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Revision 1.360 by root, Sat Aug 13 22:44:05 2011 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt 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
…		…
40	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
41		44
42	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
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.
		48
		49	=head1 SUPPORT
		50
		51	An FAQ document is available as L<AnyEvent::FAQ>.
		52
		53	There also is a mailinglist for discussing all things AnyEvent, and an IRC
		54	channel, too.
		55
		56	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		57	Repository>, at L<http://anyevent.schmorp.de>, for more info.
45		58
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	59	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		60
48	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
49	nowadays. So what is different about AnyEvent?	62	nowadays. So what is different about AnyEvent?
…		…
65	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
66	model you use.	79	model you use.
67		80
68	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
69	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
70	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
71	cannot use anything else, as they are simply incompatible to everything	84	cannot use anything else, as they are simply incompatible to everything
72	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
73	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.
74		87
75	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	88	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
76	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
77	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
78	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
79	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
80	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
81	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,
82	to AnyEvent, too, so it is future-proof).	95	so it is future-proof).
83		96
84	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
85	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
86	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
87	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
88	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
89	technically possible.	102	technically possible.
90		103
91	Of course, AnyEvent comes with a big (and fully optional!) toolbox	104	Of course, AnyEvent comes with a big (and fully optional!) toolbox
92	of useful functionality, such as an asynchronous DNS resolver, 100%	105	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
98	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
99	model, you should I<not> use this module.	112	model, you should I<not> use this module.
100		113
101	=head1 DESCRIPTION	114	=head1 DESCRIPTION
102		115
103	L<AnyEvent> provides an identical interface to multiple event loops. This	116	L<AnyEvent> provides a uniform interface to various event loops. This
104	allows module authors to utilise an event loop without forcing module	117	allows module authors to use event loop functionality without forcing
105	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
106	peacefully at any one time).	119	than one event loop cannot coexist peacefully).
107		120
108	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>
109	module.	122	module.
110		123
111	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
112	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
113	following modules is already loaded: L<EV>,	126	following modules is already loaded: L<EV>, L<AnyEvent::Loop>,
114	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
115	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
116	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
117	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
118	be successfully loaded will be used. If, after this, still none could be	131	the other two are not normally tried.
119	found, AnyEvent will fall back to a pure-perl event loop, which is not
120	very efficient, but should work everywhere.
121		132
122	Because AnyEvent first checks for modules that are already loaded, loading	133	Because AnyEvent first checks for modules that are already loaded, loading
123	an event model explicitly before first using AnyEvent will likely make	134	an event model explicitly before first using AnyEvent will likely make
124	that model the default. For example:	135	that model the default. For example:
125		136
…		…
127	use AnyEvent;	138	use AnyEvent;
128		139
129	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
130		141
131	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
132	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,
133	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
134		146
135	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called C<AnyEvent::Loop>. Like
136	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
137	explicitly and enjoy the high availability of that event loop :)	149	availability of that event loop :)
138		150
139	=head1 WATCHERS	151	=head1 WATCHERS
140		152
141	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
142	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
…		…
147	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
148	is in control).	160	is in control).
149		161
150	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
151	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<<
152	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
153	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
154	widely between event loops.	166	widely between event loops.
155		167
156	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
157	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
158	to it).	170	to it).
159		171
160	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.
161		173
162	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
163	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.
164		176
165	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
166		178
167	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
168	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
169	undef $w;	181	undef $w;
170	});	182	});
…		…
172	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,
173	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
174	declared.	186	declared.
175		187
176	=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	);
177		195
178	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
179	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
180		198
181	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
…		…
196		214
197	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.
198	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
199	underlying file descriptor.	217	underlying file descriptor.
200		218
201	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
202	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
203	handles.	221	handles.
204		222
205	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
206	watcher.	224	watcher.
…		…
211	undef $w;	229	undef $w;
212	});	230	});
213		231
214	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
215		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
216	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 >>
217	method with the following mandatory arguments:	243	method with the following mandatory arguments:
218		244
219	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
220	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
…		…
222		248
223	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
224	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
225	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
226		252
227	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
228	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
229	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
230	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
231	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.
232		258
233	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
234	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
235	only approximate.	261	only approximate.
236		262
237	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
238		264
239	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
257		283
258	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
259	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
260	"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
261	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
262	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.
263		289
264	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
265	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
266	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)
267	timers.	293	timers.
268		294
269	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
270	AnyEvent API.	296	AnyEvent API.
…		…
292	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
293	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
294		320
295	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
296	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
297	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
298		324
299	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
300	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
301		327
302	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>
303	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
304		330
305	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
306	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
307	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
308	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
309	after three seconds.	335	after three seconds.
310		336
…		…
330	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	356	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
331	account.	357	account.
332		358
333	=item AnyEvent->now_update	359	=item AnyEvent->now_update
334		360
335	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
336	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 >>,
337	AnyEvent->now >>, above).	363	above).
338		364
339	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
340	this "current" time will differ substantially from the real time, which	366	this "current" time will differ substantially from the real time, which
341	might affect timers and time-outs.	367	might affect timers and time-outs.
342		368
343	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
344	event loop's idea of "current time".	370	event loop's idea of "current time".
345		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
346	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.
347		380
348	=back	381	=back
349		382
350	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351		386
352	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
353	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
354	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
355		390
…		…
368		403
369	This watcher might use C<%SIG> (depending on the event loop used),	404	This watcher might use C<%SIG> (depending on the event loop used),
370	so programs overwriting those signals directly will likely not work	405	so programs overwriting those signals directly will likely not work
371	correctly.	406	correctly.
372		407
		408	Example: exit on SIGINT
		409
		410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling) or
		421	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		422	latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
		429	=head3 Signal Races, Delays and Workarounds
		430
373	Also note that many event loops (e.g. Glib, Tk, Qt, IO::Async) do not	431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
374	support attaching callbacks to signals, which is a pity, as you cannot do	432	callbacks to signals in a generic way, which is a pity, as you cannot
375	race-free signal handling in perl. AnyEvent will try to do it's best, but	433	do race-free signal handling in perl, requiring C libraries for
		434	this. AnyEvent will try to do its best, which means in some cases,
376	in some cases, signals will be delayed. The maximum time a signal might	435	signals will be delayed. The maximum time a signal might be delayed is
377	be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10	436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
378	seconds). This variable can be changed only before the first signal	437	variable can be changed only before the first signal watcher is created,
379	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
380	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
381	saving. All these problems can be avoided by installing the optional	443	All these problems can be avoided by installing the optional
382	L<Async::Interrupt> module.	444	L<Async::Interrupt> module, which works with most event loops. It will not
383		445	work with inherently broken event loops such as L<Event> or L<Event::Lib>
384	Example: exit on SIGINT	446	(and not with L<POE> currently, as POE does its own workaround with
385		447	one-second latency). For those, you just have to suffer the delays.
386	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
387		448
388	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
389		450
		451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		452
390	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.
391		454
392	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,
393	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
394	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
395	any trace events (stopped/continued).	458	finished and an exit status is available, not on any trace events
		459	(stopped/continued).
396		460
397	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
398	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
399	callback arguments.	463	callback arguments.
400		464
…		…
418	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
419	watcher before you C<fork> the child (alternatively, you can call	483	watcher before you C<fork> the child (alternatively, you can call
420	C<AnyEvent::detect>).	484	C<AnyEvent::detect>).
421		485
422	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
423	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
424	mentioned in the description of signal watchers apply.	488	problems mentioned in the description of signal watchers apply.
425		489
426	Example: fork a process and wait for it	490	Example: fork a process and wait for it
427		491
428	my $done = AnyEvent->condvar;	492	my $done = AnyEvent->condvar;
429		493
…		…
441	# do something else, then wait for process exit	505	# do something else, then wait for process exit
442	$done->recv;	506	$done->recv;
443		507
444	=head2 IDLE WATCHERS	508	=head2 IDLE WATCHERS
445		509
446	Sometimes there is a need to do something, but it is not so important	510	$w = AnyEvent->idle (cb => <callback>);
447	to do it instantly, but only when there is nothing better to do. This
448	"nothing better to do" is usually defined to be "no other events need
449	attention by the event loop".
450		511
451	Idle watchers ideally get invoked when the event loop has nothing	512	This will repeatedly invoke the callback after the process becomes idle,
452	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.
453	events. Instead of blocking, the idle watcher is invoked.
454		514
455	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
456	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
457	will simply call the callback "from time to time".	526	will simply call the callback "from time to time".
458		527
459	Example: read lines from STDIN, but only process them when the	528	Example: read lines from STDIN, but only process them when the
460	program is otherwise idle:	529	program is otherwise idle:
…		…
476	});	545	});
477	});	546	});
478		547
479	=head2 CONDITION VARIABLES	548	=head2 CONDITION VARIABLES
480		549
		550	$cv = AnyEvent->condvar;
		551
		552	$cv->send (<list>);
		553	my @res = $cv->recv;
		554
481	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
482	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
483	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
484		558
485	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
486	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).
487		561
488	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
489	because they represent a condition that must become true.	563	they represent a condition that must become true.
490		564
491	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.
492		566
493	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
494	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
…		…
499	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
500	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
501	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<<
502	->send >> method).	576	->send >> method).
