect = sub () { $MODEL };
		1369	# undef &func doesn't correctly update the method cache. grmbl.
		1370	# so we delete the whole glob. grmbl.
		1371	# otoh, perl doesn't let me undef an active usb, but it lets me free
		1372	# a glob with an active sub. hrm. i hope it works, but perl is
		1373	# usually buggy in this department. sigh.
		1374	delete @{"AnyEvent::"}{@methods};
		1375	undef @methods;
		1376
		1377	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1378	my $model = $1;
		1379	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1380	if (eval "require $model") {
		1381	AnyEvent::log 7 => "loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.";
		1382	$MODEL = $model;
925	} else {	1383	} else {
926	push @post_detect, $cb;	1384	AnyEvent::log 5 => "unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
927		1385	}
928	defined wantarray
929	? bless \$cb, "AnyEvent::Util::PostDetect"
930	: ()
931	}	1386	}
932	}
933		1387
934	sub AnyEvent::Util::PostDetect::DESTROY {	1388	# check for already loaded models
935	@post_detect = grep $_ != ${$_[0]}, @post_detect;
936	}
937
938	sub detect() {
939	unless ($MODEL) {	1389	unless ($MODEL) {
940	no strict 'refs';	1390	for (@REGISTRY, @models) {
941	local $SIG{__DIE__};	1391	my ($package, $model) = @$_;
942		1392	if (${"$package\::VERSION"} > 0) {
943	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
944	my $model = "AnyEvent::Impl::$1";
945	if (eval "require $model") {	1393	if (eval "require $model") {
		1394	AnyEvent::log 7 => "autodetected model '$model', using it.";
946	$MODEL = $model;	1395	$MODEL = $model;
947	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1396	last;
948	} else {	1397	}
949	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;
950	}	1398	}
951	}	1399	}
952		1400
953	# check for already loaded models
954	unless ($MODEL) {	1401	unless ($MODEL) {
		1402	# try to autoload a model
955	for (@REGISTRY, @models) {	1403	for (@REGISTRY, @models) {
956	my ($package, $model) = @$_;	1404	my ($package, $model, $autoload) = @$_;
		1405	if (
		1406	$autoload
		1407	and eval "require $package"
957	if (${"$package\::VERSION"} > 0) {	1408	and ${"$package\::VERSION"} > 0
958	if (eval "require $model") {	1409	and eval "require $model"
		1410	) {
		1411	AnyEvent::log 7 => "autoloaded model '$model', using it.";
959	$MODEL = $model;	1412	$MODEL = $model;
960	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;
961	last;	1413	last;
962	}
963	}	1414	}
964	}	1415	}
965		1416
966	unless ($MODEL) {
967	# try to load a model
968
969	for (@REGISTRY, @models) {
970	my ($package, $model) = @$_;
971	if (eval "require $package"
972	and ${"$package\::VERSION"} > 0
973	and eval "require $model") {
974	$MODEL = $model;
975	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
976	last;
977	}
978	}
979
980	$MODEL	1417	$MODEL
981	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1418	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?";
982	}
983	}	1419	}
984
985	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
986
987	unshift @ISA, $MODEL;
988
989	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
990
991	(shift @post_detect)->() while @post_detect;
992	}	1420	}
993		1421
		1422	# free memory only needed for probing
		1423	undef @models;
		1424	undef @REGISTRY;
		1425
		1426	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1427
		1428	# now nuke some methods that are overridden by the backend.
		1429	# SUPER usage is not allowed in these.
		1430	for (qw(time signal child idle)) {
		1431	undef &{"AnyEvent::Base::$_"}
		1432	if defined &{"$MODEL\::$_"};
		1433	}
		1434
		1435	_isa_set;
		1436
		1437	# we're officially open!
		1438
		1439	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1440	require AnyEvent::Strict;
		1441	}
		1442
		1443	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1444	require AnyEvent::Debug;
		1445	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1446	}
		1447
		1448	if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1449	require AnyEvent::Socket;
		1450	require AnyEvent::Debug;
		1451
		1452	my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
		1453	$shell =~ s/\$\$/$$/g;
		1454
		1455	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1456	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1457	}
		1458
		1459	# now the anyevent environment is set up as the user told us to, so
		1460	# call the actual user code - post detects
		1461
		1462	(shift @post_detect)->() while @post_detect;
		1463	undef @post_detect;
		1464
		1465	*post_detect = sub(&) {
		1466	shift->();
		1467
		1468	undef
		1469	};
		1470
994	$MODEL	1471	$MODEL
995	}	1472	}
996		1473
997	sub AUTOLOAD {	1474	for my $name (@methods) {
998	(my $func = $AUTOLOAD) =~ s/.*://;	1475	*$name = sub {
999		1476	detect;
1000	$method{$func}	1477	# we use goto because
1001	or croak "$func: not a valid method for AnyEvent objects";	1478	# a) it makes the thunk more transparent
1002		1479	# b) it allows us to delete the thunk later
1003	detect unless $MODEL;	1480	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1004		1481	};
1005	my $class = shift;
1006	$class->$func (@_);
1007	}	1482	}
1008		1483
1009	# utility function to dup a filehandle. this is used by many backends	1484	# utility function to dup a filehandle. this is used by many backends
1010	# to support binding more than one watcher per filehandle (they usually	1485	# to support binding more than one watcher per filehandle (they usually
1011	# allow only one watcher per fd, so we dup it to get a different one).	1486	# allow only one watcher per fd, so we dup it to get a different one).
1012	sub _dupfh($$$$) {	1487	sub _dupfh($$;$$) {
1013	my ($poll, $fh, $r, $w) = @_;	1488	my ($poll, $fh, $r, $w) = @_;
1014		1489
1015	# cygwin requires the fh mode to be matching, unix doesn't	1490	# cygwin requires the fh mode to be matching, unix doesn't
1016	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1491	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1017	: $poll eq "w" ? ($w, ">")
1018	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1019		1492
1020	open my $fh2, "$mode&" . fileno $fh	1493	open my $fh2, $mode, $fh
1021	or die "cannot dup() filehandle: $!";	1494	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1022		1495
1023	# we assume CLOEXEC is already set by perl in all important cases	1496	# we assume CLOEXEC is already set by perl in all important cases
1024		1497
1025	($fh2, $rw)	1498	($fh2, $rw)
1026	}	1499	}
1027		1500
		1501	=head1 SIMPLIFIED AE API
		1502
		1503	Starting with version 5.0, AnyEvent officially supports a second, much
		1504	simpler, API that is designed to reduce the calling, typing and memory
		1505	overhead by using function call syntax and a fixed number of parameters.
