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Revision 1.355 by root, Fri Aug 12 00:53:29 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
…		…
361	invocation, and callback invocation will be synchronous. Synchronous means	396	invocation, and callback invocation will be synchronous. Synchronous means
362	that it might take a while until the signal gets handled by the process,	397	that it might take a while until the signal gets handled by the process,
363	but it is guaranteed not to interrupt any other callbacks.	398	but it is guaranteed not to interrupt any other callbacks.
364		399
365	The main advantage of using these watchers is that you can share a signal	400	The main advantage of using these watchers is that you can share a signal
366	between multiple watchers.	401	between multiple watchers, and AnyEvent will ensure that signals will not
		402	interrupt your program at bad times.
367		403
368	This watcher might use C<%SIG>, so programs overwriting those signals	404	This watcher might use C<%SIG> (depending on the event loop used),
369	directly will likely not work correctly.	405	so programs overwriting those signals directly will likely not work
		406	correctly.
370		407
371	Example: exit on SIGINT	408	Example: exit on SIGINT
372		409
373	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
374		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling) or
		421	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		422	latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
		429	=head3 Signal Races, Delays and Workarounds
		430
		431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		432	callbacks to signals in a generic way, which is a pity, as you cannot
		433	do race-free signal handling in perl, requiring C libraries for
		434	this. AnyEvent will try to do its best, which means in some cases,
		435	signals will be delayed. The maximum time a signal might be delayed is
		436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		437	variable can be changed only before the first signal watcher is created,
		438	and should be left alone otherwise. This variable determines how often
		439	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		440	will cause fewer spurious wake-ups, which is better for power and CPU
		441	saving.
		442
		443	All these problems can be avoided by installing the optional
		444	L<Async::Interrupt> module, which works with most event loops. It will not
		445	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		446	(and not with L<POE> currently, as POE does its own workaround with
		447	one-second latency). For those, you just have to suffer the delays.
		448
375	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
376		450
		451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		452
377	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.
378		454
379	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,
380	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
381	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
382	any trace events (stopped/continued).	458	finished and an exit status is available, not on any trace events
		459	(stopped/continued).
383		460
384	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
385	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
386	callback arguments.	463	callback arguments.
387		464
…		…
403		480
404	This means you cannot create a child watcher as the very first	481	This means you cannot create a child watcher as the very first
405	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
406	watcher before you C<fork> the child (alternatively, you can call	483	watcher before you C<fork> the child (alternatively, you can call
407	C<AnyEvent::detect>).	484	C<AnyEvent::detect>).
		485
		486	As most event loops do not support waiting for child events, they will be
		487	emulated by AnyEvent in most cases, in which case the latency and race
		488	problems mentioned in the description of signal watchers apply.
408		489
409	Example: fork a process and wait for it	490	Example: fork a process and wait for it
410		491
411	my $done = AnyEvent->condvar;	492	my $done = AnyEvent->condvar;
412		493
…		…
424	# do something else, then wait for process exit	505	# do something else, then wait for process exit
425	$done->recv;	506	$done->recv;
426		507
427	=head2 IDLE WATCHERS	508	=head2 IDLE WATCHERS
428		509
429	Sometimes there is a need to do something, but it is not so important	510	$w = AnyEvent->idle (cb => <callback>);
430	to do it instantly, but only when there is nothing better to do. This
431	"nothing better to do" is usually defined to be "no other events need
432	attention by the event loop".
433		511
434	Idle watchers ideally get invoked when the event loop has nothing	512	This will repeatedly invoke the callback after the process becomes idle,
435	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.
436	events. Instead of blocking, the idle watcher is invoked.
437		514
438	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
439	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
440	will simply call the callback "from time to time".	526	will simply call the callback "from time to time".
441		527
442	Example: read lines from STDIN, but only process them when the	528	Example: read lines from STDIN, but only process them when the
443	program is otherwise idle:	529	program is otherwise idle:
…		…
459	});	545	});
460	});	546	});
461		547
462	=head2 CONDITION VARIABLES	548	=head2 CONDITION VARIABLES
463		549
		550	$cv = AnyEvent->condvar;
		551
		552	$cv->send (<list>);
		553	my @res = $cv->recv;
		554
464	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
465	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
466	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
467		558
468	AnyEvent is different, it expects somebody else to run the event loop and	559	AnyEvent is slightly different: it expects somebody else to run the event
469	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).
470		561
471	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
472	because they represent a condition that must become true.	563	they represent a condition that must become true.
		564
		565	Now is probably a good time to look at the examples further below.
473		566
474	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
475	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
476
477	C<cb>, which specifies a callback to be called when the condition variable	569	C<cb>, which specifies a callback to be called when the condition variable
478	becomes true, with the condition variable as the first argument (but not	570	becomes true, with the condition variable as the first argument (but not
479	the results).	571	the results).
480		572
481	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
482	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
483	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<<
484	->send >> method).	576	->send >> method).
485		577
486	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
487	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:
488	in time where multiple outstanding events have been processed. And yet	580
489	another way to call them is transactions - each condition variable can be	581	=over 4
490	used to represent a transaction, which finishes at some point and delivers	582
491	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
492		601
493	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
494	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,
495	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
496	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
…		…
509		618
510	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
511	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
512	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
513	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
514	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
515		624
516	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
517	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
518	for the send to occur.	627	for the send to occur.
519		628
520	Example: wait for a timer.	629	Example: wait for a timer.
521		630
522	# wait till the result is ready	631	# condition: "wait till the timer is fired"
523	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
524		633
525	# do something such as adding a timer	634	# create the timer - we could wait for, say
526	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
527	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
528	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
529	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
530	after => 1,	639	after => 1,
531	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
532	);	641	);
533		642
534	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
535	# calls send	644	# calls ->send
536	$result_ready->recv;	645	$timer_fired->recv;
537		646
538	Example: wait for a timer, but take advantage of the fact that	647	Example: wait for a timer, but take advantage of the fact that condition
539	condition variables are also code references.	648	variables are also callable directly.
540		649
541	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
542	my $delay = AnyEvent->timer (after => 5, cb => $done);	651	my $delay = AnyEvent->timer (after => 5, cb => $done);
543	$done->recv;	652	$done->recv;
544		653
…		…
550		659
551	...	660	...
552		661
553	my @info = $couchdb->info->recv;	662	my @info = $couchdb->info->recv;
554		663
555	And this is how you would just ste a callback to be called whenever the	664	And this is how you would just set a callback to be called whenever the
556	results are available:	665	results are available:
557		666
558	$couchdb->info->cb (sub {	667	$couchdb->info->cb (sub {
559	my @info = $_[0]->recv;	668	my @info = $_[0]->recv;
560	});	669	});
…		…
578	immediately from within send.	687	immediately from within send.
579		688
580	Any arguments passed to the C<send> call will be returned by all	689	Any arguments passed to the C<send> call will be returned by all
581	future C<< ->recv >> calls.	690	future C<< ->recv >> calls.
582		691
583	Condition variables are overloaded so one can call them directly	692	Condition variables are overloaded so one can call them directly (as if
584	(as a code reference). Calling them directly is the same as calling	693	they were a code reference). Calling them directly is the same as calling
585	C<send>. Note, however, that many C-based event loops do not handle	694	C<send>.
586	overloading, so as tempting as it may be, passing a condition variable
587	instead of a callback does not work. Both the pure perl and EV loops
588	support overloading, however, as well as all functions that use perl to
589	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
590	example).
591		695
592	=item $cv->croak ($error)	696	=item $cv->croak ($error)
593		697
594	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
595	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
596		700
597	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
598	user/consumer.	702	user/consumer. Doing it this way instead of calling C<croak> directly
		703	delays the error detection, but has the overwhelming advantage that it
		704	diagnoses the error at the place where the result is expected, and not
		705	deep in some event callback with no connection to the actual code causing
		706	the problem.
599		707
600	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
601		709
602	=item $cv->end	710	=item $cv->end
603		711
…		…
605	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
606	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
607		715
608	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
609	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
610	>>, 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
611	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
612	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.
613		722
614	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
615	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
616	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).
617		726
…		…
639	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
640	sending.	749	sending.
641		750
642	The ping example mentioned above is slightly more complicated, as the	751	The ping example mentioned above is slightly more complicated, as the
643	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
644	begung can potentially be zero:	753	begun can potentially be zero:
645		754
646	my $cv = AnyEvent->condvar;	755	my $cv = AnyEvent->condvar;
647		756
648	my %result;	757	my %result;
649	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
650		759
651	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
652	$cv->begin;	761	$cv->begin;
653	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
654	$result{$host} = ...;	763	$result{$host} = ...;
…		…
670	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
671	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
672	doesn't execute once).	781	doesn't execute once).
673		782
674	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
675	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
676	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
677	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,
678	call C<end>.	787	call C<end>.
679		788
680	=back	789	=back
…		…
687	=over 4	796	=over 4
688		797
689	=item $cv->recv	798	=item $cv->recv
690		799
691	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
692	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
693	normally.	802	normally.
694		803
695	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
696	will return immediately.	805	will return immediately.
