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Revision 1.358 by root, Sat Aug 13 02:35:32 2011 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
6	event loops.	6	and POE are various supported event loops/environments.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
12	# file descriptor readable	15	# file handle or descriptor readable
13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14		17
15	# one-shot or repeating timers	18	# one-shot or repeating timers
16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
18		21
19	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
21		24
22	# POSIX signal	25	# POSIX signal
…		…
40	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
41		44
42	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
43	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
		48
		49	=head1 SUPPORT
		50
		51	An FAQ document is available as L<AnyEvent::FAQ>.
		52
		53	There also is a mailinglist for discussing all things AnyEvent, and an IRC
		54	channel, too.
		55
		56	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		57	Repository>, at L<http://anyevent.schmorp.de>, for more info.
45		58
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	59	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		60
48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	61	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49	nowadays. So what is different about AnyEvent?	62	nowadays. So what is different about AnyEvent?
…		…
65	module users into the same thing by forcing them to use the same event	78	module users into the same thing by forcing them to use the same event
66	model you use.	79	model you use.
67		80
68	For modules like POE or IO::Async (which is a total misnomer as it is	81	For modules like POE or IO::Async (which is a total misnomer as it is
69	actually doing all I/O I<synchronously>...), using them in your module is	82	actually doing all I/O I<synchronously>...), using them in your module is
70	like joining a cult: After you joined, you are dependent on them and you	83	like joining a cult: After you join, you are dependent on them and you
71	cannot use anything else, as they are simply incompatible to everything	84	cannot use anything else, as they are simply incompatible to everything
72	that isn't them. What's worse, all the potential users of your	85	that isn't them. What's worse, all the potential users of your
73	module are I<also> forced to use the same event loop you use.	86	module are I<also> forced to use the same event loop you use.
74		87
75	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	88	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
76	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	89	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
77	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if	90	with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module
78	your module uses one of those, every user of your module has to use it,	91	uses one of those, every user of your module has to use it, too. But if
79	too. But if your module uses AnyEvent, it works transparently with all	92	your module uses AnyEvent, it works transparently with all event models it
80	event models it supports (including stuff like IO::Async, as long as those	93	supports (including stuff like IO::Async, as long as those use one of the
81	use one of the supported event loops. It is trivial to add new event loops	94	supported event loops. It is easy to add new event loops to AnyEvent, too,
82	to AnyEvent, too, so it is future-proof).	95	so it is future-proof).
83		96
84	In addition to being free of having to use I<the one and only true event	97	In addition to being free of having to use I<the one and only true event
85	model>, AnyEvent also is free of bloat and policy: with POE or similar	98	model>, AnyEvent also is free of bloat and policy: with POE or similar
86	modules, you get an enormous amount of code and strict rules you have to	99	modules, you get an enormous amount of code and strict rules you have to
87	follow. AnyEvent, on the other hand, is lean and up to the point, by only	100	follow. AnyEvent, on the other hand, is lean and to the point, by only
88	offering the functionality that is necessary, in as thin as a wrapper as	101	offering the functionality that is necessary, in as thin as a wrapper as
89	technically possible.	102	technically possible.
90		103
91	Of course, AnyEvent comes with a big (and fully optional!) toolbox	104	Of course, AnyEvent comes with a big (and fully optional!) toolbox
92	of useful functionality, such as an asynchronous DNS resolver, 100%	105	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
98	useful) and you want to force your users to use the one and only event	111	useful) and you want to force your users to use the one and only event
99	model, you should I<not> use this module.	112	model, you should I<not> use this module.
100		113
101	=head1 DESCRIPTION	114	=head1 DESCRIPTION
102		115
103	L<AnyEvent> provides an identical interface to multiple event loops. This	116	L<AnyEvent> provides a uniform interface to various event loops. This
104	allows module authors to utilise an event loop without forcing module	117	allows module authors to use event loop functionality without forcing
105	users to use the same event loop (as only a single event loop can coexist	118	module users to use a specific event loop implementation (since more
106	peacefully at any one time).	119	than one event loop cannot coexist peacefully).
107		120
108	The interface itself is vaguely similar, but not identical to the L<Event>	121	The interface itself is vaguely similar, but not identical to the L<Event>
109	module.	122	module.
110		123
111	During the first call of any watcher-creation method, the module tries	124	During the first call of any watcher-creation method, the module tries
112	to detect the currently loaded event loop by probing whether one of the	125	to detect the currently loaded event loop by probing whether one of the
113	following modules is already loaded: L<EV>,	126	following modules is already loaded: L<EV>, L<AnyEvent::Loop>,
114	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	127	L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one
115	L<POE>. The first one found is used. If none are found, the module tries	128	found is used. If none are detected, the module tries to load the first
116	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	129	four modules in the order given; but note that if L<EV> is not
117	adaptor should always succeed) in the order given. The first one that can	130	available, the pure-perl L<AnyEvent::Loop> should always work, so
118	be successfully loaded will be used. If, after this, still none could be	131	the other two are not normally tried.
119	found, AnyEvent will fall back to a pure-perl event loop, which is not
120	very efficient, but should work everywhere.
121		132
122	Because AnyEvent first checks for modules that are already loaded, loading	133	Because AnyEvent first checks for modules that are already loaded, loading
123	an event model explicitly before first using AnyEvent will likely make	134	an event model explicitly before first using AnyEvent will likely make
124	that model the default. For example:	135	that model the default. For example:
125		136
…		…
127	use AnyEvent;	138	use AnyEvent;
128		139
129	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
130		141
131	The I<likely> means that, if any module loads another event model and	142	The I<likely> means that, if any module loads another event model and
132	starts using it, all bets are off. Maybe you should tell their authors to	143	starts using it, all bets are off - this case should be very rare though,
133	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
134		146
135	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called C<AnyEvent::Loop>. Like
136	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	148	other event modules you can load it explicitly and enjoy the high
137	explicitly and enjoy the high availability of that event loop :)	149	availability of that event loop :)
138		150
139	=head1 WATCHERS	151	=head1 WATCHERS
140		152
141	AnyEvent has the central concept of a I<watcher>, which is an object that	153	AnyEvent has the central concept of a I<watcher>, which is an object that
142	stores relevant data for each kind of event you are waiting for, such as	154	stores relevant data for each kind of event you are waiting for, such as
…		…
147	callback when the event occurs (of course, only when the event model	159	callback when the event occurs (of course, only when the event model
148	is in control).	160	is in control).
149		161
150	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
151	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<	163	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
152	callbacks must not C<die> >>. The former is good programming practise in	164	callbacks must not C<die> >>. The former is good programming practice in
153	Perl and the latter stems from the fact that exception handling differs	165	Perl and the latter stems from the fact that exception handling differs
154	widely between event loops.	166	widely between event loops.
155		167
156	To disable the watcher you have to destroy it (e.g. by setting the	168	To disable a watcher you have to destroy it (e.g. by setting the
157	variable you store it in to C<undef> or otherwise deleting all references	169	variable you store it in to C<undef> or otherwise deleting all references
158	to it).	170	to it).
159		171
160	All watchers are created by calling a method on the C<AnyEvent> class.	172	All watchers are created by calling a method on the C<AnyEvent> class.
161		173
162	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
163	example), or need to refer to their watcher object in other ways.	175	example), or need to refer to their watcher object in other ways.
164		176
165	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
166		178
167	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
168	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
169	undef $w;	181	undef $w;
170	});	182	});
…		…
172	Note that C<my $w; $w => combination. This is necessary because in Perl,	184	Note that C<my $w; $w => combination. This is necessary because in Perl,
173	my variables are only visible after the statement in which they are	185	my variables are only visible after the statement in which they are
174	declared.	186	declared.
175		187
176	=head2 I/O WATCHERS	188	=head2 I/O WATCHERS
		189
		190	$w = AnyEvent->io (
		191	fh => <filehandle_or_fileno>,
		192	poll => <"r" or "w">,
		193	cb => <callback>,
		194	);
177		195
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	196	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
180		198
181	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch	199	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
…		…
196		214
197	The I/O watcher might use the underlying file descriptor or a copy of it.	215	The I/O watcher might use the underlying file descriptor or a copy of it.
198	You must not close a file handle as long as any watcher is active on the	216	You must not close a file handle as long as any watcher is active on the
199	underlying file descriptor.	217	underlying file descriptor.
200		218
201	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
202	always use non-blocking calls when reading/writing from/to your file	220	always use non-blocking calls when reading/writing from/to your file
203	handles.	221	handles.
204		222
205	Example: wait for readability of STDIN, then read a line and disable the	223	Example: wait for readability of STDIN, then read a line and disable the
206	watcher.	224	watcher.
…		…
211	undef $w;	229	undef $w;
212	});	230	});
213		231
214	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
215		233
		234	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		235
		236	$w = AnyEvent->timer (
		237	after => <fractional_seconds>,
		238	interval => <fractional_seconds>,
		239	cb => <callback>,
		240	);
		241
216	You can create a time watcher by calling the C<< AnyEvent->timer >>	242	You can create a time watcher by calling the C<< AnyEvent->timer >>
217	method with the following mandatory arguments:	243	method with the following mandatory arguments:
218		244
219	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
220	supported) the callback should be invoked. C<cb> is the callback to invoke	246	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
222		248
223	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
224	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
225	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
226		252
227	The callback will normally be invoked once only. If you specify another	253	The callback will normally be invoked only once. If you specify another
228	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
229	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
230	seconds) after the first invocation. If C<interval> is specified with a	256	seconds) after the first invocation. If C<interval> is specified with a
231	false value, then it is treated as if it were missing.	257	false value, then it is treated as if it were not specified at all.
232		258
233	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
234	attempt is done to avoid timer drift in most backends, so the interval is	260	attempt is made to avoid timer drift in most backends, so the interval is
235	only approximate.	261	only approximate.
236		262
237	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
238		264
239	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
257		283
258	While most event loops expect timers to specified in a relative way, they	284	While most event loops expect timers to specified in a relative way, they
259	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
260	"jumps", for example, when ntp decides to set your clock backwards from	286	"jumps", for example, when ntp decides to set your clock backwards from
261	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to	287	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to
262	fire "after" a second might actually take six years to finally fire.	288	fire "after a second" might actually take six years to finally fire.
263		289
264	AnyEvent cannot compensate for this. The only event loop that is conscious	290	AnyEvent cannot compensate for this. The only event loop that is conscious
265	about these issues is L<EV>, which offers both relative (ev_timer, based	291	of these issues is L<EV>, which offers both relative (ev_timer, based
266	on true relative time) and absolute (ev_periodic, based on wallclock time)	292	on true relative time) and absolute (ev_periodic, based on wallclock time)
267	timers.	293	timers.
