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Revision 1.249 by root, Mon Jul 20 06:00:42 2009 UTC vs.
Revision 1.365 by root, Tue Aug 16 14:47:26 2011 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - events independent of event loop implementation	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
6	event loops.	6	and POE are various supported event loops/environments.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
12	# file descriptor readable	15	# file handle or descriptor readable
13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14		17
15	# one-shot or repeating timers	18	# one-shot or repeating timers
16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
18		21
19	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
21		24
22	# POSIX signal	25	# POSIX signal
…		…
43	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
44	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
45		48
46	=head1 SUPPORT	49	=head1 SUPPORT
47		50
		51	An FAQ document is available as L<AnyEvent::FAQ>.
		52
48	There is a mailinglist for discussing all things AnyEvent, and an IRC	53	There also is a mailinglist for discussing all things AnyEvent, and an IRC
49	channel, too.	54	channel, too.
50		55
51	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software	56	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
52	Respository>, at L<http://anyevent.schmorp.de>, for more info.	57	Repository>, at L<http://anyevent.schmorp.de>, for more info.
53		58
54	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	59	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
55		60
56	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
57	nowadays. So what is different about AnyEvent?	62	nowadays. So what is different about AnyEvent?
…		…
73	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
74	model you use.	79	model you use.
75		80
76	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
77	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
78	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
79	cannot use anything else, as they are simply incompatible to everything	84	cannot use anything else, as they are simply incompatible to everything
80	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
81	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.
82		87
83	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	88	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
84	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
85	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
86	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
87	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
88	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
89	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,
90	to AnyEvent, too, so it is future-proof).	95	so it is future-proof).
91		96
92	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
93	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
94	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
95	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
96	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
97	technically possible.	102	technically possible.
98		103
99	Of course, AnyEvent comes with a big (and fully optional!) toolbox	104	Of course, AnyEvent comes with a big (and fully optional!) toolbox
100	of useful functionality, such as an asynchronous DNS resolver, 100%	105	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
106	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
107	model, you should I<not> use this module.	112	model, you should I<not> use this module.
108		113
109	=head1 DESCRIPTION	114	=head1 DESCRIPTION
110		115
111	L<AnyEvent> provides an identical interface to multiple event loops. This	116	L<AnyEvent> provides a uniform interface to various event loops. This
112	allows module authors to utilise an event loop without forcing module	117	allows module authors to use event loop functionality without forcing
113	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
114	peacefully at any one time).	119	than one event loop cannot coexist peacefully).
115		120
116	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>
117	module.	122	module.
118		123
119	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
120	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
121	following modules is already loaded: L<EV>,	126	following modules is already loaded: L<EV>, L<AnyEvent::Loop>,
122	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
123	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
124	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
125	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
126	be successfully loaded will be used. If, after this, still none could be	131	the other two are not normally tried.
127	found, AnyEvent will fall back to a pure-perl event loop, which is not
128	very efficient, but should work everywhere.
129		132
130	Because AnyEvent first checks for modules that are already loaded, loading	133	Because AnyEvent first checks for modules that are already loaded, loading
131	an event model explicitly before first using AnyEvent will likely make	134	an event model explicitly before first using AnyEvent will likely make
132	that model the default. For example:	135	that model the default. For example:
133		136
…		…
135	use AnyEvent;	138	use AnyEvent;
136		139
137	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
138		141
139	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
140	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,
141	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
142		146
143	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called C<AnyEvent::Loop>. Like
144	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
145	explicitly and enjoy the high availability of that event loop :)	149	availability of that event loop :)
146		150
147	=head1 WATCHERS	151	=head1 WATCHERS
148		152
149	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
150	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
…		…
155	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
156	is in control).	160	is in control).
157		161
158	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
159	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<<
160	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
161	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
162	widely between event loops.	166	widely between event loops.
163		167
164	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
165	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
166	to it).	170	to it).
167		171
168	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.
169		173
170	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
171	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.
172		176
173	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
174		178
175	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
176	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
177	undef $w;	181	undef $w;
178	});	182	});
…		…
180	Note that C<my $w; $w => combination. This is necessary because in Perl,	184	Note that C<my $w; $w => combination. This is necessary because in Perl,
181	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
182	declared.	186	declared.
183		187
184	=head2 I/O WATCHERS	188	=head2 I/O WATCHERS
		189
		190	$w = AnyEvent->io (
		191	fh => <filehandle_or_fileno>,
		192	poll => <"r" or "w">,
		193	cb => <callback>,
		194	);
185		195
186	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
187	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
188		198
189	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch	199	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
…		…
204		214
205	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.
206	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
207	underlying file descriptor.	217	underlying file descriptor.
208		218
209	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
210	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
211	handles.	221	handles.
212		222
213	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
214	watcher.	224	watcher.
…		…
219	undef $w;	229	undef $w;
220	});	230	});
221		231
222	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
223		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
224	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 >>
225	method with the following mandatory arguments:	243	method with the following mandatory arguments:
226		244
227	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
228	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
…		…
230		248
231	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
232	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
233	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
234		252
235	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
236	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
237	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
238	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
239	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.
240		258
241	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
242	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
243	only approximate.	261	only approximate.
244		262
245	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
246		264
247	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
265		283
266	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
267	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
268	"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
269	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
270	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.
271		289
272	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
273	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
274	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)
275	timers.	293	timers.
276		294
277	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
278	AnyEvent API.	296	AnyEvent API.
…		…
300	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
301	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
302		320
303	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
304	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
305	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
306		324
307	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
308	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
309		327
310	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>
311	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
312		330
313	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
314	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
315	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
316	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
317	after three seconds.	335	after three seconds.
318		336
…		…
338	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	356	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
339	account.	357	account.
340		358
341	=item AnyEvent->now_update	359	=item AnyEvent->now_update
342		360
343	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache	361	Some event loops (such as L<EV> or L<AnyEvent::Loop>) cache the current
344	the current time for each loop iteration (see the discussion of L<<	362	time for each loop iteration (see the discussion of L<< AnyEvent->now >>,
345	AnyEvent->now >>, above).	363	above).
346		364
347	When a callback runs for a long time (or when the process sleeps), then	365	When a callback runs for a long time (or when the process sleeps), then
348	this "current" time will differ substantially from the real time, which	366	this "current" time will differ substantially from the real time, which
349	might affect timers and time-outs.	367	might affect timers and time-outs.
350		368
351	When this is the case, you can call this method, which will update the	369	When this is the case, you can call this method, which will update the
352	event loop's idea of "current time".	370	event loop's idea of "current time".
353		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
354	Note that updating the time I<might> cause some events to be handled.	379	Note that updating the time I<might> cause some events to be handled.
355		380
356	=back	381	=back
357		382
358	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
359		386
360	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
361	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
362	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
363		390
…		…
380		407
381	Example: exit on SIGINT	408	Example: exit on SIGINT
382		409
383	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
384		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling) or
		421	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		422	latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
385	=head3 Signal Races, Delays and Workarounds	429	=head3 Signal Races, Delays and Workarounds
386		430
387	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching	431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
388	callbacks to signals in a generic way, which is a pity, as you cannot do	432	callbacks to signals in a generic way, which is a pity, as you cannot
389	race-free signal handling in perl. AnyEvent will try to do it's best, but	433	do race-free signal handling in perl, requiring C libraries for
		434	this. AnyEvent will try to do its best, which means in some cases,
390	in some cases, signals will be delayed. The maximum time a signal might	435	signals will be delayed. The maximum time a signal might be delayed is
391	be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10	436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
392	seconds). This variable can be changed only before the first signal	437	variable can be changed only before the first signal watcher is created,
393	watcher is created, and should be left alone otherwise. Higher values	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
394	will cause fewer spurious wake-ups, which is better for power and CPU	440	will cause fewer spurious wake-ups, which is better for power and CPU
		441	saving.
		442
395	saving. All these problems can be avoided by installing the optional	443	All these problems can be avoided by installing the optional
396	L<Async::Interrupt> module. This will not work with inherently broken	444	L<Async::Interrupt> module, which works with most event loops. It will not
397	event loops such as L<Event> or L<Event::Lib> (and not with L<POE>	445	work with inherently broken event loops such as L<Event> or L<Event::Lib>
398	currently, as POE does it's own workaround with one-second latency). With	446	(and not with L<POE> currently, as POE does its own workaround with
399	those, you just have to suffer the delays.	447	one-second latency). For those, you just have to suffer the delays.
400		448
401	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
402		450
		451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		452
403	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.
404		454
405	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,
406	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
407	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
408	any trace events (stopped/continued).	458	finished and an exit status is available, not on any trace events
		459	(stopped/continued).
409		460
410	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
411	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
412	callback arguments.	463	callback arguments.
413		464
…		…
431	thing in an AnyEvent program, you I<have> to create at least one	482	thing in an AnyEvent program, you I<have> to create at least one
432	watcher before you C<fork> the child (alternatively, you can call	483	watcher before you C<fork> the child (alternatively, you can call
433	C<AnyEvent::detect>).	484	C<AnyEvent::detect>).
434		485
435	As most event loops do not support waiting for child events, they will be	486	As most event loops do not support waiting for child events, they will be
436	emulated by AnyEvent in most cases, in which the latency and race problems	487	emulated by AnyEvent in most cases, in which case the latency and race
437	mentioned in the description of signal watchers apply.	488	problems mentioned in the description of signal watchers apply.
438		489
439	Example: fork a process and wait for it	490	Example: fork a process and wait for it
440		491
441	my $done = AnyEvent->condvar;	492	my $done = AnyEvent->condvar;
442		493
…		…
454	# do something else, then wait for process exit	505	# do something else, then wait for process exit
455	$done->recv;	506	$done->recv;
456		507
457	=head2 IDLE WATCHERS	508	=head2 IDLE WATCHERS
458		509
459	Sometimes there is a need to do something, but it is not so important	510	$w = AnyEvent->idle (cb => <callback>);
460	to do it instantly, but only when there is nothing better to do. This
461	"nothing better to do" is usually defined to be "no other events need
462	attention by the event loop".
463		511
464	Idle watchers ideally get invoked when the event loop has nothing	512	This will repeatedly invoke the callback after the process becomes idle,
465	better to do, just before it would block the process to wait for new	513	until either the watcher is destroyed or new events have been detected.