697		806
…		…
699	function will call C<croak>.	808	function will call C<croak>.
700		809
701	In list context, all parameters passed to C<send> will be returned,	810	In list context, all parameters passed to C<send> will be returned,
702	in scalar context only the first one will be returned.	811	in scalar context only the first one will be returned.
703		812
		813	Note that doing a blocking wait in a callback is not supported by any
		814	event loop, that is, recursive invocation of a blocking C<< ->recv
		815	>> is not allowed, and the C<recv> call will C<croak> if such a
		816	condition is detected. This condition can be slightly loosened by using
		817	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		818	any thread that doesn't run the event loop itself.
		819
704	Not all event models support a blocking wait - some die in that case	820	Not all event models support a blocking wait - some die in that case
705	(programs might want to do that to stay interactive), so I<if you are	821	(programs might want to do that to stay interactive), so I<if you are
706	using this from a module, never require a blocking wait>, but let the	822	using this from a module, never require a blocking wait>. Instead, let the
707	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
708	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
709	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,
710	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
711		827
712	Another reason I<never> to C<< ->recv >> in a module is that you cannot
713	sensibly have two C<< ->recv >>'s in parallel, as that would require
714	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
715	can supply.
716
717	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
718	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
719	versions and also integrates coroutines into AnyEvent, making blocking
720	C<< ->recv >> calls perfectly safe as long as they are done from another
721	coroutine (one that doesn't run the event loop).
722
723	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
724	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
725	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
726	waits otherwise.	831	waits otherwise.
727		832
728	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
734		839
735	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
736	replaces it before doing so.	841	replaces it before doing so.
737		842
738	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
739	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
740	variable itself. Calling C<recv> inside the callback or at any later time	845	condition variable itself. If the condition is already true, the
741	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.
742		848
743	=back	849	=back
744		850
		851	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		852
		853	The available backend classes are (every class has its own manpage):
		854
		855	=over 4
		856
		857	=item Backends that are autoprobed when no other event loop can be found.
		858
		859	EV is the preferred backend when no other event loop seems to be in
		860	use. If EV is not installed, then AnyEvent will fall back to its own
		861	pure-perl implementation, which is available everywhere as it comes with
		862	AnyEvent itself.
		863
		864	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		865	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
		866
		867	=item Backends that are transparently being picked up when they are used.
		868
		869	These will be used if they are already loaded when the first watcher
		870	is created, in which case it is assumed that the application is using
		871	them. This means that AnyEvent will automatically pick the right backend
		872	when the main program loads an event module before anything starts to
		873	create watchers. Nothing special needs to be done by the main program.
		874
		875	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		876	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		877	AnyEvent::Impl::Tk based on Tk, very broken.
		878	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		879	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		880	AnyEvent::Impl::Irssi used when running within irssi.
		881	AnyEvent::Impl::IOAsync based on IO::Async.
		882	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
		883	AnyEvent::Impl::FLTK based on FLTK.
		884
		885	=item Backends with special needs.
		886
		887	Qt requires the Qt::Application to be instantiated first, but will
		888	otherwise be picked up automatically. As long as the main program
		889	instantiates the application before any AnyEvent watchers are created,
		890	everything should just work.
		891
		892	AnyEvent::Impl::Qt based on Qt.
		893
		894	=item Event loops that are indirectly supported via other backends.
		895
		896	Some event loops can be supported via other modules:
		897
		898	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		899
		900	B<WxWidgets> has no support for watching file handles. However, you can
		901	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		902	polls 20 times per second, which was considered to be too horrible to even
		903	consider for AnyEvent.
		904
		905	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		906	backend, so it can be supported through POE.
		907
		908	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		909	load L<POE> when detecting them, in the hope that POE will pick them up,
		910	in which case everything will be automatic.
		911
		912	=back
		913
745	=head1 GLOBAL VARIABLES AND FUNCTIONS	914	=head1 GLOBAL VARIABLES AND FUNCTIONS
746		915
		916	These are not normally required to use AnyEvent, but can be useful to
		917	write AnyEvent extension modules.
		918
747	=over 4	919	=over 4
748		920
749	=item $AnyEvent::MODEL	921	=item $AnyEvent::MODEL
750		922
751	Contains C<undef> until the first watcher is being created. Then it	923	Contains C<undef> until the first watcher is being created, before the
		924	backend has been autodetected.
		925
752	contains the event model that is being used, which is the name of the	926	Afterwards it contains the event model that is being used, which is the
753	Perl class implementing the model. This class is usually one of the	927	name of the Perl class implementing the model. This class is usually one
754	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	928	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
755	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	929	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
756		930	will be C<urxvt::anyevent>).
757	The known classes so far are:
758
759	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
760	AnyEvent::Impl::Event based on Event, second best choice.
761	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
762	AnyEvent::Impl::Glib based on Glib, third-best choice.
763	AnyEvent::Impl::Tk based on Tk, very bad choice.
764	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
765	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
766	AnyEvent::Impl::POE based on POE, not generic enough for full support.
767
768	# warning, support for IO::Async is only partial, as it is too broken
769	# and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
770	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
771
772	There is no support for WxWidgets, as WxWidgets has no support for
773	watching file handles. However, you can use WxWidgets through the
774	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
775	second, which was considered to be too horrible to even consider for
776	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
777	it's adaptor.
778
779	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
780	autodetecting them.
781		931
782	=item AnyEvent::detect	932	=item AnyEvent::detect
783		933
784	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	934	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
785	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
786	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
787	runtime.	937	runtime, and not e.g. during initialisation of your module.
		938
		939	If you need to do some initialisation before AnyEvent watchers are
		940	created, use C<post_detect>.
788		941
789	=item $guard = AnyEvent::post_detect { BLOCK }	942	=item $guard = AnyEvent::post_detect { BLOCK }
790		943
791	Arranges for the code block to be executed as soon as the event model is	944	Arranges for the code block to be executed as soon as the event model is
792	autodetected (or immediately if this has already happened).	945	autodetected (or immediately if that has already happened).
		946
		947	The block will be executed I<after> the actual backend has been detected
		948	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		949	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		950	other initialisations - see the sources of L<AnyEvent::Strict> or
		951	L<AnyEvent::AIO> to see how this is used.
		952
		953	The most common usage is to create some global watchers, without forcing
		954	event module detection too early, for example, L<AnyEvent::AIO> creates
		955	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		956	avoid autodetecting the event module at load time.
793		957
794	If called in scalar or list context, then it creates and returns an object	958	If called in scalar or list context, then it creates and returns an object
795	that automatically removes the callback again when it is destroyed. See	959	that automatically removes the callback again when it is destroyed (or
		960	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
796	L<Coro::BDB> for a case where this is useful.	961	a case where this is useful.
		962
		963	Example: Create a watcher for the IO::AIO module and store it in
		964	C<$WATCHER>, but do so only do so after the event loop is initialised.
		965
		966	our WATCHER;
		967
		968	my $guard = AnyEvent::post_detect {
		969	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		970	};
		971
		972	# the ||= is important in case post_detect immediately runs the block,
		973	# as to not clobber the newly-created watcher. assigning both watcher and
		974	# post_detect guard to the same variable has the advantage of users being
		975	# able to just C<undef $WATCHER> if the watcher causes them grief.
		976
		977	$WATCHER ||= $guard;
797		978
798	=item @AnyEvent::post_detect	979	=item @AnyEvent::post_detect
799		980
800	If there are any code references in this array (you can C<push> to it	981	If there are any code references in this array (you can C<push> to it
801	before or after loading AnyEvent), then they will called directly after	982	before or after loading AnyEvent), then they will be called directly
802	the event loop has been chosen.	983	after the event loop has been chosen.
803		984
804	You should check C<$AnyEvent::MODEL> before adding to this array, though:	985	You should check C<$AnyEvent::MODEL> before adding to this array, though:
805	if it contains a true value then the event loop has already been detected,	986	if it is defined then the event loop has already been detected, and the
806	and the array will be ignored.	987	array will be ignored.
807		988
808	Best use C<AnyEvent::post_detect { BLOCK }> instead.	989	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		990	it, as it takes care of these details.
		991
		992	This variable is mainly useful for modules that can do something useful
		993	when AnyEvent is used and thus want to know when it is initialised, but do
		994	not need to even load it by default. This array provides the means to hook
		995	into AnyEvent passively, without loading it.
		996
		997	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		998	together, you could put this into Coro (this is the actual code used by
		999	Coro to accomplish this):
		1000
		1001	if (defined $AnyEvent::MODEL) {
		1002	# AnyEvent already initialised, so load Coro::AnyEvent
		1003	require Coro::AnyEvent;
		1004	} else {
		1005	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1006	# as soon as it is
		1007	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1008	}
		1009
		1010	=item AnyEvent::postpone { BLOCK }
		1011
		1012	Arranges for the block to be executed as soon as possible, but not before
		1013	the call itself returns. In practise, the block will be executed just
		1014	before the event loop polls for new events, or shortly afterwards.
		1015
		1016	This function never returns anything (to make the C<return postpone { ...
		1017	}> idiom more useful.