268		294
269	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
270	AnyEvent API.	296	AnyEvent API.
…		…
292	I<In almost all cases (in all cases if you don't care), this is the	318	I<In almost all cases (in all cases if you don't care), this is the
293	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
294		320
295	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
296	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
297	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
298		324
299	The rest of this section is only of relevance if you try to be very exact	325	The rest of this section is only of relevance if you try to be very exact
300	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
301		327
302	For a practical example of when these times differ, consider L<Event::Lib>	328	For a practical example of when these times differ, consider L<Event::Lib>
303	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
304		330
305	The event loop is running and has just invoked one of your callback at	331	The event loop is running and has just invoked one of your callbacks at
306	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
307	you wait a second by executing C<sleep 1> (blocking the process for a	333	you wait a second by executing C<sleep 1> (blocking the process for a
308	second) and then (at time=501) you create a relative timer that fires	334	second) and then (at time=501) you create a relative timer that fires
309	after three seconds.	335	after three seconds.
310		336
…		…
330	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	356	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
331	account.	357	account.
332		358
333	=item AnyEvent->now_update	359	=item AnyEvent->now_update
334		360
335	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache	361	Some event loops (such as L<EV> or L<AnyEvent::Loop>) cache the current
336	the current time for each loop iteration (see the discussion of L<<	362	time for each loop iteration (see the discussion of L<< AnyEvent->now >>,
337	AnyEvent->now >>, above).	363	above).
338		364
339	When a callback runs for a long time (or when the process sleeps), then	365	When a callback runs for a long time (or when the process sleeps), then
340	this "current" time will differ substantially from the real time, which	366	this "current" time will differ substantially from the real time, which
341	might affect timers and time-outs.	367	might affect timers and time-outs.
342		368
343	When this is the case, you can call this method, which will update the	369	When this is the case, you can call this method, which will update the
344	event loop's idea of "current time".	370	event loop's idea of "current time".
345		371
		372	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		373	when mod_perl executes the script, then the event loop will have the wrong
		374	idea about the "current time" (being potentially far in the past, when the
		375	script ran the last time). In that case you should arrange a call to C<<
		376	AnyEvent->now_update >> each time the web server process wakes up again
		377	(e.g. at the start of your script, or in a handler).
		378
346	Note that updating the time I<might> cause some events to be handled.	379	Note that updating the time I<might> cause some events to be handled.
347		380
348	=back	381	=back
349		382
350	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351		386
352	You can watch for signals using a signal watcher, C<signal> is the signal	387	You can watch for signals using a signal watcher, C<signal> is the signal
353	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	388	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
355		390
…		…
368		403
369	This watcher might use C<%SIG> (depending on the event loop used),	404	This watcher might use C<%SIG> (depending on the event loop used),
370	so programs overwriting those signals directly will likely not work	405	so programs overwriting those signals directly will likely not work
371	correctly.	406	correctly.
372		407
		408	Example: exit on SIGINT
		409
		410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling) or
		421	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		422	latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
		429	=head3 Signal Races, Delays and Workarounds
		430
373	Also note that many event loops (e.g. Glib, Tk, Qt, IO::Async) do not	431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
374	support attaching callbacks to signals, which is a pity, as you cannot do	432	callbacks to signals in a generic way, which is a pity, as you cannot
375	race-free signal handling in perl. AnyEvent will try to do it's best, but	433	do race-free signal handling in perl, requiring C libraries for
		434	this. AnyEvent will try to do its best, which means in some cases,
376	in some cases, signals will be delayed. The maximum time a signal might	435	signals will be delayed. The maximum time a signal might be delayed is
377	be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10	436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
378	seconds). This variable can be changed only before the first signal	437	variable can be changed only before the first signal watcher is created,
379	watcher is created, and should be left alone otherwise. Higher values	438	and should be left alone otherwise. This variable determines how often
		439	AnyEvent polls for signals (in case a wake-up was missed). Higher values
380	will cause fewer spurious wake-ups, which is better for power and CPU	440	will cause fewer spurious wake-ups, which is better for power and CPU
		441	saving.
		442
381	saving. All these problems can be avoided by installing the optional	443	All these problems can be avoided by installing the optional
382	L<Async::Interrupt> module.	444	L<Async::Interrupt> module, which works with most event loops. It will not
383		445	work with inherently broken event loops such as L<Event> or L<Event::Lib>
384	Example: exit on SIGINT	446	(and not with L<POE> currently, as POE does its own workaround with
385		447	one-second latency). For those, you just have to suffer the delays.
386	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
387		448
388	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
389		450
		451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		452
390	You can also watch on a child process exit and catch its exit status.	453	You can also watch for a child process exit and catch its exit status.
391		454
392	The child process is specified by the C<pid> argument (if set to C<0>, it	455	The child process is specified by the C<pid> argument (on some backends,
393	watches for any child process exit). The watcher will triggered only when	456	using C<0> watches for any child process exit, on others this will
394	the child process has finished and an exit status is available, not on	457	croak). The watcher will be triggered only when the child process has
395	any trace events (stopped/continued).	458	finished and an exit status is available, not on any trace events
		459	(stopped/continued).
396		460
397	The callback will be called with the pid and exit status (as returned by	461	The callback will be called with the pid and exit status (as returned by
398	waitpid), so unlike other watcher types, you I<can> rely on child watcher	462	waitpid), so unlike other watcher types, you I<can> rely on child watcher
399	callback arguments.	463	callback arguments.
400		464
…		…
418	thing in an AnyEvent program, you I<have> to create at least one	482	thing in an AnyEvent program, you I<have> to create at least one
419	watcher before you C<fork> the child (alternatively, you can call	483	watcher before you C<fork> the child (alternatively, you can call
420	C<AnyEvent::detect>).	484	C<AnyEvent::detect>).
421		485
422	As most event loops do not support waiting for child events, they will be	486	As most event loops do not support waiting for child events, they will be
423	emulated by AnyEvent in most cases, in which the latency and race problems	487	emulated by AnyEvent in most cases, in which case the latency and race
424	mentioned in the description of signal watchers apply.	488	problems mentioned in the description of signal watchers apply.
425		489
426	Example: fork a process and wait for it	490	Example: fork a process and wait for it
427		491
428	my $done = AnyEvent->condvar;	492	my $done = AnyEvent->condvar;
429		493
…		…
441	# do something else, then wait for process exit	505	# do something else, then wait for process exit
442	$done->recv;	506	$done->recv;
443		507
444	=head2 IDLE WATCHERS	508	=head2 IDLE WATCHERS
445		509
446	Sometimes there is a need to do something, but it is not so important	510	$w = AnyEvent->idle (cb => <callback>);
447	to do it instantly, but only when there is nothing better to do. This
448	"nothing better to do" is usually defined to be "no other events need
449	attention by the event loop".
450		511
451	Idle watchers ideally get invoked when the event loop has nothing	512	This will repeatedly invoke the callback after the process becomes idle,
452	better to do, just before it would block the process to wait for new	513	until either the watcher is destroyed or new events have been detected.
453	events. Instead of blocking, the idle watcher is invoked.
454		514
455	Most event loops unfortunately do not really support idle watchers (only	515	Idle watchers are useful when there is a need to do something, but it
		516	is not so important (or wise) to do it instantly. The callback will be
		517	invoked only when there is "nothing better to do", which is usually
		518	defined as "all outstanding events have been handled and no new events
		519	have been detected". That means that idle watchers ideally get invoked
		520	when the event loop has just polled for new events but none have been
		521	detected. Instead of blocking to wait for more events, the idle watchers
		522	will be invoked.
		523
		524	Unfortunately, most event loops do not really support idle watchers (only
456	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	525	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
457	will simply call the callback "from time to time".	526	will simply call the callback "from time to time".
458		527
459	Example: read lines from STDIN, but only process them when the	528	Example: read lines from STDIN, but only process them when the
460	program is otherwise idle:	529	program is otherwise idle:
…		…
476	});	545	});
477	});	546	});
478		547
479	=head2 CONDITION VARIABLES	548	=head2 CONDITION VARIABLES
480		549
		550	$cv = AnyEvent->condvar;
		551
		552	$cv->send (<list>);
		553	my @res = $cv->recv;
		554
481	If you are familiar with some event loops you will know that all of them	555	If you are familiar with some event loops you will know that all of them
482	require you to run some blocking "loop", "run" or similar function that	556	require you to run some blocking "loop", "run" or similar function that
483	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
484		558
485	AnyEvent is slightly different: it expects somebody else to run the event	559	AnyEvent is slightly different: it expects somebody else to run the event
486	loop and will only block when necessary (usually when told by the user).	560	loop and will only block when necessary (usually when told by the user).
487		561
488	The instrument to do that is called a "condition variable", so called	562	The tool to do that is called a "condition variable", so called because
489	because they represent a condition that must become true.	563	they represent a condition that must become true.
490		564
491	Now is probably a good time to look at the examples further below.	565	Now is probably a good time to look at the examples further below.
492		566
493	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
494	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
…		…
499	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
500	by calling the C<send> method (or calling the condition variable as if it	574	by calling the C<send> method (or calling the condition variable as if it
501	were a callback, read about the caveats in the description for the C<<	575	were a callback, read about the caveats in the description for the C<<
502	->send >> method).	576	->send >> method).
503		577
504	Condition variables are similar to callbacks, except that you can	578	Since condition variables are the most complex part of the AnyEvent API, here are
505	optionally wait for them. They can also be called merge points - points	579	some different mental models of what they are - pick the ones you can connect to:
506	in time where multiple outstanding events have been processed. And yet	580
507	another way to call them is transactions - each condition variable can be	581	=over 4
508	used to represent a transaction, which finishes at some point and delivers	582
509	a result.	583	=item * Condition variables are like callbacks - you can call them (and pass them instead
		584	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		585
		586	=item * Condition variables are signals - one side can emit or send them,
		587	the other side can wait for them, or install a handler that is called when
		588	the signal fires.
		589
		590	=item * Condition variables are like "Merge Points" - points in your program
		591	where you merge multiple independent results/control flows into one.
		592
		593	=item * Condition variables represent a transaction - functions that start
		594	some kind of transaction can return them, leaving the caller the choice
		595	between waiting in a blocking fashion, or setting a callback.
		596
		597	=item * Condition variables represent future values, or promises to deliver
		598	some result, long before the result is available.
		599
		600	=back
510		601
511	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
512	for example, if you write a module that does asynchronous http requests,	603	for example, if you write a module that does asynchronous http requests,
513	then a condition variable would be the ideal candidate to signal the	604	then a condition variable would be the ideal candidate to signal the
514	availability of results. The user can either act when the callback is	605	availability of results. The user can either act when the callback is
…		…
527		618
528	Condition variables are represented by hash refs in perl, and the keys	619	Condition variables are represented by hash refs in perl, and the keys
529	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing	620	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
530	easy (it is often useful to build your own transaction class on top of	621	easy (it is often useful to build your own transaction class on top of
531	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call	622	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
532	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
533		624
534	There are two "sides" to a condition variable - the "producer side" which	625	There are two "sides" to a condition variable - the "producer side" which
535	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
536	for the send to occur.	627	for the send to occur.