466	events. Instead of blocking, the idle watcher is invoked.
467		514
468	Most event loops unfortunately do not really support idle watchers (only	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
469	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	525	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
470	will simply call the callback "from time to time".	526	will simply call the callback "from time to time".
471		527
472	Example: read lines from STDIN, but only process them when the	528	Example: read lines from STDIN, but only process them when the
473	program is otherwise idle:	529	program is otherwise idle:
…		…
489	});	545	});
490	});	546	});
491		547
492	=head2 CONDITION VARIABLES	548	=head2 CONDITION VARIABLES
493		549
		550	$cv = AnyEvent->condvar;
		551
		552	$cv->send (<list>);
		553	my @res = $cv->recv;
		554
494	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
495	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
496	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
497		558
498	AnyEvent is slightly different: it expects somebody else to run the event	559	AnyEvent is slightly different: it expects somebody else to run the event
499	loop and 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).
500		561
501	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
502	because they represent a condition that must become true.	563	they represent a condition that must become true.
503		564
504	Now is probably a good time to look at the examples further below.	565	Now is probably a good time to look at the examples further below.
505		566
506	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
507	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
…		…
512	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
513	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
514	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<<
515	->send >> method).	576	->send >> method).
516		577
517	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
518	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:
519	in time where multiple outstanding events have been processed. And yet	580
520	another way to call them is transactions - each condition variable can be	581	=over 4
521	used to represent a transaction, which finishes at some point and delivers	582
522	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
523		601
524	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
525	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,
526	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
527	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
…		…
540		618
541	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
542	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
543	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
544	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
545	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
546		624
547	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
548	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
549	for the send to occur.	627	for the send to occur.
550		628
551	Example: wait for a timer.	629	Example: wait for a timer.
552		630
553	# wait till the result is ready	631	# condition: "wait till the timer is fired"
554	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
555		633
556	# do something such as adding a timer	634	# create the timer - we could wait for, say
557	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
558	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
559	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
560	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
561	after => 1,	639	after => 1,
562	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
563	);	641	);
564		642
565	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
566	# calls -<send	644	# calls ->send
567	$result_ready->recv;	645	$timer_fired->recv;
568		646
569	Example: wait for a timer, but take advantage of the fact that condition	647	Example: wait for a timer, but take advantage of the fact that condition
570	variables are also callable directly.	648	variables are also callable directly.
571		649
572	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
…		…
615	they were 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
616	C<send>.	694	C<send>.
617		695
618	=item $cv->croak ($error)	696	=item $cv->croak ($error)
619		697
620	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
621	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
622		700
623	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
624	user/consumer. Doing it this way instead of calling C<croak> directly	702	user/consumer. Doing it this way instead of calling C<croak> directly
625	delays the error detetcion, but has the overwhelmign advantage that it	703	delays the error detection, but has the overwhelming advantage that it
626	diagnoses the error at the place where the result is expected, and not	704	diagnoses the error at the place where the result is expected, and not
627	deep in some event clalback without connection to the actual code causing	705	deep in some event callback with no connection to the actual code causing
628	the problem.	706	the problem.
629		707
630	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
631		709
632	=item $cv->end	710	=item $cv->end
…		…
635	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
636	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
637		715
638	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
639	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
640	>>, 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
641	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
642	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.
643		722
644	You can think of C<< $cv->send >> giving you an OR condition (one call	723	You can think of C<< $cv->send >> giving you an OR condition (one call
645	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND	724	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
646	condition (all C<begin> calls must be C<end>'ed before the condvar sends).	725	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
647		726
…		…
669	one call to C<begin>, so the condvar waits for all calls to C<end> before	748	one call to C<begin>, so the condvar waits for all calls to C<end> before
670	sending.	749	sending.
671		750
672	The ping example mentioned above is slightly more complicated, as the	751	The ping example mentioned above is slightly more complicated, as the
673	there are results to be passwd back, and the number of tasks that are	752	there are results to be passwd back, and the number of tasks that are
674	begung can potentially be zero:	753	begun can potentially be zero:
675		754
676	my $cv = AnyEvent->condvar;	755	my $cv = AnyEvent->condvar;
677		756
678	my %result;	757	my %result;
679	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
680		759
681	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
682	$cv->begin;	761	$cv->begin;
683	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
684	$result{$host} = ...;	763	$result{$host} = ...;
…		…
700	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
701	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
702	doesn't execute once).	781	doesn't execute once).
703		782
704	This is the general pattern when you "fan out" into multiple (but	783	This is the general pattern when you "fan out" into multiple (but
705	potentially none) subrequests: use an outer C<begin>/C<end> pair to set	784	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
706	the callback and ensure C<end> is called at least once, and then, for each	785	the callback and ensure C<end> is called at least once, and then, for each
707	subrequest you start, call C<begin> and for each subrequest you finish,	786	subrequest you start, call C<begin> and for each subrequest you finish,
708	call C<end>.	787	call C<end>.
709		788
710	=back	789	=back
…		…
717	=over 4	796	=over 4
718		797
719	=item $cv->recv	798	=item $cv->recv
720		799
721	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
722	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
723	normally.	802	normally.
724		803
725	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
726	will return immediately.	805	will return immediately.
727		806
…		…
744	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
745	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
746	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,
747	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
748		827
749	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
750	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
751	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
752	waits otherwise.	831	waits otherwise.
753		832
754	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
760		839
761	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
762	replaces it before doing so.	841	replaces it before doing so.
763		842
764	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
765	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
766	variable itself. Calling C<recv> inside the callback or at any later time	845	condition variable itself. If the condition is already true, the
767	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.
768		848
769	=back	849	=back
770		850
771	=head1 SUPPORTED EVENT LOOPS/BACKENDS	851	=head1 SUPPORTED EVENT LOOPS/BACKENDS
772		852
…		…
775	=over 4	855	=over 4
776		856
777	=item Backends that are autoprobed when no other event loop can be found.	857	=item Backends that are autoprobed when no other event loop can be found.
778		858
779	EV is the preferred backend when no other event loop seems to be in	859	EV is the preferred backend when no other event loop seems to be in
780	use. If EV is not installed, then AnyEvent will try Event, and, failing	860	use. If EV is not installed, then AnyEvent will fall back to its own
781	that, will fall back to its own pure-perl implementation, which is	861	pure-perl implementation, which is available everywhere as it comes with
782	available everywhere as it comes with AnyEvent itself.	862	AnyEvent itself.
783		863
784	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	864	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
785	AnyEvent::Impl::Event based on Event, very stable, few glitches.
786	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	865	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
787		866
788	=item Backends that are transparently being picked up when they are used.	867	=item Backends that are transparently being picked up when they are used.
789		868
790	These will be used when they are currently loaded when the first watcher	869	These will be used if they are already loaded when the first watcher
791	is created, in which case it is assumed that the application is using	870	is created, in which case it is assumed that the application is using
792	them. This means that AnyEvent will automatically pick the right backend	871	them. This means that AnyEvent will automatically pick the right backend
793	when the main program loads an event module before anything starts to	872	when the main program loads an event module before anything starts to
794	create watchers. Nothing special needs to be done by the main program.	873	create watchers. Nothing special needs to be done by the main program.
795		874
		875	AnyEvent::Impl::Event based on Event, very stable, few glitches.
796	AnyEvent::Impl::Glib based on Glib, slow but very stable.	876	AnyEvent::Impl::Glib based on Glib, slow but very stable.
797	AnyEvent::Impl::Tk based on Tk, very broken.	877	AnyEvent::Impl::Tk based on Tk, very broken.
798	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	878	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
799	AnyEvent::Impl::POE based on POE, very slow, some limitations.	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).
800		884
801	=item Backends with special needs.	885	=item Backends with special needs.
802		886
803	Qt requires the Qt::Application to be instantiated first, but will	887	Qt requires the Qt::Application to be instantiated first, but will
804	otherwise be picked up automatically. As long as the main program	888	otherwise be picked up automatically. As long as the main program
805	instantiates the application before any AnyEvent watchers are created,	889	instantiates the application before any AnyEvent watchers are created,
806	everything should just work.	890	everything should just work.
807		891
808	AnyEvent::Impl::Qt based on Qt.	892	AnyEvent::Impl::Qt based on Qt.
809		893
810	Support for IO::Async can only be partial, as it is too broken and
811	architecturally limited to even support the AnyEvent API. It also
812	is the only event loop that needs the loop to be set explicitly, so
813	it can only be used by a main program knowing about AnyEvent. See
814	L<AnyEvent::Impl::Async> for the gory details.
815
816	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
817
818	=item Event loops that are indirectly supported via other backends.	894	=item Event loops that are indirectly supported via other backends.
819		895
820	Some event loops can be supported via other modules:	896	Some event loops can be supported via other modules:
821		897
822	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.	898	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
…		…
847	Contains C<undef> until the first watcher is being created, before the	923	Contains C<undef> until the first watcher is being created, before the
848	backend has been autodetected.	924	backend has been autodetected.
849		925
850	Afterwards it contains the event model that is being used, which is the	926	Afterwards it contains the event model that is being used, which is the
851	name of the Perl class implementing the model. This class is usually one	927	name of the Perl class implementing the model. This class is usually one
852	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the	928	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
853	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it	929	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
854	will be C<urxvt::anyevent>).	930	will be C<urxvt::anyevent>).
855		931
856	=item AnyEvent::detect	932	=item AnyEvent::detect
857		933
858	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	934	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
859	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
860	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
861	runtime, and not e.g. while initialising of your module.	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).
862		942
863	If you need to do some initialisation before AnyEvent watchers are	943	If you need to do some initialisation before AnyEvent watchers are
864	created, use C<post_detect>.	944	created, use C<post_detect>.
865		945
866	=item $guard = AnyEvent::post_detect { BLOCK }	946	=item $guard = AnyEvent::post_detect { BLOCK }
867		947
868	Arranges for the code block to be executed as soon as the event model is	948	Arranges for the code block to be executed as soon as the event model is
869	autodetected (or immediately if this has already happened).	949	autodetected (or immediately if that has already happened).