		1018
		1019	To understand the usefulness of this function, consider a function that
		1020	asynchronously does something for you and returns some transaction
		1021	object or guard to let you cancel the operation. For example,
		1022	C<AnyEvent::Socket::tcp_connect>:
		1023
		1024	# start a conenction attempt unless one is active
		1025	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1026	delete $self->{connect_guard};
		1027	...
		1028	};
		1029
		1030	Imagine that this function could instantly call the callback, for
		1031	example, because it detects an obvious error such as a negative port
		1032	number. Invoking the callback before the function returns causes problems
		1033	however: the callback will be called and will try to delete the guard
		1034	object. But since the function hasn't returned yet, there is nothing to
		1035	delete. When the function eventually returns it will assign the guard
		1036	object to C<< $self->{connect_guard} >>, where it will likely never be
		1037	deleted, so the program thinks it is still trying to connect.
		1038
		1039	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1040	callback directly on error:
		1041
		1042	$cb->(undef), return # signal error to callback, BAD!
		1043	if $some_error_condition;
		1044
		1045	It should use C<postpone>:
		1046
		1047	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1048	if $some_error_condition;
809		1049
810	=back	1050	=back
811		1051
812	=head1 WHAT TO DO IN A MODULE	1052	=head1 WHAT TO DO IN A MODULE
813		1053
…		…
824	because it will stall the whole program, and the whole point of using	1064	because it will stall the whole program, and the whole point of using
825	events is to stay interactive.	1065	events is to stay interactive.
826		1066
827	It is fine, however, to call C<< ->recv >> when the user of your module	1067	It is fine, however, to call C<< ->recv >> when the user of your module
828	requests it (i.e. if you create a http request object ad have a method	1068	requests it (i.e. if you create a http request object ad have a method
829	called C<results> that returns the results, it should call C<< ->recv >>	1069	called C<results> that returns the results, it may call C<< ->recv >>
830	freely, as the user of your module knows what she is doing. always).	1070	freely, as the user of your module knows what she is doing. Always).
831		1071
832	=head1 WHAT TO DO IN THE MAIN PROGRAM	1072	=head1 WHAT TO DO IN THE MAIN PROGRAM
833		1073
834	There will always be a single main program - the only place that should	1074	There will always be a single main program - the only place that should
835	dictate which event model to use.	1075	dictate which event model to use.
836		1076
837	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1077	If the program is not event-based, it need not do anything special, even
838	do anything special (it does not need to be event-based) and let AnyEvent	1078	when it depends on a module that uses an AnyEvent. If the program itself
839	decide which implementation to chose if some module relies on it.	1079	uses AnyEvent, but does not care which event loop is used, all it needs
		1080	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1081	available loop implementation.
840		1082
841	If the main program relies on a specific event model - for example, in	1083	If the main program relies on a specific event model - for example, in
842	Gtk2 programs you have to rely on the Glib module - you should load the	1084	Gtk2 programs you have to rely on the Glib module - you should load the
843	event module before loading AnyEvent or any module that uses it: generally	1085	event module before loading AnyEvent or any module that uses it: generally
844	speaking, you should load it as early as possible. The reason is that	1086	speaking, you should load it as early as possible. The reason is that
845	modules might create watchers when they are loaded, and AnyEvent will	1087	modules might create watchers when they are loaded, and AnyEvent will
846	decide on the event model to use as soon as it creates watchers, and it	1088	decide on the event model to use as soon as it creates watchers, and it
847	might chose the wrong one unless you load the correct one yourself.	1089	might choose the wrong one unless you load the correct one yourself.
848		1090
849	You can chose to use a pure-perl implementation by loading the	1091	You can chose to use a pure-perl implementation by loading the
850	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1092	C<AnyEvent::Loop> module, which gives you similar behaviour
851	everywhere, but letting AnyEvent chose the model is generally better.	1093	everywhere, but letting AnyEvent chose the model is generally better.
852		1094
853	=head2 MAINLOOP EMULATION	1095	=head2 MAINLOOP EMULATION
854		1096
855	Sometimes (often for short test scripts, or even standalone programs who	1097	Sometimes (often for short test scripts, or even standalone programs who
…		…
868		1110
869		1111
870	=head1 OTHER MODULES	1112	=head1 OTHER MODULES
871		1113
872	The following is a non-exhaustive list of additional modules that use	1114	The following is a non-exhaustive list of additional modules that use
873	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1115	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
874	in the same program. Some of the modules come with AnyEvent, some are	1116	modules and other event loops in the same program. Some of the modules
875	available via CPAN.	1117	come as part of AnyEvent, the others are available via CPAN.
876		1118
877	=over 4	1119	=over 4
878		1120
879	=item L<AnyEvent::Util>	1121	=item L<AnyEvent::Util>
880		1122
881	Contains various utility functions that replace often-used but blocking	1123	Contains various utility functions that replace often-used blocking
882	functions such as C<inet_aton> by event-/callback-based versions.	1124	functions such as C<inet_aton> with event/callback-based versions.
883		1125
884	=item L<AnyEvent::Socket>	1126	=item L<AnyEvent::Socket>
885		1127
886	Provides various utility functions for (internet protocol) sockets,	1128	Provides various utility functions for (internet protocol) sockets,
887	addresses and name resolution. Also functions to create non-blocking tcp	1129	addresses and name resolution. Also functions to create non-blocking tcp
…		…
889		1131
890	=item L<AnyEvent::Handle>	1132	=item L<AnyEvent::Handle>
891		1133
892	Provide read and write buffers, manages watchers for reads and writes,	1134	Provide read and write buffers, manages watchers for reads and writes,
893	supports raw and formatted I/O, I/O queued and fully transparent and	1135	supports raw and formatted I/O, I/O queued and fully transparent and
894	non-blocking SSL/TLS.	1136	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
895		1137
896	=item L<AnyEvent::DNS>	1138	=item L<AnyEvent::DNS>
897		1139
898	Provides rich asynchronous DNS resolver capabilities.	1140	Provides rich asynchronous DNS resolver capabilities.
899		1141
		1142	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1143
		1144	Implement event-based interfaces to the protocols of the same name (for
		1145	the curious, IGS is the International Go Server and FCP is the Freenet
		1146	Client Protocol).
		1147
		1148	=item L<AnyEvent::Handle::UDP>
		1149
		1150	Here be danger!
		1151
		1152	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1153	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1154	its use of a stream-based API with a protocol that isn't streamable, that
		1155	the only way to improve it is to delete it.
		1156
		1157	It features data corruption (but typically only under load) and general
		1158	confusion. On top, the author is not only clueless about UDP but also
		1159	fact-resistant - some gems of his understanding: "connect doesn't work
		1160	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1161	packets", "I don't need to implement proper error checking as UDP doesn't
		1162	support error checking" and so on - he doesn't even understand what's
		1163	wrong with his module when it is explained to him.
		1164
900	=item L<AnyEvent::HTTP>	1165	=item L<AnyEvent::DBI>
901		1166
902	A simple-to-use HTTP library that is capable of making a lot of concurrent	1167	Executes L<DBI> requests asynchronously in a proxy process for you,
903	HTTP requests.	1168	notifying you in an event-based way when the operation is finished.
		1169
		1170	=item L<AnyEvent::AIO>
		1171
		1172	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1173	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1174	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1175	file I/O, and much more.
904		1176
905	=item L<AnyEvent::HTTPD>	1177	=item L<AnyEvent::HTTPD>
906		1178
907	Provides a simple web application server framework.	1179	A simple embedded webserver.
908		1180
909	=item L<AnyEvent::FastPing>	1181	=item L<AnyEvent::FastPing>
910		1182
911	The fastest ping in the west.	1183	The fastest ping in the west.
912		1184
913	=item L<AnyEvent::DBI>
914
915	Executes L<DBI> requests asynchronously in a proxy process.
916
917	=item L<AnyEvent::AIO>
918
919	Truly asynchronous I/O, should be in the toolbox of every event
920	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
921	together.
922
923	=item L<AnyEvent::BDB>
924
925	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
926	L<BDB> and AnyEvent together.
927
928	=item L<AnyEvent::GPSD>
929
930	A non-blocking interface to gpsd, a daemon delivering GPS information.
931
932	=item L<AnyEvent::IGS>
933
934	A non-blocking interface to the Internet Go Server protocol (used by
935	L<App::IGS>).
936
937	=item L<AnyEvent::IRC>
938
939	AnyEvent based IRC client module family (replacing the older Net::IRC3).
940
941	=item L<Net::XMPP2>
942
943	AnyEvent based XMPP (Jabber protocol) module family.
944
945	=item L<Net::FCP>
946
947	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
948	of AnyEvent.