537		628
538	Example: wait for a timer.	629	Example: wait for a timer.
539		630
540	# wait till the result is ready	631	# condition: "wait till the timer is fired"
541	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
542		633
543	# do something such as adding a timer	634	# create the timer - we could wait for, say
544	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
545	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
546	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
547	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
548	after => 1,	639	after => 1,
549	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
550	);	641	);
551		642
552	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
553	# calls -<send	644	# calls ->send
554	$result_ready->recv;	645	$timer_fired->recv;
555		646
556	Example: wait for a timer, but take advantage of the fact that condition	647	Example: wait for a timer, but take advantage of the fact that condition
557	variables are also callable directly.	648	variables are also callable directly.
558		649
559	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
…		…
602	they were a code reference). Calling them directly is the same as calling	693	they were a code reference). Calling them directly is the same as calling
603	C<send>.	694	C<send>.
604		695
605	=item $cv->croak ($error)	696	=item $cv->croak ($error)
606		697
607	Similar to send, but causes all call's to C<< ->recv >> to invoke	698	Similar to send, but causes all calls to C<< ->recv >> to invoke
608	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
609		700
610	This can be used to signal any errors to the condition variable	701	This can be used to signal any errors to the condition variable
611	user/consumer. Doing it this way instead of calling C<croak> directly	702	user/consumer. Doing it this way instead of calling C<croak> directly
612	delays the error detetcion, but has the overwhelmign advantage that it	703	delays the error detection, but has the overwhelming advantage that it
613	diagnoses the error at the place where the result is expected, and not	704	diagnoses the error at the place where the result is expected, and not
614	deep in some event clalback without connection to the actual code causing	705	deep in some event callback with no connection to the actual code causing
615	the problem.	706	the problem.
616		707
617	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
618		709
619	=item $cv->end	710	=item $cv->end
…		…
622	one. For example, a function that pings many hosts in parallel might want	713	one. For example, a function that pings many hosts in parallel might want
623	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
624		715
625	Every call to C<< ->begin >> will increment a counter, and every call to	716	Every call to C<< ->begin >> will increment a counter, and every call to
626	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	717	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
627	>>, the (last) callback passed to C<begin> will be executed. That callback	718	>>, the (last) callback passed to C<begin> will be executed, passing the
628	is I<supposed> to call C<< ->send >>, but that is not required. If no	719	condvar as first argument. That callback is I<supposed> to call C<< ->send
629	callback was set, C<send> will be called without any arguments.	720	>>, but that is not required. If no group callback was set, C<send> will
		721	be called without any arguments.
630		722
631	You can think of C<< $cv->send >> giving you an OR condition (one call	723	You can think of C<< $cv->send >> giving you an OR condition (one call
632	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND	724	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
633	condition (all C<begin> calls must be C<end>'ed before the condvar sends).	725	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
634		726
…		…
656	one call to C<begin>, so the condvar waits for all calls to C<end> before	748	one call to C<begin>, so the condvar waits for all calls to C<end> before
657	sending.	749	sending.
658		750
659	The ping example mentioned above is slightly more complicated, as the	751	The ping example mentioned above is slightly more complicated, as the
660	there are results to be passwd back, and the number of tasks that are	752	there are results to be passwd back, and the number of tasks that are
661	begung can potentially be zero:	753	begun can potentially be zero:
662		754
663	my $cv = AnyEvent->condvar;	755	my $cv = AnyEvent->condvar;
664		756
665	my %result;	757	my %result;
666	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
667		759
668	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
669	$cv->begin;	761	$cv->begin;
670	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
671	$result{$host} = ...;	763	$result{$host} = ...;
…		…
687	to be called once the counter reaches C<0>, and second, it ensures that	779	to be called once the counter reaches C<0>, and second, it ensures that
688	C<send> is called even when C<no> hosts are being pinged (the loop	780	C<send> is called even when C<no> hosts are being pinged (the loop
689	doesn't execute once).	781	doesn't execute once).
690		782
691	This is the general pattern when you "fan out" into multiple (but	783	This is the general pattern when you "fan out" into multiple (but
692	potentially none) subrequests: use an outer C<begin>/C<end> pair to set	784	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
693	the callback and ensure C<end> is called at least once, and then, for each	785	the callback and ensure C<end> is called at least once, and then, for each
694	subrequest you start, call C<begin> and for each subrequest you finish,	786	subrequest you start, call C<begin> and for each subrequest you finish,
695	call C<end>.	787	call C<end>.
696		788
697	=back	789	=back
…		…
704	=over 4	796	=over 4
705		797
706	=item $cv->recv	798	=item $cv->recv
707		799
708	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
709	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
710	normally.	802	normally.
711		803
712	You can only wait once on a condition - additional calls are valid but	804	You can only wait once on a condition - additional calls are valid but
713	will return immediately.	805	will return immediately.
714		806
…		…
731	caller decide whether the call will block or not (for example, by coupling	823	caller decide whether the call will block or not (for example, by coupling
732	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
733	callbacks so the caller knows that getting the result will not block,	825	callbacks so the caller knows that getting the result will not block,
734	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
735		827
736	You can ensure that C<< -recv >> never blocks by setting a callback and	828	You can ensure that C<< ->recv >> never blocks by setting a callback and
737	only calling C<< ->recv >> from within that callback (or at a later	829	only calling C<< ->recv >> from within that callback (or at a later
738	time). This will work even when the event loop does not support blocking	830	time). This will work even when the event loop does not support blocking
739	waits otherwise.	831	waits otherwise.
740		832
741	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
747		839
748	This is a mutator function that returns the callback set and optionally	840	This is a mutator function that returns the callback set and optionally
749	replaces it before doing so.	841	replaces it before doing so.
750		842
751	The callback will be called when the condition becomes "true", i.e. when	843	The callback will be called when the condition becomes "true", i.e. when
752	C<send> or C<croak> are called, with the only argument being the condition	844	C<send> or C<croak> are called, with the only argument being the
753	variable itself. Calling C<recv> inside the callback or at any later time	845	condition variable itself. If the condition is already true, the
754	is guaranteed not to block.	846	callback is called immediately when it is set. Calling C<recv> inside
		847	the callback or at any later time is guaranteed not to block.
755		848
756	=back	849	=back
757		850
758	=head1 SUPPORTED EVENT LOOPS/BACKENDS	851	=head1 SUPPORTED EVENT LOOPS/BACKENDS
759		852
…		…
762	=over 4	855	=over 4
763		856
764	=item Backends that are autoprobed when no other event loop can be found.	857	=item Backends that are autoprobed when no other event loop can be found.
765		858
766	EV is the preferred backend when no other event loop seems to be in	859	EV is the preferred backend when no other event loop seems to be in
767	use. If EV is not installed, then AnyEvent will try Event, and, failing	860	use. If EV is not installed, then AnyEvent will fall back to its own
768	that, will fall back to its own pure-perl implementation, which is	861	pure-perl implementation, which is available everywhere as it comes with
769	available everywhere as it comes with AnyEvent itself.	862	AnyEvent itself.
770		863
771	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	864	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
772	AnyEvent::Impl::Event based on Event, very stable, few glitches.
773	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	865	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
774		866
775	=item Backends that are transparently being picked up when they are used.	867	=item Backends that are transparently being picked up when they are used.
776		868
777	These will be used when they are currently loaded when the first watcher	869	These will be used if they are already loaded when the first watcher
778	is created, in which case it is assumed that the application is using	870	is created, in which case it is assumed that the application is using
779	them. This means that AnyEvent will automatically pick the right backend	871	them. This means that AnyEvent will automatically pick the right backend
780	when the main program loads an event module before anything starts to	872	when the main program loads an event module before anything starts to
781	create watchers. Nothing special needs to be done by the main program.	873	create watchers. Nothing special needs to be done by the main program.
782		874
		875	AnyEvent::Impl::Event based on Event, very stable, few glitches.
783	AnyEvent::Impl::Glib based on Glib, slow but very stable.	876	AnyEvent::Impl::Glib based on Glib, slow but very stable.
784	AnyEvent::Impl::Tk based on Tk, very broken.	877	AnyEvent::Impl::Tk based on Tk, very broken.
785	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	878	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
786	AnyEvent::Impl::POE based on POE, very slow, some limitations.	879	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		880	AnyEvent::Impl::Irssi used when running within irssi.
		881	AnyEvent::Impl::IOAsync based on IO::Async.
		882	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
		883	AnyEvent::Impl::FLTK2 based on FLTK (fltk 2 binding).
787		884
788	=item Backends with special needs.	885	=item Backends with special needs.
789		886
790	Qt requires the Qt::Application to be instantiated first, but will	887	Qt requires the Qt::Application to be instantiated first, but will
791	otherwise be picked up automatically. As long as the main program	888	otherwise be picked up automatically. As long as the main program
792	instantiates the application before any AnyEvent watchers are created,	889	instantiates the application before any AnyEvent watchers are created,
793	everything should just work.	890	everything should just work.
794		891
795	AnyEvent::Impl::Qt based on Qt.	892	AnyEvent::Impl::Qt based on Qt.
796		893
797	Support for IO::Async can only be partial, as it is too broken and
798	architecturally limited to even support the AnyEvent API. It also
799	is the only event loop that needs the loop to be set explicitly, so
800	it can only be used by a main program knowing about AnyEvent. See
801	L<AnyEvent::Impl::Async> for the gory details.
802
803	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
804
805	=item Event loops that are indirectly supported via other backends.	894	=item Event loops that are indirectly supported via other backends.
806		895
807	Some event loops can be supported via other modules:	896	Some event loops can be supported via other modules:
808		897
809	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.	898	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
…		…
834	Contains C<undef> until the first watcher is being created, before the	923	Contains C<undef> until the first watcher is being created, before the
835	backend has been autodetected.	924	backend has been autodetected.
836		925
837	Afterwards it contains the event model that is being used, which is the	926	Afterwards it contains the event model that is being used, which is the
838	name of the Perl class implementing the model. This class is usually one	927	name of the Perl class implementing the model. This class is usually one
839	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the	928	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
840	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it	929	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
841	will be C<urxvt::anyevent>).	930	will be C<urxvt::anyevent>).
842		931
843	=item AnyEvent::detect	932	=item AnyEvent::detect
844		933
845	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	934	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
846	if necessary. You should only call this function right before you would	935	if necessary. You should only call this function right before you would
847	have created an AnyEvent watcher anyway, that is, as late as possible at	936	have created an AnyEvent watcher anyway, that is, as late as possible at
848	runtime, and not e.g. while initialising of your module.	937	runtime, and not e.g. during initialisation of your module.
849		938
850	If you need to do some initialisation before AnyEvent watchers are	939	If you need to do some initialisation before AnyEvent watchers are
851	created, use C<post_detect>.	940	created, use C<post_detect>.
852		941
853	=item $guard = AnyEvent::post_detect { BLOCK }	942	=item $guard = AnyEvent::post_detect { BLOCK }
854		943
855	Arranges for the code block to be executed as soon as the event model is	944	Arranges for the code block to be executed as soon as the event model is
856	autodetected (or immediately if this has already happened).	945	autodetected (or immediately if that has already happened).