		1506
		1507	See the L<AE> manpage for details.
		1508
		1509	=cut
		1510
		1511	package AE;
		1512
		1513	our $VERSION = $AnyEvent::VERSION;
		1514
		1515	sub _reset() {
		1516	eval q{
		1517	# fall back to the main API by default - backends and AnyEvent::Base
		1518	# implementations can overwrite these.
		1519
		1520	sub io($$$) {
		1521	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1522	}
		1523
		1524	sub timer($$$) {
		1525	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1526	}
		1527
		1528	sub signal($$) {
		1529	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1530	}
		1531
		1532	sub child($$) {
		1533	AnyEvent->child (pid => $_[0], cb => $_[1])
		1534	}
		1535
		1536	sub idle($) {
		1537	AnyEvent->idle (cb => $_[0]);
		1538	}
		1539
		1540	sub cv(;&) {
		1541	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1542	}
		1543
		1544	sub now() {
		1545	AnyEvent->now
		1546	}
		1547
		1548	sub now_update() {
		1549	AnyEvent->now_update
		1550	}
		1551
		1552	sub time() {
		1553	AnyEvent->time
		1554	}
		1555
		1556	*postpone = \&AnyEvent::postpone;
		1557	*log = \&AnyEvent::log;
		1558	};
		1559	die if $@;
		1560	}
		1561
		1562	BEGIN { _reset }
		1563
1028	package AnyEvent::Base;	1564	package AnyEvent::Base;
1029		1565
1030	# default implementation for now and time	1566	# default implementations for many methods
1031		1567
1032	BEGIN {	1568	sub time {
		1569	eval q{ # poor man's autoloading {}
		1570	# probe for availability of Time::HiRes
1033	if (eval "use Time::HiRes (); time (); 1") {	1571	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1572	*time = sub { Time::HiRes::time () };
1034	*_time = \&Time::HiRes::time;	1573	*AE::time = \& Time::HiRes::time ;
		1574	*now = \&time;
		1575	AnyEvent::log 8 => "AnyEvent: using Time::HiRes for sub-second timing accuracy.";
1035	# if (eval "use POSIX (); (POSIX::times())...	1576	# if (eval "use POSIX (); (POSIX::times())...
1036	} else {	1577	} else {
1037	*_time = sub { time }; # epic fail	1578	*time = sub { CORE::time };
		1579	*AE::time = sub (){ CORE::time };
		1580	*now = \&time;
		1581	AnyEvent::log 3 => "using built-in time(), WARNING, no sub-second resolution!";
		1582	}
		1583	};
		1584	die if $@;
		1585
		1586	&time
		1587	}
		1588
		1589	*now = \&time;
		1590	sub now_update { }
		1591
		1592	sub _poll {
		1593	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1594	}
		1595
		1596	# default implementation for ->condvar
		1597	# in fact, the default should not be overwritten
		1598
		1599	sub condvar {
		1600	eval q{ # poor man's autoloading {}
		1601	*condvar = sub {
		1602	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1603	};
		1604
		1605	*AE::cv = sub (;&) {
		1606	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1607	};
		1608	};
		1609	die if $@;
		1610
		1611	&condvar
		1612	}
		1613
		1614	# default implementation for ->signal
		1615
		1616	our $HAVE_ASYNC_INTERRUPT;
		1617
		1618	sub _have_async_interrupt() {
		1619	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1620	&& eval "use Async::Interrupt 1.02 (); 1")
		1621	unless defined $HAVE_ASYNC_INTERRUPT;
		1622
		1623	$HAVE_ASYNC_INTERRUPT
		1624	}
		1625
		1626	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1627	our (%SIG_ASY, %SIG_ASY_W);
		1628	our ($SIG_COUNT, $SIG_TW);
		1629
		1630	# install a dummy wakeup watcher to reduce signal catching latency
		1631	# used by Impls
		1632	sub _sig_add() {
		1633	unless ($SIG_COUNT++) {
		1634	# try to align timer on a full-second boundary, if possible
		1635	my $NOW = AE::now;
		1636
		1637	$SIG_TW = AE::timer
		1638	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1639	$MAX_SIGNAL_LATENCY,
		1640	sub { } # just for the PERL_ASYNC_CHECK
		1641	;
1038	}	1642	}
1039	}	1643	}
1040		1644
1041	sub time { _time }	1645	sub _sig_del {
1042	sub now { _time }	1646	undef $SIG_TW
1043		1647	unless --$SIG_COUNT;
1044	# default implementation for ->condvar
1045
1046	sub condvar {
1047	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
1048	}	1648	}
1049		1649
1050	# default implementation for ->signal	1650	our $_sig_name_init; $_sig_name_init = sub {
		1651	eval q{ # poor man's autoloading {}
		1652	undef $_sig_name_init;
1051		1653
1052	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1654	if (_have_async_interrupt) {
		1655	*sig2num = \&Async::Interrupt::sig2num;
		1656	*sig2name = \&Async::Interrupt::sig2name;
		1657	} else {
		1658	require Config;
1053		1659
1054	sub _signal_exec {	1660	my %signame2num;
1055	while (%SIG_EV) {	1661	@signame2num{ split ' ', $Config::Config{sig_name} }
1056	sysread $SIGPIPE_R, my $dummy, 4;	1662	= split ' ', $Config::Config{sig_num};
1057	for (keys %SIG_EV) {	1663
1058	delete $SIG_EV{$_};	1664	my @signum2name;
1059	$_->() for values %{ $SIG_CB{$_} || {} };	1665	@signum2name[values %signame2num] = keys %signame2num;
		1666
		1667	*sig2num = sub($) {
		1668	$_[0] > 0 ? shift : $signame2num{+shift}
		1669	};
		1670	*sig2name = sub ($) {
		1671	$_[0] > 0 ? $signum2name[+shift] : shift
		1672	};
1060	}	1673	}
1061	}	1674	};
1062	}	1675	die if $@;
		1676	};
		1677
		1678	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1679	sub sig2name($) { &$_sig_name_init; &sig2name }
1063		1680
1064	sub signal {	1681	sub signal {
1065	my (undef, %arg) = @_;	1682	eval q{ # poor man's autoloading {}
		1683	# probe for availability of Async::Interrupt
		1684	if (_have_async_interrupt) {
		1685	AnyEvent::log 8 => "using Async::Interrupt for race-free signal handling.";
1066		1686
1067	unless ($SIGPIPE_R) {	1687	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1068	if (AnyEvent::WIN32) {	1688	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1069	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();	1689
1070	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1071	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1072	} else {	1690	} else {
		1691	AnyEvent::log 8 => "using emulated perl signal handling with latency timer.";
		1692
		1693	if (AnyEvent::WIN32) {
		1694	require AnyEvent::Util;
		1695
		1696	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1697	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1698	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1699	} else {
1073	pipe $SIGPIPE_R, $SIGPIPE_W;	1700	pipe $SIGPIPE_R, $SIGPIPE_W;
1074	require Fcntl;
1075	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1701	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1076	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1702	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1703
		1704	# not strictly required, as $^F is normally 2, but let's make sure...