870		950
871	The block will be executed I<after> the actual backend has been detected	951	The block will be executed I<after> the actual backend has been detected
872	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	952	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
873	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	953	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
874	other initialisations - see the sources of L<AnyEvent::Strict> or	954	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
878	event module detection too early, for example, L<AnyEvent::AIO> creates	958	event module detection too early, for example, L<AnyEvent::AIO> creates
879	and installs the global L<IO::AIO> watcher in a C<post_detect> block to	959	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
880	avoid autodetecting the event module at load time.	960	avoid autodetecting the event module at load time.
881		961
882	If called in scalar or list context, then it creates and returns an object	962	If called in scalar or list context, then it creates and returns an object
883	that automatically removes the callback again when it is destroyed. See	963	that automatically removes the callback again when it is destroyed (or
		964	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
884	L<Coro::BDB> for a case where this is useful.	965	a case where this is useful.
		966
		967	Example: Create a watcher for the IO::AIO module and store it in
		968	C<$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 ||= $guard;
885		982
886	=item @AnyEvent::post_detect	983	=item @AnyEvent::post_detect
887		984
888	If there are any code references in this array (you can C<push> to it	985	If there are any code references in this array (you can C<push> to it
889	before or after loading AnyEvent), then they will called directly after	986	before or after loading AnyEvent), then they will be called directly
890	the event loop has been chosen.	987	after the event loop has been chosen.
891		988
892	You should check C<$AnyEvent::MODEL> before adding to this array, though:	989	You should check C<$AnyEvent::MODEL> before adding to this array, though:
893	if it is defined then the event loop has already been detected, and the	990	if it is defined then the event loop has already been detected, and the
894	array will be ignored.	991	array will be ignored.
895		992
896	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	993	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
897	it,as it takes care of these details.	994	it, as it takes care of these details.
898		995
899	This variable is mainly useful for modules that can do something useful	996	This variable is mainly useful for modules that can do something useful
900	when AnyEvent is used and thus want to know when it is initialised, but do	997	when AnyEvent is used and thus want to know when it is initialised, but do
901	not need to even load it by default. This array provides the means to hook	998	not need to even load it by default. This array provides the means to hook
902	into AnyEvent passively, without loading it.	999	into AnyEvent passively, without loading it.
903		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	Loads AnyEvent::Log on first use and calls C<AnyEvent::Log::log> -
		1059	consequently, look at the L<AnyEvent::Log> documentation for details.
		1060
904	=back	1061	=back
905		1062
906	=head1 WHAT TO DO IN A MODULE	1063	=head1 WHAT TO DO IN A MODULE
907		1064
908	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1065	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
918	because it will stall the whole program, and the whole point of using	1075	because it will stall the whole program, and the whole point of using
919	events is to stay interactive.	1076	events is to stay interactive.
920		1077
921	It is fine, however, to call C<< ->recv >> when the user of your module	1078	It is fine, however, to call C<< ->recv >> when the user of your module
922	requests it (i.e. if you create a http request object ad have a method	1079	requests it (i.e. if you create a http request object ad have a method
923	called C<results> that returns the results, it should call C<< ->recv >>	1080	called C<results> that returns the results, it may call C<< ->recv >>
924	freely, as the user of your module knows what she is doing. always).	1081	freely, as the user of your module knows what she is doing. Always).
925		1082
926	=head1 WHAT TO DO IN THE MAIN PROGRAM	1083	=head1 WHAT TO DO IN THE MAIN PROGRAM
927		1084
928	There will always be a single main program - the only place that should	1085	There will always be a single main program - the only place that should
929	dictate which event model to use.	1086	dictate which event model to use.
930		1087
931	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1088	If the program is not event-based, it need not do anything special, even
932	do anything special (it does not need to be event-based) and let AnyEvent	1089	when it depends on a module that uses an AnyEvent. If the program itself
933	decide which implementation to chose if some module relies on it.	1090	uses AnyEvent, but does not care which event loop is used, all it needs
		1091	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1092	available loop implementation.
934		1093
935	If the main program relies on a specific event model - for example, in	1094	If the main program relies on a specific event model - for example, in
936	Gtk2 programs you have to rely on the Glib module - you should load the	1095	Gtk2 programs you have to rely on the Glib module - you should load the
937	event module before loading AnyEvent or any module that uses it: generally	1096	event module before loading AnyEvent or any module that uses it: generally
938	speaking, you should load it as early as possible. The reason is that	1097	speaking, you should load it as early as possible. The reason is that
939	modules might create watchers when they are loaded, and AnyEvent will	1098	modules might create watchers when they are loaded, and AnyEvent will
940	decide on the event model to use as soon as it creates watchers, and it	1099	decide on the event model to use as soon as it creates watchers, and it
941	might chose the wrong one unless you load the correct one yourself.	1100	might choose the wrong one unless you load the correct one yourself.
942		1101
943	You can chose to use a pure-perl implementation by loading the	1102	You can chose to use a pure-perl implementation by loading the
944	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1103	C<AnyEvent::Loop> module, which gives you similar behaviour
945	everywhere, but letting AnyEvent chose the model is generally better.	1104	everywhere, but letting AnyEvent chose the model is generally better.
946		1105
947	=head2 MAINLOOP EMULATION	1106	=head2 MAINLOOP EMULATION
948		1107
949	Sometimes (often for short test scripts, or even standalone programs who	1108	Sometimes (often for short test scripts, or even standalone programs who
…		…
964	=head1 OTHER MODULES	1123	=head1 OTHER MODULES
965		1124
966	The following is a non-exhaustive list of additional modules that use	1125	The following is a non-exhaustive list of additional modules that use
967	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1126	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
968	modules and other event loops in the same program. Some of the modules	1127	modules and other event loops in the same program. Some of the modules
969	come with AnyEvent, most are available via CPAN.	1128	come as part of AnyEvent, the others are available via CPAN.
970		1129
971	=over 4	1130	=over 4
972		1131
973	=item L<AnyEvent::Util>	1132	=item L<AnyEvent::Util>
974		1133
975	Contains various utility functions that replace often-used but blocking	1134	Contains various utility functions that replace often-used blocking
976	functions such as C<inet_aton> by event-/callback-based versions.	1135	functions such as C<inet_aton> with event/callback-based versions.
977		1136
978	=item L<AnyEvent::Socket>	1137	=item L<AnyEvent::Socket>
979		1138
980	Provides various utility functions for (internet protocol) sockets,	1139	Provides various utility functions for (internet protocol) sockets,
981	addresses and name resolution. Also functions to create non-blocking tcp	1140	addresses and name resolution. Also functions to create non-blocking tcp
…		…
983		1142
984	=item L<AnyEvent::Handle>	1143	=item L<AnyEvent::Handle>
985		1144
986	Provide read and write buffers, manages watchers for reads and writes,	1145	Provide read and write buffers, manages watchers for reads and writes,
987	supports raw and formatted I/O, I/O queued and fully transparent and	1146	supports raw and formatted I/O, I/O queued and fully transparent and
988	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1147	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
989		1148
990	=item L<AnyEvent::DNS>	1149	=item L<AnyEvent::DNS>
991		1150
992	Provides rich asynchronous DNS resolver capabilities.	1151	Provides rich asynchronous DNS resolver capabilities.
993		1152
		1153	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1154
		1155	Implement event-based interfaces to the protocols of the same name (for
		1156	the curious, IGS is the International Go Server and FCP is the Freenet
		1157	Client Protocol).
		1158
		1159	=item L<AnyEvent::Handle::UDP>
		1160
		1161	Here be danger!
		1162
		1163	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1164	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1165	its use of a stream-based API with a protocol that isn't streamable, that
		1166	the only way to improve it is to delete it.
		1167
		1168	It features data corruption (but typically only under load) and general
		1169	confusion. On top, the author is not only clueless about UDP but also
		1170	fact-resistant - some gems of his understanding: "connect doesn't work
		1171	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1172	packets", "I don't need to implement proper error checking as UDP doesn't
		1173	support error checking" and so on - he doesn't even understand what's
		1174	wrong with his module when it is explained to him.
		1175
994	=item L<AnyEvent::HTTP>	1176	=item L<AnyEvent::DBI>
995		1177
996	A simple-to-use HTTP library that is capable of making a lot of concurrent	1178	Executes L<DBI> requests asynchronously in a proxy process for you,
997	HTTP requests.	1179	notifying you in an event-based way when the operation is finished.
		1180
		1181	=item L<AnyEvent::AIO>
		1182
		1183	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1184	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1185	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1186	file I/O, and much more.
998		1187
999	=item L<AnyEvent::HTTPD>	1188	=item L<AnyEvent::HTTPD>
1000		1189
1001	Provides a simple web application server framework.	1190	A simple embedded webserver.
1002		1191
1003	=item L<AnyEvent::FastPing>	1192	=item L<AnyEvent::FastPing>
1004		1193
1005	The fastest ping in the west.	1194	The fastest ping in the west.
1006
1007	=item L<AnyEvent::DBI>
1008
1009	Executes L<DBI> requests asynchronously in a proxy process.
1010
1011	=item L<AnyEvent::AIO>
1012
1013	Truly asynchronous I/O, should be in the toolbox of every event
1014	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1015	together.
1016
1017	=item L<AnyEvent::BDB>
1018
1019	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1020	L<BDB> and AnyEvent together.
1021
1022	=item L<AnyEvent::GPSD>
1023
1024	A non-blocking interface to gpsd, a daemon delivering GPS information.
1025
1026	=item L<AnyEvent::IRC>
1027
1028	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1029
1030	=item L<AnyEvent::XMPP>
1031
1032	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1033	Net::XMPP2>.
1034
1035	=item L<AnyEvent::IGS>
1036
1037	A non-blocking interface to the Internet Go Server protocol (used by
1038	L<App::IGS>).
1039
1040	=item L<Net::FCP>
1041
1042	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1043	of AnyEvent.
1044
1045	=item L<Event::ExecFlow>
1046
1047	High level API for event-based execution flow control.
1048		1195
1049	=item L<Coro>	1196	=item L<Coro>
1050		1197
1051	Has special support for AnyEvent via L<Coro::AnyEvent>.	1198	Has special support for AnyEvent via L<Coro::AnyEvent>.