857		946
858	The block will be executed I<after> the actual backend has been detected	947	The block will be executed I<after> the actual backend has been detected
859	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	948	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
860	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	949	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
861	other initialisations - see the sources of L<AnyEvent::Strict> or	950	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
865	event module detection too early, for example, L<AnyEvent::AIO> creates	954	event module detection too early, for example, L<AnyEvent::AIO> creates
866	and installs the global L<IO::AIO> watcher in a C<post_detect> block to	955	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
867	avoid autodetecting the event module at load time.	956	avoid autodetecting the event module at load time.
868		957
869	If called in scalar or list context, then it creates and returns an object	958	If called in scalar or list context, then it creates and returns an object
870	that automatically removes the callback again when it is destroyed. See	959	that automatically removes the callback again when it is destroyed (or
		960	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
871	L<Coro::BDB> for a case where this is useful.	961	a case where this is useful.
		962
		963	Example: Create a watcher for the IO::AIO module and store it in
		964	C<$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 ||= $guard;
872		978
873	=item @AnyEvent::post_detect	979	=item @AnyEvent::post_detect
874		980
875	If there are any code references in this array (you can C<push> to it	981	If there are any code references in this array (you can C<push> to it
876	before or after loading AnyEvent), then they will called directly after	982	before or after loading AnyEvent), then they will be called directly
877	the event loop has been chosen.	983	after the event loop has been chosen.
878		984
879	You should check C<$AnyEvent::MODEL> before adding to this array, though:	985	You should check C<$AnyEvent::MODEL> before adding to this array, though:
880	if it is defined then the event loop has already been detected, and the	986	if it is defined then the event loop has already been detected, and the
881	array will be ignored.	987	array will be ignored.
882		988
883	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	989	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
884	it,as it takes care of these details.	990	it, as it takes care of these details.
885		991
886	This variable is mainly useful for modules that can do something useful	992	This variable is mainly useful for modules that can do something useful
887	when AnyEvent is used and thus want to know when it is initialised, but do	993	when AnyEvent is used and thus want to know when it is initialised, but do
888	not need to even load it by default. This array provides the means to hook	994	not need to even load it by default. This array provides the means to hook
889	into AnyEvent passively, without loading it.	995	into AnyEvent passively, without loading it.
890		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;
		1049
891	=back	1050	=back
892		1051
893	=head1 WHAT TO DO IN A MODULE	1052	=head1 WHAT TO DO IN A MODULE
894		1053
895	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1054	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
905	because it will stall the whole program, and the whole point of using	1064	because it will stall the whole program, and the whole point of using
906	events is to stay interactive.	1065	events is to stay interactive.
907		1066
908	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
909	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
910	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 >>
911	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).
912		1071
913	=head1 WHAT TO DO IN THE MAIN PROGRAM	1072	=head1 WHAT TO DO IN THE MAIN PROGRAM
914		1073
915	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
916	dictate which event model to use.	1075	dictate which event model to use.
917		1076
918	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
919	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
920	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.
921		1082
922	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
923	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
924	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
925	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
926	modules might create watchers when they are loaded, and AnyEvent will	1087	modules might create watchers when they are loaded, and AnyEvent will
927	decide on the event model to use as soon as it creates watchers, and it	1088	decide on the event model to use as soon as it creates watchers, and it
928	might chose the wrong one unless you load the correct one yourself.	1089	might choose the wrong one unless you load the correct one yourself.
929		1090
930	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
931	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1092	C<AnyEvent::Loop> module, which gives you similar behaviour
932	everywhere, but letting AnyEvent chose the model is generally better.	1093	everywhere, but letting AnyEvent chose the model is generally better.
933		1094
934	=head2 MAINLOOP EMULATION	1095	=head2 MAINLOOP EMULATION
935		1096
936	Sometimes (often for short test scripts, or even standalone programs who	1097	Sometimes (often for short test scripts, or even standalone programs who
…		…
951	=head1 OTHER MODULES	1112	=head1 OTHER MODULES
952		1113
953	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
954	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1115	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
955	modules and other event loops in the same program. Some of the modules	1116	modules and other event loops in the same program. Some of the modules
956	come with AnyEvent, most are available via CPAN.	1117	come as part of AnyEvent, the others are available via CPAN.
957		1118
958	=over 4	1119	=over 4
959		1120
960	=item L<AnyEvent::Util>	1121	=item L<AnyEvent::Util>
961		1122
962	Contains various utility functions that replace often-used but blocking	1123	Contains various utility functions that replace often-used blocking
963	functions such as C<inet_aton> by event-/callback-based versions.	1124	functions such as C<inet_aton> with event/callback-based versions.
964		1125
965	=item L<AnyEvent::Socket>	1126	=item L<AnyEvent::Socket>
966		1127
967	Provides various utility functions for (internet protocol) sockets,	1128	Provides various utility functions for (internet protocol) sockets,
968	addresses and name resolution. Also functions to create non-blocking tcp	1129	addresses and name resolution. Also functions to create non-blocking tcp
…		…
970		1131
971	=item L<AnyEvent::Handle>	1132	=item L<AnyEvent::Handle>
972		1133
973	Provide read and write buffers, manages watchers for reads and writes,	1134	Provide read and write buffers, manages watchers for reads and writes,
974	supports raw and formatted I/O, I/O queued and fully transparent and	1135	supports raw and formatted I/O, I/O queued and fully transparent and
975	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1136	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
976		1137
977	=item L<AnyEvent::DNS>	1138	=item L<AnyEvent::DNS>
978		1139
979	Provides rich asynchronous DNS resolver capabilities.	1140	Provides rich asynchronous DNS resolver capabilities.
980		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
981	=item L<AnyEvent::HTTP>	1165	=item L<AnyEvent::DBI>
982		1166
983	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,
984	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.
985		1176
986	=item L<AnyEvent::HTTPD>	1177	=item L<AnyEvent::HTTPD>
987		1178
988	Provides a simple web application server framework.	1179	A simple embedded webserver.
989		1180
990	=item L<AnyEvent::FastPing>	1181	=item L<AnyEvent::FastPing>
991		1182
992	The fastest ping in the west.	1183	The fastest ping in the west.
993
994	=item L<AnyEvent::DBI>
995
996	Executes L<DBI> requests asynchronously in a proxy process.
997
998	=item L<AnyEvent::AIO>
999
1000	Truly asynchronous I/O, should be in the toolbox of every event
1001	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1002	together.
1003
1004	=item L<AnyEvent::BDB>
1005
1006	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1007	L<BDB> and AnyEvent together.
1008
1009	=item L<AnyEvent::GPSD>
1010
1011	A non-blocking interface to gpsd, a daemon delivering GPS information.
1012
1013	=item L<AnyEvent::IRC>
1014
1015	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1016
1017	=item L<AnyEvent::XMPP>
1018
1019	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1020	Net::XMPP2>.
1021
1022	=item L<AnyEvent::IGS>
1023
1024	A non-blocking interface to the Internet Go Server protocol (used by
1025	L<App::IGS>).
1026
1027	=item L<Net::FCP>
1028
1029	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1030	of AnyEvent.
1031
1032	=item L<Event::ExecFlow>
1033
1034	High level API for event-based execution flow control.
1035		1184
1036	=item L<Coro>	1185	=item L<Coro>
1037		1186
1038	Has special support for AnyEvent via L<Coro::AnyEvent>.	1187	Has special support for AnyEvent via L<Coro::AnyEvent>.
1039		1188
…		…
1043		1192
1044	package AnyEvent;	1193	package AnyEvent;
1045		1194
1046	# basically a tuned-down version of common::sense	1195	# basically a tuned-down version of common::sense
1047	sub common_sense {	1196	sub common_sense {
1048	# no warnings	1197	# from common:.sense 3.4
1049	${^WARNING_BITS} ^= ${^WARNING_BITS};	1198	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1050	# use strict vars subs	1199	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1051	$^H |= 0x00000600;	1200	$^H |= 0x00000600;
1052	}	1201	}
1053		1202
1054	BEGIN { AnyEvent::common_sense }	1203	BEGIN { AnyEvent::common_sense }
1055		1204
1056	use Carp ();	1205	use Carp ();
1057		1206
1058	our $VERSION = 4.83;	1207	our $VERSION = '5.34';
1059	our $MODEL;	1208	our $MODEL;
1060		1209
1061	our $AUTOLOAD;
1062	our @ISA;	1210	our @ISA;
1063		1211
1064	our @REGISTRY;	1212	our @REGISTRY;
1065		1213
1066	our $WIN32;
1067
1068	our $VERBOSE;	1214	our $VERBOSE;
1069		1215
1070	BEGIN {	1216	BEGIN {
1071	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1217	require "AnyEvent/constants.pl";
		1218
1072	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1219	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1073		1220
1074	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1221	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1075	if ${^TAINT};	1222	if ${^TAINT};
1076		1223
1077	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1224	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
…		…
1087	$PROTOCOL{$_} = ++$idx	1234	$PROTOCOL{$_} = ++$idx
1088	for reverse split /\s*,\s*/,	1235	for reverse split /\s*,\s*/,
1089	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1236	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1090	}	1237	}
1091		1238
		1239	our @post_detect;
		1240
		1241	sub post_detect(&) {
		1242	my ($cb) = @_;
		1243
		1244	push @post_detect, $cb;
		1245
		1246	defined wantarray
		1247	? bless \$cb, "AnyEvent::Util::postdetect"
		1248	: ()
		1249	}
		1250
		1251	sub AnyEvent::Util::postdetect::DESTROY {
		1252	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1253	}
		1254
		1255	our $POSTPONE_W;
		1256	our @POSTPONE;
		1257
		1258	sub _postpone_exec {
		1259	undef $POSTPONE_W;
		1260
		1261	&{ shift @POSTPONE }
		1262	while @POSTPONE;
		1263	}
		1264
		1265	sub postpone(&) {
		1266	push @POSTPONE, shift;
		1267
		1268	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1269
		1270	()
		1271	}
		1272
1092	my @models = (	1273	our @models = (
1093	[EV:: => AnyEvent::Impl::EV::],	1274	[EV:: => AnyEvent::Impl::EV:: , 1],
1094	[Event:: => AnyEvent::Impl::Event::],	1275	[AnyEvent::Loop:: => AnyEvent::Impl::Perl:: , 1],
1095	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
1096	# everything below here will not be autoprobed	1276	# everything below here will not (normally) be autoprobed
1097	# as the pureperl backend should work everywhere	1277	# as the pure perl backend should work everywhere
1098	# and is usually faster	1278	# and is usually faster
		1279	[Event:: => AnyEvent::Impl::Event::, 1],
1099	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1280	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1100	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1281	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1282	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1101	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1283	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1102	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1284	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1103	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1285	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1104	[Wx:: => AnyEvent::Impl::POE::],	1286	[Wx:: => AnyEvent::Impl::POE::],
1105	[Prima:: => AnyEvent::Impl::POE::],	1287	[Prima:: => AnyEvent::Impl::POE::],
1106	# IO::Async is just too broken - we would need workarounds for its	1288	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1107	# byzantine signal and broken child handling, among others.	1289	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1108	# IO::Async is rather hard to detect, as it doesn't have any	1290	[FLTK:: => AnyEvent::Impl::FLTK2::],
1109	# obvious default class.