503		577
504	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
505	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:
506	in time where multiple outstanding events have been processed. And yet	580
507	another way to call them is transactions - each condition variable can be	581	=over 4
508	used to represent a transaction, which finishes at some point and delivers	582
509	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
510		601
511	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
512	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,
513	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
514	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
…		…
527		618
528	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
529	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
530	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
531	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
532	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
533		624
534	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
535	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
536	for the send to occur.	627	for the send to occur.
537		628
538	Example: wait for a timer.	629	Example: wait for a timer.
539		630
540	# wait till the result is ready	631	# condition: "wait till the timer is fired"
541	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
542		633
543	# do something such as adding a timer	634	# create the timer - we could wait for, say
544	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
545	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
546	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
547	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
548	after => 1,	639	after => 1,
549	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
550	);	641	);
551		642
552	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
553	# calls -<send	644	# calls ->send
554	$result_ready->recv;	645	$timer_fired->recv;
555		646
556	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
557	variables are also callable directly.	648	variables are also callable directly.
558		649
559	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
…		…
602	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
603	C<send>.	694	C<send>.
604		695
605	=item $cv->croak ($error)	696	=item $cv->croak ($error)
606		697
607	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
608	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
609		700
610	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
611	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
612	delays the error detetcion, but has the overwhelmign advantage that it	703	delays the error detection, but has the overwhelming advantage that it
613	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
614	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
615	the problem.	706	the problem.
616		707
617	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
618		709
619	=item $cv->end	710	=item $cv->end
…		…
622	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
623	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
624		715
625	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
626	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
627	>>, 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
628	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
629	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.
630		722
631	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
632	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
633	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).
634		726
…		…
656	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
657	sending.	749	sending.
658		750
659	The ping example mentioned above is slightly more complicated, as the	751	The ping example mentioned above is slightly more complicated, as the
660	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
661	begung can potentially be zero:	753	begun can potentially be zero:
662		754
663	my $cv = AnyEvent->condvar;	755	my $cv = AnyEvent->condvar;
664		756
665	my %result;	757	my %result;
666	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
667		759
668	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
669	$cv->begin;	761	$cv->begin;
670	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
671	$result{$host} = ...;	763	$result{$host} = ...;
…		…
687	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
688	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
689	doesn't execute once).	781	doesn't execute once).
690		782
691	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
692	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
693	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
694	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,
695	call C<end>.	787	call C<end>.
696		788
697	=back	789	=back
…		…
704	=over 4	796	=over 4
705		797
706	=item $cv->recv	798	=item $cv->recv
707		799
708	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
709	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
710	normally.	802	normally.
711		803
712	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
713	will return immediately.	805	will return immediately.
714		806
…		…
731	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
732	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
733	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,
734	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
735		827
736	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
737	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
738	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
739	waits otherwise.	831	waits otherwise.
740		832
741	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
747		839
748	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
749	replaces it before doing so.	841	replaces it before doing so.
750		842
751	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
752	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
753	variable itself. Calling C<recv> inside the callback or at any later time	845	condition variable itself. If the condition is already true, the
754	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.
755		848
756	=back	849	=back
757		850
758	=head1 SUPPORTED EVENT LOOPS/BACKENDS	851	=head1 SUPPORTED EVENT LOOPS/BACKENDS
759		852
…		…
762	=over 4	855	=over 4
763		856
764	=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.
765		858
766	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
767	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
768	that, will fall back to its own pure-perl implementation, which is	861	pure-perl implementation, which is available everywhere as it comes with
769	available everywhere as it comes with AnyEvent itself.	862	AnyEvent itself.
770		863
771	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	864	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
772	AnyEvent::Impl::Event based on Event, very stable, few glitches.
773	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	865	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
774		866
775	=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.
776		868
777	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
778	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
779	them. This means that AnyEvent will automatically pick the right backend	871	them. This means that AnyEvent will automatically pick the right backend
780	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
781	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.
782		874
		875	AnyEvent::Impl::Event based on Event, very stable, few glitches.
783	AnyEvent::Impl::Glib based on Glib, slow but very stable.	876	AnyEvent::Impl::Glib based on Glib, slow but very stable.
784	AnyEvent::Impl::Tk based on Tk, very broken.	877	AnyEvent::Impl::Tk based on Tk, very broken.
785	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	878	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
786	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).
787		884
788	=item Backends with special needs.	885	=item Backends with special needs.
789		886
790	Qt requires the Qt::Application to be instantiated first, but will	887	Qt requires the Qt::Application to be instantiated first, but will
791	otherwise be picked up automatically. As long as the main program	888	otherwise be picked up automatically. As long as the main program
792	instantiates the application before any AnyEvent watchers are created,	889	instantiates the application before any AnyEvent watchers are created,
793	everything should just work.	890	everything should just work.
794		891
795	AnyEvent::Impl::Qt based on Qt.	892	AnyEvent::Impl::Qt based on Qt.
796		893
797	Support for IO::Async can only be partial, as it is too broken and
798	architecturally limited to even support the AnyEvent API. It also
799	is the only event loop that needs the loop to be set explicitly, so
800	it can only be used by a main program knowing about AnyEvent. See
801	L<AnyEvent::Impl::Async> for the gory details.
802
803	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
804
805	=item Event loops that are indirectly supported via other backends.	894	=item Event loops that are indirectly supported via other backends.
806		895
807	Some event loops can be supported via other modules:	896	Some event loops can be supported via other modules:
808		897
809	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>.
…		…
834	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
835	backend has been autodetected.	924	backend has been autodetected.
836		925
837	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
838	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
839	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
840	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
841	will be C<urxvt::anyevent>).	930	will be C<urxvt::anyevent>).
842		931
843	=item AnyEvent::detect	932	=item AnyEvent::detect
844		933
845	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	934	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
846	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
847	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
848	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).
849		942
850	If you need to do some initialisation before AnyEvent watchers are	943	If you need to do some initialisation before AnyEvent watchers are
851	created, use C<post_detect>.	944	created, use C<post_detect>.
852		945
853	=item $guard = AnyEvent::post_detect { BLOCK }	946	=item $guard = AnyEvent::post_detect { BLOCK }
854		947
855	Arranges for the code block to be executed as soon as the event model is	948	Arranges for the code block to be executed as soon as the event model is
856	autodetected (or immediately if this has already happened).	949	autodetected (or immediately if that has already happened).
857		950
858	The block will be executed I<after> the actual backend has been detected	951	The block will be executed I<after> the actual backend has been detected
859	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	952	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
860	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	953	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
861	other initialisations - see the sources of L<AnyEvent::Strict> or	954	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
865	event module detection too early, for example, L<AnyEvent::AIO> creates	958	event module detection too early, for example, L<AnyEvent::AIO> creates
866	and installs the global L<IO::AIO> watcher in a C<post_detect> block to	959	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
867	avoid autodetecting the event module at load time.	960	avoid autodetecting the event module at load time.
868		961
869	If called in scalar or list context, then it creates and returns an object	962	If called in scalar or list context, then it creates and returns an object
870	that automatically removes the callback again when it is destroyed. See	963	that automatically removes the callback again when it is destroyed (or
		964	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
871	L<Coro::BDB> for a case where this is useful.	965	a case where this is useful.
		966
		967	Example: Create a watcher for the IO::AIO module and store it in
		968	C<$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 ||= $guard;
872		982
873	=item @AnyEvent::post_detect	983	=item @AnyEvent::post_detect
874		984
875	If there are any code references in this array (you can C<push> to it	985	If there are any code references in this array (you can C<push> to it
876	before or after loading AnyEvent), then they will called directly after	986	before or after loading AnyEvent), then they will be called directly
877	the event loop has been chosen.	987	after the event loop has been chosen.
878		988
879	You should check C<$AnyEvent::MODEL> before adding to this array, though:	989	You should check C<$AnyEvent::MODEL> before adding to this array, though:
880	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
881	array will be ignored.	991	array will be ignored.
882		992
883	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	993	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
884	it,as it takes care of these details.	994	it, as it takes care of these details.
885		995
886	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
887	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
888	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
889	into AnyEvent passively, without loading it.	999	into AnyEvent passively, without loading it.
890		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
891	=back	1054	=back
892		1055
893	=head1 WHAT TO DO IN A MODULE	1056	=head1 WHAT TO DO IN A MODULE
894		1057
895	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1058	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
905	because it will stall the whole program, and the whole point of using	1068	because it will stall the whole program, and the whole point of using
906	events is to stay interactive.	1069	events is to stay interactive.
907		1070
908	It is fine, however, to call C<< ->recv >> when the user of your module	1071	It is fine, however, to call C<< ->recv >> when the user of your module
909	requests it (i.e. if you create a http request object ad have a method	1072	requests it (i.e. if you create a http request object ad have a method
910	called C<results> that returns the results, it should call C<< ->recv >>	1073	called C<results> that returns the results, it may call C<< ->recv >>
911	freely, as the user of your module knows what she is doing. always).	1074	freely, as the user of your module knows what she is doing. Always).
912		1075
913	=head1 WHAT TO DO IN THE MAIN PROGRAM	1076	=head1 WHAT TO DO IN THE MAIN PROGRAM
914		1077
915	There will always be a single main program - the only place that should	1078	There will always be a single main program - the only place that should
916	dictate which event model to use.	1079	dictate which event model to use.