1052		1199
…		…
1056		1203
1057	package AnyEvent;	1204	package AnyEvent;
1058		1205
1059	# basically a tuned-down version of common::sense	1206	# basically a tuned-down version of common::sense
1060	sub common_sense {	1207	sub common_sense {
1061	# no warnings	1208	# from common:.sense 3.4
1062	${^WARNING_BITS} ^= ${^WARNING_BITS};	1209	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1063	# use strict vars subs	1210	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1064	$^H |= 0x00000600;	1211	$^H |= 0x00000600;
1065	}	1212	}
1066		1213
1067	BEGIN { AnyEvent::common_sense }	1214	BEGIN { AnyEvent::common_sense }
1068		1215
1069	use Carp ();	1216	use Carp ();
1070		1217
1071	our $VERSION = 4.85;	1218	our $VERSION = '6.01';
1072	our $MODEL;	1219	our $MODEL;
1073		1220
1074	our $AUTOLOAD;
1075	our @ISA;	1221	our @ISA;
1076		1222
1077	our @REGISTRY;	1223	our @REGISTRY;
1078		1224
1079	our $WIN32;
1080
1081	our $VERBOSE;	1225	our $VERBOSE;
1082		1226
1083	BEGIN {	1227	BEGIN {
1084	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1228	require "AnyEvent/constants.pl";
		1229
1085	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1230	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1086		1231
1087	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1232	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1088	if ${^TAINT};	1233	if ${^TAINT};
1089		1234
1090	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1235	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
1091
1092	}	1236	}
1093		1237
1094	our $MAX_SIGNAL_LATENCY = 10;	1238	our $MAX_SIGNAL_LATENCY = 10;
1095		1239
1096	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1240	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
…		…
1100	$PROTOCOL{$_} = ++$idx	1244	$PROTOCOL{$_} = ++$idx
1101	for reverse split /\s*,\s*/,	1245	for reverse split /\s*,\s*/,
1102	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1246	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1103	}	1247	}
1104		1248
		1249	our @post_detect;
		1250
		1251	sub post_detect(&) {
		1252	my ($cb) = @_;
		1253
		1254	push @post_detect, $cb;
		1255
		1256	defined wantarray
		1257	? bless \$cb, "AnyEvent::Util::postdetect"
		1258	: ()
		1259	}
		1260
		1261	sub AnyEvent::Util::postdetect::DESTROY {
		1262	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1263	}
		1264
		1265	our $POSTPONE_W;
		1266	our @POSTPONE;
		1267
		1268	sub _postpone_exec {
		1269	undef $POSTPONE_W;
		1270
		1271	&{ shift @POSTPONE }
		1272	while @POSTPONE;
		1273	}
		1274
		1275	sub postpone(&) {
		1276	push @POSTPONE, shift;
		1277
		1278	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1279
		1280	()
		1281	}
		1282
		1283	sub log($$;@) {
		1284	require AnyEvent::Log;
		1285	# AnyEvent::Log overwrites this function
		1286	goto &log;
		1287	}
		1288
1105	my @models = (	1289	our @models = (
1106	[EV:: => AnyEvent::Impl::EV::],	1290	[EV:: => AnyEvent::Impl::EV:: , 1],
1107	[Event:: => AnyEvent::Impl::Event::],	1291	[AnyEvent::Loop:: => AnyEvent::Impl::Perl:: , 1],
1108	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
1109	# everything below here will not be autoprobed	1292	# everything below here will not (normally) be autoprobed
1110	# as the pureperl backend should work everywhere	1293	# as the pure perl backend should work everywhere
1111	# and is usually faster	1294	# and is usually faster
		1295	[Event:: => AnyEvent::Impl::Event::, 1],
1112	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1296	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1113	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1297	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1298	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1114	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1299	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1115	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1300	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1116	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1301	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1117	[Wx:: => AnyEvent::Impl::POE::],	1302	[Wx:: => AnyEvent::Impl::POE::],
1118	[Prima:: => AnyEvent::Impl::POE::],	1303	[Prima:: => AnyEvent::Impl::POE::],
1119	# IO::Async is just too broken - we would need workarounds for its	1304	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1120	# byzantine signal and broken child handling, among others.	1305	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1121	# IO::Async is rather hard to detect, as it doesn't have any	1306	[FLTK:: => AnyEvent::Impl::FLTK2::],
1122	# obvious default class.
1123	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1124	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1125	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1126	);	1307	);
1127		1308
1128	our %method = map +($_ => 1),	1309	our @isa_hook;
		1310
		1311	sub _isa_set {
		1312	my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
		1313
		1314	@{"$pkg[$_-1]::ISA"} = $pkg[$_]
		1315	for 1 .. $#pkg;
		1316
		1317	grep $_ && $_->[1], @isa_hook
		1318	and AE::_reset ();
		1319	}
		1320
		1321	# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
		1322	sub _isa_hook($$;$) {
		1323	my ($i, $pkg, $reset_ae) = @_;
		1324
		1325	$isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
		1326
		1327	_isa_set;
		1328	}
		1329
		1330	# all autoloaded methods reserve the complete glob, not just the method slot.
		1331	# due to bugs in perls method cache implementation.
1129	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1332	our @methods = qw(io timer time now now_update signal child idle condvar);
1130		1333
1131	our @post_detect;
1132
1133	sub post_detect(&) {	1334	sub detect() {
1134	my ($cb) = @_;	1335	return $MODEL if $MODEL; # some programs keep references to detect
1135		1336
1136	if ($MODEL) {	1337	local $!; # for good measure
1137	$cb->();	1338	local $SIG{__DIE__}; # we use eval
1138		1339
1139	1	1340	# free some memory
		1341	*detect = sub () { $MODEL };
		1342	# undef &func doesn't correctly update the method cache. grmbl.
		1343	# so we delete the whole glob. grmbl.
		1344	# otoh, perl doesn't let me undef an active usb, but it lets me free
		1345	# a glob with an active sub. hrm. i hope it works, but perl is
		1346	# usually buggy in this department. sigh.
		1347	delete @{"AnyEvent::"}{@methods};
		1348	undef @methods;
		1349
		1350	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1351	my $model = $1;
		1352	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1353	if (eval "require $model") {
		1354	$MODEL = $model;
		1355	AnyEvent::log 7 => "loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it."
		1356	if $VERBOSE >= 7;
1140	} else {	1357	} else {
1141	push @post_detect, $cb;	1358	AnyEvent::log warn => "unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1142		1359	}
1143	defined wantarray
1144	? bless \$cb, "AnyEvent::Util::postdetect"
1145	: ()
1146	}	1360	}
1147	}
1148		1361
1149	sub AnyEvent::Util::postdetect::DESTROY {	1362	# check for already loaded models
1150	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1151	}
1152
1153	sub detect() {
1154	unless ($MODEL) {	1363	unless ($MODEL) {
1155	local $SIG{__DIE__};	1364	for (@REGISTRY, @models) {
1156		1365	my ($package, $model) = @$_;
1157	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1366	if (${"$package\::VERSION"} > 0) {
1158	my $model = "AnyEvent::Impl::$1";
1159	if (eval "require $model") {	1367	if (eval "require $model") {
1160	$MODEL = $model;	1368	$MODEL = $model;
1161	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1369	AnyEvent::log 7 => "autodetected model '$model', using it."
1162	} else {	1370	if $VERBOSE >= 7;
1163	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1371	last;
		1372	}
1164	}	1373	}
1165	}	1374	}
1166		1375
1167	# check for already loaded models
1168	unless ($MODEL) {	1376	unless ($MODEL) {
		1377	# try to autoload a model
1169	for (@REGISTRY, @models) {	1378	for (@REGISTRY, @models) {
1170	my ($package, $model) = @$_;	1379	my ($package, $model, $autoload) = @$_;
		1380	if (
		1381	$autoload
		1382	and eval "require $package"
1171	if (${"$package\::VERSION"} > 0) {	1383	and ${"$package\::VERSION"} > 0
1172	if (eval "require $model") {	1384	and eval "require $model"
		1385	) {
1173	$MODEL = $model;	1386	$MODEL = $model;
1174	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;	1387	AnyEvent::log 7 => "autoloaded model '$model', using it."
		1388	if $VERBOSE >= 7;
1175	last;	1389	last;
1176	}
1177	}	1390	}
1178	}	1391	}
1179		1392
1180	unless ($MODEL) {
1181	# try to load a model
1182
1183	for (@REGISTRY, @models) {
1184	my ($package, $model) = @$_;
1185	if (eval "require $package"
1186	and ${"$package\::VERSION"} > 0
1187	and eval "require $model") {
1188	$MODEL = $model;
1189	warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1190	last;
1191	}
1192	}
1193
1194	$MODEL	1393	$MODEL
1195	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1394	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?";
1196	}
1197	}	1395	}
1198
1199	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1200
1201	unshift @ISA, $MODEL;
1202
1203	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1204
1205	(shift @post_detect)->() while @post_detect;
1206	}	1396	}
1207		1397
		1398	# free memory only needed for probing
		1399	undef @models;
		1400	undef @REGISTRY;
		1401
		1402	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1403
		1404	# now nuke some methods that are overridden by the backend.
		1405	# SUPER usage is not allowed in these.
		1406	for (qw(time signal child idle)) {
		1407	undef &{"AnyEvent::Base::$_"}
		1408	if defined &{"$MODEL\::$_"};
		1409	}
		1410
		1411	_isa_set;
		1412
		1413	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1414	require AnyEvent::Strict;
		1415	}
		1416
		1417	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1418	require AnyEvent::Debug;
		1419	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1420	}
		1421
		1422	if (exists $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1423	require AnyEvent::Socket;
		1424	require AnyEvent::Debug;
		1425
		1426	my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
		1427	$shell =~ s/\$\$/$$/g;
		1428
		1429	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1430	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1431	}
		1432
		1433	(shift @post_detect)->() while @post_detect;
		1434	undef @post_detect;
		1435
		1436	*post_detect = sub(&) {
		1437	shift->();
		1438
		1439	undef
		1440	};
		1441
1208	$MODEL	1442	$MODEL
1209	}	1443	}
1210		1444
1211	sub AUTOLOAD {	1445	for my $name (@methods) {
1212	(my $func = $AUTOLOAD) =~ s/.*://;	1446	*$name = sub {
1213		1447	detect;
1214	$method{$func}	1448	# we use goto because
1215	or Carp::croak "$func: not a valid method for AnyEvent objects";	1449	# a) it makes the thunk more transparent
1216		1450	# b) it allows us to delete the thunk later
1217	detect unless $MODEL;	1451	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1218		1452	};
1219	my $class = shift;
1220	$class->$func (@_);
1221	}	1453	}
1222		1454
1223	# utility function to dup a filehandle. this is used by many backends	1455	# utility function to dup a filehandle. this is used by many backends
1224	# to support binding more than one watcher per filehandle (they usually	1456	# to support binding more than one watcher per filehandle (they usually
1225	# allow only one watcher per fd, so we dup it to get a different one).	1457	# allow only one watcher per fd, so we dup it to get a different one).