1110	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1111	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1112	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1113	);	1291	);
1114		1292
1115	our %method = map +($_ => 1),	1293	# all autoloaded methods reserve the complete glob, not just the method slot.
		1294	# due to bugs in perls method cache implementation.
1116	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1295	our @methods = qw(io timer time now now_update signal child idle condvar);
1117		1296
1118	our @post_detect;
1119
1120	sub post_detect(&) {	1297	sub detect() {
1121	my ($cb) = @_;	1298	local $!; # for good measure
		1299	local $SIG{__DIE__}; # we use eval
1122		1300
1123	if ($MODEL) {	1301	# free some memory
1124	$cb->();	1302	*detect = sub () { $MODEL };
		1303	# undef &func doesn't correctly update the method cache. grmbl.
		1304	# so we delete the whole glob. grmbl.
		1305	# otoh, perl doesn't let me undef an active usb, but it lets me free
		1306	# a glob with an active sub. hrm. i hope it works, but perl is
		1307	# usually buggy in this department. sigh.
		1308	delete @{"AnyEvent::"}{@methods};
		1309	undef @methods;
1125		1310
1126	1	1311	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1312	my $model = $1;
		1313	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1314	if (eval "require $model") {
		1315	$MODEL = $model;
		1316	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1127	} else {	1317	} else {
1128	push @post_detect, $cb;	1318	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1129		1319	}
1130	defined wantarray
1131	? bless \$cb, "AnyEvent::Util::postdetect"
1132	: ()
1133	}	1320	}
1134	}
1135		1321
1136	sub AnyEvent::Util::postdetect::DESTROY {	1322	# check for already loaded models
1137	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1138	}
1139
1140	sub detect() {
1141	unless ($MODEL) {	1323	unless ($MODEL) {
1142	local $SIG{__DIE__};	1324	for (@REGISTRY, @models) {
1143		1325	my ($package, $model) = @$_;
1144	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1326	if (${"$package\::VERSION"} > 0) {
1145	my $model = "AnyEvent::Impl::$1";
1146	if (eval "require $model") {	1327	if (eval "require $model") {
1147	$MODEL = $model;	1328	$MODEL = $model;
1148	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1329	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1149	} else {	1330	last;
1150	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1331	}
1151	}	1332	}
1152	}	1333	}
1153		1334
1154	# check for already loaded models
1155	unless ($MODEL) {	1335	unless ($MODEL) {
		1336	# try to autoload a model
1156	for (@REGISTRY, @models) {	1337	for (@REGISTRY, @models) {
1157	my ($package, $model) = @$_;	1338	my ($package, $model, $autoload) = @$_;
		1339	if (
		1340	$autoload
		1341	and eval "require $package"
1158	if (${"$package\::VERSION"} > 0) {	1342	and ${"$package\::VERSION"} > 0
1159	if (eval "require $model") {	1343	and eval "require $model"
		1344	) {
1160	$MODEL = $model;	1345	$MODEL = $model;
1161	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;	1346	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1162	last;	1347	last;
1163	}
1164	}	1348	}
1165	}	1349	}
1166		1350
1167	unless ($MODEL) {
1168	# try to load a model
1169
1170	for (@REGISTRY, @models) {
1171	my ($package, $model) = @$_;
1172	if (eval "require $package"
1173	and ${"$package\::VERSION"} > 0
1174	and eval "require $model") {
1175	$MODEL = $model;
1176	warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1177	last;
1178	}
1179	}
1180
1181	$MODEL	1351	$MODEL
1182	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1352	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?\n";
1183	}
1184	}	1353	}
1185
1186	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1187
1188	unshift @ISA, $MODEL;
1189
1190	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1191
1192	(shift @post_detect)->() while @post_detect;
1193	}	1354	}
1194		1355
		1356	# free memory only needed for probing
		1357	undef @models;
		1358	undef @REGISTRY;
		1359
		1360	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1361	unshift @ISA, $MODEL;
		1362
		1363	# now nuke some methods that are overridden by the backend.
		1364	# SUPER usage is not allowed in these.
		1365	for (qw(time signal child idle)) {
		1366	undef &{"AnyEvent::Base::$_"}
		1367	if defined &{"$MODEL\::$_"};
		1368	}
		1369
		1370	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1371	require AnyEvent::Strict;
		1372	}
		1373
		1374	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1375	require AnyEvent::Debug;
		1376	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1377	}
		1378
		1379	if (exists $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1380	require AnyEvent::Socket;
		1381	require AnyEvent::Debug;
		1382
		1383	my ($host, $service) = AnyEvent::Socket::parse_hostport ($ENV{PERL_ANYEVENT_DEBUG_SHELL});
		1384	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1385	}
		1386
		1387	(shift @post_detect)->() while @post_detect;
		1388	undef @post_detect;
		1389
		1390	*post_detect = sub(&) {
		1391	shift->();
		1392
		1393	undef
		1394	};
		1395
1195	$MODEL	1396	$MODEL
1196	}	1397	}
1197		1398
1198	sub AUTOLOAD {	1399	for my $name (@methods) {
1199	(my $func = $AUTOLOAD) =~ s/.*://;	1400	*$name = sub {
1200		1401	detect;
1201	$method{$func}	1402	# we use goto because
1202	or Carp::croak "$func: not a valid method for AnyEvent objects";	1403	# a) it makes the thunk more transparent
1203		1404	# b) it allows us to delete the thunk later
1204	detect unless $MODEL;	1405	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1205		1406	};
1206	my $class = shift;
1207	$class->$func (@_);
1208	}	1407	}
1209		1408
1210	# utility function to dup a filehandle. this is used by many backends	1409	# utility function to dup a filehandle. this is used by many backends
1211	# to support binding more than one watcher per filehandle (they usually	1410	# to support binding more than one watcher per filehandle (they usually
1212	# allow only one watcher per fd, so we dup it to get a different one).	1411	# allow only one watcher per fd, so we dup it to get a different one).
…		…
1222	# we assume CLOEXEC is already set by perl in all important cases	1421	# we assume CLOEXEC is already set by perl in all important cases
1223		1422
1224	($fh2, $rw)	1423	($fh2, $rw)
1225	}	1424	}
1226		1425
		1426	=head1 SIMPLIFIED AE API
		1427
		1428	Starting with version 5.0, AnyEvent officially supports a second, much
		1429	simpler, API that is designed to reduce the calling, typing and memory
		1430	overhead by using function call syntax and a fixed number of parameters.
		1431
		1432	See the L<AE> manpage for details.
		1433
		1434	=cut
		1435
		1436	package AE;
		1437
		1438	our $VERSION = $AnyEvent::VERSION;
		1439
		1440	sub _reset() {
		1441	eval q{
		1442	# fall back to the main API by default - backends and AnyEvent::Base
		1443	# implementations can overwrite these.
		1444
		1445	sub io($$$) {
		1446	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1447	}
		1448
		1449	sub timer($$$) {
		1450	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1451	}
		1452
		1453	sub signal($$) {
		1454	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1455	}
		1456
		1457	sub child($$) {
		1458	AnyEvent->child (pid => $_[0], cb => $_[1])
		1459	}
		1460
		1461	sub idle($) {
		1462	AnyEvent->idle (cb => $_[0]);
		1463	}
		1464
		1465	sub cv(;&) {
		1466	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1467	}
		1468
		1469	sub now() {
		1470	AnyEvent->now
		1471	}
		1472
		1473	sub now_update() {
		1474	AnyEvent->now_update
		1475	}
		1476
		1477	sub time() {
		1478	AnyEvent->time
		1479	}
		1480
		1481	*postpone = \&AnyEvent::postpone;
		1482	};
		1483	die if $@;
		1484	}
		1485
		1486	BEGIN { _reset }
		1487
1227	package AnyEvent::Base;	1488	package AnyEvent::Base;
1228		1489
1229	# default implementations for many methods	1490	# default implementations for many methods
1230		1491
1231	sub _time {	1492	sub time {
		1493	eval q{ # poor man's autoloading {}
1232	# probe for availability of Time::HiRes	1494	# probe for availability of Time::HiRes
1233	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1495	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1234	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1496	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1235	*_time = \&Time::HiRes::time;	1497	*AE::time = \&Time::HiRes::time;
1236	# if (eval "use POSIX (); (POSIX::times())...	1498	# if (eval "use POSIX (); (POSIX::times())...
1237	} else {	1499	} else {
1238	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1500	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1239	*_time = sub { time }; # epic fail	1501	*AE::time = sub (){ time }; # epic fail
		1502	}
		1503
		1504	*time = sub { AE::time }; # different prototypes
1240	}	1505	};
		1506	die if $@;
1241		1507
1242	&_time	1508	&time
1243	}	1509	}
1244		1510
1245	sub time { _time }	1511	*now = \&time;
1246	sub now { _time }	1512
1247	sub now_update { }	1513	sub now_update { }
1248		1514
		1515	sub _poll {
		1516	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1517	}
		1518
1249	# default implementation for ->condvar	1519	# default implementation for ->condvar
		1520	# in fact, the default should not be overwritten
1250		1521
1251	sub condvar {	1522	sub condvar {
		1523	eval q{ # poor man's autoloading {}
		1524	*condvar = sub {
1252	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1525	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1526	};
		1527
		1528	*AE::cv = sub (;&) {
		1529	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1530	};
		1531	};
		1532	die if $@;
		1533
		1534	&condvar
1253	}	1535	}
1254		1536
1255	# default implementation for ->signal	1537	# default implementation for ->signal
1256		1538
1257	our $HAVE_ASYNC_INTERRUPT;	1539	our $HAVE_ASYNC_INTERRUPT;
		1540
		1541	sub _have_async_interrupt() {
		1542	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1543	&& eval "use Async::Interrupt 1.02 (); 1")
		1544	unless defined $HAVE_ASYNC_INTERRUPT;
		1545
		1546	$HAVE_ASYNC_INTERRUPT
		1547	}
		1548
1258	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1549	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1259	our (%SIG_ASY, %SIG_ASY_W);	1550	our (%SIG_ASY, %SIG_ASY_W);
1260	our ($SIG_COUNT, $SIG_TW);	1551	our ($SIG_COUNT, $SIG_TW);
1261		1552
1262	sub _signal_exec {	1553	# install a dummy wakeup watcher to reduce signal catching latency
1263	$HAVE_ASYNC_INTERRUPT	1554	# used by Impls
1264	? $SIGPIPE_R->drain	1555	sub _sig_add() {
1265	: sysread $SIGPIPE_R, my $dummy, 9;	1556	unless ($SIG_COUNT++) {
		1557	# try to align timer on a full-second boundary, if possible
		1558	my $NOW = AE::now;
1266		1559
1267	while (%SIG_EV) {	1560	$SIG_TW = AE::timer
1268	for (keys %SIG_EV) {	1561	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1269	delete $SIG_EV{$_};	1562	$MAX_SIGNAL_LATENCY,
1270	$_->() for values %{ $SIG_CB{$_} || {} };	1563	sub { } # just for the PERL_ASYNC_CHECK
1271	}	1564	;
1272	}	1565	}
1273	}	1566	}
1274		1567
1275	sub _signal {	1568	sub _sig_del {
1276	my (undef, %arg) = @_;
1277
1278	my $signal = uc $arg{signal}
1279	or Carp::croak "required option 'signal' is missing";
1280
1281	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1282
1283	if ($HAVE_ASYNC_INTERRUPT) {
1284	# async::interrupt
1285
1286	$SIG_ASY{$signal} ||= do {
1287	my $asy = new Async::Interrupt
1288	cb => sub { undef $SIG_EV{$signal} },
1289	signal => $signal,
1290	pipe => [$SIGPIPE_R->filenos],
1291	;
1292	$asy->pipe_autodrain (0);
1293
1294	$asy
1295	};
1296
1297	} else {
1298	# pure perl
1299
1300	$SIG{$signal} ||= sub {
1301	local $!;
1302	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1303	undef $SIG_EV{$signal};
1304	};
1305
1306	# can't do signal processing without introducing races in pure perl,
1307	# so limit the signal latency.