917		1080
918	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1081	If the program is not event-based, it need not do anything special, even
919	do anything special (it does not need to be event-based) and let AnyEvent	1082	when it depends on a module that uses an AnyEvent. If the program itself
920	decide which implementation to chose if some module relies on it.	1083	uses AnyEvent, but does not care which event loop is used, all it needs
		1084	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1085	available loop implementation.
921		1086
922	If the main program relies on a specific event model - for example, in	1087	If the main program relies on a specific event model - for example, in
923	Gtk2 programs you have to rely on the Glib module - you should load the	1088	Gtk2 programs you have to rely on the Glib module - you should load the
924	event module before loading AnyEvent or any module that uses it: generally	1089	event module before loading AnyEvent or any module that uses it: generally
925	speaking, you should load it as early as possible. The reason is that	1090	speaking, you should load it as early as possible. The reason is that
926	modules might create watchers when they are loaded, and AnyEvent will	1091	modules might create watchers when they are loaded, and AnyEvent will
927	decide on the event model to use as soon as it creates watchers, and it	1092	decide on the event model to use as soon as it creates watchers, and it
928	might chose the wrong one unless you load the correct one yourself.	1093	might choose the wrong one unless you load the correct one yourself.
929		1094
930	You can chose to use a pure-perl implementation by loading the	1095	You can chose to use a pure-perl implementation by loading the
931	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1096	C<AnyEvent::Loop> module, which gives you similar behaviour
932	everywhere, but letting AnyEvent chose the model is generally better.	1097	everywhere, but letting AnyEvent chose the model is generally better.
933		1098
934	=head2 MAINLOOP EMULATION	1099	=head2 MAINLOOP EMULATION
935		1100
936	Sometimes (often for short test scripts, or even standalone programs who	1101	Sometimes (often for short test scripts, or even standalone programs who
…		…
951	=head1 OTHER MODULES	1116	=head1 OTHER MODULES
952		1117
953	The following is a non-exhaustive list of additional modules that use	1118	The following is a non-exhaustive list of additional modules that use
954	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1119	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
955	modules and other event loops in the same program. Some of the modules	1120	modules and other event loops in the same program. Some of the modules
956	come with AnyEvent, most are available via CPAN.	1121	come as part of AnyEvent, the others are available via CPAN.
957		1122
958	=over 4	1123	=over 4
959		1124
960	=item L<AnyEvent::Util>	1125	=item L<AnyEvent::Util>
961		1126
962	Contains various utility functions that replace often-used but blocking	1127	Contains various utility functions that replace often-used blocking
963	functions such as C<inet_aton> by event-/callback-based versions.	1128	functions such as C<inet_aton> with event/callback-based versions.
964		1129
965	=item L<AnyEvent::Socket>	1130	=item L<AnyEvent::Socket>
966		1131
967	Provides various utility functions for (internet protocol) sockets,	1132	Provides various utility functions for (internet protocol) sockets,
968	addresses and name resolution. Also functions to create non-blocking tcp	1133	addresses and name resolution. Also functions to create non-blocking tcp
…		…
970		1135
971	=item L<AnyEvent::Handle>	1136	=item L<AnyEvent::Handle>
972		1137
973	Provide read and write buffers, manages watchers for reads and writes,	1138	Provide read and write buffers, manages watchers for reads and writes,
974	supports raw and formatted I/O, I/O queued and fully transparent and	1139	supports raw and formatted I/O, I/O queued and fully transparent and
975	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1140	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
976		1141
977	=item L<AnyEvent::DNS>	1142	=item L<AnyEvent::DNS>
978		1143
979	Provides rich asynchronous DNS resolver capabilities.	1144	Provides rich asynchronous DNS resolver capabilities.
980		1145
		1146	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1147
		1148	Implement event-based interfaces to the protocols of the same name (for
		1149	the curious, IGS is the International Go Server and FCP is the Freenet
		1150	Client Protocol).
		1151
		1152	=item L<AnyEvent::Handle::UDP>
		1153
		1154	Here be danger!
		1155
		1156	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1157	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1158	its use of a stream-based API with a protocol that isn't streamable, that
		1159	the only way to improve it is to delete it.
		1160
		1161	It features data corruption (but typically only under load) and general
		1162	confusion. On top, the author is not only clueless about UDP but also
		1163	fact-resistant - some gems of his understanding: "connect doesn't work
		1164	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1165	packets", "I don't need to implement proper error checking as UDP doesn't
		1166	support error checking" and so on - he doesn't even understand what's
		1167	wrong with his module when it is explained to him.
		1168
981	=item L<AnyEvent::HTTP>	1169	=item L<AnyEvent::DBI>
982		1170
983	A simple-to-use HTTP library that is capable of making a lot of concurrent	1171	Executes L<DBI> requests asynchronously in a proxy process for you,
984	HTTP requests.	1172	notifying you in an event-based way when the operation is finished.
		1173
		1174	=item L<AnyEvent::AIO>
		1175
		1176	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1177	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1178	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1179	file I/O, and much more.
985		1180
986	=item L<AnyEvent::HTTPD>	1181	=item L<AnyEvent::HTTPD>
987		1182
988	Provides a simple web application server framework.	1183	A simple embedded webserver.
989		1184
990	=item L<AnyEvent::FastPing>	1185	=item L<AnyEvent::FastPing>
991		1186
992	The fastest ping in the west.	1187	The fastest ping in the west.
993
994	=item L<AnyEvent::DBI>
995
996	Executes L<DBI> requests asynchronously in a proxy process.
997
998	=item L<AnyEvent::AIO>
999
1000	Truly asynchronous I/O, should be in the toolbox of every event
1001	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1002	together.
1003
1004	=item L<AnyEvent::BDB>
1005
1006	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1007	L<BDB> and AnyEvent together.
1008
1009	=item L<AnyEvent::GPSD>
1010
1011	A non-blocking interface to gpsd, a daemon delivering GPS information.
1012
1013	=item L<AnyEvent::IRC>
1014
1015	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1016
1017	=item L<AnyEvent::XMPP>
1018
1019	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1020	Net::XMPP2>.
1021
1022	=item L<AnyEvent::IGS>
1023
1024	A non-blocking interface to the Internet Go Server protocol (used by
1025	L<App::IGS>).
1026
1027	=item L<Net::FCP>
1028
1029	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1030	of AnyEvent.
1031
1032	=item L<Event::ExecFlow>
1033
1034	High level API for event-based execution flow control.
1035		1188
1036	=item L<Coro>	1189	=item L<Coro>
1037		1190
1038	Has special support for AnyEvent via L<Coro::AnyEvent>.	1191	Has special support for AnyEvent via L<Coro::AnyEvent>.
1039		1192
…		…
1043		1196
1044	package AnyEvent;	1197	package AnyEvent;
1045		1198
1046	# basically a tuned-down version of common::sense	1199	# basically a tuned-down version of common::sense
1047	sub common_sense {	1200	sub common_sense {
1048	# no warnings	1201	# from common:.sense 3.4
1049	${^WARNING_BITS} ^= ${^WARNING_BITS};	1202	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1050	# use strict vars subs	1203	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1051	$^H |= 0x00000600;	1204	$^H |= 0x00000600;
1052	}	1205	}
1053		1206
1054	BEGIN { AnyEvent::common_sense }	1207	BEGIN { AnyEvent::common_sense }
1055		1208
1056	use Carp ();	1209	use Carp ();
1057		1210
1058	our $VERSION = 4.85;	1211	our $VERSION = '6.0';
1059	our $MODEL;	1212	our $MODEL;
1060		1213
1061	our $AUTOLOAD;
1062	our @ISA;	1214	our @ISA;
1063		1215
1064	our @REGISTRY;	1216	our @REGISTRY;
1065		1217
1066	our $WIN32;
1067
1068	our $VERBOSE;	1218	our $VERBOSE;
1069		1219
1070	BEGIN {	1220	BEGIN {
1071	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1221	require "AnyEvent/constants.pl";
		1222
1072	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1223	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1073		1224
1074	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1225	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1075	if ${^TAINT};	1226	if ${^TAINT};
1076		1227
1077	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1228	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
…		…
1087	$PROTOCOL{$_} = ++$idx	1238	$PROTOCOL{$_} = ++$idx
1088	for reverse split /\s*,\s*/,	1239	for reverse split /\s*,\s*/,
1089	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1240	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1090	}	1241	}
1091		1242
		1243	our @post_detect;
		1244
		1245	sub post_detect(&) {
		1246	my ($cb) = @_;
		1247
		1248	push @post_detect, $cb;
		1249
		1250	defined wantarray
		1251	? bless \$cb, "AnyEvent::Util::postdetect"
		1252	: ()
		1253	}
		1254
		1255	sub AnyEvent::Util::postdetect::DESTROY {
		1256	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1257	}
		1258
		1259	our $POSTPONE_W;
		1260	our @POSTPONE;
		1261
		1262	sub _postpone_exec {
		1263	undef $POSTPONE_W;
		1264
		1265	&{ shift @POSTPONE }
		1266	while @POSTPONE;
		1267	}
		1268
		1269	sub postpone(&) {
		1270	push @POSTPONE, shift;
		1271
		1272	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1273
		1274	()
		1275	}
		1276
1092	my @models = (	1277	our @models = (
1093	[EV:: => AnyEvent::Impl::EV::],	1278	[EV:: => AnyEvent::Impl::EV:: , 1],
1094	[Event:: => AnyEvent::Impl::Event::],	1279	[AnyEvent::Loop:: => AnyEvent::Impl::Perl:: , 1],
1095	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
1096	# everything below here will not be autoprobed	1280	# everything below here will not (normally) be autoprobed
1097	# as the pureperl backend should work everywhere	1281	# as the pure perl backend should work everywhere
1098	# and is usually faster	1282	# and is usually faster
		1283	[Event:: => AnyEvent::Impl::Event::, 1],
1099	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1284	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1100	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1285	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1286	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1101	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1287	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1102	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1288	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1103	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1289	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1104	[Wx:: => AnyEvent::Impl::POE::],	1290	[Wx:: => AnyEvent::Impl::POE::],
1105	[Prima:: => AnyEvent::Impl::POE::],	1291	[Prima:: => AnyEvent::Impl::POE::],
1106	# IO::Async is just too broken - we would need workarounds for its	1292	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1107	# byzantine signal and broken child handling, among others.	1293	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1108	# IO::Async is rather hard to detect, as it doesn't have any	1294	[FLTK:: => AnyEvent::Impl::FLTK2::],
1109	# obvious default class.