…		…
1235	# we assume CLOEXEC is already set by perl in all important cases	1467	# we assume CLOEXEC is already set by perl in all important cases
1236		1468
1237	($fh2, $rw)	1469	($fh2, $rw)
1238	}	1470	}
1239		1471
		1472	=head1 SIMPLIFIED AE API
		1473
		1474	Starting with version 5.0, AnyEvent officially supports a second, much
		1475	simpler, API that is designed to reduce the calling, typing and memory
		1476	overhead by using function call syntax and a fixed number of parameters.
		1477
		1478	See the L<AE> manpage for details.
		1479
		1480	=cut
		1481
		1482	package AE;
		1483
		1484	our $VERSION = $AnyEvent::VERSION;
		1485
		1486	sub _reset() {
		1487	eval q{
		1488	# fall back to the main API by default - backends and AnyEvent::Base
		1489	# implementations can overwrite these.
		1490
		1491	sub io($$$) {
		1492	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1493	}
		1494
		1495	sub timer($$$) {
		1496	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1497	}
		1498
		1499	sub signal($$) {
		1500	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1501	}
		1502
		1503	sub child($$) {
		1504	AnyEvent->child (pid => $_[0], cb => $_[1])
		1505	}
		1506
		1507	sub idle($) {
		1508	AnyEvent->idle (cb => $_[0]);
		1509	}
		1510
		1511	sub cv(;&) {
		1512	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1513	}
		1514
		1515	sub now() {
		1516	AnyEvent->now
		1517	}
		1518
		1519	sub now_update() {
		1520	AnyEvent->now_update
		1521	}
		1522
		1523	sub time() {
		1524	AnyEvent->time
		1525	}
		1526
		1527	*postpone = \&AnyEvent::postpone;
		1528	*log = \&AnyEvent::log;
		1529	};
		1530	die if $@;
		1531	}
		1532
		1533	BEGIN { _reset }
		1534
1240	package AnyEvent::Base;	1535	package AnyEvent::Base;
1241		1536
1242	# default implementations for many methods	1537	# default implementations for many methods
1243		1538
1244	sub _time {	1539	sub time {
		1540	eval q{ # poor man's autoloading {}
1245	# probe for availability of Time::HiRes	1541	# probe for availability of Time::HiRes
1246	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1542	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1247	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1543	AnyEvent::log 8 => "AnyEvent: using Time::HiRes for sub-second timing accuracy."
		1544	if $AnyEvent::VERBOSE >= 8;
		1545	*time = sub { Time::HiRes::time () };
1248	*_time = \&Time::HiRes::time;	1546	*AE::time = \& Time::HiRes::time ;
1249	# if (eval "use POSIX (); (POSIX::times())...	1547	# if (eval "use POSIX (); (POSIX::times())...
1250	} else {	1548	} else {
1251	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1549	AnyEvent::log critical => "using built-in time(), WARNING, no sub-second resolution!";
1252	*_time = sub { time }; # epic fail	1550	*time = sub { CORE::time };
		1551	*AE::time = sub (){ CORE::time };
		1552	}
		1553
		1554	*now = \&time;
1253	}	1555	};
		1556	die if $@;
1254		1557
1255	&_time	1558	&time
1256	}	1559	}
1257		1560
1258	sub time { _time }	1561	*now = \&time;
1259	sub now { _time }
1260	sub now_update { }	1562	sub now_update { }
1261		1563
		1564	sub _poll {
		1565	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1566	}
		1567
1262	# default implementation for ->condvar	1568	# default implementation for ->condvar
		1569	# in fact, the default should not be overwritten
1263		1570
1264	sub condvar {	1571	sub condvar {
		1572	eval q{ # poor man's autoloading {}
		1573	*condvar = sub {
1265	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1574	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1575	};
		1576
		1577	*AE::cv = sub (;&) {
		1578	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1579	};
		1580	};
		1581	die if $@;
		1582
		1583	&condvar
1266	}	1584	}
1267		1585
1268	# default implementation for ->signal	1586	# default implementation for ->signal
1269		1587
1270	our $HAVE_ASYNC_INTERRUPT;	1588	our $HAVE_ASYNC_INTERRUPT;
		1589
		1590	sub _have_async_interrupt() {
		1591	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1592	&& eval "use Async::Interrupt 1.02 (); 1")
		1593	unless defined $HAVE_ASYNC_INTERRUPT;
		1594
		1595	$HAVE_ASYNC_INTERRUPT
		1596	}
		1597
1271	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1598	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1272	our (%SIG_ASY, %SIG_ASY_W);	1599	our (%SIG_ASY, %SIG_ASY_W);
1273	our ($SIG_COUNT, $SIG_TW);	1600	our ($SIG_COUNT, $SIG_TW);
1274		1601
1275	sub _signal_exec {
1276	$HAVE_ASYNC_INTERRUPT
1277	? $SIGPIPE_R->drain
1278	: sysread $SIGPIPE_R, my $dummy, 9;
1279
1280	while (%SIG_EV) {
1281	for (keys %SIG_EV) {
1282	delete $SIG_EV{$_};
1283	$_->() for values %{ $SIG_CB{$_} || {} };
1284	}
1285	}
1286	}
1287
1288	# install a dumym wakeupw atcher to reduce signal catching latency	1602	# install a dummy wakeup watcher to reduce signal catching latency
		1603	# used by Impls
1289	sub _sig_add() {	1604	sub _sig_add() {
1290	unless ($SIG_COUNT++) {	1605	unless ($SIG_COUNT++) {
1291	# try to align timer on a full-second boundary, if possible	1606	# try to align timer on a full-second boundary, if possible
1292	my $NOW = AnyEvent->now;	1607	my $NOW = AE::now;
1293		1608
1294	$SIG_TW = AnyEvent->timer (	1609	$SIG_TW = AE::timer
1295	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),	1610	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1296	interval => $MAX_SIGNAL_LATENCY,	1611	$MAX_SIGNAL_LATENCY,
1297	cb => sub { }, # just for the PERL_ASYNC_CHECK	1612	sub { } # just for the PERL_ASYNC_CHECK
1298	);	1613	;
1299	}	1614	}
1300	}	1615	}
1301		1616
1302	sub _sig_del {	1617	sub _sig_del {
1303	undef $SIG_TW	1618	undef $SIG_TW
1304	unless --$SIG_COUNT;	1619	unless --$SIG_COUNT;
1305	}	1620	}
1306		1621
		1622	our $_sig_name_init; $_sig_name_init = sub {
		1623	eval q{ # poor man's autoloading {}
		1624	undef $_sig_name_init;
		1625
		1626	if (_have_async_interrupt) {
		1627	*sig2num = \&Async::Interrupt::sig2num;
		1628	*sig2name = \&Async::Interrupt::sig2name;
		1629	} else {
		1630	require Config;
		1631
		1632	my %signame2num;
		1633	@signame2num{ split ' ', $Config::Config{sig_name} }
		1634	= split ' ', $Config::Config{sig_num};
		1635
		1636	my @signum2name;
		1637	@signum2name[values %signame2num] = keys %signame2num;
		1638
		1639	*sig2num = sub($) {
		1640	$_[0] > 0 ? shift : $signame2num{+shift}
		1641	};
		1642	*sig2name = sub ($) {
		1643	$_[0] > 0 ? $signum2name[+shift] : shift
		1644	};
		1645	}
		1646	};
		1647	die if $@;
		1648	};
		1649
		1650	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1651	sub sig2name($) { &$_sig_name_init; &sig2name }
		1652
1307	sub _signal {	1653	sub signal {
1308	my (undef, %arg) = @_;	1654	eval q{ # poor man's autoloading {}
		1655	# probe for availability of Async::Interrupt
		1656	if (_have_async_interrupt) {
		1657	AnyEvent::log 8 => "using Async::Interrupt for race-free signal handling."
		1658	if $AnyEvent::VERBOSE >= 8;
1309		1659
1310	my $signal = uc $arg{signal}	1660	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1311	or Carp::croak "required option 'signal' is missing";	1661	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1312		1662
1313	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1663	} else {
		1664	AnyEvent::log 8 => "using emulated perl signal handling with latency timer."
		1665	if $AnyEvent::VERBOSE >= 8;
1314		1666
1315	if ($HAVE_ASYNC_INTERRUPT) {	1667	if (AnyEvent::WIN32) {
1316	# async::interrupt	1668	require AnyEvent::Util;
1317		1669
1318	$SIG_ASY{$signal} ||= do {	1670	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1319	my $asy = new Async::Interrupt	1671	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1320	cb => sub { undef $SIG_EV{$signal} },	1672	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1321	signal => $signal,	1673	} else {
1322	pipe => [$SIGPIPE_R->filenos],	1674	pipe $SIGPIPE_R, $SIGPIPE_W;
		1675	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
		1676	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1677
		1678	# not strictly required, as $^F is normally 2, but let's make sure...
		1679	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1680	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1323	;	1681	}
1324	$asy->pipe_autodrain (0);
1325		1682
1326	$asy	1683	$SIGPIPE_R
		1684	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1685
		1686	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
		1687	}
		1688
		1689	*signal = $HAVE_ASYNC_INTERRUPT
		1690	? sub {
		1691	my (undef, %arg) = @_;
		1692
		1693	# async::interrupt
		1694	my $signal = sig2num $arg{signal};
		1695	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1696
		1697	$SIG_ASY{$signal} ||= new Async::Interrupt
		1698	cb => sub { undef $SIG_EV{$signal} },
		1699	signal => $signal,
		1700	pipe => [$SIGPIPE_R->filenos],
		1701	pipe_autodrain => 0,
		1702	;
		1703
		1704	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1705	}
		1706	: sub {
		1707	my (undef, %arg) = @_;
		1708
		1709	# pure perl
		1710	my $signal = sig2name $arg{signal};
		1711	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1712
		1713	$SIG{$signal} ||= sub {
		1714	local $!;
		1715	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1716	undef $SIG_EV{$signal};
		1717	};
		1718
		1719	# can't do signal processing without introducing races in pure perl,
		1720	# so limit the signal latency.