949
950	=item L<Event::ExecFlow>
951
952	High level API for event-based execution flow control.
953
954	=item L<Coro>	1185	=item L<Coro>
955		1186
956	Has special support for AnyEvent via L<Coro::AnyEvent>.	1187	Has special support for AnyEvent via L<Coro::AnyEvent>.
957		1188
958	=item L<IO::Lambda>
959
960	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
961
962	=back	1189	=back
963		1190
964	=cut	1191	=cut
965		1192
966	package AnyEvent;	1193	package AnyEvent;
967		1194
968	no warnings;	1195	# basically a tuned-down version of common::sense
969	use strict qw(vars subs);	1196	sub common_sense {
		1197	# from common:.sense 3.4
		1198	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
		1199	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1200	$^H |= 0x00000600;
		1201	}
970		1202
		1203	BEGIN { AnyEvent::common_sense }
		1204
971	use Carp;	1205	use Carp ();
972		1206
973	our $VERSION = 4.8;	1207	our $VERSION = '5.34';
974	our $MODEL;	1208	our $MODEL;
975		1209
976	our $AUTOLOAD;	1210	our $AUTOLOAD;
977	our @ISA;	1211	our @ISA;
978		1212
979	our @REGISTRY;	1213	our @REGISTRY;
980		1214
981	our $WIN32;	1215	our $VERBOSE;
982		1216
983	BEGIN {	1217	BEGIN {
984	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1218	require "AnyEvent/constants.pl";
		1219
985	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1220	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
986		1221
987	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1222	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
988	if ${^TAINT};	1223	if ${^TAINT};
989	}
990		1224
991	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1225	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1226
		1227	}
		1228
		1229	our $MAX_SIGNAL_LATENCY = 10;
992		1230
993	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1231	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
994		1232
995	{	1233	{
996	my $idx;	1234	my $idx;
997	$PROTOCOL{$_} = ++$idx	1235	$PROTOCOL{$_} = ++$idx
998	for reverse split /\s*,\s*/,	1236	for reverse split /\s*,\s*/,
999	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1237	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1000	}	1238	}
1001		1239
		1240	our @post_detect;
		1241
		1242	sub post_detect(&) {
		1243	my ($cb) = @_;
		1244
		1245	push @post_detect, $cb;
		1246
		1247	defined wantarray
		1248	? bless \$cb, "AnyEvent::Util::postdetect"
		1249	: ()
		1250	}
		1251
		1252	sub AnyEvent::Util::postdetect::DESTROY {
		1253	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1254	}
		1255
		1256	our $POSTPONE_W;
		1257	our @POSTPONE;
		1258
		1259	sub _postpone_exec {
		1260	undef $POSTPONE_W;
		1261
		1262	&{ shift @POSTPONE }
		1263	while @POSTPONE;
		1264	}
		1265
		1266	sub postpone(&) {
		1267	push @POSTPONE, shift;
		1268
		1269	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1270
		1271	()
		1272	}
		1273
1002	my @models = (	1274	our @models = (
1003	[EV:: => AnyEvent::Impl::EV::],	1275	[EV:: => AnyEvent::Impl::EV:: , 1],
1004	[Event:: => AnyEvent::Impl::Event::],	1276	[AnyEvent::Loop:: => AnyEvent::Impl::Perl:: , 1],
1005	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
1006	# everything below here will not be autoprobed	1277	# everything below here will not (normally) be autoprobed
1007	# as the pureperl backend should work everywhere	1278	# as the pure perl backend should work everywhere
1008	# and is usually faster	1279	# and is usually faster
		1280	[Event:: => AnyEvent::Impl::Event::, 1],
		1281	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1282	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1283	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1009	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1284	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1010	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
1011	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1012	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1285	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1013	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1286	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1014	[Wx:: => AnyEvent::Impl::POE::],	1287	[Wx:: => AnyEvent::Impl::POE::],
1015	[Prima:: => AnyEvent::Impl::POE::],	1288	[Prima:: => AnyEvent::Impl::POE::],
1016	# IO::Async is just too broken - we would need workaorunds for its	1289	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1017	# byzantine signal and broken child handling, among others.	1290	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1018	# IO::Async is rather hard to detect, as it doesn't have any	1291	[FLTK:: => AnyEvent::Impl::FLTK::],
1019	# obvious default class.
1020	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1021	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1022	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1023	);	1292	);
1024		1293
1025	our %method = map +($_ => 1),	1294	our %method = map +($_ => 1),
1026	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1295	qw(io timer time now now_update signal child idle condvar DESTROY);
1027		1296
1028	our @post_detect;
1029
1030	sub post_detect(&) {	1297	sub detect() {
1031	my ($cb) = @_;	1298	# free some memory
		1299	*detect = sub () { $MODEL };
1032		1300
1033	if ($MODEL) {	1301	local $!; # for good measure
1034	$cb->();	1302	local $SIG{__DIE__};
1035		1303
1036	1	1304	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1305	my $model = $1;
		1306	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1307	if (eval "require $model") {
		1308	$MODEL = $model;
		1309	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1037	} else {	1310	} else {
1038	push @post_detect, $cb;	1311	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1039		1312	}
1040	defined wantarray
1041	? bless \$cb, "AnyEvent::Util::postdetect"
1042	: ()
1043	}	1313	}
1044	}
1045		1314
1046	sub AnyEvent::Util::postdetect::DESTROY {	1315	# check for already loaded models
1047	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1048	}
1049
1050	sub detect() {
1051	unless ($MODEL) {	1316	unless ($MODEL) {
1052	no strict 'refs';	1317	for (@REGISTRY, @models) {
1053	local $SIG{__DIE__};	1318	my ($package, $model) = @$_;
1054		1319	if (${"$package\::VERSION"} > 0) {
1055	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1056	my $model = "AnyEvent::Impl::$1";
1057	if (eval "require $model") {	1320	if (eval "require $model") {
1058	$MODEL = $model;	1321	$MODEL = $model;
1059	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1322	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1060	} else {	1323	last;
1061	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1324	}
1062	}	1325	}
1063	}	1326	}
1064		1327
1065	# check for already loaded models
1066	unless ($MODEL) {	1328	unless ($MODEL) {
		1329	# try to autoload a model
1067	for (@REGISTRY, @models) {	1330	for (@REGISTRY, @models) {
1068	my ($package, $model) = @$_;	1331	my ($package, $model, $autoload) = @$_;
		1332	if (
		1333	$autoload
		1334	and eval "require $package"
1069	if (${"$package\::VERSION"} > 0) {	1335	and ${"$package\::VERSION"} > 0
1070	if (eval "require $model") {	1336	and eval "require $model"
		1337	) {
1071	$MODEL = $model;	1338	$MODEL = $model;
1072	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1339	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1073	last;	1340	last;
1074	}
1075	}	1341	}
1076	}	1342	}
1077		1343
1078	unless ($MODEL) {
1079	# try to load a model
1080
1081	for (@REGISTRY, @models) {
1082	my ($package, $model) = @$_;
1083	if (eval "require $package"
1084	and ${"$package\::VERSION"} > 0
1085	and eval "require $model") {
1086	$MODEL = $model;
1087	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1088	last;
1089	}
1090	}
1091
1092	$MODEL	1344	$MODEL
1093	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1345	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?\n";
1094	}
1095	}	1346	}
1096
1097	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1098
1099	unshift @ISA, $MODEL;
1100
1101	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1102
1103	(shift @post_detect)->() while @post_detect;
1104	}	1347	}
1105		1348
		1349	# free memory only needed for probing
		1350	undef @models;
		1351	undef @REGISTRY;
		1352
		1353	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1354	unshift @ISA, $MODEL;
		1355
		1356	# now nuke some methods that are overridden by the backend.
		1357	# SUPER usage is not allowed in these.
		1358	for (qw(time signal child idle)) {
		1359	undef &{"AnyEvent::Base::$_"}
		1360	if defined &{"$MODEL\::$_"};
		1361	}
		1362
		1363	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1364	eval { require AnyEvent::Strict };
		1365	warn "AnyEvent: cannot load AnyEvent::Strict: $@"
		1366	if $@ && $VERBOSE;
		1367	}
		1368
		1369	(shift @post_detect)->() while @post_detect;
		1370	undef @post_detect;
		1371
		1372	*post_detect = sub(&) {
		1373	shift->();
		1374
		1375	undef
		1376	};
		1377
		1378	# recover a few more bytes
		1379	postpone {
		1380	undef &AUTOLOAD;
		1381	};
		1382
1106	$MODEL	1383	$MODEL
1107	}	1384	}
		1385
		1386	our %method = map +($_ => 1),
		1387	qw(io timer time now now_update signal child idle condvar DESTROY);
1108		1388
1109	sub AUTOLOAD {	1389	sub AUTOLOAD {
1110	(my $func = $AUTOLOAD) =~ s/.*://;	1390	(my $func = $AUTOLOAD) =~ s/.*://;
1111		1391
1112	$method{$func}	1392	$method{$func}
1113	or croak "$func: not a valid method for AnyEvent objects";	1393	or Carp::croak "$func: not a valid AnyEvent class method";
1114		1394
1115	detect unless $MODEL;	1395	# free some memory
		1396	undef %method;
		1397
		1398	detect;
1116		1399
1117	my $class = shift;	1400	my $class = shift;
1118	$class->$func (@_);	1401	$class->$func (@_);
1119	}	1402	}
1120		1403
…		…
1123	# allow only one watcher per fd, so we dup it to get a different one).	1406	# allow only one watcher per fd, so we dup it to get a different one).