		1705	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1706	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1707	}
		1708
		1709	$SIGPIPE_R
		1710	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1711
		1712	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1077	}	1713	}
1078		1714
1079	$SIGPIPE_R	1715	*signal = $HAVE_ASYNC_INTERRUPT
1080	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1716	? sub {
		1717	my (undef, %arg) = @_;
1081		1718
1082	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1719	# async::interrupt
1083	}
1084
1085	my $signal = uc $arg{signal}	1720	my $signal = sig2num $arg{signal};
1086	or Carp::croak "required option 'signal' is missing";
1087
1088	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1721	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1722
		1723	$SIG_ASY{$signal} ||= new Async::Interrupt
		1724	cb => sub { undef $SIG_EV{$signal} },
		1725	signal => $signal,
		1726	pipe => [$SIGPIPE_R->filenos],
		1727	pipe_autodrain => 0,
		1728	;
		1729
		1730	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1731	}
		1732	: sub {
		1733	my (undef, %arg) = @_;
		1734
		1735	# pure perl
		1736	my $signal = sig2name $arg{signal};
		1737	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1738
1089	$SIG{$signal} ||= sub {	1739	$SIG{$signal} ||= sub {
		1740	local $!;
1090	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1741	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1091	undef $SIG_EV{$signal};	1742	undef $SIG_EV{$signal};
		1743	};
		1744
		1745	# can't do signal processing without introducing races in pure perl,
		1746	# so limit the signal latency.
		1747	_sig_add;
		1748
		1749	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1750	}
		1751	;
		1752
		1753	*AnyEvent::Base::signal::DESTROY = sub {
		1754	my ($signal, $cb) = @{$_[0]};
		1755
		1756	_sig_del;
		1757
		1758	delete $SIG_CB{$signal}{$cb};
		1759
		1760	$HAVE_ASYNC_INTERRUPT
		1761	? delete $SIG_ASY{$signal}
		1762	: # delete doesn't work with older perls - they then
		1763	# print weird messages, or just unconditionally exit
		1764	# instead of getting the default action.
		1765	undef $SIG{$signal}
		1766	unless keys %{ $SIG_CB{$signal} };
		1767	};
		1768
		1769	*_signal_exec = sub {
		1770	$HAVE_ASYNC_INTERRUPT
		1771	? $SIGPIPE_R->drain
		1772	: sysread $SIGPIPE_R, (my $dummy), 9;
		1773
		1774	while (%SIG_EV) {
		1775	for (keys %SIG_EV) {
		1776	delete $SIG_EV{$_};
		1777	&$_ for values %{ $SIG_CB{$_} || {} };
		1778	}
		1779	}
		1780	};
1092	};	1781	};
		1782	die if $@;
1093		1783
1094	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1784	&signal
1095	}
1096
1097	sub AnyEvent::Base::Signal::DESTROY {
1098	my ($signal, $cb) = @{$_[0]};
1099
1100	delete $SIG_CB{$signal}{$cb};
1101
1102	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1103	}	1785	}
1104		1786
1105	# default implementation for ->child	1787	# default implementation for ->child
1106		1788
1107	our %PID_CB;	1789	our %PID_CB;
1108	our $CHLD_W;	1790	our $CHLD_W;
1109	our $CHLD_DELAY_W;	1791	our $CHLD_DELAY_W;
1110	our $PID_IDLE;
1111	our $WNOHANG;
1112		1792
1113	sub _child_wait {	1793	# used by many Impl's
1114	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1794	sub _emit_childstatus($$) {
		1795	my (undef, $rpid, $rstatus) = @_;
		1796
		1797	$_->($rpid, $rstatus)
1115	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1798	for values %{ $PID_CB{$rpid} || {} },
1116	(values %{ $PID_CB{0} || {} });	1799	values %{ $PID_CB{0} || {} };
1117	}
1118
1119	undef $PID_IDLE;
1120	}
1121
1122	sub _sigchld {
1123	# make sure we deliver these changes "synchronous" with the event loop.
1124	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
1125	undef $CHLD_DELAY_W;
1126	&_child_wait;
1127	});
1128	}	1800	}
1129		1801
1130	sub child {	1802	sub child {
		1803	eval q{ # poor man's autoloading {}
		1804	*_sigchld = sub {
		1805	my $pid;
		1806
		1807	AnyEvent->_emit_childstatus ($pid, $?)
		1808	while ($pid = waitpid -1, WNOHANG) > 0;
		1809	};
		1810
		1811	*child = sub {
1131	my (undef, %arg) = @_;	1812	my (undef, %arg) = @_;
1132		1813
1133	defined (my $pid = $arg{pid} + 0)	1814	my $pid = $arg{pid};
1134	or Carp::croak "required option 'pid' is missing";	1815	my $cb = $arg{cb};
1135		1816
1136	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1817	$PID_CB{$pid}{$cb+0} = $cb;
1137		1818
1138	unless ($WNOHANG) {
1139	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1140	}
1141
1142	unless ($CHLD_W) {	1819	unless ($CHLD_W) {
1143	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1820	$CHLD_W = AE::signal CHLD => \&_sigchld;
1144	# child could be a zombie already, so make at least one round	1821	# child could be a zombie already, so make at least one round
1145	&_sigchld;	1822	&_sigchld;
1146	}	1823	}
1147		1824
1148	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1825	bless [$pid, $cb+0], "AnyEvent::Base::child"
1149	}	1826	};
1150		1827
1151	sub AnyEvent::Base::Child::DESTROY {	1828	*AnyEvent::Base::child::DESTROY = sub {
1152	my ($pid, $cb) = @{$_[0]};	1829	my ($pid, $icb) = @{$_[0]};
1153		1830
1154	delete $PID_CB{$pid}{$cb};	1831	delete $PID_CB{$pid}{$icb};
1155	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1832	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1156		1833
1157	undef $CHLD_W unless keys %PID_CB;	1834	undef $CHLD_W unless keys %PID_CB;
		1835	};
		1836	};
		1837	die if $@;
		1838
		1839	&child
		1840	}
		1841
		1842	# idle emulation is done by simply using a timer, regardless
		1843	# of whether the process is idle or not, and not letting
		1844	# the callback use more than 50% of the time.
		1845	sub idle {
		1846	eval q{ # poor man's autoloading {}
		1847	*idle = sub {
		1848	my (undef, %arg) = @_;
		1849
		1850	my ($cb, $w, $rcb) = $arg{cb};
		1851
		1852	$rcb = sub {
		1853	if ($cb) {
		1854	$w = AE::time;
		1855	&$cb;
		1856	$w = AE::time - $w;
		1857
		1858	# never use more then 50% of the time for the idle watcher,
		1859	# within some limits
		1860	$w = 0.0001 if $w < 0.0001;
		1861	$w = 5 if $w > 5;
		1862
		1863	$w = AE::timer $w, 0, $rcb;
		1864	} else {
		1865	# clean up...