		1721	_sig_add;
		1722
		1723	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1724	}
		1725	;
		1726
		1727	*AnyEvent::Base::signal::DESTROY = sub {
		1728	my ($signal, $cb) = @{$_[0]};
		1729
		1730	_sig_del;
		1731
		1732	delete $SIG_CB{$signal}{$cb};
		1733
		1734	$HAVE_ASYNC_INTERRUPT
		1735	? delete $SIG_ASY{$signal}
		1736	: # delete doesn't work with older perls - they then
		1737	# print weird messages, or just unconditionally exit
		1738	# instead of getting the default action.
		1739	undef $SIG{$signal}
		1740	unless keys %{ $SIG_CB{$signal} };
1327	};	1741	};
1328		1742
1329	} else {	1743	*_signal_exec = sub {
1330	# pure perl	1744	$HAVE_ASYNC_INTERRUPT
		1745	? $SIGPIPE_R->drain
		1746	: sysread $SIGPIPE_R, (my $dummy), 9;
1331		1747
1332	$SIG{$signal} ||= sub {	1748	while (%SIG_EV) {
1333	local $!;	1749	for (keys %SIG_EV) {
1334	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1750	delete $SIG_EV{$_};
1335	undef $SIG_EV{$signal};	1751	&$_ for values %{ $SIG_CB{$_} || {} };
		1752	}
		1753	}
1336	};	1754	};
1337
1338	# can't do signal processing without introducing races in pure perl,
1339	# so limit the signal latency.
1340	_sig_add;
1341	}	1755	};
		1756	die if $@;
1342		1757
1343	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1344	}
1345
1346	sub signal {
1347	# probe for availability of Async::Interrupt
1348	if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1349	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1350
1351	$HAVE_ASYNC_INTERRUPT = 1;
1352	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1353	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1354
1355	} else {
1356	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1357
1358	require Fcntl;
1359
1360	if (AnyEvent::WIN32) {
1361	require AnyEvent::Util;
1362
1363	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1364	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1365	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1366	} else {
1367	pipe $SIGPIPE_R, $SIGPIPE_W;
1368	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1369	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1370
1371	# not strictly required, as $^F is normally 2, but let's make sure...
1372	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1373	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1374	}
1375
1376	$SIGPIPE_R
1377	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1378
1379	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1380	}
1381
1382	*signal = \&_signal;
1383	&signal	1758	&signal
1384	}
1385
1386	sub AnyEvent::Base::signal::DESTROY {
1387	my ($signal, $cb) = @{$_[0]};
1388
1389	_sig_del;
1390
1391	delete $SIG_CB{$signal}{$cb};
1392
1393	$HAVE_ASYNC_INTERRUPT
1394	? delete $SIG_ASY{$signal}
1395	: # delete doesn't work with older perls - they then
1396	# print weird messages, or just unconditionally exit
1397	# instead of getting the default action.
1398	undef $SIG{$signal}
1399	unless keys %{ $SIG_CB{$signal} };
1400	}	1759	}
1401		1760
1402	# default implementation for ->child	1761	# default implementation for ->child
1403		1762
1404	our %PID_CB;	1763	our %PID_CB;
1405	our $CHLD_W;	1764	our $CHLD_W;
1406	our $CHLD_DELAY_W;	1765	our $CHLD_DELAY_W;
1407	our $WNOHANG;
1408		1766
1409	sub _sigchld {	1767	# used by many Impl's
1410	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1768	sub _emit_childstatus($$) {
1411	$_->($pid, $?)	1769	my (undef, $rpid, $rstatus) = @_;
		1770
		1771	$_->($rpid, $rstatus)
1412	for values %{ $PID_CB{$pid} || {} },	1772	for values %{ $PID_CB{$rpid} || {} },
1413	values %{ $PID_CB{0} || {} };	1773	values %{ $PID_CB{0} || {} };
1414	}
1415	}	1774	}
1416		1775
1417	sub child {	1776	sub child {
		1777	eval q{ # poor man's autoloading {}
		1778	*_sigchld = sub {
		1779	my $pid;
		1780
		1781	AnyEvent->_emit_childstatus ($pid, $?)
		1782	while ($pid = waitpid -1, WNOHANG) > 0;
		1783	};
		1784
		1785	*child = sub {
1418	my (undef, %arg) = @_;	1786	my (undef, %arg) = @_;
1419		1787
1420	defined (my $pid = $arg{pid} + 0)	1788	my $pid = $arg{pid};
1421	or Carp::croak "required option 'pid' is missing";	1789	my $cb = $arg{cb};
1422		1790
1423	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1791	$PID_CB{$pid}{$cb+0} = $cb;
1424		1792
1425	# WNOHANG is almost cetrainly 1 everywhere
1426	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1427	? 1
1428	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1429
1430	unless ($CHLD_W) {	1793	unless ($CHLD_W) {
1431	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1794	$CHLD_W = AE::signal CHLD => \&_sigchld;
1432	# child could be a zombie already, so make at least one round	1795	# child could be a zombie already, so make at least one round
1433	&_sigchld;	1796	&_sigchld;
1434	}	1797	}
1435		1798
1436	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1799	bless [$pid, $cb+0], "AnyEvent::Base::child"
1437	}	1800	};
1438		1801
1439	sub AnyEvent::Base::child::DESTROY {	1802	*AnyEvent::Base::child::DESTROY = sub {
1440	my ($pid, $cb) = @{$_[0]};	1803	my ($pid, $icb) = @{$_[0]};
1441		1804
1442	delete $PID_CB{$pid}{$cb};	1805	delete $PID_CB{$pid}{$icb};
1443	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1806	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1444		1807
1445	undef $CHLD_W unless keys %PID_CB;	1808	undef $CHLD_W unless keys %PID_CB;
		1809	};
		1810	};
		1811	die if $@;
		1812
		1813	&child
1446	}	1814	}
1447		1815
1448	# idle emulation is done by simply using a timer, regardless	1816	# idle emulation is done by simply using a timer, regardless
1449	# of whether the process is idle or not, and not letting	1817	# of whether the process is idle or not, and not letting
1450	# the callback use more than 50% of the time.	1818	# the callback use more than 50% of the time.
1451	sub idle {	1819	sub idle {
		1820	eval q{ # poor man's autoloading {}
		1821	*idle = sub {
1452	my (undef, %arg) = @_;	1822	my (undef, %arg) = @_;
1453		1823
1454	my ($cb, $w, $rcb) = $arg{cb};	1824	my ($cb, $w, $rcb) = $arg{cb};
1455		1825
1456	$rcb = sub {	1826	$rcb = sub {
1457	if ($cb) {	1827	if ($cb) {
1458	$w = _time;	1828	$w = AE::time;
1459	&$cb;	1829	&$cb;
1460	$w = _time - $w;	1830	$w = AE::time - $w;
1461		1831
1462	# never use more then 50% of the time for the idle watcher,	1832	# never use more then 50% of the time for the idle watcher,
1463	# within some limits	1833	# within some limits
1464	$w = 0.0001 if $w < 0.0001;	1834	$w = 0.0001 if $w < 0.0001;
1465	$w = 5 if $w > 5;	1835	$w = 5 if $w > 5;
1466		1836
1467	$w = AnyEvent->timer (after => $w, cb => $rcb);	1837	$w = AE::timer $w, 0, $rcb;
1468	} else {	1838	} else {
1469	# clean up...	1839	# clean up...
1470	undef $w;	1840	undef $w;
1471	undef $rcb;	1841	undef $rcb;
		1842	}
		1843	};
		1844
		1845	$w = AE::timer 0.05, 0, $rcb;
		1846
		1847	bless \\$cb, "AnyEvent::Base::idle"
1472	}	1848	};
		1849
		1850	*AnyEvent::Base::idle::DESTROY = sub {
		1851	undef $${$_[0]};
		1852	};
1473	};	1853	};
		1854	die if $@;
1474		1855
1475	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1856	&idle
1476
1477	bless \\$cb, "AnyEvent::Base::idle"
1478	}
1479
1480	sub AnyEvent::Base::idle::DESTROY {
1481	undef $${$_[0]};
1482	}	1857	}
1483		1858
1484	package AnyEvent::CondVar;	1859	package AnyEvent::CondVar;
1485		1860
1486	our @ISA = AnyEvent::CondVar::Base::;	1861	our @ISA = AnyEvent::CondVar::Base::;
		1862
		1863	# only to be used for subclassing
		1864	sub new {
		1865	my $class = shift;
		1866	bless AnyEvent->condvar (@_), $class
		1867	}
1487		1868
1488	package AnyEvent::CondVar::Base;	1869	package AnyEvent::CondVar::Base;
1489		1870
1490	#use overload	1871	#use overload
1491	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1872	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
…		…
1501		1882
1502	sub _send {	1883	sub _send {
1503	# nop	1884	# nop
1504	}	1885	}
1505		1886
		1887	sub _wait {
		1888	AnyEvent->_poll until $_[0]{_ae_sent};
		1889	}
		1890
1506	sub send {	1891	sub send {
1507	my $cv = shift;	1892	my $cv = shift;
1508	$cv->{_ae_sent} = [@_];	1893	$cv->{_ae_sent} = [@_];
1509	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};	1894	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1510	$cv->_send;	1895	$cv->_send;
…		…
1517		1902
1518	sub ready {	1903	sub ready {
1519	$_[0]{_ae_sent}	1904	$_[0]{_ae_sent}
1520	}	1905	}
1521		1906
1522	sub _wait {
1523	$WAITING
1524	and !$_[0]{_ae_sent}
1525	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1526
1527	local $WAITING = 1;
1528	AnyEvent->one_event while !$_[0]{_ae_sent};
1529	}
1530
1531	sub recv {	1907	sub recv {
		1908	unless ($_[0]{_ae_sent}) {
		1909	$WAITING
		1910	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1911
		1912	local $WAITING = 1;
1532	$_[0]->_wait;	1913	$_[0]->_wait;
		1914	}
1533		1915
1534	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1916	$_[0]{_ae_croak}
1535	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1917	and Carp::croak $_[0]{_ae_croak};
		1918
		1919	wantarray
		1920	? @{ $_[0]{_ae_sent} }
		1921	: $_[0]{_ae_sent}[0]
1536	}	1922	}
1537		1923
1538	sub cb {	1924	sub cb {
1539	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1925	my $cv = shift;
		1926
		1927	@_
		1928	and $cv->{_ae_cb} = shift
		1929	and $cv->{_ae_sent}
		1930	and (delete $cv->{_ae_cb})->($cv);
		1931
1540	$_[0]{_ae_cb}	1932	$cv->{_ae_cb}
1541	}	1933	}
1542		1934
1543	sub begin {	1935	sub begin {
1544	++$_[0]{_ae_counter};	1936	++$_[0]{_ae_counter};
1545	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1937	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1550	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	1942	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1551	}	1943	}
1552		1944
1553	# undocumented/compatibility with pre-3.4	1945	# undocumented/compatibility with pre-3.4
1554	*broadcast = \&send;	1946	*broadcast = \&send;
1555	*wait = \&_wait;	1947	*wait = \&recv;
1556		1948
1557	=head1 ERROR AND EXCEPTION HANDLING	1949	=head1 ERROR AND EXCEPTION HANDLING
1558		1950
1559	In general, AnyEvent does not do any error handling - it relies on the	1951	In general, AnyEvent does not do any error handling - it relies on the
1560	caller to do that if required. The L<AnyEvent::Strict> module (see also	1952	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1587		1979
1588	By default, AnyEvent will be completely silent except in fatal	1980	By default, AnyEvent will be completely silent except in fatal
1589	conditions. You can set this environment variable to make AnyEvent more	1981	conditions. You can set this environment variable to make AnyEvent more
1590	talkative.	1982	talkative.