1124	sub _dupfh($$;$$) {	1407	sub _dupfh($$;$$) {
1125	my ($poll, $fh, $r, $w) = @_;	1408	my ($poll, $fh, $r, $w) = @_;
1126		1409
1127	# cygwin requires the fh mode to be matching, unix doesn't	1410	# cygwin requires the fh mode to be matching, unix doesn't
1128	my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">");	1411	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1129		1412
1130	open my $fh2, "$mode&", $fh	1413	open my $fh2, $mode, $fh
1131	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";	1414	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1132		1415
1133	# we assume CLOEXEC is already set by perl in all important cases	1416	# we assume CLOEXEC is already set by perl in all important cases
1134		1417
1135	($fh2, $rw)	1418	($fh2, $rw)
1136	}	1419	}
1137		1420
		1421	=head1 SIMPLIFIED AE API
		1422
		1423	Starting with version 5.0, AnyEvent officially supports a second, much
		1424	simpler, API that is designed to reduce the calling, typing and memory
		1425	overhead by using function call syntax and a fixed number of parameters.
		1426
		1427	See the L<AE> manpage for details.
		1428
		1429	=cut
		1430
		1431	package AE;
		1432
		1433	our $VERSION = $AnyEvent::VERSION;
		1434
		1435
		1436	sub _reset() {
		1437	eval q{
		1438	# fall back to the main API by default - backends and AnyEvent::Base
		1439	# implementations can overwrite these.
		1440
		1441	sub io($$$) {
		1442	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1443	}
		1444
		1445	sub timer($$$) {
		1446	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1447	}
		1448
		1449	sub signal($$) {
		1450	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1451	}
		1452
		1453	sub child($$) {
		1454	AnyEvent->child (pid => $_[0], cb => $_[1])
		1455	}
		1456
		1457	sub idle($) {
		1458	AnyEvent->idle (cb => $_[0])
		1459	}
		1460
		1461	sub cv(;&) {
		1462	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1463	}
		1464
		1465	sub now() {
		1466	AnyEvent->now
		1467	}
		1468
		1469	sub now_update() {
		1470	AnyEvent->now_update
		1471	}
		1472
		1473	sub time() {
		1474	AnyEvent->time
		1475	}
		1476
		1477	*postpone = \&AnyEvent::postpone;
		1478	};
		1479	die if $@;
		1480	}
		1481
		1482	BEGIN { _reset }
		1483
1138	package AnyEvent::Base;	1484	package AnyEvent::Base;
1139		1485
1140	# default implementations for many methods	1486	# default implementations for many methods
1141		1487
1142	BEGIN {	1488	sub time {
		1489	eval q{ # poor man's autoloading {}
		1490	# probe for availability of Time::HiRes
1143	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1491	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1492	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1144	*_time = \&Time::HiRes::time;	1493	*AE::time = \&Time::HiRes::time;
1145	# if (eval "use POSIX (); (POSIX::times())...	1494	# if (eval "use POSIX (); (POSIX::times())...
1146	} else {	1495	} else {
		1496	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1147	*_time = sub { time }; # epic fail	1497	*AE::time = sub (){ time }; # epic fail
		1498	}
		1499
		1500	*time = sub { AE::time }; # different prototypes
		1501	};
		1502	die if $@;
		1503
		1504	&time
		1505	}
		1506
		1507	*now = \&time;
		1508
		1509	sub now_update { }
		1510
		1511	sub _poll {
		1512	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1513	}
		1514
		1515	# default implementation for ->condvar
		1516	# in fact, the default should not be overwritten
		1517
		1518	sub condvar {
		1519	eval q{ # poor man's autoloading {}
		1520	*condvar = sub {
		1521	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1522	};
		1523
		1524	*AE::cv = sub (;&) {
		1525	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1526	};
		1527	};
		1528	die if $@;
		1529
		1530	&condvar
		1531	}
		1532
		1533	# default implementation for ->signal
		1534
		1535	our $HAVE_ASYNC_INTERRUPT;
		1536
		1537	sub _have_async_interrupt() {
		1538	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1539	&& eval "use Async::Interrupt 1.02 (); 1")
		1540	unless defined $HAVE_ASYNC_INTERRUPT;
		1541
		1542	$HAVE_ASYNC_INTERRUPT
		1543	}
		1544
		1545	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1546	our (%SIG_ASY, %SIG_ASY_W);
		1547	our ($SIG_COUNT, $SIG_TW);
		1548
		1549	# install a dummy wakeup watcher to reduce signal catching latency
		1550	# used by Impls
		1551	sub _sig_add() {
		1552	unless ($SIG_COUNT++) {
		1553	# try to align timer on a full-second boundary, if possible
		1554	my $NOW = AE::now;
		1555
		1556	$SIG_TW = AE::timer
		1557	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1558	$MAX_SIGNAL_LATENCY,
		1559	sub { } # just for the PERL_ASYNC_CHECK
		1560	;
1148	}	1561	}
1149	}	1562	}
1150		1563
1151	sub time { _time }	1564	sub _sig_del {
1152	sub now { _time }	1565	undef $SIG_TW
1153	sub now_update { }	1566	unless --$SIG_COUNT;
1154
1155	# default implementation for ->condvar
1156
1157	sub condvar {
1158	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1159	}	1567	}
1160		1568
1161	# default implementation for ->signal	1569	our $_sig_name_init; $_sig_name_init = sub {
		1570	eval q{ # poor man's autoloading {}
		1571	undef $_sig_name_init;
1162		1572
1163	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1573	if (_have_async_interrupt) {
		1574	*sig2num = \&Async::Interrupt::sig2num;
		1575	*sig2name = \&Async::Interrupt::sig2name;
		1576	} else {
		1577	require Config;
1164		1578
1165	sub _signal_exec {	1579	my %signame2num;
1166	sysread $SIGPIPE_R, my $dummy, 4;	1580	@signame2num{ split ' ', $Config::Config{sig_name} }
		1581	= split ' ', $Config::Config{sig_num};
1167		1582
1168	while (%SIG_EV) {	1583	my @signum2name;
1169	for (keys %SIG_EV) {	1584	@signum2name[values %signame2num] = keys %signame2num;
1170	delete $SIG_EV{$_};	1585
1171	$_->() for values %{ $SIG_CB{$_} || {} };	1586	*sig2num = sub($) {
		1587	$_[0] > 0 ? shift : $signame2num{+shift}
		1588	};
		1589	*sig2name = sub ($) {
		1590	$_[0] > 0 ? $signum2name[+shift] : shift
		1591	};
1172	}	1592	}
1173	}	1593	};
1174	}	1594	die if $@;
		1595	};
		1596
		1597	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1598	sub sig2name($) { &$_sig_name_init; &sig2name }
1175		1599
1176	sub signal {	1600	sub signal {
1177	my (undef, %arg) = @_;	1601	eval q{ # poor man's autoloading {}
		1602	# probe for availability of Async::Interrupt
		1603	if (_have_async_interrupt) {
		1604	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1178		1605
1179	unless ($SIGPIPE_R) {	1606	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1180	require Fcntl;	1607	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1181		1608
1182	if (AnyEvent::WIN32) {
1183	require AnyEvent::Util;
1184
1185	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1186	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1187	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1188	} else {	1609	} else {
		1610	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1611
		1612	if (AnyEvent::WIN32) {
		1613	require AnyEvent::Util;
		1614
		1615	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1616	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1617	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1618	} else {
1189	pipe $SIGPIPE_R, $SIGPIPE_W;	1619	pipe $SIGPIPE_R, $SIGPIPE_W;
1190	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1620	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1191	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1621	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1192		1622
1193	# not strictly required, as $^F is normally 2, but let's make sure...	1623	# not strictly required, as $^F is normally 2, but let's make sure...
1194	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1624	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1195	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1625	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1626	}
		1627
		1628	$SIGPIPE_R
		1629	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1630
		1631	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1196	}	1632	}
1197		1633
1198	$SIGPIPE_R	1634	*signal = $HAVE_ASYNC_INTERRUPT
1199	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1635	? sub {
		1636	my (undef, %arg) = @_;
1200		1637
1201	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1638	# async::interrupt
1202	}
1203
1204	my $signal = uc $arg{signal}	1639	my $signal = sig2num $arg{signal};
1205	or Carp::croak "required option 'signal' is missing";
1206
1207	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1640	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1641
		1642	$SIG_ASY{$signal} ||= new Async::Interrupt
		1643	cb => sub { undef $SIG_EV{$signal} },
		1644	signal => $signal,
		1645	pipe => [$SIGPIPE_R->filenos],
		1646	pipe_autodrain => 0,
		1647	;
		1648
		1649	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1650	}
		1651	: sub {
		1652	my (undef, %arg) = @_;
		1653
		1654	# pure perl
		1655	my $signal = sig2name $arg{signal};
		1656	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1657
1208	$SIG{$signal} ||= sub {	1658	$SIG{$signal} ||= sub {
1209	local $!;	1659	local $!;
1210	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1660	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1211	undef $SIG_EV{$signal};	1661	undef $SIG_EV{$signal};
		1662	};
		1663
		1664	# can't do signal processing without introducing races in pure perl,
		1665	# so limit the signal latency.