		1866	undef $w;
		1867	undef $rcb;
		1868	}
		1869	};
		1870
		1871	$w = AE::timer 0.05, 0, $rcb;
		1872
		1873	bless \\$cb, "AnyEvent::Base::idle"
		1874	};
		1875
		1876	*AnyEvent::Base::idle::DESTROY = sub {
		1877	undef $${$_[0]};
		1878	};
		1879	};
		1880	die if $@;
		1881
		1882	&idle
1158	}	1883	}
1159		1884
1160	package AnyEvent::CondVar;	1885	package AnyEvent::CondVar;
1161		1886
1162	our @ISA = AnyEvent::CondVar::Base::;	1887	our @ISA = AnyEvent::CondVar::Base::;
1163		1888
		1889	# only to be used for subclassing
		1890	sub new {
		1891	my $class = shift;
		1892	bless AnyEvent->condvar (@_), $class
		1893	}
		1894
1164	package AnyEvent::CondVar::Base;	1895	package AnyEvent::CondVar::Base;
1165		1896
1166	use overload	1897	#use overload
1167	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1898	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1168	fallback => 1;	1899	# fallback => 1;
		1900
		1901	# save 300+ kilobytes by dirtily hardcoding overloading
		1902	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1903	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1904	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1905	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1906
		1907	our $WAITING;
1169		1908
1170	sub _send {	1909	sub _send {
1171	# nop	1910	# nop
		1911	}
		1912
		1913	sub _wait {
		1914	AnyEvent->_poll until $_[0]{_ae_sent};
1172	}	1915	}
1173		1916
1174	sub send {	1917	sub send {
1175	my $cv = shift;	1918	my $cv = shift;
1176	$cv->{_ae_sent} = [@_];	1919	$cv->{_ae_sent} = [@_];
…		…
1185		1928
1186	sub ready {	1929	sub ready {
1187	$_[0]{_ae_sent}	1930	$_[0]{_ae_sent}
1188	}	1931	}
1189		1932
1190	sub _wait {
1191	AnyEvent->one_event while !$_[0]{_ae_sent};
1192	}
1193
1194	sub recv {	1933	sub recv {
		1934	unless ($_[0]{_ae_sent}) {
		1935	$WAITING
		1936	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1937
		1938	local $WAITING = 1;
1195	$_[0]->_wait;	1939	$_[0]->_wait;
		1940	}
1196		1941
1197	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1942	$_[0]{_ae_croak}
1198	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1943	and Carp::croak $_[0]{_ae_croak};
		1944
		1945	wantarray
		1946	? @{ $_[0]{_ae_sent} }
		1947	: $_[0]{_ae_sent}[0]
1199	}	1948	}
1200		1949
1201	sub cb {	1950	sub cb {
1202	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1951	my $cv = shift;
		1952
		1953	@_
		1954	and $cv->{_ae_cb} = shift
		1955	and $cv->{_ae_sent}
		1956	and (delete $cv->{_ae_cb})->($cv);
		1957
1203	$_[0]{_ae_cb}	1958	$cv->{_ae_cb}
1204	}	1959	}
1205		1960
1206	sub begin {	1961	sub begin {
1207	++$_[0]{_ae_counter};	1962	++$_[0]{_ae_counter};
1208	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1963	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1213	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	1968	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1214	}	1969	}
1215		1970
1216	# undocumented/compatibility with pre-3.4	1971	# undocumented/compatibility with pre-3.4
1217	*broadcast = \&send;	1972	*broadcast = \&send;
1218	*wait = \&_wait;	1973	*wait = \&recv;
1219		1974
1220	=head1 ERROR AND EXCEPTION HANDLING	1975	=head1 ERROR AND EXCEPTION HANDLING
1221		1976
1222	In general, AnyEvent does not do any error handling - it relies on the	1977	In general, AnyEvent does not do any error handling - it relies on the
1223	caller to do that if required. The L<AnyEvent::Strict> module (see also	1978	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1235	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and	1990	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1236	so on.	1991	so on.
1237		1992
1238	=head1 ENVIRONMENT VARIABLES	1993	=head1 ENVIRONMENT VARIABLES
1239		1994
1240	The following environment variables are used by this module or its	1995	AnyEvent supports a number of environment variables that tune the
1241	submodules:	1996	runtime behaviour. They are usually evaluated when AnyEvent is
		1997	loaded, initialised, or a submodule that uses them is loaded. Many of
		1998	them also cause AnyEvent to load additional modules - for example,
		1999	C<PERL_ANYEVENT_DEBUG_WRAP> causes the L<AnyEvent::Debug> module to be
		2000	loaded.
		2001
		2002	All the environment variables documented here start with
		2003	C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
		2004	namespace. Other modules are encouraged (but by no means required) to use
		2005	C<PERL_ANYEVENT_SUBMODULE> if they have registered the AnyEvent::Submodule
		2006	namespace on CPAN, for any submodule. For example, L<AnyEvent::HTTP> could
		2007	be expected to use C<PERL_ANYEVENT_HTTP_PROXY> (it should not access env
		2008	variables starting with C<AE_>, see below).
		2009
		2010	All variables can also be set via the C<AE_> prefix, that is, instead
		2011	of setting C<PERL_ANYEVENT_VERBOSE> you can also set C<AE_VERBOSE>. In
		2012	case there is a clash btween anyevent and another program that uses
		2013	C<AE_something> you can set the corresponding C<PERL_ANYEVENT_something>
		2014	variable to the empty string, as those variables take precedence.
		2015
		2016	When AnyEvent is first loaded, it copies all C<AE_xxx> env variables
		2017	to their C<PERL_ANYEVENT_xxx> counterpart unless that variable already
		2018	exists. If taint mode is on, then AnyEvent will remove I<all> environment
		2019	variables starting with C<PERL_ANYEVENT_> from C<%ENV> (or replace them
		2020	with C<undef> or the empty string, if the corresaponding C<AE_> variable
		2021	is set).
		2022
		2023	The exact algorithm is currently:
		2024
		2025	1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
		2026	2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
		2027	3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
		2028
		2029	This ensures that child processes will not see the C<AE_> variables.
		2030
		2031	The following environment variables are currently known to AnyEvent:
1242		2032
1243	=over 4	2033	=over 4
1244		2034
1245	=item C<PERL_ANYEVENT_VERBOSE>	2035	=item C<PERL_ANYEVENT_VERBOSE>
1246		2036
1247	By default, AnyEvent will be completely silent except in fatal	2037	By default, AnyEvent will be completely silent except in fatal
1248	conditions. You can set this environment variable to make AnyEvent more	2038	conditions. You can set this environment variable to make AnyEvent more
1249	talkative.	2039	talkative. If you want to do more than just set the global logging level
		2040	you should have a look at C<PERL_ANYEVENT_LOG>, which allows much more
		2041	complex specifications.