1591		1983
1592	When set to C<1> or higher, causes AnyEvent to warn about unexpected	1984	When set to C<5> or higher, causes AnyEvent to warn about unexpected
1593	conditions, such as not being able to load the event model specified by	1985	conditions, such as not being able to load the event model specified by
1594	C<PERL_ANYEVENT_MODEL>.	1986	C<PERL_ANYEVENT_MODEL>.
1595		1987
1596	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1988	When set to C<7> or higher, cause AnyEvent to report to STDERR which event
1597	model it chooses.	1989	model it chooses.
1598		1990
1599	When set to C<8> or higher, then AnyEvent will report extra information on	1991	When set to C<8> or higher, then AnyEvent will report extra information on
1600	which optional modules it loads and how it implements certain features.	1992	which optional modules it loads and how it implements certain features.
1601		1993
…		…
1607	check the arguments passed to most method calls. If it finds any problems,	1999	check the arguments passed to most method calls. If it finds any problems,
1608	it will croak.	2000	it will croak.
1609		2001
1610	In other words, enables "strict" mode.	2002	In other words, enables "strict" mode.
1611		2003
1612	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	2004	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1613	>>, it is definitely recommended to keep it off in production. Keeping	2005	>>, it is definitely recommended to keep it off in production. Keeping
1614	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	2006	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1615	can be very useful, however.	2007	can be very useful, however.
1616		2008
		2009	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		2010
		2011	If this env variable is set, then its contents will be interpreted by
		2012	C<AnyEvent::Socket::parse_hostport> (after replacing every occurance of
		2013	C<$$> by the process pid) and an C<AnyEvent::Debug::shell> is bound on
		2014	that port. The shell object is saved in C<$AnyEvent::Debug::SHELL>.
		2015
		2016	This takes place when the first watcher is created.
		2017
		2018	For example, to bind a debug shell on a unix domain socket in
		2019	F<< /tmp/debug<pid>.sock >>, you could use this:
		2020
		2021	PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
		2022
		2023	Note that creating sockets in F</tmp> is very unsafe on multiuser
		2024	systems.
		2025
		2026	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		2027
		2028	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		2029	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
		2030
1617	=item C<PERL_ANYEVENT_MODEL>	2031	=item C<PERL_ANYEVENT_MODEL>
1618		2032
1619	This can be used to specify the event model to be used by AnyEvent, before	2033	This can be used to specify the event model to be used by AnyEvent, before
1620	auto detection and -probing kicks in. It must be a string consisting	2034	auto detection and -probing kicks in.
1621	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	2035
		2036	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		2037	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1622	and the resulting module name is loaded and if the load was successful,	2038	resulting module name is loaded and - if the load was successful - used as
1623	used as event model. If it fails to load AnyEvent will proceed with	2039	event model backend. If it fails to load then AnyEvent will proceed with
1624	auto detection and -probing.	2040	auto detection and -probing.
1625		2041
1626	This functionality might change in future versions.	2042	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		2043	nothing gets prepended and the module name is used as-is (hint: C<::> at
		2044	the end of a string designates a module name and quotes it appropriately).
1627		2045
1628	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	2046	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1629	could start your program like this:	2047	could start your program like this:
1630		2048
1631	PERL_ANYEVENT_MODEL=Perl perl ...	2049	PERL_ANYEVENT_MODEL=Perl perl ...
1632		2050
1633	=item C<PERL_ANYEVENT_PROTOCOLS>	2051	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
1754	warn "read: $input\n"; # output what has been read	2172	warn "read: $input\n"; # output what has been read
1755	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2173	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1756	},	2174	},
1757	);	2175	);
1758		2176
1759	my $time_watcher; # can only be used once
1760
1761	sub new_timer {
1762	$timer = AnyEvent->timer (after => 1, cb => sub {	2177	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1763	warn "timeout\n"; # print 'timeout' about every second	2178	warn "timeout\n"; # print 'timeout' at most every second
1764	&new_timer; # and restart the time
1765	});	2179	});
1766	}
1767
1768	new_timer; # create first timer
1769		2180
1770	$cv->recv; # wait until user enters /^q/i	2181	$cv->recv; # wait until user enters /^q/i
1771		2182
1772	=head1 REAL-WORLD EXAMPLE	2183	=head1 REAL-WORLD EXAMPLE
1773		2184
…		…
1846		2257
1847	The actual code goes further and collects all errors (C<die>s, exceptions)	2258	The actual code goes further and collects all errors (C<die>s, exceptions)
1848	that occurred during request processing. The C<result> method detects	2259	that occurred during request processing. The C<result> method detects
1849	whether an exception as thrown (it is stored inside the $txn object)	2260	whether an exception as thrown (it is stored inside the $txn object)
1850	and just throws the exception, which means connection errors and other	2261	and just throws the exception, which means connection errors and other
1851	problems get reported tot he code that tries to use the result, not in a	2262	problems get reported to the code that tries to use the result, not in a
1852	random callback.	2263	random callback.
1853		2264
1854	All of this enables the following usage styles:	2265	All of this enables the following usage styles:
1855		2266
1856	1. Blocking:	2267	1. Blocking:
…		…
1904	through AnyEvent. The benchmark creates a lot of timers (with a zero	2315	through AnyEvent. The benchmark creates a lot of timers (with a zero
1905	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2316	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1906	which it is), lets them fire exactly once and destroys them again.	2317	which it is), lets them fire exactly once and destroys them again.
1907		2318
1908	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2319	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1909	distribution.	2320	distribution. It uses the L<AE> interface, which makes a real difference
		2321	for the EV and Perl backends only.
1910		2322
1911	=head3 Explanation of the columns	2323	=head3 Explanation of the columns
1912		2324
1913	I<watcher> is the number of event watchers created/destroyed. Since	2325	I<watcher> is the number of event watchers created/destroyed. Since
1914	different event models feature vastly different performances, each event	2326	different event models feature vastly different performances, each event
…		…
1935	watcher.	2347	watcher.
1936		2348
1937	=head3 Results	2349	=head3 Results
1938		2350
1939	name watchers bytes create invoke destroy comment	2351	name watchers bytes create invoke destroy comment
1940	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2352	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1941	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2353	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1942	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2354	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1943	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2355	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1944	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2356	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1945	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2357	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1946	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2358	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1947	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2359	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1948	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2360	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1949	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2361	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1950	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2362	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1951	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2363	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1952		2364
1953	=head3 Discussion	2365	=head3 Discussion
1954		2366
1955	The benchmark does I<not> measure scalability of the event loop very	2367	The benchmark does I<not> measure scalability of the event loop very
1956	well. For example, a select-based event loop (such as the pure perl one)	2368	well. For example, a select-based event loop (such as the pure perl one)
…		…
1968	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2380	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1969	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2381	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1970	cycles with POE.	2382	cycles with POE.
1971		2383
1972	C<EV> is the sole leader regarding speed and memory use, which are both	2384	C<EV> is the sole leader regarding speed and memory use, which are both
1973	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2385	maximal/minimal, respectively. When using the L<AE> API there is zero
		2386	overhead (when going through the AnyEvent API create is about 5-6 times
		2387	slower, with other times being equal, so still uses far less memory than
1974	far less memory than any other event loop and is still faster than Event	2388	any other event loop and is still faster than Event natively).
1975	natively.
1976		2389
1977	The pure perl implementation is hit in a few sweet spots (both the	2390	The pure perl implementation is hit in a few sweet spots (both the
1978	constant timeout and the use of a single fd hit optimisations in the perl	2391	constant timeout and the use of a single fd hit optimisations in the perl
1979	interpreter and the backend itself). Nevertheless this shows that it	2392	interpreter and the backend itself). Nevertheless this shows that it
1980	adds very little overhead in itself. Like any select-based backend its	2393	adds very little overhead in itself. Like any select-based backend its
…		…
2028	(even when used without AnyEvent), but most event loops have acceptable	2441	(even when used without AnyEvent), but most event loops have acceptable
2029	performance with or without AnyEvent.	2442	performance with or without AnyEvent.
2030		2443
2031	=item * The overhead AnyEvent adds is usually much smaller than the overhead of	2444	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
2032	the actual event loop, only with extremely fast event loops such as EV	2445	the actual event loop, only with extremely fast event loops such as EV
2033	adds AnyEvent significant overhead.	2446	does AnyEvent add significant overhead.