		1666	_sig_add;
		1667
		1668	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1669	}
		1670	;
		1671
		1672	*AnyEvent::Base::signal::DESTROY = sub {
		1673	my ($signal, $cb) = @{$_[0]};
		1674
		1675	_sig_del;
		1676
		1677	delete $SIG_CB{$signal}{$cb};
		1678
		1679	$HAVE_ASYNC_INTERRUPT
		1680	? delete $SIG_ASY{$signal}
		1681	: # delete doesn't work with older perls - they then
		1682	# print weird messages, or just unconditionally exit
		1683	# instead of getting the default action.
		1684	undef $SIG{$signal}
		1685	unless keys %{ $SIG_CB{$signal} };
		1686	};
		1687
		1688	*_signal_exec = sub {
		1689	$HAVE_ASYNC_INTERRUPT
		1690	? $SIGPIPE_R->drain
		1691	: sysread $SIGPIPE_R, (my $dummy), 9;
		1692
		1693	while (%SIG_EV) {
		1694	for (keys %SIG_EV) {
		1695	delete $SIG_EV{$_};
		1696	&$_ for values %{ $SIG_CB{$_} || {} };
		1697	}
		1698	}
		1699	};
1212	};	1700	};
		1701	die if $@;
1213		1702
1214	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1703	&signal
1215	}
1216
1217	sub AnyEvent::Base::signal::DESTROY {
1218	my ($signal, $cb) = @{$_[0]};
1219
1220	delete $SIG_CB{$signal}{$cb};
1221
1222	# delete doesn't work with older perls - they then
1223	# print weird messages, or just unconditionally exit
1224	# instead of getting the default action.
1225	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1226	}	1704	}
1227		1705
1228	# default implementation for ->child	1706	# default implementation for ->child
1229		1707
1230	our %PID_CB;	1708	our %PID_CB;
1231	our $CHLD_W;	1709	our $CHLD_W;
1232	our $CHLD_DELAY_W;	1710	our $CHLD_DELAY_W;
1233	our $WNOHANG;
1234		1711
1235	sub _sigchld {	1712	# used by many Impl's
1236	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1713	sub _emit_childstatus($$) {
		1714	my (undef, $rpid, $rstatus) = @_;
		1715
		1716	$_->($rpid, $rstatus)
1237	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1717	for values %{ $PID_CB{$rpid} || {} },
1238	(values %{ $PID_CB{0} || {} });	1718	values %{ $PID_CB{0} || {} };
1239	}
1240	}	1719	}
1241		1720
1242	sub child {	1721	sub child {
		1722	eval q{ # poor man's autoloading {}
		1723	*_sigchld = sub {
		1724	my $pid;
		1725
		1726	AnyEvent->_emit_childstatus ($pid, $?)
		1727	while ($pid = waitpid -1, WNOHANG) > 0;
		1728	};
		1729
		1730	*child = sub {
1243	my (undef, %arg) = @_;	1731	my (undef, %arg) = @_;
1244		1732
1245	defined (my $pid = $arg{pid} + 0)	1733	my $pid = $arg{pid};
1246	or Carp::croak "required option 'pid' is missing";	1734	my $cb = $arg{cb};
1247		1735
1248	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1736	$PID_CB{$pid}{$cb+0} = $cb;
1249		1737
1250	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1251
1252	unless ($CHLD_W) {	1738	unless ($CHLD_W) {
1253	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1739	$CHLD_W = AE::signal CHLD => \&_sigchld;
1254	# child could be a zombie already, so make at least one round	1740	# child could be a zombie already, so make at least one round
1255	&_sigchld;	1741	&_sigchld;
1256	}	1742	}
1257		1743
1258	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1744	bless [$pid, $cb+0], "AnyEvent::Base::child"
1259	}	1745	};
1260		1746
1261	sub AnyEvent::Base::child::DESTROY {	1747	*AnyEvent::Base::child::DESTROY = sub {
1262	my ($pid, $cb) = @{$_[0]};	1748	my ($pid, $icb) = @{$_[0]};
1263		1749
1264	delete $PID_CB{$pid}{$cb};	1750	delete $PID_CB{$pid}{$icb};
1265	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1751	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1266		1752
1267	undef $CHLD_W unless keys %PID_CB;	1753	undef $CHLD_W unless keys %PID_CB;
		1754	};
		1755	};
		1756	die if $@;
		1757
		1758	&child
1268	}	1759	}
1269		1760
1270	# idle emulation is done by simply using a timer, regardless	1761	# idle emulation is done by simply using a timer, regardless
1271	# of whether the process is idle or not, and not letting	1762	# of whether the process is idle or not, and not letting
1272	# the callback use more than 50% of the time.	1763	# the callback use more than 50% of the time.
1273	sub idle {	1764	sub idle {
		1765	eval q{ # poor man's autoloading {}
		1766	*idle = sub {
1274	my (undef, %arg) = @_;	1767	my (undef, %arg) = @_;
1275		1768
1276	my ($cb, $w, $rcb) = $arg{cb};	1769	my ($cb, $w, $rcb) = $arg{cb};
1277		1770
1278	$rcb = sub {	1771	$rcb = sub {
1279	if ($cb) {	1772	if ($cb) {
1280	$w = _time;	1773	$w = _time;
1281	&$cb;	1774	&$cb;
1282	$w = _time - $w;	1775	$w = _time - $w;
1283		1776
1284	# never use more then 50% of the time for the idle watcher,	1777	# never use more then 50% of the time for the idle watcher,
1285	# within some limits	1778	# within some limits
1286	$w = 0.0001 if $w < 0.0001;	1779	$w = 0.0001 if $w < 0.0001;
1287	$w = 5 if $w > 5;	1780	$w = 5 if $w > 5;
1288		1781
1289	$w = AnyEvent->timer (after => $w, cb => $rcb);	1782	$w = AE::timer $w, 0, $rcb;
1290	} else {	1783	} else {
1291	# clean up...	1784	# clean up...
1292	undef $w;	1785	undef $w;
1293	undef $rcb;	1786	undef $rcb;
		1787	}
		1788	};
		1789
		1790	$w = AE::timer 0.05, 0, $rcb;
		1791
		1792	bless \\$cb, "AnyEvent::Base::idle"
1294	}	1793	};
		1794
		1795	*AnyEvent::Base::idle::DESTROY = sub {
		1796	undef $${$_[0]};
		1797	};
1295	};	1798	};
		1799	die if $@;
1296		1800
1297	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1801	&idle
1298
1299	bless \\$cb, "AnyEvent::Base::idle"
1300	}
1301
1302	sub AnyEvent::Base::idle::DESTROY {
1303	undef $${$_[0]};
1304	}	1802	}
1305		1803
1306	package AnyEvent::CondVar;	1804	package AnyEvent::CondVar;
1307		1805
1308	our @ISA = AnyEvent::CondVar::Base::;	1806	our @ISA = AnyEvent::CondVar::Base::;
1309		1807
		1808	# only to be used for subclassing
		1809	sub new {
		1810	my $class = shift;
		1811	bless AnyEvent->condvar (@_), $class
		1812	}
		1813
1310	package AnyEvent::CondVar::Base;	1814	package AnyEvent::CondVar::Base;
1311		1815
1312	use overload	1816	#use overload
1313	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1817	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1314	fallback => 1;	1818	# fallback => 1;
		1819
		1820	# save 300+ kilobytes by dirtily hardcoding overloading
		1821	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1822	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1823	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1824	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1825
		1826	our $WAITING;
1315		1827
1316	sub _send {	1828	sub _send {
1317	# nop	1829	# nop
		1830	}
		1831
		1832	sub _wait {
		1833	AnyEvent->_poll until $_[0]{_ae_sent};
1318	}	1834	}
1319		1835
1320	sub send {	1836	sub send {
1321	my $cv = shift;	1837	my $cv = shift;
1322	$cv->{_ae_sent} = [@_];	1838	$cv->{_ae_sent} = [@_];
…		…
1331		1847
1332	sub ready {	1848	sub ready {
1333	$_[0]{_ae_sent}	1849	$_[0]{_ae_sent}
1334	}	1850	}
1335		1851
1336	sub _wait {
1337	AnyEvent->one_event while !$_[0]{_ae_sent};
1338	}
1339
1340	sub recv {	1852	sub recv {
		1853	unless ($_[0]{_ae_sent}) {
		1854	$WAITING
		1855	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1856
		1857	local $WAITING = 1;
1341	$_[0]->_wait;	1858	$_[0]->_wait;
		1859	}
1342		1860
1343	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1861	$_[0]{_ae_croak}
1344	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1862	and Carp::croak $_[0]{_ae_croak};
		1863
		1864	wantarray
		1865	? @{ $_[0]{_ae_sent} }
		1866	: $_[0]{_ae_sent}[0]
1345	}	1867	}
1346		1868
1347	sub cb {	1869	sub cb {
1348	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1870	my $cv = shift;
		1871
		1872	@_
		1873	and $cv->{_ae_cb} = shift
		1874	and $cv->{_ae_sent}
		1875	and (delete $cv->{_ae_cb})->($cv);
		1876
1349	$_[0]{_ae_cb}	1877	$cv->{_ae_cb}
1350	}	1878	}
1351		1879
1352	sub begin {	1880	sub begin {
1353	++$_[0]{_ae_counter};	1881	++$_[0]{_ae_counter};
1354	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1882	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1359	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	1887	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1360	}	1888	}
1361		1889
1362	# undocumented/compatibility with pre-3.4	1890	# undocumented/compatibility with pre-3.4
1363	*broadcast = \&send;	1891	*broadcast = \&send;
1364	*wait = \&_wait;	1892	*wait = \&recv;
1365		1893
1366	=head1 ERROR AND EXCEPTION HANDLING	1894	=head1 ERROR AND EXCEPTION HANDLING
1367		1895
1368	In general, AnyEvent does not do any error handling - it relies on the	1896	In general, AnyEvent does not do any error handling - it relies on the
1369	caller to do that if required. The L<AnyEvent::Strict> module (see also	1897	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1403	C<PERL_ANYEVENT_MODEL>.	1931	C<PERL_ANYEVENT_MODEL>.