1308	++$SIG_COUNT;
1309	$SIG_TW ||= AnyEvent->timer (
1310	after => $MAX_SIGNAL_LATENCY,
1311	interval => $MAX_SIGNAL_LATENCY,
1312	cb => sub { }, # just for the PERL_ASYNC_CHECK
1313	);
1314	}
1315
1316	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1317	}
1318
1319	sub signal {
1320	# probe for availability of Async::Interrupt
1321	if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1322	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1323
1324	$HAVE_ASYNC_INTERRUPT = 1;
1325	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1326	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1327
1328	} else {
1329	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1330
1331	require Fcntl;
1332
1333	if (AnyEvent::WIN32) {
1334	require AnyEvent::Util;
1335
1336	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1337	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1338	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1339	} else {
1340	pipe $SIGPIPE_R, $SIGPIPE_W;
1341	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1342	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1343
1344	# not strictly required, as $^F is normally 2, but let's make sure...
1345	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1346	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1347	}
1348
1349	$SIGPIPE_R
1350	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1351
1352	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1353	}
1354
1355	*signal = \&_signal;
1356	&signal
1357	}
1358
1359	sub AnyEvent::Base::signal::DESTROY {
1360	my ($signal, $cb) = @{$_[0]};
1361
1362	undef $SIG_TW	1569	undef $SIG_TW
1363	unless --$SIG_COUNT;	1570	unless --$SIG_COUNT;
		1571	}
1364		1572
		1573	our $_sig_name_init; $_sig_name_init = sub {
		1574	eval q{ # poor man's autoloading {}
		1575	undef $_sig_name_init;
		1576
		1577	if (_have_async_interrupt) {
		1578	*sig2num = \&Async::Interrupt::sig2num;
		1579	*sig2name = \&Async::Interrupt::sig2name;
		1580	} else {
		1581	require Config;
		1582
		1583	my %signame2num;
		1584	@signame2num{ split ' ', $Config::Config{sig_name} }
		1585	= split ' ', $Config::Config{sig_num};
		1586
		1587	my @signum2name;
		1588	@signum2name[values %signame2num] = keys %signame2num;
		1589
		1590	*sig2num = sub($) {
		1591	$_[0] > 0 ? shift : $signame2num{+shift}
		1592	};
		1593	*sig2name = sub ($) {
		1594	$_[0] > 0 ? $signum2name[+shift] : shift
		1595	};
		1596	}
		1597	};
		1598	die if $@;
		1599	};
		1600
		1601	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1602	sub sig2name($) { &$_sig_name_init; &sig2name }
		1603
		1604	sub signal {
		1605	eval q{ # poor man's autoloading {}
		1606	# probe for availability of Async::Interrupt
		1607	if (_have_async_interrupt) {
		1608	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
		1609
		1610	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1611	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
		1612
		1613	} else {
		1614	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1615
		1616	if (AnyEvent::WIN32) {
		1617	require AnyEvent::Util;
		1618
		1619	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1620	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1621	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1622	} else {
		1623	pipe $SIGPIPE_R, $SIGPIPE_W;
		1624	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
		1625	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1626
		1627	# not strictly required, as $^F is normally 2, but let's make sure...
		1628	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1629	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1630	}
		1631
		1632	$SIGPIPE_R
		1633	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1634
		1635	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
		1636	}
		1637
		1638	*signal = $HAVE_ASYNC_INTERRUPT
		1639	? sub {
		1640	my (undef, %arg) = @_;
		1641
		1642	# async::interrupt
		1643	my $signal = sig2num $arg{signal};
		1644	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1645
		1646	$SIG_ASY{$signal} ||= new Async::Interrupt
		1647	cb => sub { undef $SIG_EV{$signal} },
		1648	signal => $signal,
		1649	pipe => [$SIGPIPE_R->filenos],
		1650	pipe_autodrain => 0,
		1651	;
		1652
		1653	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1654	}
		1655	: sub {
		1656	my (undef, %arg) = @_;
		1657
		1658	# pure perl
		1659	my $signal = sig2name $arg{signal};
		1660	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1661
		1662	$SIG{$signal} ||= sub {
		1663	local $!;
		1664	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1665	undef $SIG_EV{$signal};
		1666	};
		1667
		1668	# can't do signal processing without introducing races in pure perl,
		1669	# so limit the signal latency.
		1670	_sig_add;
		1671
		1672	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1673	}
		1674	;
		1675
		1676	*AnyEvent::Base::signal::DESTROY = sub {
		1677	my ($signal, $cb) = @{$_[0]};
		1678
		1679	_sig_del;
		1680
1365	delete $SIG_CB{$signal}{$cb};	1681	delete $SIG_CB{$signal}{$cb};
1366		1682
		1683	$HAVE_ASYNC_INTERRUPT
		1684	? delete $SIG_ASY{$signal}
1367	# delete doesn't work with older perls - they then	1685	: # delete doesn't work with older perls - they then
1368	# print weird messages, or just unconditionally exit	1686	# print weird messages, or just unconditionally exit
1369	# instead of getting the default action.	1687	# instead of getting the default action.
1370	undef $SIG{$signal}	1688	undef $SIG{$signal}
1371	unless keys %{ $SIG_CB{$signal} };	1689	unless keys %{ $SIG_CB{$signal} };
		1690	};
		1691
		1692	*_signal_exec = sub {
		1693	$HAVE_ASYNC_INTERRUPT
		1694	? $SIGPIPE_R->drain
		1695	: sysread $SIGPIPE_R, (my $dummy), 9;
		1696
		1697	while (%SIG_EV) {
		1698	for (keys %SIG_EV) {
		1699	delete $SIG_EV{$_};
		1700	&$_ for values %{ $SIG_CB{$_} || {} };
		1701	}
		1702	}
		1703	};
		1704	};
		1705	die if $@;
		1706
		1707	&signal
1372	}	1708	}
1373		1709
1374	# default implementation for ->child	1710	# default implementation for ->child
1375		1711
1376	our %PID_CB;	1712	our %PID_CB;
1377	our $CHLD_W;	1713	our $CHLD_W;
1378	our $CHLD_DELAY_W;	1714	our $CHLD_DELAY_W;
1379	our $WNOHANG;
1380		1715
1381	sub _sigchld {	1716	# used by many Impl's
1382	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1717	sub _emit_childstatus($$) {
1383	$_->($pid, $?)	1718	my (undef, $rpid, $rstatus) = @_;
		1719
		1720	$_->($rpid, $rstatus)
1384	for values %{ $PID_CB{$pid} || {} },	1721	for values %{ $PID_CB{$rpid} || {} },
1385	values %{ $PID_CB{0} || {} };	1722	values %{ $PID_CB{0} || {} };
1386	}
1387	}	1723	}
1388		1724
1389	sub child {	1725	sub child {
		1726	eval q{ # poor man's autoloading {}
		1727	*_sigchld = sub {
		1728	my $pid;
		1729
		1730	AnyEvent->_emit_childstatus ($pid, $?)
		1731	while ($pid = waitpid -1, WNOHANG) > 0;
		1732	};
		1733
		1734	*child = sub {
1390	my (undef, %arg) = @_;	1735	my (undef, %arg) = @_;
1391		1736
1392	defined (my $pid = $arg{pid} + 0)	1737	my $pid = $arg{pid};
1393	or Carp::croak "required option 'pid' is missing";	1738	my $cb = $arg{cb};
1394		1739
1395	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1740	$PID_CB{$pid}{$cb+0} = $cb;
1396		1741
1397	# WNOHANG is almost cetrainly 1 everywhere
1398	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1399	? 1
1400	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1401
1402	unless ($CHLD_W) {	1742	unless ($CHLD_W) {
1403	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1743	$CHLD_W = AE::signal CHLD => \&_sigchld;
1404	# child could be a zombie already, so make at least one round	1744	# child could be a zombie already, so make at least one round
1405	&_sigchld;	1745	&_sigchld;
1406	}	1746	}
1407		1747
1408	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1748	bless [$pid, $cb+0], "AnyEvent::Base::child"
1409	}	1749	};
1410		1750
1411	sub AnyEvent::Base::child::DESTROY {	1751	*AnyEvent::Base::child::DESTROY = sub {
1412	my ($pid, $cb) = @{$_[0]};	1752	my ($pid, $icb) = @{$_[0]};
1413		1753
1414	delete $PID_CB{$pid}{$cb};	1754	delete $PID_CB{$pid}{$icb};
1415	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1755	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1416		1756
1417	undef $CHLD_W unless keys %PID_CB;	1757	undef $CHLD_W unless keys %PID_CB;
		1758	};
		1759	};
		1760	die if $@;
		1761
		1762	&child
1418	}	1763	}
1419		1764
1420	# idle emulation is done by simply using a timer, regardless	1765	# idle emulation is done by simply using a timer, regardless
1421	# of whether the process is idle or not, and not letting	1766	# of whether the process is idle or not, and not letting
1422	# the callback use more than 50% of the time.	1767	# the callback use more than 50% of the time.
1423	sub idle {	1768	sub idle {
		1769	eval q{ # poor man's autoloading {}
		1770	*idle = sub {
1424	my (undef, %arg) = @_;	1771	my (undef, %arg) = @_;
1425		1772
1426	my ($cb, $w, $rcb) = $arg{cb};	1773	my ($cb, $w, $rcb) = $arg{cb};
1427		1774
1428	$rcb = sub {	1775	$rcb = sub {
1429	if ($cb) {	1776	if ($cb) {
1430	$w = _time;	1777	$w = AE::time;
1431	&$cb;	1778	&$cb;
1432	$w = _time - $w;	1779	$w = AE::time - $w;
1433		1780
1434	# never use more then 50% of the time for the idle watcher,	1781	# never use more then 50% of the time for the idle watcher,
1435	# within some limits	1782	# within some limits
1436	$w = 0.0001 if $w < 0.0001;	1783	$w = 0.0001 if $w < 0.0001;
1437	$w = 5 if $w > 5;	1784	$w = 5 if $w > 5;
1438		1785
1439	$w = AnyEvent->timer (after => $w, cb => $rcb);	1786	$w = AE::timer $w, 0, $rcb;
1440	} else {	1787	} else {
1441	# clean up...	1788	# clean up...