1110	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1111	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1112	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1113	);	1295	);
1114		1296
1115	our %method = map +($_ => 1),	1297	# all autoloaded methods reserve the complete glob, not just the method slot.
		1298	# due to bugs in perls method cache implementation.
1116	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1299	our @methods = qw(io timer time now now_update signal child idle condvar);
1117		1300
1118	our @post_detect;
1119
1120	sub post_detect(&) {	1301	sub detect() {
1121	my ($cb) = @_;	1302	local $!; # for good measure
		1303	local $SIG{__DIE__}; # we use eval
1122		1304
1123	if ($MODEL) {	1305	# free some memory
1124	$cb->();	1306	*detect = sub () { $MODEL };
		1307	# undef &func doesn't correctly update the method cache. grmbl.
		1308	# so we delete the whole glob. grmbl.
		1309	# otoh, perl doesn't let me undef an active usb, but it lets me free
		1310	# a glob with an active sub. hrm. i hope it works, but perl is
		1311	# usually buggy in this department. sigh.
		1312	delete @{"AnyEvent::"}{@methods};
		1313	undef @methods;
1125		1314
1126	1	1315	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1316	my $model = $1;
		1317	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1318	if (eval "require $model") {
		1319	$MODEL = $model;
		1320	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1127	} else {	1321	} else {
1128	push @post_detect, $cb;	1322	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1129		1323	}
1130	defined wantarray
1131	? bless \$cb, "AnyEvent::Util::postdetect"
1132	: ()
1133	}	1324	}
1134	}
1135		1325
1136	sub AnyEvent::Util::postdetect::DESTROY {	1326	# check for already loaded models
1137	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1138	}
1139
1140	sub detect() {
1141	unless ($MODEL) {	1327	unless ($MODEL) {
1142	local $SIG{__DIE__};	1328	for (@REGISTRY, @models) {
1143		1329	my ($package, $model) = @$_;
1144	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1330	if (${"$package\::VERSION"} > 0) {
1145	my $model = "AnyEvent::Impl::$1";
1146	if (eval "require $model") {	1331	if (eval "require $model") {
1147	$MODEL = $model;	1332	$MODEL = $model;
1148	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1333	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1149	} else {	1334	last;
1150	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1335	}
1151	}	1336	}
1152	}	1337	}
1153		1338
1154	# check for already loaded models
1155	unless ($MODEL) {	1339	unless ($MODEL) {
		1340	# try to autoload a model
1156	for (@REGISTRY, @models) {	1341	for (@REGISTRY, @models) {
1157	my ($package, $model) = @$_;	1342	my ($package, $model, $autoload) = @$_;
		1343	if (
		1344	$autoload
		1345	and eval "require $package"
1158	if (${"$package\::VERSION"} > 0) {	1346	and ${"$package\::VERSION"} > 0
1159	if (eval "require $model") {	1347	and eval "require $model"
		1348	) {
1160	$MODEL = $model;	1349	$MODEL = $model;
1161	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;	1350	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1162	last;	1351	last;
1163	}
1164	}	1352	}
1165	}	1353	}
1166		1354
1167	unless ($MODEL) {
1168	# try to load a model
1169
1170	for (@REGISTRY, @models) {
1171	my ($package, $model) = @$_;
1172	if (eval "require $package"
1173	and ${"$package\::VERSION"} > 0
1174	and eval "require $model") {
1175	$MODEL = $model;
1176	warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1177	last;
1178	}
1179	}
1180
1181	$MODEL	1355	$MODEL
1182	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1356	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?\n";
1183	}
1184	}	1357	}
1185
1186	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1187
1188	unshift @ISA, $MODEL;
1189
1190	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1191
1192	(shift @post_detect)->() while @post_detect;
1193	}	1358	}
1194		1359
		1360	# free memory only needed for probing
		1361	undef @models;
		1362	undef @REGISTRY;
		1363
		1364	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1365	unshift @ISA, $MODEL;
		1366
		1367	# now nuke some methods that are overridden by the backend.
		1368	# SUPER usage is not allowed in these.
		1369	for (qw(time signal child idle)) {
		1370	undef &{"AnyEvent::Base::$_"}
		1371	if defined &{"$MODEL\::$_"};
		1372	}
		1373
		1374	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1375	require AnyEvent::Strict;
		1376	}
		1377
		1378	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1379	require AnyEvent::Debug;
		1380	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1381	}
		1382
		1383	if (exists $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1384	require AnyEvent::Socket;
		1385	require AnyEvent::Debug;
		1386
		1387	my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
		1388	$shell =~ s/\$\$/$$/g;
		1389
		1390	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1391	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1392	}
		1393
		1394	(shift @post_detect)->() while @post_detect;
		1395	undef @post_detect;
		1396
		1397	*post_detect = sub(&) {
		1398	shift->();
		1399
		1400	undef
		1401	};
		1402
1195	$MODEL	1403	$MODEL
1196	}	1404	}
1197		1405
1198	sub AUTOLOAD {	1406	for my $name (@methods) {
1199	(my $func = $AUTOLOAD) =~ s/.*://;	1407	*$name = sub {
1200		1408	detect;
1201	$method{$func}	1409	# we use goto because
1202	or Carp::croak "$func: not a valid method for AnyEvent objects";	1410	# a) it makes the thunk more transparent
1203		1411	# b) it allows us to delete the thunk later
1204	detect unless $MODEL;	1412	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1205		1413	};
1206	my $class = shift;
1207	$class->$func (@_);
1208	}	1414	}
1209		1415
1210	# utility function to dup a filehandle. this is used by many backends	1416	# utility function to dup a filehandle. this is used by many backends
1211	# to support binding more than one watcher per filehandle (they usually	1417	# to support binding more than one watcher per filehandle (they usually
1212	# allow only one watcher per fd, so we dup it to get a different one).	1418	# allow only one watcher per fd, so we dup it to get a different one).
…		…
1222	# we assume CLOEXEC is already set by perl in all important cases	1428	# we assume CLOEXEC is already set by perl in all important cases
1223		1429
1224	($fh2, $rw)	1430	($fh2, $rw)
1225	}	1431	}
1226		1432
		1433	=head1 SIMPLIFIED AE API
		1434
		1435	Starting with version 5.0, AnyEvent officially supports a second, much
		1436	simpler, API that is designed to reduce the calling, typing and memory
		1437	overhead by using function call syntax and a fixed number of parameters.
		1438
		1439	See the L<AE> manpage for details.
		1440
		1441	=cut
		1442
		1443	package AE;
		1444
		1445	our $VERSION = $AnyEvent::VERSION;
		1446
		1447	sub _reset() {
		1448	eval q{
		1449	# fall back to the main API by default - backends and AnyEvent::Base
		1450	# implementations can overwrite these.
		1451
		1452	sub io($$$) {
		1453	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1454	}
		1455
		1456	sub timer($$$) {
		1457	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1458	}
		1459
		1460	sub signal($$) {
		1461	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1462	}
		1463
		1464	sub child($$) {
		1465	AnyEvent->child (pid => $_[0], cb => $_[1])
		1466	}
		1467
		1468	sub idle($) {
		1469	AnyEvent->idle (cb => $_[0]);
		1470	}
		1471
		1472	sub cv(;&) {
		1473	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1474	}
		1475
		1476	sub now() {
		1477	AnyEvent->now
		1478	}
		1479
		1480	sub now_update() {
		1481	AnyEvent->now_update
		1482	}
		1483
		1484	sub time() {
		1485	AnyEvent->time
		1486	}
		1487
		1488	*postpone = \&AnyEvent::postpone;
		1489	};
		1490	die if $@;
		1491	}
		1492
		1493	BEGIN { _reset }
		1494
1227	package AnyEvent::Base;	1495	package AnyEvent::Base;
1228		1496
1229	# default implementations for many methods	1497	# default implementations for many methods
1230		1498
1231	sub _time {	1499	sub time {
		1500	eval q{ # poor man's autoloading {}
1232	# probe for availability of Time::HiRes	1501	# probe for availability of Time::HiRes
1233	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1502	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1234	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1503	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1235	*_time = \&Time::HiRes::time;	1504	*AE::time = \&Time::HiRes::time;
1236	# if (eval "use POSIX (); (POSIX::times())...	1505	# if (eval "use POSIX (); (POSIX::times())...