1404		1932
1405	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1933	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1406	model it chooses.	1934	model it chooses.
1407		1935
		1936	When set to C<8> or higher, then AnyEvent will report extra information on
		1937	which optional modules it loads and how it implements certain features.
		1938
1408	=item C<PERL_ANYEVENT_STRICT>	1939	=item C<PERL_ANYEVENT_STRICT>
1409		1940
1410	AnyEvent does not do much argument checking by default, as thorough	1941	AnyEvent does not do much argument checking by default, as thorough
1411	argument checking is very costly. Setting this variable to a true value	1942	argument checking is very costly. Setting this variable to a true value
1412	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1943	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1413	check the arguments passed to most method calls. If it finds any problems,	1944	check the arguments passed to most method calls. If it finds any problems,
1414	it will croak.	1945	it will croak.
1415		1946
1416	In other words, enables "strict" mode.	1947	In other words, enables "strict" mode.
1417		1948
1418	Unlike C<use strict>, it is definitely recommended to keep it off in	1949	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1419	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1950	>>, it is definitely recommended to keep it off in production. Keeping
1420	developing programs can be very useful, however.	1951	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1952	can be very useful, however.
1421		1953
1422	=item C<PERL_ANYEVENT_MODEL>	1954	=item C<PERL_ANYEVENT_MODEL>
1423		1955
1424	This can be used to specify the event model to be used by AnyEvent, before	1956	This can be used to specify the event model to be used by AnyEvent, before
1425	auto detection and -probing kicks in. It must be a string consisting	1957	auto detection and -probing kicks in.
1426	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1958
		1959	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		1960	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1427	and the resulting module name is loaded and if the load was successful,	1961	resulting module name is loaded and - if the load was successful - used as
1428	used as event model. If it fails to load AnyEvent will proceed with	1962	event model backend. If it fails to load then AnyEvent will proceed with
1429	auto detection and -probing.	1963	auto detection and -probing.
1430		1964
1431	This functionality might change in future versions.	1965	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		1966	nothing gets prepended and the module name is used as-is (hint: C<::> at
		1967	the end of a string designates a module name and quotes it appropriately).
1432		1968
1433	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1969	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1434	could start your program like this:	1970	could start your program like this:
1435		1971
1436	PERL_ANYEVENT_MODEL=Perl perl ...	1972	PERL_ANYEVENT_MODEL=Perl perl ...
1437		1973
1438	=item C<PERL_ANYEVENT_PROTOCOLS>	1974	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
1487		2023
1488	When neither C<ca_file> nor C<ca_path> was specified during	2024	When neither C<ca_file> nor C<ca_path> was specified during
1489	L<AnyEvent::TLS> context creation, and either of these environment	2025	L<AnyEvent::TLS> context creation, and either of these environment
1490	variables exist, they will be used to specify CA certificate locations	2026	variables exist, they will be used to specify CA certificate locations
1491	instead of a system-dependent default.	2027	instead of a system-dependent default.
		2028
		2029	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		2030
		2031	When these are set to C<1>, then the respective modules are not
		2032	loaded. Mostly good for testing AnyEvent itself.
1492		2033
1493	=back	2034	=back
1494		2035
1495	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	2036	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1496		2037
…		…
1554	warn "read: $input\n"; # output what has been read	2095	warn "read: $input\n"; # output what has been read
1555	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2096	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1556	},	2097	},
1557	);	2098	);
1558		2099
1559	my $time_watcher; # can only be used once
1560
1561	sub new_timer {
1562	$timer = AnyEvent->timer (after => 1, cb => sub {	2100	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1563	warn "timeout\n"; # print 'timeout' about every second	2101	warn "timeout\n"; # print 'timeout' at most every second
1564	&new_timer; # and restart the time
1565	});	2102	});
1566	}
1567
1568	new_timer; # create first timer
1569		2103
1570	$cv->recv; # wait until user enters /^q/i	2104	$cv->recv; # wait until user enters /^q/i
1571		2105
1572	=head1 REAL-WORLD EXAMPLE	2106	=head1 REAL-WORLD EXAMPLE
1573		2107
…		…
1646		2180
1647	The actual code goes further and collects all errors (C<die>s, exceptions)	2181	The actual code goes further and collects all errors (C<die>s, exceptions)
1648	that occurred during request processing. The C<result> method detects	2182	that occurred during request processing. The C<result> method detects
1649	whether an exception as thrown (it is stored inside the $txn object)	2183	whether an exception as thrown (it is stored inside the $txn object)
1650	and just throws the exception, which means connection errors and other	2184	and just throws the exception, which means connection errors and other
1651	problems get reported tot he code that tries to use the result, not in a	2185	problems get reported to the code that tries to use the result, not in a
1652	random callback.	2186	random callback.
1653		2187
1654	All of this enables the following usage styles:	2188	All of this enables the following usage styles:
1655		2189
1656	1. Blocking:	2190	1. Blocking:
…		…
1704	through AnyEvent. The benchmark creates a lot of timers (with a zero	2238	through AnyEvent. The benchmark creates a lot of timers (with a zero
1705	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2239	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1706	which it is), lets them fire exactly once and destroys them again.	2240	which it is), lets them fire exactly once and destroys them again.
1707		2241
1708	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2242	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1709	distribution.	2243	distribution. It uses the L<AE> interface, which makes a real difference
		2244	for the EV and Perl backends only.
1710		2245
1711	=head3 Explanation of the columns	2246	=head3 Explanation of the columns
1712		2247
1713	I<watcher> is the number of event watchers created/destroyed. Since	2248	I<watcher> is the number of event watchers created/destroyed. Since
1714	different event models feature vastly different performances, each event	2249	different event models feature vastly different performances, each event
…		…
1735	watcher.	2270	watcher.
1736		2271
1737	=head3 Results	2272	=head3 Results
1738		2273
1739	name watchers bytes create invoke destroy comment	2274	name watchers bytes create invoke destroy comment
1740	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2275	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1741	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2276	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1742	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2277	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1743	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2278	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1744	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2279	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1745	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2280	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1746	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2281	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1747	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2282	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1748	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2283	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1749	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2284	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1750	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2285	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1751	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2286	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1752		2287
1753	=head3 Discussion	2288	=head3 Discussion
1754		2289
1755	The benchmark does I<not> measure scalability of the event loop very	2290	The benchmark does I<not> measure scalability of the event loop very
1756	well. For example, a select-based event loop (such as the pure perl one)	2291	well. For example, a select-based event loop (such as the pure perl one)
…		…
1768	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2303	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1769	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2304	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1770	cycles with POE.	2305	cycles with POE.
1771		2306
1772	C<EV> is the sole leader regarding speed and memory use, which are both	2307	C<EV> is the sole leader regarding speed and memory use, which are both
1773	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2308	maximal/minimal, respectively. When using the L<AE> API there is zero
		2309	overhead (when going through the AnyEvent API create is about 5-6 times
		2310	slower, with other times being equal, so still uses far less memory than
1774	far less memory than any other event loop and is still faster than Event	2311	any other event loop and is still faster than Event natively).
1775	natively.
1776		2312
1777	The pure perl implementation is hit in a few sweet spots (both the	2313	The pure perl implementation is hit in a few sweet spots (both the
1778	constant timeout and the use of a single fd hit optimisations in the perl	2314	constant timeout and the use of a single fd hit optimisations in the perl
1779	interpreter and the backend itself). Nevertheless this shows that it	2315	interpreter and the backend itself). Nevertheless this shows that it
1780	adds very little overhead in itself. Like any select-based backend its	2316	adds very little overhead in itself. Like any select-based backend its
…		…
1854	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2390	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1855	(1%) are active. This mirrors the activity of large servers with many	2391	(1%) are active. This mirrors the activity of large servers with many
1856	connections, most of which are idle at any one point in time.	2392	connections, most of which are idle at any one point in time.
1857		2393
1858	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2394	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1859	distribution.	2395	distribution. It uses the L<AE> interface, which makes a real difference
		2396	for the EV and Perl backends only.