1250		2042
1251	When set to C<1> or higher, causes AnyEvent to warn about unexpected	2043	When set to C<5> or higher (warn), causes AnyEvent to warn about unexpected
1252	conditions, such as not being able to load the event model specified by	2044	conditions, such as not being able to load the event model specified by
1253	C<PERL_ANYEVENT_MODEL>.	2045	C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an exception - this
		2046	is the minimum recommended level.
1254		2047
1255	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	2048	When set to C<7> or higher (info), cause AnyEvent to report which event model it
1256	model it chooses.	2049	chooses.
		2050
		2051	When set to C<8> or higher (debug), then AnyEvent will report extra information on
		2052	which optional modules it loads and how it implements certain features.
		2053
		2054	=item C<PERL_ANYEVENT_LOG>
		2055
		2056	Accepts rather complex logging specifications. For example, you could log
		2057	all C<debug> messages of some module to stderr, warnings and above to
		2058	stderr, and errors and above to syslog, with:
		2059
		2060	PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
		2061
		2062	For the rather extensive details, see L<AnyEvent::Log>.
		2063
		2064	This variable is evaluated when AnyEvent (or L<AnyEvent::Log>) is loaded,
		2065	so will take effect even before AnyEvent has initialised itself.
		2066
		2067	Note that specifying this environment variable causes the L<AnyEvent::Log>
		2068	module to be loaded, while C<PERL_ANYEVENT_VERBOSE> does not, so only
		2069	using the latter saves a few hundred kB of memory until the first message
		2070	is being logged.
1257		2071
1258	=item C<PERL_ANYEVENT_STRICT>	2072	=item C<PERL_ANYEVENT_STRICT>
1259		2073
1260	AnyEvent does not do much argument checking by default, as thorough	2074	AnyEvent does not do much argument checking by default, as thorough
1261	argument checking is very costly. Setting this variable to a true value	2075	argument checking is very costly. Setting this variable to a true value
1262	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	2076	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1263	check the arguments passed to most method calls. If it finds any problems	2077	check the arguments passed to most method calls. If it finds any problems,
1264	it will croak.	2078	it will croak.
1265		2079
1266	In other words, enables "strict" mode.	2080	In other words, enables "strict" mode.
1267		2081
1268	Unlike C<use strict>, it is definitely recommended ot keep it off in	2082	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1269	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	2083	>>, it is definitely recommended to keep it off in production. Keeping
1270	developing programs can be very useful, however.	2084	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		2085	can be very useful, however.
		2086
		2087	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		2088
		2089	If this env variable is set, then its contents will be interpreted by
		2090	C<AnyEvent::Socket::parse_hostport> (after replacing every occurance of
		2091	C<$$> by the process pid) and an C<AnyEvent::Debug::shell> is bound on
		2092	that port. The shell object is saved in C<$AnyEvent::Debug::SHELL>.
		2093
		2094	This happens when the first watcher is created.
		2095
		2096	For example, to bind a debug shell on a unix domain socket in
		2097	F<< /tmp/debug<pid>.sock >>, you could use this:
		2098
		2099	PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
		2100
		2101	Note that creating sockets in F</tmp> is very unsafe on multiuser
		2102	systems.
		2103
		2104	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		2105
		2106	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		2107	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
1271		2108
1272	=item C<PERL_ANYEVENT_MODEL>	2109	=item C<PERL_ANYEVENT_MODEL>
1273		2110
1274	This can be used to specify the event model to be used by AnyEvent, before	2111	This can be used to specify the event model to be used by AnyEvent, before
1275	auto detection and -probing kicks in. It must be a string consisting	2112	auto detection and -probing kicks in.
1276	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	2113
		2114	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		2115	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1277	and the resulting module name is loaded and if the load was successful,	2116	resulting module name is loaded and - if the load was successful - used as
1278	used as event model. If it fails to load AnyEvent will proceed with	2117	event model backend. If it fails to load then AnyEvent will proceed with
1279	auto detection and -probing.	2118	auto detection and -probing.
1280		2119
1281	This functionality might change in future versions.	2120	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		2121	nothing gets prepended and the module name is used as-is (hint: C<::> at
		2122	the end of a string designates a module name and quotes it appropriately).
1282		2123
1283	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	2124	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1284	could start your program like this:	2125	could start your program like this:
1285		2126
1286	PERL_ANYEVENT_MODEL=Perl perl ...	2127	PERL_ANYEVENT_MODEL=Perl perl ...
1287		2128
1288	=item C<PERL_ANYEVENT_PROTOCOLS>	2129	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
1304	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>	2145	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1305	- only support IPv4, never try to resolve or contact IPv6	2146	- only support IPv4, never try to resolve or contact IPv6
1306	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or	2147	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1307	IPv6, but prefer IPv6 over IPv4.	2148	IPv6, but prefer IPv6 over IPv4.
1308		2149
		2150	=item C<PERL_ANYEVENT_HOSTS>
		2151
		2152	This variable, if specified, overrides the F</etc/hosts> file used by
		2153	L<AnyEvent::Socket>C<::resolve_sockaddr>, i.e. hosts aliases will be read
		2154	from that file instead.
		2155
1309	=item C<PERL_ANYEVENT_EDNS0>	2156	=item C<PERL_ANYEVENT_EDNS0>
1310		2157
1311	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension	2158	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension for
1312	for DNS. This extension is generally useful to reduce DNS traffic, but	2159	DNS. This extension is generally useful to reduce DNS traffic, especially
1313	some (broken) firewalls drop such DNS packets, which is why it is off by	2160	when DNSSEC is involved, but some (broken) firewalls drop such DNS
1314	default.	2161	packets, which is why it is off by default.
1315		2162
1316	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce	2163	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1317	EDNS0 in its DNS requests.	2164	EDNS0 in its DNS requests.
1318		2165
1319	=item C<PERL_ANYEVENT_MAX_FORKS>	2166	=item C<PERL_ANYEVENT_MAX_FORKS>
1320		2167
1321	The maximum number of child processes that C<AnyEvent::Util::fork_call>	2168	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1322	will create in parallel.	2169	will create in parallel.
		2170
		2171	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		2172
		2173	The default value for the C<max_outstanding> parameter for the default DNS
		2174	resolver - this is the maximum number of parallel DNS requests that are
		2175	sent to the DNS server.