1237	} else {	1506	} else {
1238	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1507	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1239	*_time = sub { time }; # epic fail	1508	*AE::time = sub (){ time }; # epic fail
		1509	}
		1510
		1511	*time = sub { AE::time }; # different prototypes
1240	}	1512	};
		1513	die if $@;
1241		1514
1242	&_time	1515	&time
1243	}	1516	}
1244		1517
1245	sub time { _time }	1518	*now = \&time;
1246	sub now { _time }	1519
1247	sub now_update { }	1520	sub now_update { }
1248		1521
		1522	sub _poll {
		1523	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1524	}
		1525
1249	# default implementation for ->condvar	1526	# default implementation for ->condvar
		1527	# in fact, the default should not be overwritten
1250		1528
1251	sub condvar {	1529	sub condvar {
		1530	eval q{ # poor man's autoloading {}
		1531	*condvar = sub {
1252	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1532	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1533	};
		1534
		1535	*AE::cv = sub (;&) {
		1536	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1537	};
		1538	};
		1539	die if $@;
		1540
		1541	&condvar
1253	}	1542	}
1254		1543
1255	# default implementation for ->signal	1544	# default implementation for ->signal
1256		1545
1257	our $HAVE_ASYNC_INTERRUPT;	1546	our $HAVE_ASYNC_INTERRUPT;
		1547
		1548	sub _have_async_interrupt() {
		1549	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1550	&& eval "use Async::Interrupt 1.02 (); 1")
		1551	unless defined $HAVE_ASYNC_INTERRUPT;
		1552
		1553	$HAVE_ASYNC_INTERRUPT
		1554	}
		1555
1258	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1556	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1259	our (%SIG_ASY, %SIG_ASY_W);	1557	our (%SIG_ASY, %SIG_ASY_W);
1260	our ($SIG_COUNT, $SIG_TW);	1558	our ($SIG_COUNT, $SIG_TW);
1261		1559
1262	sub _signal_exec {
1263	$HAVE_ASYNC_INTERRUPT
1264	? $SIGPIPE_R->drain
1265	: sysread $SIGPIPE_R, my $dummy, 9;
1266
1267	while (%SIG_EV) {
1268	for (keys %SIG_EV) {
1269	delete $SIG_EV{$_};
1270	$_->() for values %{ $SIG_CB{$_} || {} };
1271	}
1272	}
1273	}
1274
1275	# install a dumym wakeupw atcher to reduce signal catching latency	1560	# install a dummy wakeup watcher to reduce signal catching latency
		1561	# used by Impls
1276	sub _sig_add() {	1562	sub _sig_add() {
1277	unless ($SIG_COUNT++) {	1563	unless ($SIG_COUNT++) {
1278	# try to align timer on a full-second boundary, if possible	1564	# try to align timer on a full-second boundary, if possible
1279	my $NOW = AnyEvent->now;	1565	my $NOW = AE::now;
1280		1566
1281	$SIG_TW = AnyEvent->timer (	1567	$SIG_TW = AE::timer
1282	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),	1568	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1283	interval => $MAX_SIGNAL_LATENCY,	1569	$MAX_SIGNAL_LATENCY,
1284	cb => sub { }, # just for the PERL_ASYNC_CHECK	1570	sub { } # just for the PERL_ASYNC_CHECK
1285	);	1571	;
1286	}	1572	}
1287	}	1573	}
1288		1574
1289	sub _sig_del {	1575	sub _sig_del {
1290	undef $SIG_TW	1576	undef $SIG_TW
1291	unless --$SIG_COUNT;	1577	unless --$SIG_COUNT;
1292	}	1578	}
1293		1579
		1580	our $_sig_name_init; $_sig_name_init = sub {
		1581	eval q{ # poor man's autoloading {}
		1582	undef $_sig_name_init;
		1583
		1584	if (_have_async_interrupt) {
		1585	*sig2num = \&Async::Interrupt::sig2num;
		1586	*sig2name = \&Async::Interrupt::sig2name;
		1587	} else {
		1588	require Config;
		1589
		1590	my %signame2num;
		1591	@signame2num{ split ' ', $Config::Config{sig_name} }
		1592	= split ' ', $Config::Config{sig_num};
		1593
		1594	my @signum2name;
		1595	@signum2name[values %signame2num] = keys %signame2num;
		1596
		1597	*sig2num = sub($) {
		1598	$_[0] > 0 ? shift : $signame2num{+shift}
		1599	};
		1600	*sig2name = sub ($) {
		1601	$_[0] > 0 ? $signum2name[+shift] : shift
		1602	};
		1603	}
		1604	};
		1605	die if $@;
		1606	};
		1607
		1608	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1609	sub sig2name($) { &$_sig_name_init; &sig2name }
		1610
1294	sub _signal {	1611	sub signal {
1295	my (undef, %arg) = @_;	1612	eval q{ # poor man's autoloading {}
		1613	# probe for availability of Async::Interrupt
		1614	if (_have_async_interrupt) {
		1615	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1296		1616
1297	my $signal = uc $arg{signal}	1617	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1298	or Carp::croak "required option 'signal' is missing";	1618	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1299		1619
1300	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1620	} else {
		1621	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1301		1622
1302	if ($HAVE_ASYNC_INTERRUPT) {	1623	if (AnyEvent::WIN32) {
1303	# async::interrupt	1624	require AnyEvent::Util;
1304		1625
1305	$SIG_ASY{$signal} ||= do {	1626	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1306	my $asy = new Async::Interrupt	1627	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1307	cb => sub { undef $SIG_EV{$signal} },	1628	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1308	signal => $signal,	1629	} else {
1309	pipe => [$SIGPIPE_R->filenos],	1630	pipe $SIGPIPE_R, $SIGPIPE_W;
		1631	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
		1632	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1633
		1634	# not strictly required, as $^F is normally 2, but let's make sure...
		1635	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1636	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1310	;	1637	}
1311	$asy->pipe_autodrain (0);
1312		1638
1313	$asy	1639	$SIGPIPE_R
		1640	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1641
		1642	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
		1643	}
		1644
		1645	*signal = $HAVE_ASYNC_INTERRUPT
		1646	? sub {
		1647	my (undef, %arg) = @_;
		1648
		1649	# async::interrupt
		1650	my $signal = sig2num $arg{signal};
		1651	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1652
		1653	$SIG_ASY{$signal} ||= new Async::Interrupt
		1654	cb => sub { undef $SIG_EV{$signal} },
		1655	signal => $signal,
		1656	pipe => [$SIGPIPE_R->filenos],
		1657	pipe_autodrain => 0,
		1658	;
		1659
		1660	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1661	}
		1662	: sub {
		1663	my (undef, %arg) = @_;
		1664
		1665	# pure perl
		1666	my $signal = sig2name $arg{signal};
		1667	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1668
		1669	$SIG{$signal} ||= sub {
		1670	local $!;
		1671	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1672	undef $SIG_EV{$signal};
		1673	};
		1674
		1675	# can't do signal processing without introducing races in pure perl,
		1676	# so limit the signal latency.
		1677	_sig_add;
		1678
		1679	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1680	}
		1681	;
		1682
		1683	*AnyEvent::Base::signal::DESTROY = sub {
		1684	my ($signal, $cb) = @{$_[0]};
		1685
		1686	_sig_del;
		1687
		1688	delete $SIG_CB{$signal}{$cb};
		1689
		1690	$HAVE_ASYNC_INTERRUPT
		1691	? delete $SIG_ASY{$signal}
		1692	: # delete doesn't work with older perls - they then
		1693	# print weird messages, or just unconditionally exit
		1694	# instead of getting the default action.
		1695	undef $SIG{$signal}
		1696	unless keys %{ $SIG_CB{$signal} };
1314	};	1697	};
1315		1698
1316	} else {	1699	*_signal_exec = sub {
1317	# pure perl	1700	$HAVE_ASYNC_INTERRUPT
		1701	? $SIGPIPE_R->drain
		1702	: sysread $SIGPIPE_R, (my $dummy), 9;
1318		1703
1319	$SIG{$signal} ||= sub {	1704	while (%SIG_EV) {
1320	local $!;	1705	for (keys %SIG_EV) {
1321	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1706	delete $SIG_EV{$_};
1322	undef $SIG_EV{$signal};	1707	&$_ for values %{ $SIG_CB{$_} || {} };
		1708	}
		1709	}
1323	};	1710	};
1324
1325	# can't do signal processing without introducing races in pure perl,
1326	# so limit the signal latency.