1860		2397
1861	=head3 Explanation of the columns	2398	=head3 Explanation of the columns
1862		2399
1863	I<sockets> is the number of sockets, and twice the number of "servers" (as	2400	I<sockets> is the number of sockets, and twice the number of "servers" (as
1864	each server has a read and write socket end).	2401	each server has a read and write socket end).
…		…
1872	a new one that moves the timeout into the future.	2409	a new one that moves the timeout into the future.
1873		2410
1874	=head3 Results	2411	=head3 Results
1875		2412
1876	name sockets create request	2413	name sockets create request
1877	EV 20000 69.01 11.16	2414	EV 20000 62.66 7.99
1878	Perl 20000 73.32 35.87	2415	Perl 20000 68.32 32.64
1879	IOAsync 20000 157.00 98.14 epoll	2416	IOAsync 20000 174.06 101.15 epoll
1880	IOAsync 20000 159.31 616.06 poll	2417	IOAsync 20000 174.67 610.84 poll
1881	Event 20000 212.62 257.32	2418	Event 20000 202.69 242.91
1882	Glib 20000 651.16 1896.30	2419	Glib 20000 557.01 1689.52
1883	POE 20000 349.67 12317.24 uses POE::Loop::Event	2420	POE 20000 341.54 12086.32 uses POE::Loop::Event
1884		2421
1885	=head3 Discussion	2422	=head3 Discussion
1886		2423
1887	This benchmark I<does> measure scalability and overall performance of the	2424	This benchmark I<does> measure scalability and overall performance of the
1888	particular event loop.	2425	particular event loop.
…		…
2014	As you can see, the AnyEvent + EV combination even beats the	2551	As you can see, the AnyEvent + EV combination even beats the
2015	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2552	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2016	backend easily beats IO::Lambda and POE.	2553	backend easily beats IO::Lambda and POE.
2017		2554
2018	And even the 100% non-blocking version written using the high-level (and	2555	And even the 100% non-blocking version written using the high-level (and
2019	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2556	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2020	large margin, even though it does all of DNS, tcp-connect and socket I/O	2557	higher level ("unoptimised") abstractions by a large margin, even though
2021	in a non-blocking way.	2558	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2022		2559
2023	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2560	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2024	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2561	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2025	part of the IO::lambda distribution and were used without any changes.	2562	part of the IO::Lambda distribution and were used without any changes.
2026		2563
2027		2564
2028	=head1 SIGNALS	2565	=head1 SIGNALS
2029		2566
2030	AnyEvent currently installs handlers for these signals:	2567	AnyEvent currently installs handlers for these signals:
…		…
2035		2572
2036	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2573	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
2037	emulation for event loops that do not support them natively. Also, some	2574	emulation for event loops that do not support them natively. Also, some
2038	event loops install a similar handler.	2575	event loops install a similar handler.
2039		2576
2040	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will	2577	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2041	reset it to default, to avoid losing child exit statuses.	2578	AnyEvent will reset it to default, to avoid losing child exit statuses.
2042		2579
2043	=item SIGPIPE	2580	=item SIGPIPE
2044		2581
2045	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2582	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
2046	when AnyEvent gets loaded.	2583	when AnyEvent gets loaded.
…		…
2064	if $SIG{CHLD} eq 'IGNORE';	2601	if $SIG{CHLD} eq 'IGNORE';
2065		2602
2066	$SIG{PIPE} = sub { }	2603	$SIG{PIPE} = sub { }
2067	unless defined $SIG{PIPE};	2604	unless defined $SIG{PIPE};
2068		2605
		2606	=head1 RECOMMENDED/OPTIONAL MODULES
		2607
		2608	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2609	its built-in modules) are required to use it.
		2610
		2611	That does not mean that AnyEvent won't take advantage of some additional
		2612	modules if they are installed.
		2613
		2614	This section explains which additional modules will be used, and how they
		2615	affect AnyEvent's operation.
		2616
		2617	=over 4
		2618
		2619	=item L<Async::Interrupt>
		2620
		2621	This slightly arcane module is used to implement fast signal handling: To
		2622	my knowledge, there is no way to do completely race-free and quick
		2623	signal handling in pure perl. To ensure that signals still get
		2624	delivered, AnyEvent will start an interval timer to wake up perl (and
		2625	catch the signals) with some delay (default is 10 seconds, look for
		2626	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2627
		2628	If this module is available, then it will be used to implement signal
		2629	catching, which means that signals will not be delayed, and the event loop
		2630	will not be interrupted regularly, which is more efficient (and good for
		2631	battery life on laptops).
		2632
		2633	This affects not just the pure-perl event loop, but also other event loops
		2634	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2635
		2636	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2637	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2638	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2639	does nothing for those backends.
		2640
		2641	=item L<EV>
		2642
		2643	This module isn't really "optional", as it is simply one of the backend
		2644	event loops that AnyEvent can use. However, it is simply the best event
		2645	loop available in terms of features, speed and stability: It supports
		2646	the AnyEvent API optimally, implements all the watcher types in XS, does
		2647	automatic timer adjustments even when no monotonic clock is available,
		2648	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2649	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2650	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2651
		2652	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2653	then this module will do nothing for you.
		2654
		2655	=item L<Guard>
		2656
		2657	The guard module, when used, will be used to implement
		2658	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2659	lot less memory), but otherwise doesn't affect guard operation much. It is
		2660	purely used for performance.
		2661
		2662	=item L<JSON> and L<JSON::XS>
		2663
		2664	One of these modules is required when you want to read or write JSON data
		2665	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2666	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2667
		2668	=item L<Net::SSLeay>
		2669
		2670	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2671	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2672	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2673
		2674	=item L<Time::HiRes>
		2675
		2676	This module is part of perl since release 5.008. It will be used when the
		2677	chosen event library does not come with a timing source of its own. The
		2678	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
		2679	try to use a monotonic clock for timing stability.
		2680
		2681	=back
		2682
		2683
2069	=head1 FORK	2684	=head1 FORK
2070		2685
2071	Most event libraries are not fork-safe. The ones who are usually are	2686	Most event libraries are not fork-safe. The ones who are usually are
2072	because they rely on inefficient but fork-safe C<select> or C<poll>	2687	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2073	calls. Only L<EV> is fully fork-aware.	2688	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2689	are usually badly thought-out hacks that are incompatible with fork in
		2690	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2691	continue event-processing in both parent and child (or both, if you know
		2692	what you are doing).
		2693
		2694	This means that, in general, you cannot fork and do event processing in
		2695	the child if the event library was initialised before the fork (which
		2696	usually happens when the first AnyEvent watcher is created, or the library
		2697	is loaded).
2074		2698
2075	If you have to fork, you must either do so I<before> creating your first	2699	If you have to fork, you must either do so I<before> creating your first
2076	watcher OR you must not use AnyEvent at all in the child.	2700	watcher OR you must not use AnyEvent at all in the child OR you must do
		2701	something completely out of the scope of AnyEvent.
		2702
		2703	The problem of doing event processing in the parent I<and> the child
		2704	is much more complicated: even for backends that I<are> fork-aware or
		2705	fork-safe, their behaviour is not usually what you want: fork clones all
		2706	watchers, that means all timers, I/O watchers etc. are active in both
		2707	parent and child, which is almost never what you want. USing C<exec>
		2708	to start worker children from some kind of manage rprocess is usually
		2709	preferred, because it is much easier and cleaner, at the expense of having
		2710	to have another binary.
2077		2711
2078		2712
2079	=head1 SECURITY CONSIDERATIONS	2713	=head1 SECURITY CONSIDERATIONS
2080		2714
2081	AnyEvent can be forced to load any event model via	2715	AnyEvent can be forced to load any event model via
…		…
2111	pronounced).	2745	pronounced).
2112		2746
2113		2747
2114	=head1 SEE ALSO	2748	=head1 SEE ALSO
2115		2749
		2750	Tutorial/Introduction: L<AnyEvent::Intro>.
		2751
		2752	FAQ: L<AnyEvent::FAQ>.
		2753
2116	Utility functions: L<AnyEvent::Util>.	2754	Utility functions: L<AnyEvent::Util>.
2117		2755
2118	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2756	Event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>, L<Glib::EV>,
2119	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2757	L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2120		2758
2121	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2759	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2122	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2760	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2123	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2761	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2124	L<AnyEvent::Impl::POE>.	2762	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2125		2763
2126	Non-blocking file handles, sockets, TCP clients and	2764	Non-blocking file handles, sockets, TCP clients and
2127	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2765	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2128		2766
2129	Asynchronous DNS: L<AnyEvent::DNS>.	2767	Asynchronous DNS: L<AnyEvent::DNS>.
2130		2768
2131	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2769	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2132		2770
2133	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2771	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
		2772	L<AnyEvent::HTTP>.
2134		2773
2135		2774
2136	=head1 AUTHOR	2775	=head1 AUTHOR
2137		2776
2138	Marc Lehmann <schmorp@schmorp.de>	2777	Marc Lehmann <schmorp@schmorp.de>

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