		2176
		2177	=item C<PERL_ANYEVENT_RESOLV_CONF>
		2178
		2179	The absolute path to a F<resolv.conf>-style file to use instead of
		2180	F</etc/resolv.conf> (or the OS-specific configuration) in the default
		2181	resolver, or the empty string to select the default configuration.
		2182
		2183	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		2184
		2185	When neither C<ca_file> nor C<ca_path> was specified during
		2186	L<AnyEvent::TLS> context creation, and either of these environment
		2187	variables are nonempty, they will be used to specify CA certificate
		2188	locations instead of a system-dependent default.
		2189
		2190	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		2191
		2192	When these are set to C<1>, then the respective modules are not
		2193	loaded. Mostly good for testing AnyEvent itself.
1323		2194
1324	=back	2195	=back
1325		2196
1326	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	2197	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1327		2198
…		…
1385	warn "read: $input\n"; # output what has been read	2256	warn "read: $input\n"; # output what has been read
1386	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2257	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1387	},	2258	},
1388	);	2259	);
1389		2260
1390	my $time_watcher; # can only be used once
1391
1392	sub new_timer {
1393	$timer = AnyEvent->timer (after => 1, cb => sub {	2261	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1394	warn "timeout\n"; # print 'timeout' about every second	2262	warn "timeout\n"; # print 'timeout' at most every second
1395	&new_timer; # and restart the time
1396	});	2263	});
1397	}
1398
1399	new_timer; # create first timer
1400		2264
1401	$cv->recv; # wait until user enters /^q/i	2265	$cv->recv; # wait until user enters /^q/i
1402		2266
1403	=head1 REAL-WORLD EXAMPLE	2267	=head1 REAL-WORLD EXAMPLE
1404		2268
…		…
1477		2341
1478	The actual code goes further and collects all errors (C<die>s, exceptions)	2342	The actual code goes further and collects all errors (C<die>s, exceptions)
1479	that occurred during request processing. The C<result> method detects	2343	that occurred during request processing. The C<result> method detects
1480	whether an exception as thrown (it is stored inside the $txn object)	2344	whether an exception as thrown (it is stored inside the $txn object)
1481	and just throws the exception, which means connection errors and other	2345	and just throws the exception, which means connection errors and other
1482	problems get reported tot he code that tries to use the result, not in a	2346	problems get reported to the code that tries to use the result, not in a
1483	random callback.	2347	random callback.
1484		2348
1485	All of this enables the following usage styles:	2349	All of this enables the following usage styles:
1486		2350
1487	1. Blocking:	2351	1. Blocking:
…		…
1535	through AnyEvent. The benchmark creates a lot of timers (with a zero	2399	through AnyEvent. The benchmark creates a lot of timers (with a zero
1536	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2400	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1537	which it is), lets them fire exactly once and destroys them again.	2401	which it is), lets them fire exactly once and destroys them again.
1538		2402
1539	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2403	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1540	distribution.	2404	distribution. It uses the L<AE> interface, which makes a real difference
		2405	for the EV and Perl backends only.
1541		2406
1542	=head3 Explanation of the columns	2407	=head3 Explanation of the columns
1543		2408
1544	I<watcher> is the number of event watchers created/destroyed. Since	2409	I<watcher> is the number of event watchers created/destroyed. Since
1545	different event models feature vastly different performances, each event	2410	different event models feature vastly different performances, each event
…		…
1566	watcher.	2431	watcher.
1567		2432
1568	=head3 Results	2433	=head3 Results
1569		2434
1570	name watchers bytes create invoke destroy comment	2435	name watchers bytes create invoke destroy comment
1571	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2436	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1572	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2437	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1573	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2438	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1574	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2439	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1575	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2440	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1576	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2441	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2442	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2443	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1577	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2444	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1578	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2445	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1579	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2446	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1580	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2447	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1581		2448
1582	=head3 Discussion	2449	=head3 Discussion
1583		2450
1584	The benchmark does I<not> measure scalability of the event loop very	2451	The benchmark does I<not> measure scalability of the event loop very
1585	well. For example, a select-based event loop (such as the pure perl one)	2452	well. For example, a select-based event loop (such as the pure perl one)
…		…
1597	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2464	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1598	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2465	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1599	cycles with POE.	2466	cycles with POE.
1600		2467
1601	C<EV> is the sole leader regarding speed and memory use, which are both	2468	C<EV> is the sole leader regarding speed and memory use, which are both
1602	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2469	maximal/minimal, respectively. When using the L<AE> API there is zero
		2470	overhead (when going through the AnyEvent API create is about 5-6 times
		2471	slower, with other times being equal, so still uses far less memory than
1603	far less memory than any other event loop and is still faster than Event	2472	any other event loop and is still faster than Event natively).
1604	natively.
1605		2473
1606	The pure perl implementation is hit in a few sweet spots (both the	2474	The pure perl implementation is hit in a few sweet spots (both the
1607	constant timeout and the use of a single fd hit optimisations in the perl	2475	constant timeout and the use of a single fd hit optimisations in the perl
1608	interpreter and the backend itself). Nevertheless this shows that it	2476	interpreter and the backend itself). Nevertheless this shows that it
1609	adds very little overhead in itself. Like any select-based backend its	2477	adds very little overhead in itself. Like any select-based backend its
1610	performance becomes really bad with lots of file descriptors (and few of	2478	performance becomes really bad with lots of file descriptors (and few of
1611	them active), of course, but this was not subject of this benchmark.	2479	them active), of course, but this was not subject of this benchmark.
1612		2480
1613	The C<Event> module has a relatively high setup and callback invocation	2481	The C<Event> module has a relatively high setup and callback invocation
1614	cost, but overall scores in on the third place.	2482	cost, but overall scores in on the third place.
		2483
		2484	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2485	when using its pure perl backend.
1615		2486
1616	C<Glib>'s memory usage is quite a bit higher, but it features a	2487	C<Glib>'s memory usage is quite a bit higher, but it features a
1617	faster callback invocation and overall ends up in the same class as	2488	faster callback invocation and overall ends up in the same class as
1618	C<Event>. However, Glib scales extremely badly, doubling the number of	2489	C<Event>. However, Glib scales extremely badly, doubling the number of
1619	watchers increases the processing time by more than a factor of four,	2490	watchers increases the processing time by more than a factor of four,
…		…
1654	(even when used without AnyEvent), but most event loops have acceptable	2525	(even when used without AnyEvent), but most event loops have acceptable
1655	performance with or without AnyEvent.	2526	performance with or without AnyEvent.
1656		2527
1657	=item * The overhead AnyEvent adds is usually much smaller than the overhead of	2528	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
1658	the actual event loop, only with extremely fast event loops such as EV	2529	the actual event loop, only with extremely fast event loops such as EV
1659	adds AnyEvent significant overhead.	2530	does AnyEvent add significant overhead.