1327	_sig_add;
1328	}	1711	};
		1712	die if $@;
1329		1713
1330	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1331	}
1332
1333	sub signal {
1334	# probe for availability of Async::Interrupt
1335	if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1336	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1337
1338	$HAVE_ASYNC_INTERRUPT = 1;
1339	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1340	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1341
1342	} else {
1343	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1344
1345	require Fcntl;
1346
1347	if (AnyEvent::WIN32) {
1348	require AnyEvent::Util;
1349
1350	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1351	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1352	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1353	} else {
1354	pipe $SIGPIPE_R, $SIGPIPE_W;
1355	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1356	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1357
1358	# not strictly required, as $^F is normally 2, but let's make sure...
1359	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1360	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1361	}
1362
1363	$SIGPIPE_R
1364	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1365
1366	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1367	}
1368
1369	*signal = \&_signal;
1370	&signal	1714	&signal
1371	}
1372
1373	sub AnyEvent::Base::signal::DESTROY {
1374	my ($signal, $cb) = @{$_[0]};
1375
1376	_sig_del;
1377
1378	delete $SIG_CB{$signal}{$cb};
1379
1380	$HAVE_ASYNC_INTERRUPT
1381	? delete $SIG_ASY{$signal}
1382	: # delete doesn't work with older perls - they then
1383	# print weird messages, or just unconditionally exit
1384	# instead of getting the default action.
1385	undef $SIG{$signal}
1386	unless keys %{ $SIG_CB{$signal} };
1387	}	1715	}
1388		1716
1389	# default implementation for ->child	1717	# default implementation for ->child
1390		1718
1391	our %PID_CB;	1719	our %PID_CB;
1392	our $CHLD_W;	1720	our $CHLD_W;
1393	our $CHLD_DELAY_W;	1721	our $CHLD_DELAY_W;
1394	our $WNOHANG;
1395		1722
1396	sub _sigchld {	1723	# used by many Impl's
1397	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1724	sub _emit_childstatus($$) {
1398	$_->($pid, $?)	1725	my (undef, $rpid, $rstatus) = @_;
		1726
		1727	$_->($rpid, $rstatus)
1399	for values %{ $PID_CB{$pid} || {} },	1728	for values %{ $PID_CB{$rpid} || {} },
1400	values %{ $PID_CB{0} || {} };	1729	values %{ $PID_CB{0} || {} };
1401	}
1402	}	1730	}
1403		1731
1404	sub child {	1732	sub child {
		1733	eval q{ # poor man's autoloading {}
		1734	*_sigchld = sub {
		1735	my $pid;
		1736
		1737	AnyEvent->_emit_childstatus ($pid, $?)
		1738	while ($pid = waitpid -1, WNOHANG) > 0;
		1739	};
		1740
		1741	*child = sub {
1405	my (undef, %arg) = @_;	1742	my (undef, %arg) = @_;
1406		1743
1407	defined (my $pid = $arg{pid} + 0)	1744	my $pid = $arg{pid};
1408	or Carp::croak "required option 'pid' is missing";	1745	my $cb = $arg{cb};
1409		1746
1410	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1747	$PID_CB{$pid}{$cb+0} = $cb;
1411		1748
1412	# WNOHANG is almost cetrainly 1 everywhere
1413	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1414	? 1
1415	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1416
1417	unless ($CHLD_W) {	1749	unless ($CHLD_W) {
1418	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1750	$CHLD_W = AE::signal CHLD => \&_sigchld;
1419	# child could be a zombie already, so make at least one round	1751	# child could be a zombie already, so make at least one round
1420	&_sigchld;	1752	&_sigchld;
1421	}	1753	}
1422		1754
1423	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1755	bless [$pid, $cb+0], "AnyEvent::Base::child"
1424	}	1756	};
1425		1757
1426	sub AnyEvent::Base::child::DESTROY {	1758	*AnyEvent::Base::child::DESTROY = sub {
1427	my ($pid, $cb) = @{$_[0]};	1759	my ($pid, $icb) = @{$_[0]};
1428		1760
1429	delete $PID_CB{$pid}{$cb};	1761	delete $PID_CB{$pid}{$icb};
1430	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1762	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1431		1763
1432	undef $CHLD_W unless keys %PID_CB;	1764	undef $CHLD_W unless keys %PID_CB;
		1765	};
		1766	};
		1767	die if $@;
		1768
		1769	&child
1433	}	1770	}
1434		1771
1435	# idle emulation is done by simply using a timer, regardless	1772	# idle emulation is done by simply using a timer, regardless
1436	# of whether the process is idle or not, and not letting	1773	# of whether the process is idle or not, and not letting
1437	# the callback use more than 50% of the time.	1774	# the callback use more than 50% of the time.
1438	sub idle {	1775	sub idle {
		1776	eval q{ # poor man's autoloading {}
		1777	*idle = sub {
1439	my (undef, %arg) = @_;	1778	my (undef, %arg) = @_;
1440		1779
1441	my ($cb, $w, $rcb) = $arg{cb};	1780	my ($cb, $w, $rcb) = $arg{cb};
1442		1781
1443	$rcb = sub {	1782	$rcb = sub {
1444	if ($cb) {	1783	if ($cb) {
1445	$w = _time;	1784	$w = AE::time;
1446	&$cb;	1785	&$cb;
1447	$w = _time - $w;	1786	$w = AE::time - $w;
1448		1787
1449	# never use more then 50% of the time for the idle watcher,	1788	# never use more then 50% of the time for the idle watcher,
1450	# within some limits	1789	# within some limits
1451	$w = 0.0001 if $w < 0.0001;	1790	$w = 0.0001 if $w < 0.0001;
1452	$w = 5 if $w > 5;	1791	$w = 5 if $w > 5;
1453		1792
1454	$w = AnyEvent->timer (after => $w, cb => $rcb);	1793	$w = AE::timer $w, 0, $rcb;
1455	} else {	1794	} else {
1456	# clean up...	1795	# clean up...
1457	undef $w;	1796	undef $w;
1458	undef $rcb;	1797	undef $rcb;
		1798	}
		1799	};
		1800
		1801	$w = AE::timer 0.05, 0, $rcb;
		1802
		1803	bless \\$cb, "AnyEvent::Base::idle"
1459	}	1804	};
		1805
		1806	*AnyEvent::Base::idle::DESTROY = sub {
		1807	undef $${$_[0]};
		1808	};
1460	};	1809	};
		1810	die if $@;
1461		1811
1462	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1812	&idle
1463
1464	bless \\$cb, "AnyEvent::Base::idle"
1465	}
1466
1467	sub AnyEvent::Base::idle::DESTROY {
1468	undef $${$_[0]};
1469	}	1813	}
1470		1814
1471	package AnyEvent::CondVar;	1815	package AnyEvent::CondVar;
1472		1816
1473	our @ISA = AnyEvent::CondVar::Base::;	1817	our @ISA = AnyEvent::CondVar::Base::;
		1818
		1819	# only to be used for subclassing
		1820	sub new {
		1821	my $class = shift;
		1822	bless AnyEvent->condvar (@_), $class
		1823	}
1474		1824
1475	package AnyEvent::CondVar::Base;	1825	package AnyEvent::CondVar::Base;
1476		1826
1477	#use overload	1827	#use overload
1478	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1828	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
…		…
1488		1838
1489	sub _send {	1839	sub _send {
1490	# nop	1840	# nop
1491	}	1841	}
1492		1842
		1843	sub _wait {
		1844	AnyEvent->_poll until $_[0]{_ae_sent};
		1845	}
		1846
1493	sub send {	1847	sub send {
1494	my $cv = shift;	1848	my $cv = shift;
1495	$cv->{_ae_sent} = [@_];	1849	$cv->{_ae_sent} = [@_];
1496	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};	1850	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1497	$cv->_send;	1851	$cv->_send;
…		…
1504		1858
1505	sub ready {	1859	sub ready {
1506	$_[0]{_ae_sent}	1860	$_[0]{_ae_sent}
1507	}	1861	}
1508		1862
1509	sub _wait {
1510	$WAITING
1511	and !$_[0]{_ae_sent}
1512	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1513
1514	local $WAITING = 1;
1515	AnyEvent->one_event while !$_[0]{_ae_sent};
1516	}
1517
1518	sub recv {	1863	sub recv {
		1864	unless ($_[0]{_ae_sent}) {
		1865	$WAITING
		1866	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1867
		1868	local $WAITING = 1;
1519	$_[0]->_wait;	1869	$_[0]->_wait;
		1870	}
1520		1871
1521	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1872	$_[0]{_ae_croak}
1522	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1873	and Carp::croak $_[0]{_ae_croak};
		1874
		1875	wantarray
		1876	? @{ $_[0]{_ae_sent} }
		1877	: $_[0]{_ae_sent}[0]
1523	}	1878	}
1524		1879
1525	sub cb {	1880	sub cb {
1526	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1881	my $cv = shift;
		1882
		1883	@_
		1884	and $cv->{_ae_cb} = shift
		1885	and $cv->{_ae_sent}
		1886	and (delete $cv->{_ae_cb})->($cv);
		1887
1527	$_[0]{_ae_cb}	1888	$cv->{_ae_cb}
1528	}	1889	}
1529		1890
1530	sub begin {	1891	sub begin {
1531	++$_[0]{_ae_counter};	1892	++$_[0]{_ae_counter};
1532	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1893	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1537	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	1898	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1538	}	1899	}
1539		1900
1540	# undocumented/compatibility with pre-3.4	1901	# undocumented/compatibility with pre-3.4
1541	*broadcast = \&send;	1902	*broadcast = \&send;
1542	*wait = \&_wait;	1903	*wait = \&recv;
1543		1904
1544	=head1 ERROR AND EXCEPTION HANDLING	1905	=head1 ERROR AND EXCEPTION HANDLING
1545		1906
1546	In general, AnyEvent does not do any error handling - it relies on the	1907	In general, AnyEvent does not do any error handling - it relies on the
1547	caller to do that if required. The L<AnyEvent::Strict> module (see also	1908	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1594	check the arguments passed to most method calls. If it finds any problems,	1955	check the arguments passed to most method calls. If it finds any problems,
1595	it will croak.	1956	it will croak.