1442	undef $w;	1789	undef $w;
1443	undef $rcb;	1790	undef $rcb;
		1791	}
		1792	};
		1793
		1794	$w = AE::timer 0.05, 0, $rcb;
		1795
		1796	bless \\$cb, "AnyEvent::Base::idle"
1444	}	1797	};
		1798
		1799	*AnyEvent::Base::idle::DESTROY = sub {
		1800	undef $${$_[0]};
		1801	};
1445	};	1802	};
		1803	die if $@;
1446		1804
1447	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1805	&idle
1448
1449	bless \\$cb, "AnyEvent::Base::idle"
1450	}
1451
1452	sub AnyEvent::Base::idle::DESTROY {
1453	undef $${$_[0]};
1454	}	1806	}
1455		1807
1456	package AnyEvent::CondVar;	1808	package AnyEvent::CondVar;
1457		1809
1458	our @ISA = AnyEvent::CondVar::Base::;	1810	our @ISA = AnyEvent::CondVar::Base::;
		1811
		1812	# only to be used for subclassing
		1813	sub new {
		1814	my $class = shift;
		1815	bless AnyEvent->condvar (@_), $class
		1816	}
1459		1817
1460	package AnyEvent::CondVar::Base;	1818	package AnyEvent::CondVar::Base;
1461		1819
1462	#use overload	1820	#use overload
1463	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1821	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
…		…
1473		1831
1474	sub _send {	1832	sub _send {
1475	# nop	1833	# nop
1476	}	1834	}
1477		1835
		1836	sub _wait {
		1837	AnyEvent->_poll until $_[0]{_ae_sent};
		1838	}
		1839
1478	sub send {	1840	sub send {
1479	my $cv = shift;	1841	my $cv = shift;
1480	$cv->{_ae_sent} = [@_];	1842	$cv->{_ae_sent} = [@_];
1481	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};	1843	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1482	$cv->_send;	1844	$cv->_send;
…		…
1489		1851
1490	sub ready {	1852	sub ready {
1491	$_[0]{_ae_sent}	1853	$_[0]{_ae_sent}
1492	}	1854	}
1493		1855
1494	sub _wait {
1495	$WAITING
1496	and !$_[0]{_ae_sent}
1497	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1498
1499	local $WAITING = 1;
1500	AnyEvent->one_event while !$_[0]{_ae_sent};
1501	}
1502
1503	sub recv {	1856	sub recv {
		1857	unless ($_[0]{_ae_sent}) {
		1858	$WAITING
		1859	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1860
		1861	local $WAITING = 1;
1504	$_[0]->_wait;	1862	$_[0]->_wait;
		1863	}
1505		1864
1506	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1865	$_[0]{_ae_croak}
1507	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1866	and Carp::croak $_[0]{_ae_croak};
		1867
		1868	wantarray
		1869	? @{ $_[0]{_ae_sent} }
		1870	: $_[0]{_ae_sent}[0]
1508	}	1871	}
1509		1872
1510	sub cb {	1873	sub cb {
1511	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1874	my $cv = shift;
		1875
		1876	@_
		1877	and $cv->{_ae_cb} = shift
		1878	and $cv->{_ae_sent}
		1879	and (delete $cv->{_ae_cb})->($cv);
		1880
1512	$_[0]{_ae_cb}	1881	$cv->{_ae_cb}
1513	}	1882	}
1514		1883
1515	sub begin {	1884	sub begin {
1516	++$_[0]{_ae_counter};	1885	++$_[0]{_ae_counter};
1517	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1886	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1522	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	1891	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1523	}	1892	}
1524		1893
1525	# undocumented/compatibility with pre-3.4	1894	# undocumented/compatibility with pre-3.4
1526	*broadcast = \&send;	1895	*broadcast = \&send;
1527	*wait = \&_wait;	1896	*wait = \&recv;
1528		1897
1529	=head1 ERROR AND EXCEPTION HANDLING	1898	=head1 ERROR AND EXCEPTION HANDLING
1530		1899
1531	In general, AnyEvent does not do any error handling - it relies on the	1900	In general, AnyEvent does not do any error handling - it relies on the
1532	caller to do that if required. The L<AnyEvent::Strict> module (see also	1901	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1579	check the arguments passed to most method calls. If it finds any problems,	1948	check the arguments passed to most method calls. If it finds any problems,
1580	it will croak.	1949	it will croak.
1581		1950
1582	In other words, enables "strict" mode.	1951	In other words, enables "strict" mode.
1583		1952
1584	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	1953	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1585	>>, it is definitely recommended to keep it off in production. Keeping	1954	>>, it is definitely recommended to keep it off in production. Keeping
1586	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	1955	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1587	can be very useful, however.	1956	can be very useful, however.
1588		1957
		1958	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		1959
		1960	If this env variable is set, then its contents will be
		1961	interpreted by C<AnyEvent::Socket::parse_hostport> and an
		1962	C<AnyEvent::Debug::shell> is bound on that port. The shell object is saved
		1963	in C<$AnyEvent::Debug::SHELL>.
		1964
		1965	For example, to bind a debug shell on a unix domain socket in
		1966	F</tmp/debug.sock>, you could use this:
		1967
		1968	PERL_ANYEVENT_DEBUG_SHELL=unix/:/tmp/debug.sock perlprog
		1969
		1970	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		1971
		1972	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		1973	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
		1974
1589	=item C<PERL_ANYEVENT_MODEL>	1975	=item C<PERL_ANYEVENT_MODEL>
1590		1976
1591	This can be used to specify the event model to be used by AnyEvent, before	1977	This can be used to specify the event model to be used by AnyEvent, before
1592	auto detection and -probing kicks in. It must be a string consisting	1978	auto detection and -probing kicks in.
1593	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1979
		1980	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		1981	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1594	and the resulting module name is loaded and if the load was successful,	1982	resulting module name is loaded and - if the load was successful - used as
1595	used as event model. If it fails to load AnyEvent will proceed with	1983	event model backend. If it fails to load then AnyEvent will proceed with
1596	auto detection and -probing.	1984	auto detection and -probing.
1597		1985
1598	This functionality might change in future versions.	1986	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		1987	nothing gets prepended and the module name is used as-is (hint: C<::> at
		1988	the end of a string designates a module name and quotes it appropriately).
1599		1989
1600	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1990	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1601	could start your program like this:	1991	could start your program like this:
1602		1992
1603	PERL_ANYEVENT_MODEL=Perl perl ...	1993	PERL_ANYEVENT_MODEL=Perl perl ...
1604		1994
1605	=item C<PERL_ANYEVENT_PROTOCOLS>	1995	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
1726	warn "read: $input\n"; # output what has been read	2116	warn "read: $input\n"; # output what has been read
1727	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2117	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1728	},	2118	},
1729	);	2119	);
1730		2120
1731	my $time_watcher; # can only be used once
1732
1733	sub new_timer {
1734	$timer = AnyEvent->timer (after => 1, cb => sub {	2121	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1735	warn "timeout\n"; # print 'timeout' about every second	2122	warn "timeout\n"; # print 'timeout' at most every second
1736	&new_timer; # and restart the time
1737	});	2123	});
1738	}
1739
1740	new_timer; # create first timer
1741		2124
1742	$cv->recv; # wait until user enters /^q/i	2125	$cv->recv; # wait until user enters /^q/i
1743		2126
1744	=head1 REAL-WORLD EXAMPLE	2127	=head1 REAL-WORLD EXAMPLE
1745		2128
…		…
1818		2201
1819	The actual code goes further and collects all errors (C<die>s, exceptions)	2202	The actual code goes further and collects all errors (C<die>s, exceptions)
1820	that occurred during request processing. The C<result> method detects	2203	that occurred during request processing. The C<result> method detects
1821	whether an exception as thrown (it is stored inside the $txn object)	2204	whether an exception as thrown (it is stored inside the $txn object)
1822	and just throws the exception, which means connection errors and other	2205	and just throws the exception, which means connection errors and other
1823	problems get reported tot he code that tries to use the result, not in a	2206	problems get reported to the code that tries to use the result, not in a
1824	random callback.	2207	random callback.
1825		2208
1826	All of this enables the following usage styles:	2209	All of this enables the following usage styles:
1827		2210
1828	1. Blocking:	2211	1. Blocking:
…		…
1876	through AnyEvent. The benchmark creates a lot of timers (with a zero	2259	through AnyEvent. The benchmark creates a lot of timers (with a zero
1877	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2260	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1878	which it is), lets them fire exactly once and destroys them again.	2261	which it is), lets them fire exactly once and destroys them again.
1879		2262
1880	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2263	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1881	distribution.	2264	distribution. It uses the L<AE> interface, which makes a real difference
		2265	for the EV and Perl backends only.
1882		2266
1883	=head3 Explanation of the columns	2267	=head3 Explanation of the columns
1884		2268
1885	I<watcher> is the number of event watchers created/destroyed. Since	2269	I<watcher> is the number of event watchers created/destroyed. Since
1886	different event models feature vastly different performances, each event	2270	different event models feature vastly different performances, each event
…		…
1907	watcher.	2291	watcher.
1908		2292
1909	=head3 Results	2293	=head3 Results
1910		2294
1911	name watchers bytes create invoke destroy comment	2295	name watchers bytes create invoke destroy comment
1912	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2296	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1913	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2297	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1914	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2298	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1915	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2299	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1916	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2300	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1917	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2301	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1918	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2302	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1919	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2303	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1920	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2304	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1921	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2305	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1922	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2306	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1923	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2307	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1924		2308
1925	=head3 Discussion	2309	=head3 Discussion
1926		2310
1927	The benchmark does I<not> measure scalability of the event loop very	2311	The benchmark does I<not> measure scalability of the event loop very
1928	well. For example, a select-based event loop (such as the pure perl one)	2312	well. For example, a select-based event loop (such as the pure perl one)
…		…
1940	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2324	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1941	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2325	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1942	cycles with POE.	2326	cycles with POE.
1943		2327
1944	C<EV> is the sole leader regarding speed and memory use, which are both	2328	C<EV> is the sole leader regarding speed and memory use, which are both
1945	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2329	maximal/minimal, respectively. When using the L<AE> API there is zero
		2330	overhead (when going through the AnyEvent API create is about 5-6 times
		2331	slower, with other times being equal, so still uses far less memory than
1946	far less memory than any other event loop and is still faster than Event	2332	any other event loop and is still faster than Event natively).
1947	natively.