1660		2531
1661	=item * You should avoid POE like the plague if you want performance or	2532	=item * You should avoid POE like the plague if you want performance or
1662	reasonable memory usage.	2533	reasonable memory usage.
1663		2534
1664	=back	2535	=back
…		…
1680	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2551	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1681	(1%) are active. This mirrors the activity of large servers with many	2552	(1%) are active. This mirrors the activity of large servers with many
1682	connections, most of which are idle at any one point in time.	2553	connections, most of which are idle at any one point in time.
1683		2554
1684	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2555	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1685	distribution.	2556	distribution. It uses the L<AE> interface, which makes a real difference
		2557	for the EV and Perl backends only.
1686		2558
1687	=head3 Explanation of the columns	2559	=head3 Explanation of the columns
1688		2560
1689	I<sockets> is the number of sockets, and twice the number of "servers" (as	2561	I<sockets> is the number of sockets, and twice the number of "servers" (as
1690	each server has a read and write socket end).	2562	each server has a read and write socket end).
…		…
1697	it to another server. This includes deleting the old timeout and creating	2569	it to another server. This includes deleting the old timeout and creating
1698	a new one that moves the timeout into the future.	2570	a new one that moves the timeout into the future.
1699		2571
1700	=head3 Results	2572	=head3 Results
1701		2573
1702	name sockets create request	2574	name sockets create request
1703	EV 20000 69.01 11.16	2575	EV 20000 62.66 7.99
1704	Perl 20000 73.32 35.87	2576	Perl 20000 68.32 32.64
1705	Event 20000 212.62 257.32	2577	IOAsync 20000 174.06 101.15 epoll
1706	Glib 20000 651.16 1896.30	2578	IOAsync 20000 174.67 610.84 poll
		2579	Event 20000 202.69 242.91
		2580	Glib 20000 557.01 1689.52
1707	POE 20000 349.67 12317.24 uses POE::Loop::Event	2581	POE 20000 341.54 12086.32 uses POE::Loop::Event
1708		2582
1709	=head3 Discussion	2583	=head3 Discussion
1710		2584
1711	This benchmark I<does> measure scalability and overall performance of the	2585	This benchmark I<does> measure scalability and overall performance of the
1712	particular event loop.	2586	particular event loop.
…		…
1714	EV is again fastest. Since it is using epoll on my system, the setup time	2588	EV is again fastest. Since it is using epoll on my system, the setup time
1715	is relatively high, though.	2589	is relatively high, though.
1716		2590
1717	Perl surprisingly comes second. It is much faster than the C-based event	2591	Perl surprisingly comes second. It is much faster than the C-based event
1718	loops Event and Glib.	2592	loops Event and Glib.
		2593
		2594	IO::Async performs very well when using its epoll backend, and still quite
		2595	good compared to Glib when using its pure perl backend.
1719		2596
1720	Event suffers from high setup time as well (look at its code and you will	2597	Event suffers from high setup time as well (look at its code and you will
1721	understand why). Callback invocation also has a high overhead compared to	2598	understand why). Callback invocation also has a high overhead compared to
1722	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2599	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1723	uses select or poll in basically all documented configurations.	2600	uses select or poll in basically all documented configurations.
…		…
1786	=item * C-based event loops perform very well with small number of	2663	=item * C-based event loops perform very well with small number of
1787	watchers, as the management overhead dominates.	2664	watchers, as the management overhead dominates.
1788		2665
1789	=back	2666	=back
1790		2667
		2668	=head2 THE IO::Lambda BENCHMARK
		2669
		2670	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2671	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2672	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2673	shouldn't come as a surprise to anybody). As such, the benchmark is
		2674	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2675	very optimal. But how would AnyEvent compare when used without the extra
		2676	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2677
		2678	The benchmark itself creates an echo-server, and then, for 500 times,
		2679	connects to the echo server, sends a line, waits for the reply, and then
		2680	creates the next connection. This is a rather bad benchmark, as it doesn't
		2681	test the efficiency of the framework or much non-blocking I/O, but it is a
		2682	benchmark nevertheless.
		2683
		2684	name runtime
		2685	Lambda/select 0.330 sec
		2686	+ optimized 0.122 sec
		2687	Lambda/AnyEvent 0.327 sec
		2688	+ optimized 0.138 sec
		2689	Raw sockets/select 0.077 sec
		2690	POE/select, components 0.662 sec
		2691	POE/select, raw sockets 0.226 sec
		2692	POE/select, optimized 0.404 sec
		2693
		2694	AnyEvent/select/nb 0.085 sec
		2695	AnyEvent/EV/nb 0.068 sec
		2696	+state machine 0.134 sec
		2697
		2698	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2699	benchmarks actually make blocking connects and use 100% blocking I/O,
		2700	defeating the purpose of an event-based solution. All of the newly
		2701	written AnyEvent benchmarks use 100% non-blocking connects (using
		2702	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2703	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2704	generally require a lot more bookkeeping and event handling than blocking
		2705	connects (which involve a single syscall only).
		2706
		2707	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2708	offers similar expressive power as POE and IO::Lambda, using conventional
		2709	Perl syntax. This means that both the echo server and the client are 100%
		2710	non-blocking, further placing it at a disadvantage.
		2711
		2712	As you can see, the AnyEvent + EV combination even beats the
		2713	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2714	backend easily beats IO::Lambda and POE.
		2715
		2716	And even the 100% non-blocking version written using the high-level (and
		2717	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2718	higher level ("unoptimised") abstractions by a large margin, even though
		2719	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
		2720
		2721	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2722	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2723	part of the IO::Lambda distribution and were used without any changes.
		2724
1791		2725
1792	=head1 SIGNALS	2726	=head1 SIGNALS
1793		2727
1794	AnyEvent currently installs handlers for these signals:	2728	AnyEvent currently installs handlers for these signals:
1795		2729
…		…
1798	=item SIGCHLD	2732	=item SIGCHLD
1799		2733
1800	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2734	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1801	emulation for event loops that do not support them natively. Also, some	2735	emulation for event loops that do not support them natively. Also, some
1802	event loops install a similar handler.	2736	event loops install a similar handler.
		2737
		2738	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2739	AnyEvent will reset it to default, to avoid losing child exit statuses.
1803		2740
1804	=item SIGPIPE	2741	=item SIGPIPE
1805		2742
1806	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2743	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1807	when AnyEvent gets loaded.	2744	when AnyEvent gets loaded.
…		…
1819		2756
1820	=back	2757	=back
1821		2758
1822	=cut	2759	=cut
1823		2760
		2761	undef $SIG{CHLD}
		2762	if $SIG{CHLD} eq 'IGNORE';
		2763
1824	$SIG{PIPE} = sub { }	2764	$SIG{PIPE} = sub { }
1825	unless defined $SIG{PIPE};	2765	unless defined $SIG{PIPE};
1826		2766
		2767	=head1 RECOMMENDED/OPTIONAL MODULES
		2768
		2769	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2770	its built-in modules) are required to use it.