1596		1957
1597	In other words, enables "strict" mode.	1958	In other words, enables "strict" mode.
1598		1959
1599	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	1960	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1600	>>, it is definitely recommended to keep it off in production. Keeping	1961	>>, it is definitely recommended to keep it off in production. Keeping
1601	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	1962	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1602	can be very useful, however.	1963	can be very useful, however.
1603		1964
		1965	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		1966
		1967	If this env variable is set, then its contents will be interpreted by
		1968	C<AnyEvent::Socket::parse_hostport> (after replacing every occurance of
		1969	C<$$> by the process pid) and an C<AnyEvent::Debug::shell> is bound on
		1970	that port. The shell object is saved in C<$AnyEvent::Debug::SHELL>.
		1971
		1972	This takes place when the first watcher is created.
		1973
		1974	For example, to bind a debug shell on a unix domain socket in
		1975	F<< /tmp/debug<pid>.sock >>, you could use this:
		1976
		1977	PERL_ANYEVENT_DEBUG_SHELL=unix/:/tmp/debug\$\$.sock perlprog
		1978
		1979	Note that creating sockets in F</tmp> is very unsafe on multiuser
		1980	systems.
		1981
		1982	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		1983
		1984	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		1985	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
		1986
1604	=item C<PERL_ANYEVENT_MODEL>	1987	=item C<PERL_ANYEVENT_MODEL>
1605		1988
1606	This can be used to specify the event model to be used by AnyEvent, before	1989	This can be used to specify the event model to be used by AnyEvent, before
1607	auto detection and -probing kicks in. It must be a string consisting	1990	auto detection and -probing kicks in.
1608	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1991
		1992	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		1993	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1609	and the resulting module name is loaded and if the load was successful,	1994	resulting module name is loaded and - if the load was successful - used as
1610	used as event model. If it fails to load AnyEvent will proceed with	1995	event model backend. If it fails to load then AnyEvent will proceed with
1611	auto detection and -probing.	1996	auto detection and -probing.
1612		1997
1613	This functionality might change in future versions.	1998	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		1999	nothing gets prepended and the module name is used as-is (hint: C<::> at
		2000	the end of a string designates a module name and quotes it appropriately).
1614		2001
1615	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	2002	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1616	could start your program like this:	2003	could start your program like this:
1617		2004
1618	PERL_ANYEVENT_MODEL=Perl perl ...	2005	PERL_ANYEVENT_MODEL=Perl perl ...
1619		2006
1620	=item C<PERL_ANYEVENT_PROTOCOLS>	2007	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
1741	warn "read: $input\n"; # output what has been read	2128	warn "read: $input\n"; # output what has been read
1742	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2129	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1743	},	2130	},
1744	);	2131	);
1745		2132
1746	my $time_watcher; # can only be used once
1747
1748	sub new_timer {
1749	$timer = AnyEvent->timer (after => 1, cb => sub {	2133	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1750	warn "timeout\n"; # print 'timeout' about every second	2134	warn "timeout\n"; # print 'timeout' at most every second
1751	&new_timer; # and restart the time
1752	});	2135	});
1753	}
1754
1755	new_timer; # create first timer
1756		2136
1757	$cv->recv; # wait until user enters /^q/i	2137	$cv->recv; # wait until user enters /^q/i
1758		2138
1759	=head1 REAL-WORLD EXAMPLE	2139	=head1 REAL-WORLD EXAMPLE
1760		2140
…		…
1833		2213
1834	The actual code goes further and collects all errors (C<die>s, exceptions)	2214	The actual code goes further and collects all errors (C<die>s, exceptions)
1835	that occurred during request processing. The C<result> method detects	2215	that occurred during request processing. The C<result> method detects
1836	whether an exception as thrown (it is stored inside the $txn object)	2216	whether an exception as thrown (it is stored inside the $txn object)
1837	and just throws the exception, which means connection errors and other	2217	and just throws the exception, which means connection errors and other
1838	problems get reported tot he code that tries to use the result, not in a	2218	problems get reported to the code that tries to use the result, not in a
1839	random callback.	2219	random callback.
1840		2220
1841	All of this enables the following usage styles:	2221	All of this enables the following usage styles:
1842		2222
1843	1. Blocking:	2223	1. Blocking:
…		…
1891	through AnyEvent. The benchmark creates a lot of timers (with a zero	2271	through AnyEvent. The benchmark creates a lot of timers (with a zero
1892	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2272	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1893	which it is), lets them fire exactly once and destroys them again.	2273	which it is), lets them fire exactly once and destroys them again.
1894		2274
1895	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2275	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1896	distribution.	2276	distribution. It uses the L<AE> interface, which makes a real difference
		2277	for the EV and Perl backends only.
1897		2278
1898	=head3 Explanation of the columns	2279	=head3 Explanation of the columns
1899		2280
1900	I<watcher> is the number of event watchers created/destroyed. Since	2281	I<watcher> is the number of event watchers created/destroyed. Since
1901	different event models feature vastly different performances, each event	2282	different event models feature vastly different performances, each event
…		…
1922	watcher.	2303	watcher.
1923		2304
1924	=head3 Results	2305	=head3 Results
1925		2306
1926	name watchers bytes create invoke destroy comment	2307	name watchers bytes create invoke destroy comment
1927	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2308	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1928	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2309	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1929	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2310	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1930	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2311	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1931	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2312	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1932	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2313	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1933	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2314	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1934	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2315	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1935	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2316	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1936	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2317	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1937	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2318	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1938	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2319	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1939		2320
1940	=head3 Discussion	2321	=head3 Discussion
1941		2322
1942	The benchmark does I<not> measure scalability of the event loop very	2323	The benchmark does I<not> measure scalability of the event loop very
1943	well. For example, a select-based event loop (such as the pure perl one)	2324	well. For example, a select-based event loop (such as the pure perl one)
…		…
1955	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2336	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1956	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2337	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1957	cycles with POE.	2338	cycles with POE.
1958		2339
1959	C<EV> is the sole leader regarding speed and memory use, which are both	2340	C<EV> is the sole leader regarding speed and memory use, which are both
1960	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2341	maximal/minimal, respectively. When using the L<AE> API there is zero
		2342	overhead (when going through the AnyEvent API create is about 5-6 times
		2343	slower, with other times being equal, so still uses far less memory than
1961	far less memory than any other event loop and is still faster than Event	2344	any other event loop and is still faster than Event natively).
1962	natively.
1963		2345
1964	The pure perl implementation is hit in a few sweet spots (both the	2346	The pure perl implementation is hit in a few sweet spots (both the
1965	constant timeout and the use of a single fd hit optimisations in the perl	2347	constant timeout and the use of a single fd hit optimisations in the perl
1966	interpreter and the backend itself). Nevertheless this shows that it	2348	interpreter and the backend itself). Nevertheless this shows that it
1967	adds very little overhead in itself. Like any select-based backend its	2349	adds very little overhead in itself. Like any select-based backend its
…		…
2041	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2423	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2042	(1%) are active. This mirrors the activity of large servers with many	2424	(1%) are active. This mirrors the activity of large servers with many
2043	connections, most of which are idle at any one point in time.	2425	connections, most of which are idle at any one point in time.
2044		2426
2045	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2427	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2046	distribution.	2428	distribution. It uses the L<AE> interface, which makes a real difference
		2429	for the EV and Perl backends only.
2047		2430
2048	=head3 Explanation of the columns	2431	=head3 Explanation of the columns
2049		2432
2050	I<sockets> is the number of sockets, and twice the number of "servers" (as	2433	I<sockets> is the number of sockets, and twice the number of "servers" (as
2051	each server has a read and write socket end).	2434	each server has a read and write socket end).
…		…
2059	a new one that moves the timeout into the future.	2442	a new one that moves the timeout into the future.
2060		2443
2061	=head3 Results	2444	=head3 Results
2062		2445
2063	name sockets create request	2446	name sockets create request
2064	EV 20000 69.01 11.16	2447	EV 20000 62.66 7.99
2065	Perl 20000 73.32 35.87	2448	Perl 20000 68.32 32.64
2066	IOAsync 20000 157.00 98.14 epoll	2449	IOAsync 20000 174.06 101.15 epoll
2067	IOAsync 20000 159.31 616.06 poll	2450	IOAsync 20000 174.67 610.84 poll
2068	Event 20000 212.62 257.32	2451	Event 20000 202.69 242.91
2069	Glib 20000 651.16 1896.30	2452	Glib 20000 557.01 1689.52
2070	POE 20000 349.67 12317.24 uses POE::Loop::Event	2453	POE 20000 341.54 12086.32 uses POE::Loop::Event
2071		2454
2072	=head3 Discussion	2455	=head3 Discussion
2073		2456
2074	This benchmark I<does> measure scalability and overall performance of the	2457	This benchmark I<does> measure scalability and overall performance of the
2075	particular event loop.	2458	particular event loop.