1948		2333
1949	The pure perl implementation is hit in a few sweet spots (both the	2334	The pure perl implementation is hit in a few sweet spots (both the
1950	constant timeout and the use of a single fd hit optimisations in the perl	2335	constant timeout and the use of a single fd hit optimisations in the perl
1951	interpreter and the backend itself). Nevertheless this shows that it	2336	interpreter and the backend itself). Nevertheless this shows that it
1952	adds very little overhead in itself. Like any select-based backend its	2337	adds very little overhead in itself. Like any select-based backend its
…		…
2026	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2411	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2027	(1%) are active. This mirrors the activity of large servers with many	2412	(1%) are active. This mirrors the activity of large servers with many
2028	connections, most of which are idle at any one point in time.	2413	connections, most of which are idle at any one point in time.
2029		2414
2030	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2415	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2031	distribution.	2416	distribution. It uses the L<AE> interface, which makes a real difference
		2417	for the EV and Perl backends only.
2032		2418
2033	=head3 Explanation of the columns	2419	=head3 Explanation of the columns
2034		2420
2035	I<sockets> is the number of sockets, and twice the number of "servers" (as	2421	I<sockets> is the number of sockets, and twice the number of "servers" (as
2036	each server has a read and write socket end).	2422	each server has a read and write socket end).
…		…
2044	a new one that moves the timeout into the future.	2430	a new one that moves the timeout into the future.
2045		2431
2046	=head3 Results	2432	=head3 Results
2047		2433
2048	name sockets create request	2434	name sockets create request
2049	EV 20000 69.01 11.16	2435	EV 20000 62.66 7.99
2050	Perl 20000 73.32 35.87	2436	Perl 20000 68.32 32.64
2051	IOAsync 20000 157.00 98.14 epoll	2437	IOAsync 20000 174.06 101.15 epoll
2052	IOAsync 20000 159.31 616.06 poll	2438	IOAsync 20000 174.67 610.84 poll
2053	Event 20000 212.62 257.32	2439	Event 20000 202.69 242.91
2054	Glib 20000 651.16 1896.30	2440	Glib 20000 557.01 1689.52
2055	POE 20000 349.67 12317.24 uses POE::Loop::Event	2441	POE 20000 341.54 12086.32 uses POE::Loop::Event
2056		2442
2057	=head3 Discussion	2443	=head3 Discussion
2058		2444
2059	This benchmark I<does> measure scalability and overall performance of the	2445	This benchmark I<does> measure scalability and overall performance of the
2060	particular event loop.	2446	particular event loop.
…		…
2186	As you can see, the AnyEvent + EV combination even beats the	2572	As you can see, the AnyEvent + EV combination even beats the
2187	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2573	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2188	backend easily beats IO::Lambda and POE.	2574	backend easily beats IO::Lambda and POE.
2189		2575
2190	And even the 100% non-blocking version written using the high-level (and	2576	And even the 100% non-blocking version written using the high-level (and
2191	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2577	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2192	large margin, even though it does all of DNS, tcp-connect and socket I/O	2578	higher level ("unoptimised") abstractions by a large margin, even though
2193	in a non-blocking way.	2579	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2194		2580
2195	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2581	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2196	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2582	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2197	part of the IO::lambda distribution and were used without any changes.	2583	part of the IO::Lambda distribution and were used without any changes.
2198		2584
2199		2585
2200	=head1 SIGNALS	2586	=head1 SIGNALS
2201		2587
2202	AnyEvent currently installs handlers for these signals:	2588	AnyEvent currently installs handlers for these signals:
…		…
2239	unless defined $SIG{PIPE};	2625	unless defined $SIG{PIPE};
2240		2626
2241	=head1 RECOMMENDED/OPTIONAL MODULES	2627	=head1 RECOMMENDED/OPTIONAL MODULES
2242		2628
2243	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2629	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2244	it's built-in modules) are required to use it.	2630	its built-in modules) are required to use it.
2245		2631
2246	That does not mean that AnyEvent won't take advantage of some additional	2632	That does not mean that AnyEvent won't take advantage of some additional
2247	modules if they are installed.	2633	modules if they are installed.
2248		2634
2249	This section epxlains which additional modules will be used, and how they	2635	This section explains which additional modules will be used, and how they
2250	affect AnyEvent's operetion.	2636	affect AnyEvent's operation.
2251		2637
2252	=over 4	2638	=over 4
2253		2639
2254	=item L<Async::Interrupt>	2640	=item L<Async::Interrupt>
2255		2641
2256	This slightly arcane module is used to implement fast signal handling: To	2642	This slightly arcane module is used to implement fast signal handling: To
2257	my knowledge, there is no way to do completely race-free and quick	2643	my knowledge, there is no way to do completely race-free and quick
2258	signal handling in pure perl. To ensure that signals still get	2644	signal handling in pure perl. To ensure that signals still get
2259	delivered, AnyEvent will start an interval timer to wake up perl (and	2645	delivered, AnyEvent will start an interval timer to wake up perl (and
2260	catch the signals) with soemd elay (default is 10 seconds, look for	2646	catch the signals) with some delay (default is 10 seconds, look for
2261	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2647	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2262		2648
2263	If this module is available, then it will be used to implement signal	2649	If this module is available, then it will be used to implement signal
2264	catching, which means that signals will not be delayed, and the event loop	2650	catching, which means that signals will not be delayed, and the event loop
2265	will not be interrupted regularly, which is more efficient (And good for	2651	will not be interrupted regularly, which is more efficient (and good for
2266	battery life on laptops).	2652	battery life on laptops).
2267		2653
2268	This affects not just the pure-perl event loop, but also other event loops	2654	This affects not just the pure-perl event loop, but also other event loops
2269	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2655	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2656
		2657	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2658	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2659	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2660	does nothing for those backends.
2270		2661
2271	=item L<EV>	2662	=item L<EV>
2272		2663
2273	This module isn't really "optional", as it is simply one of the backend	2664	This module isn't really "optional", as it is simply one of the backend
2274	event loops that AnyEvent can use. However, it is simply the best event	2665	event loops that AnyEvent can use. However, it is simply the best event
…		…
2277	automatic timer adjustments even when no monotonic clock is available,	2668	automatic timer adjustments even when no monotonic clock is available,
2278	can take avdantage of advanced kernel interfaces such as C<epoll> and	2669	can take avdantage of advanced kernel interfaces such as C<epoll> and
2279	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2670	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2280	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2671	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2281		2672
		2673	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2674	then this module will do nothing for you.
		2675
2282	=item L<Guard>	2676	=item L<Guard>
2283		2677
2284	The guard module, when used, will be used to implement	2678	The guard module, when used, will be used to implement
2285	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2679	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2286	lot less memory), but otherwise doesn't affect guard operation much. It is	2680	lot less memory), but otherwise doesn't affect guard operation much. It is
2287	purely used for performance.	2681	purely used for performance.
2288		2682
2289	=item L<JSON> and L<JSON::XS>	2683	=item L<JSON> and L<JSON::XS>
2290		2684
2291	This module is required when you want to read or write JSON data via	2685	One of these modules is required when you want to read or write JSON data
2292	L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2686	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2293	advantage of the ulta-high-speed L<JSON::XS> module when it is installed.	2687	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2294
2295	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2296	installed.
2297		2688
2298	=item L<Net::SSLeay>	2689	=item L<Net::SSLeay>
2299		2690
2300	Implementing TLS/SSL in Perl is certainly interesting, but not very	2691	Implementing TLS/SSL in Perl is certainly interesting, but not very
2301	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2692	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2302	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2693	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2303		2694
2304	=item L<Time::HiRes>	2695	=item L<Time::HiRes>
2305		2696
2306	This module is part of perl since release 5.008. It will be used when the	2697	This module is part of perl since release 5.008. It will be used when the
2307	chosen event library does not come with a timing source on it's own. The	2698	chosen event library does not come with a timing source of its own. The
2308	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2699	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2309	try to use a monotonic clock for timing stability.	2700	try to use a monotonic clock for timing stability.
2310		2701
2311	=back	2702	=back
2312		2703
2313		2704
2314	=head1 FORK	2705	=head1 FORK
2315		2706
2316	Most event libraries are not fork-safe. The ones who are usually are	2707	Most event libraries are not fork-safe. The ones who are usually are
2317	because they rely on inefficient but fork-safe C<select> or C<poll>	2708	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2318	calls. Only L<EV> is fully fork-aware.	2709	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2710	are usually badly thought-out hacks that are incompatible with fork in
		2711	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2712	continue event-processing in both parent and child (or both, if you know
		2713	what you are doing).
		2714
		2715	This means that, in general, you cannot fork and do event processing in
		2716	the child if the event library was initialised before the fork (which
		2717	usually happens when the first AnyEvent watcher is created, or the library
		2718	is loaded).
2319		2719
2320	If you have to fork, you must either do so I<before> creating your first	2720	If you have to fork, you must either do so I<before> creating your first
2321	watcher OR you must not use AnyEvent at all in the child OR you must do	2721	watcher OR you must not use AnyEvent at all in the child OR you must do
2322	something completely out of the scope of AnyEvent.	2722	something completely out of the scope of AnyEvent.
		2723
		2724	The problem of doing event processing in the parent I<and> the child
		2725	is much more complicated: even for backends that I<are> fork-aware or
		2726	fork-safe, their behaviour is not usually what you want: fork clones all
		2727	watchers, that means all timers, I/O watchers etc. are active in both
		2728	parent and child, which is almost never what you want. USing C<exec>
		2729	to start worker children from some kind of manage rprocess is usually
		2730	preferred, because it is much easier and cleaner, at the expense of having
		2731	to have another binary.
2323		2732
2324		2733
2325	=head1 SECURITY CONSIDERATIONS	2734	=head1 SECURITY CONSIDERATIONS
2326		2735
2327	AnyEvent can be forced to load any event model via	2736	AnyEvent can be forced to load any event model via
…		…
2357	pronounced).	2766	pronounced).
2358		2767
2359		2768
2360	=head1 SEE ALSO	2769	=head1 SEE ALSO
2361		2770
		2771	Tutorial/Introduction: L<AnyEvent::Intro>.
		2772
		2773	FAQ: L<AnyEvent::FAQ>.
		2774
2362	Utility functions: L<AnyEvent::Util>.	2775	Utility functions: L<AnyEvent::Util>.
2363		2776
2364	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2777	Event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>, L<Glib::EV>,
2365	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2778	L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2366		2779
2367	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2780	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2368	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2781	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2369	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2782	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2370	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.	2783	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2371		2784
2372	Non-blocking file handles, sockets, TCP clients and	2785	Non-blocking file handles, sockets, TCP clients and
2373	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2786	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2374		2787
2375	Asynchronous DNS: L<AnyEvent::DNS>.	2788	Asynchronous DNS: L<AnyEvent::DNS>.
2376		2789
2377	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	2790	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2378	L<Coro::Event>,
2379		2791
2380	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	2792	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2381	L<AnyEvent::HTTP>.	2793	L<AnyEvent::HTTP>.
2382		2794
2383		2795
2384	=head1 AUTHOR	2796	=head1 AUTHOR
2385		2797

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