		2771
		2772	That does not mean that AnyEvent won't take advantage of some additional
		2773	modules if they are installed.
		2774
		2775	This section explains which additional modules will be used, and how they
		2776	affect AnyEvent's operation.
		2777
		2778	=over 4
		2779
		2780	=item L<Async::Interrupt>
		2781
		2782	This slightly arcane module is used to implement fast signal handling: To
		2783	my knowledge, there is no way to do completely race-free and quick
		2784	signal handling in pure perl. To ensure that signals still get
		2785	delivered, AnyEvent will start an interval timer to wake up perl (and
		2786	catch the signals) with some delay (default is 10 seconds, look for
		2787	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2788
		2789	If this module is available, then it will be used to implement signal
		2790	catching, which means that signals will not be delayed, and the event loop
		2791	will not be interrupted regularly, which is more efficient (and good for
		2792	battery life on laptops).
		2793
		2794	This affects not just the pure-perl event loop, but also other event loops
		2795	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2796
		2797	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2798	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2799	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2800	does nothing for those backends.
		2801
		2802	=item L<EV>
		2803
		2804	This module isn't really "optional", as it is simply one of the backend
		2805	event loops that AnyEvent can use. However, it is simply the best event
		2806	loop available in terms of features, speed and stability: It supports
		2807	the AnyEvent API optimally, implements all the watcher types in XS, does
		2808	automatic timer adjustments even when no monotonic clock is available,
		2809	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2810	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2811	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2812
		2813	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2814	then this module will do nothing for you.
		2815
		2816	=item L<Guard>
		2817
		2818	The guard module, when used, will be used to implement
		2819	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2820	lot less memory), but otherwise doesn't affect guard operation much. It is
		2821	purely used for performance.
		2822
		2823	=item L<JSON> and L<JSON::XS>
		2824
		2825	One of these modules is required when you want to read or write JSON data
		2826	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2827	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2828
		2829	=item L<Net::SSLeay>
		2830
		2831	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2832	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2833	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2834
		2835	=item L<Time::HiRes>
		2836
		2837	This module is part of perl since release 5.008. It will be used when the
		2838	chosen event library does not come with a timing source of its own. The
		2839	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
		2840	try to use a monotonic clock for timing stability.
		2841
		2842	=back
		2843
1827		2844
1828	=head1 FORK	2845	=head1 FORK
1829		2846
1830	Most event libraries are not fork-safe. The ones who are usually are	2847	Most event libraries are not fork-safe. The ones who are usually are
1831	because they rely on inefficient but fork-safe C<select> or C<poll>	2848	because they rely on inefficient but fork-safe C<select> or C<poll> calls
1832	calls. Only L<EV> is fully fork-aware.	2849	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2850	are usually badly thought-out hacks that are incompatible with fork in
		2851	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2852	continue event-processing in both parent and child (or both, if you know
		2853	what you are doing).
		2854
		2855	This means that, in general, you cannot fork and do event processing in
		2856	the child if the event library was initialised before the fork (which
		2857	usually happens when the first AnyEvent watcher is created, or the library
		2858	is loaded).
1833		2859
1834	If you have to fork, you must either do so I<before> creating your first	2860	If you have to fork, you must either do so I<before> creating your first
1835	watcher OR you must not use AnyEvent at all in the child.	2861	watcher OR you must not use AnyEvent at all in the child OR you must do
		2862	something completely out of the scope of AnyEvent.
		2863
		2864	The problem of doing event processing in the parent I<and> the child
		2865	is much more complicated: even for backends that I<are> fork-aware or
		2866	fork-safe, their behaviour is not usually what you want: fork clones all
		2867	watchers, that means all timers, I/O watchers etc. are active in both
		2868	parent and child, which is almost never what you want. USing C<exec>
		2869	to start worker children from some kind of manage rprocess is usually
		2870	preferred, because it is much easier and cleaner, at the expense of having
		2871	to have another binary.
1836		2872
1837		2873
1838	=head1 SECURITY CONSIDERATIONS	2874	=head1 SECURITY CONSIDERATIONS
1839		2875
1840	AnyEvent can be forced to load any event model via	2876	AnyEvent can be forced to load any event model via
…		…
1852	use AnyEvent;	2888	use AnyEvent;
1853		2889
1854	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2890	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1855	be used to probe what backend is used and gain other information (which is	2891	be used to probe what backend is used and gain other information (which is
1856	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2892	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1857	$ENV{PERL_ANYEGENT_STRICT}.	2893	$ENV{PERL_ANYEVENT_STRICT}.
		2894
		2895	Note that AnyEvent will remove I<all> environment variables starting with
		2896	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2897	enabled.
1858		2898
1859		2899
1860	=head1 BUGS	2900	=head1 BUGS
1861		2901
1862	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2902	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1863	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2903	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1864	and check wether the leaks still show up. (Perl 5.10.0 has other annoying	2904	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1865	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as	2905	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1866	pronounced).	2906	pronounced).
1867		2907
1868		2908
1869	=head1 SEE ALSO	2909	=head1 SEE ALSO
1870		2910
1871	Utility functions: L<AnyEvent::Util>.	2911	Tutorial/Introduction: L<AnyEvent::Intro>.
1872		2912
1873	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2913	FAQ: L<AnyEvent::FAQ>.
1874	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2914
		2915	Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
		2916	(simply logging).
		2917
		2918	Development/Debugging: L<AnyEvent::Strict> (stricter checking),
		2919	L<AnyEvent::Debug> (interactive shell, watcher tracing).
		2920
		2921	Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
		2922	L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
		2923	L<Qt>, L<POE>, L<FLTK>.
1875		2924
1876	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2925	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1877	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2926	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1878	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2927	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
		2928	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
1879	L<AnyEvent::Impl::POE>.	2929	L<AnyEvent::Impl::FLTK>.
1880		2930
1881	Non-blocking file handles, sockets, TCP clients and	2931	Non-blocking handles, pipes, stream sockets, TCP clients and
1882	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2932	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1883		2933
1884	Asynchronous DNS: L<AnyEvent::DNS>.	2934	Asynchronous DNS: L<AnyEvent::DNS>.
1885		2935
1886	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2936	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
1887		2937
1888	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2938	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
		2939	L<AnyEvent::HTTP>.
1889		2940
1890		2941
1891	=head1 AUTHOR	2942	=head1 AUTHOR
1892		2943
1893	Marc Lehmann <schmorp@schmorp.de>	2944	Marc Lehmann <schmorp@schmorp.de>

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