2034		2447
2035	=item * You should avoid POE like the plague if you want performance or	2448	=item * You should avoid POE like the plague if you want performance or
2036	reasonable memory usage.	2449	reasonable memory usage.
2037		2450
2038	=back	2451	=back
…		…
2054	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2467	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2055	(1%) are active. This mirrors the activity of large servers with many	2468	(1%) are active. This mirrors the activity of large servers with many
2056	connections, most of which are idle at any one point in time.	2469	connections, most of which are idle at any one point in time.
2057		2470
2058	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2471	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2059	distribution.	2472	distribution. It uses the L<AE> interface, which makes a real difference
		2473	for the EV and Perl backends only.
2060		2474
2061	=head3 Explanation of the columns	2475	=head3 Explanation of the columns
2062		2476
2063	I<sockets> is the number of sockets, and twice the number of "servers" (as	2477	I<sockets> is the number of sockets, and twice the number of "servers" (as
2064	each server has a read and write socket end).	2478	each server has a read and write socket end).
…		…
2072	a new one that moves the timeout into the future.	2486	a new one that moves the timeout into the future.
2073		2487
2074	=head3 Results	2488	=head3 Results
2075		2489
2076	name sockets create request	2490	name sockets create request
2077	EV 20000 69.01 11.16	2491	EV 20000 62.66 7.99
2078	Perl 20000 73.32 35.87	2492	Perl 20000 68.32 32.64
2079	IOAsync 20000 157.00 98.14 epoll	2493	IOAsync 20000 174.06 101.15 epoll
2080	IOAsync 20000 159.31 616.06 poll	2494	IOAsync 20000 174.67 610.84 poll
2081	Event 20000 212.62 257.32	2495	Event 20000 202.69 242.91
2082	Glib 20000 651.16 1896.30	2496	Glib 20000 557.01 1689.52
2083	POE 20000 349.67 12317.24 uses POE::Loop::Event	2497	POE 20000 341.54 12086.32 uses POE::Loop::Event
2084		2498
2085	=head3 Discussion	2499	=head3 Discussion
2086		2500
2087	This benchmark I<does> measure scalability and overall performance of the	2501	This benchmark I<does> measure scalability and overall performance of the
2088	particular event loop.	2502	particular event loop.
…		…
2214	As you can see, the AnyEvent + EV combination even beats the	2628	As you can see, the AnyEvent + EV combination even beats the
2215	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2629	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2216	backend easily beats IO::Lambda and POE.	2630	backend easily beats IO::Lambda and POE.
2217		2631
2218	And even the 100% non-blocking version written using the high-level (and	2632	And even the 100% non-blocking version written using the high-level (and
2219	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2633	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2220	large margin, even though it does all of DNS, tcp-connect and socket I/O	2634	higher level ("unoptimised") abstractions by a large margin, even though
2221	in a non-blocking way.	2635	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2222		2636
2223	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2637	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2224	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2638	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2225	part of the IO::lambda distribution and were used without any changes.	2639	part of the IO::Lambda distribution and were used without any changes.
2226		2640
2227		2641
2228	=head1 SIGNALS	2642	=head1 SIGNALS
2229		2643
2230	AnyEvent currently installs handlers for these signals:	2644	AnyEvent currently installs handlers for these signals:
…		…
2267	unless defined $SIG{PIPE};	2681	unless defined $SIG{PIPE};
2268		2682
2269	=head1 RECOMMENDED/OPTIONAL MODULES	2683	=head1 RECOMMENDED/OPTIONAL MODULES
2270		2684
2271	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2685	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2272	it's built-in modules) are required to use it.	2686	its built-in modules) are required to use it.
2273		2687
2274	That does not mean that AnyEvent won't take advantage of some additional	2688	That does not mean that AnyEvent won't take advantage of some additional
2275	modules if they are installed.	2689	modules if they are installed.
2276		2690
2277	This section epxlains which additional modules will be used, and how they	2691	This section explains which additional modules will be used, and how they
2278	affect AnyEvent's operetion.	2692	affect AnyEvent's operation.
2279		2693
2280	=over 4	2694	=over 4
2281		2695
2282	=item L<Async::Interrupt>	2696	=item L<Async::Interrupt>
2283		2697
…		…
2288	catch the signals) with some delay (default is 10 seconds, look for	2702	catch the signals) with some delay (default is 10 seconds, look for
2289	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2703	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2290		2704
2291	If this module is available, then it will be used to implement signal	2705	If this module is available, then it will be used to implement signal
2292	catching, which means that signals will not be delayed, and the event loop	2706	catching, which means that signals will not be delayed, and the event loop
2293	will not be interrupted regularly, which is more efficient (And good for	2707	will not be interrupted regularly, which is more efficient (and good for
2294	battery life on laptops).	2708	battery life on laptops).
2295		2709
2296	This affects not just the pure-perl event loop, but also other event loops	2710	This affects not just the pure-perl event loop, but also other event loops
2297	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2711	that have no signal handling on their own (e.g. Glib, Tk, Qt).
2298		2712
…		…
2310	automatic timer adjustments even when no monotonic clock is available,	2724	automatic timer adjustments even when no monotonic clock is available,
2311	can take avdantage of advanced kernel interfaces such as C<epoll> and	2725	can take avdantage of advanced kernel interfaces such as C<epoll> and
2312	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2726	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2313	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2727	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2314		2728
		2729	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2730	then this module will do nothing for you.
		2731
2315	=item L<Guard>	2732	=item L<Guard>
2316		2733
2317	The guard module, when used, will be used to implement	2734	The guard module, when used, will be used to implement
2318	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2735	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2319	lot less memory), but otherwise doesn't affect guard operation much. It is	2736	lot less memory), but otherwise doesn't affect guard operation much. It is
2320	purely used for performance.	2737	purely used for performance.
2321		2738
2322	=item L<JSON> and L<JSON::XS>	2739	=item L<JSON> and L<JSON::XS>
2323		2740
2324	This module is required when you want to read or write JSON data via	2741	One of these modules is required when you want to read or write JSON data
2325	L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2742	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2326	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.	2743	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2327
2328	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2329	installed.
2330		2744
2331	=item L<Net::SSLeay>	2745	=item L<Net::SSLeay>
2332		2746
2333	Implementing TLS/SSL in Perl is certainly interesting, but not very	2747	Implementing TLS/SSL in Perl is certainly interesting, but not very
2334	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2748	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2335	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2749	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2336		2750
2337	=item L<Time::HiRes>	2751	=item L<Time::HiRes>
2338		2752
2339	This module is part of perl since release 5.008. It will be used when the	2753	This module is part of perl since release 5.008. It will be used when the
2340	chosen event library does not come with a timing source on it's own. The	2754	chosen event library does not come with a timing source of its own. The
2341	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2755	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2342	try to use a monotonic clock for timing stability.	2756	try to use a monotonic clock for timing stability.
2343		2757
2344	=back	2758	=back
2345		2759
2346		2760
2347	=head1 FORK	2761	=head1 FORK
2348		2762
2349	Most event libraries are not fork-safe. The ones who are usually are	2763	Most event libraries are not fork-safe. The ones who are usually are
2350	because they rely on inefficient but fork-safe C<select> or C<poll>	2764	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2351	calls. Only L<EV> is fully fork-aware.	2765	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2766	are usually badly thought-out hacks that are incompatible with fork in
		2767	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2768	continue event-processing in both parent and child (or both, if you know
		2769	what you are doing).
		2770
		2771	This means that, in general, you cannot fork and do event processing in
		2772	the child if the event library was initialised before the fork (which
		2773	usually happens when the first AnyEvent watcher is created, or the library
		2774	is loaded).
2352		2775
2353	If you have to fork, you must either do so I<before> creating your first	2776	If you have to fork, you must either do so I<before> creating your first
2354	watcher OR you must not use AnyEvent at all in the child OR you must do	2777	watcher OR you must not use AnyEvent at all in the child OR you must do
2355	something completely out of the scope of AnyEvent.	2778	something completely out of the scope of AnyEvent.
		2779
		2780	The problem of doing event processing in the parent I<and> the child
		2781	is much more complicated: even for backends that I<are> fork-aware or
		2782	fork-safe, their behaviour is not usually what you want: fork clones all
		2783	watchers, that means all timers, I/O watchers etc. are active in both
		2784	parent and child, which is almost never what you want. USing C<exec>
		2785	to start worker children from some kind of manage rprocess is usually
		2786	preferred, because it is much easier and cleaner, at the expense of having
		2787	to have another binary.
2356		2788
2357		2789
2358	=head1 SECURITY CONSIDERATIONS	2790	=head1 SECURITY CONSIDERATIONS
2359		2791
2360	AnyEvent can be forced to load any event model via	2792	AnyEvent can be forced to load any event model via
…		…
2390	pronounced).	2822	pronounced).
2391		2823
2392		2824
2393	=head1 SEE ALSO	2825	=head1 SEE ALSO
2394		2826
2395	Utility functions: L<AnyEvent::Util>.	2827	Tutorial/Introduction: L<AnyEvent::Intro>.
2396		2828
2397	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2829	FAQ: L<AnyEvent::FAQ>.
2398	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2830
		2831	Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
		2832	(simply logging).
		2833
		2834	Development/Debugging: L<AnyEvent::Strict> (stricter checking),
		2835	L<AnyEvent::Debug> (interactive shell, watcher tracing).
		2836
		2837	Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
		2838	L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
		2839	L<Qt>, L<POE>, L<FLTK>.
2399		2840
2400	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2841	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2401	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2842	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2402	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2843	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2403	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.	2844	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
		2845	L<AnyEvent::Impl::FLTK>.
2404		2846
2405	Non-blocking file handles, sockets, TCP clients and	2847	Non-blocking handles, pipes, stream sockets, TCP clients and
2406	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2848	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2407		2849
2408	Asynchronous DNS: L<AnyEvent::DNS>.	2850	Asynchronous DNS: L<AnyEvent::DNS>.
2409		2851
2410	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	2852	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2411	L<Coro::Event>,
2412		2853
2413	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	2854	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2414	L<AnyEvent::HTTP>.	2855	L<AnyEvent::HTTP>.
2415		2856
2416		2857
2417	=head1 AUTHOR	2858	=head1 AUTHOR
2418		2859

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