…		…
2201	As you can see, the AnyEvent + EV combination even beats the	2584	As you can see, the AnyEvent + EV combination even beats the
2202	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2585	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2203	backend easily beats IO::Lambda and POE.	2586	backend easily beats IO::Lambda and POE.
2204		2587
2205	And even the 100% non-blocking version written using the high-level (and	2588	And even the 100% non-blocking version written using the high-level (and
2206	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2589	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2207	large margin, even though it does all of DNS, tcp-connect and socket I/O	2590	higher level ("unoptimised") abstractions by a large margin, even though
2208	in a non-blocking way.	2591	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2209		2592
2210	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2593	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2211	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2594	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2212	part of the IO::lambda distribution and were used without any changes.	2595	part of the IO::Lambda distribution and were used without any changes.
2213		2596
2214		2597
2215	=head1 SIGNALS	2598	=head1 SIGNALS
2216		2599
2217	AnyEvent currently installs handlers for these signals:	2600	AnyEvent currently installs handlers for these signals:
…		…
2254	unless defined $SIG{PIPE};	2637	unless defined $SIG{PIPE};
2255		2638
2256	=head1 RECOMMENDED/OPTIONAL MODULES	2639	=head1 RECOMMENDED/OPTIONAL MODULES
2257		2640
2258	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2641	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2259	it's built-in modules) are required to use it.	2642	its built-in modules) are required to use it.
2260		2643
2261	That does not mean that AnyEvent won't take advantage of some additional	2644	That does not mean that AnyEvent won't take advantage of some additional
2262	modules if they are installed.	2645	modules if they are installed.
2263		2646
2264	This section epxlains which additional modules will be used, and how they	2647	This section explains which additional modules will be used, and how they
2265	affect AnyEvent's operetion.	2648	affect AnyEvent's operation.
2266		2649
2267	=over 4	2650	=over 4
2268		2651
2269	=item L<Async::Interrupt>	2652	=item L<Async::Interrupt>
2270		2653
2271	This slightly arcane module is used to implement fast signal handling: To	2654	This slightly arcane module is used to implement fast signal handling: To
2272	my knowledge, there is no way to do completely race-free and quick	2655	my knowledge, there is no way to do completely race-free and quick
2273	signal handling in pure perl. To ensure that signals still get	2656	signal handling in pure perl. To ensure that signals still get
2274	delivered, AnyEvent will start an interval timer to wake up perl (and	2657	delivered, AnyEvent will start an interval timer to wake up perl (and
2275	catch the signals) with soemd elay (default is 10 seconds, look for	2658	catch the signals) with some delay (default is 10 seconds, look for
2276	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2659	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2277		2660
2278	If this module is available, then it will be used to implement signal	2661	If this module is available, then it will be used to implement signal
2279	catching, which means that signals will not be delayed, and the event loop	2662	catching, which means that signals will not be delayed, and the event loop
2280	will not be interrupted regularly, which is more efficient (And good for	2663	will not be interrupted regularly, which is more efficient (and good for
2281	battery life on laptops).	2664	battery life on laptops).
2282		2665
2283	This affects not just the pure-perl event loop, but also other event loops	2666	This affects not just the pure-perl event loop, but also other event loops
2284	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2667	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2668
		2669	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2670	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2671	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2672	does nothing for those backends.
2285		2673
2286	=item L<EV>	2674	=item L<EV>
2287		2675
2288	This module isn't really "optional", as it is simply one of the backend	2676	This module isn't really "optional", as it is simply one of the backend
2289	event loops that AnyEvent can use. However, it is simply the best event	2677	event loops that AnyEvent can use. However, it is simply the best event
…		…
2292	automatic timer adjustments even when no monotonic clock is available,	2680	automatic timer adjustments even when no monotonic clock is available,
2293	can take avdantage of advanced kernel interfaces such as C<epoll> and	2681	can take avdantage of advanced kernel interfaces such as C<epoll> and
2294	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2682	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2295	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2683	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2296		2684
		2685	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2686	then this module will do nothing for you.
		2687
2297	=item L<Guard>	2688	=item L<Guard>
2298		2689
2299	The guard module, when used, will be used to implement	2690	The guard module, when used, will be used to implement
2300	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2691	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2301	lot less memory), but otherwise doesn't affect guard operation much. It is	2692	lot less memory), but otherwise doesn't affect guard operation much. It is
2302	purely used for performance.	2693	purely used for performance.
2303		2694
2304	=item L<JSON> and L<JSON::XS>	2695	=item L<JSON> and L<JSON::XS>
2305		2696
2306	This module is required when you want to read or write JSON data via	2697	One of these modules is required when you want to read or write JSON data
2307	L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2698	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2308	advantage of the ulta-high-speed L<JSON::XS> module when it is installed.	2699	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2309
2310	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2311	installed.
2312		2700
2313	=item L<Net::SSLeay>	2701	=item L<Net::SSLeay>
2314		2702
2315	Implementing TLS/SSL in Perl is certainly interesting, but not very	2703	Implementing TLS/SSL in Perl is certainly interesting, but not very
2316	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2704	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2317	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2705	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2318		2706
2319	=item L<Time::HiRes>	2707	=item L<Time::HiRes>
2320		2708
2321	This module is part of perl since release 5.008. It will be used when the	2709	This module is part of perl since release 5.008. It will be used when the
2322	chosen event library does not come with a timing source on it's own. The	2710	chosen event library does not come with a timing source of its own. The
2323	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2711	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2324	try to use a monotonic clock for timing stability.	2712	try to use a monotonic clock for timing stability.
2325		2713
2326	=back	2714	=back
2327		2715
2328		2716
2329	=head1 FORK	2717	=head1 FORK
2330		2718
2331	Most event libraries are not fork-safe. The ones who are usually are	2719	Most event libraries are not fork-safe. The ones who are usually are
2332	because they rely on inefficient but fork-safe C<select> or C<poll>	2720	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2333	calls. Only L<EV> is fully fork-aware.	2721	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2722	are usually badly thought-out hacks that are incompatible with fork in
		2723	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2724	continue event-processing in both parent and child (or both, if you know
		2725	what you are doing).
		2726
		2727	This means that, in general, you cannot fork and do event processing in
		2728	the child if the event library was initialised before the fork (which
		2729	usually happens when the first AnyEvent watcher is created, or the library
		2730	is loaded).
2334		2731
2335	If you have to fork, you must either do so I<before> creating your first	2732	If you have to fork, you must either do so I<before> creating your first
2336	watcher OR you must not use AnyEvent at all in the child OR you must do	2733	watcher OR you must not use AnyEvent at all in the child OR you must do
2337	something completely out of the scope of AnyEvent.	2734	something completely out of the scope of AnyEvent.
		2735
		2736	The problem of doing event processing in the parent I<and> the child
		2737	is much more complicated: even for backends that I<are> fork-aware or
		2738	fork-safe, their behaviour is not usually what you want: fork clones all
		2739	watchers, that means all timers, I/O watchers etc. are active in both
		2740	parent and child, which is almost never what you want. USing C<exec>
		2741	to start worker children from some kind of manage rprocess is usually
		2742	preferred, because it is much easier and cleaner, at the expense of having
		2743	to have another binary.
2338		2744
2339		2745
2340	=head1 SECURITY CONSIDERATIONS	2746	=head1 SECURITY CONSIDERATIONS
2341		2747
2342	AnyEvent can be forced to load any event model via	2748	AnyEvent can be forced to load any event model via
…		…
2372	pronounced).	2778	pronounced).
2373		2779
2374		2780
2375	=head1 SEE ALSO	2781	=head1 SEE ALSO
2376		2782
		2783	Tutorial/Introduction: L<AnyEvent::Intro>.
		2784
		2785	FAQ: L<AnyEvent::FAQ>.
		2786
2377	Utility functions: L<AnyEvent::Util>.	2787	Utility functions: L<AnyEvent::Util>.
2378		2788
2379	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2789	Event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>, L<Glib::EV>,
2380	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2790	L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2381		2791
2382	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2792	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2383	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2793	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2384	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2794	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2385	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.	2795	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2386		2796
2387	Non-blocking file handles, sockets, TCP clients and	2797	Non-blocking file handles, sockets, TCP clients and
2388	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2798	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2389		2799
2390	Asynchronous DNS: L<AnyEvent::DNS>.	2800	Asynchronous DNS: L<AnyEvent::DNS>.
2391		2801
2392	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	2802	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2393	L<Coro::Event>,
2394		2803
2395	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	2804	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2396	L<AnyEvent::HTTP>.	2805	L<AnyEvent::HTTP>.
2397		2806
2398		2807
2399	=head1 AUTHOR	2808	=head1 AUTHOR
2400		2809

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